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Biomedical subjects

W E Connor

Publications and source records attributed to W E Connor.

At least 181 records · Page 10Linked to original sources
PubMed1979

Effect of different dietary fats on daily loss of sterols from the skin of man.

We studied the effect of polyunsaturated dietary fat upon the 24-hour loss of cholesterol and other sterols from the skin surface of 4 human subjects. They were fed cholesterol-free diets which provided 40% of the total caloric intake from saturated fat (cocoa butter) and then a highly polyunsaturated fat (corn oil). In both dietary fat periods, the daily loss of cholesterol through the skin was similar, 91 and 87 mg in the saturated and polyunsaturated fat periods, respectively. 87 and 89% of the total cholesterol were in the esterified form in the saturated and polyunsaturated dietary fat periods. The sterol composition of the skin surface lipid was not altered. The study suggests that the plasma cholesterol-lowering effect of dietary polyunsaturated fat was not mediated by a change in the loss of cholesterol through human skin.

Adult↗
PubMed1979

Increased coronary mortality in relatives of hypercholesterolemic school children: the Muscatine study.

From 2,874 school children participating in the 1971 and 1973 Muscatine Coronary Risk Factor Survey, we selected three groups of index cases for detailed family study: the HIGH group (n = 56), with cholesterol levels greater than the 95th percentile twice; the MIDDLE group (n = 46), cholesterol levels between the 5th and 95th percentile; and the LOW group (n = 46), cholesterol levels less than the 5th percentile twice. Coronary mortality determined from death certificates was increased in the young relatives (ages 30-59) of the HIGH group index cases, as follows: twofold excess in HIGH male relatives compared with the MIDDLE or LOW group (p less than 0.05); tenfold excess in the HIGH female relatives compared with the MIDDLE and LOW group combined (p less than 0.01). After correction for years at risk, there was an approximately twofold significantly-increased coronary mortality. Stroke mortality was higher, although not significantly, in the older relatives (ages greater than or equal to 60) of the HIGH index cases. Cancer mortality was not significantly different among the relatives of the three groups of index cases. This study indicates that school children's cholesterol levels cluster with those of their family members and that persistent hypercholesterolemia in children identifies families at risk for coronary artery disease.

Adolescent↗
PubMed1979

Elevated cholesterol and bile acid synthesis in a young patient with homozygous familial hypercholesterolemia.

Cholesterol balance studies were carried out twice in a young male patient with homozygous familial hypercholesterolemia. At 13 mo, cholesterol balance in this patient averaged 31.3 mg/kg per d, and bile acid excretion was 12.0 mg/kg per d; at 3 yr, results were similar, 27.3 and 15.5 mg/kg per d for cholesterol balance and bile acids, respectively. A normal boy of 3 yr was also studied for comparison with the second study in our patient. Cholesterol balance and bile acid outputs in the normal child were 11.5 and 3.3 mg/kg per d, respectively. Thus, in comparison with the normal child, the patient with homozygous familial hypercholesterolemia had a marked increase in synthesis of cholesterol and bile acids. Although synthesis of bile acids was high in this patient, the fraction of newly synthesized cholesterol converted into bile acids (40-56%) was in the normal range; this suggests that the enhanced output of bile acids was secondary to an increased synthesis of cholesterol and not to malabsorption of bile acids, which likely would have produced a higher fractional conversion. Although our patient has been studied at a younger age than any reported in the literature, two similar children 5 and 6 yr of age were also observed to have elevated cholesterol synthesis. This finding contrasts with those in older children with the homozygous as well as heterozygous forms of this disease who appear to have normal synthesis of cholesterol and bile acids. Therefore, increased synthesis of cholesterol seems to be characteristic of early homozygous familial hypercholesterolemia, and may be a manifestation of a loss of feedback inhibition of cholesterol synthesis secondary to an absence of specific cell-surface receptors for low density lipoproteins. However, as children with this disease grow older, other mechanisms may come into play to restore cholesterol synthesis to normal levels.

Bile Acids and Salts↗
PubMed1979

The cholesterol turnover, synthesis, and absorption in two sisters with familial hypercholesterolemia (type IIa).

To explore the mechanisms of the profound plasma cholesterol elevations in familial homozygous hypercholesterolemia (type IIa), cholesterol turnover, sterol balance, cholesterol absorption, and low density lipoprotein studies were carried out under controlled dietary conditions in two sisters (aged 13 and 16). Cholesterol turnover was prolonged. The half-life of the first exponential of the plasma cholesterol specific activity decay curve was double that of normal adults. The rate constants for the removal of cholesterol from pool A (KAA = 0.0652) and for the excretion of cholesterol from the system (Kaa = 0.0197) were less than half of normal. The production rates of cholesterol were low, only 6.30 and 6.86 mg/kg per day as measured by cholesterol turnover and sterol balance techniques, respectively. Fecal neutral steroid and bile acid excretion were 5.22 and 1.64 mg/kg per day, which is remarkably low in comparison to those of normal and heterozygous children. Cholesterol absorption was within the upper limit of the values reported for normal adults. THE HDL cholesterol values were extremely low (27 mg/dl) in contrast to profoundly elevated LDL levels. The fractional catabolic rate of LDL (0.127 per day) and the rate of synthesis and catabolism of apo-LDL (15 mg/kg per day) were low in comparison to previously reported values in homozygotes. These composite data indicated that the definable metabolic defects of these two sisters with homozygous familial hypercholesterolemia were the sluggish clearance of cholesterol from the body coupled with low total body synthesis of cholesterol.

Absorption↗
PubMed1978

Tracking of blood lipids and blood pressures in school age children: the Muscatine study.

In four cross sectional school screens, the Muscatine Study has sampled 8,909 school children; 820 have been studied repeatedly over a six-year period. Tracking of measurements described by the relationship between repeated observations and the relationship between peer rank orderings over the six-year period has been studied. For height and weight, correlations between observations six years apart were approximately 0.74 and about 60% of children initially in the upper quintile were there again six years later. Six-year correlations were 0.65 for skinfold and 0.61 for cholesterol. Four-year correlation for fasting triglyceride was 0.40. Six-year correlations were 0.30 for casual systolic blood pressure and 0.18 for diastolic blood pressure. Peer rank orderings for both blood pressures were highly variable. Height and weight track well, and thus routine measurement of these variables are useful in identifying children with growth perturbing disorders. Cholesterol and, to a lesser degree, triglycerides also track, and a significant proportion of children with initially high values demonstrated consistently high values throughout the study period. Blood pressures do not track as well; consistently high blood pressures are unusual, thus indicating the need for repeated blood pressure measurements to identify children with persistent elevated levels. The future significance of transient blood pressure elevations has yet to be established.

Adolescent↗
PubMed1978

The steroids of 2000-year-old human coprolites.

Six samples of human coprolites, some more than 2,000 years old, were analyzed for fecal steroid composition. Despite this very lengthy period of storage, the fecal steroids of coprolites were remarkably similar to those of stool samples collected today. The sterol nucleus was clearly rather stable under the dry environmental conditions of the Nevada Caves. The steroid content (microgram/g dried weight) of coprolite was low in comparison to that of modern man. The bile acid/cholesterol and plant sterol/cholesterol ratios of the coprolite, however, were similar to these ratios of the stools of modern man. In the six coprolites, an average 73% of the neutral steroids was digitonin-precipitable. This precipitate was composed of cholesterol and three plant sterols (campesterol, stigmasterol, and beta-sitosterol) and their bacteria-modified products. A portion of the neutral steroids had been converted to products tentatively identified as epimers of these steroids. Individual bile acids were identified in the coprolite. The bile acid composition of the coprolite was similar to that of the stool of modern man.

Cholic Acids↗
PubMed1978

Normal blood pressure and the evaluation of sustained blood pressure elevation in childhood: the Muscatine study.

This study describes the seated blood pressure distributions of 6,622 predominantly white schoolchildren in Muscatine, Iowa. Subjects with seated pressures equal to or greater than the 95th percentile for age and sex or 140 mm Hg systolic or 90 mm Hg diastolic were examined on repeated occasions. Approximately 13% of subjects were found to have blood pressures at these levels when first examined, but less than 1% were found to have persistent blood pressure elevations. Of 41 subjects found to have persistent blood pressure elevations, 23 were obese with relative weights in excess of 120%. Of the 18 lean subjects, 5 had secondary hypertension and 13 were considered to have essential hypertension. Mass screening of school-age children identifies many children with transient elevation of blood pressure and few with fixed high blood pressures. Children's blood pressures should be assessed during their continuing care where pressures can be measured over a period of time to identify those with fixed blood pressure elevations.

Adolescent↗
PubMed1977

Absence of the biochemical symptoms of essential fatty acid deficiency in surgical patients undergoing protein sparing therapy.

The biochemical symptoms of essential fatty acid deficiency appear within 7 to 10 days of fat-free total parenteral nutrition using glucose-amino acid mixtures. The linoleic acid (C18:2W6) content of all plasma lipid fractions decreases greatly and plasma eicosatrienoic acid (C20:3W9) increases. We have measured the fatty acid composition of the plasma lipid fractions in six surgical patients receiving parenteral nutritional solutions containing only amino acids, and completely free of glucose, before and after 10 to 14 days of such therapy. Biochemical symptoms of essential fatty acid deficiency did not occur. The fatty acid composition of all plasma lipid fractions remained unchanged after this time period. Mobilization of linoleic acid from the adipose tissue occurred with this treatment in contrast to the inhibition of lipolysis of adipose tissue triglyceride produced by continuous infusions of hypertonic glucose-amino acid mixtures.

Adult↗
PubMed1977

The interaction of dietary fibers and cholesterol upon the plasma lipids and lipoproteins, sterol balance, and bowel function in human subjects.

To identify any metabolic effects of dietary fiber upon cholesterol metabolism in man, six adult volunteer subjects were fed eucaloric cholesterol-free formula diets, with and without added dietary fiber for two 4-wk periods. A large quantity of dietary fiber was fed, some 60 g of plant cell wall material (or 16 g of crude fiber) derived from corn, beans, bran, pectin, and purified cellulose. This provided about five times the fiber intake of the typical American diet. The addition of fiber to the cholesterol-free diet did not change either the plasma cholesterol level (171+/-21 mg/dl, SEM, to 167+/-18) or the triglyceride (103+/-39 to 93+/-27 mg/dl). The excretion of both endogenous neutral steroids and bile acids were unchanged with fiber (505+/-41 to 636+/-75 mg/day and 194+/-23 to 266+/-47 mg/day, respectively.) However, total fecal steroid excretion was increased 699+/-29 to 902+/-64 mg/day, P < 0.025). With fiber, intestinal transit time was decreased (59+/-9 to 35+/-8 h, P < 0.005), and both the wet and dry stool weights were greatly increased.A second group of six subjects was fed similar diets containing 1,000 mg cholesterol derived from egg yolk. The addition of fiber to the 1,000-mg cholesterol diet did not alter either plasma cholesterol level (233+/-26 to 223+/-36 mg/dl) or triglyceride (102+/-19 to 83+/-11 mg/dl). The excretion of endogenous neutral steroids (618+/-84 to 571+/-59 mg/day), of bile acids (423+/-122 to 401+/-89 mg/day), and of total fecal steroids (1,041+/-175 to 972+/-111 mg/day) were unchanged by fiber. The absorption of dietary cholesterol was not altered when fiber was added to the 1,000-mg cholesterol diet (44.0+/-3.3 to 42.9+/-2.5%). A two-way analysis of variance utilizing both groups of subjects indicated a significant (P < 0.001) effect of dietary cholesterol upon the plasma cholesterol concentration. We concluded that a large quantity of dietary fiber from diverse sources had little or no effect upon the plasma lipids and sterol balance in man in spite of the fact that intestinal transit time and stool bulk changed greatly.

Adult↗