In Vivo Kinematics of Functional Ankle Instability Patients and Lateral Ankle Sprain Copers During Stair Descent

Patients with mechanic ankle instability experience increased tibiotalar and subtalar joint laxity. However, in vivo joint kinematics in functional ankle instability (FAI) patients and lateral ankle sprain (LAS) copers, especially during dynamic activities, are poorly understood. Ten FAI patients, 10 LAS copers, and 10 healthy controls were included in this study. A dual fluoroscopic imaging system was used to analyze the tibiotalar and subtalar joint kinematics during stair descent. Five key poses of stair descent were analyzed. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint positions in each degree of freedom were compared among the three groups. The tibiotalar joints of FAI patients and LAS copers were significantly more inverted than those of healthy controls during the foot strike (p = 0.016, = 0.264). The subtalar joints of FAI patients were significantly more anteriorly translated (pose 2, p = 0.003, = 0.352; pose 3, p < 0.001, = 0.454; pose 4, p = 0.004, = 0.334), inverted (pose 4, p = 0.027, = 0.234; pose 5,p = 0.034, = 0.221), and externally rotated (pose 4, p = 0.037, = 0.217; pose 5; p = 0.004, = 0.331) than those of healthy controls during the mid‐stance and the heel off. The FAI patients showed excessive tibiotalar inversion and subtalar joint hypermobility during stair descent. Meanwhile, the LAS copers maintained subtalar joint stability, and only showed excessive tibiotalar inversion in foot strike. These data provide insight into the mechanisms behind the development of FAI after initial LAS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1860–1867, 2019     

Hypertension is a risk factor for adverse outcomes in patients with coronavirus disease 2019: a cohort study

Abstract

Background

Comorbidities are commonly seen in patients with coronavirus disease 2019 (COVID-19), but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19.     

Implant wear induces inflammation, but not osteoclastic bone resorption, in RANK(-/-) mice.

Signaling of RANK (receptor activator of nuclear factor kappa B) through its ligand RANKL appears critical in osteolysis associated with aseptic loosening (AL). The purpose of this study was to investigate the role of RANK in a murine osteolysis model developed in RANK knockout (RANK(-/-)) mice. Ultra high molecular weight polyethylene (UHMWPE) debris was introduced into established air pouches on RANK(-/-) mice, followed by implantation of calvaria bone from syngeneic littermates. Wild type C57BL/6 (RANK(+/+)) mice injected with either UHMWPE or saline alone were included in this study. Pouch tissues were collected 14 days after UHMWPE inoculation for molecular and histology analysis. Results showed that UHMWPE stimulation induced strong pouch tissue inflammation in RANK(-/-) mice, as manifested by inflammatory cellular infiltration, pouch tissue proliferation, and increased gene expression of IL-1beta, TNFalpha, and RANKL. However, the UHMWPE-induced inflammation in RANK(-/-) mice was not associated with the osteoclastic bone resorption observed in RANK(+/+) mice. In RANK(+/+) mice subjected to UHMWPE stimulation, a large number of TRAP(+) cells were found on the implanted bone surface, where active osteoclastic bone resorption was observed. No TRAP(+) cells were found in UHMWPE-containing pouch tissues of RANK(-/-) mice. Consistent with the lack of osteoclastic activity shown by TRAP staining, no significant UHMWPE particle-induced bone resorption was found in RANK(-/-) mice. A well preserved bone collagen content (Van Gieson staining) and normal plateau surface contour [microcomputed tomography (microCT)] of implanted bone was observed in RANK(-/-) mice subjected to UHMWPE stimulation. In conclusion, this study provides the evidence that UHMWPE particles induce strong inflammatory responses, but not associated with osteoclastic bone resorption in RANK(-/-) mice. This indicates that RANK signaling is essential for UHMWPE particle-induced osteoclastic bone resorption, but does not participate in UHMWPE particle-induced inflammatory response.     

The effect of MS-818, a pyrimidine compound,on the regeneration of peripheral nerve fibers of mice after a crush injury

One of the pyrimidine compounds, 2-piperadino-6-methyl-5-oxo-5,6-dihydro(7H)pyrrolo[3,4-d]pyrimidine (MS-818), has neurotropic effects in vitro. Therefore, we studied the effect of MS-818 on the regeneration of the peroneal nerve in C57BL/6J mice after a crush injury. Two test groups, which received a daily intraperitoneal injection of 5 mg/kg or 10 mg/kg MS-818, respectively, were compared with controls, which received daily intraperitoneal injections of physiological saline, over a 14-day period. The maximum foot-width ratio (crushed side/uncrushed side) was obtained on days 1, 8 and 14 after the crush injury, and the various morphometric parameters were evaluated at both 5 and 10 mm distal to the proximal portion of the crush site. The significant effects of MS-818 included a larger maximum foot width (P<0.04) and a greater number of unmyelinated axons per nerve at both levels (P<0.003) in both test groups than in controls. MS-818 had no significant effects on body weight, the increase of total transverse fascicular area after the crush injury, the total number of myelinated fibers with their size distributions, or the number of nuclei of Schwann cells and macrophages. Therefore, we conclude that MS-818 promotes axonal sprouting and elongation after a crush injury in mice.     

Kindergarten children's representation and understanding of written number symbols

Two samples of kindergarten children's representation and understanding of written number symbols were examined in two time points in one academic year. About 85% of Chinese five year olds (mean = 5 years 10 months) were able to use conventional number symbols to represent the quantity of 30 or larger. At the end of the kindergarten year, 94% of Chinese six year olds (mean = 6 years 4 months) were able to use conventional number symbols to represent the quantity of 100 or larger. Some Chinese six year olds had problems in representing written addition and subtraction tasks. Children's ability to represent written number symbols, ability to represent written addition and subtraction formula and their performance on written addition and subtraction were closely related. The performance of children in a university-affiliated childcare center was better than that of the center serving working-class families in Time 1, but the performance reversed at the end of the kindergarten year.     

现代医学200词——138．黏附分子

所谓黏附分子是指存在于细胞表面，参与细胞间或细胞与细胞外基质的粘附的分子群的总称。广义来说，纤维连结蛋白、层粘连蛋白、透明质酸等细胞外基质的构成成分也是由细胞分泌并存在于细胞表面，也可归入黏附分子的范畴。但狭义所指的黏附分子是指贯通细胞膜的糖蛋白或构成细胞膜的糖脂质。膜贯通型糖蛋白黏附分子按其构造特征可分为若干家族。在免疫系统中的黏附分子主要分为整合素家族、免疫球蛋白超家族、选择素家族、钙粘素家族、连接蛋白家族以及唾液粘蛋白家族等。     

云南白药对血小板活化的研究

为探讨云南白药对血小板活化的影响 ,应用单克隆抗体法 ,并用流式细胞仪对 2 0 6例男性腹股沟斜疝患者血小板活化分子标志物进行检测 ,同时检测血浆凝血物质和 D-二聚体含量。结果显示 :服药组血小板明显活化与对照组比较有显著性差异 ( P<0 .0 5 ) ,凝血物质和 D-二聚体与对照组比较无差异 ( P>0 .0 5 )。结论 :云南白药能增加血小板活化 ,促进局部止血 ,但它不影响凝血物质和 D-二聚体的含量 ,不增加血栓形成的危险。     

刺鼠信号蛋白对自体移植皮片中酪氨酸酶的活性影响

目的 检测刺鼠信号蛋白对自体移植皮片中酪氨酸酶的活性影响,进一步认识自体移植皮片过度色素沉着的原因。方法 建立过度色素沉着的自体移植皮片的动物模型；利用免疫组织化学方法分别检测刺鼠信号蛋白作用前后自体移植皮片中酪氨酸酶的表达,并与对照治疗组及正常皮肤相比较。结果 酪氨酸酶的表达定位于表皮基底部黑色素细胞的胞浆,在大部分组织中呈阳性表达,经刺鼠信号蛋白作用后酪氨酸酶在自体移植皮片中的表达明显减少,与在其他各对照组中的表达差异有极显著意义（P＜0.01）。结论 刺鼠信号蛋白在自体移植皮片中能竞争性拮抗α-MSH的黑色素合成,使皮片着色能力降低,从而证明皮片移植后表皮细胞中α-MSH的表达上调是皮片呈过度色素沉着的重要原因。     

医学生"网络成瘾症"产生的原因和对策

文章针对目前医学生“网络成瘾症”的现状进行了分析,并指出了产生的原因和解决问题的办法,以求达到标本兼治。最后提出三点预防医学生“网络成瘾症”的对策：一是高校及其附属医院要为医学生营造宽松愉快的学习、生活环境;二是呼吁家长关注医学生身心发展的特殊规律,建立良好的家庭环境;三是建立和完善与网络社会相应的法律法规,规范医学生的网上行为。