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Biomedical subjects

A Gauthier

Publications and source records attributed to A Gauthier.

At least 19 recordsLinked to original sources
PubMed1995

HLA class II gene polymorphism in Tunisians.

The polymorphism of HLA class II genes (HLA-DRB, DQB, DPB) was investigated in 101 Tunisians using polymerase chain reaction. (PCR) amplification and reverse dot blot (RDB) hybridization. Allele and haplotype frequencies, as well as DRB1-DQB1 linkage disequilibria, were calculated. A total of 26 DRB1 alleles were detected and the most prevalent variant was DRB1*0301 with an allelic frequency at 21.87%. In the DR1 group, DRB1*0102 was most frequent than DRB1*0101. In the DR4 group, DRB1*0403 was the most common allele and was associated with DQB1*0402. Interestingly this DRB1-DQB1 association has not been observed in other populations. With regard to the DR8 group, DRB1*0804 was the unique variant detected, whereas with the DR13 specificity, the most common variant was DRB1*1303 in Algerians also. Although the DQB1 polymorphism analysis showed an allelic distribution very close to that observed in caucasoids, many DRB1-DQB1 associations which have not been reported in studies of other populations, were described. Finally at the DPB1 locus DPB1*1701 and *1301 allele frequencies distinguish clearly this Tunisian sample from a French caucasoïd panel of 83 subjects. In conclusion, a specific distribution of HLA components in terms of gene and haplotype frequencies characterizises this Tunisian population. This specific pattern may reflect the great ethnic diversity of this community. All these informations may be helpful in the future for HLA and disease association studies.

Gene Frequency↗
PubMed1992

Effects of cyclosporine and corticosteroids on bile secretion in the rat.

In order to study their effects on the bile secretion, cyclosporine and methylprednisolone were injected intravenously into rats at a dose of 10 mg/kg b.w. for 30 min. Methylprednisolone had no effect on bile secretion. Cyclosporine led to transient intrahepatic cholestasis characterized by decreased bile flow as well as a decrease of bile salts and cholesterol in bile. Phospholipid levels were not affected. Liver biopsy showed no particular anomaly. These findings suggest that the observed cholestatic reaction may be due to impairment of the metabolism of cholesterol into bile salts or of the conjugation of bile salts rather than to disturbances in bile secretion. After liver transplantation in humans, cholestasis associated with acute rejection or nonspecific cholestasis cannot be attributed directly to the effect of cyclosporine. Cholestasis can be offset by administering taurocholate at a dose of 10 mumol/min/kg b.w. in order to maintain bile salt and phospholipid levels high enough to ensure proper "vectorization" of cholesterol to bile.

Animals↗
PubMed1992

Clinical evaluation of a new triphasic oral contraceptive: norgestimate and ethinyl estradiol.

The safety and efficacy of the triphasic oral contraceptive agent containing norgestimate and ethinyl estradiol were evaluated in a 12-month study of 661 women. Excellent contraceptive efficacy was achieved, with two pregnancies ascribed to product failure in a total of 6,511 treatment cycles. The life-table predicted pregnancy rate was 0.57 per 100 woman-years of use. The overall and theoretical Pearl indexes were 0.55 and 0.37, respectively. Good cycle control was maintained in patterns similar to those noted in previous studies. The incidence of dysmenorrhea and premenstrual syndrome was sharply reduced. Side effects reported were typical of those associated with use of low-dose oral contraceptive agents. Acceptability was high compared with agents used previously by the subjects. Total cholesterol did not change but high-density lipoprotein cholesterol was significantly elevated at 3 and 12 months. There were no clinically significant changes in the parameters of hematology or blood chemistry tested.

Adolescent↗
PubMed1991

A group I intron in the chloroplast large subunit rRNA gene of Chlamydomonas eugametos encodes a double-strand endonuclease that cleaves the homing site of this intron.

During interspecific crosses between Chlamydomonas eugametos and Chlamydomonas moewusii, an optional group I intron of 955 base pairs (CeLSU.5) in the C. eugametos chloroplast large subunit rRNA gene undergoes a duplicative transposition event which is associated with frequent co-conversion of flanking cpDNA sequences. In the present study, we show that the basic protein of 218 amino acids encoded by CeLSU.5 could mediate the phenomenon of intron transposition, also called intron homing. We overexpressed the ORF specifying this protein in E. coli using expression vectors that contain a C. moewusii cpDNA sequence encompassing the intron homing site. The expression product was found to exhibit a double-strand DNA endonuclease activity that is specific for the homing site. This activity was detected in vivo by self-linearization of the expression plasmids.

Amino Acid Sequence↗
PubMed1991

Transfected trophoblast-derived human cells can express a single HLA class I allelic product.

The human trophoblast-derived JAR cell line, that does not express polymorphic HLA class I antigens even after IFN induction, can be stably transfected by genomic clones encoding the entire HLA-A2, -A3 and -B7 alpha-chain genes. The transfected genes were expressed at the cell surface in association with endogenous beta 2-microglobulin (shown by FCM analysis) as a single allelic product without reexpression of any endogenous class I gene (shown by 1D.IEF analysis). Furthermore, TNF-alpha and IFN-gamma, alone and synergistically, increase cell surface expression of transfected MHC class I/endogenous beta 2m heterodimers without induction of endogenous class I alpha-chain genes. These data show that the MHC class I-negative JAR human cell line might be used for transfections with the aim of establishing human cells expressing just one defined MHC class I allele for functional and regulatory studies. These findings are discussed in relation to the methylated status solely of endogenous class I alpha-chain genes in JAR cells and suggest that transfected class I genes are not regulated in the same fashion and, in particular, that constitutive and TNF/IFN inducible trans-acting regulatory factors able to bind to cis-promoter/enhancer sequences of class I DNA are likely to be present.

Alleles↗
PubMed1991

[Severe hemoptysis due to portal hypertension. Responsibility of acquired splenopulmonary shunt and treatment by proximal splenorenal anastomosis].

Hemoptysis is not considered as an hemorrhagic complication of portal hypertension. We report a patient with liver cirrhosis and portal hypertension who developed a hitherto unreported porto-pulmonary transdiaphragmatic collaterality many years after splenectomy. Life threatening hemoptysis complicated this unusual shunt after banal bronchitis. A proximal splenorenal shunt was performed and was completely effective at 26 months.

Anastomosis, Surgical↗
PubMed1991

[Multicentric clinical trial of a combination of 35 micrograms of ethinylestradiol and 2 mg of cyproterone acetate].

The authors report the results of an open multicentric study of 136 women treated by a combination of 35 micrograms ethinylestradiol and 2 mg cyproterone acetate for cutaneous manifestation of hyperandrogenism. No pregnancy occurred during the treatment of 12 months. Comparison between the last treated and non treated cycle showed a significant difference (p less than 0.001) in the severity of acne lesions regardless of their sites. General and gynaecological tolerance were excellent.

Acne Vulgaris↗
PubMed1990

Immunological aspects of mammary tumors in dogs and cats: a survey including own studies and pertinent literature.

Naturally occurring cancer in companion animals parallels cancer in man more closely than does experimentally induced cancer in inbred laboratory animals. In dogs and cats, as in man, a role for immune responses is indicated in the development of tumors. A survey is presented based on the literature and our own studies concerning the immunological and immunotherapeutic aspects of canine and feline mammary neoplasia. In dogs bearing mammary neoplasms, circulating immune complexes appear to play a negative role in the generation of effective antitumor immune responses. The functional role of peripheral blood lymphocytes and tumor-infiltrating lymphocytes in dogs and cats with mammary tumors is not yet fully established. No tumor antigen responsible for humoral or cellular responses has yet been identified. Extracorporeal perfusion of serum of dogs with mammary tumors and subcutaneous administration of mitomycin- and neuraminidase-treated autologous tumor cells are associated with improved prognosis. The opposite was true for i.v. treatment with BCG or Corynebacterium parvum vaccine in our study, in contrast to a previous report. A number of other treatment modalities in cats and dogs with mammary carcinomas failed to induce tumor regression. Canine and feline mammary carcinomas are good candidates for modern immunotherapeutic approaches.

Animals↗
PubMed1990

[Ultrasound-guided percutaneous ethanol injection of small malignant tumors of the liver. Results in 20 patients].

The effectiveness of percutaneous ethanol injection therapy was investigated in 20 patients with hepatocellular carcinoma (six cases), or hepatic metastases (twenty-five cases). 131 ethanol injections were performed between december 1987 and march 1990 for 30 lesions. Indications for this procedure included inadequate response to conventional treatment and tumor diameter less than 5 cm. Histopathologic examination, performed in all cases, showed that the tumor was completely necrotic in 16 cases, partially necrotic in 8 cases and not modified in 6 cases (one patient was not evaluable). Alpha-feto-protein and CEA levels were decreased in 12/17 cases. 16 patients were still alive at the end of the study (the mean follow-up period was 11.3 months). We conclude that ethanol injection may be a valuable treatment for small hepatic tumors.

Aged↗
PubMed1990

[Comparative study of fine needle aspiration and large caliber needle biopsy under echographic control for the diagnosis of abdominal tumors].

The aim of this study was to compare the results of fine needle aspiration (22 G) with large caliber needle biopsy (18 G) in patients suspected of having abdominal malignancy. From November 1988 to December 1989, 73 patients aged 32 to 78 years (mean 66 years), suspected sonographically of having hepatic malignancy (66 cases) or extrahepatic tumors (7 cases), underwent ultrasonography guided percutaneous fine needle aspiration (22 G) and biopsy with a large caliber needle (18 G). There were no complications. Overall sensitivity for diagnosis of malignancy was significantly better (p less than 0.01) with 18 G needle biopsies (91.2 percent) than with fine needle cytology (71.4 percent). Specificity was 100 percent. The distinction between primary and secondary malignant tumor was possible in 87.5 percent with the large caliber needle and in only 42.9 percent with the fine needle (p less than 0.001). Histological findings were adequate hepatic metastases in 86.5 percent with the 18 gauge needle and in 51.4 percent with the 22 gauge needle (p less than 0.001). In the 7 extra-hepatic tumors, the 18 G biopsy was always positive whereas fine needle cytology was positive in only 5 out of 7 cases. Correct diagnosis for benign diseases was possible in 7 out of 10 cases with the large caliber needle whereas the fine needle cytology was always negative. These results show the superiority of large caliber needle (18 G) compared to fine needle (22 G) guided punction for both diagnosis of malignancy and origin of the tumor. Complications did not occur more frequently than with fine caliber needles.

Adult↗
PubMed1990

[Endoscopic detection of dysplasia and subclinical cancer of the esophagus. Results of a prospective study using toluidine blue vital staining in 100 patients with alcoholism and smoking].

In spite of the development of upper digestive tract fiberoptic endoscopy (FE) within the last 10 years, early detection of esophageal carcinoma (EC) is rare except in certain high-risk groups such as patients with head and neck cancers. The aim of this study was to assess the value of a meticulous histoendoscopic examination with vital toluidine blue (TB) staining in all alcohol and tobacco abusers undergoing FE for any reason except dysphagia. In 18 months, 100 patients (90 men, 10 women) who were over 40 years old and who consumed more than 80 g of alcohol and 20 g of tobacco per day underwent FE. No patient had a history of head and neck or esophageal cancer. FE was decided in 48 patients for epigastric pain, in 28 for esophageal varices, in 8 for weight loss, in 8 for anemia, in 7 for peptic disease, and in 1 for diarrhea. Staining with TB was carried out at the end of the examination and two routine biopsies were obtained 5 cm above the lower esophageal sphincter. Specimens were obtained from each abnormal area (TB + or TB -). Clinical ENT examination was recommended for all patients. Two esophageal carcinomas (1 microinvasive, 1 in situ) and 15 cases of dysplasia were detected. Dysplasia was classified as severe in 1 case, moderate in 9 cases, and mild in 5 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

An optional group I intron between the chloroplast small subunit rRNA genes of Chlamydomonas moewusii and C. eugametos.

We report the presence of a 402 bp group I intron in the chloroplast small subunit (SSU) rRNA gene of Chlamydomonas moewusii. The intron in inserted within the highly conserved '530 loop', at a site corresponding to positions 531-532 of the E. coli 16rRNA. Residues surrounding the insertion site almost certainly play an important role in ribosomal proofreading function as they proved to be protected by tRNAs in E. coli 16S rRNA (Moazed and Noller 1986; Stern et al. 1986). The C. moewusii intron revealed a secondary structure model which differs substantially from those of the typical subgroup IA and IB introns. This model, however, shows striking similarities with the structures of the C. reinhardtii chloroplast 23S rRNA gene intron (Rochaix et al. 1985), the S. cerevisiae mitochondrial COB3 intron (Holl et al. 1985) and the three introns of phage T4 in the nrdB, td and sunY genes (Shub et al. 1988). The SSU rRNA gene intron is absent from C. eugametos, an alga that is interfertile with C. moewusii. The presence/absence of the intron account for a 390 bp restriction fragment length polymorphism between the two algal SSU rRNA genes, a polymorphic locus that is strictly co-inherited with a tightly linked streptomycin resistance mutation (sr-2) in interspecific hybrids between the two algae.

Base Sequence↗
PubMed1989

Treatment of duodenal ulcer with rioprostil: a randomized multicentre double-blind study.

The effectiveness of rioprostil, 300 micrograms b.d. is evaluated in evolutive duodenal ulcer in a double-blind study in five French and North African centres. A total of 115 patients are included in the study (57 in the rioprostil group and 58 in the placebo group). After a 4-week treatment period, a significantly higher endoscopic healing rate is observed in the rioprostil group (57%) compared with the placebo group (33%) (p less than 0.01). The mean time with abdominal pain is significantly lower in the rioprostil group (5.6 +/- 4.4 days) compared to the placebo group (12.7 +/- 5 days) (p less than 0.001). Clinical and biological tolerance is excellent. The only side effect is diarrhoea (3.5% in the rioprostil group). In only one case does diarrhoea necessitate cessation of treatment. Rioprostil, 300 micrograms b.d., is thus effective in the treatment of developing duodenal ulcer.

Anti-Ulcer Agents↗
PubMed1989

[Treatment of minor hepatic tumors with ultrasonically guided percutaneous injection of absolute alcohol. Results in 8 patients].

The effectiveness of ultrasonically guided percutaneous ethanol injection therapy was investigated in 8 patients who had hepatocellular carcinoma (two cases), hepatic metastases from colorectal carcinoma (five cases) and hepatic metastasis from breast carcinoma (one case). Tumor diameter was less than 5 cm in all cases. Fifty-nine ethanol injection were performed for 11 lesions. Histopathologic examination, performed in all cases, showed that the tumor was completely necrotic in 4 cases, partially necrotic in 3 cases and unchanged in 4 cases. Serum alphafetoprotein and carcinoembryogenic antigen decreased in 5 out of 8 cases. Seven patients were still alive at the end of the study with a mean follow-up period of 10.7 months. We conclude that ethanol injection may be a valuable treatment for small hepatic tumors.

Administration, Cutaneous↗