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C Laurent

Publications and source records attributed to C Laurent.

At least 109 records · Page 6Linked to original sources
PubMed1998

[The value of peak expiratory flow after exertion].

We have measured peak expiratory flow after a 15-20 minutes run in cold weather in 777 pupils of the sixth year of Val-de Marne. The aim of this measurement was to validate the peak expiratory flow as a means of detecting the early state of respiratory anomalies. A questionnaire was distributed to 920 families before the endurance test. A fall of peak expiratory flow greater than 15% was seen in 77 pupils (9.9%). Twelve of 35 asthmatic pupils who participated in the run lowered their peak expiratory flow compared to 65 out of 742 who were not known as asthmatic (chi 2 = 24; p < 0.001). Complementary respiratory function tests could not be obtained in a systematic fashion so the significance of this lowering remains difficult to interpret. In our study, the level of scholastic delay in asthmatics was close to that of the non asthmatics. The role of the service for the promotion of health for the benefit of pupils (SPSEFE) concentrates as much on the early stages as on the follow up and education of young asthmatics at school in partnership with the families and the treating physician. Writing out a welcoming individualised protocol enable young asthmatics the best possible integration into school.

Asthma↗
PubMed1998

[Anorectal reconstruction by coloperineal anastomosis and dynamic double graciloplasty after abdomino-perineal resection].

UNLABELLED: The aim of this study was to assess the technical and functional results of total anorectal reconstruction with double dynamic graciloplasty after abdominoperineal resection (APR). PATIENTS AND METHODS: From May 1995 to December 1996. 10 patients (6 males and 4 females), with a mean age of 54 years (range 39-74), underwent anorectal reconstruction for low rectal adenocarcinoma. All patients had preoperative radiotherapy and six had postoperative chemotherapy. The surgical procedure was performed in three stages: 1) APR, coloperineal anastomosis, double graciloplasty and ileostomy; 2) three months later, implantation of stimulator and leads; 3) after a two-months training period, the stoma was closed. RESULTS: There was no postoperative mortality. Early and late morbidity occurred in 5 patients: 2 colonic fistulas, 1 necrosis of colon, 1 ileostomy prolapse, 1 neosphincter stenosis, 1 sepsis of stimulator. No patient had recurrence of the disease (mean follow-up 16 months), but two patients died at 3 and 8 months, respectively from anorexia and pulmonary embolism. Seven patients were available for evaluation (2 fistula, 1 death). Before training, the resting pressure and the squeeze pressure were 30 and 175 cm H2O respectively. At the time of evaluation, the electrical stimulated pressure was 95 cm H2O. Six of these 7 patients were continent (5 with spontaneous defecation, 1 with enemas) and 1 was incontinent. CONCLUSIONS: Anorectal reconstruction with dynamic graciloplasty can be an alternative to permanent colostomy for selected patients after APR. However, there is a high morbidity and the quality of life of the patients must be evaluated.

Adenocarcinoma↗
PubMed1997

Monitoring of occupational exposure to epichlorohydrin by genetic effects and hemoglobin adducts.

The present work is focused on the determination of in vivo doses and studies of genetic effects in workers exposed to epichlorohydrin (ECH). The studied endpoints were hemoglobin (Hb) adducts, frequencies of hprt mutants, micronuclei in cytochalasin B blocked binucleated lymphocytes, sister chromatid exchanges (SCE) and high frequency cells (HFC). Blood samples were collected from office clerks and ECH exposed factory workers at an industrial plant in Germany. The workers were exposed to 0.11-0.23 ppm ECH in the air 45 h per week and to 0.2-2.6 ppm for 3 h per week. Some Swedish non-exposed subjects were also used for Hb adduct measurements. The genetic data, HFC and SCE, showed a significant difference between exposed and unexposed donors. In contrast to earlier studies on SCE, no impact of smoking was observed. Effects on micronuclei were on the borderline of significance, whereas there was no effect for HPRT mutants. The average Hb adduct level was higher in exposed than in non-exposed donors, although the difference was only significant when the exposed group was compared to Swedish controls. Smoking gave significantly increased adduct levels. The absence of significant correlations between individual data for Hb adducts and genetic effects, may be explained by the different periods of time covered by the responses in these endpoints. Whereas Hb adducts reflect the exposure during up to 4 months (i.e. the life span of human erythrocytes), the SCE, and particularly the HFC, seem to accumulate for years in a long-lived fraction of T-lymphocytes without DNA repair. Thus, the adduct data does not reflect the exposure backwards in time unless it can be shown that exposure conditions have remained unchanged. The origin of the background adduct levels in non-smoking control persons is at present not known.

Adult↗
PubMed1997

Early onset of immunoglobulin heavy chain gene rearrangements in normal human bone marrow CD34+ cells.

To characterize early B-cell precursors in humans, we correlated immunoglobulin heavy chain (IgH) gene rearrangement status with the CD34, CD19, and CD10 cell surface markers. Highly purified adult bone marrow (BM) cell fractions were obtained by two successive rounds of flow cytometric cell sorting, and IgH rearrangements were analyzed by polymerase chain reaction (PCR) amplification. Complete VDJH rearrangements were observed in the CD34+ CD19+ fraction, but not in the more immature CD34+ CD19- fraction. About one quarter of these rearrangements had an open reading frame, thus potentially permitting the synthesis of a mu chain. Partial DJH rearrangements were detected in both CD34+ CD19+ and CD34+ CD19- subsets, although they were less abundant in the latter. When triple labeling was used to better characterize the CD34+ CD19- population, DJH rearrangements were found to be present in the CD34(+) CD10+ CD19- fraction, but not in the more primitive CD34+ CD10- CD19-. These results indicate that IgH gene rearrangements occur in CD34+ BM cells and that they initiate in immature progenitors expressing the CD10, but not yet the CD19 surface antigen. Finally, the presence of IgH gene rearrangements in CD34+ BM cells provides a useful marker of clonality to evaluate the possible involvement of these cells in various B-cell lymphoid malignancies.

Adult↗
PubMed1997

High-performance liquid chromatography/electrospray mass spectrometry for the analysis of modified bases in DNA: 7-(2-hydroxyethyl)guanine, the major ethylene oxide-DNA adduct.

A method was developed for the analysis of 7-(2-hydroxyethyl)guanine (7HEG), the major DNA adduct formed after exposure to ethylene oxide (EO). The method is based on DNA neutral thermal hydrolysis, adduct micro-concentration, and final characterization and quantification by HPLC coupled to single-ion monitoring electrospray mass spectrometry (HPLC/SIR-ESMS). The method was found to be selective, sensitive, and easy to handle with no need for enzymatic digestion or previous sample derivatization. Detection limit was found to be close to 1 fmol of adduct injected (10(-10) M), thus allowing the detection of approximately three modified bases on 10(8) intact nucleotides in blood sample analysis. Quantification results are shown for 7HEG after calf thymus DNA and blood exposure to various doses of EO, in both cases obtaining clear dose-response relationships.

Animals↗
PubMed1997

Association of DNA polymorphism in the first intron of the tyrosine hydroxylase gene with disturbances of the catecholaminergic system in schizophrenia.

We examined whether there are clinical or biological differences in chronic schizophrenic patients sharing a rare variant allele (a perfect ten tetranucleotide repeats allele of the human TH01 microsatellite) in the tyrosine hydroxylase (TH) gene. For that purpose, clinical parameters (PANSS subscores) and plasma measurements (homovanillic acid and 3-methoxy-4-hydroxy-phenylglycol (MHPG)) were analyzed in five schizophrenic patients sharing the rare allele and 19 schizophrenic patients who did not possess this allele. The mean concentration of plasma HVA and plasma MHPG were significantly lower in the group of schizophrenic patients sharing the rare allele. No other group differences were observed between both groups. These results suggest that this TH gene polymorphism may be associated with disturbances of the catecholaminergic pathway.

Adult↗
PubMed1997

Extracellular matrix components reflect the dynamics of a healing tympanic membrane perforation--a histochemical study.

Extracellular matrix components have hitherto been sparsely studied in tissue repair processes. In this study, the distribution of hyaluronan (HYA), fibronectin, and five chondroitin sulfate glycosaminoglycans (GAGs) was analysed in healing tympanic membrane (TM) perforations of rats, at different time points, using a HYA-binding protein probe and six monoclonal antibodies (MAbs). Hyaluronan appeared, the first day, around migrating squamous epithelial and inflammatory cells in the perforation borders and close to dilated vessels at the malleus handle. Accumulated HYA persisted in the thickened perforation rim until closure of the perforation, then it slowly disappeared from the healed TM area. Fibronectin immunoreactivity occurred around proliferating cells in the perforation edge and around collagen bundles in the connective tissue. The MAbs for chondroitin sulfate GAGs rendered specific, constant immunostaining patterns throughout the healing process. Unsulfated chondroitin, chondroitin-4-sulfate and chondroitin-6-sulfate were present in small amounts in the connective tissue surrounding collagen fibres and fibroblasts. The staining for native chondroitin and dermatan sulfate was most pronounced in the epithelial layers, in particular the squamous epithelium and its keratin layer, whereas the loose connective tissue was left unstained. After closure of the TM perforations, the immunoreactivity for unsulfated chondroitin, native chondroitin and dermatan sulfate increased in the scar tissue. It is concluded that HYA is abundant in early stages of healing of TM perforations, whereas fibronectin, unsulfated chondroitin, chondroitin-4 and 6-sulfate are constantly present in small amounts during the healing process. Unsulfated chondroitin, native chondroitin and dermatan sulfate increase in the healed TM area.

Animals↗
PubMed1997

Detection of two new polymorphic sites in the human interleukin-1 beta gene: lack of association with schizophrenia in a French population.

The pathogenesis of schizophrenia might involve abnormal development of the human brain. Interleukin-1 beta is a cytokine implicated in the development of the central nervous system and therefore its gene is a candidate gene in schizophrenia. Polymorphisms within the coding sequence and the 3'UTR of the IL1 beta gene were searched for using PCR-SSCP. Two polymorphisms, 1B-175/1B-173 and 1B-1765/1B-1763 were found in addition to the previously published TaqI site. Furthermore, a mutant was found in codon 106 (exon 5) of the IL1 beta gene located next to the published polymorphism at the TaqI site and abolishing this site. This novel mutation encodes an Asp in place of an Asn and was only observed in one patient in our French population. Association studies were conducted with the polymorphisms 1B-175/1B-173 and TaqI. There was no allelic or genotypic association between either of the two polymorphisms and schizophrenia. In our population, there is no evidence that the IL1 beta gene is involved in schizophrenia.

Adult↗
PubMed1997

Local recurrence of low rectal cancer after abdominoperineal and anterior resection.

BACKGROUND: The aim of this retrospective study was to compare the risk of local recurrence between two groups of patients with low rectal cancer treated by either abdominoperineal resection (APR) or anterior resection. METHODS: From 1982 to 1992, 106 low rectal cancers (tumour situated 3-8 cm from the anal verge), of Dukes stage B and C were treated by curative surgery, 52 by APR and 54 by anterior resection. Mean follow-up was 60 months after APR and 50 months after anterior resection. RESULTS: The local recurrence rate of low rectal cancer was 16 of 52 (31 per cent) after APR and 15 of 54 (28 per cent) after anterior resection. The risk of local recurrence in univariate and multivariate analysis was not associated with clinical and histological variables, nor with the type of intervention. CONCLUSION: Sphincter-saving resection can be performed for low rectal cancer without an increased risk of local recurrence.

Anastomosis, Surgical↗
PubMed1996

Characterization and immunohistochemical localization of the glycoconjugates of the rabbit bladder mucosa.

An impairment of the mucosal glycoconjugates could be an important factor in the development of bladder disorders such as interstitial cystitis. However, very little definitive biochemical information is available on the glycoco-jugate components of the mammalian bladder mucosa. In this-study, the mucosa from metabolically radiolabeled rabbit bladder was separated, delipidated, and digested with protease, and the released glycosaminoglycans and glycopeptides were fractionated. About 80 and 36% of the nondialyzable tritium and 35S activities, respectively, was associated with the sialoglycopeptide fractions. The balance of the total tritium activity in the protease digest was in glycosaminoglycans identified as hyaluronan, chondroitin sulfates, and heparan sulfate. Immunohistochemical examination using anti-heparan sulfate antibodies, including one against mouse syndecan-1, indicated the presence of heparan sulfate proteoglycan in the epithelium. In contrast, there was no significant staining of the bladder epithelium with anti-chondroitin-4- and 6-sulfate antibodies or hyaluronan-binding protein. The lamina propria and muscle layers showed strong staining with anti-chondroitin-4-sulfate antibody and hyaluronan-binding protein and weak staining with anti-chondroitin-6-sulfate antibody. The insignificant levels of glycosaminoglycans in the glycocalyx of bladder mucosa epithelium suggest that glycosaminoglycans may be less important than other glycoconjugates in maintaining normal epithelial function and in bladder disorders such as interstitial cystitis.

Animals↗
PubMed1996

Association study between schizophrenia and monoamine oxidase A and B DNA polymorphisms.

Monoamine oxidases (MAO) A and B, which are encoded by two distinct genes located on the human X chromosome, are both involved in the oxidative metabolism of dopamine. Decreased levels of platelet MAO-B activity has been reported in patients with schizophrenia and genetic variation in MAO activity had been proposed as a significant factor in the etiology of this disease. We carried out an association study using two intragenic polymorphisms within the MAO-A and MAO-B genes in 110 schizophrenic patients and 87 control subjects. For each polymorphic marker, no significant difference in allelic frequencies was observed between patients and controls. Nevertheless, a trend toward an association between allele 1 of the MAO-B gene and paranoid schizophrenia was found. Our results do not support the hypothesis that inherited variants of MAO genes might play a major role in a genetic predisposition to schizophrenia. Since several previous reports found a low MAO-B platelet activity in patients with paranoid schizophrenia, the identification of polymorphisms related to enzyme activity would be useful.

Adolescent↗
PubMed1996

Complete TCR-delta rearrangements and partial (D-J) recombination of the TCR-beta locus in CD34+7+ precursors from human cord blood.

In the neonatal human thymus, early immature precursors co-express CD34 and CD7 cell surface Ags, and we have recently shown that its most primitive CD34+7+1- fraction includes TCR-beta-rearranging cells. Bone marrow and cord blood also contain a CD34+7+ population. Although this population is heterogeneous in terms of both phenotype and differentiation capacities, it may include T cell-committed thymus colonizing precursors (prothymocytes). Recently, it has been shown in the mouse that initiation of TCR-beta rearrangements is not restricted to early thymocytes. In the present study, we examined the TCR-beta and TCR-delta rearrangement and transcription status of cord blood CD34+7- and CD34+7+ subpopulations. RNA and DNA were isolated from these cell subsets purified by two consecutive rounds of fluorescence-activated cell sorting from CD3-depleted cord blood cells. Using D-J(beta) or V-J(beta) primer sets and genomic DNA PCR amplification, we showed that CD34+7+, but not CD34+7-, contained D-J(beta) rearrangements without concomitant V-D(beta) recombination. These partial TCR-beta rearrangements within CD34+7+ progenitors were also confirmed at the transcriptional level. Furthermore, whereas none of the CD34+ cord blood cell fraction expressed TCR-alpha transcripts, mature V(delta)1-C(delta) mRNA could be amplified from the CD34+7+ subset. The TdT gene was also transcriptionally active in CD34+7+ cells, thus confirming their lymphoid progenitor content. These data indicate that cord blood CD34+7+ cells, like CD34+7+1- neonatal thymocytes, can initiate TCR-beta gene recombination, reinforcing the idea that T cell commitment may occur before prothymocyte migration to the thymus.

Animals↗
PubMed1996

Hyaluronan localization in the rabbit larynx.

BACKGROUND: The larynx is a complex organ composed of different connective tissue elements. So far, the extracellular matrix of the larynx has not been thoroughly described. Hyaluronan is a matrix polysaccharide with physicochemical effects and biological cell functions in soft connective tissues. METHODS: The histochemical distribution of hyaluronan (hyaluronic acid, hyaluronate) was studied in tissue sections from various levels of the rabbit larynx by means of a hyaluronan-binding protein and avidin biotin peroxidase staining. Microwave-aided fixation was used to retain the extracellular location of hyaluronan. RESULTS: Hyaluronan accumulated chiefly in the subepithelial lamina propria and in the connective tissue enclosing striated muscle fibres of the thyroarytenoid muscle and vocalis muscle. This localization contrasted sharply with the weak staining for hyaluronan in muscles external to the thyroid cartilage. Intensive staining for hyaluronan was found in perivascular and periglandular connective tissue, as in the vacuoles of the hyaline cartilage of the thyroid, cricoid and arytenoid cartilages, and to a lesser extent in the lacunae of the chondrocytes and in the perichondrium of the elastic cartilage of the epiglottis. CONCLUSIONS: Hyaluronan was heterogenously distributed in the rabbit larynx. It was abundant in intrinsic laryngeal muscles performing small, precise, and rapid movements and in the subepithelium at the glottic level, where it may facilitate mucosal movements. The abundant hyaluronan in the subglottic region may be involved in the control of vascular leakage and edema formation.

Animals↗