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Biomedical subjects

F Parrot

Publications and source records attributed to F Parrot.

15 recordsLinked to original sources

[Homocysteinemia: role in vascular disease].

HEREDITARY DISEASE: Hereditary anomalies of homocysteine metabolism are quite uncommon and manifest by very high homocysteine levels (> 100 mumol/l) and associated homocysteinuria. The risk of premature cardiovascular disease is high. Clinical, biological and epidemiological data accumulated since the 70 s have demonstrated that a moderately elevated serum homocysteine level favors the development of atherothrombosis. PROVEN RISK: The risk of coronary or cerebral events is 1.5 to 3-fold higher for fasting homocysteine levels above 15 mumol/l. These data show that moderately elevated homocysteine level is a powerful cardiovascular risk factor. Further information is however needed to ascertain its frequency in the population and determine whether it is a truly independent risk factor. THERAPEUTIC OPTIONS: Most cases of moderately elevated homocysteine can probably be explained by gene-environment interactions. Homocysteine levels can be lowered by oral administration of vitamin cofactors implicated in homocystein metabolisms: folic acid, vitamin B6, vitamin B12.

Cerebral Infarction↗

Endothelial dysfunction during acute methionine load in hyperhomocysteinaemic patients.

Hyperhomocysteinaemia has been associated with arterial and venous thrombosis possibly by causing damage to the endothelium. We hypothesised that an oral load in methionine, that increases plasma homocysteine, would also result in an increase in biological markers of endothelial or platelet dysfunction. Then we investigated two groups of patients with arterial or venous occlusive disease: 17 with hyperhomocysteinemia and 12 without hyperhomocysteinemia. We measured in both groups plasma soluble thrombomodulin, von Willebrand factor, P-selectin and tissue factor plasma inhibitor before and 6 hours after a load with 100 mg/kg oral methionine. Methionine load resulted in a significant increase in von Willebrand factor in both groups (P<0.02), suggesting that endothelial dysfunction occurs during the load.

Administration, Oral↗

Three months supplementation of hyperhomocysteinaemic patients with folic acid and vitamin B6 improves biological markers of endothelial dysfunction.

Hyperhomocysteinaemia is a risk factor for premature atherosclerosis and venous thromboembolic disease. Supplementation with folic acid and vitamin B6 has been shown to decrease plasma homocysteine but data fail to assess an effect on the progression of vascular disease. We measured plasma homocysteine and two markers of endothelial injury (plasma soluble thrombomodulin and von Willebrand factor) at baseline and after 3 months of treatment with folic acid and vitamin B6. After this treatment there was a significant decrease in fasting soluble thrombomodulin (-15 ng/ml, 95%CI 5-22.2). Von Willebrand factor was significantly raised after methionine load at baseline but did not significantly rise after supplementation.

Adult↗

Mild hyperhomocysteinemia and hemostatic factors in patients with arterial vascular diseases.

Mild hyperhomocysteinemia, due to genetic or to environmental factors, is now recognized as a risk factor for premature arterial disease, including peripheral arterial occlusion, thrombotic stroke and myocardial infarction. It is defined by either an increased level of fasting homocysteine or by an increased level after loading with methionine, which is more frequently altered than the former. We studied the hemostatic parameters in 88 patients with premature arterial disease (mean age 43 +/- 11 years). We confirmed previously known hemostatic alterations described in vascular patients when compared to controls, but found that, among patients, some of these parameters were more altered in hyperhomocysteinemic patients. When fasting homocysteine was increased, higher alterations were found in factors VIIIc, von Willebrand and thombin-antithrombin complexes were more elevated. When post-methionine load homocysteine was increased, alterations in fibrinolytic parameters were more pronounced.

Adult↗

Glyphosate herbicide poisoning: use of a routine aminoacid analyzer appears to be a rapid method for determining glyphosate and its metabolite in biological fluids.

Glyphosate containing herbicides are an alternative to paraquat and are widely used throughout the world. Despite animal studies showing a low mammalian toxicity, human fatalities are reported after suicidal ingestions of glyphosate. Among the numerous analytical methods proposed, the reference method is the HPLC Monsanto procedure which is available in very few laboratories. The Monsanto procedure consists of a pre-column derivatization with detection of the resulting chromophore by HPLC with a variable wavelength UV/VIS detector. We propose a simple and rapid method for the diagnosis and monitoring of glyphosate poisoning. This method uses an aminoacid analyzer (Beckman 6300) with the program for biological fluids. With this procedure the glyphosate and amino methyl phosphoric acid retention times are respectively 1.75 and 3.54 min. This method gives a rapid result. The time between collecting the sample and completing the result is 45 min. This method may be useful for the diagnosis and monitoring of glyphosate poisoning and is easy to perform with an apparatus usually available in every laboratory involved in aminoacid analysis.

Body Fluids↗

Impact of high-flux/high-efficiency dialysis on folate and homocysteine metabolism.

High-flux/high-efficiency (HF/HE) dialysis may have detrimental effects on micro-nutrients and water-soluble vitamins, such as vitamin B6, whose levels are lowered. Folate deficiency may increase cardiovascular risk through an increase in homocysteine (Hcy) serum levels. We therefore investigated the effects of dialysis with a high-flux (HF) membrane on folate and Hcy metabolism. Twelve patients without any folate supplementation, receiving dialysis with a low-flux membrane prior to the study (TO), were switched to dialysis using a HF triacetate membrane for four months (T1, T2, T3, T4) and received an oral daily folate supplementation during the two last months (T3, T4). Mean predialysis plasma folate levels fell dramatically after one month of HF dialysis (T1) and remained significantly lower than the initial level (p<0.05) at T2. Hcy concentrations were high in all patients at TO (mean 47.3 +/- 17.6 microM, normal range 5 to 15 microM). They did not change during the first two months of the study but dropped steeply after the beginning of oral folate supplementation. Folate supplementation should be used in HF/HE dialysis to avoid folate depletion. The combination of folate supplementation and HF/HE may lower Hcy levels and reduce cardiovascular morbidity and mortality in these patients.

Female↗