Transferability and Fine Mapping of Type 2 Diabetes Loci in African Americans: The Candidate Gene Association Resource Plus Study

Type 2 diabetes (T2D) disproportionally affects African Americans (AfA) but, to date, genetic variants identified from genome-wide association studies (GWAS) are primarily from European and Asian populations. We examined the single nucleotide polymorphism (SNP) and locus transferability of 40 reported T2D loci in six AfA GWAS consisting of 2,806 T2D case subjects with or without end-stage renal disease and 4,265 control subjects from the Candidate Gene Association Resource Plus Study. Our results revealed that seven index SNPs at the TCF7L2, KLF14, KCNQ1, ADCY5, CDKAL1, JAZF1, and GCKR loci were significantly associated with T2D (P < 0.05). The strongest association was observed at TCF7L2 rs7903146 (odds ratio [OR] 1.30; P = 6.86 × 10⁻⁸). Locus-wide analysis demonstrated significant associations (P_emp < 0.05) at regional best SNPs in the TCF7L2, KLF14, and HMGA2 loci as well as suggestive signals in KCNQ1 after correction for the effective number of SNPs at each locus. Of these loci, the regional best SNPs were in differential linkage disequilibrium (LD) with the index and adjacent SNPs. Our findings suggest that some loci discovered in prior reports affect T2D susceptibility in AfA with similar effect sizes. The reduced and differential LD pattern in AfA compared with European and Asian populations may facilitate fine mapping of causal variants at loci shared across populations.Type 2 diabetes (T2D) is a major public health problem affecting 25.8 million people in the U.S. (1). Marked racial differences in its prevalence have been observed, with African American (AfA) adults >40 years of age having nearly twofold higher prevalence than European Americans (27.1 and 15.5%, respectively) (2). In addition to socioeconomic and behavioral risk factors, genetic factors are likely contributors to T2D risk in AfA (3).Genome-wide association studies (GWAS) for T2D and related traits have successfully identified >50 loci with common genetic variants associated with T2D risk in primarily European-descent populations (4–14) and more recently in East and South Asians (15–21). The reported index single nucleotide polymorphisms (SNPs) at these loci have been replicated in multiple populations (22–24) but less successfully in AfA (25–27). Although differences in environment and lack of study power may partly account for the lack of transferability across ethnicities, differences in linkage disequilibrium (LD) patterns, effect sizes, and risk allele frequency also likely impact the replication of index SNPs. Although the long-range LD in European populations allows for the identification of T2D loci using less dense markers, causal variants are not distinguishable from other nearby SNPs in high LD. This issue prompts the need to examine T2D loci in other populations with different allelic and LD architecture, which may help fine mapping of the underlying functional variants (28).We performed a comprehensive evaluation of the LD region of T2D loci reported in European and Asian GWAS in a meta-analysis of six AfA GWAS. By testing the index and nearby SNPs, we evaluated the transferability of the previously reported loci for T2D association in AfA. We demonstrated that the reduced and differential LD structure in AfA facilitated fine mapping of regions potentially harboring causal variants at some T2D loci.     

动态心电图对体表心电图P-R间期延长的诊断价值

目的 探讨动态心电图对体表心电图P．R间期延长的诊断价值,分析P—R间期延长的临床意义和预后。方法选择2008年1月至2011年8月在昆明医学院第二附属医院住院和门诊心电图有P-R间期延长的患者90例为研究对象．监测其动态心电图。分析P．R间期的变化及阵发性心房颤动、房室结双径路传导、第二度I型房室阻滞、间歇性左右束支阻滞4类心律失常。并且根据P—R间期延长程度分为3组,对比其与上述4类心律失常的关系。结果动态心动图结果中伴发第二度I型房室阻滞2l例（23．33％）、房室结双径路传导17例（18．89％）、间歇性左右束支阻滞9例（10％）、阵发性心房颤动7例（7．78％）。在所有的患者中,P．R间期延长伴发上述4类心律失常发生率为60％。心电图结果中,P-R间期延长50例,显著延长29例,过度延长11例。动态心动图结果中。P。R间期延长32例,显著延长38例,过度延长20例。结论P—R间期延长不应均视为良性和无须干预的心律失常,相反,需要进行进一步动态心动图监测及电生理检查和追踪观察,争取早期发现病变、消除病变,为临床早期诊断、早期治疗提供辅助手段。     

住院患者入院时血糖水平与医疗费用、疾病预后的相关研究

目的探讨住院患者人院时不同血糖水平与住院时间、医疗费用及疾病预后的关系。方法选取2009年11月至2011年7月期间人院的4868例患者,按入院24h内测得的血糖水平分为非高血糖组3429例、高血糖组1439例,后者包括糖尿病和应激性高血糖患者;根据患者年龄分为非老年组（年龄〈60岁）2532例和老年组（年龄≥60岁）2336例;其中278例冠心病患者再分为高血糖组120例和非高血糖组158例。各组间进行有关数据比较。结果高血糖组患者的住院天数、医疗费用和总病死率均显著高于非高血糖组（中位数住院日：15vs10d,P〈0．01;中位数医疗费用：14064．7vs8980．9元,P〈0．01;死亡率：2．92％vs0．61％,P〈0．01）。按年龄分组后,无论是非老年组还是老年组中糖尿病和应激性高血糖患者的医疗费用均明显高于非高血糖患者,住院日明显延长;应激性高血糖患者的医疗费用明显高于糖尿病患者;非老年组中应激性高血糖患者的死亡率明显高于非高血糖患者,但与糖尿病患者相比无明显差异,老年组糖尿病和应激性高血糖患者的死亡率无明显差异,但均明显高于非高血糖患者。冠心病患者中糖尿病和应激性高血糖患者与非高血糖患者的年龄无明显差异,前两组的医疗费用明显高于非高血糖组,住院日更长（分别为14,15和12d）、死亡率更高（分别为6．41％,7．14％和0．63％）。结论入院时高血糖水平预示患者有更高的医疗花费、更长的住院时间和更高的死亡率。     

EphB4 enhances the process of endochondral ossification and inhibits remodeling during bone fracture repair

Previous reports have identified a role for the tyrosine kinase receptor EphB4 and its ligand, ephrinB2, as potential mediators of both bone formation by osteoblasts and bone resorption by osteoclasts. In the present study, we examined the role of EphB4 during bone repair after traumatic injury. We performed femoral fractures with internal fixation in transgenic mice that overexpress EphB4 under the collagen type 1 promoter (Col1‐EphB4) and investigated the bone repair process up to 12 weeks postfracture. The data indicated that Col1‐EphB4 mice exhibited stiffer and stronger bones after fracture compared with wild‐type mice. The fractured bones of Col1‐EphB4 transgenic mice displayed significantly greater tissue and bone volume 2 weeks postfracture compared with that of wild‐type mice. These findings correlated with increased chondrogenesis and mineral formation within the callus site at 2 weeks postfracture, as demonstrated by increased safranin O and von Kossa staining, respectively. Interestingly, Col1‐EphB4 mice were found to possess significantly greater numbers of clonogenic mesenchymal stromal progenitor cells (CFU‐F), with an increased capacity to form mineralized nodules in vitro under osteogenic conditions, when compared with those of the wild‐type control mice. Furthermore, Col1‐EphB4 mice had significantly lower numbers of TRAP‐positive multinucleated osteoclasts within the callus site. Taken together, these observations suggest that EphB4 promotes endochondral ossification while inhibiting osteoclast development during callus formation and may represent a novel drug target for the repair of fractured bones. © 2013 American Society for Bone and Mineral Research.     

Characterisation of exogenous folate transport in Plasmodium falciparum

Folate salvage by Plasmodium falciparum is an important source of key cofactors, but little is known about the underlying mechanism. Using synchronised parasite cultures, we observed that uptake of this dianionic species against the negative-inward electrochemical gradient is highly dependent upon cell-cycle stage, temperature and pH, but not on mono- or divalent metal ions. Energy dependence was tested with different sugars; glucose was necessary for folate import, although fructose was also able to function in this role, unlike sugars that cannot be processed through the glycolytic pathway. Import into both infected erythrocytes and free parasites was strongly inhibited by the anion-channel blockers probenecid and furosemide, which are likely to be acting predominantly on specific folate transporters in both cases. Import was not affected by high concentrations of the antifolate drugs pyrimethamine and sulfadoxine, but was inhibited by the close folate analogue methotrexate. The pH optimum for folate uptake into infected erythrocytes was 6.5-7.0. Dinitrophenol and nigericin, which strongly facilitate the equilibration of H(+) ions across biological membranes and thus abolish or substantially reduce the proton gradient, inhibited folate uptake profoundly. The ATPase inhibitor concanamycin A also greatly reduced folate uptake, further demonstrating a link to ATP-powered proton transport. These data strongly suggest that the principal folate uptake pathway in P. falciparum is specific, highly regulated, dependent upon the proton gradient across the parasite plasma membrane, and is likely to be mediated by one or more proton symporters.     

Pneumomediastinum and retroperitoneal air after removal of papillomas with the microdebrider and jet ventilation

OBJECTIVE: To discuss the complication of pneumothorax from alveolar rupture after transtracheal high-frequency jet ventilation and to present a case of pneumothorax, pneumomediastinum and pneumoperitoneum after jet ventilation coupled with use of the microdebrider. METHOD: Detailed case report. RESULTS: Unilateral pnuemothorax, subcutaneous emphysema, pneumomediastinum and retroperitoneal air discovered after jet ventilation for removal of airway papillomas resolved with conservative management. DISCUSSION: We discuss the difference between the respective patterns of air seepage in a peripheral alveolar injury versus a probable microperforation in the trachea. We also review the epidemiology of this rare disorder and its incidence in the African-American community. CONCLUSION: The recurrent nature of this disorder mandates multiple surgical procedures. Great care must be taken to eradicate disease and avoid complications. Pneumomediastinum in this setting can be managed conservatively.     

Prospective Longitudinal Substance Use Patterns in Patients Preparing for Hepatitis C Treatment

Objectives: This study prospectively examined the independent courses of alcohol, drugs, and smoking over 18 months in 154 patients preparing for hepatitis C virus (HCV) treatment in relation to functioning, negative coping, and satisfaction with quality of life in data collected from a randomized controlled trial of multiple-family group psychoeducation for patients preparing for HCV treatment. Patients with HCV who had consistent abstinence, consistent use, or achievement of abstinence after study entry were examined for outcomes pertaining to functioning in the context of HCV, negative coping, and satisfaction with quality of life. Methods: Of 309 patients considering treatment for HCV recruited from outpatient clinics at two major university medical centers and a Veterans Affairs medical center for a randomized controlled trial of a psychoeducation intervention, 154 completed baseline, 6-month, and 18-month assessments. The assessments included structured diagnostic interviews; questionnaires examining functioning, coping, and satisfaction with quality of life; medical record review; and urine testing for substances of abuse. For these analyses, substance use patterns were determined as consistent abstinence, consistent use, and achieving abstinence after study entry for alcohol and drug use and smoking. Results: The entire sample generally improved in all of these three outcomes over the course of the study. The course of alcohol, drugs, and smoking predicted HCV-related functioning, negative coping, and satisfaction with quality-of-life outcomes over 18 months. Three specific patterns of use (consistent abstinence, consistent use, and achievement of abstinence after study entry) of these substances diverged in association with outcomes related to functioning, negative coping, and satisfaction with quality of life, not only across trajectories over time within substance types but also among types of substances. Conclusions: This study's finding that different substances were associated with distinct clinical outcomes suggests the need to conceptually unbundle different types of substances in managing HCV. Future research is needed to examine the clinical utility of further unbundling these substances and also to further investigate effects of various amounts of use of these substances.     

Opposing activities of two novel members of the IL-1 ligand family regulate skin inflammation

The interleukin (IL)-1 family members IL-1α, -1β, and -18 are potent inflammatory cytokines whose activities are dependent on heterodimeric receptors of the IL-1R superfamily, and which are regulated by soluble antagonists. Recently, several new IL-1 family members have been identified. To determine the role of one of these family members in the skin, transgenic mice expressing IL1F6 in basal keratinocytes were generated. IL1F6 transgenic mice exhibit skin abnormalities that are dependent on IL-1Rrp2 and IL-1RAcP, which are two members of the IL-1R family. The skin phenotype is characterized by acanthosis, hyperkeratosis, the presence of a mixed inflammatory cell infiltrate, and increased cytokine and chemokine expression. Strikingly, the combination of the IL-1F6 transgene with an IL1F5 deficiency results in exacerbation of the skin phenotype, demonstrating that IL-1F5 has antagonistic activity in vivo. Skin from IL1F6 transgenic, IL1F5^−/− pups contains intracorneal and intraepithelial pustules, nucleated corneocytes, and dilated superficial dermal blood vessels. Additionally, expression of IL1RL2, -1F5, and -1F6 is increased in human psoriatic skin. In summary, dysregulated expression of novel agonistic and antagonistic IL-1 family member ligands can promote cutaneous inflammation, revealing potential novel targets for the treatment of inflammatory skin disorders.