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Biomedical subjects

F Gosselin

Publications and source records attributed to F Gosselin.

13 recordsLinked to original sources

Evaluation of commercial antisera for Shigella serogrouping.

Shigella serogrouping antisera from six companies (Becton Dickinson, Denka, Difco, Murex, Roach, and Sanofi-Pasteur) intended for the slide agglutination test and those of the Wellcolex Colour Shigella latex agglutination test were evaluated to identify quality products for Shigella identification. Forty-six reference Shigella strains (one for each serotype and species), 50 clinical strains (21 S. flexneri, 21 S. sonnei, 4 S. dysenteriae, 4 S. boydii) representing the most prevalent species and serotypes encountered in Quebec, and 9 non-Shigella strains were tested according to the manufacturers' instructions. A 3+ reaction (> or = 75% agglutination) was considered positive for the slide agglutination tests. Sensitivity varied from 47% (Roach) to 94% (Difco). For the 105 strains tested, accuracy ranged from 53% (Roach) to 91% (Wellcolex). Specificity varied from 97 to 100% for group A antisera, from 96 to 100% for group B antisera, from 88 to 100% for group C antisera, and from 95 to 99% for group D antisera. The costs of reagents required to test one strain varied from $3.50 to $13.20 (in Canadian dollars). In conclusion, Roach reagents proved to be unsatisfactory for Shigella serogrouping. Among those from the remaining companies, the Denka, Difco, and Wellcolex reagents met a performance standard of 90% accuracy.

Agglutination Tests

Red blood cell Cu/Zn superoxide dismutase activity in sporadic amyotrophic lateral sclerosis.

To determine the possible role of Cu/Zn superoxide dismutase (SOD1) in the pathophysiology of sporadic amyotrophic lateral sclerosis (SALS), we measured SOD1 activity in red blood cell lysates in patients with SALS. SOD1 activity in red blood cell lysates was independent of age and sex in control patients, and no significant difference was found between the levels of SOD1 activity in controls (1174.8 +/- 213, n = 29) and SALS patients (1203.4 +/- 214, n = 27). These results suggest that point mutations in the SOD1 gene are apparently unrelated to SALS.

Adult

[Fetomaternal alloimmunization: role of cordocentesis].

Twenty one pregnancies complicated by alloimmunization were managed by the use of intravascular method on an outpatient basis. One group was made of 9 women having had at least one pregnancy with a severely affected fetus. The other group was composed of 12 women without a previously affected infant; in 5 cases a situation at risk, either a transfusion (4 cases) or a severe obstetrical hemorrhage (1 case), was evidenced. Knowledge of fetal blood type (2 cases) and hematocrit determination obtained by fetal blood sampling allowed treatment individualized to the specific needs of each patient. In total 59 cordocenteses were performed, including 19 intrauterine transfusions.

Blood Transfusion, Intrauterine

Cytokeratins as molecular markers in the evaluation of the precise differentiation stage of human gingival epithelium reconstituted in vitro.

Cytokeratins are considered to be molecular markers for different types of epithelial differentiation. They were used to investigate the precise differentiation stage of gingival epithelium, reconstituted in vitro, following two different culture procedures. Human trypsin-dissociated gingival keratinocytes were seeded either on a feeder layer of irradiated mouse 3T3 fibroblasts or on a connective tissue equivalent (lattice) made up of human fibroblasts in a collagen gel. The cytokeratins were extracted and analysed by two-dimensional gel electrophoresis. Although both methods showed on histological sections that cultured gingival keratinocytes formed a multilayered non-keratinizing epithelium, the cytokeratins patterns showed great differences. The gingival epithelium-like structure reconstituted on 3T3 feeder layer expressed some cytokeratins characteristic of the in situ gingival epithelium (K 5, 6, 14, 16, 17) and some which do not exist in the normal tissue (K 8, 18, 19, traces of K 13 and K 15) and are specific for embryonic, simple and tumour epithelia. However, the gingival epithelium reconstituted on connective tissue equivalent expressed all the cytokeratins present in the normal tissue (K 5, 6, 14, 16, 17), except those specific for terminal differentiation (K 1, 2, and 10/11). These findings suggest that the culture of gingival keratinocytes on connective tissue equivalents allows them to reproduce physiological stages of differentiation.

Biomarkers

[Chorionic villi sampling: experience of the initial 500 samples].

We report our experience in first trimester antenatal diagnosis since 1984. Transcervical chorionic villus sampling (CVS) was performed in 498 pregnancies. The rate of abnormal pregnancies was 6%, the rate of chromosomal abnormalities (trisomy) in the indication group "maternal age" was 2%. The fetal loss rate (until 28 weeks) was 3.4% (17 cases), the procedure related loss plus the background loss was 2.4% (12 cases). For 92.8% of the patients a diagnosis was available after 1 CVS procedure. Ultimately an antenatal diagnosis was given to 99% of the women through a second CVS procedure or an amniocentesis or a cordocentesis. No maternal complication was observed.

Chorionic Villi Sampling

[Cordocentesis: experience in 391 initial samples].

The first diagnostic cordocentesis was performed in our unit in october 1985. Our 4-year experience is reported: 391 cordocentesis were performed in 360 patients during gestational weeks 14 to 42. The first attempt was successful in 90% of the procedures, 4 samplings failed, there were 4 fetal deaths within one week after diagnostic cordocentesis, one of them appears to be directly linked to the punction. A transient fetal bradycardia was observed in 9.9% of the cases, bleeding occurred in 19% of the cases. The indications for cordocentesis were: risk of fetal infection, karyotyping, hemopathy, search for paternity, assessment of fetal acid-base status, biochemical dosage. Our data confirm that cordocentesis is a safe and reliable diagnostic procedure providing guidelines for management of the pregnancy.

Chromosome Aberrations

[Reconstitution in vitro of human gingiva].

A model of human gingiva to be used in pharmacological, basic and clinical research was performed in vitro. This model was obtained through a method of low density seeding epithelialization, from a seeding made up of dissociated human gingiva epithelial cells, of a connective tissue equivalent composed of human fibroblasts included in a collagen gel. The histological and ultrastructural data show a multilayered epithelium and the biochemical analysis (two dimensional gel electrophoresis known as NEPHGE) of the cytokeratins used as molecular markers for epithelial differentiation shows the precise differentiation state of the epithelium thus reconstituted. Even though this model has less of a differentiation than that of an in vivo gingival epithelium, it does actually reproduce exactly the structures of the human gingiva namely a multilayered epithelium lying on a connective tissue. It also offers the advantage of cellular elements which are compatible with gingival graftings.

Electrophoresis, Gel, Two-Dimensional

Cytokeratin patterns of human oral epithelia: differences in cytokeratin synthesis in gingival epithelium and the adjacent alveolar mucosa.

Human oral mucosa includes various epithelia that are commonly classified as lining, masticatory, and specialized epithelia. Although adjacent tissues, the gingiva and alveolar mucosa represent two different types of epithelia: the gingiva is cornified and exhibits high rate ridges, whereas the mucosa does not normally cornify and exhibits a relatively smooth-contoured borderline between the epithelium and the underlying connective tissue. We examined the cytokeratin patterns of both epithelia using one- and two-dimensional gel electrophoresis. The gingiva expresses a great complexity of cytokeratins, including significant amounts of components nos. 1, 2, 5, 6, 10, 11, 13, 14, 16, and 17, as well as traces of cytokeratins nos. 4 and 15, i.e., a pattern similar to those of vaginal mucosa and epidermis containing proliferative keratinocytes. In contrast, the alveolar mucosa contains only two major cytokeratins, i.e., nos. 4 and 13, together with two minor amounts of cytokeratins nos. 5, 6, 14, and 17, thus resembling the patterns of certain other stratified, noncornified epithelia, such as the esophagus. Immunofluorescence microscopy using monoclonal antibodies to cytokeratins nos. 4 and 13 revealed the presence of these proteins in the suprabasal layers of alveolar mucosa, whereas in the gingiva, only certain small, suprabasal clusters of cells appeared to contain these cytokeratins. The cytoskeletal differences between gingival and alveolar mucosa are discussed in relation to the differences in their morphology and function, and with respect to pathological processes characteristic of these epithelia.

Cytoskeletal Proteins

[Coexistence of Legionnaires' disease and Q fever in a single patient].

A case of Legionnaires' disease associated with Q fever is presented; this is probably the first reported case of concomitant infections with Legionella pneumophila and Coxiella burnetii. The pulmonary features of the illness were not typical of either disease. The difficulties of making a diagnosis in such cases are discussed.

Adult

Severe protracted diarrhea due to multiresistant adherent Escherichia coli.

We studied 15 cases of severe protracted diarrhea due to a strain of Escherichia coli serotype 0111: K58 :H2. The clinical features of these patients were compared with those of 18 patients infected with other enteropathogenic serotypes of E coli. More patients infected with 0111: K58 :H2 strains had been treated with ampicillin (six of 15 v one of 18), and more were dehydrated (nine of 15 v two of 18) and in a toxic condition (nine of 15 v three of 18). The number of stools per day (14.1 v 6.8), the total duration of the diarrhea (24.7 v 7.0 days), and the frequency of relapses (six of 15 v none of 18) were also greater in these patients. A large number had a serum sodium level below 135 mEq/L (ten of 15 v none of 18) and a serum protein level below 11 mEq/L (six of 15 v none of 18). At least two infants infected with E coli 0111: K58 :H2 manifested a urinary tract infection. All 15 strains of E coli 0111: K58 :H2 studied adhered to HeLa cell lines, whereas none of the strains isolated from the second group were adherent. None of the 0111: K58 :H2 strains produced enterotoxins, and they were negative in the Ser eny test. All adherent strains were resistant to many antibiotics.

Adhesiveness