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Biomedical subjects

S H Cohn

Publications and source records attributed to S H Cohn.

At least 55 records · Page 3Linked to original sources
PubMed1982

Changes in body composition of cancer patients following combined nutritional support.

The effects of combined nutritional support (parenteral, enteral, and oral) were measured in cancer patients unable to maintain normal alimentation. Changes in body composition were quantified by measurement of total body levels of nitrogen, potassium, water, and fat. The protein-calorie intake of the patients was also evaluated by dietary survey (4-day recall). Standard anthropometric and biochemical measurements for nutritional assessment were obtained for comparison. The dietary evaluation indicated that the dietary supplementation for all patients was more than adequate to meet their energy requirements. Almost all patients gained weight on the combined nutritional support regimens. Determination of body composition indicated that change in body weight was equal to the sum of the changes in body protein, total body water, and total body fat. The findings from the anthropometric nutrition indices (arm muscle circumference and triceps skinfold) were consistent with the results of the body composition study. Information on the nature of the tissue gained was obtained by comparison of body composition data with the ratio of protein:water:lean body mass for normal tissue. The mean gain of protein in the cancer patients was quite small (0.3-0.6 kg). The main change in body weight appeared to be the result of gains in body water and body fat. The total body nitrogen to potassium ratio served to define the extent of tissue anabolism following hyperalimentation. The ratio dropped in the cancer patients following hyperalimentation toward the value of the control subjects on ad libidum diets. The body compartment techniques described have demonstrated their usefulness in determining the effects of hyperalimentation on cancer patients.

Adipose Tissue↗
PubMed1982

Combination therapy for osteoporosis with estrogen, fluoride, and calcium.

Nine women with postmenopausal spinal osteoporosis were treated with combination therapy consisting of estrogen, fluoride, and calcium. Their data were compared with those of a control group treated with fluoride, and calcium without estrogen. Bone mass was measured about every six months by photon absorptiometry (bone mineral content/bone width (BMC/BW)] and total-body neutron activation analysis [total-body calcium (TB Ca)]. Time-trend analysis revealed positive slopes for TB Ca (P = 0.002) and BMC/BW (P = N.S.) for the combination therapy group. The change in BMC/BW in the combination therapy group was significantly different from the response in the fluoride - calcium group. These data suggest that combination therapy may be successful in increasing bone mass in postmenopausal osteoporosis. A clinical trial to establish efficacy and examine risk/benefit ratios should be performed.

Adult↗
PubMed1982

Rate of bone loss in postmenopausal and osteoporotic women.

Regional and total bone mass were determined in three groups of women by photon absorptiometry of the distal radius [bone mineral content BMC)] and total body neutron activation analysis [total body calcium (TBCa)], respectively. There were three groups of patients: group A, osteoporotic women treated with a variety of pharmacologic agents; group B, osteoporotic women (controls) taking only calcium supplements; and group C, normal postmenopausal women. The mean TBCa and BMC were considerably higher in the postmenopausal women than in the osteoporotic women. The rate of change of bone mass in group C was -0.45%/yr and -0.9%/yr for the total skeleton and radius, respectively. Group B had no significant rate of loss, whereas group A demonstrated a significant increase in TBCa of 0.75%/yr with no change in the BMC of the radius. There were no significant between-subject correlations for the slopes (rates of change) of the two bone mineral measurements.

Bone Resorption↗
PubMed1982

Total body nitrogen in health and disease: effects of age, weight, height, and sex.

Total body levels of nitrogen were measured by prompt-gamma neutron activation analysis in 136 healthy adults in the general population (age 20 to 80 years), in 55 cancer patients, and in 20 obese subjects. In order to evaluate the TBN values for the patients, it was necessary to normalize the data for possible differences due to body habitus. This normalization was defined as the ratio of the measured nitrogen level to a predicted nitrogen level derived from the normal population. The parameters of sex, age, Ht, Wt, and fat were used to calculate expected "normal" values of nitrogen. For the cancer patients, an average TBN deficit of less than 10% was observed. Individual patients, however, showed deviations from the TBNp value as large as 28%. For obese patients, the TBN values were normal to slightly high. When adjusted for body size, the deficit of TBN in the cancer patients was approximately half that observed for TBK.

Adult↗
PubMed1981

Hair cadmium content: is it a biological indicator of the body burden of cadmium for the occupationally exposed worker?

The primary objective of this study was to evaluate the cadmium (Cd) levels measured in scalp hair as a potential predictive index of the body burden of Cd. In vivo measurements of kidney and liver Cd along with hair, blood, and urine Cd levels were obtained in 29 industrially-exposed workers and ten control subjects. The relationship of hair Cd levels to the Cd values for the kidney, liver, blood, and urine were tested using nonparametric analyses. In the control group no statistically significant correlations were found. In the Cd-exposed workers with more than one year of employment there were weak correlations (p approximately equal to 0.05); however, the relationships were not sufficiently quantitative for predicting the status of an individual worker. Furthermore, when workers with less than one year of exposure were included in the analysis, no significant correlations were obtained. Although this latter group of workers had low body burdens of Cd, exceptionally high Cd concentrations were found in their hair--an observation that was unexpected. It was concluded that hair Cd levels are not a good index of body burden of Cd in the industrially-exposed individual.

Adult↗
PubMed1981

Total body bone mineral and lean body mass by dual-photon absorptiometry. II. Comparison with total body calcium by neutron activation analysis.

Total body bone mineral (TBBM) was measured in vivo using dual-photon absorptiometry (DPA) in 10 subjects. The total body calcium (TBCa) was measured in the same subjects using neutron activation analysis. The correlation between the two methods was very high (r greater than 0.99) and the standard error of estimate was low. The TBCa relative to TBBM was about 39%. The two noninvasive methods provided nearly identical indications of skeletal mass, but the radiation exposure with DPA was 500 to 5000 times smaller (0.6 mrem vs 300 to 3000 mrem). The radius shaft bone mineral content was highly correlated with the TBBM (0.97) and the TBCa (0.98) and could be used to estimate the latter variables with errors (1 SEE) of 9% and 6%, respectively.

Body Composition↗
PubMed1981

A comparison of methods of assessment of body composition including neutron activation analysis of total body nitrogen.

Fourteen healthy men underwent determinations of total body nitrogen (TBN) by prompt gamma neutron activation analysis and total body potassium (TBK) by whole body counting to estimate the muscle and nonmuscle components of the fat-free body mass (FFBM) and their protein contents. Comparison of FFBM estimated from TBN and TBK (60.6 +/- 6.9 kg, mean +/- SD), densitometry (62.3 +/- 7.1 kg), TBK alone (62.2 +/- 8.0 kg) and TBW (63.9 +/- 7.8 kg) showed no differences among the techniques. Similarly, there were neither differences in fat mass nor percent body fat among the methods. Analysis of the chemical composition of FFBM of this group showed TBK/FFBM = 62.6 +/- 2.3 mEq/kg, TBW/FFBM = 74.6 +/- 0.2%, TBN/FFBM = 32.74 +/- 1.09 g/kg, protein/FFBM = 20.5+/- 0.7%. The calculated mineral content of the FFBM was 6.4%. These values are strikingly similar to the values calculated by direct chemical analysis. It was concluded that the combined TBN-TBK method is a valid technique for estimating body composition in man.

Adipose Tissue↗
PubMed1981

Changes in body composition following therapy of osteoporosis with methandrostenolone.

A two compartment, double-blind, randomized, parallel study was performed comparing methandrostenolone with placebo in the treatment of osteoporosis. The duration of the study was 24 mo. Dependent parameters included total body calcium (TBCa), measured by neutron activation analysis: bone mineral content of the radius (BMC), measured by photon absorptiometry; and total body potassium (TBK), measured by total body counting. A significant increase in TBK occurred in the treated group, primarily in the first 6 mo; thereafter the TBK remained fairly constant. No significant changes in bone mass occurred, except the 6 mo TBCa measurement increased by 11 grams for the methandrostenolone group and decreased by 6 grams for the placebo group (p = .05). Other evidence also suggests that anabolic steroids may not produce sustained uncoupling of bone formation and bone resorption in osteoporosis. If methandrostenolone is capable of producing an increment in bone mass in osteoporosis, it was not readily observable with the sensitivity of the techniques employed in this study

Aged↗
PubMed1981

Compartmental body composition of cancer patients by measurement of total body nitrogen, potassium, and water.

Quantitative measurement was made of body composition in patients with several forms of neoplastic disease. Total body nitrogen was determined by means of the prompt gamma neutron activation technique; total body potassium was measured with the use of a whole body counter. The mass and protein content of the muscle compartment and nonmuscle lean tissue were estimated by application of the technique of compartmental analysis. Total body water, determined simultaneously with the use of tritium label, provided a measure of lean body mass. From these data, the body fat can be inferred. The prompt gamma neutron activation and whole body counting techniques represent a considerable advance over the balance and radioisotope techniques used in earlier studies. The new techniques make possible sequential studies over prolonged periods of time with a considerable degree of accuracy. The loss of body weight by patients with solid tumors consisted primarily of the loss of muscle mass and body fat. Even in severe wasting, the patients appear to retain significant amounts of body fat. It is the skeletal muscle which is predominantly lost; the visceral life-supporting system is, to a considerable extent, spared. The nonmuscle tissue including the visceral fraction did not change in this study, and actually appeared to increase in size when comparison was made with the normal contrast population. The loss of total body water was slight in the cancer patients studied.

Adipose Tissue↗
PubMed1981

Metallothionein excretion in urine upon cadmium exposure: its relationship with liver and kidney cadmium.

The relationships between quantities of accumulated cadmium in the liver and kidney and those of metallothionein in urine was studied in occupationally exposed workers and experimentally exposed rats. Cadmium-exposed workers who had been employed at a cadmium production plant for periods of 8-29 years had significantly higher levels of cadmium in both liver and kidney and excreted significantly larger amounts of metallothionein in urine when compared with workers who had been employed for less than 1 year, with office workers at the plant or with control subjects having no known occupational exposure to cadmium. The excretion of metallothionein in urine of the cadmium-exposed workers appeared to be related to the levels of cadmium in both liver and kidney. A similar dose-effect relationship was also observed among rats given repeated subcutaneous injections of 5 mumol CdCl2/kg. However, in the rats the metallothionein excretion increased markedly when the liver and renal cortex Cd levels exceeded approximately 300 microgram/g and 200 microgram/g, respectively. It appears tht urinary metallothionein may be a useful biological indicator of liver and kidney cadmium levels.

Adult↗
PubMed1981

Critical concentrations of cadmium in human renal cortex: dose-effect studies in cadmium smelter workers.

Cadmium was measured in vivo in the left kidney and liver of 82 industrially exposed workers and 10 control subjects. The range of Cd values for the industrial group was 0.9-57 mg for the whole kidney and 0.8-120 ppm for the liver, compared to 0.4-11.8 mg and 0.6-7.9 ppm for the control group. Below 40 ppm in the liver, the kidney Cd burden tended to increase with increasing liver concentration. Above 40 ppm, the kidney Cd content decreased as the liver concentration increased. This biphasic relation between Cd in the kidney and the liver for all subjects showed a critical level of approximately 31 mg Cd in the kidney. Estimates of the critical level by beta 2-microglobulin and urinary protein measurements yielded critical values of 31-42 mg Cd for the whole kidney (300-400 microgram/g for the renal cortex).

Cadmium↗
PubMed1981

A comparison of 252Cf and 238Pu, Be neutron sources for partial-body in vivo activation analysis.

A comparison is made of the isotopic neutron sources 252 Cf and 238 Pu, Be for partial-body in vivo neutron activation analysis. Depth distributions of thermal neutron fluences in a water phantom are very similar for the two sources. The peak depth occurs at 5 cm. This value is approximately 2 cm less than the values obtained with uncollimated neutrons produced in broad-beam irradiations. With respect to the fluence-to-dose ratio, the 252 Cf neutrons have an advantage of approximately 1.4 over the 238 Pu, Be source. The use of 252 Cf offers two additional advantages for the investigator. First, it minimizes the on-line fast-neutron damage in Ge(Li) semiconductor detectors. Secondly, it is subject to much less stringent transport regulations that 238 Pu, Be. The latter feature takes on particular importance in view of the increasing usefulness of transportable instruments for in vivo cadmium measurements at the workplace.

Beryllium↗
PubMed1981

Calibration of a 238Pu,Be facility for partial-body measurements of organ cadmium.

An improved instrument is described for the measurement of liver and kidney cadmium by in vivo neutron activation analysis in both occupationally and environmentally exposed persons. Detailed calibrations of the instrument used in a study of 83 male workers at a cadmium production plant are give. The importance of accurate organ localisation by ultrasound is stressed, without which errors of 40 and 25% in individual and group kidney measurements, respectively, can occur. The detection limit (2 SD of the background) is 2.2 mg cadmium in the kidney and 1.5 micrograms g-1 (wet weight) in the liver for a local dose of 4.7 mSv. This instrument therefore combines the advantages of portability with high sensitivity of detection of cadmium.

Cadmium↗
PubMed1981

Comparison of methods of estimating body fat in normal subjects and cancer patients.

Total body fat can be indirectly estimated by the following noninvasive techniques: determination of lean body mass by measurement of body potassium or body water, and determination of density by underwater weighing or by skinfold measurements. The measurement of total body nitrogen by neutron activation provides another technique for estimating lean body mass and hence body fat. The nitrogen measurement can also be combined with the measurement of total body potassium in a two compartment model of the lean body mass from which another estimate of body fat can be derived. All of the above techniques are subject to various errors and are based on a number of assumptions, some of which are incompletely validated. These techniques were applied to a population of normal subjects and to a group of cancer patients. The advantages and disadvantages of each method are discussed in terms of their ability to estimate total body fat.

Adipose Tissue↗
PubMed1981

Relationship between endogenous 3-methylhistidine excretion and body composition.

Fourteen healthy men (aged 20-30 yr) consumed two isocaloric, isonitrogenous diets in the sequence of a 4-day meat diet (MD) followed by a 7-day meal-free diet (MFD). Urinary 3-methylhistidine (3MH) excretion during the MD (513 +/- 21 mumol . day-1, mean +/- SE) was significantly higher (P less than 0.01) than day 3 of the MFD (230 +/- 10 mumol . day-1), after which the mean daily 3MH output was constant with a mean coefficient of variation of 4.5%. There was no change in fat-free body mass (FFBM) determined by densitometry at the start (62.3 +/- 1.8 kg) and the end (62.2 +/- 1.9 kg) of the 11-day dietary period. Mean muscle mass (MM) calculated from measurements of total-body potassium and nitrogen was 23.4 +/- 1.3 kg. Endogenous 3MH excretion was related more closely to MM (r = 0.91, P less than 0.001) than to FFBM measured by densitometry (r = 0.81, P less than 0.001). Only a low correlation coefficient (r = 0.33, P less than 0.05) was observed between 3MH and the nonmuscle component of FFBM. Urinary creatinine output also was correlated significantly with 3MH (r = 0.87; P less than 0.001) and MM (r = 0.79; P less than 0.01). It is concluded that because endogenous 3MH is significantly related to MM in man, it can be used as a marker to study in vivo total-body muscle protein degradation provided that the necessary dietary restrictions are observed.

Adult↗