大白鼠减压缺氧性肺水肿的形态计量研究

实验采用形态计量方法探讨大白鼠模拟６ｋｍ减压缺氧、４、８和１２ｈ条件下间质性肺水肿（ＩＰＥ）和冷水游泳负荷后８ｋｍ减压缺氧３－６ｈ肺泡性肺水肿（ＡＰＥ）的发生情况。结果表明，６ｋｍ减压缺氧各组，肺细支气管动脉周围腔明显扩大，冷负荷后缺氧肺水肿的面积较单纯８ｋｍ减压缺氧组和单纯冷负荷后缺氧组有显著性差别。     

Prevalence and clinical significance of pleural effusion in patients with acute pulmonary embolism: a retrospective study

BackgroundPleural effusion is observed in a subset of patients with acute pulmonary embolism (APE) and may be linked to clinical outcome, but findings from previous studies have been inconsistent. This study aimed to investigate the prevalence and clinical significance of pleural effusion in Chinese patients with APE.MethodsClinical data from hospitalized patients with APE were retrospectively collected and the prevalence of pleural effusion was determined. The relationship between the presence of pleural effusion and clinical outcome of APE was analyzed by Cox proportional hazards regression and Kaplan-Meier survival analysis.ResultsThe study enrolled 635 patients with APE. The prevalence of pleural effusion was 57.01% (362/635). Patients with pleural effusion had significantly higher in-hospital mortality (9.9% vs. 4.8%, P<0.05) and longer length of hospital stay (LOS) (19.99 vs. 15.31 days, P<0.05) than whose without pleural effusion. However, pleural effusion was not an independent risk factor for in-hospital mortality in patients with APE by multivariate Cox proportional hazards regression analysis [hazard ratio (HR) =1.70, 95% confidence interval (CI): 0.73–3.92, P=0.216] and Kaplan–Meier survival analysis (P=0.174).ConclusionsPleural effusion is a frequent occurrence in patients with APE and therefore merits greater attention from clinicians; however, it is not an independent risk factor for in-hospital mortality.     

Apurinic/apyrimidinic endonuclease immunoreactivity in germ cells of experimental varicocele-induced rat testes

Increased germ cell apoptosis is related to oxidative DNA damage; therefore, we investigated whether there was a significant change in apurinic/apyrimidinic endonuclease (APE) in varicoceles. Experimental varicoceles were created by partial ligation of the left renal vein of adult male Sprague-Dawley rats, which were sacrificed at 1, 3 and 6 weeks after varicocele creation. Testicular tissues were sampled for TUNEL, Western blotting and immunohistochemistry. There was a significant increase in apoptotic germ cells in the ipsilateral testes 6 weeks after varicocele creation. Increased activation of p53, Bax and cleaved caspase-3 in the left testes was also noted. APE increased activation until 3 weeks after varicocele creation, and then decreased at 6 weeks after varicocele surgery. The spermatocytes were immunostained for both 8-hydroxy-2′-deoxyguanosine and APE, but the spermatogonia revealed only APE immunopositivity in the defective tubules. These results suggest that repression of APE is an underlying mechanism of augmented p53-dependent apoptosis in varicocele-induced rat testes and that remaining APE in the spermatogonia plays a decisive role in regaining testicular spermatogenic function after varicocelectomy.     

pSilence APE1提高骨肉瘤放疗敏感性的动物实验研究

目的:观察APE1 siRNA表达载体pSilence APE1基因放射治疗对骨肉瘤裸鼠移植瘤生长的抑制作用。方法:人骨肉瘤细胞9901荷瘤裸鼠30只随机分为3组:对照组、单独放射治疗组和pSilence APE1 放疗联合治疗组。实验治疗第15天处死动物,绘制肿瘤生长曲线,免疫组化SP法检测骨肉瘤细胞APE1蛋白的表达、骨肉瘤细胞的微血管密度和TUNEL法检测肿瘤细胞凋亡的情况。结果:pSilence APE1 放疗联合治疗组和对照组、单独放射治疗组的肿瘤大小存在显著性差异(P<0.05)。pSilence APE1 放疗联合治疗组肿瘤组织APE1表达显著降低;pSilence APE1 放疗联合治疗组肿瘤微血管密度明显低于对照组和单独放射治疗组(P<0.01),而肿瘤细胞凋亡显著增加(P<0.01)。结论:实验结果表明,pSilence APE1基因放射治疗能显著抑制骨肉瘤的生长。     

Is there a linkage between bioaccumulation and the effects of alkylphenols on male breams (Abramis brama)?

There was some evidence from a previous study that estrogenic disruptors, like alkylphenols, could effect fish in the small River Saar of Southwestern Germany. Concentrations of 4NP and 4NP1EO found in breams (Abramis brama) in the Saar River were much higher than those found in other sampling sites of the German Environmental Specimen Bank, including those from sampling sites in the Rivers Elbe, Rhine, Mulde, and Saale and in Lake Belau. We studied the relationship between accumulation and effect using vitellogenin (vtg) and a hepatosomatic index (HSI) of estrogenic effects and by measuring concentrations of AP and APE accumulated in breams caught at six sampling sites in the River Saar and one in the River Mosel. To link these results with those of the previous study we standardized our sampling efforts to obtain comparable data. Elevated vtg levels were found in the breams at all sampling sites near to or downstream of sewage plant discharges, whereas low vtg levels corresponded to sampling sites not influenced by municipal waste water. While HSI values did not correspond to the location of sampling sites, there was a weak but statistically significant correlation to vtg concentrations. Concentrations of four AP and APE were much more lower, as in the previous study, and were neither linked with sewage treatment plant discharges nor correlated with vtg levels. In conclusion, a linkage between accumulation and the effects of AP and APE could not be established, but the relationship between elevated vtg concentrations and municipal waste water, which contains other important endocrine disruptors, was clear.     

Expression levels of the DNA repair enzyme HAP1 do not correlate with the radiosensitivities of human or HAP1-transfected rat cell lines.

Apurinic/apyrimidinic (AP) sites in DNA are potentially lethal and mutagenic. They can arise spontaneously or following DNA damage from reactive oxygen species or alkylating agents, and they constitute a significant product of DNA damage following cellular exposure to ionizing radiation. The major AP endonuclease responsible for initiating the repair of these and other DNA lesions in human cells is HAP1, which also possesses a redox function. We have determined the cellular levels of this enzyme in 11 human tumour and fibroblast cell lines in relation to clonogenic survival following ionizing radiation. Cellular HAP1 levels and surviving fraction at 2 Gy (SF2) varied five- and tenfold respectively. However, no correlation was found between these two parameters following exposure to gamma-irradiation at low (1.1 cGy per min) or high (108 cGy per min) dose rates. To examine this further, wild-type and mutant versions of HAP1 were overexpressed, using an inducible HAP1 cDNA expression vector system, in the rat C6 glioma cell line which has low endogenous AP endonuclease activity. Induction of wild-type HAP1 expression caused a > fivefold increase in the capacity of cellular extracts to cleave an oligonucleotide substrate containing a single abasic site, but increased expression did not confer increased resistance to gamma-irradiation at high- or low-dose rates, or to the methylating agent methyl methanesulphonate (MMS). Expression in C6 cell lines of mutant forms of HAP1 deleted for either the redox activator or DNA repair functions displayed no apparent titrational or dominant negative effects. These studies suggest that the levels of endogenous AP endonuclease activities in the various cell lines examined are not limiting for efficient repair in cells following exposure to ionizing radiation or MMS. This contrasts with the correlation we have found between HAP1 levels and radiosensitivity in cervix carcinomas (Herring et al (1998) Br J Cancer 78: 1128-1133), indicating that HAP1 levels in this case assume a critical survival role and hence that established cell lines might not be a suitable model for such studies.     

Benzene-derived N-(4-hydroxyphenyl)-deoxyguanosine adduct: UvrABC incision and its conformation in DNA

Benzene, a ubiquitous human carcinogen, forms DNA adducts through its metabolites such as p-benzoquinone (p-BQ) and hydroquinone (HQ). N²-(4-Hydroxyphenyl)-2′-deoxyguanosine (N²-4-HOPh-dG) is the principal adduct identified in vivo by ³²P-postlabeling in cells or animals treated with p-BQ or HQ. To study its effect on repair specificity and replication fidelity, we recently synthesized defined oligonucleotides containing a site-specific adduct using phosphoramidite chemistry. We here report the repair of this adduct by Escherichia coli UvrABC complex, which performs the initial damage recognition and incision steps in the nucleotide excision repair (NER) pathway. We first showed that the p-BQ-treated plasmid was efficiently cleaved by the complex, indicating the formation of DNA lesions that are substrates for NER. Using a 40-mer substrate, we found that UvrABC incises the DNA strand containing N²-4-HOPh-dG in a dose- and time-dependent manner. The specificity of such repair was also compared with that of DNA glycosylases and damage-specific endonucleases of E. coli, both of which were found to have no detectable activity toward N²-4-HOPh-dG. To understand why this adduct is specifically recognized and processed by UvrABC, molecular modeling studies were performed. Analysis of molecular dynamics trajectories showed that stable G:C-like hydrogen bonding patterns of all three Watson–Crick hydrogen bonds are present within the N²-4-HOPh-G:C base pair, with the hydroxyphenyl ring at an almost planar position. In addition, N²-4-HOPh-dG has a tendency to form more stable stacking interactions than a normal G in B-type DNA. These conformational properties may be critical in differential recognition of this adduct by specific repair enzymes.     

吉西他滨对人胰腺癌Patu-8988细胞株APE/Ref-1的诱导作用

目的:研究人胰腺癌细胞株在吉西他滨化疗时APE/Ref-1基因表达的变化,并试图揭示其在胰腺癌化疗耐药中所起的作用.方法:不同浓度吉西他滨0、10、20、40及60μmol/L作用人胰腺癌Patu-8988细胞株24 h,分别以RT-PCR及Western blot方法测定作用后APE/Ref-1的mRNA及蛋白表达情况.结果:吉西他滨作用人胰腺癌Patu-8988细胞株24h后,APE/Ref-1的mRNA及蛋白表达水平明显上升,并与吉西他滨的浓度呈正相关(RT-PCR:r=0.645,P=0.012;Western blot:r= 0.598,P=0.020).结论:APE/Ref-1在胰腺癌化疗时表达明显增强,可能与化疗耐药性的产生有关,并提示针对APE/Ref-1的靶向干预可能有助于提高胰腺癌的化疗敏感性.