心室晚电位的时间－频率表示法的进一步改进

在心室晚电位的研究中，我们引入了信号的时间一频率表示法，并根据晚电位的具体特性用Ｗｉｇｎｅｒ分布法（维格纳分布）把信号表示为在时间及频率空间中的能量分布。由于Ｗｉｇｎｅｒ分布的优异性质使我们有可能更准确表示出心室晚电位的存在。但当输入信号是两个信号的线性叠加时，Ｗｉｇｎｅｒ分布的结果会出现一个交叉项，相当于引入干扰。针对此不足，作者介绍改进方案，消除部分交叉项，收到较好的效果，并给出一些仿真及应用实例。     

人缺血脑组织中TNF-α和IL-1β的表达

目的 :检测人缺血脑组织中TNF α和IL 1β的表达。 方法 :将 13例脑梗死的死亡病例按发病时间分成 <2d、3～ 5d、 >5d3个组 ,以非缺血侧半球作为对照 ,用免疫组化染色法检测缺血脑组织中TNF α和IL 1β的表达。结果 :人脑缺血后缺血病灶中TNF α和IL 1β呈高表达 ,与正常侧脑组织相比较有极显著差异。TNF α和IL 1β表达细胞的分布与缺血灶相一致 ,呈局灶性分布。TNF α的表达高峰在病后 2d内。IL 1β表达高峰在病后 3～ 5d。在病后 5d ,缺血侧TNF α和IL 1β的表达与正常侧无显著差异。结论 :人类脑缺血组织中TNF α和IL 1β的表达与动物实验的结果相似 ,提示TNF α和IL 1β参与了脑缺血损伤 ,有助于临床建立新的有针对性的治疗措施     

Antifouling blood purification membrane composed of cellulose acetate and phospholipid polymer

The ideal surface of an artificial blood purification membrane needs hemocompatibility and durability of high performance; it should not adsorb any proteins or cells but should still have high permeability in the desired range of solute size. To improve the anti-fouling property of cellulose acetate (CA) membranes, a CA membrane blended with poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (BMA)) (PMB30) was designed as a blood purification membrane. The polymer solutions for preparing the membrane were prepared using a solvent mixture composed of N, N-dimethylformamide, acetone, 2-propanol or water. The CA and CA/PMB30 blend membranes with an asymmetric and porous structure were prepared by a phase inversion process.The characteristics of the CA/PMB30 blend membrane, such as structural properties, mechanical properties, and solute permeability were examined with attention to changes in the preparation conditions of the membrane. The CA/PMB30 blend membrane had good water and solute permeability and a sharp molecular weight cut-off property. Moreover, the amount of proteins adsorbed on the CA/PMB30 blend membrane surface was less than that of the original CA membrane and a conventional polysulfone membrane. Adhesion and activation of platelets on the CA/PMB30 blend membrane were reduced compared with that on a CA membrane. In addition, the CA/PMB30 blend membrane showed good permselectivity and an antifouling property during a long time ultrafiltration experiment with protein solutions.     

Contribution of the twin arginine translocation system to the virulence of enterohemorrhagic Escherichia coli O157:H7

Shiga toxin-producing Escherichia coli O157:H7 is a major food-borne infectious pathogen. In order to analyze the contribution of the twin arginine translocation (TAT) system to the virulence of E. coli O157:H7, we deleted the tatABC genes of the O157:H7 EDL933 reference strain. The mutant displayed attenuated toxicity on Vero cells and completely lost motility on soft agar plates. Further analyses revealed that the ΔtatABC mutation impaired the secretion of the Shiga toxin 1 (Stx1) and abolished the synthesis of H7 flagellin, which are two major known virulence factors of enterohemorrhagic E. coli O157:H7. Expression of the EDL933 stxAB₁ genes in E. coli K-12 conferred verotoxicity on this nonpathogenic strain. Remarkably, cytotoxicity assay and immunoblot analysis showed, for the first time, an accumulation of the holotoxin complex in the periplasm of the wild-type strain and that a much smaller amount of StxA₁ and reduced verotoxicity were detected in the ΔtatC mutant cells. Together, these results establish that the TAT system of E. coli O157:H7 is an important virulence determinant of this enterohemorrhagic pathogen.     

肺淋巴管平滑肌瘤病临床病理学观察

目的 探讨肺淋巴管平滑肌瘤病临床、病理特征。方法 对5例肺淋巴管平滑肌瘤病临床资料进行收集分析,HE切片观察,采用免疫组织化学(SP法)检测平滑肌肌动蛋白(SMA)、HMB45、基质金属蛋白酶(MMP)2、孕激素受体(PR)、雌激素受体(ER),并进行文献复习。结果 肺淋巴管平滑肌瘤病是原因不明的肺部疾病,只发生在女性,特别是绝经前妇女。临床表现为呼吸困难,咯血,气胸和乳糜胸等。病理学检查显示不同成熟度平滑肌细胞在细支气管壁、肺泡壁、淋巴管壁和血管壁周围增生,肺实质呈囊性变。增生的平滑肌细胞免疫组织化学5例SMA、HMB45、MMP2均阳性;1例的ER和PR均阳性,1例仅ER阳性,1例仅PR阳性,1例的ER和PR均阴性。结论 育龄期妇女如反复出现自发性气胸、咯血、活动后呼吸困难应考虑肺淋巴管平滑肌瘤病的可能,病理检查可确定肺淋巴管平滑肌瘤病的诊断。     

CD2 and other surface molecules in the regulation of non-MHC-restricted cytolytic function.

The effect of anti-CD2 and Fc receptor binding molecules on the cytolytic function of a highly enriched population of CD3- large granular lymphocytes (LGL) was studied. These cells could mediate natural killer (NK) activity, antibody-dependent cellular cytotoxicity (ADCC) and lectin-dependent cellular cytotoxicity (LDCC). Both ADCC and LDCC were enhanced by anti-CD2. The enhanced LDCC could also be observed with IL-2-activated LGL. However, NK cell activity was usually slightly diminished or unaffected by anti-CD2 binding. Immune complex and aggregated human IgG had no effect on ADCC but an anti-CD16 showed a dose-dependent inhibition of ADCC, reversible by anti-HLA-ABC and anti-CD2. Cross-linking of LGL surface-bound anti-CD2 caused an almost complete inhibition of LDCC and ADCC but had much less effect on NK activity. These experiments show that ADCC and LDCC mediated by CD3- LGL can be influenced by perturbing the CD2 molecule. NK activity was, however, affected differently, suggesting some basic differences in the pathway of ADCC and NK function.     

皮肤扩张术修复头皮合并颅骨缺损

目的探讨头皮合并颅骨缺损的修复方法。方法对2000年至2007年治疗的6例头皮合并颅骨缺损患者，采用皮肤扩张术修复头皮，钛网修补颅骨缺损。结果6例患者中，1例患者出现皮瓣下积液，经抽吸、加压包扎后愈合；其余病例未出现感染、血肿及皮瓣坏死等并发症，外观满意。结论皮肤扩张术和钛网联合应用是修复头皮合并颅骨缺损的较好方法。     

Sequence analysis of cDNAs for the human and bovine ATP synthase β subunit: mitochondrial DNA genes sustain seventeen times more mutations

We have cloned and sequenced human and bovine cDNAs for the subunit of the ATP synthase (ATP-synß), a nuclear DNA (nDNA) encoded oxidative phosphorylation (OXPHOS) gene. The two cDNAs were found to share 99% amino acid homology and 94% nucleotide homology. The evolutionary rate of ATPsynß was then compared with that of two mitochondrial DNA (mtDNA) ATP synthase genes (ATPase 6 and 8), seven other mtDNA OXPHOS genes, and a number of nuclear genes. The synonymous substitution rate for ATPsynß proved to be 1.9 × 10^–9 substitutions per site per year (substitutions × site^–1 × year^–1) (SSY). This is less than 1/2 that of the average nDNA gene, 1/12 the rate of ATPase 6 and 8, and 1/17 the rate of the average mtDNA gene. The synonymous and replacement substitution rates were used to calculate a new parameter, the selective constraint ratio. This revealed that even the most variable mtDNA protein was more constrained than the average nDNA protein. Thus, the high substitution mutation rate and strong selective constraints of mammalian mtDNA proteins suggest that mtDNA mutations may result in a disproportionately large number of human hereditary diseases of OXPHOS.