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Biomedical subjects

M Clerc

Publications and source records attributed to M Clerc.

At least 37 records · Page 2Linked to original sources
PubMed1996

The enzymatic antioxidant system in blood and glutathione status in human immunodeficiency virus (HIV)-infected patients: effects of supplementation with selenium or beta-carotene.

To investigate the effects of selenium or beta-carotene supplementation in human immunodeficiency virus (HIV)-infected patients, who are known to have deficiencies of selenium and vitamin A, we evaluated the blood enzymatic antioxidant system, including superoxide dismutase (SOD), selenodependent glutathione peroxidase (GPX), and catalase (Cat); glutathione (GSH) status; and plasma selenium concentration. The placebo group consisted of 18 HIV-infected patients with no supplementation, the selenium group was composed of 14 patients receiving oral selenium treatment, and the beta-carotene group comprised 13 patients receiving oral beta-carotene supplementation. All groups were studied for 1 y. At the beginning of the study, a significantly higher SOD activity (P < 0.001) was observed in all HIV-infected patients compared with uninfected control subjects, and GPX activity at baseline was higher in the placebo (P < 0.004) and selenium (P < 0.014) groups than in the control subjects. These higher enzyme activities could be related to an increased synthesis of these enzymes in erythrocyte precursors under oxidative stress. Moreover, we observed significantly lower GSH values in all HIV-infected patients than in control subjects at the beginning of the study (P < 0.001). After selenium or beta-carotene supplementation, no significant difference was observed for SOD activity compared with baseline. On the contrary, GPX activity increased significantly after selenium treatment (P < 0.04 between 3 and 6 mo), whereas a slight increase was found after beta-carotene treatment. Similarly, a significant increase in GSH values was observed at 12 mo compared with baseline both after selenium supplementation (P < 0.001) and beta-carotene supplementation (P < 0.01). Because GPX and GSH play an important role in the natural enzymatic defense system in detoxifying hydrogen peroxide in water, selenium supplementation could be of great interest in protecting cells against oxidative stress. The lower efficiency of beta-carotene could be attributed to the seriousness of the pathology at the time of recruitment into the beta-carotene group.

Acquired Immunodeficiency Syndrome↗
PubMed1996

[Oxidative stress and malaria. Apropos of 24 cases of Plasmodium falciparum malaria].

Oxidative stress has been suggested to be implicated in malaria. But it is not clear whether its major role is to kill intraerythrocytic parasites or to cause damage to host tissues. We have studied it in 24 European subjects hospitalized in Saint-André hospital, Bordeaux, France for Plasmodium falciparum access returning from a tropical trip, and in a group control of 16 subjects. Malondialdehyde, one of the oxidative stress markers is significantly increased in patients compared to the control group (m = 5.24 vs 2.14 mol/l). At the same time, it is observed a significative decrease in antioxidant factors, vitamin A and vitamin E. We found no relationship of the severity of malaria to the importance of the oxidative stress, and the question whether the oxidative stress attack host tissues or kill parasites remains entire. These observations should be completed by larger studies, particularly to improve malaria treatments available nowadays.

Adolescent↗
PubMed1995

Arbitrarily-primed PCR confirms the differentiation of strains of Ureaplasma urealyticum into two biovars.

Fourteen serotypes are currently recognized in the Ureaplasma urealyticum species. These serotypes have been divided into two genomic clusters or biovars by a large number of typing methods. The parvo-biovar includes strains of serotypes 1, 3, 6 and 14 and the T960-biovar, strains belonging to the ten other serotypes. In this study, arbitrarily primed polymerase chain reaction (AP-PCR) has been applied to the analysis of reference strains of the 14 U. urealyticum serotypes. By using two different sets of 10-mer oligonucleotide primers, the method allowed the clear differentiation between the two known biovars of the species. However, further differentiation within a same biovar was only achieved for a few standard strains of the T960-biovar analysed by using a pairwise combination of primers. The reproducibility of AP-PCR profiles was shown on strains tested after repeated subcultures and with different thermal cyclers. Additional experiments were performed on forty isolates of U. urealyticum recovered from subjects of various origins. They confirmed that AP-PCR was able to identify the strains at the biovar level. With reference to the other typing methods, AP-PCR is easy to perform and can be applied to large numbers of strains for epidemiological purposes.

Bacterial Typing Techniques↗
PubMed1995

Relationship between red blood cell antioxidant enzymatic system status and lipoperoxidation during the acute phase of malaria.

OBJECTIVE: To investigate the relationship between oxidative stress and aggrevation of the disease in patients with malaria. METHODS AND RESULTS: In the present study lipoperoxidation was demonstrated during the acute phase of malaria by a significant decrease in polyunsaturated fatty acids (PUFA). The lowest values of PUFA were obtained for C20:4 and C22:6, which were the main targets of reactive oxygen species (ROS) when parasitemia was higher than 1%. Similarly, plasma vitamins E and A were significantly reduced during the acute phase of malaria owing to their consumption in part as antioxidants. However, evaluation of the antioxidant enzymatic system in red blood cells of malaria patients indicated no significant difference from controls. Only superoxide dismutase activity tended to decrease when parasitemia increased. CONCLUSION: The results suggest that superoxide radicals are the main ROS produced during the acute phase of malaria, and that rejuvenation of RBC during hemolysis involving increased enzyme activities interacts to protect RBC from excessive superoxide radical production.

Acute Disease↗
PubMed1995

Evaluation of red blood cell lipoperoxidation in hemodialysed patients during erythropoietin therapy supplemented or not with iron.

To investigate the effects of erythropoietin (rHuEPO) therapy supplemented or not with iron on hemolysis in hemodialysed patients (HD) we evaluated lipoperoxidation (LPO) by assaying (i) the red blood cell (RBC) antioxidant enzymatic system including superoxide dismutase (SOD), glutathione peroxidase, and catalase (Cat), (ii) RBC polyunsaturated fatty acids (PUFA) and (iii) malondialdehyde (MDA). Group 1 included 12 HD patients, group 2 had 7 HD patients with iron supplementation, group 3 comprised 12 HD patients with rHuEPO therapy and group 4 included 9 HD patients with both iron and rHuEPO therapies. No LPO was found in group 1 as regards MDA and PUFA levels. However, SOD and Cat activities were significantly elevated as compared to controls (p < 0.001). In the second group, a significant decrease in PUFA percentage was observed, particularly in 20:4(n-6) and 22:4(n-6) (the main ones involved in LPO) as compared to the other groups, whereas total MDA level was higher than that of the other groups. Similarly a decreased SOD activity was observed as compared to group 1 (p < 0.001), indicating its inactivation subsequent to an hyperproduction of reactive oxygen species through iron injection. In groups 3 and 4 no change was observed in MDA levels or PUFA percentages indicating no LPO. However, marked differences were observed in the enzymatic defense system. Particularly in group 3, SOD and Cat activities decreased when compared to group 1 (p < 0.001) whereas the association of erythropoietin and iron (group 4) increased the three enzymatic activities (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Lp(a) and weight loss in obese patients].

High concentrations of lipoprotein (a) (Lp(a)) are associated with an increased risk of atherosclerotic vascular disease. Lp(a) synthesis is mainly under genetic control but many endocrine disturbances may modulate Lp(a) plasmatic concentrations. There is no agreement upon Lp(a) variations in patients under a hypocaloric diet. This study was undertaken to assess this point in obese females subjected to a 1100 kcal/d diet. Ninety-two obese patients (42.4 +/- 10.4 yr old, BMI 33.9 +/- 5.6 kg/m2) came once a week as out patients during 9 weeks. Lp(a) concentrations distribution was highly skewed. The threshold Lp(a) concentration for a significant cardiovascular risk is estimated at 0.3 g/l. Concentrations above 0.3 g/l were found in 29/92 patients (31%). If the patients were distributed in 2 groups according to their Lp(a) values (< or = ou > 0.3 g/l), the BMI, total cholesterol or triglycerides were not different. There were no significant correlation between Lp(a) and age, total cholesterol or triglycerides. After 9 weeks BMI and total cholesterol values decreased (-1.6 +/- 3.4 kg/m2 and -0.17 +/- 0.68 mmol/l, respectively). Lp(a) concentrations were unchanged (0.3 +/- 0.3 vs 0.3 +/- 0.3 g/l). There were no significant correlation between Lp(a) variations and age, BMI or initial Lp(a) concentrations. No significant decrease of Lp(a) could be detected even in the sub-group of patients with initial concentrations of Lp(a) > 0.3 g/l or even in a sub-group with Lp(a) > 0.7 g/l (n = 7). Under our conditions, weight loss is not associated with a decrease of Lp(a) concentrations suggesting that in a given obese a single determination is enough to assess his Lp(a)-related atherosclerotic risk.

Adult↗
PubMed1994

Lipoperoxidation in plasma and red blood cells of patients undergoing haemodialysis: vitamins A, E, and iron status.

In 14 patients undergoing haemodialysis, lipoperoxidation (LPO) processes were determined in plasma and red blood cells (RBC) before and after a dialysis session by determining (a) the direct substrate, polyunsaturated fatty acids (PUFA); (b) the end product of LPO, malondialdehyde (MDA); and (c) the hydrophobic antioxidant systems, vitamins A and E. In plasma before dialysis, linoleic and arachidonic acid, and the antioxidant vitamin E, were significantly lowered as compared to the healthy controls (p < 0.05). On the contrary, the free MDA level was enhanced (p < 0.05). These results were emphasized by a dialysis session. In RBC of these patients, no difference in linoleic acid, free MDA, or vitamin E level were observed before or after dialysis when compared to controls. However, only vitamin A was significantly higher in haemodialysis patients (before and after dialysis) and in renal failure patients (p < 0.05) than in the healthy control group. The present results suggest that increased RBC vitamin A may offer some degree of protection against oxidative stress in erythrocytes, but not in plasma where LPO is demonstrated.

Adult↗
PubMed1994

Markedly accelerated catabolism of apolipoprotein A-II (ApoA-II) and high density lipoproteins containing ApoA-II in classic lecithin: cholesterol acyltransferase deficiency and fish-eye disease.

Classic (complete) lecithin:cholesterol acyltransferase (LCAT) deficiency and Fish-eye disease (partial LCAT deficiency) are genetic syndromes associated with markedly decreased plasma levels of high density lipoprotein (HDL) cholesterol but not with an increased risk of atherosclerotic cardiovascular disease. We investigated the metabolism of the HDL apolipoproteins (apo) apoA-I and apoA-II in a total of five patients with LCAT deficiency, one with classic LCAT deficiency and four with Fish-eye disease. Plasma levels of apoA-II were decreased to a proportionately greater extent (23% of normal) than apoA-I (30% of normal). In addition, plasma concentrations of HDL particles containing both apoA-I and apoA-II (LpA-I:A-II) were much lower (18% of normal) than those of particles containing only apoA-I (LpA-I) (51% of normal). The metabolic basis for the low levels of apoA-II and LpA-I:A-II was investigated in all five patients using both exogenous radiotracer and endogenous stable isotope labeling techniques. The mean plasma residence time of apoA-I was decreased at 2.08 +/- 0.27 d (controls 4.74 +/- 0.65 days); however, the residence time of apoA-II was even shorter at 1.66 +/- 0.24 d (controls 5.25 +/- 0.61 d). In addition, the catabolism of apoA-I in LpA-I:A-II was substantially faster than that of apoA-I in LpA-I. In summary, genetic syndromes of either complete or partial LCAT deficiency result in low levels of HDL through preferential hypercatabolism of apoA-II and HDL particles containing apoA-II. Because LpA-I has been proposed to be more protective than LpA-I:A-II against atherosclerosis, this selective effect on the metabolism of LpA-I:A-II may provide a potential explanation why patients with classic LCAT deficiency and Fish-eye disease are not at increased risk for premature atherosclerosis despite markedly decreased levels of HDL cholesterol and apoA-I.

Adult↗
PubMed1994

[Demonstration of the anti-lipid peroxidation effect of 3',5,7-trihydroxy-4'-methoxy flavone rutinoside: in vitro study].

Diosmin (DI) 3'5,7-trihydroxy-4'-methoxy flavone rutinoside is a member of the flavonoid family, some of whom have antioxidant or free radical scavenger properties. Paw oedema induced by doxorubicin in rats is reduced by DI as observed by SAUVAIRE et al (1989). This suggests a free radical scavenger activity for DI. In this work we demonstrate that such activity is able to protect isolated human LDL from oxidation in vitro. The study of the electrophoretic mobility of oxidized LDL and of total-MDA values as lipoperoxidation-marker indicates an oxidation inhibiting effect higher than 70% for 0.16 mM DI in LDL mixtures containing 50 mM Cu2+ or 4.3 mU/ml xanthine-oxidase and incubated during 20 and 6 hours respectively. Owing to the high level of the oxidizing conditions and the vitamin E (48 mM), vitamin A (1.4 mM) and beta-carotene (2.4 mM) content of the LDL mixtures, it is concluded that DI is clearly able to complement the antioxidant effect of isoprenoids which are naturally present in LDL mixtures.

Adult↗
PubMed1994

[In vivo study of the antilipoperoxidant effect of 3',5,7-trihydroxy-4'-methoxy flavone 7 rutinoside].

In 3-month-old Wistar rats carrageenan and CCl4 injected intraperitoneally induce an acute phase reaction which is characterized by a marked increase in alpha 1, alpha 2, beta serum globulins. This reaction corresponds to a large increase in these globulins in the first case and a smaller one in the second. A lipoperoxidant effect is demonstrated by the serum lipoprotein mobility as the lipoperoxidation index (in MDA units) or the decrease in serum vitamin A and E concentrations. This effect is also greater in the first case than in the second one. In the same way the lipoperoxidant effect is shown in liver microsomes but with a lower amplitude in the first case than in the second one. The treatment of rats by intraperitoneal injection of diosmine (150 mg/kg per week) during the 8 weeks which precede the injection of carrageenan or CCl4 results in: i) a marked decrease in the acute-phase reaction and a lower one in the lipoperoxidant effect, in serum; ii) a decrease in the CCl4 induced lipoperoxidant effect in liver microsomes. It may be concluded that diosmine, not injected at the same time as carrageenan or CCl4, but during the previous 8 weeks is sufficiently well distributed in the whole body to produce a marked inhibition of the acute phase reaction and a perceptible effect on lipoperoxidation. It may be considered an effective complement to the natural antioxidant defences of the organism (vitamins A and E).

Acute-Phase Reaction↗
PubMed1994

[Updating of relative data on tocopherols in clinical biochemistry].

The working group on lipophilic vitamins of the FSBC has reviewed current knowledge in the field of tocopherols and tried to summarize the most important and recent aspects that may be useful to clinical practitioners. The molecular structure of tocopherols and tocotrienols, their biogenesis, their analysis in foods, their metabolism in humans, their measurement in biological fluids, and the organism's needs and dietary requirements are reviewed. Their main functions as antioxidants and free radical scavengers are described at the molecular, ultra-structural, cellular and organ levels. The interest of these vitamins in three pathologies in which oxidative-stress has been implicated (atherosclerosis, cancer, kidney failure) is discussed.

Arteriosclerosis↗
PubMed1993

Relationships between age-dependent changes in the effect of almitrine on H(+)-ATPase/ATPsynthase and the pattern of membrane fatty acid composition.

The effects of almitrine on ATPase/ATPsynthase previously described in beef heart mitochondria (Rigoulet et al. (1990) Biochim. Biophys. Acta 1018, 91-97) are also observed in liver mitochondria isolated from rats older than 7 weeks. In contrast, in rats younger than 5 weeks, almitrine at the same concentration has no effect on the ATPase/ATPsynthase complex. This age-dependent action of almitrine is well correlated with age-dependent modifications of two fatty acids: linoleic and docosahexaenoic acids. The possibility of a change in H+/ATP stoichiometry of the ATPase/ATPsynthase induced by almitrine seems related to more general modifications of membrane properties during growth of the rat.

Aging↗
PubMed1993

31P NMR studies of rat liver cold preservation with histidine-buffered lactobionate solution.

The efficiency of a preservation medium, histidine-buffered lactobionate solution (HBLS), was determined by measuring post-ischemic recoveries of ATP and intracellular pH under Krebs-Henseleit buffer (KHB) perfusion. We used NMR spectroscopy to study the effect of 24-h cold ischemia, followed by 4 degrees C then 37 degrees C reperfusion on the isolated rat liver. Three media were compared: University of Wisconsin solution (UW-lactobionate); Bretschneider's solution (HTK); HBLS and HBLS supplemented with 2 mM Gly and 2 mM Cys (HBLSg2) or with 10 mM Gly and 2 mM Cys (HBLSg10). All values were compared to control values measured during pre-ischemic cold perfusion with KHB (ATP = 8.60 +/- 0.6 mumol/g of dry weigh and pH(in) = 7.41 +/- 0.05). The main result from 31P NMR data concerned ATP recovery during cold reperfusion, which was significantly higher in the HBLS group (112 +/- 10%) as compared to the UW and HTK groups (around 66%). The presence of glycine decreased ATP recovery (88 +/- 8% in HBLSg2, 79 +/- 15% in HBLSg10). Higher values of recovered pHin were observed in livers stored in histidine buffered solutions (around 7.30) as compared to UW (around 7.20); histidine was by 13C NMR proved to accumulate in the liver cells, thus ensuring a good buffering capacity. The thermal transition induced a decrease in both ATP level and pHin in all groups. This might be the result of a stimulation of the carbohydrate metabolism (as demonstrated by 13C NMR) especially when glycine was present in the storage solution.

Adenosine↗
PubMed1993

[Interferon and blood tumor necrosis factor in 95 patients with HIV infection].

We have measured TNF-alpha and interferon alpha in 95 HIV positive patients and 20 healthy subjects. TNF-alpha was higher in the HIV+ patients (P = 0.0001) and was correlated to the CD4 cell count (P = 0.02) and cholesterol (negatively) (P = 0.04). Interferon-alpha was correlated to the wasting syndrome (P = 0.002), hypertriglyceridemia (P = 0.004) and haematocrit (P = 0.04).

HIV Seropositivity↗