Biomechanical comparison of stemless humeral components in total shoulder arthroplasty

BackgroundThe purpose of this study was to compare initial fixation strength between various stemless and stemmed humeral components and to correlate implant fixation strength with bone mineral density (BMD).MethodsFive humeral stem designs were investigated: Stemless-A (four hollow fins), Stemless-B (central body, three solid fins), Stemless-C (central screw, peripheral rim-fit), Short stem (50 mm), and Standard stem (130 mm). Fifty cadaveric human humerii were obtained and divided into five groups. BMD within the humeral head was determined for all samples. The mean BMD was similar between groups. The 25 samples with the lowest and highest BMDs were categorized as “Low” and “High,” respectively, with a BMD threshold of 0.35 g/cm², creating BMD subgroups. After implantation, each sample underwent a standardized biomechanical testing protocol, with axial loading followed by torsional loading. Sensors attached to the specimen recorded micromotion throughout testing. Axial loading consisted of cyclic loading for 100 cycles at 3 peak forces (220, 520, and 820 N). Torsional loading consisted of 100 cycles of internal/external rotation at 0.1 Hz at 6 peak torques, or until failure (±2.5, 5, 7.5, 10, 12.5, and 15 Nm). Failure was defined as the torque at which any bone fracture, implant detachment from anchor/stem, or an excess of 50° internal/external rotation occurred. Groups and BMD subgroups were compared.ResultsAt maximal axial loading, Stemless-B demonstrated greater micromotion (540 μm) than Stemless-C (192 μm) (P = .003). Stemless-B and Stemless-A (387 μm) also had greater micromotion than Short stem (118 μm, P < .001, P = .03) and Standard stem (85 μm, P < .001, P = .01). When comparing low-BMD samples at maximal axial loading, these differences were accentuated, but comparison of high-BMD samples showed no significant differences between groups. Torsional testing demonstrated that Standard stem failed at greater torque (7.2 Nm) than Stemless-B (2.3 Nm, P < .001), Stemless-A (1.9 Nm, P < .001), and Stemless-C (3.9 Nm, P = .01). When comparing torsional testing results of low-BMD samples, both Standard stem and Short stem failed at greater torque than Stemless-B (P = .02, P = .003) and Stemless-A (P = .03, P = .004) but failed at a similar torque to Stemless-C. Torsional testing of high-BMD samples showed that Standard stem failed at a greater torque than all stemless designs.ConclusionStemless humeral implants should be used with caution in low-BMD settings (<0.35 g/cm²). A central screw and peripheral rim-fit stemless anchor design demonstrated greater fixation strength at low BMD when compared with other designs, while all stemless designs performed similarly at high BMD.Level of evidenceBasic Science Study; Cadaveric Study     

Therapeutic augmentation of NO-sGC-cGMP signalling: lessons learned from pulmonary arterial hypertension and heart failure

Heart Failure Reviews - The nitric oxide (NO)–guanylate cyclase (GC)–cyclic guanosine monophosphate (cGMP) pathway plays an important role in cardiovascular, pulmonary and renal...     

外周血单个核细胞内人类免疫缺陷病毒DNA和RNA定量对病毒转录活性的区分

目的基于人类免疫缺陷病毒Ⅰ型(HIV-1)感染者外周血单个核细胞(PBMCs)中HIV-1总DNA和RNA定量检测结果对感染细胞内病毒的转录活性进行区分。方法采集2017年10月至2018年12月于哈尔滨医科大学附属第四医院感染科就诊的HIV-1感染者血液样本,分离PBMCs细胞,采用PCR荧光探针法对PBMCs细胞内HIV-1总DNA和RNA进行定量检测,并计算两者比值(Ratio)。根据Ratio值筛选出HIV-1转录活跃组样本和相对非活跃组样本,另外选择健康人PBMCs样本作为对照组。对3组样本进行基因转录组表达谱检测以及人口特征差异性检验,并对基因表达谱检测结果进行主成分分析以验证对3组样本病毒转录活性区分的准确性。结果从60例感染HIV-1患者的PBMCs样本中筛选出HIV-1转录活跃组样本(10例)和相对非活跃组样本(11例),另外选择6例健康人PBMCs样本作为对照组。其中转录活跃组样本Ratio值为165.2~738.93,平均为(339.27±189.68);相对非活跃组Ratio值为4.67~42.39,平均为(17.65±11.78)。转录活跃组和相对非活跃组样本间的CD4+T细胞计数(P=0.049)和Ratio值(P<0.001)差异均具有统计学意义;3组样本年龄(P=0.989)和性别(P=0.650)分布差异无统计学意义。对3组样本的PBMCs基因表达谱主成分分析结果显示:对照组与HIV-1感染者(包括转录活跃组和相对非活跃组)间区分明显。转录活跃组和相对非活跃组间有部分样本重合,同时结果也显示当HIV-1感染者的CD4+T淋巴细胞计数与健康人无显著差异时,其细胞内的基因表达与健康人接近。结论基于HIV-1总DNA和RNA定量检测结果及两者间比值可以较好地区分PBMCs内病毒转录活性。HIV-1感染细胞内部病毒的不同转录激活状况可导致其基因表达谱的异质性。     

基于正交试验的肾造瘘管固定方案研究

目的 探讨基于正交试验的肾造瘘管不同固定方案的比较效果。方法 将14Fr硅胶肾造瘘管固定在聚乙烯展板和拉力显示器上，以固定材料、固定方法、面积为3个影响因素，每个因素3个水平，每组进行3次试验再求平均值作为最后拉力值F，共进行9个固定方案共27次试验。利用L9（33）正交试验矩阵研究不同材料（医用橡皮膏、医用透气胶带、医用无纺布胶带）、固定方法（交叉固定法、“工”字固定法和改良“工”字固定法）及面积(16 cm2、24 cm2、32 cm2）对肾造瘘管固定强度的影响。结果 正交试验所选的3种影响因素中，对拉力值影响显著性排序为：材料＞方法＞面积；3种固定材料中，医用橡皮膏固定强度最大。结论 肾造瘘管固定方案中，最佳固定组合为以医用橡皮膏结合改良“工”字法固定，可为临床管道固定方案的选择提供参考。     

Effect of iron deficiency without anaemia on days alive and out of hospital in patients undergoing valvular heart surgery

Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml^-1 or < 300 ng.ml^-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l^-1, 143 (133–150 [120–179]) g.l^-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.     

China special issue on gastrointestinal tumors-Radiological features of pathological complete response in mismatch repair deficient colorectal cancer after neoadjuvant PD-1 blockade: A post hoc analysis of the PICC phase II trial

Neoadjuvant programmed cell death protein 1 (PD-1) blockade exhibits promising efficacy in patients with mismatch repair deficient (dMMR) colorectal cancer (CRC). However, discrepancies between radiological and histological findings have been reported in the PICC phase II trial (NCT 03926338). Therefore, we strived to discern radiological features associated with pathological complete response (pCR) based on computed tomography (CT) images. Data were obtained from the PICC trial that included 36 tumors from 34 locally advanced dMMR CRC patients, who received neoadjuvant PD-1 blockade for 3 months. Among the 36 tumors, 28 (77.8%) tumors achieved pCR. There were no statistically significant differences in tumor longitudinal diameter, the percentage change in tumor longitudinal diameter from baseline, primary tumor sidedness, clinical stage, extramural venous invasion status, intratumoral calcification, peritumoral fat infiltration, intestinal fistula and tumor necrosis between the pCR and non-pCR tumors. Otherwise, tumors with pCR had smaller posttreatment tumor maximum thickness (median: 10 mm vs 13 mm, P = .004) and higher percentage decrease in tumor maximum thickness from baseline (52.9% vs 21.6%, P = .005) compared to non-pCR tumors. Additionally, a higher proportion of the absence of vascular sign (P = .003, odds ratio [OR] = 25.870 [95% CI, 1.357-493.110]), nodular sign (P < .001, OR = 189.000 [95% CI, 10.464-3413.803]) and extramural enhancement sign (P = .003, OR = 21.667 [2.848-164.830]) was observed in tumors with pCR. In conclusion, these CT-defined radiological features may have the potential to serve as valuable tools for clinicians in identifying patients who have achieved pCR after neoadjuvant PD-1 blockade, particularly in individuals who are willing to adopt a watch-and-wait strategy.     

从环境隐喻的角度看外感病的因机证治＊

外感病是感受六淫、疫毒等外界因素引起的疾病，现代医学认为其主要致病因素为细菌或病毒。在以肉身体验为主要认知手段的古代，中医学家不可能发现细菌或病毒的存在，因而中医学家往往以天人相应的整体观来把握认知外感病。由于外感病的发病与传播受到外界气候环境和社会环境的影响，尤与人体的内环境密切相关。有鉴于此，本文从“环境隐喻”的立场出发，对外感病发病的因机证治进行分析。外界的气候环境和社会环境容易被人们感受，而对于古代无法观察人体的内环境，作者借助《论语·季氏将伐颛臾》中“祸起萧墙”的故事，对人体内环境为何与外感病的发病关系密切作以阐释，并通过人参败毒散、达原饮等方证的案例式说明，揭示清理人体内外环境而达治疗外感病的机理。