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Biomedical subjects

S P Brown

Publications and source records attributed to S P Brown.

15 recordsLinked to original sources
PubMed1992

Physiologic comparison and validation of Stairobic stepping with bench stepping.

To compare the oxygen cost of submaximal exercise on the Stairobic stepping (SS) machine with bench stepping (BS), 12 healthy men and women (mean age 23 years) underwent six different five minute exercise bouts that were randomly assigned. Tests were conducted using standard open circuit calorimetry. SS at 40 and 60 st/min was equal to BS at 20 st/min and SS at 80 st/min was equal to BS at 30 st/min for VE and RER. VO2 was equal at 20 st/min (BS) and 60 st/min (SS), and 30 st/min (BS) and 80 st/min (SS). Stairobic MET (SM) displayed values over-estimated actual MET (AM) values at the two lowest SS rates and under-estimated the AM value at the highest SS rate. Forty-eight observations of the MET response of SS were conducted and analyzed (BMDP2R) in a forward stepping solution. The multiple regression equation calculated for AM was: AM = -0.567 + -0.012 (WT) + 0.063 (rate) + 0.612 (SM) with an adjusted R2 of 0.82 and a SEE of 0.90. The physiologic cost of BS was approximately equal to SS at two to three times the BS rate of stepping.

Adult↗
PubMed1991

The relationship of early versus two-minute recovery echocardiographic values following maximal effort resistance exercise.

Two-dimensionally directed M-mode echocardiography was used to measure left ventricular systolic function following maximal dynamic resistance exercise (RE). Upright measurements were made from the long axis parasternal view at rest, 20 seconds post-exercise, and two minutes post-exercise. Thirty-two successful studies were recorded from a total of 37 trained and untrained male subjects who were heterogeneous as to mode and level of training. Resistance-trained men averaged 3.8 +/- 2.4 yrs of training for 9.7 +/- 3.0 hr/wk, and endurance-trained men averaged 6.4 +/- 3.9 yr of training at 202.5 +/- 112.6 km/wk of cycling, running, and swimming. The trained men competed at the state or regional level. The RE protocol (knee extensions) was performed as follows: Set 1 (10 s rest) Set 2 (10 s rest) Set 3 60% 1-RM@8 reps 60% 1-RM@8 reps 60% 1-RM to fatigue. The RE protocol produced significant post-exercise reductions in end-systolic diameter (p less than 0.0002) and significant post-exercise increases in fractional shortening (p less than 0.0001) and velocity of circumferential fiber shortening (p less than 0.0002). The inotropic variables were still significantly different at two minutes post-exercise compared to the 20 second measure, suggesting that early recovery is a better approximation of maximal values. Velocity of circumferential fiber shortening at 20 seconds and two minutes was significantly correlated (r = 0.39) and fractional shortening was not (r = 0.34) at these serial measurement times.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effects of hydration and dehydration on body composition analysis: a comparative study of bioelectric impedance analysis and hydrodensitometry.

Since 1983, bioelectric impedance has been researched with respect to its validity and reliability in the determination of body composition. It continues to be compared to hydrostatic weighing, the anthropometric "gold standard". This study was designed to investigate the relationship between bioelectric impedance analysis (BIA) and hydrodensitometry (HW) under three conditions: control, hydration and dehydration. Caucasian males (aged 18-44 years) served as subjects (n = 10). Body composition was determined by BIA and HW before intervention, 30 minutes post-hydration, and following a combination of exercise and sitting in a steam room to decrease body weight by two to four percent (mean = 2.81%). Statistical treatment by two-way analysis of variance for repeated measures revealed that although there were no significant differences between the two techniques of body composition determination under any of the three conditions, there was a statistically significant decrease in percent body fat determined in the dehydrated state as compared to the control and hydrated conditions. Recommendations include the determination of hydration state prior to engaging in body composition analysis by either method.

Adipose Tissue↗
PubMed1990

Tail docking.

Explore the source record for details and available documents.

Animal Welfare↗
PubMed1987

Standardization indices of cardiac hypertrophy in weight lifters.

In order to investigate further the use of standardization procedures to determine training effects on cardiac dimension and function, two groups of subjects were analysed noninvasively. A control group of sedentary men (n = 7) and an experimental group of weight lifters (n = 12) volunteered for a standard M-mode echocardiographic assessment. Indices of cardiac function as well as absolute left ventricular dimensions and left ventricular mass were similar between the groups. Standardizing for body surface area and body weight separated the groups. The weight lifters were shown to have a more muscular left ventricular posterior wall. The weight lifters also demonstrated a dilated left ventricle when indexing for body surface area. All other dimensional and volumetric indices were non-significant. The present investigation underlines the need for matching control and experimental groups to biometric variables in order to avoid misinterpreting cardiac enlargement. There is evidence for a true relative hypertrophy in weight lifters as indicated by similar absolute cardiac dimensions and similar biometric variables. Therefore, when evaluating athletes engaged in a chronic pressure overload, cardiac hypertrophy indices should consider body surface area (BSA), body weight and lean body weight (LBW). Future work in this field should incorporate rigorous controls on all biometric variables for better interpretation of hypertrophy in relative or absolute terms.

Adult↗
PubMed1976

Amniotic cell 4-methylumbelliferyl-alpha-glucosidase activity for prenatal diagnosis of Pompe's disease.

Using a simple fluorometric assay for alpha-glucosidase activity of cultured amniotic cells, we have monitored two pregnancies from families at risk for Pompe's disease. The fetus was judged to be affected in one, the pregnancy being terminated and unaffected in the other. The accuracy of these predictions was confirmed. These results suggest that this assay allows accurate prenatal diagnosis of Pompe's disease, three weeks after diagnostic amniocentesis.

Amniotic Fluid↗
PubMed1976

Phenotypic expression of galactokinase deficiency in heterozygous and homozygous subjects: in vivo and in vitro studies.

Cultured fibroblasts derived from a patient homozygous for galactokinase deficiency, his parents, and controls had similar rates of growth in culture media where the only hexose was glucose. However, in media where the only hexose was galactose there was almost no growth of homozygous mutant cells or of maternal heterozygous cells and slight growth of paternal heterozygous cells. Growth of control cells was initially slow, but after a lag period (which coincided with increasing galactokinase activity) growth reached approximately the same levels as in glucose medium. In all cell lines there was a direct relation between the degree of enhancement of galactokinase activity and the ability of cells to adapt to growth in media where the only hexose was galactose. Erythrocyte galactokinase activities in a series of 24 children children with congenital cataracts aged 2-16 years were similar to those in 26 controls. One child in each of the cataract and control groups had 40-50% of mean control activity and was considered to be a potential heterozygote. Galactokinase deficiency (homozygous and heterozygous) is considered to be an uncommon cause of childhood cataracts. Nevertheless, it is an important cause since early dietary treatment can prevent or reverse lens opacities. The heterozygous state may be expressed phenotypically in the patient by the appearance of cataracts and in cultured cells by their defective growth in media where galactose is the only hexose.

Adolescent↗
PubMed1975

A study of consumer attitudes about health care: the control, cost, and financing of health services.

The delivery of health care had emerged as one of the most important political issues of the 1970's, yet public attitudes about health issues remains a relatively unexplored subject. Little is known about the public's opinion of who should control the delivery of health care, about how the costs of health care are perceived, or about how the delivery of care should be financed. This paper relates respondent attitudes on these subjects to attitudes about criteria that determine the respondent's choice of ambulatory care facility and to socioeconomic, political, and other demographic characteristics. The data are derived from a survey (N=521) of households representative of the area of Rochester, New York.

Adolescent↗
PubMedDate not supplied

Prospective scenarios: a method of evaluating new decision tools.

Prospective randomized controlled trials are rarely suitable for the evaluation of new decision making techniques. An approach is described in which a cohort of patients is taken down the usual study pathway to the point at which the new technique would be used. Conventional decision rules are then applied and the results recorded. The new technique is then deployed and the cohort reclassified. The logical and statistical justification for this approach is outlined. More rapid (although possibly less pure) analysis of the effect of the new technique is achieved.

Clinical Trials as Topic↗