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Biomedical subjects

R Leibowitz

Publications and source records attributed to R Leibowitz.

9 recordsLinked to original sources
PubMed2003

Parent vessel occlusion for vertebrobasilar fusiform and dissecting aneurysms.

BACKGROUND AND PURPOSE: Previous reports of outcome with permanent vessel occlusion (PVO) for large, giant, or fusiform aneurysms in the posterior circulation have been limited. We undertook this study to evaluate the perioperative (within 30 days) and follow-up outcomes for patients treated with permanent occlusion of the vertebral artery for vertebrobasilar fusiform and dissecting aneurysms. METHODS: Thirteen consecutive patients were studied. Two groups were defined for the study. Group I patients underwent PVO to achieve complete thrombosis of the aneurysm. Group II patients underwent PVO to reduce flow to the aneurysm where complete thrombosis was not desirable. Modified Rankin scores were obtained at presentation and at follow-up (follow-up range, 1-76 months; mean, 22.0 months). RESULTS: All group I aneurysms were shown to be thrombosed on the angiograms obtained at the immediate follow-up examinations. Improvement in outcome scores was achieved by all group I patients. Improvement in Rankin scores after endovascular treatment was statistically significant (P =.026). All group II patients had complete occlusion of the vertebral artery; however, continued filling of the fusiform aneurysm was still observed. Four patients in group II died during the follow-up period. Two of these deaths were attributable to the aneurysms. Of the remaining three patients, two experienced clinical worsening and one remained stable. CONCLUSION: In this series, PVO for chronic fusiform and acute dissecting aneurysms of the vertebrobasilar system proved to be a useful therapeutic endovascular technique. Long-term outcomes suggest that patients with aneurysms involving only one vertebral artery, where complete thrombosis can be achieved, have better clinical outcomes than those who have aneurysms involving the basilar artery or both vertebral arteries, where complete thrombosis cannot achieved by using PVO.

Aged↗
PubMed1999

Colorectal cancer and the Muir-Torre syndrome in a Gypsy family: a review.

OBJECTIVES: The Muir-Torre syndrome (MTS) is characterized by an autosomal dominant predilection to sebaceous adenomas, sebaceous carcinomas, and multiple keratoacanthomas, in concert with the cancer phenotype of hereditary nonpolyposis colorectal cancer (HNPCC). Proof that patients showing a familial aggregation of MTS's cutaneous signs in combination with a specific pattern of visceral cancers which are consonant with an HNPCC diagnosis has been buttressed by the discovery of hMSH2 and hMLH1 germ-line mutations in such families. Our purpose in this investigation was to determine the germ-line mutation in a Gypsy family with MTS in concert with HNPCC cancer features, and to provide genetic counseling. An added objective for this paper is to review the literature on MTS. METHODS: We describe a Gypsy family with MTS in concert with HNPCC cancer features, as well as the molecular genetic and genetic counseling procedures used in the interest of improved compliance with cancer control recommendations. We review the clinical phenotype, natural history, and molecular genetics involved in the MTS variant HNPCC. RESULTS: An hMSH2 germ-line mutation was identified as the culprit germ-line mutation in this family. CONCLUSIONS: The presence of the hMSH2 germ-line mutation in this family provides powerful predictability of colorectal and other HNPCC integral cancers. The gastroenterologist must assume an important role in the diagnosis and management of MTS.

Adult↗
PubMed1992

Reduction of plasma cholesterol by lovastatin normalizes erythrocyte membrane fluidity in patients with severe hypercholesterolaemia.

The effect of lovastatin on erythrocyte membrane composition and fluidity was investigated in eight patients with severe hypercholesterolaemia (mean LDL-cholesterol of 7.2 mmol l-1). Lovastatin was administered at a dosage of 40-80 mg for 20 weeks and was discontinued for 5 weeks thereafter. Parallel to a 47% fall in plasma LDL cholesterol, there was a significant reduction (P < 0.01) in erythrocyte membrane cholesterol:phospholipid molar ratio, while erythrocyte membrane fluidity assessed by diphenylhexatriene (DPH) fluorescence polarization increased significantly (P < 0.01). Discontinuation of lovastatin resulted in the reversal of erythrocyte membrane composition and fluidity to pre-treatment values.

Adult↗
PubMed1989

Vitamin C status and other nutritional indices in patients with stroke and other acute illnesses: a case-control study.

Sixty-three patients with acute thrombotic stroke were compared with 47 age and sex-matched patients admitted concurrently with acute ischaemic cardiac pain and a further 44 with acute noncardiovascular illnesses. Overall the stroke patients scored highest on a questionnaire designed to estimate mean daily intake of vitamin C before hospital admission. There were problems with this retrospective dietary assessment, however, and the diet scores of the 27 stroke patients able to answer the questionnaire themselves fell between those of the other two groups. There were no significant differences between the three patient groups in plasma ascorbic acid or uric acid levels, but plasma magnesium and albumin levels were higher in the stroke patients. These findings were similar for patients aged over and under 70 but intergroup differences in magnesium and albumin levels were more marked in the elderly. These results do not support the postulated inverse relationship between vitamin C status and the risk of stroke.

Acute Disease↗
PubMed1983

The effect of preceding anaerobic exercise on aerobic and anaerobic work.

The effects of exercise-induced elevation of lactic acid concentration in blood [Lab] up to 12-14 mM on the subsequent aerobic (less than or equal to VO2 max) and anaerobic (supramaximal) performance was investigated in a group of trained non-athletic subjects. For submaximal loads ranging from 0.6 VO2 max to VO2 max the VO2 max/external work load (Wext) ratio was unaffected by preceding anaerobic exercise, VO2 max was not significantly different, whereas the maximal performance time of a standard exercise was reduced. The kinetics of the VO2 on- adjustment at the onset of 0.9 VO2 max rectangular loads carried out by the arms and/or by the legs was significantly increased by a preceding supramaximal anaerobic load carried out by the same as well as by the non-exercised limbs. It is concluded that in the presence of high [Lab] (1) the maximal aerobic power (VO2 max) is unchanged; (2) the efficiency of aerobic work is unaffected, which implies that during active recovery most La is used as substrate, provided the metabolic level during the latter exceeds 0.6 VO2 max; (3) the endurance for anaerobic as well as for aerobic exercise is reduced; (4) the kinetics of the VO2 adjustment at the onset of submaximal rectangular loads is faster, both in primed and in non-exercised muscles.

Adult↗
PubMed1971

Regulation of protein synthesis in HeLa cells. 3. Inhibition during poliovirus infection.

The mechanism of inhibition of host cell protein synthesis by poliovirus has been studied by examining the behavior of host polyribosomes and polyribosome-associated messenger ribonucleic acid (mRNA). Virus infection appears to result in a specific inhibition of the initiation of translation of host cell mRNA. The site of inhibition does not appear to be mRNA itself. Human cells respond to virus infection by producing a factor antagonistic to the virus inhibition which promotes the initiation of host mRNA translation. The production of the host factor is sensitive to actinomycin; however, the behavior of the host cell factor and that of host mRNA appear distinctly different.

Amino Acids↗