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Biomedical subjects

W D Block

Publications and source records attributed to W D Block.

At least 19 recordsLinked to original sources

Comparative effects of overweight on cardiovascular risk in younger versus older men.

The relation of age and body mass index (BMI) to atherosclerosis risk factors was examined in 357 men. Older (greater than or equal to 45 years) men had higher (p less than 0.01) systolic and diastolic blood pressures, fasting cholesterol and glucose, and 1-hour glucose and insulin levels. Fasting insulin and triglyceride levels were not significantly different between the 2 age groups. Although older men (n = 170) had greater values for several risk factors, overweight (BMI greater than 25.5 kg/m2) increased risk factors more in men younger than 45 years (n = 187). In younger men, those with higher BMIs had a greater prevalence, respectively, of blood pressure greater than 140/90 mm Hg (35.2 vs 11.2%, p less than 0.0001), cholesterol greater than 200 mg/dl (53.5 vs 29.3%, p less than 0.001), fasting triglycerides greater than 150 mg/dl (38.0 vs 10.3%, p less than 0.0001), 1-hour glucose greater than 160 mg/dl (15.5 vs 5.2%, p less than 0.05), fasting insulin greater than 11 microU/ml (28.2 vs 5.2%, p less than 0.0001), and 1-hour insulin greater than 110 microU/ml (28.2 vs 9.5%, p less than 0.001). In contrast, among older men, the prevalence of elevated blood pressure, cholesterol, triglycerides and glucose values was not significantly greater in the subgroup with high BMI. However, elevations of fasting (19.6 vs 6.4%, p less than 0.05) and 1-hour insulin (29.3 vs 11.5%, p less than 0.01) values were more common among older men with higher BMIs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Recognition of borderline carbohydrate-lipid metabolism disturbance: an incipient form of type IV hyperlipoproteinemia?

Blood glucose and insulin responses to oral glucose were measured in 33 men: 8 normal, 13 with borderline carbohydrate-lipid metabolism disturbance (BCLMD) (pre-beta-lipoproteinemia with normal cholesterol and triglyceride levels), and 12 with mild Type IV hyperlipoproteinemia. Average age was 30 years, and the percentage of ideal weight was 101%. Borderline patients exhibited hyperinsulinemia following oral glucose, notably at 30 min; they also demonstrated an apparent impairment in homeostatic control of blood glucose level, with a greater-than-normal decline in blood glucose in the 3- to 4-h period (by profile analysis). The Type IV patients, though of normal weight and adiposity, exhibited elevated late incremental insulin area (LIIA) (1-5 h) responses. Combining all data, fasting triglycerides correlated with LIIA (p = 0.0002); LIIA correlated with the percentage of adipose mass (p = 0.003), suggesting that LIIA reflects insulin resistance. Lipoprotein electrophoresis remains useful for detecting pre-beta-lipoproteinemia, which may occur even in persons with normal cholesterol and triglyceride levels. When present, it suggests the possibility of hyperinsulinemia following glucose ingestion, which in turn has been shown to be an independent predictor for the development of coronary heart disease. To gain increased understanding of the natural history of hypertriglyceridemia, persons with BCLMD should be studied separately from those with normal lipid and carbohydrate metabolism and from those with hypertriglyceridemia.

Adult

The influence of physical training on glucose tolerance, insulin sensitivity, and lipid and lipoprotein concentrations in middle-aged hypertriglyceridaemic, carbohydrate intolerant men.

The effects of 9 weeks of moderate intensity exercise training while on a weight-maintaining diet were studied in 19 untrained middle-aged, hypertriglyceridaemic, carbohydrate intolerant men. Initial mean maximum oxygen consumption was low (29.7 +/- 1.0 ml.min-1.kg-1; mean +/- SEM) and improved (34.2 +/- 1.4 ml.min-1.kg-1, p less than 0.01) with exercise training. Fasting glucose, insulin, lipid and lipoprotein concentrations did not change. While the abnormal glucose response to oral glucose did not change with training, insulin concentrations were significantly (p less than 0.05) lower at 90 and 120 min during the final oral glucose tolerance test. Insulin mediated glucose uptake did not change, indicating that the degree of exercise training failed to improve in vivo insulin sensitivity. Significant associations were found between the following parameters measured: fasting concentrations of triglycerides and insulin, very low density lipoprotein-triglycerides and glucose, and measures of in vivo insulin resistance and fasting insulin levels, suggesting that insulin resistance in these glucose intolerant subjects may play a role in their hypertriglyceridaemia. These data indicate that moderate increases in physical training alone are not sufficient to improve the carbohydrate, insulin and lipid metabolism of hypertriglyceridaemic, glucose intolerant men.

Basal Metabolism

Effect of exercise training on glucose tolerance, in vivo insulin sensitivity, lipid and lipoprotein concentrations in middle-aged men with mild hypertriglyceridemia.

The effects of 9 weeks of aerobic exercise training with maintenance of stable body weight upon insulin sensitivity and upon glucose, lipid, and lipoprotein concentrations were studied in 10 middle-aged men with mild hypertriglyceridemia. Following training, mean maximum oxygen consumption improved from 33.5 +/- 1.9 to 39.3 +/- 1.9 mL/kg/min (means +/- SEM), (P less than 0.01). Glucose concentrations, both fasting and during oral glucose tolerance testing, remained stable but both fasting insulin concentrations and insulin responses to oral glucose decreased (P less than 0.1 and less than 0.01, respectively). In vivo insulin sensitivity improved 25 +/- 6.1% (P less than 0.01) following training. Exercise training resulted in decreases in fasting serum triglyceride concentrations from 203 +/- 12.6 to 126 +/- 9.0 mg/dL (P less than 0.01), primarily as a result of the reduction in VLDL-triglycerides (P less than 0.01). The magnitude in percentage decrease of VLDL-triglycerides was found to be significantly correlated (r = 0.71, P less than 0.05) with the magnitude in percent increase in max VO2. Serum cholesterol levels declined from 211 +/- 8.9 to 193 +/- 11.9 mg/dL (P less than 0.01), and the ratio of HDL-cholesterol to total cholesterol was improved. This study demonstrates that exercise training at a level of intensity feasible for many middle-aged men has beneficial effects on several factors that have been associated with an increased risk of cardiovascular disease.

Adult

Effects of exercise training on plasma lipids and lipoproteins in rats.

We studied the effects of exercise training on plasma lipid and lipoprotein concentrations of rats on a high-fat and high-cholesterol diet. Twelve weeks of training occurred at moderate [Mod-Exer, 70% peak O2 consumption (VO2)] and high (High-Exer, 82% peak VO2) intensities. The duration of daily training sessions was adjusted to maintain equivalent energy expenditure between groups. Following training, body weight and lean body mass were 10% lower in the High-Exer group than the Mod-Exer or control groups. Compared with control values, carcass fat content was 33% lower for both trained groups. The oxidative capacity of skeletal muscle was approximately 30% greater in the trained groups compared with the control group. Total cholesterol, high density lipoprotein cholesterol, and total triglyceride concentrations in plasma were not different between the trained groups, but were 33-47% lower compared with the control group. The exercise-induced changes in plasma lipid and lipoprotein concentrations may be a result of a change in preferred substrate utilization in skeletal muscle toward a greater oxidation of lipid.

Animals

Relationship of oxygen uptake capacity, serum uric acid and glucose tolerance in males and females, age 10-69.

Age 10-69, 793 males and 80 females were tested on the treadmill as they walked at 4.83 km per hour (3.27 km per hour in subjects 60 years and older). Every three minutes, the grade was increased 3%. Maximal oxygen uptake (VO2max.) and related measurements were recorded during the third minute at each grade. Subjects age 10-39 exercised to exhaustion and VO2max. was measured. In subjects age 40-69, VO2max. was estimated from sub-maximal VO2 and heart rate. The sum of four skinfolds, serum uric acid (SUA) and one-hour glucose tolerance were also measured on these subjects. Body fatness was positively correlated with SUA and blood glucose and negatively correlated with VO2max. Age was negatively correlated with VO2max. and positively correlated with blood glucose. After removing the effects of age, weight and fatness, the correlation of VO2max. and SUA was low. Similarly, there was little or no correlation between VO2max. and blood glucose after the effects of age, weight and fatness were removed.

Adolescent

Comparative effects of physical training and diet in normalizing serum lipids in men with Type IV hyperlipoproteinemia.

The effect of milk physical training (PT) (group A), Type IV hyperlipoproteinemia (HLP) diet (group B), and PT plus Type IV HLP diet on serum lipids (group C) in 46 men with Type IV HLP was studied. Significant reductions in mean triglyceride (TG) levels from 163, 229, 196, to 136, 145, 116 mg/100 ml serum were found for groups A, B, and C, respectively. Following six weeks of intervention, cholesterol levels also dropped for all groups with the greatest reductions occurring in groups B and C. Minimal weight losses were found for all groups while groups A and C displayed significant reductions in body fatness, but both of these changes appeared independent of lipid reductions. It was concluded that either mild PT or HLP diet or both are effective means of lowering TG levels in Type IV HLP individuals. Furthermore, it appears that patients need to participate regularly in formal programs in order to maintain adherence to these interventions.

Adult

Habitual physical activity and glucose tolerance. Males age 16-64 in a total community.

The data being reported are part of an epidemiologic study of health and disease in an entire community, Tecumseh, Michigan. Approximately 1,300 males age 16-65 were classified into three groups on the basis of their habitual leisure and occupational physical activity. A blood sample was drawn one hour after a glucose challenge and analyzed for glucose concentration. A measure of body fatness (sun of four skinfolds) was also available on the men. Glucose concentration of the three physical activity groups was compared by analyses of variance within narrow age group. There was no significant relationship between glucose tolerance and habitual physical activity. There was a slight, but in some age groups significant, relationship between glucose tolerance and body fatness. The population was then divided within each age group into subgroups (thirds) by sum of skinfolds. The analysis was repeated in each age-fatness group. Glucose tolerance was better in the active men but only among the leanest subgroup of subjects.

Adipose Tissue

alpha1-Antitrypsin deficiency in clinic patients.

Five hundred patients undergoing complete medical examination, and 225 consecutive patients with abnormal pulmonary function tests were studied for alpha1-antitrypsin deficiency. Within the first group, respiratory disease was diagnosed significantly more often in patients with a variant Pi phenotype (MS, MZ, FF) than in the patients with the most common phenotype, MM. Furthermore, the frequency of heterozygosity (MS or MZ) was greater in the patients who had respiratory disease. When the first and second groups were compared, the prevalence of the variant phenotypes was not statistically different.

Female

Nutritional indexes of clients in a maternity and infant care project. I. The target population.

The Detroit Maternity and Infant Care Project (DMICP) is funded under Title V of the Social Security Act. Records of 198 pregnant women and their infants seen by a project nutritionist in fiscal 1971-72 were studied. The women were predominantly young (below twenty years of age), black, and not enrolled in school. Most were pregnant for the first time. About a third were overweight. Mean scores on the APGAR scale for the infants at birth were high (7 to 10). More than half of these young mothers brought their infants to the project center for check-ups six to ten times during the first year.

Adolescent

Nutritional indexes of clients in a maternity and infant care project. II. Dietary, anthropometric, and hematologic indexes of pregnant women and their infants.

Low intakes by 198 pregnant women of milk, fruit, and vegetables are reported: consumption of meat and bread and cereals was satisfactory. However, mean hemoglobin and hematocrit values were within acceptable ranges for these women, indicating that supplementation apparently compensated in part for poor dietary habits. Protein intake of the infants of these mothers was above recommendations, the advisability of which is questioned. Height and weight of the male and female infants at birth were above and below the 10th percentile, respectively. By the age of four months, however, all infants were equal to or above this level. Mean hemoglobin levels were above acceptable levels.

Adolescent

Nutritional indexes of clients in a maternity and infant care project. III. Relationships between developmental, medical, and nutritional variables.

Nutritional and medical records of the infants of 198 women of a low socioeconomic group were correlated with results of the Denver Developmental Screening Test. At one year, the infants' developmental age was above the norm. In addition, selected medical, nutritional, and developmental variables, as indicated by charts of the Detroit Maternity and Infant Care Project, were statistically analyzed for interrelationships. No correlation was found between hemoglobin levels, even though they were low for some infants, and developmental indexes. Prenatal weight gain of the mothers was statistically significant in relation to their infants' birth weight, height, and head circumference. Thus periodic monitoring of weight throughout pregnancy is recommended.

Child Development

Metabolic adaptation with physical training: 14C-acetate incorporation into tissue lipids.

Forty-eight rats were fed ad libitum, fasted 24 hr, rested 48 hr,and injected i.p. with 40 muCi of 14C-acetate/100 g body weight. Twenty-four rats had followed a progressive physical training program for 12 wk and 24 rats acted as their controls. Following this injection, the rats were sequentially sacrificed at 5-, 10-, 15-, and 20-min intervals and total cholesterol (TC), free cholesterol (FC), and triglyceride (TG) specific activity and concentrations were measured from serum, liver, triceps, and heart tissue. Curves relating specific activity to the time point data were fitted by the method of least squares. Comparison of these curves revealed that serum, liver, and triceps TC and FC specific activity were significantly higher in the trained rats. In contrast, corresponding TC and FC concentrations for these three tissues varied. Liver TC level was significantly less for the trained group, probably due to a reduction in the esterified moiety, since liver FC measures were unchanged. Training resulted in significantly lower TC concentrations in the selected tissues studied even though specific activity curves appeared similar for both groups. Our conclusions are that lipid metabolic adaptation; studied in vivo, occurs in tissues with training, but that these adaptations are not uniform across tissues, lipid moieties, or measurement parameters.

Acetates

Diabetes among men in a general population. Prevalence and associated physiological findings.

A random sample of 281 men, aged 30 through 69, resident in the community of Tecumseh, Mich, was studied with the use of standard glucose tolerance tests, including serum insulin assays and fasting serum lipid concentrations. Diagnoses of diabetes and probable diabetes were made according to a modification of the criteria of Fajans and Conn. Prevalence of diabetes and probable diabetes was considerably higher among men aged 40 through 49 than among those aged 30 through 39, but it increased little in the 50-through-59 and 60-through-69 age groups. Lean nondiabetics and probable diabetics had similar mean systolic blood pressures and similar mean levels of serum cholesterol, serum triglycerides, and serum insulin, but fat probable diabetics had much higher mean serum lipid and serum insulin concentrations that fat nondiabetics. Adiposity grouping discriminated by variable levels less well between diabetics and nondiabetics.

Adult