An improved radioimmunoassay for measurement of pepsinogen in porcine blood samples

The study was conducted to develop a sensitive and specific radioimmunoassay (RIA) for the measurement of pepsinogen in porcine serum, and to use this test for the determination of pepsinogen concentrations in serum samples from fetuses and pigs of different ages. Compared to a previously described RIA, major improvements were made concerning the use of specific polyclonal antibodies and the use of an appropriate buffer. The assay was able to detect pepsinogen concentrations of >/=0.2 ng/mL. The recovery of pepsinogen was close to 95%. The intra-assay coefficients of variations ranged between 3.9 and 7.5% whereas the interassay ranged between 8.8 and 11.9%. These percentages correspond to a satisfactory accuracy and reproducibility of the assay. No cross-reactions were observed with the main commercially available products of the aspartic proteases family except porcine pepsin cross-reacted over 62.5 microg/mL. Pepsinogen concentrations increased steadily with increasing age of the fetuses and the pigs (P<0.05). Pepsinogen concentrations (+/-SE) in fetuses of 90-100 (n=24) and 100-110 days of pregnancy (n=36) were 0.5+/-0.1 and 5.3+/-1.3 ng/mL, respectively. In pigs of 21, 98, and 213 days of age, the pepsinogen concentrations were 290.6+/-10.8, 343.1+/-17.9 and 383.5+/-15.3 ng/mL, respectively. The results demonstrate that RIA is accurate and can be used easily to assess pepsinogen concentrations in pig sera. The test may constitute a valuable tool in epidemiological surveys and in studies related to gastric diseases in pigs.     

牛促黄体素（bLH）同源放射免疫分析法的建立

本实验用兔抗牛LH血清、~(125)I-标记的牛LH建立牛LH的放射免疫分析法。本方法灵敏度为0.12ng USDA-bLH-B-5/ml,与NIH-bTSH-S_(10),USDA-bFSH-BP_3和oPRL的交叉反应分别小于1.0％,0.1％和0。牛血浆添加USDA-bLH-B-5的回收率为100.8±4.7％,标准曲线的范围为0.019-1.25ng USDA-bLH-B-5。组内变异系数为3.4％(n=20)、组间变异系数为5.2％(n=7)。垂体兴奋试验表明本方法能灵敏、特异地测定出牛血液中LH的变化。     

Analytic validation and comparison of three commercial immunoassays for measurement of plasma atrial/A-type natriuretic peptide concentration in horses

Measurement of atrial/A-type natriuretic peptide (ANP) concentrations may be of use for assessment of cardiac disease, and reliable data on the analytic performance of available assays are needed. To assess the suitability for clinical use of commercially available ANP assays, intra-assay and inter-assay coefficient of variation and dilution parallelism were calculated for three immunoassays (RIA_Pen, RIA_Phoen, and an ELISA_Pen) using blood samples from healthy and diseased horses to cover a wide range of ANP concentrations. Further, agreement between assays was assessed using linear regression and Bland–Altman analyses. For all assays, precision was moderate but acceptable and dilution parallelism was good. All assays showed analytic performance similar to other immunoassays used in veterinary medicine. However, the results from the three assays were poorly comparable. Our study highlights the need for an optimised species-specific assay for equine samples.