Ultrasensitive PCR system for HBV DNA detection: Risk stratification for occult hepatitis B virus infection in English blood donors

Occult hepatitis B (HBV) infection (OBI), characterized by low viral loads, accounts for much of the risk of HBV transfusion-transmitted infection. With anticore antibodies (anti-HBc) screening introduced in England, the imperative to identify OBI donors has increased. We aimed to develop an ultra-sensitive PCR system and investigate risk factors for HBV DNA presence in blood donations. Seven extraction methods and three PCR assays were compared. The optimal system was sought to determine HBV DNA presence in anti-HBc-positive donations. Predictors of DNA positivity were subsequently investigated. Extraction from 5 mL of plasma increased sample representation and resulted in HBV DNA detection in low viral load samples (~0.5 IU/mL). Screening of 487 763 donations in 2022 identified two OBI donors and 2042 anti-HBc-positive donors, 412 of the latter with anti-HBs < 100 mIU/mL. Testing of 134 anti-HBc-positive donations utilizing the 5 mL extraction method identified two further HBV DNA-positive donations. Higher anti-HBc titer and anti-HBs negativity were significant predictors of DNA detectability in anti-HBc-positive donations. An ultrasensitive PCR assay identified potentially infectious donations increasing HBV DNA detection in anti-HBc-positive donors from 0.5% to 1.9%. Anti-HBc titers may further complement the risk stratification for DNA positivity in anti-HBc screening and minimize unnecessary donor deferral

Animal Health and Welfare Issues Facing Organic Production Systems

The demand for organically-grown produce is increasing worldwide, with one of the drivers being an expectation among consumers that animals have been farmed to a high standard of animal welfare. This review evaluates whether this expectation is in fact being met, by describing the current level of science-based knowledge of animal health and welfare in organic systems. The primary welfare risk in organic production systems appears to be related to animal health. Organic farms use a combination of management practices, alternative and complementary remedies and convenional medicines to manage the health of their animals and in many cases these are at least as effective as management practices employed by non-organic producers. However, in contrast to non-organic systems, there is still a lack of scientifically evaluated, organically acceptable therapeutic treatments that organic animal producers can use when current management practices are not sufficient to maintain the health of their animals. The development of such treatments are necessary to assure consumers that organic animal-based food and fibre has not only been produced with minimal or no chemical input, but under high standards of animal welfare

Animal Health and Welfare Issues Facing Organic Production Systems

The demand for organically-grown produce is increasing worldwide, with one of the drivers being an expectation among consumers that animals have been farmed to a high standard of animal welfare. This review evaluates whether this expectation is in fact being met, by describing the current level of science-based knowledge of animal health and welfare in organic systems. The primary welfare risk in organic production systems appears to be related to animal health. Organic farms use a combination of management practices, alternative and complementary remedies and convenional medicines to manage the health of their animals and in many cases these are at least as effective as management practices employed by non-organic producers. However, in contrast to non-organic systems, there is still a lack of scientifically evaluated, organically acceptable therapeutic treatments that organic animal producers can use when current management practices are not sufficient to maintain the health of their animals. The development of such treatments are necessary to assure consumers that organic animal-based food and fibre has not only been produced with minimal or no chemical input, but under high standards of animal welfare

Impact of nutritional supplementation on immune response, body mass index and bioelectrical impedance in HIV-positive patients starting antiretroviral therapy

Abstract Background: Challenges to HIV care in resource limited settings (RLS) include malnutrition. Limited evidence supports the benefit of nutritional supplementation when starting antiretroviral therapy (ART) in RLS

Quality out of Control: Standards for Measuring Architecture

Formerly grounded in values of craftsmanship, in the skilled making of products, `quality' is now associated with the management of administrative or technical processes. Its appreciation, once based in the exercise of individual judgement and taste, is now often founded on supposedly objective systems of evaluation.Practitioners of design are under pressure to quantify `quality', but it is questionable whether it is possible or even desirable to do so. This book considers this important issue, looking at how quality is:defined, appreciated, evaluated, managed, produced.With contributions from eminent architects and architectural critics, this book is for architects, academics, students and anyone interested in what architectural quality is, and how it may be achieved

Convalescent plasma donors show enhanced cross-reactive neutralizing antibody response to antigenic variants of SARS-CoV-2 following immunization

Background The therapeutic benefit of convalescent plasma (CP) therapy to treat COVID-19 may derive from neutralizing antibodies (nAbs) to SARS-CoV-2. To investigate the effects of antigenic variation on neutralization potency of CP, we compared nAb titers against prototype and recently emerging strains of SARS-CoV-2, including Delta and Omicron, in CP donors previously infected with SARS-CoV-2 before and after immunization. Methods and Materials Samples were assayed from previously SARS-CoV-2 infected donors before (n = 17) and after one (n = 43) or two (n = 71) doses of Astra-Zeneca or Pfizer vaccinations. Ab titers against Wuhan/wild type (WT), Alpha, Beta, and Delta SARS-CoV-2 strains were determined by live virus microneutralization assay while titers to Omicron used a focus reduction neutralization test. Anti-spike antibody was assayed by Elecsys anti-SARS-CoV-2 quantitative spike assay (Roche). Results Unvaccinated donors showed a geometric mean titer (GMT) of 148 against WT, 80 against Alpha but mostly failed to neutralize Beta, Delta, and Omicron strains. Contrastingly, high GMTs were observed in vaccinated donors against all SARS-CoV-2 strains after one vaccine dose (WT:703; Alpha:692; Beta:187; Delta:215; Omicron:434). By ROC analysis, reactivity in the Roche quantitative Elecsys spike assay of 20,000 U/mL was highly predictive of donations with nAb titers of ≥1:640 against Delta (90% sensitivity; 97% specificity) and ≥1:320 against Omicron (89% sensitivity; 81% specificity). Discussion Vaccination of previously infected CP donors induced high levels of broadly neutralizing antibodies against circulating antigenic variants of SARS-CoV-2. High titer donations could be reliably identified by automated quantitative anti-spike antibody assay, enabling large-scale preselection of high-titer convalescent plasma

Long tails matter in sugarbirds--positively for extrapair but negatively for within-pair fertilization success

Extrapair mating is known to occur in many animals and potentially has a significant influence on reproductive success. Female extrapair mate choice may explain the occurrence of exaggerated ornaments in socially monogamous species, but the influence of ornamentation on extrapair mating success has rarely been investigated experimentally. Cape sugarbirds (Promerops cafer) are socially monogamous, almost always lay 2 egg clutches and have long-term pair bonds often lasting several seasons. However, they also display sexually dimorphic extravagant ornamentation in the form of a long, graduated tail and have one of the highest rates (65% of young) of extrapair paternity recorded in birds. We provide a test of the hypothesis that the ornamented tail is used in mate choice for extrapair partners by conducting an experiment in which tail length was manipulated after social mating but before copulation. This experiment therefore allowed females to respond to the manipulation of male tail length when making a choice of copulation partner but not social mate. We show that the tail length of male sugarbirds has a significant effect on the success of males in gaining extrapair paternity, with long-tailed males obtaining significantly more extrapair young than short-tailed males. However, males with short tails sire a significantly greater proportion of the nestlings in their own nests than long-tailed individuals. This result suggests that males may adopt alternative strategies dependent on their ornamentation. Copyright 2009, Oxford University Press.