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Biomedical subjects

J Sims

Publications and source records attributed to J Sims.

At least 19 recordsLinked to original sources
PubMed1992

Establishing the limits of the Mini-Mental State. Examination of 'subtests'.

It has been suggested that the Mini-Mental State examination can be used to examine a patient's cognitive profile. We therefore examined the validity of Mini-Mental State subtests and individual items. The memory item, attention-concentration items, and constructional item had satisfactory sensitivity-specificity and correlated significantly with scores on neuropsychological tests. In contrast, four of the five Mini-Mental State language items had very low sensitivity, and three of five failed to correlate with neuropsychological test scores. These findings establish limits with regard to the ability of the Mini-Mental State to generate a cognitive profile. Our data also provide information regarding validity, difficulty level, and optimal cutoff scores for widely used mental status tasks.

Adult↗
PubMed1992

Neurobehavioral effects of long-term occupational exposure to organic solvents: two comparable studies.

Two comparable cross-sectional studies were carried out employing the same methodology but involving two separate solvent-exposed populations (N = 90, N = 144). In each study, solvent-exposed workers were compared with age-matched controls on tests selected from the Neurobehavioral Evaluation System and on standardized questionnaire measures of symptomatology and psychiatric state. A similar pattern of results was obtained in the two studies indicating a significant effect on cognitive functioning, after controlling for confounding variables, occurring in those with more than 30 years of exposure. A more specific effect on learning processes was observed in those with more than 10 years of exposure. There were no indications in either study of a solvent-related increase in psychiatric symptoms.

Adult↗
PubMed1992

Welcan units.

Explore the source record for details and available documents.

Cell Biology↗
PubMed1991

Genetics of Type A behavior in two European countries: evidence for sibling interaction.

Young male twins in The Netherlands and England completed the Jenkins Activity Survey (Dutch and English versions, respectively), a measure of Type A behavior. Separate model fitting analysis revealed a similar pattern of variance estimates and associated goodness of fit across the two countries. The data were then analyzed concurrently, with a scalar parameter included to account for differences in variance due to the disparity of the measurement scales. A model including additive genetic and individual environmental effects gave a good explanation to the data. The heritability estimate was 0.28. Models of social interaction and dominance explained the data even better, the former being preferred. The twins' parents were included in the analysis to examine population variation for Type A behavior intergenerationally. There was evidence for individual environmental experiences having a greater influence on Type A behavior in the older generation.

Adolescent↗
PubMed1991

A twin study approach towards understanding genetic contributions to body size and metabolic rate.

The genetic and environmental determinants of a brief assessment of metabolic rate at rest and under psychological stress were studied in 40 pairs of monozygotic and 40 pairs of dizygotic young adult male twins. Height, weight and age were employed as covariates. Univariate analyses showed a high heritability for height and weight and moderate heritability for metabolic rate. Classical twin analyses and multivariate genetic modeling indicated that genetic influences on resting metabolic rate were entirely explained by body weight: there was no independent genetic contribution to resting metabolic rate. Metabolic rate under psychological stress, on the other hand, showed a significant genetic effect. The exponent (3/4) in the power function relating body weight to resting metabolic rate was the same as that found in a wide variety of animal species, a value that has been proposed as defining a body weight set point. We speculate that an adult body weight set point is genetically transmitted. Independent genetic effects on resting metabolic rate would be observed only when the normal equilibrium between body weight and metabolic rate is unbalanced during development, aging or disease. The study illustrates the use of multivariate genetic analyses of twin data which may be readily applied to widely used metabolic rate assessments.

Adolescent↗
PubMed1990

Cardiovascular and metabolic activity at rest and during psychological and physical challenge in normotensives and subjects with mildly elevated blood pressure.

Heart rate, systolic and diastolic blood pressure, and respiratory and metabolic activity were recorded prior to and during mental arithmetic and a video game task in 20 young men with mildly elevated casual systolic blood pressures. Twenty-five unambiguously normotensive young men were tested under the same protocol. For pretask baseline physiological activity, group differences emerged for all cardiovascular and metabolic variables; thus the elevated blood pressure group displayed not only higher resting cardiovascular levels than normotensive subjects, but higher levels of metabolic activity too. With regard to change in physiological activity from rest to task, the group with mildly elevated blood pressure showed reliably larger increases in heart rate to the mental arithmetic task than the normotensive subjects. These effects, however, were not paralleled by group differences in metabolic activity increase. Physiological measures were also taken prior to and during graded dynamic exercise. The subsequent calculation of individual heart rate-oxygen consumption exercise regression lines allowed the comparison of actual and predicted heart rates during psychological challenge. The subjects with mildly elevated blood pressure displayed significantly greater discrepancies between actual and predicted heart rate values than normotensives during the psychological tasks in general and mental arithmetic in particular. Group differences in physiological activity during exercise largely reflected the pattern seen at rest. A possible exception here was systolic blood pressure. Not only were systolic blood pressure levels higher throughout the exercise phase for mildly elevated blood pressure subjects, but this group evidenced more of an increase from rest to exercise than the normotensives.

Adult↗
PubMed1989

Recombinant interleukin 7, pre-B cell growth factor, has costimulatory activity on purified mature T cells.

The activation of highly purified murine peripheral T cells in vitro by Con A is dependent on a co-stimulatory signal that is not IL-1 or IL-2. Previous evidence has demonstrated that the recently defined lymphokine IL-6 could provide costimulatory activity for purified T cells cultured with Con A. In this report we demonstrate that IL-7 also has potent co-stimulatory activity for purified murine T cells, as well as its previously described ability to support the growth of pre-B cells in Witte-Whitlock cultures. When rIL-7 was added to cultures of purified T cells together with Con A, it induced the expression of IL-2 receptors, IL-2 production, and consequently proliferation. In addition, IL-7 exhibited the same magnitude of activity in this assay as IL-6. Also, anti-IL-6 antibody which inhibited the IL-6-induced response had no effect on the IL-7 response. Thus, IL-7 does not act by inducing IL-6. These results demonstrate that IL-7, a potent growth stimulus for pre-B cells, also has a role in T cell activation.

Animals↗
PubMed1989

AIDS: the HIV epidemic. A time of transition.

The surveillance of clinical cases of acquired immune deficiency syndrome (AIDS) in the United States began in June 1981 when the first case was reported. Since then, state and federal public health officials have continuously monitored progression of the epidemic by the number of persons reported with diagnosed clinical AIDS. The human immunodeficiency virus (HIV) that causes AIDS was identified in 1983 and an antibody test was licensed by the Food and Drug Administration in 1985. Recent studies have shown that the time from HIV infection to development of clinical AIDS is an average of seven or more years. Consequently, the reported cases of clinical AIDS reflect the severity of the epidemic an average of seven years ago or more, not now, and certainly not in the future. The AIDS epidemic is in reality an HIV epidemic. The number of persons with HIV infections is a better measure of the present status and future course of the disease. This paper discusses the development of HIV prevalence and incidence studies and illustrates the use of these data to predict the future number of persons with clinical AIDS and the economic impact of the epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed1987

A comparative evaluation of heart rate reactivity during MATH and a standard mental arithmetic task.

Heart rate was monitored while 20 young males completed MATH, a computer-operated mental arithmetic task specifically designed for use in experiments involving subjects of heterogeneous numerical ability, and a standard mental arithmetic task used in this laboratory on several occasions. Both tasks elicited sizeable increases in heart rate, and comparison of subjects' reactivity scores revealed significant inter-task consistency of reaction.

Adult↗
PubMed1987

A family study of developmental effects upon blood pressure variation.

In an earlier study of blood pressure variation in middle aged parents and their young adult twin offspring, the greater blood pressure variation observed in the parent sample was accounted for in terms of an increasing influence of individual environmental experiences with increasing age and a commensurate reduction in the impact of heredity. In the present study, the sample size was enlarged to provide a more powerful test of these effects. Maximum likelihood model-fitting techniques were applied to blood pressure covariation in balanced pedigrees, consisting of 85 families (40 MZ and 45 DZ twin pairs). As before, our analysis indicated that a developmental effect was a salient factor in the older age group.

Adult↗
PubMed1987

A developmental hypothesis for adult blood pressure.

Observed increases in phenotypic variance for blood pressure during adulthood are a predictable consequence of an a priori model for developmental change and continuity previously applied to cognitive development. The implications of this model for genetic and environmental covariances depend on the mechanism which maintains developmental continuity. Using data from young adult twins and their parents, it is shown how traditionally estimated genetic and environmental parameters may be reinterpreted in the light of the developmental model. Illustrative data suggest a hypothesis that genetic effects on blood pressure are largely temporally pleiotropic, acting consistently but not cumulatively throughout adulthood, while environmental influences act haphazardly but their effects are transmitted forward with high fidelity.

Adolescent↗
PubMed1986

Temporal and inter-task consistency of heart rate reactivity during active psychological challenge: a twin study.

Heart rate was monitored while 22 pairs of young male monozygotic and 29 pairs of young male dizygotic twins were exposed to a video game and a mental arithmetic task. The heart rate reactions of the monozygotic twins showed much greater concordance than those of the dizygotic twins. Analysis of the data for the 102 individuals demonstrated reliable inter-task consistency of heart rate reaction. In addition, comparison of the heart rate reactions of ten pairs of monozygotic and ten pairs of dizygotic twins who had been tested more than a year earlier and their present reactivities revealed impressive temporal consistency.

Adolescent↗
PubMed1986

Graded mental arithmetic as an active psychological challenge.

A computer-operated mental arithmetic task is outlined which presents questions at a level of difficulty continuously determined by subjects' accuracy of response on the previous question. The programme incorporates 5 levels of difficulty, and all questions concern the addition or subtraction of two numbers which vary in digit-span according to the current level of difficulty. Response requirements are manual rather than verbal so that, in addition to monitoring heart rate, subjects' exhaled air may be collected throughout the task in order to determine oxygen consumption.

Computers↗
PubMed1986

Familial and individual influences on blood pressure.

Although familial aggregation of blood pressure is well documented, few studies have considered the changing contribution of genetic and environmental influences during adulthood. Applying maximum likelihood model fitting to blood pressure covariation in balanced pedigrees including both parents and their young adult twin offsprings (25 MZ, 32 DZ, aged between 16 and 24 years), it is shown that the increased variation in parents is explained by such developmental changes. For DBP, an apparent reduction in heritability from 68% to 38% from young adulthood to middle age results from the increasing impact of individual environmental experience (E1), with little or no influence from shared family environmental (E2). For SBP, shared environmental effects may play a part. Given the relatively small size of the present sample, the conclusions are to be seen as tentative. An augmented family study, incorporating middle aged twins and their young adult offspring, will clarify the causation of these developmental changes.

Adolescent↗
PubMed1985

Comparison of health problems related to work and environmental measurements in two office buildings with different ventilation systems.

A cross sectional survey investigating "building sickness" was carried out in two buildings with similar populations of office workers but differing ventilation systems, one being fully air conditioned with humidification and the other naturally ventilated. The prevalence of symptoms related to work was assessed by a questionnaire administered by a doctor. A stratified, randomly selected sample of workers was seen (84% response). Building sickness includes several distinct syndromes related to work, most of which were significantly more common in the air conditioned building than the naturally ventilated building--namely, rhinitis (28% v 5%), nasal blockage and dry throat (35% v 9%), lethargy (36% v 13%), and headache (31% v 15%). The prevalence of work related asthma and humidifier fever was low and did not differ significantly between the two buildings. An environmental assessment of the offices was performed to attempt to identify possible factors responsible for the differences in the prevalence of disease. Globe temperature, dry bulb temperature, relative humidity, moisture content, air velocity, positive and negative ions, and carbon monoxide, ozone, and formaldehyde concentrations were all measured. None of these factors differed between the buildings, suggesting that building sickness is caused by other factors.

Air Conditioning↗
PubMed1985

A twin study of cardiac reactivity and its relationship to parental blood pressure.

The cardiac reactivity of 40 monozygotic and 40 dizygotic pairs of young male twins was monitored during psychological challenge, as afforded by a video game. The observed pattern of variation could not be accounted for solely by environmental factors. In fact, a simple genetic model that implicated additive genetic effects, along with those stemming from individual environments, best fitted the data. In addition, cardiac reactions were substantially greater for subjects whose parents both had relatively elevated blood pressure. Overall, these data suggest individual differences in cardiac reactivity have a heritable component, and that high reactivity may be a precursor of elevated blood pressure.

Adolescent↗