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B Chadefaux-Vekemans

Publications and source records attributed to B Chadefaux-Vekemans.

At least 19 recordsLinked to original sources
PubMed2006

Prenatal diagnosis of some metabolic diseases using early amniotic fluid samples: report of a 15 years, experience.

BACKGROUND: In the present study, we report the results of 132 prenatal diagnoses performed on chorionic villi and cell-free amniotic fluid obtained simultaneously at 12-13 weeks of gestation. In addition, we report the result of 59 prenatal diagnoses performed at 12-13th week using amniotic fluid only. METHODS AND RESULTS: A total of one fetal loss (1/191) was observed when a sample of amniotic fluid was obtained at around 12-13 weeks, whereas three losses (3/82) were observed after midtrimester amniocentesis. We attribute this finding to the fact that only a very small volume of amniotic fluid was sampled using a very small needle. CONCLUSION: From these data it appears that when a couple is facing a high risk of recurrence of some metabolic diseases, the study of chorionic villus and amniotic fluid sampled simultaneously offers a safe and reliable method of early prenatal diagnosis.

Abortion, Spontaneous↗
PubMed2005

[Homocysteine, folic acid, group B vitamins and cardiovascular risk].

Although there is a high degree of proof relating plasma homocysteine levels to cardiovascular risk, the role of homocysteine as a causal cardiovascular risk factor remains controversial. Prospective long-term clinical trials in high cardiovascular risk populations usually show a positive relationship between plasma homocysteine and the degree of cardiovascular risk. However, shorter term studies and/or those carried out in populations with lower cardiovascular risk show either a weaker correlation or no relationship at all. To date no study has shown proof of the reversibility of cardiovascular risk due to hyperhomocysteinaemia; nevertheless, a number of studies using intermediate criteria support the hypothesis of a benefit due to reduction of plasma homocysteine levels. A number of therapeutic trials published with clinical criteria have not shown convincing results in either direction. A number of interventional trials are underway: notably the SUFOLOM 3 trial in France, and the question of a benefit on cardiovascular risk by reducing homocysteine levels should be answered in the next few years. In the meantime, with the exception of homocysteinuria in which therapeutic strategies have shown their efficacy in the reduction of atherothrombotic risk with high levels of proof, the authors do not recommend the treatment of mild hyperhomocysteinaemia in any clinical setting other than "clinical trials" and certain "compassionate" indications such as early and/or recurrent vascular events associated with hyperhomocysteinaemia in the absence of conventional risk factors.

Cardiovascular Diseases↗
PubMed2002

Improving the prenatal diagnosis of citrullinemia using citrulline/ornithine+arginine ratio in amniotic fluid.

Prenatal diagnosis of citrullinemia is performed using a direct argininosuccinate synthetase (ASS) assay on chorionic villi (CV) and citrulline concentration measurement in early amniotic fluid (AF). Here we report the results of 40 prenatal diagnoses performed using this method, discuss the difficulties encountered in interpreting the results, and propose the use of the citrulline/ornithine+arginine ratio (which is more discriminatory than citrulline concentration alone) when performing prenatal diagnosis of citrullinemia.

Amniocentesis↗
PubMed1999

Effective correction of hyperhomocysteinemia in hemodialysis patients by intravenous folinic acid and pyridoxine therapy.

UNLABELLED: Effective correction of hyperhomocysteinemia in hemodialysis patients by intravenous folinic acid and pyridoxine therapy. BACKGROUND: Folic acid supplementation is only partially efficacious in correcting moderate elevation of plasma total homocysteine (tHcy) concentrations observed in hemodialysis (HD) patients. Experimental and clinical data have suggested that this partial efficacy may be due to impairment of folic acid metabolism to 5-methyltetrahydrofolate (MTHF) and of MTHF transmembrane transport as well. To bypass these difficulties, we assessed the efficacy of intravenous (i.v.) folinic acid, a ready precursor of MTHF, on reducing plasma tHcy concentrations in HD patients. METHODS: In a cohort of 37 patients on intermittent HD treatment, plasma tHcy concentrations were determined before and during i.v. supplementation of folinic acid (50 mg once per week), together with i.v. pyridoxine (250 mg 3 times per week), to prevent vitamin deficiency, particularly in those treated by recombinant erythropoietin. RESULTS: Folinic acid and pyridoxine i.v. supplementation was given for 11.2 +/- 2.45 months (range 7.5 to 17 months). The mean plasma tHcy levels decreased significantly from 37. 3 +/- 5.8 microM at baseline to 12.3 +/- 5.4 microM on folinic acid treatment (P < 0.001). Moreover, 29 of the 37 patients (78%) had normal plasma tHcy levels at the end of follow-up (that is, <14.1 microM, mean 9.8 microM, range 6.2 to 13 microM). No adverse effects attributable to folinic acid treatment were observed during this time. CONCLUSIONS: Intravenous folinic acid therapy (50 mg) once per week associated with pyridoxine supplementation appears to be an effective and safe strategy to normalize plasma tHcy levels in the majority of chronic HD patients.

Adult↗
PubMed1998

Does the polymorphism 677C-T of the 5,10-methylenetetrahydrofolate reductase gene contribute to homocysteine-related vascular disease?

Whether the 677C-T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene acts as a risk factor for homocysteine-related vascular disease remains a matter of debate. Testing for the 677C-T nucleotide substitution and assay of plasma homocysteine were carried out simultaneously in 69 controls and 113 vascular disease patients from the Paris area. The variant gene frequency as well as the variant homozygous genotype frequency were very similar in controls and patients. Conversely, plasma homocysteine levels were substantially higher in patients than in controls. A slight interaction between the 677C-T MTHFR polymorphism and homocysteinaemia was observed in the patient group only, while a negative correlation between fasting homocysteine and plasma folate levels was found in all individuals homozygous for the 677C-T MTHFR genotype, irrespective of vascular disease. These data suggest that the 677C-T MTHFR polymorphism is not a major determinant of the vascular disease but contributes to increased plasma homocysteine concentration in conjunction with low plasma folate levels.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed1998

Carotid atherosclerosis in renal transplant recipients.

BACKGROUND: Cardiovascular accidents are the major cause of morbidity and mortality in renal transplant recipients. However, there is little information concerning carotid atherosclerotic wall changes in renal transplant recipients, their relationship with cardiovascular accidents and their possible association with cardiovascular risk factors in such patients. METHODS: Between April 1991 and December 1997, we prospectively assessed cardiovascular accidents in 79 renal transplant recipients who had received a transplant at our institution before January 1, 1986. Carotid morphology by B-mode ultrasonography, relevant clinical and laboratory cardiovascular risk factors, including lipid abnormalities and total homocyst(e)ine, were determined at the start of the follow-up period. Seventeen healthy subjects matched for age and sex with renal transplant recipients served as controls who volunteered for ultrasonographic examination of carotid arteries. RESULTS: Nine patients experienced cardiovascular events during the period of follow-up. Compared with healthy, age- and sex-matched control subjects (n = 17), the frequency of carotid plaques was higher in renal transplant recipients with cardiovascular events (n = 9), but not in those without such events (n = 70). The frequency of cardiovascular accidents was related to the number of carotid plaques (4, 17 and 24% for no plaque, one plaque and > 1 plaque respectively, P < 0.04). However, by multivariate analysis, serum total cholesterol [odds ratio (OR) of 1.8 for each 1.0 mM, P < 0.07) and the presence of diabetes mellitus (OR of 28.4 for presence, P < 0.01) were the only predictors of cardiovascular events in such patients, whereas the presence of carotid plaques was not. Moreover, neither serum lipoprotein (a) nor total homocyst(e)ine concentrations could be identified as risk factors. CONCLUSIONS: This prospective study shows that although a close association exists between asymptomatic carotid atherosclerosis and cardiovascular accidents in renal transplant recipients with long-term follow-up and relatively good renal function, other potentially modifiable risk factors appear to be better predictors of cardiovascular events. Consequently, the assessment of carotid atherosclerosis may not be clinically useful for the systematic identification of renal transplant recipients with an increased risk of developing cardiovascular events.

Adult↗
PubMed1998

Reliability of biochemical parameters used in prenatal diagnosis of combined methylmalonic aciduria and homocystinuria.

Prenatal diagnosis for combined methylmalonic aciduria and homocystinuria was performed in five at-risk pregnancies by determination of methylmalonic acid (MMA) and total homocysteine (Hcy) in amniotic fluid supernatant. The incorporation rate of [14C] propionate (+/- OHCbl) and the synthesis of cobalamin derivatives in cultured amniocytes were investigated as well as the [14C] MTHF incorporation rate in intact chorion biopsy. Our experience showed that total Hcy and MMA were clearly elevated in amniotic fluid of affected fetuses. Both the study of [14C] propionate incorporation and that of cobalamin synthesis in cultured amniocytes are useful to confirm the results of metabolite determination. The incorporation of [14C] MTHF in intact chorion biopsy seems not to be a reliable diagnostic method.

Amino Acid Metabolism, Inborn Errors↗
PubMed1997

Plasma homocysteine and the extent of atherosclerosis in patients with coronary artery disease.

Homocysteine is a graded risk factor for the incidence of stroke and for the degree of carotid atherosclerosis. Homocysteine is also a graded risk factor for the incidence of myocardial infarction but we do not know its precise relations to the severity of atherosclerosis in coronary patients. Seventy five symptomatic coronary patients were recruited for the study. Fifty of these patients had coronary artery disease only and were compared in a case-control manner to 50 healthy controls matched for age and sex. The 25 other coronary patients had also symptoms in another atherosclerotic territory (cerebral, peripheral or both) and were also compared to 25 matched controls. Mean plasma homocysteine level was significantly higher in coronary patients than in controls (11.7 +/- 0.7 mumol l-1, n = 50 versus 9.9 +/- 0.5 mumol l-1, n = 50, p < 0.05). Homocysteine in patients with symptomatic atherosclerosis in two or three arterial sites was 15.7 +/- 1.5 mumol l-1 which differed significantly from matched controls and from patients with coronary artery disease only (p = 0.01). The extent of coronary atherosclerosis evaluated by an angiographic coronary score correlated weakly to plasma homocysteine levels (r = 0.25, p < 0.05). The patients with both hypertension and high levels of homocysteine (> 11.3 mumol l-1, median value) had more severe coronary atherosclerosis (coronary score of 16.3 +/- 2.3 versus 11.9 +/- 0.9, p < 0.05) and more diffuse atherosclerosis (number of atherosclerotic territories of 1.5 +/- 0.2 versus 1.2 +/- 0.7, p = 0.08) than the coronary patients without this association. There were no other high risk association when considering the other classical risk factors. Thus, the highest levels of homocysteine were present in patients with coronary disease and another symptomatic localisation of atherosclerosis. A small gradient in the extent of coronary atherosclerosis was found with increasing levels of homocysteine. The presence of both hypertension and hyperhomocysteinemia was associated with more severe coronary atherosclerosis.

Biomarkers↗
PubMed1996

[Value of an extensive biological study in venous or arterial thromboses].

OBJECTIVES: The aim of this work is to study the signification of an extensive biological evaluation in patients with "unexplained" thrombosis. We studied 78 patients with more than one arterial and/or venous thromboembolic event. METHODS: Fifty-four patients were admitted for unexplained deep venous thrombosis (group I, n = 19, 9 men and 10 women) and/or arterial thrombosis (group II, n = 35, 21 men and 14 women). A third group (group III) included 24 patients (13 men, 11 women) known to have a pathologic state which can lead to a thrombotic event. RESULTS: The patients in both groups I and II had, more often than normal subjects, a high level of homocysteinemia (26% vs 3%, p < 0.001), anti-beta 2 glycoprotein 1 (18.5% vs 3%, p < 0.001) and antiphospholipid antibodies (13% vs 3%, p < 0.02). We also found a significant association between an increase of erythrocytic aggregation and arterial thrombosis (group II). In the third group, for both arterial (n = 14) and venous (n = 10) thrombosis, we found a high level of anticardiolipin antibodies (25% vs 3%, p < 0.001), anti-beta 2 glycoprotein 1 antibodies (12.5% vs 3%, p < 0.05) and abnormal erythrocytic aggregation (16.5% vs 3%, p < 0.01). In these 3 groups the other studied parameters (Lp(a), platelet aggregation, cryoglobulin, cryofibrinogen, antinuclear antibodies, anticytoplasm antibodies, plasma and urine immunoelectrophoresis, protein C, protein S, antithrombin III, plasminogen) were not different from levels observed in normal subjects. CONCLUSION: An extensive biological analysis, including plasma homocystein level, anticardiolipin antibodies, anti-beta 2 glycoprotein 1 antibodies and a study of the erythrocytic aggregation would appear to be of value in patients presenting recurrent arterial or venous thromboembolic events. Specific therapy can be applied in case of abnormal results continued anticoagulant therapy for anticardiolipin and anti-beta 2 glycoprotein 1 antibodies, and a vitamin therapy for increased homocysteinemia.

Adolescent↗
PubMed1996

Gestational age-related reference values for amniotic fluid amino acids: a useful tool for prenatal diagnosis of aminoacidopathies.

In this study we have measured the concentration of 24 amino acids and total homocysteine in amniotic fluids obtained between the tenth and 32nd week of gestation from pregnancies not at risk for metabolic diseases. These results are used as reference values to which are compared values obtained from pregnancies at risk for citrullinaemia, argininosuccinic aciduria, HHH (hyperornithinaemia, hyperammonaemia and homocitrullinaemia) syndrome, cobalamin metabolism disorders (CblC or CblD), and sulphite oxidase deficiency. We discuss the helpfulness of amino acid analysis in amniotic fluid for prenatal diagnosis of aminoacidopathies.

Amino Acid Metabolism, Inborn Errors↗
PubMed1996

[Hyperhomocysteinemia in coronary artery diseases. Apropos of a study on 102 patients].

Homocystein is at the crossroads of the metabolic pathways of sulphuric amino acids. Homocystinuria is a congenital autosomal recessive disease, usually related to cystathionine beta-synthetase deficiency. Children with homozygotic forms of the disease have early vascular complications which represent the main cause of death. Moderately elevated serum homocystein levels are related to two major genetic factors (heterozygotic cystathionine beta-synthetase deficiency and mutation of the 5-10 methylene tetrahydrofolate reductase) and several minor, genetic and non-genetic factors (folic acid, vitamins B6 and B12 and betain deficiencies). Previous studies have suggested that hyperhomocysteinaemia could be a cardiovascular risk factor. This study was based on 222 subjects including 102 consecutive patients with angiographically documented coronary artery disease and 120 control subjects without vascular disease. No relationship was observed between serum homocystein concentrations and the classical cardiovascular risk factors. Coronary patients had higher average homocystein concentrations than control subjects (11.27 +/- 0.52 vs 8.77 +/- 0.31 mumol/l); p < 0.0001): moreover, the prevalence of hyperhomocysteinaemia (> 15.67 mumol/l) was higher in the coronary group (15.7%) than in the controls (2.5%). A significant relationship was also observed between homocystein concentrations and the severity of the coronary disease (defined by a coronary score) and the number of diseased vascular territories. These results underline the relationship between homocystein and vascular risk, especially that of coronary artery disease. The treatment of hyperhomocysteinaemia by folic acid supplements is effective in correcting plasma levels, without side effects and at a relatively low cost.

Adult↗
PubMed1995

Prenatal diagnosis of the urea cycle diseases: a survey of the European cases.

A European survey of prenatal diagnosis cases involving urea cycle diseases was performed. Citrullinemia was the most frequently investigated disease (108 cases). Other diseases are, in order of frequency, argininosuccinic aciduria (75 cases), ornithine transcarbamylase defect (52 cases), carbamoylphosphate synthetase defect (8 cases), triple H (3 cases), and arginase deficiency (1 case). Only one disease (ornithine transcarbamylase defect) is presently diagnosed using molecular biology methods.

Argininosuccinic Acid↗