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Biomedical subjects

C L Malmendier

Publications and source records attributed to C L Malmendier.

At least 37 records · Page 2Linked to original sources
PubMed1988

Modifications of plasma lipids, lipoproteins and apolipoproteins in advanced cancer patients treated with recombinant interleukin-2 and autologous lymphokine-activated killer cells.

Intravenous injection of recombinant interleukin-2 (r-Met-hu-IL-2(Ala-125] and LAK cells induced dramatic changes of lipoproteins in 12 patients with advanced cancer. After r-IL-2 injection (1) total cholesterol was reduced by 47% as a mean, LDL-cholesterol by 62%, HDL-cholesterol by 77%; (2) the triglyceride/cholesterol ratio was greatly increased (352%); (3) apolipoproteins B, A-I and A-II showed a mean reduction of 26%, 55% and 51%, respectively; and (4) very low density lipoproteins relatively increased, and HDL were separated into two definite fractions (I and II). LAK cell administration accentuated all the above effects and in most patients, HDL-fraction I almost completely disappeared. An action on hepatic synthesis of acute phase proteins is pointed out by the increase in C-reactive protein and apolipoprotein S concentrations contrasting with an unexpected reduction of fibrinogen. Surprisingly the drastic changes caused by treatment were quickly and completely reversible.

Acute-Phase Proteins↗
PubMed1988

Metabolism of apolipoprotein C-III in normolipemic human subjects.

Radioiodinated apolipoprotein C-III labeled either by the iodine monochloride procedure or by the Bolton-Hunter reagent were incubated in vitro with normal HDL. The labeled HDL-apo C-III, after ultracentrifugation and dialysis, was injected intravenously in 8 normolipidemic subjects. The label was followed in VLDL, IDL + LDL, HDL, d = 1.225 g/ml infranate as well as in total plasma and urine for the first time over a period of 2 weeks. Apolipoprotein C-III distributes readily between the different lipoprotein classes, only a small amount being present in the non-lipoprotein fraction. The percent distribution of apo C-III radioactivity and mass was found similar in VLDL, IDL and HDL using 3 different separation methods. Residence time in the whole system was 2.45 +/- 0.33 days. Fractional catabolic rates calculated from the urine/plasma radioactivity ratios or from the plasma curve were 0.731 +/- 0.096 and 0.767 +/- 0.125 pools/day. Synthetic rate was 2.28 +/- 0.32 mg/day/kg. The parameters seem not affected by the labeling procedure. The shapes of the plasma curve and of the urine/plasma ratio curve suggest a kinetic heterogeneity in the metabolism of apo C-III-containing particles.

Adult↗
PubMed1988

Proposed folding pattern for apolipoprotein A-II based on a structural analogy with uteroglobin.

The tertiary structure observed in the crystalline state for uteroglobin, a small steroid binding protein, is used as a template to build an approximated model for apolipoprotein A-II. The presence of four proline residues and four hydrophobic clusters located at similar positions in apolipoprotein A-II and uteroglobin is taken as the major source of stability in such tertiary structures. A brief description of plausible specific binding sites appearing on the model of apolipoprotein A-II is given. It is suggested that the internal cavity and the four surface pockets observed for uteroglobin and postulated for apolipoprotein A-II might be used to insure specific binding of triglycerides, phospholipids, or cholesterol.

Animals↗
PubMed1987

The effect of combined fenofibrate and cholestyramine therapy on low-density lipoprotein kinetics in familial hypercholesterolemia patients.

The effects of combined drug treatment (fenofibrate and cholestyramine) have been investigated in vivo by simultaneously determining total and receptor-independent LDL catabolism with 125I-labelled LDL and 131I-labelled LDL coupled with cyclohexanedione. Receptor-mediated catabolism of LDL determined as the difference between the turnover of 125I and 131I, was found to be reduced in heterozygotes with familial hypercholesterolemia. Treatment with combined fenofibrate and cholestyramine markedly stimulated both receptor-mediated (by more than 2-fold) and receptor-independent catabolism. LDL-Apo B and LDL-cholesterol levels were reduced by 38% and 36%, respectively. The combined treatment also reduced the absolute synthetic rate of LDL-Apo B (by 9%). The mechanisms responsible for these kinetic effects are discussed.

Adult↗
PubMed1987

Comparison of different sandwich enzyme immunoassays for the quantitation of human apolipoproteins A-I and A-II.

Variants of a non-competitive enzyme immunoassay for human apolipoproteins A-I and A-II are described. The method developed is highly sensitive and highly specific. There is a good correlation between the reference technique (electroimmunoassay) and both apolipoprotein A-I and A-II assays (r=0.92). For the apolipoprotein A-I assay, seven simple treatments were studied. Two of these treatments (plasma plus Tween 20 and serum plus apo A-II) greatly increased the precision and the accuracy of the results. For the apo A-II measurement, no treatment of the samples is necessary, but plasma should be preferentially used rather than serum.

Apolipoprotein A-I↗
PubMed1987

In vivo metabolism of apolipoprotein S in humans. Comparison with apolipoprotein A-I metabolism.

125I-labelled apolipoprotein (Apo) S and 131I-labelled apolipoprotein A-I were injected i.v. into healthy volunteers. Blood samples and daily urine collections were drawn periodically for 15 days. Ninety-eight percent of 131I radioactivity and greater than 95% of 125I radioactivity were found in HDL after Superose gel chromatography of plasma. About 10% of each radioactivity was recovered in the d 1.250 infranate after one ultracentrifugation. Affinity chromatography on monoclonal anti-Apo A-I Sepharose column separates two lipoprotein particles containing Apo S, one retained with Apo A-I (42.5%) and the other eluting without Apo A-I (57.5%). Kinetic parameters were calculated according to exponential curve fitting. Mean transit time was about 7.0 days for both Apo A-I and Apo S. FCR of Apo S was 50% higher than FCR of Apo A-I. Synthetic rate of Apo S was about 150 times smaller than for Apo A-I. As heterogeneity of HDL-S was suggested by both the results of affinity chromatography and the urinary data, a compartmental model was built which fitted adequately all data. Part of the model is common to HDL-A-I and HDL-S.

Adult↗
PubMed1986

Metabolism of apolipoprotein C-I in normolipoproteinemic human subjects.

Labeling of apolipoprotein C-I by the Bolton and Hunter reagent allowed a study of the kinetics of this peptide in normolipidemic human volunteers. After its intravenous injection the appearance of radioactivity of the labeled apoprotein was followed in plasma, lipoprotein fractions, and urine for 15 days. Apolipoprotein C-I was quickly associated with HDL and to a smaller extent with VLDL in in vitro and in vivo incubation. Kinetic parameters of apolipoprotein C-I were compared with those of apo A-I. Fractional catabolic rates are respectively 0.422 +/- 0.044 vs 0.240 +/- 0.003 pools/day, residence times through the whole system 3.24 +/- 0.27 vs 6.31 +/- 0.27 days and production rates 1.79 +/- 0.18 vs 13.2 +/- 2.1 mg/kg X day. Two explanations for these differences are proposed.

Adult↗
PubMed1985

Effect of alcohol intake on high and low density lipoprotein metabolism in healthy volunteers.

To determine the effect of moderate doses of ethanol on lipoprotein metabolism, the kinetics of [125I]high density apolipoprotein (Apo) A-I and [131I]low density Apo B were examined in 9 normal volunteers before and after regular intake of 60-70 g of ethanol/day. Plasma levels of Apo B and Apo A-I were significantly increased but remained in the normal range. Mean synthesis of Apo A-I and B were increased, respectively, from 12.6 and 13.7 mg/kg per day in the absence of ethanol to 18.8 and 17.1 mg/kg/day after 2 wk of ethanol intake. Fractional catabolic rates for Apo A-I and B increased respectively from 0.204 and 0.340 in the period without ethanol to 0.266 and 0.372 after ethanol. These findings indicate that despite rather moderate increase in both Apo plasma levels, ethanol produced profound alterations in their metabolism, namely increased turnovers.

Adult↗
PubMed1985

Effects of fenofibrate on high and low density lipoprotein metabolism in heterozygous familial hypercholesterolemia.

This study investigates the influence of pharmacological doses of fenofibrate on HDL and LDL metabolism in 5 familial hypercholesterolemia heterozygotes. Fenofibrate lowered plasma low density lipoprotein cholesterol (20%, P less than 0.025), triglycerides (37%: P less than 0.005) and apolipoprotein B (14%: P less than 0.05) but increased apo A-I (20%; P = 0.01). Kinetic studies showed that the drug markedly increased the fractional catabolic rate of LDL-apo B by 59% and its synthetic rate by 36%. Fractional catabolic rate of apo A-I was also increased by 26% but accompanied by a much greater increase of its synthetic rate (49%). Thus the change in balance between catabolism and synthesis of both apoproteins affected by fenofibrate accounts for the observed plasma concentration changes, which may be considered as favourable with regard to the management of atherosclerosis.

Adult↗
PubMed1985

Amyloidosis of the joints: evidence that human hip capsules have a unique predisposition for amyloid of the senile systemic type.

Amyloid-containing tissues were sampled from 19 capsules and 10 cartilages from hip, knee and sternoclavicular joints of 16 elderly patients. Heart ventricles from 3 of these patients were also studied. Histochemistry and immunofluorescence were performed and amyloid fibrils extracted from one hip capsule. The results indicate that 9 of 13 hip capsules contained prealbumin-like amyloid fibril protein ASc1, a finding characteristic of senile systemic amyloidosis. The amyloid of 16 out of 17 other joint structures showed no reaction with anti-ASc1 or antisera to 3 other systemic forms of amyloid, indicating that they represent localized forms of amyloid.

Aged↗
PubMed1985

Changes in apolipoprotein and lipids in patients after surgery.

Plasma levels of apoproteins A-I, A-II and B and apoprotein/lipid ratios were determined in 43 patients (14 male and 29 female) on the second to the sixth day after gastrointestinal surgery. During this period, all the patients received i. v. 5% dextrose solutions only. Apoprotein levels (A-I, A-II and B), total cholesterol, HDL-cholesterol and phospholipid were significantly decreased after surgery but there was no sex differences. Patients undergoing major surgery showed much lower values than the ones undergoing minor surgery. Both the extent of the trauma and the caloric restriction resulting from sole carbohydrate intravenous feeding may be responsible for these changes. Decreased hepatic synthesis combined to a lack of intestinal supply might result in apo A-I and A-II reduction. Repeated determinations of apoprotein levels are proposed as simple means of follow-up for evaluating the degree of recovery of patients undergoing gastrointestinal surgery.

Adult↗
PubMed1983

In vivo metabolism of human apoprotein A-I-phospholipid complexes. Comparison with human high density lipoprotein-apoprotein A-I metabolism.

The metabolism of apolipoprotein A-I was investigated in healthy young adults. The apoprotein was injected intravenously in one of the four following forms: radiolabelled high density lipoproteins, HDL incubated with labelled apo A-I, labelled A-I-dipalmitoyl- or dimyristoylphosphatidylcholine complexes or free apoprotein A-I. The radioactivity-time curves of high density lipoproteins were followed for 15 days. The kinetic studies demonstrate similar fractional catabolic rates, half-lifes and rates of synthesis. Fractional catabolic rate calculated from plasma data was in reasonable agreement with the value derived from the urine/plasma activity ratio. When free apo A-I was injected, the unusual form of the U/P ratio curve is interpreted as the result of different fates of the injected molecules. This study indicates that the half-life of apo A-I seems not to be affected by the form in which the apoprotein is injected and that kinetics of apo A-I-phospholipid complexes may be used as a valid index of apoprotein A-I/HDL metabolism.

Apolipoprotein A-I↗