1,133 research outputs found
Feeding lower-protein diets based on red clover and grass or alfalfa and corn silage does not affect milk production but improves nitrogen use efficiency in dairy cows
Reducing the dietary crude protein (CP) concentration can decrease the financial cost and lower the environmental impact of milk production. Two studies were conducted to examine the effects of reducing the dietary CP concentration on animal performance, nutrient digestibility, milk fatty acid (FA) profile, and nitrogen use efficiency (NUE; milk N/N intake) in dairy cows fed legume silage-based diets. Thirty-six multiparous Holstein-Friesian dairy cows that were 76 ± 14 (mean ± SD) days in milk and 698 ± 54 kg body weight were used in a 3 × 3 Latin square design in each of 2 studies, with 3 periods of 28 d. In study 1, cows were fed diets based on a 50:50 ratio of red clover to grass silage [dry matter (DM) basis] containing 1 of 3 dietary CP concentrations: high (H) = 175 g of CP/kg of DM; medium (M) = 165 g of CP/kg of DM; or low (L) = 150 g of CP/kg of DM. In study 2, cows were fed 175 g of CP/kg of DM with a 50:50 ratio of alfalfa to corn silage (H50) or 1 of 2 diets containing 150 g of CP/kg of DM with either a 50:50 (L50) or a 60:40 (L60) ratio of alfalfa to corn silage. Cows in both studies were fed a total mixed ration with a forage-to-concentrate ratio of 52:48 (DM basis). All diets were formulated to meet the MP requirements, except L (95% of MP requirements). In study 1, cows fed L ate 1.6 kg of DM/d less than those fed H or M, but milk yield was similar across treatments. Mean milk protein, fat, and lactose concentrations were not affected by diet. However, the apparent total-tract nutrient digestibility was decreased in cows fed L. The NUE was 5.7 percentage units higher in cows fed L than H. Feeding L also decreased milk and plasma urea concentrations by 4.4 mg/dL and 0.78 mmol/L, respectively. We found no effect of dietary treatment on the milk saturated or monounsaturated FA proportion, but the proportion of polyunsaturated FA was increased, and milk odd- and branched-chain FA decreased in cows fed L compared with H. In study 2, DM intake was 2 kg/d lower in cows receiving L50 than H50. Increasing the alfalfa content and feeding a low-CP diet (L60) did not alter DMI but decreased milk yield and milk protein concentration by 2 kg/d and 0.6 g/kg, respectively, compared with H50. Likewise, milk protein and lactose yield were decreased by 0.08 kg/d in cows receiving L60 versus H50. Diet had no effect on apparent nutrient digestibility. Feeding the low-CP diets compared with H50 increased the apparent NUE by approximately 5 percentage units and decreased milk and plasma urea concentrations by 7.2 mg/dL and 1.43 mmol/L, respectively. Dietary treatment did not alter milk FA profile except cis-9,trans-11 conjugated linoleic acid, which was higher in milk from cows receiving L60 compared with H50. We concluded that reducing CP concentration to around 150 g/kg of DM in red clover and grass or alfalfa and corn silage-based diets increases the apparent NUE and has little effect on nutrient digestibility or milk performance in dairy cows
Ergodic properties of a model for turbulent dispersion of inertial particles
We study a simple stochastic differential equation that models the dispersion
of close heavy particles moving in a turbulent flow. In one and two dimensions,
the model is closely related to the one-dimensional stationary Schroedinger
equation in a random delta-correlated potential. The ergodic properties of the
dispersion process are investigated by proving that its generator is
hypoelliptic and using control theory
Physiologically regulated transgenic ABCA1 does not reduce amyloid burden or amyloid‐beta peptide levels in vivo
J Lipid Res. 2007 Apr;48(4):914-23. Epub 2007 Jan 18.
Physiologically regulated transgenic ABCA1 does not reduce amyloid burden or amyloid-beta peptide levels in vivo.
Hirsch-Reinshagen V, Chan JY, Wilkinson A, Tanaka T, Fan J, Ou G, Maia LF, Singaraja RR, Hayden MR, Wellington CL.
Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada.
Abstract
ABCA1-deficient mice have low levels of poorly lipidated apolipoprotein E (apoE) and exhibit increased amyloid load. To test whether excess ABCA1 protects from amyloid deposition, we crossed APP/PS1 mice to ABCA1 bacterial artificial chromosome (BAC) transgenic mice. Compared with wild-type animals, the ABCA1 BAC led to a 50% increase in cortical ABCA1 protein and a 15% increase in apoE abundance, demonstrating that this BAC supports modest ABCA1 overexpression in brain. However, this was observed only in animals that do not deposit amyloid. Comparison of ABCA1/APP/PS1 mice with APP/PS1 controls revealed no differences in levels of brain ABCA1 protein, amyloid, Abeta, or apoE, despite clear retention of ABCA1 overexpression in the livers of these animals. To further investigate ABCA1 expression in the amyloid-containing brain, we then compared ABCA1 mRNA and protein levels in young and aged cortex and cerebellum of APP/PS1 and ABCA1/APP/PS1 animals. Compared with APP/PS1 controls, aged ABCA1/APP/PS1 mice exhibited increased ABCA1 mRNA, but not protein, selectively in cortex. Additionally, ABCA1 mRNA levels were not increased before amyloid deposition but were induced only in the presence of extensive Abeta and amyloid levels. These data suggest that an induction of ABCA1 expression may be associated with late-stage Alzheimer's neuropathology.
PMID: 17235115 [PubMed - indexed for MEDLINE
A qualitative study of a sample of women participating in an Australian randomised controlled trial of intrapartum fetal surveillance
Background: The STan Australian Randomised controlled Trial (START), the first of its kind in Australia, compares two techniques of intrapartum fetal surveillance (cardiotocographic electronic fetal monitoring (CTG) plus analysis of the ST segment of the fetal electrocardiogram (STan + CTG) with CTG alone) with the aim of reducing unnecessary obstetric intervention. It is also the first comprehensive intrapartum fetal surveillance (IFS) trial worldwide, including qualitative examination of psychosocial outcomes and cost- effectiveness. In evaluating and implementing healthcare interventions, the perspectives and experiences of individuals directly receiving them is an integral part of a comprehensive assessment. Furthermore, the added value of using qualitative research alongside randomised controlled trials (RCTs) is becoming widely acknowledged. Objective: This study aimed to examine women’s experiences with the type of IFS they received in the START trial. Methods: Using a qualitative research design, a sample of thirty-two women were interviewed about their experiences with the fetal monitoring they received. Data were analysed using thematic analysis. Findings: Six themes emerged from analysis: reassurance, mobility, discomfort, perception of the fetal Scalp Electrode (FSE), and overall positive experience. Conclusion: Interestingly, it was found that women who had an FSE in the CTG alone arm of the trial reported very similar experiences to women in the STan + CTG arm of the trial. Despite STan and CTG differing clinically, from women’s perspectives, the primary difference between the two techniques was the utilisation (or not) of the FSE. Women were very accepting of STan + CTG as it was perceived and experienced as a more accurate form of monitoring than CTG alone. Findings from this study have sig- nificant implications for health professionals including midwives and obstetricians and implications for standard practice and care. The study has demonstrated the importance and significance of incorporating qualitative enquiry within RCTs.Madeleine Benton, Amy Salter, Bronni Simpson, Chris Wilkinson, Deborah Turnbul
Women’s psychosocial outcomes following an emergency caesarean section: a systematic literature review
BACKGROUND: Given the sudden and unexpected nature of an emergency caesarean section (EmCS) coupled with an increased risk of psychological distress, it is particularly important to understand the psychosocial outcomes for women. The aim of this systematic literature review was to identify, collate and examine the evidence surrounding women’s psychosocial outcomes of EmCS worldwide. METHODS: The electronic databases of EMBASE, PubMed, Scopus, and PsycINFO were searched between November 2017 and March 2018. To ensure articles were reflective of original and recently published research, the search criteria included peer-reviewed research articles published within the last 20 years (1998 to 2018). All study designs were included if they incorporated an examination of women’s psychosocial outcomes after EmCS. Due to inherent heterogeneity of study data, extraction and synthesis of both qualitative and quantitative data pertaining to key psychosocial outcomes were organised into coherent themes and analysis was attempted. RESULTS: In total 17,189 articles were identified. Of these, 208 full text articles were assessed for eligibility. One hundred forty-nine articles were further excluded, resulting in the inclusion of 66 articles in the current systematic literature review. While meta-analyses were not possible due to the nature of the heterogeneity, key psychosocial outcomes identified that were negatively impacted by EmCS included post-traumatic stress, health-related quality of life, experiences, infant-feeding, satisfaction, and self-esteem. Post-traumatic stress was one of the most commonly examined psychosocial outcomes, with a strong consensus that EmCS contributes to both symptoms and diagnosis. CONCLUSIONS: EmCS was found to negatively impact several psychosocial outcomes for women in particular post-traumatic stress. While investment in technologies and clinical practice to minimise the number of EmCSs is crucial, further investigations are needed to develop effective strategies to prepare and support women who experience this type of birth.Madeleine Benton, Amy Salter, Nicole Tape, Chris Wilkinson and Deborah Turnbul
Natural variation in ovule morphology is influenced by multiple tissues and impacts downstream grain development in barley (Hordeum vulgare L.).
The ovule plays a critical role in cereal yield as it is the site of fertilization and the progenitor of the grain. The ovule primordium is generally comprised of three domains, the funiculus, chalaza, and nucellus, which give rise to distinct tissues including the integuments, nucellar projection, and embryo sac. The size and arrangement of these domains varies significantly between model eudicots, such as Arabidopsis thaliana, and agriculturally important monocotyledonous cereal species, such as Hordeum vulgare (barley). However, the amount of variation in ovule development among genotypes of a single species, and its functional significance, remains unclear. To address this, wholemount clearing was used to examine the details of ovule development in barley. Nine sporophytic and gametophytic features were examined at ovule maturity in a panel of 150 European two-row spring barley genotypes, and compared with grain traits from the preceding and same generation. Correlations were identified between ovule traits and features of grain they produced, which in general highlighted a negative correlation between nucellus area, ovule area, and grain weight. We speculate that the amount of ovule tissue, particularly the size of the nucellus, may affect the timing of maternal resource allocation to the fertilized embryo sac, thereby influencing subsequent grain development.Laura G. Wilkinson, Xiujuan Yang, Rachel A. Burton, Tobias Würschum and Matthew R. Tucke
The effect of dietary calcium inclusion on broiler gastrointestinal pH: quantification and method optimization
There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed one of two experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d post hatch. Dietary Ca content had no significant effect on in situ pH, but it contributed towards variance in ex situ pH of both gizzard and duodenum digesta
Ovule cell wall composition is a maternal determinant of grain size in barley
OnlinePublIn cereal species, seed and grain size is influenced by growth of the ovule integuments (seed coat), the spikelet hull (lemma and palea) and the filial endosperm. It has remained unclear whether a highly conserved ovule tissue, the nucellus, has any impact on grain size. Immunolabelling revealed that the barley nucellus comprises two distinct cell types that differ in terms of cell wall homogalacturonan (HG) accumulation. Transcriptional profiling of the nucellus identified two pectin methylesterase genes, OVULE PECTIN MODIFIER 1 (OPM1) and OPM2, which are expressed in the ovule but absent from the seed. Ovules from an opm1 opm2 mutant, and plants expressing an ovule-specific pectin methylesterase inhibitor (PMEI), exhibit reduced HG accumulation. This results in changes to ovule cell size and shape, and ovules that are longer than wild-type controls. At grain maturity, this is manifested as significantly longer grain. These findings indicate that cell wall composition during ovule development acts to limit ovule and seed growth. The investigation of ovule PME and PMEI activity reveals an unexpected role of maternal tissues in controlling grain growth prior to fertilisation, one that has been lacking from models exploring improvements in grain size.Xiujuan Yang, Laura G. Wilkinson, Matthew K. Aubert, Kelly Houston, Neil J. Shirley, and Matthew R. Tucke
A comparison of comorbidity measures for predicting mortality after elective hip and knee replacement : a cohort study of data from the National Joint Registry in England and Wales
Background
The risk of mortality following elective total hip (THR) and knee replacements (KR) may be influenced by patients’ pre-existing comorbidities. There are a variety of scores derived from individual comorbidities that can be used in an attempt to quantify this. The aims of this study were to a) identify which comorbidity score best predicts risk of mortality within 90 days or b) determine which comorbidity score best predicts risk of mortality at other relevant timepoints (30, 45, 120 and 365 days).
Patients and methods
We linked data from the National Joint Registry (NJR) on primary elective hip and knee replacements performed between 2011–2015 with pre-existing conditions recorded in the Hospital Episodes Statistics. We derived comorbidity scores (Charlson Comorbidity Index—CCI, Elixhauser, Hospital Frailty Risk Score—HFRS). We used binary logistic regression models of all-cause mortality within 90-days and within 30, 45, 120 and 365-days of the primary operation using, adjusted for age and gender. We compared the performance of these models in predicting all-cause mortality using the area under the Receiver-operator characteristics curve (AUROC) and the Index of Prediction Accuracy (IPA).
Results
We included 276,594 elective primary THRs and 338,287 elective primary KRs for any indication. Mortality within 90-days was 0.34% (N = 939) after THR and 0.26% (N = 865) after KR. The AUROC for the CCI and Elixhauser scores in models of mortality ranged from 0.78–0.81 after THR and KR, which slightly outperformed models with ASA grade (AUROC = 0.77–0.78). HFRS performed similarly to ASA grade (AUROC = 0.76–0.78). The inclusion of comorbidities prior to the primary operation offers no improvement beyond models with comorbidities at the time of the primary. The discriminative ability of all prediction models was best for mortality within 30 days and worst for mortality within 365 days.
Conclusions
Comorbidity scores add little improvement beyond simpler models with age, gender and ASA grade for predicting mortality within one year after elective hip or knee replacement. The additional patient-specific information required to construct comorbidity scores must be balanced against their prediction gain when considering their utility
Obesity and revision surgery, mortality, and patient-reported outcomes after primary knee replacement surgery in the National Joint Registry : a UK cohort study
BACKGROUND: One in 10 people in the United Kingdom will need a total knee replacement (TKR) during their lifetime. Access to this life-changing operation has recently been restricted based on body mass index (BMI) due to belief that high BMI may lead to poorer outcomes. We investigated the associations between BMI and revision surgery, mortality, and pain/function using what we believe to be the world's largest joint replacement registry. METHODS AND FINDINGS: We analysed 493,710 TKRs in the National Joint Registry (NJR) for England, Wales, Northern Ireland, and the Isle of Man from 2005 to 2016 to investigate 90-day mortality and 10-year cumulative revision. Hospital Episodes Statistics (HES) and Patient Reported Outcome Measures (PROMs) databases were linked to the NJR to investigate change in Oxford Knee Score (OKS) 6 months postoperatively. After adjustment for age, sex, American Society of Anaesthesiologists (ASA) grade, indication for operation, year of primary TKR, and fixation type, patients with high BMI were more likely to undergo revision surgery within 10 years compared to those with "normal" BMI (obese class II hazard ratio (HR) 1.21, 95% CI: 1.10, 1.32 (p < 0.001) and obese class III HR 1.13, 95% CI: 1.02, 1.26 (p = 0.026)). All BMI classes had revision estimates within the recognised 10-year benchmark of 5%. Overweight and obese class I patients had lower mortality than patients with "normal" BMI (HR 0.76, 95% CI: 0.65, 0.90 (p = 0.001) and HR 0.69, 95% CI: 0.58, 0.82 (p < 0.001)). All BMI categories saw absolute increases in OKS after 6 months (range 18-20 points). The relative improvement in OKS was lower in overweight and obese patients than those with "normal" BMI, but the difference was below the minimal detectable change (MDC; 4 points). The main limitations were missing BMI particularly in the early years of data collection and a potential selection bias effect of surgeons selecting the fitter patients with raised BMI for surgery. CONCLUSIONS: Given revision estimates in all BMI groups below the recognised threshold, no evidence of increased mortality, and difference in change in OKS below the MDC, this large national registry shows no evidence of poorer outcomes in patients with high BMI. This study does not support rationing of TKR based on increased BMI
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