Morphine-induced suppression of saccharin intake is correlated with elevated corticosterone levels

Rats suppress intake of a saccharin conditioned stimulus (CS) when paired with a drug of abuse. This phenomenon, however, is not uniform across all subjects and is greater following exposure to stress and in animals that more readily self-administer drugs of abuse. The present study was designed to examine these individual differences in intake suppression following seven saccharin-morphine pairings. Plasma corticosterone also was evaluated both before and after conditioning in order to determine whether the magnitude of CS suppression is, or is not, related to circulating corticosterone levels. The findings indicated that, while all rats were exposed to the same number of saccharin-morphine pairings, only half of these animals actually suppressed intake of the saccharin CS. Moreover, the results showed that greater suppression of CS intake was associated with higher corticosterone levels at test (r=-0.84, P<0.0001). Taken together, the results demonstrate that individual differences affect not only the reduction in CS intake following taste-drug pairings, but also the associated cue-induced elevation in circulating corticosterone.     

GM1 ganglioside treatment protects against long-term neurotoxic effects of neonatal X-irradiation on cerebellar cortex cytoarchitecture and motor function

Exposure of neonatal rats to a 5 Gy dose of X-irradiation induces permanent abnormalities in cerebellar cortex cytoarchitecture (disarrangement of Purkinje cells, reduction of thickness of granular cortex) and neurochemistry (late increase in noradrenaline levels), and motor function (ataxic gait). The neuroprotective effects of gangliosides have been demonstrated using a variety of CNS injuries, including mechanical, electrolytic, neurotoxic, ischemic, and surgical lesions. Here, we evaluated whether systemically administered GM1 ganglioside protects against the long-term CNS abnormalities induced by a single exposure to ionizing radiation in the early post-natal period. Thus, neonatal rats were exposed to 5 Gy X-irradiation, and subcutaneously injected with one dose (30 mg/kg weight) of GM1 on h after exposure followed by three daily doses. Both at post-natal days 30 and 90, gait and cerebellar cytoarchitecture in X-irradiated rats were significantly impaired when compared to age-matched controls. By contrast, both at post-natal days 30 and 90, gait in X-irradiated rats that were treated with GM1 was not significantly different from that in non-irradiated animals. Furthermore, at post-natal day 90, cerebellar cytoarchitecture was still well preserved in GM1-treated, X-irradiated animals. GM1 failed to modify the radiation-induced increase in cerebellar noradrenaline levels. Present data indicate that exogenous GM1, repeatedly administered after neonatal X-irradiation, produces a long-term radioprotection, demonstrated at both cytoarchitectural and motor levels.     

Dietary hypercholesterolemia aggravates contrast media-induced nephropathy

Background Contrast media administration can result in severe nephrotoxicity under pathological conditions such as diabetic nephropathy, congestive heart failure, dehydration, et al. The purpose of this study was to evaluate the effects of dietary hypercholesterolemia on contrast media-induced changes in renal function, blood flow, and histopathology.Methods Rats were fed either on a normal rodent diet ( group N) or a high-cholesterol supplemented diet ( group H; 4% cholesterol and 1% cholic acid) for 8 weeks. Half of the animals ( n = 6) from each diet group were then given a tail vein injection of 60% diatrizoate (6 ml/kg; group NC and group HC)and the other half were administered saline. Total serum cholesterol, triglyceride, serum creatinine,creatinine clearance rate, fractional excretion of sodium and potassium, and cortical nitric oxide production were determined one day following contrast media administration. Renal blood flow was determined by color Doppler flow imaging and pulsed-mode Doppler. Renal histopathology was observed by light microscopy.Results Total serum cholesterol and resistance indices of renal blood vessels increased significantly,while creatinine clearance rate and production of nitric oxide in the renal cortex decreased markedly in group HC and group H when compared to group N and group NC. The creatinine clearance rate decreased significantly in group HC compared to group H. Serum creatinine levels and fractional excretion of sodium and potassium in group HC were significantly higher than those in the other three groups. Severe tubular degeneration and necrosis, protein cast accumulation, and medullary congestion were found in group HC.Conclusion Hypercholesterolemia is a risk factor for contrast media-induced nephropathy.Hypercholesterolemia aggravates contrast media-induced nephrotoxicity through the reduced production of nitric oxide.     

关于我国医疗经纪人的思考

文章在阐明医疗经纪人含义的基础上,分析了医疗经纪人的作用和医疗经纪人在我国存在的必要性,通过对经纪人的分类和对我国医疗经纪人现状的研究,提出了发展壮大我国医疗经纪人队伍的几点建议.     

天然高分子磁微球作为靶向制剂的研究进展

磁性微球作为靶向药物载体有利于提高药物疗效，降低药物的毒副作用，为化疗药物的临床应用开辟了新途径。文章着重综述和评价了以天然高分子材料为载体的磁性微球的制备和应用，并对相关研究工作中存在的问题提出了看法。     

聚酰胺聚脲的合成及其性能

用聚脲对聚酰胺预聚体进行改性,以环氧氯丙烷进行交联制得聚酰胺聚脲(PAPU)抗水剂,该产物完全溶于水,其表观粘度为800~1 500 mPa.s,pH为5~7,固含量为(66±1)%。用凝固点降低法测得聚合物的数均分子量为1.55×104。研究了反应温度对产物表观粘度的影响。对聚合产物结构进行了红外和核磁表征,实验室制备产物的固含量与表观粘度较市售产品均有所增加。     

氨磷汀对化疗药物抗卵巢癌细胞的影响

目的评价细胞保护剂氨磷汀(amifostine)对不同化疗药物抗卵巢癌细胞的影响。方法用MTT法分别测定顺铂、长春新碱、依托泊甙和丝裂霉素对体外培养的Ho-8910肿瘤细胞系的抑制作用,实验组加化疗药前30 min经600mg.L-1氨磷汀处理,对照组不用氨磷汀处理,余同实验组,培养后比较两组细胞增殖的抑瘤率。结果实验组与对照组比较,两组肿瘤细胞抑制率无显著性差异(P>0.05)。结论氨磷汀不影响顺铂、依托泊甙、丝裂霉素和长春新碱对Ho-8910肿瘤细胞的抑制作用。     

肾脏错构瘤超声造影动态特性分析

目的研究对比脉冲序列造影成像技术（CPS）在肾脏错构瘤造影成像中的价值。方法对24例肾脏错构瘤患者（28个病灶）进行超声造影观察．分析其造影增强的图像特点。结果28个病灶均获得清晰的肿瘤动态造影灌注图像。肾脏错构瘤的造影特点表现多样，造影征象与肿瘤大小相关．小肿瘤（直径〈2cm）多表现为掩盖样快速强化，直径≥2cm的肿瘤多表现为慢速填充的造影征象。结论CPS清晰显示了肾脏错构瘤的血流灌注形态学特点，对≥2cm的肾脏错构瘤更能清晰显示其微循环灌注特点，有助于诊断和鉴别诊断。     

海洋抗癌活性物质最新研究概况

分类简要概述近年来源自海洋生物抗肿瘤药物的最新研究与开发,其中包括肽类、大环内酯类、生物碱类、萜类、多聚乙酰类、多烯醚类等。海洋抗癌活性物质在海洋天然产物研究中占据重要地位,大多具有新结构和新作用机制,其中许多化合物作为抗癌药物已进入临床前及临床研究阶段。     

STAT1对人肾透明细胞癌放射敏感性的影响

目的 研究人肾透明细胞癌信号传递和转录活化因子1(STAT1)表达情况及抑制STAT1对该肿瘤细胞放射敏感性的影响.方法 采用免疫组织化学染色技术对比检测34例人肾透明细胞癌标本和12例正常肾组织标本的STAT1表达.用Western blotting法检测离体培养人肾透明细胞癌细胞(CRL-1932)、纤维母细胞(CCL-116)和wilm's瘤细胞(CRL-1441)的STAT1表达.用氟达拉滨和siRNA抑制CRL-1932细胞STAT1表达,并通过成克隆法和台盼蓝染色计数法研究抑制STAT1对CRL-1932细胞放射敏感性的影响.结果 人肾透明细胞癌标本的总STAT1和磷酸化STAT1表达均明显高于正常肾组织.Western blotting法显示CRL-1932细胞STAT1表达比CRL-1441、CCL-116细胞明显增高;药物氟达拉滨能显著抑制CRL-1932细胞磷酸化STAT1的表达,并显著增加CRL-1932细胞的放射敏感性,且放射增敏程度与药物浓度呈正相关.经STAT1 siRNA处理后CRL-1932细胞总STAT1和磷酸化STAT1的表达均被有效抑制,且细胞在照射后的存活分数显著下降.结论 肾透明细胞癌STAT1呈高表达,抑制STAT1对该细胞有放射增敏作用.