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Biomedical subjects

T Niyonsenga

Publications and source records attributed to T Niyonsenga.

18 recordsLinked to original sources

Changes in the components of moral reasoning during students' medical education: a pilot study.

INTRODUCTION: Many authors are concerned by students' moral reasoning not developing normally during medical education. AIM: This study is concerned with how the components of student' moral reasoning are affected by their medical studies. METHODS: Ninety-two medical students were tested on entry into first year and on finishing third year, to determine evolutionary changes in their moral reasoning. Changes in their use of arguments specific to each stage of moral development were measured. RESULTS: Significant changes were observed in the weighted global score (-18.14 +/- 59.17, P = 2.8%). Changes in global score correlated with changes in stages of moral reasoning. The multivariate structure of moral reasoning was reorganised into two principal components, which, respectively, explained almost 82% (first year) and 72% (third year) of the total variability in scores. Moral reasoning stages characterized by law-and-order and social-contract/legalistic orientations proved important for explaining the variability in students' moral reasoning at the start of medical training, while instrumental-relativist and interpersonal-concordance orientations explained variability post third year. CONCLUSIONS: Students restructure their handling of ethical questions by using arguments with more instrumental-relativist and interpersonal-concordance orientations, rather than those of the more desirable law-and-order or social-contract/legalistic type. To assess better the skills required for moral reasoning, a more sophisticated approach is needed than that of a simple measure of improvement/stagnation/deterioration.

Adult↗

Effectiveness of a mass immunization campaign against serogroup C meningococcal disease in Quebec.

CONTEXT: An outbreak of meningococcal disease in Quebec province prompted a mass immunization program. The impact of this campaign on the epidemiology of meningococcal disease has not been studied. OBJECTIVES: To study the impact of a mass immunization campaign using polysaccharide vaccine on the epidemiology of meningococcal disease (MCD) and to assess serogroup C vaccine effectiveness (VE). DESIGN, SETTING, AND SUBJECTS: Analysis of MCD cases reported in Quebec from 1990 to 1998, before and after the mass immunization campaign was conducted during the winter of 1992-1993, when 84% of residents aged 6 months to 20 years (the target population, approximately 1.9 million individuals) were vaccinated. MAIN OUTCOME MEASURES: Incidence of MCD in 1990-1998; incidence of culture-proven serogroup C MCD between April 1, 1993, and March 31, 1998, compared among vaccinated and unvaccinated persons in the target population. RESULTS: The incidence of serogroup C disease decreased after the mass immunization campaign, from 1.4 per 100 000 in 1990-1992 to 0.3 per 100 000 in 1993-1998, and the overall incidence of other serogroups remained stable at 0.7 per 100 000, with a small increase in the proportion of cases caused by serogroup Y (P =.009). Protection from serogroup C MCD was indicated in the first 2 years after vaccine administration (VE, 65%; 95% confidence interval [CI], 20%-84%), but not in the next 3 years (VE, 0%; 95% CI, -5% to 65%). Vaccine effectiveness was strongly related to age at vaccination: 83% (95% CI, 39%-96%) for ages 15 through 20 years, 75% (95% CI, - 17% to 93%) for ages 10 through 14 years, and 41% (95% CI, -106% to 79%) for ages 2 through 9 years. There was no evidence of protection in children younger than 2 years; all 8 MCD cases in this age group occurred in vaccinees. CONCLUSIONS: Serogroup C polysaccharide vaccine is effective for controlling outbreaks in teenaged individuals but should not be used in children younger than 2 years. The mass campaign did not induce significant serogroup switching.

Adolescent↗

Thiols can either enhance or suppress DNA damage induction by catecholestrogens.

The estrogen metabolites catecholestrogens (or hydroxyestrogens) are involved in carcinogenesis and the development of resistance to methotrexate. This induction of drug resistance correlates with the relative efficiency of catecholestrogens in the generation of reactive oxygen species (ROS) and the induction of DNA strand breaks. Although antioxidants can neutralize ROS, the generation of these reactive species by catecholestrogens can be enhanced by electron donors like NADH. Therefore, this study was undertaken to determine the ability of different thiol agents (GSH, NAC, DTT, DHLA) to either inhibit or enhance the level of DNA damage induced by the H(2)O(2) generating system 4-hydroxyestradiol/Cu(II). Our results show that GSH, DTT, and DHLA inhibited the induction of the 4-hydroxyestradiol/Cu(II)-mediated DNA damage, with GSH showing the best potential. In contrast, the GSH precursor NAC at low concentrations was able to enhance the level of oxidative damage, as observed with NADH. NAC can reduce Cu(II) to Cu(I) producing the radical NAC&z.rad;, which can generate the superoxide anion. However, the importance of this pathway appears to be relatively minor since the addition of NAC to the 4-hydroxyestradiol/Cu(II) system generates about 15 times more DNA strand breaks than NAC and Cu(II) alone. We suggest that NAC can perpetuate the redox cycle between the quinone and the semiquinone forms of the catecholestrogens, thereby enhancing the production of ROS. In conclusion, this study demonstrates the crucial importance of the choice of antioxidant as potential therapy against the negative biological effects of estrogens.

Acetylcysteine↗

Family history and the risk of coronary heart disease: comparing predictive models.

Family history is commonly used when evaluating coronary heart disease (CHD) risk yet it is usually treated as a simple binary variable according to the occurrence or non-occurrence of disease. This definition however fails to consider the potential components of a family history which may in fact exert different degrees of influence on the overall risk profile. The purpose of this paper is to compare different predictive models for CHD which incorporate family history as either a binary variable or different types of family risk indices in terms of their predictive ability. Models for estimating CHD risk were constructed based on usual risk factors and different family history variables. This construction was accomplished using logistic regression and RECursive Partition and AMalgamation (RECPAM) trees. Our analyses demonstrate the importance of using more sophisticated definitions of family history variables compared to a simple binary approach since this leads to a significant improvement in the predictive ability of CHD risk models.

Adult↗

Reliability of Chalmers' scale to assess quality in meta-analyses on pharmacological treatments for osteoporosis.

PURPOSE: This study estimates the inter-rater and test-retest reliability of Chalmers' quality score scale in the context of bone mass loss and fracture rate in postmenopausal women. METHODS: An exhaustive literature search was performed on Medline to locate clinical trials studying the effect of medication use on bone mass loss and fracture rate in postmenopausal women. Twenty articles were randomly selected and four raters independently assessed the quality of each article with Chalmers' scale. Among the 20 articles, 10 were blinded on authors' names, journal, year of publication and source of funding. Raters were also asked to assess all 20 articles one more time, two months after the first evaluation. Intraclass (ICC) and test-retest correlation coefficients were calculated. RESULTS: The overall inter-rater ICC was 0.66 [0.55, 0.79](95%). The overall test-retest reliability of Chalmers' scale was 0.81 [0.67, 0. 98](95%). When ratings were stratified according to articles' blinding status, blinded assessments generated a smaller inter-rater ICC than non-blinded assessments: 0.30 [0.17, 0.53](95%) vs. 0.80 [0. 71, 0.90](95%). In addition, analyzing sub-scales separately generated different estimates of reliability. CONCLUSIONS: This study shows that the reliability of the quality scale developed by Chalmers substantially varies between sub-scales, and is highly dependent on articles' blinding status. The possibility of bias in rating non-blinded articles can not be ruled out. The reliability of the scale can also be dependent on the outcome studied.

Adult↗

Impact of age and body size on inter-individual variation in measures of lipid metabolism: influence of gender and apolipoprotein E genotype.

This study was undertaken in 1695 adult subjects (870 women and 825 men) in order to further document the complexity of the influence of the apolipoprotein (apo) E genotypes on the mean levels and intragenotypic variability of seven measures of lipid metabolism. In addition, the statistical relationships between variability in these traits and variation in age, body mass index (BMI) and waist-to-hip ratio (WHR) were assessed. The contribution of variation in age and body size to inter-individual variation was found to be dependent on context, defined by gender and apo E genotype. Our findings are consistent with the reality that it is neither genes nor environments, but their interactions that are responsible for the variation in risk of cardiovascular disease.

Adolescent↗

Dyslipidemias and the primary prevention of cardiovascular disease: analysis of the FAMUS primary care register.

BACKGROUND: Primary prevention of cardiovascular disease with a pharmacological approach to dyslipidemias is controversial. Little is known about the clinical management by general practitioners in this area. OBJECTIVES: To evaluate the patterns of treatment of patients in primary prevention who were entered in the FAmily Medicine, Université de Sherbrooke (FAMUS) register and to calculate the probability of their receiving a hypolipidemic agent according to the presence of various risk profiles. PATIENTS AND METHODS: Descriptive study based on the FAMUS prospective primary care register. Data from patients in primary prevention (those who had not sustained a cardiovascular event) were extracted and analyzed. MAIN RESULTS: Of the 52,505 patients in the register, 48, 190 were identified as being in primary prevention. Of these, 22,250 (46.2%) had a complete lipid profile on record, and 2300 had received a prescription for a hypolipidemic agent (4.8%). Patients under pharmacological treatment had significantly higher lipid values. The adjusted relative risk of being treated with a hypolipidemic agent was 1.3 for smokers, 1.3 for diabetic patients, 2.0 for those with a positive family history of premature cardiovascular disease, 2.2 for hypertensives and 3.3 for men over 45 years of age or women over 55 years, compared with patients who were not taking lipid-lowering medications. The number of risk factors was even more strongly associated with the probability of being treated. CONCLUSION: Overall, few patients in primary prevention in the register were treated with a pharmacological agent. The presence of associated risk factors in this study was an important predictor for treatment, suggesting that patients in primary prevention are being evaluated globally as a function of all of their risk factors, not just their lipid and lipoprotein levels. Further attention, nonetheless, needs to be directed to the segment of the population with multiple risk factors whose lipoprotein profile is unknown or who are not being treated to guideline target levels.

Adult↗

A method for the follow-up of clusters of adverse reproductive outcomes.

Clusters of adverse reproductive outcomes are reported with increasing frequency to public health authorities. Most are random events and only a very small proportion is likely due to identifiable environmental agents. Often, a preliminary study confirms the existence of a spatial and temporal excess but no biologically plausible cause is found. These cases require a follow-up of incidence to identify any continuing excess. A conceptually simple 'fixed window' technique of follow up is proposed. The power of the test is mainly influenced by the magnitude of the increase in rate, the number of adverse outcomes selected for observation and the acceptable false alarm rate. This technique has several advantages compared with other currently used methods. From a public health point of view, two important factors are to be considered in setting the parameters of the test: the delay in providing an answer for the community and the availability of resources for conducting environmental investigations.

Bias↗

Thyroarytenoid muscle electrical activity during spontaneous apneas in preterm lambs.

Laryngeal dynamics plays a major role during perinatal life, a period of respiratory control immaturity. Continuous electromyographic (EMG) activity of a laryngeal adductor muscle (thyroarytenoid [TA] muscle), was recently observed throughout provoked central apneas, either isolated or during induced periodic breathing, in full-term lambs. The aim of the present study was to test if continuous TA EMG activity was also present during spontaneous apneas in nonsedated preterm lambs. We studied 7 premature lambs (term 131 +/- 1 d of postconceptional age). Premature birth was induced after acceleration of fetal lung maturation. Electrodes for diaphragm, inferior pharyngeal constrictor (IPC), and TA electromyograms, electrocardiogram, electroencephalogram, eye movement, and airflow recordings were implanted. Radiotelemetry recordings were repeated from 135 to 149 +/- 8 d of postconceptional age. A total of 2,088 apneas (2,020 central and 68 mixed) >/= 3 s were recorded in the lambs, including 57 epochs of periodic breathing. Continuous TA EMG activity was present throughout 88.4% of all apneas and 98.4% of apneas during periodic breathing, regardless of the sleep stage. These results suggest that active glottic closure is frequent during spontaneous central apneas in this model of prematurity. This unique model will allow us to study controlling mechanisms and consequences of glottic closure during neonatal apneas.

Animals↗

Antiplatelet and lipid-lowering therapies for the secondary prevention of cardiovascular disease: are we doing enough?

OBJECTIVE: To evaluate whether current recommendations with respect to the treatment of dyslipidemias and the use of antiplatelet agents are being applied in the secondary prevention of cardiovascular disease in primary care settings. DESIGN: Descriptive study based on data from the FAMUS (FAmily Medicine, Université de Sherbrooke) primary care register. SETTING AND PARTICIPANTS: Two-hundred and thirty-three physicians participating in the FAMUS project contributed information from nonpregnant patients over 20 years of age consulting for a periodic health examination between 1992 and 1996. INTERVENTIONS: Data from patients in secondary prevention (those with or having had angina, a previous myocardial infarction, bypass surgery, coronary angioplasty or peripheral vascular disease) were extracted and analyzed. MAIN RESULTS: Of the 52,505 patients in the register, 4315 (8%) were identified as being in secondary prevention. Overall, 53% were noted as receiving an antiplatelet agent while 4% were taking warfarin therapy. Only 64% (2780) had a complete lipid profile on record while 38% were being treated with a hypolipidemic agent. In the treated group, only 30% had a low density lipoprotein cholesterol level below 3.0 mmol/L compared with 22% in the untreated group. CONCLUSIONS: A large number of patients identified as being in secondary prevention were not screened for dyslipidemias, and, of those who were, the majority were undertreated according to current recommendations. Antiplatelet agents were more widely prescribed but potentially underused.

Aged↗

[Treatment patterns of hypertension in 1996. Data from the Quebec Family Practice, University of Sherbrooke registry].

OBJECTIVE: To describe the treatment of hypertension, alone or in combination with associated conditions, by a group of general practitioners in the FAMUS network and to compare these treatment patterns to the recommendations of the Canadian Hypertension Society Consensus. DESIGN: Descriptive study based on data collected by 233 physicians in the FAMUS provincial register on hypertensive patients treated in 1996. PARTICIPANTS: Developed between 1992 and 1996, the register contains 52,505 patients, 9,094 of whom have high blood pressure. These patients consulted their general practitioners for a complete examination. The data concern the risk factors for cardiovascular disease and include the list of medications prescribed. MAIN OUTCOME MEASURES: Evaluation of the proportions in which various classes of medications were prescribed, and the most common combinations in relation to the presence or absence of associated conditions. RESULTS: Of the 4,049 hypertensive patients seen in 1996, 50.2% were treated with one medication; 32.9% were treated with more than one medication; and 16.9% received no antihypertensive medication. The most frequently prescribed medications were calcium channel blockers (26.1%), followed by diuretics (25.3%), angiotensin-converting enzyme inhibitors (24.3%), and beta-blockers (20.0%). Other agents made up the remaining 4.3% of prescriptions. The proportions were similar for patients without complications who received one medication. CONCLUSIONS: Results of this study suggest that the new molecules are widely used and that treatment patterns differ from the recommendations of the Canadian Hypertension Society Consensus, particularly in the absence of associated conditions.

Adrenergic beta-Antagonists↗

Cardiovascular disease. Physician attitudes toward prevention and treatment.

OBJECTIVE: Survey of physician attitudes toward practising cardiovascular disease prevention. DESIGN: Questionnaire administered via telecommunication from 1992 through 1994. SETTING: The FAMUS (Family Medicine, University of Sherbrooke) project, between 1992 and 1996, used weekly telecommunication to collect data from 200 general practitioners throughout the province of Quebec on cardiovascular disease risk factors and their treatment. PARTICIPANTS: Of 200 physicians contributing to the FAMUS project, 156 completed questionnaires (response rate 78%). MAIN OUTCOME MEASURES: Variations in attitudes to prevention policy and risk factor interventions. RESULTS: Survey results revealed physicians knew important risk factors for cardiovascular disease but differed in attitudes toward efficacy of treatment. Intervention to control cholesterol was thought to be very effective by 21.2% (95% confidence interval [CI] 21.2 +/- 6.4) and without effect by 10.3% (95% CI 10.3 +/- 4.8). Intervention to improve dietary habits was considered ineffective by 48.1% (95% CI 48.1 +/- 7.8). Confidence in managing risk factors varied; most respondents described themselves as only moderately skilled. A few practitioners (30.1%; 95% CI 30.1 +/- 7.2) acknowledged practice guidelines as an important source of information on which to base preventive interventions. Only 14.7% (95% CI 14.7 +/- 5.6) of those surveyed included remuneration as contributing to their implementation of prevention activities in practice. CONCLUSIONS: Variations in physician attitudes could influence risk factor intervention. Interventions to change lifestyle are associated with uncertainty about patient compliance, efficacy of treatment, and ability to effect lifestyle changes.

Adult↗

Informatics methodologies for evaluation research in the practice setting.

A continuing challenge in health informatics and health evaluation is to enable access to the practice of health care so that the determinants of successful care and good health outcomes can be measured, evaluated and analysed. Furthermore the results of the analysis should be available to the health care practitioner or to the patient as might be appropriate, so that he or she can use this information for continual improvement of practice and optimisation of outcomes. In this paper we review two experiences, one in primary care, the FAMUS project, and the other in hospital care, the Autocontrol project. Each project demonstrates an informatics approach for evaluation research in the clinical setting and indicates ways in which useful information can be obtained which with appropriate feed-back and education can be used towards the achievement of better health. Emphasis is given to data collection methods compatible with practice and to high quality information feedback, particularly in the team context, to enable the formulation of strategies for practice improvement.

Cross-Sectional Studies↗

Gambiense trypanosomiasis: frequency of, and risk factors for, failure of melarsoprol therapy.

1083 patients with late-stage Trypanosoma brucei gambiense sleeping sickness were treated with melarsoprol in Nioki hospital, Zaire, between 1983 and 1990. Sixty-two (5.7%) died during treatment. Of the 1021 patients who survived the treatment, 63 (6.2%) subsequently relapsed, 58 (92%) of whom were diagnosed within 2 years of melarsoprol treatment. There was no evidence of an increase in the frequency of treatment failures during the study period, and the rate of relapses that we documented is comparable to that reported from Zaire more than 30 years ago. Relapses were more frequent among patients who had trypanosomes seen in the cerebrospinal fluid (CSF) at the time of the initial diagnosis (odds ratio [OR] = 2.76, 95% confidence interval [CI] = 1.65-4.63, P = 0.0001). Male patients had twice as many relapses as females (OR = 2.00, 95% CI = 1.19-3.36, P = 0.009), which was partly explained by males having trypanosomes in the CSF more often than females. There were important geographical variations in the frequency of relapses within the territory of the Nioki rural health zone, suggesting that the circulation of trypanosomes was geographically limited. Prednisolone treatment did not increase the risk of treatment failure, nor did decreasing the total dose of melarsoprol from 12 to 9 injections for patients with > or = 100 white blood cells/mm3 of CSF. Since patients with trypanosomes in the CSF are also those who are at the highest risk of melarsoprol-induced encephalopathy, more aggressive treatment regimens cannot be recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Epidemiological evidence for immunity following Trypanosoma brucei gambiense sleeping sickness.

In order to investigate whether protective immunity appears after Trypanosoma brucei gambiense sleeping sickness, we undertook a retrospective cohort study of 3 remote villages in central Zaire (total population 1431), in which 38% of all adults had a past history of human African trypanosomiasis. Among adults previously diagnosed with trypanosomiasis and treated, the risk of a second episode of trypanosomiasis during the 10 years period of observation was only 15% (with a 24 months refractory period) and 30% (without a refractory period) of the risk of a first episode in adults never previously diagnosed. We could not demonstrate a similar difference among children, to some extent because only a few of them were diagnosed for a first time with trypanosomiasis. Our findings suggest that very significant immunity appears after Gambian sleeping sickness, and that developing a vaccine against this subspecies of trypanosomes is biologically plausible.

Adolescent↗

Risk factors for encephalopathy and mortality during melarsoprol treatment of Trypanosoma brucei gambiense sleeping sickness.

This paper reviews the incidence of, and risk factors for, drug-induced encephalopathy and mortality (from all causes) during treatment with melarsoprol of 1083 patients with Trypanosoma brucei gambiense sleeping sickness in Nioki hospital (Zaire) between 1983 and 1990. Sixty-four patients (5.9%) developed encephalopathy and 62 (5.7%) died: 43 from reactive encephalopathy and 19 from other causes. Univariate and multivariate analyses showed that the administration of prednisolone reduced significantly the incidence of encephalopathy and mortality during treatment, especially in patients with trypanosomes observed in the cerebrospinal fluid (CSF) and/or with a CSF white blood cell (WBC) count of 100 or more per mm3. The risk of encephalopathy was associated more strongly with the CSF WBC count than with the presence of CSF trypanosomes. In the subgroup of patients with a CSF WBC count of 100 or more mm3, changing the melarsoprol regimen to 3 series of 3 injections instead of 3 series of 4 injections halved the mortality rate during treatment. Treatment of patients who do develop reactive encephalopathy with the heavy metal chelator dimercaprol, in addition to intravenous steroids and anticonvulsants, may be harmful. The data suggest that a further reduction of the total dose of melarsoprol may decrease toxicity without jeopardizing efficacy.

Adolescent↗

Familial aggregation of Trypanosoma brucei gambiense trypanosomiasis in a very high incidence community in Zaire.

Familial aggregation of Trypanosoma brucei gambiense human African trypanosomiasis (HAT) was investigated in 3 adjacent villages of central Zaire where 318/1431 inhabitants had previously suffered from HAT. Neither spatial nor familial aggregation was detected when analysing the distribution of cases in the whole community using Poisson, negative binomial and pairwise odds ratio models. However, clustering of cases was observed when specific familial relationships were examined. The risk of HAT for a child was significantly increased if the mother had also had HAT, but it was not influenced by a past history of HAT in the father. Sisters and brothers of cases of HAT had a higher risk of HAT than siblings of individuals who had never had HAT, but no such association was documented for half-sisters and half-brothers. Among married couples, a past history of HAT in one spouse had no impact on the other spouse's risk of HAT. Indirect arguments suggested that familial clustering was a consequence of shared exposure, either sequential or simultaneous, rather than of genetic susceptibility. The existence of familial clustering should be kept in mind when implementing passive or active case-finding activities.

Adolescent↗

Implementation of a province-wide computerized network in Quebec: the FAMUS Project.

General practitioners have busy schedules and are accustomed to working autonomously. But they will take an interest in research issues that could increase their efficiency or improve patient care. The use of medical informatics tools to facilitate collaborative research networks requires that participants accept the tools. This article describes the implementation of a province-wide computing network and discusses the opportunities afforded by the creation of a large central database documenting the process of care.

Ambulatory Care Information Systems↗