3,118 research outputs found

    Spanning with Zero-Price Investment Assets

    Get PDF
    Regression-based testing techniques has long been used to quantify whether the efficient frontier of a set of assets spans the frontier of a larger collection of investments. This work derives regression-based spanning tests for the case in which the investment possibilities set contains, or is constituted by, zero-investment assets. An empirical example illustrates that ignoring the zero-cost qualification of these assets might lead to wrong spanning propositions.mean-variance spanning; diversification benefits; portfolio choice; futures markets

    The co-inheritance of alpha-thalassemia and sickle cell anemia is associated with better hematological indices and lower consultations rate in Cameroonian patients and could improve their survival

    Get PDF
    BACKGROUND: Co-inheritance of α-thalassemia was reported to be associated with a delayed age of disease onset among Cameroonian Sickle Cell Anemia (SCA) patients. The present study aimed to explore the correlation between α-thalassemia, hematological indices, and clinical events in these patients. Methods and FINDINGS: We studied 161 Cameroonian SCA patients and 103 controls (59.1% HbAA) with median ages of 17.5 and 23 years. RFLP-PCR was used to confirm SCA genotype and to describe haplotypes in the HBB-like genes cluster. Multiplex Gap-PCR was performed to investigate the 3.7 kb α-globin gene deletions. SNaPshot PCR, capillary electrophoresis and cycle sequencing were used for the genotyping of 10 SNPs in BCL11A , HMIP1/2 , OR51B5/6 and HBG loci, known to influence HbF levels. Generalised linear regression models adjusted for age, sex and SNPs genotypes was used to investigate effects of α-thalassemia on clinical and hematological indices. The median rate of vaso-occlusive painful crisis and hospitalisations was two and one per year, respectively. Stroke was reported in eight cases (7.4%). Benin haplotype was the most prevalent (66.3%; n = 208 chromosomes). Among patients, 37.3% ( n = 60) had at least one 3.7 kb deletion, compared to 10.9% ( n = 6) among HbAA controls (p<0.001). Among patients, the median RBC count increased with the number of 3.7 kb deletions [2.6, 3.0 and 3.4 million/dl, with no, one and two deletions (p = 0.01)]. The median MCV decreased with the number of 3.7 kb deletion [86, 80, and 68fl, with no, one and two deletions (p<0.0001)], as well as median WBC counts [13.2, 10.5 and 9.8×10 9 /L (p<0.0001. The co-inheritance of α-thalassemia was associated with lower consultations rate (p = 0.038). CONCLUSION: The co-inheritance of α-thalassemia and SCA is associated with improved hematological indices, and lower consultations rate in this group of patients. This could possibly improve their survival and explain the higher proportion of α-thalassemia among patients than controls

    Expression and localization of the aryl hydrocarbon receptors and cytochrome P450 1A during early development of Atlantic cod (Gadus morhua)

    Get PDF
    The aryl hydrocarbon receptor (Ahr) is a ligand-activated transcription factor that mediates the toxicity of dioxins and dioxin-like compounds (DLCs) in vertebrates. Two clades of the Ahr family exist in teleosts (Ahr1 and Ahr2), and it has been demonstrated that Ahr2 is the main protein involved in mediating the toxicity of dioxins and DLCs in most teleost species. Recently, we characterized the Atlantic cod (Gadus morhua) Ahr1a and Ahr2a receptors. To further explore a possible subfunction partitioning of Ahr1a and Ahr2a in Atlantic cod we have mapped the expression and localization of ahr1a and ahr2a in early developmental stages. Atlantic cod embryos were continuously exposed in a passive-dosing exposure system to the Ahr agonist, benzo[a]pyrene (B[a]P), from five days post fertilization (dpf) until three days post hatching (dph). Expression of ahr1a, ahr2a, and the Ahr-target genes, cyp1a and ahrrb, was assessed in embryos (8 dpf and 10 dpf) and larvae (3 dph) with quantitative real-time PCR analyses (qPCR), while in situ hybridization was used to assess the localization of expression of ahr1a, ahr2a and cyp1a. Quantitative measurements showed an increased cyp1a expression in B[a]P-exposed samples at all sampling points, and for ahr2a at 10 dpf, confirming the activation of the Ahr-signalling pathway. Furthermore, B[a]P strongly induced ahr2a and cyp1a expression in the cardiovascular system and skin, respectively, of embryos and larvae. Induced expression of both ahr2a and cyp1a was also revealed in the liver of B[a]P-exposed larvae. Our results suggest that Ahr2a is the major subtype involved in mediating responses to B[a]P in early developmental stages of Atlantic cod, which involves transcriptional regulation of biotransformation genes, such as cyp1a. The focused expression of ahr1a in the eye of embryos and larvae, and the presence of ahr2a transcripts in the jaws and fin nodes, further indicate evolved specialized roles of the two Ahrs in ontogenesis.publishedVersio

    SAR1a promoter polymorphisms are not associated with fetal hemoglobin in patients with sickle cell disease from Cameroon

    Get PDF
    Background: Reactivation of adult hemoglobin (HbF) is currently a dominant therapeutic approach to sickle cell disease (SCD). In this study, we have investigated among SCD patients from Cameroon, the association of HbF level and variants in the HU-inducible small guanosine triphosphate-binding protein, secretion-associated and RAS-related (SAR1a) protein, previously shown to be associated with HbF after HU treatment in African American SCD patients. Results: Only patients >5 years old were included; hemoglobin electrophoresis and a full blood count were conducted upon arrival at the hospital. RFLP-PCR was used to describe the HBB gene haplotypes and Gap PCR to investigate the 3.7 kb α-globin gene deletion. The iPLEX Gold Sequenom Mass Genotyping Array and cycle sequencing were used for the genotyping of four selected SNPs in SAR1a (rs2310991; rs4282891; rs76901216 and rs76901220). Genetic analysis was performed using an additive genetic model, under a generalized linear regression framework. 484 patients were studied. No associations were observed between any of the promoter variants and baseline HbF, clinical events or other hematological indices. Conclusion: The results of this study could be explained by possible population-specifcity of some tagging genomic variants associated with HbF production and illustrated the complexity of replicating HbF-promoting variants association results across African populations

    Occupational exposures and small airway obstruction in the UK Biobank Cohort

    Get PDF
    Background Small airways obstruction (SAO) is a key feature of both COPD and asthma, which have been associated with workplace exposures. Whether SAO, which may occur early in the development of obstructive lung disease and without symptoms, also associates with occupational exposures is unknown. Methods Using UK Biobank data, we derived measurements of SAO from the 65 145 participants with high-quality spirometry and lifetime occupational histories. The ALOHA+ Job Exposure Matrix was used to assign lifetime occupational exposures to each participant. The association between SAO and lifetime occupational exposures was evaluated using a logistic regression model adjusted for potential confounders. A second logistic regression model was also run to account for potential co-exposures. Results SAO was present in varying proportions of the population depending on definition used: 5.6% (forced expiratory flow between 25 and 75% of the forced vital capacity (FEF25–75) < lower limit of normal (LLN)) and 21.4% (forced expiratory volume in 3 s (FEV3)/forced expiratory volume in 6 s (FEV6) <LLN). After adjustment for confounders and co-exposures, people in the highest category of exposure to pesticides were significantly more likely to have SAO (FEV3/FEV6 <LLN: OR 1.24, 95% CI 1.06–1.44). The association between pesticides and SAO showed an exposure-response pattern. SAO was also less likely among people in the highest exposure categories of aromatic solvents (FEV3/FEV6 <LLN: OR 0.85, 95% CI 0.73–0.99) and metals (FEV3/FEV6 <LLN: OR 0.77, 95% CI 0.62–0.94). Conclusion Our findings suggest that occupational exposure to pesticides play a role in the SAO. However, further work is needed to determine causality, and identify the specific component(s) responsible and the underlying mechanisms involved

    Clinical characteristics and risk factors of relative systemic hypertension and hypertension among sickle cell patients in Cameroon

    Get PDF
    Increased blood pressure (BP) has been associated with higher risk of stroke and mortality in Sickle Cell Disease (SCD). We investigated risk factors associated with Relative Systemic Hypertension (RSH) or systemic hypertension in SCD patients in Cameroon. Using R, Multivariate multinomial logistic regression modeling was used to examine the effects of the demographic, anthropometric, clinical, and laboratory factors to determine risk factors. A total of 815 individuals with SCD, including 380 (46.6%) males were analyzed. At baseline, the median age [interquartile range] was 18.0 [12.0–25.0] years, ranging from 3 to 66 years. Approximately three-quarters of the patients (n = 645; 79.1%) had normal BP, 151 (18.5%) had RSH and 19 (2.3%) had hypertension. Age (P &lt; 0.001) and gender (P = 0.022) were significantly different across the BP categories. Weight (P &lt; 0.001), height (P &lt; 0.001), BMI (P &lt; 0.001), pulse pressure (P = 0.020), history of stroke (P = 0.012), hemoglobin level (P = 0.002), red blood cell count (P = 0.031), creatinine (P &lt; 0.001), and (estimated glomerular filtration rate) eGFR (P = 0.002) was also significantly different across the three BP categories. After adjustment, the significantly associated factors of RSH in the SCD patients were age [OR = 1.03, (95% CI = 1.01–1.06), P &lt; 0.010], male gender [OR = 1.54, (95% CI = 1.04–2.27), P = 0.029], BMI [OR = 1.10, (95% CI = 1.04–1.17), P = 0.001]. After adjustment, the independent variables significantly associated factors of Hypertension in the SCD patients were age [OR = 1.05, (95% CI = 1.01–1.10), P = 0.034], male gender [OR = 3.31, (95% CI = 1.04–10.52), P = 0.042], BMI [OR = 1.14, (95% CI = 1.01–1.29), P = 0.027]. Creatinine was significantly associated with RSH [OR =1.31 (1.05–1.63), P = 0.016]. SCD patients with RSH or hypertension maybe at increased risk of renal dysfunction. We found relatively high prevalence of RSH and hypertension (20.8%) in SCD patients in Cameroon. Tailored Interventions that consider major risk factors (age, gender, and BMI) may lower BP pressure and prevent severe complications

    An RNAi screen of the kinome in epithelial follicle cells of the Drosophila melanogaster ovary reveals genes required for proper germline death and clearance

    Get PDF
    Programmed cell death and cell corpse clearance are an essential part of organismal health and development. Cell corpses are often cleared away by professional phagocytes such as macrophages. However, in certain tissues, neighboring cells known as nonprofessional phagocytes can also carry out clearance functions. Here, we use the Drosophila melanogaster ovary to identify novel genes required for clearance by nonprofessional phagocytes. In the Drosophila ovary, germline cells can die at multiple time points. As death proceeds, the epithelial follicle cells act as phagocytes to facilitate the clearance of these cells. We performed an unbiased kinase screen to identify novel proteins and pathways involved in cell clearance during two death events. Of 224 genes examined, 18 demonstrated severe phenotypes during developmental death and clearance while 12 demonstrated severe phenotypes during starvation-induced cell death and clearance, representing a number of pathways not previously implicated in phagocytosis. Interestingly, it was found that several genes not only affected the clearance process in the phagocytes, but also non-autonomously affected the process by which germline cells died. This kinase screen has revealed new avenues for further exploration and investigation.R01 GM060574 - NIGMS NIH HHS; R35 GM127338 - NIGMS NIH HHS; 5R35GM127338-05 REVISED - NIH/National Institute of General Medical Scienceshttps://academic.oup.com/g3journal/article/11/2/jkaa066/6080751?login=truePublished versio

    Real Life Study of Lenvatinib Therapy for Hepatocellular Carcinoma: RELEVANT Study

    Get PDF
    Introduction: In the REFLECT trial, lenvatinib was found to be noninferior compared to sorafenib in terms of overall survival. Here, we analyze the effects of lenvatinib in the real-life experience of several centers across the world and identify clinical factors that could be significantly associated with survival outcomes. Methods: The study population was derived from retrospectively collected data of HCC patients treated with lenvatinib. The overall cohort included western and eastern populations from 23 center in five countries. Results: We included 1,325 patients with HCC and treated with lenvatinib in our analysis. Median OS was 16.1 months. Overall response rate was 38.5%. Multivariate analysis for OS highlighted that HBsAg positive, NLR &gt;3, and AST &gt;38 were independently associated with poor prognosis in all models. Conversely, NAFLD/NASH-related etiology was independently associated with good prognosis. Median progression-free survival was 6.3 months. Multivariate analysis for progression-free survival revealed that NAFLD/NASH, BCLC, NLR, and AST were independent prognostic factors for progression-free survival. A proportion of 75.2% of patients suffered from at least one adverse effect during the study period. Multivariate analysis exhibited the appearance of decreased appetite grade ≥2 versus grade 0-1 as an independent prognostic factor for worse progression-free survival. 924 patients of 1,325 progressed during lenvatinib (69.7%), and 827 of them had a follow-up over 2 months from the beginning of second-line treatment. From first-line therapy, the longest median OS was obtained with the sequence lenvatinib and immunotherapy (47.0 months), followed by TACE (24.7 months), ramucirumab (21.2 months), sorafenib (15.7 months), regorafenib (12.7 months), and best supportive care (10.8 months). Conclusions: Our study confirms in a large and global population of patients with advanced HCC, not candidates for locoregional treatment the OS reported in the registration study and a high response rate with lenvatinib
    • …
    corecore