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Biomedical subjects

H C Lukaski

Publications and source records attributed to H C Lukaski.

At least 55 records · Page 3Linked to original sources
PubMed1990

Applications of bioelectrical impedance analysis: a critical review.

Tetrapolar BIA offers great potential for noninvasive assessment of human body composition because it is safe, portable and easy to use. Additional research is needed in clinical studies among patients in whom body composition and fluid status are impaired. However, appropriate reference methods are required to establish the validity of the BIA method. Critical evaluation of the regional measurement of bioelectrical impedance variables for the assessment of human body composition is needed.

Body Composition↗
PubMed1990

Physical training and copper, iron, and zinc status of swimmers.

The influence of physical training on copper, iron, and zinc nutriture was studied before and at the end of a competitive season in 16 female and 13 male swimmers and in 13 female and 15 nontraining control subjects. Mean daily energy, protein, and carbohydrate intakes increased (p less than 0.05) in the swimmers. Estimated copper, iron, and zinc intakes increased (p less than 0.05) in the male swimmers. Hematocrit and hemoglobin did not change but ferritin increased (p less than 0.05) in male swimmers. Plasma copper, iron and zinc were within the ranges of normal values and did not change. Erythrocyte superoxide dismutase (SOD) activity increased (p less than 0.01) after training. The findings indicate that copper, iron, and zinc nutriture is not adversely affected by physical training when dietary intakes are adequate, and that increases in red blood cell SOD activity without an increase in dietary copper are a functional adaptation of copper metabolism to aerobic training.

Adult↗
PubMed1990

Body water and electrolyte responses to acetazolamide in humans.

Acetazolamide (ACZ), a potent carbonic anhydrase inhibitor, is a known diuretic and causal agent in metabolic acidosis. Its diuretic qualities are well established with respect to urine flow and electrolyte excretion. However, the impact of ACZ on body hydration status has not been adequately quantified. Thus, to establish the influence of ACZ treatment on body water, nine healthy males were evaluated for hydration status after clinically prescribed doses of ACZ. The drug was administered in three 250-mg oral doses 14, 8, and 2 h before determination of body water compartments. ACZ led to a significant 1.7-liter reduction in total body water (3.4%). A significant reduction in extracellular water of 3.3 liters is partitioned as the loss of total body water and a significant increase in intracellular water (1.6 liters). Venous blood pH and plasma HCO3- were significantly reduced 0.09 units and 5.9 mM, respectively, with ACZ. Plasma protein concentration was increased, but plasma osmolality did not change. Plasma Na+, K+, and Cl- concentrations were not different with ACZ, but total electrolyte content was significantly decreased 45.2, 1.17, and 44.1 meq, respectively, for all three. Urine K+, HCO3-, flow, and pH were elevated after ACZ treatment, whereas Na+ and Cl- were the same as placebo levels. In conclusion, acute clinical doses of ACZ reduce body fluid compartments, leading to a moderate isosmotic hypovolemia with an intracellular volume expansion as well as metabolic acidosis.

Acetazolamide↗
PubMed1990

Body composition assessment of athletes using bioelectrical impedance measurements.

One hundred and four female and male athletes underwent determinations of hydrodensitometry (HD) and tetrapolar bioelectrical impedance (TBI) under uncontrolled (measurements made without regard to preceding exercise, level of hydration, or eating) and controlled conditions (measurements made two hours after consuming a light meal and no preceding exercise). Fat-free mass (FFM) was estimated from TBI measurements using a previously determined multiple regression equation. No difference (p greater than 0.05) was found in mean FFM values by method or experimental condition. In the uncontrolled state, fat mass and percent body fat (%BF) by impedance were lower (p less than 0.05) than that observed by HD or by TBI under controlled conditions. Linear regression analyses between FFM determined by HD and predicted by TBI under controlled and uncontrolled conditions yielded regression coefficients similar to the line of identify. The relationship between %BF by HD and calculated from impedance-predicted FFM and body mass under uncontrolled conditions was different (p less than 0.05) from the line of identify. In contrast, the regression of densitometric against impedance-predicted %BF under controlled conditions was similar to the line of identify with an error of 2.8%. These findings indicate the need for controlled measurement conditions to obtain valid body composition estimates using the TBI method in healthy people.

Adipose Tissue↗
PubMed1990

Thermogenesis and thermoregulatory function of iron-deficient women without anemia.

Physiological responses at 16 degrees C were studied in 11 women, age 28 +/- 2(mean +/- S.E.) years and 26 +/- 2% fat, after their body iron stores were depleted by diet (5.0 mg iron x 2,000 kcal-1 x d-1), phlebotomy and menstruation for about 80 d and were repleted by diet (13.7 mg iron x 2,000 kcal-1 x d-1) for about 100 d, including daily iron supplementation (50 mg of iron as ferrous sulfate) for the last 14 d of repletion. Iron depletion was characterized by a decline (p less than 0.05) in hemoglobin (12.0 +/- 0.2 g x dl-1), ferritin (5.5 +/- 0.5 ng x ml-1) and body iron balance (-9.1 +/- 2.6 mg x 6 d-1). Iron repletion, including supplementation, increased (p less than 0.05) hemoglobin (12.6 +/- 0.1 g x dl-1), ferritin (9.5 +/- 0.4 ng x ml-1) and iron balance (+67 +/- 6.7 mg x 6 d-1). Iron depletion reduced (p less than 0.05) metabolic heat production (49.6 +/- 1.1 vs 53.6 +/- 1.2 W x m-2) during acute cold exposure. The rates of cooling of the core and periphery were greater (p less than 0.05) during iron depletion than repletion. A shift in the lower core temperature threshold for shivering was paralleled by an earlier onset of shivering (p less than 0.05) in iron depletion indicating an adaptation in cold tolerance in an attempt to maintain core temperature. Iron depletion was associated with blunted post-exposure increases in plasma thyroid hormone concentrations and greater (p less than 0.05) increases in plasma norepinephrine concentrations as compared to iron repletion. In a subsample of the women, no significant effect of calcium or ascorbic acid supplementation was found on responses to cold exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1989

Effects of exercise training on human copper and zinc nutriture.

The findings of our three studies indicate no significant decreases in blood biochemical indices of copper and zinc nutritional status among female and male swimmers during physical training when dietary intakes of these trace elements are adequate (greater than or equal to 67% recommended safe and adequate intake). At these intakes, erythrocyte superoxide dismutase activity increased after physical training indicating a biochemical adaptation of human copper metabolism associated with exercise training. It is noteworthy that this increase in superoxide dismutase activity occurred without an apparent increase in daily copper intake. The calculated copper intakes were 1.3-1.4 and 1.6-1.9 mg/d in the female and male swimmers, respectively. These intakes are less than the suggested value of 2.0 mg/d (Committee on Dietary Allowances, 1980), but they are similar to the reported intakes of other groups in the United States (Klevay et al., 1979). In conclusion, these findings do not appear to support the belief that physical training per se produces adverse effects on copper and zinc nutriture.

Contraceptives, Oral↗
PubMed1989

Comparison of metabolic responses and oxygen cost during maximal exercise using three treadmill protocols.

Sixteen healthy men aged 27.2 +/- 1.2 yr (mean +/- SEM) were tested to volitional exhaustion using the Balke, Bruce, and Ellestad treadmill protocols. Balke resulted in a greater (p less than 0.01) time to exhaustion and total work output, but a lower (p less than 0.05) peak oxygen consumption (ml.kg-1.min-1), and a lower (p less than 0.0001) cumulative net oxygen debt. Oxygen debt, expressed as a percent of total net oxygen cost, was smaller (p less than 0.001) on the Balke than the Bruce and Ellestad protocols (9.9 +/- 0.5, 18.7 +/- 0.6, and 19.3 +/- 0.6%, respectively). The rate of increase in oxygen consumption (p less than 0.0001) and blood lactate concentration (p less than 0.05) were lower on the Balke than on the Bruce and Ellestead protocols. Therefore, the observed differences in oxygen debt and lactate concentrations probably reflect differences in the rate of energy requirement, aerobic and anaerobic metabolism and physiological stress associated with each protocol.

Adult↗
PubMed1989

Maintenance of aerobic capacity and body composition of volunteers residing on a metabolic research unit.

To achieve steady-state energy equilibrium, a program of physiological assessment and aerobic exercise prescription was developed and evaluated in healthy men participating in 3 month (n = 21) and 6 month (n = 12) nutritional studies. Using reliable maximal exercise tests, exercise was prescribed at an intensity to elicit 50% peak oxygen uptake, 15 minutes/day on 3 nonconsecutive days/week. Under controlled controlled conditions of energy intake and exercise prescription, body weight (+/- 2%), body composition, and peak oxygen uptake (+/- less than 5%) were maintained for periods up to 6 months. This approach may be useful in regulating energy expenditure in volunteers participating in controlled metabolic studies for prolonged periods of time.

Adult↗
PubMed1989

Acute renal failure and fluid retention and kidney damage in copper-deficient rats fed a high-NaCl diet.

The effect of an interaction between Cu status and dietary NaCl level on kidney structure, water balance, and the plasma renin-angiotensin-aldosterone system (RAAS) was examined in 64 male Sprague-Dawley rats (178 gm) fed a copper-supplemented diet (CuS) (10 micrograms Cu per gram) or a copper-deficient diet (CuD) (less than 0.7 micrograms Cu per gram), with (CuSNa, CuDNa) or without 3% NaCl for 42 days. NaCl did not affect growth, fluid retention, or kidney ultrastructure in Cu-supplemented rats. Cu deficiency decreased growth rate and kidney Cu, increased plasma cholesterol concentration, and suppressed plasma RAAS. NaCl increased the magnitude of these changes in Cu-deficient rats. The mortality rate was higher in CuDNa (8/16) than in Cu-deficient (2/16) rats. An acute renal failure syndrome characterized by tissue edema, pleural effusion, and ascites occurred in rats fed CuDNa. Bioelectric impedence analysis indicated that body water content was similar in rats fed CuS, CuSNa, and CuD but was higher in edematous and nonedematous rats fed CuDNa. Transmission electron microscopy indicated that glomeruli from Cu-deficient rats were poorly perfused and often occluded by expanded mesangium and contained numerous lysozome-like bodies. Fusion of podocyte foot processes, derangement of glomerular basement membrane, and hypertrophy and lipid accumulation by glomerular capillary endothelium were present in tissue from rats fed CuDNa. These results indicate that Cu deficiency reduces NaCl tolerance in rats. Ultrastructural changes in kidney tissue and the suppression of RAAS in rats fed CuDNa suggest that the edema and ascites result from acute renal failure and not from increased fluid and electrolyte reabsorption.

Acute Kidney Injury↗
PubMed1988

Effects of dietary copper on human autonomic cardiovascular function.

Heart rate and blood pressure responses during supine rest, orthostasis, and sustained handgrip exercise at 30% maximal voluntary contraction were determined in eight healthy women aged 18-36 years who consumed diets varying in copper and ascorbic acid content. Copper retention and plasma copper concentration were not affected by diet. Enzymatic, but not immunoreactive, ceruloplasmin was lower (p less than 0.05) after the low copper and high ascorbic acid diet periods. Diet had no effect on resting supine heart rates, orthostatic responses in heart rate and blood pressure, or standing resting blood pressure. Systolic and diastolic blood pressures were increased significantly (p less than 0.05) during the handgrip test at the end of the low copper and ascorbic acid supplementation periods. Also, the ratio of enzymatic to immunoreactive ceruloplasmin decreased significantly during these dietary treatments. The mean arterial blood pressure at the end of the handgrip test was negatively (p less than 0.0004) correlated with the ceruloplasmin ratios. These findings indicate a functional alteration in human blood pressure regulation during mild copper depletion.

Adolescent↗
PubMed1988

Estimation of body fluid volumes using tetrapolar bioelectrical impedance measurements.

Mathematical equations using tetrapolar bioelectrical resistive (R) and reactive (Xc) impedance measures were developed and crossvalidated to predict total body water (TBW) and corrected bromide space (CBS) in two independent samples (n = 110). Height2 per low R was the best predictor of TBW (R = 0.96) and CBS (R = 0.92). When the influence of TBW was removed from CBS and dependent variables, height2 per low Xc was the best predictor (R = 0.50) of CBS. Double crossvalidation of each sample showed that observed and predicted TBW (R = 0.978 and 9.986) and CBS (0.937 and 0.907) were significantly related (p less than 0.001), and there was no difference (p greater than 0.05) between the values. The lines representing the relationships between observed and predicted values had regression coefficients not different than the line of identity. Data from both samples were combined to give a representative multiple regression equation to predict TBW and CBS. This study establishes the validity of the tetrapolar bioelectrical impedance method to assess body fluid volumes in humans.

Adult↗
PubMed1987

Determination of total body water by deuterium NMR.

A new deuterium nuclear magnetic resonance (2H NMR) method is described for determining total body water in humans. The method has been validated against a standard infrared absorption (IR) procedure using a tracer dose of deuterium oxide (2H2O) of approximately 10 g for each human subject. The precision and accuracy for the methods have been compared and found to be very similar. The advantages of the 2H NMR method over other presently available techniques that are based on 2H2O dilution are as follows: it is fast, accurate, needs only a small dose of 2H2O, can be done using any body fluid, and, most importantly, does not require any sample preparation.

Adult↗
PubMed1987

Methods for the assessment of human body composition: traditional and new.

Renewed interest in the assessment of human body composition has stimulated the need for a balanced understanding of available methodologies of estimating fat-free mass and percent body fat. This review summarizes the physical bases and assumptions, describes applications, and discusses the theoretical and practical limitations of currently available indirect methods. Although standard methods are discussed, recent modifications and adaptations are emphasized.

Adipose Tissue↗
PubMed1987

Effects of level and saturation of fat and iron level and type in the diet on iron absorption and utilization by the rat.

Two 2 X 2 X 2 factorial studies were done to examine the effects of dietary iron level (10 or 35 ppm), percent dietary fat (5 or 30%) and type of fat (safflower or coconut oil) on heme or nonheme iron absorption and other indices of iron status in rats (liver Fe, Hb, delta Hb). Rats were made moderately anemic (Hb 7.8 +/- 0.7 g/dL) by feeding an iron-deficient diet and were then fed one of the 16 experimental diets. Test meals (100 micrograms Fe) labeled with 59Fe were fed after 5 d and 59Fe absorption determined by whole-body counting. Rats were killed after 5 wk and liver Fe, final Hb and delta Hb were determined. Nonheme iron was better absorbed than heme iron regardless of other dietary factors. Both heme iron absorption and nonheme iron absorption were higher when high (30%) rather than low (5%) dietary fat was fed. The type of fat had no effect. Rats fed both nonheme and heme iron had significantly higher Hb, delta Hb and liver iron when fed coconut oil, compared to safflower oil. Rats fed nonheme iron had higher liver Fe, but not Hb or delta Hb, when fed high rather than low dietary fat. Rats fed heme iron had higher Hb, delta Hb and liver Fe when fed high fat than low fat.

Analysis of Variance↗
PubMed1986

Validation of tetrapolar bioelectrical impedance method to assess human body composition.

This study was conducted to validate the relationship between bioelectrical conductance (ht2/R) and densitometrically determined fat-free mass, and to compare the prediction errors of body fatness derived from the tetrapolar impedance method and skinfold thicknesses, relative to hydrodensitometry. One-hundred and fourteen male and female subjects, aged 18-50 yr, with a wide range of fat-free mass (34-96 kg) and percent body fat (4-41%), participated. For males, densitometrically determined fat-free mass was correlated highly (r = 0.979), with fat-free mass predicted from tetrapolar conductance measures using an equation developed for males in a previous study. For females, the correlation between measured fat-free mass and values predicted from the combined (previous and present male data) equation for men also was strong (r = 0.954). The regression coefficients in the male and female regression equations were not significantly different. Relative to hydrodensitometry, the impedance method had a lower predictive error or standard error of the estimates of estimating body fatness than did a standard anthropometric technique (2.7 vs. 3.9%). Therefore this study establishes the validity and reliability of the tetrapolar impedance method for use in assessment of body composition in healthy humans.

Adult↗
PubMed1985

A simple, inexpensive method of determining total body water using a tracer dose of D2O and infrared absorption of biological fluids.

An improved infrared spectrophotometric method using tracer doses of D2O for determination of total body water (TBW) is described. Evaluation of sample preparation procedures showed that only vacuum sublimation yielded acceptable recoveries of D2O standards in the range of 0.01-0.30 mg/ml in urine and plasma (101 +/- 2.5 and 99.6 +/- 2.6%, mean +/- SD, respectively). Oral administration of a 10 g dose of D2O was shown to equilibrate within 2 hr in the saliva and plasma of 10 healthy men and women, including obese (30% body fat) subjects. Calculated TBW was 39.1 +/- 6.4 L which represented 74 +/- 1.6% of the fat free mass determined by hydrodensitometry. The precision of the described infrared method was 2.5%. Based upon the observed sensitivity of this method, it would be possible to administer smaller oral D2O doses, 5-6 g, and obtain reliable TBW values. The practical advantages of this method are low cost and a simple analysis that permits repeated TBW measurements over brief periods without an undue buildup of background deuterium levels in the body.

Adult↗
PubMed1985

Assessment of fat-free mass using bioelectrical impedance measurements of the human body.

A method which involves the measurement of bioelectrical resistive impedance (R) for the estimation of human body composition is described. This method is based upon the principle that the electrical conductivity of the fat-free tissue mass (FFM) is far greater than that of fat. Determinations of R were made in 37 healthy men aged 28.8 +/- 7.1 yr (mean +/- SD) using an electrical impedance plethysmograph with a four electrode arrangement that introduces a painless signal (800 microA at 50 kHz) into the body. FFM was assessed by hydrodensitometry and ranged from 44.6-98.1 kg. Total body water (TBW) determined by D2O dilution and total body potassium (TBK) from whole body counting were 50.6 +/- 10.3 L and 167.5 +/- 38.1 g, respectively. Test-retest correlation coefficient was 0.99 for a single R measurement and the reliability coefficient for a single R measurement over 5 days was 0.99. Linear relationships were found between R values and FFM (r = -0.86), TBW (r = -0.86), and TBK (r = -0.79). Significant (p less than 0.01) increases in the correlation coefficients were observed when the predictor Ht2/R was regressed against FFM (r = 0.98), TBW (r = 0.95), AND TBK (r = 0.96). These data indicate that the bioelectrical impedance technique is a reliable and valid approach for the estimation of human body composition. This method is safe, noninvasive, provides rapid measurements, requires little operator skill and subject cooperation, and is portable. Further validation of this method is recommended in subjects with abnormal body composition.

Adipose Tissue↗