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Biomedical subjects

F Roux

Publications and source records attributed to F Roux.

At least 73 records · Page 4Linked to original sources
PubMed1993

Nitric oxide and endothelin secretion by brain microvessel endothelial cells: regulation by cyclic nucleotides.

Endothelin (ET)-1 was originally characterized as a potent vasoconstrictor peptide secreted by vascular endothelial cells. It possesses a wide range of biological activities within the cardiovascular system and in other organs, including the brain. Also secreted by endothelial cells, nitric oxide (NO), has recently been identified as a relaxing factor, as well as a pleiotropic mediator, second messenger, immune defence molecule, and neurotransmitter. Most of the data concerning the secretion of these two agents in vitro has been collected from studies on macrovascular endothelial cells. Given the remarkable heterogeneity of endothelia in terms of morphology and function, we have analyzed the ability of brain microvessel endothelial cells in vitro to release ET-1 and NO, which, at the level of the blood-brain barrier, have perivascular astrocytes as potential targets. The present study was performed with immortalized rat brain microvessel endothelial cells, which display in culture a non transformed phenotype. Our data demonstrate that: (1) these cells release NO when induced by IFN gamma and TNF alpha, (2) they constitutively secrete ET-1, and (3) cAMP potentiates the cytokine-induced NO release and exerts a biphasic regulation on ET-1 secretion: micromolar concentrations of 8-Br-cAMP inhibit and higher doses stimulate ET-1 secretion. This stimulation is blocked by EGTA and the calmodulin antagonist W7, but not by protein kinase C inhibitors, suggesting the involvement of the calmodulin branch of the calcium messenger system. These results suggest that cerebral microvessel endothelial cells may participate in vivo to the regulation of glial activity in the brain through the release of NO and ET-1.

Amino Acid Oxidoreductases↗
PubMed1990

[Study of two goitrous endemic areas in Niger: Belley-Koira and Tiguey-Tallawal].

The present work reports the clinical and laboratory findings in two endemic areas in Niger: Tiguey-Tallawal and Belley-Koira. The goitrous subjects (n = 293), mainly children and adolescents, have clinical evidence of euthyroidism but with biological criteria of hypothyroidism in 25% of cases as shown by the decrease of the total serum T4 and the increase of serum TSH. Iodine deficiency intake evaluated by the determination of urinary iodine in single urine specimens is the permissive and main factor for goiter endemicity = 14 +/- 7 micrograms/l in Belley-Koira (n = 99), 26 +/- 23 micrograms/l in Tiguey (n = 155) and 25 +/- 19 micrograms/l in Tallawal (n = 95). The single intramuscular injection of iodized oil (240 mg of iodine) constitutes an extremely effective way of correcting iodine deficiency: decrease of volume or disappearance of goiter among 291 subjects out of 362 i.e. 80%, twelve months after the injection. The diffuse goiter, more numerous (n = 270) than nodular goiter (n = 92) are corrected with more efficiency (85% versus 50%). We also noted that non goitrous subjects living in these two endemic areas show a severe iodine deficiency (urinary iodine: 33 +/- 18 mu/l; n = 70 = 76) while those living in non endemic areas present a moderate or a low iodine deficiency, respectively in Niamey (urinary iodine: 48 +/- 36 micrograms/l; n = 200) and in Tamou (urinary iodine: 80 +/- 29 micrograms/l; n = 69). Severe, moderate and low iodine deficiency seem to be correlated with nutritional habits: mil in endemic areas, mil and meat in Niamey and mil, meat, milk and fish in Tamou. The nutriments eaten in Niger have a low iodine level except ewe milk: salt (270 to 7100 micrograms/kg), woman milk (40 +/- 21 micrograms/l) cow milk (22 micrograms/l) goat milk (50 micrograms/l), ewe milk (294 micrograms/l). Salt consumption, evaluated by the determination of urinary chloride, is adequate. Prophylaxis by iodinated salt should be well accepted. No other factors than iodine deficiency in the etiology of endemic goiter, mainly nutritional (goitrogens or protein-calorie malnutrition) can be evoked to explain clinical and biochemical discrepancies between subjects living in the same morbid territory.

Adolescent↗
PubMed1989

Purified rat brain microvessels exhibit both acid and neutral sphingomyelinase activities.

Purified rat brain microvessels have been shown to hydrolyze radiolabeled sphingomyelin by means of two different enzyme systems. Enzymatic activity was detected at pH 7.4 and was strongly stimulated by magnesium or manganese and inhibited by calcium. Activity at pH 5.1 could also be found and was not dependent on any of these cations. At neutral pH and in the presence of magnesium, the rate of sphingomyelin hydrolysis did not exhibit a linear relationship with protein concentration. In contrast, increasing the protein concentration from 0.05 to 0.5 mg/ml resulted in a constant increase of sphingomyelin hydrolysis at pH 5.1. Kinetic parameters of both neutral and acid activities have been determined and were similar in magnitude to values reported previously for neural sphingomyelinases. This work demonstrates the occurrence of a neutral sphingomyelinase activity in purified rat brain microvessels, an observation raising the question of its role at the level of the blood-brain interface.

Animals↗
PubMed1988

[Coral: a new procedure for cranio-facial reconstruction].

Twenty two cranio-facial reconstructions were performed utilizing madreporic coral graft, genera porites. Long-term tolerance was excellent. Surgical technique is described and coral properties are analyzed. Coral grafts used for anterior skull base reconstruction were partly reossified without any infectious complication.

Biocompatible Materials↗
PubMed1987

Evidence for an alanine, serine, and cysteine system of transport in isolated brain capillaries.

Brain capillaries isolated from 2-month-old male and female Sprague-Dawley rats were used to study the transport of neutral amino acids. The uptake of alanine, leucine, and alpha-methylaminoisobutyric acid (MeAIB) was a linear function of time for the first minute of incubation. Based on these observations, an incubation time of 1 min was used to measure transport activities. The intracellular water volume of the isolated capillaries was 2.2 microliters/mg protein. This value was significantly lower (1.8 microliter/mg protein) when measured in the absence of sodium. L-Alanine, L-serine, and L-cysteine were taken up from the abluminal surface of brain capillaries by a sodium- and energy-dependent, carrier-mediated system. This uptake, for the most part, was not inhibited by MeAIB. System ASC (alanine-serine-cysteine) appeared to be of primary importance for the transport of these amino acids in isolated brain capillaries. The apparent Km and Vmax values for L-alanine uptake by ASC transport, based on the Hofstee plot presentation, were 1.3 mM and 0.975 nmol/microliter water content/min, respectively. The results also indicate that the transport of MeAIB and 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH) was limited to the sodium-dependent system A (alanine) and the sodium-independent system L (leucine), respectively.

Alanine↗
PubMed1985

The synthesis of lipids from [1-14C]acetate by isolated rat brain capillaries.

Lipid biosynthesis was investigated in isolated cerebral microvessels obtained from adult Sprague-Dawley rats using [1-14C]acetate as precursor. All lipid classes were labelled by [1-14C]acetate. Neutral lipids incorporated about 50% of radiolabelled acetate, among which free fatty acids and triglycerids showed the highest level of incorporation. Moreover, about 4% of radioactivity was found in cholesterol fraction. In phospholipid fraction, phosphatidylcholine and phosphatidylethanolamine were the main radiolabelled phospholipids. [1-14C]acetate was also incorporated into sulphatides and cerebrosides. The presence of bovine serum albumin in incubation medium modified the percentage of incorporation in different lipid fractions.

Acetates↗
PubMed1985

[Mucoceles of the sphenoid sinus and their ophthalmological manifestations].

The authors describe two cases of sphenoïd sinus mucoceles, the first with a chiasmatic syndrome and the second with an oculomotor paralysis, and compare these cases with those described in the litterature. This rare benign tumor is revealed by ophthalmological complications which result from compression of adjacent structures. The main clinical findings are pain, decrease in visual acuity, proptosis, and diplopia. Plain X rays and pluridirectional tomographies are usually sufficient to make the diagnosis but CT scan is the procedure of choice for defining the extent of the lesion and thus assuring an appropriate surgical approach. The CT scan findings have been reviewed. Early and correct diagnosis is important to prevent permanent visual loss by optic nerve atrophy.

Adult↗
PubMed1985

[Serum carbohydrate 19-9 Tm and bronchial cancer. Comparative study with another tumor marker, carcinoembryonic antigen].

Carbohydrate antigen 19-9 Tm (CA 19-9 Tm) level was measured in 3 groups of sera: 138 control subjects affected by bronchogenic no malignant diseases, 117 subjects with primary bronchogenic carcinoma, 43 with pulmonary metastasis of different cancers. Serum level CA 19-9 Tm was compared with serum level CEA. Control subjects bring us to state the discrimination standard between bronchogenic carcinoma and no carcinoma to 40 U/ml of CA 19-9 Tm. In primary bronchogenic carcinoma, a simultaneous increase of the two markers was noted in some subjects whereas in others only one tumor marker was increased pulmonary metastasis are considered. In these two cases, CEA increases more often in serum of subjects affected by adenocarcinomas CA 19-9 Tm and CEA are thus two different tumor associated markers.

Antibodies, Monoclonal↗
PubMed1983

[Enlarged transbasal approach by mobilization of the medial fronto-orbital ridge].

Tumors involving the base of the skull are best approached by the transbasal route as described by Derome. However this approach can be improved by mobilization of the medial part of the supra-orbital ridge according to the technical principles used in treatment of craniosynostosis. This allows a wide exposure of the ethmoido-sphenoidal area with minimal retraction of the frontal lobes. The axis of working becomes parallel and even inferior to the plane of the cribriform plate and gives a better access to the upper part of the clivus. Rhinologic complementary approach (rhinoseptal or transfacial) can be associated with this technique. However a more anterior part of the nasal mucosae is exposed by this procedure: one can control the mucosae in front of the tumor and avoid a complementary rhinoseptal route. This simple technical trick has been used in seven cases with satisfactory results.

Humans↗
PubMed1982

Effects of methyl mercury and triethyllead on Na+K+ATPase and pyruvate dehydrogenase activities in glioma C6 cells.

The effect of methyl mercury (MeHg) and triethyllead (Et3Pb) on the membrane bound SH-enzymes Na+K+ATPase and pyruvate dehydrogenase (PDH) was studied in relation to the effect on the galactosyl ceramide sulfotransferase (CST) and to morphological changes in glioma C6 cells. Two-day-old cultures were incubated for 1 or 20 hrs with 5-30 microgram MeHgC1 and 2-8 microgram Et3PbC1/mg cell protein. The results show that both compounds induced morphological changes and a reduction of CST activity at growth inhibitory concentrations. A less marked reduction of Na+K+ATPase was induced with increasing exposure time only in MeHgC1 treated cultures, and PDH activity was not affected by either of the compounds under the experimental conditions. Thus, an interference with Na+K+ATPase and PDH activities do not appear to be a primary effect of MeHg and Et3Pb intoxication.

Animals↗
PubMed1982

[Comparative study between two methods of total and specific IgE assays : radioimmunoassay (RIA) and enzymoimmunoassay (EIA) (author's transl)].

This study shows : concerning total IgE : a good correlation between the results (r = 0,98) and a regression line EIA = f(RIA), y = 0,98 X + 11; concerning specific IgE, most of the dissociations found seemed to be related only to the semi-quantitative definition of classes. Thus it seems that the assay of total as well as specific IgE may be done in good conditions by both methods.

Immunoenzyme Techniques↗
PubMed1981

Binding of 99mTc plasminogen on fibrin.

Binding of plasminogen to fibrin was studied in vitro and in vivo using 99mTc Glu- and Lys-plasminogen. Binding of Glu-plasminogen on the clot was not observed in vitro, and in vivo in the dog. Conversely, the binding of Lys-plasminogen to fibrin displays a linear relationship to the concentration of Lys-plasminogen, up to doses exceeding equimolarity; thus suggesting the existence of several Lys-plasminogen binding sites on fibrin. Binding levels were identical, regardless of whether plasminogen was incubated in normal plasma or in plasma devoid of antiplasmin. In the dog, Lys-plasminogen bound specifically to the clot, however, clot sites could not be localized by scintigraphy in the dog or in man.

Animals↗