三种集约化种植体系氮素平衡及其对地下水硝酸盐含量的影响

选取中国北方3种重要的集约化种植体系小麦玉米轮作、大棚蔬菜和果园,研究了3种体系年度氮素输入输出关系、土壤硝酸盐的累积、不同体系地下水硝态氮含量的动态变化.结果表明,大棚蔬菜年度化肥氮、有机肥氮、灌水带入的氮和总氮输入量分别为135.8、1881、402和36.56kg·hm^-2,分别为小麦玉米田的25、37.5、83.8和5.8倍,为果园的2.1、10.4、6.82和4.2倍.不同系统降水输入的氮在142～189kg·hm^-2之间.3个体系氮输出量分别为280、329和121kg·hm^-2.氮素年度盈余分别为349、332.7和74.6kg·hm^-2.0～90cm土层硝态氮累积量分别为22.1～2.75、1173和613kg·hm^-2,90～180cm土层硝态氮累积量分别为2.13～2.42、10.32和976kg·hm^-2.在0～180cm剖面中,小麦玉米田各层土壤硝态氮处于相对均一分布,大棚蔬菜以表层最高,30cm以下各层也远高于大田,果园土壤硝态氮累积随土壤深度而增加.3种体系均表现出硝酸盐的明显淋洗.大棚蔬菜区浅井地下水硝态氮含量99%超过了10mg·L^-1.而大棚深井和果园浅井超标率均为5%,小麦玉米深井为1%.大棚蔬菜区地下水硝态氮含量与井深呈指数函数降低关系.     

重症患者急救插管预氧合的临床研究

目的:观察预氧合在ICU重症患者急救插管中的效果并探讨预氧合的最佳方式。方法:选择ICU内低氧血症成年危重患者28例,按入ICU顺序随机分为3组:A组(对照组,n=10),B组(气囊-面罩预氧合组,n=9)和C组(麻醉机-面罩预氧合组,n=9)。A组入室后即行快速气管插管,B组气囊-面罩预氧合5 min后行气管插管,氧流量为15 L/min。C组麻醉机-面罩预氧合5 min后行气管插管,氧流量为4 L/min。观察指标:持续脉搏血氧饱和度(SpO2),动脉血气分析及相关并发症。结果:三组在预氧合之前,各项基本指标比较无统计学差异。在预氧合后,B、C组的SpO2明显高于A组(P0.05);在插管后即刻,B、C组的SpO2也显著高于A组(P0.05),同时C组SpO2高于B组(P0.05)。血气分析中,预氧合后,C组的PaO2和SaO2均高于A、B组(P0.05);在插管后即刻,C组PaO2和SaO2高于A组,同时C组SaO2高于B组(P0.05)。并发症的比较上,C组的腹胀发生率明显低于B组(P0.05)。结论:ICU内急救插管前的预氧合能显著提高患者的血氧水平,效果明显好于直接气管插管;在预氧合的方式中,麻醉机-面罩的预氧合效果要优于常规使用的气囊-面罩,且并发症也较少。     

Mortality prediction by acute kidney injury biomarkers in comparison with serum creatinine

Abstract

Objectives: To investigate the performance of acute kidney injury (AKI) biomarkers for mortality prediction.

Materials and methods: Cutoff values of urinary L-type fatty acid-binding protein (L-FABP) and N-acetyl-β-d-glucosaminidase (NAG) for AKI diagnosis in ICU were determined in the derivation cohort. The performance of these AKI biomarkers for mortality prediction was evaluated in the validation cohort with stratification of serum-creatinine based AKI diagnosis.

Results: Mortality in the AKI patients diagnosed by serum creatinine was increased remarkably when urinary L-FABP and NAG were positive.

Conclusions: These AKI biomarkers can specifically detect high-risk patients among creatinine-base diagnosed AKI.     

Higher frequency of septic shock in septic patients with the 47C allele (rs4880) of the SOD2 gene

Aim

To analyze the effect of the two different versions of the manganese superoxide dismutase gene (SOD2) on sepsis. The SOD2 gene presents the 47C > T single nucleotide polymorphism (SNP; ID: rs4880) which produces MnSOD with different activities. The − 9Val MnSOD (47T allele) is less efficient than the − 9Ala version (47C allele). During sepsis there are abundance of ROS, high SOD2 expression and excess of H₂O₂ synthesis. High concentrations of H₂O₂ could affect the sepsis scenario and/or the sepsis outcome.

Methods

We determined the 47C > T single nucleotide polymorphism (SNP) frequencies in 529 critically ill patients with or without sepsis, facing outcome. To collect information on population frequencies, we obtained a pilot 47C > T genotypic and allelic frequencies in a random group of 139 healthy subjects.

Results

We compared the 47C allele carriers (47CC + 47CT genotypes) with 47TT homozygotes and noticed a significant association between 47C allele carriers and septic shock in septic patients (P = 0.025). With an adjusted binary multivariate logistic regression, incorporating 47C > T SNP and the main clinical predictors, we showed high SOFA scores [P < 0.001, OR = 9.107 (95% CI = 5.319–15.592)] and 47C allele [P = 0.011, OR = 2.125 (95% CI = 1.190–3.794)] were significantly associated with septic shock outcome. With this information we presented a hypothesis suggesting that this negative outcome from sepsis is possibly explained by effects on cellular stress caused by 47C allele.

Conclusion

In our population there was a significant higher frequency of septic shock in septic patients with the 47C allele of the SOD2 gene. This higher 47C allele frequency in septic patients with negative outcome could be explained by effects of higher activity MnSOD on cellular stress during the sepsis.     

Identification of MRI1, encoding translation initiation factor eIF-2B subunit alpha/beta/delta-like protein,as a candidate locus for infantile epilepsy with severe cystic degeneration of the brain

Several neurodegenerative disorders are known to predominantly affect the white matter of the brain including vanishing white matter disease (VWMD), an autosomal recessive disorder characterized by leukodystrophy of varying severity in addition to variable systemic involvement. We report a consanguineous Arab family with three affected children, all of whom presented with severe neonatal epilepsy and profound neurodegenerative disease characterized by marked leukodystrophy with white matter cavitation mimicking VWMD. We combined autozygome and exome analysis to identify a novel variant in the gene encoding a member of the eIF2B-related family of proteins (MRI1). This is a poorly understood family of proteins of unclear function. Our results represent the first link between a variant in a member of this family and a human disease, and suggest that it converges with the highly homologous eIF2B, known to be mutated in VWMD, on the molecular pathogenesis of neurodegeneration.     

区级医院重症监护病区耐甲氧西林金黄色葡萄球菌的调查和分析

目的通过对区级医院重症监护病区耐甲氧西林金黄色葡萄球菌(MRSA)感染的流行初期进行调查和分析,以防止MRSA的暴发流行以及能够采取有效治疗措施。方法对2006年12月至2007年1月区级医院重症监护病区患者、医务人员及物体上送检标本中被MRSA感染的病例进行调查和分析。结果从重症监护病区患者、工作人员及物体上采集标本MRSA的感染阳性率分别为25%~47.6%、0%和20%。结论此次有局部暴发趋势的MRSA感染由于发现及时、措施得当被控制住。医院必须加强监督抗生素的合理用药和耐药性的检测,严格医务人员洗手及实行消毒隔离措施,切断传播途径,防止MRSA感染在医院的发生和流行。     

ICU肾功能不全患者耐碳青酶烯类肺炎克雷伯菌的分布特征及耐药特性分析

目的:调查与分析重症监护病房(ICU,Intensive Care Unit)肾功能不全患者耐碳青酶烯类肺炎克雷伯菌的分布特征及耐药特性。方法:收集2015年2月到2017年12月入住我院ICU的合并肾功能不全的感染性患者标本46例,调查标本来源与患者的临床资料,分离鉴定病原菌并进行耐药特性分析。结果:46例患者中共分离出165株耐碳青酶烯类肺炎克雷伯菌,标本来源于尿液6例,痰液20例,血液4例,肺泡灌洗液10例,分泌物3例,胆汁3例。165株耐碳青酶烯类肺炎克雷伯菌对美罗培南、亚胺培南、厄他培南、头孢噻吩、头孢噻肟、氨苄西林、阿莫西林/克拉维酸、环丙沙星的耐药率在80%以上,对哌拉西林/他唑巴坦、庆大霉素的耐药率在75%左右,对米诺环素、四环素、替加环素的耐药率均在40%以下。46例患者中,治愈16例,好转17例,无效13例,总有效率为71.74%;ICU平均住院天数为(11.48±2.11)d;总住院天数为(45.29±1.48)d,院内病死11例,病死率为23.91%。多因素Logistic回归分析结果显示深静脉置管置入(OR=1.893)、年龄≥65岁(OR=2.154)、使用碳青霉烯类抗菌药物(OR=2.041)为ICU肾功不全患者发生耐碳青酶烯类肺炎克雷伯菌感染的独立危险因素(P0.05)。结论:ICU肾功不全患者耐碳青酶烯类肺炎克雷伯菌多来源于痰液标本,对米诺环素、四环素、替加环素的耐药性低,在临床上可以选择此类药物,合理把握用药的时间和剂量,增强抗感染的效率。同时,深静脉置管置入、年龄≥65岁、使用碳青霉烯类抗菌药物为治疗过程中主要的危险因素,在ICU肾功不全患者治疗中,应该重点考虑,提高治疗效率。     

重症监护病房呼吸机相关性肺炎病原学以及耐药性分析

目的:探讨重症监护病房呼吸机相关性肺炎病原学以及耐药性。方法:对我院2007年2月-2011年7月ICU内出现呼吸机相关性肺炎的患者99例作为研究对象,并对取痰液标本进行病原学以及耐药性分析。结果:革兰阴性菌的检出明显高于其他菌属,在G-杆菌中铜绿假单胞菌以及大肠埃希菌最为常见,G+球菌中以金黄色葡萄球菌以及肺炎链球菌最为常见;所有菌属均对常规抗菌药物有一定的耐药性,但其对万古霉素的敏感性仍然较高。结论:加强对ICU呼吸机相关肺炎进行分离致病菌并对其进行耐药性检测,以指导合理使用抗菌药物,有助于改善患者预后。     

外科ICU 中心静脉导管相关血流感染的回顾性病例对照研究

目的:了解外科ICU中心静脉导管相关血流感染(CRBSI)的发病率、病原菌分布及相关危险因素,为临床预防和经验性治疗提供依据。方法:回顾性调查我院外科ICU 2010年1月～2011年8月的中心静脉导管置管病例,根据血培养和导管培养结果分为CRBSI组和非CRBSI组,统计CRBSI的发病率、致病菌;比较CRBSI组与非CRBSI的临床资料,应用多因素Logistic回归分析筛查相关危险因素。结果:共收集249例中心静脉置管病例,CRBSI发病率为8.41例次/千导管日,病原菌分布为G+菌4例,G-菌9例,真菌8例。Logistic回归分析显示导管留置时间(OR 3.298,95%CI 1.070~10.168,P=0.038)、APACHEII评分(OR 1.137,95%CI 1.067~1.213,P=0.000)、完全胃肠外营养(OR 1.117,95%CI 1.023~1.219,P=0.014)是CRBSI的独立危险因素。结论:导管留置时间、APACHEII评分、完全胃肠外营养是发生CRBSI的独立危险因素。