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Background : A multicenter study conducted in Southeast Asia to derive reference intervals (RIs) for 72 commonly measured analytes (general chemistry, inflammatory markers, hormones, etc.) featured centralized measurement to clearly detect regionality in test results. The results of 31 standardized analytes are reported, with the remaining analytes presented in the next report. Method : The study included 63 clinical laboratories from South Korea, China, Vietnam, Malaysia, Indonesia, and seven areas in Japan. A total of 3541 healthy individuals aged 20 -65 years (Japan 2082, others 1459) were recruited mostly from hospital workers using a well-defined common protocol. All serum specimens were transported to Tokyo at − 80 ° C and collectively measured using reagents from four manufacturers. Three-level nested ANOVA was used to quantitate variation (SD) of test results due to region, sex, and age. A ratio of SD for a given factor over residual SD (representing net between-individual variations) (SDR) exceeding 0.3 was considered significant. Traceability of RIs was ensured by recalibration using value-assigned reference materials. RIs were derived parametrically. Results : SDRs for sex and age were significant for 19 and 16 analytes, respectively. Regional difference was significant for 11 analytes, including high density lipoprotein (HDL)-cholesterol and inflammatory markers. However, when the data were limited to those from Japan, regionality was not observed in any of the analytes. Accordingly, RIs were derived with or without partition by sex and region. Conclusions : RIs applicable to a wide area in Asia were established for the majority of analytes with traceability to reference measuring systems, whereas regional partitioning was required for RIs of the other analytes.

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are suggested to be important neurosteroids. We investigated steroid sulfatase (STS) in human temporal lobe biopsies in the context of possible cerebral DHEA(S) de novo biosynthesis. Formation of DHEA(S) in mature human brain tissue has not yet been studied. 17a-Hydroxylase/C17-20-lyase and hydroxysteroid sulfotransferase catalyze the formation of DHEA from pregnenolone and the subsequent sulfoconjugation, respectively. Neither their mRNA nor activity were detected, indicating that DHEA(S) are not produced within the human temporal lobe. Conversely, strong activity and mRNA expression of DHEAS desulfating STS was found, twice as high in cerebral neocortex than in subcortical white matter. Cerebral STS resembled the characteristics of the known placental enzyme. Immunohistochemistry revealed STS in adult cortical neurons as well as in fetal and adult CajalRetzius cells. Organic anion transporting proteins OATP-A, -B, -D, and -E showed high mRNA expression levels with distinct patterns in cerebral neocortex and subcortical white matter. Although it is not clear whether they are expressed at the blood-brain barrier and facilitate an influx rather than an efflux, they might well be involved in the transport of steroid sulfates from the blood. Therefore, we hypothesize that DHEAS and/or other sulfated 3b-hydroxysteroids might enter the human temporal lobe from the circulation where they would be readily converted via neuronal STS activity. Keywords: arylsulfatase C, brain, hydroxysteroid sulfotransferase, 17a-hydroxylase/c17-20-lyase, solute carrier family 21, neurosteroid.

This paper is the second in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees 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 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 gamma-Glutamyltransferase; Part 7. Certification of Four Reference Materials for the Determination of Enzymatic Activity of gamma-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary reference values is also in preparation. The pro- described 30 degrees C IFCC reference method (1). Differences are tabulated and commented on in Appendix 3.

This paper is the third in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees 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 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 gamma-Glutamyltransferase; Part 7. Certification of Four Reference Materials tamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary upper reference limits is also in preparation. The procedure described here is deduced from the previously described 30 degrees C IFCC reference method (1). Differences are tabulated and commented on in Appendix 1.