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Biomedical subjects

J Levi

Publications and source records attributed to J Levi.

At least 163 records · Page 9Linked to original sources
PubMed1982

Effects of parathyroid hormone on oxidative phosphorylation of heart mitochondria.

In an effort to understand the mechanism of action of parathyroid hormone (PTH) on the myocardium, we examined the effect of PTH on the function of isolated heart mitochondria. The hormone inhibited mitochondrial respiration in the presence of malate or beta-hydroxybutyrate but not succinate as substrates. It also inhibited phosphorylation and uncoupled oxidative phosphorylation. These effects of PTH were dose dependent and occurred only in the presence of calcium. A change in calcium concentration from zero to 2 mM did not affect mitochondrial function. PTH also stimulated mitochondrial ATPase. The inhibitory effect of PTH on mitochondrial respiration and on oxidative phosphorylation would result in decreased ATP synthesis and, hence, reduced availability of ATP. Such a sequence of events may provide an explanation for a potential long-term adverse effect of the hormone on the myocardium.

Animals↗
PubMed1981

Therapeutic percutaneous aspiration of pancreatic pseudocysts.

The therapeutic efficacy and safety of percutaneous aspiration of chronic pancreatic pseudocysts was evaluated. Eight patients underwent aspiration a total of ten times. Permanent resolution was obtained in two patients and a third nonsurgical candidate was offered an alternative therapeutic modality. This procedure is simple, rapid, and safe and could become the initial approach to selected patients with a chronic pancreatic pseudocyst.

Adult↗
PubMed1981

Fibre type changes in striated muscle of alcoholics.

Striated muscle from patients taking more than 80 g of alcohol each day shows selective atrophy of the type II fibres which are dependent on glycogenolytic pathways. This atrophy is associated with an excess of glycogen and lipid within the fibres and may represent a selective metabolic insult.

Adult↗
PubMed1981

Androgen-associated hepatoma in a hemodialysis patient.

A patient on hemodialysis treatment developed hepatocellular carcinoma (HCC) after long-term therapy with androgenic anabolic steroids. The tumor progressed very rapidly, and there was no evidence of regression despite discontinuation of the drug. In view of the evidence of an increased of malignancy in patients with chronic uremia and hemodialysis, and of the higher frequency of HCC correlated to treatment with C17-alkylated anabolic steroids, it is necessary to further evaluate the efficiency of this treatment in the aforementioned group of patients.

Aged↗
PubMed1981

Etiology, warning signs and therapy of torsade de pointes. A study of 10 patients.

Torsade de pointes, also called atypical ventricular tachycardia (AVT), was diagnosed in 10 patients, nine on antiarrhythmic therapy and one with acute central nervous system damage. Four patients received quinidine and five disopyramide, either alone or in combination with amiodarone. AVT was dose-dependent in some, but in others, it started shortly after initiation of drug therapy (idiosyncrasy). All patients had QT prolongation longer than 0.60 second immediately before the onset of AVT. This measurement appeared to be a more sensitive predictor of the development of AVT than QTc prolongation or QRS widening. All patients also showed bradycardia before AVT onset. After therapy, the QT immediately decreased, while QTc and QRS remained prolonged for longer periods. Isoproterenol was effective in five of seven patients, but was contraindicated in two others. Ventricular pacing was used in four patients, including the two who did not respond to isoproterenol, and this abolished AVT promptly. Isoproterenol or pacing appear to be the therapy of choice for AVT, while the conventional drugs used to treat the usual form of ventricular tachycardia are not only ineffective, but even contraindicated.

Adult↗
PubMed1981

Synthesizing activity and ultrastructural findings of human blood cells after incubation with cis-platinum "in vitro".

The synthesizing activity and ultrastructural appearance of human polymorphonuclears, lymphocytes and platelets obtained from healthy donors were examined after incubation with cis-platinum (cis-Pt). The drug caused a statistically significant inhibition of DNA, RNA and protein synthesis of the lymphocytes, but their ultrastructure appeared unchanged. On the other hand, incubation of polymorphonuclears with cis-Pt did not affect their protein synthesis but caused a decrease in the number of cytoplasmic granules, mitochondrial alterations, and appearance of membrane ruffles. The drug induced neither inhibition of platelet protein synthesis, nor ultrastructural alterations. The selective effect of this drug on the synthesizing activities of human lymphocytes may be of potential value in the treatment of lymphoproliferative and immunological disorders in man.

Blood Cells↗
PubMed1981

Splenic abscess in infancy--diagnosis by ultrasonography.

Splenic abscess is a rare entity in children, and definite diagnosis is seldom made before operation. A case of splenic abscess in a high-risk infant is reported. An accurate diagnosis has been made preoperatively by ultrasonography. Characteristic sonographic findings are described.

Heart Defects, Congenital↗
PubMed1980

The effect of parathyroid hormone (PTH) and 1,25 dihydroxy vitamin D3 (1,25(OH)2D3) on RNA and heme synthesis by erythroid precursors.

PTH was shown to stimulate RNA and heme synthesis in 12-13 days embryonic mouse liver erythroid cells, thus expressing an erythropoietin-like effect. Incubation of erythroid precursors with 1,25(OH)2D3 had no effect on heme synthesis, and increased the RNA synthesis only slightly, thus showing no enhancement effect of 1,25(OH)2D3 on the PTH stimulating effect on erythropoiesis.

Animals↗
PubMed1980

Mechanism of cis-platinum nephrotoxicity: I. Effects of sulfhydryl groups in rat kidneys.

cis-Diamminedichloroplatinum (CP), an important chemotherapeutic agent, produces acute renal failure by an unknown mechanism. Other heavy metals, such as mercury, are thought to be nephrotoxic by reacting with sulfhydryl (SH) groups. To investigate the mechanism of CP nephrotoxicity, F344 rats were injected once with 6 mg of CP per kg. After 96 hr, the blood urea nitrogen rose to 140 mg/100 ml. The SH concentration in control kidneys was 20.4 +/- 0.1 muml/g wet weight. Total renal SH groups decreased to a maximum of 14% at 120 hr (P less than .01). The fall in SH groups was entirely due to a decrease of protein-bound SH groups. Cell fractionation studies showed that the greatest decline of SH groups occurred in the "mitochondrial" and "cytosol" fractions. These fractions also had the highest Pt concentrations. There was no stoichiometric relationship between Pt accumulation and the change in SH groups. Furthermore, in vitro studies demonstrated that CP does not directly interact with SH groups. To determine if the change in renal SH groups was nonspecific effect of acute injury, renal failure was induced with glycerol (5 g/kg i.m.). Total SH groups per kidney increased after glycerol. These results indicate that the decrease in renal SH groups produced by CP is not due to nonspecific tubular necrosis. The present findings suggest the possibility that the nephrotoxic effects of CP may be related to depletion of SH groups. However, a direct cause-effect relationship has not been established.

Animals↗
PubMed1980

Mechanism of cis-platinum nephrotoxicity: II. Morphologic observations.

Light microscopy, transmission electron microscopy and scanning electron microscopy were used to characterize the morphologic alterations and to localize the site of injury within the kidney 1, 2, 3, 5 and 7 days after the intraperitoneal injection of cis-diamminedichloroplatinum. Pathologic alterations were evident 3 days after the injection of the drug and were localized to the S3 segment of the proximal tubule situated in the outer stripe of the outer medulla. A spectrum of changes was seen in this S3 segment which included a thinning or focal loss of brush border, cellular swelling, condensation of the nuclear chromatin and focal areas of necrosis. After 5 days, widespread tubular necrosis of the S3 segment in the outer stripe was the predominant finding. Necrotic tubular epithelial cells could be seen detaching from the basal lamina and being sloughed into the tubular lumen. Only a bare basal lamina remained in many areas. Regeneration of the S3 segment was seen after 7 days and was characterized by tubules with widely dilated lumens which were lined by many low-lying epithelial cells. The observation that cis-diamminedichloroplatinum exerts its nephrotoxic effect on the S3 segment of the proximal tubule located in the outer stripe of the outer medulla demonstrates that the pattern of injury produced by this antitumor drug is similar to that associated with other nephrotoxic and ischemic models of acute renal failure.

Animals↗
PubMed1979

Functional activity of uremic erythroblast incubated in autologous and homologous plasma.

The uptake of 3H-thymidine, 3H-uridine and 3H-leucine in the erythroid precursors of patients with chronic renal failure (CRF) was examined by radioautography. The pattern of incorporation of the radioactive precursors was similar to that observed in erythroblasts of control subjects, i.e., the uptake decreased with cell maturation. CRF erythroblasts incubated with normal, homologous plasma, showed significant increase in the uptake of the radioactive precursors, compared to the activity of these cells incubated in autologous plasms, the only exception being the incorporation of 3H-leucine in the proerythroblasts, in which the increase was not statistically significant. These results suggest that the impaired function of CRF erythroblasts related to DNA, RNA and protein synthesis is due not to a defective mechanism in the cells themselves, but most probably to the effect of factors present in uremic plasma, the nature of which remains to be detected.

Adult↗
PubMed1979

Increased RNA and heme synthesis in mouse erythroid precursors by parathyroid hormone.

The in vitro effect of parathyroid hormone (PTH) on RNA and heme synthesis by embryonic mouse liver erythroid precursors was examined. PTH produced a dose-dependent effect on RNA synthesis. A maximal increase of 60 +/- 16% (p less than 0.02) was observed with 1.0 U PTH/ml, whereas with higher concentrations a significant decline was found. Furthermore, PTH stimulated heme synthesis after 24 h of incubation. The maximal enhancement of 32 +/- 7% (p less than 0.01) was observed with 0.5 U PTH/ml, a lower effect was obtained with 1.0 U PTH/ml, while 2.0 U PTH/ml caused a pronounced decrease of heme synthesis. These data indicate that PTH affects directly the erythroid precursors by a mechanism similar to that of erythropoietin. The inhibitory effect on the RNA synthesis observed with large doses of PTH may explain at least one of the causes of the anemia reported in patients with primary hyperparathyroidism.

Animals↗
PubMed1979

Bilateral optic neuropathy due to combined ethambutol and isoniazid treatment.

The case of a 40-year-old patient who underwent an unsuccessful cadaver kidney transplantation and was treated with ethambutol and isoniazid is reported. A bilateral retrobulbar neuropathy with an unusual central bitemporal hemianopic scotoma was found. Ethambutol was stopped and only small improvement of the visual acuity followed. Isoniazid was discontinued later, followed by a dramatic improvement in the visual acuity. The hazards of optic nerve toxicity due to ethambutol are known. We emphasize the potential danger in the use of ethambutol and isoniazid.

Adult↗
PubMed1979

Prolonged fever and anemia as the sole manifestations of a false aneurysm in a transplant patient.

A patient with a false aneurysm of the iliac artery following removal of a right allograft developed a prolonged fever and anemia of unknown origin. The patient's condition was initially misinterpreted largely because these symptoms were attributed to dialysis treatment. This case emphasizes fever and anemia as the sole manifestations of a false aneurysm appearing as a late complication of kidney transplantation.

Anemia, Hemolytic↗
PubMed1978

Proximal renal tubular acidosis: association with familial normaldosteronemic hyperpotassemia and hypertension.

Further investigation of a family with normaldosteronemic hyperpotassemia and low-renin hypertension showed seven members from three generations, who ranged in age from 4 to 56 years, to be affected. Results of earlier studies had established a normally functioning renin-aldosterone system and normal renal handling of potassium. Constant, albeit mild and asymptomatic, metabolic acidosis in all those affected prompted bicarbonate loading in both the propositus and his brother, which revealed a maximal renal tubular excretory capacity for bicarbonate reabsorption at serum levels of 18 mmole/liter and proved proximal renal tubular acidosis (PRTA). Further, a linear increase in urinary fractional potassium excretion accompanied that of bicarbonate in both, as in normal individuals. Dextrose-insulin infusion in the brother failed to reduce hyperpotassemia. These data support the hypothesis that a generalized cell membrane defect that specifically impedes potassium influx (as opposed to an isolated renal tubular defect) underlies this autosomal dominant disorder.

Acidosis, Renal Tubular↗
PubMed1978

Early angiography in the management of post-renal biopsy hematuria.

A case is reported in which the value of early angiography in the management of post-renal biopsy hematuria is exemplified. The decision of whether treatment should be conservative or surgical is based on the precise anatomical delineation of the cause of hematuria and the chances of spontaneous remission. When necessary an operation guided by the angiogram can be limited to partial resection of the lesion-bearing region.

Adult↗