超高效液相色谱法检测猪肉中乙酰甲喹及其主要代谢物

建立了猪肉中乙酰甲喹及其4种主要代谢物的超高效液相色谱检测方法。试样用二氯甲烷/正己烷混合溶液、超纯水、50mL/L三氯乙酸溶液提取3次,经有机溶剂提取完之后,在氮气下吹干,残渣以300mL/L甲醇水溶液溶解,之后和水相提取液合并,经Strata-X固相萃取小柱净化,用超高效液相色谱法检测猪肉中乙酰甲喹及其4种主要代谢物。选择甲醇-0.2 mL/L甲酸水溶液为流动相,梯度洗脱,流速为0.5mL/min,在241nm波长处检测。该方法检测的乙酰甲喹及其4种代谢物均在0.05μg/g～10μg/g范围内线性良好,相关系数均大于0.999;乙酰甲喹、M1、M2、M5和M10在0.1、1、10μg/g三水平加标回收率分别为80.5%～91.3%、79.3%～88.3%、86.1%～98.3%、77.9%～88.4%和82.9%～94.2%;批间变异系数分别为9.3%～9.6%、5.4%～8.6%、7.3%～9.2%、5.3%～8.3%和6.4%～8.9%。乙酰甲喹及其4种代谢物在猪肉中的检测限均为0.01μg/g,定量限均为0.04μg/g。本研究所建立的方法灵敏、准确、高效,可用于猪肉中乙酰甲喹及其主要代谢产物残留分析。     

乙酰甲喹主要代谢物的合成及体外抗菌活性检测

乙酰甲喹在动物体内被代谢为多种代谢物,其中乙酰甲喹侧链乙酰基加氢还原代谢物(M1),脱一氧M1(M2)、脱二氧M1(M3)为乙酰甲喹主要代谢物。以乙酰甲喹为原料通过Na2S2O4或NaBH4还原合成了此3种代谢物,并用质谱及核磁对合成的代谢物结构进行鉴定,然后对3种代谢物的体外抗菌活性进行测定。根据质谱及核磁结果分析,化学合成的3种化合物结构与代谢物(M1、M2、M3)结构一致,表明正确合成了此3种代谢物;体外抗菌活性研究表明,代谢物M1对大肠杆菌、沙门氏菌及金黄色葡萄球菌的最小抑菌浓度分别为32、128和128μg/mL,与乙酰甲喹相比,抑菌活性明显下降;M2、M3对此3种细菌的抑菌效果不及M1。     

乙酰甲喹在斑马鱼中的代谢研究

为了阐明乙酰甲喹在水产动物中的代谢过程,本试验采用超高效液相色谱串联四级杆/飞行时间质谱(UPLC-Q/TOF-MS)技术及代谢软件MetabolynxXS自动分析采集功能,研究其在斑马鱼中的主要代谢产物。斑马鱼经药浴摄入乙酰甲喹后,分别采用乙酸乙酯和乙腈提取组织中的乙酰甲喹及代谢物,过0.22μm滤膜后经UPLC-Q/TOF-MS分析,通过比较试验组和对照组的色谱图新增色谱峰,确定代谢产物的数量;通过比较乙酰甲喹标准品及代谢产物的精准MS/MS质谱图,确定代谢产物的化学结构,并推测其可能的代谢途径。结果显示,乙酰甲喹在斑马鱼中的代谢产物较少,主要是脱氧代谢物,包括单脱氧代谢物N1-脱氧乙酰甲喹(1-DMEQ)、N4-脱氧乙酰甲喹(4-DMEQ)及双脱氧代谢物N1,N4-双脱氧乙酰甲喹(1,4-BDMEQ),代谢途径主要为N→O基团还原。残留消除规律研究发现,乙酰甲喹消除较快,4h降至初始浓度一半以下,并呈现逐渐降低的趋势;其3种代谢产物浓度均呈现先增高后降低的趋势,其中2种单脱氧代谢物在给药后2h浓度达到最高,8h降至最高浓度一半以下,双脱氧代谢物在给药后4h药物浓度达到最高,12h降至最高浓度一半以下,结果表明,乙酰甲喹在斑马鱼中代谢消除速率较快。上述研究结果可为乙酰甲喹在其他水产食品动物中的代谢研究提供参考,并为水产动物源性食品安全的监控及药代动力学研究提供技术支持。     

乙酰甲喹在斑马鱼中的代谢研究

为了阐明乙酰甲喹在水产动物中的代谢过程,本试验采用超高效液相色谱串联四级杆/飞行时间质谱（UPLC-Q/TOF-MS）技术及代谢软件Metabolynx^XS自动分析采集功能,研究其在斑马鱼中的主要代谢产物。斑马鱼经药浴摄入乙酰甲喹后,分别采用乙酸乙酯和乙腈提取组织中的乙酰甲喹及代谢物,过0.22 μm滤膜后经UPLC-Q/TOF-MS分析,通过比较试验组和对照组的色谱图新增色谱峰,确定代谢产物的数量;通过比较乙酰甲喹标准品及代谢产物的精准MS/MS质谱图,确定代谢产物的化学结构,并推测其可能的代谢途径。结果显示,乙酰甲喹在斑马鱼中的代谢产物较少,主要是脱氧代谢物,包括单脱氧代谢物N1-脱氧乙酰甲喹（1-DMEQ）、N4-脱氧乙酰甲喹（4-DMEQ）及双脱氧代谢物N1,N4-双脱氧乙酰甲喹（1,4-BDMEQ）,代谢途径主要为N→O基团还原。残留消除规律研究发现,乙酰甲喹消除较快,4 h降至初始浓度一半以下,并呈现逐渐降低的趋势;其3种代谢产物浓度均呈现先增高后降低的趋势,其中2种单脱氧代谢物在给药后2 h浓度达到最高,8 h降至最高浓度一半以下,双脱氧代谢物在给药后4 h药物浓度达到最高,12 h降至最高浓度一半以下,结果表明,乙酰甲喹在斑马鱼中代谢消除速率较快。上述研究结果可为乙酰甲喹在其他水产食品动物中的代谢研究提供参考,并为水产动物源性食品安全的监控及药代动力学研究提供技术支持。     

乙酰甲喹及其主要代谢物在鸡体内的残留消除规律研究

建立了高效液相色谱串联质谱（HPLC—MS／MS）法用于乙酰甲喹及其6种主要代谢物的检测。将65只健康白羽鸡分为两组,10只为空白对照组,其余为试验组。试验组施以20mg／kgb．w．灌胃乙酰甲喹悬浊液,1d2次,连续3d。在给药结束后2、4、6、12、16、24、30、36、48、72、120h分别宰杀5只鸡,采集血液和可食性组织（肌肉、肝脏、肾脏和皮脂）样品。结果表明：乙酰甲喹原药在组织和血浆中迅速消除;乙酰甲喹的代谢物广泛存在于鸡的可食性组织和血浆中;代谢物的残留消除过程较为复杂,代谢物在肌肉和肝脏中残留量较多,在皮脂中残留时间最长。研究结果将有助干榍示7．酷甲喹存鸡体内的砖留消除期,律．     

五种兽药中非法添加喹乙醇和乙酰甲喹的HPLC-PDA检测方法的建立

建立了高效液相色谱法测定五种制剂中非法添加喹乙醇与乙酰甲喹的方法。以十八烷基键合硅胶为填充剂,乙腈-0.01mol/L磷酸二氢钾(pH 6.0)为流动相,二极管阵列检测器进行全波长(200～400nm)扫描,检测波长为260nm,并采用峰纯度检查和光谱相似度检查辅助对照品比对方法,对非法添加药物进行确证。结果表明,该色谱条件下喹乙醇、乙酰甲喹与其他物质峰分离良好。喹乙醇、乙酰甲喹在0.5～200μg/mL浓度范围内线性良好,回收率在91.1%～105.7%之间,RSD≤3.1%,喹乙醇、乙酰甲喹的检测限分别为1.0mg/g、2.5 mg/g。     

乙酰甲喹在鸡体内代谢是否产生MQCA的研究

为检测乙酰甲喹在鸡体内是否包含代谢物3-甲基-喹噁啉-2-羧酸,本文以黄羽肉鸡为研究对象,应用3种乙酰甲喹药粉测定MQCA,结果表明:将乙酰甲喹(痢菌净)药粉按梯度饲喂黄羽肉鸡,经24h代谢,其代谢物中包含MQCA,且含量与给药量呈正相关。因此,在养殖生产过程中,使用乙酰甲喹(痢菌净)则直接干扰判定产品中MQCA含量。     

HPLC-PDA法测定兽药中非法添加的喹乙醇、乙酰甲喹检查方法

建立兽药中非法添加喹乙醇、乙酰甲喹的通用检查方法。以十八烷基键合硅胶为填充剂,0.01 mol/L磷酸二氢钾溶液-乙腈为流动相,梯度洗脱,流速为1.0 mL/min,波长扫描范围为200~400 nm,柱温30℃,采用峰纯度检查和光谱相似度检查辅助对照品比对方法,对非法添加药物进行确证。结果显示,喹乙醇、乙酰甲喹与其他物质峰分离良好;喹乙醇和乙酰甲喹在12种兽药中的平均回收率分别为96.6%~101.4%和98.0%~101.3%,RSD均小于1.4%;喹乙醇和乙酰甲喹的检测限均为1.0 g/kg(L)。该检查方法简便、准确、可靠,可用于检查兽药中非法添加的喹乙醇和乙酰甲喹。     

HPLC-DAD法检测三种兽用中药注射液中非法添加喹乙醇和乙酰甲喹方法研究

建立HPLC-DAD法测定3种兽用中药注射液中非法添加喹乙醇和乙酰甲喹的方法。以十八烷基键合硅胶为填充剂、乙腈-水(13∶87)为流动相,用二极管阵列检测器进行全波长(200-400 nm)扫描,检测波长为258 nm,并采用峰纯度检查和光谱相似度检查辅助对照品比对方法对非法添加药物进行确证。结果表明,该色谱条件下喹乙醇、乙酰甲喹与其他物质峰分离良好;喹乙醇、乙酰甲喹在0.5-200μg/mL浓度范围内线性良好,回收率为93.2%~109.9%,RSD≤2.8%,喹乙醇、乙酰甲喹的检测限分别为60μg/mL和100μg/mL。本方法简便快捷、准确度和灵敏度高,能满足非法添加物检测的有关法规和要求。     

二甲硝咪唑在鸡蛋中的残留研究

本文建立了高效液相色谱法(HPLC)测定鸡蛋中二甲硝咪唑(DMZ)残留水平的方法.产蛋鸡内服50 mg/kgbw和200 mg/kgbw、肌注50 mg/kgbw二甲硝咪唑,连用5 d.测定了用药期间及停药后蛋清及蛋黄中DMZ及其羟基代谢物(DMZOH)的含量,方法检测限为0.01μg/g.鸡蛋中DMZ及其DMZOH的含量在休药6～7 d时低于检测水平.排泄到蛋黄中的二甲硝咪唑及其羟基代谢物约占鸡蛋中残留总量的56%,蛋清约占44%.     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.