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Biomedical subjects

E Postaire

Publications and source records attributed to E Postaire.

At least 19 recordsLinked to original sources
PubMed2001

Differential pattern in circulating nitrogen derivatives, lactoferrin, and anti-lactoferrin antibodies in HIV type 1 and HIV type 2 infections.

HIV-1 infection is associated with a dramatic reduction in antioxidative molecules both at the cellular level and in the circulation. This is particularly so for lactoferrin, an iron-binding protein involved in natural defenses (antimicrobial and antiviral activities, etc.) and found in whole secretions, including milk and mucus. In addition to its ability to chelate iron ions, lactoferrin inhibits hydroxy radical formation and interacts with nitric oxide (NO). Levels of plasma lactoferrin decreased in HIV-1-infected patients in correlation with progression of the disease, and highly specific anti-lactoferrin autoantibodies increased. This profile was specific to HIV-1 infection; it was not found in HIV-2-infected patients. In parallel with the drop in lactoferrin, a marked increase in circulating nitrogen derivatives was observed in HIV-1-infected patients, whereas low levels were found in normal donors and in HIV-2-infected patients. These data suggested hyperstimulation of the NO pathway throughout HIV-1 but not HIV-2 infection. This overproduction of NO could play an important role in the development of AIDS symptoms and signs.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2001

Zinc and diabetes mellitus: is there a need of zinc supplementation in diabetes mellitus patients?

Diabetes mellitus is a group of metabolic disorders, the incidence of which varies widely throughout the world. The treatment of diabetes mellitus includes insulin, oral antidiabetic agents, and dietary regimens. Although the emphasis is on macronutrients intakes, there is strong evidence that there is an abnormal metabolism of several micronutrients in diabetic individuals. Zinc is one of the essential micronutrients of which status and metabolism is altered in this condition. This work is a short review about the close relation among zinc, glucose metabolism, and insulin physiology, as well as about the few experimental data about zinc absorption and zinc supplementation in diabetes mellitus patients.

Diabetes Complications↗
PubMed1997

Evidence for antioxidant nutrients-induced pigmentation in skin: results of a clinical trial.

The aim of this study was to demonstrate that modification of the cellular redox-equilibrium occurs as a consequence of antioxidant nutrients intake (carotenoids, vitamine E and vitamine C) and that these nutrients play a role in the pigmentation of the skin without any UV exposure. We conducted a randomized, double-blind study in 20 healthy subjects to evaluate and to compare the efficacy of two mixtures of dietary antioxidants with regard to direct determination of melanin and carotenes by chromametry at selected skin sites and multiple reflection spectrometry from a 1 cm2 region of skin of different parts of the body. Efficacy was assessed by a significant improvement of these parameters, in comparison with measurements performed on the day of randomization, before dietary supplement intake. The formulations per capsule of study dietary supplements are: 13 mg of beta-carotene, 2 mg of lycopene, 5 mg of vitamine E and 30 mg of vitamine C (B13/L2) or 3 mg of beta-carotene, 3 mg of lycopene, 5 mg of vitamine E and 30 mg of vitamine C (B3/L3). A 8-week B13/L2-supplementation lead to a detectable carotenodermia whereas the B3/L3-supplementation not. Signicative increase of melanin concentrations in skin were found after 4, 5, 6 and 8 weeks of dietary antioxidant intake in both groups (p < 0.05). These results are discussed with regard to the redox control theory of melanocytes which regulates the tyrosinase activity.

Adult↗
PubMed1996

Pharmacokinetics of superoxide dismutase in rats after oral administration.

The kinetic behaviour of bovine erythrocyte Cu-Zn SOD was investigated in Sprague Dawley male rats after subcutaneous and oral administrations of doses ranging from 0 center dot 5 to 20 mg kg-1. Studies have been carried out with SOD and SOD encapsulated into liposomes containing or not containing ceramides. The maximum concentration (Cmax) in blood cell pellets ranged from 8 center dot 65 to 11 center dot 03 U/mg haemoglobin (Hb) after subcutaneous injection, and from 4 center dot 48 to 8 center dot 23 U/mg Hb after oral administration. The maximum concentrations were reached in 5 h (t max) for the two routes. Comparison between the areas under the curves (AUCs) obtained after subcutaneous and oral administration allowed the calculation of relative bioavailability (F'). The maximum bioavailability after oral administration was 14% for free SOD, 22% for SOD encapsulated into liposomes, and 57% when ceramides were added to liposomes. Poor SOD bioavailability was enhanced by liposome encapsulation, and ceramide addition seemed to be beneficial for oral encapsulated SOD administration.

Administration, Oral↗
PubMed1996

Kinetic evaluation of nitric oxide production in pleural exudate after induction of two inflammatory reactions in the rat.

NO generation in the course of two acute, non immune, inflammatory reactions (pleurisy induced by rat isologous serum and carrageenan) was assessed by means of nitrite measurement in pleural exudate from 0.5 to 24 h. NO release varied time-dependently, similarly for the two inflammatory reactions. A first, but transient, peak was reached in 30 min while a second peak, more sustained, began at the fourth hour and was maximum at the tenth. Kinetic evolution of NO release was consistent with activation, in a first step, of a constitutive NO synthase probably from endothelial origin (inhibited by 2-Methyl-2-Thiopseudourea sulfate but not by dexamethasone) and with activation, in a second wave, of inducible NOS from endothelial and exudative cells. NO release was potentiated by administration per os of L-Arginine and seems to be involved in the evolution of acute inflammatory reactions and oxygen metabolite production.

Animals↗
PubMed1995

Effect of encapsulation on the anti-inflammatory properties of superoxide dismutase after oral administration.

Anti-inflammatory properties of free superoxide dismutase and superoxide dismutase encapsulated into liposomes, with or without ceramides, have been investigated. Two models were investigated: carrageenan paw oedema and pleurisy. Animals were fed by repeated doses, twice daily from day 1 until day 4. Evaluation consisted of measurement of paw oedema volume with determination of prostaglandin E2, thromboxane B2 and 6-keto-prostaglandin F1 alpha levels. Polymorphonuclear oxidative metabolism was evaluated by measurement of superoxide anion production. Levels of superoxide dismutase were determined in cells and pleural exudates. Higher anti-inflammatory effects were obtained after eight administrations of encapsulated forms (0.5 mg/kg) whereas free superoxide dismutase have shown no effects. Ceramides enhanced the results obtained.

Administration, Oral↗
PubMed1995

Increase of singlet oxygen protection of erythrocytes by vitamin E, vitamin C, and beta carotene intakes.

Substantial evidence supports the theory that free radicals, especially oxygen radicals, are involved in the process of aging. The human organisms have two ways to fight them: an enzymatic way with enzymatic intervention like superoxide dismutase, catalase... and a chemical way with the intervention of scavengers such as vitamins, cysteine, methionine, gluthatione... The aim of this work was to determine that an intakes of vitamins association: vitamin E, vitamin C and beta carotene induce an increase of singlet oxygen protection of erythrocytes' subjects. The method was based on the haemolytic effect of singlet oxygen which is generated by irradiation of hematoporphyrine at 365 nm, in 22 p. cent suspension of erythrocytes' subjects. Results show that a supply of beta carotene (15 or 30 mg/day), vitamin E (15 mg/day) and vitamin C (30 mg/day) involves an increase of singlet oxygen protection of erythrocytes of subjects. This protection appears very quickly after 15 days of treatment.

Administration, Oral↗
PubMed1995

[Effect of the liposolubility of free radical scavengers on the production of antigen P24 from a HIV infected monocytic cell line].

A large body of evidence indicates that AIDS may be the consequence of a virus-induced antioxidant deficiency and implicates reactive oxygen species (ROS) in the pathogenesis of HIV infection. The high level of antigenic acid and cytokines activities in AIDS results in the production of superoxides (O2-), hydrogen peroxide (H202) and hydroxyl radicals (OH). HIV-infected T cells display low levels of SOD, catalase, thioredoxin and glutatione peroxidase rendering them susceptible to undergo apoptosis. Induction of NF kappa B and HIV replication are at least in part dependent on reactive oxygen intermediates. We examined the protective effects of two antioxidants. Ferulic Acid (FA) and Ethyl Ferulate (EF) at 1, 5, 10, 10 microM on the TNF induced HIV activation in the chronically infected promonocytic U1 cell line. FA and EF at 5 microM elicit a marked decrease of HIV p24 release. HIV inhibition was greater after pretreatment with EF than with FA. At these concentrations, no cytotoxicity was observed. When SOD (100 UI) was combined with EF and FA no more inhibition was observed. But when SOD was added alone, it induced a marked inhibition (30%). This class of drugs may present potential interest as antiviral agents or as adjuvant therapy in AIDS.

Antioxidants↗
PubMed1995

[Evaluation of the antiradical protector effect of multifermented milk serum with reiterated dosage in rats].

Epidemiological and experimental studies suggest that dietary milk products may exert an inhibitory effect on the development of several types of tumors. Some recent experiments in rodents indicate that the antitumor activity of the dairy product is in the protein fraction and more specifically in the whey protein component of milk. It has been demonstrated that whey protein diets result in increased glutathione (GSH) concentration in a number of tissues, and that some of the beneficial effects of whey protein intake are abrogated by inhibition of GSH synthesis. Whey protein is particularly rich in substrates for GSH synthesis. It has been suggested that whey protein may be exerting its effect on carcinogenesis and VIH infection by enhancing GSH concentration. Lactoferrin, one of the proteins contained in whey has aise been studied in this way. It has been suggested that lactoferrin binding may play an important role in maintaining, optimal mononuclear phagocyte function, thus protecting adjacent tissue against phagocyte derived radicals. Moreover it has been demonstrated by one of us that the level of plasma lactoferrin were decreased in HIV-1 infected patients in relation to the progression of the disease. The aim of the present study is to evaluate in rat the reactive oxygen species, scavenger activities (ROSSA) of red blood cells (RBCs) with a multifermented whey (SK 344), by repeated doses during 16 days. This study has permitted to demonstrate in vivo that the SK 344 has an excellent ROSSA corresponding to a limitation of the lipoperoxidation of RBCs membranes by singlet oxygen and nitric oxide. We can conclude that whey protein, lactoferrin and multifermented whey are good candidates as dietary inhibitors of the oxidative stress and should be considered as potential medicinal foods in various pathologies as HIV infection and cancer.

Amidines↗
PubMed1991

Simultaneous determination of water-soluble vitamins by over-pressure layer chromatography and photodensitometric detection.

An over-pressure layer chromatographic procedure with photodensitometric detection for the simultaneous determination of water-soluble vitamins in multivitamin pharmaceutical preparations was developed and evaluated. The method uses high-performance TLC (HPTLC) plates with silica gel as the thin-layer, and an n-butanol:pyridine:water mixture (50:35:15, v/v/v) as mobile phase at a rate of 0.25 mL/min for baseline separation. The quantitation was carried out without derivatization (vitamin B1, vitamin B2, vitamin B6, folic acid, nicotinamide, vitamin C) or after spraying ninhydrin reagent (calcium pantothenate) or 4-dimethylaminocinnamaldehyde (vitamin B12, biotin). This was applied to the analysis of multivitamin solutions. Satisfactory relative standard deviations and good recovery were obtained for all the vitamins examined. It was concluded that this method is fast, accurate, specific, and suitable for routine quality control use.

Absorptiometry, Photon↗
PubMed1988

Chemical stability of bupivacaine in pH-adjusted solutions.

Recent clinical studies have suggested that alkalinization of bupivacaine may shorten the time to onset and lengthen its duration of action. However, addition of sodium bicarbonate to commercially manufactured bupivacaine can rapidly produce precipitation. This study was performed to study the stability and precipitation of bupivacaine solutions 0.25% and 0.50% with and without epinephrine 1:200,000 after alkalinization. The results indicate that alkalinization does not increase precipitation above recommended limits and that the concentration of bupivacaine in solutions is maintained at least 6 h after alkalinization.

Bupivacaine↗
PubMed1988

Chemical stability of lignocaine (lidocaine) and adrenalin (epinephrine) in pH-adjusted parenteral solutions.

Recent clinical studies have shown that alkalinizing lignocaine (lidocaine) solutions is an effective way of shortening the time of onset and increasing the duration of anaesthesia. However, alkalinizing lignocaine solutions raises the problem of the stability of these preparations. Moreover, the adrenalin usually associated with it is unstable in alkalinized solutions designed for peridural injection. This study was performed to define the range of pH over which lignocaine and adrenalin in commercial solution is stable. The results indicate that it is possible to alkalinize lignocaine solutions and that the solutions prepared are stable for at least 6 h.

Drug Combinations↗
PubMed1988

Influence of the surface area of different dialysis membranes on granulocyte adherence and superoxide generation.

Granulocyte adherence and superoxide anion generation were investigated in vitro in the presence of dialysis membrane fragments incubated with normal human polymorphonuclear cells. Dialysis membranes made from cellulosic material or non-cellulosic material like polyacrylonitrile, polymethylmetacrylate, and polysulfone were tested. The membrane surface area varied (1-5 cm2) while the membrane surface/polymorphonuclear cells ratio was maintained constant (2 X 10(6) cells/cm2). The contact of polymorphonuclear cells with increasing membrane surface area generated a significant decrease of superoxide anion generation (5-80% of inhibition) and produced an increase of granulocyte adherence (5-52%). This phenomenon was observed for all the tested membranes, whether opsonized zymosan or phorbol myristate acetate were used as stimuli. Similar results were obtained after washing the dialysis membrane or when polymorphonuclear cells were suspended in homologous serum. In vitro exposure of granulocytes to cellulosic or non-cellulosic dialysis membranes caused a surface-area dependent modification of polymorphonuclear functions.

Cell Adhesion↗