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Biomedical subjects

C G Hames

Publications and source records attributed to C G Hames.

At least 73 records · Page 4Linked to original sources

Segregation and linkage analyses of dopamine-beta-hydroxylase activity.

Dopamine-beta-hydroxylase (DBH) activity in serum was measured by spectrophotometric methods in 95 persons of a large family (HGAR 2), along with 27 polymorphic markers from blood, urine and saliva. The distribution of DBH activity, after appropriate transformation and age adjustment, showed a significantly better fit to a mixture of two normal distributions than a single normal distribution. Pedigree segregation analyses showed evidence of a possible major gene governing low levels of DBH activity, segregating in this family in a recessive fashion. Linkage analyses between that major locus and the 27 polymorphic markers showed no significant lod scores favoring linkage. The highest lod score obtained was 0.81 with Lp at zero recombination fraction. In addition, published data on DBH activity measured by radiochemical assays on 22 families with 161 members were reanalyzed as a quantitative trait, with appropriate correction for ascertainment bias. The results were similar to that of HGAR 2, corroborating the existence of a major locus for DBH activity.

Adult↗

The combined effect of smoking and coffee drinking on LDL and HDL cholesterol.

Conflicting reports on the effect of smoking and coffee drinking on lipoproteins prompted us to study the combined effect of these two associated, widely prevalent habits in 361 persons randomly sampled from the Evans County cohort. Low-density lipoprotein (LDL) cholesterol levels were significantly higher among persons who smoked cigarettes and consumed five or more cups of coffee per day than among nonsmokers who abstained from coffee. Conversely, high-density lipoprotein (HDL) cholesterol was higher in persons who did not smoke or drink coffee than in coffee-consuming smokers. However, this trend was not statistically significant. Triglycerides and very low-density lipoprotein (VLDL) cholesterol were highest among smokers who drank five or more cups of coffee per day, but these differences did not reach statistical significance. Lipoprotein cholesterol levels were adjusted for age, sex and body mass. Smoking and coffee drinking interact in affecting LDL and total cholesterol, but coffee drinking alone did not appear to affect blood lipids.

Age Factors↗

Frequency of church attendance and blood pressure elevation.

Blood pressure levels were examined with regard to church attendance patterns in a group of white male heads of households who appeared in the 1967-1969 follow-up examination of the Evans County Cardiovascular Epidemiologic Study. A consistent pattern of lower systolic and diastolic blood pressures among frequent church attenders was found compared to that of infrequent attenders which was not due to the effects of age, obesity, cigarette smoking, or socioeconomic status.

Age Factors↗

Abnormal T cell subpopulations and circulating immune complexes in the Guillain-Barré syndrome and multiple sclerosis.

Immunologic studies were performed in 21 patients with multiple sclerosis (MS) and 16 with the Guillain-Barré syndrome (GBS). Levels of thymus-derived (T) cells measured by "total" and "active" rosette formation between sheep erythrocytes and peripheral blood mononuclear cells (TEt, TEa) were within normal limits in all the patients, with the exception of four GBS patients, including one who also had received chemotherapy for lymphoma and three who were receiving steroids. When lymphocytes from the 21 patients were incubated with the bone-marrow-derived (B) lymphoblastoid cell line PGLC-33H, there were, for 12 of 18 MS patients and 11 of 16 GBS patients, significant decreases in a subpopulation of peripheral blood T lymphocytes that form "PGLC rosettes" (PGR) with the PGLC-33H cells. (Peripheral blood T cells from normal individuals formed PGR with 23.9 +/- 3.8 percent of PGLC-33H cells.) Using the 125l-C1q binding assay, immune complexes were detected in the serum of 14 of 19 MS patients and 15 of 16 GBS patients. An association between increased C1q binding and decreased PGR values was found in 10 of 18 MS patients and 12 of 17 GBS patients. The results suggest that in both diseases the etiology may involve a decrease in the subset of T cells that bind to the IgM-producing cell line PGLC-33H, in association with the appearance of circulating immune complexes containing the infectious viral agent.

Antigen-Antibody Complex↗

Coffee consumption and mortality. Total mortality, stroke mortality, and coronary heart disease mortality.

Total mortality showed no association with coffee usage in the four race-sex groups of Evans County, Georgia. Deaths of coronary heart disease (CHD) in white men and women and black men showed no statistically significant difference between high and low coffee consumers. In an area that has been designated as the "Stroke Belt," neither CHD nor cerebrovascular death rates seem related to coffee-drinking habits. However, to refute or confirm the allegations of a detrimental influence of high coffee intake, larger samples are needed. Nevertheless, our finding that mortality from all causes is not increased in the high coffee-consuming group means that a finding of increased CHD mortality with high coffee consumption would have to be compensated by a protective lower rate for other causes of death.

Adult↗

The influence of increased dietary linoleate on essential hypertension in man.

A pilot study testing the hypothesis of a blood pressure lowering effect of polyunsaturated fatty acids was conducted in Evans County, Georgia. A moderate increase of dietary linoleic acid significantly decreased diastolic blood pressure in eight borderline hypertensives who were otherwise healthy, within four weeks. The change was not due to a reduced sodium content of the diet. A significant increase in creatinine excretion and clearance was noted, indicating an improvement in kidney function which might explain the blood pressure lowering effect of the fat-modified diet.

Adult↗

Alcohol and blood lipids. The cooperative lipoprotein phenotyping study.

Data from five study populations participating in the Cooperative Lipoprotein Phenotyping Study indicate strong relations between reported alcohol consumption and blood-lipids. Alcohol consumption was positively associated with high-density-lipoprotein cholesterol level in all populations (r from 0-16 to 0-30), the lipid level appearing to be a graded response even over the low levels of alcohol consumption reported. Less strong but consistently negative correlations were found with low-density-lipoprotein cholesterol. Plasma-triglycerides showed a modest positive correlation with alcohol. The five populations were those of the Albany, Evans County, Framingham, Honolulu, and San Francisco Studies.

Aged↗

HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study.

The relation between coronary heart disease (CHD) prevalence and fasting lipid levels was assessed by a case-control study in five populations with a total of 6859 men and women of black, Japanese and white ancestry drawn from subjects aged 40 years and older from populations in Albany, Framingham, Evans County, Honolulu and San Francisco. In each major study group mean levels of high density lipoprotein (HDL) cholesterol were lower in persons with CHD than in those without the disease. The average difference was small -- typically 3-4 mg/dl -- but statistically significant. It was found in most age-race-sex specific groups. The inverse HDL cholesterol-CHD association was not appreciably diminished when adjusted for levels of low density lipoprotein (LDL) cholesterol and triglyceride. LDL, totoal cholesterol and triglycerides were directly related to CHD prevalence; surprisingly, these findings were less uniformly present in the various study groups than the inverse HDL cholesterol-CHD association.

Adult↗

Coffee consumption and mortality in a community study--Evans Co., Ga.

Total mortality showed no association with heavy coffee consumption in the four race-sex groups of Evans County. Deaths from coronary heart disease in WM, WF and BM showed no statistically significant differences between the two coffee consuming groups. Sex differences in cerebrovascular death rates, consistent in both races, suggest the possibility for a female excess of stroke deaths among coffee drinkers, and a "protective" effect of coffee drinking among males. Thus, in an area of the United States which has been designated the "Stroke Belt", neither the cardiovascular nor the cerebrovascular death rates seem strongly nor consistently related to coffee drinking habits. Although the number of deaths (339) is fairly large, representing a 13% mortality in this community over a four and one-half year observation period, the classification in four race-sex groups with further division into the groups with different coffee drinking habits limits each stratum to rather small numbers. In addition, 86 cases of CHD and CVD were diagnosed during lifetime already and, therefore, were excluded from the prospective mortality study. Confidently to refute or confirm the allegations of a detrimental influence of high coffee intake on ischemic heart disease one would need larger numbers. But in the light of our most important finding--that mortality from all causes is not increased in the high coffee consuming group--the finding of increased ischemic heart disease death rates with high coffee consumption would have to be compensated by a provocative, lower rate for other causes of death.

Black People↗

Influence of race, sex and weight on blood pressure behavior in young adults.

This study is concerned with blood pressure behavior in young adults (aged 15 to 29 years) in the biracial community of Evans County, Ga., on two occasions 7 years apart. On the basis of casual blood pressure recordings the prevalence of systolic pressure equal to or greater than 140 mm Hg or diastolic pressure equal to or greater than 90 mm Hg, or both, showed race/sex differences as follows: white males 19.0 percent, white females 12.7 percent. black males 34.0 percent, black females 31.6 percent. Similar differences were noted in the incidence during the 7 year interval. The problem presented by the variability of the casual blood pressure recording is apparent in this interval study. Of particular interest is the association of weight with blood pressure in this youthful group, particularly among white males and females and black females, in relation to both initial and subsequent pressure levels. The data suggest that in this population under 30 years, weight is a risk factor for hypertension, and that maintenance of ideal weight, instituted in youth, may be a preventive measure.

Adolescent↗

Blood platelet aggregation and personality traits.

Changes in blood platelet aggregation may precipitate episodes of arterial occlusive diseases. Little is known, however, regarding the influence of psychological traits, emotional states and other behavioral stressors on platelet aggregation phenomena. This study examined 46 healthy college men at rest and after submaximal treadmill exercise. Associations were found between the duration of platelet aggregation and a number of scores from the California Psychological Inventory and self-administered anxiety scales. The more socially adequate, poised and dominant persons--those with more mature ego development and less overt anxiety--had platelets with more prolonged aggregation reactions to the in vitro introduction of noradrenalin. Irreversible aggregation of platelets occurred more regularly to lower in vitro concentrations of noradrenalin in platelet samples drawn from subjects who were less anxious and tended to be more rigidly defensive. It is premature to attempt to derive clinical implications from this exploratory work, but some implications for the design of future research are discussed.

Adult↗

Prevalence and incidence data in the assessment of the risk of coronary heart disease.

Estimates of risk of coronary heart disease (CHD) derived from two prevalence survey examinations and from a 7- to 9-year incidence study were compared using data from the Evans County Cardiovascular study. Four risk factors were studied: sex, blood pressure, age and serum cholesterol; relative risks and morbidity ratios were used as estimators of the risk of CHD. Considerable agreement was found between the estimates of risk derived from the incidence and prevalence data.

Adult↗