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Biomedical subjects

G Bellomo

Publications and source records attributed to G Bellomo.

At least 181 records · Page 10Linked to original sources
PubMed1982

Regulation of intracellular calcium compartmentation: studies with isolated hepatocytes and t-butyl hydroperoxide.

In suspensions of isolated hepatocytes, two intracellular Ca2+ pools were distinguished in the presence of the metallochrome indicator arsenazo III, first by treatment with the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and then with the Ca2+ ionophore A23187. The available evidence indicates that the two pools are of mitochondrial and extramitochondrial origin. Metabolism of t-butyl hydroperoxide by hepatocytes caused release of Ca2+ from both compartments concomitant with oxidation of cellular glutathione and NADPH, which was followed by characteristic alterations in cell surface structure. When NADPH oxidation was prevented by selective inactivation of glutathione reductase, t-butyl hydroperoxide metabolism was without effect on the mitochondrial Ca2+ pool, whereas the loss from the extramitochondrial pool was accelerated. Our results suggest that different regulatory mechanisms modulate mitochondrial (NADPH-dependent) and extramitochondrial (thiol-dependent) Ca2+ compartmentation and that disturbance of normal Ca2+ homeostasis may be critical in peroxide-induced cytotoxicity.

Animals↗
PubMed1982

Effects of different beta-receptor antagonists on handgrip in essential hypertension.

To assess the influence of selective and nonselective beta blockers with or without ISA we evaluated the extent of pressor responses to isometric exercise in 15 hypertensive patients who had first been treated with atenolol (100 mg/day) and subsequently with mepindolol (15 mg/day) for 2 months each following placebo administration for 2 weeks. Isometric handgrip was always performed in a supine position. Blood pressure and heart rate were measured at 30% of the maximal voluntary contraction. The percentages of blood pressure increases associated with the isometric test were similar during treatment with the two beta blockers; only heart rate was significantly lower. Systolic and diastolic blood pressures showed a lower increase with mepindolol than with atenolol, but the differences were not statistically significant. In conclusion, cardioselective beta blockers without ISA and nonselective beta blockers with ISA influence systolic and diastolic blood pressure responses to a handgrip of 30% in the same way. Only heart rate shows a lower but rather small increase during the cardioselective drug treatment.

Adrenergic beta-Antagonists↗
PubMed1981

Insulin degradation in human erythrocyte. Effects of reduced glutathione on insulin degradation by hemolysate.

In this study the Authors have evaluated the effects of reduced glutathione on insulin-degrading activity of hemolysate. The GSH increases, in a manner proportional to its concentration, the insulin degradation and this effect is due to the increase the Vmax of the same enzymatic system responsible of insulin degradation observed in absence of exogenous glutathione.

Erythrocytes↗
PubMed1981

Insulin degradation in human erythrocyte. Effects of reduced glutathione on insulin degradation by membrane fractions.

In this study the Authors have evaluated the effects of reduced glutathione on insulin-degrading activity of erythrocyte membrane fractions. The GSH increases, in a manner proportional to its concentration, the insulin degradation by intact membranes, solubilized proteins and membranes treated with Triton X-100. The net increase of degradation is greater for intact and extracted membranes than for solubilized proteins. These data suggest that in human erythrocyte membrane exists an enzymatic system GSH-dependent for insulin degradation and that this system is only partially solubilized by Triton X-100 treatment.

Erythrocyte Membrane↗
PubMed1979

Insulin receptors in human mononuclear leucocytes. II. Binding and degradation of insulin in obese subjects.

The binding of insulin to the receptors on circulating mononuclear cells of obese subjects is significantly decreased when compared to the binding in normal subjects. This fenomenon is due to the reduction of the number of insulin receptors rather than reduction in affinity. The insulin degradation is also reduced, but a very strong correlation, similar to that demonstrated in normal subjects exist between insulin binding to its receptors and insulin degradation.

Adult↗
PubMed1979

Insulin receptors in psoriasis.

We have demonstrated how in psoriasis, irrespective of any diabetic family history, there exists a state of hyperinsulinism with a decreased resistance to insulin, which is aggravated by obesity. Since reviewing the latest studies concerning diabetes at the receptor level, we have carried out a comparative study dealing with insulin receptors in lymphocytes in homogeneous groups of normal, obese, and psoriatics of normal weight and overweight. We have also made a comparison regarding the behaviour of the receptors in these various metabolic states.

Blood Glucose↗
PubMed1979

[The hematic histamina in malignant tumors of alimentary canal and respiratory apparatus (author's transl)].

The Authors estimated the blood histamine level in 39 subjects with malignant tumors of the lung (19), Sthomac (11) and colon (9) and found a significant increase with respect to normal values. Among the groups investigated, the subjects with gastric tumors presented the greatest values. The results show a significant relationship between tumor and hyperhistaminemia as demonstrated by other Authors in experimental animals.

Adult↗
PubMed1979

[Total hematic histamine in gastrectomized patients].

The Authors estimated the blood histamine in 15 patients after gastric-resection and found a significant decrease in all the cases with respect either to basal valus or to normal subjects. The autors suppose it is due to a lower presence of istidin-decarbojlase, owing to removal of gastric tissue where such enzime is placed.

Duodenal Ulcer↗