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Biomedical subjects

H Levin

Publications and source records attributed to H Levin.

34 records · Page 2Linked to original sources

Experimental bladder substitution using biodegradable graft of natural tissue.

A controlled experimental study has been performed using a biodegradable graft of natural tissue to achieve vesical augmentation. The graft is progressively reabsorbed while normal capacity is maintained by concomitant regeneration of the layers of the bladder remnant. No significant complications were encountered, and the graft was equally successful when applied either to a histologically normal bladder or to a pathologic bladder of intramural fibrosis. This material is potentially ideal for clinical bladder substitution in humans.

Animals

Alexia without agraphia in a left-handed patient with prosopagnosia.

A left-handed patient was studied who had the acute onset of alexia without agraphia, a left homonymous hemianopia, and prosopagnosia. Neurodiagnostic tests including computerized axial tomography and angiography disclosed bilateral lesions in the posterior cerebral hemispheres involving the splenium of the corpus callosum. Neuropsychologic examination indicated marked impairment of facial discrimination, deficient naming and memory of presented visual material, and mild visual agnosia with relative preservation of other cognitive functions. These findings are consistent with a double disconnection syndrome involving disconnection of the dominant angular gyrus and right inferotemporal cortex from their bilateral visual inputs.

Agnosia

Capsule reconstruction.

In this article, the author discusses the general concept of of capsule reconstruction and emphasizes the importance of discriminative judgement in in capsule reconstruction. He reviews capsular composition and histology, as well as varied capsulotomy procedures.

Humans

Meta-analysis of clinical trials as a scientific discipline. I: Control of bias and comparison with large co-operative trials.

Meta-analysis is an important method of bridging the gap between undersized randomized control trials and the treatment of patients. However, as in any retrospective study, the opportunities for bias to distort the results are widespread. Attempts must be made to introduce the controls found in prospective studies by blinding the selection of papers and extraction of data and making blinded duplicate determinations. Informal and personalized methods of obtaining data are probably more liable to error and bias than employing only published data. Publication bias is a serious problem requiring further research. There also need to be more comparisons of meta-analysed small studies with large co-operative trials.

Adrenergic beta-Antagonists

Meta-analysis of clinical trials as a scientific discipline. II: Replicate variability and comparison of studies that agree and disagree.

The replicate variability of meta-analyses of controlled clinical trials has been assessed as a measure of scientific precision. 46 of 91 known meta-analysis papers were divided into 20 cohorts of studies of the same therapies. Ten cohorts contained meta-analyses with different statistical conclusions; 14 contained differing clinical conclusions with a wider spread than the statistically differing studies. Possible causes of variability, such as different trials included, different policies regarding the inclusion of non-randomized and unpublished trials, and different statistical methodologies, were not obvious causes of differing conclusions. Further work in this area should include multivariate analyses in order to explore possible interactions in the factors accounting for the variability found in replicate meta-analyses.

Clinical Trials as Topic

Building materials and indoor air quality.

New building materials, products, and furnishings are known to emit a large number of organic chemicals into indoor air. The author addresses the effects of volatile organic compounds (VOCs) on building occupants, including building materials evaluation and strategies to reduce airborne concentrations. A major problem is that little is known about the specific health effects of most VOCs at the low concentrations usually found in indoor environments.

Air Pollutants, Occupational