A rapid radioimmunological evaluation of the androstenone content in boar fat

Fat from boars containing androstenone is absorbed to a piece of filter paper. The filter paper is then placed in a tube and a buffer containing antibodies against androstenone is added. Following incubation the filter paper is removed, and by measurement of the residual binding capacity for androstenone in the buffer a relative value for androstenone content in the fat is obtained.The coefficient of correlation between the results obtained by this rapid method and the ordinary radioimmunoassay was −0.95.     

牛奶中四环素类抗生素放射免疫检测方法验证分析

验证了牛奶中四环素类抗生素残留检测的放射免疫方法。该法检测牛奶中四环素、土霉素、金霉素3种四环素类药物的最低浓度可分别达到30、100、50μg/L,RSD(n=6)均小于3.9%。该方法特异性强,与环丙沙星、链霉素、青霉素G、阿莫西林、磺胺嘧啶、磺胺甲基嘧啶、红霉素、螺旋霉素无交叉反应。因此,该法能达到检测牛奶中四环素类抗生素残留的要求。     

Comparison of radioimmunoassay and chemiluminescent assay methods to estimate canine blood cortisol concentrations

Background Non‐radioactive assay methods are widely used in commercial laboratories to measure canine blood cortisol concentrations, despite a paucity of published validity data of these tests compared with the traditional ‘gold standard’ radioimmunoassay. Objectives To compare a commercial chemiluminescence assay with radioimmunoassay for blood cortisol measurement, determine the effect of storage on the radioimmunoassay, and determine the impact of any differences on clinical decisions. Methods The study included 54 client owned dogs undergoing adrenal function testing. Fresh plasma or serum samples (n = 170) were assayed for cortisol using radioimmunoassay (RIA1). Samples (n = 196) were also frozen and stored in batches, and assayed by chemiluminescence and radioimmunoassay (RIA2). Results Overall, there was a strong correlation (r² = 0.967, P < 0.001) between RIA2 and chemiluminescence concentrations without significant difference between means. Strong correlations were present for RIA2 and chemiluminescence at concentration subgroups of > 400 nmol/L (r² = 0.869, P < 0.001), < 100 nmol/L (r² = 0.790, P < 0.001), and < 40 nmol/L (r² = 0.738, P < 0.001). Significant differences between means were present for RIA2 and chemiluminescence concentrations in the < 100 nmol/L, and < 40 nmol/L (P < 0.001) groups. Despite a significant difference in RIA1 and RIA2 results overall, there was no significant difference between RIA1 and RIA2 for any of the concentration groups. In seven cases, discrepant RIA2 and chemiluminescence results may have altered clinical decisions. Conclusions Although RIA and chemiluminescence cortisol concentrations appear highly correlated, a significant difference may exist for concentrations less than 100 nmol/L in stored canine sera. Results of chemiluminescence cortisol assays should be interpreted with caution unless the specific assay method in the laboratory has been adequately validated in dogs.     

利用放射免疫法测定水中克百威的研究

本研究建立了水样中克百威残留的放射免疫分析方法 (RIA) ,与传统的分析方法相比 ,前处理简单 ,灵敏度更高。研究结果表明 ,该方法的检出限为 0 1 75ng ml,用放射免疫测定法与高效液相色谱法检测相同水样中克百威的残留 ,两者的线性相关系数为 0 9985。     

菜籽粕对公母仔鸡甲状腺功能影响的比较研究

用放射免疫分析法研究了菜籽相对公母仔鸡血清中三碘甲腺原数酸和甲状腺素浓度影响的性别差异,考察了甲状腺肿效应与血清中甲状腺激素浓度变化关系。结果表明:(1)12％菜籽粕使仔母鸡血清三碘甲腺原氨酸浓度均值极显著降低(P<0.01)。尤其在饲喂菜籽粕4周以内影响更大,而对仔公鸡没有显著影响(P<0.05),(2)12％菜籽粕对仔鸡血清甲状腺素浓度无显著影响(P>0.05),但前期血清甲状腺浓度略有增加,后期略为下降;(3)12％菜籽粕导致8周龄仔鸡甲状腺极显著增大(P<0.01),而对肝重、肾重和腺重则无显著影响(P>0.05)。因此,菜籽粕对仔鸡血清甲状腺激素浓度的影响,存在性别差异,雌性比雄性反应敏感,在公母仔鸡饲粮中,菜籽粕用量应有所不同。     

Tissue distribution of dexamethasone in feline ocular structures following single topical application of dexamethasone as an ointment or suspension

Objective To compare the dexamethasone concentration in various structures of the feline eye following a single topical application of dexamethasone as an ophthalmic ointment or suspension. Animals studied Nineteen cats, euthanized due to reasons not related to this study, were selected and their ocular health status evaluated. Selected animals were treated with dexamethasone ointment or suspension. Procedure The concentration of dexamethasone was determined in the following structures of the eye: third eyelid, cornea, aqueous humor, iris, lens, vitreous body, and choroid/retina. The dexamethasone concentration in the eye was measured by radioimmunoassay. The applied amount of dexamethasone was 0.05 mg in 0.05 mL Isopto Dex^® ophthalmic suspension and 0.05 mL Isopto Dex^® ophthalmic ointment, respectively. Cats were treated once with ointment or suspension and were euthanized 3 h or 6 h after treatment. Results At 3 h after topical administration the highest concentrations of dexamethasone were measured in the anterior structures of the eye. The concentrations after application of ointment and suspension were comparable. However, 6 h after administration, the concentrations decreased after administration of suspension and increased further after administration of the ointment, leading to significantly higher concentrations of dexamethasone in the third eyelid, cornea and choroid/retina after treatment with ointment. Conclusion Therapeutically relevant concentrations of dexamethasone after a single topical administration were only achieved in the anterior structures of the eye. Six hours after application there was a substantially higher amount of dexamethasone in the anterior structures of cat eyes treated with ophthalmic ointment compared to ophthalmic suspension.     

Plasma somatolactin levels in coho salmon (Oncorhynchus kisutch) during smoltification and sexual maturation

Somatolactin (SL) is a novel pituitary hormone recently characterized in several fish species. Structural analyses have shown that SL belongs to the growth hormone/prolactin family, and that it is a highly conserved protein. SL is synthesized by the periodic acid/Schiff-positive cells in the pars intermedia, but has an as yet unidentified function(s). We have recently developed a homologous radioimmunoassay for coho salmon SL and measured plasma levels of SL during two stages of the coho salmon life cycle, smoltification and sexual maturation. During smoltification, plasma levels of SL changed almost in parallel with plasma levels of thyroxine; levels increased as morphological indices of smoltification appeared and decreased as smoltification was completed. Following this period, SL levels remained low until the spring prior to spawning. In a separate study, plasma levels of SL were measured in sexually maturing coho salmon that remained in fresh water throughout their life cycle. During the year of sexual maturation, plasma levels of SL gradually increased from the spring onward, reaching peak levels at the time of spawning in November and December. These data are similar to those previously reported for sexually maturing coho salmon that were maintained in seawater prior to spawning (Rand-Weaver et al. 1992). Therefore, increases in plasma SL levels occurred in sexually maturing fish irrespective of whether they were maintained in fresh water or seawater. Peak levels at spawning were higher than those observed during smoltification. Possible roles for SL in metabolism and reproduction are discussed.     

Changes in plasma insulin-like growth factor-I levels in the precociously maturing amago salmon, Oncorhynchus masou ishikawai

Seasonal changes in plasma levels of insulin-like growth factor I (IGF-I) in precociously maturing amago salmon (Oncorhynchus masou ishikawai), which matured as 1-year-olds, have been investigated. Profiles of plasma IGF-I levels were compared with changes in growth and maturity, and plasma growth hormone (GH) and thyroxine (T₄) concentrations. The maturity of the fish was determined by calculating the gonadosomatic index; in November, 100% of males and 89% females matured. In both males and females, plasma IGF-I levels increased from March to August, and subsequently, plasma IGF-I levels in the early maturing males and females declined gradually and were maintained at lower levels during the spawning period in November. Plasma GH levels were high in April, and then declined gradually through September. Thereafter, in early maturing fish, a slight increase in plasma GH levels was observed in October and November. No significant changes in plasma T₄ levels were found in the precociously maturing fish. In sharp contrast, plasma IGF-I levels in immature fish remained elevated through September, reaching a peak in October, and then gradually declined in November. In immature females, plasma T₄ and GH levels were elevated in August, reached their maximum in September and then gradually declined until November.     

奶牛分娩前后血浆类固醇激素水平变化与胎衣不下的关系

应用放射免疫分析法（ＲＩＡ）测定了２０头怀孕奶牛（其中胎衣不下（ＲＦＭ）牛和正常（ＮＲＦＭ）牛各１０头］产前１０天到产后２天外周血浆孕酮（Ｐ４）、１７β－雌二醇（１７β－Ｅ２）和雌酮（Ｅ１）的水平。结果表明，产前６～３天，ＲＦＭ牛血浆Ｐ４水平略低于ＮＲＦＭ牛（Ｐ＞０．０５），而于产前２天突然跃升并显著高于ＮＲＦＭ牛（Ｐ＜０．０５）。血浆１７β－Ｅ２水平，ＲＦＭ牛于产前７天到分娩当天显著低于ＮＲＦＭ牛（Ｐ＜０．０５），尤其是产前７天和５天。血浆Ｅ１水平，产前１０～１天ＲＦＭ牛显著低于ＮＲＦＭ牛（Ｐ＜０．０５），尤其是产前８天和４天极显著低于ＮＲＦＭ牛（Ｐ＜０．０１）；而分娩当天，ＲＦＭ牛却显著高于ＮＲＦＭ牛（Ｐ＜０．０５）。此外，Ｐ４／１７β－Ｅ２的比值，在分娩前６天和２天ＲＦＭ牛极显著和显著高于ＮＲＦＭ牛（Ｐ＜０．０１和Ｐ＜０．０５）。上述结果表明，分娩前６天时，雌酮水平显著下降和Ｐ４／１７β－Ｅ２比值显著升高可以作为奶牛胎衣不下的指征。     

用放射免疫测定法分析水中莠去津残留量的研究

以莠去津均三氮苯类结构特征 ,合成连有活性羧基的莠去津半抗原 ,通过活性酯法制备出具有生物活性的人工抗原 ,以此免疫兔子获得抗莠去津的多克隆抗体。抗体的特异性强 ,与扑灭津的交叉反应性为 93 %,与西玛津的交叉反应性为 8%。以3H标记莠去津建立的莠去津放射免疫测定法对水中莠去津添加回收率的测定表明 ,自来水的添加回收率为 88.5%～ 1 0 7.5%,运河水的添加回收率为 87.4 %～1 1 0 .9%。