无创通气不同呼吸界面对COPD患者的生理学影响

目的 探讨无创正压通气(NPPV)时不同呼吸界面对慢性阻塞性肺疾病(COPD)急性加重期并呼吸衰竭患者的生理学影响.方法 选择30例COPD急性加重期并呼吸衰竭患者.无创正压通气时患者随机先后接受不同呼吸界面(面罩、鼻罩和鼻塞).动态观察不同呼吸界面时患者呼吸方式、血气分析和对呼吸界面耐受性等的差异.结果 (1)与自主呼吸相比,无创正压通气时三种不同呼吸界面均可改善患者的潮气量、分钟通气量和呼吸频率(P＜0.01),三种不同呼吸界面时的呼吸频率相似(P＞0.05),但面罩时的潮气量和分钟通气量比鼻罩时更高(P＜0.05);(2)与自主呼吸相比,无创正压通气时三种不同呼吸界面均可改善患者的动脉血气(P＜0.05),面罩和鼻塞时的PCO2比鼻罩时更低(P＜0.05);(3)患者均可耐受三种不同的呼吸界面,但患者对鼻罩的耐受性比面罩和鼻塞更好(P＜0.01).结论 本生理学研究证实了无创正压通气可改善COPD急性加重期并呼吸衰竭患者的呼吸方式和动脉血气,面罩和鼻塞时的疗效更佳,而鼻罩时的耐受性更好.     

Fluctuating PEEP (F–PEEP) versus conventional PEEP in dogs with asymmetrical lung injury

Fluctuating PEEP (F-PEEP) is a newly developed PEEP in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with unilateral lung injury induced by the introduction of hydrochloric acid, F-PEEP in which the EEP was periodically changed from 0.5 to 1.5 kPa at periods of 6 min, and conventional PEEP (C-PEEP) with an optimized EEP of 1.0 kPa, were each applied for 30 min. F-PEEP produced a significantly greater improvement of PaO2 and intrapulmonary shunt (QS/QT) than C-PEEP, and at the low EEP phase, the greatest improvement accompanied by an increased dynamic compliance and a large cardiac output was obtained. These results suggest that F-PEEP provides a useful mode of artificial ventilation for the treatment of unilateral lung injury.     

Immunoglobulin heavy chain Diversity genes rearrangement pattern indicates that MALT-type gastric lymphoma B cells have undergone an antigen selection process

Gastric MALT lymphoma usually develops from chronic gastritis, the vast majority of which (>90%) is associated with Helicobacter pylori infection. We sequenced the third complementarity determining region (CDR3) of immunoglobulin heavy chain genes in 19 gastric MALT lymphoma clones to determine the pattern of variable (V), diversity (D) and joining (J) gene utilization during immunoglobulin gene rearrangement.
DNA was extracted from paraffin-embedded sections and the rearranged CDR3 regions were amplified using a semi-nested polymerase chain reaction (with primers complementary to the conserved framework-three segment of the variable region [FR3A] and J regions). The DNA used for cloning and sequencing was obtained after purification of monoclonal bands excised from polyacrylamide gels. The N-D-N region specific to each clone was compared with known germline D sequences.
Similarly to that observed in normal and leukaemic B cells, our series of gastric MALT lymphomas showed apparent preferential utilization of genes from the DXP family. In two cases no similarity between the CDR3 nucleotide sequences of the neoplastic clones and the known germline D sequences could be found. In 10/19 analysed alleles the lymphoma B-cell clones appeared to contain two D gene segments (D-D recombination), a rare occurrence in normal individuals but one which has been described as a significant event in the determination of idiotype expression and antigen-binding affinity. Remarkably, despite the use of different D and J segments, the resultant amino acid sequences matched in two patients, suggesting the presence of a common selecting antigen.
The observed pattern of D gene rearrangement suggests that MALT lymphoma B-cell clones have undergone antigen selection, which seems to indicate that the antigen stimulation plays a pivotal role in the development of the lymphoma.     

Optimal Selection of Sib Pairs from Random Samples for Linkage Analysis of a QTL Using the EDAC Test

Percentages of extremely concordant and extremely discordant sib pairs are calculated that maximize the power to detect a quantitative trait locus (QTL) under a variety of circumstances using the EDAC test. We assume a large fixed number of randomly sampled sib pairs, such as one would hope to find in the large twin registries, and limited resources to genotype a certain number of selected sib pairs. Our aim is to investigate whether optimal selection can be achieved when prior knowledge concerning the QTL gene action, QTL allele frequency, QTL effect size, and background (residual) sib correlation is limited or absent. To this end we calculate the best selection percentages for a large number of models, which differ in QTL gene action allele frequency, background correlation, and QTL effect size. By averaging these percentages over gene action, over allele frequency, over gene action, and over allele frequencies, we arrive at general recommendations concerning selection percentages. The soundness of these recommendations is subsequently in a number of test cases.     

Laboratory screening method for selection of healthy volunteers

The aim of laboratory screening in Phase I is to exclude subjects with subclinical illness, who might be at increased risk in the study, and who might also adversely influence interpretation of the results. A new method for laboratory screening, based on Bayesian probability theory, is proposed, which consists of: 1. Drawing up a list of diseases to be excluded. 2. Defining for each disease, the maximum acceptable risk that an included subject could be affected by it. 3. Identifying one test for each disease. 4. Using a contingency table to calculate the specificity of the test and integrating the estimated prevalence of the disease from epidemiological data. 5. Applying the percentage obtained by the calculation of specificity to the previously determined distribution of values in the volunteer population to identify the threshold value for inclusion. Use of this deductive method in screening volunteers for Phase I trials affords increased security of selection, while reducing the number of non-pertinent exclusions because of laboratory findings.     

Conditional estimation of sensitivity and specificity from a phase 2 biomarker study allowing early termination for futility

Development of a disease screening biomarker involves several phases. In phase 2 its sensitivity and specificity is compared with established thresholds for minimally acceptable performance. Since we anticipate that most candidate markers will not prove to be useful and availability of specimens and funding is limited, early termination of a study is appropriate, if accumulating data indicate that the marker is inadequate. Yet, for markers that complete phase 2, we seek estimates of sensitivity and specificity to proceed with the design of subsequent phase 3 studies. We suggest early stopping criteria and estimation procedures that adjust for bias caused by the early termination option. An important aspect of our approach is to focus on properties of estimates conditional on reaching full study enrollment. We propose the conditional‐UMVUE and contrast it with other estimates, including naïve estimators, the well‐studied unconditional‐UMVUE and the mean and median Whitehead‐adjusted estimators. The conditional‐UMVUE appears to be a very good choice. Copyright © 2008 John Wiley & Sons, Ltd.     

优选前后精子顶体酶活性与IVF受精率相关性的研究

目的探讨优选处理前和处理后精子顶体酶活性的变化,及与体外受精(IVF)受精率的相关性。方法采用分光光度比色法,对接受IVF治疗的53例不育夫妇男方精液,分别测定优选处理前和处理后精子顶体酶活性,分析其与IVF受精率的相关性。结果优选处理后精子顶体酶活性与优选前比较有显著性差异(P<0.05);达到常规IVF标准并选择常规IVF治疗者,优选后的精子顶体酶活性与IVF受精率有相关性,精子顶体酶活性降低与IVF受精率降低有关。结论精子顶体酶活性与IVF受精率有相关性,并且通过精子顶体酶活性可以预测IVF受精率。     

电脑比配色仪与比色板之间的相近性分析

目的：通过对比色记录的分析，比较Vita比色板、松风Vintage Halo比色板和电脑比配色仪之间的相近性和差异性。方法：随机抽取100名年龄在21～24岁的本地在校大学生，由男女两位测试者使用电脑比配色仪、Vita比色板和松风Vintage Halo比色板对被测试者的左上中切牙进行比色分析。结果：三种比色方法均以A色调最为集中，占总数的55％以上。其次是D色调占总数20％以上。男女测试者的选色在A、R、VR．系列中无明显差异。结论：电脑比配色仪、Vita比色板、松风Vintage Halo比色板均不能完全覆盖本地区青年天然中切牙的色度特征，只在A色调系列中重复率较高。     

实验性隐睾术后大鼠附睾的反应性变化

本研究描述了实验性隐睾术后大鼠附睾的形态学变化。结果表明,隐睾术后由于腹温作用和附皋管管腔内容物的改变,附睾管上皮细胞的形态和功能明显改变。术后早期上皮细胞出现无丝分裂相,上皮细胞的分泌和吞噬功能加强,胞质内含PAS阳性颗粒的细胞增多。随术后时间的延长,附睾上皮细胞变化逐渐趋于稳定。[