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Biomedical subjects

G Benoit

Publications and source records attributed to G Benoit.

At least 91 records · Page 5Linked to original sources
PubMed1995

Analysis of cadaver donor criteria on the kidney transplant survival rate in 5,129 transplantations.

PURPOSE: To clarify the role of donor criteria we retrospectively analyzed a series of 5,129 cadaver kidney grafts harvested from January 1, 1989 to December 31, 1991. MATERIALS AND METHODS: Graft survival was calculated and analyzed using a multifactorial approach. RESULTS: Better graft survival was obtained with donors between 6 and 50 years old (80% versus 64% at 3 years), grafts performed from male donors (74% versus 69% at 3 years), donor deaths caused by cranial injury as opposed to cerebral hemorrhage (74% versus 70% at 3 years) and negative cytomegalovirus antibodies (75% versus 71% at 3 years). CONCLUSIONS: These factors may be used for kidney allocation.

Adolescent↗
PubMed1995

Neural control of penile erection.

Filling of the sinusoidal spaces with blood due to smooth muscle relaxation results from parasympathetic neural pathway activation and probably simultaneous inhibition of sympathetic outflow. The final common pathway for proerectile fibers is represented by the cavernous nerves and fibers controlling detumescence and flaccidity originating in the sympathetic chain. The hypogastric nerve could represent an accessory proerectile pathway unmasked by a sacral spinal cord lesion. Nitric oxide, which can be colocalized with VIP and acetylcholine, is the main proerectile neurotransmitter and noradrenaline is considered to be the major antierectile agent. Reflexive erection elicited by recruitment of penile afferents involves both autonomic and somatic efferents. This reflex is mediated at the spinal cord level and modulated by supraspinal influences. Serotonergic pathways originating in the raphe nuclei may mediate inhibitory control on reflexive erections. The hypothalamic medial preoptic area is an important integrating center and dopamine may regulate penile erection at this level. Neuroendocrine regulation may vary depending on the context in which erection occurs, for example, coitus, in response to extrinsic or psychogenic stimuli, and rapid eye movement sleep.

Animals↗
PubMed1995

Enhanced detection of hematogenous circulating prostatic cells in patients with prostate adenocarcinoma by using nested reverse transcription polymerase chain reaction assay based on prostate-specific membrane antigen.

We report the development of a new sensitive nested reverse transcription-polymerase chain reaction (RT-PCR) assay, using primers derived from the prostate-specific membrane antigen (PSM) cDNA sequence, to detect an hematogenous spread of prostate adenocarcinoma cells. In 60 patients with a biopsy-proven prostate cancer, PSM and PSA RT-PCR detected circulating prostate cells in 40 and 20 patients, respectively. In pT4 M+ and pT3 M+ disease patients, nested PSM primers detected cells in 28 of 33 patients (85%), whereas nested PSA primers detected cells in 17 of 33 (51%). In patients with organ-confined cancer spread (pT2a and pT2b patients) before radical prostatectomy, nested PSM RT-PCR detected circulating prostatic epithelial cells in 6 of 17 patients (35%), which suggests that an hematogenous spread of prostate cells may occur early in prostate cancer history. Altogether, these results suggest that the detection of PSM-expressing cells in blood may predict the development of cancer in patients without clinically apparent prostate cancer. Nevertheless, the potential application and the clinical significance of detection of hematogenous prostate cells through the use of nested PSM primers need an extensive longitudinal study.

Adenocarcinoma↗
PubMed1995

[Treatment using concomitant radiochemotherapy of N+ M0 stage urothelial tumors of the bladder].

Seventeen patients with N+ urothelial bladder tumours were treated by a combination of deep endoscopic resection and concomitant radiochemotherapy (5FU cisplatin). 15 patients completed their course of treatment. 52.9% of these 17 patients are in complete remission at 6 months, 35.2% are in complete remission at 1 year, 30% of patients in complete remission developed distant metastases, 52.9% developed local progression and 40% developed distant metastases. This protocol of deep resection combined with radiochemotherapy can therefore be effective in the local control of the tumour and can allow preservation of the bladder in the case of complete remission. However, it is insufficient to prevent the development of distant metastases. It is therefore preferable to intensify this treatment by performing complete endoscopic resection, by increasing the radiotherapy dose rate and by intensifying the chemotherapy protocol.

Adult↗
PubMed1995

Distinct apoptotic responses in maturation sensitive and resistant t(15;17) acute promyelocytic leukemia NB4 cells. 9-cis retinoic acid induces apoptosis independent of maturation and Bcl-2 expression.

Apoptosis has been investigated in NB4, a t(15;17) human promyelocytic leukemia cell line susceptible to maturation by all-trans or 9-cis retinoic acid, and in NB4-R1, a subclone resistant to differentiation. Maturation resistant NB4-R1 cells exhibited an onset of cell death after RA-treatment (72 h), whereas maturation responsive NB4 cells showed no such apoptosis, cell death being considerably delayed after cell maturation. Only a few NB4-R1 cells underwent apoptosis in response to low doses of RA (below 0.1 microM), the surviving cells became refractory to higher doses of RA. While these cells became 'resistant' to apoptosis they became competent for maturation. Typically, these RA-'primed' cells responded to cAMP by maturation, then apoptosis followed rapidly. This model furnishes situations where cells are either resistant or susceptible to apoptosis, depending on whether they can or cannot undergo maturation. The potential role of the Bcl-2 protein in the regulation of apoptosis was analyzed. In NB4 and NB4-R1 cell lines, a high expression of the Bcl-2 protein was detected by immunocytology and Western blotting. NB4 cells treated with either all-trans or 9-cis retinoic acid (1 microM) were induced to differentiate and the level of Bcl-2 protein decreased to undetectable levels during terminal maturation when only a few apoptotic cells were detected. In NB4-R1 cells, while treatment with retinoids does not induce maturation, as much as 64% of cells became apoptotic, and immunocytological labelling of NB4-R1 showed a strong cytoplasmic labelling of Bcl-2. Although the expression of Bcl-2 remained high, cells were not protected from apoptosis. To assess whether Bcl-2 expression could be modulated as a consequence of differentiation, NB4-R1 cells previously 'primed' for maturation were triggered with cAMP. Downregulation of Bcl-2 protein occurred concomitant with maturation, followed by apoptosis. Clearly, NB4 and NB4-R1 cells show reciprocal behavior with regards to proliferation, maturation, Bcl-2 regulation and apoptosis in response to RA. Our results suggest, first, that the Bcl-2 downregulation in NB4 cells belongs to the maturation program rather than to apoptosis, and second, that neither a high Bcl-2 expression in NB4 cells is sufficient to protect cells from 9-cis RA induced apoptosis, nor is its full downregulation sufficient to produce apoptosis. Finally, this work suggests that apoptosis and maturation programs include events which cannot occur simultaneously.

Apoptosis↗
PubMed1994

Structural organization, sequence, and expression of the mouse HEXA gene encoding the alpha subunit of hexosaminidase A.

Genomic clones of the mouse HEXA gene encoding the alpha subunit of lysosomal beta-hexosaminidase A have been isolated, analyzed, and sequenced. The HEXA gene spans approximately 26 kb and consists of 14 exons and 13 introns. The 5' flanking region of the gene has three candidate GC boxes and a number of potential promoter and regulatory elements. Promoter analysis using deletion constructs of 5' flanking sequence fused to the bacterial chloramphenicol acetyltransferase (CAT) gene showed that 150 bp of 5' sequence was sufficient for expression in transfected monkey kidney COS cells. Determination of the sequence of the 5' end of the Hex alpha mRNA by an "anchor-ligation PCR" procedure showed that transcription is initiated from a cluster of sites centered -42, -32, and -21 bp from the first in-frame ATG. Northern blot analysis from 11 different tissues showed over five times the steady-state level of Hex alpha mRNA in testis as compared to that found in three different brain regions; the lowest level (about 1/3 of brain) was found in liver. Comparison of the 5' flanking sequence with that of the human HEXA gene revealed 78% identity within the first 100 bp. These data suggest that the mouse HEXA gene is controlled mainly by sequences located within 150 bp of the 5' flanking region, and we speculate that it may have a role, not only in brain and other tissues, but also in reproductive function in the adult male mouse.

Amino Acid Sequence↗
PubMed1994

Characterization of the murine beta-hexosaminidase (HEXB) gene.

The murine HEXB gene, encoding the beta-subunit of the lysosomal hydrolase, beta-hexosaminidase, was isolated from a mouse cosmid library as a single cosmid clone. The entire gene spans 22 kb, considerably less than the 40 kb spanned by its human counterpart. It is highly homologous to the human gene. The 14 intron-exon junctions are entirely conserved, although the intron sequences diverge rapidly. Upstream of the coding region, a 1.3 kb segment was sequenced and shown to function as a promoter when fused with a reporter gene and expressed in monkey COS-7 cells. A short sequence (100 bp), near the start of the coding region, exhibits strong homology to the human HEXB promoter. Analysis of the tissue distribution of the HEXB mRNA in 129/Sv male mice revealed up to 28-fold tissue-specific variations in transcript levels. The kidney and the epididymis had the highest mRNA levels consistent with past surveys of enzyme activity.

Amino Acid Sequence↗
PubMed1994

Anatomy of the prostatic nerves.

The entire prostate of a 10 year old boy was cut with a microtome in to 4300 serial slices. The nerves were stained using a monoclonal antibody called anti PS 100. All information was recorded using a computer reconstruction programme. The prostatic nerve supply is very abundant. The nerve fibers of the cranial prostate (central zone) follow a pathway parallel to the anterior surface of the seminal vesicles going towards the caudal prostate. The periurethral zone is widely innervated by nerves arising from the periphery. The caudal prostate also contains many nerve fibers of variable size. We identified many nerve fibers along the anterior surface of the seminal vesicles and surrounding the lateral aspect of the prostatic capsule. They penetrate the capsule and the whole circumference of the caudal prostate. The prostatic capsule is covered by numerous nerve fibers and ganglia, which form a true periprostatic nerve network. The urethra is supplied by numerous thick fibers of more than 30 microns in diameter.

Child↗