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Biomedical subjects

C L Malmendier

Publications and source records attributed to C L Malmendier.

At least 55 records · Page 3Linked to original sources

Plasma levels of apolipoproteins A-I, A-II and B in alcoholism. Relation to the degree of histological liver damage, and to liver function tests.

In 101 alcoholic patients, plasma apolipoproteins A-I, A-II and B, and lipids were studied in relation to liver function tests, albumin and bilirubin. As compared with controls, the entire population revealed a slight increase in triglycerides, transaminases and bilirubin, and a marked increase in gamma glutamyl transferase. The population was divided into 3 groups according to histological liver microscopy: no lesion, steatosis and cirrhosis. In group 1, apo A-I, A-II and HDL-C were significantly increased. In steatosis, apo A-I, apo A-II and HDL-C had almost normal levels. In cirrhosis, the 3 parameters were significantly decreased, but the apo A-I/apo A-II ratio was increased in relation to the predominant decrease in apo A-II. Liver enzymes were not discriminative, not even gamma GT, which was increased in all 3 groups. Apolipoprotein B, total cholesterol and LDL-cholesterol were insensitive to the degree of hepatic involvement, but a low apo A-I/B ratio might be indicative of a cardiovascular risk. It is suggested that apoproteins and their ratios be used as new markers for the degree of alcoholic intoxication and the risk of cardiovascular complications.

Adult↗

Apoprotein S, a family of human serum lipoprotein polypeptides.

Glucose infusions given to neurological and postsurgical patients in the absence of oral feeding were found to increase the amount of new polypeptides in high density lipoproteins from 3 to 40% of total proteins as compared to 0.1% in normal subjects fed a regular diet. This increase was observed in HDL2 as well as in HDL3 and even in VLDL. Eight polymorphic forms were detected by chromatography, polyacrylamide gel electrophoresis and isoelectric focusing. The partial amino acid sequence of one of these forms is given: the first 26 NH2-terminal residues are identical to the amphipathic helical segment of SAA protein, theoretically responsible for the lipid binding. The role of glucose as the major factor involved in the production of these apoproteins is discussed.

Adult↗

Effect of sialic acid removal on human low density lipoprotein catabolism in vivo.

This study was undertaken to determine whether sialic acid removal alters the catabolism of low density lipoprotein in humans. Human low density lipoproteins labeled in vitro with 125I were incubated in the presence (termed desialylated) or absence (sialylated) of neuraminidase. The treatment with neuraminidase from Clostridium perfringens removed 90% of the sialic acid residues which did not change the chemical composition of the lipoproteins. Sialylated or desialylated LDL were injected intravenously into normal human subjects. The mathematical analysis of the plasma radioactivity decay curves (followed for 220 h) of desialylated low density lipoproteins, when compared with sialylated LDL, showed a shorter mean transit time (51 h vs 60 h), a 52% faster metabolic catabolic rate and an increased volume of distribution. The data are consistent with a proposed metabolism of low density lipoproteins: in humans, desialylation appears to accelerate the first step of the low density lipoprotein conversion but not to alter its final catabolism.

Adult↗

A new cryopathic syndrome.

One case of a syndrome simulating a systemic disease is reported. An HLA-B, patient presented with apparent toxoplasmosis, retinal vein occlusion, autoantibodies against cephalin, contact factors and lipoproteins, immune complexes, rheumatoid factor, and cryoprecipitate. A representation of the immunological mechanisms involved is proposed.

Antigen-Antibody Complex↗

Separation and partial characterization of new apoproteins from human plasma high density lipoproteins.

In four patients receiving parenteral fluids, human plasma high density lipoproteins were obtained by sequential ultracentrifugation and delipidated. Apoproteins were resolved by gel filtration on Sephadex G-200, DEAE-cellulose chromatography, and polyacrylamide gel electrophoresis. Sephadex-Fraction V was unusually large (11--33% compared to 3--7% in normal subjects) and was found to contain seven new apoprotein components of an apparent molecular weight (by SDS gel electrophoresis) between 8000 and 11 000. Amino acid analysis showed that all these peptides had a high glycine and arginine content and a very low content of threonine and valine. Isoelectric focusing gave isoelectric points ranging from 5.00 to 8.00. In two patients injected with L-[1-17C]-leucine, incorporation of radioactivity into these peptides gave specific activities of the same order of magnitude as apo C-II and apo C-III. IT may be postulated that these peptides increased significantly when proteins are deficient in the diet or have low levels in plasma. The structural and functional significance of these peptides remains to be determined.

Adult↗

A long-term study of the efficacy of oxandrolone in hyperlipoproteinemias.

Oxandrolone, an anabolic steroid, significantly reduced serum triglycerides in type III, IV, and V hyperlipoproteinemia, with a concomitant decrease in pre-beta lipoproteins. Its slightly enhancing effect on serum cholesterol and absolute increase in beta lipoproteins might eventually discourage its administration in type II patients. Alpha lipoproteins always remained at low levels. In addition to its hypotriglyceridemic action,, oxandrolone induced a slight reduction in uric acid and alkaline phosphatases. Untoward side effects were not observed even after prolonger therapy. Therefore, oxandrolone might deserve a place among the few available triglyceride-reducing therapies.

Adolescent↗

Relationship between the carbohydrate content of apoproteins of VLDL, IDL, and LDL and the plasma level of these lipoproteins in man. Short dietary effect.

A 1,500 Cal test meal was used to study in man the apoprotein B-carbohydrate content and composition of VLDL, IDL and LDL in relation to the variation of plasma lipids and lipoproteins and the VLDL-apoprotein composition. Three essential facts emerge from the study: (1) the mirror image (inverse significant correlation) between VLDL-apo B plasma concentration and N-acetylglucosamine content of apo B; (2) a reduction in total carbohydate concentration of VLDL- and LDL-apo B, 2--4 h after the test meal and a trend to a reduction in the mannose content; (3) a significant correlation between sialic acid and apoprotein B concentration in plasma LDL during fasting. The effect of diet and subsequent fasting on carbohydrates of lipoproteins and the consequence of such changes on lipoprotein uptake are briefly discussed.

Apoproteins↗

Influence of lyophilized total pancreas on plasma lipids and on fat absorption in cystic fibrosis.

31 children with cystic fibrosis (CF) subdivided into three groups of age were studied before and after treatment with lyophilized pancreas and compared to 27 controls. CF was characterized by lower phospholipid, cholesterol and polyunsaturated fatty acid plasma concentrations and reduced coefficient of fat absorption. Treatment tended towards normalization of these values. With age polyunsaturated fatty acids increased in normals but not in CF. The significant correlations existing between fat absorption coefficient and polyunsaturated fatty acid percentage in neutral lipids of CF children suggests the use of the latter percentage as index of the stage of malabsorption.

Adolescent↗

Apoprotein profile of plasma and chylous ascites lipoproteins.

Plasma and chylous ascites lipoproteins were compared in a rare case of exudative enteropathy associated with stenosis of the thoracic duct. All ascites lipoproteins separated by ultracentrifugation showed a much higher triglyceride/protein ratio and a lower cholesterol ester content than their plasma counterparts. Polyarcylamide gel electrophoresis of apoproteins before and after fractionation on Sephadex G-200 essentially showed, compared to normal plasma, a reduction of apoprotein C in VLDL and HDL particularly obvious for apoCIII1 and CIII2. Ascites lipoproteins were characterized by an increased apoA content in chylomicrons, VLDL and LDL and a reduced percentage of apo CII and CIII1, mostly in chylomicrons, VLDL and HDL. The differences in composition between plasma and ascites might be explained by different origins for the various apoprotein subfractions. The transsudation of chyle into the abdominal cavity might divert some peptides of intestinal origin from their normal entry into the circulation.

Apoproteins↗