Spontaneous teratoma in a Sprague-Dawley rat

An 6-week-old male Sprague-Dawley rat which had undergone no experimental treatment died from enlargement of the abdomen. At necropsy, a spherical mass measuring about 3 X 4cm in diameter was connected to the retroperitoneal region cross to the middorsal line of the body. The tumor was composed of skin, ganglion, striated and smooth muscle, cartilage, bone, pancreas, glands, lymph node, and fibrous and adipose tissue, and diagnosed as teratoma.     

A supernumerary forelimb in a Wistar rat

A fifth limb, quite independent of the others, was found in a pup born in our colony of Wistar rats. The malformation is described.     

Spontaneous liver tumors in aged germfree Wistar rats.

Liver tumors, ranging from benign nodules to carcinomas, developed spontaneously in 115 (87%) of 132 germfree Wistar rats beyond the age of 30 months. In addition, the rats developed a high incidence of benign adenomas of endocrine glands and of the breasts.     

Wistar大鼠心脏自发性病变的病理学观察

目的了解Wistar大鼠心脏自发性病变发病情况,为长期致癌性研究、老年病学研究及毒性病理学提供背景资料。方法采用160只清洁级Wistar大鼠,雌雄各半,常规饲养,分别在9月龄、12月龄、18月龄、24月龄时处死40只大鼠,HE及Masson三色法染色,观察心脏的病理改变。结果 9月龄Wistar大鼠心脏未见明显病理改变;12月龄Wistar大鼠月龄心脏病变的发病率为2.5%（1/40）,表现为少数心肌细胞变性坏死伴少量以单核细胞为主的炎细胞浸润;18月龄大鼠心脏病变的发病率为57.5%（23/40）,表现为轻至中度心肌病,雄性发病率高于雌性。24月龄大鼠100%（40/40）出现不同程度的心肌病,并有2.5%（1/40）发生心内膜下纤维组织增生。Masson染色显示9月龄大鼠心脏血管周围及心脏瓣膜环下有少量胶原纤维,随年龄增长,血管周围及心脏瓣膜环下胶原纤维逐渐增多,并延伸入心肌细胞间。结论随年龄增长,大鼠心脏自发病变比率升高,主要病变为心肌病,偶尔可发生心内膜下纤维组织增生;胶原纤维沉积首先发生于血管周围及心脏瓣膜环下,随年龄增长而增多,可能与大鼠心肌病的的发生密切相关。     

Immuno-corticotropin interactions in a nociceptive environment in the Wistar rat

In pregnant rats, oral administration of ammonium nitrate, stress with ether and antigenic stimulation were found to induce immune variations, hormonal changes and evince the organism's capacities of detoxification. An activation of the immune system and immunosuppression have been recorded respectively during xenobiotics administration and antigenic stimulation, and during stress. Corticotrophe response occurred on the 6th day of gestation and was more pronounced from the 12th day onwards in animals receiving ammonium nitrate. At the end of the gestation period, however, the corticotrophe response became stable in treated animals. Ammonium nitrate administration seemed to drive a major toxicity effect, clearly observed through increased levels of methemoglobine and coincided with a significant decrease in the level of glutathione, confirming a mechanism of detoxification.     

Wistar大鼠的自发肿瘤病变及其发生率

目的了解Wistar大鼠的各种自发性肿瘤病变及其发生率。方法致癌实验中的对照组,采用4周龄SPF级Wistar大鼠,雌、雄性大鼠各60只,实验前观察1周,常规饲料喂饲104周后处死,进行组织病理学检查。结果报告了Wistar大鼠的各种自发性肿瘤病变及其发生率。雄性大鼠中发生肿瘤的动物占49.12%,发生良性肿瘤的动物占38.60%、发生恶性肿瘤的动物占17.54%;良性肿瘤主要有垂体腺瘤(19.30%)、睾丸间质细胞瘤(5.26%)和皮下纤维瘤(5.26%);恶性肿瘤主要有鳞状细胞癌(7.02%)和淋巴造血系统肿瘤(3.51%)。雌性大鼠中发生肿瘤的动物占60.34%;发生良性肿瘤的动物占50.00%、发生恶性肿瘤的动物占15.52%;良性肿瘤主要有乳腺纤维腺瘤(25.86%)和垂体腺瘤(24.14%);恶性肿瘤主要有腺癌(5.17%)和乳腺癌(3.45%)。结论本文报告的Wistar大鼠自发肿瘤及其发生率进一步丰富了现有SPF级Wistar大鼠自发性肿瘤的数据资料,可为有关技术人员提供一定的参考和借鉴。     

Ribavirin-induced sperm shape abnormalities in Wistar rat

Ribavirin (1-β-d-ribofuranosyl-1,2,4, triazole-3 carboxamide) is a broad-spectrum antiviral drug. This study was aimed to investigate the mutagenicity of ribavirin on germ cells by employing sperm morphology assay. Male Wistar rats were treated with water, cyclophosphamide (CP) 40 mg/kg, and ribavirin 20, 100 and 200 mg/kg (i.p.) for 5 consecutive days at intervals of 24 h. Following the last exposure, at 14, 28, 35, 42 and 70 days, the epididymal sperm smears were obtained and stained according to the standard procedure. One thousand sperms per animal were classified into normal and different abnormal types. Both CP and ribavirin-induced anomalies of head and tail of sperm except at 70 days. In CP groups, maximum incidence was observed at 28, 35 and 42 days. Ribavirin 20 mg/kg induced maximum incidence at 14 and 42 days, 100 mg/kg at 28 and 42 days and 200 mg/kg at 28-42 days. These results show that ribavirin is mutagenic to rat germ cells in a transient fashion.     

Spontaneous and conditioned behavior of Wistar and Long Evans rats

Spontaneous behavior (locomotion, feeding, drinking, and exploration in a two box apparatus) as well as conditioned behavior (passive and active avoidance responding, and freezing in the light-dark box apparatus) were studied in naive male Wistar and Long Evans rats. Concerning spontaneous behavior, Long Evans rats were more active during both light and dark periods, and showed better exploratory performance than Wistar rats. Concerning conditioned behavior, Long Evans rats acquired and retained better active and passive avoidance responses, and exhibited longer initial freezing than Wistar rats in the range of 0.6-1.4 mA footshocks. The results better define the important behavioral differences existing between the two strains, Long Evans rats showing consistently a higher level of alertness and a better conditioned performance.     

Spontaneous pineal body tumours (pinealomas) in Wistar rats; a histological and ultrastructural study

The pathology of 5 cases of pinealomas in Wistar rats used in long-term toxicological studies is described both grossly, microscopically and ultrastructurally, together with a review of the related literature.     

Wistar大鼠自发性乳腺肿瘤细胞系的建立及其生物学特性

目的 从Wistar大鼠自发性乳腺肿瘤中分离出乳腺肿瘤细胞系(ZHL2006),并对其进行鉴定,为动物模型的开发、肿瘤发病机制的探讨提供有价值的线索.方法 对一例Wistar大鼠自发性乳腺腺癌瘤组织进行培养.对传代培养细胞进行细胞生长曲线测定、细胞形态结构分析、细胞染色体分析,检测广谱细胞角蛋白(PCK)表达、软琼脂集落形成实验等检测.将细胞接种于10只裸鼠,并对形成的肿瘤进行病理组织学检查,并进行分离培养.结果 ZHL2006细胞在体外生长迅速,群体倍增时间为43.6 h;倒置显微镜及Giemsa染色镜下观察细胞为多边形及梭形;透射电镜观察可见细胞表面有微绒毛,核高度不规则,核浆比例增大,核仁明显等;染色体数目和结构异常,具有癌细胞特性.广谱细胞角蛋白(PCK)染色阳性,说明其自上皮而非来自基质;同时ZHL2006细胞系在软琼脂中可形成克隆,具裸鼠致瘤性.该乳腺肿瘤细胞系经体外长期培养后已形成永生化细胞系,并具有明显的恶性细胞表型.裸鼠接种实验成功率为6/10,复制肿瘤细胞和原发肿瘤形态结构一致,细胞培养形态结构一致.结论 本研究成功的建立了大鼠乳腺肿瘤细胞系,该细胞系具有典型的恶性肿瘤特征,能应用于裸鼠并成功复制出乳腺肿瘤模型.     

Acetylcholinesterase from Wistar rat brain.

Acetylcholinesterase (E.C.3.1.1.7) was partially purified from rat brains stored in toluene. Extraction was performed using buffers containing non-ionic tensoactive detergents. Some properties of the enzyme were affected by the use of different activity measurement methods, such as the short-time radiometric or the long-time colorimetric method. There were two zones of maximum activity in the range pH 7.5-8.0 and 8.0-8.6, respectively. There seems to be a histidine residue in the enzyme that participates in the catalytic process. Thermal denuration presented first order kinetics and different thermodynamic parameters were obtained on using different incubation periods. On using the short-time activity measurement method there was activation at high substrate concentration, but with the long time method there was a marked inhibition produced by excess of substrate. However, if the enzyme was extracted from fresh rat brain, toluene untreated, these differences dissapeared. Gel filtration and disc electrophoresis showed the presence of multiple and interconvertible forms of the enzyme.     

Spontaneous otitis media in Wistar rats: an overlooked pathology in otological research

The rat is commonly employed in otological research, but spontaneous ear infections can confound the results of experimental procedures--wasting time, money, and animals. The authors focus on the incidence of spontaneous otitis media in Wistar rats. They compare disease incidence in animals housed in standard cages with those housed in barrier units, showing that 20% of their conventionally housed animals developed spontaneous otitis media, whereas only 5% of their animals housed in isolated units were infected. These results underscore the importance of strict control of the shipping, housing conditions, and manipulation of animals to be used in otological research.     

Ribavirin-induced sperm shape abnormalities in Wistar rat.

Ribavirin (1-beta-D-ribofuranosyl-1,2,4, triazole-3 carboxamide) is a broad-spectrum antiviral drug. This study was aimed to investigate the mutagenicity of ribavirin on germ cells by employing sperm morphology assay. Male Wistar rats were treated with water, cyclophosphamide (CP) 40 mg/kg, and ribavirin 20, 100 and 200 mg/kg (i.p.) for 5 consecutive days at intervals of 24h. Following the last exposure, at 14, 28, 35, 42 and 70 days, the epididymal sperm smears were obtained and stained according to the standard procedure. One thousand sperms per animal were classified into normal and different abnormal types. Both CP and ribavirin-induced anomalies of head and tail of sperm except at 70 days. In CP groups, maximum incidence was observed at 28, 35 and 42 days. Ribavirin 20 mg/kg induced maximum incidence at 14 and 42 days, 100 mg/kg at 28 and 42 days and 200 mg/kg at 28-42 days. These results show that ribavirin is mutagenic to rat germ cells in a transient fashion.     

Intraocular teratoma in a mouse

A 4.5-month-old male B6.129S2-Trp53tm1Tyj mouse developed an enlarged left eye. After euthanasia, the eye was removed and found to contain a teratoma composed of smooth muscle, white fat, neural tissue, and villous intestinal epithelium with appearance similar to that of the small intestine. Many normal intraocular structures were absent. To our knowledge, this represents the first reported intraocular teratoma in a mouse.