Various bone parameters are positively correlated with hen body weight while range access has no beneficial effect on tibia health of free-range layers

The aim of this study was to determine if body weight or range use has a significant impact on bone health in commercial free-range laying hens, and to correlate tibia bone quality parameters with individual range usage and body weight. A total of 30 Lohmann Brown hens at 74 wk of age were selected from a commercial free-range farm and were either classified as heavy (mean ± SEM body weight 2.11 ± 0.034 kg, n = 14) or light (1.68 ± 0.022 kg, n = 16) body weight, and also classified as rangers (accessed the range for 86.7% of available days, n = 16) or stayers (accessed the range for 5.00% of available days, n = 14). The left tibiae of all individuals were analyzed for morphological parameters using computed tomography, evaluated for bone breaking strength, and ashed to determine mineral composition. Keel bone scoring was performed based on observation. Data were analyzed using a 2 × 2 factorial ANOVA, and regression analysis was performed. There was no measurable effect of range usage on any of the tibia parameters investigated. The body weight was significantly correlated with tibia breaking strength (r = 0.59), tibia weight (r = 0.56), tibia length (r = 0.64), diaphyseal diameter (r = 0.61), and total tibia volume (r = 0.67). In conclusion, range access had no beneficial effect on bone health. The impact of internal hen house furnishing and movement on bone health needs further investigation

Crystal structure of DNA-PKcs reveals a large open-ring cradle comprised of HEAT repeats.

Broken chromosomes arising from DNA double-strand breaks result from endogenous events such as the production of reactive oxygen species during cellular metabolism, as well as from exogenous sources such as ionizing radiation. Left unrepaired or incorrectly repaired they can lead to genomic changes that may result in cell death or cancer. DNA-dependent protein kinase (DNA-PK), a holoenzyme that comprises the DNA-PK catalytic subunit (DNA-PKcs) and the heterodimer Ku70/Ku80, has a major role in non-homologous end joining-the main pathway in mammals used to repair double-strand breaks. DNA-PKcs is a serine/threonine protein kinase comprising a single polypeptide chain of 4,128 amino acids and belonging to the phosphatidylinositol-3-OH kinase (PI(3)K)-related protein family. DNA-PKcs is involved in the sensing and transmission of DNA damage signals to proteins such as p53, setting off events that lead to cell cycle arrest. It phosphorylates a wide range of substrates in vitro, including Ku70/Ku80, which is translocated along DNA. Here we present the crystal structure of human DNA-PKcs at 6.6 A resolution, in which the overall fold is clearly visible, to our knowledge, for the first time. The many alpha-helical HEAT repeats (helix-turn-helix motifs) facilitate bending and allow the polypeptide chain to fold into a hollow circular structure. The carboxy-terminal kinase domain is located on top of this structure, and a small HEAT repeat domain that probably binds DNA is inside. The structure provides a flexible cradle to promote DNA double-strand-break repair

Ancient and Recent Adaptive Evolution of Primate Non-Homologous End Joining Genes

In human cells, DNA double-strand breaks are repaired primarily by the non-homologous end joining (NHEJ) pathway. Given their critical nature, we expected NHEJ proteins to be evolutionarily conserved, with relatively little sequence change over time. Here, we report that while critical domains of these proteins are conserved as expected, the sequence of NHEJ proteins has also been shaped by recurrent positive selection, leading to rapid sequence evolution in other protein domains. In order to characterize the molecular evolution of the human NHEJ pathway, we generated large simian primate sequence datasets for NHEJ genes. Codon-based models of gene evolution yielded statistical support for the recurrent positive selection of five NHEJ genes during primate evolution: XRCC4, NBS1, Artemis, POLλ, and CtIP. Analysis of human polymorphism data using the composite of multiple signals (CMS) test revealed that XRCC4 has also been subjected to positive selection in modern humans. Crystal structures are available for XRCC4, Nbs1, and Polλ; and residues under positive selection fall exclusively on the surfaces of these proteins. Despite the positive selection of such residues, biochemical experiments with variants of one positively selected site in Nbs1 confirm that functions necessary for DNA repair and checkpoint signaling have been conserved. However, many viruses interact with the proteins of the NHEJ pathway as part of their infectious lifecycle. We propose that an ongoing evolutionary arms race between viruses and NHEJ genes may be driving the surprisingly rapid evolution of these critical genes

Demographic, socio-economic, and cultural factors affecting fertility differentials in Nepal

<p>Abstract</p> <p>Background</p> <p>Traditionally Nepalese society favors high fertility. Children are a symbol of well-being both socially and economically. Although fertility has been decreasing in Nepal since 1981, it is still high compared to many other developing countries. This paper is an attempt to examine the demographic, socio-economic, and cultural factors for fertility differentials in Nepal.</p> <p>Methods</p> <p>This paper has used data from the Nepal Demographic and Health Survey (NDHS 2006). The analysis is confined to ever married women of reproductive age (8,644). Both bivariate and multivariate analyses have been performed to describe the fertility differentials. The bivariate analysis (one-way ANOVA) was applied to examine the association between children ever born and women's demographic, socio-economic, and cultural characteristics. Besides bivariate analysis, the net effect of each independent variable on the dependent variable after controlling for the effect of other predictors has also been measured through multivariate analysis (multiple linear regressions).</p> <p>Results</p> <p>The mean numbers of children ever born (CEB) among married Nepali women of reproductive age and among women aged 40-49 were three and five children, respectively. There are considerable differentials in the average number of children ever born according to women's demographic, socio-economic, and cultural settings. Regression analysis revealed that age at first marriage, perceived ideal number of children, place of residence, literacy status, religion, mass media exposure, use of family planning methods, household headship, and experience of child death were the most important variables that explained the variance in fertility. Women who considered a higher number of children as ideal (β = 0.03; p < 0.001), those who resided in rural areas (β = 0.02; p < 0.05), Muslim women (β = 0.07; p < 0.001), those who had ever used family planning methods (β = 0.08; p < 0.001), and those who had a child-death experience (β = 0.31; p < 0.001) were more likely to have a higher number of CEB compared to their counterparts. On the other hand, those who married at a later age (β = -0.15; p < 0.001), were literate (β = -0.05; p < 0.001), were exposed to both (radio/TV) mass media (β = -0.05; p < 0.001), were richest (β = -0.12; p < 0.001), and were from female-headed households (β = -0.02; p < 0.05) had a lower number of children ever born than their counterparts.</p> <p>Conclusion</p> <p>The average number of children ever born is high among women in Nepal. There are many contributing factors for the high fertility, among which are age at first marriage, perceived ideal number of children, literacy status, mass media exposure, wealth status, and child-death experience by mothers. All of these were strong predictors for CEB. It can be concluded that programs should aim to reduce fertility rates by focusing on these identified factors so that fertility as well as infant and maternal mortality and morbidity will be decreased and the overall well-being of the family maintained and enhanced.</p

Longer hospital stay is associated with higher rates of tuberculosis-related morbidity and mortality within 12 months after discharge in a referral hospital in Sub-Saharan Africa

BACKGROUND: Nosocomial transmission of pulmonary tuberculosis (PTB) is a problem in resource-limited settings. However, the degree of TB exposure and the intermediate- and long-term morbidity and mortality of hospital-associated TB is unclear. In this study we determined: 1) the nature, patterns and intensity of TB exposure occurring in the context of current TB cohorting practices in medical centre with a high prevalence of TB and HIV; 2) the one-year TB incidence after discharge; and 3) one-year TB-related mortality after hospital discharge. METHODS: Factors leading to nosocomial TB exposure were collected daily over a 3-month period. Patients were followed for 1-year after discharge. TB incidence and mortality were calculated and logistic regression was used to determine the factors associated with TB incidence and mortality during follow up. RESULTS: 1,094 patients were admitted to the medical wards between May 01 and July 31, 2010. HIV was confirmed in 690/1,094 (63.1%) of them. A total of 215/1,094 (19.7%) patients were diagnosed with PTB and 178/1,094 (16.3%) patients died during the course of their hospitalization; 12/178 (6.7%) patients died from TB-related complications. Eventually, 916 (83.7%) patients were discharged and followed for one year after it. Of these, 51 (5.6%) were diagnosed with PTB during the year of follow up (annual TB rate of 3,712 cases per 100,000 person per year). Overall, 57/916 (6.2%) patients died during the follow up period, of whom 26/57 (45.6%) died from confirmed TB. One-year TB incidence rate and TB-associated mortality were associated with the number of days that the patient remained hospitalized, the number of days spent in the cohorting bay (regardless of whether the patient was eventually diagnosed with TB or not), and the number and proximity to TB index cases. There was no difference in the performance of each of these 3 measurements of nosocomial TB exposure for the prediction of one-year TB incidence. CONCLUSION: Substantial TB exposure, particularly among HIV-infected patients, occurs in nosocomial settings despite implementation of cohorting measures. Nosocomial TB exposure is strongly associated with one-year TB incidence and TB-related mortality. Further studies are needed to identify strategies to reduce such exposure among susceptible patients

Atopy Is Inversely Related to Schistosome Infection Intensity: A Comparative Study in Zimbabwean Villages with Distinct Levels of <i>Schistosoma haematobium</i> Infection

This is the peer-reviewed but unedited manuscript version of the following article:Rujeni, N., et al. (2012). "Atopy Is Inversely Related to Schistosome Infection Intensity: A Comparative Study in Zimbabwean Villages with Distinct Levels of Schistosoma haematobium Infection." International Archives of Allergy and Immunology 158(3): 288-298.. The final, published version is available at http://www.karger.com/DOI: 10.1159/000332949e World Health Organization (Grant No. RPC264), The Welcome Trust (Grant No. WT082028MA), the University of Edinburgh and the government of Rwanda

Feeding hens in a loose husbandry system - challenges and consequences on performance and welfare

Housing hens in loose husbandry systems such as barn, free-range, or organic systems is associated with many challenges that not only interfere with body weight uniformity, but also with adequate feed intake, as well as high inter-hen variation of nutrient and energy requirements. This brief review outlines recent findings about the characterisation of sub-populations within free-range flocks, and highlights their impact on flock performance and dietary considerations. Ongoing work with these subpopulations including determining of metabolic needs, clustering of various performance groups and hens of different health status within one flock may allow for distinct pattern recognition and targeted dietary management using different geographical locations within the hen house. Given the fact that subpopulations oflayer flocks in experimental and commercial free-range facilities are commonly observed, the use of modern technology including routine Radio-Frequency Identification (RFID ), location sensing and computed learning should be considered to improve current feeding strategies, allowing realtime flock management for a more economic, efficient and sustainable use of feed resources