Alternative matrices for cortisol measurement in fish

Plasma cortisol is the most commonly used indicator of stress in fish but, as the blood sampling procedure itself can be a source of stress, it would be helpful to measure cortisol using less invasive matrices. It is also necessary to find alternative matrices as stress indicators in dead fish in which blood sampling is impossible. In the present study, we investigated transport stress in three aquaculture species, European sea bass (Dicentrarchus labrax L.), common carp (Cyprinus carpio L.) and rainbow trout (Oncorhynchus mykiss Walbaum), by cortisol determination (radioimmunoassay) in plasma and other matrices (skin mucus, gut content, lateral muscle and caudal fin). Cortisol significantly increased after transport in all species and matrices, except in the sea bass gut content, where it remained unchanged. The three species responded to transport stress by producing different cortisol levels. In conclusion, the significant correlation found between plasma cortisol and most of the other matrices opens up the possibility of using them to evaluate stress in fish: mucus sampling is a less invasive method than blood sampling, and in addition to muscle and fin sampling, it can be used in postmortem fish.     

双峰驼妊娠早期外周血浆中孕酮和雌二醇含量的变化及妊娠诊断

本试验用放射免疫分析测定了妊娠早期母驼外周血浆中孕酮、17β—雌二醇的含量,并根据本试验的资料对应用血浆孕酮浓度进行早期妊娠诊断的方法作了分析.结果表明,母驼妊娠早期孕酮水平在配种后第4天开始升高,怀孕头一个月内的峰值为10.59±8.43ng/ml;配种当天17β—雌二醇的水平为12.11±4.44pg/ml,第2天降为8.39±8.92 pg/ml(n=8),但第4天又回升到配种当天的水平,这种现象在其它动物少见。根据配种后第16天的血浆孕酮水平进行妊娠诊断,检出妊娠的准确率达100%。判定标准为1.0ng/ml,即≤1.0ng/ml 者为未孕。>1.0ng/ml 者为怀孕。     

双峰驼促卵泡素放射免疫测定方法的建立

本试验以羊—羊FSH放射免疫分析方法为依据,建立了测定双峰驼外周血浆中FSH的异源性放射免疫分析方法,通过一系列实验表明,在目前尚难建立驼FSH同源性放射免疫分析方法的情况下,该方法是研究双峰驼生殖内分泌学的可靠手段之一。本研究还用此方法测定了肌肉注射精清诱导排卵前后母驼外周血浆中FSH的变化。     

放射免疫测定昆明犬血清T3,T4水平研究初报

利用放射免疫法对36只昆明犬血清三碘甲状腺素(T_3)、四磺甲状腺素(T_4)水平进行了初步研究。测定结果:68日龄幼犬(n=8)的T_3为0.359±0.188 ng/ml血清,T_4为56.56±6.1 ng/ml血清;1～2岁的成年犬(n=28)T_3为0.206±01.09 ng/ml血清,T_4为13.47±4.21 ng/ml血清。该结果表明:昆明犬T_4含量明显高于T_3(P<0.01)。68日龄的幼犬T_3、T_4水平明显高于1～2岁成年犬(P<0.01)。还观察到个别(4~#、6~#)甲状腺素含量明显低于均值(P<0.01),犬体高、体重也低于同年龄犬。     

畜产品中氯霉素的放射免疫测定

本文将氯霉素与牛血清白蛋白连接成复合物,制得特异性强、亲和力高的兔抗氯霉素抗血清,建立氯霉素的放射免疫测定法。其最小检测量为20pg/管,可测范围为50～3200pg,回收率为95.5％±8.7％,批内和批间变异系数分别为4.1％和8.9％。样品制备简单,整个测定可在10h内完成。     

Characterization of the LH peak after short and long fixed‐time artificial insemination protocols in sheep raised in the tropics

The aim of this study was to evaluate the peak in luteinizing hormone (LH) and the pregnancy rate of sheep (Texel × Santa Inês) in the tropics using short‐ (6 days) and long‐term (12 days) progesterone protocols followed by artificial insemination (AI) both in and out of the breeding season. Experiment 1 was conducted within (IN) the breeding season (autumn, n = 36), and experiment 2 was conducted outside (OUT) of the breeding season (spring, n = 43). In each experiment, the sheep were divided into two groups (6 or 12 days) according to the duration of treatment with a single‐use progesterone release vaginal device (CIDR^®, Pfizer, São Paulo, SP, Brazil), and blood samples were collected from 10 animals per group every 4 hr to measure the LH and progesterone concentrations. In the spring, the characteristics of the LH peak did not differ between groups; but in the autumn, there were differences between groups at the beginning (G‐6 IN: 36.44 ± 5.46 hr; G‐12 IN: 26.57 ± 4.99 hr) and end of the LH peak (G‐6 IN: 46.22 ± 7.51 hr; G‐12 IN: 34.86 ± 8.86 hr). The results showed alterations in the LH peak during the breeding season only in the sheep undergoing the short‐term protocol.     

Tissue distribution of dexamethasone in canine ocular compartments following topical application of dexamethasone-21-isonicotinate and oxytetracycline HCl

Objective  To study the dexamethasone (DXM) concentration at different time points in various compartments of the canine eye following topical application of DXM-21-isonicotinate and oxytetracycline hydrochloride
Animals studied  Thirty dogs to be euthanized for reasons not related to this study were selected and their ocular health status evaluated. Selected animals were treated with DXM-oxytetracycline ointment and euthanized after 6, 11 or 16 h.
Procedure  The concentration of DXM was determined in the following compartments of the eye: third eyelid, cornea, aqueous humor, iris, lens, vitreous body and choroid/retina. The DXM concentration in the eye was measured by radioimmunoassay. The applied amount of DXM was 0.04 mg in 0.2 mL ointment. Dogs were treated once with Corti Biciron^® eye ointment (DXM-21-isonicotinate and oxytetracycline hydrochloride, S & K Pharma, Perl, Germany) and were euthanized 6, 11 and 16 h after treatment.
Results  At 6 h following topical application the mean DXM concentration was highest in the anterior structures of the eye (third eyelid: 18 ng/g, cornea: 36 ng/g). The concentration in the posterior structures was below detection level. A decreased DXM concentration in the anterior structures was measured 11 and 16 h after treatment.
Conclusion  It could be demonstrated that therapeutically relevant concentrations of DXM after a single topical administration are only achieved in anterior structures of the eye. A dosing interval of 6–11 h is recommended to achieve therapeutic drug concentration in those structures. The posterior structures of the eye are not reached by topical administration.     

Preparation of protein-steroid conjugates and antisera against oestradiol-17

A conjugate of oestradiol-17β and bovine serum albumin (BSA) has been prepared by the mixed anhydride method. The conjugate was characterized by u.v.-analyses and immunoelectrophoresis, and the number of moles of oestradiol-17β per mole of BSA was found to be 25. The conjugate was used for immunization of two sheep and one rabbit in order to elict antisera against oestradiol-17β. Antibodies could be detected in all three animals after 5–16 weeks depending on the route of immunization. The antiserum from one sheep could be used in a radioimmunoassay system for oestradiol-17β in a dilution of 1:5000 and was found to cross-react with oestrone and oestradiol-17α to a lesser extent than another antiserum against oestradiol-17β.     

Serum bile acids: reference values in healthy dogs and comparison of two kit methods

Serum bile acid (SBA) reference intervals were established by use of a radioimmunoassay method for fasting dogs to be 0.2 to 4.3 micro mol/L (n = 60) and for 2 hour postprandial samples to be 0.6 to 24.2 micro mol/L (n = 37). The SBA reference intervals estimated using an enzymatic method were 0 to 8.6 micro mol/L for fasting (n = 26) and 0 to 29.8 micro mol/L for 2 hour postprandial samples (n = 36). The correlation between the two methods including samples from healthy dogs and clinical cases is good (n = 128, r = 0.82, p < 0.0001). The radioimmunoassay method is linear to 50 micro mol/L and the enzymatic method is linear to 100 micro mol/L, thus both methods require serum dilutions to be made in many cases of primary liver disease. The enzymatic method is less expensive and more convenient for use in a clinical laboratory but requires a greater sample volume (400 micro I) than the RIA method (50 micro I). Both methods have adequate precision and accuracy to be useful as diagnostic tests of liver function in dogs.     

Evaluation of a radioimmunoassay for type III procollagen peptide in the dog

Type III procollagen peptide (P-3-P) is a serum marker for hepatic fibrosis in humans. The utility of a commercially available radioimmunoassay for P-3-P was evaluated in the dog. The specificity of the assay was assessed by polyacrylamide gel electrophoresis (PAGE) of canine serum and purified bovine P-3-P, followed by Western immunoblotting with rabbit aniti-P-3-P serum. The sensitivity was assessed by performing the radioimmunoassay on dilutions of sera from 22 dogs. Polyacrylamide gel electrophoresis of purified bovine P-3-P and sera from two dogs suspected of having elevated P-3-P concentrations revealed no homologous bands of staining. Western immunoblotting showed marked cross-reactivity of the high antisera concentrations with several components of the serum proteins, but none corresponding to the purified P-3-P. All tested sera from dogs had minimal competitive binding with radiolabeled P-3-P in the radioimmunoassay. Dilution curves of dog sera did not parallel either the standard curve or the dilution curve of a known test human serum. There were no statistically different P-3-P concentrations in any of the groups of dogs studied. It was concluded that currently available radioimmunoassay kits for the measurement of P-3-P in the human are not applicable in the dog. Seemingly, the structure or metabolism of canine P-3-P may vary significantly from that of the bovine or human, limiting the sensitivity and specificity of this assay in the dog.