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J Ouellet

Publications and source records attributed to J Ouellet.

12 recordsLinked to original sources
PubMed2006

Role of androgens and glucocorticoids in the regulation of diazepam-binding inhibitor mRNA levels in male mouse hypothalamus.

In peripheral organs, gonadal and adrenal steroids regulate diazepam-binding inhibitor (DBI) mRNA expression. In order to further investigate the involvement of peripheral steroid hormones in the modulation of brain DBI mRNA expression, we studied by semiquantitative in situ hybridization the effect of adrenalectomy (ADX) and castration (CX) and short-term replacement therapy on DBI mRNA levels in the male mouse hypothalamus. Cells expressing DBI mRNA were mostly observed in the arcuate nucleus, the median eminence and the ependyma bordering the third ventricle. In the median eminence and the ependyma bordering the third ventricule, the DBI gene expression was decreased in ADX rats and a single injection of corticosterone to ADX rats induced a significant increase in DBI gene expression at 3 and 12 h time intervals without completely restoring the basal DBI mRNA expression observed in intact mice. In the arcuate nucleus, ADX and corticosterone administration did not modify DBI mRNA expression. CX down-regulated DBI gene expression in the ependyma bordering the third ventricle. The administration of dihydrotestosterone (3-24 h) completely reversed the inhibitory effect of CX. In the median eminence and arcuate nucleus, neither CX or dihydrotestosterone administration modified DBI mRNA levels. These results suggest that the effects of glucocorticoids on the hypothalamo-pituitary-adrenocortical axis and androgens on the hypothalamo-pituitary-gonadal axis are mediated by DBI.

Adrenalectomy↗
PubMed2004

Cellular localization of mRNA expression of enzymes involved in the formation and inactivation of hormonal steroids in the mouse prostate.

It is well documented that several tissues, including the prostate, are actively involved in the local formation and inactivation of hormonal steroids. To identify the cell types involved in the formation and inactivation of androgens and estrogens in the ventral lobe prostate, we have localized by in situ hybridization (ISH) a large number of steroidogenic as well as steroid-inactivating enzyme mRNAs in the adult mouse prostate. In parallel studies, we also measured enzyme mRNA levels by quantitative real-time PCR (RT-PCR) in ventral lobe prostates. From the results obtained with quantitative RT-PCR, it appears that, with a few exceptions, the enzyme with low mRNA expression could not be detected by ISH. The following enzymes have been localized by ISH: 17beta-hydroxysteroid dehydrogenase (17beta-HSD) types 1, 2, 3, 4, 7, 8, 9, 10, and 11; 5alpha-reductase type 2; 5beta reductase type 1; P450 7alpha hydroxylase; estrogen sulfotransferase type 1; 11beta-HSD types 1 and 2; and UDP-glucuronosyltransferase 1A6. All of these mRNAs are expressed in the epithelial cells of prostatic acini. Several enzyme mRNAs were also localized in stromal cells. Types 1, 7, and 10 17beta-HSD, estrogen sulfotransferase type 1, and 11beta-HSD types 1 and 2 were found only in epithelial cells. The present results indicate that both epithelial and stromal cells in the mouse prostate play a role in local formation and inactivation of hormonal steroids.

Androgens↗
PubMed2000

Sequencing of peach latent mosaic viroid variants from nine North American peach cultivars shows that this RNA folds into a complex secondary structure.

We sequenced 34 new peach latent mosaic viroid (PLMVd) variants isolated from nine different peach cultivars. This study provides the widest view of PLMVd diversity reported to date and includes the original characterization of North American variants, which cannot be differentiated from European sequences. PLMVd appears as a species in which each isolate is a complex mixture of RNAs. Analysis of base-pair covariations supports the hypothesis that PLMVd folds into a complex branched structure with the potential of including three new pseudoknots. The resulting "globular-like" structure is in contrast to the rod-like one adopted by most other viroids.

Base Sequence↗
PubMed2000

Mapping in solution shows the peach latent mosaic viroid to possess a new pseudoknot in a complex, branched secondary structure.

We have investigated the secondary structure of peach latent mosaic viroid (PLMVd) in solution, and we present here the first description of the structure of a branched viroid in solution. Different PLMVd transcripts of plus polarity were produced by using the circularly permuted RNA method and the exploitation of RNA internal secondary structure to position the 5' and 3' termini and studied by nuclease mapping and binding shift assays using DNA and RNA oligonucleotides. We show that PLMVd folds into a complex, branched secondary structure. In general, this structure is similar to that reported previously, which was based on sequence comparison and computer modelling. The structural microheterogeneity is apparently limited to only some small domains. More importantly, this structure includes a novel pseudoknot that is conserved in all PLMVd isolates and seems to allow folding into a very compact form. This pseudoknot is also found in chrysanthemum chlorotic mottle viroid, suggesting that it is a unique feature of the viroid members of the PLMVd subgroup.

Base Sequence↗
PubMed1998

[Interobserver agreement on diagnoses classified according the International Classification of Primary Care].

OBJECTIVE: To measure interobserver agreement on diagnoses classified and coded by family physicians using manual or computerized input modes. METHOD: Used increasingly in a variety of information management systems, the International Classification of Primary Care is the system best adapted to primary care. Ten physicians independently viewed 44 taped medical visits. Five physicians were randomly assigned to manual coding and five to computer coding. The study of reproducibility explored three aspects: written diagnoses, manually coded diagnoses, and diagnoses coded using a software program. The K statistic was calculated in order to compare interobserver agreement. RESULTS: Descriptive analysis of interobserver agreement in the written diagnoses revealed an agreement rate of 70.5% (+/- 6.3). Among physicians using manual coding, the agreement rate was 70.2% (+/- 7.2). In the group using the software program, the agreement rate was 75.0% (+/- 8.7). The K coefficients were low, but three were significant with critical ratios (z) above 1.96. CONCLUSION: Results suggest that input method has no bearing on interobserver agreement and that agreement is more a function of clinical presentation of health problems than of coding process.

Abstracting and Indexing↗
PubMed1995

[Utilization of computerized classification system of primary care: three years of experience].

OBJECTIVE: To develop and implement a computerized version of the International Classification of Primary Care. To create a data bank and to conduct a descriptive study of our clinic's clientele. DESIGN: Testing a software program and creating a data bank. SETTING: Family Medicine Unit at Enfant-Jésus Hospital, Quebec City. PARTICIPANTS: All Family Medicine Unit doctors and patients seen between July 1, 1990, and June 30, 1993. MAIN OUTCOME MEASURE: Description of our clientele's health problems using the ICPC. RESULTS: During the study, 48,415 diagnostic codes for 33,033 visits were entered into the bank. For close to 50% of these visits, two or more health problems were coded. There was good correlation between the description of our clientele and descriptions in other studies in the literature. CONCLUSION: This article describes the development of a data bank in a family medicine unit using a software program based on the ICPC. Our 3-year experiment demonstrated that the method works well in family physicians' daily practice. A descriptive study of our clientele is presented, as well as a few examples of the many applications of such a data bank.

Databases, Factual↗
PubMed1991

Growth hormone and somatostatin gene expression in adult and aging rats as measured by quantitative in situ hybridization.

We have investigated the variations in growth hormone (GH) and somatostatin (SOM) mRNAs in adult, middle-aged and aging rats of both sexes using quantitative in situ hybridization. cDNA probes complementary to GH mRNA and SOM mRNA were used on fixed pituitary and hypothalamic sections, respectively. A clear sexual dimorphism in GH gene expression was observed in all age groups examined, mRNA levels always being higher in males than in females. In male rats, GH mRNA levels reached a maximum at 7 months of age and then dramatically decreased in middle-aged and aging animals. In female animals, the highest expression of GH was observed at 9 months of age followed by a gradual and constant decline during the aging period. SOM mRNA levels in the periventricular nucleus of the hypothalamus also showed a sexual dimorphism in adult rats, being higher in males than females. A gradual decline in SOM mRNA was observed in middle-aged and aging rats of both sexes. These results suggest that middle age and aging are critical periods for the control of GH and SOM gene expression and that the decrease in GH mRNA levels observed during aging is probably not a consequence of an increase of SOM activity.

Aging↗
PubMed1986

The production of high affinity monoclonal antibodies to human chorionic gonadotropin and their application to immunoradiometric assay.

Production of monoclonal antibodies against hCG has been studied using hCG as the antigen. This study reports the successful isolation of hybrid clones secreting monoclonal antibodies specific for hCG with an affinity constant higher than 10(10) M-1. Of 23 fusions, only 17 fusions have produced positive clones which secrete antibodies giving high levels of binding with 125I-labelled hCG in the supernatant. Finally, 6 different monoclonal antibodies have been isolated; 4 of them, specific for the beta-subunit, with a Ka approximately 1.1-4.0 X 10(11) M-1 and 2 others, specific for the alpha-subunit, presenting an affinity of 2.5 X 10(10) M-1. When the antibodies specific for the beta-subunit are used, specific and highly sensitive radioimmunoassays are obtained after only 3 hrs of incubation. Using iodinated monoclonal antibodies specific for the alpha-subunit and tubes coated with antibodies against the beta-subunit, we have developed sensitive immunoradiometric assays.

Animals↗