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J Lebeau

Publications and source records attributed to J Lebeau.

At least 55 records · Page 3Linked to original sources
PubMed1995

Cardiopulmonary bypass with circulatory arrest in swine: echocardiographic evaluation of left ventricle function and pulmonary vein flow.

Complete two-dimensional echocardiography and Doppler flow studies were performed on 17 swine as part of an experimental protocol involving cardiopulmonary bypass with circulatory arrest. Indices of left ventricular function and pulmonary vein morphology and flow velocity were taken before (17/17) and after bypass (11/17). A total of 70 measurements were available for analysis. Doppler flow velocity within the right pulmonary vein was 0.5 +/- 0.06 m/sec and was 0.52 +/- 0.05 m/sec in the left pulmonary vein. The swine were found to have a marked reduction in left ventricle function compared with that in previous reports, though no statistical difference was seen between pre- and post-cardiopulmonary bypass studies (preoperative shortening fraction was 21 +/- 5% and ejection fraction was 41 +/- 8%; postoperative shortening fraction was 23 +/- 5% and ejection fraction was 42 +/- 7%). Swine with shortening and ejection fractions of < 20% were found to have more unstable hemodynamics during cardiopulmonary bypass.

Animals↗
PubMed1995

[Unusual use of a tissue expander].

Postpneumonectomy syndrome is a rare but serious complication. Mediastinal shift leads to compression of the remaining main bronchus. Repositioning of the mediastinum in the midline allows partial or total recovery. To maintain mediastinal position, the pneumonectomy space must be filled by a tissue expander.

Bronchi↗
PubMed1994

Antisense oligonucleotides adsorbed to polyalkylcyanoacrylate nanoparticles specifically inhibit mutated Ha-ras-mediated cell proliferation and tumorigenicity in nude mice.

Ras oncogenes owe their transforming properties to single point mutations in the sequence coding for the active site of the p21 protein. These mutations lead to changes in cellular proliferation and induce tumorigenic properties. Point mutations represent a well-defined target for antisense oligonucleotides that can specifically suppress the translation of the targeted mutant mRNA. We show that the stability and cellular disponibility of antisense oligonucleotides can be markedly improved by adsorption to polyalkylcyanoacrylate nanoparticles. Nanoparticle-adsorbed antisense oligonucleotides directed to a point mutation (G-->U) in codon 12 of the Ha-ras mRNA selectively inhibited the proliferation of cells expressing the point-mutated Ha-ras gene at a concentration 100 times lower than free oligonucleotides. In addition they markedly inhibited Ha-ras-dependent tumor growth in nude mice after subcutaneous injection. These experiments show that inhibition of ras oncogenes by antisense oligonucleotides can block tumor development even though ras oncogenic activation might be an early event in tumor progression.

Adsorption↗
PubMed1994

Chromosomal instability and alterations of telomeric repeats in irradiated human fibroblasts.

In recent years, evidence has been presented suggesting that genomic instability can appear several generations after cellular exposure to radiations. Kadhim et al. (1992) have shown that irradiation by alpha-particles of Pu238 (LET = 120 keV/microns) induce a transmissible instability in mouse haematopoietic cells. Working with human dermis fibroblasts irradiated by heavy ions in a large range of LETs (386-13,600 keV/microns), we demonstrated that an instability could also be acquired by human cells and that particular chromosomes (13, 16, 1) were recurrently involved in telomeric associations (Sabatier et al. 1992). This instability resulted in specific chromosome imbalances and in a particular monosomy 13 (Martins et al. 1993). In this study, we wanted to determine whether telomeres are shortened with the appearance of the chromosomal instability. Our results show no drastic shortening of the mean length of telomeres by Southern blot. By in situ hybridization we are looking to see if chromosomes specifically involved in instability have alterations of the telomeres. We have observed large variations of the hybridization signal of individual telomeres with no telomeric sequences detectable at the junction of end to end associations.

Cell Transformation, Neoplastic↗
PubMed1994

[The nose: representation and symbolism].

The nose is a primordial element in the facial recognition among the human species. This privileged place, confirmed by experimental psychology, finds a professional application in the creation of the photofit. The physiognomonist drift, that flourished during the last century, lacked a scientific basis and gradually gave way. On the other hand, it is interesting to observe the artist's representations of the nose: except for the realistis school the nose is upsetting. It is therefore either stereotyped or deleted. As for the caricaturist, he illustrates the nose shamelessly. This representation is certainly related to the symbolic force of the nasal appendage, not only a vector of diverse and variable odours but also a passage for the spirit and to the heart. The nose is therefore a significative element of relation, of contact and of expression.

Art↗
PubMed1993

[Congenital cutaneous aplasia. Apropos of 3 new cases located in the vertex].

Aplasia cutis congenita is a rare malformation characterized by absence of skin. We report three new cases, localized on the vertex with one appearing as a familial form and requiring an emergent surgical repair with a favorable outcome. After a review of the literature, the authors discuss nosological aspects and etiological problems which are still not resolved. It seems that vascular differentiation of the skin could play an associated role. As regards of treatment, different attitudes are possible and are exposed, with a preference for surgery which is the method of choice for the authors.

Abnormalities, Multiple↗
PubMed1992

[Mountain sports: their role in 2200 facial injuries occurring over 4 years at the University Hospital Center in Grenoble].

Injuries caused by mountain sports account for many of the injuries admitted to the University Hospital of Grenoble. Out of 4,490 traumas, 470 were injuries sustained during the practice of mountain sports. While the frequency of these accidents does not evolve much, the etiological distribution depends on fashion. Thus an increasing number of lesions caused by cross-country biking has been noted during the past two years. We find it urgent to propose protective measures adapted to this new sport.

Accidents↗
PubMed1991

Drainage of the scalp by the superficial temporal vein: surgical implications.

The arrangement of the veins of the scalp is not well-known. The drainage of the scalp by the superficial temporal v. was studied in 68 specimens dissected from unembalmed cadavers. After prolonged contraflow irrigation, the whole of the venous network drained by the trunk of the superficial temporal v. was injected from either side with latex. Depending on the method chosen to demonstrate the venous network, whether by direct observation or corrosion, the latex was stained with Evans' blue or with Latexol. The superficial temporal a. was also prepared by injection-corrosion in 16 cases. The diameter of the trunk of the superficial temporal v. in its preauricular portion was estimated as between 1.1 and 1.6 mm. Nine different types, classified by frequency, were recognised in the arrangement of the affluents of the superficial temporal v. In every case there was a main parietotemporal collector continued as the trunk of the superficial temporal v. The affluents joining the main collector varied in number (from 8 to 1) and in arrangement. Their anastomoses with the veins adjacent to the superficial temporal v. were numerous. The density of the secondary branches varied greatly with individuals. They were sometimes totally absent, particularly in the fronto-temporal region. Usually, the main collector was of sufficient caliber for microsurgical use and its course followed that of the parietal branch of the superficial temporal a., but in 4% of cases the main collector was too narrow to be so used and in 8% of cases its course did not follow that of the parietal branch of the superficial temporal a.(ABSTRACT TRUNCATED AT 250 WORDS)

Cadaver↗
PubMed1991

[Superficial temporal venous drainage and its risks. Surgical implications].

Certain failures in scalp surgery due to defective venous drainage have led the authors to reconsider the classical anatomical data concerning the temporofrontal venous network. The study conducted in the anatomy laboratory concerned 110 superficial temporal territories injected with various coloured polymerizable substances in order to visualize this network in the skin. This study enabled the authors to describe nine types of venous drainage, the surgical implications of which are discussed.

Blood Circulation↗
PubMed1991

Constitutive overexpression of a 89 kDa heat shock protein gene in the HBL100 human mammary cell line converted to a tumorigenic phenotype by the EJ/T24 Harvey-ras oncogene.

The non tumorigenic human mammary cell line HBL100 has been transformed by the EJ/T24 human bladder carcinoma Harvey(Ha)-ras oncogene. Six cell lines were established from transformed colonies. They all expressed a high level of the ras oncogene and were tumorigenic in athymic nude mice. During an in vivo passage in animals, tumour cells presenting a growth advantage were selected, and some of the tumours revealed an amplification of the transfected ras sequences. Using this model of human cell transformation, we have isolated a cDNA clone corresponding to a heat shock protein gene (hsp89 alpha). This gene, normally transcribed at a higher rate in response to serum stimulation, was found to be constitutively overexpressed in ras-transformed HBL100 cells. In contrast, a closely related hsp gene (hsp89 beta), remained sensitive to serum stimulation, in both untransformed and ras-transformed HBL100 cells. Thus, the regulation of the expression of the hsp89 genes, upon serum stimulation, involves ras-dependent and ras-independent pathways. Constitutive overexpression of the murine homolog of the hsp89 alpha was observed in NIH3T3 cells transformed by the three ras oncogenes, but not with some other oncogenes. Therefore, alteration of the hsp89 alpha gene expression is not a general characteristic of transformed cells, but seems to be linked to ras transformation.

Animals↗
PubMed1990

[Three-dimensional imaging in plastic surgery. Application to the carpal bones and skull].

Since 1987, the authors have developed three-dimensional (3D) imaging of the carpus. This new application of imaging allows spatial visualization of the complex shapes of the carpal skeleton from all angles and from all illuminations. The development of this technique should lead to a better understanding of the intimate physiology of the carpus, allowing the construction of a model of the wrist enabling precise planning of operative procedures. It also helps to elucidate complex pathological images which are sometimes difficult to interpret on computed tomography scans. In parallel, the same process has been developed for the skull. It is particularly useful in cranio-facial surgery, especially in congenital deformities. Progress in this technique should allow surgical simulation on a video screen in the very near future.

Carpal Bones↗
PubMed1990

Radiation osteitis of the clavicle following radiotherapy and radical neck dissection of head and neck cancer.

The bone alterations in the region of the clavicle (3 cases) are similar to those we have observed and described elsewhere in the skeleton i.e., the mandible, maxillary and ethmoid bones. Rarefaction is the result of three different types of bone destruction: osteoclasia, a kind of osteocytic osteolysis only observed after irradiation and obviously related with infection, and a pure demineralization of the osseous tissue by contact with pus. Reconstruction processes, although unable to prevent spontaneous fracture, are also present and correspond to islets of chondroid tissue surrounded by lamellar bone. However, these recently deposited calcified tissues are already necrotic since most of their lacunae are empty.

Clavicle↗
PubMed1989

Molecular cloning of the 25 kbp region upstream of exon 0 of the human Ki-ras oncogene and its conservation in transformed mouse NIH 3T3 cells.

Human sequences associated with the Ki-ras oncogene of the mammary tumour cell line, H-466B have been cloned from a tertiary NIH3T3 mouse transfectant. These sequences are located 5' upstream of exon 0 of the Ki-ras oncogene, span over 25 kbp of DNA and are conserved in half of the primary transfectants obtained with the Ki-ras gene of different types of tumours. No gross alterations were observed in the sequences upstream of the Ki-ras gene. The partial or total deletion of these sequences in the other half of primary transformants argues that they are not absolutely required for the transforming activity of the Ki-ras oncogene. The even distribution of the human-mouse junction points in primary transformed mouse cells suggests the absence of a specific region of recombination in the 5' flanking region of Ki-ras.

Animals↗
PubMed1988

Interferon-beta 2 (BSF-2) mRNA is expressed in human monocytes.

We previously have reported the presence of interferon-beta 2 (IFN-beta 2) mRNA in PHA-stimulated human peripheral blood leukocytes (PBL), as well as in nonstimulated cells, although at a lower level. The IFN-beta 2 cloned from a leukocyte library appeared to be similar to that of the fibroblast IFN-beta 2 gene first described in fibroblasts. To assess the nature of the cell population in which the synthesis of IFN-beta 2 takes place, PBL were fractionated in adherent and nonadherent cells. The antiviral activity of the culture supernatants of adherent cells was characterized as the IFN-beta type by neutralization with polyclonal antibodies raised against purified fibroblast IFN-beta 2. IFN-beta 2 mRNA was observed in enriched monocyte populations and accumulated very rapidly, peaking at 2.5 h. RNA extracted from these cultures encoded in a reticulocyte lysate a protein immunoprecipitated by the anti-IFN-beta 2 antiserum. In addition, IFN-beta 2 secreted in monocyte supernatants also was immunoprecipitated by the specific antiserum and was able to compete with the fibroblast IFN-beta 2, suggesting a strong similarity between the fibroblast and monocyte proteins.

Cell Adhesion↗
PubMed1987

Amplification of the epidermal growth factor receptor gene in the BT20 breast carcinoma cell line.

Southern blot-hybridization analysis of 10 breast carcinoma cell lines demonstrated an amplification of the epidermal growth factor (EGF) receptor gene in the BT20 cell line. The gene was amplified 10- to 14-fold when compared to the level seen in human placental DNA. Northern blot analysis indicated an increased level of transcription in this cell line which probably accounts for the high level of the EGF receptor reported in the BT20 cell line.

Breast Neoplasms↗
PubMed1987

Two adjacent mutations at position 12 activate the K-ras2 oncogene of a human mammary tumor cell line.

Among 10 human mammary tumor cell lines analyzed for transforming genes by transfection of NIH 3T3 cells, one carcinoma cell line, H-466B, established from an ascitic effusion of a woman with an adenocarcinoma of the breast was scored as positive. The transforming gene was identified as the K-ras2 oncogene. Nucleotide sequencing of exons 1 and 2 of the activated gene revealed two adjacent G----T transversions at the first and second position in codon 12 leading to the replacement of the normally encoded glycine by a phenylalanine. Since the phenylalanine substitution had never been observed in any type of tumor, this raises the question about the frequency as well as the cell type specificity of this K-ras2 activation in mammary tumors.

Amino Acid Sequence↗