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Biomedical subjects

R Unger

Publications and source records attributed to R Unger.

67 records · Page 4Linked to original sources
PubMed1975

Glucagon: role in the hyperglycemia of diabetes mellitus.

Glucagon suppression by somatostatin reduces or abolishes hyperglycemia in dogs made insulin-deficient by somatostatin, alloxan, or total pancreatectomy. This suggests that the development of severe diabetic hyperglycemia requires the presence of glucagon, whether secreted by pancreatic or newly identified gastrointestinal A cells, as well as a lack of insulin. Glucagon suppression could improve therapeutic glucoregulation in diabetes.

Animals↗
PubMed1975

Specific endocrine and hormonal receptor changes associated with liver regeneration in adult rats.

Partial removal of the adult rat liver--a procedure that stimulates liver regeneration--causes arterial levels of insulin and thyroxin to fall and glucagon levels to rise. These changes are correlated with the quantity of liver tissue excised and not solely with nonspecific operative manipulations or with blood glucose levels. During regeneration (about 24 hr postoperatively), hepatic plasma membranes become partially resistant to binding glucagon; this change is specific because it is not detected in laparotomized controls and insulin binding is not significantly altered. It remains to be proven whether any one or more of these specific endocrine changes are casually related to the initiation of hepatic proliferation.

Animals↗
PubMed1975

A morphological basis for intercellular communication between alpha- and beta-cells in the endocrine pancreas.

By degranulating beta-cells in the islets of Langerhans of the rat with sulfonylurea, it has been possible to distinguish unambiguously alpha-cells from beta-cells in freeze-fracture replicas. In such preparations, we found morphologically typical tight and gap junctions occurring between alpha- and beta-cells. The presence of gap junctions offers indirect evidence that these cells are coupled with one another; coupling may influence the secretory behavior of alpha- and beta-cells maintaining glucose homeostasis within tightly constricted limits.

Animals↗
PubMed1975

Cell contacts in human islets of Langerhans.

The freeze-fracturing technique was applied to fresh human islets of Langerhans. With this technique, the inside of cellular membranes was revealed, and specific membrane differentiations, hitherto unknown, were observed in the plasma membrane of the endocrine cells. The specific membrane differentiations represent two types of intercellular junctions, namely the tight junction, which determines a closure of the extracellular space and the gap junction which allows molecules and ions to diffuse from one cell to another (sharing the gap junction) without leaking in the extracellular space (intercellular coupling). The presence of such junctions may be important for the secretory behavior of the cells within the islet.

Adult↗
PubMedDate not supplied

Cytokine expression of HIV-infected monocytes/macrophages at the single-cell level.

Monocytes of healthy donors were infected with HIV1 in vitro: 14-21 days after infection 50-70% of the cells produced p24 HIV1 antigen as detected with anti-p24 immunostaining; infected cultures showed enhanced secretion of interleukin-6 (IL6), interleukin-8 (IL8) and tumour necrosis factor alpha (TNF-alpha). The expression of cytokines on the single-cell level was further analysed by in situ hybridization using nonradioactive digoxigenin for detection. HIV1 (p24+) -producing cells were compared with non-HIV (p24-) -producing cells. All morphological subtypes of macrophages showed HIV production; no difference in cytokine expression was observed. Immunocytochemistry of HIV-infected and uninfected cultures also showed no difference in the pattern of IL1-beta, IL6, IL8 and TNF-alpha protein expression in the cells.

Cytokines↗