This paper is the ninth in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 °C and the certification of reference preparations. Other parts deal with: Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes; Part 2. Reference procedure for the measurement of catalytic concentration of creatine kinase; Part 3. Reference procedure for the measurement of catalytic concentration of lactate dehydrogenase; Part 4. Reference procedure for the measurement of catalytic concentration of alanine aminotransferase; Part 5. Reference procedure for the measurement of catalytic concentration of aspartate aminotransferase; Part 6. Reference procedure for the measurement of catalytic concentration of γ-glutamyltransferase; Part 7. Certification of four reference materials for the determination of enzymatic activity of γ-glutamyltransferase, lactate dehydrogenase, alanine aminotransferase and creatine kinase at 37 °C; Part 8. Reference procedure for the measurement of catalytic concentration of α-amylase. The procedure described here is derived from the previously described 30 °C IFCC reference method. Differences are tabulated and commented on in Appendix 1.

The purpose of the present study is to establish the influence of age on serum biochemistry reference intervals (RIs) for unweaned calves and recently-weaned piglets using large number of animals sampled at different ages from populations under different season trials. Specifically, milk replacer (MR)-fed calves from April–July 2017 ( n = 60); from December 2016–March 2017 ( n = 76) and from April–August 2018 ( n = 57) and one group of healthy weaned piglets ( n = 72) were subjected to the study. Serum enzymes and metabolites of calves at age of 24 h (24 h after colostrum intake), 2, 5, and 7 weeks from merged trials and piglets at 0, 7, and 14 days post-weaning (at 21, 28, and 35 days of age) were studied. The main variable is age whereas no major trial- or sex-biased differences were noticed. In calves, ALT, AST, GGT, GPx, SOD, NEFAs, triglycerides, glucose, creatinine, total protein, and urea were greatly elevated ( p < 0.001) at 24 h compared with other ages; glucose, creatinine, total protein, and urea constantly decreased through the age; cholesterol's lowest level ( p < 0.001) was found in 24 h compared with other ages and the levels of haptoglobin remained unchanged ( p > 0.1) during the study. In comparison with the adult RIs, creatinine from 24 h, NEFAs from 2 w, GGT from 5 w, and urea from 7 w are fully comparable with RIs or lie within RIs determined for adult. In piglets, no changes were noticed on glucose ( p > 0.1) and haptoglobin ( p > 0.1) and there were no major changes on hepatic enzymes (ALT, AST, and GGT), total protein, creatinine and urea even though several statistical differences were noticed on 7 days post-weaning. Cholesterol, triglycerides, NEFAs, cortisol and PigMAP were found increased ( p < 0.05) while TNF-alpha was found less concentrated ( p < 0.001) at 0 days post-weaning compared with other times. Moreover, the RIs of creatinine and GGT are fully comparable with RIs or lie within RIs determined for adult. In conclusion, clinical biochemistry analytes RIs were established for unweaned calves and recently-weaned piglets and among them some can vary at different ages.

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1 Cyclo-oxygenase (COX), the enzyme responsible for the conversion of arachidonic acid (AA) to prostaglandin H 2 (PGH 2 ), exists in two forms, termed COX-1 and COX-2 which are encoded by di erent genes. COX-1 is expressed constitutively and is known to be the site of action of aspirin and other nonsteroidal anti-in¯ammatory drugs. COX-2 may be induced by a series of pro-in¯ammatory stimuli and its role in the development of in¯ammation has been claimed. 2 Endothelial cells are an important physiological source of prostanoids and the selective induction of COX-2 activity has been described for ®nite cultures of endothelial cells, but not for permanent endothelial cell lines. 3 The HUV-EC-C line is a permanent endothelial cell line of human origin. We have determined the COX activity of these cells under basal conditions and after its exposure to two di erent stimuli, phorbol 12-myristate 13-acetate (PMA) and interleukin-1b (IL-1b). 4 Both PMA and IL-1b produced dose-and time-dependent increases of the synthesis of the COXderived eicosanoids. These increases were maximal after the treatment with 10 nM PMA for 6 to 9 h. Under these conditions, the main eicosanoid produced by the cells was PGE 2 . 5 The increase of COX activity by PMA or IL-1b correlated with an increase of the enzyme's apparent V max , whilst the a nity for the substrate, measured as apparent K m , remained una ected. 6 Treatment of the cells with PMA induced a time-dependent increase in the expression of both COX-1 and COX-2 mRNAs. Nevertheless, this increase was re¯ected only as an increase of the COX-2 isoenzyme at the protein level. 7 The enzymatic activity of the PMA-induced COX was measured in the presence of a panel of enzyme inhibitors, and the IC 50 values obtained were compared with those obtained for the inhibition of human platelet COX activity, a COX-1 selective assay. Classical non-steroidal anti-in¯ammatory drugs (NSAIDs) inhibited both enzymes with varying potencies but only the three compounds previously shown to be selective COX-2 inhibitors (SC-58125, NS-398 and nimesulide) showed higher potency towards the COX of PMA-treated HUV-EC-C. 8 Overall, it appears that the stimulation of the HUV-EC-C line with PMA selectively induces the COX-2 isoenzyme. This appears to be a suitable model for the study of the physiology and pharmacology of this important isoenzyme, with a permanent endothelial cell line of human origin.

The new turbidimetric immunoassay (Turbovet canine CRP, Acuvet Biotech) is a rapid, robust, precise, and accurate method for the quantification of cCRP. The method can be easily set up in automated analyzers, providing a suitable tool for routine clinical use.

Reference intervals are commonly used as a decision-making tool. In this review, we provide an overview on “big data” and reference intervals, describing the rationale, current practices including statistical methods, essential prerequisites concerning data quality, including harmonization and standardization, and future perspectives of the indirect determination of reference intervals using routine laboratory data.

The primary reference measurement procedures (PRMPs) for the international standardization of catalytic concentration measurements of alpha-amylase, alanine aminotransferase, aspartate aminotransferase (AST), creatine kinase (CK), gamma-glutamyltransferase and lactate dehydrogenase have been performed in reference laboratories for several years. The IFCC Committee on Reference Systems for Enzymes and two reference laboratories, with official accreditation for the PRMPs, have collected useful information on some of the steps of the reference procedures that require special attention. This document comprises errata corrige for minor mistakes in published PRMPs for AST and CK. Several notes on the PRMPs are emphasized. This includes details that are very important for improved standardization, and general suggestions for reducing measurement uncertainty.

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