187 research outputs found
Ex vivo culture of adult CD34+ stem cells using functional highly porous polymer scaffolds to establish biomimicry of the bone marrow niche
Haematopoiesis, the process of blood production, occurs from a tiny contingent of haematopoietic stem cells (HSC) in highly specialised three-dimensional niches located within the bone marrow. When haematopoiesis is replicated using in vitro two-dimensional culture, HSCs rapidly differentiate, limiting self-renewal. Emulsion-templated highly porous polyHIPE foam scaffolds were chosen to mimic the honeycomb architecture of human bone. The unmodified polyHIPE material supports haematopoietic stem and progenitor cell (HSPC) culture, with successful culture of erythroid progenitors and neutrophils within the scaffolds. Using erythroid culture methodology, the CD34+ population was maintained for 28 days with continual release of erythroid progenitors. These cells are shown to spontaneously repopulate the scaffolds, and the accumulated egress can be expanded and grown at large scale to reticulocytes. We next show that the polyHIPE scaffolds can be successfully functionalised using activated BM(PEG)2 (1,8-bismaleimido-diethyleneglycol) and then a Jagged-1 peptide attached in an attempt to facilitate notch signalling. Although Jagged-1 peptide had no detectable effect, the BM(PEG)2 alone significantly increased cell egress when compared to controls, without depleting the scaffold population. This work highlights polyHIPE as a novel functionalisable material for mimicking the bone marrow, and also that PEG can influence HSPC behaviour within scaffolds
Follicle-stimulating hormone in postmenopausal women living with HIV: a prevalence study
OBJECTIVES: We examined follicle-stimulating hormone (FSH) levels in women living with HIV aged > 45 reporting ≥ 12 months' amenorrhoea, and investigated correlation with menopausal symptoms. METHODS: A cross-sectional substudy of 85 women from the Positive Transitions through the Menopause (PRIME) Study who reported irregular periods at entry into the PRIME Study and ≥ 12 months' amenorrhoea at recruitment into this substudy. Serum FSH was supplemented with clinical data and menopausal symptom assessment. Serum FSH > 30 mIU/mL was defined as consistent with postmenopausal status. Associations between FSH and menopausal symptom severity were assessed using Pearson's correlation and the Kruskal-Wallis test. RESULTS: Median age was 53 years [interquartile range (IQR): 51-55]; all were on antiretroviral therapy, three-quarters (n = 65) had a CD4 T-cell count > 500 cells/μL and 91.8% (n = 78) had an HIV viral load (VL) 30 mIU/mL (40.8 vs. 30.5 kg/m2 ). Over a quarter (28.2%) reported severe menopausal symptoms, with no correlation between FSH and severity of menopausal symptoms (p = 0.21), or hot flushes (p = 0.37). CONCLUSIONS: Four women in this small substudy had low FSH despite being amenorrhoeic; all had BMI ≥ 35 kg/m2 . We found that 95% of women with HIV aged > 45 years reporting ≥ 12 months' amenorrhoea had elevated FSH, suggesting that menopausal status can be ascertained from menstrual history alone in this group
That was a great commercial, but what were they selling?: Effects of violence and sex on memory for products in televisioncommercials
College students (N = 324) watched a television program containing violence, sex, or no violence or sex. Each program contained 3 violent ads, 3 sexual ads, and 3 neutral ads. Participants were less likely to remember the advertised brands when the ads were embedded in a violent or sexual program than when the ads were embedded in a neutral program. Violent ads were the least memorable. This memory impairment occurred for both males and females, regardless of the content of the ads. If advertisers want viewers to remember advertised brands, they should think twice about sponsoring programs containing violence and sex. © 2007 Copyright the Authors; Journal compilation © 2007 Blackwell Publishing, Inc
Vitamin K supplementation to improve vascular stiffness in CKD:The K4Kidneys randomized controlled trial
BACKGROUND:Vascular calcification, a risk factor for cardiovascular disease, is common among patients with CKD and is an independent contributor to increased vascular stiffness and vascular risk in this patient group. Vitamin K is a cofactor for proteins involved in prevention of vascular calcification. Whether or not vitamin K supplementation could improve arterial stiffness in patients with CKD is unknown. METHODS:To determine if vitamin K supplementation might improve arterial stiffness in patients in CKD, we conducted a parallel-group, double-blind, randomized trial in participants aged 18 or older with CKD stage 3b or 4 (eGFR 15-45 ml/min per 1.73 m2). We randomly assigned participants to receive 400 μg oral vitamin K2 or matching placebo once daily for a year. The primary outcome was the adjusted between-group difference in carotid-femoral pulse wave velocity at 12 months. Secondary outcomes included augmentation index, abdominal aortic calcification, BP, physical function, and blood markers of mineral metabolism and vascular health. We also updated a recently published meta-analysis of trials to include the findings of this study. RESULTS:We included 159 randomized participants in the modified intention-to-treat analysis, with 80 allocated to receive vitamin K and 79 to receive placebo. Mean age was 66 years, 62 (39%) were female, and 87 (55%) had CKD stage 4. We found no differences in pulse wave velocity at 12 months, augmentation index at 12 months, BP, B-type natriuretic peptide, or physical function. The updated meta-analysis showed no effect of vitamin K supplementation on vascular stiffness or vascular calcification measures. CONCLUSIONS:Vitamin K2 supplementation did not improve vascular stiffness or other measures of vascular health in this trial involving individuals with CKD. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER:Vitamin K therapy to improve vascular health in patients with chronic kidney disease, ISRCTN21444964 (www.isrctn.com)
The Leydig cell biomarker INSL3 as a predictor of age-related morbidity: Findings from the EMAS cohort
Background: Insulin-like peptide 3 (INSL3) is a constitutive hormone secreted in men by the mature Leydig cells of the testes. It is an accurate biomarker for Leydig cell functional capacity, reflecting their total cell number and differentiation status.
Objectives: To determine the ability of INSL3 to predict hypogonadism and age-related morbidity using the EMAS cohort of older community-dwelling men.
Materials & methods: Circulating INSL3 was assessed in the EMAS cohort and its cross-sectional and longitudinal relationships to hypogonadism, here defined by testosterone (T) <10.5nmol/l, and a range of age-related morbidities determined by correlation and regression analysis.
Results & discussion: While INSL3 is an accurate measure of primary hypogonadism, secondary and compensated hypogonadism also indicate reduced levels of INSL3, implying that testicular hypogonadism does not improve even when LH levels are increased, and that ageing-related hypogonadism may combine both primary and secondary features. Unadjusted, serum INSL3, like calculated free testosterone (cFT), LH, or the T/LH ratio reflects hypogonadal status and is associated with reduced sexual function, bone mineral density, and physical activity, as well as increased occurrence of hypertension, cardiovascular disease, cancer, and diabetes. Using multiple regression analysis to adjust for a range of hormonal, anthropometric, and lifestyle factors, this relationship is lost for all morbidities, except for reduced bone mineral density, implying that INSL3 and/or its specific receptor, RXFP2, may be causally involved in promoting healthy bone metabolism. Elevated INSL3 also associates with hypertension and cardiovascular disease. When unadjusted, INSL3 in phase 1 of the EMAS study was assessed for its association with morbidity in phase 2 (mean 4.3 years later); INSL3 significantly predicts 7 out of 9 morbidity categories, behaving as well as cFT in this regard. In contrast, total T was predictive in only 3 of the 9 categories.
Conclusion: Together with its low within-individual variance, these findings suggest that assessing INSL3 in men could offer important insight into the later development of disease in the elderly
An Analysis of Vascular Access Thrombosis Events From the Proactive IV irOn Therapy in hemodiALysis Patients Trial
INTRODUCTION:
Treatment of anemia in dialysis patients has been associated with increased risk of vascular access thrombosis (VAT). Proactive IV irOn Therapy in hemodiALysis Patients (PIVOTAL) was a clinical trial of proactive compared with reactive i.v. iron therapy in patients requiring hemodialysis. We analyzed the trial data to determine whether randomized treatment arm, alongside other clinical and laboratory variables, independently associated with VAT.
METHODS:
In PIVOTAL, 2141 adult patients were randomized. The type of vascular access (arteriovenous fistula [AVF], arteriovenous graft [AVG], or central venous catheter [CVC]) was recorded at baseline and every month after randomization. The associations between clinical and laboratory data and first VAT were evaluated in a multivariate analysis.
RESULTS:
A total of 480 (22.4%) participants experienced VAT in a median of 2.1 years of follow-up. In multivariable analyses, treatment arm (proactive vs. reactive) was not an independent predictor of VAT (hazard ratio [HR] 1.13, P = 0.18). Diabetic kidney disease (HR 1.45, P < 0.001), AVG use (HR 2.29, P < 0.001), digoxin use (HR 2.48, P < 0.001), diuretic use (HR 1.25, P = 0.02), female sex (HR 1.33, P = 0.002), and previous/current smoker (HR 1.47, P = 0.004) were independently associated with a higher risk of VAT. Angiotensin receptor blocker (ARB) use (HR 0.66, P = 0.01) was independently associated with a lower risk of VAT.
CONCLUSION:
In PIVOTAL, VAT occurred in nearly 1 quarter of participants in a median of just >2 years. In this post hoc analysis, randomization to proactive i.v. iron treatment arms did not increase the risk of VAT
The pangenome of an agronomically important crop plant Brassica oleracea
There is an increasing awareness that as a result of structural variation, a reference sequence representing a genome of a single individual is unable to capture all of the gene repertoire found in the species. A large number of genes affected by presence/absence and copy number variation suggest that it may contribute to phenotypic and agronomic trait diversity. Here we show by analysis of the Brassica oleracea pangenome that nearly 20% of genes are affected by presence/absence variation. Several genes displaying presence/absence variation are annotated with functions related to major agronomic traits, including disease resistance, flowering time, glucosinolate metabolism and vitamin biosynthesis
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