首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2篇
  免费   3篇
  国内免费   2篇
  2篇
综合类   1篇
畜牧兽医   4篇
  2022年   1篇
  2020年   1篇
  2019年   1篇
  2014年   1篇
  2008年   1篇
  2005年   1篇
  1989年   1篇
排序方式: 共有7条查询结果,搜索用时 0 毫秒
1
1.
A method for the detection of the effects of antibiotics on soil microbial communities was optimised in the present study. We investigated the influence of measurement time and nutrient status on the pollution-induced community tolerance (PICT), using the sulfonamide sulfachloropyridazine (SCP) as model compound. The tolerance development in soil microcosms that were exposed to SCP under different conditions was compared with the background tolerance in SCP-unexposed microcosms. The tolerance of bacterial extracts from the soil microcosms was determined in Biolog® multiwell plates as the SCP sensitivity of a range of physiological processes. The background tolerance was not affected by soil nutrient amendments, but an influence of the inoculum density in the microtiter plates was observed. Still, the variance of the background tolerance was low, which is in favour of the usage of community tolerance measurements for a selective detection of a toxicant impact. In line with the assumptions of the PICT concept, soil amendment with SCP led to an increase in community tolerance. This tolerance development was enhanced upon additional soil amendment with fresh pig slurry, and less by alfalfa meal addition. Tolerance increases were observed after a soil exposure to SCP of only 7 days, possibly because nutrient input facilitates the fast adaptation of the soil microbial community. However, a further increase in exposure time led to variable changes in the observed tolerance. Prolonged tolerance detection in the microtiter plates (11 days) enabled a clearer differentiation between different soil treatments, as it better resolved the EC50 values of processes with a high tolerance to bacteriostatic antimicrobial compounds. For the detection of antibiotic effects on soil microbial communities, it is therefore recommended to use nutrient amendments (possibly fresh pig slurry), to standardize the soil exposure time, and to extend the period of Biolog plate measurement beyond 7 days.  相似文献   
2.

Background

Long‐duration beta‐lactam antibiotics are used for empirical treatment in female dogs with uncomplicated bacterial cystitis. However, women with bacterial cystitis are treated with short‐duration potentiated sulfonamides because longer courses of beta‐lactams result in lower cure and higher recurrence rates.

Hypothesis/Objectives

Short‐duration potentiated sulfonamide treatment is more efficacious than long‐duration beta‐lactam treatment in achieving clinical and microbiological cures in female dogs with uncomplicated bacterial cystitis.

Animals

Thirty‐eight client‐owned female dogs.

Methods

Randomized, double‐blinded, placebo‐controlled clinical trial. Dogs were treated with TMPSMX (15 mg/kg PO q12h for 3 days followed by a placebo capsule PO q12h for 7 days; Group SDS; n = 20) or cephalexin (20 mg/kg PO q12h for 10 days; Group LDBL; n = 18). Dogs were monitored for clinical and microbiological cure during treatment and at short‐ and long‐term follow‐up.

Results

No statistically significant differences were found between treatment groups in clinical cure rates after 3 days of treatment (89% SDS, 94% LDBL; P = 1.00) and 4 days (85% SDS, 72% LDBL; P = .44) or >30 days (50% SDS, 65% LDBL; P = .50) after conclusion of treatment or in microbiological cure rates 4 days (59% SDS, 36% LDBL; P = .44) or >30 days (44% SDS, 20% LDBL; P = .40) after conclusion of treatment.

Conclusions and Clinical Importance

We did not identify a difference in cure rates between short‐duration sulfonamide and long‐duration beta‐lactam treatments in female dogs with uncomplicated cystitis. Long‐term cure rates in both treatment groups were low. In some female dogs, “uncomplicated” bacterial cystitis may be more complicated than previously recognized.  相似文献   
3.
建立了高效液相色谱法测定鸡蛋中6种磺胺药物(磺胺嘧啶、磺胺二甲嘧啶、磺胺甲氧哒嗪、磺胺甲噁唑、磺胺二甲氧嘧啶和磺胺喹噁啉)残留的提取、净化和高效液相色谱分析条件,鸡蛋经乙腈提取、固相萃取净化处理后上机检测,6种磺胺药物浓度在0.01~1.0μg/mL范围内标准曲线的相关系数(R2)为0.9999~1,在0.05~0.15 mg/kg浓度范围内,回收率为74.6%~94.3%.检测限为0.00185~0.00264 mg/kg,定量限低于0.0112 mg/kg.方法已应用于实际样品的测定.  相似文献   
4.
建立的固相萃取-高效液相色谱法具有灵敏度高、检测限低的特点,可同时定量检测奶牛粪污中磺胺嘧啶、磺胺二甲嘧啶、磺胺间甲氧嘧啶、磺胺甲恶唑、磺胺喹噁啉的残留。采用C18色谱柱(500 mm×4.6 nm, 5μm),以0.3%的乙酸-乙腈溶液为流动相,在流速1.0 mL/min、检测波长270 nm、柱温30℃条件下,5种抗生素均能达到基线分离;3倍信噪比下,5种抗生素的检出限均为20μg/kg。在加标浓度50μg/kg条件下,奶牛粪污样品经前处理、MCX固相萃取小柱富集净化后,五种磺胺类抗生素回收率达到75%~80%,相对标准偏差为2.8%~3.9%。此方法检测了某规模化奶牛场粪污中磺胺类抗生素残留,结果显示,磺胺嘧啶的浓度范围在45~50μg/kg,其他抗生素无检出。  相似文献   
5.
本文以重氮偶合比色法(以下称B-M比色法)或高效液相色谱(以下简称HPLC)法,对磺胺药和三甲氧苄胺嘧啶(TMP)在马体内代谢动力学特征进行了分析。其中磺胺二甲基嘧啶(SM_2)和TMP在血浆中的浓度用HPLC法进行测定。SM_2测定的紫外检测器波长为275nm;流动相为甲醇:去离子水(50:50/V:V)并以36%乙酸将pH调至4.0,流速为0.5ml/min;SM_2的滞留时间为8.05分钟,内标物SMM的滞留时间为9.90分钟。TMP的测定使用紫外检测器,检测波长为254nm;流动相为甲醇:双重蒸馏水:磷酸盐缓冲液(pH7.0):36%乙酸(70:30:1:1),流速为0.8ml/min。SD、SMD、SMM和SDM′的血中浓度用B-M比色法测定。血药浓度—时间数据按多室动力学处理,用Sharp PC-1500袖珍计算机计算数据,所得磺胺药和TMP的动力学参数如下:SD、SM_2、SMD、SMM、SDM′及TMP的t_(1/2)β分别为5.41±1.45、12.92±4.17、5.76±1.22、4.45±1.44、14.13±2.15及4.20±1.08(hr.);表观分布容积(Vd)分别为10.34±1.13、7.95±1.77、4.91±0.46、7.79±0.66、5.69±2.19(100ml/kg)及2.24±0.60(L/kg);曲线下面积(AUC)分别为53.42±14.81、245.14±61.35、84.37±12.73、74.78±18.36、169.74±27.13(mg%·hr.)及41.67±10.40(μg·hr./ml);清除率(Cl_B)分别为1.4476=0.5230、0.431  相似文献   
6.
对猪、鸡、牛、羊粪污中同时测定7种磺胺类和8种氟喹诺酮类兽药残留的超高效液相色谱-串联质谱方法进行了研究。样品采用2%氨化乙腈+0.1 mol/L 氢氧化钠溶液(50:50,V/V)提取,提取液浓缩后用磷酸盐缓冲液溶解,HLB 固相萃取小柱净化,浓缩富集后用乙腈:0.1%甲酸水溶液(20:80,V/V)复溶,过0.22 μm微孔滤膜,上机,基质加标液外标法定量。结果显示,猪、鸡、牛、羊粪污中15种兽药浓度在1~100 μg/mL范围内线性关系良好(R2>0.994)。方法的检出限为20.0 μg/kg,定量限为50.0 μg/kg。在50、100、500 μg/kg三个添加浓度下,15种兽药平均回收率为60.5 %~115.5 %,批内RSD为1.2 %~17.6 %,批间RSD为0.2 %~17.6 %。该方法具有较好的准确度、精密度,能快速、高效、方便、准确地测定猪、鸡、牛、羊粪污中15种兽药残留,为进一步调查掌握我国畜禽养殖粪污中的残留兽药种类及残留量,提供强有力的技术支撑。  相似文献   
7.
刘潇雅  徐源洲  贺南南  李辉信  胡锋  徐莉 《土壤》2019,51(6):1129-1136
设计正交试验对红壤中磺胺甲恶唑(sulfamethoxazole, SMZ)的萃取方法进行优化,并结合高效液相色谱,构建了固相萃取-高效液相色谱联合测定法(SPE-HPLC),并将该方法应用于不同抗生素以及不同类型土壤中SMZ的提取测定。结果表明,在以乙腈–磷酸盐缓冲液为提取液、提取液量为10 ml、超声时间为15 min、9 ml甲醇淋洗固相萃取柱(HLB)的条件下,红壤中SMZ的提取效果最优,0.25 mg/kg的SMZ回收率达到85.58%,能够满足环境样品的分析要求。利用该法提取测定红壤中不同抗生素包括3种磺胺类抗生素(磺胺嘧啶、磺胺二甲基嘧啶、磺胺甲基嘧啶)和2种四环素类抗生素(土霉素、盐酸四环素),结果表明,当抗生素浓度为0.25 mg/kg时,磺胺类抗生素(SAs)的回收率范围在67.31%~85.58%,四环素类抗生素(TCs)的回收率范围在20.81%~59.33%。利用该法分别提取测定不同类型土壤中的SMZ回收率,得到潮土中SMZ的回收率最大,达到92.92%,其次为荒漠土、红壤、紫色土,最低的回收率出现在黄棕壤,仅为53.62%。据相关性分析表明,回收率与土壤电导率(EC)、微生物碳氮比(C/N)呈极显著负相关(P0.01),与阳离子交换量(CEC)、有机质(SOM)呈显著负相关(P0.05)  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号