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Biomedical subjects

W Fink

Publications and source records attributed to W Fink.

35 records · Page 2Linked to original sources
PubMed1984

Acid-base balance during repeated bouts of exercise: influence of HCO3.

Ten men and one woman were studied before, during, and following five 1-min cycling bouts (100% VO2 max) 1 h after consuming either 0.2 g/kg B.W. of NaHCO3 or a placebo drink (NaCl). The fifth exercise bout was performed until exhaustion and the time recorded to judge the effects of the NaHCO3 drink on performance. Blood samples taken from a forearm vein revealed that the intake of NaHCO3 increased resting pH (7.34 to 7.41), HCO3 (27.5 to 31.0 mM), and base excess (1.1 to 4.6 mM). During and following the exercise, blood pH and HCO3 were always higher (P less than 0.05) in the NaHCO3 than placebo trial. Performance times during the fifth cycling bout averaged 113.5 (SE +/- 12.4) and 160.8 (SE +/- 19.1) s in the NaCl and NaHCO3 trials, respectively. This 42% difference between the means was significant at the 0.01 level. The blood hydrogen ion to lactic acid ratios (nM/mM) measured between each exercise bout and during recovery from the exhaustive fifth bout suggests that the enhanced performance during the NaHCO3 trial was the result of greater buffer capacity. Thigh muscle (vastus lateralis) pH measured immediately before the fifth cycling bout in four of the subjects revealed that the working muscles were less acid in the NaHCO3 trial (pH = 6.81) than during the NaCl treatment (pH = 6.73). Thus, the alkalizing influence of oral HCO3 supports the concept that the hydrogen ion concentration in blood and muscle has a direct influence on performance during repeated, supramaximal exercise.

Acid-Base Equilibrium↗
PubMed1982

Osteoscintimetry--a method of semiquantitative evaluation of skeletal scintigrams by use of profiles and a macro function for computer processing.

A computer macro-program was developed for standardized, semiquantitative measurement of radiotracer uptake. The method uses profiles of selectable length, width, and inclination according to the anatomical structures of the pathological and the corresponding healthy region. The ratio of the two curves is calculated automatically and shown as an 'uptake curve'. The essential use of osteoscintimetry is in the follow-up examination if small changes of regional uptake have to be identified. The profile-technique rather than the ROI-technique was selected, because the main benefit of the profile-technique is that the results of follow-up examinations are comparable to previous examinations with a standard deviation of +/-5%.

Adolescent↗
PubMed1982

Breast carcinoma metastasizing to the cervical esophagus.

Tumor metastasis to the esophagus is rare. While breast carcinoma metastasizing to the thoracic esophagus has been described, there are no reported cases of spread to the cervical esophagus. Two patients, having had mastectomy for breast carcinoma several years previously, presented with cervical esophageal obstruction secondary to metastatic disease. Tumor resection with cervical esophageal reconstruction is advocated for palliation. The details of the history, diagnosis and surgical technique are presented.

Adult↗
PubMed1980

Analysis of volatile N-nitrosamines in mainstream and sidestream smoke from cigarettes by GLC-TEA.

Volatile N-nitrosamines were quantitatively determined in mainstream and sidestream smoke of commercial cigarettes using gas chromatography-thermal energy analysis (GLC-TEA). The smoke was trapped in ascorbic acid solution buffered at pH 4.5 and then extracted with dichloromethane; the organic phase was chromatographed on basic alumina and analyzed by GLC-TEA. The mainstream smoke of 22 different commercial cigarettes from Germany and Switzerland contained between 0.1 and 27 ng dimethylnitrosamine (DMN), 1.5 and 29 ng nitrosopyrrolidine (NPY) and traces of methylethylnitrosamine (MEN). The sidestream smoke of these cigarettes contained between 143 and 415 ng DMN, 3.1 and 27 ng MEN and 28 and 150 ng NPY. In a final experiment we measured the DMN concentration in a sealed experimental chamber as a function of the number of cigarettes smoked and recovered 68-87% of the DMN values found when using the sidestream collection device applied in the other experiments.

Chromatography, Gas↗
PubMed1980

Small bowel volvulus in association with recurrent Crohn's disease.

The concomitant occurrence of Crohn's disease and small bowel volvulus is rare because of the serosal inflammation in the former disease causes adherence of the bowel to adjacent structures. A 61-year old female patient with ileocolitis developed 30 cm. of recurrent Crohn's disease in the ileum proximal to a previous ileosigmoidostomy. Following several episodes of small bowel obstruction she was found to have a small bowel volvulus which progressed to infarction. The possibility of volvulus should be considered in the differential diagnosis of a patient with granulomatous disease because of the danger of gangrene, perforation and peritonitis. Surgery should not be delayed in Crohn's disease if complete obstruction persists more than 24 hours, particularly if ischemia of the bowel cannot be ruled out.

Crohn Disease↗
PubMed1977

Effects of elevated plasma FFA and insulin on muscle glycogen usage during exercise.

Seven men were studied during 30 min of treadmill exercise (approximately 70% VO2 max) to determine the effects of increased availability of plasma free fatty acids (FFA) and elevated plasma insulin on the utilization of muscle glycogen. This elevation of plasma FFA (1.01 mmol/1) with heparin (2,000 units) decreased the rate of muscle glycogen depletion by 40% as compared to the control experiment (FFA = 0.21 mmol/1). The ingestion of 75 g of glucose 45 min before exercise produced a 3.3-fold increase in plasma insulin and a 38% rise in plasma glucose at 0 min of exercise. Subsequent exercise increased muscle glycogen utilization and total carbohydrate (CHO) oxidation 17 and 13%, respectively, when compared to the control trial. This elevation of plasma insulin produced hypoglycemia (less than 3.5 mmol/1) in most subjects throughout the exercise. These data illustrate the regulatory influence of both plasma insulin and FFA on the rate of CHO usage during prolonged severe muscular activity.

Adult↗
PubMed1977

Characteristics of skeletal muscle in competitive cyclists.

Muscle samples from the vastus lateralis and maximal oxygen uptakes were obtained from 22 male and 7 female competitive cyclists. 19 untrained males, and 10 untrained females. Eleven of the 22 male cyclists were designated elite cyclists (Group A) on the basis of their success in national and/or international competition. The remaining 11 male cyclists (Group B) were also trained but had not achieved the same level of competitive success. Significant mean differences (P less than 0.05) between Groups A and B were found for VO2 max (67 and 57 ml/kg/min), malate dehydrogenase (MDH) and phosphorylase (PH), in biopsied muscle. No differences were evident between Groups A and B for % slow twitch (ST) and % fast twitch (FT) fibers, or in area FT or ST. Nor was there any difference in the mean activities of succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) between the groups. Significant correlations were found between VO2 max and SDH, VO2 max and MDH, and between SDH and MDH. These data also indicate that an extremely high percentage of FT or ST fibers may not be a requirement for success in competitive cycling as has been found in earlier studies on sprint or endurance running.

Adolescent↗
PubMed1976

Muscle water and electrolytes following varied levels of dehydration in man.

In an effort to assess the effects of dehydration on the content of water and electrolytes (Na+, K+, Cl-, and Mg2+) in plasma and muscle tissue, eight men exercised in the heat (39.5 degrees C, 25%). Blood urine, and muscle biopsy samples were obtained before exercise and after the subjects had reduced their body weight by 2.2, 4.1, and 5.8%. On the average, plasma and muscle water (H2Om) contents were found to decline 2.4 and 1.2% for each percent decrease in body weight. Muscle sodium (Na+m) and chloride (Cl-m) content remained unchanged with dehydration, while muscle magnesium (Mg2+m) declined 12% as a result of the 5.8% dehydration. In terms of intracellular concentrations, K+i increased 7.2 and 10.6% at the 2.2 and 4.1% dehydration levels, respectively. Calculations of the resting membrane potential suggest that the water and electrolyte losses observed in these studies do not significantly alter the excitability of the muscle cell membrane.

Adult↗
PubMed1976

Skeletal muscle enzymes and fiber composition in male and female track athletes.

Muscle samples were obtained from the gastrocnemius of 17 female and 23 male track athletes, 10 untrained women, and 11 untrained men. Portions of the specimen were analyzed for total phosphorylase, lactic dehydrogenase (LDH), and succinate dehydrogenase (SDH) activities. Sections of the muscle were stained for myosin adenosine triphosphatase, NADH2 tetrazolium reductase, and alpha-glycerophosphate dehydrogenase. Maximal oxygen uptake (VO2max) was measured on a treadmill for 23 of the volunteers (6 female athletes, 11 male athletes, 10 untrained women, and 6 untrained men). These measurements confirm earlier reports which suggest that the athlete's preference for strength, speed, and/or endurance events is in part a matter of genetic endowment. Aside from differences in fiber composition and enzymes among middle-distance runners, the only distinction between the sexes was the larger fiber areas of the male athletes. SDH activity was found to correlate 0.79 with VO2max, while muscle LDH appeared to be a function of muscle fiber composition. While sprint- and endurance-trained athletes are characterized by distinct fiber compositions and enzyme activities, participants in strength events (e.g., shot-put) have relatively low muscle enzyme activities and a variety of fiber compositions.

Adenosine Triphosphatases↗
PubMed1976

Exercise induced sodium conservation: changes in plasma renin and aldosterone.

Previous studies have demonstrated a renal Na+ conservation during repeated days of exercise in the heat. The present study was intended to describe the role of plasma aldosterone (PAC) in reducing urine Na+ losses during and after 60 min of exercise (60% VO2max) in a warm environment (30 degrees C, 50-53% relative humidity). Additional measurements were made of plasma renin activity (PRA) in an effort to demonstrate the relationship between PRA and PAC. This study shows that a single bout of exercise can significantly reduce urine Na+, Cl-, and H20 excretions for up to 48 hours. Both PRA and PAC were significantly elevated during and immediately after exercise and returned to the pre-exercise level within 6-12 hours of recovery. Subsequently, ingestion of 180 mEq of Na+ each day with ad libitum water intake results in an increased NaCl storage and an expansion of the extracellular volume.

Adult↗
PubMed1976

Heat tolerance following diuretic induced dehydration.

In an effort to assess the effects of acute fluid loss on body temperature regulation during exercise, seven subjects (one female and six males) were studied on two occasions during two hours of cycling (35% Vo2max) in a hot environment (39 degrees C = DB, 35% = RH). One trial (D) was conducted following a 3% body weight reduction, achieved with 40-80 mg oral administration of a diuretic "lasix." A control exercise bout was performed with the subject normally hydrated (H). As a result of the diuresis, plasma volume (PV) decreased 15.3% (SE +/- 1.3), while heart rates during exercise increased 20-25 beats/min when compared to the H condition. Although significantly greater increases (P less than 0.05) in rectal and muscle temperatures occurred during exercise in the D trial, mean skin temperature (TS) was lower. Skin blood flow estimated from conductance values averaged 800 ml/min less during the D condition than during exercise in the H trial. Since the preliminary diuresis had no affect on sweat rate during exercise (D = 0.80 vs. H = 0.80 liters/hr), body heat dissipation appeared limited mainly by a reduction in peripheral blood flow. The diuretic induced dehydration was found to increase the sensitivity of some subjects to the exercise-heat stress, producing symptoms of heat exhaustion.

Adult↗