References of "Houssa, P"
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See detailA novel messenger ribonucleic acid homologous to human MAGE-D is strongly expressed in rat Sertoli cells and weakly in Leydig cells and is regulated by follitropin, lutropin, and prolactin.
Hennuy, Benoît ULg; Reiter, E.; Cornet, Anne ULg et al

in Endocrinology (2000), 141(10), 3821-31

We have cloned a novel complementary DNA whose expression was decreased in rat Sertoli cell cultures after treatment with FSH. This complementary DNA encodes a protein of 570 amino acids and shares 92 ... [more ▼]

We have cloned a novel complementary DNA whose expression was decreased in rat Sertoli cell cultures after treatment with FSH. This complementary DNA encodes a protein of 570 amino acids and shares 92% homology with the human MAGE-D protein. In contrast to other MAGE genes (A, B, or C), we have shown that MAGE-D expression was ubiquitous in healthy rat tissues. In the seminiferous tubules, the MAGE-D was expressed in Sertoli cells but not in germ cells as demonstrated by RT-PCR and in situ hybridization, whereas for the other MAGE genes, expression has been shown to be restricted to germ cells. Interestingly, MAGE-D was also detected for the first time in the female gonad by Northern blotting. In MLTC-1 cells (mouse Leydig tumor cell line-1), LH and PRL stimulated MAGE-D expression. Using hypophysectomized rats, it was confirmed that FSH decreased MAGE-D expression, whereas LH and PRL increased MAGE-D messenger RNA level in the whole testis most probably through a direct action on Leydig cells. As MAGE-D is present in both the seminiferous compartment and interstitium and hormonally regulated in each, it is possible that it has specific functions in each compartment during the development and the maintenance of the testis. [less ▲]

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See detailA novel gene overexpressed in the prostate of castrated rats: hormonal regulation, relationship to apoptosis and to acquired prostatic cell androgen independence.
Bruyninx, M.; Hennuy, Benoît ULg; Cornet, Anne ULg et al

in Endocrinology (1999), 140(10), 4789-99

We have identified a novel complementary DNA (cDNA) corresponding to a gene overexpressed in the rat ventral prostate after castration. This cDNA displays 89.4% identity with 453 bp of a mouse EST and 81 ... [more ▼]

We have identified a novel complementary DNA (cDNA) corresponding to a gene overexpressed in the rat ventral prostate after castration. This cDNA displays 89.4% identity with 453 bp of a mouse EST and 81.5% identity with 157 bp of a human EST and was named PARM-1 for prostatic androgen-repressed message-1. The complete cDNA is 1187 bp long and codes for a protein of 298 amino acids that contains four potential glycosylation sites and three half cystinyl residues. The PARM-1 gene was found to be expressed at quite low levels in most rat tissues including those of the urogenital tract. The kinetic of induction of PARM-1 gene in the prostate was highly correlated to the development of apoptosis in the whole organ. Supplementation of castrated animals with androgens reversed both the process of apoptosis and the overexpression of PARM-1 gene. Supplementation with estrogens did not result in an increase in the PARM-1 messenger RNA levels when compared with the castration alone. However, the treatment resulted in a more rapid return to intact levels in the castrated plus estrogen group. When apoptosis of testis and prostate was induced in vivo by hypophysectomy, it was found that PARM-1 was only overexpressed in the prostate. Therefore, PARM-1 seems to be regulated by androgens only in the prostate. Using in situ hybridization and immunohistological techniques, we have shown that PARM-1 gene product is found exclusively in the epithelial cells of involuting prostate. Analysis by flow cytometry of MAT LyLu epithelial cells transiently expressing PARM-1 protein did not allow us to demonstrate a direct effect of PARM-1 gene overexpression on the programmed death of the transfected cells. Treatment of MAT LyLu cells by transforming growth factor-beta induced apoptosis but had no effect on PARM-1 production. However PARM-1 protein has been detected by Western blotting in various cell lines such as MAT LyLu, MAT Lu, and PIF, which are androgen independent. This would suggest that PARM-1 gene product would be a marker for acquired androgen-independence of these tumor cells. [less ▲]

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See detailHighly Specific Radioimmunoassay for Human Insulin Based on Immune Exclusion of All Insulin Precursors
Deberg, Michelle ULg; Houssa, P.; Frank, B. H. et al

in Clinical Chemistry (1998), 44(7), 1504-13

We describe a rapid and simple insulin RIA in which proinsulin and conversion intermediates do not interfere. Three monoclonal antibodies (S1, S2, and S53) were selected for their specificity (directed ... [more ▼]

We describe a rapid and simple insulin RIA in which proinsulin and conversion intermediates do not interfere. Three monoclonal antibodies (S1, S2, and S53) were selected for their specificity (directed, respectively, against the B10 region, the junction between A chain and C-peptide, and the junction between B chain and C-peptide), their affinity constant (approximately 10(10) L/mol), and their interactive properties in mixture. S2 and S53 were able to bind simultaneously to the same proinsulin molecule, whereas neither could bind simultaneously with S1. Preincubation of serum samples with an excess of S2 resulted in capture of proinsulin and conversion intermediates modified at the junction between B chain and C-peptide into immune complexes that no longer reacted with S1. Similarly, preincubation with S53 prevented proinsulin and conversion intermediates modified at the junction between A chain and C-peptide from reacting with S1. Preincubation with an excess of both S2 and S53 left insulin as the sole reactant with S1. Thus, separation of insulin precursors from insulin by mutually exclusive antibodies is feasible, and on the basis of this new principle, a highly specific RIA for insulin was designed. The detection limit was 11 pmol/L, and the inter- and intraassay coefficients of variation were 11% and 5%, respectively. The potential of the assay for use in clinical studies was verified by application to serum samples from control subjects and patients with diabetes or insulinoma. [less ▲]

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See detailFirst Direct Assay for Intact Human Proinsulin
Houssa, P.; Dinesen, B.; Deberg, Michelle ULg et al

in Clinical Chemistry (1998), 44(7), 1514-9

We describe a sensitive two-site sandwich enzyme-linked immunosorbent assay for the measurement of intact human proinsulin in 100 microL of serum or plasma. The assay is based on the use of two monoclonal ... [more ▼]

We describe a sensitive two-site sandwich enzyme-linked immunosorbent assay for the measurement of intact human proinsulin in 100 microL of serum or plasma. The assay is based on the use of two monoclonal antibodies specific for epitopes at the C-peptide/insulin A chain junction and at the insulin B chain/C-peptide junction, respectively. Cross-reactivities with insulin, C-peptide, and the four proinsulin conversion intermediates were negligible. The detection limit in buffer was 0.2 pmol/L (3 standard deviations from zero). The working range was 0.2-100 pmol/L. The mean intra- and interassay coefficients of variation were 2.4% and 8.9%, respectively. The mean recovery of added proinsulin was 103%. Dilution curves of 40 serum samples are parallel to the proinsulin calibration curve. Proinsulin concentrations in 20 fasting healthy subjects were all above the limit of detection: median (range), 2.7 pmol/L (1.1-6.9 pmol/L). Six fasting non-insulin-dependent diabetes mellitus and five insulinoma patients had proinsulin concentrations significantly higher than healthy subjects: median (range), 7.7 pmol/L (3.2-18 pmol/L) and 153 pmol/L (98-320 pmol/L), respectively. [less ▲]

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