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Biomedical subjects

M E Farmer

Publications and source records attributed to M E Farmer.

17 recordsLinked to original sources

Education and change in cognitive function. The Epidemiologic Catchment Area Study.

The association between educational attainment and decline in cognitive function over an interval of 1 year was examined for 14,883 subjects 18 years and older in the National Institute of Mental Health Epidemiologic Catchment Area Study. Cognitive function was assessed at both time points by the Mini-Mental State Examination (MMSE); cognitive decline was coded as a dichotomous variable and was defined as 1 if the subject's score had declined 3 or more points from the baseline MMSE score at the 1-year follow-up interview and as 0 otherwise. The association between educational attainment and decline in cognitive function over 1 year was examined in logistic regression models that were stratified by age group (< 65 years, > or = 65 years) and by baseline MMSE level (MMSE > 23, MMSE < or = 23). Covariates included age, baseline MMSE score, ethnicity, residence, lifetime diagnosis of abuse of alcohol or other drugs, and gender. In those with baseline MMSE > 23, education was a significant predictor of cognitive decline, not only in the elderly but also in younger subjects. Among those with baseline MMSE < or = 23, education was not a significant predictor of cognitive decline. The fact that education provides protection against cognitive decline even in those younger than 65 years, in whom the prevalence and incidence of dementia are very low, would seem to indicate that education or its correlates provides protection against processes other than dementia that might produce a decline in test performance in young persons.

Adolescent

Cognitive deficits related to major organ failure: the potential role of neuropsychological testing.

Until recently, little attention has been paid to the possibility of cognitive deficits in patients with disease or failure of major organs such as the liver, kidney, or heart. However, there is a growing awareness that major organ failure often has neuropsychological sequelae. These sequelae may at times be quite subtle and not detectable under gross examination. Nevertheless, even subtle deficits may have a major impact on adherence to medical regimens, psychosocial adjustment, and quality of life of patients. Neuropsychological assessment has a potentially valuable role to play both in research and in clinical work. It can be useful in adding to our knowledge of the cognitive effects of various types, severity and duration of major organ disease, as well as sequelae associated with treatment. It also is a potentially valuable clinical tool for identifying cognitive deficits that will affect the quality of life and probability of survival for organ failure patients.

Cognition Disorders

One-month prevalence of mental disorders in the United States and sociodemographic characteristics: the Epidemiologic Catchment Area study.

The associations between the one-month prevalence rates of mental disorders and sociodemographic characteristics were investigated for 18,571 people interviewed in the first-wave community samples of all 5 sites in the US National Institute of Mental Health (NIMH) Epidemiologic Catchment Area program. Men were found to have a significantly higher rate of cognitive impairment than women after controlling for the effects of age, race or ethnicity, marital status and socioeconomic status. Marital status was one of the most powerful correlates of mental disorder risk: the odds of separated or divorced people having any NIMH Diagnostic Interview Schedule disorder were twice that of married people after controlling for age, gender, race or ethnicity and socioeconomic status. The odds of those in the lowest socioeconomic status group having any Diagnostic Interview Schedule disorder was about 2.5 times that of those in the highest socioeconomic status group, controlling for age, gender, race or ethnicity and marital status. For all disorders except cognitive impairment, race or ethnicity did not remain statistically significant after controlling for age, gender, marital status and socioeconomic status.

Adolescent

Comorbidity of mental disorders with alcohol and other drug abuse. Results from the Epidemiologic Catchment Area (ECA) Study.

The prevalence of comorbid alcohol, other drug, and mental disorders in the US total community and institutional population was determined from 20,291 persons interviewed in the National Institute of Mental Health Epidemiologic Catchment Area Program. Estimated US population lifetime prevalence rates were 22.5% for any non-substance abuse mental disorder, 13.5% for alcohol dependence-abuse, and 6.1% for other drug dependence-abuse. Among those with a mental disorder, the odds ratio of having some addictive disorder was 2.7, with a lifetime prevalence of about 29% (including an overlapping 22% with an alcohol and 15% with another drug disorder). For those with either an alcohol or other drug disorder, the odds of having the other addictive disorder were seven times greater than in the rest of the population. Among those with an alcohol disorder, 37% had a comorbid mental disorder. The highest mental-addictive disorder comorbidity rate was found for those with drug (other than alcohol) disorders, among whom more than half (53%) were found to have a mental disorder with an odds ratio of 4.5. Individuals treated in specialty mental health and addictive disorder clinical settings have significantly higher odds of having comorbid disorders. Among the institutional settings, comorbidity of addictive and severe mental disorders was highest in the prison population, most notably with antisocial personality, schizophrenia, and bipolar disorders.

Adult

Acquired word deafness, and the temporal grain of sound representation in the primary auditory cortex.

This paper explores the nature of the processing disorder which underlies the speech discrimination deficit in the syndrome of acquired word deafness following from pathology to the primary auditory cortex. A critical examination of the evidence on this disorder revealed the following. First, the most profound forms of the condition are expressed not only in an isolation of the cerebral linguistic processor from auditory input, but in a failure of even the perceptual elaboration of the relevant sounds. Second, in agreement with earlier studies, we conclude that the perceptual dimension disturbed in word deafness is a temporal one. We argue, however, that it is not a generalized disorder of auditory temporal processing, but one which is largely restricted to the processing of sounds with temporal content in the milliseconds to tens-of-milliseconds time frame. The perceptual elaboration of sounds with temporal content outside that range, in either direction, may survive the disorder. Third, we present neurophysiological evidence that the primary auditory cortex has a special role in the representation of auditory events in that time frame, but not in the representation of auditory events with temporal grains outside that range.

Animals

Longitudinally measured blood pressure, antihypertensive medication use, and cognitive performance: the Framingham Study.

The relation of longitudinally measured blood pressure to cognitive performance in the absence of clinically diagnosed cerebrovascular disease was investigated in the Framingham Study. In 1976-1978, neuropsychologic testing was administered to 1993 participants aged 55-89 years. Performance on an education-adjusted composite of these tests was examined in relation to measures of chronicity of hypertension as well as the average systolic and average diastolic blood pressure. All analyses were stratified by antihypertensive medication use during the 2 years prior to cognitive testing and adjusted for age, sex, occupation, alcohol consumption, and participation rate in prior examination cycles. Among subjects on drug therapy for hypertension, there was no association between cognitive performance and longitudinally measured blood pressure. The proportion of cycles in which hypertension was present and average systolic and diastolic blood pressure had a significant inverse relation with cognitive performance only in the group not on antihypertensive drug therapy. However, among subjects on antihypertensive medication at earlier cycles, there was a highly significant graded relation between cognitive impairment and the probability of being off medication at the time of testing. These results suggest that hypertension-related subclinical vascular disease is not an important cause of cognitive impairment in the elderly. Cognitive impairment may, however, be associated with a reduced adherence to drug treatment regimens.

Aged

Anthropometric indicators and hip fracture. The NHANES I epidemiologic follow-up study.

A cohort of 3,595 white women aged 40-77 years was followed for an average of 10 years during which 84 new cases of hip fracture were identified. Triceps skinfold thickness and arm muscle area measured at baseline were examined as possible risk factors for hip fracture controlling for physical activity, height, menopausal status, calcium consumption, and smoking. Of these variables only arm muscle area, triceps skinfold thickness, and activity in recreation were independent predictors of hip fracture incidence using the Cox proportional hazards model. After adjustment, the estimated relative risk of hip fracture was approximately two for an increment of each anthropometric indicator (adjusted for the other) equivalent to comparing those at the 25th percentile to those at the 75th percentile (maximum width of 95% confidence intervals, 1.2-2.9). Risk of hip fracture was approximately two-fold for persons who reported little recreational exercise compared to persons who reported much recreational exercise (95% confidence interval, 1.2-3.2). Our findings are the first evidence from a prospective study that anthropometric indicators besides body mass index may have an independent relationship to risk of hip fracture.

Adult

Physical activity and depressive symptoms: the NHANES I Epidemiologic Follow-up Study.

The relation between self-reported physical activity and depressive symptoms was analyzed for 1,900 healthy subjects aged 25-77 years in the Epidemiologic Follow-up Study (1982-1984) to the first National Health and Nutrition Examination Survey (NHANES I). Depressive symptomatology as measured by the Center for Epidemiologic Studies Depression Scale (CES-D) was examined by sex and race in relation to recreational physical activity and physical activity apart from recreation, controlling for age, education, income, employment status, and chronic conditions. Little or no recreational physical activity and little or no physical activity apart from recreation were cross-sectionally associated with depressive symptoms in whites and in blacks. After exclusion of those with depressive symptoms at baseline, recreational physical activity was an independent predictor of depressive symptoms an average of eight years later in white women. The adjusted odds of depressive symptoms at follow-up were approximately 2 for women with little or no recreational physical activity compared with women with much or moderate recreational physical activity (95% confidence interval 1.1-3.2). These findings are the first indication from a prospective study of a large community sample that physical inactivity may be a risk factor for depressive symptoms.

Adult

Blood pressure and cognitive performance. The Framingham Study.

In 1976-1978, a battery of eight neuropsychologic tests were administered to 2,123 participants in the Framingham Study who were aged 55-89 years. Performance on each test was examined in relation to concurrently measured systolic and diastolic blood pressure while controlling for age, sex, education, antihypertensive medication, alcohol consumption, and smoking. Those with a diagnosis of stroke were excluded from the analysis. In the remaining sample of 2,032, neither blood pressure nor antihypertensive treatment was significantly associated with cognitive performance. Even after excluding persons on antihypertensive medication, blood pressure was still unrelated to cognitive performance. In contrast to other studies, the authors found no consistent relation between blood pressure and cognitive performance.

Aged

Methodological issues in screening for dementia: the problem of education adjustment.

The methodological problems of developing efficient and unbiased screening methods for population-based studies of dementia have received scant attention. The potential advantages of education-adjusted screening methods are discussed. The implications for adjustment techniques of a negative correlation of educational attainment with age are emphasized. Two education adjustment methods, a stratified regression method and a nonparametric method, which take the age-education correlation into account are described, compared, and illustrated.

Age Factors

Ultrastructural comparison of ion beam and radiofrequency plasma etching effects on biological tissue sections.

Three dry etching techniques (Ar+ ion beam, O2+ ion beam, O2 radiofrequency electrodeless discharge) were compared with respect to preferential etching and damage to the ultrastructure of glutaraldehyde-fixed Epon-embedded frog skeletal muscle sections. SEM and TEM studies were performed on both unstained and stained (osmium tetroxide, uranyl acetate) sections. Etching effects were observed to differ for the various ion beam or plasma etching techniques. Whereas selective retention of electron dense structures (e.g. Z lines, nuclear heterochromatin) was observed for oxygen plasma etching, preferential etching of these components was observed using O2+ ion beam bombardment. Selectively etched Z lines and etch-resistant nucleoli were observed for both reactive (O2+) and inert (Ar+) ion beam sputtering after sufficiently high ion doses. The above suggest that selective etching under keV ion beam irradiation is related more to physical sputtering processes (momentum transfer) than to the chemical reactivity of the incident ion. Heavy metal post-fixation and staining had no qualitative effect on the nature of the selective etching phenomena. The above findings are significant in that they potentially influence both electron and ion microprobe measurements of etched biological specimens.

Animals

Race and sex differences in hip fracture incidence.

Incidence rates for hip fracture in the United States were estimated using non-federal hospital discharges from the National Hospital Discharge Survey for the years 1974-1979. Age-specific incidence curves for women and for men showed similar patterns of increase in risk with age, with risks approximately doubling every five years after age 50. Age-specific rates by five-year age groups were compared among the four race-sex groups. No significant differences were observed between Black females, Black males, and White males. In contrast, rates for White females were one and one-half to four times those for Black females after age 40 and were approximately double those for White males after age 50. Analysis based on an independent data source of non-federal hospital discharges in Washington, DC confirmed these relationships. In the Washington study, White women were at twice the risk for hip fracture (controlled for age) compared with Black women and at 2.7 times the risk for hip fracture (controlled for age) compared to White men. No significant differences were observed between Black women and Black men.

Adult

Absence of menopausal effect on hip fracture occurrence in white females.

The rate of hip fracture among White females rises sharply between ages 40 and 44 and then continues at a constant rate of acceleration doubling every five to six years throughout life with no deviation during, or in the years immediately following, menopause. We suggest that the important role of sex hormones and other factors in osteoporosis commences prior to menopause. A premenopause prevention strategy which postpones the onset of the osteoporotic process by five or six years would be expected to reduce the risk of hip fracture by 50 per cent throughout the remainder of a woman's life.

Adult

Ion beam etching effects in biological microanalysis.

Oxygen ion beam sputter etching used in SIMS has been shown to produce morphologic effects which have similarities and differences in comparison to rf plasma etching of biological specimens. For example, selective retention of nuclear and plasma membranes is observed in both cases, however, heterochromatin is preferentially sputtered by O2+ bombardment in SIMS and preferentially preserved during O2 plasma etching. Sputter yield variations resulting from structural microheterogeneity are illustrated (e.g. etch-resistant nucleoli in preferentially etched nuclei), including their impact upon ion image formation in an ion microanalyzer. These image artifacts must be evaluated before secondary ion images revealing subcellular organelles can be related quantitatively to elemental localization in cells or tissues. To minimize gross surface roughness effects such as cone formation induced by ion bombardment, ion imaging studies of thin sections using low primary ion doses are indicated.

Animals