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Biomedical subjects

B Leonard

Publications and source records attributed to B Leonard.

29 records · Page 2Linked to original sources
PubMed1985

Partial neuromuscular blockade and cardiovascular responses to static exercise in man.

In human subjects sustained static contractions of the quadriceps femoris in one leg were performed with the same absolute and the same relative intensity before and after partial neuromuscular blockade with either decamethonium or tubocurarine which reduced strength to about 50% of the control value. During the contractions performed with the same absolute force, the magnitude of the cardiovascular responses (heart rate and blood pressure) was greater during neuromuscular blockade than during control contractions. During the contractions involving the same relative force the magnitude of the cardiovascular responses was almost the same with and without neuromuscular blockade. These findings were independent of the drug used. The metabolic part of the exercise pressor reflex was assessed by the application of an arterial cuff 1/2 min before cessation of exercise and for the following 3 min of rest. Although heart rate and blood pressure decreased after cessation of exercise, application of the tourniquet resulted in higher post-exercise values and this effect was seen both with and without neuromuscular blockade. Muscle biopsies from the subjects' m. vastus lateralis were analysed for fast- and slow-twitch fibre composition showing 27-66% slow-twitch fibres. No correlation was found between cardiovascular responses to static exercise, with or without neuromuscular blockade, and fibre type predominance. The results suggest that the involvement of fast- or slow-twitch muscle fibres does not play a dominant role in the cardiovascular responses to static exercise in man. Both central command and reflex neural mechanisms are of importance, and it appears that these two control mechanisms are redundant and that neural occlusion may be operative. However, when partial neuromuscular blockade induces a disproportion between an increase in central command and a constant or decreasing muscle tension and metabolism, the larger signal arising from central command determines the magnitude of the cardiovascular responses.

Adult↗
PubMed1983

Further studies of the turnover of dog antithrombin III. Study of 131I-labelled antithrombin protease complexes.

Fresh plasma containing 131I-antithrombin III (*I-AT) was coagulated and incubated at 37 degrees C for 2 hr. A "complex peak," separated on heparin-agarose contained AT and *I-AT antigen but no heparin cofactor activity. Crossed immunoelectrophoresis showed only AT complexes. SDS PAGE showed 80% of the *I-AT in a major band (approximately 80,000 daltons), 15% in a minor band (approximately 100,000 daltons) and the rest in trace bands (approximately 60,000 and/or 115,000 daltons). Ammonia treatment of the complex peak released alpha-thrombin. After i.v. injection 80% of the complexed *I-AT, chiefly as the major band, left the plasma with t 1/2 approximately 15 min and was almost immediately catabolized to low molecular weight breakdown products. A major catabolic site was the liver. A simple kinetic model describes the findings approximately.

Animals↗
PubMedDate not supplied

The Centers for Disease Control and Prevention Director's Physical Activity Challenge: an evaluation of a worksite health promotion intervention.

In 1996, the Centers for Disease Control and Prevention launched a 50-day exercise campaign called the "Director's Physical Activity Challenge" to stimulate its employees to exercise. Of the 5822 eligible employees, 3740 (64%) joined, but pre- and post-data was available on only 1192 (20.5%) people. Of this group, 86% of those in contemplation and 64% of those in preparation, and 34% of those in action advanced to a higher stage.

Centers for Disease Control and Prevention, U.S.↗
PubMedDate not supplied

Financial and time costs to parents of severely disabled children.

This paper considers the financial burden of parents caring for severely disabled children. A model to predict parents' out-of-pocket expenses and caregiving time demands is described. Discriminant analysis correctly classified high and low group membership for out-of-pocket expenses and caregiving time at 72 percent and 77 percent, respectively. Expected rates were 50 percent. Time spent caregiving was the best predictor for out-of-pocket expenses, and out-of-pocket expenses was the best predictor of caregiving time. A need-based approach for the distribution of resources that recognizes and adjusts for caregiving time and out-of-pocket costs is recommended.

Adolescent↗
PubMedDate not supplied

Zuni Diabetes Project.

Widespread type II diabetes among North American Indians and certain other populations is a relatively recent medical phenomenon. Increased prevalence of diabetes appears to be related to sudden cultural shifts toward sedentary lifestyle and increased caloric intake. These changes, super-imposed on a genetic predisposition to diabetes, pose a community health threat to the Zuni and similar populations. Regular aerobic exercise is clearly beneficial to most type II diabetics. The key public health issue is how to establish community participation in effective aerobic activity. The Zuni Diabetes Project, fully described here, serves as a model in this respect.

Adult↗