Biomedical subjects
Publications and source records attributed to D L Elliot.
A 27-year-old recreational jogger developed gross hematuria following a 2-mile run. Evaluation revealed a transitional cell carcinoma of the bladder. Etiologies for pigmenturia and the pathogenesis of exertional hematuria are reviewed. The need to exclude other causes of hematuria before attributing the finding to exercise is emphasized.
The opinions (level of agreement) of high school varsity football players with regard to reported effects of anabolic steroids were assessed before and after two different education interventions. Lectures and handouts of a balanced education program (potential risks and benefits) were compared with a risks-only (negative or "scare tactics") presentation, in a controlled manner. Those receiving the balanced review significantly increased their agreement with 5 of 10 targeted adverse effects, while no change occurred for any risks among those taught by the negative intervention. A teaching model that only emphasizes the untoward consequences of anabolic steroids is ineffective, even in the short-term. A balanced education approach can improve understanding of the potential adverse effects of these drugs. Additional strategies may be required to change young athletes' attitudes toward anabolic androgenic steroid use.
A 28-yr-old, female marathon and "fitness" runner presented with leg swelling, fatigue, and loss of endurance. She was running an hour or more daily in addition to regular biking and swimming. She was an instructor in a fitness center. For 2 months prior to her leg swelling, she had increased fatigue and decreased exercise tolerance. She had been seen previously for a slow healing hamstring strain. She had not had a menstrual period for over 2 yr and had refused evaluation. She admitted to very low dietary intake, which she had always denied. She was worried about her body fat. She denied recent blood loss, diuretic or cathartic use, and induced vomiting. She appeared malnourished, pale, and older than her stated age. Her weight was 41.4 kg. Her blood pressure was 90/60, and her pulse was 100 per minute. She had pitting edema of the lower extremities to the knees. The diagnosis of anorexia nervosa was made and will be discussed.
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OBJECTIVE: To test the hypotheses that obese adolescents have a lower resting metabolic rate and less aerobic endurance than their nonobese siblings. DESIGN: Case-referent study of obese and nonobese siblings from the same kindred. SETTING: Tertiary referral center. PARTICIPANTS: Telephone screening of community volunteers resulted in a consecutive sample of 16 kindreds. Obese and nonobese siblings were similar in age, height, and pubertal status. Significantly more female subjects were in the obese group (p less than 0.01). MEASUREMENTS AND MAIN RESULTS: Body composition studies revealed that the obese siblings had higher body fat (p less than 0.001) but that fat-free mass was similar to that of the lean siblings. Resting metabolic rates determined by indirect calorimetry for the obese and nonobese pairs did not differ. Although the obese siblings appeared less fit when maximal oxygen consumption was measured in relation to total weight, maximal oxygen consumption did not differ when values were standardized for fat-free mass. CONCLUSIONS: The obese adolescents did not have a reduced resting metabolic rate. As in adults, the relationship between resting metabolic rate and fat-free mass was similar for obese and nonobese children and adolescents. Any decreased sport participation by the obese siblings was not due to inherent reductions in aerobic capacity.
To assess potential long-term effects of weight loss on resting metabolic rate (RMR), the RMRs of seven obese women were measured by indirect calorimetry before weight loss, during a protein-sparing modified fast, and for 2 mo while at a stable reduced weight. Body composition was also determined at each interval. RMR significantly decreased 22% (p less than 0.01) with initiation of the modified fast. RMR values during the modified fast and during the maintenance diet at stable reduced weight were not different and all were significantly lower than the prediet RMR. Loss of lean tissue could not account for the decrease because changes in RMR per fat-free mass paralleled the total RMR reduction. A sustained decrement in RMR accompanied weight loss and persisted for greater than or equal to 8 wk despite increased caloric consumption and body weight stabilization.
Exertional muscle pain and fatigue are common complaints; some patients with these symptoms have a metabolic myopathy. We have performed graded exercise testing with analysis of expired ventilation on 13 individuals with various kinds of metabolic myopathies. Their results differed from normal and reflected the underlying biochemical abnormality. Patients with disorders of the mitochondrial electron transport chain demonstrated marked limitations in aerobic metabolism and a greatly reduced maximum oxygen consumption. During intense exertion, normal individuals increase carbon dioxide generation due to buffering of lactic acid. This did not occur in patients with McArdle disease, in whom the respiratory exchange ratio (carbon dioxide production/oxygen consumption) did not rise above 1.0 at maximum exercise. These results indicated a deficit in anaerobic metabolism. Pyruvate dehydrogenase complex allows pyruvate produced from carbohydrate metabolism to enter the citric acid cycle. Patients with this enzyme deficiency showed an initially normal pattern followed by an abrupt cessation in carbohydrate dependent aerobic metabolism at higher work loads. During high-intensity exercise, progressive anaerobic metabolism was not accompanied by additional oxygen consumption. Finally, results from a patient with carnitine palmitoyl transferase deficiency revealed an early dependence on carbohydrate metabolism. The ventilatory threshold occurred at a low percentage of maximal oxygen consumption, reflecting the limited availability of lipid substrates for aerobic metabolism. Detection of some muscle metabolic abnormalities can be made on small biopsy specimens. However, definitive diagnosis of the defect nearly always requires studies on fresh or frozen muscle tissue obtained by an open biopsy. The decision on how the tissue should be processed and which metabolic studies should be performed frequently needs to be made before the biopsy is obtained. Thus, a noninvasive method to initially characterize patients with potential metabolic disorders is useful. Exercise testing with expired gas analysis can indicate the presence of a metabolic myopathy and results can then be used to direct the appropriate biochemical evaluations.
We measured the metabolic rate by indirect calorimetry for 90 minutes following exercise in six healthy individuals. Ten and 30 minutes of cycling at 80% of maximal intensity produced comparable increases in the resting metabolic rate, (37% and 32%, respectively) immediately after exercise. However, by 30 minutes following exertion, the metabolic rate was not different from control values. The total additional caloric use during the 90 minutes of recovery was similar for the two exercise durations, and the mean increment in recovery energy expenditure was 11.4 +/- 7.1 kcals. The majority of caloric use with exercise is during the activity. Recovery energy expenditure following usual aerobic training results in only a minor contribution to total energy use.
Guidelines for training heart rate (HR) during aerobic exercise are often determined by predictive formulas. Measurement of the heart rate at ventilatory threshold (VT) by expired gas analysis provides a direct index of the upper limits of conditioning intensity. We evaluated 115 nonsmoking, healthy adults with measurement of peak oxygen uptake to classify groups as low- (n = 45), average-(n = 45), and high (n = 25) -fitness. Heart rate at VT was compared with the approximate midpoint (77 percent) of recommended training intensity as estimated by the Karvonen equation, predicted maximal (220-age), and measured maximal HR formulas. No significant difference among the various HR formulas at 77 percent and HR at VT were found for high-fitness individuals. Among the low- and average-fitness groups, the Karvonen formula at 77 percent was significantly higher (p less than 0.001) than HR at ventilatory threshold. Predicted and measured maximal HR at 77 percent were not above the VT among the low- and average-fitness individuals and are appropriate for training intensity. However, the Karvonen formula appears to overestimate heart rate intensity among those of low and average fitness and may be excessive for these groups.
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Cardiac deaths are more likely to be unanticipated than cancer deaths by patients, their families, and their physicians. We hypothesized that differing physician attitudes toward dying patients may affect the degree of expectation of death. To evaluate differences in attitudes and behaviors among subspecialists, we surveyed a randomly selected population of California subspecialists; 44 of 136 (32%) of cardiologists and 91 of 167 (55%) of oncologists responded. Oncologists experienced three times as many deaths as cardiologists and reported having discussed code status more often with patients who died. Cardiologists' patients' deaths were more often unexpected and occurred more frequently in intensive care units. In addition, their patients were more likely to be given cardiopulmonary resuscitation. Oncologists reported being more comfortable dealing with dying patients and having less desire to avoid them. When presented with patient scenarios, however, cardiologists' and oncologists' responses were similar when discussing and estimating prognosis and likelihood of successful therapy.
Effective teaching of physical examination skills requires an evaluation system that can identify trainees who need further instruction. To study the evaluation of physical examination skills by faculty observers and patient instructors, the reliability of their observation of medical students performing a general physical examination was measured. Faculty observers did not reliably evaluate 32% of examination skills. Faculty agreement was lowest when observing components of the head, neck, and abdominal examinations. Patient instructors, with limited faculty training, reliably evaluated 83% of those skills that were reliably assessed by the faculty. These findings demonstrate limitations in the current methods of evaluating performance and point out the need to examine systems of trainee assessment.
We studied the intraocular pressure response to short-term maximal aerobic exertion before and after exercise conditioning in ten healthy sedentary volunteers. Before exercise conditioning, mean intraocular pressure +/- S.E.M. decreased by 5.9 +/- 0.6 mm Hg after short-term maximal aerobic exercise, returning to baseline in a mean of 37 +/- 4 minutes. After four months of exercise conditioning, this ocular hypotensive response was significantly dampened, with a mean intraocular pressure reduction of only 1.6 +/- 0.4 mm Hg after short-term maximal aerobic exercise (P less than .01). Additionally, a significant reduction in baseline intraocular pressure occurred, with a mean intraocular pressure of 14.3 +/- 0.7 mm Hg before exercise conditioning, declining to a mean intraocular pressure of 13 +/- 0.9 mm Hg (P less than .02) after four months of physical training. Exercise conditioning may significantly reduce baseline intraocular pressure and attenuate the hypotensive response to short-term maximal aerobic exercise.
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In a prospective survey for changes in emotions and attitudes of all medical interns of The Oregon Health Sciences University (N = 22) at six intervals during the 1982-1983 academic year, both positive and negative emotional changes were noted. Satisfaction with the decision to become a physician decreased during the period, a change that correlated directly with depression and fatigue and inversely with excitement and importance.
The nutritional aspects of exercise are topics of popular interest, misconception, and active research. In this article, the authors review basic concepts of muscle metabolism; information concerning the role of exercise in weight loss; dietary supplements for athletes, including nutrition for competition; and eating disorders among those performing vigorous exercise.
Preparing the medically compromised patient for surgery requires identifying and treating preoperative risk factors and anticipating postoperative complications. Preoperative evaluation of all patients should include careful screening for bleeding disorders and prior anesthetic complications and assessment of nutritional status. In addition, patients with preexisting cardiac, pulmonary, and endocrine problems must be identified, since these problems represent the greatest risk factors for postoperative complications. Perioperative care is more effective when directed at specific organ systems. Communication among internists, anesthesiologists, and surgeons promotes optimal treatment for surgical patients with medical illness.