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Biomedical subjects

C Foster

Publications and source records attributed to C Foster.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1984

Peak exercise and immediate postexercise imaging for the detection of left ventricular functional abnormalities in coronary artery disease.

Eleven patients without significant coronary artery disease (CAD) (group A), 22 patients with significant CAD and no prior myocardial infarction (MI) (group B), and 10 patients with CAD and a previous MI (group C) were imaged at rest, at peak exercise and immediately after exercise by first-pass radionuclide angiography. At peak exercise, mean left ventricular (LV) ejection fraction (EF) did not change significantly in group A or C and decreased significantly in group B. However, in all groups mean LVEF increased significantly immediately after exercise. Examination of potential criteria for an abnormal LVEF response showed that changes from rest to peak exercise were sensitive for detection of CAD but were not specific. Postexercise criteria were more specific but relatively insensitive: 15 of 32 patients (47%) with CAD showed a normal (greater than 5% increase over rest) response after exercise. Similarly, a regional abnormality at peak exercise was 100% sensitive, compared with a sensitivity of 78% after exercise for the whole group, and only 68% in patients without prior MI. Seven patients would have been misclassified as normal if postexercise imaging alone had been performed. The likelihood of an abnormal postexercise EF response was related to the extent of CAD: No patient with 1-vessel, 8 of 17 with 2-vessel and 9 of 12 with 3-vessel CAD showed such a response. Peak exercise imaging is necessary to achieve maximal sensitivity for the detection of CAD, and a high false-negative rate will be obtained if postexercise imaging only is used. The combination of peak exercise and postexercise imaging may be of value in assessing the severity of CAD.

Adult↗
PubMed1984

Work capacity and left ventricular function during rehabilitation after myocardial revascularization surgery.

A prospective randomized trial was conducted to evaluate the effects of exercise-based cardiac rehabilitation after myocardial revascularization surgery (MRS) on work capacity (measured in mets) and left ventricular function as determined from ejection fraction (LVEF). Twenty-eight patients undergoing MRS were randomly assigned to experimental (aerobic exercise, n = 19) or control (muscle relaxation and low-level exercise, n = 9) groups. Patients were studied before surgery (T1) and 2 (T2), 8 (T3), and 24 (T4) weeks after surgery with first-pass radionuclide angiography both while they were at rest and during maximal upright cycle ergometric exercise. Subsets of patients were also studied at T2, T3, and T4 at a standard workload of 75 W, and during maximal exercise 1 year after surgery (T5). Work capacity improved in both groups although significantly more so in the experimental group (3.9, 3.8, 6.0, and 7.3 mets and 3.7, 3.7, 4.9, and 5.7 mets at T1, T2, T3, and T4 in the experimental and control groups, respectively). The differences between groups were significant by T3. Peak exercise LVEF increased significantly in both groups from T1 to T2 then decreased at T3 and remained unchanged through T5. Peak exercise LVEF at T3 to T5 remained significantly above that observed at T1. LVEF responses were not related to the exercise program. During a standard workload, heart rate decreased, blood pressure increased, and LVEF did not change in either group. After conclusion of the formal protocol (T4), work capacity and LVEF did not change for either group throughout an additional 6 months (T5).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗
PubMed1984

The use of immunohistochemical probes in the study of benign and malignant breast disease.

A review is presented of the use of immunohistochemical probes in the study of the cellular pathology of the breast. Using a combination of monoclonal and polyclonal antisera it has been possible to investigate the relationship between myoepithelial cells and basement membrane components in benign breast disease and the disturbance of this relationship in early invasive and infiltrating ductal carcinomas. The use of immunohistochemical techniques at the ultrastructural level provides the methodology for future detailed analyses. The heterogeneous expression of antigenic determinants characteristic of epithelial cells in the normal breast is considered in conjunction with its relevance to the heterogeneity seen in the invasive tumours.

Animals↗
PubMed1983

Effect of exercise protocol on the left ventricular response to exercise.

The purpose of this study was to determine whether the left ventricular response during exercise radionuclide angiography would be influenced by exercise protocol. One hundred twenty healthy volunteers (aged 18 to 40 years) performed upright bicycle exercise using 1 of 5 protocols. Ejection fraction was measured using first-pass radionuclide angiography. Exercise protocols were as follows: (1) graded exercise (25 W increase every 2 minutes) to fatigue, heart rate greater than 85% of age-predicted maximum, n = 53; (2) graded exercise to 85% of age-predicted maximal heart rate or to fatigue with heart rate less than 85% of age-predicted maximum, n = 26; (3) graded exercise to fatigue, with "exercise" imaging performed immediately after exercise, n = 15; (4) abrupt presentation of a supermaximal work load (400 W), n = 10; (5) graded exercise to a work load of 75 W preceding the abrupt presentation of a supermaximal work load (300 to 400 W), n = 16. Protocols 2 and 3, representing less than maximal stress, yield higher ejection fractions than Protocol 1 and may reduce the sensitivity of exercise radionuclide angiography. Protocols 4 and 5, representing supermaximal stress, yield lower ejection fractions than Protocol 1 and may reduce the specificity of exercise radionuclide angiography. Thus, exercise protocol has a significant influence on the left ventricular response during exercise radionuclide angiography.

Adolescent↗
PubMed1983

Monoclonal antibodies as probes of human breast disorders.

A variety of monoclonal antibody probes to the human breast have been prepared by various groups of workers. These probes are revealing hitherto unrecognized biological and biochemical differences in both normal and neoplastic breast cells. Further study is needed, however, in order to understand fully the significance of these differences. In the meantime, the use of immune probes can improve our ability to detect disease at an earlier stage in sites such as the bone marrow, and may be heralding a new era in the detection and treatment of disseminated breast cancer.

Antibodies, Monoclonal↗
PubMed1983

Evaluation of functional capacity during exercise radionuclide angiography.

This study compared functional capacity during treadmill exercise testing and during bicycle exercise radionuclide angiography. 262 patients performed maximal upright bicycle exercise and also performed maximal graded exercise testing using either the Bruce (n = 158) or Naughton (n = 104) treadmill protocols. The functional capacity was well correlated between bicycle and treadmill for Bruce (r = 0.89), Naughton (r = 0.93), or combined treadmill (r = 0.90) protocols. However, the functional capacity was significantly lower during bicycle than during treadmill testing for Bruce (8.3 vs. 10.5 METs), Naughton (7.8 vs. 8.7 METs), or combined treadmill (8.1 vs. 9.8 METs) protocols. Treadmill functional capacity could be predicted from bicycle functional capacity using the following equations: Bruce METs = 1.00 X (bike METs) + 2.23, Naughton METs = 0.94 X (bike METs) + 1.40, and combined treadmill METs = 0.98 X (bike METs) + 1.85.

Adult↗
PubMed1983

Dysrhythmia detection in myocardial revascularization surgery patients.

Dysrhythmia detection in myocardial revascularization surgery patients. Med. Sci. Sports Exerc., Vol. 15, No. 4, pp. 281-286, 1983. In order to document the type and prevalence of significant dysrhythmias in myocardial revascularization surgery patients, cardiac electrical activity was recorded during graded exercise testing, 24-h ambulatory electrocardiography, and electrocardiographic-monitored exercise training. Patients participated in a cardiac rehabilitation program that began approximately 2 wk post-surgery, and attended three monitored exercise sessions per week for 12 consecutive weeks. Graded exercise testing and 24-h ambulatory electrocardiography were administered in the second and eighth weeks of the study (weeks 1 and 6 of the exercise program) post-surgery. Eighty-eight percent of the patients exhibited significant dysrhythmias. A greater number of significant dysrhythmias were found during the second 6 wk of the study in comparison with the first 6 wk. Graded exercise testing was not as effective as ambulatory electrocardiography and monitored exercise training in dysrhythmia detection. Not all dysrhythmias were detected by any one technique, thus a combination of methods may be best for optimal surveillance and detection.

Anti-Arrhythmia Agents↗
PubMed1983

Time course of lung volume changes during prolonged treadmill exercise.

It has been known since the 1920s that runners completing marathon races have reduced forced vital capacity (FVC) values. To investigate the time course of these lung volume alterations, we measured FVC and residual volume (RV) in 11 runners before, after, and at 30-min intervals during a 2.5-h treadmill run at just under their marathon pace (70% VO2max). Mean distance run was 21.5 +/- 1.5 (SD) miles in the 2.5-h period. During the first 60 min, both RV and total lung capacity (TLC) decreased by 110 ml, however, this change was not significant (P greater than 0.05). A high correlation (r = 0.93) was observed between delta RV and delta TLC during the first 5 min, while FVC remained unchanged. From 60-90 min, all lung volumes remained constant. From 90-150 min, lung volumes changed in a direction similar to that observed after a marathon, i.e., FVC decreased significantly (5.51 to 5.37 liter between 90 and 150 min, P less than 0.05), TLC remained unchanged (7.41 vs 7.42 liter, P greater than 0.05), and RV showed a nonsignificant increase from 1.90 to 2.05 liter (P greater than 0.05). The data are consistent with multiple mechanisms playing a role in pulmonary function changes during prolonged exercise. The smaller mean decrease in FVC observed in this study, as compared to that found during a marathon, suggested that the marathon imposes a greater demand on the lungs than did treadmill exercise of the duration and relative intensity used in this study.

Adult↗
PubMed1982

Comparative analysis of physiologic responses to three different maximal graded exercise test protocols in healthy women.

The purpose of this study was to compare the three most commonly used maximal graded exercise test (GXT) protocols in healthy women. Submaximal and maximal metabolic and hemodynamic responses were determined from two treadmill protocols, Bruce and Balke, and a bicycle protocol, in 49 women. Maximum oxygen uptake (VO2 max) was significantly different among protocols (Bruce=40.3, Balke=38.4, and Bike=36.6 ml/kg . min -1). Maximum heart rate (HR max) was significantly lower during Bike (178 beats/min) than during Bruce (182) and Balke (183) protocols. No differences in rate of increase in HR or systolic blood pressure (BP) per increase in multiples of the rest metabolic (METs) were found between Bruce and Balke protocols. The rate of recovery of HR and systolic BP was not different among tests. Comparisons of active and sedentary groups showed differences in VO2 max and submaximal HR and recovery HR at common minutes; however, the rate of increase in HR and systolic BP during exercise and the rate of decrease during recovery were not significantly different. Prediction of VO2 max with Bruce and Balke protocols from treadmill time was r=0.91 (SEE +/- 2.7 ml/kg . min -1) and r=0.94 (SEE 2.2 ml/kg . min -1), respectively. These data suggest a difference between men and women in increased HR and systolic BP per METs increase in exertion.

Adipose Tissue↗