Prevalence of Gastric Ulcerations in Horses with Colic

The goal of this study was to determine the prevalence of gastric ulcers in horses with acute abdominal crisis (colic) and to examine the temporal effect of hospitalization on ulcer development in equine patients treated for colic. In addition, other factors that may be associated with gastric ulceration were also explored. The study design was a prospective original study incorporating 169 horses that presented to the George D. Widener Hospital for examination. One hundred and twelve horses presenting with the chief complaint of colic were included in the study group, and 57 horses that presented for non-colic or nonemergency complaints were evaluated and included as case controls. Gastroscopy was performed on equine patients presenting with the chief complaint of colic or horses presenting for reasons other than colic (control); mucosal changes were scored 0 to 3. Additionally, horses presenting for colic were gastroscopically evaluated twice during a 5-day period. Medical records were reviewed for history, clinical findings, laboratory results, and treatment. Seventy-six of 112 horses presenting with the chief complaint of colic had gastric ulceration compared with 41 of 57 horses in the control group. There was a significant association between age of the patient and chief complaint (ie, colic vs control) and between breed and chief complaint. There was no association between gastric ulcer score and chief complaint (colic vs control). Thirty-eight of the 112 horses presenting with colic deteriorated in ulcer score while hospitalized. Using a Pearson chi-squared test, there was no statistically significant association between gastric ulceration with age, breed, or sex. Horses with gastric ulceration in the colic group had lower packed cell volumes compared with horses presenting with colic without gastric ulcers, and this was statistically significant (P < .001). The high incidence of gastric ulceration in the study and control groups supports the reports of other investigators that gastric ulcers in horses, no matter the presenting complaint, are widespread. There was a significant association between breed and chief complaint (P = .005); however, breed and outcome of gastric ulceration were not related (Thoroughbreds were the least likely breed to present for colic). Although a trend in increasing gastric ulceration was seen in hospitalized colic patients, it was not statistically significant. This suggests that horses that are hospitalized may be at increased risk for developing gastric ulcers because of stress, feed deprivation, and administration of treatment. Thus, horses that present for colic should be gastroscopically evaluated if clinical signs raise the index of suspicion for gastric ulceration.     

芹菜叶斑病病原菌细极链格孢药剂筛选

【目的】研究筛选对芹菜叶斑病(病菌为:细极链格孢Alternaria tenuissima)具有良好防治作用的药剂。【方法】采用菌丝生长速率法和琼脂片法分别用14种杀菌剂对细极链格孢(A.tenuissima)菌丝和孢子萌发做室内毒力测定并进行田间药效试验。【结果】14种杀菌剂中对病原菌菌丝抑制效果最好的分别为3%甲霜恶霉灵、5%香芹酚、10%苯醚甲环唑、其EC₅₀分别为10.8、19.9、26.2 μg/mL;对孢子萌发抑制效果最好的分别为3%甲霜恶霉灵、25%嘧菌酯、43%戊唑醇,其EC₅₀分别为15.7、29.5、38.7 μg/mL。只有3%甲霜恶霉灵具有最佳的防治效果。防效最好的药剂为3%甲霜恶霉灵和5%香芹酚,其防效分别为96.3%和83.9%。【结论】3%甲霜恶霉灵最适用于田间芹菜叶斑病的防治。     

Intensification of arsenic toxicity to paddy rice by hydrogen sulfide and ferrous iron

Abstract

The phytotoxicity of arsenic to paddy rice was examined by the pot culture method using Utsunomiya grey lowland soil which had received nutrient salts including ammonium sulfate with or without additional rice straw powder as a reducing agent.

By treatment with 50 ppm of arsenic and straw, plant growth was retarded from the beginning of culture, and about 6 weeks later, at the middle of July, small reddish black spots emerged near the tips of expanded green leaves. The spots then increased and spread over the whole leaves resulting in bronzing and final dieback in about the mid-August. On treatment with higher concentrations of arsenic and straw, the plants were more severely injured and died through bronzing at earlier stages. All such dead plants were found to have accumulated abnormally high iron in their leaf tissues. On treatment with lower concentrations of arsenic and straw or in the case of higher arsenic without straw, plant growth and grain yield were reduced with the occurrence of partial bronzing or oranging of leaves and the iron content of the plants was somewhat increased.

These results indicate that arsenic may induce ferrous iron toxicity which intensifies the toxicity of arsenic to paddy rice.     

植物对土壤钼污染的响应及其耐钼机制研究进展

钼是植物、动物和微生物必需的微量元素之一,同时也是一种重金属元素。以往对钼的研究主要关注钼缺乏对农作物产量与品质的影响及危害,对钼污染导致的生态风险及应对策略研究较少。本文在分析我国土壤钼污染现状及其生态风险的基础上,综述了钼污染对植物生长发育的影响、钼对植物的毒害阈值及其影响因子,以及植物对钼污染的耐性机制,并展望了未来土壤-植物系统钼污染的研究方向,以期为土壤钼污染的风险管控及修复提供参考。     

灌木幼苗对镉毒害的敏感性差异

为探究灌木幼苗及不同测试终点对镉（Cd）毒害的抗性和敏感性差异,选取了12种常见的灌木植物,通过Cd对灌木幼苗毒害的水培试验,测定不同含量Cd处理［0（对照）、0.5、1.0、2.0、4.0、8.0、16.0、32.0 mg·L^-1］下植物的生长状况（表观毒害症状、株高、地上部鲜重和干重、根系生长状态）,比较不同测试终点稳定性,并运用Burr-Ⅲ模型制作物种敏感性分布图（species sensitivity distributions,SSD）,分析不同灌木幼苗对Cd的敏感性。结果表明,供试植物在Cd含量为1.0~4.0 mg·L^-1时开始出现表观毒害症状;Cd对不同的植物地上部和根系毒害阈值差异较大,地上部干重减少10%（EC₁₀）和50%（EC₅₀）对应的毒性阈值变化范围分别为0.11（海桐）~1.30 mg·L^-1（八角金盘）和2.58（金森女贞）~10.90 mg·L^-1（八角金盘）,差异分别达到了11.8和4.2倍;根分支数对应的EC₁₀和EC₅₀变化范围分别为0.08（金森女贞）~1.27 mg·L^-1（八角金盘）和2.40（金森女贞）~10.30 mg·L^-1（八角金盘）,差异分别达到了15.8和4.3倍;不同测试终点的敏感性从大到小依次为根分枝数>总根长>总根表面积>总根尖数>地上部分干重>株高>地上部分鲜重,说明根系指标对Cd毒性更为敏感;基于地上部干重和根分支数的EC₅₀数据得到的SSD表明,大部分植物的敏感性分布趋于一致,其中金森女贞和海桐对Cd毒害最为敏感,八角金盘为Cd毒害的抗性品种;同时,根据SSD得出保护95%林木品质不受Cd毒害的生态风险阈值HC₅。     

青霉菌毒素的某些毒性机理

用标准和从饲料中提取的青霉素（桔青霉素毒素和青霉酸）对家兔，蟾蜍进行了某些毒性机理的研究，结果表明，青霉菌毒素具有促进胃肠蠕动，增绳子宫收缩和减慢心率的毒性作用。     

有机化工废弃物的土地处理研究

本文对三种供试工业废弃物，经土地处理后表明，发光细菌毒性明显降低，有的废渣处理物毒性已消除；Ａｍｅｓ试验和发光细菌自发暗变种的遗传毒减弱，由阳性下降为阴性，或阳性程度明显减弱。     

杀虫剂对小眼书虱成虫的触杀毒力

采用滤纸药膜法比较了常用12种杀虫剂对小眼书虱Linposcelis paeta Pearman的触杀作用,在药剂的推荐浓度下有机磷类杀虫剂对小眼书虱的急性触杀作用强于其它药剂,同时测定了杀虫松、敌敌畏和凯安保3种药剂对小眼书虱的触杀毒力,其24 h内触杀作用的LC50分别为0.0879 μg/cm2、0.0725和2.2042 μg/cm2.     

6个坚尼草品种比较试验报告

采用玻片浸渍法,进行了8种杀虫剂对海南白沙及东方两地的橡胶六点始叶螨(Eotetranychus sexmaculatus Riley.)♀成螨的室内毒力测定。结果表明：1.8% 阿维菌素对白沙及东方两地的♀成螨毒力均最高,LC50值分别为0.068 9、0.075 1 mg/L;其次为10% 溴虫腈和2.5% 高效氯氟氰菊酯,LC50值分别为15.481 6 、10.153 2 mg/L和431.895 2、350.068 2 mg/L,8种药剂对该螨雌成螨的毒力大小顺序均为阿维菌素、溴虫腈、高效氯氟氰菊酯、毒死蜱、哒螨灵、甲氰菊酯、三唑锡与克螨特。与敏感种群相比,白沙、东方两地六点始叶螨对克螨特、毒死蜱、甲氰菊酯、哒螨灵与三唑锡均已产生较高抗药性。     

调环酸钙安全性初步评价

【目的】评价调环酸钙原药的急性毒性,为安全使用调环酸钙提供毒理学依据。【方法】按照我国现行《农药登记毒理学试验方法》（GB15670-1995）规定的方法,以SD大鼠为对象,采用一次最大剂量法,对调环酸钙原药进行急性经口、经皮毒性试验。【结果】调环酸钙原药对SD大鼠的急性经口半数致死量（LD50）〉5000mg/kg·BW,经皮LD50〉2000mg/kg·BW。【结论】调环酸钙对大鼠的急性经口、经皮毒性均属于低毒性,符合绿色农业生产的要求。