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Biomedical subjects

B Fabre

Publications and source records attributed to B Fabre.

At least 19 recordsLinked to original sources
PubMed2006

Incorporation of phytosterols in human keratinocytes. Consequences on UVA-induced lipid peroxidation and calcium ionophore-induced prostaglandin release.

We have designed experimental conditions allowing the replacement of 50% of cholesterol of human keratinocytes (SVK14 line) with sitosterol or stigmasterol without affecting cellular viability. We have investigated the influence of incorporating phytosterol on the ultraviolet-A-induced formation of lipid-peroxidation products (thiobarbituric reactive substances (TBARS)) in these cells. Our results show that ultraviolet-A-induced lipid peroxidation depends on the nature of the phytosterol. Sitosterol induces a significant decrease (-30%) of TBARS relative to the control whereas stigmasterol markedly increases lipid peroxidation (+70%). We have also studied the effect of plant sterols on prostaglandin release by using the Ca(2+) ionophore A23187 as an in vitro model of the inflammation induced by UVA radiation. We show that in the presence of 50% of phytosterol (particularly stigmasterol), the release of prostaglandin (6-ketoPG(1alpha), PGE(2)) is increased compared to untreated cells. This pro-inflammatory effect of phytosterols is correlated with a loss of the regulation of the intracellular Ca(2+) concentration.

Calcium↗
PubMed2006

Human leukocyte antigens and susceptibility to tuberculosis: a meta-analysis of case-control studies.

OBJECTIVE: To evaluate the association between human leukocyte antigens (HLA) of the major histocompatibility complex (MHC) and thoracic tuberculosis (TB) in immunocompetent adults. DESIGN: We searched Medline, Pascal, Pascal Biomed and Francis databases (all years) with the terms 'tuberculosis' and 'HLA'. Case-control studies were included that reported frequencies for the full range of antigens analysed by serological methods in healthy controls and adult patients not treated with glucocorticoids or immunosuppressive drugs, human immunodeficiency virus status negative or not reported, no debilitating chronic disease, and with a diagnosis of thoracic TB based on microbiological or histological criteria. Two authors independently abstracted the data and resolved disagreements by consensus. RESULTS: We summarised 60 HLA antigens reported in at least four of 22 studies totalling 1988 patients and 2897 controls. A lower risk of thoracic TB was found in carriers of B13 (OR 0.64, 95% CI 0.50-0.81, P < 0.0001), DR3 (OR 0.72, 95% CI 0.59-0.89, P = 0.002), and DR7 antigens (OR 0.65, 95% CI 0.53-0.80, P < 0.0001). Carriers of DR8 were at higher risk for thoracic TB (OR 1.72, 95% CI 1.21-2.46, P = 0.003). For these antigens, we found no significant heterogeneity between samples or evidence of publication bias. The risk of thoracic TB tended to be higher in carriers of DR2 (OR 1.67, 95% CI 1.16-2.41, P = 0.006), but the results were not consistent between studies (P value for heterogeneity < 0.0001). CONCLUSION: Susceptibility to TB is modulated by class I and II HLA antigens. However, these results based on the serological determination of antigens require confirmation by DNA-based methods to precisely identify those alleles involved.

Case-Control Studies↗
PubMed2005

Pseudoxanthoma elasticum and nephrolithiasis.

We report the case of a 42-year-old man with pseudoxanthoma elasticum (PXE) and recurrent bilateral nephrolithiasis. Diagnosis of PXE was made by yellow papules on the neck and ophthalmologic angioid streaks. This diagnosis was confirmed by a skin biopsy (Von Kossa stain) and by genotyping analysis of ABCC6 (homozygous mutation R1138Q). Nephrolithiasis was recurrent and biological investigations showed hypophosphoraemia, hyperphosphaturia, hypercalciuria, normocalcaemia, normal serum parathyroid hormone value, high 1,25-dihydroxy vitamin D value and a renal calcium oxalate stone. ABCC6 encodes for MRP6, a multidrug resistant protein strongly expressed in the liver and kidney. The substrates of the MRP6 remain unknown. As PXE is characterized by calcification of elastic fibres and this patient presents important phosphocalcic anomalies, we discuss the possible implications of MRP6 in the phosphocalcic metabolism.

Adult↗
PubMed2004

Intense-laser-field ionization of molecular hydrogen in the tunneling regime and its effect on the vibrational excitation of H2+.

H2 molecules were ionized by Ti:sapphire (45 fs, 800 nm) and Nd-doped yttrium aluminum garnet lasers (6 ns, 1064 nm). The relative populations of the vibrational levels of the H+2 ions were determined and found to be concentrated in the lowest vibrational levels. Tunneling ionization calculations with exact field-modified potential curves reproduce the experimental results. The reason for the departure from conventional Franck-Condon-like distributions is the rapid variation of the ionization rate with internuclear distance.

Journal Article↗
PubMed2003

Trends in elective terminations of pregnancy between 1989 and 2000 in a French county (the Isère).

OBJECTIVES: This study was performed in order to provide a description of indications for induced elective terminations of pregnancy (ETOP), their characteristics (e.g. gestational age), and their evolution over time. DESIGN OF THE STUDY: This is an epidemiological study. The geographic area covered is the French county of 'Isère', which represents a mean of 14 000 births per year over the study period. MATERIALS AND METHODS: Data on ETOPs were collected actively from medical records by a register of childhood deficiencies and adverse perinatal events in this county. Between 1989 and 2000, 996 ETOPs were notified. RESULTS: Four main grounds for ETOPs were identified: (1) morphological anomalies with normal karyotype (39%), (2) chromosomal anomalies (35%), (3) other fetal grounds (16%), and (4) maternal indications (10%). Prevalence rates for the first two grounds increased significantly over the study period respectively from 2.0 to 2.9 and from 1.4 to 2.7 per 1000. Among the ETOPs carried out because of fetal indications, the percentage of late ETOPs (from 24 weeks of gestation) was 34.6%, and remained stable over the studied period. In some cases, a medical consensus was not reached with respect to indications for termination (sex chromosome anomalies, limb defects). We estimated the percentage of these cases as being 2.7% of the figure for fetal indications, without any variation in prevalence over the whole period (p = 0.59). The increasing number of ETOPs that occurred in the chromosomal aberrations group during the study period is thought to be due to an increase in diagnostic sensitivity. The increase that occurred in the morphological anomalies group is thought to be due both to an increase in sensitivity and to a widening of the field with respect to indications, some of which have an uncertain prognosis (e.g. agenesis of the corpus callosum). CONCLUSION: This study provides useful data for monitoring medical practice consistency within the field of prenatal diagnosis, and for the drive to keep medical practice within ethically acceptable limits.

Abortion, Induced↗
PubMed2003

[Trigeminal neuralgia presenting as a deep recurrent desmoplastic neurotropic melanoma of a lentigo maligna].

INTRODUCTION: Neurotropic melanoma is a particular anatomopathological form corresponding to dermal proliferation of desmoplastic cells of neuroid differentiation. We report a new case of neurotropic melanoma revealed by facial neuralgia. CASE REPORT: A 64 year-old man presented in 1996 with a lentigo maligna on the right cheek treated by complete excision. After 2 years of medical supervision, a pigmented lesion recurred leading to new surgical treatment. The histological examination of the total lesion showed intra-epidermal atypical melanocyte proliferation without dermal invasion. In 1999, right trigeminal neuralgia occurred without associated cutaneous change. Cranial MRI revealed an infiltration of the right trigeminal nerve. Endo-buccal surgery disclosed a black swelling of the trigeminal nerve. Histological examination and immunohistochemistry revealed a desmoplastic melanoma. DISCUSSION: Neurotropic melanoma with nerve invasion by malignant cells presenting as a trigeminal neuralgia is rare. Our case report underlined the depth of the neurotropic melanoma and the initial existence of a lentigo maligna without associated "neurotropic" melanoma.

Cranial Nerve Neoplasms↗
PubMed2002

Cadmium biosorption by free and immobilised microorganisms cultivated in a liquid soil extract medium: effects of Cd, pH and techniques of culture.

Instead of soil clean-up, a process not very technically and economically suited to agricultural soil contaminated by heavy metals (with a low concentration of heavy metals but highly or potentially highly contaminated surfaces), the control of the transfer of cadmium from the soil to the crops may well be a convenient method. We tested the bacterium ZAN-044, the actinomycete R27 and a basidiomycete Fomitopsis pinicola isolated for their ability to biosorb Cd, in order to inoculate agricultural soils afterwards. We then compared the cadmium biosorption by viable microbial cells which were free or immobilised in alginate beads and incubated in a soil extract liquid medium at various pH values (5, 6 and 7) and cadmium concentrations (1 and 10 mg/l). The Cd concentration in the medium had the most important effect on the percentage of Cd biosorbed by the microorganisms, but the culture mode (free or immobilised cells) was not a side effect. In the case of F. pinicola and the actinomycete R27, the percentage of Cd biosorbed by free cells did not decrease when the Cd concentration in the medium increased (6-42% at the lowest Cd concentration to 11-48% at 10 mg Cd/l). On the other hand, with a low Cd concentration (1 mg Cd/l), the percentage of Cd biosorbed by the bacterium ZAN-044 was maximum (69%) at pH 7, while this bacterium did not grow at 10 mg Cd/l and it did not accumulate Cd. For the three micro-organisms tested, relatively low specific biosorptions of Cd were observed, when the microorganisms were cultivated with a soil extract medium ('poor' medium), comparatively to those with a 'rich' medium. Finally, the choice of microorganism for the inoculation of contaminated soils depends on the cadmium level in the medium and on the distribution of the metal between the biomass and the medium.

Actinomycetales↗
PubMed2002

Temporal evolution of copper distribution in soil fractions, influence of soil pH and organic carbon level on copper distribution.

The present paper deals with the temporal evolution, over 6 years, of copper distribution in soil fractions using a sequential extraction procedure isolating five soil fractions which are operationally defined but commonly identified as : F1 = exchangeable metals, F2 = metals bound to organic matter, F3 = metals bound to manganese oxides, = metals bound to iron oxides and F5 = the residual fraction. The soil studied was a silty agricultural soil whose four plots were deliberately enriched with copper sulphate in October 1992 and one of them was also enriched with organic matter, another one with lime and the last one with both organic matter and lime. The great advantage of such an experimental procedure was that the five plots represent the same soil and thus had the same soil texture. It was then possible to fully describe anthropogenic copper behaviour, and to describe clearly the influence of pH and organic carbon level on copper distribution. Furthermore, the plots were subjected to natural climatic conditions allowing a temporal study of copper distribution under natural conditions. The total Cu level as well as Cu-F3 and Cu-F4 were clearly decreasing with time. Copper concentration in artificially defined soil fractions were described with multiple regression equations with the variable total copper content (TCu) and with the variables soil pH and soil organic carbon level when required. Cu-F1 and Cu-F2 depended on soil pH and soil organic carbon level, while Cu-F3 depended only on TCu. Copper level bound to iron oxides depended on soil pH.

Agriculture↗
PubMed2002

[Acute generalized exanthematous pustulosis due to fluconazole].

INTRODUCTION: Fluconazole (Triflucan(R)), a systemic triazole antifungal agent is largely prescribed and some cutaneous side effects have already been described. We report the first case of acute generalized exanthematous pustulosis due to this molecule in a patient with cutaneous candidosis. CASE REPORT: A 65 year-old-woman was treated with fluconazole (200 mg/day) for a persistent cutaneous candidosis infection on the buttocks. After the third dose, the patient presented with a pustular eruption with erythema located on her trunk and in her large skin folds. The eruption was associated with fever at 39 degrees C, asthenia and neutrophilia (9,000/mm(3)). The histologic examination and the negativity of microbiological cultures were consistent with the diagnosis of acute generalized exanthematous pustulosis. The eruption cleared with local steroids in about ten days. Nineteen days later, the same pustular eruption occurred but without fever nor neutrophilia. DISCUSSION: Clinical, biological and histological manifestations were consistent with the diagnosis of acute generalized exanthematous pustulosis due to fluconazole. According to the imputability criteria of Begaud et al., intrinsic imputability of fluconazole was possible (I2). According to the classification of the EuroSCAR study, it was certain. No similar case of recurrence had already been described after the withdrawal of the molecule. We believe this is the first case of acute generalized exanthematous pustulosis due to fluconazole (extrinsic imputability: B0).

Acute Disease↗
PubMed1999

Optimisation of plant sterols incorporation in human keratinocyte plasma membrane and modulation of membrane fluidity.

The in vitro effects of plant sterols were investigated with regard to their uptake and membrane lipid fluidity in human keratinocytes. Among the different media tested to transport sterols (liposomes, micelles and organic solvents), the best results in terms of incorporation and viability were obtained by the use of the organic solvents dimethylsulfoxide and ethanol. After 48 h incubation exogenous sterol can account for about 30% of the total cell sterol content. The total sterol amount in plasma membranes increased 2-fold after incubation with cholesterol, whereas it was not altered when phytosterols were incorporated. The incorporation of cholesterol, sitosterol and stigmasterol led to an increase in the percent of unsaturated fatty acid C18:1 in the plasma membrane. The effect of this uptake on membrane fluidity was studied by means of fluorescence polarisation using DPH and TMA-DPH as fluorescent probes. Whereas cholesterol and sitosterol had no significant effect on the DPH fluorescence anisotropy (rs), the presence of stigmasterol induced a 12% decrease of rs reflecting an increase in membrane fluidity. We can conclude from this study that in the presence of sitosterol, the mean fluidity of the membrane is regulated whereas stigmasterol triggers a looseness of molecular packing of phospholipids acyl chains, in accordance with previous results obtained on purely lipid model membranes.

Cell Line↗
PubMed1997

Compensatory renal growth post fetal nephrectomy in the rabbit.

Compensatory renal growth post-nephrectomy is well documented both clinically and experimentally. However, little is known about the capacity for compensatory growth in utero. We performed unilateral nephrectomy in fetal rabbits and studied the growth of the contralateral kidney. Thirty fetal rabbits underwent in utero uninephrectomies at day 25 of gestation. On gestational day 28, all the fetuses were delivered by cesarean section and the ratios kidney weight/body weight of the operated fetuses were compared to those of control littermates. The kidneys were then analysed by histology. A significant increase in renal weight was observed. The histological study of the remaining kidneys indicated a statistically significant increase of the glomerular area which confirmed the renal hypertrophy. This experiment demonstrates the capacity for the rabbit to develop in utero compensatory renal growth.

Animals↗
PubMed1993

CL307-24, a new antibiotic complex from Saccharopolyspora aurantiaca sp. nov. II. Physico-chemical and biological properties.

CL307-24I, the main component of the CL307-24 complex produced by Saccharopolyspora aurantiaca sp. nov., was found to be a potent inhibitor of yeast mitochondrial ATPase. CL307-24I displayed a high degree of activity towards some coryneform bacteria and also has been shown to possess an insecticidal activity. Its biological and physico-chemical properties clearly distinguish it from previously known ATPase inhibitors.

Adenosine Triphosphatases↗