IGF1在脑缺血大鼠脑组织中的表达与通络救脑注射液的脑保护作用

目的:观察脑缺血模型大鼠血清及脑组织中IGF1蛋白表达水平,以及通络救脑注射液对该因子表达水平的影响,分析通络救脑注射液的脑保护作用途径。方法:以线栓法制作大鼠大脑中动脉缺血模型(MCAO),将SD大鼠随机分为空白对照组、模型组及通络救脑注射药组,分别在造模后12小时、24小时、3天、7天4个时间点采取动物血清和脑组织,以免疫组化、酶联免疫(ELISA)以及RTPCR的方法,分别检测IGF1的表达部位及定量检测该因子的蛋白及mRNA表达水平,并测定血清NSE含量。结果:IGF1在正常脑组织有表达,在脑缺血后24小时表达增多,此后随脑缺血时间的延长不断减少;通络救脑组IGF1各时间点表达均高于模型组。模型组血清NSE水平显著升高,各时间点与正常组均有显著差异,通络救脑注射液组血清NSE水平在12小时、1天和7天时显著低于模型组。结论:大鼠脑缺血损伤后IGF1表达减少与神经元的坏死有相关性,通络救脑注射液能够提高其表达水平,对缺血损伤的脑组织发挥保护作用。     

Traditional Versus Multivariate Methods for Identifying Jaguar,Puma, and Large Canid Tracks

ABSTRACT The jaguar (Panthera onca) and puma (Puma concolor) are the largest felids of the American Continent and live in sympatry along most of their distribution. Their tracks are frequently used for research and management purposes, but tracks are difficult to distinguish from each other and can be confused with those of big canids. We used tracks from pumas, jaguars, large dogs, and maned wolves (Chrysocyon brachyurus) to evaluate traditional qualitative and quantitative identification methods and to elaborate multivariate methods to differentiate big canids versus big felids and puma versus jaguar tracks (n = 167 tracks from 18 zoos). We tested accuracy of qualitative classification through an identification exercise with field-experienced volunteers. Qualitative methods were useful but there was high variability in accuracy of track identification. Most of the traditional quantitative methods showed an elevated percentage of misclassified tracks (≥20%). We used stepwise discriminant function analysis to develop 3 discriminant models: 1 for big canid versus big felid track identification and 2 alternative models for jaguar versus puma track differentiation using 1) best discriminant variables, and 2) size-independent variables. These models had high classification performance, with <10% of error in the validation procedures. We used simpler discriminant models in the elaboration of identification keys to facilitate track classification process. We developed an accurate method for track identification, capable of distinguishing between big felids (puma and jaguar) and large canids (dog and maned wolf) tracks and between jaguar and puma tracks. Application of our method will allow a more reliable use of tracks in puma and jaguar research and it will help managers using tracks as indicators of these felids' presence for conservation or management purposes.     

DNA sequence-specific ligands: XIII. New Dimeric Hoechst 33258 molecules, inhibitors of HIV-1 integrase in vitro

Dimeric Hoechst 33258 molecules [dimeric bisbenzimidazoles (DBBIs)] that, upon binding, occupy one turn of the B form of DNA in the narrow groove were constructed by computer simulation. Three fluorescent DBBIs were synthesized; they consist of two bisbenzimidazole units tail-to-tail linked to phenolic hydroxy groups via penta- or heptamethylene or tri(ethylene glycol) spacers and have terminal positively charged N.N-dimethylaminopropyl carboxamide groups in the molecule. The absorption spectra of the DBBIs in the presence of different DNA concentrations showed a hypochromic effect and a small shift of the absorption band to longer wavelengths, which indicated the formation of a complex with DNA. The presence of an isobestic point in the spectrum indicates the formation of one type of DBBI-DNA complexes. The interaction of DBBIs with DNA was studied by CD using a cholesteric liquid-crystalline dispersion (CLD) of DNA. The appearance of a positive band in the absorption region of ligand chromophores in the CD spectrum of the DNA CLD indicates the formation of a DBBI-DNA complex in which ligand chromophores are arranged at an angle close to 54 degrees relative to the helix axis of DNA, which suggests the localization of the DBBI in the narrow groove of DNA. All the DBBIs were found to be in vitro inhibitors of HIV-1 DNA integrase in the 3'-processing reaction, and, of the three DBBIs, two dimers inhibit HIV-1 integrase even in submicromolar concentrations.     

Fire,landscape change and models of small mammal habitat suitability at multiple spatial scales

Fire is an important process in many ecosystems, but inappropriate fire regimes can adversely affect biodiversity. We identified a naturally flammable heathy woodland ecosystem where the use of planned fire had increased the extent of older vegetation, and quantified the abundance of two small native mammals in this landscape (silky mouse Pseudomys apodemoides and heath rat P. shortridgei). We defined four time‐since‐fire (TSF) categories representing a 2‐ to 55‐year post‐fire sequence and, on the basis of a habitat accommodation model, predicted that both species would select younger age‐classes over older ones. We also predicted that (i) much of the variance in vegetation structure would remain unexplained by TSF and (ii) statistical models of mammal abundance and occupancy including structural variables as predictors would be better than models including TSF. Pseudomys apodemoides selected 17‐ to 23‐year‐old sites, while there was no evidence that P. shortridgei selected a particular TSF category, findings that were inconsistent with our predictions. In line with our predictions, relatively large portions of the variance in vegetation structure remained unexplained by TSF (adjustedr² for four structural variables: 0.24, 0.29, 0.35 and 0.57), and in three of four cases there was strong evidence that statistical models of mammal abundance and occupancy including structural variables were better than those including TSF. At the site scale (hectares), P. shortridgei abundance was positively related to the cover of dead material at the base of Xanthorrhoea plants and at the trap scale (metres), the trapability of both species was significantly related to vegetation volume at 0–20 cm. Our findings suggest that TSF may not be a good proxy for either vegetation structure or species abundance/occupancy.