Biomedical subjects

Sophie Visvikis

Publications and source records attributed to Sophie Visvikis.

39 records · Page 3Linked to original sources

PubMed2002

Apolipoprotein E in apolipoprotein B (apo B)- and non-apo B-containing lipoproteins in 3523 participants in the Stanislas cohort: biological variation and genotype-specific reference limits.

BACKGROUND: Apolipoprotein (apo) E is a component of two major classes of plasma lipoproteins, apo B- (apo E-LpB) and non-apo B-containing (apo E-Lp-non-B) lipoproteins. The factors that affect total apo E in particles [lipoprotein E (LpE), apo E-Lp-non-B, and apo E-LpB], are incompletely characterized. METHODS: We studied the determinants of these lipoparticles in a sample population of presumably healthy individuals: 1784 children (age range, 8-18 years) and 1739 adults (age range, 19-50 years). Serum concentrations of LpE and apo E-Lp-non-B were measured by electroimmunoassays, and the concentration of apo E-LpB was calculated by a difference method. RESULTS: Serum LpE and apo E-Lp-non-B were higher in females than in males. Their concentrations decreased with age until 20-25 years and then increased in men but not in women. apo E-LpB concentrations increased up to 20-25 years and were similar in both sexes. Thereafter, adult men had higher values than women. Individuals carrying the epsilon2 allele had higher mean apo E-Lp-non-B concentrations and lower apo E-LpB concentrations than did individuals carrying the epsilon3 allele. Individuals with the epsilon4 allele showed an inverse profile compared with those with the epsilon2 allele. Age, gender, the common apo E polymorphism, puberty, serum lipid concentrations, and alcohol consumption were significantly associated with total LpE, apo E-Lp-non-B, and apo E-LpB concentrations. Reference limits were established according to age, gender, and the common apo E polymorphism. CONCLUSIONS: Because measurements of LpE, apo E-Lp-non-B, and apo E-LpB concentrations may improve cardiovascular risk assessment, the proposed reference limits will aid interpretation of the results in clinical or therapeutic trials.

Adolescent↗

PubMed2002

Changes in serum apolipoprotein and lipoprotein profile after alcohol withdrawal: effect of apolipoprotein E polymorphism.

BACKGROUND: Apolipoprotein (Apo) E genotype and alcohol consumption or withdrawal strongly affect lipoprotein (Lp) metabolism and, as with any genetic and environmental factors, they might interact. The aim of this study was to investigate this gene/environment interaction by analyzing the effect of the apoE genotype on the alcohol withdrawal-induced alterations in the serum Apo and Lp profile. METHODS: ApoE genotypes and concentrations of serum cholesterol, triglyceride, and Lps containing apoA-I, A-II, B, E, and C-III were determined in 84 male alcohol abusers before and after 3 weeks of abstinence. RESULTS: After withdrawal, concentrations of serum apoA-I, LpA-I, LpA-I/A-II, apoC-III, LpC-III-non-B, apoE, and LpE-non-B significantly decreased, whereas those of triglycerides and apoB increased; levels of cholesterol, LpC-III:B, and LpB:E were not affected. ANOVA shows that apoE polymorphism effects were quite similar before and after alcohol withdrawal on all serum Apos and Lps (the interaction term between withdrawal and apoE genotype was not significant). The only interaction term that was borderline significant (p < or = 0.10) concerned the apoB concentration. Before withdrawal, no association between apoB level and apoE polymorphism was observed, whereas after abstinence, a borderline significant (p < or = 0.10) gradient of concentration across the three groups of subjects (epsilon2 carriers < epsilon3/epsilon3 < epsilon4 carriers) was noticed. CONCLUSIONS: Alcohol abstinence causes major changes in the antiatherogenic Apos and Lps and may increase those known to be atherogenic. Heavy alcohol consumption seems to alter the effect of apoE polymorphism on apoB levels, and further investigations are needed to clarify the mechanisms involved in this phenomenon: a defect in sialylation of apoE, formation of acetaldehyde adducts on apoB, or both.

Adult↗

PubMedDate not supplied

Cytochromes P450 are differently expressed in normal and varicose human saphenous veins: linkage with varicosis.

The expression of cytochrome P450 (CYP) enzymes and cyclo-oxygenases (COX) was investigated in human saphenous veins by reverse transcription-polymerase chain reaction analysis. Non-varicose veins were obtained from patients undergoing aortocoronary bypass grafting, whereas varicose veins were obtained from patients undergoing stripping removal of varicose saphenous veins. In non-varicose veins, CYP1B1, CYP2C, CYP2E1 and CYP4A11 were detected, whereas CYP2J2, CYP3A5, COX-1 and COX-2 were detected almost exclusively in varicose veins. CYP4F2 was not detectable. Except for CYP4A11, the levels of individual CYP mRNA were higher in varicose veins than in control veins. Smooth muscle cell volume, determined by a colour image-analysis system, was increased approximately 1.5-fold in varicose veins. Because CYPs and COXs produce various vasoactive compounds, increased expression of these enzymes could be involved in the impairment of vascular tone and may contribute to varicose pathology. Then, CYP or COX modulators may be potentially active in the treatment of chronic venous insufficiency.

Adult↗