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Biomedical subjects

M Rosseneu

Publications and source records attributed to M Rosseneu.

At least 145 records · Page 8Linked to original sources
PubMed1986

Apolipoprotein and lipid composition of plasma lipoproteins in neonates during the first month of life.

In this study the lipid and apoprotein profiles were investigated in newborns at 0, 7, and 30 days of life. The plasma lipoproteins were separated both by ultracentrifugation and gel filtration in order to compare the patterns obtained by the two techniques. At birth, the apo E concentration is comparable to that measured in adults, but its distribution among lipoproteins is significantly different as more than 80% of the plasma apo E belongs to high-density lipoproteins (HDL). At 7 and 30 days the plasma apo E concentrations are close to the values at birth, but a significant redistribution occurs from HDL to very low-density lipoproteins. By analogy with apo B, the plasma apo CIII concentration is low at birth and increases between 0 and 7 days by a factor of about two. Plasma triglycerides increase significantly during the first week of life so that the apo CIII increase is most pronounced in very low-density lipoproteins. These lipoproteins therefore become enriched in apo E, apo CIII and triglycerides between 0 and 7 days. At birth, a distinct HDL fraction, enriched in apo E, apo AII and cholesterol (HDLE), could be detected. To compensate for the low LDL levels, this HDLE fraction might function as an additional source for cholesterol delivery to peripheral tissues via the apo (B, E) receptor. At later age, low-density lipoprotein synthesis is enhanced, apo E is transferred to very low-density lipoproteins, and cholesterol delivery via the HDLE becomes less important.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1986

Human apolipoprotein C-II quantitation by sandwich enzyme-linked immunosorbent assay.

A specific, sensitive and accurate, non competitive enzyme-linked immunosorbent assay was developed for the quantitation of human apolipoprotein C-II. Using apolipoprotein C-II and apolipoprotein C-III immunosorbent columns, monospecific anti-apolipoprotein C-II antibodies were prepared for coating and for the preparation of a peroxidase-antibody conjugate. The assay is sensitive down to 0.25 ng apolipoprotein C-II per assay and precise, with mean intra- and inter-assay coefficients of variation of 3.1% and 7.9% respectively. The apolipoprotein C-II concentrations in normolipaemic and hyperlipaemic plasma were not affected by delipidation, and increased only slightly after treatment with detergents or urea. The mean plasma apolipoprotein C-II concentration in a group of 30 normolipaemic subjects, was 33.1 +/- 7.5 mg/l. All hypertriglyceridaemic subjects had significantly elevated apolipoprotein C-II plasma concentrations, which were most pronounced in Fredrickson type III and type V patients. The apolipoprotein C-II profiles, obtained by column fractionation of 6 normolipaemic and 11 hypertriglyceridaemic plasmas, demonstrated a shift of apolipoprotein C-II towards the triglyceride-rich lipoproteins in hypertriglyceridaemic subjects.

Amino Acid Sequence↗
PubMed1986

Metabolic effects of a biphasic oral contraceptive preparation containing ethinyloestradiol and desogestrel on serum lipoproteins and apolipoproteins.

The effect of the administration of a biphasic oral contraceptive containing ethinyloestradiol and desogestrel on the distribution and composition of serum lipoproteins was studied in a group of 17 healthy female volunteers. The women were treated for a period of 6 months and compared with a control group of ten untreated volunteers. The serum lipoproteins were fractionated by density gradient ultracentrifugation into very low density lipoproteins (VLDL), low density lipoproteins (LDL), and into the high density lipoprotein (HDL) subfractions 2 and 3 (HDL2, HDL3). Lipids and apolipoproteins were assayed in the various fractions. No modification of either the lipid or apolipoprotein concentrations was observed in the control group. In the treated group, sex hormone-binding globulin (SHBG) and cortisol-binding globulin (CBG), and the serum content of cholesterol, triglycerides, HDL-cholesterol, apolipoprotein A-I (apo A-I) and apolipoprotein A-II (apo A-II) increased significantly after 3 and 6 months. The cholesterol and apolipoprotein B (apo B) content of VLDL increased significantly after 3 and 6 months, but remained unchanged in LDL. High density lipoprotein subfraction 2 (HDL2)-cholesterol was significantly increased after 3 and 6 months but apo A-I only after 6 months. Since apo A-II did not change, the apo A-I/A-II ratio increased significantly after 6 months of treatment. In the HDL3 fraction, the apo A-I increase was significant after 3 and 6 months, while the increase of apo A-II was significant after 6 months. The apo A-I/A-II ratio remained constant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Apolipoprotein E quantified by enzyme-linked immunosorbent assay.

We developed a sensitive, specific "sandwich"-type enzyme-linked immunosorbent assay in which affinity-purified antibodies are used for coating and also for preparing an antibody-peroxidase conjugate to quantify apolipoprotein E in serum and in its lipoprotein fractions. This technique is rapid (results within 5 h), precise (mean intra- and interassay CVs 4.3 and 8.2%, respectively), accurate, and simple to perform. Sample pretreatment did not enhance apo E immunoreactivity. For 47 normolipidemic subjects, the mean apo E concentration was 38.11 (SD 11.1) mg/L. Above-normal apo E concentrations were measured in all types of hyperlipoproteinemia, especially types III and V. Apo E correlated with triglyceride (r = 0.58) and cholesterol concentrations (r = 0.60). As determined by gel filtration, hypertriglyceridemia was associated with a redistribution of apo E towards the triglyceride-rich lipoprotein fractions, which contained 77.1% (SD 16.8%) of total plasma apo E in Fredrickson type V patients, compared with 12.5% (SD 6.3%) in normal persons.

Antibody Formation↗
PubMed1985

Hydrolysis of very-low-density lipoproteins labeled with a fluorescent triacylglycerol: 1,3-dioleoyl-2-(4-pyrenylbutanoyl)glycerol.

The fluorescent triacylglycerol (DPBG) 1,3-dioleoyl-2-(4-pyrenylbutanoyl)glycerol was incorporated into plasma very-low-density lipoproteins (VLDL) to form DPBG-VLDL. In the presence of albumin, the addition of milk lipoprotein lipase to DPBG-VLDL hydrolyses DPBG together with the VLDL triacylglycerol and pyrenyl fatty acids are transferred to albumin. As a consequence the monomer fluorescence increases while that of the excimer decreases [Mantulin, W. W., Massey, J. B., Gotto, A. M., Jr & Pownall, H. J. (1981) J. Biol. Chem. 256, 10815-10819]. The relationship of the intensity of the excimer at 475 nm to that of the monomer at 396 nm was measured before and after lipolysis of VLDL by milk lipoprotein lipase. These fluorescent changes parallel the release of free fatty acids from VLDL and their uptake by albumin. The rate of increase of monomer to excimer fluorescence was dependent upon the enzyme, substrate and albumin concentration. The lipolysis reaction, as monitored by fluorescence changes, followed Michaelis-Menten kinetics with a Km of 1.7 M for milk lipoprotein lipase. The use of the fluorescent triacylglycerol probe increases the sensitivity of the technique by a factor 50-80 compared to a technique previously reported using a fluorescent phospholipid. The present method is applicable to 2-10 micrograms triacylglycerol corresponding to about 50-100 microliters of newborn plasma or 30-50 microliters normal adult plasma. The use of an Airfuge ultracentrifuge for VLDL isolation, in conjunction with that of DPBG as a fluorescent probe enables a rapid study of VLDL lipolysis on minimal sample amounts. It can therefore be easily applied to normal and dyslipoproteinemic samples and to the newborns.

Albumins↗
PubMed1985

Immunonephelometric quantitation of the apolipoprotein C-III in human plasma.

A quantitative assay, based on endpoint immunonephelometry, was developed for human apolipoprotein C-III (Apo C-III) in plasma and lipoprotein fractions. The standard curve was constructed either with purified Apo C-III2 as a primary standard or with plasma as a secondary standard. It was linear between 50 and 400 ng Apo C-III per sample, corresponding to 1 microliter undiluted plasma. The intra- and interassay coefficients of variation (CV values) were 2.2 and 6.3%, respectively. The Apo C-III immunoreactivity was not influenced by detergents, denaturants nor by delipidation. The use of a non-ionic detergent (Apovax, 0.1 g/l) avoided the need for organic solvent extraction for plasma containing up to 4 g of triglycerides/l by reducing the sample turbidity. As measured in 126 normolipidemic subjects, the plasma Apo C-III concentration was 0.118 +/- 0.028 g/l (mean +/- SD). Apo C-III concentrations were only slightly elevated in patients with Fredrickson type IIa hyperlipoproteinaemia. The Apo C-III levels were nearly 3 times higher in type I, IIb, III and IV patients, while subjects with type V hyperlipaemia had about a 5-fold increase in Apo C-III compared to the healthy. The plasma Apo C-III values were strongly correlated with the plasma triglyceride concentrations (r = 0.80, n = 201). The Apo C-III distribution among the various lipoprotein fractions showed a higher proportion of Apo C-III in VLDL in hypertriglyceridaemic subjects compared to normolipaemic subjects.

Apolipoprotein C-III↗
PubMed1985

Lipoprotein distribution and composition in the human nephrotic syndrome.

Plasma lipoprotein profiles were quantitated in 9 patients with the nephrotic syndrome. Six subjects were studied both during an active proteinuric phase and during a remission phase without proteinuria. During the proteinuric phase, the plasma triglyceride, cholesterol and apo B levels were markedly increased, whereas the HDL cholesterol, apo A-I, and apo A-II concentrations were normal. Analysis of the distribution and composition of the lipoprotein subclasses, separated by isopycnic ultracentrifugation, showed typical patterns characterized by: (1) elevated apo B-rich VLDL and LDL fractions, (2) the presence of a denser LDL subfraction, floating at d 1.053 g/ml, which contained about 35% of LDL cholesterol and apo B and (3) a redistribution among HDL subclasses. The HDL2b (d 1.063-1.100 g/ml) fraction was markedly decreased, while the HDL2a + 3a (d 1.100-1.150 g/ml) and HDL3b + 3c (d 1.150-1.210 g/ml) subclasses were moderately elevated. The decreased cholesterol and apo A-I contents of HDL2b therefore counterbalanced their increase in HDL2a + 3a and HDL3b + 3c, resulting in normal plasma HDL cholesterol and apo A-I concentrations. When reinvestigated during a remission phase without proteinuria, the nephrotic patient's overall lipoprotein distribution and composition were similar to those in healthy controls. The combination of several factors such as the presence of elevated apo B-rich VLDL, IDL and LDL, together with decreased HDL2 cholesterol and HDL2 apo A-I suggests that nephrotic patients are at increased risk for atherosclerosis.

Adolescent↗
PubMed1985

Changes in the distribution and composition of high-density lipoproteins in primary hypothyroidism.

The distribution and composition of high-density lipoprotein (HDL) subclasses were investigated in 14 women with severe hypothyroidism who were studied before and during treatment. The plasma concentrations of triglycerides, total cholesterol, HDL cholesterol, and of the apoproteins (apo) A-I, B, and E were increased in the hypothyroid state, while the apo A-II levels did not change significantly. After normalization of the thyroid function tests, the lipid and apoprotein levels were similar to those of normal individuals. Isopycnic ultracentrifugation in the density range 1.020 to 1.210 g/mL showed increases of both cholesterol and apo B in very-low-density lipoprotein (VLDL) and in low-density lipoprotein (LDL). The distribution of the HDL subclasses was modified in the hypothyroid subjects; both the less dense HDL fraction (d 1.063 to 1.100 g/mL; HDL2b), and the denser subclass (d 1.150 to 1.210 g/mL; HDL3b+3c) were increased, while the intermediate density subfraction (d 1.100 to 1.150 g/mL; HDL2a+3a) did not vary significantly. This redistribution of the HDL subfractions was associated with increased concentrations of cholesterol, phospholipid, and apo A-I in HDL2b, and of phospholipid and apo A-I in HDL3b+3c. Treatment of hypothyroidism decreased the concentrations of these fractions, and HDL2a+3a became the major HDL subclass in the euthyroid state. The particle sizes within HDL subfractions, measured by polyacrylamide gradient gel electrophoresis, were identical in the untreated and treated patients. The increased mass of protein and lipid within HDL2b and HDL3b+3c could therefore be attributed to an accumulation of identical-sized particles. The overall lipid and protein composition of the HDL lipoproteins was similar before and during treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

The pharmacokinetics of ciprofloxacin in patients with impaired renal function.

Pharmacokinetics of ciprofloxacin after single oral administration of 250 mg were studied in patients with and without renal failure. Ciprofloxacin concentrations were measured by HPLC. The elimination half-life was 8.7 +/- 0.9 h (mean +/- S.E.M.) in six renal failure patients not on haemodialysis, as compared to 4.4 +/- 0.2 h in six patients with normal renal function. The urinary recovery of unchanged ciprofloxacin was 5.3 +/- 1.7% of dose over 24 h in the renal failure patients, as compared to 37.0 +/- 3.7% in the patients with normal renal function. In haemodialysis patients, the half-life was 5.8 +/- 0.9 h on an interdialysis day, and 3.2 +/- 0.4 h during haemodialysis.

Administration, Oral↗
PubMed1985

Hyperthyroidism influences the distribution and apolipoprotein A composition of the high density lipoproteins in man.

Hyperthyroidism has a different influence on the major high density lipoprotein (HDL) components cholesterol, apoprotein (apo) A-I, and apo A-II. To characterize in greater detail the alterations induced by hyperthyroidism within the HDL subclasses, we investigated HDL distribution and composition in 11 hyperthyroid women before and during treatment. The plasma concentrations of total cholesterol, HDL cholesterol, phospholipids, apo A-I, and apo B were decreased when the patients were hyperthyroid compared with the values during treatment. Apo A-II and apo C-III levels were only slightly lower in the hyperthyroid state. Triglyceride and apo E concentrations did not change significantly during therapy. Analysis of lipoprotein subclasses separated by isopycnic ultracentrifugation revealed 1) marked decreases in low density lipoprotein (LDL) cholesterol, phospholipids, and apo B; 2) less pronounced reductions in the very low density lipoprotein (VLDL) lipid and apo B concentrations; and 3) a consistent decrease in the HDL2b (density, 1.063-1.100 g/ml) fraction in the hyperthyroid patients. The reduction in HDL2b mass was associated with lower concentrations of HDL2b cholesterol, phospholipids, and apo A-I. The HDL2b apo A-II levels remained constant during treatment. Hyperthyroidism, therefore, modified the apo A composition of the HDL2b particles and resulted in a decreased molar apo A-I to apo A-II ratio within HDL2b. Further analysis of HDL particles differing in their apo A composition; i.e. HDL particles containing apo A-I only [(A-I)HDL] or containing both apo A-I and A-II [(A-I + A-II)HDL], by immunological procedures suggested that hyperthyroidism influenced the apo A content of HDL2b mainly by changing the proportions of (A-I)HDL and (A-I + A-II)HDL and the amount of apo A-I associated with (A-I)HDL. Treatment reversed the preferential decrease in (A-I)HDL within the HDL2b subclass. The particle sizes within HDL subfractions, measured by polyacrylamide gradient gel electrophoresis, were similar in the untreated and treated patients. Consequently, the decreased mass of apo A-I and lipids within HDL2b in the hyperthyroid patients could be attributed to a reduced number of identically sized particles within this fraction. These data demonstrate that the thyroid hormones are important regulators of HDL metabolism through their influence on the concentration and distribution of apo A-I.

Adolescent↗
PubMed1985

Enzyme linked immunosorbent assay for human apolipoprotein C-III.

A sandwich enzyme linked immunosorbent assay (ELISA) for apolipoprotein C-III was developed. Anti apolipoprotein C-III immunoglobulins were used both for coating of microtitre plates and for the preparation of an anti apolipoprotein C-III horse-radish peroxidase conjugate. Under optimized assay conditions, the sensitivity lies around 0.3 ng apolipoprotein C-III with a working range of 1 to 6 ng. Standard curves are parallel for purified apolipoprotein C-III, for untreated plasma and for lipoprotein fractions. Delipidation did not affect the content of apolipoprotein C-III in plasma. The assay was evaluated by comparison with an immunonephelometric assay for apolipoprotein C-III, yielding a correlation coefficient of 0.982 (n = 79). The mean intra- and interassay CV for the whole working range of the assay were 3.6% and 4.2% respectively.

Apolipoprotein C-III↗
PubMed1985

Quantification of human serum apolipoprotein AI by enzyme immunoassay.

We developed a quantitative assay for apolipoprotein AI (apo AI) in human serum, using a "sandwich"-type enzyme-linked immunosorbent assay. Diluted serum samples were pipetted into the wells of polystyrene microtiter plates that had been previously coated with purified rabbit anti-human apo AI antibodies. After incubation for 2 h and washing, antibodies conjugated to horseradish peroxidase (EC 1.11.1.7) were added and incubated for 2 h; after further washing, the bound enzyme was assayed by oxidation of o-phenylenediamine. Assay conditions were optimized for the incubation time and the amounts of coating antibodies and conjugate. Assay sensitivity is about 0.5 ng of apo AI, with a working range of 1 to 14 ng, similar to that of radioimmunoassays for human apo AI. The standard curves for apo AI in serum or HDL and for purified apo AI were parallel. Delipidation, heat treatment, or addition of detergents did not affect the amount of immunoassayable apo AI in human serum. The intra- and interassay CVs were 4 and 8%, respectively. Results for 100 serum samples compared well with those by immunonephelometry (r = 0.94).

Apolipoprotein A-I↗
PubMed1984

Serum lipids and apolipoproteins A-I, A-II and B in primary hypothyroidism before and during treatment.

Serum lipids and apolipoproteins (apo) A-I, A-II, and B were measured in twenty-four patients with severe primary hypothyroidism (Thyrotropin above 40 mU/l), before and during 1-thyroxine treatment. Apo A-I, A-II, and B were assayed by immunonephelometry, using monospecific antisera. The serum levels of total cholesterol (TC), of low-density lipoprotein cholesterol (LDLc), and of the major LDL apoprotein, apo B, were markedly increased in the untreated hypothyroid patients compared to the values during therapy (TC: mean +/- SD, 8.87 +/- 2.9 v. 5.48 +/- 1.6 mmol/l; LDLc: 6.66 +/- 2.6 v. 3.78 +/- 1.4 mmol/l; apo B: 1.66 +/- 0.48 v. 1.14 +/- 0.37 g/l; P less than 0.00001 for all variables). High-density lipoprotein cholesterol (HDLc) was slightly higher before than during therapy (1.58 +/- 0.7 v. 1.31 +/- 0.4 mmol/l; P less than 0.05), while the main HDL apoprotein, apo A-I, was significantly elevated (1.49 +/- 0.42 v. 1.13 +/- 0.27 g/l; P less than 0.0002). The increase of the second major HDL apoprotein, apo A-II, was less pronounced (0.33 +/- 0.1 v. 0.30 +/- 0.08 g/l; P less than 0.022). The apo A-I to apo A-II ratio, which reflects the relative concentrations of the HDL subfractions HDL2 and HDL3, was significantly higher before than during treatment (P less than 0.0006). Serum triglyceride levels were moderately elevated in the untreated hypothyroid patients (1.34 +/- 0.6 v. 0.95 +/- 0.4 mmol/l; P less than 0.002). The small decrease in body weight during therapy did not correlate with the changes of the various lipid and apoprotein parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Immunonephelometry of apolipoprotein A-II in plasma.

A quantitative assay based on endpoint immunonephelometry was developed for human apolipoprotein A-II (apoA-II) in plasma or serum. Dilution of plasma samples with a 0.1 mol/L solution of sodium cholate enhanced the quantification. We used either purified apoA-II as the primary standard or plasma as a secondary standard. Results correlated well (r = 0.90) with those by a double-antibody radioimmunoassay for 63 serum samples from both normal and hyperlipemic individuals. The interassay coefficient of variation for the immunonephelometric assay was 7% within a working range between 0.05 and 0.7 microgram of apoA-II per sample (corresponding to a 1500-fold final dilution of serum). No extraction of samples with organic solvent is necessary if the triglyceride concentration is less than 4 g/L.

Apolipoprotein A-II↗
PubMed1984

Lipid binding properties of the Tangier apolipoprotein A-I and its isoproteins.

The apolipoprotein A-I was isolated from the plasma of normal individuals and of three homozygous patients with Tangier disease by immunoprecipitation. The apoA-I isoforms were further fractionated by isofocusing on polyacrylamide gels. The physicochemical behavior of normal and Tangier apoA-I and of the isoproteins-2 and -4 was studied by monitoring the tryptophanyl fluorescence emission as a function of temperature, pH, and under exposure to guanidinium (guanidine) hydrochloride (GdmCl). Lipid-apoprotein complexes were generated by incubation with dimyristoylphosphatidylcholine and isolated by density gradient ultracentrifugation. Our results show that normal apoA-I and its isoprotein-4 associate with lipids to yield a complex containing 150-200 mol lecithin/mol apoA-I. The isoprotein-2 of normal apoA-I and the isoprotein-4 of Tangier apoA-I generate lipid-rich complexes with lecithin, while the isoprotein-2 of Tangier apoA-I shows only a limited association with lipids. ApoA-I normal and Tangier and their isoproteins-4 undergo a structural transition around 45 degrees C, which is not observed in the lecithin-apoA-I complexes. This transition is accompanied by an increased exposure of the tryptophanyl residues to the solvent. This transition was observed for the isoprotein-2 of apoA-I Tangier both in its lipid-free form and in the presence of lecithin. The pH denaturation of apoA-I and of the isoprotein-4 between pH 9 and 13 and between pH 7 and 2 is accompanied by a similar conformational transition. The transition occurs around pH 10.8 for the native apoproteins and is shifted towards respectively higher and lower pH's as result of the protective action of lipid binding on the protein conformation. Such an effect was not observed with the isoprotein-2 of apoA-I Tangier which is denatured at lower pH's both in its native form and in a lipid-protein mixture. Finally the denaturation of apoA-I by GdmCl indicates that apoA-I normal and Tangier undergo structural changes around 1 M GdmCl, whereas the apoA-I-Tangier-lecithin complex is more susceptible to denaturation than the complex with apoA-I normal. These data suggest that the apoA-I normal and Tangier and their isoproteins-4 are able to associate with lipids although the association between apoA-I Tangier with lecithin is weaker than that of apoA-I normal. The isoprotein-2 of normal apoA-I associates to a greater extent with lipids than the isoprotein-2 of Tangier apoA-I, whose structure differs from that of the isoprotein-4.(ABSTRACT TRUNCATED AT 400 WORDS)

Apolipoprotein A-I↗
PubMed1983

Interaction of the serum amyloid A proteins with phospholipid.

The serum amyloid A proteins (SAA) are transported in plasma in association with the high density lipoproteins. We have studied the solution properties of two of the polymorphic forms of SAA, SAA1 and SAA4, and compared the lipid-binding properties of SAA4 to those of the well characterized apolipoproteins, apo-A-I, apo-A-II, and apo-C-III. SAA4 was monomeric at pH 2.9 but considerable self-association was demonstrated at pH 8.2, even in the presence of 1.0 M guanidine HCl. SAA4 differed from the apolipoproteins in its ability to disrupt multilamellar dimyristoylphosphatidylcholine (DMPC) liposomes and generate bilayer discs. Apo-A-I, apo-A-II, and apo-C-III reduced the turbidity of DMPC dispersions at protein:lipid molar ratios of 1:200. SAA4, however, increased turbidity at molar ratios of 1:250 and 1:100 even when preincubated in guanidine HCl before addition to liposomes. Optical density decreased only at ratios of 1:50 and 1:25. At an SAA4:DMPC ratio of 1:50, discoidal particles (long axis, 28.1 nm; short axis, 4.4 nm) were formed which were similar to those produced by apo-C-III. Lipid binding induced changes in SAA4 conformation similar to those observed in the apolipoproteins. The alpha-helical content and intrinsic tryptophanyl fluorescence were increased and quenching of tryptophanyl fluorescence by acrylamide was reduced in the presence of DMPC. In addition, SAA4 as well as the apolipoproteins broadened the range and increased the temperature of the gel-liquid crystal transition temperature of DMPC.

Amyloid↗