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Biomedical subjects

V Bex

Publications and source records attributed to V Bex.

15 recordsLinked to original sources

[Kyphoplasty for the treatment of painful vertebral hemangioma].

Vertebral angiomas are frequent and often asymptomatic. Sometimes although they do not seem invasive radiologically, they are responsible for local pain. If there is concordance between pain and vertebral angioma localisation, surgery such as vertebroplasty or cyphoplasty can be proposed. These techniques lead to a quick and complete removal of symptoms.

Female↗

Detection of Mycobacterium tuberculosis complex by PCR in hospital air samples.

Tuberculosis remains a health problem in many developed countries. After the development of a sedimentation method, a semi-quantitative approach for bioaerosol monitoring of Mycobacterium tuberculosis based on polymerase chain reaction (PCR) was adapted for direct detection in air. Bovine serum albumin was added to override airborne environmental particle PCR inhibitors. The method gave positive results in hospital rooms where tubercular pneumonia patients were hospitalized during the first days after their diagnosis.

Adult↗

[Pollen content of the Paris air: comparison of the results obtained by two samplers for the year 2003].

During the 2003 season, a second pollen collector has been established in Paris city (Audubon site) to study the representativeness of the initial collector situated on the roof of the Pasteur Institute. The Hygiene Laboratory of Paris followed the pollen counts from the two collectors, during the period going from May to September. Both the samplers are Lanzoni model with a flow rate of 10 l x min(-1). The quantitative results show that no statistical difference exists between the pollen counts obtained from the 2 sites (Mann-Withney test, p > .05). The dominant species are Urticaceae, Poacae and Castenea species for the 2 collectors. Their counts are similar except for Poacae whose results are higher at the Audubon site. The collection period do not take into account the pollen production period of many trees species because of the late installation of the collector on the Audubon site. The results show that the two sites chosen for the study of pollen distribution are comparable. Nevertheless, the comparative study should be maintained on the next year to get more details about the observed differences and to collect the early trees pollen.

Air↗

[Environmental audits in Ile-de-France].

Mould exposure in indoor environments can cause various health effects: infections, allergies, toxic effects and irritations. We have lead environmental audits (n = 32), at physician's request, in suspected mould allergic patient homes. A deep home visit allows the detection of potential indoor fungal and humidity sources, afterwards, a sample strategy is determinate. Results show that indoor airborne spores concentrations vary from some units (CFU) to more than thousands per m3. In dust samples, the number of spores per gram ranges from hundred to millions. A statistical analysis shows that "mouldy dwellings" are more contaminated than "non mouldy" ones and than outdoor air. Mould species relative presence is specific in each contaminated home, depending on various factors (mouldy support nature, competition between species...).

Air↗

A novel mutation in DAX1 causes delayed-onset adrenal insufficiency and incomplete hypogonadotropic hypogonadism.

Mutations in the DAX1 gene cause X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HHG). In affected boys, primary adrenal insufficiency occurs soon after birth or during early childhood; HHG is recognized at the expected time of puberty. In this report, we describe the novel phenotype of a man who presented with apparently isolated adrenal insufficiency at 28 years of age. Examination revealed partial pubertal development and undiagnosed incomplete HHG. Gonadotropin therapy did not improve his marked oligospermia, suggesting a concomitant primary testicular abnormality. Genomic analysis revealed a novel missense mutation, I439S, in DAX1. The mutant DAX-1 protein was studied for its ability to function as a transcriptional repressor of target genes. Consistent with the patient's mild clinical phenotype, the I439S mutation conferred intermediate levels of repressor activity of DAX-1 when compared with mutations associated with classic AHC. This unique case extends the clinical spectrum of AHC to include delayed-onset primary adrenal insufficiency in adulthood and milder forms of HHG. Furthermore, in accordance with findings in Ahch (Dax1) knockout mice, the clinical features in this patient suggest that DAX-1 function is required for spermatogenesis in humans, independent of its known effects on gonadotropin production.

Adrenal Glands↗

The polarized hepatic human/rat hybrid WIF 12-1 and WIF-B cells communicate efficiently in vitro via connexin 32-constituted gap junctions.

Gap junction intercellular communication (GJIC) plays an essential role in the control of growth, differentiation, and functions of different tissues. The expression of connexins (Cxs), the structural proteins of gap junctions, is developmentally regulated and tissue-specific. In vivo hepatocytes express Cx32 and Cx26. Most currently available in vitro hepatic cell systems express Cx43 instead of the expected Cxs. This work analyzes the GJIC competence and Cx expression of the highly differentiated and polarized hepatoma-derived hybrid cell lines, WIF 12-1 and WIF-B. It shows (using two dye transfer assays) that both lines communicate efficiently and that the acquisition of GJIC competence precedes the formation of bile canaliculi. Interestingly, these cells communicate via Cx32 expression, whereas Cx26 and Cx43 are not expressed, as demonstrated by Western and Northern blotting, immunocytochemistry, and confocal microscopy. The human fibroblast W138 parent communicates via Cx43, whereas the rat hepatoma parent Fao and the subclone WIF 12-1 TGdelta, that has lost the human X chromosome, do not communicate, the expression of Cx32 being restricted to the mRNA in these two lines. The GJIC competence of WIF cells could thus result from the activation of the human X chromosome-linked Cx32 gene.

Animals↗

Flavonoids (apigenin, tangeretin) counteract tumor promoter-induced inhibition of intercellular communication of rat liver epithelial cells.

We have shown previously that two flavonoids, apigenin and tangeretin, enhance gap junctional intercellular communication (GJIC) in rat liver epithelial cells, named REL cells. Here, we show that these two flavones also antagonize the inhibition of GJIC induced by tumor promoters like 12-O-tetradecanoyl-phorbol-acetate (TPA) and 3,5,di-tertio-butyl-4-hydroxytoluene (BHT). Their preventive effect is rapid. It does not seem to involve any change of the amount of the connexin expressed in REL cells, connexin 43 (Cx 43), and in its phosphorylation state. Other flavonoids tested including naringenin, myricetin, catechin and chrysin did not enhance GJIC nor counteract TPA-induced inhibition of GJIC.

Animals↗

Retinoic acid enhances connexin43 expression at the post-transcriptional level in rat liver epithelial cells.

The mechanism by which all-trans retinoic acid (RA) stimulates gap junctional intercellular communication (GJIC) in the rat liver epithelial cell line. IAR203, was investigated. When RA, at 0.1 microM for 24-48 h, enhanced the dye transfer in IAR203 cells (x 1.4), it increased the amount of connexin43 (Cx43) in the cell-cell contact regions of the plasma membrane, as evidenced by analysis by Western blot and by immunofluorescence. It had no effect on the level of Cx43 mRNA. Freeze-fracture analysis of the size of gap junctions revealed an increase of the proportion of small gap junctions in RA-treated cells. We conclude that, in IAR203 cells, RA stimulates GJIC by acting at the post-transcriptional level of Cx43 regulation. The possibility that RA acts indirectly on the regulation of Cx43 expression, and increases the half-life of Cx43 by inducing adhesion molecules is discussed.

Animals↗

Apigenin and tangeretin enhance gap junctional intercellular communication in rat liver epithelial cells.

Two flavones, apigenin and tangeretin, were studied for their ability to modulate gap junctional intercellular communication (GJIC) in the rat liver epithelial cell line REL. Their cytotoxicity was first determined by cell density and neutral red uptake assays: neither apigenin nor tangeretin are cytotoxic at 10 and 25 microM, the concentrations used in our experiments. We then studied GJIC using the dye transfer assay and we observed that both apigenin and tangeretin enhance it, the maximum stimulation (x 1.7-1.8) being achieved at 25 microM for 24 h. When the dye transfer was enhanced, the amount of connexin 43 increased, which was demonstrated by Western blot and immunofluorescence analysis. For apigenin only, Northern blot analysis showed an accumulation of connexin 43 mRNA. In addition, the incubation of REL cells with the two compounds, for 1 or 24 h, prevented the inhibition of dye transfer by 12-O-tetradecanoylphorbol-13-acetate (1 or 10 ng/ml). The enhancement of GJIC by apigenin could be one of the major mechanisms responsible for apigenin's anti-tumour promoting action in vivo. As for tangeretin, its capacity to enhance GJIC completes its potential protective properties towards the post-initiation process.

Animals↗

[Multifocal germ cell tumors].

A 16-year old male presented with a mediastinal germ cell tumor (seminoma) treated by combined surgery, radiotherapy and chemotherapy. Nine years later, he presented with an intracerebral germ cell tumor affecting both the suprasellar ventricles and the pineal area. After partial removal of the intraventricular tumor, the patient received radiotherapy and chemotherapy. No metastases could be found. He died 8 months later, probably from secondary cardiovascular disturbances. This case seems to be the first one to illustrate the possibility of multifocal extragonadal seminoma.

Adolescent↗

Neoplastic progression of human and rat intestinal cell lines after transfer of the ras and polyoma middle T oncogenes.

BACKGROUND: Activation of the p21ras and pp60c-src oncoproteins occurred at high incidence in the early stage of human colorectal carcinogenesis. Our study aimed to investigate the role of these signal-transduction pathways in the process of initiation and promotion of the malignant phenotype in intestinal cells. METHODS: The human Ha-ras and the polyoma middle T (Py-MT) viral oncogenes were transferred into large T oncogene of simian virus 40 immortalized rat intestinal epithelial SLC-44 cells and human colonic adenocarcinoma Caco-2 cells. RESULTS: These transfers conferred the tumorigenic and invasive phenotypes on immortalized SLC-44 cells and potentiated the tumorigenicity of Caco-2 cells and markedly repressed the terminal differentiation of this cell line. In SLC-44T cells, induction of the invasive phenotype by the activated Ha-ras oncogene correlated with weak expression of E-cadherin and reduced accumulation of the transcripts encoding the basement membrane components alpha 1 (IV) collagen, nidogen, and BM40, which might result partly from the inactivation of the transforming growth factor beta signaling pathway. The down-regulation of the alpha 1 (IV) collagen messenger RNA in SLC-44T cells was not due to the protein kinase C-dependent pathways or the secretion of autocrine factor(s). CONCLUSIONS: These results suggest that the activation of the p21ras and Py-MT/pp60c-src oncogenic pathways are critical effectors at different stages of colorectal carcinogenesis and in Caco-2 cells interferes with the program of enterocyte differentiation.

Animals↗

Focal brain invasion as the first manifestation of Langerhans cell histiocytosis in an adult. Case report.

A 31-year-old overweight man, suffering from high-blood pressure, was hospitalized for transient fits and hemiparesis. MRI disclosed a large irregular mass affecting the vault, meninges and invading the parietal lobe. At neurosurgery, the lesion was necrotic, hemorrhagic and poorly demarcated from the surrounding brain. Histopathology revealed a benign Langerhans cell histiocytosis. No other systemic nor organic lesions could be discovered. After additional local radiotherapy, the patient recovered completely and regained normal activities 6 months later.

Adult↗