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Biomedical subjects

M Levi

Publications and source records attributed to M Levi.

At least 325 records · Page 18Linked to original sources
PubMed1983

Control of renal hemodynamics and glomerular filtration rate in chronic hypercalcemia. Role of prostaglandins, renin-angiotensin system, and calcium.

The role of prostaglandins (PG), renin-angiotensin system (RAS) and calcium (Ca) in the control of renal hemodynamics and glomerular filtration rate (GFR) in chronic hypercalcemia (serum Ca 12.8 mg%) was studied. Renal blood flow (RBF, 6.39 ml/min per gram kidney weight [gkw]) and GFR (0.52 ml/min per gkw) were significantly decreased in hypercalcemic rats when compared with normocalcemic rats (7.15, P < 0.001 and 0.74, P < 0.05, respectively). These changes in RBF and GFR occurred independent of any significant alterations in systemic hemodynamics, blood and plasma volume. Inhibition of the renal PG with indomethacin resulted in marked decrements in both RBF (6.39-4.12 ml/min per gkw, P < 0.01) and GFR (0.52-0.19 ml/min per gkw, P < 0.01) in hypercalcemic rats, whereas there was no significant alterations in normocalcemic rats. Inhibition of the RAS with captopril resulted in marked increments in both RBF (6.39-7.35 ml/min per gkw, P < 0.05) and GFR (0.52-0.74 ml/min per gkw, P < 0.05) in hypercalcemic rats. In fact, there was no significant difference from the RBF and GFR of similarly treated normocalcemic rats. Similar results were also obtained with the competitive angiotensin II (AII) antagonist (sarcosyl(1)-isoleucyl(5)-glycyl(8)) AII. Since both the renal PG and the RAS are involved in the control of RBF and GFR in hypercalcemia, the role of each is best revealed in the absence of the other. Hence, comparison of the RBF and GFR in the PG-inhibited hypercalcemic rats in the presence of AII (4.12 and 0.19 ml/min per gkw, respectively) and absence of AII (5.99 and 0.53 ml/min per gkw, P < 0.01 for both) reveals the vasoconstrictive role for AII in hypercalcemia. On the other hand, comparison of the RBF and GFR in the AII-inhibited hypercalcemic rats in the presence of PG (7.35 and 0.74 ml/min per gkw, respectively) and absence of PG (5.99 and 0.53 ml/min per gkw, P < 0.01 and P < 0.05, respectively) reveals the vasodilatory role for PG in hypercalcemia. Finally, comparison of the RBF and GFR in both PG- and AII-inhibited hypercalcemic rats (5.99 and 0.53 ml/min per gkw, respectively) with similarly treated normocalcemic rats (7.30 and 0.94 ml/min per gkw, P < 0.001 and P < 0.005, respectively) reveals the vasoconstrictive role for Ca in chronic hypercalcemia. Our study therefore demonstrates that in chronic hypercalcemia the RBF and GFR are controlled by an active interplay of the vasoconstrictive effect of AII, the vasodilatory effect of renal PG, and the direct vasoconstrictive effect of Ca, independent of either AII or PG. The sum total of these forces produces a modest but significant decrease in RBF and GFR.

Angiotensin II↗
PubMed1983

Ethnicity, criminality, and the Buss-Durkee Hostility Inventory.

Scores on the Buss-Durkee Hostility Inventory (BDHI) were analyzed in relation to violent versus nonviolent criminality and ethnic group membership within a sample of adult, male offenders. Although the white, Mexican-American, and black subjects differed on both psychometric and criminological variables, there was no statistically significant association between these predictors and criteria for either the total sample or the individual ethnic groups. The results were seen to contradict recent claims regarding the validity of the BDHI as a discriminator of violent behavior.

Adult↗
PubMed1983

Role of mitochondria in ischemic acute renal failure.

Ischemic ARF is characterized by progressive mitochondrial accumulation of Ca++ which is inversely correlated with the level of oxidative phosphorylation. At least two possibilities exist which would be compatible with these data 1) depressed respiration leads to Ca++ accumulation or 2) increased mitochondrial Ca++ leads to reduced mitochondrial respiration. We favor the latter hypothesis for the reasons outlined above; furthermore, this conclusion is supported by the observations of Lehninger, made some 20 years ago: first, that either oxidative phosphorylation or mitochondrial Ca++ accumulation can be accomplished by intact mitochondria but that these events cannot occur simultaneously and second, that Ca++ accumulation takes precedence over oxidative phosphorylation. Our observation made during post-ischemic reflow that mitochondrial Ca++ accumulation occurs to a significant degree, strongly suggest a potential role for mitochondrial Ca++ overload in the pathogenesis of ARF. Nevertheless, this is not an irreversible pathogenetic process. Clearly, impermeant solutes, vasodilators and Ca++ membrane blockers will alter the natural history of this injury and prevent the severity of the functional defect. A common mechanism of action may involve direct or indirect modification of cellular Ca++ overload in renal vascular and epithelial tissue. The vascular smooth muscle may then revert to a less constricted state with a subsequent more rapid recovery of renal blood flow and that the renal epithelial cell death may be minimized thereby reducing tubular obstruction.

Acute Kidney Injury↗
PubMed1981

MMPI basic scales vs. two-point codes in the discrimination of psychopathological groups.

Made comparisons between MMPI basic scales and two-point codes in the discrimination of brain-damaged, schizophrenic, neurotic, and alcoholic patients (N = 380). Although levels of group differentiation were relatively low for both scales and codes, the latter approach was seen to result in a considerable loss of information and a concomitant reduction in criterion-related validity.

Adult↗
PubMed1981

Interference of the phosphodiesterase inhibitor aminophylline with the plant cell cycle.

Aminophylline (an inhibitor of animal phosphodiesterases) interferes with a pleiotypic program in embryos and seedlings of Haplopappus gracilis, inducing a specific and reversible block of the cell cycle in G1 and G2, partial depression of RNA and protein synthesis and inhibition of the uptake of nucleosides and leucine. The analogy between these effects and those evoked in animal cells by various treatments leading to a rise in cAMP level is discussed.

Aminophylline↗