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Biomedical subjects

D R Jacobs

Publications and source records attributed to D R Jacobs.

At least 235 records · Page 13Linked to original sources
PubMed1985

The effects of exercise and weight loss on plasma lipids in young obese men.

We studied the independent and combined effects of exercise training and weight loss on blood lipids under fixed diet and exercise conditions. Twenty-one obese sedentary men were randomly allocated to one of four treatment groups: (1) inactive and constant weight (control), (2) exercise training and constant weight, (3) inactive and weight loss, and (4) exercise training and weight loss. There were three study periods: a 3 week baseline period inactive and on an isocaloric diet, a 12 week treatment period, and a 3 week weight stabilization period. Exercise consisted of treadmill walking at an energy cost of 3500 kcal/wk for groups 2 and 4 with replacement caloric intake only in group 2. Group 3 reduced caloric intake by 3500 kcal/wk during the treatment period. Weight loss for groups 3 and 4 were 13.4 pounds and 13.7 pounds, respectively. Maximal oxygen uptake (mL/min) increased 6% in both exercise groups (2 and 4), and percent body fat decreased only in these groups. Regression analysis by group assignment on HDL cholesterol (HDL-C) showed that the inactivity-weight loss modality (group 3) and the exercise-constant weight modality (group 2) each significantly increased HDL-C, with an additive effect of exercise and weight loss (group 4). The rate of HDL-C change differed significantly between groups (P = 0.01). HDL-C increased 0.63, 0.61, and 1.89 mg/dL per 3 weeks or 2%, 2.4%, and 5.5% above baseline levels in groups 2, 3, and 4, respectively, while the control group decreased 0.11 mg/dL. Plasma triglycerides and very low-density lipoprotein (VLDL) cholesterol increased with exercise at constant weight (group 2) and decreased with exercise associated with weight loss (group 4). In conclusion, exercise and weight loss separately and independently increase HDL-C, and their effects are additive.

Adult↗
PubMed1985

Leisure time physical activity and its relationship to coronary risk factors in a population-based sample. The Minnesota Heart Survey.

Energy expenditure in leisure time physical activity was measured using the Minnesota Leisure Time Physical Activity Questionnaire in a probability sample of 25- to 74-year-old residents of the seven-county metropolitan area of Minneapolis-St. Paul, Minnesota. Geometric mean estimates of leisure time physical energy expenditure were 193 kcal per day for men and 111 kcal per day for women. Only 34% of men and 17% of women expended 2,000 kcal or more per week in leisure time physical activity. Energy expenditure, especially in heavy intensity activities, declined with age, more so for women than men. Significant associations were observed between leisure time physical activity, particularly heavy intensity activity, and other coronary heart disease risk factors. Greater heavy intensity activity was associated with higher education (r = 0.14 to 0.26), greater Type A behavior (r = 0.14 to 0.15), higher serum high density lipoprotein (HDL) cholesterol levels (r = 0.09 to 0.10), lower serum thiocyanate (r = 0.10 to -0.14), lower body mass index (r = -0.10 to -0.11), lower heart rate (r = -0.07 to -0.10), and lower systolic blood pressure (r = -0.06 to -0.09). Thus, although energy expenditure was generally low in this population, greater leisure time physical activity for the most part was associated with lower coronary risk factors.

Adult↗
PubMed1985

Comparison of nutrient calculation systems.

A set of 54 24-hour dietary recalls collected in 1975-1976 from males aged 35-57 years who were participating in a cardiovascular risk factor intervention program was submitted to three different nutrient calculation systems to investigate how much of a difference exists among systems in calculating nutrient intakes. The three computerized systems were of varying levels of sophistication. Among differences found, one system reported 1.4% more calories derived from polyunsaturated fat than the other two. For studies investigating the effects of dietary fat intake, this difference between systems may be important. Other significant group differences were seen for carbohydrate and alcohol. Although mean differences among the three systems were not great, dramatic differences were encountered when evaluating individual recalls. Nutrient intake data obtained from dietary recalls for individuals and for groups for whatever purpose are subject to the bias of the nutrient calculation system used. These biases should be considered when interpreting results, comparing results with other studies, and when developing treatment plans in the clinical setting. Recommendations for enhanced standardization include: 1) thorough descriptions in research reports of the particular system used; 2) exchange of standard menus between systems; 3) enhanced quality control of the coding process; 4) periodic updating of the nutrient data base to accommodate new food products and changes in composition of foods.

Adult↗
PubMed1985

The MRFIT behavior pattern study. II. Type A behavior and incidence of coronary heart disease.

Behavior pattern was assessed by interview for 3,110 men at eight centers in the Multiple Risk Factor Intervention Trial (1973-1976). The Type A pattern was not significantly associated with risk of first major coronary events (coronary death and definite nonfatal myocardial infarction) after a mean follow-up of 7.1 years. Crude relative risks for Types A1-A2 versus X-B were 1.08 in usual care, 0.82 in special intervention, and 0.92 overall. Adjustment for age, blood pressure, cigarette smoking, serum cholesterol, consumption of alcohol, and educational attainment yielded relative risks of 0.99 in usual care, 0.81 in special intervention, and 0.87 overall (95% confidence interval = 0.59-1.28). The Jenkins Activity Survey Type A score, obtained for 12,772 men at all 22 centers, was also not significantly associated with risk of first major coronary events. Overall, crude risks in the lowest (Type B) through highest (Type A) quintiles of the score's distribution were 5.0%, 4.4%, 4.0%, 4.3%, and 4.1%, respectively. The proportional hazards regression coefficient, adjusted for the variables listed above, was -0.006 (95% confidence interval = -0.015-0.003). These results raise questions regarding the robustness of the Type A hypothesis in its present form. Further studies are needed to investigate these questions and to evaluate the validity of procedures used to assess behavior patterns.

Adult↗
PubMed1985

Preparation, extraction and high performance liquid chromatography of cyclosporin A from plasma that contains interfering compounds.

Cyclosporin A (CyA) in human plasma-containing interfering compounds was determined by high performance liquid chromatography (HPLC) after the plasma had been subjected to incubation with proteinase K. This hydrolytic enzyme did not hydrolyse the cyclosporins and was therefore an ideal aid in eliminating interfering peptides selectively. The use of Extrelut as an extraction aid contributed much to higher yields of cyclosporins. Ethyl acetate, the extraction solvent used, gave less complex profiles on HPLC chromatograms than other solvents (eg diethyl ether and methanol) and contributed to a shorter chromatographic period per sample, an advantage in repetitive determinations.

Acetates↗
PubMed1984

Physical activity, smoking, and exercise-induced fatigue.

This study determined whether persons with coronary risk factors have increased fatigue during or after exercise. Ratings of perceived exertion were first shown to be a valid measure of fatigue; i.e., ratings of perceived exertion correlated with heart rate both during and after exercise and at each of three exercise tests (all within-subjects r greater than 0.88). Physical inactivity and smoking were associated with increased fatigue. Inactive men and smokers had higher levels of fatigue during both exercise and recovery conditions and at each of three exercise test. The increased fatigue of men who were inactive and smoked was not entirely due to their lower level of fitness. The risk factors of age, Type A behavior pattern, blood pressure, serum cholesterol, serum high-density lipoprotein, and obesity were not associated with increased fatigue. The increased fatigue experienced by inactive persons and smokers may account for their decreased compliance to exercise programs.

Adult↗
PubMed1984

Reliability of sampling during long-term ECG recordings in the detection of ventricular ectopy and abnormal ST segment depression.

Two ambulatory ECG recording-analysis methods were each compared in 10 subjects with a careful hand counted analysis of 16 continuously recorded hr and examined for total VEB count, complex VEB and ST-depression. The sampling method made a 28-sec tape recording every 15 min and was visually coded. The other method (conventional Holter) continuously recorded ECG data and used a dedicated computer with technician editing. Both recorders were simultaneously worn by study participants for 16 hr. Neither method showed a statistically significant difference from the hand counted data or systematic over- or under-estimation of clinically important ECG detections. A probability model is presented which provides a theoretical basis for the success of ECG sampling. Findings from this pilot study indicate electrocardiographic sampling may provide event detection comparable with the more conventional analyses, with considerably less data acquisition. The choice of ambulatory ECG recording mode should be governed by the level of quantification required, specific events to be detected and cost.

Arrhythmias, Cardiac↗
PubMed1984

Cardiovascular mortality trends in Minnesota, 1960-1978. The Minnesota Heart Survey.

Age-adjusted mortality rates from coronary heart disease (CHD) and other causes were examined in Minnesota for the years 1960-1978. Regions differed in CHD mortality levels and time trends. The greatest decline in CHD mortality occurred in the Twin Cities. The Northeast region had the highest CHD mortality. Influenza and pneumonia death rates were unrelated to CHD trends. Stroke mortality, which also declined sharply, showed no regional differences. Cancer mortality was highest in the Twin Cities and Northeast regions and increased significantly over the period; most of this increase was due to a striking increase in lung cancer mortality. The authors conclude that: (1) the CHD mortality decline in Minnesota was similar to that in the United States; (2) regional differences within the state in CHD mortality levels and trends were statistically significant; (3) CHD trends were not explained by influenza epidemics; (4) regions differed in mortality rates for hypertension in the same way as they did in CHD mortality, but differed little in stroke mortality. This leaves unclear the role of hypertension in regional CHD differences. (5) Trends in cancer mortality indicate that a general decline in mortality, due to factors affecting a wide variety of diseases does not explain the downward trends in CHD mortality.

Adult↗
PubMed1984

Longitudinal versus cross-sectional vital capacity changes and affecting factors.

Forced vital capacity (VC) and forced expiratory volume at 0.75 s (FEV) were measured in 592 Cretan island men aged 25 to 74 in 1960, 1965, and 1970. Vital capacity and FEV were directly correlated with height, but percentage changes were unrelated to height. A prominent accelerating decrease with age was also observed, the longitudinal decrement becoming more marked with advancing age. Chronic obstructive lung disease at entry significantly accelerated the loss of lung capacity, more so for emphysema than for chronic bronchitis. Among heavier men, body weight gains intensified the age-dependent loss of vital capacity and FEV. Borderline statistically significant differences in FEV decreases (adjusted for age, height and entry FEV) were seen between cigarette smoking groups. Heavy smokers had more diagnoses of chronic bronchitis and emphysema. Modifiable factors in minimizing the decrease of lung capacity with age include obesity, obstructive lung disease, and smoking, the last through development of chronic obstructive lung disease.

Adult↗
PubMed1984

Measured differences between fourth and fifth phase diastolic blood pressures in 4885 adults: implications for blood pressure surveys.

To examine in detail the relationship between fourth (D4) and fifth (D5) phase diastolic blood pressures, we used data from risk factor surveys of 4885 adults. Observers were carefully trained using audio tapes and double-stethoscope exams to record the onset of the first, fourth (muffling), and fifth (disappearance) phases of Korotkoff sounds with random-zero sphygmomanometers. The expected size of the difference between D4 and D5 pressures (D4-D5) was not discussed with observers. D4-D5 was greater (mean +/- SEM) in men (2.4 +/- 0.1 mmHg) than in women (1.9 +/- 0.1 mmHg), but two thirds of D4-D5s were not measurable, that is, 0 mmHg. Larger D4-D5s were associated with higher systolic and D4 levels, lower D5 levels, and younger ages. D4-D5 varied markedly among observers. Approximately 58% of D4-D5s exceeding 10 mmHg occurred among six observers who measured 16% of the blood pressures. However, generally the difference between D4 and D5 measured by our observers and methods was smaller than commonly believed. The possible reasons for this are discussed. We recommend that epidemiological studies measure and report both diastolic readings (D4 and D5) so that their interrelationship may be studied further in other populations.

Adult↗
PubMed1984

Spouse concordance of smoking patterns: the Minnesota Heart Survey.

Spouse concordance of smoking patterns and other lifestyle factors was examined in data provided by 560 married couples from the Minnesota Heart Survey. Married pair concordance was measured against a standard of concordance based on the frequencies in surrogate spouse pairs. Smoking patterns are found to be significantly concordant for married pairs. More married pairs than surrogate pairs tended to both smoke or both not smoke. Among smokers, married pairs are more similar than surrogate pairs in daily number of cigarettes smoked. Among ex-smokers, married pairs are more similar than surrogate pairs in the year they quit smoking. Younger couples with the least amount of education were most concordant and showed the greatest smoking rate. Five additional lifestyle factors showed an increased level of concordance for married over surrogate pairs. Concordance in these factors was not correlated with smoking concordance. It is suggested that married couples respond similarly to a shared environment made up of daily practices, social life, and leisure activities. Further, smoking intervention directed toward the married couple should be considered.

Adult↗
PubMed1984

Dietary measures of physical activity.

The relationships between cardiovascular fitness, body fatness, and the number of calories required to maintain stable body weight over a baseline period of three weeks were studied in 21 healthy obese males aged 20-44 years who participated in a controlled feeding experiment at the Division of Epidemiology (formerly the Laboratory of Physiological Hygiene) of the School of Public Health, University of Minnesota, in August 1980-June 1981. statistically significant relationships were found between the number of calories actually consumed per kg of body weight (kcal/kg) and body fatness (r = -0.79, p = 0.001), and number of calories consumer per kg of body weight and physical work capacity (VO2 max) (r = 0.76, p = 0.001). Using body fatness quartiles, the caloric intake per kg of body weight and VO2 max decreased progressively as body fatness increased through its four quartiles. These relationships were also seen when reported caloric intake from a three-day food record was used; however, the magnitude was attenuated. On the other hand, caloric intake unadjusted for body weight, whether actual or reported, was unrelated to both body fatness and VO2 max. To determine whether these relationships hold true for less obese subjects, the authors have also analyzed and compared their results with the data from previously reported feeding experiments done at the University of Minnesota. Correlations between body fat indices and actual caloric intake were similar for both studies. Therefore, the authors conclude that in these relatively young, healthy, and sedentary males with a wide range of body fatness and body weight, the observed relationships between caloric intake adjusted for body weight, body fatness and VO2 max reflect habitual physical activity. These data confirm epidemiologic observations of an inverse relationship between caloric intake per kg of body weight and body fatness, and provide a rationale for using caloric intake adjusted for body weight as a measure of long-term habitual physical activity. Thus, these data bolster the interpretation that an inverse relationship between caloric intake per kg of body weight and mortality reflects a positive health effect of long-term physical activity. This index may be particularly useful in large population studies.

Adult↗
PubMed1984

Prevalence of overweight and weight loss behavior in a metropolitan adult population: the Minnesota Heart Survey experience.

Data from two major surveys, conducted in the Minneapolis-St. Paul metropolitan area in 1973-74 and 1980-81, were used to estimate the prevalence of overweight. In 1980-81, weight history and the prevalence of dieting behaviors were also obtained. The prevalence of overweight was greater in the 1980-81 survey than in 1973-74. Increases were observed in all ages in women, but only in the 40-59 year age ranges in men. In 1980-81, dieting to control weight was widely reported by both sexes, even among those who had never been overweight. Of those who reported having been overweight, approximately one-third reported they had successfully reduced. More men than women reported having been overweight, but more women reported having dieted to lose weight. Formal weight reduction programs were used much more by women than men. Although most dieting attempts consisted of balanced, reduced calorie regimens, a significant percentage were "fad" types, whose nutritional safety may be questioned. Overall, contrary to findings based on clinical populations, weight reducing efforts often appear to be successful. Nevertheless, overweight remains a significant public health problem in this community.

Adult↗
PubMed1984

Coronary heart disease mortality trends in Minnesota, 1960-80: the Minnesota Heart Survey.

Age-adjusted mortality rates and trends from coronary heart disease (CHD) in Minnesota for the years 1960 to 1980 differed among eight health service areas. Regression of ten socioeconomic and demographic factors and intensive care and coronary care unit beds on area CHD mortality levels and slopes revealed a significant positive association only for levels of welfare income-maintenance assistance with CHD mortality levels; there were no associations with trends. Further studies are needed to explain variation within states of CHD mortality rate levels and trends.

Adult↗
PubMed1984

Citizen cardiopulmonary resuscitation training and use in a metropolitan area: the Minnesota Heart Survey.

To assess the prevalence and utility of citizen cardiopulmonary resuscitation (CPR) training, a systematic population-based sample of Minneapolis-St. Paul area adults, age 25-74 years, was interviewed in 1980-81. Twenty-three per cent were CPR trained. Of these, 13 percent have encountered out-of-hospital cardiac arrests and 38 per cent reported using their skills in such an emergency. Most of those performing out-of-hospital CPR (59 per cent) were health professionals. Only 19 per cent of trainees have maintained their certification by retraining within one year.

Adult↗
PubMed1984

Consumption of 'low-yield' cigarettes: its frequency and relationship to serum thiocyanate.

To determine the use and possible health risks of low-yield cigarettes, we ascertained the cigarette brands and serum thiocyanate (SCN) levels of 2,561 adult smokers (age 25-74) in population-based samples of seven upper Midwestern communities during 1980-82. Brands were coded according to December 1981 Federal Trade Commission (FTC) ratings for "tar", nicotine, and carbon monoxide (CO). Compared to 1980 data from the National Center for Health Statistics for the United States as a whole, a greater proportion of smokers in these communities smoked low-yield brands. More people with higher education than lesser and more women than men smoked low-yield cigarettes. Greater proportions of older people (65-75 years) than younger people (less than 65 years) smoked cigarettes in the highest and lowest brand yield categories. SCN, adjusted for number of cigarettes smoked and for sex, was only weakly associated with brand ratings for "tar" (r = +.12), nicotine (R = +.11), and CO (r = +.15). Furthermore, the gradient in SCN between lowest and highest quintiles of brand strength was less than 16 per cent--much lower than the 300-500 per cent gradient in smoke components implied by FTC ratings. These data add to the evidence that smoking low-yield cigarettes may not be significantly less hazardous than smoking high-yield brands.

Adult↗
PubMed1984

The inflammatory role of endotoxin in rabbit gram-negative bacterial endophthalmitis.

The authors used the limulus lysate assays to measure the amount of gram-negative endotoxin produced in two rabbits with experimentally induced gram-negative (Escherichia coli) endophthalmitis. A similar amount of purified enodotoxin was injected into the eyes of 14 rabbits to determine the rate of clearance of endotoxin from the rabbit eyes. Endotoxin was found in clinically inflammatory quantities 2 weeks after injection. Results of pathologic examination showed that endotoxin incites severe inflammatory responses in the eye, affecting the ciliary body, vitreous, choroid, retina, and optic nerve. These results suggest that the limulus lysate assay may be useful for detecting early gram-negative endophthalmitis, and that in such cases, early emergency vitrectomy may be needed to remove the inflammation-inciting endotoxin and preserve useful vision.

Animals↗