SARS-CoV-2 exposures among healthcare workers in New York City.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a significant impact on hospitals, including the occupational health departments in charge of handling healthcare worker (HCW) staffing during high rates of exposure and infection of HCWs. HCWs who were exposed to a patient or community member infected with SARS-CoV-2 were required to isolate from work for a minimum of 14 days from the date of exposure. AIMS: This study was aimed to assess the relative risk of SARS-CoV-2 infection following different types of workplace and community exposures. METHODS: We analyzed the details of workplace and community exposures of HCWs to SARS-CoV-2 at Montefiore Medical Center in New York between 22 June 2020 and 22 November 2020. RESULTS: Of 562 HCW SARS-CoV-2 exposures analyzed, 218 were from the community and 345 were from the workplace. Twenty-nine per cent of community exposures resulted in infection, which was significantly greater than workplace exposure infection (2%). Household community exposures resulted in a larger frequency of infection than non-household community exposures. Of the seven infections after workplace exposures, five had qualifying exposures to a co-worker and two were exposed to an infected patient during a non-aerosolized procedure. CONCLUSIONS: HCW exposure to SARS-CoV-2 continues to present staffing challenges to healthcare systems. Even with deviations from standard personal protective equipment protocol, workplace exposures resulted in low frequencies of infection. In our study, the primary source of HCW infection was exposure in the community. Our findings support investing in efforts to educate around continued masking and social distancing in the community in addition to interventions targeted at addressing vaccine hesitancy.

The impact of positive resection margins in partial laryngectomy for advanced laryngeal carcinomas and radiation failures.

OBJECTIVES: To investigate the prognostic significance of positive margin and disease course in partial laryngectomy for advanced laryngeal carcinoma and radiation failure. DESIGN: Retrospective case control study. SETTING: A major tertiary referral centre. PARTICIPANTS: Patients who underwent partial laryngectomy for advanced laryngeal carcinoma or for radiation failure with at least 2 years of follow-up. MAIN OUTCOME MEASURES: Margin status versus primary treatment and salvage treatment versus disease-free survival and overall survival. RESULTS: Twenty nine patients with sufficient follow-up data were found. Twelve patients had histological positive margin. Five of the 12 patients with a histological positive margin failed surgery as did four patients with clear margins. A positive margin had no effect on disease-free survival (P = 0.287) but was associated with poorer overall survival (P = 0.051). Of 11 patients treated primarily with surgery, recurrence was documented in one of eight with a positive margin and none of three with clear margins. Of 18 patients who underwent surgery secondary to radiation failure, recurrence was documented in all four with a positive margin and 4 of 14 with negative margins. Extended frontolateral resection, performed only in radiation failures, was associated with worse disease-free survival. CONCLUSIONS: Non-irradiated patients with involvement of a single margin after partial laryngectomy may be spared total laryngectomy if adjuvant radiation is administered. Patients who fail radiation should undergo radical partial laryngectomy, with conversion to total laryngectomy in those with a positive margin.

Thermic effect of food at rest, during exercise, and after exercise in lean and obese men of similar body weight.

The thermic effect of food at rest, during 30 min of cycle ergometer exercise, and after exercise was studied in eight lean (mean +/- SEM, 10 +/- 1% body fat, hydrostatically-determined) and eight obese men (30 +/- 2% body fat). The lean and obese mean were matched with respect to age, height, weight, and body mass index (BMI) to determine the relationship between thermogenesis and body composition, independent of body weight. All men were overweight, defined as a BMI between 26-34, but the obese had three times more body fat and significantly less lean body mass than the lean men. Metabolic rate was measured by indirect calorimetry under four conditions on separate mornings, in randomized order, after an overnight fast: 3 h of rest in the postabsorptive state; 3 h of rest after a 750-kcal mixed meal (14% protein, 31.5% fat, and 54.5% carbohydrate); during 30 min of cycling and for 3 h post exercise in the postabsorptive state; and during 30 min of cycling performed 30 min after the test meal and for 3 h post exercise. The thermic effect of food, which is the difference between postabsorptive and postprandial energy expenditure, was significantly higher for the lean than the obese men under the rest, post exercise, and exercise conditions: the increments in metabolic rate for the lean and obese men, respectively, were 48 +/- 7 vs. 28 +/- 4 kcal over 3 h rest (P less than 0.05); 44 +/- 7 vs. 16 +/- 5 kcal over 3 h post exercise (P less than 0.05); and 19 +/- 3 vs. 6 +/- 3 kcal over 30 min of exercise (P less than 0.05). The thermic effect of food was significantly negatively related to body fat content under the rest (r = -0.55), post exercise (r = -0.66), and exercise (r = -0.58) conditions. The results of this study indicate that for men of similar total body weight and BMI, body composition is a significant determinant of postprandial thermogenesis; the responses of obese are significantly blunted compared with those of lean men.

Body composition, not body weight, is related to cardiovascular disease risk factors and sex hormone levels in men.

To clarify the independent relationships of obesity and overweight to cardiovascular disease risk factors and sex steroid levels, three age-matched groups of men were studied: (i) 8 normal weight men, less than 15% body fat, by hydrostatic weighing; (ii) 16 overweight, obese men, greater than 25% body fat and 135-160% of ideal body weight (IBW); and (iii) 8 overweight, lean men, 135-160% IBW, but less than 15% fat. Diastolic blood pressure was significantly greater for the obese (mean +/- SEM, 82 +/- 2 mmHg) than the normal (71 +/- 2) and overweight lean (72 +/- 2) groups, as were low density lipoprotein levels (131 +/- 9 vs. 98 + 11 and 98 + 14 mg/dl), the ratio of high density lipoprotein to total cholesterol (0.207 +/- 0.01 vs. 0.308 +/- 0.03 and 0.302 +/- 0.03), fasting plasma insulin (22 +/- 3 vs. 12 +/- 1 and 13 +/- 2 microU/ml), and the estradiol/testosterone ratio (0.076 +/- 0.01 vs. 0.042 +/- 0.02 and 0.052 +/- 0.02); P less than 0.05. Estradiol was 25% greater for the overweight lean group (40 +/- 5 pg/ml) than the obese (30 +/- 3 pg/ml) and normal groups (29 +/- 2 pg/ml), P = 0.08, whereas total testosterone was significantly lower in the obese (499 +/- 33 ng/dl) compared with the normal and overweight, lean groups (759 +/- 98 and 797 +/- 82 ng/dl). Estradiol was uncorrelated with risk factors and the estradiol/testosterone ratio appeared to be a function of the reduced testosterone levels in obesity, not independently correlated with lipid levels after adjustment for body fat content. Furthermore, no risk factors were significantly different between the normal and overweight lean groups. We conclude that (a) body composition, rather than body weight per se, is associated with increased cardiovascular disease risk factors; and (b) sex steroid alterations are related to body composition and are not an independent cardiovascular disease risk factor.

Independent effects of obesity and insulin resistance on postprandial thermogenesis in men.

The putative blunted thermogenesis in obesity may be related to insulin resistance, but insulin sensitivity and obesity are potentially confounding factors. To determine the independent effects of obesity and insulin resistance on the thermic effect of food, at rest and after exercise, lean and obese men were matched at two levels of insulin sensitivity determined by insulin-stimulated glucose disposal (milligrams per kilogram fat-free mass [FFM] per minute) during the euglycemic, hyperinsulinemic (40 mU/m2.min) clamp: 5.4 mg/kg FFM for the lean and obese groups with low insulin sensitivity, and 8.1 mg/kg FFM for the groups with high insulin sensitivity. The two lean groups were matched for percent fat (approximately 15 +/- 1% fat), as were the two obese groups (approximately 33 +/- 2% fat). Energy expenditure was measured for 3 h in the fasting state and for 3 h after a 720-kcal mixed meal, each at rest and immediately after 1 h of cycling at 100 W. The thermic effect of food (TEF) was calculated as the postprandial minus fasting energy expenditure (kcal/3 h) during rest and after exercise. During rest, TEF was blunted by both obesity (24 +/- 5 and 34 +/- 6 kcal/3 h for obese groups with low and high insulin sensitivity vs. 56 +/- 6 and 74 +/- 6 kcal/3 h for the lean groups with low and high insulin sensitivity; P less than 0.01 lean vs. obese) and insulin resistance (insulin-resistant less than insulin-sensitive, at both levels of obesity; P less than 0.01). After exercise, TEF was also impaired in the obese (47 +/- 6 and 44 +/- 5 kcal/3 h for the insulin-resistant and -sensitive groups) and in the lean insulin-resistant (55 +/- 5 kcal/3 h), compared with the lean insulin-sensitive men (71 +/- 3 kcal/3 h), P less than 0.01. Compared with rest, TEF after exercise was improved, but not normalized, in both obese groups (P less than 0.05), but unchanged in the lean groups. These results suggest that both insulin resistance and obesity are independently associated with impaired TEF at rest, but the responsiveness of thermogenesis to exercise before a meal is related to the obese state and not independently to insulin resistance per se.

Relationship between insulin sensitivity and plasma leptin concentration in lean and obese men.

Alterations in the production of or the sensitivity to leptin, the protein encoded by the ob gene, cause obesity and diabetes in rodents. We evaluated the isolated relationship between leptin and insulin sensitivity in lean and obese humans. Three groups of subjects who were carefully matched for either insulin sensitivity (determined by the modified intravenous glucose tolerance test and minimal model analysis) or adiposity (determined by hydrodensitometry) were studied: 1) lean insulin-sensitive men (percentage body fat, 15 +/- 1%); 2) lean insulin-resistant men (percentage body fat, 16 +/- 1%), matched on percentage body fat and fat mass with the lean insulin-sensitive group; and 3) obese insulin-resistant men (percentage body fat, 31 +/- 3), matched on insulin sensitivity with the lean insulin-resistant group. Basal plasma leptin concentrations were significantly lower in the lean insulin-sensitive than in the lean insulin-resistant men (1.90 +/- 0.4 vs. 4.35 +/- 1.21 ng/ml, P < 0.05) despite identical body composition. Plasma leptin in the obese men (9.27 +/- 1.4 ng/ml) was significantly higher than values in the two lean groups (P < 0.01). Marked alterations in plasma glucose and insulin concentrations induced by glucose and tolbutamide injection did not cause any change in plasma leptin levels. These results demonstrate that insulin resistance is associated with elevated plasma leptin levels independent of body fat mass. However, plasma insulin itself does not acutely regulate leptin production.

Profound peripheral insulin resistance, independent of obesity, in polycystic ovary syndrome.

Hyperinsulinemia secondary to a poorly characterized disorder of insulin action is a feature of the polycystic ovary syndrome (PCO). However, controversy exists as to whether insulin resistance results from PCO or the obesity that is frequently associated with it. Thus, we determined in vivo insulin action on peripheral glucose utilization (M) and hepatic glucose production (HGP) with the euglycemic glucose-clamp technique in obese (n = 19) and nonobese (n = 10) PCO women and age- and body-composition-matched normal ovulatory women (n = 11 obese and n = 8 nonobese women). None had fasting hyperglycemia. Two obese PCO women had diabetes mellitus, established with an oral glucose tolerance test; no other women had impairment of glucose tolerance. However, the obese PCO women had significantly increased fasting and 2-h glucose levels after an oral glucose load and increased basal HGP compared with their body-composition-matched control group. There were statistically significant interactions between obesity and PCO in fasting glucose levels and basal HGP (P less than .05). Steady-state insulin levels of approximately 100 microU/ml were achieved during the clamp. Insulin-stimulated glucose utilization was significantly decreased in both PCO groups whether expressed per kilogram total weight (P less than .001) or per kilogram fat free mass (P less than .001) or when divided by the steady-state plasma insulin (l) level (M/l, P less than .001). There was residual HGP in 4 of 15 obese PCO, 0 of 11 obese normal, 2 of 10 nonobese PCO, and 0 of 8 nonobese normal women. The metabolic clearance rate of insulin did not differ in the four groups. We conclude that 1) PCO women have significant insulin resistance that is independent of obesity, changes in body composition, and impairment of glucose tolerance, 2) PCO and obesity have a synergistic deleterious effect on glucose tolerance, 3) hyperinsulinemia in PCO is not the result of decreased insulin clearance, and 4) PCO is associated with a unique disorder of insulin action.

Evidence for distinctive and intrinsic defects in insulin action in polycystic ovary syndrome.

Women with PCO have a unique but poorly characterized disorder of insulin action. Obese (n = 16) and nonobese (n = 14) PCO women and age- and weight-matched normal, nondiabetic ovulatory women (obese, n = 15; nonobese, n = 17) had insulin action determined in vivo with sequential multiple insulin dose euglycemic clamps and in isolated abdominal adipocytes to clarify the mechanisms of insulin resistance. PCO resulted in significant increases in the ED50 insulin for glucose utilization in vivo (P less than 0.001) and in adipocytes (P less than 0.01), without significant changes in adipocyte insulin-binding sites. PCO also resulted in significant decreases in maximal insulin-stimulated rates of glucose utilization in vivo (P less than 0.01) and in adipocytes (P less than 0.01). Obesity resulted in smaller decreases in insulin sensitivity than PCO (ED50 insulin, P less than 0.001 in vivo and P less than 0.05 in adipocytes), but greater decreases in insulin responsiveness (Vmax, P less than 0.001 in vivo and in adipocytes). The ED50 insulin for suppression of HGP was increased only in obese PCO women (P less than 0.001), and the interactions between PCO and obesity on this parameter were statistically significant. No significant correlations between androgen or estrogen levels and adipocyte insulin binding or action were found. Because insulin binding was not changed, we conclude that the major lesion causing insulin resistance in PCO is a striking decrease in insulin sensitivity secondary to a defect in the insulin receptor and/or postreceptor signal transduction. PCO also is associated with modest but significant decreases in glucose transport. These defects in insulin action appear to represent intrinsic abnormalities that are independent of obesity, metabolic derangements, body fat topography, and sex hormone levels. Conversely, changes in hepatic insulin sensitivity appear to be acquired with obesity.

Effects of weight loss with orlistat on glucose tolerance and progression to type 2 diabetes in obese adults.

BACKGROUND: Orlistat is a gastrointestinal lipase inhibitor that reduces dietary fat absorption by approximately 30%, promotes weight loss, and may reduce the risk of developing impaired glucose tolerance and type 2 diabetes in obese subjects. OBJECTIVE: To test the hypothesis that orlistat combined with dietary intervention improves glucose tolerance status and prevents worsening of diabetes status more effectively than placebo. METHODS: We pooled data from 675 obese (body mass index, 30-43 kg/m2) adults at 39 US and European research centers in 3 randomized, double-blind, placebo-controlled multicenter clinical trials. Subjects received placebo plus a low-energy diet during a 4-week lead-in period. On study day 1, the diet was continued, and subjects were randomized to receive placebo 3 times a day (n=316) or treatment with orlistat, 120 mg 3 times a day (n=359), for 104 weeks. A standard 3-hour oral glucose tolerance test was performed on day 1 and at the end of treatment. MAIN OUTCOME MEASURES: The categorical assessment of glucose tolerance status (normal, impaired, diabetic) and changes in status from randomization to end of treatment were the primary efficacy measures. The secondary measures were fasting and postchallenge glucose and insulin levels. RESULTS: The mean length of follow-up was 582 days. Subjects who were treated with orlistat lost more weight (mean +/- SEM, 6.72 +/- 0.41 kg from initial weight) than subjects who received placebo (3.79+/-0.38 kg; P<.001). A smaller percentage of subjects with impaired glucose tolerance at baseline progressed to diabetic status in the orlistat (3.0%) vs placebo (7.6%) group. Conversely, among subjects with impaired glucose tolerance at baseline, glucose levels normalized in more subjects after orlistat treatment (71.6%) vs placebo (49.1%; P=.04). CONCLUSIONS: The addition of orlistat to a conventional weight loss regimen significantly improved oral glucose tolerance and diminished the rate of progression to the development of impaired glucose tolerance and type 2 diabetes.

Comparison of indirect calorimetric measurements of resting energy expenditure with a ventilated hood, face mask, and mouthpiece.

This study compared three techniques for indirect calorimetric measurement of resting energy expenditure: ventilated canopy, face mask, mouthpiece plus noseclips. A total of 18 healthy men and women underwent all three measurement techniques in three consecutive 20-min measurement periods in a Latin square design. No significant effects were found for either period or method with respect to oxygen consumption, respiratory exchange ratio, and caloric expenditure. Oxygen consumption was (mean +/- SD) 250 +/- 45, 251 +/- 47, and 254 +/- 49 mL/min for hood, mask, and mouthpiece, respectively (ns). The respiratory exchange ratio was lower for the hood (0.809 +/- 0.051) than mask (0.837 +/- 0.043) and mouthpiece (0.847 +/- 0.045) but this difference was not statistically significant (p = 0.07). Calculated caloric expenditure was 1.20 +/- 0.22, 1.21 +/- 0.22, and 1.23 +/- 0.23 kcal/min for hood, mask, and mouthpiece, respectively (ns). Thus, in healthy individuals similar results are obtained by the three methods and the face mask and mouthpiece are acceptable alternatives to the ventilated hood for estimation of resting energy expenditure.

Use of bioelectrical impedance analysis measurements as an evaluation for participating in sports.

Bioelectrical impedance analysis (BIA) has potential in the area of sports and exercise as a method for evaluating body composition in groups of athletes. BIA probably holds less promise for detecting small changes in percentage fat within an individual. Available data in athletes have indicated an urgent need to control for testing conditions such as hydration, temperature, glycogen stores, and preceding diet and exercise. There are almost no data available for female athletes, but acceptable results have been reported in males when conditions are well controlled. There is, however, a tendency for BIA to overestimate percentage body fat, and more so in African American athletes. BIA is also potentially useful for assessing the hydration status in wrestlers, but it is advisable to use untransformed BIA measurements rather than to convert resistance measurements to body fat because of the questionable hydration status in these athletes. Untransformed results are potentially useful in evaluating the clinical status of athletes at risk for abnormal hydration because of extreme dieting practices.

Thermic effect of food during graded exercise in normal weight and obese men.

The thermic effect of food during incremental cycle ergometer exercise was compared in six normal weight and six obese men (mean +/- SEM 104 +/- 5% and 160 +/- 11% ideal body weight, respectively). Graded exercise tests were performed after a 12-h fast and 60 min after the start of a 910 kcal mixed meal, on separate days. The thermic of food during exercise, which is the fed minus the fasting oxygen consumption (VO2), was significantly greater for the normal than the obese men at submaximal intensities from O (unloaded cycling) to 100 W (p less than 0.05). The mean slope of the regressions of VO2 (ml . min-1) on power output (W), which reflects the rate of increase in energy expended relative to increases in external work performed, did not differ significantly between the fed and fasting conditions for either group, but the mean (+/- SEM) intercept was significantly higher for the normal, but not the obese men, in the fed than the fasting state (599 +/- 53 versus 497 +/- 47 ml O2 . min-1 for the normal men and 819 +/- 126 versus 821 +/- 145 ml O2 . min-1 for the obese men). These results indicate that the thermic effect of food during exercise, which is virtually absent in the obese men, does not increase significantly across submaximal power outputs for the normal men and therefore does not reflect a significant reduction in efficiency.

Energy depot replenishment in rats during refeeding after fasting: effect of exercise.

The effect of progressive moderate exercise on body weight gain, visceral and muscle protein stores, and thyroid hormone levels during an 8-day refeeding period after 65 h of starvation was studied in 2-month-old male Sprague-Dawley rats. Twenty-four animals were divided into three groups and acclimated for 5 days while being fed with ordinary Purina Chow. After the fasting phase, a group of rats was killed in order to provide base-line information concerning fasting-induced changes in body composition; a sedentary group was fed Purina Chow ad libitum; and a treadmill-exercised group was pair fed with the sedentary rats. During the refeeding phase, the exercised animals regained significantly less weight than the sedentary animals (p less than 0.001), but the two groups did not differ significantly with respect to visceral, muscle, eviscerated carcass, and skin protein. Total body fat content was lower in the exercised than the sedentary group. The thyroid hormone levels were not significantly different for the two refed groups. These results indicate that exercise during refeeding may alter the pattern of body weight gain during refeeding after fasting such that the replenishment of adipose tissue stores is reduced without compromising the restoration and growth of lean tissue.

Comparison of thermic effects of constant and relative caloric loads in lean and obese men.

Controversy regarding defective thermic effect of food (TEF) in obesity might be related to differences among studies in the caloric loads. To clarify further the role of blunted thermogenesis in obesity, responses to the same absolute caloric load (720 kcal) and a relative load, which was 35% of each subject's resting metabolic rate (RMR), were compared in 11 lean (L) and 11 obese (O) men. The relative load was slightly larger for O than L (752 +/- 27 vs 683 +/- 21 kcal; means +/- SEM, NS). TEF, calculated as 3-h postprandial minus fasting RMR, was greater for L than O for both the 720-kcal (69 +/- 4 vs 31 +/- 3 kcal/3 h, p less than 0.01) and relative loads (64 +/- 4 vs 37 +/- 3 kcal/3 h, p less than 0.01). For L, TEF was greater for the 720-kcal load than for the relative load whereas for O, TEF was greater for the relative than for the 720-kcal meal. However, expressed as a percent of the calories ingested, TEF for the absolute and relative meals was identical for each group, in both cases lower for O (4.2 +/- 0.4% vs. 4.7 +/- 0.3%) than for L (9.7 +/- 0.4% vs 9.3 +/- 0.8%); p less than 0.01. These results demonstrate the impact on thermogenesis of the basis on which the meal is dosed and provide further evidence for defective thermogenesis in obesity.

TOBEC methodology for body composition assessment: a cross-validation study.

The accuracy of prediction equations for estimating lean body mass (LBM) from total-body electrical conductivity (TOBEC) was examined by cross-validation. Two samples of adults, aged 18-35 yr, were drawn from separate geographic locations. LBM was determined by densitometry and TOBEC was measured with TOBEC II instrument. LBM and TOBEC were highly correlated in both samples (r = 0.96 and 0.97). Cross-validation of LBM prediction equations was accomplished by exchanging equations and comparing predicted LBM values. There was a mean difference of 0.974 kg LBM between the two equations (p less than 0.0001). Thus, data from 157 subjects were pooled and one equation was developed that incorporated height (cm), sex (males = 0, females = 1), and the zero-, first-, and second-order Fourier coefficients (FC0, FC1, and FC2) of the TOBEC phase value: LBM, kg = -36.410 + (-1.324 X sex) + (0.01185 X (FC1(0.5)xht)) + (12.347 X FC2(0.5)) + (0.0627 X FC0)-(0.9232 X FC2) This equation, developed from 157 subjects, accounted for 96% of the variability in LBM and had a standard error of estimate of 2.17 kg LBM.

Lean body mass estimation by bioelectrical impedance analysis: a four-site cross-validation study.

This study validated further the bioelectrical impedance analysis (BIA) method for body composition estimation. At four laboratories densitometrically-determined lean body mass (LBMd) was compared with BIA in 1567 adults (1069 men, 498 women) aged 17-62 y and with 3-56% body fat. Equations for predicting LBMd from resistance measured by BIA, height, weight, and age were obtained for the men and women. Application of each equation to the data from the other labs yielded small reductions in R values and small increases in SEEs. Some regression coefficients differed among labs but these differences were eliminated after adjustment for differences among labs in the subjects' body fatness. All data were pooled to derive fatness-specific equations for predicting LBMd: the resulting R values ranged from 0.907 to 0.952 with SEEs of 1.97-3.03 kg. These results confirm the validity of BIA and indicate that the precision of predicting LBM from impedance can be enhanced by sex- and fatness-specific equations.

Estimation of extracellular and total body water by multiple-frequency bioelectrical-impedance measurement.

This study evaluated a new technology of bioelectrical-impedance (BI) measurement that makes use of multiple frequencies (5, 50, and 100 kHz) for estimation of extracellular and total body water. In 36 healthy males, resistance and reactance at three frequencies were compared with extra-cellular water (ECW) and total body water (TBW) determined by isotope dilution. ECW was best predicted by resistance measured at 5 kHz, corrected for height and weight (R = 0.930, SEE = 1.94 L) whereas TBW was best predicted by resistance at 100 kHZ and weight (R = 0.947, SEE = 2.64 L). Cross-validation analysis on two randomly selected subsets (n = 18 each) indicated that the prediction equations were reproducible and valid. Thus, BI at dual frequencies is valid for determination of body-water compartments and may be useful in the nutritional assessment of patients in whom body water and hydration is of clinical concern.

Acute effects of exercise on food intake in obese and nonobese women.

The animal model of exercise-induced anorexia was employed in humans to develop a laboratory paradigm for studying the acute effect of exercise on food intake. Each of nine obese and nine nonobese women exercised either strenuously (90 W) or moderately (30 W) on a cycle ergometer for 40 min or rested in the laboratory on each of 3 nonconsecutive days. Intake of a liquefied test meal (1.04 kcal/g) eaten 15 min after exercise was significantly less after the strenuous (620 g) than after the moderate (754 g) exercise in the nonobese women but was no different after the two conditions (532 g after strenuous, 581 g after moderate) in the obese women. Heart rate and energy expenditure were increased in proportion to the exercise by the same amount in both groups. The results demonstrate for the first time that food intake is reduced immediately after strenuous exercise in nonobese women, as it is in animals, and validate the feasibility of this laboratory paradigm.

Levels of serum sex hormones and risk factors for coronary heart disease in exercise-trained men.

On the basis of previous findings, it has been hypothesized that hyperestrogenemia may be the major predisposing factor for coronary heart disease and that an elevation in the estradiol-to-testosterone ratio, or a closely related hormonal alteration, may cause the expression of risk factors for coronary heart disease. The present study was carried out to investigate whether exercise training, which has been reported to reduce risk factors for coronary heart disease, affects the serum sex hormone levels. The serum sex hormone levels, established risk factors for coronary heart disease, and physical fitness were measured in 10 men who had undergone at least six months of intensive exercise training and in 10 sedentary men of similar age. Despite evidence for a strikingly higher level of physical fitness and a lower level of risk factors in the trained group, no significant difference in mean serum estradiol level was found. Nor did three subjects from the sedentary group show a decrease in estradiol level after three to four months of exercise training. The mean estradiol-to-testosterone ratio, however, was significantly lower in the trained group and might account for the lower level of risk factors in that group. If the hypothesis is correct, exercise training may decrease established risk factors for coronary heart disease without decreasing the risk of coronary heart disease.

Serum thyroglobulin and iodine-131 whole-body scan in the diagnosis and assessment of treatment for metastatic differentiated thyroid carcinoma.

UNLABELLED: Because of the limitations of periodic 131I whole-body scans, including suspension of substitution therapy, questionable sensitivity and low yield in detecting metastases in patients who have undergone thyroidectomy, serum thyroglobulin and 131I whole-body scans were evaluated for sensitivity in detecting local, regional or distant metastases in 261 patients with differentiated thyroid carcinoma after total thyroidectomy and ablation. METHODS: A noncompetitive immunoradiometric assay was used for serum thyroglobulin determination. An 131I whole-body scan was obtained after replacement therapy had been suspended for 6 wk or when TSH reached levels higher than 50 microU/ml. In patients who underwent radiological procedures with iodinated contrast media, the waiting period before the 131I whole-body scan was no less than 10 wk. RESULTS: Of the 58 patients with proven metastases who were followed for 12 yr (mean 7 +/- 3.3 yr), 51 (88.4%) had high serum thyroglobulin assays performed while under full replacement therapy and 32 (55%) showed clear 131I whole-body scan localization. There were no instances of positive whole-body scans and negative serum thyroglobulin. CONCLUSION: In patients treated with 131I, serum thyroglobulin assay was an excellent method to assess treatment. Patients with metastatic disease and negative whole-body scans with or without serum thyroglobulin exhibited a trend toward higher mortality. This trend may also indicate that the lack of 131I trapping and low thyroglobulin is a sign of metabolic dedifferentiation of otherwise histologically differentiated thyroid tumors.