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  • 1
    ISSN: 1432-0428
    Keywords: Diabetes mellitus ; hamster ; islet regeneration ; growth factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Partial pancreatic duct obstruction in the hamster leads to the induction of endocrine-cell differentiation and new islet formation. We prepared cytosolic extracts from the partially obstructed pancreas and identified one, which when administered i.p., produced significant increases in the incorporation of tritiated thymidine by ductular and islet cells, as well as a corresponding increase in islet mass. In this study, we evaluate the ability of this extract to reverse streptozotocin diabetes mellitus. Hamsters were treated i. p. twice daily for 7 weeks with either 0.9% NaCl (saline) (n=10) or a cytosol extract (n=10) prepared previously from partially obstructed hamster pancreata. All animals in the cytosol group survived vs only 60% of the saline group (p=0.02). Random blood glucose levels were greater than 22.2 mmol/l in 90% of the saline group vs 40% in the cytosol group (p〈0.05). Pancreatic tissue from the surviving saline animals and from persistently hyperglycaemic cytosol-treated animals, showed intra-cytoplasmic vacuolation of islet cells, a characteristic lesion of sustained hyperglycaemic states. Vacuolation was not observed in normoglycaemic extract treated animals. Islets in hyperglycaemic animals demonstrated a profound decrease or absence of immunoreactive insulin, compared to an abundance of immunoreactive beta cells in cytosol-treated animals that reverted to normoglycaemia. In this group, single cells or nests of cells stained for insulin or glucagon cells were identified in ductal epithelium in association with cells budding from the duct. Morphometric analysis of pancreata in reverted cytosol-treated animals showed a new population of small islets compared with saline controls and an increased islet mass. In summary, streptozotocin diabetes can be reversed by new islet formation induced by local pancreatic growth factors, the exact nature of which remains to be determined.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Reg gene ; islet neogenesis ; cellophane wrap ; hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have reported previously that cellophane wrapping of the hamster pancreas is a stimulus that leads to the induction of duct epithelial cell proliferation, followed by endocrine cell differentiation and new islet formation. Reg is a candidate gene that has been reported to be expressed in regenerating pancreatic islets, suggesting a role in islet growth. We examined Reg gene expression in the cellophane-wrap model by isolating total RNA from hamster pancreata at various times after wrapping. Northern blot analysis using a rat cDNA Reg probe showed no expression of Reg in control non-wrapped hamster pancreas, whereas a strong signal was detected in control wrapped rat pancreas. Using reverse transcription of RNA followed by polymerase chain reaction (PCR) we amplified, isolated and sequenced a 194 base pair product which showed homology to rat Reg in both control and wrapped hamster pancreas. When the PCR product was used as a probe for Northern blot analysis, no signal was detected in control non-wrapped pancreata. In contrast, a strong signal was detected 1 and 2 days after wrapping, which then returned to basal between 4 and 6 days after wrapping. A similar temporal pattern was observed using in situ hybridization to localize the Reg gene. One- and 2-day wrapped but not control pancreas expressed Reg in acinar cells, but not in islets. In conclusion, (a) Reg expression is low in the control hamster pancreas; (b) in the cellophane-wrap model of islet neogenesis, increased Reg mRNA is found within acinar tissue; (c) Reg gene may thus be involved as an acinar paracrine effector of duct cell proliferation in the initial step of islet neogenesis, but may also participate in the inflammatory response to traumatic stimuli.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Keywords Diabetes mellitus ; hamster ; islet regeneration ; growth factors.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Partial pancreatic duct obstruction in the hamster leads to the induction of endocrine-cell differentiation and new islet formation. We prepared cytosolic extracts from the partially obstructed pancreas and identified one, which when administered i. p., produced significant increases in the incorporation of tritiated thymidine by ductular and islet cells, as well as a corresponding increase in islet mass. In this study, we evaluate the ability of this extract to reverse streptozotocin diabetes mellitus. Hamsters were treated i. p. twice daily for 7 weeks with either 0.9 % NaCl (saline) (n = 10) or a cytosol extract (n = 10) prepared previously from partially obstructed hamster pancreata. All animals in the cytosol group survived vs only 60 % of the saline group (p = 0.02). Random blood glucose levels were greater than 22.2 mmol/l in 90 % of the saline group vs 40 % in the cytosol group (p 〈 0.05). Pancreatic tissue from the surviving saline animals and from persistently hyperglycaemic cytosol-treated animals, showed intra-cytoplasmic vacuolation of islet cells, a characteristic lesion of sustained hyperglycaemic states. Vacuolation was not observed in normoglycaemic extract treated animals. Islets in hyperglycaemic animals demonstrated a profound decrease or absence of immunoreactive insulin, compared to an abundance of immunoreactive beta cells in cytosol-treated animals that reverted to normoglycaemia. In this group, single cells or nests of cells stained for insulin or glucagon cells were identified in ductal epithelium in association with cells budding from the duct. Morphometric analysis of pancreata in reverted cytosol-treated animals showed a new population of small islets compared with saline controls and an increased islet mass. In summary, streptozotocin diabetes can be reversed by new islet formation induced by local pancreatic growth factors, the exact nature of which remains to be determined. [Diabetologia (1996) 39: 256–262]
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Molecular and Cellular Endocrinology 32 (1983), S. 301-313 
    ISSN: 0303-7207
    Keywords: estrogen receptor ; hamster ; progesterone induction ; receptor inactivation ; uterus
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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