Atherosclerosis begins in childhood as deposits of cholesterol and its esters, referred to as fatty streaks, in the intima of large muscular arteries. In some persons and at certain arterial sites, more lipid accumulates and is covered by a fibromuscular cap to form a fibrous plaque. Further changes in fibrous plaques render them vulnerable to rupture, an event that precipitates occlusive thrombosis and clinically manifest disease (sudden cardiac death, myocardial infarction, stroke, or peripheral arterial disease). In adults, elevated non-HDL-cholesterol concentrations, low HDL-cholesterol concentrations, hypertension, smoking, diabetes, and obesity are associated with advanced atherosclerotic lesions and increased risk of clinically manifest atherosclerotic disease. Control of these risk factors is the major strategy for preventing atherosclerotic disease. To determine whether these risk factors also are associated with early atherosclerosis in young persons, we examined arteries and tissue from approximately 3000 autopsied persons aged 15-34 y who died of accidental injury, homicide, or suicide. The extent of both fatty streaks and raised lesions (fibrous plaques and other advanced lesions) in the right coronary artery and in the abdominal aorta was associated positively with non-HDL-cholesterol concentration, hypertension, impaired glucose tolerance, and obesity and associated negatively with HDL-cholesterol concentration. Atherosclerosis of the abdominal aorta also was associated positively with smoking. These observations indicate that long-range prevention of atherosclerosis and its sequelae by control of the risk factors for adult coronary artery disease should begin in adolescence and young adulthood.

Improved quality of images and regaining of the control gray values of a phantom were achieved when the MAR algorithm was used in the presence of a metallic bead.

Using the baboon as a model, we tested the hypothesis that preweaning food intake influences the number of adipocytes at weaning. Two groups of 12 newborn baboons each were fed either a concentrated or a diluted Similac formula from birth to 18 weeks of age. Baboons fed the concentrated Similac were 38% heavier (P less than 0.01) and had 87% more fat mass (P less than 0.01) than the baboons fed diluted Similac. The mean adipocyte volume and adipocyte number were measured directly in 10 individual fat depots, and the total number of adipocytes were estimated for each baboon. The difference in fat mass was due to differences (P less than 0.01) in mean adipocyte volume, which was 0.22 nl in overfed baboons and 0.09 nl in underfed baboons. There was no significant diet effect on the estimated total number of fat cells; nor on 8 of 10 depots in which adipocyte number was directly measured. These results indicate that, in baboons, preweaning caloric intake has little or no influence on the number of fat cells at the age of weaning.

Mexican Americans, a group at high risk for type II diabetes mellitus, have higher postprandial insulin and glucose levels when compared to non-Hispanic whites. A rapid rate of gastric emptying contributes to an increased rate of nutrient absorption and subsequent greater elevation of postprandial glucose and insulin levels. A more rapid rate of gastric emptying and hyperinsulinemia have been observed in patients with recently diagnosed type II diabetes mellitus. In this study, we examined whether Mexican Americans have a more rapid rate of gastric emptying than non-Hispanic whites. Gastric emptying studies were performed on 32 nondiabetic Mexican Americans and on 31 nondiabetic non-Hispanic whites. The rate of gastric emptying following a liquid glucose meal was measured. Serum insulin, plasma glucose, and GIP levels were measured in fasting and postprandial blood samples collected at 15-min intervals for 2 hr. Adjusting for age, body mass index, and gender, the gastric half-emptying time of a glucose meal was significantly (P < 0.05) more rapid for the Mexican American subjects (56.5 +/- 3.4 min) compared to the non-Hispanic white subjects (66.4 +/- 3.5 min). Nondiabetic Mexican Americans empty a liquid glucose meal more rapidly from their stomachs than nondiabetic non-Hispanic whites. Rapid gastric emptying is associated with hyperinsulinemia as a normal physiologic response to increased nutrient availability. The rapid gastric emptying observed in nondiabetic Mexican Americans is associated with hyperinsulinemia and could be a contributing factor for the increased risk of obesity and type II diabetes in this population.

The hypothesis that energy intake influences differently the composition of mass gain during the preweaning period was tested in male and female baboons. Infant baboons were fed either a high (92 kcal/100 g formula) or a low (49 kcal/100 g formula) caloric formula from birth. Body mass, lean body mass and fat mass of each baboon were measured directly at weaning (18 weeks of age). Lean mass and fat mass gained from birth to 18 weeks was estimated by using body composition data from eight newborn baboons. Both energy intake and gender significantly influenced gain of total mass, lean mass and fat mass. There was a significant gender by diet interaction effect on the gain of fat mass. When fed the high caloric formula, males gained 145 g more lean mass than females, but the increase of fat mass was approximately the same. In contrast, on the low caloric formula, males gained 150 g more lean mass than females but 74 g less fat mass than females. These results indicate that fundamental differences in the development of lean mass and fat mass exist between male and female baboons during preweaning life.

No abstract