Biomechanical comparison of stimulated and nonstimulated skeletal muscle pulled to failure

We compared the biomechanical properties of passive and stimulated muscle rapidly lengthened to failure in an experimental animal model. The mechanical parameters compared were force to tear, change in length to tear, site of failure, and energy absorbed by the muscle-tendon unit before failure. Paired comparisons were made between 1) muscles stimulated at 64 Hz (tetanic stimulation) and passive (no stimulation) muscles, 2) muscles stimulated at 16 Hz (wave-summated stimulation) and passive muscles, and 3) muscles stimulated at 64 Hz and at 16 Hz. Both tetanically stimulated and wave-summation contracted muscles required a greater force to tear (at 64 Hz, 12.86 N more, P less than 0.0004; and at 16 Hz, 17.79 N more, P less than 0.003) than their nonstimulated controls, while there was no statistical difference in failure force between muscles stimulated at 16 Hz and 64 Hz. The energy absorbed was statistically greater for the stimulated muscles than for the passive muscles in Groups 1 and 2 (at 64 Hz, 100% more, P less than 0.0003; and 16 Hz, 88% more, P less than 0.0002). In Group 3, the tetanically contracted muscle-tendon units absorbed 18% more energy than the wave-summated stimulated muscles (P less than 0.01). All muscles tore at the distal musculotendinous junction, and there was no difference in the length increase at tear between muscles in each group. These findings may lead to enhanced understanding of the mechanism and physiology of muscle strain injuries.     

Obesity and beta-blockers: influence of body fat on their kinetics and cardiovascular effects

Beta-blockers are among the most widely used antihypertensive drugs. They differ from each other in regard to several factors such as: beta-agonist activity, beta 1-selectivity and solubility. Aim of this work was to evaluate the influence of obesity on the kinetics and the antihypertensive effect of two Beta-blockers with different solubility such as: the water-soluble, atenolol and the liposoluble, metoprolol. The study was carried out according to an open randomized cross-over design. Eight obese hypertensive patients, after a two week washout period, were randomly allocated to a four week treatment. After a two week intermediate washout period, each patient switched to the other treatment for an additional four week period. On the first and the last day of each treatment the subjects were hospitalized to collect blood samples for the assay of the two drugs and to measure cardiovascular parameters. Obesity does not exert any effect on the kinetics of the water-soluble beta-blocker, atenolol, while markedly interferes with that of the liposoluble, without any apparent influence on its anti-hypertensive effect. These findings extend to obese hypertensives the concept that the plasma concentrations of beta-blocking agents are not reliable predictors of their therapeutic effect.     

港九海底铁路建设中的减压病——工作条件与发病关系探讨

本文介绍香港九龙海底铁路建设中高气压作业与减压病发病情况。该工程有11条坑道,共计259 448个高压工作日,减压288 140人次,发生减压病1 534例。根据不同的工作压力,以暴露次数、高压工作日数及暴露4小时以上次数3种方法分别计算减压病发病率。结果表明:各种方法计算出的发病率都有随工作压力增高而上升的趋势,说明现用的减压表对不同的工作压力达不到同样的预防效果。本文还对3大主要工种和14个小工种的减压病作了分析。     

Quantitative immunocytology as a marker for indications and follow-up of recurrence prevention of superficial urinary bladder cancers

In 1985, we initiated a prospective clinical trial to evaluate the risk of recurrence for superficial bladder cancer. Up to now, 41 patients subjected to TUR have subsequently been monitored by immunocytology with a monoclonal antibody (mab 486 p) recently developed in our laboratory. Of these patients, 15 (36.6%) remained marker-negative and received no prophylactic therapy. There was only one recurrence (6.7%) in this subset of patients, whereas 10 out of 26 (38.5%) marker-positive patients have so far developed recurrent malignancies. In all cases, the conversion of immunocytological characteristics preceded visible recurrence by 2-5 months. These preliminary results indicate that immunocytology might make it possible to identify patients at low risk of recurrence more accurately than has so far been feasible with standard cytology or flow-cytometry.     

The dissociation of visuospatial neglect and neglect dyslexia.

A right-handed man with a left hemisphere lesion extending into the right hemisphere, with evidence of both a left-sided neglect dyslexia and right-sided visuospatial neglect is reported. When copying simple geometric designs he omitted to copy figures on the right-hand side of the page, when bisecting lines he tended to bisect the line to the left of the line's actual centre. He had a neglect dyslexia which was characterised by paralexic errors affecting the beginning (that is, left) of words. The occurrence of these two phenomena provides evidence of a dissociation of these forms of neglect. The findings are discussed in relation to the possible mechanisms of unilateral neglect.