Whole-genome sequencing of six dog breeds from continuous altitudes reveals adaptation to high-altitude hypoxia

The hypoxic environment imposes severe selective pressure on species living at high altitude. To understand the genetic bases of adaptation to high altitude in dogs, we performed whole-genome sequencing of 60 dogs including five breeds living at continuous altitudes along the Tibetan Plateau from 800 to 5100 m as well as one European breed. More than 150× sequencing coverage for each breed provides us with a comprehensive assessment of the genetic polymorphisms of the dogs, including Tibetan Mastiffs. Comparison of the breeds from different altitudes reveals strong signals of population differentiation at the locus of hypoxia-related genes including endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1) and beta hemoglobin cluster. Notably, four novel nonsynonymous mutations specific to high-altitude dogs are identified at EPAS1, one of which occurred at a quite conserved site in the PAS domain. The association testing between EPAS1 genotypes and blood-related phenotypes on additional high-altitude dogs reveals that the homozygous mutation is associated with decreased blood flow resistance, which may help to improve hemorheologic fitness. Interestingly, EPAS1 was also identified as a selective target in Tibetan highlanders, though no amino acid changes were found. Thus, our results not only indicate parallel evolution of humans and dogs in adaptation to high-altitude hypoxia, but also provide a new opportunity to study the role of EPAS1 in the adaptive processes.The mechanisms of organismal adaptation to high-altitude hypoxia are of great interest during recent years. Highland wild animals have a long life history at high altitude, and the whole genomes of yak (descendants of wild yak) (Qiu et al. 2012), Tibetan antelope (Ge et al. 2013), snow leopard (Cho et al. 2013), and wild boar (Li et al. 2013) have been sequenced. In contrast, the human settlement history on highland is rather short, which dates from ∼25,000 yr ago (Zhao et al. 2009). Whole-genome genotyping and re-sequencing have been performed for three typical highland populations including Tibetans (Beall et al. 2010; Bigham et al. 2010; Simonson et al. 2010; Yi et al. 2010; Peng et al. 2011; Xu et al. 2011), Andeans (Bigham et al. 2009, 2010), and Ethiopians (Alkorta-Aranburu et al. 2012; Scheinfeldt et al. 2012).The increased oxygen uptake and delivery are physiological hallmarks of high-altitude adaptation. On one hand, the capacity of oxygen uptake is determined by hemoglobin concentration and oxygen affinity. For example, the Andean highlanders display a high level of hemoglobin concentration (Beall et al. 2002; Beall 2007). The high oxygen affinity of hemoglobin is found in many highland animals such as yak (Weber et al. 1988), alpaca (Piccinini et al. 1990), deer mice (Storz et al. 2007; Storz et al. 2009), bar-headed goose (Zhang et al. 1996; Liang et al. 2001), and Andean goose (Jessen et al. 1991). On the other hand, the rate of oxygen delivery is determined by blood flow. For example, although Tibetans maintain a nearly normal level of hemoglobin concentration and a low level of oxygen saturation, they display a high level of blood flow, resulting in the increase of oxygen delivery (Beall et al. 2001; Erzurum et al. 2007).Whole-genome scans revealed that positive selection for human high-altitude adaptation occurred in the hypoxia-inducible factor (HIF) pathway (Bigham et al. 2009; Beall et al. 2010; Bigham et al. 2010; Simonson et al. 2010; Yi et al. 2010; Peng et al. 2011; Xu et al. 2011; Alkorta-Aranburu et al. 2012; Scheinfeldt et al. 2012), which regulates genes associated with blood physiology. In addition, metabolic pathways may also be involved in the adaptive process of yak (Qiu et al. 2012) and Tibetan antelope (Ge et al. 2013).Although a lot of studies focused on wildlife and human highlanders, no research was performed on domesticated animals that migrated to the plateau with humans, which represent an adaptation pattern on a short evolutionary time scale of thousands of years. For example, the Tibetan Mastiff is a native dog living in the Tibetan Plateau with an altitude of 3000–6000 m. It is also an ancient dog in the world (Li and Zhang 2012). However, the genetic and physiological mechanisms of its adaptation to high-altitude environments remain elusive.In this study, we sampled five dog breeds including the Tibetan Mastiff from continuous altitudes along the Ancient Tea Horse Road in southwestern China as well as one European breed. We performed whole-genome sequencing for the dogs and identified candidate genes for high-altitude adaptation using selective sweep mapping. We also measured the hematologic and hemorheologic parameters of the dogs and tested the association between the candidate alleles and blood physiology.     

自发性气胸胸腔镜术后复发情况和影响因素分析

目的分析自发性气胸患者胸腔镜术后复发现状和影响因素。方法选取我院胸外科2009年3月至2011年3月收治的218例自发性气胸胸腔镜术后患者为研究对象,采用自编问卷对自发性气胸患者胸腔镜术后情况进行调查,应用SPSS 19.0统计软件进行描述性统计和二分类Logistic回归分析并找出其复发的影响因素。结果自发性气胸患者胸腔镜术后复发率为5.05%(11/218),多因素Logistic回归分析结果示复发性气胸(OR=2.432,P=0.000)和多发肺大疱(OR=1.918,P=0.000)是自发性气胸电视胸腔镜手术后复发的危险因素。结论自发性气胸胸腔镜术后患者复发率较高,应加强复发性气胸和多发肺大疱患者管理,减少其复发,改善患者的预后。     

采用TaqMan MGB探针定量检测HCV 1b基因型C区氨基酸70变异

目的 建立一种定量检测HCV 1b基因型C区氨基酸70位点主要野生株（Arg-CGG,70w）和变异株（GIn-CAG,70M）的方法.方法 设计一对分别针对70 W和70 M的TaqMan MGB探针,建立一种实时逆转录聚合酶链反应定量检测方法.验证方法的敏感性、特异性和准确性.结果 所设计的引物和探针具有良好的特异性,敏感性可达5拷贝/反应.进一步的克隆测序证实了新方法的可靠性.结论 建立了一套HCV 1b亚型C区氨基酸70变异的定量检测系统,具有较高的敏感性、特异性和准确性,为研究70 W和70 M在抗病毒治疗中的动态变化提供了技术手段.     

初探循证心理治疗在团体心理辅导中的应用

团体心理辅导是高校的心理健康教育的主要形式之一,但其在考虑团体成员的特征、文化、偏好,团体领导者素质,团体心理辅导方案的监督与评估等方面存在一定的局限性。本文尝试着用循证心理治疗的理念观对团体心理辅导中的成员甄别、领导者选择、实施过程监督等方面进行研究,从而完善团体心理辅导的可操作性和加强团体辅导效果。     

Ultrasensitive detection of uric acid in serum of patients with gout by a new assay based on Pt@Ag nanoflowers

A ultrasensitive assay for the determination of uric acid (UA) based on Pt@Ag nanoflowers (Pt@Ag NFs) was constructed. H₂O₂ was formed by the reaction of uricase and UA and produced the hydroxyl radical (˙OH). The system was catalyzed by Pt@Ag NFs to change the color of 3,3′,5,5′-tetramethylbenzidine (TMB) from colorless to blue, and the morphology and chemical properties of Pt@Ag NFs were characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. Under the optimized conditions, a linear relationship between the absorbance and UA concentration was in the range of 0.5–150 μM (R² = 0.995) with a limit of detection of 0.3 μM (S/N = 3). The method can be applied to detection of UA in actual samples with satisfactory results. The proposed assay was successfully applied to the detection of UA in human serum with recoveries over 96.8%. Thus, these results imply that the UA assay provides an effective tool in fast clinical analysis of gout.

A ultrasensitive assay for the determination of uric acid (UA) based on Pt@Ag nanoflowers (Pt@Ag NFs) was constructed.     

Risk factors for ventilator-associated pneumonia in the neonatal intensive care unit: a meta-analysis of observational studies

Ventilator-associated pneumonia (VAP) is a common and serious problem among mechanically ventilated patients in intensive care units (ICU), especially for the newborn. However, limited literatures have been reviewed to synthesize the finding of previous papers to investigate the risk factors for VAP although it has been a serious complication of mechanical ventilation (MV) with a high morbidity and mortality in the newborn. We performed this meta-analysis to extend previous knowledge for developing VAP prevention strategies by identifying the potential risk factors related to VAP in the neonatal intensive care unit (NICU). The relevant literatures published up to July 2013 were searched in the databases of PubMed, Cochrane Central Register of Controlled Trials, Embase, and Web of Science. Three reviewers screened those literatures and extracted data according to the inclusion and exclusion criteria independently. A total of eight studies including 370 cases and 1,071 controls were identified. Ten risk factors were found to be related to neonatal VAP which were listed as follows in order by odds ratios (ORs): length of stay in NICU (OR 23.45), reintubation (OR 9.18), enteral feeding (OR 5.59), mechanical ventilation (OR 4.04), transfusion (OR 3.32), low birth weight (OR 3.16), premature infants (OR 2.66), parenteral nutrition (OR 2.30), bronchopulmonary dysplasia (OR 2.21), and tracheal intubation (OR 1.12). Conclusion: We identified ten variables as independent risk factors for the development of VAP: length of stay in NICU, reintubation, enteral feeding, mechanical ventilation, transfusion, low birth weight, premature infants, parenteral nutrition, bronchopulmonary dysplasia, and tracheal intubation. Due to several limitations in the present study, further large and well-designed studies are needed to confirm the conclusion.     

Iron phosphide nanoparticles as a pH-responsive T1 contrast agent for magnetic resonance tumor imaging

In this work, the potential of FeP nanoparticles as a pH-responsive T₁ contrast agent was investigated. The FeP nanoparticles have good biocompatibility and can significantly amplify T₁ magnetic resonance signals in response to the acidic microenvironment of solid tumors, holding great promise in serving as an acid-activatable T₁ contrast agent for tumor imaging.

In this work, the potential of FeP nanoparticles as a pH-responsive T₁ contrast agent was investigated.

Magnetic resonance imaging (MRI) is currently one of the most powerful medical imaging techniques due to its noninvasive character, deep tissue penetration, and ability to provide images with excellent anatomical details.^1–3 MRI contrast agents are a group of contrast media that can improve the accuracy and specificity of MRI.^4–6 In general, MRI contrast agents can be divided into T₁ positive contrast agents and T₂ negative contrast agents according to the relaxation processes. T₁ contrast agents shorten the longitudinal relaxation time of water protons, resulting in a brighter signal, while T₂ contrast agents reduce the transverse relaxation time, leading to a darker signal.^7,8 Nanomaterials containing paramagnetic metal ions (e.g., Gd³⁺, Mn²⁺, and Fe³⁺) have been widely used as T₁ MRI contrast agents.^9–14 On the other hand, magnetic nanoparticles with high saturation magnetization are the most commonly used as T₂ contrast agents because they can generate a local magnetic field in the presence of the external magnetic field to accelerate the dephasing of surrounding water protons.^15–17The exploitation of highly specific and sensitive imaging contrast agents is of great importance for precise disease diagnosis.¹⁸ Activatable imaging contrast agents that can respond to biological stimulis (e.g., pH, redox potential, and enzyme) to produce contrast signals, have emerged as the next generation of molecular imaging probes.^19–22 They can minimize the signal from nontarget background, therefore greatly improve the target-to-background ratio. Conventional T₁ contrast agents such as Gd₂O₃ nanoparticles and MnO nanoparticles have been demonstrated that can afford effective T₁ shortening effect to improve the visibility. However, these contrast agents continuously emit signals are “always on”, which fail to response to pathological parameters and hence lack in specificity and sensitivity. Activatable MRI contrast agents that only generate signals in response to a certain stimuli (e.g., physiological difference in pH in tumor microenvironment) thus are highly desirable, because they not only greatly enhance the specificity and sensitivity of disease diagnosis, but also potentially allow MRI to monitor biological processes.^23–25 Herein, we report a novel pH-activatable T₁ contrast agent based on FeP nanoparticles. We found that the as-synthesized FeP nanoparticles can respond to the acidic microenvironment of solid tumor to produce significant T₁ contrast enhancement by releasing paramagnetic Fe ions. Furthermore, both in vitro and in vivo investigations indicate that the FeP nanoparticles have good biocompatibility that show no obvious cytotoxicity and harmful effects. Therefore, the FeP nanoparticles can potentially serve as an acid-responsive T₁ MRI contrast agent for tumor imaging.     

连续性血液净化与新生儿急性肾损伤

新生儿急性肾损伤（ acute kidney injury,AKI）是新生儿危重症之一,在新生儿重症监护病房中的发生率高达23％,病死率25％～50％。新生儿AKI是指新生儿在低血容量、窒息、休克、缺氧、溶血、低体温等各种不利因素导致肾功能受到损害,出现少尿或无尿、电解质紊乱、酸碱平衡失调及血浆中肾排出的代谢产物（尿素、肌酐等）浓度增高。目前,新生儿AKI暂无有效的防治措施。近年来,随着血液净化技术进步,连续性血液净化（ continuous blood purification,CBP）应用范围已从儿童AKI已发展到新生儿AKI。由于新生儿血液动力学不稳定及血容量小等特点,CBP在新生儿AKI中应用仍然面临诸多问题。该文就新生儿AKI的高危因素、诊断标准、新生儿CBP治疗相关问题等进行综述。