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Biomedical subjects

E J Schaefer

Publications and source records attributed to E J Schaefer.

At least 325 records · Page 18Linked to original sources
PubMed1980

Changes in plasma lipids and lipoproteins after a modified fat diet.

20 male and female patients with type II hyperlipoproteinaemia and 10 normal male and female subjects were fed for 11--15 days a eucaloric diet containing less than 300 mg cholesterol with a polyunsaturated to saturated fatty-acid ratio of about 2.0. Male subjects and patients and female patients showed statistically significant decreases in plasma total cholesterol and low-density lipoprotein (LDL) cholesterol levels; the change in LDL-cholesterol was not significant in female subjects. The changes in lipid and lipoprotein levels in patients were greater than those in subjects, (except for the changes in high-density lipoprotein (HDL) in women, which were similar), which suggested that the magnitude of change depended on initial levels. This difference was not present when the data were evaluated as percent change. Mean levels of HDL-cholesterol decreased in both patients and subjects. However, the proportion of total cholesterol contributed by HDL and LDL, and hence the HDL/LDL ratio, was unchanged from pre-diet levels.

Adult↗
PubMed1980

Effect of exercise conditioning on plasma high density lipoproteins and other lipoproteins.

Epidemiologic studies have demonstrated an inverse correlation between HDL-cholesterol and the incidence of coronary artery disease. Although physically active individuals tend to have higher HDL levels than their sedentary peers, they also have lower body weights. It has yet to be shown that physical activity by itself can raise HDL when other variables such as body weight are maintained constant. We examined the effect of a 6-week exercise conditioning program on 10 young normal subjects who were maintained on a constant composition, iso-weight diet. A training effect was documented by an increase in maximum oxygen consumption from 44 to 49 ml/min/kg and by a fall in heart rate at submaximal exercise from 120 to 109 beats/min. Total plasma cholesterol levels decreased significantly from 156 to 140 mg/dl. However, there was no significant change in plasma triglyceride, VLDL, LDL or HDL-cholesterol levels, although all these values decreased. Thus, under the conditions of this study in which diet and weight were controlled, exercise conditioning did not elevate HDL-cholesterol levels. HDL levels have been shown to be inversely related to body weight. These data are consistent with the concept that exercise conditioning may affect HDL via alterations in body weight.

Adult↗
PubMed1979

Ocular manifestations of familial high-density lipoprotein deficiency (Tangier disease).

Corneal clouding is one of the manifestations of Tangier disease, an inherited disorder in which cholesterol-rich lipids are deposited in various tissues of the body. The cause of the corneal clouding is unknown. This study documents the clinical course and conjunctival biopsy findings of a 60-year-old man who was one of the earliest patients to be recognized with Tangier disease and in whom progressive corneal clouding developed in adult life. Noteworthy in the biopsy specimens were birefringent lipid particles that were predominantly present in degenerating pericytes of the conjunctival vessels.

Arteries↗
PubMed1979

The composition and metabolism of high density lipoprotein subfractions.

The composition and metabolism of high density lipoprotein (HDL) subfractions were investigated in seven normal individuals. Mean HDL2 (d, 1.063-1.125 g/ml) composition (by weight) was 43% protein, 28% phospholipid, 23% cholesterol, and 6% triglyceride, and mean HDL3 (d, 1.125-1.21 g/ml) composition was 58% protein, 22% phospholipid, 14% cholesterol, and 5% triglyceride. The mean apoA-I; apoA-II weight ratio was 4.75 for HDL2 and 3.65 for HDL3. HDL2 protein was proportionally slightly richer in C apolipoproteins and higher molecular weight constituents (including apoE) than HDL3. Kinetic studies utilized radiolabeled HDLA (d, 1.09-1.21 g/ml), HDL2, and HDL3 demonstrated rapid exchange of apoA-I and apoA-II radioactivity among HDL subfractions, similar fractional rates of catabolism of apoA-I and apo A-II within HDL, and similar radioactivity decay within HDL subfractions. Mean plasma residence time was 5.74 days for radiolabeled HDL2 and 5.70 days for radiolabedled HDL3. Differences in HDL protein mass among individuals were largely due to alterations in catabolism, and in general both HDL2 and HDL3 were catabolized via a plasma and a nonplasma pathway. Data from simultaneous radiolabeled very low density lipoprotein and HDL studies in 2 individuals are consistent with the concept that apoC-II and apoC-III are catabolized at a different rate than are apo A-I and apo A-II within the HDL density range.

Adult↗
PubMed1978

Metabolism of high-density lipoprotein apolipoproteins in Tangier disease.

To define the metabolic defect in Tangier disease, we studied the kinetics of [125I]-high-density lipoprotein apolipoproteins (apolipoproteins A-I and A-II) in 11 normal subjects, two obligate heterozygotes, and two homozygotes. Mean synthesis of apolipoproteins A-1 and A-11 was 8.24 mg per kilogram per day in the normal group, 7.94 in heterozygotes and 3.66 in homozygotes. The mean plasma-residence time for both apolipoproteins was 5.21 days in the normal subjects, 3.41 days in heterozygotes, and 0.52 days in homozygotes. In normal subjects and heterozygotes the apolipoproteins were catabolized at similar rates, whereas in homozygotes apolipoprotein A-I was catabolized at a much greater fractional rate than apolipoprotein A-II. These findings indicate that the deficiency of these apolipoproteins in Tangier disease is largely due to rapid and altered catabolism.

Adult↗
PubMed1978

Plasma-triglycerides in regulation of H.D.L.-cholesterol levels.

Plasma-high-density-lipoprotein (H.D.L.) cholesterol concentrations are lower in patients with coronary-artery disease than in control subjects. In an investigation of the relationship of H.D.L. cholesterol to other lipid and lipoprotein parameters in normal and hyperlipoproteinaemic subjects inverse correlations were found between H.D.L. cholesterol and very-low-density-lipoprotein (V.L.D.L.) cholesterol, and between H.D.L. cholesterol and plasma-triglyceride levels. Mean H.D.L.-cholesterol concentrations in normal subjects were 50 mg/dl, and in hyperlipoproteinaemic patients they were: type I, 17 mg/dl; type II, 44 mg/dl; type III, 38 mg/dl; type IV, 37 mg/dl; and type V, 27 mg/dl. H.D.L.-cholesterol levels were lowest in patients with fasting chylomicronaemia and were diminished in hypertriglyceridaemic subjects, suggesting a relationship between the metabolism of triglyceride-rich lipoproteins and H.D.L.

Cholesterol↗
PubMed1976

Socioeconomic factors and maternal and child health care.

A sample of mothers was interviewed between 12 and 18 months after delivery of a liveborn infant. Data were gathered concerning planned parenthood, prenatal care, the child's care in the first year of life, and socioeconomic factors. Among socioeconomic variables, maternal education was found to be the single best parameter in terms of detecting differences within the sample with regard to levels of birth control, prenatal care, and child care.

Child Health Services↗
PubMed1976

Treatment of protein-losing gastropathy with atropine.

Protein loss from the gastric mucosa with hypertrophic gastric folds and hypoalbuminemia has been associated with low, normal and elevated gastric acid output. A case of protein-losing gastropathy with slightly elevated gastric acid output is described. Associated findings were hypertrophic gastric folds, hypoalbuminemia, hyperlipidemia, lymphadenopathy, edema, ascites and venous thrombosis. Oral administration of atropine resulted in a cessation of gastrointestinal protein loss and correction of hypoalbuminemia.

Acids↗
PubMedDate not supplied

Multicenter evaluation of a patient-administered test for blood cholesterol measurement.

BACKGROUND: In order to assess accuracy of a newly developed, noninstrumented, self-administered fingerstick test that measures cholesterol levels in whole blood, the AccuMeter Cholesterol Self-Test was evaluated for home-use by untrained consumers in a multicenter study. METHODS: A total of 486 untrained adult volunteers of varying age, occupation, and educational background were recruited at four sites. Participants received written instructions provided in the kit, access to a telephone "800" number for additional help, and, if necessary, a short instructional video available to consumers on request. Fingerstick cholesterol results obtained by untrained volunteers were compared with paired venous serum results obtained by the Abell-Kendall cholesterol reference method. After application of exclusion criteria, 79.0% (384/486) of subjects had AccuMeter fingerstick results available for comparison with the reference method. RESULTS: Results obtained with the AccuMeter test correlated well with the Abell-Kendall results (r = 0.91). There was a mean overall bias for the AccuMeter of -0.116 +/- 0.528 mmol/liter (-2.2%), with a mean absolute bias of 0.398 +/- 0.367 mmol/liter (7.6%). Biases at the National Cholesterol Education Program cutpoints of 5.20 and 6.20 mmol/liter were -2.2 and -2.5%, respectively. Subjects with high-risk total cholesterol values (> or = 6.20 mmol/liter) were correctly classified 80.0% of the time, with an additional 18.8% placed in the borderline category (5.20-6.20 mmol/liter); 1.2% were inappropriately placed in the desirable category. No subjects were placed in the high-risk category by the AccuMeter test if they had a desirable cholesterol value by the reference method, while 9.8% were placed in this category if they were in fact borderline. CONCLUSIONS: This test appears to be a useful addition to available options in the effort to increase awareness of cholesterol as a heart disease risk factor. A large portion of untrained consumers were able to perform the AccuMeter Cholesterol Self-Test and obtain comparable results to the reference method. This test for the first time allows consumers to determine their own cholesterol values, with a reasonably good degree of accuracy.

Adolescent↗
PubMedDate not supplied

Effect of response to a low-fat diet among adolescent males on their adult blood cholesterol levels.

BACKGROUND: While primary prevention of adult cardiovascular diseases should begin early, there are problems in identifying children at increased risk of future disease. METHODS: We did a follow-up study in 1991-1992 of 100 male former students at a boarding high school who had blood cholesterol measured in 1970-1971 both prior to and following a school-wide, reduced-fat dietary intervention. We compared adult cholesterol levels of the 50 subjects whose cholesterol decreased > or = 16.5% (the median decrease) following the 1970-1971 intervention (Diet-Sensitive) with the 50 whose response was < 16.5% (Non-Diet-Sensitive). RESULTS: Blood cholesterol of adults who were Diet-Sensitive in 1970-1971 was 4.2 mg/dl lower than their baseline values in adolescence, while adults classified as Non-Diet-Sensitive as adolescents showed a 15.9 mg/ dl increase in cholesterol over 21 years. Adjusting for baseline adolescent values, Non-Diet-Sensitive subjects were 4.8 (95% CI 1.4, 15.9) times as likely as Diet-Sensitive subjects to have adult cholesterol > or = 200 mg/ dl. Also, Diet-Sensitive adults on a low-fat diet had adult blood cholesterol levels > 20 mg/dl lower than Non-Diet-Sensitive adults on a similar diet (180.1 vs 202.1 mg/dl, respectively). CONCLUSIONS: Degree of response to a low-fat, low-cholesterol diet during adolescence may identify male subjects who will have differing patterns of cholesterol change over time.

Adolescent↗
PubMedDate not supplied

Biomass and aggregation analysis of human embryonic kidney 293 suspension cell cultures by particle size measurement.

A method has been developed to monitor the cell growth of aggregated human embryonic kidney 293 (HEK293) suspension cultures by measuring cumulative particle volume and the particle size distribution. This method employs a particle size analyzer that determines the size of individual particles by detecting their light obscuration (blockage) or scattering. Cell counts derived from the cumulative volume of the cell particle correlate well with manual cell counts from a hemacytometer at different stages of growth. This correlation was further confirmed by quantifying total cellular protein of the samples. Simultaneously, the aggregation state of the samples can also be monitored and mathematically described. Results from this study demonstrate that this simple and reproducible method allows the direct measurement of cumulative cell volume and the degree of cell aggregation, as well as an indirect assessment of cell counts.

Biomass↗
PubMedDate not supplied

Platelet function and survival in patients wit severe hypercholesterolemia.

Platelet aggregation and survival were measured in twelve subjects with severe hypercholesterolemia. There was a small increase in sensitivity to epinephrine and adenosine diphosphate among the most hypercholesterolemic patients, but this did not correlate with reduced platelet lifespan. Platelet survival was normal or only moderately reduced in the markedly hypercholesterolemic homozygous subjects. However, the incidence of reduced platelet survival was significantly increased (p less than 0.05) among the older patients with more extensive atherosclerotic vascular disease compared to the younger patients with limited vascular disease. Marked hypercholesterolemia in the absence of atherosclerosis does not appear to accelerate platelet destruction, although a modest increased aggregability is present.

Adolescent↗