Different duration of high-altitude pre-exposure associated with the incidence of acute mountain sickness on Jade Mountain

Objective

The objective of this study is to determine the association between the duration of high-altitude (> 3000 m) pre-exposure and acute mountain sickness (AMS) incidence.

Methods

A prospective observational study was conducted on 2 random days each month from April 2007 to March 2008 at Paiyun Lodge (3402 m), Jade Mountain, Taiwan. Demographic data, prior AMS history, symptoms, and scores and the days and times of high-altitude pre-exposure within the preceding 2 months were obtained from lowland (< 1500 m) trekkers.

Results

Totally, 1010 questionnaires were analyzed; 106, 76, and 828 trekkers had pre-exposure lasting at least 3 days (group 1), less than 3 days (group 2), and 0 days (group 3), respectively. Acute mountain sickness incidence was significantly higher in groups 2 and 3 than in group 1 (21.70%, 35.53%, 37.08%, respectively; P = .008). Logistic regression analysis indicated a significantly lower AMS risk in group 1 (group 1, P = .004; odds ratio [OR], 0.479; 95% confidence interval [CI], 0.290-0.791; group 2, P = .226; OR, 0.725; 95% CI, 0.430-1.221). In group 1, 28 and 78 trekkers had single and intermittent multiple pre-exposure, respectively. There was no difference in the incidence or severity of AMS symptoms between single and intermittent multiple pre-exposure (AMS, P = .838; headache, P = .891; dizziness or lightheadedness, P = .414; fatigue and/or weakness, P = .957; gastrointestinal symptoms, P = .257; difficulty sleeping, P = .804; AMS score, P = .796).

Conclusions

High-altitude pre-exposure lasting at least 3 days within the preceding 2 months was associated with a significant lower AMS incidence during a subsequent ascent among Jade Mountain trekkers.     

Enhancement of saporin toxicity against U937 cells by Gypsophila saponins

Saporin, a type I ribosome-inactivating protein (RIP), removes an adenine residue from the 28S ribosomal RNA as part of a process that leads to inhibition of protein synthesis. As a result, saporin has been shown to exert a strong toxicity in the immune system against macrophages. However, studies have shown that macrophage-like U937 cells are fully resistant against low concentrations of unmodified and his-tagged saporin solutions (6 pM) that normally kill macrophages and APC. In the studies reported here, we noted that with these cells, these RIP solutions only became highly cytotoxic when they were used in a combined treatment with Gypsophila saponins. We determined that this cytotoxicity was the result of an induction of apoptosis triggered by the now-internalized saporin molecules that had previously remained outside of these cells. The results here indicate that the Gypsophila saponins induce, in some manner yet to be fully defined, a stimulation of the endocytosis of saporin by these cells.     

Porous beta-tricalcium phosphate/collagen composites prepared in an alkaline condition

Bone substitute materials with natural bone-like structure are considered to be favorable for bone regeneration. In this work, porous beta-tricalcium phosphate (beta-TCP)/collagen composite consisting of bone-like microstructural units was prepared using nanosized beta-TCP particles and alkaline-disassembled collagen. The resulting composite showed a good interconnecting porous structure with approximately 90% porosity and 100 approximately 300 microm pore size. The pore walls were dense, and the combination status of collagen and nanosized beta-TCP particles demonstrated that nanosized beta-TCP particles tightly connected collagen microfibrils as a bone-like microstructural unit. MTT and alkaline phosphatase (ALP) assays showed that the porous composite had enhanced effects on cellular proliferation and activity of osteoblast compared with a control of pure collagen. It is suggested that the adoption of nanosized beta-TCP particles is a main contribution to the formation of the composite with a bone-like microstructural unit, and the unique microstructure could be a main role for the composite to have the positive influence on osteoblast cell proliferation.     

Tailoring of multilayered core-shell nanostructure for multicomponent administration and controllable release of biologically active ions

The biomaterials that can control the active ions delivery to enhance cell activity are regarded as promising bone regenerative materials. In this study, a new approach aiming to layer-by-layer (LbL) assemble the bioavailable zinc ions in the core-shell-like silica@octacalcium phosphate (OCP) nanosphere and to analyze its efficacy on improving controlled-release was reported. Firstly, a pH-responsive electrostatic interaction was used to adsorb zinc ions on silica nanospheres with different zinc concentration, which was followed by coating silica gel layer. Then the nanospheres were LbL assembled with zinc ions and silica gel alternately until the desired multilayered nanospheres were achieved. Finally, the porous OCP shells were capped onto the outside surface of the nanospheres tailored by poly(aspartic acid) sodium molecules. The ion release tests in Tris buffers in vitro indicated that zinc release was controlled by pH and storage capacity, and silicon release was regulated by the OCP shell barrier. A temporal gradient within short times and sustained-dosage for a prolonged time toward the zinc and silicon ions could be obtained in this multilayer system. The results of this organized active ion assembly might open a promising future direction for effective delivery of trace elements in bone defect therapy.     

胫骨高位截骨术治疗膝关节骨性关节炎报告

我科于 1 997年～ 2 0 0 3年应用膝关节外固定加压融合器行高位胫骨截骨术 (HTO)治疗伴有膝内翻畸形的骨性关节炎 1 0例 1 0膝 ,并随访 6个月～ 5年 ,平均 3年 9个月。术后结果 ,股胫角 (FTA)由术前平均 1 84 .7°矫正到平均 1 70 .3° ,评分由术前平均 4 7分 ,增加到平均 85分。手术采用胫骨楔形截骨、双斯氏针加压外固定、胫骨远端前移 1cm ,以改善髌股关节的负重关系。结论 :手术简单 ,止痛效果好 ,功能恢复快     

骨髓间充质干细胞复合脱钙骨基质修复兔膝关节全层软骨缺损的实验

目的:研究骨髓间充质干细胞(mesenchymal stem cells, MSCs)复合脱钙骨基质(deminerized bone matrix, DBM)修复兔膝关节全层软骨缺损的疗效. 方法:MSCs取自4～6 mo龄2.5～3.5 kg的青紫兰兔,体外分离培养后种植于DBM支架上体外培养,再移植于兔膝关节全层软骨缺损模型处. 实验动物选用健康的青紫兰兔36只,随机分成A, B, C 3个处理组各12只,A处理组(MSCs/DBM)双侧股骨髁间窝软骨缺损处植入DBM吸附体外分离培养的自体MSCs复合物;B处理组(DBM)单纯植入DBM;C处理组(对照)不作任何植入. 分别于术后4, 8和12 wk各处死4只兔子,取材进行大体、组织学及免疫组化染色观察,根据关节软骨组织学计分标准进行评分,数据输入SPSS 10.0软件统计分析,比较各组的评分差异是否具有统计学意义. 结果:MSCs复合DBM所修复组织为透明软骨样修复;而单纯DBM移植组和对照组为纤维性修复. 对术后12 wk大体及组织学形态进行评分. 按完全随机设计进行方差分析和SNK-q检验,结果显示,SMCs/DBM组明显优于DBM植入组和对照组(P<0.05);DBM组优于对照组(P<0.05). 结论:运用软骨组织工程的原理,以DBM为支架材料的自体MSCs移植是一种修复软骨缺损的行之有效的方法.     

围术期体温监测的最佳证据总结

目的 检索围术期体温监测相关证据,并对其最佳证据进行总结.方法 系统检索国内外数据库、指南网及专业协会网站等关于围术期体温监测的指南、临床决策、专家共识、系统评价等.结果 纳入18篇文献,其中指南6篇、专家共识3篇、证据总结2篇、临床决策3篇以及系统评价4篇,共提炼出包括护理评估、监测部位与工具、监测频率与监测注意事宜...     

Differential fadE28 expression associated with phenotypic virulence of Mycobacterium tuberculosis

Ability to persist in human macrophages is central to the virulence of Mycobacterium tuberculosis and is not invariable among various strains. Differential gene expression that is associated with phenotypic virulence may provide additional information of virulent genes involved in the pathogenesis of M. tuberculosis, which is not fully elucidated. Three hypervirulent strains of M. tuberculosis isolated from patients suffering with tuberculous meningitis were shown to grow more rapidly inside human macrophages in a previous study. In the current investigation, expression of 7 mycobacterial genes (fadE28, mce1A, mymA, acr, sigA, sugC, and Rv3723) of these strains during ex vivo macrophage challenge and in vitro acid shock was quantified by real-time PCR. Using rrs gene as a normalisation gene, fadE28 gene exhibited differential gene expression that is associated with phenotypic virulence, whereas the other 6 genes showed indistinguishable expression patterns. Up-regulation of fadE28 gene in the hypervirulent strains may account for virulence by increasing the efficiency of beta-oxidation, which is important for the persistence in macrophages as M. tuberculosis uses fatty acids preferably inside phagosome of macrophages. The fadE28 gene, together with its adjacent genes may also be critical in the process of lipid modification that could facilitate parasitism in human macrophages.     

Model-independent, multimodality deformable image registration by local matching of anatomical features and minimization of elastic energy

With respect to the demands of adaptive and 4D-radiotherapy applications, an algorithm is proposed for a fully automatic, multimodality deformable registration that follows the concept of translational relocation of regularly distributed image subvolumes governed by local anatomical features. Thereby, the problem of global deformable registration is broken down to multiple independent local registration steps which allows for straightforward parallelization of the algorithm. In a subsequent step, possible local misregistrations are corrected for by minimization of the elastic energy of the displacement field under consideration of image information. The final displacement field results from interpolation of the subvolume shift vectors. The algorithm can employ as a similarity measure both the correlation coefficient and mutual information. The latter allows the application to intermodality deformable registration problems. The typical calculation time on a modern multiprocessor PC is well below 1 min, which facilitates almost-interactive, "online" usage. CT-to-MRI and CT-to-cone-beam-CT registrations of head-and-neck data sets are presented, as well as inhale-to-exhale registrations of lung CT data sets. For quantitative evaluation of registration accuracy, a virtual thorax phantom was developed; additionally, a landmark-based evaluation on four lung respiratory-correlated CT data sets was performed. This consistently resulted in average registration residuals on the order of the voxel size or less (3D-residuals approximately 1-2 mm). Summarizing, the presented algorithm allows an accurate multimodality deformable registration with calculation times well below 1 min, and thus bears promise as a versatile basic tool in adaptive and 4D-radiotherapy applications.