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Biomedical subjects

O Guillard

Publications and source records attributed to O Guillard.

At least 37 records · Page 2Linked to original sources
PubMed1992

Role of aluminium in skin reactions after diphtheria-tetanus-pertussis-poliomyelitis vaccination: an experimental study in rabbits.

The occurrence of subcutaneous nodules at the injection site is one of the complications of diphtheria-tetanus-pertussis-poliomyelitis vaccination, but the causes and mechanisms involved are still poorly understood. An experimental study in the New Zealand rabbit enabled us to determine the frequency of occurrence of these nodules, how long they persist and the histopathologic features of the cells involved. Aluminium (Al) assays by electrothermal atomic absorption spectrometry allowed us to study concentrations both in nodules and the organism (serum, normal skin). The results show an absence of Al diffusion outside nodules, a correlation between infiltrate intensity and Al concentration in nodules and modifications in the histological constituents of nodule cells. The histological picture indicates a foreign body reaction to Al. All these data underscore the role of Al in the formation of early postvaccinal nodules at the injection site.

Aluminum↗
PubMed1990

Mechanism of Alzheimer's disease: arguments for a neurotransmitter-aluminium complex implication.

The authors are convinced that in Alzheimer's disease, as in Down's syndrome and Guam-Parkinson dementia, one may find an alteration in blood brain barrier transfer and a resultant imbalance in mineral metabolism. Metals, such as aluminium, which in vivo yield stable complexes with aspartic and glutamic acids act as previously been clearly shown with glutamic acid; they cross the blood brain barrier, and are deposited in the brain. The authors explain how amyloid protein or neurofibrillary tangles could well be produced by aluminium complex formation. Within the brain, in the form precisely of aluminium complex, L-glutamic acid is consequently unable to detoxify ammonia from neurons and to produce L-glutamin. Accumulation of ammonia is subsequently responsible for the neuronal death, affecting each and every neurotransmitter system.

Aluminum↗
PubMed1990

Aluminum transfer as glutamate complex through blood-brain barrier. Possible implication in dialysis encephalopathy.

In vitro distribution of aluminium between plasma and erythrocytes has been studied in the presence of variable amounts of sodium L-glutamate. With a red blood cell suspension in isotonic sodium chloride, aluminium remains confined in erythrocytes even when the sodium L-glutamate concentration increases in the medium. Aluminium initially present in plasma penetrates red blood cells when sodium L-glutamate increases in whole blood, showing that this metal is able in vitro to cross the erythrocyte membrane as glutamate complex. In vivo experiments with male Wistar rats prove that aluminium is also able to pass the blood--brain barrier as glutamate complex and deposit in the brain cortex.

Aluminum↗
PubMed1990

Severe selective magnesium malabsorption: tests of tolerance of oral magnesium supplements.

Since his birth, we have been monitoring a 12-year-old boy suffering from selective severe magnesium malabsorption. Our essential problem is to prepare a form of galena with acceptable taste, tolerated by the digestive tract and well absorbed; also, the carrier compound must not cause short- or long-term side effects. An additional factor is the steadily increasing need for magnesium from 1 mmol/kg.d at 1 year to 14 mmol/kg.d at present age (345 mg/kg.d). The galena forms currently on sale were, with the exception of lactate and pyrollidone carboxylate, immediately rejected since they contain insufficient Mg2+. Following short trials resulting in diarrhoea, the other two preparations were also rejected. We then constituted - and also abandoned - our own galena compounds: aspartate (bitterness), aspartate + glycerophosphate (GLP) (bitterness), glutamate + GLP ('Chinese restaurant syndrome' and fear of the long term toxic effect of the glutamate), gluconate (excessive volume: 11/1 proportion with Mg2+). A recent test featuring GLP of Mg 40 g + cocoa butter 40 g + cocoa 10 g, brought about vomiting and diarrhoea, and was not adequately absorbed. The best tolerated formula is: Mg GLP 21.33 g; saccharose 6 g; aspartam 1 g; gelatin 0.5 g; citric acid, conserving agent, fruity aroma; water: qs 100 g. Such composition yields a caramel cream absorbed in five small portions, at a daily quantity of 375 g (80 g GLP Mg, 10 g Mg2+). Vitamin B6, which promotes intestinal absorption of magnesium, must be given separately in tablet form at a dose of 1 g/d, since it causes nausea if it is included in the Mg preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1989

In vitro and in vivo effect of mercury, lead and cadmium on the generation of chemiluminescence by human whole blood.

A method based on the use of the luminogenic substance, luminol, was developed for measuring the respiratory burst induced by phorbolmyristate acetate in 4 microliters of human whole blood. In vitro, the three cations, Hg2+, Pb2+ and Cd2+, inhibit the peak luminescence response at concentrations higher than those usually found in blood of subjects exposed to these metals. Cadmium metallothionein, however, in a concentration range similar to that found in whole blood of workers exposed to cadmium strikingly reduces the respiratory oxidative burst. In workers exposed to inorganic lead or mercury vapour, no reduction of the chemiluminescence response of whole blood was observed while a slight but statistically significant reduction was found in whole blood from cadmium exposed workers. If a similar effect occurs in lung macrophages, it might decrease the respiratory tract resistance to infection.

Adult↗
PubMed1988

[Levels of manganese in biological media: value, samplings, physiopathological variations. Bibliographic review].

The great diversity of methods for manganese analysis in biological materials (serum, plasma, whole blood, urine, spinal fluid and hair) reveals the difficulty in measuring extremely small quantities of this element. An examination of these methods demonstrate that the most used one is flameless atomic absorption spectrometry. This review offers a comparison of the different instrument settings. Authors' recommendations for the collecting of samples are reported in detail. A description of the preliminary steps, the handling of the specimen samples, the preparation of the standards, procedures used, analytical criteria and perturbations is also included. Normal values and their physiological and pathological variations are also described.

Body Fluids↗
PubMed1988

[Comparative effects of pindolol and atenolol on blood pressure and lipids in mild to moderate arterial hypertension].

Twenty-one patients with mild or moderate hypertension were randomised to receive either Atenolol 100 mg (N = 10) or Pindolol 15 mg (N = 11) in a once daily dosage over a two month period. The effects of these two betablockers on the blood pressure and plasma lipid profile were studied. Special attention was paid to the methodology: obese patients (30% over theoretical weight derived from the Lorenz formula) and those with pre-treatment triglyceride levels higher than 1.82 mmol/l were excluded because of the well documented biological instability of such patients. The selected patients were given placebo for two weeks. At the end of the placebo period those subjects whose body weight, total cholesterol, apolipoproteins or triglycerides had varied by more than 10%, 15% and 30% respectively, were also excluded from the study. At the end of the 60 days active treatment period, a comparable fall in the blood pressure was observed in both groups and there was no significant difference in the biological parameters as compared with pre-treatment values. In addition, the cardiovascular risk, evaluated by the B/A1 apolipoprotein ratio, increased in only one patient in the group receiving Atenolol and one patient receiving Pindolol.

Atenolol↗
PubMed1988

Determination of manganese in biological materials by electrothermal atomic absorption spectrometry: a review.

The great diversity of methods for measuring manganese in biological materials (serum, plasma, whole blood, urine, spinal fluid, and hair) reflects the difficulty in measuring extremely small quantities of this element. Detailed examination of these methods demonstrates that the one most used is flameless atomic absorption spectrometry. In this review we report the different instrument settings for wavelength, slit width, protection gases, graphite furnaces, type of background correction, amounts measured, and thermal programs. We give detailed recommendations by various authors for collecting samples. A thorough description of the preliminary steps and the handling of the specimen samples is also included: direct determination with or without dilution, addition of a matrix modifier or determination after ashing, with or without chelation-extraction steps. The preparation of the standards, procedures used, analytical criteria (accuracy, precision, specificity, detection limit, linearity), problems (interferences, matrix effects), and reference values and their physiological variations are also described. We give a consensus of recommendations concerning the choice of a method.

Female↗
PubMed1988

An international quality-assessment program for measurement of aluminum in human plasma: a progress report.

In view of the increasing interest in measurement of aluminum in plasma of hemodialysis patients and the analytical difficulties, which may lead to false clinical interpretations, we organized an international interlaboratory quality-control program that has operated since 1983. The results obtained after four years (72 participants) demonstrate a lessened discrepancy of the results. This program allowed some laboratories to improve their results and even to solve some of their analytical problems. This surveillance will be continued and extended to include the analysis of dialysis fluids.

Aluminum↗
PubMed1987

Copper-induced lipid peroxidation and hemolysis in whole blood: evidence for a lack of correlation.

In order to establish a possible relationship between hemolytic and peroxidant activities of copper ions, lipid peroxidation was studied in plasma and whole blood incubated for 24 h with different concentrations of copper. The lipid peroxidation was investigated by the determination of thiobarbituric acid-reactive species, conjugated dienes and fluorescent lipid chromophores. The copper-induced lipoperoxidation was clearly demonstrated in plasma incubated with high concentrations of copper (12.10(-4) and 20.10(-4) M); in whole blood, all the lipoperoxidation products were increased in the plasma, while the fluorescent lipid chromophores remained unchanged in red cells. With a copper concentration similar to that found in acute copper intoxication (4.10(-4) M) no lipoperoxidation was observed and yet hemolysis occurred, reduced glutathione (GSH) decreased dramatically and methemoglobin (MetHb) increased. From these results, we assume that, despite its prooxidant activity and its capacity to produce lipoperoxidation, it has not been proven that copper ions at pathophysiological concentrations induce hemolysis by an oxidative mechanism.

Adult↗
PubMed1987

Comparison of the anti-inflammatory activity of sodium acexamate and zinc acexamate in healing skin wounds in rabbits.

After obtaining an abscess on the inner thigh of rabbits, the resulting inflammatory area was treated with sodium acexamate and zinc acexamate (0.5 ml s.c. of a 7% w/v solution). All animals received labeled leukocytes (111In, 1 mCi, i.v.). The hyperfixation was measured by comparing the inflammatory areas. In the group treated with zinc acexamate, the regression of inflammation was highly significant (p less than 0.001) in comparison with the other groups. These results emphasize the importance of combining zinc with acexamic acid for healing skin wounds.

Aminocaproates↗
PubMed1986

[Assay of urinary iodides by specific electrodes: its value in dysthyroidism].

A simple and reliable electrochemical urinary iodides determination method, using a crystalline membrane specific electrode is proposed. Normal adult values are determined. Determinations performed on 74 patients with an excess iodine induced hyperthyroidism show that urinary iodides determination is a good clinical evolution marker.

Electrodes↗
PubMed1985

Effects of cyclic (nocturnal) total parenteral nutrition and continuous enteral nutrition on circadian rhythms of blood lipids, lipoproteins and apolipoproteins in humans.

The aim of the present study was to investigate the occurrence and characteristics (acrophase, amplitude) of circadian rhythms of serum total cholesterol, free-fatty acids (FFA), triglycerides, lipoproteins (HDL-, LDL-, and VLDL-cholesterol), apolipoproteins A and B, glucose and total proteins in hospitalized patients fed with 12 h nocturnal total parenteral nutrition (TPN) (from 8 PM to 8 AM) including lipids, patients fed with continuous enteral nutrition over 24 h daily spans, and patients eating 3 meals a day serving as controls. All the subjects were synchronized with diurnal activity and nocturnal rest in the hospital routine. The results showed the following: 1) circadian rhythms of total cholesterol, triglycerides, FFA, HDL-, LDL-cholesterol, apolipoprotein A and total proteins were detected in both TPN patients and controls, rhythms of apolipoprotein B and glucose in TPN patients only; in enteral nutrition patients, rhythms were detected for total proteins, glucose and triglycerides only; 2) a significant shift in triglyceride and FFA acrophases was observed in TPN patients, as compared with controls; 3) 24 h mean of both triglyceride and cholesterol concentrations remained unchanged after one month, in both TPN and enteral nutrition patients. The present approach, by extending results of previous investigations, leads one to conclude that, on both a metabolic and a chronobiological basis, cyclic nocturnal TPN is well-tolerated.

Administration, Oral↗
PubMed1984

Evidence for the involvement of (Cu-ATP)2- in the inhibition of human erythrocyte (Ca2+ + Mg2+)-ATPase by copper.

The effects of copper on the activity of erythrocyte (Ca2+ + Mg2+)-ATPase have been tested on membranes stripped of endogenous calmodulin or recombined with purified calmodulin. The interactions of copper with Ca2+, calmodulin and (Mg-ATP)2- were determined by kinetic studies. The most striking result is the potent competitive inhibition exerted by (Cu-ATP)2- against (Mg-ATP)2- (Ki = 2.8 microM), while free copper gives no characteristic inhibition. Our results also demonstrate that copper does not compete with calcium either on the enzyme or on calmodulin. The fixation of calmodulin on the enzyme is not altered in the presence of copper as shown by the fact that the dissociation constant remains unaffected. It may be speculated that (Cu-ATP)2- is the active form of copper, which could plausibly be at the origin of some of the pathological features of erythrocytes observed in conditions associated with excess copper.

Adenosine Triphosphate↗
PubMed1984

Comparative pharmacokinetics of [65Zn]zinc sulfate and [65Zn]zinc pantothenate injected intravenously in rabbits.

The pharmacokinetics of zinc sulfate were compared with those of a new zinc salt, pantothenate, in rabbits. Each salt was administered at a dosage of 3.3 microCi of zinc-65/kg of body weight. The measured pharmacokinetics of the two compounds responded to a two-compartment open model. The urinary elimination of the two salts was similar, as was their localization in the skin and fur, but zinc pantothenate was fixed by the liver to a lesser extent than was zinc sulfate.

Animals↗
PubMed1984

Improved determination of manganese in hair by use of a mini-autoclave and flameless atomic absorption spectrometry with Zeeman background correction: an evaluation in unexposed subjects.

Motivated by the relatively wide range of values published hitherto, we offer a new, reliable method for determination of manganese in hair from unexposed human subjects. By using a mini-autoclave, we have developed a method that obviates loss of manganese during digestion and, thanks to use of a Teflon receptacle and rigorous methodology, contamination has been minimized. We used Zeeman flameless atomic absorption spectrometry, with the method of standard additions, for quantification. Within-run CVs for concentrations of Mn of 0.26 and 0.28 microgram/g of dry hair were 3.63 and 3.93%; the day-to-day CV for a Mn concentration of 0.29 microgram/g of dry hair was 5.84%. Mean (+/- SD) analytical recovery of Mn added to samples of hair was 104% (+/- 9.2%). The mean concentration of Mn found in the hair of 15 healthy unexposed subjects was 0.26 (+/- 0.05) microgram/g dry weight. This sensitive, reproducible procedure is suitable for use in analysis for traces of Mn in hair.

Adult↗