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Biomedical subjects

W L Haskell

Publications and source records attributed to W L Haskell.

At least 163 records · Page 9Linked to original sources
PubMed1981

Genetic analysis of the Stanford LRC family study data. II. Structured exploratory data analysis of lipids and lipoproteins.

A newly developed methodology for the assessment of mode of inheritance of continuously distributed traits in nuclear families, structured exploratory data analysis (SEDA), is applied to lipid and lipoprotein measurements. Specifically, three measures: the major gene index (MGI), the pairwise midparental correlation coefficient (MPCC), and the offspring between parents (OBP) curves are used to determine whether these trait expressions are more major gene, sporadic, or multifactorial relative to one another. Triglycerides and the closely-related VLDL-cholesterol measurement appears to be transmitted through some major components. HDL-cholesterol measurements are more consistent with some degree of multifactorial transmission or a major gene model with additive allelic effects and similar allele frequencies. The results for LDL-cholesterol suggest a modicum of major gene influences. The composite total cholesterol measurement appears to be under multifactorial transmission but of lower order than height. Younger families who were selected through a parent with high lipid levels exhibit some major gene influences which do not appear in the older families. Several possible explanations are proposed for this difference.

Cholesterol↗
PubMed1981

A comparison of the Sphygmetrics SR-2 Automatic Blood Pressure Recorder to the mercury sphygmomanometer in population studies.

The Sphygmetrics SR-2 Automatic Blood Pressure Recorder uses an infrasonic technique for detecting artery wall motion to estimate systemic arterial pressure and produces a permanent record of the results. It therefore is potentially useful in reducing observer bias in epidemiologic studies of blood pressure (BP). Two blood pressures were recorded in 21 men and 50 women using the SR-2 simultaneously with two auscultators using a biaural stethoscope and mercury syhgmomanometer. The SR-2 measured slightly higher systolic nd slightly lower diastolic pressures on average, but the differences were not significant. The two auscultators were highly correlated with one another (r = 0.99 systolic/0.97 diastolic) and with the SR-2 (0.93 and 0.92 for systolic, 0.84 and 0.85 for diastolic). The correlations were unrelated to sex, age, or antihypertensive medication status, but the correlations between th SR-2 and either auscultator for diastolic BP were quite low (0.36, 0.55) in subjects whose relative weight was below 1.0. Interpretation of the SR-2 disc was very reliable, with inter- and intra-reader correlations being 0.99 for systolic and 0.84 to 0.94 for diastolic. The SR-2 was found to be comparable to auscultation in estimating systolic BP in a heterogeneous population which has the advantages of reducing observer bias and producing a permanent record. Its use in estimating diastolic pressure in thin individuals and children needs further evaluation.

Adult↗
PubMed1981

Cardiovascular responses to handgrip isometric exercise in patients following cardiac transplantation.

The effects of cardiac denervation on the hemodynamic responses to isometric handgrip contraction were studied in patients 1--5 years after allograft cardiac transplantation. The objective of these studies was to determine the role of cardioacceleration and myocardial contractility on the increase in systemic arterial pressure during isometric exercise. Initially, noninvasive measurement of brachial artery pressure and heart rate during 60 seconds of isometric exercise at 50% of maximal voluntary contraction (50% MVC) were recorded in 23 cardiac transplant patients, 18 ischemic heart disease patients, and 15 healthy controls. While the increases in arterial pressure were not significantly different among the three groups and the heart rate response for the healthy controls and ischemic heart disease patients were similar, the transplant patient's heart rate remained essentially unchanged. In an attempt to determine the mechanisms for the increase in arterial pressure, despite any increase in heart rate in transplant patients, we recorded left ventricular volumes before and at the end of 50% MVC using fluoroscopy of tantalum midwall myocardial markers in seven cardiac transplant recipients and seven nontransplant cardiac surgery patients. The rise in arterial pressure during isometric exercise in both groups of patients resulted from a significant increase in peripheral vascular resistance but not in stroke volume or cardiac output. These data demonstrate that the rise in arterial pressure observed during isometric exercise can be achieved by increased peripheral vascular resistance alone in patients who lack the capacity to increase heart rate or stroke volume.

Adolescent↗
PubMed1981

Carotid palpation, coronary heart disease and exercise rehabilitation.

Heart rate, determined by palpation of the carotid, radial, or temporal artery, is commonly used to monitor exercise intensity. It is known that massage of the carotid artery has a baroreceptor reflex effect on the heart rate. The heart rate, monitored with and without carotid palpation, at rest, during exercise, and immediately post-exercise was determined in 60 male cardiac patients (39-65 years of age) following either myocardial infarction (n=52), bypass surgery (n=6), or those with angina pectoris (n=2). The mean changes in heart rate with carotid palpation in the testing group were -3.5 bpm at rest and -2.2 bpm during exercise; in the training group the changes were +0.8 bpm at rest -3.1 bpm post exercise. While the mean decrease at rest in the testing group was statistically significant, each of the decreases in resting, during, and post-exercise heart rates were too small to be accurately monitored by palpation over a 10- or 15-sec count, a usual procedure in exercise rehabilitation programs. Provided the patients are correctly instructed and technique regularly checked, there appears to be no reason why carotid palpation should not be used in cardiac exercise rehabilitation programs to determine resting, exercise, or post-exercise heart rates.

Adult↗
PubMed1981

Comparison of nutrient intake in middle-aged men and women runners and controls.

Runners and other active individuals typically have plasma lipoprotein patterns different than their more sedentary peers. In an attempt to determine if these patterns could be explained by dietary differences, we studied nutrient intake in middle-aged (35-59 yr) men and women runners averaging 55-65 km/wk, and inactive controls. The runners were leaner (P less than or equal to 0.0001) and had higher caloric intakes (40-60% higher on a weight-adjusted basis); they also ate more fat and carbohydrate (P less than or equal to 0.01), and were more likely to consume alcoholic beverages. When nutrient intake was expressed as a percent of total calories, the runners ate less protein (P less than or equal to 0.001). The runners obtained a smaller percentage of calories from starch and a greater percentage from other carbohydrates. Differences in nutrient intake seemed unlikely to account for observed differences in plasma lipids and lipoproteins between the runners and controls.

Adult↗
PubMed1980

HDL-cholesterol and other plasma lipid and lipoprotein concentrations in middle-aged male and female tennis players.

Fasting plasma lipid and lipoprotein concentrations were determined in 25 men and 25 women (mean ages 42 and 39 yr respectively) whose exclusive mode of regular exercise was tennis play. When compared to a sedentary group matched for age, sex, and education, the tennis players exhibited similar plasma total cholesterol and LDL-cholesterol concentrations and significantly lower triglyceride and VLDL-cholesterol concentrations. Plasma HDL-cholesterol was significantly higher in the tennis players (57.8 +/- 13.9 versus 46.2 +/- 12.0 mg/100 ml in the men and 73.9 +/- 12.3 versus 61.7 +/- 13.3 mg/100 ml in the women). When we simultaneously controlled for age, relative weight, cigarette smoking, alcohol intake, and oral contraceptive use (in females), the significance of the difference in plasma HDL-cholesterol as well as triglyceride and VLDL-cholesterol concentrations was unaffected in the males but substantially reduced in the females. It is concluded that frequent tennis playing is associated with increased plasma HDL-cholesterol concentrations and that this relationship is independent of other factors known to alter plasma HDL-cholesterol concentration.

Adult↗
PubMed1980

Left ventricular response to isometric exercise in patients with denervated and innervated hearts.

Patients with cardiac denervation resulting from allograft transplantation have been observed to increase their diastolic and systolic blood pressure during isometric exercise without concomitant cardioacceleration. To determine the mechanism for the blood pressure increase, heart rate, blood pressure, and ventricular volumes (measured using fluoroscopy of tantalum midwall myocardial markers) were recorded before and after a 50% maximal voluntary contraction. Seven cardiac transplant recipients (denervated heart) and seven nontransplant patients (innervated heart) were studied. Innervated and denervated heart patients increased systolic blood pressure by 16% and 21% and total peripheral resistance by 20% and 12%, respectively. The percentage responses were not significantly different between groups, except for heart rate, which increased 17% in innervated heart patients and 2% in denervated heart patients (p less than 0.05). Neither group had enhanced contractility or increases in cardiac output, suggesting that the blood pressure increases resulted in both groups from increased peripheral resistance.

Adult↗
PubMed1980

Cardiorespiratory responses of cardiac transplant patients to graded, symptom-limited exercise.

The electrocardiographic and ventilatory responses of 15 denervated heart patients who had undergone cardiac transplantation and 14 age-matched, normally innervated men were compared to assess the pattern of response to graded treadmill exercise. A 5-minute postexercise venous lactate sample was also obtained. Respiratory exchange ratio and ventilation (Ve) were higher in denervated patients than in normals during submaximal exercise. Peak values (normals vs denervated) for heart rate (172 vs 159 beats/min), blood pressure (189 vs 167 mm Hg), oxygen uptake (37 vs 25 ml/kg/min), oxygen pulse (0.22 vs 0.16 ml/kg/beat) and work time (26.2 vs 18.0 minutes) were higher in normals than in cardiac transplant recipients. Peak ventilatory equivalent (2.14 vs 3.13 l/ml/kg) and lactate values were higher for transplants than for normal subjects, but there were no significant intergroup differences in peak Ve or in the respiratory exchange ratio. In cardiac transplant recipients, work time correlated inversely with a measure of rejection history (r = -0.59, p less than 0.01). The response of cardiac transplant recipients to treadmill work differs from that of normal men and reflects a diminished ability to meet the oxygen demands of the exercising periphery.

Adult↗
PubMed1980

Physiological profile of middle-aged male and female tennis players.

Cardiorespiratory characteristics, relative body fat, grip strength and selected skinfolds, circumferences and bone diameters were determined in 25 males and 25 females (31--55 yr) whose exclusive mode of regular exercise was tennis (9.7--11.1 hr/wk). Mean resting heart rates were 54 beats/min for the males and 61 beats/min for the females. Mean resting blood pressures were 117/75 and 107/68 mmHg for the males and females, respectively. Compared to normally active populations of the same age and sex, the tennis players displayed an above average maximal oxygen uptake (mean values equal 50.2 ml/kg.min-1 for the males and 44.2 ml/kg.min-1 for the females), below average relative body fat (mean values equal 19.3% and 20.3% for the males and females, respectively), greater dominant grip strengths, and similar non-dominant grip strengths. The results indicate that either physically superior individuals choose to play tennis, or that regular tennis participation produces above average levels of fitness, or both.

Adipose Tissue↗
PubMed1980

Strenuous physical activity, treadmill exercise test performance and plasma high-density lipoprotein cholesterol. The Lipid Research Clinics Program Prevalence Study.

During the Lipid Research Clinics North American Prevalence Study, plasma lipoprotien determinations and treadmill exercise testing were performed on 2319 white men and 2067 white women ages 20 years or older randomly selected from population surveys by nine clinics in the U.S. and Canada. Before exercise testing, participants were asked if they performed any strenuous physical activity on a regular basis. Data were analyzed to determine the relationship of plasma high-density lipoprotein (HDL) cholesterol to treadmill exercise test performance and a self-report of strenuous activity. Neither treadmill exercise test duration nor heart rate response to submaximal exercise was significantly related to HDL cholesterol levels for either men or women. However, participants who reported some strenuous physical activity generally had higher HDL cholesterol levels than those who reported none, and the more active men ages 30-49 years and active women ages 20-39 had significantly higher values (p < 0.05). When HDL cholesterol was adjusted for age, body mass index, alcohol use, cigarette smoking and interclinic population variation, more active men (47.1 vs 45.2 mg/dl; p = 0.0001) and more active women (59.6 vs 57.7 mg/dl; p = 0.02) had higher HDL cholesterol levels than their sedentary counterparts. Thus, the association between HDL cholesterol and reported physical activity was, at least in part, independent of other factors that influence HDL cholesterol concentration, but was not associated with exercise tolerance as determined by treadmill exercise testing.

Adult↗
PubMed1979

Death during jogging or running. A study of 18 cases.

We investigated the circumstances of death and the medical and activity histories of 18 individuals who died during or immediately after jogging. Thirteen men died of coronary heart disease (CHD) and four men and one woman died of other causes. Six CHD subjects had medical histories relevant to the cardiovascular system, but only one had diagnosed CHD. Six CHD subjects experienced prodromal symptoms but continued vigorous exercise programs. Two subjects had exercised less than a month, but most had trained regularly for years. The CHD risk factors for the CHD cases did not differ significantly from those for other age-matched, physically active men. Superior physical fitness does not guarantee protection against exercise deaths. Physicians and exercising adults should be aware of this fact and give appropriate attention to possible prodromal symptoms.

Adult↗
PubMed1979

The effect of exercise on plasma high density lipoproteins.

The influence of vigorous activity in man on plasma lipids and lipoproteins is reviewed, with particular emphasis on high density lipoproteins. Both cross sectional and longitudinal (or training) studies have been reported, many of them of less than ideal design. Nonetheless, a consistent pattern emerges in which increased exercise levels lead to lower plasma concentrations of triglycerides and very low density lipoproteins, and of low density lipoproteins. High density lipoprotein levels increase. Sometimes, but not uniformly, plasma total cholesterol level falls as the result of these changes. The increase in plasma high density lipoprotein appears to be the result largely of an increase in the less dense HDL2 subfraction. Plasma apolipoprotein A-I levels (but not apo-A-II levels) seem to increase concomitantly. The precise biochemical mechanism responsible for these changes has not been elucidated; but the recent finding of increased lipoprotein lipase activity in adipose tissue and muscle of endurance runners suggests that increased lipolytic rate of triglyceride-rich lipoproteins may be an initial step in a sequence of events leading to higher plasma levels of HDL-2.

Aging↗
PubMed1979

Evaluation of the echocardiogram as an epidemiologic tool in an asymptomatic population.

An asymptomatic adult population of 196 men and women was studied with the echocardiogram to derive age- and sex-specific "normal" values for a number of clinically used echocardiograhic variables. The results are in general agreement with previously published normal values. Body position during the examination, age and sex influence the echocardiographic results; body surface area correction normalized most of these effects. The prevalence of occult abnormalities determined by the echocardiogram is 7%; the most common finding was mitral valve prolapse. Inter- and intraobserver variability was assessed. The interobserver differences found on analysis are statistically, but not clinically , significant. The echocardiogram appears to be a suitable tool to use in epidemiologic studies to detect selected cardiac abnormalities, but is limited for this purpose because some subjects in such a population cannot be adequately examined.

Adult↗
PubMed1979

Cardiovascular responses to repeated treadmill exercise testing soon after myocardial infarction.

To determine the response to repeated treadmill exercise testing soon after uncomplicated myocardial infarction, 24 males (mean age 54 +/- 6 years) performed two symptom-limited tests several days apart 3, 7 and 11 weeks after the acute event. Significant within-week differences were noted for peak exercise tolerance (mets) and peak heart rate at 7 weeks (p less than 0.05). Significant within-week differences in these variables were not noted for other weeks or for systolic blood pressure or heart rate-systolic blood pressure product for any of the three test periods. No significant within-week differences were noted for any variable recorded at a submaximal work load of 4 mets. The frequency of exercise-induced ischemic ST-segment depression, angina pectoris and premature ventricular complexes did not change from visit to visit and was highly reproducible (p less than 0.01). All test variables measured at peak exercise increased significantly between 3 and 11 weeks after infarction. We conclude that cardiovascular responses to symptom-limited exercise testing are highly reproducible in the 3 months after uncomplicated myocardial infarction. Changes in the response to treadmill exercise tests performed several weeks apart reflect alterations in cardiovascular performance.

Aged↗
PubMed1978

Cardiovascular complications during exercise training of cardiac patients.

The occurrence of major cardiovascular complications during exercise training of cardiac patients in 30 cardiac rehabilitation programs in North America was determined by questionnaire. These programs conducted medically supervised cardiac exercise classes in 103 locations and reported information on 13,570 participants who accumulated a total of 1,629,634 patient hours of supervised exercise. Cardiovascular complications were reported as nonfatal or fatal and included cardiac arrest, myocardial infarction and other. A total of 50 cardiac arrests were observed during exercise, 42 of which were successfully resuscitated while eight were fatal. Seven myocardial infarctions were reported; five were nonfatal and two were fatal. Four other fatalities were reported due to acute cardiopulmonary disorders. The average complication rate for all programs was one nonfatal and one fatal event every 34,673 and 116,402 patient hours of participation, respectively. Complication rates are lower in programs which continuously monitor the electrocardiogram during exercise and are lower when only the experience since 1970 is evaluated. These data support the recommendation that medically prescribed and supervised exercise can be performed reasonably safely by medically selected cardiac patients.

Coronary Disease↗
PubMed1977

Community education for cardiovascular health.

To determine whether community health education can reduce the risk of cardiovascular disease, a field experiment was conducted in three northern California towns. In two of these communities there were extensive mass-media campaigns over a 2-year period, and in one of these, face-to-face counselling was also provided for a small subset of high-risk people. The third community served as a control. People from each community were interviewed and examined before the campaigns began and one and two years afterwards to assess knowledge and behaviour related to cardiovascular disease (e.g., diet and smoking) and also to measure physiological indicators of risk (e.g., blood-pressure, relative weight, and plasma-cholesterol). In the control community the risk of cardiovascular disease increased over the two years but in the treatment communities there was a substantial and sustained decrease in risk. In the community in which there was some face-to-face counselling the initial improvement was greater and health education was more successful in reducing cigarette smoking, but at the end of the second year the decrease in risk was similar in both treatment communities. These results strongly suggest that mass-media education campaigns directed at entire communities may be very effective in reducing the risk of cardiovascular disease.

Adult↗
PubMed1977

Blood chemistry and lipid profiles of elite distance runners.

In summary, we conclude that the analysis of the blood profiles of elite runners offers no explanation for their superior fitness of physical ability when compared to the good runners. Selected enzymes related to cellular or tissue damage may be elevated in distance runners and could be classified as abnormal on routine clinical evaluation if unaware of their physical lifestyles. It is also important to note that certain blood profile parameters, especially the hematocrit, could be classified as abnormally low. Finally, the high degree of daily physical activity performed by the elite runners and good runners appears to be associated with a lipoprotein profile consistent with a low risk for development of coronary artery disease manifestations. These profiles persist despite increasing age in active running males.

Adult↗