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Biomedical subjects

H Gauthier

Publications and source records attributed to H Gauthier.

At least 19 recordsLinked to original sources
PubMed2001

Prognostic value of radionuclide angiography in patients with right ventricular arrhythmias.

BACKGROUND: The prognosis of patients with right ventricular (RV) arrhythmias remains uncertain. This study prospectively evaluated the prognostic value of RV and left ventricular (LV) involvement assessed by radionuclide angiography (RNA) as predictors for sudden death. METHODS AND RESULTS: Patients (n=188) with severe arrhythmias originating from the RV were followed up for a mean of 45+/-34 months. Data on clinical presentation, resting and stress ECG, signal-averaged ECG, 24-hour Holter monitoring, and programmed stimulation were collected along with RNA. Patients were classified as group I (n=82) with normal RNA or group II (n=106) with an abnormal RV suggestive of arrhythmogenic RV cardiomyopathy, classified as diffuse or localized disease, with or without associated LV abnormalities. During follow-up, 14 patients died suddenly, all in group II. None of the clinical and electrical data were predictive of death. An abnormal RNA study was a highly predictive factor for death (P<0.005), as well as the presence of LV abnormalities (P<0.01). CONCLUSIONS: The present study confirms that arrhythmogenic RV cardiomyopathy is a severe disease with a high risk for cardiac death. Evidence of RV abnormalities in patients presenting with RV arrhythmias is highly predictive for sudden death, as is its association with LV involvement.

Adolescent↗
PubMed2001

Socio-economic disparities in preterm birth: causal pathways and mechanisms.

Preterm birth is the leading cause of infant mortality in industrialised societies. Its incidence is greatly increased among the socially disadvantaged, but the reasons for this excess are unclear and have been relatively unexplored. We hypothesise two distinct sets of causal pathways and mechanisms that may explain social disparities in preterm birth. The first set involves chronic and acute psychosocial stressors, psychological distress caused by those stressors, increased secretion of placental corticotropin releasing hormone (CRH), changes in sexual behaviours or enhanced susceptibility to bacterial vaginosis and chorioamnionitis, cigarette smoking or cocaine use, and decidual vasculopathy. The second hypothesised pathway is a gene-environment interaction based on a highly prevalent mutation in the gene for methylenetetrahydrofolate reductase (MTHFR), combined with low folate intake from the diet and from prenatal vitamin supplements, consequent hyperhomocysteinemia, and decidual vasculopathy. We propose to test these hypothesised pathways and mechanisms in a nested case-control study within a prospectively recruited and followed cohort of pregnant women with singleton pregnancies who deliver at one of four Montreal hospitals that serve an ethnically and socio-economically diverse population. Following recruitment during the late first or early second trimester, participating women are seen at 24-26 weeks, when a research nurse obtains a detailed medical and obstetric history; administers several scales to assess chronic and acute stressors and psychological function; obtains blood samples for CRH, red blood cell and plasma folate, homocysteine, and DNA for the MTHFR mutation; and performs a digital and speculum examination to measure cervical length and vaginal pH and to obtain swabs for bacterial vaginosis and fetal fibronectin. After delivery, each case (delivery at < 37 completed weeks following spontaneous onset of labour or prelabour rupture of membranes) and two controls are selected for placental pathological examination, hair analysis of cotinine, cocaine, and benzoylecgonine, and analysis of stored blood and vaginal specimens. Statistical analysis will be based on multiple logistic regression and structural equation modelling, with sequential construction of models of potential aetiological determinants and covariates to test the hypothesised causal pathways and mechanisms. The research we propose should improve understanding of the factors and processes that mediate social disparities in preterm birth. This improved understanding should help not only in developing strategies to reduce the disparities but also in suggesting preventive interventions applicable across the entire socio-economic spectrum.

Adult↗
PubMed2000

Systematic lung scans reveal a high frequency of silent pulmonary embolism in patients with proximal deep venous thrombosis.

BACKGROUND: A high frequency of asymptomatic pulmonary embolism (PE) has been reported in patients with deep venous thrombosis (DVT) in studies of a limited number of patients using varying criteria for lung scan assessment. OBJECTIVES: To estimate the frequency of PE using systematic lung scans in a large group of outpatients with DVT and to compare the results using varying lung scan assessment criteria. METHODS: An international multicenter study comparing 2 different regimens of low-molecular-weight heparin nadroparin in DVT: perfusion lung scans were performed in 622 outpatients with no clinical indication of PE and with proximal DVT confirmed by venography. Three hundred seventy-nine of these patients underwent ventilation lung scans. High-probability (HP) scans for PE were assessed separately using either ventilation scans or chest radiographs to define mismatched perfusion defects. RESULTS: Perfusion scans showed abnormalities in 82% of the patients; 59% had segmental defects and 30% had normal scans or scans with a very low probability of PE. Depending on the criteria used, 32% to 45% had HP scans for PE; these percentages were higher in young patients. No relationship was found between extent of thrombosis and HP scans. The estimated frequency of silent PE was 39.5% to 49.5%. During a 3-month follow-up period during which the patients received therapy, the rate of PE recurrence was low (1.3%) and did not differ between patients with baseline HP scans and those with normal scans. CONCLUSIONS: Regardless of what interpretative criteria are used for assessing lung scans in PE, the frequency of silent PE is 40% to 50% in patients with DVT. A baseline lung scan may easily detect PE in these patients but is not useful for predicting early thromboembolic recurrences that may occur during therapy.

Adolescent↗
PubMed1995

[Demographic variables and social dependency: annual and intergenerational comparisons].

"Drawing on a profile of age-specific expenditures for selected [Canadian] Government programmes (services and transfers), we examine the effect of demographic changes and labour force participation on social expenditures in the upcoming decades. In terms of cross-sectional analysis, increased activity rates and particularly a postponed retirement age would exercise a major impact.... Using a different approach, it is possible to distinguish for each generation the social benefits received and corresponding contributions. Whereas the amount of benefits received by a specific cohort essentially depends on its size, contributions vary according to annual social expenditures. The demographic structures are such that the generations born before 1991 will profit from an excess in benefits...while for the following generations the situation will be reversed.... For all scenarios with negative population growth, future generations may expect to incur a deficit in terms of social expenses." (SUMMARY IN ENG AND SPA)

Age Factors↗
PubMed1991

[Consequences of population aging on social expenditures].

The impact of demographic aging on social expenditures is examined, with particular reference to Canada. "The merits of four of the mechanisms or means that are proposed to alleviate the additional cost of aging are reviewed: economic growth, increase in the labour force participation rate, economies of scale and [restructuring] of social expenditures. We bring up many uncertainties regarding the mechanisms or means proposed. Therefore we should not take for granted that the effect of aging will be easily absorbed." (SUMMARY IN ENG)

Americas↗
PubMed1990

[Changes in the age structure of the labor force by occupation in Quebec, 1981-1986].

The author examines trends in the age structure and size of the labor force in Quebec, Canada, for the period 1981-1986. "Using simulations, the author shows that the occupational structure of workers as a whole is less influenced by the decrease in the number of young workers...than by occupational changes observed among young workers." (SUMMARY IN ENG AND SPA)

Age Distribution↗
PubMed1986

[Three projections of population decline for Quebec: characteristics and implications for the working population].

"After a brief review of various projections of population decline for Quebec, the author analyses some previous examples of depopulation, and emphasizes that public opinion will have to change much if immigration is to be used as a tool for avoiding population decline. He then investigates four implications of the projected decline: the size of the working population, its age and sex structure, the labor force participation ratio, and the economic dependency ratio." (SUMMARY IN ENG AND SPA)

Age Factors↗
PubMed1976

[Correlation between immunological stage and response to chemotherapy. Results in 64 patients with nonresectable epidermoid bronchial cancers].

Out of 64 patients with non resectable epidermal bronchus carcinoma, 26 patients had before any treatment positive responses of skin tests to recall antigens. In these patients we found a correlation between the reactivity of the skin tests, the presence of seric factor inhibiting the leucocyte migration, the mean count of peripheral lymphocytes and the response to combination chemotherapy protocol. The patients who respond to treatment have a significantly better prognosis than the patients who do not respond. With this correlation it seems to be possible to distinguish between two populations of patients with non resectable bronchus carcinoma : one population with a good risk who can be significantly improved by the treatment : the other population with a very severe prognosis.

Adrenal Cortex Hormones↗
PubMed1976

Treatment of malignant gliomas and brain metastases in adults with a combination of adriamycin, VM 26, and CCNU. Results of a phase II trail.

Forty-three patients with inoperable or recurring malignant gliomas, and 30 patients with multiple recurring brain metastases were treated with a combination of Adriamycin (45 mg/m2) and 4-dimethyl-epipodophyllotoxin D-thenylidene (VM 26) (60 mg/m2 for 2 days) with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) (60 mg/m2 for 2 days). These cycles of treatment were repeated as soon as the hematologic restoration was complete. The treatment was well tolerated and the clinical condition of 31 of 43 glioblastoma patients improved during the 2 months after the beginning of the treatment. Six of eight patients with breast cancer metastases, one of 13 with bronchial cancer matastases, and three of nine with other types of cancer metastases also benefitted from the treatment. Examination of the results obtained revealed the following characteristics: 1) This combination had a low degree of efficiency in the treatment of metastases to brain, except for breast cancer metastases; 2) there was no complete correlation between the clinical results observed and the cinegammagraphic developments; 3) the results obtained were similar, independent of the initial localization; and a 6-month median survival period was established, with 10 patients now in a state of apparently complete remission, 180 to 506 days after beginning of the treatment.

Adult↗
PubMed1975

Synthesis and pharmacological properties of 4-piperazino-5-methylthiopyrimidines. Selection of new antiemetic agents.

We have synthetized a series of 22 new 4-piperazinopyrimidines bearing a methylthio substituent in the 5 position of the pyrimidine ring. These compounds have been obtained by separation of the isomers formed during nucleophilic attack of the corresponding 2,4,6-trichloropyrimidine by amines. Pharmacological screening has shown that this chemical series displays a very interesting profile, which includes antiemetic, tranquilizing, analgesic, antiserotonin, and musculotropic-spasmolytic properties. We have particularly selected for clinical investigations two compounds with powerful antiemetic activity: 2-methylamino-4-(N-methylpiperazino)-5-methylthio-6-chloropyrimidine and 2-isopropylamino-4-(H-methylpiperazino)-5-methylthio-6-chloropyrimidine.

Animals↗