2,310 research outputs found

    A longitudinal study of factors associated with acute and chronic mastitis and their impact on lamb growth rate in 10 suckler sheep flocks in Great Britain

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    A 2-year prospective, longitudinal study of 10 suckler sheep flocks in Great Britain was run to identify factors associated with acute mastitis (AM) and chronic mastitis, and their impact on lamb growth rate. Data were collected on AM, intramammary masses (IMM; a marker for chronic mastitis), udder and teat conformation, teat lesions, body condition, ewe nutrition, litter size, lamb weight and general flock management. Each flock was visited twice each year, approximately 4 weeks before lambing and 9 weeks into lactation, for two years and all ewes present at a visit were examined. There were 7021 examinations in total. AM was reported in 2.1–3.0% of ewes/year; this ranged from 0.0% to 37.1% by flock. IMM were detected in 4.7% of ewes in pregnancy and 10.9% of ewes in lactation. Once an IMM had been detected there was an increased risk of future IMM although IMM were not consistently present. The majority of ewes had good udder conformation to suckle lambs. Factors associated with AM, IMM in pregnant and lactating ewes, udder conformation and lamb daily live weight gain were explored using mixed effect multivariable models. An increased risk of AM was associated with underfeeding protein in pregnancy (OR 4.05), forward pointing teats (OR 2.54), downward pointing teats (OR 4.68), rearing ≥ 2 lambs (OR 2.65), non-traumatic teat lesions (OR 2.09); and marginally associated with the presence of IMM. An increased risk of IMM in lactation was associated with AM during lactation (OR 12.39), IMM in pregnancy (OR 4.79), IMM in the previous lactation (OR 4.77), underfeeding energy in pregnancy (OR 6.66) and traumatic teat lesions (OR 2.48). An increased risk of IMM in pregnancy was associated with IMM in the previous pregnancy, IMM in the previous lactation and underfeeding energy in the previous lactation (OR 2.95). Lower lamb daily live weight gain was associated with traumatic teat lesions, IMM in lactation (−0.01 kg/day) and AM (−0.04 kg/day). We conclude that inadequate nutrition is an important cause of mastitis in suckler ewes which farmers could address in part using current nutritional guidelines but further work is needed. The relationship between AM and IMM indicates that separating or culling ewes with IMM would help reduce AM

    Are Microbes Fundamentally Different Than Macroorganisms? Convergence and a Possible Case for Neutral Phenotypic Evolution in Testate Amoeba (Amoebozoa: Arcellinida)

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    This study reveals extensive phenotypic convergence based on the non-monophyly of genera and morphospecies of testate (shelled) amoebae. Using two independent markers, small subunit ribosomal DNA (ssu-rDNA) and mitochondrial cytochrome oxidase I (COI), we demonstrate discordance between morphology and molecules for ‘core Nebela’ species (Arcellinida; Amoebozoa). Prior work using just a single locus, ssu-rDNA, also supported the non-monophyly of the genera Hyalosphenia and Nebela as well as for several morphospecies within these genera. Here, we obtained COI gene sequences of 59 specimens from seven morphospecies and ssu-rDNA gene sequences of 50 specimens from six morphospecies of hyalosphenids. Our analyses corroborate the prior ssu-rDNA findings of morphological convergence in test (shell) morphologies, as COI and ssu-rDNA phylogenies are concordant. Further, the monophyly of morphospecies is rejected using approximately unbiased tests. Given that testate amoebae are used as bioindicators in both palaeoecological and contemporary studies of threatened ecosystems such as bogs and fens, understanding the discordance between morphology and genetics in the hyalosphenids is essential for interpretation of indicator species. Further, while convergence is normally considered the result of natural selection, it is possible that neutrality underlies phenotypic evolution in these microorganisms

    Heritability of phenotypic udder traits to improve resilience to mastitis in Texel ewes

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    There are no estimates of the heritability of phenotypic udder traits in suckler sheep, which produce meat lambs, and whether these are associated with resilience to mastitis. Mastitis is a common disease which damages the mammary gland and reduces productivity. The aims of this study were to investigate the feasibility of collecting udder phenotypes, their heritability and their association with mastitis in suckler ewes. Udder and teat conformation, teat lesions, intramammary masses (IMM) and litter size were recorded from 10 Texel flocks in Great Britain between 2012 and 2014; 968 records were collected. Pedigree data were obtained from an online pedigree recording system. Univariate quantitative genetic parameters were estimated using animal and sire models. Linear mixed models were used to analyse continuous traits and generalised linear mixed models were used to analyse binary traits. Continuous traits had higher heritabilities than binary with teat placement and teat length heritability (h2) highest at 0.35 (SD 0.04) and 0.42 (SD 0.04), respectively. Udder width, drop and separation heritabilities were lower and varied with udder volume. The heritabilities of IMM and teat lesions (sire model) were 0.18 (SD 0.12) and 0.17 (SD 0.11), respectively. All heritabilities were sufficiently high to be in a selection programme to increase resilience to mastitis in the population of Texel sheep. Further studies are required to investigate genetic relationships between traits and to determine whether udder traits predict IMM, and the potential benefits from including traits in a selection programme to increase resilience to chronic mastitis

    Live quantitative monitoring of mineral deposition in stem cells using tetracycline hydrochloride

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    The final stage of in vitro osteogenic differentiation is characterized by the production of mineral deposits containing calcium cations and inorganic phosphates, which populate the extracellular matrix surrounding the cell monolayer. Conventional histological techniques for the assessment of mineralization, such as Von Kossa and Alizarin Red S staining, are end-point techniques requiring cell fixation. Moreover, in both cases staining quantitation requires dye extraction which irreversibly alters the ECM conformation and structure, therefore preventing the use of the sample for further analysis. In this study, the use of Tetracycline hydrochloride (TC) is proposed for the non-destructive staining, quantitation and imaging of mineralizing bone-like nodules in live cultures of human bone marrow mesenchymal stem cells (MSCs) cultured under osteogenic conditions. Overnight administration of TC to living cells was shown not to alter the metabolic activity or the progression of cell differentiation. When applied to differentiating cultures, cell exposure to serial doses of TC was found to produce quantifiable fluorescence emission specifically in osteogenic cultures. Incubation with TC enabled fluorescence imaging of mineralised areas in live cultures and the combination with other fluorophores using appropriate filters. These results demonstrate that serial TC administration over the differentiation time course provides a qualitative and quantitative tool for the monitoring and evaluation of the differentiation process in live cells

    Morphological Description of Telaepolella tubasferens n. g., n. sp., Isolate ATCC© 50593™, a Filose Amoeba in the Gracilipodida, Amoebozoa

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    We describe the amoeboid isolate ATCC© 50593™ as a new taxon, Telaepolella tubasferens n. gen. n. sp. This multinucleated amoeba has filose pseudopods and is superficially similar to members of the vampyrellids (Rhizaria) such as Arachnula impatiens Cienkowski, 1876, which was the original identification upon deposition. However, previous multigene analyses place this taxon within the Gracilipodida Lahr and Katz 2011 in the Amoebozoa. Here, we document the morphology of this organism at multiple life history stages and describe data underlying the description as a new taxon. We demonstrate that T. tubaspherens is distinct from Arachnula and other rhizarians (Theratromyxa, Leptophrys) in a suite of morphological characters such as general body shape, relative size of pseudopods, distinction of ecto- and endoplasmic regions, and visibility of nuclei in non-stained cells (an important diagnostic character). Although Amoebozoa taxa generally have lobose pseudopods, genera in Gracilipodida such as Flamella and Filamoeba as well as several organisms previously classified as protosteloid amoebae (e.g. schizoplasmodiis, cavosteliids and Stemonitales) present filose pseudopodia. Thus, classification of amoeboid organisms merely by filose-lobose distinction must be reconsidered

    Development of Fetal Movement Between 26 and 36 Weeks’ Gestation in Response to Vibroacoustic Stimulation

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    BACKGROUND: Ultrasound observation of fetal movement has documented general trends in motor development and fetal age when motor response to stimulation is observed. Evaluation of fetal movement quality, in addition to specific motor activity, may improve documentation of motor development and highlight specific motor responses to stimulation. AIM: The aim of this investigation was to assess fetal movement at 26 and 36-weeks gestation during three conditions (baseline, immediate response to vibro-acoustic stimulation (VAS), and post-response). DESIGN: A prospective, longitudinal design was utilized. SUBJECTS: Twelve normally developing fetuses, eight females and four males, were examined with continuous ultrasound imaging. OUTCOME MEASURES: The fetal neurobehavioral coding system (FENS) was used to evaluate the quality of motor activity during 10-s epochs over the three conditions. RESULTS: Seventy-five percent of the fetuses at the 26-week assessment and 100% of the fetuses at the 36-week assessment responded with movement immediately following stimulation. Significant differences in head, fetal breathing, general, limb, and mouthing movements were detected between the 26 and 36-week assessments. Movement differences between conditions were detected in head, fetal breathing, limb, and mouthing movements. CONCLUSION: Smoother and more complex movement was observed with fetal maturation. Following VAS stimulation, an immediate increase of large, jerky movements suggests instability in fetal capabilities. Fetal movement quality changes over gestation may reflect sensorimotor synaptogenesis in the central nervous system, while observation of immature movement patterns following VAS stimulation may reflect movement pattern instability

    Vitreous Bands Identified by Handheld Spectral-Domain Optical Coherence Tomography Among Premature Infants

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    Importance: Handheld spectral-domain optical coherence tomography (SD-OCT) can provide insights into the complex interactions occurring at the vitreoretinal interface in retinopathy of prematurity (ROP) to enhance our understanding of ROP pathology. Objective: To characterize vitreous bands in premature infants with use of handheld SD-OCT. Design, Setting, and Participants: Prospective cohort study conducted from July 7, 2015, to February 28, 2017, at 2 university-based neonatal intensive care units. Seventy-three premature infants who required routine ROP screening examination were recruited. Informed consent was obtained from all legal guardians. Trained graders who were masked to the clinical assessment analyzed each SD-OCT scan of the right eye for vitreoretinal findings. A third trained grader mediated disagreements. Main Outcomes and Measures: Associations between the presence of vitreous bands in premature infants with ROP diagnoses and the presence of other vitreoretinal SD-OCT findings were investigated. Results: Of the 73 infants recruited, 6 infants\u27 parents withdrew their children from the study, and 2 infants were too hemodynamically unstable for imaging, leaving a total of 65 participants. Of these, 32 (49%) were female, 36 (55%) were white, 10 (15%) were Hispanic, 3 (5%) were Native American, 4 (6%) were African American, 4 (7%) were Asian/Pacific Islander, and 8 (12%) were other. The mean (SD) gestational age was 28 (2.7) weeks, the mean (SD) birth weight was 997 g (286 g), and the mean (SD) postmenstrual age at imaging was 34 (3) weeks (mean [SD] total of 3 [2] imaging sessions). Comparing the 24 infants (37%) who had a right eye vitreous band at any time with the 41 (63%) who did not, no difference in mean birth weight, gestational age, postmenstrual age at imaging, sex, or race/ethnicity was identified. No associations with ROP stage (eg, in 6 [25%] infants with vitreous bands vs 4 [9.8%] in those without; P = .23), presence of plus disease (2 [8%] vs 2 [5%]; P = .84), or type 1 ROP (3 [12%] vs 3 [7%]; P = .66) were identified. Vitreous bands were associated with epiretinal membrane detected on SD-OCT (P = .001) with an odds ratio of 9.4 (95% CI, 2.8-31.3) in 15 [62%] infants with vitreous bands vs 6 [15%] in those without. Vitreous bands were also associated with cystoid macular edema (in 15 [62%] infants with vitreous bands vs 1 [27%] in those without; P = .005) with an odds ratio of 4.5 (95% CI, 1.5-13.3). Conclusions and Relevance: In this study, the development of vitreous bands was associated with both cystoid macular edema and epiretinal membrane. These findings suggest a tractional pathogenesis to these entities among premature infants. This study did not find a direct association between vitreous bands and severe ROP. Additional study is needed to determine whether vitreous bands represent subclinical hyaloidal organization leading to retinal detachment in advanced ROP

    The contribution of physician assistants/associates to secondary care : a systematic review

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    OBJECTIVE: To appraise and synthesise research on the impact of physician assistants/associates (PA) in secondary care, specifically acute internal medicine, care of the elderly, emergency medicine, trauma and orthopaedics, and mental health. DESIGN: Systematic review. SETTING: Electronic databases (Medline, Embase, ASSIA, CINAHL, SCOPUS, PsycINFO, Social Policy and Practice, EconLit and Cochrane), reference lists and related articles. INCLUDED ARTICLES: Peer-reviewed articles of any study design, published in English, 1995-2017. INTERVENTIONS: Blinded parallel processes were used to screen abstracts and full text, data extractions and quality assessments against published guidelines. A narrative synthesis was undertaken. OUTCOME MEASURES: Impact on: patients' experiences and outcomes, service organisation, working practices, other professional groups and costs. RESULTS: 5472 references were identified and 161 read in full; 16 were included-emergency medicine (7), trauma and orthopaedics (6), acute internal medicine (2), mental health (1) and care of the elderly (0). All studies were observational, with variable methodological quality. In emergency medicine and in trauma and orthopaedics, when PAs are added to teams, reduced waiting and process times, lower charges, equivalent readmission rate and good acceptability to staff and patients are reported. Analgesia prescribing, operative complications and mortality outcomes were variable. In internal medicine outcomes of care provided by PAs and doctors were equivalent. CONCLUSIONS: PAs have been deployed to increase the capacity of a team, enabling gains in waiting time, throughput, continuity and medical cover. When PAs were compared with medical staff, reassuringly there was little or no negative effect on health outcomes or cost. The difficulty of attributing cause and effect in complex systems where work is organised in teams is highlighted. Further rigorous evaluation is required to address the complexity of the PA role, reporting on more than one setting, and including comparison between PAs and roles for which they are substituting. PROSPERO REGISTRATION NUMBER: CRD42016032895

    Nutrition and the circadian system

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    The human circadian system anticipates and adapts to daily environmental changes to optimise behaviour according to time of day and temporally partitions incompatible physiological processes. At the helm of this system is a master clock in the suprachiasmatic nuclei (SCN) of the anterior hypothalamus. The SCN are primarily synchronised to the 24-h day by the light/dark cycle; however, feeding/fasting cycles are the primary time cues for clocks in peripheral tissues. Aligning feeding/fasting cycles with clock-regulated metabolic changes optimises metabolism, and studies of other animals suggest that feeding at inappropriate times disrupts circadian system organisation, and thereby contributes to adverse metabolic consequences and chronic disease development. ‘High-fat diets’ (HFD) produce particularly deleterious effects on circadian system organisation in rodents by blunting feeding/fasting cycles. Time-of-day-restricted feeding, where food availability is restricted to a period of several hours, offsets many adverse consequences of HFD in these animals; however, further evidence is required to assess whether the same is true in humans. Several nutritional compounds have robust effects on the circadian system. Caffeine, for example, can speed synchronisation to new time zones after jetlag. An appreciation of the circadian system has many implications for nutritional science and may ultimately help reduce the burden of chronic diseases

    Antarctic Climate Change and the Environment: A Decadal Synopsis and Recommendations for Action

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    Scientific evidence is abundantly clear and convincing that due to the current trajectory of human-derived emissions of CO2 and other greenhouse gases, the atmosphere and ocean will continue to warm, the ocean will continue to acidify, atmospheric and ocean circulation patterns will be altered, the cryosphere will continue to lose ice in all forms, and sea level will rise
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