Estimation of body fat from skinfold thicknesses in middle-aged and older men and women: A multiple component approach

The relationship of skinfold thicknesses and body density to body fatness was assessed, and skinfold prediction equations were developed for the estimation of body fatness determined from measures of body density, total body water, and bone mineral in a sample of 91 males and 116 females aged 34–84 years. For a given skinfold thickness, adjustment for individual deviations in the water and bone mineral fractions of the fat-free body assumed constant by traditional body composition models resulted in absolute reductions in overstimates of body fatness from 4.5 to 1.9% in females and from 2.8 to 1.7% in males for every 15 year increase in age. Percentage fat from density, water, and bone was estimated from skinfold thicknesses with SEEs of 2.9% in males and 3.8% in females. When compared to percentage fat from our multicomponent-derived criterion, percentage fat from body density and a two-component model resulted in individual errors ranging from underestimates of 5.6% fat to overestimates of 14.0% fat. The multicomponent prediction equations presented herein should produce more valid estimates of body composition in middle-aged and older men and women than equations based on two-component models. © 1992 Wiley-Liss, Inc.     

The genetic architecture of hyponeophagia and the action of diazepam in rats

Rats of 18 genotypes derived from the Roman selected strains were tested for inhibition of feeding due to novelty (hyponeophagia) in the absence or presence of 1 mg/kg diazepam. The resulting data from three behavioral indices were subjected to the Hayman [(1954). Biometrics10:235–244], variance/covariance, Mendelian cross, and single-test cross analyses. Additive genetic variation, directional dominance for high neophobia, and some nonallelic interaction were detected. The genetic architecture of the separate behavioral indices, and its modification in the drugged subjects, was discussed in relation to evolutionary adaptation and the anxiolytic and appetite-enhancing actions of the drug.This work was jointly funded by the Science and Engineering Research Council and Imperial Chemical Industries Pharmaceuticals Ltd. through an award to R.A.S.     

Who Will Benefit? Using Radiomics to Predict Response to Oxaliplatin-Based Chemotherapy in Patients with Colorectal Liver Metastases

Annals of Surgical Oncology -     

The Genetics of Obesity: What Have Genetic Studies Told Us About the Environment

Genetic studies have shown that both childhood and adult body mass index are substantially heritable. The evidence for shared family environmental influences is largely absent, even though there are clear indications that secular changes in energy expenditure have brought about a significant increase in the prevalence of obesity. This apparent inconsistency may be explained by the dual phenomena of the near-universality of access to environments that facilitate reductions in energy expenditure (e.g., TV as a recreational pastime), together with heritable individual differences in the response to or utilization of these environments. The impact of changes in nonshared environments on body weight can be estimated from biometrical genetical studies and is found to be both small and relatively short-lived. Genetic and environmental results from longitudinal studies are consistent with what is known about the changing distribution of adiposity during adulthood and clinical experience of the difficulty of maintaining behavioral-induced weight loss.     

The lifetime of automatic semantic priming effects may exceed two seconds

The N400 component of event-related potentials (ERPs) was obtained in a modified version of the Neely [J.H. Neely, Semantic priming and retrieval from lexical memory: Roles of inhibitionless spreading activation and limited-capacity attention, Journal of Experimental Psychology: General, Vol. 106 (1977), pp. 226-254.] paradigm which permits unconfounding of semantic priming effects due to automatic and attentional processes. It was found that a short stimulus onset asynchrony (SOA) of 250 ms between the prime and the target was associated with automatic but not expectancy effects on the amplitude of N400. At a long SOA of 2000 ms between prime and target, semantic priming effects on N400 were obtained associated with both automatic and expectancy processes. Moreover, there was no significance difference in the magnitude of the automatic effects at the two SOAs, suggesting that automatic processing had not decayed within the 2000 ms interval between the prime and target. The results support the two-processing interpretation of semantic priming advanced by Posner and Synder [M.I. Posner, C.R.R. Snyder, Attention and cognitive control, in: R.L. Solso (Ed.), Information Processing and Cognition: The Loyola Symposium, Erlbaum, Hillsdale, NJ (1975).] and concur with the results of Neely [J.H. Neely, Semantic priming and retrieval from lexical memory: Roles of inhibitionless spreading activation and limited-capacity attention, Journal of Experimental Psychology: General, Vol. 106 (1977), pp. 226-254], with the exception of indicating a longer persistence of automatic processes.     

Neuropsychological functioning and sleep patterns in the elderly.

OBJECTIVE: To discover whether reported sleep-wake disturbances in the elderly (more frequent nocturnal awakenings, earlier waking and more day time naps) are associated with neuropsychological dysfunction. DESIGN AND SETTING: A sample of 124 residents of a retirement village complex were interviewed about their sleep patterns and given neuropsychological assessments. Reported sleep-wake difficulties were combined to form two variables, "night sleep" and "day sleep". Additional sleep variables analysed were reported sleep duration and time of wakening. Principal components analysis of the neuropsychological test scores yielded four factors: "general ability", "memory", "motor", and "cerebral efficiency". MAIN OUTCOME MEASURES: A correlation analysis was performed for sleep variables, neuropsychological factors and age, mood scale and scores on indices of participation in physical and passive activities. RESULTS: There was no correlation between "night sleep" and the factor scores derived from the neuropsychological tests. "Day sleep" was correlated with "cerebral efficiency" only. Age was correlated with the "memory" and "motor" factors, the latter also being associated with participation in physical activities. CONCLUSION: Night sleep problems are not associated with neuropsychological deficits in a non-clinic population.     

The structure of schizotypy: a pilot multitrait twin study

This report of a pilot study examines 29 pairs of twins from a population-based registry on whom four domains of schizotypy have been measured: personal interview using the Structured Interview for Schizotypy, self-report questionnaire formed from eight published self-report scales, attentional battery of eight individual tests, and root mean square error on smooth pursuit eye tracking. Analyzing the twins as individuals revealed two independent dimensions of clinically rated schizotypy (positive symptom schizotypy and negative symptom schizotypy) and two independent dimensions of self-rated schizotypy (positive trait schizotypy and trait anhedonia). Positive symptom schizotypy was highly correlated with positive trait schizotypy, but not with attentional dysfunction or eye-tracking error. By contrast, negative symptom schizotypy was significantly related to trait anhedonia, attentional dysfunction, and eye-tracking error. Correlations in monozygotic and dizygotic twins suggested that genetic factors were important in all four domains of schizotypy. Except for eye-tracking error, the results are more consistent with a dimensional than a "disease" model of schizotypy. Replication of these results with a larger group of subjects is needed.     

Childhood obesity: the infancy connection

The prevalence of overweight has risen to 19% in children aged 6 to 11 years and 17% in adolescents aged 12 to 19 years. This paper examines gestational and infancy factors that influence the risk of overweight in childhood. Important factors to eliminate the infancy connection to childhood obesity include the following: (a) maternal lifestyle patterns, (b) infant feeding transitions, and (c) environmental factors. Prevention efforts need to focus on practice, research, and public policy.