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Biomedical subjects

A Favier

Publications and source records attributed to A Favier.

At least 37 records · Page 2Linked to original sources
PubMed1997

Combined effects of lipid peroxidation and antioxidant status on carotid atherosclerosis in a population aged 59-71 y: The EVA Study. Etude sur le Vieillisement Artériel.

There are few epidemiologic studies of the effects of lipid peroxidation and antioxidant status on atherosclerosis. The relation of lipid peroxidation evaluated by thiobarbituric acid-reactive substances (TBARS) and biological markers of antioxidant status to ultrasonographically assessed carotid atherosclerosis was examined from baseline data of a longitudinal study on cognitive and vascular aging (Etude sur le Vieillisement Artériel, the EVA Study). The study sample was composed of 1187 mean and women aged 59-71 y without any history of coronary artery disease or stroke. Ultrasound examination included measurements of intima-media thickness (IMT) on the common carotid arteries (CCAs) and at the site of plaques. After adjustment for conventional cardiovascular risk factors, erythrocyte vitamin E was significantly and negatively associated with CCA-IMT in both men and women whereas plasma selenium and carotenoids were not. No association was found between TBARS and CCA-IMT in either sex. However, TBARS were significantly higher in men with carotid plaques than in those without. This association was strengthened in men with concentrations of erythrocyte vitamin E, plasma selenium, and carotenoids below the lowest quartile. Our findings give some epidemiologic support to the hypothesis that lipid peroxidation and low antioxidant status are involved in the early phases of atherosclerosis.

Aged↗
PubMed1997

Vitamin E improves the free radical defense system potential and insulin sensitivity of rats fed high fructose diets.

The purpose of this study was to investigate the effects of vitamin E in rats fed a high fructose diet which leads to insulin resistance, on some components of the free radical defense system and on insulin sensitivity. The rats (postweaning, 50 g) were divided into three groups: the control group (C, n = 16), which received a purified diet containing 60 g/100 g carbohydrates, the high fructose-fed group (FT, n = 16),fed a diet in which 56.8% of the carbohydrate as fructose, and a high fructose and vitamin E-fed group (FVE, n = 16), fed the FT diet supplemented with 3.4 g vitamin E/kg diet (vs. 0.17 g/kg in C and FT groups). The duration of the treatment was 6 wk. Insulin sensitivity was determined in half of the rats in each group using the euglycemic hyperinsulinic glucose clamp technique. The remaining rats were investigated for plasma glucose, insulin, triglyceride and fructosamine concentrations and for components of the free radical defense system. The FT group had a significantly lower insulin sensitivity than the C group. Basal glycemia was not different among the groups. In comparison with the C group, the FT group had a greater lipid peroxidation, as indicated by the higher concentrations of plasma thiobarbituric acid reactive substances (TBARS) and blood disulfide glutathione (GSSG) and the lower Cu-Zn superoxide dismutase (Cu-Zn SOD) activity. These markers approached the values of the controls after addition of vitamin E. Moreover, the FVE group had a higher insulin sensitivity than the FT group, but it remained lower than in the C group. These results show that a high fructose diet in rats leads to insulin resistance and a defect in the free radical defense system. Vitamin E supplementation improves insulin sensitivity in fructose-fed rats.

Animals↗
PubMed1997

[Evaluation of oxidative stress and antioxidant defences in malnourished Moroccan children].

In Morocco, malnutrition is a public health problem. Indeed, 25% of 6- to 60-month-old children suffer from malnutrition. Imbalance between antioxidant protection and prooxidant stress has been reported to accurately predict the survival of malnourished children. Therefore, we determined blood antioxidant vitamins (retinol, alpha-tocopherol and carotenoids), trace elements (serum zinc, copper and selenium) and enzymes (erythrocyte Se glutathione peroxydase and Cu-Zn superoxide dismutase) as well as blood oxidative stress index [ferritine, thiobarbituric-acid reactants (TBARS)] in 21 children suffering from severe malnutrition, 15 children suffering from mild malnutrition and in 20 healthy control children. Selenium, retionol, alpha-tocopherol and carotenoids were significantly decreased in malnourished children. These decreases were related to the severity of malnutrition. Moreover, the percentage of vitamin and trace element concentrations under deficient cutoff were high in malnourished children. On the contrary, TBARS, ferritin and prognostic inflammatory and nutritional index (PINI) were significantly increased in malnourished children. Except for TBARS, these increases were related to the severity of malnutrition. On the other hand, blood retional, alpha-tocopherol, beta-carotene and selenium were negatively related to alpha 1-acid glycoprotein. Blood beta-cryptoxanthin, lycopene, carotenes and copper were positively related to weight. Finally, blood lutein/zeaxanthin and copper were positively related to height. These results confirm the imbalance between antioxidant protective factors and oxidative stress index in malnourished children. Moreover, the decrease in antioxidant protective factors is related to inflammation or stature. These results suggest that antioxidant micronutrient supplementation of the refeeding diet could be required in the nutritional rehabilitation of malnourished children.

Antioxidants↗
PubMed1997

[Dynamic phototherapy: study of anti-tumour potentialities of bis (tri n-hexylsiloxy) silicon phthalocyanine on malignant achromic M6 melanocytes. EPR study of phototoxic mechanism].

Photodynamic therapy of cancerous cells is a technique relying upon the irradiation of tumorous cells after selective incorporation of a photosensitizer. The bis (tri n-hexylsiloxy) silicon phthalocyanine is a second generation photosensitizer. Anti-cancerous potentialities of this molecule have been evaluated against the melanotic M6 cell line. Results have evidenced a high phototoxicity at low concentration and no dark toxicity under the same conditions. EPR studies on the photochemical pathways involved in phototoxicity processes have been realised in solvent and model membranes (liposomes). Results provide evidences for the production of singlet oxygen (1O2) as well as superoxide (02(o)-) and hydroxyl radicals (0OH).

Antineoplastic Agents↗
PubMed1997

Lipid peroxidation level and antioxidant micronutrient status in a pre-aging population; correlation with chronic disease prevalence in a French epidemiological study (Nantes, France).

OBJECTIVE: The general objective of the Etude du Viellissement Arterial (EVA) program is to follow vascular aging and the decline in cognitive functions at the cerebrovascular level longitudinally over a 4-year period. One of the specific objectives of this EVA study is to examine epidemiologically the relationship between the markers of oxidative stress (lipid peroxidation), the antioxidant micronutrient status (particularly of selenium, vitamin E, and the carotenoids) and the prevalence of chronic disorders occurring during the pre-aging period. METHODS: 1389 subjects aged from 59 to 71 years were studied. RESULTS: The concentration of plasma lipid peroxides was higher than in young adults (2.91 +/- 0.38, men; 2.97 +/- 0.40, women (mumol/l). On the other hand, plasma Se (1.09 +/- 0.21, men; 1.10 +/- 0.19, women (mumol/l)), erythrocyte vitamin E (5.32 +/- 1.29, men; 5.52 +/- 1.28, women (mumol/l)), and total plasma carotenoids (2.19 +/- 0.98, men; 3.07 +/- 1.33, women (mumol/l)) were comparable to values in young adults. In our cohort, 40% of subjects had unremarkable medical histories. The disorders most often encountered were lipemia (29.8% of men, 36.1% of women), and hypertension (28.9% of men, 30.4% of women). CONCLUSION: Se and vitamin E levels were raised in cases of lipemia, especially in those treated with fibrates. The mechanism of the increase is unknown. In hypertensives and diabetics, there was a decrease in total carotenoids associated with increased peroxidative risk.

Aged↗
PubMed1997

Effects of trace element and/or vitamin supplementation on vitamin and mineral status, free radical metabolism and immunological markers in elderly long term-hospitalized subjects. Geriatric Network MIN. VIT. AOX.

A randomized double-blind trial was performed in order to assess the efficacity of differing combinations of antioxidant nutrients on biochemical parameters of vitamin and trace element status, immunological parameters and free radical metabolism in elderly long term hospitalized subjects. A total of 756 institutionalized elderly subjects were recruited in 26 nursing homes in different areas of France. Four groups were constituted, receiving daily, for 1 year, either vitamins (beta-carotene, 6 mg; vitamin C, 120 mg; and vitamin E, 15 mg), trace elements (zinc, 20 mg and selenium, 100 micrograms), trace elements associated with vitamins, or a placebo. Biochemical indicators of trace elements and vitamin status and free radical parameters were measured before and after 6 months and 1 year of supplementation. Some immunological markers were investigated initially and after 6 months of supplementation on a subsample of 134 subjects. Mean plasma levels of alpha-tocopherol, gamma-tocopherol, vitamin C, alpha-carotene, beta-carotene and copper increased significantly after 6 months of supplementation in groups receiving vitamins alone or associated with trace elements. Serum selenium concentrations were significantly increased at 6 months of supplementation, and serum zinc only after one year in the trace element groups. Serum lycopene levels were significantly decreased by trace element supplementation. A significant increase in Se-glutathione peroxidase (GPx) levels was observed in groups receiving trace elements alone or associated with vitamins. No effect was noted on superoxide dismutase (SOD) activity or TBARs production. No effect of supplementation was found for in vitro lymphocyte proliferative responses or most lymphocyte subsets, except for a significantly lower percentage of CD2 subsets observed in groups receiving mineral supplementation either alone or associated with vitamins. A significant difference in CD19 subsets was found in groups receiving trace elements. Mean IL-1 production was significantly higher after 6 months of supplementation in the vitamin groups.

Aged↗
PubMed1997

Dietary magnesium intake in a French adult population.

Magnesium intake was assessed using six 24-h dietary records during a 1-year period in 5,448 subjects (3,111 women 35-60 yrs old and 2,337 men 45-60 yrs old) in the SU.VI.MAX cohort, selected at a national level in France. The overall mean dietary intake was estimated at 369 +/- 106 mg/day in men and 280 +/- 84 mg/day in women. 77 per cent of women and 72 per cent of men had dietary magnesium intakes lower than recommended dietary allowances; 23 per cent of women and 18 per cent of men consumed less than 2/3 of these RDA. A strong positive correlation existed between energy and magnesium intake (r = 0.79; p < 10(-4)). Slight variations were observed according to socio-professional and educational levels and place of residence. Cereal products represented the main contribution in both men (21 per cent) and women (19.8 per cent). In men, the second source was represented by alcoholic beverages (11.7 per cent), which were a lower source of magnesium in women (5.5 per cent). Dairy products, vegetables, meat and poultry were the other main sources of dietary magnesium intake.

Adult↗
PubMed1996

5-Hydroxymethyluracil excretion, plasma TBARS and plasma antioxidant vitamins in adriamycin-treated patients.

The thymine oxidative lesion-5-hydroxymethyluracil (HMUra)-was measured in urine collected from cancer patients. These patients all received chemotherapy using Adriamycin. Adriamycin (ADR) intercalates DNA coils and interferes with normal cell metabolism through diverse biochemical mechanisms that may explain its different actions. The anticancer action of ADR could derive from its interaction with topoisomerase II, resulting in DNA nicking followed by DNA fragmentation and apoptosis. Side effects of ADR-mainly its cardiotoxicity-may derive from the fact that ADR generates superoxide and hydroxyl radicals in two ways: redox-cycling and a Haber-Weiss type reaction due to Fe-ADR complexes. The oxygen free radicals, particularly .OH, are thought to be produced by ADR directly in genomic material and attack all its components. 5-Hydroxymethyluracil is a thymine lesion provoked by these attacks, and it has been proposed as a marker of DNA alterations. In this article, we report the results of a study involving 14 cancer patients treated with ADR. We found that urine HMUra is significantly increased by the anticancer therapy (HMUra (nmol/24 h): 74.4 9.46 vs. 96.3 8.74; p < .01), this increase reveals a higher risk of mutagenesis. Our study is the first to show an in vivo alteration of DNA by ADR. Results also show that thiobarbituric acid reactants increase significantly, and that the vitamin levels for retinol and alpha-tocopherol, which are antioxidant vitamins, are lower at the end of chemotherapy. We suggest to supplement these patients with vitamins A and E, and selenium to reduce the side effects of ADR.

Adult↗
PubMed1996

Increase in glutathione peroxidase activity in malaria parasite after selenium supplementation.

Glutathione peroxidase (GPx), a key enzyme involved in the detoxification of many peroxides, has been investigated in two malaria parasite species: P. yoelii in vivo (murine malaria) and P. falciparum in vitro (human malaria). We demonstrate the presence of an endogenous GPx activity in these two Plasmodia species. Enzymatic assays and the use of specific substrates and inhibitors allowed us to determine that the activity is selenium dependent. As this activity was shown to be lower in P. falciparum than in P. yoelii, and selenium levels were found to be low in culture medium and culture red blood cells, we hypothesized that a severe selenium deficiency could be responsible for this difference. After selenium supplementation, with either sodium selenite or selenocystine, we observed an increase in growth of P. falciparum only in with sodium selenite, whereas higher GPx activities were noted in parasites grown in media supplemented with both. An increase in GPx activities was also observed in parasites that had undergone an experimental oxidative stress with TBOOH. As the erythrocyte is unable to synthesize new proteins, these results provide further evidence for the existence of an endogenous parasitic selenium-dependent glutathione peroxidase.

Animals↗
PubMed1996

Effect of selenium supplementation on biological constants and antioxidant status in rats.

Oxygen-derived free radicals are currently suspected to be widely involved in the aetiology of several clinical disorders. In animals as well as in man, antioxidant trials are often undertaken to prevent oxidative stress. Among antioxidant molecules selenium has been largely studied. This study shows that plasma Se level is not a good index of Se status in the organism, at least at high levels of selenium. Red blood cell Se seems to be a more reliable index of Se status and could replace plasma Se level in the supplementation trials both in animals and humans. Se supplementation did not result in a significant decrease in oxidative stress markers as evaluated by blood and tissue malondialdehyde contents in healthy animals. Furthermore, heart function was altered and plasma Alanine aminotransferase activity was significantly increased in the selenium-supplemented group, which could reflect a slight subtoxic effect of selenium supplementation at the level used here. In view of the results presented, the maximum selenium content in animal diet in selenium supplementation experiments should not be higher than 2 mg/kg.

Animals↗
PubMed1996

Analyzed dietary intakes, plasma concentrations of zinc, copper, and selenium, and related antioxidant enzyme activities in hospitalized elderly women.

OBJECTIVE: The purpose of the study was to assess the actual dietary intakes of zinc (Zn), copper (Cu) and selenium (Se) intakes in relation with some indicators of trace element status in a selected group of hospitalized elderly patients. SUBJECTS: 24 elderly women aged 76-99 years were recruited in the Geriatric Department of the Grenoble University Hospital. MEASURES OF OUTCOME: Zn, Cu, and Se dietary intakes were estimated by duplicate portion analysis. Plasma trace element concentrations, Cu-Zn superoxide dismutase (Cu-Zn SOD) and Se glutathione peroxidase (Se GSH-Px) activities were determined in parallel. RESULTS: Mean daily intakes of Zn (5.6 mg), Cu (0.67 mg), and Se (23 micrograms) were low, in relation with poor energy intake and nutrient densities. Zn and Se levels in plasma were lower and plasma Cu increased compared to reference values obtained from healthy younger subjects. Thirty-eight percent of the elderly patients had plasma Zn concentrations < 10.7 mumol/l, but Cu status appeared adequate as suggested by the lack of decline in Cu-Zn SOD activity. A high proportion of plasma Se concentrations < 0.76 mumol/l and the parallel decrease in erythrocyte and plasma GSH-Px activities suggest a Se deficiency in this population. CONCLUSION: Our findings indicate that French hospitalized elderly patients may be at risk of Zn and Se marginal status and present altered antioxidant defenses in relation with low dietary intakes. It underlines the interest of supplementation studies in this population.

Aged↗
PubMed1996

Rapid high-performance liquid chromatographic assay for salicylic acid in plasma without solvent extraction.

The in vivo measurement of highly reactive free radicals, such as the hydroxyl radical (oOH), in humans is very difficult, if not impossible. Specific markers, based on the ability of oOH to attack aromatic molecules and produce hydroxylated compounds, are under investigation. In vivo radical metabolism of salicylic acid produces two main hydroxylated derivatives: 2,3- and 2,5-dihydroxybenzoic acid (DHBA). The measurement of 2,3-DHBA, following oral administration of salicylic acid or its acetylated form (aspirin), is proposed for the assessment of in vivo oxidative stress. The intensity of oxidative stress is a function of the ratio of dihydroxylated derivatives to salicylic acid rather than the absolute dihydroxylated derivatives levels. Consequently, a simple, accurate, and sensitive assay of the salicylic acid level in plasma is needed to investigate the in vivo free radical production. In this work, a rapid and sensitive method is presented that is useful for the quantitation of salicylic acid in biological fluids. The methodology uses high-performance liquid chromatography with spectrophotometric detection for the identification and quantitation of salicylic acid without organic extraction. A detection limit of less than 5 mumol is achieved with spectrophotometric detector responses that are linear over at least 6 orders of magnitude. Plasma concentrations of salicylic acid determined by the present technique are reported following the administration of 1000 mg aspirin in 20 healthy subjects.

Chromatography, High Pressure Liquid↗
PubMed1996

Photodynamic effects of hypericin on lipid peroxidation and antioxidant status in melanoma cells.

Photodynamic-induced cytotoxicity by hypericin (HYP) was studied on three human melanoma cell lines: one pigmented cell line (G361) and two amelanotic cell lines (M18 and M6). No significant variation in the rate of uptake and in the maximum level of HYP incorporation for the different cells was observed. In the dark, no cytotoxicity was observed in the range 0-10-6 M HYP for the three cell lines. Amelanotic cells were found to be more sensitive than pigmented cells to irradiation of HYP with visible light (lambda > 590 nm). In addition, for the three cell lines HYP-induced photocytotoxicity was found to be drug-dose and light-dose dependent. Under the conditions used, thiobarbituric acid-reacting substances (TBARs) were significantly increased in amelanotic cells after irradiation (P < 0.0001). By contrast, the amount of TBARS remained unchanged in pigmented cells. Antioxidant defenses including enzymes and glutathione (GSH) were assayed before and after HYP photosensitization. Significantly increased total SOD activity was observed after photosensitizaton for amelanotic cells (P < 0.05), while glutathione peroxidase (GSHPx) and catalase (Cat) activities but also GSH levels were significantly decreased (P < 0.01). In pigmented cells a significantly increased Cat activity was found (P < 0.05), whereas GSHPx was unaffected after irradiation. It can be inferred that (a) HYP may be an effective PDT agent for melanoma and (b) there is a relationship between melanin content and sensitivity to HYP phototoxicity in human melanoma cells.

Anthracenes↗
PubMed1996

Micronutrient status in elderly people. Geriatrie/Min. Vit. Aux Network.

A biochemical assessment of the vitamin and trace element status of 756 institutionalized elderly men and women, 66-103 years old (average 83.5 +/- 7.6 y), was conducted in 26 nursing homes in different areas of France. Serum concentrations of beta- and alpha-carotene, beta-cryptoxanthin, lycopene, retinol, alpha- and gamma-tocopherol, vitamin C, zinc and selenium were measured. A difference in biochemical markers according to sex was observed for vitamins E and C: elderly women had higher levels of alpha-tocopherol and vitamin C than elderly men. When expressed as a ratio of cholesterol, the difference between sexes for alpha-tocopherol disappeared. Simple regression analysis showed that most vitamins and trace elements were significantly negatively correlated with age. A high prevalence of low concentrations of vitamin C, zinc and selenium was revealed.

Aged↗
PubMed1996

Effect of 6 month supplementation with different combinations of an association of antioxidant nutrients on biochemical parameters and markers of the antioxidant defence system in the elderly. The Geriatrie/Min.Vit.Aox Network.

OBJECTIVES: To study the effect of supplementation with an association of small physiological amounts of antioxidant nutrients upon biochemical parameters and indicators of oxidative stress and antioxidant enzymes. DESIGN: The study included a double-blind placebo-controlled design. SETTING: Nursing homes in different areas in France. SUBJECTS: 575 elderly long term hospitalized subjects aged 65-103 years. INTERVENTION: Four groups were compared. They received daily: (V) vitamins (vitamin E, 15 mg and vitamin C, 120 mg) and beta-carotene, 6 mg; (T) trace elements (zinc, 20 mg, selenium, 100 micrograms); (VT) vitamins associated with trace elements; or (P) a placebo. Biological markers of vitamin and trace element status, and free radical parameters were measured initially and after 6 months of supplementation. RESULTS: An analysis of variance indicated a significant effect of vitamin supplementation on serum alpha-tocopherol, beta-carotene and vitamin C, a significant effect of trace element supplementation on serum zinc and both a significant trace element and a vitamin-trace element interaction on serum selenium. We observed significant effects of both trace element and vitamin supplementation on GPx activity (P < 0.01), an effect of vitamin supplementation on SOD activity (P < 0.05). CONCLUSION: Our results indicate that short-term supplementation with moderate doses of antioxidant vitamins and trace elements in elderly subjects clearly improves both non-enzymatic (alpha-tocopherol, beta-carotene, vitamin C) levels and enzymatic antioxidant (GPx and SOD) activity.

Aged↗
PubMed1995

High-performance liquid chromatography-electrochemical determination of salicylate hydroxylation products as an in vivo marker of oxidative stress.

The in vivo measurement of highly reactive free radicals, such as hydroxyl radical (.OH), in humans is very difficult if not impossible. Specific markers are currently under investigation (amino acid hydroxylatin, protein, DNA adducts, and aromatic probes). They are based on the ability of .OH to attack aromatic molecules to produce hydroxylated compounds that can be measured directly. In vivo, radical metabolism of salicylic acid produces two main hydroxylated derivatives, i.e., 2,3- and 2,5-dihydroxybenzoic acid (2,3- and 2,5-DHBA). The measurement of 2,3-DHBA, following oral administration of salicylate or its acetylated form (aspirin), has been proposed for assessment of in vivo oxidative stress. In this work, a sensitive method for the detection of in vivo .OH generation is presented. The methodology employs a high-pressure liquid chromatography with electrochemical detection for the identification and quantification of the hydroxylation products from the reaction of .OH with salicylate. A detection limit of less than 0.1 pmol for the hydroxylation products has been achieved with electrochemical detector responses which were linear over at least five orders of magnitude. Using this technique, we measured plasma levels of 2,3- and 2,5-DHBA and dihydroxylated derivatives/salicylic acid ratios following the administration of 1000 mg aspirin in 20 healthy subjects. In the same individuals, plasma levels of thiobarbituric acid reactants (TBARs), a major index of lipid peroxidation, were also measured and correlation with hydroxylated products was sought. The plasma level of TBARs was positively correlated with the 2,5-DHBA/salicylic acid ratio, but not with the absolute plasma level of 2,3-DHBA.

Adult↗
PubMed1995

Effect of double-blind cross-over selenium supplementation on lipid peroxidation markers in cystic fibrosis patients.

Lipid peroxidation was assessed in 27 cystic fibrosis children during a double-blind selenium supplementation study (2.8 micrograms of sodium selenite per kg per day) with a placebo control and inversion of treatment periods. Simultaneously, 17 healthy children living in the same area were also investigated as control subjects. Before any treatment whatsoever and despite a selenium status close to those of control subjects, cystic fibrosis patients showed significant increase in plasma lipid peroxidation markers. Thiobarbituric acid reactants (TBARs) were normalized after the first treatment period of 5 months in both cystic fibrosis groups receiving either selenium supplementation or placebo. In this latter group, TBARs were reduced despite a significant decrease in plasma selenium concentrations as compared with the control group. Organic hydroperoxide concentrations were also simultaneously normalized in both cystic fibrosis groups at the end of the second treatment period. These results showed that improvement of lipid peroxidation markers was not related to the selenium supplementation. Nevertheless, oxidative stress sustained by cystic fibrosis children must be taken into account so that it does not aggravate the prognosis of the disease.

Adolescent↗