Exploration of disease mechanism in acute kidney injury using a multiplex bead array assay: a nested case–control pilot study

Background: Acute kidney injury (AKI) following cardiac surgery with cardiopulmonary bypass (CPB) causes increased morbidity and mortality.

Objective: To evaluate the plasma profile of biomarkers potentially involved in AKI development following CPB.

Methods: In a nested case–control study, plasma levels of 27 biomarkers in 11 AKI cases were compared with 25 controls.

Results: Pre-CPB, plasma levels of epidermal growth factor and macrophage inflammatory protein-1β, 2?h following CPB, soluble vascular cell adhesion molecule-1 (sVCAM-1), fractalkine and macrophage inflammatory protein-1α, and at later time points, sVCAM-1 and interleukin-6 were associated with AKI.

Conclusion: Biomarkers associated with AKI following CPB may merit further study.     

Assessment of risk factors for postoperative cognitive dysfunction after coronary artery bypass surgery: a single-center retrospective cohort study

Aim: To find out risk factors for postoperative cognitive dysfunction (POCD) after coronary artery bypass grafting (CABG), and to provide basis for clinical prevention of POCD. A total of 88 patients who underwent CABG were surveyed with Telephone Questionnaire (TICS-M) for their cognitive impairment after 3, 7, 21, 90, 180 days post-surgery. The occurrence of POCD was diagnosed by Neuropsychological Battery which included Vocabular Learning Test (VLT), Wisconsin Card Sorting Test (WCST), Trail Making Test (TMT) and Symbol Digit Modalities Test (SDMT). The preoperative, intraoperative and postoperative risk factors were assessed by the χ² or t test. Multivariate analysis was used to study the correlation between the risk factors and the occurrence of POCD. Age, aortic plaque, carotid artery stenosis, cerebrovascular disease, anesthesia time, the rate of decline in intraoperative hemoglobin concentration (ΔHb) and systemic inflammatory response syndrome (SIRS) score on postoperative day 2 had statistically significant (P<0.05) influence on the occurrence of POCD. Aortic plaque, carotid artery stenosis, anesthesia time and SIRS score (odds ratio (OR) value > 1, P<0.05) are the risk factors for POCD. The incidence of day-21 and -180 POCD was approximately 26.1 and 22.7%, respectively.     

Photorespiration in the context of Rubisco biochemistry,CO2 diffusion and metabolism

Photorespiratory metabolism is essential for plants to maintain functional photosynthesis in an oxygen‐containing environment. Because the oxygenation reaction of Rubisco is followed by the loss of previously fixed carbon, photorespiration is often considered a wasteful process and considerable efforts are aimed at minimizing the negative impact of photorespiration on the plant’s carbon uptake. However, the photorespiratory pathway has also many positive aspects, as it is well integrated within other metabolic processes, such as nitrogen assimilation and C₁ metabolism, and it is important for maintaining the redox balance of the plant. The overall effect of photorespiratory carbon loss on the net CO₂ fixation of the plant is also strongly influenced by the physiology of the leaf related to CO₂ diffusion. This review outlines the distinction between Rubisco oxygenation and photorespiratory CO₂ release as a basis to evaluate the costs and benefits of photorespiration.     

Processing of DNA Polymerase-Blocking Lesions during Genome Replication Is Spatially and Temporally Segregated from Replication Forks

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Gel mobility shift scanning of the acetate-inducible promoters fromNeurospora crassa reveals a common co-inducible DNA-binding protein

The promoter regions of four acetate-inducible genes ofNeurospora crassa, acu-3, acu-5, acu-8 andacu-9, have been sequenced. Using a scanning gel mobility shift assay particular DNA regions in each promoter have been shown specifically to bind partially purified protein extracted from acetate-induced mycelia. The protein-binding regions so defined have common sequence motifs, elements of which are similar to those required for acetate induction inAspergillus nidulans.     

影响心脏骤停患者心肺复苏成功率的因素分析

目的:分析我院心脏骤停患者心肺复苏的成功率,并探讨其影响因素。方法:选取198名行心肺复苏的心脏骤停患者为研究对象,实施心肺复苏,并记录患者一般情况、复苏开始时间和地点、复苏过程和复苏结局等多项指标,统计分析复苏效果。结果:1198名患者,72例取得最终复苏成功,心肺复苏成功率为36.4%;2不同年龄(=15.380,P0.001)、基础性疾病(x~2=11.465,P=0.043)、复苏开始时间(x~2=57.968,P0.001)、地点(x~2=61.384,P0.001)患者心肺复苏成功率差异有统计学意义,年龄16~60岁、非心血管疾病、心脏骤停5分钟内、院内开始心肺复苏者成功率较高;3复苏成功者和失败者复苏持续时间(t=-5.961,P0.001)和气道建立时间(t=-4.045,P=0.004)的差异具有统计学意义,成功者复苏持续时间要短于失败者,而气道建立时间要早于失败者。结论:快速建立人工气道,不盲目延长心肺复苏时间,提高心脏骤停患者心肺复苏的成功率。     

冠状动脉旁路移植患者围术期的BNP 水平变化及临床意义

目的:研究冠状动脉旁路移植手术后患者B型脑钠钛(BNP)水平变化规律及临床意义。方法:选取我院2014年6月到2015年6月间收治的冠状动脉旁路移植手术患者80名,根据患者心脏左心室射血分数(LVEF)分为A组(45%)和B组(≤45%),观察两组患者在不同时间的BNP水平,对比两患临床相关指标、及心房颤抖和心功能不全发生情况。结果:A组患者在血管活性物质使用量、呼吸机使用时间、监护室停留时间及心房颤抖和心功能不全发生率都明显小于B组,差异有统计学意义(P0.05);术后6h两组患者的BNP水平开始明显上升,在术后24h达到峰值,此后开始下降但仍维持较高水平,组内比较差异均有统计学意义(P0.05)。A组患者在术前及术后各个时间段内BNP水平均明显小于B组,组间比较比较均有统计学意义(P0.05)。结论:冠状动脉旁路移植患者围手术期BNP水平可以反应患者心脏功能状况,BNP水平越高表示患者心脏越差。     

Gap-filling and bypass at the replication fork are both active mechanisms for tolerance of low-dose ultraviolet-induced DNA damage in the human genome

Ultraviolet (UV)-induced DNA damage are removed by nucleotide excision repair (NER) or can be tolerated by specialized translesion synthesis (TLS) polymerases, such as Polη. TLS may act at stalled replication forks or through an S-phase independent gap-filling mechanism. After UVC irradiation, Polη-deficient (XP-V) human cells were arrested in early S-phase and exhibited both single-strand DNA (ssDNA) and prolonged replication fork stalling, as detected by DNA fiber assay. In contrast, NER deficiency in XP-C cells caused no apparent defect in S-phase progression despite the accumulation of ssDNA and a G2-phase arrest. These data indicate that while Polη is essential for DNA synthesis at ongoing damaged replication forks, NER deficiency might unmask the involvement of tolerance pathway through a gap-filling mechanism. ATR knock down by siRNA or caffeine addition provoked increased cell death in both XP-V and XP-C cells exposed to low-dose of UVC, underscoring the involvement of ATR/Chk1 pathway in both DNA damage tolerance mechanisms. We generated a unique human cell line deficient in XPC and Polη proteins, which exhibited both S- and G2-phase arrest after UVC irradiation, consistent with both single deficiencies. In these XP-C/Polη^KD cells, UVC-induced replicative intermediates may collapse into double-strand breaks, leading to cell death. In conclusion, both TLS at stalled replication forks and gap-filling are active mechanisms for the tolerance of UVC-induced DNA damage in human cells and the preference for one or another pathway depends on the cellular genotype.     

High fidelity and lesion bypass capability of human DNA polymerase δ

DNA polymerase δ (Pol δ) is one of the main replicative DNA polymerases in human cells and therefore is a critical determinant of the overall accuracy of DNA synthesis. Here we document the fidelity of a human Pol δ holoenzyme and systematically score the types of mutations that the enzyme generates in a forward mutation assay. We find that human Pol δ is highly accurate, catalyzing less than one nucleotide mis-insertion per 220,000 nucleotides polymerized. Inactivation of proofreading or mutation of a conserved active site residue significantly elevates the frequency of incorporation errors, demonstrating the contribution of both the base selection and proofreading domains to the overall accuracy of synthesis by Pol δ. The highly selective nature of the polymerase active site is also indicated by the stalling of Pol δ upon encountering multiple types of DNA lesions. However, DNA damage is not an absolute block to Pol δ progression. We propose that partial lesion bypass by Pol δ represents a balance between stalling to allow for repair of mutagenic lesions by specialized repair proteins and bypass of damage to allow for successful completion of DNA synthesis by Pol δ in the presence of weakly blocking DNA adducts.     

微创体外循环在机器人辅助下心脏手术中的应用

目的总结微创体外循环在机器人（AESOP3000）辅助下心脏手术中应用的管理和经验。方法2003年11月～2007年11月,共17例患者接受体外循环下机器人辅助心脏手术,其中房缺修补术10例、室缺修补术2例、二尖瓣置换术4例、二尖瓣成形术1例。右腹股沟做约3—4cm小切口,行股动静脉插管建立体外循环。结果术中转流平稳,血流动力学稳定,未附加颈内静脉引流,仅在个别病例中,采用股静脉引流管上加用暂时性动力负压引流,监测指标均在正常范围,无手术死亡和围手术期并发症。结论微创体外循环的应用是保证机器人辅助心脏手术顺利、成功的重要因素。