脂多糖通过补体途径诱导小鼠产生白三烯B4

目的:研究脂多糖(LPS)对人血清中补体系统的激活及在小鼠模型中诱导产生白三烯B4(LTB4)。方法:LPS包被ELISA板,利用血清中补体C4、C3沉积实验检测补体成分被LPS活化的情况,通过尾静脉注射小鼠LPS后不同时间点ELISA定量检测LTB4,评价补体系统的活化和炎症因子的产生。结果与结论:血清系统ELISA检测发现LPS可以激活补体系统,且以凝集素途径为主;动物实验中LTB4被LPS诱导后1～3 h达到峰值,之后回落。C1INH对血清补体活化和动物模型中LTB4的产生均有显著抑制。     

IL-4 induces differentiation and expansion of Th2 cytokine-producing eosinophils

Innate effector cells that produce Th2-type cytokines are critical in Th2 cell-mediated immune responses. However, it is not known how these cells acquire the ability to produce Th2 cytokines. IL-4 is a potent inducer that directs differentiation of naive CD4(+) T cells into CD4(+) Th2 effector cells. To determine whether IL-4 can induce differentiation and expansion of Th2 cytokine-producing innate cells, we used mice whose il-4 gene was replaced by a knock-in green fluorescence protein (gfp) gene. We found that, directly ex vivo, IL-4 increased the number of GFP(+) cells in the airway and the lung tissue in an Ag-specific manner. The majority of GFP(+) cells were eosinophils, suggesting that IL-4 plays a pivotal role in expanding IL-4-producing eosinophils in vivo. IL-4-producing eosinophils showed some unique features compared with IL-4-producing CD4(+) T cells. They exhibited biallelic expression of the il-4 gene when stimulated and were more dominant IL-4- and IL-5-producing cells. Furthermore, we show that IL-4 drove bone marrow progenitor cells to differentiate into Th2 cytokine-producing eosinophils in vitro. These results strongly suggest IL-4 is a potent factor in directing bone marrow progenitor cells to differentiate into Th2 cytokine-producing eosinophils.     

A novel conotoxin from Conus delessertii with posttranslationally modified lysine residues

A major peptide, de13a from the crude venom of Conus delessertii collected in the Yucatan Channel, Mexico, was purified. The peptide had a high content of posttranslationally modified amino acids, including 6-bromotryptophan and a nonstandard amino acid that proved to be 5-hydroxylysine. This is the first report of 5-hydroxylysine residues in conotoxins. The sequence analysis, together with cDNA cloning and a mass determination (monoisotopic mass of 3486.76 Da), established that the mature toxin has the sequence DCOTSCOTTCANGWECCKGYOCVNKACSGCTH, where O is 4-hydroxyproline, W 6-bromotryptophan, and K 5-hydroxylysine, the asterisk represents the amidated C-terminus, and the calculated monoisotopic mass is 3487.09 Da. The eight Cys residues are arranged in a pattern (C-C-C-CC-C-C-C) not described previously in conotoxins. This arrangement, for which we propose the designation of framework #13 or XIII, differs from the ones (C-C-CC-CC-C-C and C-C-C-C-CC-C-C) present in other conotoxins which also contain eight Cys residues. This peptide thus defines a novel class of conotoxins, with a new posttranslational modification not previously found in other Conus peptide families.     

Interaction between quinolones antibiotics and bacterial outer membrane porin OmpF

In these work, we try to establish a relation between the hydrophobicity of some quinolones and their interaction with OmpF. In order to do that, the values of the binding constant of some quinolones of different "generations" with OmpF were determined by UV-visible spectrophotometry and by fluorimetry. Our results show that there is a strong interaction between all the drugs and the protein and that it becomes larger for the last "generation" fluoroquinolones. These results were compared with previous ones obtained for the interaction of these drugs with simpler biomembrane models (liposomes) and it is possible to conclude that some of the quinolones associate preferably with the protein than with these models. This suggests that an interaction drug/porin is, probably, the preferentially used for the latest fluoroquinolones what makes reasonable to believe that a strong affinity for OmpF means a better capacity to transpose the barrier formed by the outer membrane.     

Some physical properties of teosinte (Zea mays subsp. parviglumis) pollen

In parts of the world where teosinte and maize are grown in close proximity, there is concern about gene flow between them. Pollen is the primary vehicle for gene flow. Quantifying the biophysical properties of pollen, such as its settling speed and dehydration rate, is important for evaluating outcrossing potential. These properties were measured for teosinte (Zea mays subsp. parviglumis) pollen. Pollen was found to have an average settling speed of 0.165 m s(-1), which agrees well with theoretical values based on the size of the pollen grains. The conductance of the pollen wall for water was derived from the time rate of change of pollen grain size and gave an average conductance of 3.42x10(-4) m s(-1). Water potential, psi, of teosinte pollen was determined at various values of relative water content (dry-weight basis), theta, by using a thermocouple psychrometer and by allowing samples of pollen to come to vapour equilibrium with various saturated salt solutions. Non-linear regression analysis of the data yielded psi (MPa) = -4.13 theta(-1.23) (r2=0.77). Results for conductance and psi were incorporated into a model equation for the rate of water loss from pollen grains, which yielded results that agreed well (r2=0.96) with observations of water loss from pollen grains in air. The data reported here are important building blocks in a model of teosinte pollen movement and should be helpful in establishing the main factors influencing the degree and the direction of pollination between teosinte populations and between maize and teosinte.     

Ecuadorian Banana Farms Should Consider Organic Banana with Low Price Risks in Their Land-Use Portfolios

Organic farming is a more environmentally friendly form of land use than conventional agriculture. However, recent studies point out production tradeoffs that often prevent the adoption of such practices by farmers. Our study shows with the example of organic banana production in Ecuador that economic tradeoffs depend much on the approach of the analysis. We test, if organic banana should be included in economic land-use portfolios, which indicate how much of the land is provided for which type of land-use. We use time series data for productivity and prices over 30 years to compute the economic return (as annualized net present value) and its volatility (with standard deviation as risk measure) for eight crops to derive land-use portfolios for different levels of risk, which maximize economic return. We find that organic banana is included in land-use portfolios for almost every level of accepted risk with proportions from 1% to maximally 32%, even if the same high uncertainty as for conventional banana is simulated for organic banana. A more realistic, lower simulated price risk increased the proportion of organic banana substantially to up to 57% and increased annual economic returns by up to US$ 187 per ha. Under an assumed integration of both markets, for organic and conventional banana, simulated by an increased coefficient of correlation of economic return from organic and conventional banana (ρ up to +0.7), organic banana holds significant portions in the land-use portfolios tested only, if a low price risk of organic banana is considered. We conclude that uncertainty is a key issue for the adoption of organic banana. As historic data support a low price risk for organic banana compared to conventional banana, Ecuadorian farmers should consider organic banana as an advantageous land-use option in their land-use portfolios.     

Perioperative Care and the Importance of Continuous Quality Improvement—A Controlled Intervention Study in Three Tanzanian Hospitals

IntroductionSurgical services are increasingly seen to reduce death and disability in Sub-Saharan Africa, where hospital-based mortality remains alarmingly high. This study explores two implementation approaches to improve the quality of perioperative care in a Tanzanian hospital. Effects were compared to a control group of two other hospitals in the region without intervention.MethodsAll hospitals conducted quality assessments with a Hospital Performance Assessment Tool. Changes in immediate outcome indicators after one and two years were compared to final outcome indicators such as Anaesthetic Complication Rate and Surgical Case Fatality Rate.ResultsImmediate outcome indicators for Preoperative Care in the intervention hospital improved (52.5% in 2009; 84.2% in 2011, p<0.001). Postoperative Inpatient Care initially improved to then decline again (63.3% in 2009; 70% in 2010; 58.6% in 2011). In the control group, preoperative care declined from 50.8% (2009) to 32.8% (2011, p <0.001), while postoperative care did not significantly change. Anaesthetic Complication Rate in the intervention hospital declined (1.89% before intervention; 0.96% after intervention, p = 0.006). Surgical Case Fatality Rate in the intervention hospital declined from 5.67% before intervention to 2.93% after intervention (p<0.0010). Surgical Case Fatality Rate in the control group was 4% before intervention and 3.8% after intervention (p = 0.411). Anaesthetic Complication Rate in the control group was not available.DiscussionImmediate outcome indicators initially improved, while at the same time final outcome declined (Surgical Case Fatality, Anaesthetic Complication Rate). Compared to the control group, final outcome improved more in the intervention hospital, although the effect was not significant over the whole study period. Documentation of final outcome indicators seemed inconsistent. Immediate outcome indicators seem more helpful to steer the Continuous Quality Improvement program.ConclusionSpecific interventions as part of Continuous Quality Improvement might lead to sustainable improvement of the quality of care, if embedded in a multi-faceted approach.     

氨氯地平联合依那普利治疗原发性高血压的临床疗效及对患者左心室肥厚的影响

摘要目的：探讨氨氯地平联合依那普利治疗原发性高血压的临床效果,观察联合用药对左心室肥厚的影响。方法：选择本院收治的原发性高血压患者92例,随机分为观察组和对照组,各46例,对照组给予苯磺酸左旋氨氯地平5mg,1次／d,口服;观察组在对照组基础上加用马来酸依那普利10mg,2次／d,口服,疗程均为24周。观察两组治疗前后血压变化,应用超声心动图测量两组左心室厚度变化。结果：治疗后,观察组总有效率为91_3％;对照组总有效率为73．9％,观察组总有效率高于对照组（P〈0．05）。治疗前两组心率、血压比较无统计学差异（P〉0．05）,治疗后两组血压均明显降低,观察组收缩压、舒张压明显低于对照组（P〈O．05）;观察组心率明显低于对照组（P〈0．01）。治疗前两组左心室舒张末期室间隔厚度（Leaventricularend—diastolicventricularseptalthickness,IVST）、左心室后壁厚度（1eftventricularposteriorwallthickness,U,PwT）和左室射血分数（Leftventricularejectionfxaction,LVEF）比较无统计学差异（P〉0．05）;治疗后观察组IVST、L、,PwT明显低于对照组,LVEF明显高于对照组（P〈0．05）。结论：氨氯地平联合依那普利治疗原发性高血压能有效扭转左心室肥厚,降压效果较单独应用氨氯地平更佳。