The Surgical Site Infection Risk Score (SSIRS): A Model to Predict the Risk of Surgical Site Infections

Background

Surgical site infections (SSI) are an important cause of peri-surgical morbidity with risks that vary extensively between patients and surgeries. Quantifying SSI risk would help identify candidates most likely to benefit from interventions to decrease the risk of SSI.

Methods

We randomly divided all surgeries recorded in the National Surgical Quality Improvement Program from 2010 into a derivation and validation population. We used multivariate logistic regression to determine the independent association of patient and surgical covariates with the risk of any SSI (including superficial, deep, and organ space SSI) within 30 days of surgery. To capture factors particular to specific surgeries, we developed a surgical risk score specific to all surgeries having a common first 3 numbers of their CPT code.

Results

Derivation (n = 181 894) and validation (n = 181 146) patients were similar for all demographics, past medical history, and surgical factors. Overall SSI risk was 3.9%. The SSI Risk Score (SSIRS) found that risk increased with patient factors (smoking, increased body mass index), certain comorbidities (peripheral vascular disease, metastatic cancer, chronic steroid use, recent sepsis), and operative characteristics (surgical urgency; increased ASA class; longer operation duration; infected wounds; general anaesthesia; performance of more than one procedure; and CPT score). In the validation population, the SSIRS had good discrimination (c-statistic 0.800, 95% CI 0.795–0.805) and calibration.

Conclusion

SSIRS can be calculated using patient and surgery information to estimate individual risk of SSI for a broad range of surgery types.     

关于神经病学PBL教学中心理因素的思考

神经病学是涉及多个基础学科的临床专门学科,其内容复杂抽象,令学生望而生畏。PBL是学生自主学习建构知识和教师引导的教学模式,有利于学生克服畏难情绪,提高学习效率。根据我们的实践体会,教师与学生的心理是影响PBL教学效果的重要因素。只有把握好教学过程中的心理因素,才能使PBL的优势真正得以体现。     

Wistar大鼠幼年期丰富环境刺激对其社会竞争行为的影响

目的：探讨大鼠幼年期丰富环境经历对其成年后焦虑样行为和社会竞争行为的影响。方法：幼年期Wistar大鼠（生后21天）分为标准饲养组（对照组）和丰富环境刺激（EE）组。对照组为持续在标准实验室饲养条件下饲养;丰富环境组为生后21天至行为学检查时持续在丰富环境下饲养。在生后70天进行行为学检测：采用高架十字迷宫方法测试焦虑样行为;采用社会优势管道试验观察社会竞争性行为。结果：高架十字迷宫实验结果显示,与对照组相比,丰富环境组在开放臂的时间和次数显著增加;优势管道实验结果显示丰富环境刺激组大鼠的社会竞争力明显下降。结论：大鼠幼年期丰富环境刺激可改善大鼠的焦虑样情绪,但导致大鼠社会竞争力下降。     

液质连用分析重组胰高血糖素样肽-1受体激动剂肽图

目的：建立高效液相系统肽图分析法,用于重组胰高血糖素样肽-1受体激动剂（rExendin-4）的质量控制。方法：应用高效液相系统摸索最佳胰蛋白酶切和色谱条件,并采用液质联用系统分析肽段的精确相对分子量和氨基酸序列。结果：根据酶切条件摸索,确定酶切条件为：rExendin-4原液与胰蛋白酶按照质量比为100：1混匀,37℃酶切4小时,根据肽段的色谱保留时间、相对分子质量及对其碰撞诱导解离质谱的解析结果,归属出肽图中各肽段所在的色谱峰,与理论值完全一致。结论：本法精确度高、重复性好、自动化程度高,能够用于rExendin-4原液肽图分析。     

不同粘度对比剂对冠状动脉造影患者肾功能的影响

目的：对比剂肾病（CIN）是介入治疗中常见并发症之一。由于对比剂肾病发病机制复杂,其确切的机制尚不明确,有研究认为应用渗透压相似的对比剂,高粘度组对比剂引起CIN的几率明显高于低粘度组。本研究探讨接受不同粘度对比剂冠状动脉造影检查的患者术后引起肾功能损害的差异及其可能的机制。方法：80例接受冠状动脉造影检查的患者随机分为两组。分别为20℃碘海醇组、37℃碘海醇组,每组各40例。分别于冠脉造影前8h、冠脉造影后48h采集同一患者肘正中静脉血进行血清肌酐（Scr）、血清胱抑素C（CysC）检测,并对数据进行统计学分析。结果：两组患者组间比较基本资料无明显差异,两组患者术后Ser、CysC较术前均升高,差异均有统计学意义（P〈0．05）;20℃碘海醇组术后Scr较37℃碘海醇组升高不明显,差异无统计学意义（P〉0．05）;20℃碘海醇组术后CysC较37℃碘海醇组升高明显,差异有统计学意义（P〈0．05）。结论：冠脉造影检查时．对比剂对患者的肾功能有损害;选择低粘度对比剂可能减少其对冠状动脉造影患者的肾功能的不良影响;其作用机制可能与对比剂改变血液粘滞性,从而影响肾血流有关。     

Toll‐like receptor 9 protects non‐immune cells from stress by modulating mitochondrial ATP synthesis through the inhibition of SERCA2

Toll‐like receptor 9 (TLR9) has a key role in the recognition of pathogen DNA in the context of infection and cellular DNA that is released from damaged cells. Pro‐inflammatory TLR9 signalling pathways in immune cells have been well investigated, but we have recently discovered an alternative pathway in which TLR9 temporarily reduces energy substrates to induce cellular protection from stress in cardiomyocytes and neurons. However, the mechanism by which TLR9 stimulation reduces energy substrates remained unknown. Here, we identify the calcium‐transporting ATPase, SERCA2 (also known as Atp2a2), as a key molecule for the alternative TLR9 signalling pathway. TLR9 stimulation reduces SERCA2 activity, modulating Ca²⁺ handling between the SR/ER and mitochondria, which leads to a decrease in mitochondrial ATP levels and the activation of cellular protective machinery. These findings reveal how distinct innate responses can be elicited in immune and non‐immune cells—including cardiomyocytes—using the same ligand‐receptor system.     

Characterizing the relative orientation and dynamics of RNA A-form helices using NMR residual dipolar couplings

We present a protocol for determining the relative orientation and dynamics of A-form helices in 13C/15N isotopically enriched RNA samples using NMR residual dipolar couplings (RDCs). Non-terminal Watson-Crick base pairs in helical stems are experimentally identified using NOE and trans-hydrogen bond connectivity and modeled using the idealized A-form helix geometry. RDCs measured in the partially aligned RNA are used to compute order tensors describing average alignment of each helix relative to the applied magnetic field. The order tensors are translated into Euler angles defining the average relative orientation of helices and order parameters describing the amplitude and asymmetry of interhelix motions. The protocol does not require complete resonance assignments and therefore can be implemented rapidly to RNAs much larger than those for which complete high-resolution NMR structure determination is feasible. The protocol is particularly valuable for exploring adaptive changes in RNA conformation that occur in response to biologically relevant signals. Following resonance assignments, the procedure is expected to take no more than 2 weeks of acquisition and data analysis time.     

The use of critical levels for determining plant response to ozone in Europe and in North America

Critical levels to determine plant response to ozone (O3) have been used in Europe since the 1980s, utilizing the concentration-based AOT40 to relate plant response to ambient O3 exposure. More recently, there has been progress in Europe toward utilizing flux-based critical levels, because plant response is more closely related to O3 uptake than to the amount of O3 in ambient air. Flux-based critical levels are plant species specific; data for parameterization of flux-based critical levels models are lacking for most plant species. Although flux-based critical levels are now being used for a limited number of agricultural crops and tree species where data are available, the use of flux-based critical levels is limited by the lack of adequate consideration and incorporation of plant internal detoxification mechanisms in flux modeling. Critical levels have not been used in North America; however, recent interest in the U.S. and Canada for using critical loads for nitrogen and sulfur has generated interest in using critical levels for O3. A major obstacle for utilization of critical levels in North America is that ambient air quality standards for O3 in the U.S. and Canada are concentration based. It appears that cumulative exposure-based metrics, particularly when implemented with a quantification of peak concentrations and environmental variables, such as a drought index, are currently the most useful to relate O3 to vegetation response. Because data are unavailable to quantify detoxification potential of vegetation, effective flux models are not available to determine plant response to O3.     

C-type lectin-like molecule-1 (CLL1)-targeted TRAIL augments the tumoricidal activity of granulocytes and potentiates therapeutic antibody-dependent cell-mediated cytotoxicity

The therapeutic effect of anti-cancer monoclonal antibodies stems from their capacity to opsonize targeted cancer cells with subsequent phagocytic removal, induction of antibody-dependent cell-mediated cytotoxicity (ADCC) or induction of complement-mediated cytotoxicity (CDC). The major immune effector cells involved in these processes are natural killer (NK) cells and granulocytes. The latter and most prevalent blood cell population contributes to phagocytosis, but is not effective in inducing ADCC. Here, we report that targeted delivery of the tumoricidal protein tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to granulocyte marker C-type lectin-like molecule-1 (CLL1), using fusion protein CLL1:TRAIL, equips granulocytes with high levels of TRAIL. Upon CLL1-selective binding of this fusion protein, granulocytes acquire additional TRAIL-mediated cytotoxic activity that, importantly, potentiates antibody-mediated cytotoxicity of clinically used therapeutic antibodies (e.g., rituximab, cetuximab). Thus, CLL1:TRAIL could be used as an adjuvant to optimize the clinical potential of anticancer antibody therapy by augmenting tumoricidal activity of granulocytes.