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  • 1.
    af Bjerkén, Sara
    et al.
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Boger, Heather A
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Nelson, Matthew
    Hoffer, Barry J
    Granholm, Ann-Charlotte
    Strömberg, Ingrid
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Effects of glial cell line-derived neurotrophic factor deletion on ventral mesencephalic organotypic tissue cultures.2007Inngår i: Brain Research, ISSN 0006-8993, Vol. 1133, nr 1, 10-9 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Glial cell line-derived neurotrophic factor (GDNF) is potent for survival and promotion of nerve fibers from midbrain dopamine neurons. It is also known to exert different effects on specific subpopulations of dopamine neurons. In organotypic tissue cultures, dopamine neurons form two diverse nerve fiber growth patterns, targeting the striatum differently. The aim of this study was to investigate the effect of GDNF on the formation of dopamine nerve fibers. Organotypic tissue cultures of ventral mesencephalon of gdnf gene-deleted mice were studied. The results revealed that dopamine neurons survive in the absence of GDNF. Tyrosine hydroxylase immunoreactivity demonstrated, in gdnf knockout and wildtype cultures, nerve fiber formation with two separate morphologies occurring either in the absence or the presence of astrocytes. The outgrowth that occurred in the absence of astrocytes was unaffected by gdnf deletion, whereas nerve fibers guided by the presence of astrocytes were affected in that they reached significantly shorter distances from the gdnf gene-deleted tissue slice, compared to those measured in wildtype cultures. Treatment with GDNF reversed this effect and increased nerve fiber density independent of genotype. Furthermore, migration of astrocytes reached significantly shorter distances from the tissue slice in GDNF knockout compared to wildtype cultures. Exogenous GDNF increased astrocytic migration in gdnf gene-deleted tissue cultures, comparable to lengths observed in wildtype tissue cultures. In conclusion, cultured midbrain dopamine neurons survive in the absence of GDNF, and the addition of GDNF improved dopamine nerve fiber formation - possibly as an indirect effect of astrocytic stimulation.

  • 2.
    af Bjerkén, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Marschinke, Franziska
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Inhibition of astrocytes promotes long-distance growing nerve fibers in ventral mesencephalic cultures2008Inngår i: International Journal of Developmental Neuroscience, ISSN 0736-5748, E-ISSN 1873-474X, Vol. 26, nr 7, 683-691 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tyrosine hydroxylase-positive nerve fiber formation occurs in two diverse morphological patterns in rat fetal ventral mesencephalic slice cultures; one is non-glial-associated and the other is glial-associated. The aim of this study was to characterize the non-glial-associated nerve fibers and its relation to migration of astrocytes. Organotypic slice cultures were prepared from embryonic days 12, 14, and 18 rat fetuses and maintained for 5, 7 or 14 days in vitro. Inhibition of cell proliferation using cytosine beta-D-arabinofuranoside was conducted in embryonic day 14 ventral mesencephalic cultures. The treatment impaired astrocytic migration at 7 and 14 days in vitro. The reduced migration of astrocytes exerted a negative effect on the glial-associated tyrosine hydroxylase-positive nerve fibers, reducing the outgrowth from the tissue slice. The non-glial-associated outgrowth was, however, positively affected by reduced astrocytic migration, reaching distances around 3mm in 2 weeks, and remained for longer time in culture. Co-cultures of fetal ventral mesencephalon and frontal cortex revealed the cortex as a target for the non-glial-associated tyrosine hydroxylase-positive outgrowth. The age of the fetal tissue at plating affected the astrocytes such that older tissue increased the length of astrocyte migration. Younger tissue at plating promoted the presence of non-glial-associated outgrowth and long radial-glia-like processes, while older tissue promoted migration of neurons instead of formation of nerve fiber network. In conclusion, inhibition of astrocytic proliferation promotes the persistence of long-distance growing tyrosine hydroxylase-positive nerve fibers in ventral mesencephalic slices cultures. Furthermore, the long-distance growing nerve fibers target the frontal cortex and are absent in cultures derived from older tissue.

  • 3.
    af Bjerkén, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Nevalainen, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Lundblad, Martin
    Pomerleau, Francois
    Gerhardt, Greg A.
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    L-DOPA conversion to dopamine in the rat dopamine-depleted striatumManuskript (Annet vitenskapelig)
  • 4.
    Andersson, Mikael
    et al.
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Terasmaa, Anton
    Fuxe, Kjell
    Strömberg, Ingrid
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Subchronic haloperidol increases CB(1) receptor binding and G protein coupling in discrete regions of the basal ganglia.2005Inngår i: Journal of Neuroscience Research, ISSN 0360-4012, Vol. 82, nr 2, 264-72 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present study was designed to test whether chronic neuroleptic treatment, which is known to alter both expression and density of dopamine D(2) receptors in striatal regions, has effects upon function and binding level of the cannabinoid CB(1) receptor in the basal ganglia by using receptor autoradiography. As predicted, subchronic haloperidol treatment resulted in increased binding of (3)H-raclopride and quinpirole-induced guanosine 5'-O-(gamma-[(35)S]thio)triphosphate ([(35)S]GTPgammaS) in the striatum when compared to that measured in control animals. This increased D(2) receptor binding and function after 3 days washout was normalized after a 2-week washout period. Effect of haloperidol treatment was studied for CB(1) receptor binding and CP55,940-stimulated [(35)S]GTPgammaS in the striatum, globus pallidus, and substantia nigra. (3)[H]CP55,940 binding levels were found in rank order from highest to lowest in substantia nigra > globus pallidus > striatum. Furthermore, subchronic haloperidol treatment resulted in elevated binding levels of (3)[H]CP55,940 in the striatum and the substantia nigra and CB(1) receptor-stimulated [(35)S]GTPgammaS bindings in the substantia nigra after 3 days washout. These increased binding levels were normalized at 1-4 weeks after termination of haloperidol treatment. Haloperidol treatment had no significant effect on CB(1) receptor or [(35)S]GTPgammaS binding levels in globus pallidus. The results help to elucidate the underlying biochemical mechanism of CB(1) receptor supersensitivity after haloperidol treatment.

  • 5.
    Asplund, Kjell
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Axelsen, Mette
    Berglund, Göran
    Berne, Christian
    Karlström, Brita
    Lindahl, Bernt
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Lindblom, Jonas
    Norlund, Anders
    Rosén, Måns
    Ränzlöv, Ewalotte
    Toft, Eva
    Täljedal, Inge-Bert
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Wolk, Alicja
    Mat vid diabetes. En systematisk litteraturöversikt.2010Rapport (Annet vitenskapelig)
  • 6.
    Berglöf, Elisabet
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Dopamine neurons in ventral mesencephalon: interactions with glia and locus coeruleus2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Parkinson’s disease is a progressive neurodegenerative disorder, characterized by a depletion of the dopaminergic neurons in the substantia nigra. The cause of the disease is yet unknown but age, oxidative stress, and neuroinflammation are some of the features involved in the degeneration. In addition, substantial cell death of noradrenergic neurons occurs in the locus coeruleus (LC). Noradrenaline has been suggested to protect the dopamine neurons from oxidative stress and neuroinflammation. The main treatment of Parkinson’s disease is Levo-dopa, although severe side effects arise from this therapy. Hence, grafting fetal ventral mesencephalic (VM) tissue into the adult striatum has been evaluated as an alternative treatment for Parkinsons’s disease. However, the survival of the grafted neurons is limited, and the dopamine-denervated striatum does not become fully reinnervated. Therefore, elucidating factors that enhance dopamine nerve fiber formation and/or survival of the grafted neurons is of utmost importance.

    To investigate dopamine nerve fiber formation and the interactions with glial cells, organotypic VM tissue cultures were utilized. Two morphologically different nerve fiber outgrowths from the tissue slice were observed. Nerve fibers were initially formed in the absence of migrating astrocytes, although thin vimentin-positive astrocytic processes were detected within the same area. A second, persistent nerve fiber outgrowth was observed associated with migrating astrocytes. Hence, both of these nerve fiber outgrowths were to some extent dependent on astrocytes, and appeared as a general feature since this phenomenon was demonstrated in β-tubulin, tyrosine hydroxylase (TH), and aldehyde dehydrogenase A1 (ALDH1)-positive nerve fibers. Neither oligodendrocytes (NG2-positive cells), nor microglia (Iba-1-positive cells) exerted any effect on these two neuronal growths. Since astrocytes appeared to influence the nerve fiber formation, the role of proteoglycans, i.e. extracellular matrix molecules produced by astrocytes, was investigated. β-xyloside was added to the cultures to inhibit proteoglycan synthesis. The results revealed a hampered astrocytic migration and proliferation, as well as a reduction of the glia-associated TH-positive nerve fiber outgrowth. Interestingly, the number of cultures displaying the non-glia-mediated TH-positive nerve fibers increased after β-xyloside treatment, although the amount of TH-protein was not altered. Thus, proteoglycans produced by astrocytes appeared to be important in affecting the dopamine nerve fiber formation.

    The noradrenaline neurons in LC have been suggested to protect dopamine neurons from damage. Therefore, the interaction between VM and LC was evaluated. Using the intraocular grafting method, fetal VM and LC were grafted either as single grafts or as VM+LC co-grafts. Additionally, the recipient animals received 2% blueberry-enriched diet. The direct contact of LC promoted graft volume and survival of TH-positive neurons in the VM grafts. The number of dopamine neurons, derived preferably from the A9 (ALDH1/TH-positive) was increased, whereas the dopamine neurons from the A10 (calbindin/TH-positive) were not affected. A dense dopamine-β-hydroxylase (DBH)-positive innervation was correlated to the improved survival. Blueberry-enriched diet enhanced the number of TH-positive neurons in VM, although the graft size was not altered. The combination of blueberries and the presence of LC did not yield additive effects on the survival of VM grafts. The attachment of VM or the addition of blueberries did not affect the survival of TH-positive neurons in LC grafts. The number of Iba-1-positive microglia was decreased in co-grafted VM compared to single VM transplants. The addition of blueberries reduced the number of Iba-1-positive microglia in single VM transplants. Hence, the direct contact of LC or the addition of blueberries enhanced the survival of VM grafts.

    Taken together, these data demonstrate novel findings regarding the importance of astrocytes for the nerve fiber formation of dopamine neurons. Further, both the direct attachment of LC or antioxidant-enriched diet promote the survival of fetal VM grafts, while LC is not affected.

  • 7.
    Berglöf, Elisabet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi. Histologi med cellbiologi.
    Af Bjerkén, Sara
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi. Histologi med cellbiologi.
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi. Histologi med cellbiologi.
    Glial influence on nerve fiber formation from rat ventral mesencephalic organotypic tissue cultures.2007Inngår i: Journal of Comparative Neurology, ISSN 0021-9967, Vol. 501, nr 3, 431-42 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rat fetal ventral mesencephalic organotypic cultures have demonstrated two morphologically different dopamine nerve fiber growth patterns, in which the initial nerve fibers are formed in the absence of astrocytes and the second wave is guided by astrocytes. In this study, the presence of subpopulations of dopamine neurons, other neuronal populations, and glial cells was determined. We used "roller-drum" organotypic cultures, and the results revealed that beta-tubulin-positive/tyrosine hydroxylase (TH)-negative nerve fibers were present as early as 1 day in vitro (DIV). A similar growth pattern produced by TH-positive neurons was present from 2 DIV. These neurites grew to reach distances over 4 mm and over time appeared to be degenerating. Thin, vimentin-positive processes were found among these nerve fibers. As the first growth was retracted, a second outgrowth was initiated and formed on migrating astrocytes. TH- and aldehyde dehydrogenase-1 (ALDH1)-positive nerve fibers formed both the nonglia-associated and the glia-associated outgrowth. In cultures with membrane inserts, only the glia-associated outgrowth was found. Vimentin-positive cells preceded migration of NG2-positive oligodendrocytes and Iba-1-positive microglia. Oligodendrocytes appeared not to be involved in guiding neuritic growth, but microglia was absent over areas dense with TH-positive neurons. In conclusion, in "roller-drum" cultures, nerve fibers are generally formed in two sequences. The early-formed nerve fibers grow in the presence of thin, vimentin-positive processes. The second nerve fiber outgrowth is formed on astroglia, with no correlation to the presence of oligodendrocytes or microglia. ALDH1-positive nerve fibers, presumably derived from A9 dopamine neurons, participate in formation of both sequences of outgrowth.

  • 8.
    Berglöf, Elisabet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Bickford, Paula C.
    Strömberg, Ingrid
    Blueberry-enriched diet enhances the survival of fetal ventral mesencephalic intraocular graftsManuskript (Annet vitenskapelig)
  • 9.
    Berglöf, Elisabet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Small, Brent J
    School of Aging Studies, University of South Florida, Tampa, Florida 33620.
    Bickford, Paula C
    Department of Neurosurgery and Department of Molecular Pharmacology and Physiology, University of South Florida and James A. Haley VA Medical Center, Tampa, Florida 33620.
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Beneficial effects of antioxidant-enriched diet for tyrosine hydroxylase-positive neurons in ventral mesencephalic tissue in oculo grafts2009Inngår i: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 515, nr 1, 72-82 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Supplementation of antioxidants to the diet has been proved to be beneficial in aging and after brain injury. Furthermore, it has been postulated that the locus coeruleus promotes survival of dopamine neurons. Thus, this study was performed to elucidate the effects of a blueberry-enriched diet on fetal ventral mesencephalic tissue in the presence or absence of locus coeruleus utilizing the in oculo grafting method. Sprague-Dawley rats were given control diet or diet supplemented with 2% blueberries, and solid tissue pieces of fetal locus coeruleus and ventral mesencephalon were implanted as single and co-grafts. The results revealed that the presence of locus coeruleus tissue or the addition of blueberries enhanced the survival of ventral mesencephalic tyrosine hydroxylase (TH)-positive neurons, whereas no additive effects were observed for the two treatments. The density of TH-positive nerve fibers in ventral mesencephalic tissue was significantly elevated when it was attached to the locus coeruleus or by blueberry treatment, whereas the innervation of dopamine-beta-hydroxylase-positive nerve fibers was not altered. The presence of locus coeruleus tissue or bluberry supplementation reduced the number of Iba-1-positive microglia in the ventral mesencephalic portion of single and co-grafts, respectively, whereas almost no OX6 immunoreactivity was found. Furthermore, neither the attachment of ventral mesencephalic tissue nor the addition of blueberries improved the survival of TH-positive neurons in the locus coerulean grafts. To conclude, locus coeruleus and blueberries are beneficial for the survival of fetal ventral mesencephalic tissue, findings that could be useful when grafting tissue in Parkinson's disease.

  • 10.
    Berglöf, Elisabet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Locus coeruleus promotes survival of dopamine neurons in ventral mesencephalon: An in oculo grafting study2009Inngår i: Experimental Neurology, ISSN 0014-4886, E-ISSN 1090-2430, Vol. 216, nr 1, 158-165 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Parkinson's disease is a neurodegenerative disorder where dopamine neurons in the substantia nigra of ventral mesencephalon undergo degeneration. In addition to the loss of dopamine neurons, noradrenaline neurons in the locus coeruleus degenerate, actually to a higher extent than the dopamine neurons. The interaction between these two nuclei is yet not fully known, hence this study was undertaken to investigate the role of locus coeruleus during development of dopamine neurons utilizing the intraocular grafting model. Fetal ventral mesencephalon and locus coeruleus were implanted either as single grafts or co-grafts, placed in direct contact or at a distance. The results revealed that the direct attachment of locus coeruleus to ventral mesencephalon enhanced graft volume and number of tyrosine hydroxylase (TH)-positive neurons in ventral mesencephalic grafts. Cell counts of subpopulations of TH-positive neurons also immunoreactive for aldehyde dehydrogenase 1-A1 (ALDH1) or calbindin, revealed improved survival of ALDH1/TH-positive neurons. However, the number of calbindin/TH-positive neurons was not affected. High density of dopamine-beta-hydroxylase (DBH)-positive innervation in the ventral mesencephalon placed adjacent to locus coeruleus was correlated to the improved survival. Ventral mesencephalic tissue, implanted at a distance to locus coeruleus, did not demonstrate improved survival, although DBH-positive nerve fibers were detected. In conclusion, the direct contact of locus coeruleus resulting in dense noradrenergic innervation of ventral mesencephalon is beneficial for the survival of ventral mesencephalic grafts. Thus, when trying to rescue dopamine neurons in Parkinson's disease, improving the noradrenergic input to the substantia nigra might be worth considering.

  • 11. Bruce, Lesley J
    et al.
    Ghosh, Sandip
    King, May Jean
    Layton, D Mark
    Mawby, William J
    Stewart, Gordon W
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Delaunay, Jean
    Tanner, Michael J A
    Absence of CD47 in protein 4.2-deficient hereditary spherocytosis in man: an interaction between the Rh complex and the band 3 complex.2002Inngår i: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 100, nr 5, 1878-1885 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present data on a patient of South Asian origin with recessive hereditary spherocytosis (HS) due to absence of protein 4.2 [4.2 (-) HS]. Protein 4.2 cDNA sequence analysis showed the presence of a novel 41-bp frameshift deletion that predicts a truncated peptide designated protein 4.2 Hammersmith. Quantitative reverse transcription-polymerase chain reaction indicated that the mutant mRNA was unstable. Sequencing of protein 4.2 genomic DNA revealed that the deletion stems from aberrant splicing. The proband was homozygous for a G>T substitution at position 1747 (cDNA numbering) that activates a cryptic acceptor splice site within exon 11 of the protein 4.2 gene (EPB42). The proband's mother was found to be heterozygous for this substitution. Unlike protein 4.2 null mice, the proband's red cells showed no evidence for abnormal cation permeability. Quantitation of red cell membrane proteins was carried out by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting, and flow cytometric measurement. CD47, a protein associated with the Rh complex, was markedly reduced to about 1% (in the proband) and 65% (in the mother) that found in healthy controls. The Rh-associated glycoprotein migrated with a higher than normal apparent molecular weight on SDS-PAGE. There was no obvious reduction in Rh polypeptides. These observations indicate that protein 4.2 and CD47 interact in the human red cell membrane. They provide further evidence for an association between the band 3 complex (band 3, ankyrin, protein 4.2, glycophorin A) and the Rh complex (Rh-associated glycoprotein, Rh polypeptides, glycophorin B, CD47, LW) and define a point of attachment between the Rh complex and the red cell cytoskeleton.

  • 12.
    Carlsöö, Bengt
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Studies on submandibular salivary gland peroxidase, its cellular localization and release mechanisms1974Doktoravhandling, med artikler (Annet vitenskapelig)
  • 13.
    Chermenina, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    GDNF and alpha-synuclein in nigrostriatal degeneration2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Parkinson’s disease is a common neurological disorder with a complex etiology. The disease is characterized by a progressive loss of dopaminergic cells in the substantia nigra, which leads to motor function and sometimes cognitive function disabilities. One of the pathological hallmarks in Parkinson’s disease is the cytoplasmic inclusions called Lewy bodies found in the dopamine neurons. The aggregated protein α-synuclein is a main component of Lewy bodies. In view of severe symptoms and the upcoming of problematic side effects that are developed by the current most commonly used treatment in Parkinson’s disease, new treatment strategies need to be elucidated. One such strategy is replacing the lost dopamine neurons with new dopamine-rich tissue. To improve survival of the implanted neurons, neurotrophic factors have been used. Glial cell line-derived neurotrophic factor (GDNF), which was discovered in 1993, improves survival of ventral mesencephalic dopamine neurons and enhances dopamine nerve fiber formation according to several studies. Thus, GDNF can be used to improve dopamine-rich graft outgrowth into the host brain as well as inducing sprouting from endogenous remaining nerve fibers. This study was performed on Gdnf gene-deleted mice to investigate the role of GDNF on the nigrostriatal dopamine system. The transplantation technique was used to create a nigrostriatal microcircuit from ventral mesencephalon (VM) and the lateral ganglionic eminence (LGE) from different Gdnf gene-deleted mice. The tissue was grafted into the lateral ventricle of wildtype mice. The results revealed that reduced concentrations of GDNF, as a consequence from the Gdnf gene deletion, had effects on survival of dopamine neurons and the dopamine innervation of the nigrostriatal microcircuit. All transplants had survived at 3 months independently of Gdnf genotype, however, the grafts derived from Gdnf gene-deleted tissue had died at 6 months. Transplants with partial Gdnf gene deletion survived up to 12 months after transplantation. Moreover, the dopaminergic innervation of striatal co-grafts was impaired in Gdnf gene-deleted tissue. These results highlight the role of GDNF for long-term maintenance of the nigrostriatal dopamine system. To further investigate the role of GDNF expression on survival and organization of the nigrostriatal dopamine system, VM and LGE as single or combined to double co-grafts created from mismatches in Gdnf genotypes were transplanted into the lateral ventricle of wildtype mice. Survival of the single grafts was monitored over one year using a 9.4T MR scanner. The size of single LGE transplants was significantly reduced by the lack of GDNF already at 2 weeks postgrafting while the size of single VM was maintained over time, independently of GDNF expression. The double grafts were evaluated at 2 months, and the results revealed that lack of GDNF in LGE reduced the dopamine cell survival, while no loss of dopamine neurons was found in VM single grafts. The dopaminergic innervation of LGE was affected by absence of GDNF, which also caused a disorganization of the striatal portion of the co-grafts. Small, cytoplasmic inclusions were frequently found in the dopamine neurons in grafts lacking GDNF expression. These inclusions were not possible to classify as Lewy bodies by immunohistochemistry and the presence of phospho-α-synuclein and ubiquitin; however, mitochondrial dysfunction could not be excluded. To further study the death of the dopamine neurons by the deprivation of GDNF, the attention was turned to how Lewy bodies are developed. With respect to the high levels of α-synuclein that was found in the striatum, this area was selected as a target to inject the small molecule – FN075, which stimulates α-synuclein aggregation, to further investigate the role of α-synuclein in the formation of cytoplasmic inclusions. The results revealed that cytoplasmic inclusions, similar to those found in the grafts, was present at 1 month after the injection, while impairment in sensorimotor function was exhibited, the number of dopamine neurons was not changed at 6 months after the injection. Injecting the templator to the substantia nigra, however, significantly reduced the number of TH-positive neurons at 3 months after injection. In conclusion, these studies elucidate the role of GDNF for maintenance and survival of the nigrostriatal dopamine system and mechanisms of dopamine cell death using small molecules that template the α-synuclein aggregation.

  • 14.
    Chermenina, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Chorell, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Henrik, Antti
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wittung-Stafshede, Pernilla
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    A novel animal model for Parkinson's disease based on in vivo effects of small-molecule of alpha-synucleinManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Amyloid fibrils of alpha-synuclein are major constituents of Lewy bodies, the pathological hallmark of Parkinson’s disease. Monomeric α-synuclein is involved in synaptic vesicle trafficking and long-term maintenance of neurons. The underlying mechanisms of Parkinson’s disease are not known but it has been proposed that oligomers of α-synuclein, formed during the aggregation process, are toxic to neurons. To search for a new animal model of Parkinson’s disease, here we capitalized on the in vitro discovery of a small-molecule templator of α-synuclein fibrillization, the 2-pyridone, FN075. FN075 and MS382, another 2-pyridone variant that act as an inhibitor of amyloids in vitro, were injected into the striatum or substantia nigra of normal C57Bl/6 mice. No acute toxicity of the compounds was detected, as there was 100 % survival of the injected mice. At 6 months after the striatal injection, sensorimotor functions were impaired with no reduction in TH-positive neurons in the substantia nigra in mice injected with FN075, whereas mice injected with MS382 or vehicle had no dysfunctions. Injection of FN075 into the substantia nigra revealed a significant loss of TH-positive neurons already at 3 months and TH-negative inclusion-like structures were detected in substantia nigra neurons of these mice. Thus, the results suggest that injection of a templator of α-synuclein aggregation into the brain of normal mice can serve as a novel experimental design for an animal model of Parkinson’s disease.

  • 15.
    Chermenina, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Schouten, P
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Nevalainen, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Johansson, F
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Orädd, Greger
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    GDNF is important for striatal organization and maintenance of dopamine neurons grown in the presence of the striatum2014Inngår i: Neuroscience, ISSN 0306-4522, E-ISSN 1873-7544, Vol. 270, 1-11 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Glial cell-derived neurotrophic factor (GDNF) exerts neuroprotective and neurorestorative effects on neurons and GDNF plays a significant role in maintenance of the dopamine neurons utilizing grafting to create a nigrostriatal microcircuit of Gdnf knockout (Gdnf(-/-)) tissue. To further evaluate the role of GDNF on organization of the nigrostriatal system, single or double grafts of ventral mesencephalon (VM) and lateral ganglionic eminence (LGE) with mismatches in Gdnf genotypes were performed. The survival of single grafts was monitored utilizing magnetic resonance imaging (MRI) and cell survival and graft organization were evaluated with immunohistochemistry. The results revealed that the size of VM single grafts did not change over time independent of genotype, while the size of the LGE transplants was significantly reduced already at 2weeks postgrafting when lacking GDNF. Lack of GDNF did not significantly affect the survival of tyrosine hydroxylase (TH)-positive neurons in single VM grafts. However, the survival of TH-positive neurons was significantly reduced in VM derived from Gdnf(+/+) when co-grafted with LGE from the Gdnf(-/-) tissue. In contrast, lack of GDNF in the VM portion of co-grafts had no effect on the survival of TH-positive neurons when co-grafted with LGE from Gdnf(+/+) mice. The TH-positive innervation of co-grafts was sparse when the striatal co-grafts were derived from the Gdnf(-/-) tissue while dense and patchy when innervating LGE producing GDNF. The TH-positive innervation overlapped with the organization of dopamine and cyclic AMP-regulated phosphoprotein-relative molecular mass 32,000 (DARPP-32)-positive neurons, that was disorganized in LGE lacking GDNF production. In conclusion, GDNF is important for a proper striatal organization and for survival of TH-positive neurons in the presence of the striatal tissue.

  • 16.
    Danielsson, Åke
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Functional aspects of the exocrine pancreas in relation to the islets of Langerhans: effects of islet hormones on the synthesis, storage and secretion of amylase1974Doktoravhandling, med artikler (Annet vitenskapelig)
  • 17.
    Domeij, Siw
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    The laryngeal mucosa and the superior laryngeal nerve of the rat: an immunohistochemical and electron microscopic study1990Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Neuropeptides are present in nerve fibers of the upper and lower airways. Local release of these substances may be of importance for the pathophysiology of airway disorders and may play a role in responses to different stimuli. However, little is known about the distribution of neuropeptides in the larynx. The superior laryngeal nerve is one of the vagal branches supplying the larynx. The aim of the present study was to investigate the fiber composition of this nerve and to analyse the distribution of different neuropeptides and mast cells in the larynx.

    The internal and the external branches of the superior laryngeal nerve had a similar number and size of the nerve fibers. Numerous unmyelinated fibers were evenly distributed in the branches. A large majority of the fibers were sensory myelinated and unmyelinated fibers; only a few of the myelinated fibers of the external branch ( 2-10 %) were motor. About a quarter of the unmyelinated fibers of the internal and the external branches had their cell bodies in the brainstem, and single myelinated and unmyelinated fibers emanated from the superior cervical ganglion. In every superior laryngeal nerve examined one to three spherical paraganglia were observed. These paraganglia contained cells which were similar to the type I and type II cells found in the carotid body and the paraganglia of the recurrent laryngeal nerve. Thin-walled sinusoidal blood vessels which were sometimes fenestrated were also present

    The laryngeal mucosa was supplied with nerve fibers exhibiting substance P- and calcitonin gene-related peptide-like immunoreactivity with regional differences in the distribution. The laryngeal side of the epiglottis and the ventral recess were richly supplied, and the vocal cords showed no evidence of immunoreactive nerve fibers. The distribution of connective tissue mast cells and mucosal mast cells/globular leucocytes was similar to that of nerve fibers displaying substance P- and calcitonin gene-related peptide-like immunoreactivity. These cells were found in close approximation to nerve fibers.

    Acetylcholinesterase-positive ganglionic cells in the larynx showed vasoactive intestinal polypeptide-, neuropeptide Y-and enkephalin-like immunoreactivity. Neuropeptide Y-like immunoreactivity was co-localized with tyrosine-hydroxylase/dopamine beta-hydroxylase-like immunoreactivity in nerve fibers in some blood vessel walls. Enkephalin-like immunoreactivity was rarely found in this location and co-localization with tyrosine- hydroxylase-like immunoreactivity was not detected. In glands and some blood vessel walls neuropeptide Y- and enkephalin-like immunoreactivity were localized in nerve fibers showing a positive acetylcholinesterase reaction and vasoactive intestinal polypeptide-like immunoreactivity. Thus, this indicates that neuropeptide Y is present in both the sympathetic and parasympathetic nervous systems, while enkephalin and vasoactive intestinal polypeptide are confined to the parasympathetic nervous system in the rat larynx.

    The present study shows that the superior laryngeal nerve is mainly sensory, and the study also provides a morphological basis for neuropeptide effects in laryngeal physiology/pathophysiology.

  • 18.
    Edin, Sofia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Wikberg, Maria L.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Dahlin, Anna M.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Rutegård, Jörgen
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Öberg, Åke
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Palmqvist, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    The Distribution of Macrophages with a M1 or M2 Phenotype in Relation to Prognosis and the Molecular Characteristics of Colorectal Cancer2012Inngår i: PLoS ONE, ISSN 1932-6203, Vol. 7, nr 10, e47045- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High macrophage infiltration has been correlated to improved survival in colorectal cancer (CRC). Tumor associated macrophages (TAMs) play complex roles in tumorigenesis since they are believed to hold both tumor preventing (M1 macrophages) and tumor promoting (M2 macrophages) activities. Here we have applied an immunohistochemical approach to determine the degree of infiltrating macrophages with a M1 or M2 phenotype in clinical specimens of CRC in relation to prognosis, both in CRC in general but also in subgroups of CRC defined by microsatellite instability (MSI) screening status and the CpG island methylator phenotype (CIMP). A total of 485 consecutive CRC specimens were stained for nitric oxide synthase 2 (NOS2) (also denoted iNOS) as a marker for the M1 macrophage phenotype and the scavenger receptor CD163 as a marker for the M2 macrophage phenotype. The average infiltration of NOS2 and CD163 expressing macrophages along the invasive tumor front was semi-quantitatively evaluated using a four-graded scale. Two subtypes of macrophages, displaying M1 (NOS2(+)) or M2 (CD163(+)) phenotypes, were recognized. We observed a significant correlation between the amount of NOS2(+) and CD163(+) cells (P<0.0001). A strong inverse correlation to tumor stage was found for both NOS2 (P<0.0001) and CD163 (P<0.0001) infiltration. Furthermore, patients harbouring tumors highly infiltrated by NOS2+ cells had a significantly better prognosis than those infiltrated by few NOS2+ cells, and this was found to be independent of MSI screening status and CIMP status. No significant difference was found on cancer-specific survival in groups of CRC with different NOS2/CD163 ratios. In conclusion, an increased infiltration of macrophages with a M1 phenotype at the tumor front is accompanied by a concomitant increase in macrophages with a M2 phenotype, and in a stage dependent manner correlated to a better prognosis in patients with CRC.

  • 19.
    Edin, Sofia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Wikberg, Maria L
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Palmqvist, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Macrophages: Good guys in colorectal cancer2013Inngår i: Oncoimmunology, ISSN 2162-4011, Vol. 2, nr 2, e23038- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Macrophages play a complex role in tumor progression since they can exert both tumor-preventing (M1 macrophages) and tumor-promoting (M2 macrophages) activities. In colorectal carcinoma (CRC), at odds to many other cancers, macrophage infiltration has been correlated with an improved patient survival. In a recent study, we have evaluated the distribution of M1 and M2 macrophage subtypes in CRC and their impact on patient prognosis.

  • 20.
    Edin, Sofia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Wikberg, Maria L
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Rutegård, Jörgen
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Palmqvist, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Phenotypic skewing of macrophages in vitro by secreted factors from colorectal cancer cells2013Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, nr 9, e74982- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Macrophages are cells with many important functions in both innate and adaptive immune responses and have been shown to play a complex role in tumor progression since they harbour both tumor preventing (M1 macrophages) and tumor promoting (M2 macrophages) activities. In many human cancers, infiltrating macrophages have been associated with a poor patient prognosis, and therefore suggested to be mainly of an M2 phenotype. However, we and others have previously shown that increased macrophage density in colorectal cancer (CRC) instead is correlated with an improved prognosis. It is an intriguing question if the different roles played by macrophages in various cancers could be explained by variations in the balance between M1 and M2 macrophage attributes, driven by tumor- or organ-specific factors in the tumor microenvironment of individual cancers. Here, we utilized an in vitro cell culture system of macrophage differentiation to compare differences and similarities in the phenotype (morphology, antigen-presentation, migration, endocytosis, and expression of cytokine and chemokine genes) between M1/M2 and tumor activated macrophages (TAMs), that could explain the positive role of macrophages in CRC. We found that secreted factors from CRC cells induced TAMs of a "mixed" M1/M2 phenotype, which in turn could contribute to a "good inflammatory response". This suggests that re-education of macrophages might allow for important therapeutic advances in the treatment of human cancer.

  • 21.
    Elmi, Adrian
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Idahl, Lars-Åke
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Sehlin, Janove
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Modulation of islet ATP content by inhibition or stimulation of the Na(+)/K(+) pump2001Inngår i: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 426, nr 1-2, 139-143 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High (30 mM) K(+), known to cause beta-cell membrane depolarisation, significantly decreased the islet total ATP content, supporting the view that beta-cell membrane depolarisation can activate the ATP-consuming Na(+)/K(+) pump. Ouabain (1 mM) did not change the islet ATP content after 5-15 min of incubation in the absence or presence of 3 mM glucose but reduced it after 30 min, and in the presence of 20 mM glucose, the reduction by ouabain occurred already after 15 min. Incubation of islets with ouabain for 60 min decreased the islet ATP content in the presence of 3, 10 or 20 mM glucose or 30 mM K(+). Also, the islet glucose oxidation rate was decreased by ouabain. When K(+) deficiency was used to inhibit the Na(+)/K(+) pump, no change in ATP content was observed irrespective of glucose concentration, although K(+) deficiency caused a slight inhibition of the glucose oxidation rate. Diazoxide reduced the islet glucose oxidation rate and increased the islet ATP content in the presence of 20 mM glucose. There may exist a feedback mechanism decreasing the flow of glucose metabolism in response to reduced ATP consumption by the Na(+)/K(+) pump.

  • 22.
    Fossati-Jimack, Liliane
    et al.
    University of Geneva.
    Azeredo da Silveira, Samareh
    University of Geneva.
    Moll, Thomas
    University of Geneva.
    Kina, Tatsuo
    Kyoto University.
    Kuypers, Frans A
    Children's Hospital Oakland Research Institute, Oakland, California.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Reininger, Luc
    Institut National de la Santé et de la Recherche Médicale U 399, Marseille.
    Izui, Shozo
    University of Geneva.
    Selective increase of autoimmune epitope expression on aged erythrocytes in mice: implications in anti-erythrocyte autoimmune responses2002Inngår i: Journal of Autoimmunity, ISSN 0896-8411, E-ISSN 1095-9157, Vol. 18, nr 1, 17-25 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the impact of changes occurring during red blood cell (RBC) ageing on the RBC-binding activity of pathogenic anti-erythrocyte monoclonal antibodies derived from autoimmune-prone New Zealand black (NZB) mice. As assessed by flow cytometric analysis on in vivo biotinylated RBCs, all five NZB-derived anti-RBC mAb exhibited more efficient binding to aged RBCs than to young RBCs, and resulted in a selective elimination of more aged RBCs from the circulating blood. In addition, treatment of RBCs with proteases markedly enhanced the binding of all five anti-RBC mAb, raising the possibility that increased exposure of autoimmune epitopes on aged RBCs may be in part, a result of contacts with proteolytic enzymes during the lifetime of circulating RBCs. In marked contrast, the binding activity of mAb raised in non-autoimmune animals against antigens expressed on RBCs, such as CD44, CD47, CD147 and TER-119, was either decreased or unchanged with RBC ageing, and these epitopes, except for that recognized by anti-CD47 mAb, were highly sensitive to mild treatment with proteases. Our data unravel the unique molecular feature of RBC epitopes involved in autoimmune haemolytic anaemia, suggesting that membrane alterations in aged RBCs might play a significant role in the development of the autoantibody response to RBCs.

  • 23.
    Franzén, Lars
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Sundström, Staffan
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Karlsson, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Gustafsson, Hans
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Öron- näs- och halssjukdomar.
    Littbrand, Bo
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Henriksson, Roger
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Fractionated irradiation and early changes in noradrenaline induced potassium efflux(86Rb+) in rat parotid gland1992Inngår i: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 31, nr 3, 359-364 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of fractionated irradiation on the electrolyte fluid secretion from rat parotid gland were studied. Secretion was measured as noradrenaline stimulated potassium efflux in vitro with Rb-86+ as tracer for potassium. The irradiation was delivered either as a five-day schedule (total dose 20, 25, 30, 35, 40, 45 Gy) or a two-day schedule (total dose 24, 32 Gy). The noradrenaline stimulated efflux was decreased in comparison with contralateral controls 10 days after the last irradiation. The effect was dose-dependent. Based on the data available, alpha/beta ratio of the used system was calculated to about 20 Gy, which corresponds to other results regarding early radiation effects.

  • 24. Gardai, Shyra J
    et al.
    McPhillips, Kathleen A
    Frasch, S Courtney
    Janssen, William J
    Starefeldt, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Murphy-Ullrich, Joanne E
    Bratton, Donna L
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Michalak, Marek
    Henson, Peter M
    Cell-surface calreticulin initiates clearance of viable or apoptotic cells through trans-activation of LRP on the phagocyte2005Inngår i: Cell, ISSN 0092-8674, E-ISSN 1097-4172, Vol. 123, nr 2, 321-334 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Apoptotic-cell removal is critical for development, tissue homeostasis, and resolution of inflammation. Although many candidate systems exist, only phosphatidylserine has been identified as a general recognition ligand on apoptotic cells. We demonstrate here that calreticulin acts as a second general recognition ligand by binding and activating LDL-receptor-related protein (LRP) on the engulfing cell. Since surface calreticulin is also found on viable cells, a mechanism preventing inadvertent uptake was sought. Disruption of interactions between CD47 (integrin-associated protein) on the target cell and SIRPalpha (SHPS-1), a heavily glycosylated transmembrane protein on the engulfing cell, permitted uptake of viable cells in a calreticulin/LRP-dependent manner. On apoptotic cells, CD47 was altered and/or lost and no longer activated SIRPalpha. These changes on the apoptotic cell create an environment where "don't eat me" signals are rendered inactive and "eat me" signals, including calreticulin and phosphatidylserine, congregate together and signal for removal.

  • 25.
    Gitik, Miri
    et al.
    Hebrew University Hadassah Medical School, Jerusalem.
    Liraz Zaltsman, Sigal
    Hebrew University Hadassah Medical School, Jerusalem.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Reichert, Fanny
    Hebrew University Hadassah Medical School, Jerusalem.
    Rotshenker, Shlomo
    Hebrew University Hadassah Medical School, Jerusalem.
    Myelin down-regulates myelin phagocytosis by microglia and macrophages through interactions between CD47 on myelin and SIRPalpha (signal regulatory protein-alpha) on phagocytes2011Inngår i: Journal of Neuroinflammation, ISSN 1742-2094, Vol. 8, nr 1, 24- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Traumatic injury to axons produces breakdown of axons and myelin at the site of the lesion and then further distal to this where Wallerian degeneration develops. The rapid removal of degenerated myelin by phagocytosis is advantageous for repair since molecules in myelin impede regeneration of severed axons. Thus, revealing mechanisms that regulate myelin phagocytosis by macrophages and microglia is important. We hypothesize that myelin regulates its own phagocytosis by simultaneous activation and down-regulation of microglial and macrophage responses. Activation follows myelin binding to receptors that mediate its phagocytosis (e.g. complement receptor-3), which has been previously studied. Down-regulation, which we test here, follows binding of myelin CD47 to the immune inhibitory receptor SIRPalpha (signal regulatory protein-alpha) on macrophages and microglia.

    METHODS: CD47 and SIRPalpha expression was studied by confocal immunofluorescence microscopy, and myelin phagocytosis by ELISA.

    RESULTS: We first document that myelin, oligodendrocytes and Schwann cells express CD47 without SIRPalpha and further confirm that microglia and macrophages express both CD47 and SIRPalpha. Thus, CD47 on myelin can bind to and subsequently activate SIRPalpha on phagocytes, a prerequisite for CD47/SIRPalpha-dependent down-regulation of CD47+/+ myelin phagocytosis by itself. We then demonstrate that phagocytosis of CD47+/+ myelin is augmented when binding between myelin CD47 and SIRPalpha on phagocytes is blocked by mAbs against CD47 and SIRPalpha, indicating that down-regulation of phagocytosis indeed depends on CD47-SIRPalpha binding. Further, phagocytosis in serum-free medium of CD47+/+ myelin is augmented after knocking down SIRPalpha levels (SIRPalpha-KD) in phagocytes by lentiviral infection with SIRPalpha-shRNA, whereas phagocytosis of myelin that lacks CD47 (CD47-/-) is not. Thus, myelin CD47 produces SIRPalpha-dependent down-regulation of CD47+/+ myelin phagocytosis in phagocytes. Unexpectedly, phagocytosis of CD47-/- myelin by SIRPalpha-KD phagocytes, which is not altered from normal when tested in serum-free medium, is augmented when serum is present. Therefore, both myelin CD47 and serum may each promote SIRPalpha-dependent down-regulation of myelin phagocytosis irrespective of the other.

    CONCLUSIONS: Myelin down-regulates its own phagocytosis through CD47-SIRPalpha interactions. It may further be argued that CD47 functions normally as a marker of "self" that helps protect intact myelin and myelin-forming oligodendrocytes and Schwann cells from activated microglia and macrophages. However, the very same mechanism that impedes phagocytosis may turn disadvantageous when rapid clearance of degenerated myelin is helpful.

  • 26.
    Grankvist, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Mechanisms of alloxan diabetogenicity1981Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Suspensions of pancreatic islet cells from ob/ob-mice were incubated with Trypan Blue. Microscope photometry showed that apparently viable cells excluded the dye completely, whereas the nuclei of non-viable cells accumulated Trypan Blue by a saturable process. Alloxan rapidly increased the permeability of the plasma membrane in mouse 3-cells; the exclusion of Trypan Blue is a valid and useful measure of islet cell viability following alloxan exposure.

    The diabetogenic action of alloxan may be mediated by hydroxyl radicals. In several biological systems hydroxyl radicals are formed by an iron-catalyzed reaction between superoxide anion radicals and hydrogen peroxide. To test whether this applies to alloxan diabetogenicity, the effects of superoxide dismutase, catalase, scavengers of hydroxyl radicals, and metal ion chelators were tested (a) in a cell-free radical-generating system and (b) on islets and islet-cells exposed to alloxan In vitro. The effect of longtime-circulating superoxide dismutase injected prior to alloxan was tested on mice in vivo.

    Luminol chemiluminescence was used to monitor alloxan-dependent radical production. Accumulation of 8^Rb+ and exclusion of Trypan Blue were used as cell viability criteria in isolated mouse islets and islet-cells. Blood glucose was determined to monitor the development of diabetes in living animals.

    Superoxide dismutase, catalase, scavengers of hydroxyl radicals, and metal ion chelators inhibited the alloxan-dependent chemiluminescence and decreased the toxic effects on Rb+ accumulation or Trypan Blue exclusion in islets and islet-cells. Superoxide dismutase, linked to polyethylene glycol and injected 12 hours before alloxan, largely prevented the development of alloxan diabetes.

    Alloxan toxicity _in vitro and in vivo seems to depend on the formation of superoxide radicals and hydrogen peroxide which in turn form the noxious hydroxyl radical via an iron-catalyzed Haber-Weiss reaction.

    As free radicals and hydrogen peroxide can be formed by other chemicals and during inflammation, and inflammation may accompany the outbreak of human diabetes, studies on the beneficiary effects of superoxide dismutase and other scavengers of free radicals in other forms of diabetes seem warranted.

  • 27.
    Gustafsson, Hans
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Öron- näs- och halssjukdomar.
    Salivary gland neoplasms: studies on the cytoskeleton, the secretory apparatus and the nuclear DNA content1986Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The heterogeneity of salivary gland neoplasms have made classification and prognostication of these tumours sometimes difficult, and the in­troduction of techniques, such as enzyme and carbohydrate histochemis­try and electron microscopy have only to a certain extent increased our knowledge in these respects. In the present study immunohistochemical methods have been used to identify intermediate filament proteins (IFP) in normal fetal and adult parotid glands, as well as in salivary neo­plasms. The intermediate filaments (IF) make up the cytoskeleton in eucaryotic cells. Epithelial tissue contains IF composed of different cytokeratins (CK 1-19) whilst mesenchymal tissue generally contains IF composed of vimentin, and the IFP pattern is very stable even during cell transformation. It would thus be possible to further clarify the histogenesis of salivary neoplasms by identifying IFP, in addition the IFP pattern would probably be useful in tumour typing. Furthermore, ultrastructural cytochemical studies, microspectorphotometry on nuclear DNA as well as enzyme secretory studies of certain tumour types were carried out, in order to further characterize the biology of salivary neoplasms.

    The immunohistochemical investigations showed that in normal parotid tissue, the different cell types differed in IFP expression: acinar cells express mainly CK 18 and myoepithelial cells mainly CK 17 and 19, whilst duct cells contained a broad range of CK. Vimentin could in ad­dition to CK be detected in myoepithelial cells and basal cells of ex­cretory ducts. Fetal parotid cells showed a similar CK pattern as mature duct cells. In addition, vimentin could be found in some basal cells of the terminal tubules of the fetal glands. Salivary neoplasms could be divided into three types with regard to their IFP pattern:

    1.  Acinic cell carcinomas showed a CK-pattern similar to normal acinar cells but a co-expression of CK and vimentin was present in some cells.
    2.  Adenoid cystic carcinomas, mixed tumours and basal cell adenomas showed a CK-pattern of normal duct or myoepithelial cells. The peri­pheral cells were also vimentin positive. 3. Mucoepidermoid carcinomas and adenocarcinomas had a similar CK-pattern as duct cells, and no tu­mour cells contained vimentin. This indicates that typing of IFP may be useful for subgrouping of salivary neoplasms.

    By stereological measurements, the cells of acinic cell carcinomas were found to be very similar to normal parotid acinar cells. Furthermore, they contained amylase and after stimulation by norepiphrine a secre­tory response was induced, with a rise in intracellular cAMP as well as a release of amylase. By single cell measurements of nuclear DNA con­tent, no difference was found between acinic cell carcinomas with de­finite metastasis and those without recurrence, both in paraffin sec­tions and cytological smears.

  • 28.
    Gustavsson, Natalia
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Cell-Specific Ca2+ Response in Pancreatic ß-cells2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Pancreatic ß-cells are heterogeneous in their secretory responsiveness, glucose sensitivity and metabolic rate. A diminished and delayed first-phase insulin release is an early sign of failing ß-cells in diabetes. Mechanisms controlling functional characteristics, such as lag time for insulin release or magnitude of the response in each individual cell are unknown. To find out whether the heterogeneity represents a random phenomenon in ß-cell or is a manifestation of reproducible characteristics, we compared parameters of Ca2+ response in Fura-2 labelled ob/ob mouse ß-cells during two consecutive stimulations with glucose. Lag times, as well as peak heights and nadirs of initial lowering showed a strong correlation between the first and second stimulation. Thus, timing and magnitude of the early Ca2+ response were specific for each cell. ß-Cells from lean mice, diabetic db/db mice and rats also showed cell-specific responses characteristics. This indicates that a cell-specific Ca2+ response to glucose is common in rodent ß-cells, both normal and diabetic. Another question was whether aggregated ß-cells show cell-specific responses. Using the same protocol as for dispersed ß-cells, we analysed Ca2+ responses in clusters of different size and in intact islets from ob/ob and lean mice. Correlations were found between the first and second stimulation for timing and magnitude of [Ca2+]i rise, and for the initial lowering.

    Next, we tested if the ß-cell response is cell-specific, when induced at different steps of the stimulus-secretion coupling. The glycolytic intermediate glyceraldehyde, the mitochondrial substrate KIC, the KATP-channel blocker tolbutamide and arginine were used as tools. [Ca2+]i changes were studied in dispersed ß-cells from lean, ob/ob and db/db mice. NADH responses to glucose and KIC were analyzed as a measure of metabolic flux. The correlation between Ca2+ and insulin response from individual ß-cells was tested using Fluo-3 and Fluozin-3.

    Both timing and magnitude of calcium responses were cell-specific in lean mouse ß-cells with all tested secretagogues. ß-Cells from ob/ob and db/db mice showed cell-specific timing of Ca2+ responses to glyceraldehyde but not to KIC, tolbutamide or arginine. However, ob/ob mouse ß-cells within intact islets showed cell-specific timing of tolbutamide-induced response. NADH responses to glucose were cell-specific in all three mouse models, but the timing of NADH responses to KIC was cell-specific only in lean mice. Thus, a cell-specific response can be induced in normal ß-cells at several steps of stimulus-secretion coupling for nutrient-stimulated insulin release. Cell-specific properties of ß-cell ion channels and the mitochondrial metabolism are affected in db/db and ob/ob mice.

    The relation between mitochondrial mass and parameters of Ca2+ responses were investigated in Mitotracker Red and Fluo-3 labelled ß-cells using confocal microscopy. Data show that ß-cell mitochondrial state may play an important role in determining the timing of [Ca2+]i changes.

    In summary, the early Ca2+ response pattern in ß-cells, including the lag time, the nadir of initial lowering and the height of the first peak response is cell-specific. Isolated and functionally coupled ß-cells show cell-specific timing of Ca2+ responses when stimulated with metabolic and non-metabolic agents. This may be a robust mechanism of importance for the adequate function of ß-cells and a basis for the pacemaker function of some cells. A disturbed cell specificity of the mitochondrial metabolism and ion channel function appears to be a marker of ß-cell dysfunction in hyperglycemia and diabetes and may explain the delayed insulin release in ß-cells from diabetic subjects.

  • 29.
    Gustavsson, Natalia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Abedi, Golbarg
    Larsson-Nyrén, Gerd
    Lindström, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Timing of Ca2+ response in pancreatic ß-cells is related to mitochondrial massManuskript (Annet vitenskapelig)
  • 30.
    Gustavsson, Natalia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Larsson-Nyrén, Gerd
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Lindström, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Pancreatic beta cells from db/db mice show cell-specific [Ca2+]i and NADH responses to glucose but not to alpha-ketoisocaproic acid.2005Inngår i: Pancreas, ISSN 0885-3177, E-ISSN 1536-4828, Vol. 31, nr 3, 242-250 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: We recently showed that timing and magnitude of the glucose-induced cytoplasmic calcium [Ca2+]i response are reproducible and specific for the individual beta cell. We now wanted to identify which step(s) of stimulus-secretion coupling determine the cell specificity of the [Ca2+]i response and whether cell specificity is lost in beta-cells from diabetic animals. Besides glucose, we studied the effects of glyceraldehyde, a glycolytic intermediate, and alpha-ketoisocaproic acid (KIC), a mitochondrial substrate. METHODS: Early [Ca2+]i changes were studied stimulations in fura-2-labeled dispersed beta cells from lean, ob/ob, and db/db mice. Lag time and peak height were compared during 2 consecutive stimulations with the same stimulator. Nicotinamide adenine dinucleotide (NADH) responses to glucose and KIC were studied as a measure of metabolic flux. RESULTS: Both glyceraldehyde and KIC induced cell-specific temporal responses in lean mouse beta cells with a correlation between lag times for [Ca2+]i rise during the first and second stimulation. Beta cells from ob/ob and db/db mice showed cell-specific temporal [Ca2+]i responses to glucose and glyceraldehyde but not to KIC. Glucose induced cell-specific NADH responses in all 3 models, but KIC did so only in lean mouse [beta] cells. CONCLUSIONS: A cell-specific response may be induced at several steps of beta-cell stimulus-secretion coupling. Mitochondrial metabolism generates a cell-specific response in normal beta cells but not in db/db and ob/ob mouse beta cells.

  • 31.
    Gylfe, Erik
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Studies on free amino acids in the pancreatic β-cells.1974Doktoravhandling, med artikler (Annet vitenskapelig)
  • 32.
    Hagnerud, Sven
    et al.
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Manna, Partha Pratim
    Cella, Marina
    Stenberg, Åsa
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Frazier, William A
    Colonna, Marco
    Oldenborg, Per-Arne
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Deficit of CD47 results in a defect of marginal zone dendritic cells, blunted immune response to particulate antigen and impairment of skin dendritic cell migration.2006Inngår i: Journal of Immunology, ISSN 0022-1767, Vol. 176, nr 10, 5772-8 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CD47 is a ubiquitously expressed cell surface glycoprotein that associates with integrins and regulates chemotaxis, migration, and activation of leukocytes. CD47 is also a ligand for signal regulatory protein alpha, a cell surface receptor expressed on monocytes, macrophages, granulocytes, and dendritic cell (DC) subsets that regulates cell activation, adhesion, and migration. Although the function of CD47 in macrophages and granulocytes has been studied in detail, little is known about the role of CD47 in DC biology in vivo. In this study we demonstrate that CD47(-/-) mice exhibit a selective reduction of splenic CD11c(high)CD11b(high)CD8alpha(-)CD4(+) DCs. These DCs correspond to marginal zone DCs and express signal regulatory protein alpha, possibly explaining their selective deficiency in CD47(-/-) mice. Deficiency of marginal zone DCs resulted in impairment of IgG responses to corpusculate T cell-independent Ags. Although epidermal DCs were present in normal numbers in CD47(-/-) mice, their migration to draining lymph nodes in response to contact sensitization was impaired, while their maturation was intact. In vitro, CD47(-/-) mature DCs showed normal CCR7 expression but impaired migration to CCL-19, whereas immature DC response to CCL-5 was only slightly impaired. These results demonstrate a fundamental role of CD47 in DC migration in vivo and in vitro and in the function of marginal zone DCs.

  • 33. Hansson, A C
    et al.
    Sommer, W H
    Metsis, M
    Strömberg, Ingrid
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Agnati, L F
    Fuxe, K
    Corticosterone actions on the hippocampal brain-derived neurotrophic factor expression are mediated by exon IV promoter.2006Inngår i: Journal of neuroendocrinology (Print), ISSN 0953-8194, Vol. 18, nr 2, 104-114 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Brain-derived neurotrophic factor (BDNF) expression is strongly regulated by adrenocorticosteroids via activated gluco- and mineralocorticoid receptors. Four separate promoters are located upstream of the BDNF noncoding exons I to IV and may thus be involved in adrenocorticosteroid-mediated gene regulation. In adrenalectomised rats, corticosterone (10 mg/kg s.c.) induces a robust down-regulation of both BDNF mRNA and protein levels in the hippocampus peaking at 2-8 h. To study the role of the individual promoters in the corticosterone response, we employed exon-specific riboprobe in situ hybridisation as well as real-time polymerase chain reaction (PCR) in the dentate gyrus. We found a down-regulation, mainly of exon IV and the protein-coding exon V, in nearby all hippocampal subregions, but exon II was only down-regulated in the dentate gyrus. Exon I and exon III transcripts were not affected by corticosterone treatment. The results could be confirmed with real-time PCR in the dentate gyrus. It appears as if the exon IV promoter is the major target for corticosterone-mediated transcriptional regulation of BDNF in the hippocampus.

  • 34.
    Hashemian, Sanazalsadat
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Interaction between nerve fiber formation and astrocytes2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Parkinson’s disease, the second most common neurodegenerative disorder,is characterized by loss of nigrostriatal dopaminergic neurons. To date,there is no defined cause and cure for the disease. An ideal treatmentstrategy is to replace the lost neurons by transplanting fetal dopaminergicneurons to the brain of parkinsonian patients. Clinical trials have beenperformed and the outcome was variable where one significant obstaclewas the limited graft reinnervation of the host brain. To study this issue,organotypic tissue culture can be utilized to monitor dopaminergic nervefiber outgrowth in vitro and their association with astrocytes. Using thisculture technique, dopaminergic nerve fibers appear in twomorphologically and temporally different types. The early appearing nervefibers are formed in the absence of astrocytes, reach long distances, andare called non-glial-associated tyrosine hydroxylase (TH) -positive nervefibers. After a few days, the second sequence of nerve fibers, the glialassociatedTH-positive nerve fibers, are formed, and their growth arelimited to the presence of astrocytes, that migrate and form a monolayersurrounding the plated tissue. The aim of this thesis was to study theinteraction between nerve fiber formation and astrocytes with a specialfocus on the long-distance growing nerve fibers. Ventral mesencephalic(VM) organotypic slice cultures from embryonic day (E) 12, E14, and E18were incubated for 14, 21, 28, and 35 days in vitro (DIV). The resultsrevealed that the two morphologically different processes were found incultures from the younger stages, while no non-glial-associated growthwas found in cultures of tissue from E18. Instead neurons had migratedonto the migrating astrocytes. Astrocytes migrated longer distances intissue from older stages, and the migration reached a plateau at 21 DIV.Co-cultures of E14 VM tissue pieces and cell suspension of matureastrocytes promoted migration of neurons, as seen in E18 cultures. Thus,9the maturity of the astrocytes was an important factor for nerve fiberoutgrowth. Hence, targeting molecules secreted by astrocytes might bebeneficial for regeneration. Chondroitin sulfate proteoglycan (CSPG), amember of proteoglycan family, is produced by the astrocytes and has adual role of being permissive during development and inhibitory afterbrain injury in adult brain. Cultures were treated with chondroitinase ABC(ChABC) or methyl-umbelliferyl-β-D-xyloside (β-xyloside) in twodifferent protocols, early and late treatments. The results from the earlytreated cultures showed that both compounds inhibited the outgrowth ofnerve fibers and astrocytic migration in cultures from E14 tissue, while β-xyloside but not ChABC promoted the non-glial-associated growth incultures derived from E18 fetuses. In addition, β-xyloside but not ChABCinhibited neuronal migration in E18 cultures. Taken together, β-xylosideappeared more effective than ChABC in promoting nerve fiber growth.Another potential candidate, integrin-associated protein CD47, was studiedbecause of its role in synaptogenesis, which is important for nerve fibergrowth. Cultures from E14 CD47 knockout (CD47-/-) mice were plated andcompared to their wildtypes. CD47-/- cultures displayed a massive and longnon-glial-associated TH-positive nerve fiber outgrowth despite theirnormal astrocytic migration. Blocking either signal regulatory protein-α(SIRPα) or thrombospondin-1 (TSP-1), which bind to CD47, had nogrowth promoting effect. In conclusion, to promote nerve growth, youngertissue can grow for longer distances than older tissue, and inhibiting CSPGproduction promotes nerve growth in older tissue, while gene deletion ofCD47 makes the astrocytes permissive for a robust nerve fiber growth.

  • 35.
    Henriksson, Maria L
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Edin, Sofia
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Dahlin, Anna M
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Öberg, Åke
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Van Guelpen, Bethany
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Rutegård, Jörgen
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Stenling, Roger
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Palmqvist, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Colorectal Cancer Cells Activate Adjacent Fibroblasts Resulting in FGF1/FGFR3 Signaling and Increased Invasion.2011Inngår i: American Journal of Pathology, ISSN 0002-9440, E-ISSN 1525-2191, Vol. 178, nr 3, 1387-1394 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cancer-associated fibroblasts expressing fibroblast activation protein (FAP) have been implicated in the invasive behavior of colorectal cancer. In this study, we use FAP expression as a marker of fibroblast activation and analyze the effect of activated fibroblasts on colorectal cancer migration and invasion in experimental cell studies. We also investigated the expression pattern of FAP in cancer-associated fibroblasts during transformation from benign to malignant colorectal tumors. In immunohistochemical analyses, FAP was expressed in fibroblasts in all colorectal cancer samples examined, whereas all normal colon, hyperplastic polyps, or adenoma samples were negative. In in vitro studies, conditioned medium from colon cancer cells, but not adenoma cells, activated fibroblasts by inducing FAP expression. These activated fibroblasts increased the migration and invasion of colon cancer cells in Boyden chamber experiments and in a three-dimensional cell culture model. We identify fibroblast growth factor 1/fibroblast growth factor receptor 3 (FGF1/FGFR-3) signaling as mediators leading to the increased migration and invasion. Activated fibroblasts increase their expression of FGF1, and by adding a fibroblast growth factor receptor inhibitor, as well as an FGF1-neutralizing antibody, we reduced the migration of colon cancer cells. Our findings provide evidence of a possible molecular mechanism involved in the cross talk between cancer cells and fibroblasts leading to cancer cell invasion.

  • 36.
    Henriksson, Roger
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Modulation of serous salivary gland function by the sympathetic nervous system: a biochemical and ultrastructural study with special reference to β-adrenoceptor subtypes1981Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The aim of the present investigation was to study the influence of the sympathetic nervous system and of various adrenoceptor agents on enzyme secretion and morphology in rat parotid and guinea-pig submandibular glands. Biochemical methods were combined with electron microscopical techniques.

    Two different in vitro systems were employed, batch-incubation and microperifusion, to characterize the sympathetically evoked amylase release and its correlation to cyclic AMP. By using various selective β-adrenoceptor agonists and antagonists a dominance of the β1-adrenoceptor over the β2 - in regulating amylase release - was establ ished. Continuous noradrenaline perifusion caused a rapid initial amylase discharge, closely correlated to tissue levels of cyclic AMP; no correlation between the two was observed during the later phase. Prenalterol (a β1-agonist) failed to elevate glandular cyclic AMP. This was in contrast to its potent secretagogic effect. On the other hand, terbutaline (a β2-agonist) was a weak secretagogue but markedly raised the levels of cyclic AMP. Thus, β-adrenoceptor activation may lead to release of large amounts of amylase despite minimal or no increase in cyclic AMP. Moreover, these effects seemed to be dissociated in salivary glands with regard to the β-adrenoceptor subtypes. This was further substantiated by the findings that repeated injections of prenalterol induced qualitative changes in the granule populations, similar to those caused by the non-selective β-agonist isoprenaline. Terbutaline was without effect. However, acinar cells size was increased following both prenalterol and terbutaline treatment. The data suggest that the 3-adrenergic effects on acinar cell size and granule population may be independently regulated.

    A decreased sympathetic activity of long duration was induced by neonatal or adult extirpation of the superior cervical ganlion on one side. Acinar cell size, as well as granule and amylase content was reduced 9 weeks after neonatal denervation. Ganglionectomy performed in adult animals was without significant effects.

    The secretory behaviour of neonatally denervated glands was characterized by an increased postjunctional sensitivity to 3-adrenoceptor agonists. Of special interest was the finding that neonatal denervation seemed to transform terbutaline from a partial to a full secretory agonist, thus changing its effects in the direction of those of prenalterol and noradrenaline. Moreover, increased levels of cyclic AMP as well as an enhanced response to DBcAMP were noted in the denervated glands as were intracellular changes. The denervation supersensitivity after neonatal denervation seems to differ from that observed in adult denervated glands. The results of the studies on denervated glands suggest that the sympathetic nervous system plays a fundamental role in the early maturation of the rat parotid gland as well as for the development of the β-adrenoceptor subtypes.

  • 37.
    Hult, Andreas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Malm, Christer
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Transfusion of cryopreserved human red blood cells into healthy humans is associated with rapid extravascular hemolysis without a proinflammatory cytokine response2013Inngår i: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 53, nr 1, 28-33 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Transfusion of stored red blood cells (RBCs) can be associated with adverse side effects. Recent studies in mice transfused with stored RBCs showed that a strong proinflammatory cytokine storm was induced due to extravascular hemolysis already at 2 hours after transfusion. Therefore, we here investigated if transfusion of 2 units of cryopreserved autologous RBCs induced a proinflammatory response in healthy human volunteers.

    STUDY DESIGN AND METHODS: Two units of autologous RBCs, cryopreserved for 16 weeks, were transfused into 10 healthy human volunteers. Serum and blood samples taken at 2 hours before and at 2 and 48 hours after transfusion were analyzed for signs of extravascular hemolysis and the presence of proinflammatory cytokines.

    RESULTS: At 2 hours after transfusion, transferin-bound serum iron, as well as transferin saturation and total bilirubin, were already significantly increased. These measures all returned back toward that in pretransfusion samples at 48 hours after transfusion. No increases in the production of the proinflammatory cytokines interleukin (IL)-1β, IL-6, IL-8, monocyte chemotactic protein-1, macrophage inflammatory protein-1β, or tumor necrosis factor-α were detected at any time point after transfusion.

    CONCLUSION: Although a significant level of extravascular hemolysis already occurred at 2 hours after transfusion of cryopreserved RBCs, there were no signs of proinflammatory cytokine production up to 48 hours after transfusion.

  • 38. Ikeda, Hiroshi
    et al.
    Okazawa, Hideki
    Ohnishi, Hiroshi
    Murata, Yoji
    Oldenborg, Per-Arne
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Histologi med cellbiologi.
    Matozaki, Takashi
    Mutational analysis of the mechanism of negative regulation by SRC homology 2 domain-containing protein tyrosine phosphatase substrate-1 of phagocytosis in macrophages.2006Inngår i: Journal of Immunology, ISSN 0022-1767, Vol. 177, nr 5, 3123-32 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Src homology 2 domain-containing protein tyrosine phosphatase substrate-1 (SHPS-1) is a transmembrane protein predominantly expressed in macrophages. The binding of CD47 on RBCs to SHPS-1 on macrophages is implicated in inhibition of phagocytosis of the former cells by the latter. We have now shown that forced expression in mouse RAW264.7 macrophages of a mutant version (SHPS-1-4F) of mouse SHPS-1, in which four tyrosine phosphorylation sites are replaced by phenylalanine, markedly promoted Fc gammaR-mediated phagocytosis of mouse RBCs or SRBCs. Forced expression of another mutant form (SHPS-1-deltaCyto) of mouse SHPS-1, which lacks most of the cytoplasmic region, did not promote such phagocytosis. Similarly, forced expression of a rat version of SHPS-1-4F, but not that of rat wild-type SHPS-1 or SHPS-1-deltaCyto, in RAW264.7 cells enhanced Fc gammaR-mediated phagocytosis of RBCs. Tyrosine phosphorylation of endogenous SHPS-1 as well as its association with Src homology 2 domain-containing protein tyrosine phosphatase-1 were not markedly inhibited by expression of SHPS-1-4F. Furthermore, the attachment of IgG-opsonized RBCs to RAW264.7 cells was markedly increased by expression of SHPS-1-4F, and this effect did not appear to be mediated by the interaction between CD47 and SHPS-1. These data suggest that inhibition by SHPS-1 of phagocytosis in macrophages is mediated, at least in part, in a manner independent of the transinteraction between CD47 and SHPS-1. In addition, the cytoplasmic region as well as tyrosine phosphorylation sites in this region of SHPS-1 appear indispensable for this inhibitory action of SHPS-1. Moreover, SHPS-1 may regulate the attachment of RBCs to macrophages by an as yet unidentified mechanism.

  • 39.
    Ingvarsson, Magdalena
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Obstetrik och gynekologi.
    Höckenström, T
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Lindgren, P
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Obstetrik och gynekologi.
    Ridderheim, M
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bäckström, Torbjörn
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Obstetrik och gynekologi.
    Isolation and culture of ovarian tumour cells, cytological and cell survival evaluation1999Inngår i: Anticancer Research, ISSN 0250-7005, Vol. 19, nr 6B, 5069-5073 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this study was to evaluate the reproducibility and reliability of the fluorometric microculture cytotoxicity assay (FMCA). Emphasis was placed on obtaining pure tumour cell cultures which were subjected to careful cytological evaluation. Preparations of 39 ovarian tumours, malignant, borderline and benign were made, of which 37 were successfully cultured. In 34 of the 37 tumour cell cultures, the epithelial cell fraction was > 90%, and in 30 of 39 cultures the epithelial cell fraction was > 95%. Transportation within 24 h and the 72 h incubation did not change the yield or epithelial cell fraction. There was a linear relationship between fluorescence and the number of viable cells. The fluorescence increased with time, making only comparisons within each assay plate possible. The sensitivity of the method makes it possible to perform many analyses on a small amount of material. The method also makes it possible to study cells derived from all stages of the disease, including benign tumours.

  • 40.
    Ishikawa-Sekigami, Tomomi
    et al.
    Gunma University.
    Kaneko, Yoriaki
    Gunma University.
    Saito, Yasuyuki
    Gunma University.
    Murata, Yoji
    Gunma University.
    Okazawa, Hideki
    Gunma University.
    Ohnishi, Hiroshi
    Gunma University.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Nojima, Yoshihisa
    Gunma University.
    Matozaki, Takashi
    Gunma University.
    Enhanced phagocytosis of CD47-deficient red blood cells by splenic macrophages requires SHPS-1.2006Inngår i: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 343, nr 4, 1197-200 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The interaction of CD47 on red blood cells (RBCs) with SHPS-1 on macrophages is implicated to prevent the phagocytosis of the former cells by the latter cells. Indeed, the rate of clearance of transfused CD47-deficient (CD47(-/-)) RBCs from the bloodstream of wild-type mice was markedly increased compared with wild-type RBCs. Conversely, the rate of clearance of transfused wild-type RBCs was markedly increased in mice that expressed a mutant form of SHPS-1 lacking most of the cytoplasmic region of the protein. However, we here found that the clearance of CD47(-/-) RBCs in SHPS-1 mutant mice was minimal. In addition, the phagocytosis of CD47(-/-) RBCs by splenic macrophages from SHPS-1 mutant mice was markedly reduced compared with wild-type macrophages. These results thus suggest an additional role for CD47 on RBCs in the negative regulation of phagocytosis by macrophages and in determination of the life span of circulating RBCs.

  • 41.
    Johansson, Johanna
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi. Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik. Masterprogrammet i biomedicin.
    The cell-surface flycoprotein CD47 regulates apoptosis in murine neutrophils2014Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
  • 42.
    Koskinen, Cecilia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Engman, Sara
    Sulniute, Rima
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Matozaki, Takashi
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Lundberg, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Reduced SIRPα phosphorylation and concommitant SHP-2–PI3K–Akt2 signaling decrease osteoblast differentiationArtikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Normal differentiation of bone forming osteoblasts is a prerequisite for maintenance of skeletal health and is dependent on an intricate cellular signaling including the essential transcription factor Runx2. The cell surface glycoprotein CD47 and its receptor signal regulatory protein alpha (SIRPα) are suggested to regulate bone cell differentiation. In the present study, we investigated osteoblastic differentiation of bone marrow stromal cells from SIRPα mutant mice lacking the cytoplasmic signaling domain of SIRPα. Moreover, we compared downstream signaling events of SIRPα in wild-type and CD47-deficient mouse bone marrow stromal cells. SIRPα-mutant stromal cells showed significantly less expression of Runx2, Sp7 (osterix), Bglap (osteocalcin), and Akp1 (alkaline phosphatase) mRNA compared to stromal cells from wild-type mice. An impaired osteoblastogenesis in SIRPα-mutant cell cultures was demonstrated by lower alkaline phosphatase activity and less mineral formation compared to wild-type cultures. Western blot analyses showed that CD47 expression was required for Src homology-2 domain containing protein tyrosine phosphatase- 2 (SHP-2) to associate with SIRPa. As a result, SHP-2 and Akt2 in stromal cells from CD47 deficient mice were less phosphorylated, as compared to that in wild-type stromal cells. In conclusion, we here show that CD47-dependent SIRPα signaling through SHP-2–PI3K–Akt2 strongly influences osteogenic differentiation of bone marrow stromal cells.

  • 43.
    Koskinen, Cecilia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Persson, Emelie
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Baldock, Paul
    Stenberg, Åsa
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Boström, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Matozaki, Takashi
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Lundberg, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Lack of CD47 impairs bone cell differentiation and results in an osteopenic phenotype in vivo due to impaired signal regulatory protein α (SIRPα) signaling2013Inngår i: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 288, nr 41, 29333-29344 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Here, we investigated whether the cell surface glycoprotein CD47 was required for normal formation of osteoblasts and osteoclasts and to maintain normal bone formation activity in vitro and in vivo. In parathyroid hormone or 1α,25(OH)2-vitamin D3 (D3)-stimulated bone marrow cultures (BMC) from CD47(-/-) mice, we found a strongly reduced formation of multinuclear tartrate-resistant acid phosphatase (TRAP)(+) osteoclasts, associated with reduced expression of osteoclastogenic genes (nfatc1, Oscar, Trap/Acp, ctr, catK, and dc-stamp). The production of M-CSF and RANKL (receptor activator of nuclear factor κβ ligand) was reduced in CD47(-/-) BMC, as compared with CD47(+/+) BMC. The stromal cell phenotype in CD47(-/-) BMC involved a blunted expression of the osteoblast-associated genes osterix, Alp/Akp1, and α-1-collagen, and reduced mineral deposition, as compared with that in CD47(+/+) BMC. CD47 is a ligand for SIRPα (signal regulatory protein α), which showed strongly reduced tyrosine phosphorylation in CD47(-/-) bone marrow stromal cells. In addition, stromal cells lacking the signaling SIRPα cytoplasmic domain also had a defect in osteogenic differentiation, and both CD47(-/-) and non-signaling SIRPα mutant stromal cells showed a markedly reduced ability to support osteoclastogenesis in wild-type bone marrow macrophages, demonstrating that CD47-induced SIRPα signaling is critical for stromal cell support of osteoclast formation. In vivo, femoral bones of 18- or 28-week-old CD47(-/-) mice showed significantly reduced osteoclast and osteoblast numbers and exhibited an osteopenic bone phenotype. In conclusion, lack of CD47 strongly impairs SIRPα-dependent osteoblast differentiation, deteriorate bone formation, and cause reduced formation of osteoclasts.

  • 44.
    Koskinen, Cecilia
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Molekylär paradontologi.
    Persson, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Baldock, P.
    Garvan Institute of Medical Research, Darlinghurst, New South Wales.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Lundberg, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Molekylär paradontologi.
    Lack of CD47 leads to impaired bone cell differentiation and results in an osteopenic bone phenotype2012Inngår i: Bone, ISSN 8756-3282, E-ISSN 1873-2763, Vol. 50, nr Supplement 1, S42-S43 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 45. Kumar, Anmol
    et al.
    Kopra, Jaakko
    Varendi, Kart
    Porokuokka, Lauriina L.
    Panhelainen, Anne
    Kuure, Satu
    Marshall, Pepin
    Karalija, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Harma, Mari-Anne
    Vilenius, Carolina
    Lillevaeli, Kersti
    Tekko, Triin
    Mijatovic, Jelena
    Pulkkinen, Nita
    Jakobson, Madis
    Jakobson, Maili
    Ola, Roxana
    Palm, Erik
    Lindahl, Maria
    Strömberg, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Voikar, Vootele
    Piepponen, T. Petteri
    Saarma, Mart
    Andressoo, Jaan-Olle
    GDNF Overexpression from the Native Locus Reveals its Role in the Nigrostriatal Dopaminergic System Function2015Inngår i: PLoS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 11, nr 12, e1005710Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Degeneration of nigrostriatal dopaminergic system is the principal lesion in Parkinson's disease. Because glial cell line-derived neurotrophic factor (GDNF) promotes survival of dopamine neurons in vitro and in vivo, intracranial delivery of GDNF has been attempted for Parkinson's disease treatment but with variable success. For improving GDNF-based therapies, knowledge on physiological role of endogenous GDNF at the sites of its expression is important. However, due to limitations of existing genetic model systems, such knowledge is scarce. Here, we report that prevention of transcription of Gdnf 3'UTR in Gdnf endogenous locus yields GDNF hypermorphic mice with increased, but spatially unchanged GDNF expression, enabling analysis of postnatal GDNF function. We found that increased level of GDNF in the central nervous system increases the number of adult dopamine neurons in the substantia nigra pars compacta and the number of dopaminergic terminals in the dorsal striatum. At the functional level, GDNF levels increased striatal tissue dopamine levels and augmented striatal dopamine release and re-uptake. In a proteasome inhibitor lactacystin-induced model of Parkinson's disease GDNF hypermorphic mice were protected from the reduction in striatal dopamine and failure of dopaminergic system function. Importantly, adverse phenotypic effects associated with spatially unregulated GDNF applications were not observed. Enhanced GDNF levels up-regulated striatal dopamine transporter activity by at least five fold resulting in enhanced susceptibility to 6-OHDA, a toxin transported into dopamine neurons by DAT. Further, we report how GDNF levels regulate kidney development and identify microRNAs miR-9, miR-96, miR-133, and miR-146a as negative regulators of GDNF expression via interaction with Gdnf 3'UTR in vitro. Our results reveal the role of GDNF in nigrostriatal dopamine system postnatal development and adult function, and highlight the importance of correct spatial expression of GDNF. Furthermore, our results suggest that 3'UTR targeting may constitute a useful tool in analyzing gene function.

  • 46.
    Larsson-Nyrén, G
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Sehlin, J
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Anion-selective amplification of glucose-induced insulin secretion.2002Inngår i: Acta Diabetologica, ISSN 0940-5429, E-ISSN 1432-5233, Vol. 39, nr 1, 41-7 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The functional roles of anions on glucose-induced insulin secretion are poorly understood. We investigated the effects of the monovalent anions thiocyanate, iodide, bromide, nitrate and chloride on the dynamics of insulin secretion in isolated pancreatic islets from non-inbred Umeå ob/ob mice. All anion species (12 mM), except Cl-, significantly amplified glucose-induced (20 mM) first- and second-phase insulin secretion (selectivity sequence: SCN->NO3->I->Br->Cl-). Simultaneously, the anions reduced the lag-time prior to the initiation of the secretion (SCN-=I-=NO3->Br->Cl-). The results indicate that pancreatic beta-cell activation can be initiated and amplified by an anion-selective mechanism showing increasing degrees of activation in the order of the anion series of Hofmeister. On the basis of the strikingly similar anion selectivity of amplified secretion and shortened lag-phase, we suggest that both types of anion effects are caused by action at a single site on the beta-cell.

  • 47.
    Larsson-Nyrén, Gerd
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Grapengiesser, Eva
    Hellman, Bo
    Phospholipase A2 is important for glucose induction of rhythmic Ca2+ signals in pancreatic beta cells.2007Inngår i: Pancreas, ISSN 1536-4828, Vol. 35, nr 2, 173-9 s.Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    OBJECTIVES: Pancreatic beta cells respond to glucose stimulation with pulses of insulin release generated by oscillatory rises of the cytoplasmic Ca2+ concentration ([Ca2+]i). The observation that exposure to external ATP and other activators of cytoplasmic phospholipase A2 (cPLA2) rapidly induces rises of [Ca2+]i similar to ordinary oscillations made it important to analyze whether suppression of the cPLA2 activity affects glucose-induced [Ca2+]i rhythmicity in pancreatic beta cells. METHODS: Ratiometric fura-2 technique was used for measuring [Ca2+]i in single beta cells and small aggregates prepared from ob/ob mouse islets. RESULTS: Testing the effects of different inhibitors of cPLA2 in the presence of 20 mM glucose, it was found that N-(p-amylcinnamoyl)anthranilic acid (ACA) removed the oscillations at a concentration of 25 microM, arachidonyl trifluoromethyl ketone (AACOCF3) at 10 microM, and bromoenol lactone (BEL) at 10 to 15 microM. Withdrawal of ACA and BEL resulted in reappearance of the oscillations. Suppression of the arachidonic acid production by addition of 5 microM of the diacylglycerol lipase inhibitor 1,6-bis-(cyclohexyloximinocarbonylamino)-hexane (RHC 80267) effectively removed the [Ca2+]i oscillations, an effect reversed by removal of the inhibitor or addition of 100 microM tolbutamide. Suppression of the arachidonic acid production had a restrictive influence also on the transients of [Ca2+]i supposed to synchronize the beta-cell rhythmicity. Although less sensitive than the oscillations, most transients disappeared during exposure to 50 microM ACA or 35 microM RHC 80267. CONCLUSIONS: The results support the idea that cyclic variations of cPLA2 activity are important for the generation and synchronization of the beta-cell [Ca2+]i oscillations responsible for pulsatile release of insulin.

  • 48.
    Larsson-Nyrén, Gerd
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Pakhtusova, Natalia
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Sehlin, Janove
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Isolated mouse pancreatic β-cells show cell-specific temporal response pattern2002Inngår i: American Journal of Physiology - Cell Physiology, ISSN 0363-6143, E-ISSN 1522-1563, Vol. 282, nr 6, C1199-C1204 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The length of the silent lag time before elevation of the cytosolic free Ca2+ concentration ([Ca2+]i) differs between individual pancreatic beta-cells. One important question is whether these differences reflect a random phenomenon or whether the length of lag time is inherent in the individual beta-cell. We compared the lag times, initial dips, and initial peak heights for [Ca2+]i from two consecutive glucose stimulations (with either 10 or 20 mM glucose) in individual ob/ob mouse beta-cells with the fura 2 technique in a microfluorimetric system. There was a strong correlation between the lengths of the lag times in each beta-cell (10 mM glucose: r = 0.94, P < 0.001; 20 mM glucose: r = 0.96, P < 0.001) as well as between the initial dips in [Ca2+]i (10 mM glucose: r = 0.93, P < 0.001; 20 mM glucose: r = 0.79, P < 0.001) and between the initial peak heights (10 mM glucose: r = 0.51, P < 0.01; 20 mM glucose: r = 0.77, P < 0.001). These data provide evidence that the response pattern, including both the length of the lag time and the dynamics of the subsequent [Ca2+]i, is specific for the individual beta-cell.

  • 49.
    Larsson-Nyrén, Gerd
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Sehlin, Janove
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Rorsman, Patrik
    Lund University, Department of Molecular and Cellular Physiology, Diabetes Research Unit, Lund, Sweden, .
    Renström, Erik
    Lund University, Department of Physiological Sciences, Lund, Sweden, .
    Perchlorate stimulates insulin secretion by shifting the gating of L-type Ca2+ currents in mouse pancreatic B-cells towards negative potentials2001Inngår i: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 441, nr 5, 587-595 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of the chaotrophic anion perchlorate (ClO4-) on glucose-induced electrical activity, exocytosis and ion channel activity in mouse pancreatic B-cells were investigated by patch-clamp recordings and capacitance measurements. ClO4- stimulated glucose-induced electrical activity and increased the action potential frequency by 70% whilst not affecting the membrane potential when applied in the presence of a subthreshold concentration of the sugar. ClO4- did not influence ATP-dependent K (KATP) channel activity and voltage-gated delayed K+ current. Similarly, ClO4- had no effect on Ca2+-dependent exocytosis. The stimulation of electrical activity and insulin secretion was instead attributable to an enhancement of the whole-cell Ca2+ current. This effect was particularly pronounced at voltages around the threshold for action potential initiation and a doubling of the current amplitude was observed at -30 mV. This was due to a 7-mV shift in the gating of the Ca2+ current towards negative voltages. The action of ClO4- was more pronounced when added in the presence of 0.1 mM BAY K8644, whereas no stimulation was observed when applied at a maximal concentration of the agonist (1 mM). Single-channel recordings revealed that the effect of ClO4- on whole-cell currents was principally due to a 60% increase in the mean duration of the long openings and the number of active channels. We propose that ClO4- stimulates insulin secretion and electrical activity by exerting a BAY K8644-like action on Ca2+ channel gating.

  • 50.
    Lernmark, Åke
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Studies on insulin release from the isolated mouse islet1971Doktoravhandling, med artikler (Annet vitenskapelig)
123 1 - 50 of 128
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