HEPA respirators and tuberculosis in hospital workers.
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Costs and Cost Analysis↗
Biomedical subjects
E Sobel
Publications and source records attributed to E Sobel.
Extrapyramidal signs and psychiatric symptoms predict faster cognitive decline in Alzheimer's disease.
OBJECTIVE: To identify clinical predictors of cognitive decline in Alzheimer's disease. DESIGN: A cohort of patients was followed up longitudinally and the likelihood of arriving at two cognitive end points was assessed using the Cox proportional hazards model and eight explanatory variables. SETTING: Subjects were chosen from patients examined for memory loss at two medical centers affiliated with the University of Southern California, Los Angeles. PATIENTS: The sample included 135 patients who met National Institute for Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for probable or definite Alzheimer's disease, had initial Mini-Mental State Examination (MMSE) scores of 14 or greater, and had been seen on at least two occasions. MAIN OUTCOME MEASURES: The time to reach either of two end points, ie, MMSE score of 8 and a decline of six points on the MMSE, was assessed. RESULTS: After controlling for initial severity of dementia (eg, by dividing the sample into mild and moderate dementia subgroups or by using the individually defined end point of a six-point decline on the MMSE), the presence at baseline of extrapyramidal signs (risk-hazard ratio, 10.34; 95% confidence interval, 2.76 to 38.68; P = .0005), agitation (risk-hazard ratio, 2.98; 95% confidence interval, 1.35 to 6.61; P = .007), and hallucinations (risk-hazard ratio, 3.85; 95% confidence interval, 1.35 to 11; P = .01) predicted a shorter time to reach an end point. CONCLUSIONS: After controlling for initial severity of dementia, the presence of extrapyramidal signs and behavioral symptoms (agitation and hallucinations) significantly predict faster cognitive decline. These findings may reflect the effects of neuroleptic medication, the presence of underlying diffuse Lewy body disease, or alterations in biogenic amine systems.
Aged↗
Exposure to magnetic fields among electrical workers in relation to leukemia risk in Los Angeles County.
To address the hypotheses that electrical workers are exposed to higher magnetic fields and are at higher risk of leukemia than nonelectrical workers, we performed a registry-based case-control study among men aged 20-64 years with known occupation who were diagnosed with cancer in Los Angeles County between 1972 and 1990. Controls were men with cancers other than those of the central nervous system or leukemia. Magnetic field measurements on workers in each electrical occupation and in a random sample of occupations presumed to be nonelectrical were used to estimate magnetic field exposures for each occupation. Among men in electrical occupations, 121 leukemias were diagnosed. With the exception of electrical engineers, magnetic field exposures were higher among workers in electrical occupations than in nonelectrical occupations. A weakly positive trend in leukemia risk across average occupational magnetic field exposure was observed (odds ratio [OR] per 10 milligauss increase in average magnetic field = 1.2, 95% confidence interval [CI] 1.0-1.5). A slightly stronger association was observed for chronic myloid leukemia, although only 28 cases occurred among electrical workers (OR 10 milligauss increase = 1.6, 95% CI = 1.2-2.0). The results were not materially altered by adjustment for exposure to several agents known or suspected to cause leukemia. Although not conclusive, these results are consistent with findings from studies based on job title alone that electrical workers may be at slightly increased risk of leukemia.
Adult↗
A multifactorial analysis of risk factors for recurrence of ischemic stroke.
BACKGROUND AND PURPOSE: Risk factors for stroke recurrence have usually been evaluated as single variables. This study is a multivariate analysis of five risk factors (hypertension, myocardial infarction, cardiac arrhythmia, diabetes mellitus, and transient ischemic attacks) for second stroke after an initial ischemic stroke. METHODS: Six hundred twenty-one patients with an acute ischemic stroke were followed prospectively first at 4 months after onset and then at approximately 6-month intervals until death, recurrence of stroke, or the end of the study. The five risk factors were measured at each visit. A Cox multifactorial regression analysis was conducted using the risk factor status at enrollment and adjusted for age and sex. RESULTS: Follow-up averaged 24 months (range, 1 to 48 months). Men comprised 52% of the cohort and were slightly older; 97% of the cohort was white, and 57% had multiple risk factors. Hypertension occurred in 59%, cardiac arrhythmia in 47% (of which 16% had atrial fibrillation), diabetes mellitus in 30%, myocardial infarction in 25%, and transient ischemic attacks in 18%. Only history of hypertension and atrial fibrillation by electrocardiogram were associated with increased risk of second stroke independently and significantly (P = .01 and P = .04, respectively). CONCLUSIONS: Among the five factors analyzed, control of hypertension and atrial fibrillation appear to offer the greatest chance of reducing risk of stroke recurrence after an ischemic stroke.
Aged↗
Hypertension and risk of stroke recurrence.
BACKGROUND AND PURPOSE: Hypertension is a risk factor for initial stroke, but its relation to stroke recurrence is unclear. Therefore, we sought to analyze the effect of hypertension and its control on risk of stroke recurrence. METHODS: Within 1 month of onset, a population-based cohort of 662 patients from the Lehigh Valley with an initial stroke were enrolled. Hypertension was determined at enrollment by history. Blood pressure was also measured at enrollment and at each follow-up at 4- to 6-month intervals for up to 48 months (mean, 24 months). Stroke recurrence was verified by history, examination, and review of medical reports. Various criteria for control of blood pressure were defined. History of hypertension, measured blood pressure, and its control were analyzed in relation to stroke recurrence frequency using Kaplan-Meier and univariate, multivariate, and time-dependent Cox proportional hazards models. RESULTS: At enrollment, 59.4% of the cohort had a history of hypertension and 81 patients had a second stroke. Those with a history of hypertension had a significantly higher stroke recurrence rate than those without such a history (P = .01). Among those with measured diastolic blood pressure at enrollment > or = 95 mm Hg, 43% had a stroke recurrence by the end of the study compared with only 19% below this cutoff (P = .005). Recurrence risk was reduced in a multivariate analysis as quality of diastolic blood pressure control increased (relative risk = 8.4, 3.9, and 2.0 among those with poor, fair, and good control, respectively, compared with nonhypertensive subjects). Systolic blood pressure and its control appeared less or not significantly associated with stroke recurrence. CONCLUSIONS: History of hypertension and elevated measured diastolic pressure after the initial stroke were associated with an increased risk of second stroke. Controlling diastolic pressure substantially reduced this risk.
Age Factors↗
Acute chest pain in African Americans: factors in the delay in seeking emergency care.
OBJECTIVES: African Americans have been shown to have longer delay times than the majority population in seeking care for acute cardiac problems. The purpose of this study was to determine whether socioeconomic factors affect delay times. METHODS: Structured interviews were administered to 254 African Americans admitted to a public hospital and 194 African Americans admitted to a private hospital for suspected acute myocardial infarction. RESULTS: Patient characteristics found by multiple regression analysis to affect decision-making and travel time for care-seeking were structural access to care, persistence of symptoms, degree of incapacitation, consultation with a layperson, consultation with medical professionals, and mode of transportation. CONCLUSIONS: Within-group differences were found to be related to socioeconomic status. Strategies to increase knowledge about heart attack symptoms, improve access to care, and improve the socioeconomic status of at-risk African Americans are indicated.
Acute Disease↗
Control of HLA-DR antigen expression by gamma-interferon: separate signal transduction mechanisms in malignant and nonmalignant human thyroid cells.
Three intracellular signal transduction pathways have been found to be utilized by gamma-interferon (IFN-gamma) in the induction of HLA-DR in several cell types, mainly monocytes/macrophages and B-cells: the protein kinase A (PKA); Ca(2+)-calmodulin; and protein kinase C (PKC) pathways. In this study, we investigated the role of these pathways in IFN-gamma-induced HLA-DR expression in normal and neoplastic human thyroid cells. The PKA pathway seemed to inhibit both neoplastic and normal IFN-gamma-induced HLA-DR expression; addition of thyroid-stimulating hormone to normal thyroid cells, as well as 8-bromo cyclic AMP and forskolin to normal and neoplastic cells, reduced the amount of IFN-gamma-induced HLA-DR. Moreover, H-8, a PKA inhibitor, enhanced such IFN-gamma-induced HLA-DR expression. The calcium-calmodulin pathway does not seem to play a role in IFN-gamma-induced HLA-DR expression in normal and neoplastic thyrocytes, since the Ca-ionophore A23187, EGTA, and the calmodulin antagonist, W-7, neither induced HLA-DR nor showed any effect on HLA-DR expression induced by IFN-gamma. Alone, phorbol 12-myristate 13-acetate, a PKC activator, did not induce HLA-DR on thyroid cells. However, its addition to neoplastic cells together with IFN-gamma caused a synergistic elevation of the expressed HLA-DR, whereas it significantly inhibited IFN-gamma-induced HLA-DR in normal thyrocytes. TPA had to be added before or together with IFN-gamma for optimal function. If added more than 6 h after IFN-gamma, TPA was not effective. An inactive TPA analogue did not affect HLA-DR induction, while an active analogue mimicked TPA. Staurosporine, a PKC inhibitor, reduced the TPA enhancing effect in neoplastic thyrocytes and cancelled TPA inhibition in normal cells. Moreover, when added to IFN-gamma without TPA in normal thyroid cells, staurosporine increased 3- to 4-fold the amount of HLA-DR. Thus, in normal thyroid cells the PKC pathway is activated by IFN-gamma and inhibits HLA-DR expression. In neoplastic thyrocytes, although IFN-gamma does not induce HLA-DR via PKC, this pathway augments HLA-DR expression.
Alkaloids↗
Gender differences on a brief measure of cognitive functioning in Alzheimer's disease.
OBJECTIVE: We evaluated scores on a brief psychometric screening instrument--the Mini-Mental State Examination (MMSE)--for possible effects of gender, hypothesizing that women with Alzheimer's disease (AD) would perform more poorly than men. A significant gender difference was to be explored with post hoc item analyses. DESIGN: Case-study design. A hierarchical regression procedure controlled for the possible influence on MMSE performance of demographic variables (eg, age, duration of dementia symptoms, education, and family history of dementia) before the effect of gender was analyzed. SETTING: Data were gathered by trained neuropsychological examiners from subjects enrolled in the Alzheimer's Disease Research Center at the University of Southern California, Los Angeles. SUBJECTS: One hundred forty-two subjects who met strict criteria for probable AD and 121 nondemented elderly subjects were included in the study. All subjects underwent periodic neuropsychological testing. We extracted MMSE scores and demographic data to test the hypothesis that women would perform more poorly than men on the MMSE. CRITERION MEASURE: The MMSE was chosen because of its wide use in clinical and research settings to screen for the presence or severity of dementia. RESULTS: After controlling for the demographic variables for subjects with AD, we observed a significant difference in the predicted direction for total MMSE score, but there was no significant gender effect on the MMSE for the nondemented elderly sample. Among subjects with AD, gender-associated differences were limited to only a subset of MMSE items. CONCLUSIONS: Results imply that MMSE performance may differ between men and women with AD and that differences might pertain only to discrete areas of cognitive functioning. Although gender effects were relatively small, findings indicate the relevance of gender to studies of AD.
Aged↗
Combined segregation and linkage analysis of late-onset Alzheimer's disease in Duke families using Gibbs sampling.
We illustrate the use of Gibbs sampling for combined segregation and linkage analysis using late-onset families in the Duke Alzheimer's disease (AD) data set. The disease penetrance model is flexible, incorporating variable age of disease onset, sporadic cases, and unknown or uncertain ages of AD onset. Model parameters (including allele frequencies) and lod scores are estimated, and a correction for ascertainment is made. Little indication of linkage was observed for any chromosome 19 or 21 marker. However, there was strong evidence for the existence of an AD major gene under an autosomal dominant/sporadic model.
Aged↗
Risk factors and mortality among black, Caucasian, and Latina women with acute myocardial infarction.
The purpose of this study was to examine the clinical outcome of acute myocardial infarction among women of three ethnic/racial groups and to determine whether observed differences in outcome are explained by differences in associated risk factors. Nine hundred seventeen (917) consecutive admissions occurred among 810 women, of whom 347 (42.8%) were Caucasian, 258 (31.9%) were black, and 205 (25.3%) were Latina. The overall mortality rate was 13%; the Caucasian rate was significantly higher than the Latina rate (16.9% vs 7%, p < 0.01), as was the black rate (13.8% vs 7%, p < 0.05). Comparing survivors with nonsurvivors among the three groups, hypertension was more common for survivors among blacks, as was a history of angina; in-hospital congestive failure was associated with a higher mortality for blacks and Caucasians, as was in-hospital angina for Caucasians. Univariate and multivariate logistic regression for the outcome variables of congestive failure, in-hospital angina, and mortality, showed race to be a significant factor in the lower mortality rate for Latinas in the univariate analysis. In the multivariate analysis, only in-hospital angina and congestive failure significantly influenced mortality. In this study of myocardial infarction among women of lower socioeconomic status, factors other than race were the primary influences on outcome.
Aged↗
Psychosocial functioning and subjective experience in schizophrenia.
This study examines the relationship between psychosocial functioning and subjective experience in 193 individuals diagnosed with schizophrenia or schizoaffective disorder according to Research Diagnostic Criteria. Psychosocial functioning was measured as work functioning, social functioning, living situation, symptomatology, and intrapsychic aspects of the deficit syndrome. Subjective experience consisted of measures of self-esteem, satisfaction with life, and subjective distress. Multivariate analyses resulted in two major findings. The first finding is a model of psychosocial functioning that consists of two factors: disorder-related variables (symptomatology and intrapsychic deficits) and functional status variables (work, social, and living situation). The second major finding is a two-tiered model of the relationship between psychosocial functioning and subjective experience. The model suggests a primary and pervasive relationship between the disorder-related variables and subjective experience and a secondary and less pronounced relationship between functional status variables and subjective experience. The implications of these findings for treatment and rehabilitation and for the study of subjective experience in schizophrenia are discussed.
Activities of Daily Living↗
The Lehigh Valley Recurrent Stroke Study: description of design and methods.
A community-based, prospective study was carried out in the Lehigh Valley to determine how 5 selected risk factors and their control affected the frequency of stroke recurrence and death after an initial stroke. The initial stroke was verified clinically and by computerized tomography. Between 1987 and 1989, 662 patients with an initial stroke were enrolled and followed regularly every 4-6 months for up to 7 visits. The average follow-up period was 2 years. The risk factors selected included hypertension, myocardial infarction, cardiac arrhythmia, diabetes mellitus and transient ischemic attacks. Interim death and its cause were noted. Surviving patients were interviewed and examined to determine whether a second stroke has occurred. At enrollment, 51.4% of the cohort was male. The average age of men was 69.6, while women were older, averaging 74.3 years. Stroke types were thrombosis, 14%; embolus, 23%; lacune, 9%; nonspecific infarct, 48%, and intracerebral hemorrhage, 6%. There were 138 deaths (21%) and 81 second strokes (12%) during follow-up. The frequency of risk factors at enrollment was as follows; hypertension, 59%; myocardial infarction, 25%, cardiac arrhythmia, 47% (of which 16% had atrial fibrillation); diabetes mellitus, 29%, and transient ischemic attack, 18%. Of course many patients had multiple risk factors. We analyzed whether the presence of a risk factor at enrollment and its quality of control during follow-up affected stroke recurrence frequency and the mortality rates. These results will be reported in future papers.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Metropolis sampling in pedigree analysis.
This paper reviews and develops the applications of Markov chain Monte Carlo methods in pedigree analysis, with particular stress on the Metropolis algorithm. In likelihood based genetic analyses, standard deterministic algorithms often fail because of the computational complexity of the observed pedigree data under a proposed genetic model. The new Monte Carlo methods permit approximate maximum likelihood estimation in the presence of such complexity. Monte Carlo implementation of the EM algorithm is the key to successful maximum likelihood analysis. Gibbs sampling and the Metropolis algorithm are alternative ways of defining Markov chains for performing the E step of the EM algorithm. Two applications illustrate the power and simplicity of the Metropolis algorithm. One of these applications involves a discrete model for variance component analysis of quantitative traits; the other application involves a Monte Carlo version of location scores for multipoint linkage analysis.
Algorithms↗
Rose Questionnaire responses among black, Latino, and white subjects in two socioeconomic strata.
We administered the Rose Questionnaire to 1442 black, white, and Latino patients (approximately equal numbers) who sought care for acute chest pain at two medical centers. Of these, 718 subjects were enrolled at a large public hospital serving a low-socioeconomic status population and 724 at a large health maintenance organization hospital serving a middle-class clientele. Using the standard definition of Rose angina, multivariate logistic regression analysis identified five factors that contributed to the relative risk of a positive response: family history of myocardial infarction (2.48), history of peripheral vascular disease (1.41), history of high blood pressure (1.29), history of high cholesterol (1.26), and low-socioeconomic status hospital (0.78). Inquiring about shortness of breath as a substitute for chest pain or an alternative complaint in set one of the Rose Questionnaire did not increase the number of positive responses or differentiate between the socioeconomic groups or race-ethnic subgroups. Having a prior history of self-reported risk factors clearly defined a group with greater likelihood of a positive response to the Rose Questionnaire. Receiving care at a large public hospital (ie, being in a low-socioeconomic status group) was associated with reduced likelihood of having "typical" angina in comparison to receiving care at a health maintenance organization (middle socioeconomic status) for white subjects but not for Latinos and blacks.
Black or African American↗
Chest pain admissions: characteristics of black, Latino, and white patients in low- and mid-socioeconomic strata.
To assess the potential impact of socioeconomic status (SES) factors on health-care seeking behavior for suspected acute coronary artery disease symptoms, equal numbers of black, Latino, and white patients seeking care for chest pain at two large hospital emergency rooms were studied. Differences between low and middle SES groups with respect to pre-attack health, health history, ethnicity, gender, and modes of transportation to the hospital were explored. Highly significant self-reported differences between low SES and middle SES patients were found as follows: low SES subjects were more likely to describe themselves as being in fair to poor general health (68% versus 18%), had more frequent chest pain, reported other types of heart disease, were more often current smokers, more likely to be black or Latino, and to be younger. Members of the low SES group also were less [corrected] likely to have known cholesterol levels, to have used estrogen, to have had a prior ECG or cardiac surgery, to be nonsmokers, to have had a stress test, and to have typical angina. Middle SES subjects more often described typical angina, prior use of estrogen (females), congenital, rheumatic, or family history of heart disease, prior knowledge of high cholesterol, were more likely to be of the male gender, and to be older than the low SES cohort. The data reveal that low SES subjects, with markedly less health-care resources compared with middle SES subjects, have a worse general health and cardiac risk profile despite the fact that they were significantly younger (mean age 53.4 versus 60.7, P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)
Black or African American↗
Neuropathologic diagnosis of Alzheimer disease: interrater reliability in the assessment of senile plaques and neurofibrillary tangles.
A diagnosis of definite Alzheimer disease (AD) is made when there is a history of progressive dementia combined with the pathologic findings of numerous senile plaques and neurofibrillary tangles in neocortex. Recent studies have shown, however, that there may be significant interrater variability in the quantitation of these histopathologic lesions. In the present two-center study, interrater reliability and test-retest reliability for plaque and tangle counts were examined when histologic staining and sampling were controlled. We report similar levels of reliability for plaque and tangle counts in 35 cases of AD, nine normal elderly controls and six non-AD dementias: Pearson correlations for interrater reliability ranged from 0.68 to 0.88, and from 0.97 to 0.99 for test-retest reliability. Using quantitative cut-points, concordance between laboratories for experimental diagnoses of AD versus non-AD made on the basis of these lesion counts ranged from 84 to 92% (kappa scores: 0.69-0.84). The agreement between these experimental diagnoses and the clinicopathologic diagnoses of record ranged from 74 to 86% (kappa scores: 0.50-0.71). Thus, under optimal conditions, a moderate to substantial degree of interrater reliability can be attained in the pathologic diagnosis of AD.
Aged↗
Divergent effects of cytokines on human leukocyte antigen-DR antigen expression of neoplastic and non-neoplastic human thyroid cells.
Apparently complex modulatory effects of alpha-interferon (alpha-IFN), tumor necrosis factor (TNF), and epidermal growth factor (EGF) have been found in neoplastic human thyroid cells, which could possibly affect the final outcome in neoplastic disease. This was achieved by examining the influence of alpha-IFN, TNF, and EGF alone and in combination, on human leukocyte antigen-DR (DR) antigen expression and viability of neoplastic and non-neoplastic human thyroid cells in culture. alpha-IFN-induced DR antigen expression on non-neoplastic human thyroid cells, whereas TNF-alpha or EGF alone were ineffective. The addition of the same TNF-alpha concentrations (10 to 100 ng/ml) to alpha-IFN enhanced the expression of DR antigens compared with the effect of alpha-IFN alone. However, EGF inhibited alpha-IFN-induced DR on the same cells and at the same concentrations (10 to 500 ng/ml) at which the growth factor alone was ineffective. In contrast to the common pattern of cytokine effects on DR expression of all nonmalignant thyroid cell lines, neoplastic thyroid cell lines showed divergent responses to alpha-IFN, TNF-alpha, and EGF. In three malignant thyroid cell lines that were DR negative (follicular carcinoma WRO 82-1 and NRO 87-1 cell lines, and anaplastic carcinoma ARO 81-1), DR antigen could be induced by alpha-IFN and enhanced by TNF-alpha, whereas EGF was ineffective. In a fourth cell line (an anaplastic carcinoma SW1736) alpha-IFN, TNF-alpha, and EGF alone were capable of inducing DR, and a combination of either TNF-alpha and EGF with alpha-IFN potentiated DR induction. In a fifth neoplastic cell line (papillary carcinoma, NPA) that constitutively expressed surface DR, its expression was inhibited by both alpha-IFN and TNF-alpha and was not affected by EGF.
Antibodies↗
Childhood brain tumors that occupy more than one compartment at presentation. Multiple compartment tumors.
Children whose brain tumor involves two or more compartments at presentation differ clinically and pathologically from children whose brain tumor is confined to one compartment. In this study of 3,291 children with a brain tumor, at least 10% had a tumor that occupied two or three compartments at first hospitalization. Infratentorial tumors occupying multiple compartments were 1.7 times more likely to involve the cervicomedullary junction than the mesodiencephalic junction. Younger children (1-3 years) were more likely to have had multiple compartment tumors than older children. Children whose tumor was limited to the infratentorial compartment had a longer survival than children whose tumor also occupied other compartments. Ependymoma, anaplastic ependymoma, and astrocytoma (nos) were over represented among infratentorial multiple compartment tumors. Pilocytic astrocytoma, primitive neuroectodermal tumor (medulloblastoma), and desmoplastic medulloblastoma were less likely to have occupied multiple compartments at the time of the first surgical exploration. The distributions of histologic features in tumors at the cervicomedullary junction differed from those in tumors limited to the posterior fossa or to the spinal canal. Seizures were more likely if the tumor was confined to the supratentorial compartment, whereas nausea or vomiting and headache were more likely if the tumor was confined to the infratentorial compartment. Children whose tumor was confined to the spinal canal were significantly more likely to have bladder symptoms and back and/or abdominal pain than those whose tumor also involved compartments above the foramen magnum. We conclude that brain tumors apparently confined to one compartment at presentation are biologically and structurally different from tumors evident in two or more compartments.
Adolescent↗