急性心力衰竭应用BiPAP 呼吸机疗效分析

目的:分析急性心力衰竭(AHF)患者应用双水平正压通气(BiPAP)呼吸机治疗的效应。方法:95例急性左心衰竭患者随机分为:A组(应用BiPAP呼吸机治疗)43例和B组(对照组,常规治疗)52例。A组在常规药物治疗的基础上,每天应用BiPAP呼吸机无创通气12～24小时,全部用鼻罩;B组仅应用常规药物治疗。疗程均为5天。观察两组治疗前后临床疗效、B型利钠肽(BNP)、血气分析及心功能的变化。结果:显效率:BiPAP组69.8%,对照组46.2%,两组有显著差异(P<0.05)。两组心功能、BNP、血气分析,治疗后与治疗前相比均有显著差异(P<0.05),治疗后BiPAP组与对照组间比较有显著差异(P<0.05)。结论:BiPAP呼吸机能改善急性左心衰竭患者的症状、血气结果及心功能,还能降低BNP。     

Periodic response to periodic forcing of the Droop equations for phytoplankton growth

The dynamics of a phytoplankton population growing in a chemostat under a periodic supply of nutrients is investigated with the model proposed by Droop. This model differs from the well-known Monod equations by incorporating nutrient storage by the cells. In spite of its nonlinearity and the time delays introduced by an internal nutrient pool, the model predicts a simple response to a periodic nutrient supply. The population is shown to oscillate with the same frequency as the forcing. To prove the existence of a periodic solution local and global bifurcation results are used. This work establishes a basis on which to evaluate experimental data against the model as a representation of the nutrient-phytoplankton interaction when nutrients fluctuate.     

Construction, Characterization, and Chromosomal Mapping of a Fosmid Library of the White-Cheeked Gibbon （Nomascus leucogenys）

Gibbons have experienced extensive karyotype rearrangements during evolution and represent an ideal model for studying the underlying molecular mechanism of evolutionary chromosomal rearrangements. It is anticipated that the cloning and sequence characterization of evolutionary chromosomal breakpoints will provide vital insights into the molecular force that has driven such a radical karyotype reshuffle in gibbons. We constructed and characterized a high-quality fosmid li- brary of the white-cheeked gibbon (Nomascus leucogenys) containing 192,000 non- redundant clones with an average insert size of 38 kb and 2.5-fold genome coverage. By end sequencing of 100 randomly selected fosmid clones, we generated 196 se- quence tags for the library. These end-sequenced fosmid clones were then mapped onto the chromosomes of the white-cheeked gibbon by fluorescence in situ hy- bridization, and no spurious chimeric clone was detected. BLAST search against the human genome showed a good correlation between the number of hit clones and the number of chromosomes, an indication of unbiased chromosomal distribu- tion of the fosmid library. The chromosomal distribution of the mapped clones is also consistent with the BLAST search result against human and white-cheeked gibbon genomes. The fosmid library and the mapped clones will serve as a valu- able resource for further studying gibbons' chromosomal rearrangements and the underlying molecular mechanism as well as for comparative genomic study in the lesser apes.     

Estimation of disease severity in the NHS cervical screening programme. Part II: quantitative methods of estimating disease severity and progression potential

R. G. Blanks Estimation of disease severity in the NHS cervical screening programme. Part II: quantitative methods of estimating disease severity and progression potential Objective: This is the second of a two‐part paper exploring the use of a more quantitative approach to both cytology and histology disease severity measurements. In Part I the problem of artificial cut‐off points was discussed and a semi‐quantitative solution to the problem proposed. In Part II quantitative methods are proposed that are used to predict the estimated progression probability (EPP) to invasive cancer. Methods: Based on models derived from published data the grade number (GN) is related to the EPP to invasive cancer over the next 10 years for both cytology (CEPP) and histology (HEPP) using a look‐up table. CEPP and HEPP are then adjusted by other factors such as age, persistence, HPV result, number of cells and lesion size to obtain the adjusted CEPP and HEPP (ACEPP and (AHEPP). The two factors can be combined to produce an adjusted weighted estimated progression potential using the formula AWEPP ((ACEPP + AHEPP)/2) × AHEPP) using a two to one bias in favour of the histology. Results: As an example of the methodology consider a slide estimated as showing a 60% probability of moderate dyskaryosis (HSIL favouring CIN2) and 40% probability of mild dyskaryosis (LSIL favouring CIN1). The GN number would be 1.6 (as described in Part I) and the EPP over the next 10 years 0.78%. For a woman aged 52 years (correction factor ×2.0) with a second mildly dyskaryotic smear (correction factor ×1.25) and >50 dyskaryotic cells (correction factor 1.5) the ACEPP would be 0.78 × 2.00 × 1.25 × 1.5 = 2.9%. If the HEPP on histology was 50:50 between CIN1 and CIN2, the AHEPP can be calculated as 1.4%. The AWEPP would be ((2.9 + 1.4)/2 × 1.4) = 1.7%. The final estimate of disease progression potential based on both cytology and histology is 1.7% over 10 years. Conclusions: These quantitative approaches based on adjusted and weighted EPP provide a framework suitable for research, audit and comparison between screening centres, and for tailoring criteria for colposcopy referral and treatment. Further research is required to improve the estimates given in the paper.     

325例腹腔镜附件手术的临床分析

目的:评价腹腔镜在附件疾病治疗中的价值及安全性。方法:回顾性分析325例附件良性疾病腹腔镜手术治疗情况。随机选取妇科附件良性肿瘤、异位妊娠、输卵管粘连及伞端不通、卵巢破裂、巧克力囊肿,卵巢冠囊肿等病例;采用腹腔镜手术治疗。术式根据病情不同,采取卵巢(冠)囊肿剥除术、附件切除术、输卵管切除术及造口术。结果:腹腔镜手术占同期手术42．54%,手术成功率100%,发生并发症5例(1．54%)。结论:腹腔镜微创手术,副作用少,适应证掌握得当,妇科大部分附件手术可在腹腔镜下完成。     

Prevalence of HIV Indeterminate Western Blot Tests and Follow-up of HIV Antibody Sero-Conversion in Southeastern China

HIV-indeterminate Western blotting(WB) results are typically obtained in WB confirmatory assays, and the number of indeterminate samples may increase with the detection of HIV infections, which will present considerable challenges for the management of HIV/AIDS. Nucleic acid detection has been used as a laboratory test for screening suspected or indeterminate samples. However, the effectiveness of these assays for the differential diagnosis of HIV-indeterminate WB samples remained undetermined. In this study, 210 subjects with HIV-indeterminate WB results were detected from 6360 positive HIV screening samples between 2015 and 2016 in southeastern China, in which HIV-indeterminate WB results accounted for 3.30%. The highest proportion of indeterminate results was observed in pregnant and lying-in women receiving physical examinations(16.67%), followed by that in voluntary blood donors(8.82%). The most common WB band patterns were p24, gp160 and p24, and gp160. The follow-up study revealed that the highest negative and positive conversion rates of HIV antibodies were in samples with a single p24 band(80.28%), and with gp160 and p24 bands(86.21%), respectively. Among the Env, Gag, and Pol antibodies, samples with a Gag band showed the highest negative conversion rate(81.25%), whereas the highest positive conversion rate was observed in samples with an Env band(56.76%). In addition, quantitative and qualitative HIV nucleic acid testing exhibited the highest sensitivity(96.3%) and specificity(97.85%), respectively. Our results indicate a lower proportion of HIV indeterminate WB results in southeastern China compared to previous reports, and the follow-up re-examination of patients with HIV indeterminate results should be performed. Nucleic acid testing facilitates the identification of HIV infections.     

利用结核分枝杆菌抗原特异性γ-IFN体外释放测定评估抗结核治疗疗效的临床应用价值

探讨利用结核分枝杆菌抗原特异性γ-IFN体外释放测定评估抗结核治疗疗效的临床应用价值。研究了66例培养阳性肺结核病人抗结核治疗过程中抗原特异性γ-IFN体外释放测定结果的变化,并与结核菌素皮试结果的变化相比较。结果,抗原特异性γ-IFN体外释放测定于抗结核治疗前期(满2个月)的阳性率显著高于后期(疗程满6个月)[55/66(83.3%)vs12/66(18.2%);P≤0.01],而PPD结素皮试于抗结核治疗前期及后期的阳性率分别为[50/66(75.8%)vs38/66(57.6%);P>0.05]。结论:结核分枝杆菌抗原特异性γ-IFN体外释放测定评估抗结核治疗疗效较PPD结素皮试临床应用价值更大。     

Small proteins fold through transition states with native-like topologies

The folding pathway of common-type acyl phosphatase (ctAcP) is characterized using psi-analysis, which identifies specific chain-chain contacts using bi-histidine (biHis) metal-ion binding sites. In the transition state ensemble (TSE), the majority of the protein is structured with a near-native topology, only lacking one beta-strand and an alpha-helix. psi-Values are zero or unity for all sites except one at the amino terminus of helix H2. This fractional psi-value remains unchanged when three metal ions of differing coordination geometries are used, indicating this end of the helix experiences microscopic heterogeneity through fraying in the TSE. Ubiquitin, the other globular protein characterized using psi-analysis, also exhibits a single consensus TSE structure. Hence, the TSE of both proteins have converged to a single configuration, albeit one that contains some fraying at the periphery. Models of the TSE of both proteins are created using all-atom Langevin dynamics simulations using distance constraints derived from the experimental psi-values. For both proteins, the relative contact order of the TS models is approximately 80% of the native value. This shared value viewed in the context of the known correlation between contact order and folding rates, suggests that other proteins will have a similarly high fraction of the native contact order. This constraint greatly limits the range of possible configurations at the rate-limiting step.     

Kinetic coupling of folding and prolyl isomerization of beta2-microglobulin studied by mutational analysis

β₂-Microglobulin (β2-m), a protein responsible for dialysis-related amyloidosis, adopts a typical immunoglobulin domain fold with the N-terminal peptide bond of Pro32 in a cis isomer. The refolding of β2-m is limited by the slow trans-to-cis isomerization of Pro32, implying that intermediates with a non-native trans-Pro32 isomer are precursors for the formation of amyloid fibrils. To obtain further insight into the Pro-limited folding of β2-m, we studied the Gdn-HCl-dependent unfolding/refolding kinetics using two mutants (W39 and P32V β2-ms) as well as the wild-type β2-m. W39 β2-m is a triple mutant in which both of the authentic Trp residues (Trp60 and Trp95) are replaced by Phe and a buried Trp common to other immunoglobulin domains is introduced at the position of Leu39 (i.e., L39W/W60F/W95F). W39 β2-m exhibits a dramatic quenching of fluorescence upon folding, enabling a detailed analysis of Pro-limited unfolding/refolding. On the other hand, P32V β2-m is a mutant in which Pro32 is replaced by Val, useful for probing the kinetic role of the trans-to-cis isomerization of Pro32. A comparative analysis of the unfolding/refolding kinetics of these mutants including three types of double-jump experiments revealed the prolyl isomerization to be coupled with the conformational transitions, leading to apparently unusual kinetics, particularly for the unfolding. We suggest that careful consideration of the kinetic coupling of unfolding/refolding and prolyl isomerization, which has tended to be neglected in recent studies, is essential for clarifying the mechanism of protein folding and, moreover, its biological significance.     

Association between competition and obligate mutualism in a chemostat

In this paper, we consider a simple chemostat model involving two obligate mutualistic species feeding on a limiting substrate. Systems of differential equations are proposed as models of this association. A detailed qualitative analysis is carried out. We show the existence of a domain of coexistence, which is a set of initial conditions in which both species survive. We demonstrate, under certain supplementary assumptions, the uniqueness of the stable equilibrium point which corresponds to the coexistence of the two species.