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Biomedical subjects

D G Scarpelli

Publications and source records attributed to D G Scarpelli.

At least 91 records · Page 5Linked to original sources
PubMed1977

Interaction of cyclic AMP and alloxan on insulin secretion in isolated rat islets perifused in vitro.

The interaction of alloxan and cyclic AMP on glucose-induced insulin secretion was studied with the use of isolated rat islet perifusion. Simultaneous perifusion with cyclic AMP and alloxan did not protect the islets against the effect of alloxan. However, addition of dibutyryl cyclic AMP to the alloxan solution produced 40% protection of glucose-induced insulin secretion. Partial protection was obtained with either theophylline (41%) or caffeine alone (54%), and the addition of 1 mg/ml glucose to the theophylline or caffeine solution provided greater than 68% protection. The levels of islet tissue cyclic AMP were more than 2.1 times that of islets not protected against the alloxan effect, when partial or nearly complete reversal of the inhibitory action of alloxan on glucose-induced insulin secretion was effected by theophylline or caffeine. These results suggest that cyclic AMP affords partial protection against the effect of alloxan on glucose-induced insulin secretion.

Alloxan↗
PubMed1975

Preliminary observations on the mitogenic effect of cyclopropenoid fatty acids on rat pancreas.

Male Sprague-Dawley rats were fed a diet containing 500 ppm of cyclopropenoid fatty acids (CPFA). After 2 weeks, mitotic activity and [3H]thymidine incorporation into DNA were significantly increased in pancreatic acinar cells. Continued feeding of the diet for 4 and 8 weeks led to decreasing mitotic activity which was still significantly increased over that of control animals. Focal necrosis of acinar cells was histologically apparent after 8 weeks of CPFA ingestion. Ultrastructural evidence of focal cytoplasmic injury was detected in acinar epithelial cells as early as 2 weeks after feeding of the CPFA diet was begun. A difference in dose response to CPFA appears to exist between Sprague-Dawley and Fischer F344 rats in that the latter, a dose of CPFA (5 mg/100 g body weight), did not evoke a mitogenic response.

Animals↗
PubMed1974

Mitogenic activity of sterculic acid, a cyclopropenoid fatty acid.

Hepatocytes in rainbow trout and rat are stimulated to augmented DNA synthesis and cell division by low concentrations of cyclopropenoid fatty acids in the diet. Sterculic acid isolated as the methyl ester from Sterculia foetida oil has been identified as one of the mitogenic principles.

Animals↗
PubMed1968

Role of anaerobic metabolism in the preservation of functional capacity and structure of anoxic myocardium.

Employing an isolated perfused rat heart preparation, we investigated the contribution of anaerobic metabolic energy to the performance, recoverability, and ultrastructure of the heart perfused at 32 degrees C in 5% albumin in Krebs-Ringer Bicarbonate solution. During exposure to anoxia for 30 min, inclusion in the perfusate of the anaerobic substrate, glucose, resulted in marked improvement in electrical and mechanical performance of the heart and in enhanced recovery during the subsequent period of reoxygenation. Lactate production was fivefold greater in the glucose-supported anoxic heart than in the anoxic heart without glucose. Electron microscope sections of the hearts exposed to anoxia in the absence of glucose revealed alterations in mitochondrial morphology and dilatation of the longitudinal tubules. These morphologic changes during anoxia were averted by inclusion of glucose in the perfusion fluid. The data are consistent with the hypothesis that anaerobic energy generation plays a significant role in preserving myocardial function and structure and in promoting recoverability of the anoxic mammalian heart.

Animals↗