双源CT冠状动脉血管成像诊断心肌桥的价值探讨

目的：研究双源CT冠状动脉血管成像诊断心肌桥的临床价值。方法：选择260例具有典型心前区不适的患者进行双源CT冠脉血管成像检查,观察其发生部位,测量其长度和深度并进行分析。结果：260例受检患者中,62例共70段存在心肌桥,检出率达20.76%,高于文献报道的检出率18.2%。所有心肌桥均发生于左前降支,其中近段17段（24.4%）,中段43段（61.4%）,远段10段（14.2%）。心肌桥平均长度为15.8±6.4mm,深度为1.4±0.85mm。结论：双源CT冠状动脉血管成像因其便捷无创,不受心率严格限制且价格低廉可作为心肌桥筛查的理想检查手段。     

血液磁极化疗法对糖尿病兔胰岛功能的影响

目的观察血液磁极化疗法(简称血磁治疗)对糖尿病(DM)的治疗效果和对胰岛功能的影响。方法制备了四氧嘧啶DM兔模型20只,随机分为两组,即DM模型血磁治疗组及DM模型未治疗组,同时设立正常对照组10只,分别测定治疗前后空腹血糖(FPG)、糖化血红蛋白(HbA1c)、胰岛素(INS)及C-肽(C-P),并于观察期结束后处死动物取胰腺组织常规石蜡包埋切片,行HE及Mallory三色法特殊染色观察3组胰岛形态学变化。结果血磁治疗显著降低DM兔的FPG(P<0.001)。DM治疗组INS及C-P水平较治疗前明显升高(P<0.01),与未治疗组相比差异显著(P<0.05)。胰岛病理改变可见治疗组β细胞数量明显多于DM未治疗组,提示血磁疗法具有促进胰岛修复,改善胰岛功能的作用。结论血磁疗法能够促进DM时受损胰岛组织的修复,改善胰岛β细胞分泌功能,降血糖作用明显。     

The Arabidopsis MATE transporter TT12 acts as a vacuolar flavonoid/H+ -antiporter active in proanthocyanidin-accumulating cells of the seed coat

Phenotypic characterization of the Arabidopsis thaliana transparent testa12 (tt12) mutant encoding a membrane protein of the multidrug and toxic efflux transporter family, suggested that TT12 is involved in the vacuolar accumulation of proanthocyanidin precursors in the seed. Metabolite analysis in tt12 seeds reveals an absence of flavan-3-ols and proanthocyanidins together with a reduction of the major flavonol quercetin-3-O-rhamnoside. The TT12 promoter is active in cells synthesizing proanthocyanidins. Using translational fusions between TT12 and green fluorescent protein, it is demonstrated that this transporter localizes to the tonoplast. Yeast vesicles expressing TT12 can transport the anthocyanin cyanidin-3-O-glucoside in the presence of MgATP but not the aglycones cyanidin and epicatechin. Inhibitor studies demonstrate that TT12 acts in vitro as a cyanidin-3-O-glucoside/H(+)-antiporter. TT12 does not transport glycosylated flavonols and procyanidin dimers, and a direct transport activity for catechin-3-O-glucoside, a glucosylated flavan-3-ol, was not detectable. However, catechin-3-O-glucoside inhibited TT12-mediated transport of cyanidin-3-O-glucoside in a dose-dependent manner, while flavan-3-ol aglycones and glycosylated flavonols had no effect on anthocyanin transport. It is proposed that TT12 transports glycosylated flavan-3-ols in vivo. Mutant banyuls (ban) seeds accumulate anthocyanins instead of proanthocyanidins, yet the ban tt12 double mutant exhibits reduced anthocyanin accumulation, which supports the transport data suggesting that TT12 mediates anthocyanin transport in vitro.     

Application of Perturbation Simulations in Population Risk Assessment for Different Life History Strategies and Elasticity Patterns

Population structure and life history strategies are determinants of how populations respond to stressor-induced impairments in organism-level responses. Effects on population growth rate were modeled using seven theoretical constructs that represented the life history strategies and elasticity patterns of a broad range of species. Simulations of low to high ranges of simultaneous reductions in survival and reproduction were conducted and results indicated that stressor impacts on population growth rate were a function of population characteristics and the magnitude of the stress. Species that had high reproductive elasticity had greater population-level impacts than species with high survival elasticity for the same organism-level effects. Perturbation simulations were performed to assess the extinction risk in two species with similar elasticity patterns but different life history strategies: mysid shrimp, Americamysis bahia, and the gypsy moth, Lymantria dispar, which can be related to classical K- and r-strategists, respectively. Deterministic extinction risk was greater for the K-strategist, which indicated that population level risks were dependent on life history strategies, and toxicity values (e.g., LC50s) should be interpreted with caution. Ecological risk assessments should consider both population structure and life history strategy of an ecological receptor, in addition to the intrinsic sensitivity of the species to contaminant stressors.     

Cardiac synthesis, processing, and coronary release of enkephalin-related peptides

Although preproenkephalin mRNA is abundant in the heart, the myocardial synthesis and processing of proenkephalin is largely undefined. Isolated working rat hearts were perfused to determine the rate of myocardial proenkephalin synthesis, its processing into enkephalin-containing peptides, their subsequent release into the coronary arteries, and the influence of prior sympathectomy. Enkephalin-containing peptides were separated by gel filtration and quantified with antisera for specific COOH-terminal sequences. Proenkephalin, peptide B, and [Met(5)]enkephalin-Arg(6)-Phe(7) (MEAP) comprised 95% of the extracted myocardial enkephalins (35 pmol/g). Newly synthesized enkephalins, estimated during a 1-h perfusion with [(14)C]phenylalanine (4 pmol x h(-1) x g wet wt(-1)), were rapidly cleared from the heart during a second isotope-free hour. Despite a steady release of enkephalins into the coronary effluent (4 pmol x h(-1) x g wet wt(-1)), enkephalin replacement apparently exceeded its release, and tissue enkephalins actually accumulated during hour 2. In contrast to the tissue, methionine-enkephalin accounted for more than half of the released enkephalin. Chemical sympathectomy produced an increase in total enkephalin content similar to that observed after 2-h control perfusion. This observation suggested that the normal turnover of myocardial enkephalin may depend in part on continued sympathetic influences.     

Two-dimensional nuclear magnetic resonance study of brain natriuretic peptide in aqueous solution.

Two dimensional NMR spectra of porcine brain natriuretic peptide have been recorded at 400 MHz. Peak assignments have been made and the combined information from chemical shifts, coupling constants, temperature coefficients, exchange studies and nuclear Overhauser effects has been used to determine the conformation of pBNP in aqueous media. Overall the peptide appears to be conformationally averaged with the possibility of some restricted flexibility in localized regions. The conformation of porcine brain natriuretic peptide in water is compared to previous studies in d6-DMSO and to studies of atrial natriuretic peptide and some closely related analogues in H2O and d6-DMSO.     

Impact of Legume Flour Addition on Pasta Structure: Consequences on Its <Emphasis Type="Italic">In Vitro</Emphasis> Starch Digestibility

Pasta is popular for its ease of cooking and its low glycaemic index (GI). This interesting nutritional property can be attributed to its specific compact structure generally described as a protein network entrapping starch granules. Despite this low GI, pasta is poor in fibres and lack some essential amino acids. To enhance its nutritional composition, pasta can be fortified with non-traditional ingredients such as legume flours. The objective of this study was to investigate the impact of legume flour addition on pasta structure and the inherent consequences on the in vitro digestibility of starch. The addition of a high level (35%, w/w) of legume flour, especially split pea flour, induced some minor structural changes in pasta. The inclusion of fibres, the dilution of gluten proteins by albumins and globulins, and the larger amount of thin protein films (in split pea pasta) may have favoured higher susceptibility of starch to digestive enzymes. At the opposite, the presence of some partially gelatinised starch granules in the core of fortified pasta may have favoured the decrease in the in vitro starch digestibility. As a consequence, a high level of legume flour addition in pasta did not have any significant impact on its in vitro starch digestibility. A high level of split pea and faba bean flours can thus be added to pasta to increase its nutritional composition while keeping its low glycaemic index.     

黑皮质素受体-4调节通路的研究进展

黑皮质素系统来自阿片-促黑素细胞皮质素原,在中枢摄食行为和能量平衡代谢中起到重要作用,此系统生理功能的发挥主要通过与下丘脑神经元细胞上特定膜受体（黑皮质素受体）结合完成。黑皮质素受体（MCR）有五种亚型（MC1R-MC5R）,其中参与体重调节的受体主要是黑皮质素受体3（MC3R）和黑皮质素受体4（MC4R）。MC4R属于G蛋白耦联受体,具有七次跨膜结构。作为一种膜受体,MC4R发挥体重调节作用,一方面受外界激动剂或拮抗剂的调节;另一方面,此受体活化后会影响到细胞内的信号调节通路。研究MC4R的功能首先要了解受体的结构,本文对G蛋白耦联受体的结构进行了较详细的叙述,MC4R经信号调节通路,激活腺苷酸环化酶,增加cAMP的浓度,最终通过影响细胞内基因的转录和翻译,来调节体重和能量的消耗。