Biological Explanations (biological + explanation)

Distribution by Scientific Domains

Selected Abstracts

Nocturnal sleep duration and cognitive impairment in a population-based study of older adults

Adrian Loerbroks
Abstract Objective We aimed to investigate the association between nocturnal sleep duration, changes in nocturnal sleep duration and cognitive impairment in older adults. Methods 4010 participants of a population-based cohort study provided information on nocturnal sleep duration at baseline (1991,1995) and at follow-up (2002/2003). 792 follow-up participants aged 70+ by 2006 participated in telephone-based cognitive assessments. Several cognitive tests were used including the telephone interview for cognitive status (TICS). Cognitive impairment was defined as <31 points on the TICS (13.0%) and as below this percentile on the other tests. Based on individual tests, a verbal memory score and a total score were constructed. Multivariable prevalence ratios (PRs) of cognitive impairment and 95% confidence intervals (95%CIs) were computed using Poisson regression. Analyses were restricted to those free of depression in 2002/2003 (n,=,695). Results Sleeping ,6 or 8,h per night (versus 7,h) were unrelated to cognitive impairment. Sleeping ,9,h was positively, although imprecisely, associated with impairment of verbal memory (PR,=,1.7, 95%CI,=,1.0, 3.0), and less pronounced with the other cognitive measures. An increase in sleep duration from 7,8,h in 1992,1995 to ,9,h 8.5 years later (versus sleeping 7,8,h at both time points) was associated with an increased prevalence of cognitive impairment according to the TICS (PR,=,2.1, 95%,=,1.0, 4.5) and the verbal memory score (PR,=,2.0, 95%CI,=,1.0, 3.8). Conclusions Increases in sleep duration are associated with cognitive impairment. A biological explanation for this association is currently lacking. Increases in sleep duration could be a marker of cognitive deficits. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Guidelines for submitting adverse event reports for publication,,

FISPE (Chair), William N. Kelly Pharm D
Publication of case reports describing suspected adverse effects of drugs and medical products that include herbal and complementary medicines, vaccines, and other biologicals and devices is important for postmarketing surveillance. Publication lends credence to important signals raised in these adverse event reports. Unfortunately, deficiencies in vital information in published cases can often limit the value of such reports by failing to provide sufficient details for either (i) a differential diagnosis or provisional assessment of cause-effect association, or (ii) a reasonable pharmacological or biological explanation. Properly described, a published report of one or more adverse events can provide a useful signal of possible risks associated with the use of a drug or medical product which might warrant further exploration. A review conducted by the Task Force authors found that many major journals have minimal requirements for publishing adverse event reports, and some have none at all. Based on a literature review and our collective experience in reviewing adverse event case reports in regulatory, academic, and industry settings, we have identified information that we propose should always be considered for inclusion in a report submitted for publication. These guidelines have been endorsed by the International Society for Pharmacoepidemiology (ISPE) and the International Society of Pharmacovigilance (ISoP) and are freely available on the societies' web sites. Their widespread distribution is encouraged. ISPE and ISoP urge biomedical journals to adopt these guidelines and apply them to case reports submitted for publication. They also encourage schools of medicine, pharmacy, and nursing to incorporate them into the relevant curricula that address the detection, evaluation, and reporting of suspected drug or other medical product adverse events. Copyright © 2007 Kelly et al. Reproduced with permission by John Wiley & Sons, Ltd. [source]

BIOETHNIC CONSCRIPTION: Genes, Race, and Mexicana/o Ethnicity in Diabetes Research

This article is an examination of academic, corporate, and state-funded alliance of molecular, biological, computer, and clinical scientists who are conducting research into the genetic epidemiology of type 2 diabetes. Because type 2 diabetes affects human groups differently, researchers use ethnic and racial taxonomies to parse populations and social history to rationalize their categorical choices. In a process termed "bioethnic conscription," the social identities and life conditions of DNA donors are grafted into the biological explanations of human difference and disease causality in both objectionable and constructive ways. Bioethnic conscription is presented as an ethnographically sound alternative to the either,or proposition of the (R)ace,no race debate within biomedicine and anthropology. [source]

The concept of disease: ethical challenges and relevance to dentistry and dental education

Bjørn M. Hofmann
Modern medicine and dentistry face fundamental ethical challenges. To treat or not to treat, that is the question! Can these challenges be met with a rigorous and consistent concept of disease? This is the key question of this article and the ensuing debate is of fundamental importance in the teaching of ethics to medical and dental students. The investigation of traditional concepts of disease reveals that they are flawed and do not withstand ethical challenges. An alternative concept of human ailment is elaborated on, based on the triad disease, illness and sickness. This model is applied to representative cases in medicine in general and dentistry in particular. It is argued that the concepts of disease, illness and sickness represent a framework for analysing and coping with inherent ethical challenges. This reveals that medicine and dentistry are concerned both with biological explanations and with questions of the virtuous life, i.e., both with science and with ethics. These considerations pose challenges for the health professions as a whole, but particularly for those concerned with educating the practitioners of the future. [source]

Morningness in German and Spanish students: a comparative study

Christoph Randler
Abstract Humans show pronounced individual differences in circadian orientation. Transcultural comparisons are interesting since biological (or environmental) factors together with cultural ones may contribute to differences in morningness,eveningness. We compared Spanish and German undergraduates using the Composite Scale of Morningness (CSM) to assess circadian preferences. Confirmatory and multiple groups confirmatory factor analysis were used to assess factor structure and structural invariance across countries. The results showed that a three-factor model of morningness best characterises the CSM structure of both samples. Partial factorial invariance (factor loadings) across countries was demonstrated for the factors ,morningness' and ,morning alertness'. Scores of both factors were higher in German students. Potential cultural and biological explanations for the differences are discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source]


EVOLUTION, Issue 2 2000
Peter J. Wagner
Abstract., Frequencies of new character state derivations are analyzed for 56 fossil taxa. The hypothesis that new character states are added continuously throughout clade history can be rejected for 48 of theses clades. Two alternative explanations are considered: finite states and ordered states. The former hypothesizes a limited number of states available to each character and is tested using rarefaction equations. The latter hypothesizes that there are limited possible descendant morphologies for any state, even if the character has infinite potential states. This is tested using power functions. The finite states hypothesis explains states: steps relationships significantly better than does the ordered states hypothesis in 14 cases; the converse is true for 14 other cases. Under either hypothesis, trilobite clades show appreciably more homoplasy after the same numbers of steps than do molluscs, echinoderms, or vertebrates. The prevalence of the exhaustion pattern among different taxonomic groups implies that worker biases are not to blame and instead implicates biological explanations such as intrinsic constraints or persistent selective trends. Regardless of the source of increased homoplasy, clades appear to exhaust their available character spaces. Nearly all examined taxa show significant increases in proportions of incompatible character pairs (i.e., those necessarily implying homoplasy) as progressively younger taxa are added to character matrices. Thus, a deterioration of hierarchical structure accompanies character state exhaustion. Exhaustion has several implications: (1) the basic premise of cladistic analyses (i.e., that maximum congruence reflects homology rather than homoplasy) becomes increasingly less sound as clades age; (2) sampling high proportions of taxa probably is needed for congruence to discern homoplasy from homology; (3) stratigraphic data might be necessary to discern congruent homoplasy from congruent homology; and (4) in many cases, character states appear to have evolved in ordered patterns. [source]

Design , an inappropriate concept in evolutionary theory,

W. J. Bock
Abstract The concept of accident in evolution refers to causes which are stochastic with respect to selective demands arising from the external environment and acting on the organism, while the concept of design refers to causes which meet the requirement of these selective demands. The condition ,with respect to selective demands' is generally forgotten so that evolutionary changes are described as being design modifications. Design is an invalid synonym for adaptation. Further it implies a designer and has been used by some authors since before Darwin to argue that design in organisms demonstrates the existence of a designer and hence a plan. Yet if evolution depends on two simultaneously acting causes, one of which is accidental, then the process of evolution and all attributes of organisms are accidental. The concept of design is inappropriate in biology and should be eliminated from all biological explanations. [source]

Intake of calorically sweetened beverages and obesity

N. J. Olsen
Summary The prevalence of obesity has increased in the past 30 years, and at the same time a steep increase in consumption of soft drinks has been seen. This paper reviews the literature for studies on associations between intake of calorically sweetened beverages and obesity, relative to adjustment for energy intake. Conclusions from previous reviews have been inconsistent, but some included many cross-sectional studies or studies supported by sugar industry. A literature search was performed for prospective and experimental studies using Medline and Scirus. Fourteen prospective and five experimental studies were identified. The majority of the prospective studies found positive associations between intake of calorically sweetened beverages and obesity. Three experimental studies found positive effects of calorically sweetened beverages and subsequent changes in body fat. Two experimental studies did not find effects. Eight prospective studies adjusted for energy intake. Seven of these studies reported associations that were essentially similar before and after energy adjustment. In conclusion, a high intake of calorically sweetened beverages can be regarded as a determinant for obesity. However, there seems to be no support that the association between intake of calorically sweetened beverages and obesity is mediated via increased energy intake, and alternative biological explanations should be explored. [source]

Racial variation in the pattern and quality of care for prostate cancer in the USA: mind the gap

Daniel A. Barocas
This is a comment moderated paper. Please go to for further details. OBJECTIVE To review the literature on racial variation in the pattern of care (PoC) and quality of care (QoC) for prostate cancer, as there are known racial disparities in the incidence and outcomes of prostate cancer. While there are some biological explanations for these differences, they do not completely explain the variation. Differences in the appropriateness and QoC delivered to men of different racial groups may contribute to disparities in outcome. METHODS We searched the USA National Library of Medicine PubMed system for articles pertaining to quality indicators in prostate cancer and racial disparities in QoC for prostate cancer. RESULTS While standards for appropriate treatment are not clearly defined, racial variation in the PoC has been reported in several studies, suggesting that African-American men may receive less aggressive treatment. There are validated QoC indicators in prostate cancer, and researchers have begun to evaluate racial variation in adherence to these quality indicators. Further quality comparisons, particularly in structural measures, may need to be performed to fully evaluate differences in QoC. CONCLUSIONS There is mounting evidence for racial variation in the PoC and QoC for prostate cancer, which may contribute to observed differences in outcome. While some of the sources of racial variation in quality and outcome have been identified through the development of evidence-based guidelines and validated quality indicators, opportunities exist to identify, study and attempt to resolve other components of the quality gap. [source]