慧星试验检测洛克沙胂对CHL细胞的DNA损伤

利用碱性单细胞凝胶电泳技术研究洛克沙胂对中国仓鼠肺细胞(CHL)的DNA损伤影响。洛克沙胂分为10、100、500、1000mg/L剂量组,分别以磷酸盐缓冲液和10mg/L亚砷酸钠为对照组,经3、6、12、24、48h暴露后进行单细胞凝胶电泳。结果表明,慧星试验参数尾DNA含量、慧星全长、慧尾长、尾距和Olive尾距等表现出剂量-效应、时间-效应关系,不同剂量洛克沙胂、不同暴露时间下对CHL细胞有不同程度的DNA损伤。     

Detection of radiation-induced apoptosis using the comet assay

The electrophoresis pattern of apoptotic cells detected by the comet assay has a characteristic small head and spread tail. This image has been referred to as an apoptotic comet, but it has not been previously proven to be apoptotic cells by any direct method. In order to identify this image obtained by the comet assay as corresponding to an apoptotic cell, the frequency of appearance of apoptosis was examined using CHO-K1 and L5178Y cells which were exposed to gamma irradiation. As a method for detecting apoptosis, the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay was used. When the frequency of appearance of apoptotic cells following gamma irradiation was observed over a period of time, there was a significant increase in appearance of apoptosis when using the TUNEL assay. However, there was only a slight increase when using the comet assay. In order to verify the low frequency of appearance of apoptosis when using the comet assay, we attempted to use the TUNEL assay to stain the apoptotic comets detected in the comet assay. The apoptotic comets were TUNEL positive and the normal comets were TUNEL negative. This indicates that the apoptotic comets were formed from DNA fragments with 3'-hydroxy ends that are generated as cells undergo apoptosis. Therefore, it was understood that the characteristic pattern of apoptotic comets detected by the comet assay corresponds to cells undergoing apoptosis.     

Prediction of cellular radiosensitivity from DNA damage induced by gamma-rays and carbon ion irradiation in canine tumor cells

Diseases of companion animals are shifting from infectious diseases to neoplasms (cancer), and since radiation therapy is one of the effective choices available for cancer treatment, the application of radiotherapy in veterinary medicine is likely to increase. However tumor tissues have different radiosensitivities, and therefore it is important to determine the intrinsic radiosensitivity of tumors in individual patients in advance of radiotherapy. We have studied the relationship between the surviving cell fraction measured by a clonogenic assay and DNA double strand breaks detected by a comet assay under neutral conditions in three canine tumor cell lines, after gamma-ray and carbon ion irradiation. In all the cell lines, cell death assessed by the clonogenic assay was much higher following irradiation with carbon ions than with gamma-rays. The initial and residual (4 hr) DNA damage due to gamma-ray and carbon ion irradiation were higher in a radiosensitive cell line than in a radioresistant cell line. The surviving cell fraction at 2 Gy (SF2) showed a tendency for correlation with both the initial and residual DNA damage. In particular, the residual damage per Gy was significantly correlated with SF2, regardless of the type of radiation. This indicates that cellular radiosensitivity can be predicted by detection of radiation-induced residual DNA damage.     

Intrinsic radiosensitivity and repair of sublethal radiation-induced damage in canine osteosarcoma cell lines

OBJECTIVE: To characterize the radiosensitivity and capacity for sublethal damage repair (SLDR) of radiation-induced injury in 4 canine osteosarcoma cell lines. SAMPLE POPULATION: 4 canine osteosarcoma cell lines (HMPOS, POS, COS 31, and D17). PROCEDURES: A clonogenic colony-forming assay was used to evaluate the cell lines' intrinsic radiosensitivities and SLDR capacities. Dose-response curves for the cell lines were generated by fitting the surviving fractions after radiation doses of 0 (control cells), 1, 2, 3, 6, and 9 Gy to a linear quadratic model. To evaluate SLDR, cell lines were exposed to 2 doses of 3 Gy (split-dose experiments) at an interval of 0 (single 6-Gy dose), 2, 4, 6, or 24 hours, after which the surviving fractions were assessed. RESULTS: Mean surviving fraction did not differ significantly among the 4 cell lines at the radiation doses tested. Mean surviving fraction at 2 Gy was high (0.62), and the alpha/beta ratios (predictor of tissue sensitivity to radiation therapy) for the cell lines were low (mean ratio, 3.47). The split-dose experiments revealed a 2.8- to 3.9-fold increase in cell survival when the radiation doses were applied at an interval of 24 hours, compared with cell survival after radiation doses were applied consecutively (0-hour interval). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that these canine osteosarcoma cell lines are fairly radioresistant; alpha/beta ratios were similar to those of nonneoplastic, late-responding tissues. Future clinical investigations should involve increasing the fraction size in a manner that maximizes tumor killing without adverse effects on the nonneoplastic surrounding tissues.     

Acute bacterial cystitis does not cause deoxyribonucleic acid damage detectable by the alkaline comet assay in urothelial cells of dogs

Considering the high incidence of dogs with acute bacterial cystitis (BC) and the relationship among inflammation, genotoxicity, and carcinogenesis, we conducted a case-control study comparing the frequency of deoxyribonucleic acid (DNA) lesions assessed by the comet assay between disease-free animals (13 males and 13 females) and cytology-confirmed cases of acute BC (12 males and 12 females), which was mainly caused by Staphylococcus sp. (40%) and Escherichia coli (35%). The results show no increase in DNA damage in cells obtained by bladder washings and no influence of age, sex, and breed due to acute BC. In conclusion, DNA damage was seemingly not associated with the infection by specific bacteria.     

The Comet assay for detection of DNA damage in canine sperm

Sperm DNA integrity is a fundamental prerequisite in fertilization and embryo development. Among DNA integrity tests, the Comet assay is an accurate and sensitive test for the detection of sperm oxidative damage. The aim of this work was to evaluate sperm oxidative damage using the Comet assay and to study the correlation between Comet and routine assays for the evaluation of semen quality. Dogs were divided in two groups: group A (n = 6), comprising dogs with abnormal spermiogram, that is astheno‐, terato‐ or oligoasthenoteratozoospermic (OAT); and group B (n = 8), comprising normospermic dogs. The distribution of sperm oxidative damage was significantly different between the two groups (p = .001): group A—median: 31.55%, interquartile range (IQR): 30.18–38.01; group B—median: 0.90%, IQR: 0.65–1.96. The correlation between oxidative damage and abnormal morphology was high (r = .846; p < .001). There was a negative correlation between progressive motility and oxidative damage (r = ?.792; p = .001). Basal and oxidative DNA damage of spermatozoa are increased in dogs with non‐normospermic semen. In conclusion, and considering the elevated correlation with classical tests of sperm quality, the Comet assay has ample potential for clinical and research purposes in dogs.     

The relationship between the hemagglutination-inhibition test and the enzyme-linked immunosorbent assay for the detection of antibody to Newcastle disease

An assay of 364 chicken serum samples for Newcastle disease virus antibodies determined that a commercial NDV enzyme-linked immunosorbent assay (ELISA) had a 98.2% sensitivity and a 91.7% specificity relative to the NDV HI test. The ELISA values regressed significantly (F = 930, df = 1/362, P less than 0.001) on the hemagglutination-inhibition (HI) titers. The correlational coefficient was 0.85. For individuals, two tests can have the same result based upon chance alone. Kappa is a measure of agreement between two tests that corrects for this chance agreement. The kappa between the ELISA and HI test was calculated to be 0.84 (Z = 7.74, P = 0.00001), which indicates a highly significant agreement between the two tests.     

果洛州玛沁县草原毛虫虫害发生与气候因子的相互关系

利用玛沁县历年草原虫口密度调查资料,研究了气候因子尤其是温度与降水对草原毛虫(Gynaephora alpherakii)虫害发生的影响。结果表明,果洛州玛沁县草原毛虫的灾害严重,危害面积达14.67×104 hm2,1993年最高虫口密度达500头·m-2,2003年也较为严重;1971－2007年的37年间玛沁县的年平均温度呈升高趋势,降水量呈递减趋势;虫口密度与年平均温度、虫口密度与年降水量、虫口密度与年平均温度和年降水量之间均无显著关系（P>0.05）。虫口密度与前一年9月的降水量关系显著（P<0.05）,与前一年9月平均温度、降水量二者关系显著,虫害的发生与前一年9月的水热条件密切相关,温度与降水适宜会使草原毛虫大量发生,导致严重虫害。本研究的结果与其他研究分析认为的“温度是草原毛虫生长发育的限制因素”这一结论并不完全一致,这是因为玛沁县近年来温度升高与降水减少,使得温度不再是限制因素,而草原毛虫进行羽化、交配、产卵、孵化所需求的9月降水量成为影响虫害发生的关键因素。     

镉诱导仔猪睾丸支持细胞氧化酶活性降低及DNA的损伤

以仔猪睾丸支持细胞为试验模型,采用二步酶消化法分离支持细胞进行培养。探讨了0、10、20、40、80μmol/L的氯化镉对支持细胞的毒性作用。结果表明:10μmol/L以上的氯化镉有抑制支持细胞生长的作用,并能使支持细胞氧化酶活性下降,造成支持细胞DNA的损伤。     

A possible relationship between viral infection and chromosome damage in breeding boars

A cytogenetic analysis of peripheral blood lymphocytes was carried out on breeding boars (n = 5) on a farm where viral infections (porcine parvovirosis) had occurred. Several different types of chromosomal aberrations were observed including chromatid breaks (23.60 +/- 2.88%), exchanges (9.60 +/- 8.99%), and fragments (4.26 +/- 3.31%). In addition, 2.94 +/- 1.74% of cells in metaphase showed pulverization. Cells with multiple aberrations were seen in two of five boars. The chromosomal damage in the boars may have been induced by a genotoxic agent such as a viral infection, and may also be related to the reproductive impairment of the pigs.     

DNA damage and decrease of cellular oxidase activity in piglet Sertoli cells exposed to arsanilic acid

The study was designed to explore the toxic effects of arsanilic acid on piglet Sertoli cells. Sertoli cells were isolated from piglet testes using a two-step enzyme digestion followed by differential plating. Piglet Sertoli cells were cultured and classified into the following five groups: group A, the control without arsanilic acid treatment; group B, cultured with 5 μM arsanilic acid; group C, cultured with 50 μM arsanilic acid; group D, cultured with 0.5 mM arsanilic acid; and group E, cultured with 5 mM arsanilic acid. We found that Sertoli cell growth was inhibited by arsanilic acid at 0.5 mM compared with the control, group A. The oxidase activity of Sertoli cells was decreased by arsanilic acid at 0.5 mM as evidenced by the observations that arsanilic acid increased MDA content but decreased the SOD and GSH-Px activities of Sertoli cells. Moreover, 50 μM of arsanilic acid was observed to cause DNA damage in Sertoli cells. The results of our study suggest that exposure of Sertoli cells to arsanilic acid leads to induction of oxidative stress and inhibition of cell growth at a high concentration, while arsanilic acid causes DNA damage in Sertoli cells at a low concentration.     

球虫病与维生素的关系

鸡球虫病是由艾美尔科、艾美尔属的各种球虫寄生于鸡肠道上皮细胞所引起的以肠炎、消瘦、贫血、生产性能降低和下痢带血为主要症状的寄生虫病.危害我国养禽业发展的主要是柔嫩、毒害、巨型、堆型和布氏艾美尔球虫.笔者现结合实践经验,论述一下球虫病与维生素的关系,仅供参考.     

Isolation of Cowdria ruminantium by cellular affinity chromatography and detection by an enzyme-linked immunosorbent assay

The isolation of Cowdria ruminantium by means of wheat germ lectin affinity chromatography as described in this paper permits the recovery of partially purified viable organisms under mild conditions in short time. These conclusions are based upon results of analyses of column fractions by intravenous inoculation into sheep, protein determination, electronmicroscopy and enzyme-linked immunosorbent assay. The entire purification procedure could be completed in 4-5 hours using only either infected sheep tissue or nymphae as starting material.     

鸡球虫病与坏死性肠炎的关系

坏死性肠炎（NecroticE nteritis,NE）又称肠毒血症,是由产气荚膜梭菌（Clostridium perfringens）所引起的家禽细菌性肠炎。球虫病（coccidiosis）也是导致家禽业经济损失非常严重的常见疾病。由于球虫抗药性和药物残留的问题,在球虫病控制中免疫预防取代抗球虫药已成为趋势,二者常相伴或相继发生。但球虫病活卵囊疫苗的应用是否增加坏死性肠炎的发生一直受到广泛关注。本文综述了坏死性肠炎发生的主要原因及与球虫病的关系、以及抗球虫药物、球虫病活卵囊疫苗对坏死性肠炎的关系等。     

线粒体与种子老化的关系

种子作为最基本的生产资料,其活力高低直接关系到农业生产的成败。关于种子老化机理的研究是种子科学研究的热点和难点。线粒体是真核生物细胞内重要的细胞器,是细胞能量合成和物质代谢的中心,也是活性氧产生的主要位点,且普遍认为,活性氧是导致种子老化的主要因素。种子老化过程中线粒体的典型结构逐渐被破坏,呼吸速率和氧化磷酸化效率降低,抗氧化功能发生改变,因此,本文主要概述种子的老化与线粒体结构、呼吸作用、抗氧化系统变化的关系,并阐述线粒体与细胞程序性死亡关系的研究进展,系统分析种子老化与线粒体变化研究中存在的问题及未来发展趋势,以期为研究种子老化的线粒体作用机理提供理论基础。     

谷氨酰胺与蛋白质降解的关系

文中综述了谷氨酰胺(Glutamine,Gln)在抑制蛋白质降解代谢中的作用。谷氨酰胺可以通过抑制蛋白质降解系统各组分的形成、前炎症因子的释放、支链氨基酸的释放和诱导热休克蛋白的产生等方式来抑制蛋白质的降解。     

Autoimmune haemolysis in the dog: relationship between anaemia and the levels of red blood cell bound immunoglobulins and complement measured by an enzyme-linked antiglobulin test.

A direct enzyme-linked antiglobulin test (DELAT) was used to measure the levels of red blood cell (RBC) bound IgG, IgM, IgA and C3 in dogs with autoimmune haemolytic anaemia (AIHA). At presentation, one or more DELAT parameters was raised in each AIHA case, and the RBC were typically coated with immunoglobulin of more than one class, together with C3. There was no relationship between the levels of RBC-bound IgG, IgM or IgA and the severity of the anaemia, although a significant negative correlation (rs = -0.66, P < 0.02) was found between bound C3 and blood haemoglobin concentration. These results indicate that the level of sensitisation of erythrocytes with IgG alone is not a reliable predictor of the severity of haemolysis in different cases, and that the pathogenesis of AIHA can be complex, involving multiple immunoglobulin classes and complement in the destruction of RBC. A significant relationship (rs = 0.63, P < 0.02) was found between serum IgG concentration and haemoglobin levels, and it is suggested that this may be due to free IgG inhibiting the interaction of IgG-sensitised RBC with macrophages. Serial measurements from individual AIHA cases during treatment revealed that the levels of RBC-bound immunoglobulins fell simultaneously with improvements in anaemia. In one dog, a relapse was associated with increases in bound IgG and IgM. Transient relative reticulocytopenia at presentation was common, but was not related to the severity of the anaemia. However, in other cases there was a persistent failure to increase RBC production, which was associated with slower recovery.