The effect of adrenergic receptor—adenyl cyclase system on myocardial ischemic preconditioning in rats

In order to study the effects of every part of adrenergic reccptor-adenyl cyclase system on ischemic preconditioning of myocardium in rats in vivo, SD rats were divided into three groups: IP group, I/R group and CON group. Rats were received surgical procedure and undergone left coronary artery occlusion and reperfu-sion. Hearts were extracted to analyze the infarct size by TTC staining, to measure serum myocardial enzymes, to study β-AR Bmax and Kd by radioligand binding assay of receptors (RAB), and to check the activity of AC and the content of cAMP by ra-dioimmunoassay (RIA). The infarct area was found much smaller in IP group than I/R group (p <0.001); CK,CK-MB and LDH were found significantly higher in I/R group (p <0.001). The Bmax of β-AR in IP group were higher than in I/R group (p <0.001). No difference of Kd could be seen between IP and I/R group. In IP group, the activity of AC and the content of cAMP were higher than I/R group (p <0.05 and 0.001, respectively). It is concluded that ischemi     

~(60)Coγ射线体外照射对大鼠脾淋巴细胞在体内原发移行和归巢的影响

本文介绍用~(51)Cr 标记淋巴细胞方法,观察了不同剂量~(60)Coγ射线体外照射对大鼠脾淋巴细胞在体内原发移行和归巢的影响。观察结果表明,在注射淋巴细胞悬液后2小时,受照淋巴细胞异常地滞留在肝脏和肺,而归巢到肠系膜淋巴结和肠相关淋巴组织的数量显著减少;辐射对淋巴细胞在体内移行和归巢的影响,除直接与细胞质膜系统损伤有关外,还可能与微丝/微管系统的损伤有关。     

大鼠呼吸道上皮细胞~3H-TdR标记指数

本文利用~3H-TdR 掺入技术研究大鼠呼吸道上皮细胞的标记类型和数量。大鼠腹腔注射7.4×10~4Bq/g(体重)~3H-TdR6小时后,制片计数气管和支气管上皮标记及非标记的基底细胞和粘液细胞,计算出标记指数。结果表明,气管及支气管基底细胞标记指数分别为0.0052和0.0198,粘液细胞标记指数分别为0.0014和0.0047,说明两类细胞都是具有分裂能力的癌形成相关细胞。     

Volumetric assessment of myocardial viability in rats using 3D double contrast enhanced T1 and T2-weighted MRI

Objective: Volumetric evaluation of the myocardial viability post-infarction in rats using 3D in vivo MR imaging at 7 T using injection of an extracellular paramagnetic contrast agent and intravascular superparamagnetic iron oxide nanoparticles in the same imaging session. Materials and methods: Five hours after induction of permanent myocardial infarction in rats (n=6), 3D in vivo T1- and T2-weighted MR Imaging was performed prior to and after Gd-DOTA injection (0.2 mmol/kg) and prior to and after nanoparticle injection (5 mg Fe/kg) to assess infarct size and myocardial viability. Results: 3D MR Imaging using a successive contrast agent injection showed a difference of infarct size after Gd-DOTA injection on T1-weighted images compared to the one measured on T2-weighted images after Gd-DOTA and nanoparticle injection. Conclusion: The use of 3D T1- and T2-weighted MR Imaging using a double contrast agents protocol made possible the accurate characterization of myocardial infarction volume and allowed the detection of myocardial viability post-infarction in rats     

Integrated RF probe for in vivo multinuclear spectroscopy and functional imaging of rat brain using an 11.7 Tesla 89 mm bore vertical microimager

To acquire high quality in vivo NMR data from rat brain using a vertical 89-mm bore magnet, specially designed NMR probes with integrated RF coils and animal handling capability are required. An RF probe design that is also capable of rat head fixation, body support and suitable for physiology monitoring and maintenance was constructed for an 89 mm bore, 11.7 T, vertical microimager which is equipped with a 57-mm i.d. gradient insert. Design concept and practical aspects of probe construction are described in detail. The device allows accurate and highly reproducible positioning of rat head inside the magnet while providing excellent RF performance. Typical results from fMRI, localized in vivo proton and multinuclear spectroscopy using this probe system are presented.     

幼年大鼠甲状腺γ线损伤效应的剂量效应关系

１５日龄大鼠甲腺γ线局部单次外照射后６周，观察和测量滤泡和滤泡上皮细胞形态结构的变化，综合分析甲状腺辐射损伤效应。结果表明，幼年大鼠甲状腺具有较高的辐射敏感性，０．５Ｇｙ照后即可出现显著性变化。通过实验得出了一些形态计量学指标变化与照射剂量之间的定量关系。     

百合水提物对对氯苯丙氨酸失眠模型大鼠睡眠改善作用研究

目的 研究不同剂量的百合水提取物对对氯苯丙氨酸(PCPA)失眠模型大鼠睡眠作用的影响。方法 大鼠腹腔注射PCPA混悬液制备大鼠失眠模型。将造模成功大鼠随机分为模型对照组、百合水提物组-低、百合水提物组-中、百合水提物组-高,另设空白对照组。百合水提物组-低 (100 mg/kg.d)、百合水提物组-中(200 mg/kg.d)、百合水提物组-高(300 mg/kg.d)大鼠连续 7 d 给予相应浓度药液,模型对照组和空白对照组连续 7 d 给予生理盐水灌胃。给药期间,观察大鼠一般状态;给药结束后,观察大鼠体质量变化、睡眠潜伏期、总睡眠时间,同时评价不同脑组织中五羟色胺、5-羟基吲哚乙酸、多巴胺含量的变化。结果 百合水提物各剂量组的大鼠在给药期间的一般状态均优于模型组,体质量增加情况也与正常对照组无显著差异;百合水提物中、高剂量组的睡眠潜伏期与模型组相比显著缩短(P＜0.05),百合水提物各剂量组的睡眠时间与模型组相比显著延长(P＜0.05);与模型对照组比较,各给药组大鼠不同脑组织中的5-HT含量显著升高(P < 0.05,P < 0.01),百合水提物中、高剂量组大鼠不同脑组织中的5-HIAA 含量显著升高(P < 0.05,P < 0.01),同时上述２个给药组大鼠的下丘脑、中缝核中的DA含量显著降低(P < 0.05),海马中仅百合水提物高剂量组的DA含量与对照组相比显著降低(P < 0.05)。结论 百合水提物具有改善PCPA失眠模型大鼠睡眠情况的作用。     

Multi-Slice DCE-MRI Data Using P760 Distinguishes Between Metastatic and Non-Metastatic Rodent Prostate Tumors

An intermediate molecular weight contrast agent P760 was used to investigate the ability of multi-slice dynamic contrast-enhanced MRI (DCE-MRI) to distinguish metastatic from non-metastatic rodent prostate tumors. Non-metastatic AT2.1 and metastatic AT3.1 prostate tumors originally derived from the Dunning prostate cancer model were implanted on the hind leg of Copenhagen rats. Multi-sliced DCE-MRI data were acquired on a SIGNA 1.5 T scanner and analyzed using a recently developed empirical mathematical model. The P760 multi-slice DCE-MRI data in combination with the empirical mathematical model successfully distinguished between metastatic and non-metastatic rodent prostate tumors. Specifically, fitting the data with the empirical model showed that metastatic tumors had significantly faster contrast media uptake (p<0.001) and slower washout rates (p<0.01) than non-metastatic tumors     

Exposure to Urine of Canids and Felids, but not of Herbivores, Induces Defensive Behavior in Laboratory Rats

Predator odors induce defensive behavior in many prey species. For various reasons, studies carried out up to now have been unable to establish whether predator odor recognition is innate or not. Mostly, only particular odors or wild-living (i.e., experienced) test animals have been used in these studies, restricting the conclusiveness of the observations. In the present study, the behavioral effects of exposure to different predator odors on predator odor-naive laboratory male rats were compared with the effects of different nonpredator odors and of a no-odor control stimulus. Results show that exposure to urine of canids and felids, but not of herbivores or conspecifics, induce defensive behaviors. Taken together, the study provides support for the hypothesis that there is an innate recognition of predator odors in laboratory rats.     

Alkoxyresorufin O-dealkylase assay using a rat hepatocyte spheroid microarray

Hepatocyte multicellular aggregates (spheroids), which maintain high expression of liver functions, have been advocated as a useful culture technique for various cell-based assays. In this study, we investigated the drug metabolic function of a hepatocyte spheroid microarray (HSM) chip, which contained an array of 672 spheroids of primary rat hepatocytes within a 100-mm² region in the center of a poly(methylmethacrylate) plate (24 × 24 mm) and used an alkoxyresorufin (ethoxy-, methoxy-, pentoxy- and benzyloxyresorufin) O-dealkylase assay system. Ethoxyresorufin O-dealkylase (EROD) activity of the HSM chip initiated by 3-methylcholanthrene (3-MC), an inducer of cytochrome P450 enzymes, was 5- to 10-fold higher than that of monolayer hepatocytes, with activity being maintained for at least 2 weeks. We also demonstrated that 3-MC induced EROD, methoxyresorufin O-dealkylase (MROD) and benzyloxyresorufin O-dealkylase (BROD) activities in the HSM chip, while sodium phenobarbital (P450 inducer) induced pentoxyresorufin O-dealkylase (PROD), BROD, EROD and MROD activities. Induction of these activities was confirmed by increased gene expression of the related P450 enzymes. These results showed that the HSM chip had a good response to P450 inducers and that function was maintained for long periods of time. The HSM chip therefore may be a promising cellular platform for drug metabolic assays using hepatocytes.