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Biomedical subjects

M C Oalmann

Publications and source records attributed to M C Oalmann.

At least 19 recordsLinked to original sources
PubMed2000

Associations of coronary heart disease risk factors with the intermediate lesion of atherosclerosis in youth. The Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group.

The raised fatty streak (fatty plaque) is the gross term for the lesion intermediate between the juvenile (flat) fatty streak and the raised lesion of atherosclerosis. We measured the percentage of intimal surface involved with flat fatty streaks, raised fatty streaks, and raised lesions in the aortas and right coronary arteries of 2876 autopsied persons aged 15 through 34 years who died of external causes. Raised fatty streaks were present in the abdominal aortas of approximately 20% of 15- to 19-year-old subjects, and this percentage increased to approximately 40% for 30- to 34-year-old subjects. Raised fatty streaks were present in the right coronary arteries of approximately 10% of 15- to 19-year-old subjects, and this percentage increased to approximately 30% for 30- to 34-year-old subjects. The percent intimal surface involved with raised fatty streaks increased with age in both arteries and was associated with high non-high density lipoprotein (HDL) and low HDL cholesterol concentrations in the abdominal aorta and right coronary artery, with hypertension in the abdominal aorta, with obesity in the right coronary artery of men, and with impaired glucose tolerance in the right coronary artery. Associations of risk factors with raised fatty streaks became evident in subjects in their late teens, whereas associations of risk factors with raised lesions became evident in subjects aged >25 years. These results are consistent with the putative transitional role of raised fatty streaks and show that coronary heart disease risk factors accelerate atherogenesis in the second decade of life. Thus, long-range prevention of atherosclerosis should begin in childhood or adolescence.

Adolescent↗
PubMed1998

Relation of a postmortem renal index of hypertension to atherosclerosis and coronary artery size in young men and women. Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group.

In a cooperative multicenter study, the Pathobiological Determinants of Atherosclerosis in Youth, we measured atherosclerosis of the aorta and right coronary artery (RCA) in 2403 black and white men and women 15 through 34 years of age who died of external causes and were autopsied in forensic laboratories. We measured the diameter of the opened, flattened, and fixed RCA and the diameter, intimal thickness, intimal cross-sectional area, medial thickness, and medial cross-sectional area of the pressure-perfused, fixed left anterior descending (LAD) coronary artery. Using the ratio of intimal thickness to outer diameter of the small renal arteries to predict mean arterial pressure during life, we classified the cases as normotensive (mean arterial pressure < 110 mm Hg) or hypertensive (mean arterial pressure > or = 110 mm Hg). The prevalence of hypertension by age, sex, and race corresponded closely with that measured in a survey of the living population. Hypertension had little or no effect on fatty streaks. Hypertension was associated with more extensive raised lesions in the abdominal aortas and RCAs of blacks > 20 years of age and in the RCAs of whites > 25 years of age. At all ages, women had less extensive raised lesions in the RCAs than did men, but the effect of hypertension on raised lesions was similar to that in men. Adjustment for serum lipoprotein cholesterol levels and smoking in a subset of cases yielded results similar to those obtained without adjustment. Hypertension was associated with larger diameters of the RCA and LAD coronary artery and with larger cross-sectional intimal and medial areas of the LAD coronary artery. Hypertension augments atherosclerosis in both men and women primarily by accelerating the conversion of fatty streaks to raised lesions beginning in the third decade of life, and the effect of hypertension increases with age.

Adolescent↗
PubMed1997

Atherosclerosis in youth: are hypertension and other coronary heart disease risk factors already at work?

The purposes of this review were to describe the natural history of atherosclerosis in youth, discuss the role of adult coronary heart disease (CHD) risk factors in the development of atherosclerosis-particularly in the young- and present the relationship between atherosclerosis and hypertension. Evidence is presented that, by age 15 years, 100% of the youth have aortic atherosclerosis and about one-half have coronary atherosclerosis. Risk factors for adult CHD, including lipoproteins, smoking, glycohemoglobin (a marker for diabetes), obesity, and hypertension, are associated with extent and prevalence of atherosclerosis in young people. Hypertension seems to play its role mainly by converting early atherosclerotic lesions (fatty streaks) to more advanced lesions (raised lesions).

Adolescent↗
PubMed1997

Effects of serum lipoproteins and smoking on atherosclerosis in young men and women. The PDAY Research Group. Pathobiological Determinants of Atherosclerosis in Youth.

Atherosclerosis begins in childhood and progresses from fatty streaks to raised lesions in adolescence and young adulthood. A cooperative multicenter study (Pathobiological Determinants of Atherosclerosis in Youth [PDAY]) examined the relation of risk factors for adult coronary heart disease to atherosclerosis in 1079 men and 364 women 15 through 34 years of age, both black and white, who died of external causes and were autopsied in forensic laboratories. We quantitated atherosclerosis of the aorta and right coronary artery as the extent of intimal surface involved by fatty streaks and raised lesions and analyzed postmorterm serum for lipoprotein cholesterol and thiocyanate (as an indicator of smoking). The extent of intimal surface involved with both fatty streaks and raised lesions increased with age in all arterial segments of all sex and race groups. Women had a greater extent of fatty streaks in the abdominal aorta than men, but women and men had about an equal extent of raised lesions. Women and men had a comparable extent of fatty streaks in the right coronary artery, but women had about half the extent of raised lesions. Blacks had a greater extent of fatty streaks than whites, but blacks and whites had a similar extent of raised lesions. VLDL plus LDL cholesterol concentration was associated positively and HDL cholesterol was associated negatively with the extent of fatty streaks and raised lesions in the aorta and right coronary artery. Smoking was associated with more extensive fatty streaks and raised lesions in the abdominal aorta. All three risk factors affected atherosclerosis to about the same degree in both sexes and both races. Primary prevention of atherosclerosis by controlling these adult coronary heart disease risk factors is applicable to young men and women and to young blacks and whites.

Adolescent↗
PubMed1996

Renovasculopathies of nephrosclerosis in relation to atherosclerosis at ages 25 to 54 years.

Renovasculopathies of hypertension include arteriolar hyalinization and arterial intimal fibroplasia. Atherosclerotic features of coronary arteries and aorta include fatty streaks and raised lesions. Data were obtained from a series of 573 autopsies of black and Caucasian males and females aged 25 to 54 years, who died of violent and natural causes unrelated to atherosclerosis. Analysis showed positive correlations of coronary and aortic raised lesions with arteriolar hyalinization. Arterial intimal fibroplasia correlated positively with raised lesions in the aorta but only weakly and inconsistently in the coronary arteries. The extent of fatty streaks in the coronaries, as in the aorta, did not correlate with either form of renovasculopathy. These results provide evidence that hyalinization of renal arterioles may be a marker for young people who have the most advanced coronary atherosclerosis, and who therefore have an early start upon a course toward coronary heart disease later in life.

Adult↗
PubMed1995

Environmental and genetic risk factors in early human atherogenesis: lessons from the PDAY study. Pathobiological Determinants of Atherosclerosis in Youth.

A multi-institutional study 'Pathobiological Determinants of Atherosclerosis in Youth' (PDAY) was initiated to document the natural history of atherosclerosis, its relationship to risk factors, and pathobiology of lesion development in young subjects. Pathology laboratories in nine centers collected arteries and tissues from over 2000 persons from 15 through 34 years of age whose deaths were attributed to homicides, accidents, or suicides. Arteries were evaluated for lesions, and risk factors were analyzed in a central laboratory. Post-mortem risk factors included serum lipoproteins, serum thiocyanate (smoking), glycohemoglobin (diabetes), thickness of panniculus adiposus (obesity), small renal artery changes (hypertension) and apoprotein isoforms. This study documents the development of atherosclerosis at an early age. It also shows that the recognized risk factors for coronary heart disease are associated with lesion development in the arteries of these young subjects. The PDAY study has a counterpart in Japan where the development of atherosclerosis has been studied in young subjects. This Japanese study, in a population in which coronary heart disease has not yet become a major epidemic, has findings quite similar to the findings from the PDAY study. Studies of atherosclerosis in both Japan and the USA provide strong justification for reducing risk factors in young persons.

Arteriosclerosis↗
PubMed1995

Relation of a postmortem renal index of hypertension to atherosclerosis in youth. The Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group.

In a cooperative multicenter study, Pathobiological Determinants of Atherosclerosis in Youth, of 1164 young men 15 through 34 years of age who died of external causes and were autopsied in forensic laboratories, we measured atherosclerosis of the aorta and the right coronary artery. Using the ratio of intimal thickness to outer diameter of the small renal arteries to predict mean arterial pressure (MAP) during life, we classified the cases as either normotensive (MAP < 110 mm Hg) or hypertensive (MAP > or = 110 mm Hg). By this criterion, the prevalence of hypertension in blacks was 16%; in whites, 12%. Hypertension was associated directly with blood level of glycohemoglobin (an indicator of blood glucose concentration) and with body mass index (BMI) but inversely with thickness of the panniculus adiposus. Among hypertensive compared with normotensive cases, the extent of raised lesions (mainly fibrous plaques) was greater in the aortas of 30- to 34-year-old men and in the right coronary arteries of 25- to 34-year-old men. The prevalence of raised lesions involving 5% or more of the intimal surface was twofold greater in the aortas and right coronary arteries of hypertensive men throughout the 15-to-34-year age span of the study cases. The association of hypertension with raised lesions was not accounted for by adjusting for glycohemoglobin level, BMI, or thickness of the panniculus adiposus. Hypertension is associated with accelerated atherosclerosis in youth.

Adipose Tissue↗
PubMed1995

Relation of glycohemoglobin and adiposity to atherosclerosis in youth. Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group.

In a cooperative multicenter study (Pathobiological Determinants of Atherosclerosis in Youth, PDAY) of 1532 young persons 15 through 34 years of age who died of external causes and were autopsied in medical examiners' laboratories, we quantified atherosclerosis of the aorta and the right coronary artery. We analyzed postmortem blood cells for glycohemoglobin and postmortem serum for lipoprotein cholesterol and thiocyanate (as an indicator for smoking). We measured the thickness of the panniculus adiposus and the body mass index (weight per height squared) as indicators of adiposity. Glycohemoglobin levels exceeding 8% were associated with substantially more extensive fatty streaks and raised lesions in the right coronary artery in persons more than 25 years of age and with more extensive raised lesions in the aorta in persons more than 30 years of age. Both thickness of the panniculus adiposus and body mass index were associated with more extensive fatty streaks and raised lesions in the right coronary artery. The associations of atherosclerotic lesions with glycohemoglobin and adiposity were not explained by a less favorable lipoprotein profile or smoking. The results show that atherosclerosis in young adults is associated with the prediabetic or early diabetic state, as indicated by elevated glycohemoglobin levels, and with obesity.

Adipose Tissue↗
PubMed1994

Nephrosclerosis, glycohemoglobin, cholesterol, and smoking in subjects dying of coronary heart disease.

Subjects dying of coronary heart disease (CHD) were compared with subjects in a control (basal) group in two series of forensic autopsies. Serum cholesterol assessed in postmortem heart blood was significantly greater in the CHD than in the basal group. CHD subjects were smokers more often than basal subjects, as determined from postmortem serum thiocyanate levels, but the statistical significance is ambiguous (P < 0.06). After exclusion of overt diabetics, a stepwise increase in the percentage of subjects with CHD was observed throughout the normal range for glycohemoglobin. Fibroplasia of small renal arteries, the most reliable postmortem proxy for hypertension, did not differ between CHD and basal groups. These results suggest that young (mean age 49.2 yr) black and white men and women classified from autopsy findings as having CHD as cause of death are often not hypertensive, but instead tend to be hyperlipidemic and glucose intolerant. A surprising result was that arteriolar hyalinization and arterial fibroplasia of the renal cortex often failed to parallel each other between groups of subjects. This was true in comparisons between black and white, male and female, blood cholesterol and glycohemoglobin groupings, and between CHD and basal subjects. This outcome suggests that hyalinization of renal arterioles is an especially reliable marker for CHD and that this association may not be mediated entirely through high blood pressure.

Adult↗
PubMed1993

Nephrosclerosis in three cohorts of black and white men born 1925 to 1944, 1934 to 1953, and 1943 to 1962.

The prevailing levels of blood pressure among black and white men of ages 25 to 54 years were examined by two independent approaches in this study. Data on blood pressure obtained in national health surveys (National Health and Nutrition Examination Surveys, NHANES) do not show any appreciable upward or downward trend between 1960 and 1980 in men of these ages. The histologic examination of kidney samples obtained from coroner's autopsies offers an indirect way of estimating the levels of blood pressure that prevail in populations because of statistical relationships between nephrosclerosis and blood pressure. Samples of kidney tissues archived in New Orleans from 1968 to 1986 were evaluated by quantitative morphometry for the severity of the renovasculopathies that accompany high blood pressure. The outcome showed no significant secular trend among black and white men, confirming blood pressure survey findings that show no change in the hypertensive status of the population. The black-white difference in incipient signs of hypertension was seen to be well-established by ages 25 to 34 years in all cohorts of New Orleans subjects, as well as in the NHANES survey data. These result suggest that the adolescent and young adult ages are especially important in establishing the black-white difference in hypertension.

Adult↗
PubMed1992

Early lesions of atherosclerosis in childhood and youth: natural history and risk factors.

This paper traces the development of knowledge concerning early lesions of atherosclerosis and the relationship to risk factors in children, youth, and young adults. Autopsy studies have shown that atherosclerosis begins in childhood with the appearance of aortic fatty streaks. Aortic fatty streaks of some degree are present in practically all individuals from every human population. Coronary fatty streaks begin to form in adolescence. Most persons 20-29 years of age have coronary fatty streaks of some degree, regardless of sex, race, or national origin. While fatty streaking is clinically harmless and potentially reversible, progression to fibrous plaques and more advanced lesions often leads to a critical stage of atherosclerosis in which clinical disease develops. Development of fibrous plaques begins in the 20s. The most recent studies of atherosclerosis in youth and young adults provide additional details to establish the relationship of these lesions to serum lipids and lipoproteins and other identified risk factors for atherosclerosis and coronary heart disease in adults. One report shows that microscopic counterparts of fatty streaks occur in the left anterior descending coronary artery in the majority of children 10-14 years of age. Over 5% have more advanced microscopic lesions at this age. Autopsy studies of youth have shown that serum total cholesterol and low-density lipoprotein cholesterol levels are strongly related to aortic fatty streaks and the very-low-density lipoprotein cholesterol levels are positively correlated to coronary artery fatty streaks. Finally, a definitive report indicates that serum lipoprotein cholesterol concentrations and smoking are important determinants of the early stages of atherosclerosis in adolescents and young adults.

Aging↗
PubMed1992

Renal microvascular features of hypertension in Japan, Guatemala, and the United States.

The finding of benign arteriolar nephrosclerosis at autopsy usually implies the prior existence of essential hypertension. It was found in this study that minor degrees of incipient nephrosclerosis in young people can be shown to correlate with seemingly trivial blood pressure elevations. In this study, autopsy tissues were used to assess the magnitude of early nephrosclerosis in five population groupings. A comparison of males in Tokyo, Japan, Guatemala, and New Orleans, La (blacks and whites); and females in Tokyo revealed significant differences among these populations. Blacks exceeded whites in New Orleans in the magnitude of incipient nephrosclerosis in all 10-year age groups from 15 through 24 years to 45 through 54 years. Guatemalan males were, on average, less affected than New Orleans whites in all age groups. The data for all males (age range, 15 through 54 years) in Tokyo revealed little difference in nephrosclerosis from those in New Orleans whites. Blood pressure data were obtained from reports of cross-sectional surveys in these five populations. Blood pressure in males varied across age x race subgroups in close parallel with nephrosclerosis (r = .90), implying that variation in blood pressure among groups of subjects is strongly nephrosclerosis linked, even at very young ages; findings for Tokyo females were aberrant in this correlation. The results suggest that the lifelong progression toward the hypertensive state begins in childhood, and that these beginnings are measurably in the population averages of both nephrosclerosis and blood pressure elevations. Moreover, population differences in these two commensurate measures of the early precursors of hypertension were found to be well established by the ages of 15 through 24 years and were sustained at least into the ages of 45 through 54 years. The years of adolescence are here brought under suspicion of special importance in setting the lifelong course toward the hypertensive state.

Adolescent↗
PubMed1991

Blood pressure and nephrosclerosis in black and white men and women aged 25 to 54.

Kidney samples obtained at autopsy were evaluated for nephrosclerosis by quantitatively measuring the severity of intimal fibroplasia in the interlobular arteries and counting the number of hyalinized arterioles. Most cases were obtained from the coroner and had violent causes of death; subjects with cardiovascular diseases were excluded. Blood pressures in Health Survey data were obtained from published sources. Measures of nephrosclerosis in 365 black and white men and women in age groups 25 to 34, 35 to 44, and 45 to 54 yr were examined by three-way Analysis of Variance (ANOVA). Blacks exceeded whites in fibroplasia at all ages and in both sexes; this excess was paralleled by mean blood pressure in all comparisons. White women were not different from white men in fibroplasia; black women significantly exceeded black men at all ages. Women had lower blood pressures than men when matched for age, race, and fibroplasia; the average magnitude of this difference was 5.5 mm Hg. Since women are known to have as much hypertensive disease as men after age 50 yr, it seems possible that the arterial fibroplasia seen in young women may represent progression toward the hypertensive state, even through blood pressure does not reveal the equality of the sexes in this respect until after menopause. Hence, in women arterial fibroplasia is seen to precede a later rise in blood pressure. Arteriolar hyalinization was greater in men than in women but did not differ significantly between races. Hyalinization did not consistently follow blood pressure in comparisons between subgroups of subjects.

Adult↗
PubMed1989

Fatty acid composition of adipose tissue in humans: differences between subcutaneous sites.

We compared the fatty acid composition of adipose tissue from three different sites, one deep-seated site (perirenal) and two subcutaneous sites (abdominal and buttock), in 143 autopsied adult humans aged 24-61 y. The proportion of saturated fatty acids was highest in the perirenal adipose tissue and lowest in buttock adipose tissue. The proportions of monounsaturated fatty acids in the three sites were in the reverse order. Linoleic and linolenic acids were similar in the three adipose-tissue sites, an important finding for those concerned about the essential fatty acids, which are solely derived from the diet. The results clearly show that the fatty acid composition of the two subcutaneous fat depots differ significantly. We conclude that abdominal fat is more saturated than buttock fat.

Abdomen↗