Development of a protein assay with copper chelator chromeazurol B, based on the biuret reaction.

This study aimed to provide a novel and highly sensitive protein assay based on the biuret reaction and using chromeazurol B, a metal chelate compound. The method consists of two reagents and an automated analyzer. First, a complex of copper and protein (biuret reaction) is formed.

Comparison of the Japan Society of Clinical Chemistry reference method and CDC method for HDL and LDL cholesterol measurements using fresh sera.

Objectives: In 2009, the Japan Society of Clinical Chemistry (JSCC) recommended a reference method for the measurement of serum high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels. This automated method uses cholesterol esterase-cholesterol dehydrogenase to measure cholesterol levels in fractions obtained after ultracentrifugation and dextran sulfate/magnesium chloride precipitation. In the present study, using fresh samples, we compared the LDL-C and HDL-C levels measured using this method with those measured using the traditional Centers for Disease Control and Prevention (CDC)-beta-quantification (BQ) method.

New colorimetric method with bromocresol purple for estimating the redox state of human serum albumin.

Oxidative damage results in protein modification and is observed in many diseases, such as heart failure and renal insufficiency. Human serum albumin is an index of oxidative change and is conventionally measured using high-performance liquid chromatography (HPLC). Although this method is more sensitive than the colorimetric method, it is time-consuming for clinical practice and the sera must be stored at -80°C before analysis.

Protein C and protein S deficiencies may be related to survival among hemodialysis patients.

Background: Thrombophilia due to protein C (PC) and protein S (PS) deficiencies is highly prevalent among patients with stage 5 chronic kidney disease and is reported to arise due to extracorporeal circulation during hemodialysis (HD). This study aimed to evaluate the relationship between HD treatment and thrombophilia.

Methods: A total of 114 Japanese patients on maintenance HD (62 men, 52 women) were followed during 2008-2011.

Significance of a Family-based Study of Hereditary Thrombosis: A Single-family Case Series of Protein C Deficiency.

Thrombophilia is a serious unpredictable complication caused by gene mutations, resulting in anticoagulant deficiencies. We herein report a single-family case series of protein C (PC) deficiency. Case 1 involved a Japanese man whose PC deficiency resulted in severe systemic thrombosis.

The Influence of Pre-Analytical Factors on the Analysis of Circulating MicroRNA.

Background: MicroRNAs (miRNA) are expected as useful biomarkers for various diseases. We studied the pre-analytical factors causing variation in the analysis of miRNA.

Material And Methods: Blood samples were collected from 25 healthy subjects.

Novel enzymatic method for assaying Lp-PLA in serum.

Background: Measurement of lipoprotein-associated phospholipase A (Lp-PLA) can be used as an adjunct to traditional cardiovascular risk factors for identifying individuals at higher risk of cardiovascular events. This can be performed by quantification of the protein concentration using an ELISA platform or by measuring Lp-PLA activity using platelet-activating factor (PAF) analog as substrate. Here, an enzymatic Lp-PLA activity assay method using 1-O-Hexadecyl-2-acetyl-rac-glycero-3-phosphocholine (rac C PAF) was developed.

Characterization and application of a novel nicotinamide mononucleotide adenylyltransferase from Thermus thermophilus HB8.

Herein, we describe a novel enzymatic cycling method to measure nicotinamide mononucleotide (NMN) or nicotinic acid mononucleotide (NaMN), which are precursors of NAD biosynthesis. A gene encoding an NMN adenylyltransferase (NMNAT, EC 2.7.

Preliminary evaluation of an improved enzymatic assay method for measuring potassium concentrations in serum.

Background: K(+) has important physiological functions. K(+) concentrations in serum are generally determined using ion-selective electrodes (ISEs), though measurement using reagents in aqueous medium is also useful.

Methods: K(+) concentrations were measured using recombinant inosine 5'-monophosphate dehydrogenase (IMPDH), which was activated only by K(+) and NH4(+).

Highly sensitive reversed-phase high-performance liquid chromatography assay for the detection of Tamm-Horsfall protein in human urine.

Background: Tamm-Horsfall protein (also known as uromodulin) is the most abundant urinary protein in healthy individuals. Since initially characterized by Tamm and Horsfall, the amount of urinary excretion and structural mutations of Tamm-Horsfall protein is associated with kidney diseases. However, currently available assays for Tamm-Horsfall protein, which are mainly enzyme-linked immunosorbent assay-based, suffer from poor reproducibility and might give false negative results.

Total cholesterol performance of Abell-Levy-Brodie-Kendall reference measurement procedure: Certification of Japanese in-vitro diagnostic assay manufacturers through CDC's Cholesterol Reference Method Laboratory Network.

Background: Accurate measurement of total cholesterol (TC) is important for cardiovascular disease risk management. The US Centers for Disease Control and Prevention (CDC) and Cholesterol Reference Method Laboratory Network (CRMLN) perform Abell-Levy-Brodie-Kendall (AK) reference measurement procedure (RMP) for TC as a secondary reference method, and implement Certification Protocol for Manufacturers. Japanese CRMLN laboratory at Osaka performed the AK RMP for 22 years, and conducted TC certification for reagent/calibrator/instrument systems of six Japanese manufacturers every 2 years for 16 years.

HDL cholesterol performance using an ultracentrifugation reference measurement procedure and the designated comparison method.

Background: Accurate high-density lipoprotein cholesterol (HDL-C) measurements are important for management of cardiovascular diseases. The US Centers for Disease Control and Prevention (CDC) and Cholesterol Reference Method Laboratory Network (CRMLN) perform ultracentrifugation (UC) reference measurement procedure (RMP) to value assign HDL-C. Japanese CRMLN laboratory (Osaka) concurrently runs UC procedure and the designated comparison method (DCM).

LDL cholesterol performance of beta quantification reference measurement procedure.

Background: Accurate measurement of blood lipids is crucial in cardiovascular disease risk management. The Centers for Disease Control and Prevention (CDC) Cholesterol Reference Method Laboratory Network (CRMLN) has assured the accuracy of these measurements for over 20 years using beta quantification (BQ) method as reference measurement procedure (RMP) for high- and low-density lipoprotein cholesterol (HDL-C, LDL-C). Only limited data exist about the performance of the BQ RMP.

Validation of homogeneous assays for HDL-cholesterol using fresh samples from healthy and diseased subjects.

Background: High-density lipoprotein-cholesterol (HDL-C) is a negative risk factor for cardiovascular events. Although several homogeneous HDL-C assays are available, their accuracy has not been validated, particularly in subjects with disease. We aimed to clarify whether HDL-C concentrations measured by homogeneous assays [HDL-C (H)] agree with those determined by the reference measurement procedures [HDL-C (RMP)] using ultracentrifugation and precipitation with heparin-manganese reagent in fresh clinical samples.

A multicenter study on the precision and accuracy of homogeneous assays for LDL-cholesterol: comparison with a beta-quantification method using fresh serum obtained from non-diseased and diseased subjects.

Background: Homogeneous assays for low-density lipoprotein-cholesterol (LDL-C) have good precision and are pretreatment-free procedures. However, their accuracies have been questioned, especially in diseased subjects. In this study, we aimed to verify whether LDL-C levels determined by homogeneous assays [LDL-C (H)] agree with those determined by a beta-quantification method [LDL-C (BQ)] in fresh clinical samples.

[ISO 15189 accreditation and future perspectives-Chairmen's introductory remarks].

Recently, transparency of the organization administration and patient-centered medical care such as patient service and satisfaction have been demanded in the medical field. The role of the clinical laboratory, one of the organizations in the medical field, is to provide quality laboratory data to improve diagnosis and treatment. Other than clinical laboratory facilities, education and the ability of staff to use it, the management of the organization must be appropriate to produce high quality laboratory data.

[Distributions and spreads of antimicrobial drug-resistant microorganisms in Saga prefecture].

We investigated the distribution of drug-resistant organisms to clarify transmission of the organisms. Drug-resistant organisms were surveyed in 12 facilities in 4 districts of Saga prefecture for 2 years, and were analyzed by beta-lactamase typing, antimicrobial susceptibility tests and pulsed-field gel electrophoresis (PFGE). The number of isolates was 111,505 for the 2 years.

[Microbiological and clinical features of nine cases with nocardial infections].

Following recent advance in medical technology, the increase of immunocompromised patients results in an increase of opportunistic infections such as nocardiosis. However, little is known about relationships between clinical features of nocardial infections and each Nocardia species, especially newly identified ones. Therefore, we identified clinical isolates of Nocardia species by genetic methods and analyzed clinical features of nocardiosis.

Enzymatic assay of phosphatidylethanolamine in serum using amine oxidase from Arthrobacter sp.

Background: In human serum, as for phospholipids not containing choline, phosphatidylethanolamine (PE) exists approximately 5% in a whole phospholipid. PE is well known as one of the main components of biological membranes, and also plays important roles that contribute to apoptosis and cell signaling. However, it could not measure PE with other phospholipids due to a lack of choline in them.

Ten-year evaluation of homogeneous low-density lipoprotein cholesterol methods developed by Japanese manufacturers. Application of the Centers for Disease Control and Prevention/Cholesterol Reference Method Laboratory Network lipid standardization protocol.

Aim: The risk index for atherosclerotic cardiovascular diseases in the Japanese metabolic syndrome-focused health checkup program was changed from total cholesterol (TC) to low-density lipoprotein cholesterol (LDL-C). We discuss the validity of this change with respect to standardization.

Methods: The beta-quantification procedure of the Centers for Disease Control and Prevention (CDC) uses the LDL-C reference value as a target.

[Approach for prevention of medical test malpractice using ISO 15189].

With the increasing need for medical laboratory data, the importance of the medical laboratory in medical care has grown exponentially. Therefore, it is necessary that the medical laboratory provide the doctor and the patient receiving medical care with accurate, precise, and reliable medical laboratory data. Quality assurance and safety management in the medical laboratory are necessary to prevent medical test malpractice, which would lead to a medical accident, and to manage the overall processes required to provide high quality medical laboratory data.

Development of a new measurement method for serum calcium with chlorophosphonazo-III.

Background: Although serum calcium has been measured using the o-cresolphthalein complexone (oCPC) method in the clinical laboratory, this method still has some problems regarding linearity and reagent stability. We developed a new measurement procedure using chlorophosphonazo-III (CPZ-III: 2,7-bis (4-chloro-2-phosphonophenylazo) -1,8- dihydroxy-3, 6-naphthalenedisulphonic acid, disodium salt) as a chelator with an acid medium for serum calcium measurement. The present method showed better linearity and reagent stability compared with the oCPC method.

[ISO 15189 accreditation acquisition and the procedure].

Recently, the transparency of customer service and organization administration has been required in many fields. Objective evaluation by a third person is necessary. This also applies to medical institutions; whether the responsibility for explanation to patients and the transparency of medical activities are open is currently emphasized.