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Biomedical subjects

J C Buxtorf

Publications and source records attributed to J C Buxtorf.

At least 19 recordsLinked to original sources
PubMed1994

Familial xanthomatous hypercholesterolemia: abnormal exogenous lipid metabolism evidenced by the vitamin A test.

Familial xanthomatous hypercholesterolemia is a metabolic disorder associated with high LDL levels attributed to a familial defect in LDL receptor activity. We have previously shown that hyperlipoproteinemia of WHHL rabbits, considered to be a model for heritable hypercholesterolemia, was at least partly of exogenous origin. We have though studied retinyl palmitate (RP) levels 12 h after a standardized mixed meal as a simple test to detect abnormalities of intestinal-derived lipoprotein clearance in 22 familial hypercholesterolemic patients with xanthomatosis (13 of them treated by simvastatin, an HMGCoA reductase inhibitor, and 9 not treated), as compared to a control group (n = 12). Total and LDL cholesterol, plasma triglyceride and apo B levels were significantly higher in patients when compared to controls. Mean RP levels appeared higher in familial hypercholesterolemic patients, when compared to controls, with 6 among 22 patients showing clearly high vitamin A levels and 4 borderline values, whereas high triglyceride levels (> 2 g/l) were detected in only 1 patient. No patients within the group with high vitamin A levels showed an apo E2/E2 phenotype. Vitamin A levels correlated with plasma triglycerides in the whole group of subjects (r = 0.50, p < 0.05). No difference was observed in vitamin A distribution between treated and untreated hypercholesterolemic patients. Our results indicate that the clearance of RP-labeled intestinal lipoproteins is delayed in some xanthomatous familial hypercholesterolemic patients as compared with that of controls. These findings suggest that familial xanthomatous hypercholesterolemia may be heterogenous concerning physiopathological mechanisms inducing hyperlipidemia.

Adult↗
PubMed1991

[Determination of lipoprotein Lp(a). A semi-automatic immuno-turbidimetric method].

A sensitive, accurate, semiautomatic immunoturbidimetric assay for determining Lp(a) levels using a Hitachi 705 apparatus is described. A polyclonal antibody against anti-Lp(a) produced by Immuno-france is used. Studies proved that this test is reliable and that results are well correlated with those obtained by immunonephelometry.

Immunoassay↗
PubMed1988

Seasonal variations of serum lipids and apoproteins.

Seasonal variations of blood lipids, which must be considered when performing long-term studies, could be partially due to dietary changes. In the present study, serum lipid parameters were measured each month for 1 year in nuns living in a monastery, whose diet was perfectly regular and controlled. The serum lipid variations observed consisted mainly of an increase in total cholesterol, low-density lipoproteins and apolipoprotein B in autumn and spring and an increase in high-density lipoprotein cholesterol in winter, whereas apolipoproteins A-I and A-II showed a marked increase in summer and at the beginning of autumn. These variations were probably induced by factors directly related to seasonal rhythm and not to dietary factors or physical exercise. Lastly, the influence of sex hormones seems to be very minor, as postmenopausal women (one-third of the persons) had an identical variation in their lipid parameters, to that observed in the whole group.

Adult↗
PubMed1985

The hypolipidemic action of probucol. Drug transport and lipoprotein composition in type IIa hyperlipoproteinemia.

In this study Probucol transport and the effect of the drug on lipoprotein composition in 9 cases of type IIa hypercholesterolemia were investigated. Probucol lowered plasma cholesterol by 20%, without affecting triglycerides. HDL cholesterol was decreased and a slight reduction in LDL cholesterol was noted. This was due to a reduction in the number of circulating lipoprotein particles, without modification in the lipid/protein ratio, mainly cholesterol/protein ratio. Probucol was almost entirely removed by lipoproteins; 75% of the drug was found in LDL, the remainder being equally distributed in VLDL and HDL. There was no correlation between the serum Probucol level, or the amount of Probucol bound to lipoproteins, and the decrease in serum or lipoprotein cholesterol. However, there was a significant increase of the EC/TC (esterified cholesterol/total cholesterol) ratio in VLDL and LDL, but not in HDL.

Adult↗
PubMed1985

Quantitative determination of free cholesterol and cholesteryl esters in skin biopsies.

A new technique is described for the determination of cholesterol in skin biopsies which is sensitive, practical and reproducible. The determination of cutaneous cholesterol is of clinical interest, because of its correlation with the degree of atherosclerosis. There was no correlation found between the blood total cholesterol and total triglycerides, and cholesterol and triglycerides determined in the skin biopsies. Determinations were carried out on several normal subjects, 7 long-distance runners, 34 hyperlipidemic patients. There was a significant increase with age of total skin cholesterol in the normal subjects, the values obtained with the long-distance runners had a tendency to be somewhat lower. All the patients investigated had higher cholesterol values than the normal controls or the sportsmen. This technique can be used therefore as a diagnostic tool to detect pathologies of skin lipids, or of tissue lipid metabolism, as for example in normolipidemic patients presenting corneal arcus or xanthelasmas.

Adult↗
PubMed1982

Effects of probucol on the cholesterol content of skin in type II hyperlipoproteinemias.

500 mg of probucol were given twice a day for 6 months to 20 type II hyperlipoproteinemic patients, 14 men and 6 women, including 10 type IIb and 10 type IIa cases. Tendon xanthomas were present in 11 and xanthelasma in 4. Their mean blood cholesterol level was 435 +/- 100 mg/100 ml and triglycerides 210 +/- 138 mg/100 ml. A normal diet was maintained during the treatment period. Skin biopsies were made on the forearm, before and after the 6 month treatment. After lyophilization of the skin fragments, the free and esterified cholesterol contents were measured by gas chromatography after preparative thin layer chromatography on silica gel. The free and esterified cholesterol contents of the skin both appear to be significantly increased when the values found before treatment in these patients are compared with those of skin analysis in 10 normal controls: 2.25 to 1.58 micrograms/mg freeze-dried skin, p less than 0.001 for the esterified fraction. After 6 month probucol treatment the free cholesterol does not change significantly (2.25 to 2.16) and the esterified cholesterol increases (0.44 to 0.66, p less than 0.01). This effect is suggestive of an interaction of probucol with the synthesis and transport of cholesterol at the tissue level. It may be significant for the understanding of the effects of this drug and others on xanthelasma, tendon xanthomas, and atherosclerosis. In one of the cases studied here, the xanthelasma was greatly reduced during the treatment.

Cholesterol↗
PubMed1981

Study of free and esterified cholesterol in skin in atherogenic hyperlipidemias.

Free and esterified cholesterol in the skin were assayed by gas chromatography after thin layer histochromatographic separation. There were 20 controls of both sexes, 36 subjects with type lla hyperlipoproteinemia, 27 with type IIb hyperlipoproteinemia and 19 with type IV hyperlipoproteinemia. Esterified skin cholesterol levels were higher in women with the type of lla disorder and in subjects with tendinous xanthomas. The levels of esterified skin cholesterol in type II women is not correlated with free skin cholesterol or with total circulating cholesterol; all these parameters are correlated in men. Furthermore, skin cholesterol levels were determined in 15 type II subjects before and after a six month treatment with the anticholesterolemic probucol. Cholesterolemia decreased 10 per cent, free skin cholesterol decreased slightly and esterified skin cholesterol increased significantly, as did the esterified/total skin cholesterol ratio. These data suggest the existence of a relationship between low vascular risk and elevated levels of esterified skin cholesterol (or elevated esterified/total skin cholesterol ratio).

Adult↗
PubMed1981

[Immunoglobulins and hyperlipoproteinemias].

With the objective of detecting autoimmune hyperlipidemias (AIH) we looked for the immunoglobulins bound to the low-density lipoproteins (test Ig-Lp): in 50 normolipidemic subjects and, in 133 hyperlipoproteinemic patients: 43 of type IIa, 34 of type IIb, 36 of type IV and 20 of Type V. The Ig-Lp was negative in the 50 normolipidemic subjects. It was positive in 26 hyperlipoproteinemic cases, including; 5 of type IIA, 3 of type IIb, 7 of type IV and 11 of type V. These results were compared to those of a previous smaller study, which had not been randomized. The present work confirms the interest of such a test. Although it does not allow to ascertain that the tested hyperlipoproteinemias are AIH, it suggests that there is a specific relation between immunoglobulins and lipoproteins.

Humans↗
PubMed1981

[Free and esterified cholesterol of the skin in atherogenic hyperlipidemias].

Skin free and esterified cholesterol were assayed using gaseous chromatography following plaque histochromatography separation in 20 control, 36 patients with Type II a hyperlipoproteinemia, 27 with Type II b hyperlipoproteinemia and 19 with Type IV hyperlipoproteinemia. Skin esterified cholesterol was higher in females with Type II a hyperlipoproteinemia without or with xanthomatosis. But the skin esterified cholesterol level was not correlated with skin free cholesterol nor with blood total cholesterol levels, while in males these parameters were well correlated. On the other hand skin cholesterol was assayed in 15 patients with Type II hypercholesterolemia before and after a 6-month treatment with Probucol: there was 10p. 100 reduction of cholesterol level, and a weak decrease in skin free-cholesterol; in contrast, skin esterified cholesterol increased significantly as well as the skin esterified cholesterol/skin total cholesterol ratio (EC/TC). These data suggest a connection between weak vascular risk and skin esterified cholesterol high level (or high EC/TC in skin).

Aged↗
PubMed1980

[Effects of probucol on skin cholesterol concentrations in patients with type II hyperlipoproteineamia (author's transl)].

Twenty patients (14 male and 6 female) with hyperlipoproteineamia (type IIa in 10 and type IIb in 10) were given probucol 500 mg b.d. during 6 months. Eleven patients had xanthoma tendinosum and 4 had xanthelasma. The mean plasma cholesterol and plasma triglyceride levels were 435 +/- 100 mg/dl and 210 +/- 138 mg/dl respectively. Normal diet was continued throughout. Skin biopsies were performed on the forearm before and after treatment. The skin fragments were freeze-dried, and free (FCh) and esterified (ECh) cholesterol concentrations were measured by gas chromatography after preliminary thin layer chromatography on silica gel. FCh and ECh were found to be significantly increased before treatment when compared with skin concentrations in 10 control subjects; FCh ranged from 2.25 to 1.58 microgram/mg (p < 0.001) and ECh from 0.44 to 0.16 microgram/mg of dry tissue (p < 0.001). After 6 months' treatment with probucol, there was no significant change in FCh (2.25 to 2.16 microgram/mg), but a significant rise was observed in ECh (0.44 to 0.66 microgram/mg; p < 0.01). This effect suggests that probucol interferes with cholesterol synthesis and transport in human tissues, which might help to comprehend the action of this and other drugs on xanthelasma, xanthoma tendinosum and atherosclerosis. In one of the patients, a xanthelasma was considerably reduced in size following probucol treatment.

Adult↗
PubMed1980

A quick and simple method for serum HDL determination permitting establishment of an atherogenic index.

The present report describes a simple method of differential flocculation for the various lipoproteins. The method, derived from Seidel, allows estimation of serum HDL (high density lipoproteins) as well as determination of the HDL divided by LDL + VLDL ratio. Using Technicon apparatus, total serum lipoprotein flocculation was measured with a dextran solution, and flocculation of LDL + VLDL (low and very low density lipoproteins) was determined with a heparinate solution. The difference between these two measurements reflected the serum HDL level. Results for several verification tests confirmed the method's reliability and showed it to correlate satisfactorily with other quantity determination techniques.

Arteriosclerosis↗
PubMed1979

[Type V hyperlipemia. 54 cases (author's transl)].

Type V hyperlipemia is not very common. The series of 54 cases descrubed here is the largest reported to date. Our observations were recorded when lipidograms showed the presence of chylomicrons and a large pre-beta-lipoprotein spot in the serum of fasting subjects. Type V hyperlipemia was often combined with other metabolic syndromes such as diabetes, hyperuricemia or gout, or obesity. Chronic alcoholism was also noted in half our subjects, in whom hyperlipemia quickly regressed after alcohol consumption ceased. Ischemic arterial complications, chiefly coronary, were found in one third of our cases, and the vascular risks accompanying this type of hyperlipemia rose considerably in patients with high blood pressure. Various type of treatment were administered, but all subjects were put on a special diet, comprising either the elimination of alcoholic drinks only, or, in addition to this, reduced carbohydrate or calorie intake. As a rule, these measures resulted in a distinct regression of lipid anomalies. Clofibrate or derivatives proved effective in cases where hyperlipemia failed to respond to dietary measures.

Adolescent↗
PubMed1978

[Lipid particles agglutinated in hyperlipidemias with opalescent sera (author's transl)].

During the five last years, we observed under the microscope all the hyperlipidemic sera received in our laboratory, to search a lipid particle agglutination. We have retained 24 sera with obvious agglutination (9 types V, 9 types IV and 6 types IIb), the lipidemia of which was compared, type to type, to 56 control sera (16 types V, 16 types IV and 24 types IIb), in which no agglutination has been found. We observed significant differences in the means of cholesterol (CT) triglycerids (TG), vitamin A (VA) and CT/TG, VA/TG and VA/CT ratios, comparing agglutinated and control sera. These differences suggest that the agglutination phenomenon is in relation with the nature of the lipid particles present in the hyperlipidemic sera, which could be "chylomicron remnants" in type V hyperlipidemias, and other forms of "remnants" in type IV and IIb hyperlipidemias. These "remnants" could result from a blockade of lipolysis. This blockade of lipolysis in the agglutinated sera might be related to what is known about the authentificated autoimmune hyperlipidemia (AIH). Thus we can suppose that hyperlipidemias with obvious serum lipid particle agglutination are autoimmune hyperlipidemias.

Agglutination↗
PubMed1977

[Residual dyslipoproteinemias after ethanol-weaning in alcoholic hyperlipidemic patients (author's transl)].

Twenty-two hyperlipidemic and long-term alcoholic patients were chosen as subjects with a chronic alcohol-dependent hyperlipoproteinemia, since their lipidemia was getting normal after they stopped alochol ingestion. After ethanol-weaning of these subjects, we found quantitative abnormalities of lipidemia (hypocholesterolemia in 5 cases among 22) and qualitative abnormal electrophoretic patterns in all cases: There is always a VLDL stain, a reduction of the LDL and VLDL migration. These facts suggest that exists in these patients a constant abnormality either in the enzymatic, or in the lipoprotein structures, which is induced or revealed by alcohol ingestion.20

Alcoholism↗