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Biomedical subjects

S N Steen

Publications and source records attributed to S N Steen.

At least 19 recordsLinked to original sources
PubMed1992

Disparate effects of weight loss on insulin sensitivity and erythrocyte sodium-lithium countertransport activity.

Previous investigations have demonstrated an association between impaired insulin sensitivity and elevated erythrocyte sodium-lithium countertransport (Na(+)-Li+ CT) activity. It has been speculated that insulin resistance and endogenous hyperinsulinemia are causally related to the development of elevated Na(+)-Li+ CT activity. To test this hypothesis, we measured insulin sensitivity (euglycemic insulin clamp technique) and Na(+)-Li+ CT activity in eight obese women before (weight = 102 +/- 5 kg) and after (weight = 88 +/- 5 kg; P < .001) a 10 week weight reduction program. Maximal velocity of Na(+)-Li+ CT activity did not change (0.50 +/- 0.09 v 0.49 +/- 0.10 mmol/L red blood cells/h; P = NS) despite the significant improvement in insulin sensitivity (73 +/- 12 vs 110 +/- 7 mg/m2/min; P < .0025) and reduction in fasting insulin levels (17 +/- 2 v 10 +/- 2 microU/mL; P < .05) that accompanied weight loss. These results suggest that insulin resistance and hyperinsulinemia are not linked pathophysiologically to the development of elevated Na(+)-Li+ CT activity.

Adult↗
PubMed1991

Precontest strategies of a male bodybuilder.

The dietary strategies of a 25-year-old bodybuilder were studied as he prepared for a contest. Food records were kept over a 6-month period that included the off-season, weight reduction phase, and week of a contest. Mean caloric intake during the off-season was 4,193 kcal (49 kcal/kg). Average intake per kg body weight was 8.7 g/kg carbohydrate and 2.8 g/kg protein. During the weight reduction phase of training, mean caloric intake was 3,020 kcal (37 kcal/kg). Carbohydrate intake averaged 6.1 g/kg and protein averaged 2.7 g/kg. The RDA was met for all micronutrients without any need for supplementation. Beginning at 3 weeks before the contest, dietary intake changed dramatically and haddock, rice, or potato were eaten every 2 hours. Protein intake averaged 4 g/kg. Carbo-loading was practiced the week precontest to enhance muscularity. During all phases the subject used anabolic steroids and consumed various supplements. During the off-season he took a high potency multivitamin/multimineral daily and 60-100 grams of amino acids when "needed." As the competition drew closer, numerous additional supplements were taken. In light of these many unhealthy practices, alternative strategies should be negotiated with the athlete that are realistic, and changes should be implemented slowly.

Adult↗
PubMed1990

Eating behaviors, weight loss methods, and nutrition practices among high school wrestlers.

Wrestlers lose weight frequently, using rapid weight reduction methods in order to qualify for a certain weight classification. Under these conditions, the potential for developing eating disorders seems apparent. A questionnaire was used to evaluate binge eating and bulimic behaviors, nutrition practices, and weight loss methods in 716 wrestlers. Subjects lost 4.0 kg, on average, to certify, and cycled (lost and regained) 2.3 kg weekly. Two-thirds gained weight in the postseason. The most frequently used weight loss methods included increased exercise, food restriction, gradual dieting, and heated wrestling rooms. Subjects relied primarily on coaches and fellow wrestlers for sources of weight management. Using symptom severity levels by Hawkins and Clement (1980) and the Diagnostic and Statistical Manual of Mental Disorders (3rd ed.; DSM-III; American Psychiatric Association, 1980) criteria, 2.8% of subjects were classified as bulimic; 1.4% using DSM-III-R (3rd ed.; rev; American Psychiatric Association, 1987); and 1.4% met both DSM-III and DSM-III-R. There were significant differences between the diagnostic (DG) and nondiagnostic groups (NDG) in weight lost to certify, weekly weight fluctuation, postseason weight gain, and severity of binge eating. The DG used fasting, food and fluid restriction, dehydration methods, and laxatives significantly more often to promote weight loss. They also experienced significantly more negative feelings during and following binging. Implications for nursing research and clinical practice are also discussed.

Adolescent↗
PubMed1990

Patterns of weight loss and regain in wrestlers: has the tradition changed?

To assess current weight loss practices in wrestlers, 63 college wrestlers and 368 high school wrestlers completed a questionnaire that examined the frequency and magnitude of weight loss, weight control methods, emotions associated with weight loss, dieting patterns, and preoccupation with food. Clear patterns emerged showing frequent, rapid, and large weight loss and regain cycles. Of the college wrestlers, 41% reported weight fluctuations of 5.0-9.1 kg each week of the season. For the high school wrestlers, 23% lost 2.7-4.5 kg weekly. In the college cohort, 35% lost 0.5-4.5 kg over 100 times in their life, and 22% had lost 5.0-9.1 kg between 21 and 50 times in their life. Of the high school wrestlers, 42% had already lost 5.0-9.1 kg 1-5 times in their life. A variety of aggressive methods wer used to lose weight including dehydration, food restriction, fasting, and, for a few, vomiting, laxatives, and diuretics. "Making weight" was associated with fatigue, anger, and anxiety. Thirty to forty percent of the wrestlers, at both the high school and college level, reported being preoccupied with food and eating out of control after a match. The tradition of "making weight" still appears to be integral to wrestling. The potential physiological, psychological, and health consequences of these practices merit further attention.

Adolescent↗
PubMed1990

Efficacy of oral mexiletine therapy at a 12-h dosage interval.

The antiarrhythmic effectiveness and safety of 12-h oral administration of mexiletine were evaluated in adult outpatients with a baseline hourly rate of PVCs of 30 or higher who had initially shown at least a 50 percent reduction of this rate when treated with mexiletine at an 8-h dosage interval. Doses were titrated on the basis of 24-h Holter monitoring for both 8- and 12-h intervals. Seventeen of 26 patients showed PVC reductions after 8-h treatment. Fifteen of these 17 patients reached the goal reduction of greater than or equal to 50 percent in the hourly PCV rate with 12-h dosing. Hour-by-hour analysis disclosed a consistent degree of PVC suppression throughout both 8- and 12-h dose intervals. No increase in the incidence of adverse effects was associated with conversion to the 12-h regimen.

Administration, Oral↗
PubMed1990

[Does flumazenil antagonize the anesthetic effect of ketamine, etomidate or thiopental?].

The effect of flumazenil, a benzodiazepine antagonist, was assessed in a random, double-blind clinical study in which each of the four groups of surgical outpatients comprising 20 in each was given either ketamine 100 mg (K), etomidate 20 mg (E), thiopental 300 mg (T) or flunitrazepam 4 mg (F) for induction of anesthesia. On emergence, patients in each group were randomly given 2cc of either 2 coded solutions, one of which contained 0.2 mg flumazenil and the other of which was normal saline. Following injection of coded solution, all patients were assessed at 0, 5, 15, 30, 60 and 120 min for wakefulness. All 10 patients of group F who received flumazenil were alert and able to recall at 5 min, whereas in group T this was noted from 15 to 30 min. Patients of group E and K responded alike in a manner as of those who received normal saline placebo with onset of wakefulness at 30 and 60 min respectively. These results confirm that flumazenil antagonizes flunitrazepam (within 5 min) and also indicate that the antagonizing effect occurs 30 min following injection for thiopental, suggestive of some cross-reactivity between these two drugs.

Adult↗
PubMed1989

Ultrasonic tissue characterization of acute canine myocardial infarction.

This study assessed changes in left ventricular texture on two-dimensional (2-D) echocardiography after experimental myocardial infarction. In 13 dogs, the left anterior descending coronary artery (LAD) was occluded for 3 h, followed by 1 h of reperfusion and sacrifice. Two-dimensional echocardiography was performed pre-LAD occlusion, 3 h post occlusion and 1 h after reperfusion by placing a 5 MHz transducer on the chest wall. After sacrifice, triphenyltetrazolium chloride staining was performed on 1 cm thick left ventricular cross-sectional slices. Five dogs served as controls (shams). Two-dimensional echocardiograms were digitized and in the region of left ventricular asynergy (area of myocardial infarction), and adjacent normal area, the mean pixel intensities (+/- SD) were calculated. There was no significant change in the mean pixel intensity from 0 through 4 h in the lateral (22.8 +/- 1.3 and 23.4 +/- 1.8) and anteroseptal (23.2 +/- 1.9 and 22.6 +/- 1.9) regions in sham operated dogs. In dogs undergoing LAD occlusion, the mean pixel intensity from the pre- to post occlusion period showed no significant change in the lateral (normal) area, 24.4 +/- 2.7 versus 24.7 +/- 2.9. In the area of wall motion abnormality (area of myocardial infarction) the mean pixel intensity increased from 25.4 +/- 2.7 to 33.7 +/- 4.5, P less than 0.01. There was no significant change in the mean pixel intensity between the 3 h post occlusion and post reperfusion period in either the lateral (normal) or anteroseptal areas of the left ventricle. The area of left ventricular asynergy corresponded to the area of myocardial infarction on triphenyltetrazolium chloride stain.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

[Comparative study of the antagonizing effect to flunitrazepam between Ro 15-1788 and physostigmine].

In a double blind, randomized, placebo-controlled study, thirty patients who had received flunitrazepam during operation were divided into three groups. At the end of surgery, one group was given a placebo, one group was given Ro 15-1788 (Benzodiazepine antagonist) and a third group was given physostigmine. Each group was assessed at the end of 5 minutes, 15 minutes, 30 minutes 60 minutes and 120 minutes for alertness/sedation, recall, recognition and motor coordination. At the end of 5 and 15 minutes, the patients who had received Ro 15-1788 showed a statistically significant difference in alertness/sedation from those in the other two groups (p less than 0.01). This group also showed a statistically significant difference in motor coordination at the end of 5 minutes (p less than 0.05). There was no significant difference in recognition or recall at anytime. Physostigmine showed no significant difference change from the control group at anytime in every aspect. In conclusion, Ro 15-1788 is an effective antagonist to the alertness/sedation of flunitrazepam, but physostigmine is not.

Adult↗
PubMed1988

Metabolic effects of repeated weight loss and regain in adolescent wrestlers.

This study examined resting metabolic rate in adolescent wrestlers to test the hypothesis that repeated cycles of weight loss and regain would be associated with reduced energy requirements. Energy restriction lowers resting metabolic rate in normal-weight and obese persons. Repeated cycles of weight loss and regain can increase food efficiency, defined as the degree of weight change per unit of food intake, in animals. Many wrestlers lose weight repeatedly as they "cut weight" for matches. This cycle of weight loss and regain may affect their resting metabolism. Twenty-seven wrestlers were classified as cyclers or non-cyclers based on their weight loss history. Resting metabolic rate was measured using indirect calorimetry and body composition was evaluated using six skinfolds. Cyclers and noncyclers did not differ in age, weight, height, surface area, lean body mass, or percent body fat. Cyclers had a significantly lower mean resting metabolic rate than noncyclers (154.6 vs 177.2 kJ/m2/h) (4.6 vs 5.5 kJ per kilogram of lean body mass per hour). There was a 14% difference between the cyclers and the noncyclers in resting energy expenditure (6631.8 vs 7702.8 kJ/d). Weight cycling in wrestlers appears to be associated with a lowered resting metabolic rate.

Adolescent↗
PubMed1988

Influence of nitrous oxide on rat skin allograft.

Adult male Lewis/f Mai rats underwent skin allografts and the time for complete loss of the graft was compared among different groups treated with different methods. The rats were exposed in isolation chambers to an atmosphere of either room air (control groups I and IV for nitrous oxide-exposed groups, 20% and 40%, respectively); or an atmosphere of oxygen supplemented respectively with 20% and 40% nitrous oxide (the balance being nitrogen) continuously after transplant surgery (Groups II and V respectively); or 48 hours prior to transplantation and with air exposure only after surgery (Groups III or VI respectively). Results indicated that nitrous oxide-exposed rats had significantly prolonged skin allograft survival.

Adjuvants, Immunologic↗
PubMed1987

Weight regulation practices in athletes: analysis of metabolic and health effects.

Athletes engage in a number of dietary and weight control practices which may influence metabolism, health, and performance. This paper reviews the literature on these factors with special emphasis on athletes who show large, frequent, and rapid fluctuations in weight (wrestlers) and athletes who maintain low weight and low percent body fat (e.g., distance runners, gymnasts, and figure skaters). A theory is presented which relates these weight patterns and the accompanying dietary habits to changes in body composition, metabolism, metabolic activity of adipose tissue, and the distribution of body fat. Changes in these physiological variables may be manifested in enhanced food efficiency (weight as a function of caloric intake) as the body seeks to protect and replenish its energy stores. This may explain the surprisingly low caloric intakes of some athletes. The health status of the athlete is a concern in this regard because there may be changes in fat distribution, risk factors for cardiovascular disease, and hormonal factors associated with reproductive functioning in both females and males. Amenorrhea in female athletes may be mediated at least in part by regional fat distribution; depletion of femoral fat depots (lactational energy reserves) may be the stimulus for cessation or disruption of menses.

Adipose Tissue↗
PubMed1985

Paediatric anaesthetic management with the aid of a computer.

A computer program has been developed to assist in the preparation of proper drug and anaesthetic doses for children. An individualized reference sheet containing the doses of the more commonly used drugs for the induction and maintenance of anaesthesia, fluid requirements, blood volume information, ventilatory variables, estimated endotracheal tube sizes and emergency drug doses constitutes the output of this program. The importance of such a computer program in improving paediatric anaesthetic management is discussed.

Adolescent↗
PubMed1984

Double-blind, placebo-controlled trial of propranolol given once, twice and four times daily in stable angina pectoris: a multicenter study using serial exercise testing.

To determine if propranolol given twice daily (b.i.d.) or once daily (q.d.) was as effective as 4 times daily (q.i.d.) for treatment of stable angina pectoris, 78 patients with exercise-induced ST depression of 1.5 mm were randomized to q.i.d., b.i.d., q.d. and placebo groups. All patients received 5 tablets per day, and propranolol groups received 80, 160 and 320 mg/day on successive weeks. At weekly visits, patients underwent treadmill exercise testing before the 8:00 AM dose and at 2 and 9 hours afterward. Exercise duration (seconds) was significantly improved at the final visit compared with baseline by b.i.d. (120 +/- 36 [mean +/-] standard error of the mean p less than 0.001 n = 18) and q.i.d. (100 +/- 37, p less than 0.01; n = 17) regimens, but not by the q.d. (30 +/- 33; n = 18) and placebo regimens (27 +/- 37; n = 17). There was a significant decrease from baseline in the magnitude of ST depression at the final visit, measured at maximal common exercise duration in b.i.d. (-0.96 +/- 0.20 mm, p less than 0.001), q.i.d. (-0.84 +/- 0.20 mm, p less than 0.01) and q.d. (-0.58 +/- 0.18 mm, p less than 0.05) groups, but not in the placebo group (0.03 +/- 0.2 mm). Hourly heart rate by Holter was reduced in all 3 propranolol groups; however, the mean serum propranolol level was significantly lower just before the first dose with q.d. group (56 +/- 20 ng/ml) compared with b.i.d. and q.i.d. groups (146 +/- 22 and 119 +/- 28 ng/ml) with 320 mg/day (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1980

Long-term management of rheumatoid arthritis with disalcid.

Disalcid, a salicylic acid pro-drug, was administered for 3 months to eighteen rheumatoid arthritis patients, with monitoring of clinical response, side-effects and laboratory changes. The drug produced a satisfactory to excellent response in fourteen patients and was unsatisfactory in four. Gastric side-effects occurred in three patients and allergic reaction in one. Serum salicylic acid concentrations were adequately maintained between 15 to 25 mg/100 ml. Funduscopic monitoring revealed one retinal defect in a patient with hypertension. Laboratory examinations, blood chemistry and urine analyses remained within normal limits during the 12-week trial.

Adult↗
PubMed1978

Butorphanol and promethazine as pre-anaesthetic medication.

An open evaluation of a combination of butorphanol (1 or 2 mg), promethazine (25 or 50 mg) and atropine (0.5 mg) in 109 adult consenting patients was carried out to determine their safety and efficacy for preanaesthetic medication. All patients were kept under direct surveillance from before intramuscular medication until they were in satisfactory condition post-operatively for discharge from the recovery room. The medications employed did not disturb the blood pressure, pulse rate or respiration rate in any of the patients. None complained of nausea or dizziness while only one was slightly excited. Sedation was rated as satisfactory in 97 per cent, and 90 per cent were free of apprehension. In addition, global evaluation of the premedication by the investigator was rated good to excellent in 99 per cent of the patients. On the basis of these observations, the combination of butorphanol with promethazine and atropine appears safe and useful for pre-anaesthetic medication.

Adolescent↗