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Biomedical subjects

B A Kottke

Publications and source records attributed to B A Kottke.

At least 91 records · Page 5Linked to original sources
PubMed1984

Analysis of plasma lipids and apolipoproteins in insulin-dependent and noninsulin-dependent diabetics.

Plasma triglycerides, cholesterol, high-density lipoprotein (HDL) cholesterol, and apolipoproteins (apo) A-I, A-II, C-II, and C-III were determined and analyzed in 170 diabetic patients and 46 age-matched healthy normal subjects. The diabetics were separated into two groups: insulin-dependent diabetes mellitus (IDDM, n = 78) and noninsulin-dependent diabetes mellitus (NIDDM, n = 92). Significantly increased triglycerides, low HDL cholesterol, and normal cholesterol levels were found in the diabetics. The lipid profiles were similar in the IDDM and NIDDM groups. Plasma apo A-I, but not apo A-II, was low in both groups of diabetics. However, only in the IDDM subjects was there a statistically significant decrease in apo A-I when compared to normal subjects. The decreased apo A-I level negatively correlated with plasma triglycerides. Apo C-II and apo C-III were slightly increased in the diabetics compared to normal subjects. Apo C-II and apo C-III levels significantly correlated with plasma triglycerides (apo C-II, r = 0.70, P less than 0.0001; apo C-III, r = 0.71, P less than 0.0001). Only apo C-II correlated with total cholesterol. Thirty-eight to forty-two percent of the IDDM and NIDDM subjects had a clinical diagnosis of coronary artery disease (CAD) and/or peripheral arteriovascular disease (PAD). In the IDDM subjects, but not in the NIDDM subjects the incidence of CAD and/or PAD was associated with the decreased apo A-I levels as evaluated by a univariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein A-I↗
PubMed1984

Primary hypercholesterolemia: effect of treatment on serum lipids, lipoprotein fractions, cholesterol absorption, sterol balance, and platelet aggregation.

The nonabsorbable bile acid sequestrant resin, colestipol, was administered to 16 patients with primary hypercholesterolemia, and its effect on serum lipids, lipoprotein fractions, and circulating platelet aggregate ratio and platelet aggregation in response to adenosine diphosphate (ADP) was compared with that of sitosterol. Cholesterol absorption and sterol balance studies were done in four of the subjects during the following treatment periods: diet alone, colestipol, and sitosterol. Total serum cholesterol was significantly reduced by colestipol but only slightly decreased by sitosterol. Combination treatment with colestipol and sitosterol was associated with a smaller decrease in serum cholesterol than was demonstrated with colestipol alone. Serum triglycerides tended to increase during colestipol therapy (this increase was not clinically significant) but showed a minimal nonsignificant decrease with sitosterol treatment. Colestipol decreased cholesterol absorption, whereas sitosterol slightly increased it. Fecal sterol excretion was increased with colestipol treatment but was minimally affected by administration of sitosterol. Low-density lipoprotein and high-density lipoprotein cholesterol significantly decreased with colestipol treatment. The circulating platelet aggregate ratio was significantly lower in the group of patients with hypercholesterolemia who received colestipol initially than in control subjects, but platelet aggregation in response to ADP was not significantly different between these two groups. No significant change in platelet aggregation was noted during colestipol or sitosterol treatment despite a significant decrease in total serum cholesterol with colestipol therapy, a suggestion that the platelet and lipid abnormalities are not interrelated.

Adenosine Diphosphate↗
PubMed1984

Acute effects of a glucose load on plasma apolipoproteins A-I, A-II, C-II, and C-III in normal and non-insulin-dependent diabetic men.

Changes in plasma levels of apolipoproteins A-I, A-II, C-II, and C-III, cholesterol, triglycerides, glucose, and insulin were studied after administration of a glucose load in six normal subjects and five patients with non-insulin-dependent diabetes mellitus. The main finding of our study was the significantly increased responses of total triglycerides and apolipoproteins C-II and C-III from the baseline values in the normal subjects but not in the diabetic group. High-density lipoprotein cholesterol levels at baseline and after glucose loading were significantly lower in diabetic than in normal subjects. As expected, abnormal glucose tolerance and hyperinsulinemia were observed in the diabetic subjects after the glucose loading. The peak glucose and insulin levels and their decline after the glucose loading were delayed in the diabetic patients. The glucose load did not significantly alter total plasma cholesterol, high-density lipoprotein cholesterol, and apolipoprotein A-I and A-II concentrations in normal and diabetic subjects. The apparent blunted response of total triglycerides and apolipoproteins C-II and C-III in the diabetic subjects may be related to maximal stimulation of synthesis of triglycerides and apolipoproteins C-II and C-III by the hyperglycemia and hyperinsulinemia (or both) present in these patients.

Administration, Oral↗
PubMed1984

Detection of genetic heterogeneity among pedigrees through complex segregation analysis: an application to hypercholesterolemia.

Several methods for investigating genetic heterogeneity for extreme levels of a quantitative trait with hypothesized multiple genetic etiologies require a priori stratification of families and/or identification of distinct phenotypes among affected individuals. We present a statistical approach for detecting genetic heterogeneity that does not rely on either a priori stratification or discrete disease phenotypes. Complex segregation analysis was applied to total serum cholesterol measurements in 709 relatives of 98 healthy index cases selected from 3,666 school children surveyed for lipid levels in Rochester, Minnesota. Thirty-three of the index cases and 109 relatives had hypercholesterolemia (cholesterol levels greater than the 95th percentile for their age and sex). Through application of the mixed genetic model and then estimation of conditional probabilities for having the mutant allele at the major locus, genetic heterogeneity for hypercholesterolemia was indicated. In three of 70 pedigrees with one or more hypercholesterolemics, there is strong evidence for segregation at a major locus. In the remaining pedigrees, only polygene variation and/or environmental variation are associated with cholesterol variability. Grandparents in the three pedigrees that were segregating at the major locus had the highest rates of death due to coronary heart disease. This study establishes that the mixed model has the potential to identify pedigrees with different genetic etiologies for variability in quantitative traits.

Adult↗
PubMed1983

Apolipoprotein A-I as a marker of angiographically assessed coronary-artery disease.

This study was designed to determine whether the plasma level of apolipoprotein A-I is a better discriminator of angiographically documented coronary-artery disease than the level of high-density-lipoprotein (HDL) cholesterol in male subjects. The level of plasma apolipoprotein A-I in 83 patients with coronary-artery disease was 96.7 +/- 4.2 mg per deciliter (mean +/- S.E.M.), which was significantly lower (P less than 0.0001) than the level in 25 patients without coronary-artery disease (146.9 +/- 2.1 mg per deciliter). The levels of HDL cholesterol were also lower (P less than 0.0001) in patients with coronary-artery disease (31.9 +/- 1.5 mg per deciliter) than in those without it (45.9 +/- 2.3 mg per deciliter). A stepwise discriminant analysis, however, indicated the superiority of apolipoprotein A-I over HDL cholesterol in detecting coronary-artery disease. Furthermore, a linear discriminant analysis suggested that although HDL cholesterol by itself was a discriminator of coronary-artery disease, it did not provide a substantial increase in discriminatory value over that provided by apolipoprotein A-I; in contrast, apolipoprotein A-I levels added discriminatory value to the information obtained by measuring HDL cholesterol alone. We conclude that apolipoprotein A-I by itself is more useful than HDL cholesterol for identifying patients with coronary-artery disease.

Analysis of Variance↗
PubMed1983

Total cholesterol and lipoproteins in school children: prediction of coronary heart disease in adult relatives.

The distribution of risk factors and the prevalence of coronary heart disease (CHD) were studied in 850 first- and second-degree relatives of 98 healthy index cases selected from 3666 school children surveyed for lipid levels in Rochester, Minnesota. Three groups of families were based on an index child's total plasma cholesterol level: 18 families with a child in less than the fifth percentile (low-cholesterol group), 47 with a child in the fifth to ninety-fifth percentiles (middle-cholesterol group) and 33 with a child in greater than the ninety-fifth percentile (high-cholesterol group). The children's cholesterol levels clustered with those of their relatives; mortality due to CHD before age 65 was increased by 2.5 times in grandfathers of index cases in the high-cholesterol group compared with those of the middle-cholesterol group (p less than 0.016). The prevalence of CHD in all the grandfathers was associated with an index child's total cholesterol, more strongly associated with an index child's low-density lipoprotein cholesterol level and most strongly associated with an index child's high-density lipoprotein cholesterol level as a fraction of total cholesterol. This study establishes that childhood lipid and lipoprotein levels from a single cross-sectional survey identify families at elevated risk for CHD.

Adolescent↗
PubMed1983

Monoclonal antibodies to human plasma low-density lipoproteins. I. Enhanced binding of 125I-labeled low-density lipoproteins by combined use of two monoclonal antibodies.

Four monoclonal antibodies (IgG2b) to human plasma low-density lipoproteins (LDL) have been characterized. The binding affinities of each monoclonal antibody to 125I-labeled LDL were moderately high, ranging from 10(8) to 10(10) L/mol at 4 degrees C, but were reduced by at least 50-70% at 37 degrees C. The maximum binding of each monoclonal antibody was unique, ranging from 20 to 95% of total 125I-labeled LDL, suggesting that LDL particles were immunochemically heterogeneous. One antibody, LP-34, had both high and low binding affinities to LDL. Another, LP-47, exhibited high affinity for isolated LDL, yet reacted poorly with native LDL in plasma, indicating that the conformation of isolated LDL differs from that of native LDL in plasma. Unlike polyclonal serum antibodies, a mixture of four monoclonal antibodies failed to precipitate LDL, but did show a drastic increase in binding to LDL. We found that only two of our monoclonal antibodies were necessary for such synergistic enhancement. We propose that one of the monoclonal antibodies may serve as a catalytic reagent, and discuss the clinical significance of this finding.

Antibodies, Monoclonal↗
PubMed1982

Cholesterol excretion studies in familial hypercholesterolemic children and their normolipidemic siblings.

Twenty children ages 3 to 17 yr, eight with normal lipids and 12 with familial hypercholesterolemia were studied on a metabolic unit for 14 days to evaluate fecal bile acid and fecal neutral sterol excretion. The diet contained a moderately low cholesterol content, 180 to 200 mg/day. Stools were collected in three separate, 3-day pools. Fecal bile acids and fecal neutral sterols were measured using two stool markers and thin-layer, and gas-liquid chromatography techniques. Fecal neutral sterol and fecal bile acid excretion were the same for normal and familial hypercholesterolemic children on a mg/kg basis. Fecal neutral sterols in familial hypercholesterolemic children decreased with age, p less than 0.001; fecal bile acid excretion also appeared to decrease with age, but less significantly, p less than 0.07. Although the familial hypercholesterolemic children have significantly increased plasma and potentially elevated tissue or total body cholesterol, the excretion of fecal bile acids and fecal neutral sterols did not differ between familial hypercholesterolemic and normal children.

Adolescent↗
PubMed1981

Immunochemistry of human plasma apolipoprotein C-II as studied by radioimmunoassay.

The immunoreactivity of human plasma apolipoprotein C-II was investigated using a specific radioimmunoassay. In whole plasma, the mean value quantitated was 2.21 +/- 0.415 mg/dl, while in delipidated plasma, a mean value of 3.84 +/- 1.186 mg/dl was obtained, suggesting that the antigenic sites of the apolipoprotein were not fully detected in unmodified plasma by our antibody preparation. Two detergents, Tween-20 and Triton X-100, were studied to determine if they could enhance the immunoreactivity of apolipoprotein C-II in whole plasma. At concentrations of 0.012-0.06%, Tween-20 markedly increased the immunoreactivity of whole plasma, but not of delipidated plasma, indicating that antigenic sites of plasma apolipoprotein C-II has been exposed by Tween-20. In contrast, Triton X-100 had no effect on the immunoreactivity of whole plasma apolipoprotein C-II. A radioimmunoassay conducted in the presence of 0.06% Tween-20, resulted in a mean value in whole plasma (3.39 +/- 1.11 mg/dl) that was not significantly different from that obtained when the assay was done on delipidated samples. The immunoreactivity of VLDL apolipoprotein C-II was also drastically enhanced following lipolysis by bovine milk lipoprotein lipase, supporting the hypothesis that antigenic sites are masked by the lipids. Finally, the mechanism responsible for the effect of Tween-20 on apolipoprotein C-II immunoreactivity was investigated. The results obtained from circular dichroism and ultracentrifugation suggest that the detergent may dissociate the apolipoprotein from lipoprotein particles, thus fully exposing the antigenic sites for reaction with antibodies.

Adult↗
PubMed1981

Regional aortic differences in atherosclerosis-susceptibility: changes in prostaglandin biosynthesis and cholesterol accumulation in response to desoxycorticosterone (DOCA)-salt induced hypertension.

In spontaneously atherosclerosis-susceptible White Carneau pigeons, intimal cushions that appear at birth near the coeliac branch of aorta do not progress into atherosclerotic lesions. However, the area across from the intimal cushion (so called 'lesion area') a) accumulates cholesteryl esters b) synthesizes more PGE2 and c) eventually develops into complicated atherosclerotic plaques. When DOCA-salt hypertension is induced in the pigeons, the 'initimal cushion' area displays a) accumulation of increasing amounts of cholesteryl esters and b) increase in the synthesis of all prostaglandins (particularly PGE2) from C14-arachidonic acid and c) approaches similarity to the 'lesion area' in the magnitude of these changes. These results suggest that under the influence of a risk factor, the 'intimal cushion' can acquire biochemical properties of the atherogenic areas of the aorta.

Animals↗
PubMed1981

Postprandial exchange of apolipoprotein C-III between plasma lipoproteins.

Three healthy male subjects were given a high fat meal after fasting for 12 h. Blood samples were drawn at hourly intervals over 6 h. The plasma triglyceride levels reached peak values within 3 to 6 h postprandially. Plasma cholesterol concentration, however, remained constant in the three subjects as well as in a fasting normal subject. Apolipoprotein C-III (apoC-III), a major apoprotein in triglyceride-rich lipoprotein particles and known to be exchangeable between plasma high density lipoproteins (HDL) and triglyceride-rich particles, was studied in regard to its net transfer between lipoproteins during meal absorption and postabsorptive lipolysis. ApoC-III levels in total plasma as quantitated by radioimmunoassay were stable regardless of the increase of plasma triglycerides. When triglyceride levels increased after a meal, apoC-III in the d. less than 1.063 lipoprotein fraction increased concomitantly, while apoC-III in HDL decreased. The converse was observed during lipolysis as plasma triglycerides fell. In any case, apoC-III levels in d. less than 1.063 lipoproteins were positively correlated with plasma triglycerides (r = 0.82, p less than 0.01) after the meal. The finding suggests that the apoC-III concentrations in HDL are very dynamic in vivo. ApoC-III can transfer from HDL to triglyceride-rich particles during meal absorption and can transfer from triglyceride-rich particles to HDL during postabsorptive lipolysis.

Absorption↗
PubMed1981

Association of risk factor variables and coronary artery disease documented with angiography.

Stepwise linear discrimination was used to analyze risk factors in 431 consecutive patients who underwent coronary angiography to determine which variables were most closely associated with coronary artery disease. Twenty-one risk factors were considered: total plasma cholesterol and triglycerides; the cholesterol and triglyceride content of high-density lipoproteins (HDL), low-density lipoproteins (LDL) and very low density lipoproteins (VLDL); and the percentage of total cholesterol and triglycerides in each fraction. Age, smoking history, family history, hypertension, diabetes mellitus and relative weight were also considered. Coronary artery disease was assessed using three standard grading scores. There were significant differences in risk factors between males and females. In males, LDL cholesterol and age were selected by multivariate analysis. In females, the ratio of HDL cholesterol to total cholesterol, as well as relative weight, family history, age and smoking were selected. The discriminating value of HDL cholesterol as the percentage of total cholesterol was significantly greater than that of HDL cholesterol itself. Despite highly significant associations between risk factors and the presence of coronary artery disease, the discrimination did not provide sufficient separation of the groups to give results that are useful diagnostically in individual patients.

Adult↗
PubMed1981

Heterozygous defects in alpha 1-antitrypsin and low-density lipoprotein receptor. Simultaneous occurrence in a pediatric patient.

alpha 1-Antitrypsin is a serum protein protease inhibitor. The homozygous deficiency state for alpha 1-antitrypsin is associated with the development of chronic obstructive lung disease and liver cirrhosis. Familial hypercholesterolemia is a genetic defect in which the nonhepatic tissues of affected persons are partially or completely deficient in cellular receptors for low-density lipoproteins, the major plasma cholesterol transport protein. Homozygotes and heterozygotes for familial hypercholesterolemia experience premature coronary artery disease. We have identified a young patient who manifested heterozygous deficiencies for both of these gene products. The occurrence of these defects in tandem has not been previously reported.

Child↗
PubMed1980

Tween-20 increases the immunoreactivity of apolipoprotein A-I in plasma.

Tween-20 (polyoxyethylene 20), a trademark for a sorbitan polyoxyalkalene derivative is used as an emulsifier and detergent. In present studies, we report that Tween-20 is able to reduce the nonspecific binding of radiolabeled apolipoprotein A-I to test tubes. It also enhances the specific binding of 125I-labeled apolipoprotein A-I to anti-apolipoprotein A-I antibodies. Maximal enhancement was achieved at a Tween-20 concentration greater than 0.08%. The results were confirmed by using two different antisera raised in rabbits and goats. Since the immunoreactivity of apolipoprotein A-I in plasma cannot be fully detected by a conventional radioimmunoassay procedure, we have, therefore, studied the effect of Tween-20 on the immunoreactivity of apolipoprotein A-I in plasma. As determined by inhibition radioimmunoassay, we found that Tween-20 drastically increased the immunoreactivity of apolipoprotein A-I using both rabbit and goat antisera. The maximal reactivity was achieved at a Tween-20 concentration of 0.32%. However, Tween-20 did not enhance the immunoreactivity of delipidated plasma. Thus, the results indicate that the plasma lipids may hamper apolipoprotein A-I immunoreactivity and suggest that the nonionic detergent, Tween-20, somehow interacted with HDL lipids or the apolipoproteins and then facilitated the reaction of antigenic reactive site(s) of apolipoprotein A-I with their antibodies.

Antibody Specificity↗
PubMed1980

Physical, chemical, and immunochemical studies of apolipoprotein A-I from pigeon plasma high density lipoproteins.

Pigeon plasma high density lipoproteins (HDL) were isolated by ultracentrifugation between the densities of 1.063 and 1.21 g/ml. Gel filtration of delipidated HDL in 5 M guanidine-HCl on Sephadex G-150 yielded a major fraction which eluted at the same position as human apolipoprotein A-I isolated from HDL. In SDS-gel electrophoresis, the isolated apolipoprotein co-migrated with human apolipoprotein A-I with a molecular weight of approx. 28 000. The amino acid composition was similar to the apolipoprotein A-I isolated from human and hen plasma. The isolated apolipoprotein from pigeon plasma had therefore been designated as apolipoprotein A-I. As judged by circular dichroism (CD), the apolipoprotein A-I displayed a maximum mean residue ellipticity of approx. -3 000 at 222 nm while at concentrations greater than 0.2 mg/ml. Calculations of alpha-helicial content gave values of 85%. Lowering the concentration of apolipoprotein A-I was found to concomitantly decrease the ellipticity (absolute value) suggesting that there was some conformational change when the apolipoprotein A-I concentration varied. The isolated pigeon apolipoprotein A-I was found bound to the phospholipid (dimyristoyl phosphatidylcholine) and there was no significant conformational change upon lipid binding as judged by CD. Under the same experimental conditions, human apolipoprotein A-I exhibited a drastic conformational change by increasing its helicity in the presence of phospholipid. The helical content of human apolipoprotein A-I was increased from 48 to 85%. This finding suggests that the apolipoprotein may not necessarily increase its helical content during lipid binding. Moreover, immunochemical studies showed that rabbit antiserum prepared against pigeon apolipoprotein A-I could partially react with human apolipoprotein A-I determined by quantitative radioimmunoassay.

Amino Acid Sequence↗