111 research outputs found

    Single-step methodology for genomic evaluation in turkeys (Meleagris gallopavo)

    Get PDF
    Genomic information can contribute significantly to the increase in accuracy of genetic predictions compared to using pedigree relationships alone. The main objective of this study was to compare the prediction ability of pedigree-based best linear unbiased prediction (PBLUP) and single-step genomic BLUP (ssGBLUP) models. Turkey records of feed conversion ratio, residual feed intake, body weight, breast meat yield, and walking ability were provided by Hybrid Turkeys, Kitchener, Canada. This data was analyzed using pedigree-based and single-step genomic models. The genomic relationship matrix was calculated either using observed allele frequencies, all allele frequencies equal to 0.5 or with a different scaling. To avoid potential problems with inversion, three different weighting factors were applied to combine the genomic and pedigree matrices. Across the studied traits, ssGBLUP had higher heritability estimates and significantly outperformed PBLUP in terms of accuracy. Walking ability was genetically negatively correlated to body weight and breast meat yield; however, it was not correlated to FCR or RFI. Body weight showed a moderate positive genetic correlation to feed conversion ratio, residual feed intake and breast meat yield. Feed conversion ratio was strongly correlated to residual feed intake (0.68±0.06). There was almost no genetic correlation between breast meat yield and feed efficiency traits. Larger differences in accuracy between PBLUP and ssGBLUP were observed for traits with lower heritability. Results of the three weighting factors showed only slight differences and an increase in accuracy of prediction compared to PBLUP. Slightly different levels of bias were observed across the models, but were higher among the traits; BMY was the only trait that had a regression coefficient higher than 1 (1.38 to 1.41). We show that incorporating genomic information increases the prediction accuracy for preselection of young candidate turkeys for the five traits investigated. Single-step genomic prediction showed substantially higher accuracy estimates than the pedigree-based model, and only slight differences in bias were observed across the alternate models

    Engaging with community researchers for exposure science: lessons learned from a pesticide biomonitoring study

    Get PDF
    A major challenge in biomonitoring studies with members of the general public is ensuring their continued involvement throughout the necessary length of the research. The paper presents evidence on the use of community researchers, recruited from local study areas, as a mechanism for ensuring effective recruitment and retention of farmer and resident participants for a pesticides biomonitoring study. The evidence presented suggests that community researchers' abilities to build and sustain trusting relationships with participants enhanced the rigour of the study as a result of their on-the-ground responsiveness and flexibility resulting in data collection beyond targets expected

    Surgical Treatment of Renal Cell Cancer Liver Metastases: A Population-Based Study

    Get PDF
    Background: To evaluate outcomes of surgical treatment in patients with hepatic metastases from renal-cell carcinoma in the Netherlands, and to identify prognostic factors for survival after resection. Renal-cell carcinoma has an incidence of 2,000 new patients in the Netherlands each year (12.5/100,000 inhabitants). According to literature, half of these patients ultimately develop distant metastases with 20% involvement of the liver. Resection of renal-cell carcinoma liver metastases (RCCLM) is performed in only a minority of patients. Hence, little is known about outcome of resectable RCCLM. Methods: Patients were retrieved from local databases of theNetherlands Task Force for Liver Surgery (14 centers) and from the Dutch collective pathology database. Survival and prognostic factors were determined by Kaplan-Meier analysis and log rank test. Results: Thirty-three patients were identified who underwent resection (n = 29) or local ablation (n = 4) of RCCLM in the Netherlands between 1990 and 2008. These patients comprise 0.5% to 1% of the total population of patients diagnosed with RCCLM in that period. There was no operative mortality. The overall survival at 1, 3, and 5 years was 79, 47, and 43%, respectively. Metachronous metastases (n = 23, P = 0.03) and radical resection (n = 19, P < 0.001) were statistically significant prognosticators of ov

    Regional differences in recombination hotspots between two chicken populations

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Although several genetic linkage maps of the chicken genome have been published, the resolution of these maps is limited and does not allow the precise identification of recombination hotspots. The availability of more than 3.2 million SNPs in the chicken genome and the recent advances in high throughput genotyping techniques enabled us to increase marker density for the construction of a high-resolution linkage map of the chicken genome. This high-resolution linkage map allowed us to study recombination hotspots across the genome between two chicken populations: a purebred broiler line and a broiler × broiler cross. In total, 1,619 animals from the two different broiler populations were genotyped with 17,790 SNPs.</p> <p>Results</p> <p>The resulting linkage map comprises 13,340 SNPs. Although 360 polymorphic SNPs that had not been assigned to a known chromosome on chicken genome build WASHUC2 were included in this study, no new linkage groups were found. The resulting linkage map is composed of 31 linkage groups, with a total length of 3,054 cM for the sex-average map of the combined population. The sex-average linkage map of the purebred broiler line is 686 cM smaller than the linkage map of the broiler × broiler cross.</p> <p>Conclusions</p> <p>In this study, we present a linkage map of the chicken genome at a substantially higher resolution than previously published linkage maps. Regional differences in recombination hotspots between the two mapping populations were observed in several chromosomes near the telomere of the p arm; the sex-specific analysis revealed that these regional differences were mainly caused by female-specific recombination hotspots in the broiler × broiler cross.</p

    Is there a role for CT coronary angiography in patients with symptomatic angina? Effect of coronary calcium score on identification of stenosis

    Get PDF
    Present guidelines discourage the use of CT coronary angiography (CTCA) in symptomatic angina patients. We examined the relation between coronary calcium score (CS) and the performance of CTCA in patients with stable and unstable angina in order to understand under which conditions CTCA might be a gate-keeper to conventional coronary angiography (CCA) in such patients. We included 360 patients between 50 and 70 years old with stable and unstable angina who were clinically referred for CCA irrespective of CS. Patients received CS and CCTA on 64-slice scanners in a multicenter cross-sectional trial. The institutional review board approved the study. Diagnostic performance of CTCA to detect or rule out significant coronary artery disease was calculated on a per patient level in pre-defined CS categories. The prevalence of significant coronary artery disease strongly increased with CS. Negative CTCA were associated with a negative likelihood ratio of <0.1 independent of CS. Positive CTCA was associated with a high positive likelihood ratio of 9.4 if CS was <10. However, for higher CS the positive likelihood ratio never exceeded 3.0 and for CS >400 it decreased to 1.3. In the 62 (17%) patients with CS <10, CTCA reliably identified the 42 (68%) of these patients without significant CAD, at no false negative CTCA scans. In symptomatic angina patients, a negative CTCA reliably excludes significant CAD but the additional value of CTCA decreases sharply with CS >10 and especially with CS >400. In patients with CS <10, CTCA provides excellent diagnostic performance

    Activating mutations of the GNAQ gene: a frequent event in primary melanocytic neoplasms of the central nervous system

    Get PDF
    Primary melanocytic neoplasms of the central nervous system (CNS) are uncommon neoplasms derived from melanocytes that normally can be found in the leptomeninges. They cover a spectrum of malignancy grades ranging from low-grade melanocytomas to lesions of intermediate malignancy and overtly malignant melanomas. Characteristic genetic alterations in this group of neoplasms have not yet been identified. Using direct sequencing, we investigated 19 primary melanocytic lesions of the CNS (12 melanocytomas, 3 intermediate-grade melanocytomas, and 4 melanomas) for hotspot oncogenic mutations commonly found in melanocytic tumors of the skin (BRAF, NRAS, and HRAS genes) and uvea (GNAQ gene). Somatic mutations in the GNAQ gene at codon 209, resulting in constitutive activation of GNAQ, were detected in 7/19 (37%) tumors, including 6/12 melanocytomas, 0/3 intermediate-grade melanocytomas, and 1/4 melanomas. These GNAQ-mutated tumors were predominantly located around the spinal cord (6/7). One melanoma carried a BRAF point mutation that is frequently found in cutaneous melanomas (c.1799 T>A, p.V600E), raising the question whether this is a metastatic rather than a primary tumor. No HRAS or NRAS mutations were detected. We conclude that somatic mutations in the GNAQ gene at codon 209 are a frequent event in primary melanocytic neoplasms of the CNS. This finding provides new insight in the pathogenesis of these lesions and suggests that GNAQ-dependent mitogen-activated kinase signaling is a promising therapeutic target in these tumors. The prognostic and predictive value of GNAQ mutations in primary melanocytic lesions of the CNS needs to be determined in future studies

    The Tilburg double blind randomised controlled trial comparing inguinal hernia repair according to Lichtenstein and the transinguinal preperitoneal technique

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Anterior open treatment of the inguinal hernia with a tension free mesh has reduced the incidence of recurrence and direct postoperative pain. The Lichtenstein procedure rules nowadays as reference technique for hernia treatment. Not recurrences but chronic pain is the main postoperative complication in inguinal hernia repair after Lichtenstein's technique. Preliminary experiences with a soft mesh placed in the preperitoneal space showed good results and less chronic pain.</p> <p>Methods</p> <p>The TULIP is a double-blind randomised controlled trial in which 300 patients will be randomly allocated to anterior inguinal hernia repair according to Lichtenstein or the transinguinal preperitoneal technique with soft mesh. All unilateral primary inguinal hernia patients eligible for operation who meet inclusion criteria will be invited to participate in this trial. The primary endpoint will be direct postoperative- and chronic pain. Secondary endpoints are operation time, postoperative complications, hospital stay, costs, return to daily activities (e.g. work) and recurrence. Both groups will be evaluated.</p> <p>Success rate of hernia repair and complications will be measured as safeguard for quality.</p> <p>To demonstrate that inguinal hernia repair according to the transinguinal preperitoneal (TIPP) technique reduces postoperative pain to <10%, with α = 0,05 and power 80%, a total sample size of 300 patients was calculated.</p> <p>Discussion</p> <p>The TULIP trial is aimed to show a reduction in postoperative chronic pain after anterior hernia repair according to the transinguinal preperitoneal (TIPP) technique, compared to Lichtenstein.</p> <p>In our hypothesis the TIPP technique reduces chronic pain compared to Lichtenstein.</p> <p>Trial registration</p> <p>ISRCTN 93798494</p

    Disulfide-Based Poly(amido amine)s for siRNA Delivery: Effects of Structure on siRNA Complexation, Cellular Uptake, Gene Silencing and Toxicity

    Get PDF
    Purpose\ud \ud RNA interference (RNAi) is a process by which small interfering RNAs (siRNA) induce sequence-specific gene silencing. Therefore, siRNA is an emerging promise as a novel therapeutic. In order to realize the high expectations for therapeutic applications, efficient delivery systems for siRNA are necessary.\ud \ud Methods\ud \ud In this study, a new series of biodegradable poly(amido amine)s with disulfide linkages in the backbone was synthesized out of N,N′-cystaminebisacrylamide (CBA), 4-amino-1-butanol (ABOL) and ethylene diamine (EDA). Effects of different percentages of butanolic side chains and protonatable fragments in the main chain on siRNA complexation, cellular uptake, gene silencing and toxicity were investigated.\ud \ud Results\ud \ud Incorporation of EDA in the polymer resulted in increased siRNA condensation. Efficient siRNA condensation was shown to be necessary for cellular uptake; however, excess of polymer decreased siRNA uptake for polymers with high amounts of EDA. Silencing efficiency did not correlate with uptake, since silencing increased with increasing w/w ratio for all polymers. More than 80% knockdown was found for polyplexes formed with polymers containing 25% or 50% EDA, which was combined with low cytotoxicity.\ud \ud Conclusions\ud \ud Poly(amido amine)s with minor fractions of protonatable fragments in the main chain are promising carriers for delivery of siRNA\u

    Two years after molecular diagnosis of familial hypercholesterolemia: Majority on cholesterol-lowering treatment but a minority reaches treatment goal

    Get PDF
    Background: The risk of premature cardiovascular disease in patients with familial hypercholesterolemia (FH) can be profoundly reduced by cholesterol-lowering therapy, and current guidelines for FH advocate ambitious low-density lipoprotein cholesterol (LDL-C) goals. In the present study, we determined whether these goals are reflected in current clinical practice once FH has been diagnosed. Methodology/Principal Findings: In 2008, we sent questionnaires to all subjects (aged 18-65 years) who were molecularly diagnosed with FH in the year 2006 through the screening program in the Netherlands. Of these 1062 subjects, 781 completed the questionnaire (46% males; mean age: 42±12 years; mean LDL-C at molecular diagnosis (baseline): 4.1±1.3 mmol/L). The number of persons that used cholesterol-lowering therapy increased from 397 (51%) at baseline to 636 (81%) after diagnosis. Mean treated LDL-C levels decreased significantly to 3.2±1.1 mmol/L two years after diagnosis. Only 22% achieved the LDL-C target level of ≤2.5 mmol/L. Conclusions/Significance: The proportion of patients using cholesterol-lowering medication was significantly increased after FH diagnosis through
    corecore