Search PubMed⌕ Search

Biomedical subjects

J Alary

Publications and source records attributed to J Alary.

At least 37 records · Page 2Linked to original sources
PubMed1995

Interactions related to trace elements in parenteral nutrition.

Trace elements (TE) are now commonly added into the nutritive admixtures used in total parenteral nutrition (TPN) to prevent deficiencies which can be observed in patients undergoing long-term intravenous feeding. Although the needs in TE are not exactly known during a TPN, some of them must be considered as essential according to the results of studies dealing with general nutritional deficiencies. Among essential TE copper, iron and zinc are found at relatively high levels in organism. Chromium, manganese and selenium are also very important even though they are present at lower levels. In the case of a parenteral nutrition, the composition of the mixture is precisely defined and both digestion and absorption steps are shunted. Nevertheless, beneficial and/or negative physicochemical and metabolic interactions can occur between TE and the other nutrients. These interactions must be studied and taken into account because they can modify the bioavailability of the trace elements. In this article, our aim is to review the main recent bodies of knowledge which could be helpful to understand and prevent nutritional problems linked to these interactions during parenteral nutrition.

Animals↗
PubMed1995

Validation of a modified spectrophotometric method for the determination of nitrate in dry milk using 2-sec-butylphenol.

A rapid, simple and direct visible spectrophotometric method, based on the quantitative nitration of 2-sec-butylphenol in concentrated sulfuric acid, is described for the determination of nitrate in milk. The nitration product was extracted into toluene and the yellow nitrophenoxide compound formed in alkaline aqueous solution was determined at 418 nm. Carrez reagents were used for protein precipitation. Interference from lactose, chloride and nitrite ions and the effect of reagent concentration was controlled. The calibration graph was linear over the range 0.5-5 micrograms ml-1 NO3-; y = -0.0019 + 0.0681 x; r = 0.9997. The limits of detection and quantification were found to be 0.18 and 0.5 microgram ml-1 NO3-, respectively. The accuracy of the method did not depend on nitrate content in spiked milk. The mean recovery of the spiked milk was found to be 99.81% with the confidence limits of 0.67%, a relative standard deviation (RSDr) of 1.79% for repeatability and an RSDR value of 1.90% for reproducibility. Adequate agreement was found between results obtained by the nitration method and those of the French official reduction spectrophotometric reference method (AFNor). For the Indonesian dry (powdered) milk sample studied the nitrate levels were in the range 10.7-29.5 mg kg-1 NO3-.

Animals↗
PubMed1995

Vitamin intakes (A, E, C, carotenes) in a French institution: assessment by the duplicate-diet method.

Duplicate meals of those eaten by 14 healthy young males (25-35 years of age), usual hospital diets for breakfast, lunch, and dinner, were collected for 5 consecutive days and freeze-dried. Fat-soluble vitamin (alpha-, beta-, gamma-, and delta-tocopherols, retinol, alpha- and beta-carotenes) and vitamin C contents were analyzed. Duplicate meals presented a wide range in vitamin levels. Large individual day-to-day variations were observed. The median daily intakes (n =70) of retinol equivalent (0.31 mg/day) and tocopherol equivalent (3.48 mg/day) were low. Only one third of the meals could provide sufficient amounts of fat-soluble vitamins, whereas vitamin C intakes were adequate (87.4 mg/day). So, fat-soluble recommended intakes were not supplied for most of the subjects in this study.

Adult↗
PubMed1995

Effects of modulation of sulphation and glucuronidation on chlorpropham metabolism and cytotoxicity in isolated rat hepatocytes.

After modulation of sulphation and glucuronidation, the relationship between the changes in metabolism and cytotoxicity of chloropropham (CIPC), a widely used herbicide, was investigated in isolated rat hepatocyte suspensions. Under physiological conditions, CIPC had a cytolytic effect, modified membrane permeability and reduced intracellular ATP level. CIPC was metabolized by hepatocytes mainly into 4-OH chlorpropham sulphate (37%) and glucuronide conjugates (18%). Inhibition of sulphation, by omitting sulphate from the isolation and incubation media, did not affect the cytotoxicity of CIPC, since there was a 2.5-fold compensatory increase in 4-OH CIPC glucuronide. Inhibition of glucuronidation by adding 4 mM D-galactosamine in the incubation medium led to a 66% decrease of glucuronide conjugate and simultaneously to a 32% decrease of sulphate conjugate. In that case, concentrations of free 4-OH CIPC in both hepatocytes and incubation medium were markedly increased, while those of 3-chloroaniline and 3-chloroacetanilide were slightly modified and remained low. This alteration of metabolism was accompanied by modification of cell permeability and reduction in ATP synthesis. The cytolytic effect was due to CIPC itself, whereas the effect on energetic metabolism was attributed to a metabolite. Results demonstrated for the first time a partial inhibition of sulphation by D-galactosamine (4 mM), probably due to the effect of D-galactosamine on intracellular ATP levels.

Adenosine Triphosphate↗
PubMed1992

Mechanism of cadmium-decreased glucuronidation in the rat.

In isolated rat hepatocytes, cadmium (0-200 microM) decreased the overall glucuronidation of both isopropyl N-(3-chloro-4 hydroxyphenyl)carbamate (4-hydroxychlorpropham, 4-OHCIPC) and 4-nitrophenol in a concentration-dependent manner. In contrast, in native rat liver microsomes, glucuronidation of 4-OHCIPC was increased by cadmium through activation of microsomal 4-OHCIPC glucuronosyl transferase. In addition, in rat microsome incubations, the net amount of 4-OHCIPC glucuronide was also indirectly increased by cadmium through a reduction in the activity of beta-glucuronidase. As the effect of cadmium on the activity of 4-OHCIPC glucuronosyl transferase could not account for the decrease in glucuronide formation in intact hepatocytes, the influence of cadmium on the availability of UDP-glucuronic acid (UDPGA) was investigated further. In isolated rat hepatocytes, cadmium depleted the UDPGA content in a dose-dependent manner without a change in the UDP glucose (UDPG) content. Cadmium did not increase the breakdown of UDPGA by microsomal UDPGA pyrophosphatase but strongly decreased (30-66%) the synthesis of the cofactor in the cytosol by inhibiting UDP-glucose dehydrogenase (UDPGDH). Cadmium (10-50 microM) was found to inhibit the purified enzyme from bovine liver (EC 1.1.1.22) non-competitively. In vivo in the absence of a substrate undergoing glucuronidation, cadmium administration, 1.5 and 2.5 mg Cd/kg i.v., to normally fed rats resulted in a 15 and 30% decrease of hepatic UDPGA, respectively. However, in the liver, neither the NAD+/NADH ratio nor the UDPG content was significantly changed following cadmium treatment. Both in vitro and in vivo results support the conclusion that in intact cells the reduction in overall 4-OHCIPC glucuronidation caused by cadmium was due to a decrease in UDPGA availability which results from the inhibiting effect of cadmium on UDPGDH.

Animals↗
PubMed1989

Cadmium-induced alterations of chlorpropham metabolism in isolated rat hepatocytes.

In order to investigate the various steps of chlorpropham (CIPC) metabolism which could be influenced by cadmium, isolated rat hepatocytes were incubated in the presence of CIPC (0.1 mM) and of increasing Cd concentrations (0-180 microM). The results showed that Cd accumulation in hepatocytes was in good correlation to its concentration in the incubation medium. At 90 microM Cd, hydroxylation of CIPC was only slightly decreased by 30%, while CIPC hydrolysis into 3-chloraniline was unaffected by the presence of Cd. Accordingly, unchanged CIPC increased in hepatocytes. At 27 microM Cd, free 4-hydroxychlorpropham (4-OHCIPC) increased in the intracellular medium as a consequence of a strong suppression of both sulfation and glucuronidation which was related to the strong depletion of the intracellular ATP level under the combined influences of both cadmium and free 4-OHCIPC. Acetylation of 3-chloroaniline, which represents a minor pathway of CIPC metabolism, was already markedly suppressed (43%) with the lowest Cd concentration (27 microM). These in vitro results suggest that Phase II reactions are more sensitive to Cd than Phase I processes and that Cd enhanced the CIPC cytotoxicity as shown by alterations of the membrane integrity.

Acetylation↗
PubMed1989

Determination of 2-carboxy thiazolidine-4-carboxylic acid in biological fluids by ion-exchange chromatography.

A column ion-exchange chromatographic method for the determination of 2-carboxy thiazolidine-4-carboxylic acid (TDCA) in blood and urine is described. After elimination of endogenous thiols, alkaline hydrolysis of the compound yields cysteine which is determined spectrophotometrically. The described method is specific for intact TDCA. Using a 3-ml aliquot of sample it allows the linear determination of this hepatoprotective drug from 5 micrograms TDCA ml-1 with a detection limit of 3 micrograms ml-1. The method was applied to study the time course of plasma levels and urinary excretion. An in vitro metabolism study showed that TDCA has a potential as a cysteine donor for glutathione synthesis.

Animals↗
PubMed1988

Effects of varying dietary proteins on plasma lipids and rabbit platelet function.

The aim of this paper was to study the effect of dietary proteins on rabbit platelet aggregation induced by ADP, collagen and thrombin. In addition, blood coagulation tests (Stypven, Stypven cephalin and cephalin kaolin plasma clotting times) were performed on these rabbits fed semi-synthetic diets containing animal protein (casein) or vegetable proteins (walnut or soybean). As part of this study, total cholesterol, HDL cholesterol, phospholipid and triglyceride plasma levels were determined and platelet fatty acid composition was analysed. The results show that the addition of walnut meal in the diet decreases platelet aggregability and total plasma cholesterol. The relative effects of casein, soybean and walnut protein on platelet aggregability best correlated with the ratio of lysine to arginine in the protein and the ratio of HDL to LDL. An increase in the ratio C20:5 n-3/C20:4 n-6 in platelet fatty acids was also seen in walnut and soybean protein-fed animals, but the changes were greatest in soybean protein-fed animals while inhibition of platelet aggregation was greatest in walnut protein-fed animals.

Animals↗
PubMed1985

Determination of cobalt in forages by Zeeman electrothermal atomic absorption spectrophotometry without preliminary extraction.

A simple and rapid method, avoiding preliminary extraction, is described for the determination of Co in plant samples. The factors influencing the mineralization steps and the interference of major elements are investigated. The described method gives a recovery in the range 100-110%. Use of the standard addition method avoids interference from Ca and Fe. In the range 0.1-1 ppm (dry basis), Co can be determined with a precision of 5%. The detection limit of the method is 0.02 ppm of Co in forages.

Animal Feed↗
PubMed1983

[Not Available].

Determination of drugs in foods. In foods, drugs can come from different sources: animal therapeutics, zootechnical feed supplementation or human food additives. The possible consequences arising from the presence of drugs in food are considered. The quantitative determination of drugs in feeds or in human foods must fulfil various requirements, including specificity, sensitivity, accuracy and rapidity. Spectroscopic, electrochemical and chromatographic techniques are discussed. Some examples reported are ipronidazole, pyrimethamine, diethylstilboestrol, decoquinate and chloramphenicol. The need for quality assurance in analysis is also discussed.

English Abstract↗