Residues of drugs in eggs after medication of laying hens for eight days.

Drug residues in blood plasma, egg-white and -yolk have been measured for 3 weeks after 8 days of continuous treatment with sulphanilamide, sulphadimidine, sulphaquinoxaline and pyrimethamine. The results are discussed with reference to physiological data concerning eggwhite and -yolk formation. From this, it is concluded that a withdrawal period of at least 10 days after the disappearance of drug in blood plasma is necessary to avoid residues of drugs in eggs from treated hens.     

高效液相色谱法检测牛乳中的磺胺类药残留量

为建立HPLC法测定牛奶中磺胺类药残留量的方法。样品经乙腈处理沉淀蛋白质后取上清液浓缩,以乙腈-水(体积比为1∶1)为流动相进行高效液相色谱分析。结果表明4种磺胺类药分离效果良好,平均回收率范围81.6%～95.8%,相对标准偏差为1.5%～4.2%,最低检出限达1.0～2.0ng/mL。可见该检测法具有灵敏、准确、精密、无杂质干扰等优点。     

高效液相色谱—紫外法对13种磺胺类药物的同步检测

本研究旨在建立同步测定多种磺胺类药物残留的高效液相色谱—紫外法。通过对磺胺嘧啶(SD)、磺胺醋酰(SA)、磺胺喹噁啉(SQ)、磺胺氯丙嗪(SUL)、磺胺间甲氧嘧啶(SMM)、磺胺对甲氧嘧啶(SMD)、磺胺二甲氧嘧啶(SDM')、磺胺异噁唑(SIZ)、磺胺噻唑(ST)、磺胺噻唑钠(ST-Na)、酞磺胺噻唑(PST)、磺胺甲噁唑(SMZ)、琥珀酰磺胺噻唑(SST)等13种磺胺类药物进行紫外波长扫描分析,选择色谱检测的波长为270 nm。由于磺胺类药物的酸碱度不同及结构差异,在经过多种组合比较后,选择乙腈和乙酸水溶液作为流动相进行梯度洗脱,建立的条件可将这些药物分开,13种药物可以分离得到10个色谱峰,ST-Na、PST和ST 3种成分重叠,SDM'和SMZ重叠。用乙腈—氯仿作样品提取并抽提,杂质干扰较少,回收率80%以上,分析用时相对较短。     

Substitution of dietary calcium chloride for calcium carbonate reduces urinary ph and urinary phosphorus excretion in adult cats

Summary

In a 4×4‐vvk cross‐over study, eight adult cats were given four moist diets containing identical amounts of calcium (13.9 mmol/MJ) but with different ratios of calcium carbonate to calcium chloride, the calcium salts providing half of the total dietary calcium. Increasing amounts of calcium chloride were substituted for equimolar amounts of calcium carbonate. Higher intakes of calcium chloride caused significantly lower pH values in postprandial and 24‐h urine samples. The urinary excretion of ammonium and titratable acid rose with increasing calcium chloride intake. The urinary concentrations of calcium and magnesium were not affected by the type of calcium salt, but the urinary excretion and concentration of phosphorus were significantly depressed when the amount of calcium chloride in the diet was increased. The results are discussed in the context of dietary prevention of and therapy for struvite urolithiasis in cats.     

QuEChERS-UPLC-MS/MS快速测定鸡肝中七种磺胺类药物残留

建立了一种通过QuEChERS方法和超高效液相色谱-串联质谱法快速测定鸡肝中七种磺胺类药物残留量的方法。样品以磺胺二甲氧嘧啶-D6为内标,经DisQuE萃取管提取,DisQuE净化管净化,浓缩后经超高效液相色谱分离,串联质谱测定。结果表明在12.5～125 ng/mL范围内各磺胺类药物均呈良好的线性关系,高中低浓度回收率在70%～115%,精密度小于15%。该方法快速、简便,适于鸡肝中七种磺胺类药物的批量测定。     

Prevalence of enterotoxigenic staphylococci in nose, throat and skin lesions in meat-workers

The frequency of enterotoxigenic coagulase-positive and coagulase-negative staphylococci in nose and throat and in hand lesions was investigated in 86 meat cutters and dressers. Enterotoxin-producing staphylococci were demonstrated in nasal swabs from 22% of clinically well workers and from 42% of a group with mild coryza. The corresponding rates in throat swabs were 6 and 12%. Four of 16 superficial lesions of the hand harbored enterotoxigenic staphylococci. The implications for contamination of food and outbreaks of staphylococcal food poisoning are discussed.     

Aspects of pharmacology in the neonatal foal

Other therapeutic agents used in foals for specific diseases are discussed elsewhere. The marked effect of species, age, and degree of maturity on drug metabolism in the neonate reinforces the danger of interspecies extrapolation of pharmacology, the need for information specific for the foal, and the necessity for monitoring drug levels in the individual. Suggested antimicrobial doses are listed in Tables 3, 4, and 6. Recommended doses of anticonvulsants and sedatives are listed in Table 8 and in the article "Intensive Care of the Neonatal Foal." The following are recommendations for drug therapy in the neonate: Avoid unnecessary administration of drug to the dam at parturition because of possible placental transfer of the drug with subsequent effects on the neonate. If possible, avoid unnecessary drug therapy in foals under 30 days of age. Select a drug that undergoes minimal biotransformation (hepatic metabolism) and is not highly protein bound. Owing to probable immunodeficiency in the neonate, broad-spectrum, bactericidal drugs are preferred for treatment of life-threatening infections. Every attempt should be made to identify the etiologic agent so that drug therapy can be based on cultures and sensitivity test results to maximize the benefit-risk ratio. Parenteral (intramuscular or intravenous) drug administration is preferable to oral. Avoid drugs that are known oxidants, which may produce hemolysis or methemoglobinemia. In general, the same or a slightly higher initial dose should be employed in the neonate, but it should be given less frequently than in the adult if it has a high potential to cause toxicity. When possible, individual monitoring of serum levels of potentially toxic drugs should be employed in premature and newborn foals unless specific drug pharmacokinetics are known for that age group.     

Dietary intake estimates as a means to the harmonization of maximum residue levels for veterinary drugs. I. Concept

The harmonization of standards and procedures for establishing tolerances or maximum residue levels (MRLs) for veterinary drug residues in edible animal products is a major goal of the international veterinary drug community. Such harmonization would contribute to easing trade barriers. This paper proposes use of the toxicologically determined acceptable daily intake (ADI) for the drug as the safety standard for reaching conclusions on the acceptability of residues in meat for human consumption. Specifically, the 'equivalence' of different MRLs for the same veterinary drug would be determined by considering whether they are likely to result in dietary residues that exceed another country's ADI for the drug. Two methods of estimating dietary intake are described, and estimates are made for the veterinary drugs albendazole and ivermectin. Based on these estimates, the US and JECFA MRLs for each drug would be considered 'equivalent' for trade purposes.     

Use of the food animal residue avoidance databank

In its extra-label drug use policy, the FDA states, as one of the criteria for permitting extra-label drug use, that a significantly extended time period be assigned for drug withdrawal prior to marketing meat, milk or eggs. The phrase "significantly extended time period" is taken to mean, at minimum, the amount of time necessary for any drug residues to deplete to subtolerance levels; however, determination of this period is left to the discretion of the veterinarian responsible for the extra-label drug use. The extended period will vary for each drug, dose, species, and route of administration. Therefore, it is unrealistic to assume that the practitioner can make a rational determination of extended drug withdrawal times without more information than is available through textbooks and professional journals. FARAD was specifically designed to provide veterinarians with the information required to determine extended withdrawal times, and thus prevent residues when drugs are used in an extra-label manner. FARAD can provide valuable residue avoidance assistance to veterinarians when drugs are administered in an extra-label manner, but it is not the answer to the national drug residue problem. Most residues result from failure to observe label-recommended withdrawal times, whereas less than 20% are thought to result from extra-label drug use. A substantial armamentarium of approved drugs is available to the veterinarian to treat most diseases in beef cattle, swine, and broiler chickens; thus, extra-label drug use in these species is unnecessary under most conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Drug hypersensitivity reactions targeting the skin in dogs and cats

Adverse drug reactions (ADRs) can be dose dependent or idiosyncratic. Most idiosyncratic reactions are believed to be immune-mediated; such drug hypersensitivities and allergies are unpredictable. Cutaneous reactions are the most common presentation of drug allergies. In veterinary medicine it can be difficult to assess the true prevalence of adverse drug reactions, although reports available suggest that they occur quite commonly. There are multiple theories that attempt to explain how drug allergies occur, because the pathogenesis is not yet well understood. These include the (pro)-hapten hypothesis, the Danger Theory, the pi concept, and the viral reactivation theory. Cutaneous drug allergies in veterinary medicine can have a variety of clinical manifestations, ranging from pruritus to often fatal toxic epidermal necrolysis. Diagnosis can be challenging, as the reactions are highly pleomorphic and may be mistaken for other dermatologic diseases. One must rely heavily on history and physical examination to rule out other possibilities. Dechallenge of the drug, histopathology, and other diagnostic tests can help to confirm the diagnosis. New diagnostic tools are beginning to be used, such as antibody or cellular testing, and may be used more in the future. There is much yet to learn about drug allergies, which makes future research vitally important. Treatment of drug allergies involves supportive care, and additional treatments, such as immunosuppressive medications, depend on the manifestation of the disease. Of utmost importance is to avoid the use of the incriminating drug in future treatment of the patient, as subsequent reactions can be worse, and ultimately can prove fatal.     

常见耐药基因多重PCR方法的建立及用于禽致病性大肠杆菌耐药性监测

本研究旨在建立β-内酰胺类、四环素类、氨基苷类、酰胺醇类、磺胺类抗菌药物耐药基因的多重PCR检测方法,用于耐药基因的快速检测。根据GenBank公布的上述5类抗菌药物的耐药基因序列,设计17对特异性引物。通过优化PCR体系和反应程序,建立4组耐药基因（cat+floR+tetB+tetC;dfrA12+sul2+sul1+bla_CTX-M+bal_TEM-1;aac3+aph3+aadA1+strB;tetA+cmlA+strA+sul3）的多重PCR反应体系。然后,检测多重PCR方法的特异性和敏感性。利用建立的多重PCR方法检测42株禽致病性大肠杆菌的耐药基因,同时,检测其耐药性,比较分析耐药基因和耐药表型之间的相关性。结果显示,建立的4组多重PCR体系可有效扩增出17个耐药基因片段,测序结果表明特异性较好。敏感性结果表明,4组多重PCR体系的菌液敏感性分别为10³、10⁴、10⁴和10⁵CFU。禽致病性大肠杆菌分离株的耐药基因多重PCR和单重PCR检测结果一致,其携带的耐药基因和耐药表型的符合率为92.86%。本研究建立的耐药基因多重PCR方法能简便、快速地检测常见的耐药基因,可用于耐药基因的传播、流行调查。     

Development and Application of Multiplex PCR Method for the Drug Resistance Genes Detection in Avian Pathogenic Escherichia coli

To detect the drug resistance genes, the multiplex PCR method for drug resistance genes of β-lactams, tetracyclines, aminoglycosides, amphenicols, and sulfonamides were developed. Based on the sequences of drug resistance genes from GenBank, 17 pairs of specific primers were designed. Then, 4 multiple PCR assays were established through the optimization of PCR reaction conditions and primers concentrations (cat+floR+tetB+tetC; dfrA12+sul2+sul1+bla_CTX-M+bal_TEM-1; aac3+aph3+aadA1+strB; tetA+cmlA+strA+sul3). The sensitivity and specificity of these assays were determined. The multiplex PCR assays were used to detect the drug resistance genes of 42 avian pathogenic Escherichia coli (APEC). The drug sensitivity of these APEC strains were also determined, which were compared to the distributions of drug resistance genes in these strains. The results showed that the 17 drug resistance genes were effectively and specifically amplified in these 4 optimized multiplex PCR assays. The detection limits of the 4 multiplex PCR were 10³, 10⁴, 10⁴ and 10⁵CFU of bacteria, respectively. The established multiplex PCR assays are specific and rapid for the detection of drug resistance genes in APEC strains, which showed 92.86% coincident with the drug resistance for these strains. The developed 4 multiplex PCR are simple and rapid assays for drug resistance genes detection, which can be used for the epidemiologic study for drug resistance genes.     

Advances in Exotic Mammal Clinical Therapeutics

It is imperative that the veterinarian treating exotic companion mammals stay abreast of the latest developments relating to medications and drug delivery approaches for safety and efficacy. Sustained-release formulations of commonly used drugs, as well as newer routes for administration of therapeutic agents, allow the veterinarian treating exotic companion mammals to reduce the stress associated with drug administration. Interactions can occur between vehicle and drugs when formulations are compounded; therefore, research studies are warranted regarding potential problems associated with these formulations. However, newer studies have been published that provide the basis for exploring the use of different vehicles, frequency of dosing, and drug delivery techniques for various classes of drugs in exotic mammals. The goals of this review are to not only evaluate new medications or uses for medications in companion exotic mammal patients but also review new methods of drug delivery that might be useful to the veterinarian who treats these animals.     

动物源性食品中多种兽药残留种类及检测方法

动物源食品中多种兽药残留主要是动物在生长和加工中额外添加。该种残留现象具有水平低、种类多、机制效应复杂的特点。针对该种动物制品在进行兽药残留检测中应综合运用新技术新方。目前在动物源食品中多种兽药残留检测中常用的技术为高效液相色谱质谱联合使用技术,该项技术具有检测灵敏度高,数据获取精准的特点,能对多种兽药残留情况进行定性定量的分析,在动物源食品多种兽药残留检测过程中应用较为广泛。该文主要论述动物源食品中多种兽药残留的种类及兽药残留检测技术。     

Volumes of distribution

Volumes of distribution are proportionality constants between total amount of drug in the body and plasma concentrations. As snapshot plasma drug concentrations may be measured in different conditions (at equilibrium, under pseudo-equilibrium condition,...), several volumes of distribution have been defined. The two most relevant are the volume of distribution at equilibrium (V(ss)), and the volume of distribution during pseudo-equilibrium (V(area)). Volumes of distribution are used to compute a loading dose (V(ss)) or the residual amount of drug in the body knowing plasma concentrations (V(area)). Volume of distribution may be interpreted in terms of drug distribution having recourse to physiological models involving drug binding to plasma and tissues. Volumes of distribution should be determined early in drug development programmes and those having a large volume of distribution may be selected to obtain a long terminal half-life even for drugs having a relatively high clearance.     

Renal excretion of N4-acetyl sulphanilamide and N4-acetyl sulphadimidine in goats

The renal excretion of N⁴-acetyl sulphanilamide and N⁴-acetyl sulphadimidine was studied in 19 experiments with 6 goats during continuous intravenous administration of the 2 sulphonamide derivatives. Deacetylation of both compounds takes place to a small extent only. Further it is shown that both sulphonamide derivatives are bound to plasma proteins to a greater extent than sulphanilamide and sulphadimidine. The excretion of the N⁴-acetylated sulphonamides is compared with the renal excretion of creatinine. The non-protein-bound fraction of the 2 N⁴-acetylated sulphonamides is excreted by filtration and active tubular secretion. The renal clearances of the acetyl derivatives are higher than those of the parent compounds.