脊髓白质有髓和无髓神经纤维树脂切片的两种染色方法对比

目的介绍大鼠脊髓白质有髓和无髓神经纤维树脂切片的两种染色方法并比较其效果。方法灌注固定后从SD大鼠的椎管内取出脊髓,沿垂直于其长轴的方向切取2mm厚的组织块,制作甲基丙烯酸树脂包埋切片,分别用过碘酸一雪夫试剂一亮绿（PAS—G）以及过碘酸一雪夫试剂一苏木精（PAS—H）复合染色法,显示脊髓白质内的有髓和无髓神经纤维。结果两种染色方法所示有髓或无髓神经纤维的边缘,均被染成紫红色,清晰易辨。有髓神经纤维的轴突和髓鞘在PAS—G染色法中分别被染成绿色和粉红色,而在PAS—H染色法中均被染成淡蓝色。结论PAS—G复合染色法以及PAS—H复合染色法均可清晰显示脊髓白质内的有髓和无髓神经纤维,前者可更好地分辨轴突。     

放大倍数和包埋介质对睾丸组织体视学研究的影响

目的比较不同放大倍数和包埋介质对睾丸组织体视学研究的影响。方法不同放大倍数（10×、40×物镜和100×油镜）下观察石蜡（7μm）和甲基丙烯酸树脂（25μm）包埋的睾丸切片,利用体视学方法测量睾丸内生精小管、间质及间质内的空隙、生精细胞核的体积分数,以及生精小管和早期圆形精子细胞核的直径。结果不同放大倍数对生精小管体积分数的估计无显著性影响。与树脂切片相比,石蜡切片估计的生精小管的体积分数明显减少了16.9%～17.5%,生精小管直径、生精小管内生精细胞核的体积分数和早期圆形精子细胞核的直径分别明显减少了17.1%、26.6%和10.8%。石蜡切片睾丸内空隙的体积分数为20%～24%,而树脂切片几乎无这种空隙。结论放大倍数对睾丸组织绝大多数体视学参数估计无显著影响,而包埋介质影响较大。石蜡包埋使睾丸内各组织结构明显皱缩,生精小管之间出现明显空隙。     

小鼠肾脏发育中光镜和电镜的体视学分析

目的对小鼠肾脏发育中各组成结构进行体视学测量和分析,以提供小鼠肾发育的基础数据。方法应用光镜和电子显微镜技术结合体视学分析方法对小鼠肾脏发育各阶段的肾脏大体、各部组成、皮质肾小体及集合管上皮主细胞进行了详细观察和体视学测量与分析。结果大体测量：肾脏长度和体积生后1～7d、21～28d增加非常显著（P〈0．01）。光镜测量：皮质体积胚龄18d到生后1d增加非常显著（P〈0．01）;髓质体积生后1～14d、21～28d增加显著（P〈0．05）;内髓生后21d出现,以后体积变化不明显;皮质肾小体体积从胚龄18d到生后40d大约增大30倍。电镜测量：集合管上皮主细胞侧基底细胞膜面密度生后3W内迅速增长,截面积胚龄18d到生后7d增加显著。结论小鼠肾脏各部组成从胚龄18d开始体积迅速增长,到生后28d发育接近成年水平。     

正常大鼠小肠上皮内T细胞的形态计量学研究

目的研究TCRαβT细胞和TCRγδT细胞在大鼠小肠上皮内各肠段间的分布规律。方法采用免疫组化和体视学测量方法,对10只180~220 g的雄性W istar大鼠小肠上皮内T细胞的数密度、体积密度、表面积密度、平均体积和表面积体积比进行测量,并比较它们在各肠段间的差异。结果从十二指肠到回肠各肠段上皮内CD+3T细胞和TCRγδT细胞的体积密度、数密度和表面积密度均依次降低;各肠段上皮内TCRαβT细胞的体积密度、数密度和表面积密度则依次有增大的趋势;各肠段上皮内TCRγδT细胞的平均体积大于TCRαβT细胞的;各肠段上皮内CD+3T细胞、TCRαβT细胞和TCRγδT细胞的算术平均体积和细胞表面积体积比均变化不大,提示各肠段间同种T细胞的体积接近形状相似。结论总体上,从十二指肠到回肠大鼠小肠上皮内T细胞数依减少;而TCRγδT细胞的体积比TCRαβT细胞的大。     

甲氨基阿维菌素的致突变性、致畸性及亚慢性毒性的研究

目的与方法:本文报道了甲氨基阿维菌素小鼠骨髓嗜多染红细胞微核试验,小鼠精子畸形试验,Ames 试验,对大鼠的亚慢性毒性试验及致畸试验的研究结果。结果与结论:其剂量在6. 3～25. 2mg/ kg 的微核试验结果表明,各剂量组与阴性对照组的微核率比较,结果无显著意义( P > 0105) 。10～500μg/ 皿剂量组Ames 试验及15. 8～63mg/ kg. bw 剂量组小鼠精子畸形试验结果均为阴性。致畸研究结果表明,该药对大鼠无明显母体毒作用和胚胎毒作用。亚慢性毒性试验中,高剂量组雌性大鼠(9. 26mg/ kg. bw) 尿素氮、雄性大鼠(12. 6mg/ kg. bw) 尿素氮及白蛋白水平有一定程度的改变,雄、雌性大鼠肾脏脏器系数有显著的改变( P < 0105) 。雄性大鼠(12. 6mg/ kg. bw) 体重明显降低( P < 0105) ,比雌性大鼠影响略大。亚慢性毒性最大耐受剂量雌性大鼠为1. 16mg/ kg. bw ,雄性大鼠为1. 57mg/ kg. bw。     

碘缺乏、碘过多大鼠甲状腺结构的体视学研究

目的：研究碘缺乏与碘过多对Wistar大鼠甲状腺结构的体视学影响。方法：将Wistar大鼠随机分为三组,适碘组（对照组NI）、高碘组（HI）、低碘组（LI）,观察喂养24周甲状腺结构的体视学改变。应用MIAS－2000型图像分析系统,对大鼠甲状腺滤泡及滤泡胜进行形态定量测定及分析,每例分析150－200个滤泡及滤泡腔,获得7项体视学参数（平均体积、平均表面积、比表面积S／V、数密度Nv、体密度Vv、表面积密度Sv、球形因子SF）和1项滤泡截面积的定量参数。结果：低碘组滤泡及滤泡腔的SF、Vv均明显小于对照组,而S／V、Nv、Sv明显高于对照组,上皮细胞体积明显增大;高碘组滤泡在实验过程中无明显改变,而滤泡腔的均明显小于对照组,上皮细胞体积增大,滤泡的平均体积及平均表面积与对照组无明显差别,但偏大滤泡所占比例增多。结论：碘缺乏导致Wistar大鼠小滤泡增生性甲肿改变,而碘过多在本次实验中未形成甲肿,但随碘过多时间的延长,滤泡腔变小,上皮细胞增生肥大。     

人胎肾小球发育的定量研究

本文用体视学方法研究了５１例１３周至足月胎儿肾小球发育以及与此相关的肾脏体积、肾皮质体积及肾小体有关参数的变化。结果表明：肾脏体积、肾皮质体积、肾小球总数、总体积、肾小体总体积、总表面积均随胎龄呈指数增加；肾皮质体积密度和肾组织缩水系数随胎龄增加而趋于减小；肾小球和肾小体的数密度、体积密度及表面积密度随胎龄增大而增加；肾小球及肾小体截面平均直径、平均卡规直径和平均体积随胎龄增加趋于减小；皮质肾小球截面平均直径小于髓旁肾小球截面平均直径；肾小球的空间排布随胎龄增大趋于密集。     

放疗同步健择与顺铂化疗对大鼠脊髓损伤的实验研究

目的:探讨放射治疗同步顺铂(DDP)和健择(GEM)化疗对大鼠脊髓损伤的影响.方法:观察正常对照组、单纯放疗组、单纯化疗组(健择组、顺铂+健择组)与放疗联合化疗组(健择联合放疗组、顺铂+健择联合放疗组)的光镜和电镜下脊髓的形态学改变.结果:光镜下,单化组灰质出现白质部分脱髓鞘、变性、炎性细胞浸润,灰质结构疏松和血管增多,排列紊乱.单放组白质内神经纤维排列松散紊乱,部分白质出现细胞肿胀、坏死和炎细胞浸润,部分神经元尼氏体消失,神经胶质细胞固缩.化放组白质出现广泛脱髓鞘、炎细胞浸润、灰质血管增多和神经元固缩等改变.电镜下单化组脊髓髓鞘的髓板增厚、扭曲和皱缩;单放组髓鞘的板层结构松解、扭曲;化放组髓鞘轴索皱缩,髓鞘不规则分层且不规则增生,板层结构不明显.结论:不论健择单药还是健择和顺铂联合化疗均可引起大鼠脊髓损伤,放射治疗同步顺铂和健择化疗较单纯放疗加重对大鼠的脊髓损伤.     

缺碘大鼠甲状腺上皮细胞超微结构观察及其体视学研究

本文动态观察缺碘大鼠动物模型甲状腺上皮细胞超微结构的变化, 同时应用现代体视学技术量化形态学指标, 进行统计学分析。电镜下可见缺碘大鼠甲状腺上皮细胞线粒体、内质网扩张, 随着缺碘时间的延长线粒体进一步肿胀, 出现嵴断裂、缺失、空泡变性, 内质网扩张、膜断裂、脱颗粒。体视学测量结果显示, 线粒体的珡V 及-S均显著高于对照组, 而Nv 和S/V 均显著降低, 表明缺碘使线粒体体积增大, 被高度扩张的内质网包围的线粒体数量减少, 其数密度(Nv) 显著降低, 因此线粒体虽有扩张, 但其Vv 、Sv 仍相对降低。甲状腺上皮细胞中内质网珡V、-S、Vv 和Sv 显著高于对照组、S/V 显著降低, 表明缺碘使内质网高度扩张、体积增大; 扩张的内质网形状不规则, 致使其-S明显增大; 单位体积内内质网的数量减少, Nv 明显降低。本文结果提示, 形态学与体视学相结合为组织形态学研究提供了有效可行的方法学基础     

大鼠视网膜组织中线粒体的体视学定量研究

目的　研究线粒体在正常大鼠视网膜组织的变化特点及规律。方法　采用SD大鼠视网膜组织 ,用电镜和图像分析仪的方法 ,对视网膜组织中线粒体的进行体视学定量分析。结果　视网膜内节、外网状层及内网状层线粒体空泡的体积密度、表面积密度及内节与内网状层线粒体空泡的表面积与体积比差异均有显著性 ,并且线粒体的形状因子差异性较为明显 ,并按内节→外网状层→内网状层的顺序递增 ,从长杆状、椭圆形向圆形靠近。结论　视网膜内节线粒体产生的能量大 ,感光细胞所需能量多 ,功能活跃。视网膜外网状层线粒体产生的能量较内节少 ,双节细胞所需能量较感光细胞少 ,功能活动较内节差。视网膜内网状层线粒体产生的能量较少 ,表明神经节细胞活动不太活跃。     

Quantitative stereological studies of a 'selection' protocol of hepatocarcinogenesis following initiation in neonatal male and female rats

A modified initiation-selection procedure for neonatal male and female rat hepatocarcinogenesis were examined utilizing the methods of quantitative stereology. In this study, diethylnitrosamine (10 mg DEN/kg) was given a few days after birth. At weaning, the rats were fed 0.02% 2-acetylaminofluorene (AAF) for 2 weeks with a mitotic stimulus [70% partial hepatectomy (PH)] after 1 week on the diet. Quantitative stereological analyses in conjunction with the use of several enzyme markers were used to determine the number and volume of altered hepatic foci (AHF) detected at 1 week, 3 months and 7 months after the selection procedure. This format resulted in an equivalent number of AHF in male and female rats. The AHF were three times larger in males than in females 1 week after discontinuation of AAF administration. Three months after the selection procedure, the number of AHF had decreased by at least a third and their volume percentage was the same in male and female rats. After 7 months, the number and volume fraction of detectable AHF in females were comparable to those which had been observed at 1 week after selection. In the male, the number but not the volume fraction were similar at 7 months compared with 1 week after selection. Both initiation with DEN and selection with AAF/PH contribute independently to the total population of AHF in male and female rats. At least half of the AHF detected 7 months after the selection protocol were due to DEN administration alone. Rats receiving only the AAF/PH selection exhibited one third of the number of AHF observed with the complete protocol. Administration of a non-necrogenic dose of DEN to neonatal rats when coupled with the AAF/PH selection procedure resulted in a significant promotion of the growth of initiated hepatocytes at 1 week, 3 months or 7 months after the selection procedure. These studies demonstrated that (i) the number of AHF detected after a non-necrogenic dose of DEN during the first week of life with subsequent AAF/PH selection after weaning decreases within the first 3 months after the selection procedure, but can re-develop with a promotion stimulus; (ii) the AAF/PH selection procedure itself may initiate hepatocytes in the absence of DEN administration; (iii) the AAF/PH selection procedure is equally effective with respect to the number of AHF observed after phenobarbital promotion in weaning male and female rats initiated near birth.      

Reduction of potential for replicative but not unscheduled DNA synthesis in hepatocytes isolated from aged as compared to young rats

Replicative DNA synthesis of hepatocytes obtained from 2- to 3-month-old and 28- to 30-month-old rats was examined in primary culture under serum-free conditions to clarify whether observed age-related changes in DNA replication depend exclusively on intracellular events, or whether humoral factors are involved. Hepatocyte replicative DNA synthesis of the aged rats was significantly lower (less than one tenth, P less than 0.001) than that of 2- to 3-month-old rats. EGF receptor assays, however, revealed no difference in either number or affinity of the cell surface receptors between hepatocytes from aged as opposed to young rats. Furthermore, sera obtained from aged rats did not demonstrate any inhibitory effect on DNA synthesis of young rat hepatocytes. After treatment with N-hydroxy acetylaminofluorene, N-nitroso-N-methylurea, or 254-nm UV irradiation degree of resultant UDS was similar in hepatocytes from both young and aged animals. Thus, while the results suggest that potential for DNA replication markedly diminishes with age, DNA repair systems are well preserved.     

顺铂和盖诺化疗对脊髓损伤的实验研究

目的观察顺铂和长春瑞滨对脊髓损伤的影响,为临床治疗减低毒副作用提供理论依据。方法通过光镜、电镜观察脊髓的形态学改变;采用免疫组化方法检测引起脊髓损伤相关基因蛋白的变化。结果盖诺和顺铂＋盖诺均可引起脊髓的损伤,但顺铂＋盖诺对脊髓的损伤要重于单用盖诺,即灰质出现血管增多、神经元固缩等改变,白质内部分有髓神经纤维脱髓鞘改变,髓板增厚、扭曲、皱缩,部分结缔组织排列紊乱,其凋亡因子bax及caspase-3、炎症因子IL-1β、iNOS在脊髓损伤各组均有过表达,且联合治疗组明显高于单药组（P〈0．05）。结论不论盖诺还是顺铂＋盖诺都能引起脊髓损伤,其损伤机制与bax、caspase-3、IL-1β与iNOS基因蛋白过表达有关。     

Activity of O6-alkylguanine-DNA alkyl transferase in the liver, kidney and white blood cells of rats of different ages.

Age-related differences in the sensitivity of rats to alkylating carcinogens may be dependent on various factors, including the cellular levels of O6-alkylguanine-DNA alkyltransferase (AT). In the present study, the levels of AT were measured in protein extracts prepared from liver, kidney and peripheral white blood cells of male outbred rats aged 1, 4, 14, 22 and 36 months. The AT level (expressed as activity per milligram protein) in liver extracts was lower in rats aged 1, 4 or 36 months than in extracts prepared from rats aged 14 or 22 months. This observation of a variation in AT level with age is in agreement with our previous results. The AT levels in kidney and white blood cells did not differ significantly with age, and in all cases the AT levels were lower than those observed in the liver extracts, the kidney extracts having more AT activity than the white blood cell extracts. The total protein content of both liver and kidney tissues, calculated per gram of wet tissue, increased to a maximum at 14 months and subsequently declined, the total protein content being always higher in the liver than in the kidney. In contrast, the DNA content per gram of wet tissue was highest in young animals and subsequently declined to a minimum at 14 months. The implications of this inverse relationship to the levels of AT activity are discussed.     

Cisplatin-induced autonomic neuropathy: does it really exist?

The neurotoxic side-effects of cisplatin affect predominantly the large, myelinated fibres of peripheral nerves, leading to a sensory neuropathy. Several reports of cisplatin-associated autonomic neuropathy have been published. Autonomic dysfunction however, is caused by a neuropathy of small unmyelinated nerve fibres.By using the absolute pupil diameter as a parameter of autonomic nervous system function, we studied autonomic neuropathy in the eye of cisplatin-intoxicated rats. In addition, we examined autonomic cardiovascular function by measuring the change in heart rate (HR) and mean arterial blood pressure (MAP) in response to intravenous phenylephrine (PHE) and tyramine (TYR). No significant differences in mean pupil diameter developed in cisplatin-intoxicated rats (n = 12) in the course of 9 weeks (total cumulative dose cisplatin 18 mg/kg) compared with normal controls (n = 9) (MANOVA, F_1,19 = 0.88, P < 0.36). The PHE- and TYR-induced changes in MAP and HR were virtually the same in cisplatin-intoxicated rats when compared with normal controls.We conclude that cisplatin probably does not cause autonomic dysfunction, at least not in rats, in doses commonly used and which are known to cause a peripheral, sensory neuropathy.     

Study of the post-natal effects of chemopreventive agents on ethylnitrosourea-induced transplacental carcinogenesis in rats. II. Influence of low-molecular-weight polypeptide factors from the thymus, pineal gland, bone marrow, anterior hypothalamus, brain cortex and brain white substance

The influence of the polypeptide factors extracted from thymus,pineal gland, bone marrow, anterior hypothalamus, brain cortexor brain white substance on N-ethyl-N-nitrosourea (ENU)-inducedtransplacental carcinogenesis was studied in rats. ENU was givento pregnant rats as a single i.v. exposure at a dose of 75 mg/kgbody weight on the 21st day of gestation. The polypeptide factorswere given to the offspring as a series of s.c. injections,at a dose of 0.5 mg/rat/day, starting at one or 2.5 months ofage and continuing throughout the whole of post-natal life.ENU induced tumors of the brain, spinal cord, peripheral nervesand kidneys in 94-98% of the offspring exposed to the carcinogen,with an average number of 2.3-2.6 tumors per rat, and an averagesurvival time of 294 days. Post-natal thymus factor or pinealgland factor administration was followed by an increase in meanlifespan of 2 months and a significant decrease (P < 0.05)in the total tumor number per tumor-bearing rat, as well asthe incidence and multiplicity of spinal cord tumors. Pinealgland factor also decreased the incidence of peripheral nerveand kidney tumors and their number per tumor-bearing rat. Braincortex factor and brain white substance factor treatment wasfollowed by a decrease in total tumor multiplicity of 1.2- to3.3-fold, and a decrease in incidence of brain tumors of 10to 33% per rat in comparison to the controls. Brain cortex factoralso decreased the total tumor incidence. At the same time,brain white substance factor administration increased the incidenceof peripheral nerve tumors and decreased the mean lifespan.Both bone marrow factor and anterior hypothalamus factor didnot have any modifying effects on any of the ENU-induced tumorsand mean lifespan. Thus, our results show the possibility ofattenuation of transplacental ENU-induced carcinogenesis withpost-natal administration of some polypeptide substances.     

DNA alkylation by nitrosobis-(2-oxopropyl)amine in rats of different ages

We have examined the methylation of liver DNA (O6- and N7-methylguanine) by nitrosobis-(2-oxopropyl)amine (BOP) in male and female rats at various ages, following treatment with 2.5 mg of BOP; this dose given twice weekly for 30 weeks induces tumors in all animals. Except in young rats there was more methylation in female rat liver than in male rat liver, when adjusted for different sizes of the animals. There were differences in the extent of methylation between young (4 weeks) and older rats, but not between young adult (20 weeks) and old adult (65 weeks) males; the latter developed liver tumors when treated with BOP, and the former did not. There was no obvious relation between increased susceptibility to liver tumor induction by BOP and the extent of alkylation of liver DNA. Methylation of DNA was lower in the kidney than in the liver and, here, there was little difference between the sexes. In the testis there was N7-methylation of guanine in DNA, but no O6-methylguanine was detected.     

Declining melatonin levels and MT1 receptor expression in aging rats is associated with enhanced mammary tumor growth and decreased sensitivity to melatonin

Serum melatonin (MLT) levels have been reported to diminish significantly by the 5th and 6th decades of life as the incidence of breast cancer increases. Given MLT’s anti-cancer activity, we hypothesize that age-related decline in pineal MLT production leads to enhanced breast cancer development and growth as women age. In this study, we sought to determine whether the growth of tissue-isolated mammary tumors in young, adult, and old female Buffalo rats relates to the age-related changes in MLT and its MT1 receptor. Significant decreases in the peak nighttime serum MLT levels were observed in old as compared to adult and young rats. Significantly diminished nighttime and early morning levels of MT1-melatonin receptors were observed in uteri from old rats compared to adult and young rats. Growth rates in transplanted, tissue-isolated, carcinogen-induced mammary tumors are significantly increased in old rats as compared to adult or young rats. The growth-suppressive actions of exogenous MLT are diminished in old rats compared to adult and young rats. This decrease in tumor response correlates with reduced expression of the MT1 receptor in old as compared to young and adult rats. Thus, enhanced mammary tumor growth is associated with old age and diminished levels of MLT and MT1 receptor during old age, resulting in reduced sensitivity to exogenous MLT. Finally, our studies demonstrate that the tissue-isolated tumor model is viable model system in which to study the role of aging on breast cancer growth.