对氯烯雌酚醚防治雌性大鼠去势后骨丢失的评价

目的：了解氯烯雌酚醚对去势雌性大鼠骨代谢的影响。方法：鼠龄７０天的Ｗｉｓｔａｒ雌鼠４８只，分别予假性手术与注射用油（ＳＶ组）、去势与注射用油（ＯＶ组）、假性手术与氯烯雌酚醚（ＳＥ组）及去势与氯烯雌酚醚（ＯＥ组）等处理，双侧卵巢去势或假性手术后７天，于每晚腹腔注射氯烯雌酚醚或注射用油４ｍｌ／ｋｇ，共４５天。处死大鼠时，测定子宫湿重，同时收集第１２胸椎和左胫骨制成脱钙骨切片，行骨组织形态计量学测定。结果：４组间子宫重量差异均有显著性。骨组织形态计量学显示，（１）ＯＶ与ＳＶ、ＳＥ及ＯＥ组间差异有显著性；（２）ＯＥ、ＳＥ和ＳＶ组间差异无显著性。结论：氯烯雌酚醚能抑制Ｗｉｓｔａｒ雌鼠去势后的骨丢失，减缓去势后的子宫萎缩，对骨骼有雌激素样的保护作用。     

Self-administration of GBR 12909 on a fixed ratio and progressive ratio schedule in rats

Intravenous self-administration of GBR 12909, an indirect dopamine agonist, was examined on a Fixed Ratio (FR 1) and a Progressive Ratio (PR) schedule of reinforcement in rats. Subjects were first trained to self-administer cocaine (1.5 mg/kg/inj) during daily 5 h sessions, after which GBR 12909 (0.187–1.5 mg/kg/inj) was substituted. On the FR 1 schedule, the inter-infusion interval for GBR 12909 self-administration was directly related to dose and was approximately three times longer than that established for equivalent doses of cocaine. Breaking points on the PR schedule were comparable for GBR 12909 and cocaine self-administration. The data indicate that, compared to cocaine, GBR 12909 has a longer duration of action and a similar reinforcing efficacy.     

维持肢体正常的运动感觉功能所需最少神经根数的实验研究

目的 研究臂丛神经根单发断，２根切断（不同方式联合）及３根切断后对肢体的影响，为治疗臂丛根性撕脱伤寻找更多的潜在移位神经，方法 ２５２只ＳＤ大鼠随机分为１３组：（１）第１－５组（单根神经根切断组）；每组１２只大鼠。分别切断Ｃ５－８Ｔ１各神经根；（２）第６－１２组（２根神经根切断组）；每组２４只大鼠。分别切断相邻及不相邻２根神经根，即Ｃ５，６，Ｃ６，７，Ｃ７，８，Ｃ８Ｔ１，Ｃ５，７，Ｃ６，８和Ｃ７Ｔ     

Effect of ethanol on sustained attention in rats

 Acute exposure to ethanol produces deficits in sustained attention in humans, but these attentional deficits have not been modeled in animals. In this study, an operant task was used to investigate the effects of low and moderate doses of ethanol on sustained attention in rats. Performance on a two-choice reaction time task over a 1-h session was assessed immediately following administration of ethanol (0.0, 0.5, 0.75, 1.0 and 1.5 g/kg IP). Each rat was required to respond to a light stimulus of variable duration (20, 100, and 500 ms) occurring at one of two locations. Under control and saline conditions, increases in stimulus length systematically increased choice accuracy and decreased reaction time. Ethanol produced a dose-dependent decrease in choice accuracy that interacted with time, with an initial impairment that was stimulus length-dependent followed by a general vigilance decrement. The data demonstrate that ethanol impaired the ability of rats to direct and sustain attention to brief, infrequent stimuli, and provide a model for further investigations into the underlying neurobiological mechanisms for ethanol-induced attentional deficits. Received: 19 March 1996 / Final version: 30 August 1996     

超氧化物歧化酶对大鼠肝脏缺血再灌注损伤保护作用的体外实验

目的：探讨氧自由基清除剂对大鼠肝脏缺血再灌注损伤的保护作用及其机理。方法：将Wistar大鼠分成三组，各组通过门静脉插管，对肝脏进行原位灌洗，心脏搏动组以4℃HTK液灌洗；心脏停跳组在心脏搏动停止60min后，以同样方法灌洗肝脏；SOD实验组灌洗方法同心脏停跳组，但灌洗液中含有超氧化物歧化酶（SOD）7500IU。灌注结束后，快速切取肝脏，于4℃HTK液中保存24h，然后在体外以Krebs-Henseleit缓冲液再灌注45min。测定再灌注过程中的门静脉压力，收集再灌注液，进行血气分析，测定其中丙氨酸转氨酶（ALT）、谷氨酸乳酸脱氢酶（GLDH）及脂质过氧化物（LPO）的含量；切取肝组织，检测其能量底物总和（TAN）及细胞凋亡情况。结果：再灌注期间，SOD实验组的门静脉压力为（6．4±0．9）cmH20，明显低于心脏停跳组的（12．1±0．7）cmH20（P〈0．01）。随着再灌注时间的延长，灌注液中AL]r和GLDH的浓度不断升高，但SOD实验组明显低于心脏停跳组（P〈0．05）。心脏停跳组肝脏氧消耗量明显低于心脏搏动组（P〈0．01），而SOD实验组氧消耗量明显增加（P〈0．01）。SOD实验组的TAN为（7．6±0．4）μmol／g，明显高于心脏停跳组的（5．3±0．7）,μmol／g（P＜0．05）。SOD实验组灌注液中LPO的含量为（0．42±0．10）nmol／g，明显低于心脏停跳组的（0．98±0．18）nmol／g（P＜0．01）。心脏搏动组只有极少量的肝窦内皮细胞和肝细胞凋亡，SOD实验组中凋亡细胞的数量也非常有限，而在心脏停跳组，则有大量的肝窦内皮细胞发生凋亡。结论：在体外，SOD能显著减轻大鼠肝脏的缺血再灌注损伤，这可能与SOD抑制了氧自由基所致的细胞凋亡有关。     

鸡和大鼠小脑发育的比较观察

观察发育阶段不同的鸡和大鼠的小脑标本外形,并在光学显微镜和电子显微镜下观察了结构。鸡卵在孵育的第6天,小脑原基出现。第15天小脑皮质形成,普肯野氏细胞(普氏细胞)排成一层。新生鸡小脑皮质发育近成年状态,普氏细胞发育基本完成。大鼠在生后第5天小脑皮质形成,第20天发育成熟。在生后第5天普氏细胞排成一层,第20天接近成熟状态,此时在电子显微镜下显示为粗面内质网和多聚核蛋白体区域性集中分布。鸡小脑比大鼠小脑发育早,这是种属差异。     

1α-Hydroxyvitamin D2 Partially Dissociates Between Preservation of Cancellous Bone Mass and Effects on Calcium Homeostasis in Ovariectomized Rats

Vitamin D metabolites can prevent estrogen depletion-induced bone loss in ovariectomized (OVX) rats. Our aim was to compare the bone-protective effects of 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), 1α,25-dihydroxyvitamin D₂ (1,25(OH)₂D₂), 1α-hydroxyvitamin D₃ (1α(OH)D₃), and 1α-hydroxyvitamin D₂ (1α(OH)D₂) in OVX rats. 1α(OH)D₃ and 1α(OH)D₂ are thought to be activated in the liver to form 1,25(OH)₂D₃ and 1,25(OH)₂D₂, respectively. Forty-four 12-week-old female Fischer-344 rats were either OVX or sham-operated (SHAM). Groups of OVX rats (n = 7 each) received vehicle alone, 1,25(OH)₂D₃, 1,25(OH)₂D₂, 1α(OH)D₃, or 1α(OH)D₂, starting 2 weeks after surgery. All vitamin D metabolites were administered orally at a dose of 15 ng/day/rat. Urine and blood samples were collected 6, 9, 12, and 16 weeks after surgery. Serum samples were analyzed for total calcium and phosphate. Calcium, phosphate, creatinine, and free collagen cross-links (ELISA) were determined in urine. After tetracycline double labeling, the rats were sacrificed 16 weeks postsurgery, and the proximal tibiae and the first lumbar vertebrae were processed undecalcified for static and dynamic bone histomorphometry. 1,25(OH)₂D₃ and, to a slightly lesser extent, 1,25(OH)₂D₂ elevated vertebral cancellous bone mass in OVX rats to a level beyond that observed in SHAM animals, and both compounds increased serum calcium and urinary calcium excretion to similar extents. 1α(OH)D₃ and 1α(OH)D₂ resulted in a 64% and 84%, respectively, inhibition of ovariectomy-induced vertebral cancellous bone loss. In the proximal tibial metaphysis, all vitamin D metabolites tested could only partially prevent post-OVX trabecular bone loss, with a tendency for 1α(OH)D₃ to be the least active compound. The effects of 1α(OH)D₃ and 1α(OH)D₂ on calcium homeostasis differed markedly, however. The mean increase in urinary calcium excretion over the whole experiment was fivefold for 1α(OH)D₃, whereas the corresponding increase for 1α(OH)D₂ was only twofold. We conclude that, compared with 1α(OH)D₃, 1α(OH)D₂ combined at least equal or higher bone-protective activity in OVX rats with distinctly less pronounced effects on calcium homeostasis. This effect was not due to a differential action of the corresponding main activation products, 1,25(OH)₂D₃ and 1,25(OH)₂D₂. Received: 2 May 1996 / Accepted: 18 October 1996     

Cocaine decreases self-control in rats: a preliminary report

Cocaine abuse is often associated with behavior that takes into account short-term, but not long-term consequences. However, there has been no empirical research concerning the effects of cocaine on self-control (choice of a larger, more delayed reinforcer over a smaller, less delayed reinforcer). In the present research, when food-deprived rats repeatedly chose between a larger, more delayed food reinforcer and a smaller, less delayed food reinforcer, chronic intraperitoneal injections of 15 mg/kg cocaine (but not 10 mg/kg fluoxetine) decreased the rats' choices of the larger, more delayed reinforcer. Cocaine can decrease rats' self-control.     

Effect of pentoxifylline on veno-occlusive priapism-induced corporeal tissule lipid peroxidation in a rat model

Objective: To investigate whether pentoxifylline could play a role in attenuation of the hazardous effects of ischemia/reperfusion on corporeal tissue in a rat model of veno-occlusive priapism (VOP). Materials and methods: Placebo and pentoxifylline were given to eight groups of rats prior to priapism being induced by a vacuum constrictive device for durations of 6 and 12 h, respectively. Half of the groups of rats that underwent the same duration of priapism (ischemic) were subjected to 1 h of detumescence after band removal (reperfusion). One group underwent no manipulation and no drug administration and served as a baseline determination (control). Corporeal homogenates were examined for lipid peroxidation (LP) derived malondialdehyde (MDA) accumulation via thiobarbituric acid assay. Results: MDA concentration differed significantly between VOP rats and controls (P < 0.001) but did not differ significantly between ischemic-only groups and reperfused groups (P > 0.05). In the pentoxifyllinepretreated groups, although MDA accumulation tended to be slightly lower than in the placebo groups, the difference was not statistically significant (P > 0.05) either in the 6- or 12-h duration priapic groups. Conclusions: LP, an indicator of radical oxygen metabolite (ROM) induced injury, occurs in rat corporeal tissue during and after abolishment of VOP. Single-dose pentoxifylline pretreatment failed to exert a protective effect on corporeal tissue in a rat model of VOP in terms of attenuation of LP.     

大鼠供肝冷缺血时间与肝移植术后受者肺损伤的关系

目的 探讨大鼠供肝冷保存时间与肝移植术后受者肺损伤的关系。方法 用Wismr大鼠建立原位肝移植模型，按供肝冷保存时间的不同分为5组（n=10），A组为假手术组，B组、C组、D组及E组的供肝冷保存时间分别为45min、90min、120min及180min。各组大鼠在移植肝恢复血流180min后处死，观察肺组织病理学变化，测定肺组织湿干重比值（W／D）、肺组织中髓过氧化氢酶（MPO）的活性，同时检测肝脏流出道血清肿瘤坏死因子（TNF-α）和白细胞介素18（IL-1β）的水平以及肺组织中TNF-α和IL-1β的表达。结果随着供肝冷保存时间的延长，肝脏流出道血清TNF-α和IL-1β水平及肺组织中TNF-α和IL-1β的表达均逐渐升高，肺组织W／D和MPO活性逐渐增高，肺损伤加重。结论供肝冷缺血时间与肝移植术后受者肺损伤相关，肺损伤随供肝冷缺血时间的延长而加重；血清中TNF-α和IL-1β升高及肺组织中TNF-α和IL-1β表达上调可能与肝移植后的肺损伤有关。