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Biomedical subjects

C Foster

Publications and source records attributed to C Foster.

At least 37 records · Page 2Linked to original sources
PubMed1987

Effect of age and training on aerobic capacity and body composition of master athletes.

Maximum oxygen uptake (VO2max) and body composition have been shown to deteriorate with age. How much of the decline is attributable to aging and how much is affected by reduced physical activity is not known. The purpose of this investigation was to determine the aerobic capacity and body composition of 24 master track athletes and to evaluate the relationship to age and maintenance of training over a 10-yr period. The subjects (50-82 yr of age) were retested after a 10.1-yr follow-up (T2). All continued their aerobic training, but only 11 were still highly competitive (COMP) and continued to train at the same intensity. The other 13 athletes studied became noncompetitive (post-COMP) and reduced their training intensity. The results showed the COMP group to maintain its VO2max and maximum O2 pulse while the post-COMP group showed a significant decline (54.2-53.3 vs. 52.5-45.9 ml X kg-1 X min-1; 20.7-20.8 vs. 22.4-20.0 ml/beat from test one (T1) to T2 for the COMP vs. post-COMP groups, respectively). Maximum heart rate declined 7 beats/min for both groups. Body composition showed no difference between groups from T1 to T2. For both groups body weight declined slightly (70.0-68.9 kg), percent fat increased significantly (13.1-15.1%), and fat-free weight decreased significantly (61.0-59.0 kg). Thus, when training was maintained, aerobic capacity remained unchanged over the follow-up period. Body composition changed for both groups and may have been related to aging and/or the type of training performed.

Aged↗
PubMed1986

Functional translation of exercise responses from graded exercise testing to exercise training.

This study attempts to develop a quantitative approach to the prescription of absolute exercise intensity during level ground ambulation (min/mile) or cycle ergometry (kpm) from responses observed during GXT. A total of 345 subjects performed GXT and exercise training sessions with either the Bruce treadmill protocol and level ground ambulation (N = 154) or cycle ergometry (N = 191). Responses from 90% of each group were used to generate equations for predicting training pace (or power output) from the time (or power output) during the GXT when target HR was achieved. FAI was also included in the prediction of training pace (or power output). The remaining 10% of subjects in each group were used to cross-validate the prediction equations. The correlation between the time (or power output) during GXT when the training HR was observed and the pace of ambulation (or power output) was 0.70 for treadmill walking and 0.88 for cycle-cycle. Correlations were increased by the addition of FAI to the prediction equation. The results of this investigation suggest that the absolute intensity of exercise for training can be predicted accurately from GXT results.

Cardiac Rehabilitation↗
PubMed1986

Tryptic digestion of myosin light chain kinase produces an inactive fragment that is activated on continued digestion.

Trypsin digestion of chicken gizzard myosin light chain kinase at limiting trypsin concentrations proceeds in stages. In the first stage, catalytic activity in the presence or absence of calcium and calmodulin decreases. In the second stage, activity in the absence of calcium increases, and the calcium-calmodulin complex no longer stimulates activity. The initial loss of activity is associated with the appearance of a 59,000-Da peptide that has been isolated and shown to have low catalytic activity. This peptide was further digested to a 55,000-Da peptide that has calcium-independent catalytic activity. This peptide has been isolated, and its affinities for the peptide substrate Kemptamide (Lys-Lys-Arg-Pro-Gln-Arg-Ala-Thr-Ser-Asn-Val-Phe-Ser-NH2) and ATP have been shown to be the same as those of the intact enzyme. Neither the 59,000-Da nor the 55,000-Da fragment binds calmodulin.

Calcium↗
PubMed1986

The NIH experience with precocious puberty: diagnostic subgroups and response to short-term luteinizing hormone releasing hormone analogue therapy.

Between 1979 and 1983, 129 children (95 girls) with precocious puberty were referred to the National Institutes of Health and received treatment for at least 6 months with the long-acting LHRH analogue D-Trp6-Pro9-NEt-LHRH. The majority (107 of 129) of the children had central precocious puberty mediated by activation of the hypothalamic-pituitary-gonadal axis in association with hypothalamic hamartomas (24 of 107) or other central nervous system lesions (21 of 107), or idiopathic precocious puberty (62 of 107). Hypothalamic hamartomas or other central nervous system lesions were a frequent cause of central precocious puberty in girls (27 of 87), but idiopathic precocious puberty was still the most frequent diagnosis (63%). Idiopathic precocious puberty was uncommon in boys (6%). The patients with peripheral precocious puberty included six girls with McCune-Albright syndrome and six boys with familial male precocious puberty. These children had peripheral sex steroid secretion in the absence of hypothalamic-pituitary-gonadal axis maturation. The children with combined peripheral and central precocious puberty included nine children with congenital adrenal hyperplasia and one girl with a virilizing adrenal tumor. In the patients with central precocious puberty or combined peripheral and central precocious puberty, LHRHa therapy caused suppression of gonadotropin and sex steroid levels (P less than 0.001), stabilization or regression of secondary sexual characteristics, and decreases in growth rate and in the rate of bone age maturation (P less than 0.005). Patients with peripheral precocious puberty, however, had no significant change in gonadotropin or sex steroid levels, growth rate, or the rate of bone age maturation, and no improvement in secondary sexual characteristics. Thus, LHRHa is an effective treatment of central precocious puberty and combined peripheral and central precocious puberty, but is ineffective in the therapy of peripheral precocious puberty.

Adrenal Hyperplasia, Congenital↗
PubMed1986

Exercise training following cardiovascular surgery.

The patient following cardiovascular surgery is a special, and probably somewhat easier, problem for the rehabilitation team than post-MI or angina patients. These patients may generally be viewed as somewhat more stable than post-MI patients. Rehabilitation thus focuses on minimization of bed rest, treatment of the sequale of sternotomy, and surveillance for new or changing medical problems. Physiological adaptations to training are likely to parallel those observed with post-MI patients, except that evidence of improved myocardial perfusion is less likely to be observed. Although GXT may be useful to evaluate progress in rehabilitation, it is unlikely to yield meaningful information regarding the adequacy of the surgical result. The possibility for exercise programs/risk factor modification as a vehicle for secondary prevention following CABGS is about as likely, and as well supported by the available literature, as it is following MI. Secondary prevention studies following other types of cardiovascular surgery are not available.

Angioplasty, Balloon↗
PubMed1986

Central circulatory adaptations to exercise training in health and disease.

Cross-sectional and longitudinal studies are reviewed that address the effects of training on several measures of central circulatory function, including gas exchange, cardiac output, left ventricular structure, and left ventricular function. Responses to training in healthy individuals, athletes, and patients with ischemic cardiovascular disease are compared.

Adult↗
PubMed1985

Reduced training intensities and loss of aerobic power, endurance, and cardiac growth.

Twelve subjects participated in an exercise program of cycling and running 40 min/day, 6 days/wk. After 10 wk, they continued to train with either a one-third or two-thirds reduction in work rates for an additional 15 wk. Frequency and duration for the additional training remained the same as during the 10 wk of training. The average increases in maximum O2 uptake (VO2 max) were between 11 and 20% when measured during cycling and treadmill running after 10 wk of training. VO2 max was not maintained at the 6-day/wk training levels with a one-third reduction in training intensity but was still higher than pretraining levels. With a two-thirds reduction in intensity, VO2 max declined to an even greater extent than with the one-third reduction. Short-term endurance (approximately 5 min) was maintained in the one-third reduced group but was markedly reduced in the two-thirds reduced group. Long-term endurance was decreased significantly from training by 21% in the one-third reduced group (184-145 min) and by 30% in the two-thirds reduced group (202-141 min). Calculated left ventricular mass, obtained from echocardiographic measurements, increased approximately 15% after training but returned to control levels after reduced training in both groups. These results demonstrate that training intensity is an essential requirement for maintaining the increased aerobic power and cardiac enlargement with reduced training.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1985

Screening for developmental disabilities.

Developmental disabilities are responsible for a combination of severe physical, mental, psychological and social deficits. They develop before age 22 years and involve a little more than 1% of the population. Screening for developmental disabilities is the first step in their prevention. Various screening instruments are available for use throughout the developmental years that are designed to detect the wide variety of developmental problems that interfere with a developing person's optimal adaptation to his or her environment. The screening instruments must be inexpensive, reproducible, widely available and cost effective to the child, family and society.

Adult↗
PubMed1979

Training adaptations in skeletal muscle of juvenile diabetics.

Skeletal muscles from 12 male, juvenile-onset diabetics (JD) and 13 nondiabetics (ND) were studied to determine the effects of endurance training on mitochondrial enzyme activities, lipoprotein lipase (LPL) activity, and the oxidation of lipids (14C-palmityl CoA) in vitro. Ten weeks of endurance running (30 min/day, 5 days/wk) resulted in 11.0 and 12.9% gains in aerobic capacity for the JD and ND groups (P greater than 0.05), respectively. Both groups showed significant (P less than 0.05) increases in muscle LPL, carnitine palmityl transferase, succinate dehydrogenase, and hexokinase activities with training. Though the pretraining capacities for 14C-palmityl CoA oxidation were similar for both ND and JD groups, the diabetics showed a 41% greater improvement in the measurement of muscle lipid oxidation after training than did the ND group. The principal finding of this research was that skeletal muscle of juvenile diabetics who are in moderate insulin balance shows adaptations to endurance training that are similar to those of nondiabetic men.

Adult↗
PubMed1979

Effects of preexercise feedings on endurance performance.

Eight male and female students were studied during exercise to exhaustion on a bicycle ergometer at 80 and 100% of Vo2max following the ingestion of water (W), 75 g of glucose (G) or a liquid meal (M) (10 g protein, 12.5 g fat, 15 g CHO). When compared to the endurance ride (80% Vo2max) in the W treatment, endurance performance time was reduced by 19%, (p less than .05) (53.2 to 43.2 min) as a result of the preexercise glucose feeding (Trial G). No difference in performance at 80% Vo2max was found between the W and M trials. The preexercise feedings had no effect on exercise time to exhaustion at 100% Vo2max. During the G and M trials at 80% Vo2max, most of the subjects demonstrated a transient decline in serum glucose (less than 3.5 mM). After 30-40 min. of exercise, however, serum glucose returned to normal and was seldom low at the time of exhaustion. Serum free fatty acids (FFA) were depressed throughout the G trial. The results of these experiments indicate impaired lipid mobilization following CHO ingestion. The present data support our earlier findings (11) which demonstrate that glucose feedings 30-45 minutes before endurance exercise increase the rate of CHO oxidation and impede the mobilization of FFA, thereby reducing exercise time to exhaustion.

Adult↗
PubMed1978

Skeletal muscle enzyme activity, fiber composition and VO2 max in relation to distance running performance.

Muscle biopsy samples were obtained from the gastrocnemius of 26 well-trained runners of widely varying ability. Portions of the sample were analyzed for succinate dehydrogenase (SDH) activity and for muscle fiber composition. VO2 max was determined during uphill treadmill running. Mean values for muscle SDH activity (14.6 U/g), fiber composition (55% slow twitch) and VO2 max (60.9 ml/kg x min(-1)) were lower than reported previously for groups of elite and sub-elite runners. The physiological data were consistent with the performance ability of the sample [5 : 12,11 : 20 and 36 : 40 (min :s) for 1, 2 and 6 miles, respectively]. Within the sample, performance was most strongly related to VO2 max (r=-0.84,-0.87 and -0.88 for 1, 2, and 6 miles). There was little relationship between muscle SDH activity and either performance (r=-0.11, -0.14, -0.20 for 1,2, and 6 miles) or VO2 max (r=0.23). The relationship between muscle fiber composition and performance was only modestly strong (r=-0.52,-0.54, -0.55 for 1,2, and 6 miles). The results indicate that the primary determinant of cross-sectional differences in running performance is VO2 max. Skeletal muscle metabolism apparently contributes little to these cross-sectional differences and may be of much greater importance to variations in performance within an individual.

Humans↗
PubMed1978

Sequence of return of neurological function and criteria for safe ambulation following subarachnoid block (spinal anaesthetic).

Twenty-three adult men were studied during and after subarachnoid block anaesthesia for elective surgery. Measurements were obtained of mean arterial pressure and pulse, both supine and after standing for five minutes, core body (tympanic) and peripheral skin (toe) temperatures and blood flow in the leg. Time of measurements included one hour after the injection of tetracaine and after regression of the block. Results obtained indicate that the sequence of return of neurological activity following tetracaine subarachnoid block is sympathetic nervous system activity, pinprick sensation, somatic motor function followed by proprioception in the feet. This progression provides the basis for recommended criteria which indicate when it is safe for patients who have been subarachnoid block anaesthesia to become ambulatory. These criteria include: (1) return of pinprick sensation in the peri-anal area (sacral 4--5); (2) plantar flexion of the foot (while supine) at pre-anaesthetic levels of strength; and (3) return of proprioception in the big toe, always provided that the patient is not hypovolaemic or sedated.

Adult↗
PubMed1978

Prevention of post-anaesthesia shivering.

This study involves ventilation of the lungs with warmed humidifed anaesthetic gases during prolonged elective abdominal operations. Tympanic, oesophageal and toe temperatures were compared bewteen twenty warmed and twenty un-warmed patients at various times during operation and recovery. Fifty per cent (10/20) unwarmed patients shivered in the recovery room, while none of the warmed patients shivered. Our data indicate that pulmonary ventilation with warm humidified anaesthetic gases provides heat transfer by the lungs, preventing hypothermia during operation and post -anaesthesia shivering is prevented by maintaining the patient normothermic in both the operating room and the recovery room.

Anesthesia, General↗