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Biomedical subjects

G G Harrison

Publications and source records attributed to G G Harrison.

At least 73 records · Page 4Linked to original sources
PubMed1983

Comparison in man of total body electrical conductivity and lean body mass derived from body density: validation of a new body composition method.

This article reports a study in which total body electrical conductivity (TOBEC) measurements and lean body mass (LBM) estimated from hydrostatic weighing in human subjects were compared. The TOBEC method provides a new approach to assessment of human body composition that is based on the principle that the electrical conductivity of lean tissue is far greater than that of fat. In a sample of 32 men and women varying widely in age (20 to 53 years), body weight (45 to 155 kg), and adiposity (9.5 to 53.0% body fat), the TOBEC measurement was found to be extremely reliable (r = 0.999) and to correlate highly with hydrostatically estimated LBM (r = 0.903, P less than 0.0001). When the TOBEC scores were transformed to provide a single variable; namely, the subject's height times the square root of the TOBEC score, a higher correlation with LBM was obtained (r = 0.943). Taking gender into account further enhanced the prediction of LBM from TOBEC (r = 0.951). These observations strongly reinforce the results of a previous investigation in which high correlations were found between TOBEC and both total body potassium and total body water. Accordingly, this new method promises to provide a useful technique for the evaluation of body composition that is at once simple, rapid, objective, and noninvasive.

Adult↗
PubMed1983

Measurement of total body electrical conductivity: a new method for estimation of body composition.

A new method for the estimation of body composition in human subjects is described which entails the measurement of total body electrical conductivity. The method is based on the principle that the electrical conductivity of lean tissue is far greater than that of fat. Comparative studies in 19 adults of widely varying fatness have demonstrated excellent correlations between the total electrical conductivity of the subjects and both their total body water (r = 0.87) and total body potassium (r = 0.86). This noninvasive method, which is safe, simple, rapid, and convenient, should prove useful in the nutritional assessment of individuals and populations.

Adult↗
PubMed1983

Association of maternal smoking with body composition of the newborn.

The relationship of maternal cigarette smoking to anthropometric measurements of the newborn was investigated in 285 full-term Caucasian infants. Mothers were classified as "smokers" if they reported smoking both before and during the pregnancy (n = 109) and "nonsmokers" (n = 176). Infants of smoking mothers were significantly lighter, shorter, and had smaller head circumferences, and arm circumferences than those of nonsmokers, consistent with previous findings of other investigators. Ponderal index was not different in the two groups. There was no difference between the two groups in any of the skinfold measurements or in calculated cross-sectional fat area of the upper arm. Multiple regression analyses revealed independent effects of smoking on weight, length, and arm circumference, but no independent effect of smoking on any index of subcutaneous fat. These data suggest that the reduction in birth weight in infants whose mothers who smoke is primarily due to reduction in lean body mass of the newborn while deposition of subcutaneous fat is relatively unaffected.

Adipose Tissue↗
PubMed1983

Lignocaine kinetics during cardiopulmonary bypass. Optimum dosage and the effects of haemodilution.

Lignocaine was administered to patients undergoing cardiopulmonary bypass at 28-29 degrees C in bolus doses of 1.5, 2.5 and 3.5 mg kg-1. Plasma concentrations greater than 1.5 micrograms ml-1 were found briefly and inconsistently in patients receiving the usually recommended dose (1.5 mg kg-1), but reliably for 14 min in those receiving 2.5 mg kg-1. The 3.5 mg kg-1 dose produced statistically and clinically significant decreases in mean arterial pressure. Examination of calculated kinetic parameters showed a two-fold decrease in T1/2 alpha, two-fold increases in T1/2 beta and Vss and unaltered ClP and VP when compared with those of unanaesthetized, normothermic patients. The alteration in pharmacokinetics may be attributed largely to decreased binding to albumin following haemodilution.

Blood Proteins↗
PubMed1982

The effect of vitamin C on the pharmacokinetics of caffeine in elderly men.

The influence of vitamin C on the pharmacokinetics of caffeine was investigated in 10 elderly males, age 66 to 86 yr. Caffeine was administered intravenously on three different occasions over a 7-wk period: before vitamin C restriction, after approximately 4 wk of vitamin C restriction (15 mg dietary intake per day), and after 2 wk of vitamin C supplementation (500 mg orally, twice daily). Blood and urine samples were collected over a 48-h period after each caffeine administration. The plasma half-life, rate constant of elimination, apparent volume of distribution, total body clearance, renal clearance, and metabolic clearance of caffeine were determined. Simultaneous plasma, whole blood and leukocyte vitamin C concentrations were obtained. All of the average vitamin C concentrations monitored (plasma, whole blood, and leukocyte) changed significantly during the study, corresponding to the alterations in dietary vitamin C intake. Conversely, none of the caffeine pharmacokinetic parameters evaluated changed significantly during the study. The average metabolic clearance was approximately 77 (ml hr-1) kg-1 and the average half-life was approximately 4.6 h for all caffeine administrations. These results indicate that the elimination of caffeine in the elderly is not affected significantly by the concentrations of vitamin C achieved during this study.

Aged↗
PubMed1981

Dantrolene sodium in the treatment of malignant hyperthermia. A case report.

The pharmacogenetic syndrome of malignant hyperthermia (MH) in response to general anaesthesia, though rare, is usually fatal when it does occur. A case of anaesthetic-induced MH arising in a 10-year-old girl during intranasal antrostomy and successfully treated with dantrolene sodium (Dantrium; SKF) is described. A treatment protocol for MH is appended. The importance of an awareness on the part of the clinician together with prompt reaction to early tell-tale signs is stressed.

Child↗
PubMed1981

Nutrition studies with White Mountain Apache preschool children in 1976 and 1969.

Nutrition studies were undertaken with two cohorts of White Mountain Apache preschool children, first in 1969 and again in 1976. Under the direction of the same investigator, similar procedures were used in the two studies to evaluate dietary, clinical, and biochemical status. The proportion of children in 1976 with low intakes of calories and of several micronutrients (calcium, vitamin A, vitamin C, thiamin, and iron) and with abnormal biochemical values (hemoglobin, serum iron, vitamin A, and vitamin C), was about half that in 1969. Height for age and weight for age were the same in the two studies. Skinfold thickness were slightly greater in 1976. Overall, these changes in nutritional status were in keeping with changes in the environment and in the economic and health care situations on the Fort Apache Reservation.

Anthropometry↗
PubMed1981

Comparison of body proportions of one-year-old Mexican-American and Anglo children.

The body proportions of 95 Anglo and Mexican-American children aged 48-56 weeks in the Women, Infants, and Children (WIC) Special Supplemental Food Program were determined by use of multiple anthropometric measurements. Ethnic differences were several and collectively define the Mexican-American child as being greater in weight-for-length than the Anglo child with greater chest and thigh circumferences, subscapular skinfolds, and estimated body fat.

Anthropometry↗
PubMed1981

Influence of two haloalkanes on the redox behavior of hepatic microsomal cytochrome b-5 and its possible relationship to stearate desaturase.

The possible interaction of two haloalkanes - bromotrichloromethane and 1,2-dibromo-1,2-dichlorethane - with stearate desaturase was assessed in hepatic microsomes from rats fed a high carbohydrate diet which elevates the levels of stearate desaturase. Both compounds shifted the redox steady state of NADPH reduced hepatic microsomal cytochrome b-5 towards ferricytochrome b-5 and enhanced the re-oxidation of NADH reduced hepatic microsomal cytochrome b-5. The equilibrium constants for the enhancement of microsomal electron transfer by the haloalkanes in these preparations were 2.2 +/- 0.3 mM and 0.46 +/- 0.1 mM for bromotrichloromethane and 1,2-dibromo-1,2-dichlorethane, respectively. The haloalkane mediated enhancement of the oxidation of cytochrome b-5 in hepatic microsomes from rats fed a high carbohydrate diet was diminished by KCN and the inhibitors of cytochrome P-450, CO and/or metyrapone, as well as by fasting of the experimental animals. The I50 values for KCN inhibition of the effects of the haloalkanes on the re-oxidation of cytochrome b-5 (01 mM) were identical to the I50 for KCN inhibition of stearate desaturase (Oshino et al., 1966). The haloalkanes did not affect the activity of hepatic microsomal NADH- or NADPH-cytochrome c reductase, the autoxidation of purified trypsin-cleaved ferrocytochrome b-5 or the conversion of stearoyl CoA to oleate. It is concluded that bromotrichloromethane and 1,2-dibromo-1,2-dichloroethane stimulate hepatic microsomal electron transfer from NADH via cytochrome b-5 by interacting with cytochrome P-450 and with stearate desaturase.

Animals↗
PubMed1981

Anthropology and nutrition: a perspective on two scientific subcultures.

In the last several years serious collaborative efforts between nutrition scientists and anthropologists have begun to bear fruit. To encourage the development of such collaboration, it is useful to consider the professional scientific subcultures of each discipline and how these condition the ways in which we view research problems and methodology. Anthropologists and nutrition scientists share many values and assumptions by virtue of common membership in the larger culture and in the subculture of science. There are substantial differences, however, many of them rooted in the fact that anthropology is primarily an observational science while nutritional science has been primarily experimental in nature. Successful collaboration will result from the formation of long-term communicative relationships rather than from ad hoc utilization of the other discipline. We offer some suggestions for how this may occur, and submit that understanding our own professional subcultures is essential to interdisciplinary efforts.

Anthropology, Cultural↗
PubMed1980

Response of mhs swine to i.v. infusion of lignocaine and bupivacaine.

We report the negative response of MHS swine to i.v. infusion of lignocaine and bupivacaine yielding plasma concentrations which equal or exceed those reported in humans during extradural analgesia. It is concluded that local anaesthetic techniques using the amide-linked local anaesthetics administered in conventional dosage are safe to use in patients known to be genetically susceptible to malignant hyperthermia.

Animals↗