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Biomedical subjects

P Bourgeois

Publications and source records attributed to P Bourgeois.

At least 73 records · Page 4Linked to original sources
PubMed1997

Regulation of argininosuccinate synthetase mRNA level in rat foetal hepatocytes.

Expression of the hepatic gene for argininosuccinate synthase (ASS), one of the key enzymes of the urea cycle, was analysed during the perinatal period in the rat. To this end, the amount of specific mRNA was measured in the liver at various stages of development and in cultured foetal hepatocytes maintained in different hormonal conditions. The ASS mRNA was first detected in 15.5-day foetuses and its level increased concomitantly with a rise in the enzyme activity, suggesting that the appearance of the ASS activity reflects the turning on of specific gene transcription. This was demonstrated by run-on assay which showed an enhanced rate of transcription of the ASS gene during the perinatal period. When foetal hepatocytes were cultured with dexamethasone, a dose-dependent increase in ASS mRNA was measured, which was completely abolished by actinomycin D addition. The transcription rate of the gene was increased about twofold in the presence of the steroid, as measured by nuclear run-on assay. This transcriptional action could additionally require a protein factor since it could be inhibited by the simultaneous addition of puromycin. Insulin or glucagon respectively repressed or enhanced the dexamethasone-induced accumulation of ASS mRNA when added simultaneously with the steroid for 24 h. This developmental regulation of the ASS mRNA by glucocorticoids, insulin and glucagon could account for the modulation of the enzyme activity previously observed in vivo and in vitro in the foetal liver.

Animals↗
PubMed1997

Mutations of the TWIST gene in the Saethre-Chotzen syndrome.

Saethre-Chotzen syndrome (acrocephalo-syndactyly type III, ACS III) is an autosomal dominant craniosynostosis with brachydactyly, soft tissue syndactyly and facial dysmorphism including ptosis, facial asymmetry and prominent ear crura. ACS III has been mapped to chromosome 7p21-22. Of interest, TWIST, the human counterpart of the murine Twist gene, has been localized on chromosome 7p21 as well. The Twist gene product is a transcription factor containing a basic helix-loop-helix (b-HLH) domain, required in head mesenchyme for cranial neural tube morphogenesis in mice. The co-localisation of ACS III and TWIST prompted us to screen ACS III patients for TWIST gene mutations especially as mice heterozygous for Twist null mutations displayed skull defects and duplication of hind leg digits. Here, we report 21-bp insertions and nonsense mutations of the TWIST gene (S127X, E130X) in seven ACS III probands and describe impairment of head mesenchyme induction by TWIST as a novel pathophysiological mechanism in human craniosynostoses.

Acrocephalosyndactylia↗
PubMed1997

Visuvalve software: an aid to the diagnosis of shunt failure.

Software designed to help the neurosurgeon in the diagnosis of shunt malfunction is presented. This software allows the possibility to record on a 3.5 diskette a patient's clinical information and four views of a CT scan performed when the patient was doing perfectly well with his shunt. This diskette, operated by MS-DOS on any IBM-compatible personal computer, can be read at any time, anywhere. The evaluation of the system demonstrated it was safe, with an excellent adhesion of the patients and of their families.

Cerebral Ventriculography↗
PubMed1997

An epidemiological study of diagnostic and therapeutic strategies in office practice patients with subacute or chronic pain in the thoracic or low back. Comparison of practices in primary care and rheumatology settings.

UNLABELLED: There is a paucity of epidemiological data on diagnostic and therapeutic practices in office practice patients with subacute or chronic pain in the thoracic or low back. STUDY OBJECTIVE: to describe diagnostic and therapeutic strategies used in such patients. PATIENTS AND METHODS: descriptive, prospective, two-month epidemiological study in 50 general practitioners and 50 rheumatologists. Each physician was asked to provide data on the demographics, clinical features, history of spinal disease, investigations, prior treatments and treatments prescribed on D0 and D30 in two patients with low back pain and two with thoracic back pain, of one to 12 months' duration. RESULTS: A total of 352 patients were included. In the 217 patients with low back pain, including 107 women and 110 men, duration of the pain was 4.3 +/- 0.2 months and mean age was 49.6 +/- 1 years; 67% of these patients were economically active and 22% were retired; 59% were recruited by rheumatologists. In the thoracic back pain group, there were 135 patients, including 82 women (61%) and 53 men, with a mean duration of pain of 3.8 +/- 0.3 months and a mean age of 47.7 +/- 1.4 years; 60% were economically active and 22% were retired; 49% were recruited by rheumatologists. A history of conservatively-treated low or thoracic back pain was reported for 95.4% of patients in the low back pain group and 94% in the thoracic back pain group. Of the patients with low back pain, 6.3% had had spinal surgery. Investigations were as follows: roentgenograms in 85% of low back pain and 75% of thoracic back pain patients, computed tomography in 11% and 5.8%, magnetic resonance imaging in 2% and 1% and laboratory tests in 14% and 20%. Ninety-one per cent of low back pain and 84% of thoracic back pain patients were already under therapy on D0. Ninety-six per cent of patients overall were given a prescription at the end of the D0 visit, for a nonsteroidal antiinflammatory drug or an analgesic in 80% of low back pain and 63% of thoracic back pain patients, for muscle relaxants in 62% and 69%, for drugs aimed at preventing gastric side effects in 19% and 9.5%, for myotonic agents in 10% and 8% and for sedatives in 5% and 11%. A local steroid injection was given to 20% of low back pain patients. Twenty-four per cent of low back pain and 14% of thoracic back pain patients missed days of work (mean, 11 +/- 1.7 days and 13 +/- 4.6 days, respectively). Physical therapy was prescribed to 36% of low back pain and 27% of thoracic back pain patients and a lumbar support belt to 17% of low back pain patients. On D30, the pain had abated in 86% of low back pain and 89% of thoracic back pain patients and complete freedom from pain was reported by 28% and 32% of patients in these two groups, respectively. Treatments prescribed on D30 were physical therapy (43% and 31%), analgesics (40% and 36%) muscle relaxants (25% and 30%), and nonsteroidal antiinflammatory drugs (23% and 12%). Conclusion. This preliminary study provides data on common practices in subacute and chronic low back and back pain and may prove useful for health care cost estimations.

Acute Disease↗
PubMed1997

[Sacral nerve root cysts. Discussion on the mechanism of nerve root suffering. Apropos of 4 cases].

Low back pain, sciatia or perineal chronic pain are sometimes related to perineural sacral cysts. Surgical treatment is difficult and may lead to pain or neurological worsening. We report four cases of symptomatic perineural cysts; three of them where operated on with two good results and one increasing perineal pain. Anatomical and radiological description are reviewed. From a therapeutical point of view, we can distinguish two clinical types of radicular suffering. Perineural cyst can cause a commun radicular extrinsic compression; in such a case surgical operation will improve radicular pain. The cystic nerve root can present an intrinsic suffering because of on intradural dilaceration. Then surgery must be avoided specially when many roots are involved because it may worsen the pluriradicular suffering.

Adult↗
PubMed1997

[Value of peroperative endoscopy in treating giant lumbosacral meningocele].

Lombosacral meningocele may be responsible for sciatica, low backache, cauda equina syndrome according to their localization and size. When they are symptomatic, the surgical purpose is to close the communication between the meningeal sac and the cyst. For giant meningocele, acute localization of the communication may be difficult. In such cases, peroperative endoscopy may be useful. We present a case of sciatica related to a giant meningocele extended from L2 to S2. MRI, CT scan and myelography were unable to localize the communication. We used peroperative endoscopy for direct visualization of the communication in order to minimize the surgical approach. An intrathecal nerve root was found strangulated in the communication suggesting an original kind of nerve root suffering. The communication was only closed. The patient made an uneventful recovery with complete relief of symptoms. Magnetic resonance imaging 3 months later showed a significant decrease of the meningocele without any further radicular compression.

Adult↗
PubMed1996

Donor vascular grafts for arterial reconstruction in pediatric liver transplantation.

The authors compared the results of 48 orthotopic liver transplantations (OLT) in which revascularization was achieved with a conduit interposed between the receptor aorta and the graft (vascular graft [VG] group) with those obtained for 56 OLT performed during the same period (1991 to 1994) in which end-to-end anastomosis (EEA) of the hepatic arteries or celiac trunk was used (EEA group). In the VG group, the interposed conduits were the cadaveric iliac artery (37) the living-donor saphenous vein (3), or nonthrombosed conduits from previous transplants (8) (7 iliac arteries, 1 saphenous vein). There were significant differences between the two groups with respect to recipient age, recipient weight, the retransplant:first transplant ratio, the number of emergency transplantations, the use of reduced-size grafts, and intraoperative transfusion requirements. Twenty-nine grafts in the VG group (60.4%) and 43 in the EEA group (76.7%) currently are functioning. The actuarial 3-year graft survival rates are 60% and 71.5% for the VG and EEA groups (P < .05), respectively. The rate of arterial thrombosis did not differ between the two groups. The authors conclude that, although EEA of the hepatic artery is still the preferred revascularization technique for OLT, revascularization of the liver graft by conduit interposition is safe when EEA is not possible. Reutilization of the interposed conduit during retransplantation proved to be safe in the absence of hepatic artery thrombosis.

Anastomosis, Surgical↗
PubMed1995

[Osteo-articular complications of heart transplantation].

Heart transplantation is an effective means of treating irreversible heart failure in selected patients. Preventing organ rejection requires immunosuppressor treatment with corticosteroids, azathioprine and/or cyclosporine. Bone and joint complications are frequent and increase overall morbidity directly related to anti-rejection therapy. Corticosteroids favour osteopenia which can be detected by measurement of bone density. The risks include spontaneous wedge fractures of the spine and aseptic necrosis. The frequency of complications has been reduced with the use of cyclosporine allowing a reduction in corticosteroids. Raised serum urate levels and increased risk of gout can be induced by cyclosporine. The gout in these patients has a particular course since it appears rapidly after only a few months of hyperuricaemia. Several joints may be involved with production of tophi. Treatment is particularly difficult. Its frequency increases after heart transplantation compared with other organs which can be explained by the more prevalent prescription of diuretics which further aggravate urate secretion. These complications cause further discomfort in transplant recipients.

Bone Diseases↗
PubMed1995

Dorso-ventral and rostro-caudal sequential expression of M-twist in the postimplantation murine embryo.

M-twist is the murine homolog of the Drosophila twist gene which is a zygotic target for maternal genes that establish embryonic dorso-ventral polarity and is necessary for mesoderm formation. We recently showed that before gastrulation, M-twist transcripts are detected in morulae and blastocysts, then in extra-embryonic tissues of early implanted mouse embryos before the onset of gastrulation, and we suggested that M-twist might be involved in embryonic polarity (Stoetzel et al., submitted). Here, using in situ hybridization on whole mount embryos, we present the expression pattern of M-twist from primitive streak stage up to 10.5 days p.c. In implanted embryos, M-twist is first expressed in extra-embryonic tissues, then in embryo proper around egg cylinder stage within some embryonic ectodermal cells of the primitive streak. Slightly later, scattered cells within the amniotic cavity apparently detached from the primitive streak also express the gene. Then, M-twist transcripts accumulate in head mesenchyme, the first aortic arches, somites and lateral mesoderm and, as development proceeds, successively the second, third and fourth branchial arches, the anterior limb buds and, finally, the posterior limb buds. Thus M-twist expression in implanted embryos occurs first along a dorso-ventral gradient pattern until the headfold stage, then it is gradually observed along the rostro-caudal axis of the embryos as development procedes in the mesodermal cell layer and in neural crest cell derivatives. In addition, we show the existence of some previously undescribed subsets of scattered cells that express M-twist and thus might participate in murine embryo development.

Animals↗
PubMed1995

Biodistribution of liposomes after extradural administration in rodents.

We have mapped over 24 h the biodistribution of 99mTc-labelled multilamellar and small unilamellar liposomes in rabbits and rats by scintigraphic imaging after extradural injection. Multilamellar vesicles formed a depot at the site of injection; small unilamellar vesicles spread immediately along the extradural space and entered the systemic compartment 30 min after injection. Well-delineated liver and kidney labellings were seen after 24 h. The use of 3H-cholesterol-labelled small unilamellar vesicles suggested hepatic capture of intact liposomes with sizes averaging 0.05 microns drained unmodified into the systemic circulation through the extradural lymphatics. These results have led to the selection of multilamellar vesicles (0.1-15 microns size range) for clinical trials using liposome-associated local anaesthetics.

Animals↗