Douglas C. Ewbank

Alpha-synuclein cortical Lewy bodies correlate with dementia in Parkinson’s disease

Background: Dementia is a frequent complication of idiopathic parkinsonism or PD, usually occurring later in the protracted course of the illness. The primary site of neuropathologic change in PD is the substantia nigra, but the neuropathologic and molecular basis of dementia in PD is less clear. Although Alzheimer’s pathology has been a frequent finding, recent advances in immunostaining of α-synuclein have suggested the possible importance of cortical Lewy bodies (CLBs) in the brains of demented patients with PD. Methods: The brains of 22 demented and 20 nondemented patients with a clinical and neuropathologic diagnosis of PD were evaluated with standard neuropathologic techniques. In addition, CLBs and dystrophic neurites were identified immunohistochemically with antibodies specific for α-synuclein and ubiquitin; plaques and tangles were identified by staining with thioflavine S. Associations between dementia status and pathologic markers were tested with logistic regression. Results: CLBs positive for α-synuclein are highly sensitive (91%) and specific (90%) neuropathologic markers of dementia in PD and slightly more sensitive than ubiquitin-positive CLBs. They are better indicators of dementia than neurofibrillary tangles, amyloid plaques, or dystrophic neurites. Conclusion: CLBs detected by α-synuclein antibodies in patients with PD are a more sensitive and specific correlate of dementia than the presence of Alzheimer’s pathology, which was present in a minority of the cases in this series.

Reproduction and social organization in sub-Saharan Africa

Unlike most Asian and Latin American countries, sub-Saharan Africa has seen both an increase in population growth rates and a weakening of traditional patterns of child-spacing since the 1960s. It is tempting to conclude that sub-Saharan countries have simply not reached adequate levels of income, education, and urbanization for a fertility decline to occur. This book argues, however, that such a socioeconomic threshold hypothesis will not provide an adequate basis for comparison. These authors take the view that any reproductive regime is also anchored to a broader pattern of social organization, including the prevailing modes of production, rules of exchange, patterns of religious systems, kinship structure, division of labor, and gender roles. They link the characteristic features of the African reproductive regime with regard to nuptiality, polygyny, breastfeeding, postpartum abstinence, sterility, and child-fostering to other specifically African characteristics of social organization and culture. Substantial attention is paid to the heterogeneity that prevails among sub-Saharan societies and considerable use is made, therefore, of interethnic comparisons. As a result the book goes considerably beyond mere demographic description and builds bridges between demography and anthropology or sociology.

Performance of the dementia severity rating scale: a caregiver questionnaire for rating severity in Alzheimer disease.

Summary:The Dementia Severity Rating Scale (DSRS) is an informant-based, multiple- choice questionnaire that assesses severity from the mildest to the most severe stages in the major functional and cognitive domains affected in Alzheimer disease (AD). The DSRS has good reliability as measured by making repeated observations over short time periods and by comparing caregiver responses to information collected by a physician or an experienced nonphysician research associate. The measure correlates favorably with the Washington University Clinical Dementia Rating scale and with standard cognitive testing measures. The DSRS provides a simple, valid, and sensitive measure of impairment associated with AD. It is ideally suited for multisite collaborative studies and can be implemented with a minimum of staff time and training.

The effect of child fostering on feeding practices and access to health services in rural Sierra Leone.

In Sierra Leone, where infant and child mortality rates are quite high, a large proportion of small children from 1 to 5 yr are fostered: living away from their mothers. This paper examines the relationships between fosterage and child feeding practices and childrens access to Western medical care. Ethnographic data from field studies in Sierra Leone are combined with quantitative data from Serabu Hospital, which show that fostered children are underrepresented in hospital admissions and that young fosters present more problems of malnutrition. (Fostered girls appear to be at more risk in both these categories than boys.) Unlike young fosters, however, older ones do not appear to be at more risk than children with mothers. We draw connections between these results and patterns of intra-household discrimination in food allocation and access to medical treatment for young fostered children: especially those sent to elderly rural caretakers. Finally, we examine the implications of the findings for applied issues, arguing that fostered children may slip through the cracks of maternal-child health care programs.

Measuring selection in contemporary human populations

Are humans currently evolving? This question can be answered using data on lifetime reproductive success, multiple traits and genetic variation and covariation in those traits. Such data are available in existing long-term, multigeneration studies — both clinical and epidemiological — but they have not yet been widely used to address contemporary human evolution. Here we review methods to predict evolutionary change and attempts to measure selection and inheritance in humans. We also assemble examples of long-term studies in which additional measurements of evolution could be made. The evidence strongly suggests that we are evolving and that our nature is dynamic, not static.

Natural selection in a contemporary human population

Our aims were to demonstrate that natural selection is operating on contemporary humans, predict future evolutionary change for specific traits with medical significance, and show that for some traits we can make short-term predictions about our future evolution. To do so, we measured the strength of selection, estimated genetic variation and covariation, and predicted the response to selection for women in the Framingham Heart Study, a project of the National Heart, Lung, and Blood Institute and Boston University that began in 1948. We found that natural selection is acting to cause slow, gradual evolutionary change. The descendants of these women are predicted to be on average slightly shorter and stouter, to have lower total cholesterol levels and systolic blood pressure, to have their first child earlier, and to reach menopause later than they would in the absence of evolution. Selection is tending to lengthen the reproductive period at both ends. To better understand and predict such changes, the design of planned large, long-term, multicohort studies should include input from evolutionary biologists.

A reducible four-parameter system of model life tables

Abstract In this paper a four-parameter extension of Brasss relational system of model life tables is suggested that (1) matches a wide range of empirical age patterns of mortality, (2) is easy to apply, especially to partial life tables, and (3) contains demographically meaningful parameters. A test of the model on a set of 62 empirical life tables indicates that four parameters are necessary and sufficient for fitting a wide range of mortality patterns. A further test on an historical series of Swedish life tables reveals a consistent pattern of mortality change. Examination of the parameters for a set of geographicallyrelated life tables suggests a way to define families of life tables. Identification of such temporal and spatial relationships allows the model to be reduced to a form with twoor three-parameters for application to incomplete or inaccurate data.

Reduction of mortality in rural Haiti through a primary-health-care program.

Deaths and their causes in a rural Haitian population of 8820 were studied through hospital records, death registration, a disease survey, and health surveillance. The results were used in selecting eight diseases for the delivery of health services by village-level health workers. The impact of the services was measured by monitoring annual age-specific and disease-specific mortality rates and by comparing them with officially estimated national mortality rates. Mortality rates fell progressively during five years, to levels only one fourth as high as the national estimates. The fall in mortality was associated principally with services that prevented deaths due to tetanus, malnutrition, diarrhea, and tuberculosis. The total program of hospital and village health services saved 495 years of potential life per thousand population per year. Most of the saving was attributable to preventive services. The program eventually served more than 115,000 persons, and it has been replicated by other agencies for an additional 135,000 Haitians.

Deaths attributable to Alzheimer's disease in the United States.

OBJECTIVES This study provided 2 estimates of the number of deaths attributable to Alzheimers disease in the United States. METHODS One estimate was based on data from the East Boston, Mass, study. The second was based on a simulation using population-based estimates of prevalence and separate estimates of excess death by duration of disease. RESULTS Despite different methods and very different estimates of prevalence, these 2 methods led to very similar estimates of 173,000 and 163,000 excess deaths. CONCLUSIONS These estimates suggest that 7.1% of all deaths in the United States in 1995 are attributable to Alzheimers disease, placing it on a par with cerebrovascular diseases as the third leading cause of death.

Quantitative anatomic measures and comorbid medical illness in late-life major depression

The authors examined the individual and relative roles of atrophy, comorbid medical illness, and cerebrovascular risk factors in the pathogenesis of late-life major depressive disorder (MDD). They used magnetic resonance imaging techniques to study 28 subjects with late-life MDD, 29 healthy control subjects, and 34 subjects with probable dementia of the Alzheimer type (DAT). Depressed subjects showed increases in cerebrospinal fluid volumes comparable to the DAT group but significantly different from control subjects. High-intensity signals, but not measures of atrophy correlated significantly with cerebrovascular risk factor scores. A logistic regression revealed that both brain atrophy and medical illness are associated with an increased risk of developing MDD. Data suggest that both atrophy and comorbid medical illness increase the likelihood of developing MDD in late life.