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Biomedical subjects

F Dumas

Publications and source records attributed to F Dumas.

At least 19 recordsLinked to original sources
PubMed1995

Haematogenous dissemination of prostatic epithelial cells during radical prostatectomy.

Radical prostatectomy is one treatment for organ-confined prostatic adenocarcinoma. Dissemination of malignant prostatic cells after radical prostatectomy could be partly due to prostate manipulation during dissection. We confirmed by assay of prostate-specific membrane antigen by reverse-transcription nested PCR that prostate manipulation seeded prostatic epithelial cells in the general circulation in 12 of 14 consecutive patients operated on for organ-confined prostate adenocarcinoma. Our results suggest that surgeons should approach radical prostatectomy with care to avoid seeding from the prostate gland. Antiandrogen therapy might reduce the haematogenous spread of prostatic cells during radical prostatectomy.

Adenocarcinoma↗
PubMed1995

Identification of EaeA protein in the outer membrane of attaching and effacing Escherichia coli O45 from pigs.

We have previously reported that the production of attaching and effacing lesions by Escherichia coli O45 isolates from pigs is associated with the eaeA (E. coli attaching and effacing) gene. In the present study, expression of the EaeA protein, the eaeA gene product, among swine O45 E. coli isolates was examined. The majority (20/22) of attaching and effacing positive, eaeA+ E. coli O45 isolates, but none of ten attaching and effacing negative, eaeA- or eaeA+ isolates, expressed a 97-kDa outer membrane protein as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. Amino-terminal amino acid sequencing demonstrated a high homology between this 97-kDa protein of swine E. coli O45 and the EaeA protein (intimin) of human enteropathogenic E. coli and enterohemorrhagic E. coli. In addition, a serological relationship between the EaeA proteins of swine O45, rabbit (RDEC-1) and human (E2348/69) attaching and effacing E. coli strains was observed. Our results indicate an association between expression of the EaeA protein and attaching and effacing activity among O45 E. coli isolates. The data also suggest an antigenic relatedness of the EaeA proteins of swine, rabbit, and human attaching and effacing E. coli.

Adhesins, Bacterial↗
PubMed1995

A novel isoenzyme of aldehyde dehydrogenase specifically involved in the biosynthesis of 9-cis and all-trans retinoic acid.

The pleiotropic effects of retinoids are mediated by two families of nuclear receptors: RAR (retinoic acid receptors) and RXR (retinoid X receptors). 9-cis-Retinoic acid is a specific ligand for RXR receptors, whereas either 9-cis- or all-trans-retinoic acid activates the RAR receptor family. The existence of RXRs suggests a new role for isomerization in the biology of retinoic acid. We report here the identification of an aldehyde dehydrogenase in the rat kidney that catalysed the oxidation of 9-cis- and all-trans-retinal to corresponding retinoic acids with high efficiency, 9-cis-retinal being 2-fold more active than all-trans-retinal. Based on several criteria, such as amino acid sequence, pH optimum, and inhibition by chloral hydrate, this enzyme was found to be a novel isoenzyme of aldehyde dehydrogenase. 9-cis-Retinol, the precursor for the biosynthesis of 9-cis-retinal was identified in the rat kidney. The occurrence of endogenous 9-cis-retinol and the existence of specific dehydrogenase which participates in the catalysis of 9-cis-retinal suggest that all-trans-retinoi(d) isomerization to 9-cis-retinoi(d) occurs at the retinol level, analogous to all-trans-retinol isomerization to 11-cis-retinol in the visual cycle.

Aldehyde Dehydrogenase↗
PubMed1995

Comparison of jet and ultrasonic nebulizers for alveolar targeting of methylprednisolone.

The secondary systemic effects of oral corticosteroid therapy in chronic lung disease indicate the possible benefits of local therapy. The aim of this study was to show if alveolar targeting of a corticosteroid, methylprednisolone (MP), is possible, and to determine which type of nebulizer allows the most selective deposition into the alveoli. A jet nebulizer (Respirgard II) with 2 ml volume fill (R2), and an ultrasonic nebulizer (Ultraneb 99) with 4 ml volume fill (U4), were compared using a 40-mg dose of MP labelled 99Tcm human serum albumin. Particle size and MP-to-albumin binding were measured in the aerosol cloud. Each nebulizer was used in random order in five healthy volunteers. A dynamic posterior scan of 68 images of 15 s each was performed with a Gammatome II gamma camera during inhalation. Peripheral and central regions of interest were automatically defined with reproducible methods, and the peripheral-to-central ratio was used as a penetration index. Stomach and oropharynx activities were estimated on static anterior and static left lateral views, respectively, at the end of the examination. The mass median aerodynamic diameter (MMAD) was lower for R2 when unlabelled MP was used. The MMAD of MP+HSA was compatible with alveolar targeting. In the aerosol cloud, MP-albumin binding was 75% for R2 and 79% for U4. Peripheral and central activities at equilibrium (13-16 min) were higher with U4, but the penetration index was significantly higher with R2. Moreover, the stomach and oropharynx activities were significantly lower with R2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
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

[Quality of psychomotor recovery after colonoscopy under general anesthesia using propofol. Value of tests of awakening].

Achieving colonoscopy under general anaesthesia entails the problem of ambulatory-care anaesthesia, in particular because perception of patient's recovery determines to some extent the length of monitoring following colonoscopy. The aims of the study was to assess the quality of patient's recovery after a colonoscopy under general anaesthesia while using propofol, by means of psychomotor-tests. METHODS--Colonoscopy was performed in 40 patients according to the following anaesthetic protocol: induction: propofol 2 mg/kg, continuous support: propofol 10 mg/kg/h i.v. with a 50 mg bolus in case of insufficient sedation; series of 3 psychomotor-tests were performed the day before and 1 hour, 3 hours and 6 hours after colonoscopy. The 3 psychomotor-tests studied: coordination (Newman test), time-space orientation and short-term memory. RESULTS--Forty patients, 25 females and 15 males, underwent colonoscopy with general anaesthesia for an average time-period of 22 +/- 11 min. The mean dose of propofol used was 286 +/- 102 mg. Awakening was complete in all patients, according to physical criteria such as consciousness and cardiovascular status, 20 min after receiving colonoscopy. The average psychomotor-tests results over time were (as percentages of original values) (*P < 10(-3); **P < 0.05): [table: see text] At 6 hours, 35 patients (87.5%) had recovered to their original performance and at 3 hours, 30 patients (75%) retained 90% their former state as measured with 3 psychomotor-tests. Neither by age or sex nor by propofol doses used or length or anaesthesia, the study population differed significantly. CONCLUSION--Three hours after colonoscopy under general anaesthesia using propofol, 30 patients (75%) had recovered at least 90% to their initial performances. Newman test was the most disturbed but there was no predictive factor for the quality of recovery. Psychomotor-tests may be useful before authorizing early discharge after colonoscopy under general anaesthesia but other recommendations about conditions of discharge after sedation must be also implemented.

Anesthesia Recovery Period↗
PubMed1994

Phosphorylation and identification of a major tyrosine phosphorylation site in protein tyrosine phosphatase 1C.

Protein tyrosine phosphatase 1C (PTP1C) was the first member of the protein tyrosine phosphatase family demonstrated to contain the src homology 2 (SH2) domain. This enzyme is believed to play a role in regulating downstream signaling in hematopoietic cells since it was predominantly expressed in these cells. However, recent studies have revealed that the protein is expressed in other tissues as well. This report describes both the phosphorylation of PTP1C in non-hematopoietic cells treated with growth factors (in vivo) and incubation of purified PTP1C with a variety of protein kinases (in vitro). PTP1C was transiently phosphorylated in A431 and 293 cells and also when the purified enzyme was incubated with receptor protein tyrosine kinases. In vitro, the tyrosine-phosphorylated PTP1C underwent rapid auto-dephosphorylation, an effect which could be blocked by the addition of sodium vanadate. On the other hand, cells containing a PTP1C in which the catalytic site had been inactivated through mutagenesis, stably phosphorylated the phosphatase. These results suggested that PTP1C was responsible for its own auto-dephosphorylation. The sites of tyrosine phosphorylation were characterized from purified enzyme following treatment with insulin receptor kinase and from PTP1C expressed in 293 cells which had been stimulated with platelet-derived growth factor. Through the techniques of peptide mapping and microsequencing, Tyr538 was determined to be the major phosphorylation site. This result was confirmed in vivo through site-specific mutagenesis of PTP1C expressed in 293 cells; changing Tyr538 to Phe538 completely abolished tyrosine phosphorylation of the molecule. In addition, Tyr538 lies within the sequence ESEYGNI which can be correlated with the consensus sequence pYXNX associated with GRB2 binding. These results suggest that PTP1C plays a prominent role in growth factor receptor-mediated signal transduction within both hematopoietic cells and tissues of non-lymphoid origin.

Amino Acid Sequence↗
PubMed1994

Transcatheter oily chemoembolization for hepatocellular carcinoma. A 4-year study of 127 French patients.

BACKGROUND: In Western countries, only a small proportion of patients with hepatocellular carcinoma (HCC) can be treated with surgical resection. For other patients, locoregional management by transcatheter oily chemoembolization seems to be useful and warrants evaluation. METHODS: One hundred and twenty-seven French patients with an inoperable HCC were treated by transcatheter oily chemoembolization. The efficiency of the treatment was assessed by a comparison of this group with a group of 127 untreated patients. Each patient of the treated group was matched closely with an untreated patient for all the main clinical, anatomic, and biologic features that characterize the spontaneous evolution of HCC. RESULTS: The overall probabilities of survival in the treated group were 64%, 38%, 27%, and 27% at 1, 2, 3, and 4 years, respectively; those for the untreated group were 18%, 6%, and 5% at 1, 2 and 3 years, respectively (P < 0.0001). The survival was significantly increased in patients with Okuda Stage I and II disease (P < 0.0001), but not in those with Stage III. Karnofsky and Child-Pugh scores remained stable during the follow-up period and dropped only shortly before patients died. CONCLUSION: Transcatheter oily chemoembolization is an efficient treatment for unresectable HCC for the palliation of symptoms as well as for the prolongation of survival with a good quality of life.

Aged↗
PubMed1994

Gas chromatography applied to the lactulose-mannitol intestinal permeability test.

Intestinal permeability can be modified by various illnesses, trauma and sepsis. Alterations of the intestinal wall can facilitate the diffusion of potentially harmful substances such as endotoxins, as well as bacterial translocation. We describe the validation of a capillary gas chromatographic method for the determination of mannitol and lactulose, used as intestinal permeability probes. The method is linear up to 3 g/l for mannitol and 300 mg/l for lactulose; recovery from overload samples is between 92 to 110%. Intra-assay coefficients of variation (C.V.s) were 2.7 and 6.8% for mannitol and lactulose, respectively, and inter-assay C.V.s were 8.9 and 9.3%. Normal values for 25 healthy subjects (mean +/- S.D.) were 14.5 +/- 3.1% and 0.27 +/- 0.15% for mannitol and lactulose, respectively. The GC method presented is rapid and precise.

Adult↗
PubMed1994

Genetic polymorphism of apolipoprotein E in Caucasian alcoholic cirrhotics.

Steatosis is the most common although inconstant hepatic lesion induced by chronic alcohol consumption. Alcoholic cirrhosis is found in only 20 to 30% of chronic alcohol misusers, which points to the influence of both environmental and genetic factors. Apolipoprotein E (apo E) presents an important polymorphism with three common alleles, epsilon 4, epsilon 3 and epsilon 2. Its modulation role on triglyceride-rich lipoproteins and cholesterol-containing lipoproteins is linked with its interaction with cellular specific receptors. This work aims at studying a possible correlation between apo E polymorphism and alcoholic cirrhosis. The three common alleles were identified by enzymatic amplification (PCR) of genomic DNA from blood samples and analysis of restriction profiles. The distribution of alleles and genotypes was performed in 35 Caucasian cirrhotic patients (medium age 57 years) and compared with the usual distribution of apo E phenotypes in European Caucasian populations. The results show lower epsilon 4 and epsilon 2 allele frequencies and higher epsilon 3 allele frequency in Caucasian alcoholic cirrhotics.

Adult↗
PubMed1993

Chromosome analysis of adenomatous polyps of the colon: possible existence of two differently evolving cytogenetic groups.

A chromosomal study of 42 colonic adenomatous polyps was performed using a technique of direct chromosome analysis derived from the prenatal procedure for diagnosing chromosomal alterations from chorionic villi sampling. Abnormal karyotypes were found in 22 cases. Trisomy 7, the most frequently found alteration, was found in 13 cases, followed by trisomy 13 (nine cases). Monosomy 18 was observed in two cases; in one of these, that of a polyp which had degenerated into an intra-mucosal adenocarcinoma, it was associated with 17p monosomy. Interestingly, these two types of alterations (trisomy 7 versus 18 and 17p monosomy) were not found together in the same lesion. This suggests that there could be two distinct chromosomal behaviors which might be related to the two cytogenetic groups described for colorectal adenocarcinoma. However, the respective frequencies of such cytogenetic groups varied inversely between adenomas and adenocarcinomas, thus suggesting that they evolve differently.

Adult↗
PubMed1993

A species-specific periplasmic flagellar protein of Serpulina (Treponema) hyodysenteriae.

We have previously reported that a 46-kDa protein present in an outer membrane protein preparation seemed to be a species-specific antigen of Serpulina hyodysenteriae (Z. S. Li, N. S. Jensen, M. Bélanger, M.-C. L'Espérance, and M. Jacques, J. Clin. Microbiol. 30:2941-2947, 1992). The objective of this study was to further characterize this antigen. A Western blot (immunoblot) analysis and immunogold labeling with a monospecific antiserum against this protein confirmed that the protein was present in all S. hyodysenteriae reference strains but not in the nonpathogenic organism Serpulina innocens. The immunogold labeling results also indicated that the protein was associated with the periplasmic flagella of S. hyodysenteriae. N-terminal amino acid sequencing confirmed that the protein was in fact a periplasmic flagellar sheath protein. The molecular mass of this protein, first estimated to be 46 kDa by Western blotting, was determined to be 44 kDa when the protein was evaluated more precisely by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the protein was glycosylated, as determined by glycoprotein staining and also by N-glycosidase F treatment. Five other periplasmic flagellar proteins of S. hyodysenteriae, which may have been the core proteins and had molecular masses of 39, 35, 32, 30, and 29 kDa, were antigenically related and cross-reacted with the periplasmic flagellar proteins of S. innocens. Finally, serum from a pig experimentally infected with S. hyodysenteriae recognized the 44-kDa periplasmic flagellar sheath protein. Our results suggest that the 44-kDa periplasmic flagellar sheath protein of S. hyodysenteriae is a species-specific glycoprotein antigen.

Amino Acid Sequence↗
PubMed1993

Detection of HCV-RNA in saliva of patients with chronic hepatitis C.

Previous studies have provided conflicting results on the presence of hepatitis C virus-RNA in saliva. In this study, 23 (62%) of 37 patients tested positive for hepatitis C virus-RNA in saliva, using polymerase chain reaction analysis. A slightly greater proportion had a sporadic rather than a parenteral origin of chronic hepatitis C. These results provide a biological basis for saliva as a possible source of hepatitis C virus (HCV) infection, but do not necessarily imply transmission by this route.

Adult↗