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Biomedical subjects

A Jackson

Publications and source records attributed to A Jackson.

At least 379 records · Page 21Linked to original sources
PubMed1980

Pulmonary calcification and elastic tissue damage in pseudoxanthoma elasticum.

A case of pseudoxanthoma elasticum with extensive calcification and elastic tissue damage in the lung is described. This patient had classical skin changes, peripheral arterial calcification, and heart block, but no retinal changes. Hypercalcemia was excluded. Pulmonary involvement is in keeping with the concept of the basic abnormality being in the elastic fibres, and such involvement should be considered as a cause of respiratory symptoms in patients with this condition.

Arteries↗
PubMed1980

Instability of the ankle after injury to the lateral ligament.

Ligamentous instability of the ankle joint can be confirmed by radiographs taken in two planes. The place of the anteroposterior varus stress view is established, but the lateral view which shows anterior subluxation of the talus is frequently omitted. The anatomical significance of the two stress views has been determined by dividing different components of the lateral ligament of 20 cadaveric ankles and noting the subluxation that resulted from these procedures. A clinical assessment was then made of 54 ankles (46 patients) with radiological evidence of instability when subjected to varus and anterior stress. Anterior subluxation was found to be considerably more common than varus tilt, and it is therefore suggested that the lateral stress view should be an essential part of the investigation of the unstable ankle.

Adolescent↗
PubMed1980

Does sex make a difference? Gender, age, and stimulus realism in perception and evaluation of aggression.

Judged aggressiveness and its justifiability were examined with caricature cartoons and films of people doing comparable things. Effects of viewer gender, interactant gender, and facial expression were examined. Facial expression strongly affected both types of judgment, viewer gender had no influence, and interactant gender contributed slightly. Real-cartoon differences were significant, but accounted for little variance. Major response patterns were similar for films of people and cartoons. In two developmental studies, only facial expression influenced judgments of friendliness-hostility in cartoons, but condemnation of aggression decreased as viewer age increased. Results with films of real children followed those for cartoons. Facial expression influenced judged aggressiveness, but only viewer age affected judged justifiability. Cross-experiment comparisons revealed that facial expression and the facial expression X real-cartoon interaction yielded major differences on both dependent variables. Subject and interactant gender were not significant for major dependent variables. Results of the developmental studies were similar to adults' suggesting that for judgments of simple aggressive acts, sex makes no difference, but facial expression does make a difference.

Adolescent↗
PubMed1980

A factor analysis of twelve selected maximal isotonic strength performances on the universal gym.

This study sought to isolate and identify the underlying structure of the isotonic strength domain as exhibited on the Universal Gym. Maximal isotonic contractions were elicited from 88 college male subjects involved in a weight training program on 12 selected exercises. Factor analysis was applied to the data to delineate the underlying structure. Analysis of the raw data revealed an unclear nonrobust factor structure. However, when the variance of the anthropometric vaiables of height and weight were statistically held constant from the raw data, subsequent factor analysis of the statiscally controlled data yielded a robust three factor structure. Factor 1 was related to upper extremity and trunk isotonic strength; Factor II, lower extremity isotonic strength; Factor III, trunk and upper extremity isotonic strength. Thus, when evaluating isotonic strength responses on the Universal Gym, upper, lower extremity and trunk measures as body segments should be utilized; also, anthropometric measures of height and weight should be considered.

Body Height↗
PubMed1979

Flexibility in the choice of distinctive features in visual search with blocked and random designs.

An experiment is reported which demonstrates that the features used to detect a character in arrays of similar forms are a function of the stimulus context in which the target is embedded. With the use of blocked and randomised design it was shown that prior knowledge of the background aided search when the feature which was relevant for one backgroind was irrelevant for another, but no significant effect of prior knowledge was obtained when the same feature was useful for the backgrounds.

Discrimination Learning↗
PubMed1979

Tarsal hypermobility after ankle fusion--fact or fiction?

Thirty-seven patients have been reviewed after arthrodesis of the ankle in order to determine the reduction of dorsiflexion and plantarflexion of the foot, the incidence of tarsal hypermobility and its relevance to the clinical results of this procedure. Radiological methods of measuring movements in the foot and tarsus are described and applied to patients who had a normal foot on the opposite side which could be used as a control. Our findings suggest that tarsal hypermobility is not as common as has hitherto been supposed and that a stiff foot with minor radiological degenerative changes in the tarsal joints is quite compatible with an excellent result.

Ankle Joint↗
PubMed1978

The effect of circuit weight training on strength, cardiorespiratory function, and body composition of adult men.

The purpose of this study was to determine the changes elicited by circuit weight training (CWT) and running (RN) programs conducted 3 days/week for 20 weeks. Subjects were randomly assigned to one of three groups: CWT (n = 11); RN (n = 16); and control (n = 14). CWT consisted of 10 exercises performed in 2 sets of 15 reps with 20 to 25 sec rest between exercises. CWT workout time decreased from 30 min to 23 min; exercise heart rate (HR) increased from 79% to 84% max; average weight increased from 42% to 56% of max 1 RM strength and total weight increased 81% (1506 to 2720 lbs/workout). The RN group exercised at 85% max HR for 23 to 27 min/workout. Multivariate and step-down analyses showed the CWT group to be significantly different from the control group at the end of 20 weeks in leg press strength, fat weight, and Vo2 max (1/min). The RN group was significantly different from the CWT group in Vo2 max and treadmill time. Univariate analyses revealed no differences between the CWT and control groups in Vo2 max expressed as ml/kg LBW.min but did show a significant superiority of the RN group over the other two groups in this variable. It was concluded that the CWT program was most specific in improving strength and changing body composition and produced only a small aerobic effect as measured on the treadmill running test.

Adult↗
PubMed1977

General practitioners in the Western Metropolitan Health Region of Sydney.

A comprehensive survey of the number of general practitioners in the Western Metropolitan Health Region of Sydney identified 753 general practitioners with one or more practice locations in the region; this was the equivalent of 711 full-time general practitioners, and represented a general practitioner-population ratio of 1:1533.

Australia↗
PubMed1977

Comparative human oral clinical pharmacology of cefadroxil, cephalexin, and cephradine.

At equivalent oral doses, cefadroxil has a longer serum half-life, slower urinary excretion rate, greater area under the serum level versus time curve than cephalexin or cephradine, and peak serum concentrations that are 75 to 80% those of cephalexin. The calculated, apparent in vivo volume of distribution of cefadroxil is greater than that of cephalexin. These properties infer greater persistence of cefadroxil in serum and urine and more prolonged in vivo bacterial exposure to cefadroxil than to cephalexin or cephradine. Neither cefadroxil nor cephalexin demonstrates drug accumulation on repeated administration. The serum levels achieved by cefadroxil are unaffected by food. The pharmacokinetic properties of cefadroxil are supportive of the development of clinical efficacy data which could indicate that cefadroxil could be administered at 12-h intervals.

Adult↗
PubMed1976

Physical fitness levels vs selected coronary risk factors. A cross-sectional study.

Several studies show significant correlations of blood variables, weight, abnormal electrocardiograms, and blood pressure with the incidence of coronary heart disease, but the quantification of fitness and its correlation with coronary heart disease is more difficult. In this study, approximately 3,000 men, average age of 44.6 years, were examined for blood and lipid profile, pulmonary function, percent body fat determination, and Balke maximal performance treadmill stress testing with multilead ECG monitoring. Five age-adjusted cardiorespiratory fitness categories were determined from treadmill times. A consistent inverse relationship among physical fitness categories and resting heart rate, body weight, percent body fat, serum levels of cholesterol and triglycerides, glucose, and systolic blood pressure, was observed. Forced vital capacity was directly related to levels of fitness. These results, although cross-sectional, imply that physical fitness is related to lower coronary risk factors.

Adult↗
PubMed1976

Alkylation of meseenger RNA by dimethylnitrosamine.

Rats were treated with radioactive dimethylnitrosamine or methyl methanesulphonate and the alkylation of various RNA fractions was determined 4 h later. It was found that after administration of dimethylnitrosamine, hepatic messenger RNA (isolated by binding to oligo(dT)-cellulose) and nuclear RNA were alkylated slightly, but significantly less than ribosomal RNA. After treatment with methyl methanesulphonate nuclear RNA was alkylated to a greater extent than either messenger or ribosomal RNA. The implications of these findings with respect to the mechanism by which dimethylnitrosamine inhibits liver protein synthesis are discussed.

Animals↗
PubMed1976

Prediction of body density in young and middle-aged men.

The purpose of this investigation was to predict body density of young (18-22 yr) and middle-aged (40-55 yr) men and to determine if generalized equations were appropriate to both populations. The dependent variable, body density, was determined by the hydrostatic technique. Independent variables included 7 skinfold fat, 11 girth, and 7 diameter measures; age; height; and weight. Mean body density for young men was 1.068 g/ml (SD +/- 0.014) and percent fat, 13.4 (SD +/- 6.0); the values for middle-aged subjects were 1.043 g/ml (SD +/- 0.0130) and 24.7% (SD +/- 5.9). Incomplete principal components analysis was used to examine the dimensions measured by the independent variables, and these analyses revealed differences between samples. Using multiple regression analysis, with the exception of girth measurements, the slopes of the regression lines were equal. For all analyses, however, the intercepts were different. These results confirmed the need for different regression equations for these populations. The most accurate prediction for young men was with two skinfold, four girth, and two diameter measures (R = 0.88; SE = 0.0069 g/ml); two skinfold and three girth measures accurately predicted body density for middle-aged men (R = 0.84; SE = 0.0074 g/ml).

Adipose Tissue↗
PubMed1976

The measurement of muscle mass in children using [15N]creatine.

In eight infants and children who had recovered from protein-energy malnutrition (PEM), muscle mass was estimated by measuring creatine turnover by an isotope dilution technique using [15N]creatine, creatine concentration, and urinary creatinine output. Creatine turnover varied from 1.5 to 2.6% of the muscle creatine pool per day and muscle creatine concentration ranged from 1.7 to 3.9 mug/mug muscle mass was between 15% and 37% of total body weight. The results indicate that daily creatinine output is not a reliable indicator of muscle mass in children who have recently recovered from severe PEM.

Body Composition↗
PubMed1975

Prediction of body density in young and middle-aged women.

The purpose of this investigation was to predict body density of young and middle-aged women and to determine if the use of a greater variety of variables, particularly those for fat in the bust and hip regions, increases the predictability of body density. Body density determined by the hydrostatic technique (dependent variable) was obtained from 83 volunteer young women and 60 middle-aged women ranging from 18 to 22 and 33 to 50 yr of age, respectively. Independent variables included 8 skinfold, 13 girth, and 7 diameter measures; age; height; weight; and bra and cup sizes. Mean body density for young women was 1.043 g/ml (SD plus or minus 0.014) and percent fat, 24.8 (SD plus or minus 6.4); 1.031 g/ml (SD plus or minus 0.015) and 29.8% (SD plus or minus 6.7) for middle aged subjects. Percent fat was calculated by the formula of Siri. Factor analysis was used to examine the dimensions measured by the independent variables as a function of age. A multiple regression model was used to develop predictions of body density from the independent variables. The best combination of four variables for predicting body density was skinfold thigh, skinfold suprailiac, cup size, skinfold suprailiac, girth waist, and skinfold thigh (R = 0.89) for middle-aged women. The data showed that the highest predictons were found by using combinations of skinfold, girth, and diameter variables; cup size also supported the need for different regression equations for different age groups.

Adolescent↗