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Biomedical subjects

S Gagnon

Publications and source records attributed to S Gagnon.

14 recordsLinked to original sources
PubMed1992

Physical and genetic mapping of cloned ribosomal DNA from Toxoplasma gondii: primary and secondary structure of the 5S gene.

The ribosomal DNA (rDNA encoding rRNA) of the obligately intracellular protozoan parasite, Toxoplasma gondii, was identified, cloned, physically mapped, its copy number determined, and the 5S gene sequenced. Using total RNA as a probe, a collection of recombinant lambda phages containing copies of rDNA were isolated from a lambda 2001 tachyzoite genomic library. Northern gel hybridization confirmed specific homology of the 7.5-kb rDNA unit, subcloned into pTZ18R, to T. gondii rRNA. The mapped rDNA found in pTOX1 contained small ribosomal subunit (SS; 18S)- and large ribosomal subunit (LS; 26S)-encoding genes localized using intragenic heterologous probes from the conserved sequences of the SS (18S) and LS (28S) Xenopus laevis genes. the physical mapping data, together with partial digestion experiments and Southern gel hybridization, confirmed a 7.5-kb rDNA unit arranged in a simple head-to-tail fashion that is tandemly repeated. We estimated the rDNA repeat copy number in T. gondii to be 110 copies per haploid tachyzoite genome. Parts of the SS gene and the complete 5S gene were sequenced. The 5S gene was found to be within the rDNA locus, a rare occurrence found only in some fungi and protozoa. Secondary-structure analysis revealed an organization remarkably similar to the 5S RNA of eukaryotes.

Animals↗
PubMed1992

Nature and frequency of chromosomal abnormalities in pregnancies with abnormal ultrasound findings: an analysis of 117 cases with review of the literature.

During a 7-year period, 117 fetal karyotypes were available from 131 genetic amniocenteses. These procedures were performed between 14 and 37 weeks' gestation for the following abnormal ultrasound findings: (1) intrauterine growth retardation (IUGR)--61 cases; (2) fetal malformation--71 cases; and (3) amniotic fluid volume (AFV) abnormality--60 cases. Chromosomal abnormalities were identified in 19 cases (16.2 per cent). Aneuploidy was 2.5 times as frequent in the presence of malformations than in their absence. No correlation was demonstrated between specific fetal malformations and specific chromosomal abnormalities. Aneuploidy was also twice as frequent in the presence of symmetrical IUGR than in its absence. No chromosomal abnormalities were found among eight cases of asymmetrical IUGR. Four cases of aneuploidy presented with isolated IUGR, three of these involving the X chromosome. The frequency of aneuploidy was the same with or without abnormalities of AFV (14.3 versus 16.4 per cent). No chromosomal abnormality was found associated with isolated AFV abnormalities.

Adult↗
PubMed1992

Search behavior in various breeds of adult dogs (Canis familiaris): object permanence and olfactory cues.

Human analog tests of object permanence were administered to various breeds of adult dogs (Canis familiaris). Experiment 1 showed that the performance of terriers, sporting, and working dogs did not differ. Dogs succeeded in solving invisible displacement problems, but performance was lower than in visible displacement tests. Familiarity with the task had some influence because invisible displacement tests were more successful if they were preceded by visible displacement tests. In Experiment 2, odor cues from the target object and the hiding screens were available or were masked. Results confirmed that success was lower in invisible than in visible displacement tests and that these problems were solved on the basis of representation of visual information rather than on the basis of olfactory cues or of local rule learning. Dogs are compared with other species that display Stage 6 object permanence.

Animals↗
PubMed1992

Treatment of cervical intraepithelial neoplasia using the loop electrosurgical excision procedure.

In selected patients with cervical intraepithelial neoplasia (CIN), outpatient ablative procedures represent a readily accepted and highly effective treatment modality. The recently introduced loop electrosurgical excision procedure offers a quick and simple alternative to cryotherapy and laser ablation for treating CIN, and has the distinct advantage of allowing both diagnosis and treatment of selected patients at a single visit. This report presents our clinical experience treating 432 patients with CIN using the loop electrosurgical excision procedure on an outpatient basis. Small loop electrodes were used to excise CIN lesions in 275 patients, and large loop electrodes were used in 157. When performed on an outpatient basis under local anesthesia, loop excision was well tolerated by patients with only minimal discomfort. Post-treatment bleeding occurred in less than 2% of the subjects and responded to either recauterization or packing of the cervix. Post-treatment stenosis occurred in less than 1%. The success rate of the loop electrosurgical excision procedure, as defined by absence of cytologic, histologic, or colposcopic lesions 4-48 months after therapy, was 80% for women treated using the small loop electrodes. Ninety percent of all patients treated using the large loop electrodes were free of disease during 6-12 months of follow-up. For women being treated for primary (as opposed to recurrent) disease, the success rate with large loop electrodes was 94%.

Carcinoma in Situ↗
PubMed1990

Corticosteroids as adjunctive therapy for severe Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. A double-blind, placebo-controlled trial.

BACKGROUND: Preliminary reports suggest that patients with the acquired immunodeficiency syndrome (AIDS) and Pneumocystis carinii pneumonia may benefit from the addition of corticosteroid treatment to antibiotic therapy. METHODS: We conducted a double-blind, placebo-controlled trial to assess the efficacy of adjunctive corticosteroids in patients with AIDS and severe P. carinii pneumonia. Patients with marked abnormalities in gas exchange who had been treated with antibiotics for less than 72 hours were randomly assigned to receive either methylprednisolone (40 mg) or placebo every 6 hours for 7 days, in addition to treatment for 21 days with trimethoprim-sulfamethoxazole. The primary outcome measures were survival until hospital discharge and the development of respiratory failure. RESULTS: Twenty-three patients were enrolled in the study; there were no significant differences in base-line clinical or laboratory measures between the two treatment groups. Of 12 patients treated with corticosteroids, 9 (75 percent) survived until hospital discharge, as compared with only 2 of 11 placebo recipients (18 percent) (P less than 0.008). Respiratory failure developed in nine placebo recipients, as compared with only three patients treated with corticosteroids (P less than 0.008). No patient required the interruption or discontinuation of corticosteroid or antibiotic treatment because of toxicity or a complicating event. Because of the marked difference in survival, it was deemed unethical to continue the trial, and the study was terminated. CONCLUSIONS: Early adjunctive corticosteroid therapy can improve survival and decrease the occurrence of respiratory failure in patients with AIDS and severe P. carinii pneumonia.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Expression of Zn-alpha 2-glycoprotein and PSP-94 in prostatic adenocarcinoma. An immunohistochemical study of 88 cases.

Zn-Alpha 2-Glycoprotein (Zn-Alpha 2-GP) and prostatic secretory protein of 94 amino-acids (PSP-94) were recently isolated from the human prostate. Their expression in benign and malignant well-differentiated and poorly differentiated components of 88 prostates with prostatic adenocarcinomas, and in 25 metastases, was evaluated using polyclonal antibodies developed against these antigens. Zn-Alpha 2-GP was present in benign hyperplastic glands in 91.1% of cases, but in only 40.7% (poorly differentiated component) to 48.5% (well-differentiated component) of prostatic adenocarcinomas, and in 8% of metastases. The expression of PSP-94 was present in 89.3% of benign hyperplastic glands, but in only 50% (well-differentiated adenocarcinoma component) to 57.3% (poorly differentiated component) of prostatic adenocarcinomas and 28% of metastases. The expression of these proteins by the tumor was unrelated to the initial stage and the tumor grade. Because of their low frequency in prostatic adenocarcinomas, especially in metastases, Zn-Alpha 2-GP and PSP-94 appear to have a limited diagnostic usefulness. Further studies are needed, however, to explore other clinical applications of these two new prostatic secretory proteins.

Adenocarcinoma↗
PubMed1989

Striatal D1 dopamine receptor density fluctuates during the rat estrous cycle.

Striatal D1 dopamine (DA) antagonist binding sites were investigated in intact female and male rats, ovariectomized (OVX) animals and during the 4-day estrous cycle. The affinity of the striatal D1 receptor as labelled with [3H]SCH 23390 remains unchanged in intact male, female rats during the estrous cycle and OVX animals. By contrast, ovariectomy decreased striatal D1 receptor density by 17% (P less than 0.01) compared to intact female rats while a small but significant higher density was observed in intact male compared to female rats (10% higher, P less than 0.05). The density of striatal D1 DA receptor was higher on the day of diestrus I (DI) and diestrus II (DII) (P less than 0.01 vs OVX) and fluctuates throughout the estrous cycle with a maximum on the day of DII (P less than 0.05 vs proestrus PM). Our results show for the first time that striatal D1 DA receptors fluctuate during the estrous cycle and can be modulated by gonadal steroids.

Animals↗
PubMed1989

Pulmonary function test study and after spinal fusion in young idiopathic scoliosis.

A homogeneous population of 42 women with idiopathic scoliosis (mean age, 20.8 years and mean major thoracic curve of 58.2 degrees) had a complete pulmonary function test (PFT) at rest before, and a minimum of 3 years after, spinal fusion (mean, 7.7 years) to evaluate the effect of scoliosis and its surgical correction on PFT at rest. A multifactorial analysis showed that only the vital capacity (VC) was significantly lowered to 81% of predicted value (P less than 0.05). All of the other parameters of pulmonary volumes, flow, and gas exchanges, where corrected for the loss of lung volume, were within normal limits, showing pure restrictive changes in this population. Double-major curves were more severe, but no significant difference in PFTs were found with single thoracic curves. Curves over 50 degrees had significantly lower VC. The surgical correction of 40% is permanent and the functional improvement in postoperative vital capacity (VC) of 12% is significant (P less than 0.05). Other factors, such as the time between the two evaluations, the age of the patient, pelvic obliquity, trunk imbalance, and degree of kyphosis did not have any correlation with the observed changed on any of the PFT results. Therefore, early correction by spinal fusion in idiopathic scoliosis brings on some improvement of the vital capacity at rest and may prevent deterioration with progression of the curve.

Adolescent↗
PubMed1989

Psychology of computers: XIV. Cognitive rehabilitation through computer games.

The purpose of this study was to test the hypothesis that computer games may be an efficient therapeutic tool in a cognitive rehabilitation program. 60 subjects who showed attention difficulties with or without cerebral dysfunctions participated in a 12-hr. training program based on intensive use of a computer game. Analyses show improvement for the experimental group on scanning and tracking variables, notwithstanding the nature of their particular dysfunctions. Recommendations are presented regarding the nature and content of the cognitive tasks in a rehabilitation program.

Adolescent↗
PubMed1989

Frequency of alpha-fetoprotein production by Sertoli-Leydig cell tumors of the ovary: an immunohistochemical study of eight cases.

Eight Sertoli-Leydig cell tumors (SLCT) of the ovary were studied by immunostaining for alpha-fetoprotein (AFP). Immunostaining was positive only in cells resembling Leydig cells in three cases and in both Sertoli and Leydig cells in one instance. In one SLCT with positive immunostaining, serum AFP was available and was elevated. Serum level was not measured in the seven other cases. Despite the small number of cases, this study suggests that AFP expression in ovarian SLCT is not unusual. The serum AFP level may, however, depend on the size of the tumor, the proportion of Leydig cells present, and their ability to produce and to release AFP into the bloodstream.

Female↗
PubMed1976

[Parapsoriasis].

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Acute Disease↗