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Biomedical subjects

S M Debanne

Publications and source records attributed to S M Debanne.

At least 19 recordsLinked to original sources
PubMed2000

Association of Alzheimer's disease and smoking: the case for sibling controls.

OBJECTIVES: To study the association between cigarette smoking and Alzheimer's Disease (AD). DESIGN: Intrafamily case-control, with sibling controls and a variable number of controls per case. SETTING: AD cases were identified through the Research Registry of the University Hospitals of the Cleveland/Case Western Reserve University Alzheimer Center. PARTICIPANTS: Study subjects were 86 probable AD cases (index cases) and all of their full siblings, alive or dead, aged > or = 50 years, a total of 238 subjects. MEASUREMENTS: Exposure for each individual was ascertained with a questionnaire answered by several informants. Cognitive status of siblings of the AD cases (impaired or intact) was ascertained by telephone using validated instruments. Diagnosis of dementia in cognitively impaired siblings of index cases was not attempted. RESULTS: Chi-square analysis tested for departure from a random distribution of disease across smokers and nonsmokers within families. No significant departure was found utilizing all families (P > .40) nor utilizing those families where only the index case was affected (P > .90). Conditional logistic regression evaluated the association within families, controlling for age, sex, and education. Analyses both included and excluded secondary cases of cognitive impairment. No association was found between smoking and disease (OR = 1.26; 95% confidence interval, 0.66-2.42, and OR = 1.42; 95% confidence interval, 0.69-2.89, respectively). CONCLUSIONS: No significant association was found between smoking and cognitive status. Further, analyses based on the comparison of persons with AD with their unaffected siblings also suggest that smoking does not decrease the risk of AD.

Aged↗
PubMed1998

Statistical certification of eradication of poliomyelitis in the Americas.

The last confirmed case of paralytic poliomyelitis due to indigenous wild poliovirus in the Americas occurred in Peru in 1991. In 1994 the International Commission on Polio Eradication of the Pan American Health Organization (PAHO) deemed eradication of polio from the area to have occurred, based on its strategic efforts and the observed results. A mathematical model is presented here which relates the time elapsed since that last detected case of paralytic poliomyelitis caused by wild poliovirus to the probability that the transmission of indigenous wild poliovirus has been stopped. The appropriateness of applying the model to various geographical areas of the Americas is investigated using data about the occurrence of confirmed cases of polio since 1984, the time of the eradication initiative adopted by PAHO. The model suggests that if four year have elapsed since the last reported confirmed case of polio caused by wild poliovirus, and no other confirmed cases have been identified, the probability of undetected indigenous wild poliovirus transmission is less than 5%. An important assumption is that the eradication strategy implemented by PAHO has yielded steady improvements. A consequence of this approach is that the annual probabilities of persistence given by the model are conservative, in the sense of being higher than the true, but unknown a priori probabilities, and more so with each passing year. It is thus seen that the model results are compatible with the conclusion reached by PAHO in 1994. The model takes into account the intensity of surveillance of each country in the region, measured by the corresponding rates of acute flaccid paralysis (AFP). Because importations of wild poliovirus may occur from other regions of the world, surveillance efforts are being maintained in the Americas until global eradication has been achieved.

Americas↗
PubMed1997

Estimation of the annual risk of tuberculosis infection for white men in the United States.

The annual risk of tuberculous infection for white men in the United States was estimated from published tuberculin surveys and found to be related to tuberculosis incidence as reflected in the annual case rate during the past 3 decades, with a constant ratio of approximately 150. It is currently estimated to be 0.03%/year. The technique developed for this estimation is not complex and should be applicable to other segments of the population for which suitable data are available.

Databases, Factual↗
PubMed1997

Religiosity and perceived rewards of black and white caregivers.

Using data from a larger study of caregivers of the elderly, this study explores the extent to which religiosity variables function as mediators of the effects of situational/demographic factors on perceived caregiver rewards. In the parent project, random digit dialing was used to select 136 Black and 255 White caregivers of community-dwelling elders for face-to-face interviews. Regression analyses revealed that Black caregivers perceived higher levels of rewards than Whites and the relationship between race and perceived rewards was mediated by comfort from religion and prayer. Blacks and Whites with more education reported fewer perceived rewards than caregivers with less education.

Adaptation, Psychological↗
PubMed1997

Validation of a Telephone Cognitive Assessment Battery.

OBJECTIVE: To present and evaluate an instrument, the Telephone Cognitive Assessment Battery (TCAB), designed to be administered over the telephone to assess the cognitive status of older individuals. The TCAB addresses mental status, reasoning and executive ability, primary and secondary memory, and language. It consists of six neuropsychological tests and takes approximately 15 to 20 minutes to complete. DESIGN: The instrument is evaluated with a comparative cross-sectional design, with data collected both prospectively and retrospectively. SETTING: The University Hospitals of Cleveland/Case Western Reserve University Alzheimer Center Research Registry. PARTICIPANTS: Forty Alzheimer's Disease cases selected from among those most recently recruited into the Registry and 40 cognitively intact Registry controls. Controls were selected randomly so that the two groups had similar distributions of age, sex, and education. MEASUREMENTS: The cognitive status of all participants was assessed utilizing both the TCAB and the usual in-person Registry evaluation, which includes medical history data and in-person assessment of cognitive status. In order to measure the potential learning effect of repeated testing, half of the cases and half of the controls were recruited and assessed over the telephone with the TCAB before their in-person Registry evaluation (with a waiting period of at least 2 weeks between evaluations), whereas the other two halves received the TCAB after they had become part of the Registry. The TCAB was administered to all participants by a single investigator. Two clinical evaluators, blinded to the Registry diagnosis of the subjects, independently classified the subjects as cognitively impaired, normal, or questionable on the basis of the results of the TCAB and a brief listing of medical illness and depressive symptoms. A final classification was achieved through consensus and subsequently compared with the Registry diagnosis, taken here to be the gold standard. RESULTS: Test scores of subjects assessed by TCAB before receiving the in-person assessment were compared with those of subjects receiving the in-person assessment first. There were no significant differences between mean scores of the two groups (those with TCAB first and those with TCAB last) for either cases or normal controls. High values of the kappa statistic were obtained for the two initial evaluators of the TCAB classification, demonstrating excellent interrater reliability. Regarding the reconciled TCAB classification, the ability of the TCAB to correctly classify subjects according to cognitive status, while controlling for potential confounders such as age and educational level, was assessed by means of discriminant analysis techniques. Knowledge of the TCAB classification and age allowed the correct classification of 95% of the participants; this was not significantly improved by knowledge of other potential determinants. Sensitivity and specificity were calculated under two schema for classifying those subjects in the "questionable" category. Positive and negative predictive values of the TCAB were computed assuming a prevalence of cognitive impairment of 10% in the older population. High negative predictive values (over 99%) were obtained under both schema, whereas the positive predictive values were seen to be more dependent on the classification of questionables. CONCLUSION: Research studies involving ascertainment of cognitive status of older people, particularly those that require periodic follow-up, such as those focusing on healthy aging, commonly suffer from lack of representativeness of subjects, often brought about by problems related to mobility of potential participants. It is also crucial that normal individuals who are recruited initially to serve as controls in epidemiologic studies of dementing illnesses be reevaluated periodically, and this may be hindered by the same obstacles. (ABSTRACT TRUNCATED)

Aged↗
PubMed1996

Storing sparse and repeated data in multivariate Markovian models of tuberculosis spread.

Through the use of appropriate sparse storage techniques, we were able to reduce memory usage in a multivariate Markovian model for the spread of tuberculosis in the United States through the year 2010. A straightforward software implementation of the model would have required approximately 2.5 x 10(9) bytes of storage for the population of each year being modeled and approximately 1.3 x 10(14) bytes of storage for each year-to-year set of transition probabilities. We were able to reduce memory usage in the model by 96% for cross-sectional population data and over 99.9% for transition probability data. Data structure initialization time for population data was increased by a factor of 16.48 and lookup time for population data was increased by a factor of 11.3 over times required for an array implementation. For transition data the initialization and lookup times were increased by negligible factors. This work was done under contract from the Centers for Disease Control and the Association of Teachers of Preventive Medicine.

Centers for Disease Control and Prevention, U.S.↗
PubMed1996

Smoking and cognitive impairment: a population-based study.

OBJECTIVE: To test the hypothesis that there is an inverse relationship between smoking and cognitive impairment by examining the prevalence and incidence of such impairment in a representative cohort of older urban residents. DESIGN: Survey follow-up with three interviews over a 4-year period. SETTING: City of Cleveland, Ohio. PARTICIPANTS: Six hundred forty-seven survivors of a population-based, multi-stage probability sample of urban residents, aged 74 years and older in 1984. MEASUREMENTS: Past and present cigarette smoking was measured in 1984 by direct questioning. Cognitive impairment was measured in 1984, 1987, and 1988 by the 10-item Short Portable Mental Status Questionnaire. Mortality was determined at each interview date, and death certificates were obtained. Data were analyzed by univariate analysis, stratified analysis, and multivariate logistic regression. RESULTS: There were 99 cases of cognitive impairment at baseline among 628 individuals for whom complete data were available. Crude data suggest that the prevalence of cognitive impairment was lower among smokers than among non-smokers, but logistic regression, adjusted for age, income, and gender, showed this difference to be non-significant, OR 0.73; 95% CI (0.42, 1.29). Fifty-one new cases of cognitive impairment occurred during the 4-year observation period. Neither the crude data nor logistic regression showed any significant relationship between smoking and the incidence of cognitive impairment, OR 1.03; 95% CI (0.54, 1.99). Four-year mortality did not differ significantly between these older smokers and non-smokers, but smokers died at a relatively younger age and were more likely to die of diseases associated with smoking.

Aged↗
PubMed1992

Abnormal labor and infant brain damage.

OBJECTIVE: To determine whether arrest disorders result in increased neurologic abnormalities in infancy or childhood. METHODS: Four hundred thirteen infants with arrest disorders as defined by Friedman criteria were matched to a similar population without arrest disorders. The median length of follow-up was 6 years for the study infants and 5.07 years for the controls. The numbers of children with abnormalities in the groups with and without arrest disorders, as well as the specific abnormalities encountered, were stratified by method of delivery. RESULTS: Thirty neurologic abnormalities were found in the arrest group and 37 in the control group; thus, the null hypotheses could not be rejected. In addition, although the control group was not followed as long as the study population, the diagnosis of abnormalities was more frequent in the later years in the controls. This suggests that had the follow-ups been equal, there would have been stronger proof that arrest by itself was not associated with infant brain damage. CONCLUSION: Our study confirms that labor diagnoses of prolonged active phase, protractions or arrests, and failure to descend are not associated with increased neurologic abnormalities. Delivery by cesarean or vaginal birth and use of oxytocin are not factors in the etiology of major brain damage.

Brain Damage, Chronic↗
PubMed1989

Arrest disorders and infant brain damage.

In the past, difficult labors have been associated with maternal and infant damage. Today, changing patient management is associated with less trauma and more frequent use of cesarean births to avoid potential fetal neurologic damage. In this report, arrests of dilatation and descent and prolongation of the decelerative phase of labor were reviewed with respect to the later appearance of brain damage in infants after 2 years of age, in association with obstetric interventions including cesarean birth, forceps, and oxytocin. Charts of 413 infants born after abnormal labors were studied. Log-linear analysis was performed to determine the contribution of method of delivery and oxytocin use to the presence of neurologic abnormalities. Statistical testing ruled out the presence in the model of a three-way interaction, and excluded the two-way interactions of neurologic abnormalities-oxytocin use and neurologic abnormalities-method of delivery. Chi-square tests of partial association and marginal association for the delivery-oxytocin interaction yielded values of 33.54 (P less than .0001) and 33.78 (P less than .00001). This model asserted that method of delivery and use of oxytocin were unrelated to the presence of neurologic abnormalities, but were related to each other.

Birth Weight↗
PubMed1987

Male reproductive assessment of the rubber accelerator N-oxydiethylene thiocarbamyl-N-oxydiethylene sulfenamide in rats.

The rubber accelerator N-oxydiethylene thiocarbamyl-N-oxydiethylene sulfenamide (OTOS) was evaluated to determine its potential to cause reproductive effects. No evidence of a compound-related effect on mating, fertility, gestation length, number of implants or live births, pup growth, and survival was observed using Sprague-Dawley rats. Furthermore, light and electron microscopy of the testes from the high-dose males failed to reveal any morphological changes compared to the controls. Groups of 12 male Sprague-Dawley rats were continuously administered diets containing 0, 60, 200, or 600 ppm OTOS for 12 weeks. Following 56 days of exposure, the males were subsequently cohoused nightly with two females for a maximum of 21 days. During this mating period, males continued to receive control and OTOS-containing diets; however, feeders were removed for nightly cohabitation. Although a 4 to 8% reduction in body weight was observed in the 600 ppm animals, statistical significance was reached only at the end of the first week of treatment. In the 60 and 200 ppm males body weights generally were slightly elevated compared to the control, with the 60 ppm body weights showing statistically significant differences during Weeks 5 to 7 of exposure.

Animals↗
PubMed1986

Prognostic factors in vitrectomy for epiretinal membranes of the macula.

A retrospective multivariate analysis of 264 consecutive cases of vitrectomy for removal of epiretinal membranes of the macula was performed. Two main preoperative prognostic factors were identified that were associated with the visual outcome of surgery: (1) the preoperative visual acuity, and (2) the duration of blurred vision before surgery. Discriminant functions constructed using these two factors allowed correct classification of eyes into an outcome group with good visual acuity with a 69% accuracy, and an 80% accuracy in classifying eyes into a group showing significant improvement in the level of visual acuity. Eyes that began with vision better than 20/100 tended to have slightly better postoperative visions than eyes with poorer preoperative visual acuity. However, eyes with worse preoperative vision tended to improve the greatest amount after surgery. Eyes with a longer history of blurred vision had poorer visual acuity after surgery and also less improvement in vision. Other statistically significant prognostic factors were identified; however, they did not appreciably improve the accuracy of the discriminant function in predicting visual outcome.

Adolescent↗
PubMed1986

Adjusting for confounding with statistical software packages.

Much computer use in support of clinical research involves the execution of standard statistical packages. Prenatal risks, such as maternal substance use, may be related to outcomes, such as lowered birthweight for gestational age, using multiple regression. In standard stepwise multiple regression, variance shared by two risks is attributed to the first variable entered in the equation, potentially underestimating the effect size of subsequently entered variables. A novel solution to this problem, adapted from the epidemiologic technique of calculating attributable risk, is applied in the multivariate setting and produces more appropriate estimates of the effect sizes of independent risks. An example of this method, using a standard statistical package, is presented.

Alcohol Drinking↗
PubMed1986

Field evaluation of enzyme-linked immunosorbent assay for the serodiagnosis of tuberculosis.

An enzyme-linked immunosorbent assay (ELISA) was evaluated as a serodiagnostic test for active tuberculosis in La Paz, Bolivia. ELISA was compared with sputum smear in 277 persons presenting to the Instituto de Torax and was used for screening in 1,458 military personnel. The test was performed under field conditions on 4-microliter samples of capillary blood obtained by finger prick. ELISA was found to have a sensitivity of 69% and a specificity of 88%. Sputum smear had a sensitivity of 79% and a specificity of 100%. ELISA was found to have undiminished sensitivity and specificity in patients who were sputum-negative, and the two tests could be combined to achieve a sensitivity of 92% and specificity of 88%. Positive and negative predictive values were highest for populations with tuberculosis prevalences in the range of that seen among patients presenting to the Instituto de Torax in Bolivia, but ELISA also led to the diagnosis of tuberculosis in 5 of 1,458 soldiers tested in the screening program.

Adolescent↗
PubMed1985

Evaluation of statistical methodologies for estimation of median effective dose.

A comparison is made of statistical techniques currently in use for analysis of quantal assay data. The discussion focuses on the choice of the functional model to use in the description of the tolerance distribution for the estimation of the median effective dose and in the contrast between exact and graphical methods of estimation for a given choice of model. The data used to illustrate these focal points are derived from test data from biological assays performed at the University of Pittsburgh. A criterion for making a choice among functional models based on the significance of the dose-response relationship and the length of the fiducial limits for the median effective dose is proposed. It is also shown that graphical methods can lead to results similar to those arrived at through exact calculations where the data fit model assumptions but can lead to erroneous conclusions where this is not the case.

Animals↗
PubMed1985

Enzyme-linked immunosorbent assay using Mycobacterium tuberculosis antigen 5 and PPD for the serodiagnosis of tuberculosis.

Enzyme-linked immunosorbent assays (ELISA) of immunoglobulin G antibody to Mycobacterium tuberculosis antigen 5 and tuberculin purified protein derivative (PPD) were assessed for the serodiagnosis of tuberculosis in 41 patients with active tuberculosis, 19 patients with inactive tuberculosis, and 59 healthy control subjects. Patients with active tuberculosis were studied serially at monthly intervals following the initiation of therapy. When contrasted with our earlier studies of sera from patients in Bolivia and Argentina, serum titers in Cleveland patients with active tuberculosis were somewhat lower. Geometric mean titer in patients with active tuberculosis was 1:68 with antigen 5 and 1:46 with PPD. Titer was correlated with patient age, male sex, extent of tuberculosis, and history of prior tuberculosis. However, these associations were not statistically significant. During monthly follow-up for 16 months after the initiation of therapy, ELISA titers remained essentially stable. Thus, no convincing evidence was acquired to support the hypothesis that higher titers in sera from South American patients related to more chronic or more extensive disease. Receiver operating characteristics of ELISA with antigen 5 were better than those obtained using PPD and were similar to those reported by others for sputum smear. In a situation where tuberculosis screening is warranted, ELISA with antigen 5 might have a place if it recognizes a different population than does sputum smear.

Adult↗
PubMed1985

Long-term follow-up after recovery from acute myocardial infarction. Observations on survival, ventricular arrhythmias, and sudden death.

A long-term 12-year follow-up of 248 patients surviving acute myocardial infarction indicated a cumulative survival of 89%, 68%, 53%, and 45% for 1, 5, 10, and 12 years, respectively. When patients were assessed with five routinely obtained clinical factors, significant prognostic stratification of high- and low-risk survival groups extended throughout the follow-up period. Sudden cardiac death was found to be twice as frequent as nonsudden cardiac death, but a significant relationship between sudden death and complex ventricular ectopic beats could not be defined. The extent of complex features of ventricular ectopic beats such as pairs, multiform, repetitive, and R-on-T was inversely related to survival. During the first year after acute myocardial infarction, frequency of ventricular ectopic beats was also inversely related to survival. A long-term effect of frequency on survival, however, could not be demonstrated.

Actuarial Analysis↗