Biomedical subjects

G L Paul

Publications and source records attributed to G L Paul.

At least 19 recordsLinked to original sources

PubMed1991

Physiological responses to glycerol ingestion during exercise.

To study selected cardiovascular, thermoregulatory, and hormonal responses to the consumption of glycerol solutions during exercise, nine subjects cycled for 90 min at 50% peak O2 uptake in a 30 degree C, 45% relative humidity environment. Beverages tested included a 10% glycerol solution (G), a 6% carbohydrate-electrolyte beverage (CE), the 6% carbohydrate-electrolyte beverage plus 4% glycerol (CEG), and a water placebo (WP) ingested at regular intervals during the first 60 min of exercise. The beverages were administered in counterbalanced order with subjects serving as their own controls. Ingestion of the glycerol solutions resulted in an increase in plasma osmolality and attenuation of the decrease in plasma volume associated with the WP treatment (P less than 0.05). Plasma renin activity was highest with WP (P less than 0.05), and G was associated with increased antidiuretic hormone levels (P less than 0.05). Ratings of perceived thirst were lowest for CEG and G, and the frequency of gastrointestinal distress was greatest for G (P less than 0.05). However, no differences among beverage treatments were observed for heart rate, esophageal temperature, sweat rate, ratings of perceived exertion, or changes in cortisol and aldosterone levels. These data indicate that there are no substantial metabolic, hormonal, cardiovascular, or thermoregulatory advantages to the consumption of solutions containing 4 or 10% glycerol during exercise.

Adult↗

PubMed1991

Outcome studies.

Explore the source record for details and available documents.

Follow-Up Studies↗

PubMed1991

Fluid intake during an ultramarathon running race: relationship to plasma volume and serum sodium and potassium.

To assess the relationship between self-selected fluid intake patterns and changes in plasma volume and serum electrolytes during prolonged exercise, five men completed ultramarathon runs ranging from 50 to 100 km. There was a significant relationship between fluid intake and plasma volume changes but no changes occurred in either serum sodium or potassium. Subjects who ingested the most fluid during the race had a modest hemodilution without any changes in serum or potassium. This response may have been influenced by the consumption of beverages containing osmotically active solutes such as sodium and glucose.

Exercise↗

PubMed1991

Responses to varying rates of carbohydrate ingestion during exercise.

The purpose of this study was to determine how the ingestion of carbohydrate at varying rates influences physiological, sensory, and performance responses to prolonged exercise at 65-75% VO2max. Ten subjects ingested either a water placebo (WP) or carbohydrate solutions formulated to provide glucose at the rates of 26, 52, and 78 g, h-1 during 2 h of cycling exercise in a cool (10 degrees C) environment. Beverages were administered in a double-blind, counterbalanced design. A 4.8 km performance test followed each 2 h session. The average time required to complete the performance test was less with the carbohydrate feedings than with WP: mean (+/- SE) for WP = 505.0 +/- 18.7 s. 26 g.h(-1) = 476.0* +/- 8.8 s. 52 g.h(-1) = 483.8 +/- 12.7 s. 78 g.h(-1) = 474.3* +/- 19.1 s; *P less than 0.05 vs WP. Carbohydrate feeding resulted in higher plasma glucose and insulin, and lower free fatty acid concentrations than did WP. Changes in plasma osmolality, plasma volume, rectal temperature, lactate, heart rate, respiratory exchange ratio, ratings of perceived exertion, and sensory responses were similar among beverage treatments. Compared with WP, ingestion of the glucose beverages minimized changes in plasma ACTH and cortisol. In summary, carbohydrate feeding at the rates of 26 and 78 g.h(-1) was associated with improved exercise performance. The data further indicate that a dose-response relationship does not exist between the amount of carbohydrate consumed during exercise and exercise performance.

Adult↗

PubMed1989

Serum and urinary markers of skeletal muscle tissue damage after weight lifting exercise.

The purpose of this study was to determine whether high intensity weight lifting exercise produces elevations of urinary 3-methylhistidine (3-MH), serum creatine kinase activity (CK), and serum myoglobin concentration (MY), and whether trained weight lifters differed in such responses when compared to a group of untrained subjects. Ten experienced male weight lifters (EWL) and seven untrained male subjects (IWL) performed three sets of six weight lifting exercises at 70%-80% of 1 RM. All subjects consumed a meat-free diet. The 3-MH:creatinine (3-MH:CR) values decreased 24 h and 48 h following exercise (P less than 0.05). The 12-h and 24-h postexercise CK response and the 12-h postexercise MY response increased for both EWL and IWL (P less than 0.05). However, EWL had a lower 24-h postexercise CK response and lower 12-h and 24-h postexercise MY responses compared to IWL (P less than 0.05). Within 48 h following weight lifting exercise, skeletal muscle protein degradation (as assessed by 3-MH:CR values) decreased regardless of prior training experience whereas skeletal muscle tissue damage (as assessed by CK and MY responses) increased. However, prior weight lifting training appeared to diminish the extent of muscle tissue damage.

Adult↗

PubMed1989

Carbohydrate feeding and exercise: effect of beverage carbohydrate content.

The purpose of this study was to determine the effect of ingesting fluids of varying carbohydrate content upon sensory response, physiologic function, and exercise performance during 1.25 h of intermittent cycling in a warm environment (Tdb = 33.4 degrees C). Twelve subjects (7 male, 5 female) completed four separate exercise sessions; each session consisted of three 20 min bouts of cycling at 65% VO2max, with each bout followed by 5 min rest. A timed cycling task (1200 pedal revolutions) completed each exercise session. Immediately prior to the first 20 min cycling bout and during each rest period, subjects consumed 2.5 ml.kg BW-1 of water placebo (WP), or solutions of 6%, 8%, or 10% sucrose with electrolytes (20 mmol.l-1 Na+, 3.2 mmol.l-1 K+). Beverages were administered in double blind, counterbalanced order. Mean (+/- SE) times for the 1200 cycling task differed significantly: WP = 13.62 +/- 0.33 min, *6% = 13.03 +/- 0.24 min, 8% = 13.30 +/- 0.25 min, 10% = 13.57 +/- 0.22 min (* = different from WP and 10%, P less than 0.05). Compared to WP, ingestion of the CHO beverages resulted in higher plasma glucose and insulin concentrations, and higher RER values during the final 20 min of exercise (P less than 0.05). Markers of physiologic function and sensory perception changed similarly throughout exercise; no differences were observed among subjects in response to beverage treatments for changes in plasma concentrations of lactate, sodium, potassium, for changes in plasma volume, plasma osmolality, rectal temperature, heart rate, oxygen uptake, rating of perceived exertion, or for indices of gastrointestinal distress, perceived thirst, and overall beverage acceptance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Involuntary commitments to public mental institutions: issues involving the overrepresentation of blacks and assessment of relevant functioning.

This article contributes to the debate in the mental health and legal systems concerning involuntary commitments to mental hospitals. The focus is on issues involving the overrepresentation of Black people among adults committed to U.S. public mental institutions and issues involving the assessment of relevant behavioral functioning in particular. Empirical findings, legal principles and procedures, and methodological limitations are reviewed to identify problems in current practice and relevant evidence bearing on those problems. Special emphasis is placed on the possible explanations for the overrepresentation of Blacks and on dependable assessments of relevant functioning that are needed to justify the state's coercive power to involuntarily confine people, regardless of race. The article concludes with a summary and recommendations for research and practice.

Black or African American↗

PubMed1989

Urban psychiatric commitments: disability and dangerous behavior of black and white recent admissions.

Nationally black patients are overrepresented in public psychiatric institutions and are more likely than white patients to be committed involuntarily. This study of patients from 12 treatment units in the Chicago area, where these patterns were also true, compared the functioning of 227 acute admissions grouped by race (white or black) and admission status (voluntary or involuntary). Patients were assessed by highly trained independent observers using objective measures of dangerous behavior and disability levels, the relevant classes of functioning based on common principles underlying commitment statutes. No evidence was found that racial bias and discrimination in commitment and retention decisions would account for the overrepresentation of blacks among involuntary commitments to public institutions. Rather, the same factors that account for the overrepresentation of blacks compared with whites among all admissions may also explain their overrepresentation among the involuntarily confined. Changes in treatment programming and assessment practices are suggested.

Adolescent↗

PubMed1989

Dietary protein requirements of physically active individuals.

The dietary protein requirement of physically active individuals has received considerable scrutiny in recent years. Because the current United States Recommended Daily Allowance (USRDA) for protein (0.8 g/kg/day) already contains a safety margin (0.35 g/kg/day) to assure adequate protein intake, no increment in the USRDA was thought necessary to meet the demands of physical activity. Recently, collective evidence from research techniques utilising nitrogen balance, labelled amino acid isotopes, urea production and 3-methylhistidine excretion indicates that exercise (endurance and weightlifting) can significantly alter protein metabolism and that the dietary protein needs of physically active individuals may exceed the current USRDA. During endurance exercise, protein synthesis is depressed and protein degradation increases. Thus, amino acids become available for oxidation in energy-yielding processes. Amino acid catabolism has been estimated to contribute between 5 and 15% of the energy required during endurance exercise. Definitive conclusions regarding the changes that occur in protein synthesis and protein degradation during weightlifting exercise must await further research. The net contribution of amino acids to the energy required during weightlifting exercise is unknown but, due to the anaerobic nature of the event, it is most likely less than during endurance exercise. However, following both endurance and weightlifting exercise, protein synthesis increases. Based on current research, it is not yet possible to make recommendations for the daily protein needs of exercising individuals. It does appear that physically active individuals require more dietary protein per kilogram of bodyweight than sedentary individuals. However, when protein intake is expressed as a percentage of daily energy intake, physically active and sedentary individuals have similar requirements (approximately 12 to 15% of total energy as protein). Therefore, to cover the protein requirements of both physically active individuals and sedentary individuals it is suggested that future protein allowances be based on a percentage of the daily energy requirements. Protein consumption in excess of the current USRDA may minimise changes in body nitrogen stores, particularly during the first few weeks of training. However, further research is needed before a definitive conclusion can be made regarding protein ingestion and athletic performance.

Adult↗

PubMed1989

The effects of glucose, fructose, and sucrose ingestion during exercise.

The purpose of this study was to compare the physiological, sensory, and exercise performance responses to ingestion of 6% glucose, 6% fructose, and 6% sucrose solutions during cycling exercise. Twelve subjects completed three sessions consisting of 115 min of intermittent cycle ergometer exercise at 65-80% of VO2max followed by a timed performance bout requiring the completion of 600 pedal revolutions. During each of five 4-min rest periods, subjects consumed 3 ml.kg LBM-1 of one of the beverages. Beverages were presented in counterbalanced, double-blind fashion. Heart rate, VO2, plasma urate, plasma lactate, respiratory exchange ratio, and carbohydrate combustion rates changed similarly among beverage treatment. However, fructose was associated with lower plasma glucose and serum insulin, a larger loss of plasma volume, greater gastrointestinal distress and relative perceived exertion ratings, and higher plasma or serum concentrations of free fatty acids, fructose, and cortisol values than sucrose or glucose (P less than 0.05). Compared to sucrose and glucose, fructose feeding also resulted in lower lactate and HR values during the performance bout (P less than 0.05). Mean +/- SE cycling performance times were faster with sucrose and glucose than with fructose: 419.4 +/- 21.0 s, 423.9 +/- 21.2 s, and 488.3 +/- 21.1 s, respectively (P less than 0.05). Relative to 6% solutions of sucrose and glucose, ingestion of a 6% fructose beverage is associated with gastrointestinal distress, compromised physiological response, and reduced exercise capacity.

Adult↗

PubMed1988

Inconsistencies in paranoid functioning, premorbid adjustment, and chronicity: question of diagnostic criteria.

Despite the widely held belief that paranoid behavior is associated with good premorbid adjustment, low chronicity, and high current functioning in psychiatric inpatients, inconsistencies in the literature suggest that supportive evidence may be an artifact of the measurement model commonly used to index paranoid status. In a sample of 497 nonorganic inpatients selected from 19 treatment units, paranoid behavior, when measured by a dimensional/cumulative model, was not found to indicate higher functioning and associated relationships, but simply to reflect a narrower class of problem behavior. Only when paranoid status was defined using a traditional model based on the predominance of the defining class of behavior did paranoid subjects demonstrate better premorbid adjustment, lower chronicity, and higher levels of functioning than nonparanoid subjects. Serious problems exist in the use of information obtained from traditional predominance/class models for either theoretical or practical purposes.

Adolescent↗

PubMed1987

The effect of fluid and carbohydrate feedings during intermittent cycling exercise.

The purpose of this study was to determine the effect of ingesting water or carbohydrates solutions on physiologic function and performance during 1.6 h of intermittent cycling exercise in the heat (dry bulb temperature = 33 degrees C). Thirteen male subjects (24 to 35 yr) completed four separate rides. Each ride consisted of intermittent steady-state cycling (at 55 and 65% VO2max) interspersed with five rest periods. A timed 480 revolution cycling task completed each experimental session. During each rest period, subjects consumed 2 ml.kg-1 body weight of water placebo or solutions of 5% glucose polymer, 6% sucrose/glucose, or 7% glucose polymer/fructose. Beverages were administered in double-blind, counter-balanced order. No differences were observed among subjects in response to beverage treatments for changes in plasma concentrations of total proteins, sodium, potassium, lactate, or in osmolality, percent change in plasma volume, heart rate, oxygen uptake, respiratory exchange ratio, rating of perceived exertion, sweat rate, rectal temperature, or mean skin temperature. Compared to water placebo, the carbohydrate treatments produced higher plasma glucose values following 1 h cycling (P less than 0.01). Mean (SD) times for the 480 revolution cycling task: water placebo = 432 (43) s; glucose polymer = 401 (52) s; *sucrose/glucose = 384 (39) s; and *glucose polymer/fructose = 375 (30) s, where = P less than 0.001 compared to water placebo. Physiologic function was similarly maintained during exercise by all beverage treatments, while ingestion of sucrose/glucose and glucose polymer/fructose resulted in improved end-exercise cycling performance.

Adult↗

PubMed1986

Can pregnancy be a placebo effect?: Terminology, designs, and conclusions in the study of psychosocial and pharmacological treatments of behavior disorders.

This paper discusses several salient issues in the clinical research enterprise which were stimulated by chapters on research methods and placebo phenomena in White, Tursky and Schwartz (1985), Placebo: Theory, Research, and Mechanisms. These issues include the commonalities of questions, domains and classes of variables, and research strategies needed for the discovery, accumulation and application of knowledge regarding effective clinical treatments. Problems of unwarranted uniformity assumptions and absolute design requirements as well as the failure to attend to the conceptual relevance, strength and integrity of procedures are noted with examples from the systematic desensitization literature. Meta-analyses and indexes of effect size are also examined with examples demonstrating the need for especially cautious interpretation of these procedures. A re-emphasis of the construct validity approach with better designed and executed individual studies is endorsed as the best means to improve progress.

Adaptation, Psychological↗

PubMed1981

Staff performance: do attitudinal "effectiveness profiles" really assess it?

Performance differences were examined for mental hospital staff with divergent profiles on the Opinions About Mental Illness (OMI) that have been purported to reflect differential staff effectiveness. Two staff groups (N = 40 each) were selected, in pairs, from 19 treatment programs serving adult mental patients to provide extremes of "OMI-effective" vs. "OMI-ineffective" profiles while equating groups on demographic, experiential, and program characteristics that had previously been found to influence OMI scores or staff performance. Actual on-the-floor performance was assessed by direct hourly observations obtained on the Staff-Resident Interaction Chronograph over a full week in each program. The OMI effective group was found to perform greater amounts of overall activity and greater amounts of interaction with institutionalized residents than did the OMI-ineffective group. These differences in public job-relevant activity, likely, provide the basis for earlier reports of positive evaluations for staff who score in the OMI-effective direction. However, the groups did not differ in the specified nature and pattern of their staff-resident interactions when the overall rate of interactions was controlled. Such differences would be required for the OMI to be a measure of staff effectiveness in improving resident functioning. These results, in combination with previous studies, provide little support for the OMI as a measure of effectiveness or as an indirect measure of the goodness of staff performance. The OMI effective group did produce a higher frequency of interactions, and, thus, the OMI appears to serve as a useful descriptor of staff characteristics that might interact with other variables influencing effectiveness; but the absence of discrimination regarding the more crucial specific nature of interactions indicates that the OMI cannot substitute for direct assessment of actual staff performance.

Adult↗

PubMed1978