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Biomedical subjects

D Commenges

Publications and source records attributed to D Commenges.

At least 91 records · Page 5Linked to original sources
PubMed1989

Loss of maternal measles antibody during infancy in an African city.

Measles epidemics with 20% of the cases under nine months of age continue to occur in Brazzaville, Congo, even though measles vaccination coverage was 77% in the 12- to 23-month age group in 1986. In order to estimate the duration of passive immunity against measles, we conducted a serologic survey of infants aged 2 to 9 months. Measles antibody was measured from capillary blood with the plaque inhibition test. An antibody titre of 40 milli-International Reference Units per ml of serum (mIRU/ml) or less was defined as seronegative. Among the 252 infants studied, the proportion with detectable antibody dropped from 95.8% at 2 months of age to 48.5% at 4 months of age, and to 8.2% in the 7-8 month age group. A simple logistic model with age as the only variable provided an excellent fit to the observed values. Between the ages of 8 and 28 weeks, there was an almost steady decline of approximately 4.7% per week in the proportion of infants who were seropositive. These findings suggest that loss of maternal measles antibody during infancy might be faster than reported in other African populations. Giving measles vaccine to infants before the age of nine months currently recommended by the Expanded Programme on Immunization may be useful in some populations. Further studies of seroconversion and impact on measles are needed.

Age Factors↗
PubMed1989

Evaluation and simplification of the World Health Organization clinical case definition for paediatric AIDS.

The World Health Organization (WHO) clinical case definition for paediatric AIDS was tested during a 1-month period on 221 consecutive hospitalized children in Kigali, Rwanda. Relevant clinical features not included in the WHO case definition were also evaluated. Thirty-four out of the 221 children (15.4%) were HIV seropositive. Although the specificity of the WHO case definition was high (92%), the sensitivity and the positive predictive value (PPV) were low (41 and 48%, respectively). The following individual signs had a PPV at least equal to the complete WHO case definition: chronic diarrhoea (47%), respiratory distress secondary to lower respiratory tract infection (50%), oral candidiasis (53%), parotitis (67%), generalized lymphadenopathy (88%), and herpes zoster infection (100%). When logistic regression analysis was done on the nine variables included in the WHO case definition, confirmed maternal infection was the best predictive variable for HIV seropositivity in children (P less than 10(-5). We further excluded the serological status of the mother from the analysis and performed a stepwise logistic regression analysis on the 18 clinical signs and symptoms for which information had been collected. Those signs and symptoms contributing the most to the regression were: respiratory distress, chronic diarrhoea and generalized lymphadenopathy. Based on these findings, we propose a simplified clinical case definition for paediatric AIDS in Africa with better sensitivity, specificity and PPV than the WHO case definition. Further work is needed using this approach to develop case definitions useful for epidemiological surveillance and for case management.

Acquired Immunodeficiency Syndrome↗
PubMed1989

A strategy for analysing multiple risk factors with application to cervical pain syndrome.

When studying the possible effects of several factors in a given disease, two major problems arise: (1) confounding, and (2) multiplicity of tests. Frequently, in order to cope with the problem of confounding factors, models with multiple explanatory variables are used. However, the correlation structure of the variables may be such that the corresponding tests have low power: in its extreme form this situation is coined by the term "multicollinearity". As the problem of multiplicity is still relevant in these models, the interpretation of results is, in most cases, very hazardous. We propose a strategy--based on a tree structure of the variables--which provides a guide to the interpretation and controls the risk of erroneously rejecting null hypotheses. The strategy was applied to a study of cervical pain syndrome involving 990 subjects and 17 variables. Age, sex, head trauma, posture at work and psychological status were all found to be important risk factors.

Adult↗
PubMed1988

Prevalence and risk factors of recurrent cervical pain syndrome in a working population.

The prevalence and risk factors of recurrent cervical pain syndrome (CPS) was studied in 990 workers examined while undergoing their systematic annual visit of occupational medicine. A prevalence rate of 10.2% was obtained. Using a tree-structured logistic regression analysis, a strong association between age, sex, previous head trauma extension of the neck and strenuous muscular activity during work, and the risk of recurrent CPS was obtained. Finally, an inverse association between strenuous muscular activity during leisure time and the risk of recurrent CPS was found.

Adult↗
PubMed1988

Predictors of non-bedridden survival in dementia.

The present study examined non-bedridden survival in 105 patients diagnosed as demented (Alzheimer's disease, multi-infarct dementia, mixed dementia) in a neurological ward. Follow-up observations were made. During the first year, the cumulative mortality rate was 69% compared to a rate of 44% in the second year. The initial disability stage, as assessed by the Dementia Disability Scale, was found to be the only significant predictor of non-bedridden survival. The type of dementia, age, type of diagnosis, and post-hospitalization placement in an institution have not been found to be significant predictors of this evolution.

Adult↗
PubMed1988

[Predictive factors of the therapeutic result in the prevention of auricular fibrillation. Role of electrophysiological studies].

A population of 50 patients suffering from paroxysmal attacks of atrial fibrillation was studied prospectively to evaluate the prognostic value of 20 variables: 6 clinical variables: sex, age, cardiopathy, number of arrhythmic attacks, "vagal" triggering, failure of class IA antiarrhythmic agents; 3 echocardiographic variables: left ventricular diastolic diameter and percentage of fibre shortening, left atrial diameter; 6 basic electrophysiological data: threshold, refractory periods at 110 and 150/min, modalities of induction of a sustained arrhythmia; 4 results observed with an infusion of flecainide in doses of 2 mg/kg: arrest or persistence of the arrhythmia, whether or not it could be reinduced and value of refractory periods; doses of flecainide administered orally. With a mean +/- SD follow-up period of 7.7 +/- 7.3 months, preventive treatment with flecainide 233 +/- 7 mg failed in 16 patients (32 per cent) and succeeded in 34 patients (68 per cent). Analysis of Kaplan-Meier curves and use of Cox's multidimensional model showed that two electrophysiological data were of prognostic value: atrial effective refractory period, and non-inducibility of the arrhythmia after intravenous administration of flecainide. Thus, the probability of failure increases with the refractory period value and decreases with the non-inducibility of the arrhythmia.

Aged↗
PubMed1986

The formulae-relating slopes, correlation coefficients and variance ratios used to determine stimulus- or movement-related neuronal activity.

When recording single neuron discharge in an animal during the performance of a conditioned task, the functional interpretation of any change in neuronal activity after the conditioned stimulus but before the conditioned task is difficult. So far, such changes have been described as either stimulus- or movement-related. One way of classifying these two types of response has been to use the slope and correlation coefficient between the response latency and the behavioural reaction time. We show that this method is poor and propose a more valid approach.

Animals↗
PubMed1986

A program for analysing single neuron activity by methods based on estimation of a change-point.

A program for analysing the sequences of discharge of a single neuron is presented. This program performs the following tasks: it tests if there is a neuronal response after a stimulus, it estimates the response latency and, in the case of an experiment with a conditioned movement, it estimates the onset of the movement and gives indications about the functional role of the neuron by analysing the variances of the stimulus-response and response-movement times. The methods used have been developed by the authors and are based on the estimation of a change point. The basic methods are published elsewhere but some novelties are presented here, in particular a robust estimator of a variance ratio.

Action Potentials↗
PubMed1986

[Critical study of an interdisciplinary survey of urinary schistosomiasis in Burkina Faso].

We consider an approach to built on a score summarizing some demographic, social, geographic and parasitologic data for purpose of measuring the health impact of schistosomiasis. Operational definitions are given for the social, ecological and medical variables and for the survey design. Twenty villages from the Bam-Kongoussi district were kept for the survey, giving a sample of 11,396 peoples. The process of the survey is described. The overall response rate is 63%. The sensitivity of the survey's results in regard to the non-responses is considered along with the possibility to implement a call back survey.

Adolescent↗
PubMed1986

[Management of pregnancy at risk: evaluation of fetal movements, determination of total plasma estriol and placental lactogen hormone in relation to fetal heart rhythm].

The authors studied 50 at-risk pregnancies to decide how useful fetal movements were prognostically. They compared this method with electronic measurements of fetal cardiac rhythm. The results show that it is both sensitive and specific. The levels of total oestriols and of plasma placental lactogen hormone when compared with the fetal heart rhythm are just as specific and sensitive.

Estriol↗
PubMed1985

A quantitative analysis of stimulus- and movement-related responses in the posterior parietal cortex of the monkey.

The posterior parietal cortex (areas 5 and 7) in monkeys has been described as a higher association cortex and as such, area 5 has been attributed a complex somaesthetic function. More recently, a role in the formation of motor commands has been postulated for these two cortical areas. We have been particularly interested in the role area 5 neurons may have in movement initiation. Single neuron activity was recorded in area 5 during the performance of a trained forelimb movement in monkeys and neuronal responses which occurred prior to movement were observed. In the present report, we have examined the neuronal discharge data trial by trial using a technique of data analysis which enabled us to separate the changes in neuronal activity into stimulus- or movement-related responses. Both stimulus- and movement-related responses were identified. The stimulus-related responses were not simple sensory responses since they were also influenced by the timing of the onset of movement. These results suggest that certain area 5 neurons may be involved in the linking of sensory inputs with motor outputs. Cerebrocerebellar loops may be a pathway in this linkage. The latencies of the movement-related responses were such that corollary discharge from the motor cortex may have played a role in this activity. Such corollary discharge may be a form of information used by the animal to execute movement in the absence of peripheral feedback.

Afferent Pathways↗
PubMed1984

Respiratory water loss as a function of ventilatory or environmental factors.

Since expired gas is not water-saturated (Ferrus et al., 1980, Respir. Physiol. 39: 367-381), its water content should depend on biological or environmental factors other than expired gas temperature. In order to verify this hypothesis, multiple linear regression relationships between MEH2O, the mass of water expired per litre of BTPS ventilated gas and respiratory frequency (f) or period (TR), tidal volume (VT), ventilation (V), temperature of inspired gas (TI), density of inspired gas mixture (rho I), partial pressure of water in inspired gas (PIH2O) were computed from 345 experiments performed on 7 subjects. This analysis shows that MEH2O is positively and significantly correlated to TI (0.22 mg . dm-3 . degrees C-1), to PIH2O (0.14 mg . dm-3 . Torr-1), and to TR (0.87 mg . dm3 . s-1). MEH2O is negatively and significantly correlated to f (-0.27 mg . dm-3(cy . min-1)-1) to rho I (-0.06 mg . dm-3(g . dm-3)-1) and to V (-0.09 mg . dm-3(dm3 . min-1)-1). There is no statistical correlation between MEH2O and VT. It is concluded that the respiratory water loss depends to a large degree on respiratory or environmental conditions. This dependence supports the previously published results suggesting that expired gas is not water saturated.

Environment↗
PubMed1983

A statistical method for the estimation of neuronal response latency and its functional interpretation.

The functional role of many central nervous structures has been inferred from the temporal relationship of a neuronal response with the different sensory and motor events in an experimental design such as when an animal performs a trained movement in response to a conditioned stimulus. However, this kind of data analysis leads to problems in estimating the occurrence and latency of any neuronal response. We examine these problems and propose a novel technique of data analysis to estimate the point of change in a sequence of neuronal discharge. Furthermore, data can be tested to see whether the neuronal response is related to the conditioned stimulus or the motor act. The method can also be used in the simple situation of determining the latency of a neuronal response after a stimulus.

Animals↗
PubMed1983

Long-term prognosis in two forms of childhood epilepsy: typical absence seizures and epilepsy with rolandic (centrotemporal) EEG foci.

Findings in children seen between 1955 and 1965 during the year of onset of typical absence seizures (90 patients) or rolandic epilepsy (79 patients) were analyzed by actuarial methods. One hundred and eighteen patients were followed for more than 15 years. Rolandic epilepsy is a true benign epilepsy ending with puberty. Although school and family problems are common during the acute stage of the disease, the social adaptability of such patients is excellent. We considered only typical absences occurring as a first epileptic sign in normal children. Myoclonic or atonic absences have a poor prognosis. Many patients with simple and automatic absences experience remission 15 years after withdrawal of medication. The overall cessation rate in those experiencing absences was only 57.5%, however, and 36% of patients developed tonic-clonic seizures. Social adaptability was often inadequate. Simple and automatic absences (constituting a homogeneous group) are not truly a benign form of epilepsy, even though prognosis for those afflicted is better than that for those with other forms of primary generalized epilepsy.

Adolescent↗