From the Cover: A Middle Eocene lowland humid subtropical “Shangri-La” ecosystem in central Tibet

Tibet’s ancient topography and its role in climatic and biotic evolution remain speculative due to a paucity of quantitative surface-height measurements through time and space, and sparse fossil records. However, newly discovered fossils from a present elevation of ∼4,850 m in central Tibet improve substantially our knowledge of the ancient Tibetan environment. The 70 plant fossil taxa so far recovered include the first occurrences of several modern Asian lineages and represent a Middle Eocene (∼47 Mya) humid subtropical ecosystem. The fossils not only record the diverse composition of the ancient Tibetan biota, but also allow us to constrain the Middle Eocene land surface height in central Tibet to ∼1,500 ± 900 m, and quantify the prevailing thermal and hydrological regime. This “Shangri-La”–like ecosystem experienced monsoon seasonality with a mean annual temperature of ∼19 °C, and frosts were rare. It contained few Gondwanan taxa, yet was compositionally similar to contemporaneous floras in both North America and Europe. Our discovery quantifies a key part of Tibetan Paleogene topography and climate, and highlights the importance of Tibet in regard to the origin of modern Asian plant species and the evolution of global biodiversity.

The Tibetan Plateau, once thought of as entirely the product of the India–Eurasia collision, is known to have had significant complex relief before the arrival of India early in the Paleogene (1–3). This large region, spanning ∼2.5 million km², is an amalgam of tectonic terranes that impacted Asia long before India’s arrival (4, 5), with each accretion contributing orographic heterogeneity that likely impacted climate in complex ways. During the Paleogene, the Tibetan landscape comprised a high (>4 km) Gangdese mountain range along the southern margin of the Lhasa terrane (2), against which the Himalaya would later rise (6), and a Tanghula upland on the more northerly Qiangtang terrane (7). Separating the Lhasa and Qiangtang blocks is the east–west trending Banggong-Nujiang Suture (BNS), which today hosts several sedimentary basins (e.g., Bangor, Nyima, and Lunpola) where >4 km of Cenozoic sediments have accumulated (8). Although these sediments record the climatic and biotic evolution of central Tibet, their remoteness means fossil collections have been hitherto limited. Recently, we discovered a highly diverse fossil assemblage in the Bangor Basin. These fossils characterize a luxuriant seasonally wet and warm Shangri-La forest that once occupied a deep central Tibetan valley along the BNS, and provide a unique opportunity for understanding the evolutionary history of Asian biodiversity, as well as for quantifying the paleoenvironment of central Tibet.^*Details of the topographic evolution of Tibet are still unclear despite decades of investigation (4, 5). Isotopic compositions of carbonates recovered from sediments in some parts of central Tibet have been interpreted in terms of high (>4 km) Paleogene elevations and aridity (9, 10), but those same successions have yielded isolated mammal (11), fish (12), plant (13–18), and biomarker remains (19) more indicative of a low (≤3-km) humid environment, but how low is poorly quantified. Given the complex assembly of Tibet, it is difficult to explain how a plateau might have formed so early and then remained as a surface of low relief during subsequent compression from India (20). Recent evidence from a climate model-mediated interpretation of palm fossils constrains the BNS elevation to below 2.3 km in the Late Paleogene (16), but more precise paleoelevation estimates are required. Further fossil discoveries, especially from earlier in the BNS sedimentary records, would document better the evolution of the Tibetan biota, as well as informing our understanding of the elevation and climate in an area that now occupies the center of the Tibetan Plateau.Our work shows that the BNS hosted a diverse subtropical ecosystem at ∼47 Ma, and this means the area must have been both low and humid. The diversity of the fossil flora allows us to 1) document floristic links to other parts of the Northern Hemisphere, 2) characterize the prevailing paleoclimate, and 3) quantify the elevation at which the vegetation grew. We propose that the “high and dry” central Tibet inferred from some isotope paleoaltimetry (9, 10) reflects a “phantom” elevated paleosurface (20) because fractionation over the bounding mountains allowed only isotopically light moist air to enter the valley, giving a false indication of a high elevation (21).     

短柄龙胆的形态组织学研究

目的 对短柄龙胆进行形态组织学研究.方法 采用原植物鉴别、性状鉴别、显微鉴别的方法.结果与结论 确定了短柄龙胆在形态组织学方面的鉴别特征,为短柄龙胆的鉴别提供了依据.     

电话回访应用于边远藏区白内障术后患者的满意度调查分析

目的：通过电话回访评估在四川甘孜藏族自治州人民医院进行白内障手术患者对术后视力及舒适满意度的调查分析。

方法：对2012年于我院行白内障手术的患者建立档案,根据术前是否伴有其它眼科疾病和(或)在出院时是否伴有手术并发症进行分类,并对他们在术后3mo进行电话回访,回访评估术后视力恢复情况及是否伴有其它不适。

结果：我院在2012年总共行888例白内障手术,678位患者,其中女性364例(54%),大多数患者(93%)术前双眼视力视力严重下降或盲(<6/60)。在记录的881例手术中,主要的术前伴随眼疾：视网膜疾病30例,慢性虹膜疾病11例; 主要术中并发症：角膜水肿44例,玻璃体溢出19例。电话回访结果显示：3mo后508位患者(75%)被电话回访至少一次,在其中参加回访评估的588例手术中, 485(82%)叙述相比较与出院时“变好”的视力和(或)伴有不舒适, 85(15%)“一样”的视力和(或)伴有不舒适,18(3%)“变差”的视力和(或)伴有不舒适。回访结果显示：术后3mo后,伴有术前眼疾和(或)手术并发症患者中叙述视力差和(或)术后不适的比例相比较不伴有术前眼疾和(或)手术并发症患者显著升高(Chi-square=6.575, P=0.037).

结论：在出院时那些白内障患者特别需要术后3mo回访是可预料的,而电话回访增加了回访的可能性。而且需要提高处理患者手术并发症或治疗术前伴随眼疾的能力必须通过提高当地的眼科服务能力来实现。     

青海地区藏族肺结核患者血清SIL-2R、IFN-γ、HBD-2、MCP-1的表达及意义

目的 通过检测肺结核(tuberculosis,TB)患者血清中可溶性白介素2受体(solubleinterleukin2 receptor,SIL-2R)、γ干扰素(γ Interferon,IFN-γ)、人β-防御素-2(humanβ-defense-2,HBD-2)、单核细胞趋化蛋白-1(monocyte chemotactant protein-1,MPC-1)的表达水平,探讨其在肺结核中的作用.方法 选择藏族肺结核患者为病例组,应用双抗体夹心酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)检测血清中SIL-2R、IFN-γ、HBD-2、MPC-1的含量,并选择同期进行健康体检的藏族同胞为对照组,进行比较分析.结果 病例组血清中SIL-2R为(344.01±92.92) pg/ml、INF-γ为(243.84±51.40) pg/ml、HBD-2为(238.24±44.26) ng/L、MPC-1为(251.01 ±64.71) ng/L,表达水平均高于对照组,差异有统计学意义(均有P＜0.001);肺结核患者中痰菌涂片阳性组可溶性SIL-2R、IFN-γ、HBD-2、MPC-1的表达水平高于阴性组,差异有统计学意义(均有P＜0.05).结论 藏族肺结核患者血清中可溶性SIL-2R、IFN-γ、HBD-2、MPC-1的表达水平明显升高,这些细胞因子可能与肺结核病感染的程度、演变等有关.     

青藏高原藏羚羊粪便携带小双节RNA病毒调查分析的研究

目的 调查小双节RNA病毒(Picobirnavirus,PBV)在藏羚羊粪便中的携带情况,并对序列进行分析。方法 提取160份藏羚羊粪便样品总RNA,利用转录组测序得到藏羚羊PBV序列,并且采用巢式RT-PCR验证大于1 500 nt接近全长的序列。基于藏羚羊PBV的 RNA依赖性RNA聚合酶(RNA-dependent RNA polymerase, RdRp)氨基酸序列构建系统进化树;提取藏羚羊PBV起始密码子上游20个核苷酸,分析核糖体结合位点(ribosomal binding site,RBS)在5'非编码区(5'untranslated region, 5'UTR)的分布情况。结果 转录组测序结合巢式RT-PCR得到7份藏羚羊粪便携带分节段(8条segment 1和13条segment 2)和不分节段PBV(1条不分节段的PBV)。14条藏羚羊PBV RdRp核苷酸和氨基酸序列一致性为25.4%~97.7%和16.4%~98.2%。系统发育分析表明14条藏羚羊PBV序列处于分散分布,其中11条序列分散在基因I群(genogroup I,GI),3条分散在基因II群(genogroup I,GII),它们与亲缘关系最近的物种核苷酸和氨基酸序列一致性分别为52.3%~76.4%和50.9%~79.5%;藏羚羊与旱獭不分节段PBV分布于GII中,核苷酸序列一致性为47.6%,氨基酸序列一致性为45.8%。经比对发现有13条藏羚羊PBV的5'UTR存在RBS。结论 藏羚羊是PBV潜在宿主之一, 藏羚羊PBV序列具有高度遗传多样性。     

海拔3800m以上世居藏族健康成人心率变异性分析

目 的 观 察 海 拔 ３８００ｍ 以 上 世 居 藏 族 健 康 成 人 心 率 变 异 性 各 项 指 标 的 临 床 意 义 。 方法 对 １００ 例 高海 拔 世 居 藏族 成 人（ 观 察 组）与 ７５ 例 西 宁 地 区 藏 族 成 人（ 对 照 组 ）进 行 全 程 ２４ｈ 动态 心 电 图 检 查 ， 并 行 心 率 变 异 性 时 域 和 频 域 分 析 对 比 。 结 果 与 对 照 组 比 较 ， 观 察 组 ｒＳＭ Ｍ Ｄ 和ＰＮ Ｎ５０ 增高（Ｐ＜０．０５，０．０１）。 结论 提 示海 拔 ３８００ｍ 以 上世 居 藏族 健康 成 人的 迷走 神 经张 力较 高 。     

藏汉两族人群内皮功能差异的研究

目的:探讨藏汉两族人群内皮功能(FMD)的差异。方法:在空腹状态下,使用B型超声对272例藏族男性和580例汉族男性进行肱动脉舒张功能检测。对比两组人群各项基本指标和FMD变化。结果:藏族人群肱动脉直径的绝对和相对变化低于汉族人群(P<0.001)。结论:藏汉两族人群内皮功能存在差异。     

藏药石榴莲花散中鞣花酸和胡椒碱含量测定方法研究

目的： 建立藏药石榴莲花散中鞣花酸和胡椒碱含量测定方法,以完善其质量标准。方法： 采用高效液相色谱法测定制剂中石榴子和诃子的鞣花酸含量,采用ODS-2 HYPERSIL C₁₈色谱柱（4.6 mm×250mm,5 μm）,以乙腈-0.2%磷酸（15：85）为流动相,流速1.0 mL·min^-1,检测波长254 nm,柱温30℃;采用高效液相色谱法测定制剂中荜茇的胡椒碱含量,采用ODS-2 HYPERSIL C₁₈色谱柱（4.6mm×250 mm,5μm）,以乙腈-水（40：60）为流动相,流速1.0 mL·min^-1,检测波长343 nm,柱温30℃。结果： 鞣花酸进样量在5.065~25.325 μg范围内呈良好线性关系（r=0.9999）,平均回收率为97.5%,RSD=1.5%（n=6）;胡椒碱进样量在10.414~52.071 μg范围内呈良好线性关系（r=1.0000）,平均回收率为99.6%,RSD=0.6%（n=6）。结论： 该方法可准确测定石榴莲花散中鞣花酸和胡椒碱的含量,有助于提高石榴莲花散的质量标准。     

Lower cardiovagal tone and baroreflex sensitivity associated with hepatic insulin resistance and promote cardiovascular disorders in Tibetan minipigs induced by a high fat and high cholesterol diet

Aims

A long-term high-fat/cholesterol (HFC) diet leads to hepatic insulin resistance (IR), which is associated with autonomic dysfunction and cardiovascular diseases risk increasing. However, whether this occurs in Tibetan minipigs remains unknown. We tested that a long-term HFC diet caused hepatic IR and promote cardiovascular disorders in Tibetan minipigs, and are associated with the reduction of cardiovagal tone and baroreflex sensitivity (BRS).

新疆出土梵文医方集《鲍威尔写本》与中国传统医学的关系

新疆库车出土的梵文桦树皮写本因英属印度陆军中尉鲍威尔在库车购买而名“鲍威尔写本”.该写本后经英国籍德国裔东方学家霍恩勒研究、考释、刊布,共7卷,前3卷为医方集.经考证,其中的“达子香叶散”即现今藏医的“杜鹃大臣散”.经与中医、藏医、蒙医、维医等中国传统医学中的药方相比较,《鲍威尔写本》与藏医、蒙医关系近,与中医、维医关系远,曾影响过中国传统医学.