Thioredoxin-interacting protein deficiency disrupts the fasting-feeding metabolic transition

Through a positional cloning approach, the thioredoxin-interacting protein gene (Txnip) was recently identified as causal for a form of combined hyperlipidemia in mice (Bodnar, J. S., A. Chatterjee, L. W. Castellani, D. A. Ross, J. Ohmen, J. Cavalcoli, C. Wu, K. M. Dains, J. Catanese, M. Chu, S. S. Sheth, K. Charugundla, P. Demant, D. B. West, P. de Jong, and A. J. Lusis. 2002. Positional cloning of the combined hyperlipidemia gene Hyplip1. Nat. Genet. 30: 110-116). We now show that Txnip-deficient mice in the fed state exhibit a metabolic profile similar to fasted mice, including increased levels of plasma ketone bodies and free fatty acids, decreased glucose, and increased hepatic expression of peroxisome proliferator-activated receptor-gamma coactivator-1alpha, phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, and acyl-CoA oxidase. Dramatic differences in the expression of key metabolic enzymes were also observed in other tissues, and the fat-to-muscle ratio of Txnip-deficient mice was increased by approximately 40%. We demonstrate an effect of Txnip on the redox status, as the Txnip-deficient mice in the fed state had a significant increase in the ratio of NADH to NAD(+). Surprisingly, we observed that Txnip-deficient mice and wild-type mice had similar levels of thioredoxin activity, suggesting that the effects of Txnip deficiency may be mediated in part by other interactions. These results indicate a role for Txnip in the metabolic response to feeding and the maintenance of the redox status.     

Processing of Auditory Midbrain Interspike Intervals by Model Neurons

A question central to sensory processing is how signal information is encoded and processed by single neurons. Stimulus features can be represented through rate coding (via firing rate), temporal coding (via firing synchronization to temporal periodicities), or temporal encoding (via intricate patterns of spike trains). Of the three, examples of temporal encoding are the least documented. One region in which temporal encoding is currently being explored is the auditory midbrain. Midbrain neurons in the plainfin midshipman generate different interspike interval (ISI) distributions depending on the frequencies of the concurrent vocal signals. However, these distributions differ only along certain lengths of ISIs, so that any neurons trying to distinguish the distributions would have to respond selectively to specific ISI ranges. We used this empirical observation as a realistic challenge with which to explore the plausibility of ISI-tuned neurons that could validate this form of temporal encoding. The resulting modeled cells—point neurons optimized through multidimensional searching—were successfully tuned to discriminate patterns in specific ranges of ISIs. Achieving this task, particularly with simplified neurons, strengthens the credibility of ISI coding in the brain and lends credence to its role in auditory processing.     

尿毒症皮肤瘙痒患者采取腹膜透析与血液透析治疗的效果探究

目的：探究尿毒症皮肤瘙瘁患者采取腹膜透析与血液透析治疗的临床效果,并为该病的临床治疗提供经验积累。方法：选取我院肾内科于2005年1月-2012年12月收治的52例尿毒症皮肤瘙痒患者,利用随机数字表法进行分组,分别设为研究组和对照组。其中对照组实施血液透析治疗,而研究组开展腹膜透析治疗。记录两组在治疗前和治疗后第8周末血生化客观指标及皮肤瘙痒程度,并做好对比。结果：两组在治疗前的皮肤瘙痒评分、β2-MG、PTH、p3,BUN、SCr值差异无统计学意义（P〉0．05）;治疗后,研究组皮肤瘙瘁评分为（3．4±0．8）分,对照组为（5．8±0．9）分,差异有统计学意义（P〈0．05）。治疗后,研究组β2-MG、PTH及Ps．均低于对照组,差异有统计学意义（P〈0．05）。结论：尿毒症皮肤瘙痒患者的主要致敏因子为大中分子,采取腹膜透析能够有效清除大分子物质,进而达到瘙痒程度的有效改善。     

重组人MASP2蛋白在大肠杆菌中的表达和纯化

目的:获得酶原形式的重组人甘露聚糖结合凝集素相关丝氨酸蛋白酶2(MASP2)。方法:在大肠杆菌中诱导表达重组人MASP2全长蛋白,包涵体裂解后,经复性、透析、浓缩、考马斯亮蓝染色、SDS-PAGE及Western印迹,鉴定纯化结果及酶活性。结果:复性后的MASP2蛋白经考马斯亮蓝染色未见杂带。自激活实验表明,当MASP2浓度在1μmool/L以下时,无论在4℃还是37℃,都能较稳定地保持酶原形式;蛋白浓度为3.5μmool/L时只能在4℃保持稳定,37℃发生自激活;蛋白浓度达到12μmool/L后,在4℃时已不能稳定存在。结论:获得了较纯的重组人MASP2蛋白,且具有自激活活性。     

变性高效液相色谱技术对创伤弧菌检测的研究

应用PCR结合变性高效液相色谱技术对创伤弧菌进行检测,建立创伤弧菌快速准确的检测新方法。经过DHPLC分析条件优化,在DHPLC非变性温度下分析创伤弧菌特异性PCR扩增产物。同时进行方法特异性、灵敏度、重复性实验。实验结果表明所建立的创伤弧菌PCR-DHPLC检测方法特异性强、灵敏度高、重现性好、结果稳定可靠、检测时间短,检测低限可达到124 CFU/mL,是创伤弧菌快速检测的新技术。     

胸内正压对正常人左室功能影响及其力学原理

目的：探讨胸内正压对正常人左室射血及充盈的影响及其力学原理。方法：超声心动图观测30例正常人初始时与标准乏氏动作张力期10s时左室舒张末容积（LVEDV）、左室收缩末容积（LVESV）、每搏量（SV）、射血分值（EF）、流入道血流速度（E峰、A峰）、E／A值、二尖瓣环舒张早期运动速度（e）及舒张早期充盈压（E/e）的变化。结果：与初始时比较,标准乏氏动作张力期LVEDV、LVESV及SV减低而心率（陬）增快（P均〈0．001）,EF值增加,但无统计学意义（P〉0．05）;E峰与E／A值减低（P均〈O．05）;e没有变化（P〉0．05）．E／e值减低（P〈O．05）。结论：胸内正压对左室游离壁的力学作用促进了左室收缩运动而阻碍了左室舒张运动,会引起EF值增加,E峰及E／A值减低;2,胸内正压降低了肺静脉系统与心脏的跨壁压力,增加了血流阻力也是导致肺静脉系统与左室血液回流减少．E峰减低．E／e值减低的一个原因。     

Energy Crop and Biotechnology for Biofuel Production

Selection of energy crops is the first priority for large-scale biofuel production in China. As a major topic, it was extensively discussed in the Second International Symposium on Bioen-     

Amino acid residues constituting the agonist binding site of the human P2X3 receptor

Homomeric P2X3 receptors are present in sensory ganglia and participate in pain perception. Amino acid (AA) residues were replaced in the four supposed nucleotide binding segments (NBSs) of the human (h) P2X3 receptor by alanine, and these mutants were expressed in HEK293 cells and Xenopus laevis oocytes. Patch clamp and two-electrode voltage clamp measurements as well as the Ca(2+) imaging technique were used to compare the concentration-response curves of the selective P2X1,3 agonist α,β-methylene ATP obtained at the wild-type P2X3 receptor and its NBS mutants. Within these NBSs, certain Gly (Gly-66), Lys (Lys-63, Lys-176, Lys-284, Lys-299), Asn (Asn-177, Asn-279), Arg (Arg-281, Arg-295), and Thr (Thr-172) residues were of great importance for a full agonist response. However, the replacement of further AAs in the NBSs by Ala also appeared to modify the amplitude of the current and/or [Ca(2+)](i) responses, although sometimes to a minor degree. The agonist potency decrease was additive after the simultaneous replacement of two adjacent AAs by Ala (K65A/G66A, F171A/T172A, N279A/F280A, F280A/R281A) but was not altered after Ala substitution of two non-adjacent AAs within the same NBS (F171A/N177A). SDS-PAGE in the Cy5 cell surface-labeled form demonstrated that the mutants appeared at the cell surface in oocytes. Thus, groups of AAs organized in NBSs rather than individual amino acids appear to be responsible for agonist binding at the hP2X3 receptor. These NBSs are located at the interface of the three subunits forming a functional receptor.     

Chronic stress and its effects on adrenal cortex apoptosis in pregnant rats

The model of chronic intermittent stress by immobilization during pregnancy may produce alterations in the mechanisms that maintain adrenal gland homeostasis. In earlier investigations using this model, significant variations in plasma prolactin and corticosterone levels, and adrenal gland weights were observed. We hypothesized that chronic stress causes changes in apoptosis in the adrenal glands of pregnant rats. We identified and quantified apoptotic cells in the adrenal cortex and examined their ultrastructural characteristics using transmission electron microscopy. Adrenal glands of pregnant rats at gestation days 12, 17 and 21 were studied for control and experimental (stressed) rats. Immunolabelling techniques, stereological analysis and image quantification of adrenal gland sections were combined to determine differences in apoptosis in the different cell populations of the adrenal cortex. The apoptotic index of the experimental rats showed a significant reduction at gestation day 17, while at days 12 and 21 there were no differences from controls. Moreover, the apoptotic index of the reticular zones in control and experimental animals showed a significant increase compared to the glomerular and fascicular zones at the three gestation times studied. Chronic stress by immobilization reduced the caspase-dependent apoptotic index at gestation day 17, which may be related to variations in plasma concentrations of estrogens and prolactin.