Quantitative evaluation of recall and precision of CAT Crawler,a search engine specialized on retrieval of Critically Appraised Topics

Background

Critically Appraised Topics (CATs) are a useful tool that helps physicians to make clinical decisions as the healthcare moves towards the practice of Evidence-Based Medicine (EBM). The fast growing World Wide Web has provided a place for physicians to share their appraised topics online, but an increasing amount of time is needed to find a particular topic within such a rich repository.

Methods

A web-based application, namely the CAT Crawler, was developed by Singapore's Bioinformatics Institute to allow physicians to adequately access available appraised topics on the Internet. A meta-search engine, as the core component of the application, finds relevant topics following keyword input. The primary objective of the work presented here is to evaluate the quantity and quality of search results obtained from the meta-search engine of the CAT Crawler by comparing them with those obtained from two individual CAT search engines. From the CAT libraries at these two sites, all possible keywords were extracted using a keyword extractor. Of those common to both libraries, ten were randomly chosen for evaluation. All ten were submitted to the two search engines individually, and through the meta-search engine of the CAT Crawler. Search results were evaluated for relevance both by medical amateurs and professionals, and the respective recall and precision were calculated.

Results

While achieving an identical recall, the meta-search engine showed a precision of 77.26% (±14.45) compared to the individual search engines' 52.65% (±12.0) (p < 0.001).

Conclusion

The results demonstrate the validity of the CAT Crawler meta-search engine approach. The improved precision due to inherent filters underlines the practical usefulness of this tool for clinicians.

     

Butyrate increases production of human chimeric IgG in CHO-K1 cells whilst maintaining function and glycoform profile

The influence of sodium butyrate on the production and glycosylation of recombinant mouse/human chimeric antibody by transfected CHO-K1 cells was investigated. We selected cells expressing 'wild-type' antibody with a human IgG3 heavy chain and a mutant of this molecule in which Phe 243 is replaced by Ala. These proteins have previously been shown to exhibit very different glycoform profiles with the mutant IgG being comprised of glycoforms having a high galactose and sialic acid content. Cell culture with 0-5 mM butyrate was shown to effect a 2-4-fold increase in antibody production whilst the induction of apoptosis was observed in a dose-dependent manner. The optimal butyrate concentration was observed to be 2 mM. The glycoform profile of each antibody produced in the presence of butyrate was analyzed by HPAEC-PAD and shown to be unchanged, relative to that produced in the absence of butyrate. Biological activity was evaluated by the ability of the antibodies to trigger superoxide generation, through Fc gamma RI, and shown to be independent of production in the presence or absence of butyrate. A similar increase in production was observed for a high antibody-producing cell line when expanded in a hollow fibre bioreactor under low-serum conditions (1%). These results demonstrated that butyrate is of value for increasing the productivity of CHO-K1 for recombinant IgG and does not compromise either glycosylation or biological activity.     

肝脏血管瘤的手术指征和手术方法选择（附46例报告）

目的 探讨肝脏血管瘤的手术指征和手术方法。方法 回顾性分析采用手术治疗46例肝脏血管瘤病人资料，判断其手术指征，评价不同手术方法的治疗效果厦其手术并发症发生情况。结果 46例病人中，19例采用肝叶或肝段切除术，17例出现并发症，以胸腔积液和膈下积液多见，采用血管瘤摘除术的27例病人无并发症。结论 对肝脏血管瘤直径大于5cm并有明显临床症状，或不能除外恶性肿瘤的病人可以采用手术治疗。血管瘤摘除术是安全有效、并发症少的手术方法。     

腓浅神经痛诊治的解剖学基础(系列介绍之十五)

目的 介绍腓浅神经痛的诊断与局部注射的治疗方法。方法 选择门诊确诊为腓浅神经痛的患者18例，采用强的松龙混悬液加麻药局部注射神经穿出小腿深筋膜的部分的治疗方法。结果 所有病例皆在注射后短时完全止痛，多数病例一周后痊愈，少数病例经1～3次注射后痊愈。结论 对诊断明确的病例，采取强的松龙局部注射法，可以获得满意的疗效。     

腹膜透析治疗老年慢性肾功能衰竭的临床分析

目的 分析持续性腹膜透析(PD)治疗老年慢性肾功能衰竭(CRF)患者的临床效果,探讨PD在老年CRF患者中的应用经验.方法 回顾性分析89例老年CRF患者接受PD(简称老年PD组)治疗后的临床表现和生化指标、主要并发症、存活率、死亡原因等,并与53例非老年PD组相比较.结果 老年PD组的原发疾病以糖尿病(37.08%)、原发性高血压(30.34%)为主,而非老年PD组则以肾小球肾炎(54.72%)为主.两组患者的1年与3年存活率差异无统计学意义,腹膜炎仍是两组患者退出PD的主要原因.老年组的病死率明显高于非老年组,感染与心脑血管病是两组患者的主要并发症和死亡原因.低钾血症在老年PD患者中非常普遍.结论 腹膜透析在老年CRF患者的治疗中有效,但长期存活仍受腹膜炎、心脑血管病并发症的影响,老年PD患者的低钾血症应引起足够的重视.     

肿瘤光动力治疗中组织氧含量的动态模型研究

目的：分析肿瘤光动力治疗中的组织氧含量的变化规律，研究影响肿瘤光动力治疗效果的与氧相关的因素,探讨改进光动力治疗的途径。方法：建立肿瘤光动力治疗中氧含量的动态模型，并采用Crank—Nicolson离散方法解析该模型，在时间域和空间域上，分析光动力过程中肿瘤氧含量的动态变化过程，研究光照的光功率密度、肿瘤初始氧含量等因素对光动力疗效的影响，并比较间断光照和连续光照两种方式的不同疗效。结果：肿瘤氧含量随着治疗时间和离血管的距离呈衰减趋势，光动力反应只发生在血管附近的有限区域，且区域大小与初始氧含量密切相关．在较高的初始氧含量下，更大区域的氧含量因为处于阈值Cth以上，所以能发生光动力反应。当采用较低的光功率密度光照治疗时,肿瘤氧含量衰减比高功率密度下慢；当采用间断光照进行光动力治疗时，在治疗黑暗期肿瘤氧含量能得到回升．有利于光照期的治疗。结论：初始氧含量较高的情况下治疗效果更好；在较低的光功率密度下，光动力反应较难进行，但是有利于保护肿瘤供氧源的工作。在较低的初始氧含量下，间断光照方式的疗效要比连续光照要好。     

EB病毒LMP2A特异性CTL的体外诱导及分析

用EBV LMP2A重组痘苗病毒 (rVV LMP2A )转染人树突状细胞 (DC ) ,转染后的DC分别在第 1、 7、 14天刺激相同MHC背景的T细胞 ,在IL 2作用下诱导LMP2A特异性CTL。用LDH释放法检测CTL杀伤活性 ;流式细胞术 (FACS )检测CTL诱导分化过程中CD3+ 、CD4 + 、CD8+ 、CD5 6 + 等细胞的分群变化 ;RT PCR检测细胞分化过程中FasLmRNA表达 ;生物活性法检测功能性细胞因子IFN γ的分泌。结果显示本法诱导的CTL对靶细胞有特异性杀伤活性 ,第 2次和第 3次DC刺激后杀伤活性有所上升 ;在CTL诱导分化的第 7、 14、 2 1天细胞分群以CD4 + 、CD8+ 细胞为主 ;RT PCR证实所诱导的细胞内有FasLmRNA的表达 ;随细胞培养天数的增加IFN γ分泌增加 ,在第 14天达到较高水平。研究表明重组痘苗病毒载体rVV LMP2A转染的DC刺激T细胞可诱导出EBV LMP2A特异性CTL。     

涎腺癌肉瘤临床及病理分析

目的：探讨涎腺癌肉瘤的临床病理学特点及其鉴别诊断。方法：对3例涎腺癌肉瘤患者的临床资料进行回顾性研究并复习相关文献，对全部病例的组织学标本重新进行镜下观察。结果：涎腺癌肉瘤临床表现常为迅速增大的颜面部肿物并伴疼豢。光匀下组织学观察常可见肉瘤和癌两种成分并存，癌多为鳞状细胞癌和腺癌，肉瘤以骨或软骨肉瘤为主。结论：涎腺癌肉瘤的临床特点与涎腺其他恶性肿瘤较难区别，但涎腺癌肉瘤的恶性程度极高。