Takahiro Imazato

Decrement of serum cartilage oligomeric matrix protein (COMP) in rheumatoid arthritis (RA) patients achieving remission after 6 months of etanercept treatment: comparison with CRP, IgM-RF, MMP-3 and anti-CCP Ab.

OBJECTIVE The aim of this study was to evaluate whether serum COMP can estimate the therapeutic response of RA after 6 months of treatment with etanercept. METHODS Forty-five RA patients receiving 25 mg of etanercept twice a week for 6 months were registered in this prospective observational study. Clinical response to the therapy was evaluated by DAS 28. Laboratory variables- COMP, CRP, ESR, IgM-RF, MMP-3, and anti-CCP Ab -were assessed at baseline and after 6 months of treatment. We assessed the correlations between serum COMP and other variables and whether serum COMP is associated with DAS28 remission. RESULTS Serum COMP correlated with DAS28-ESR (p < 0.05, r = 0.40) at baseline. At 6 months of etanercept treatment, 10 patients entered remission (DAS28-ESR < 2.6) whereas the other 35 patients did not (DAS28-ESR > 2.6). The decrement of serum COMP at 6 months was significant in the remission group (N = 10) but not in the non-remission group (N = 35). On the other hand, CRP, ESR and MMP-3 decreased at 6 months regardless of remission status. IgM-RF titer as well as anti-CCP Ab titer did not differ at 6 months. CONCLUSIONS Serum COMP at baseline reflects clinical disease activity of RA. Serum COMP is a valuable serologic marker to identify the subset of RA patients achieving remission during treatment with etanercept.

Selective chemiluminescence method for monitoring of vitamin K homologues in rheumatoid arthritis patients

Vitamin K is a fat-soluble vitamin involved in blood coagulation and bone metabolism. The detection and monitoring of vitamin K homologues in rheumatoid arthritis (RA) patients is a challenging problem due to the smaller concentrations of vitamin K and the presence of several interfering medications. Therefore, this study aimed to develop a new highly sensitive and selective chemiluminescence (CL) method designated to quantify vitamin K homologues in plasma of RA patients including phylloquinone (PK, vitamin K(1)), menaquinone-4 (MK-4, vitamin K(2)) and menaquinone-7 (MK-7, vitamin K(2)). The method was based on the unique photochemical properties of vitamin K homologues that were exploited for selective luminol CL reaction. The correlation coefficients of 0.998 or more were obtained in the concentration ranges of 0.1-100 ng mL(-1) vitamin K homologues. The detection limits were 0.03-0.1 ng mL(-1) in human plasma for vitamin K homologues. The developed HPLC-CL system was successfully applied for selective determination of vitamin K homologues in plasma of RA patients. The developed method may provide a useful tool for monitoring vitamin K homologues in different clinical studies such as RA, osteoporosis and hepatocellular carcinoma in which vitamin K is intervented.

Automated analysis of the serum antioxidative activities against five different reactive oxygen species by sequential injection system with a chemiluminescence detector.

BACKGROUND There is a growing evidence that reactive oxygen species (ROS) may cause many pathologic conditions including chronic diseases, neurodegenerative disorders, cancer and aging. There are a number of methods to measure the total antioxidative activity of the serum. However, since the lifetime and oxidative activity of various types of ROS are all different, to measure simply the total antioxidative activity of the serum is not enough. Therefore, to aid the diagnosis and to improve the therapeutic strategy, it is important to develop a simple and reliable method of assaying antioxidative activity of the serum. METHODS A method that combines sequential injection analysis (SIA) and luminol chemiluminescence (CL) detection was employed for the measurement of antioxidative activities of human serum. We collected sera from healthy subjects (n=42) and patients with diabetes (n=39) and rheumatoid arthritis (n=25) and tested the sensitivity, reproducibility and reliability of our method. RESULTS Since the operation is automatically controlled by a personal computer, we obtained a satisfactory repeatability without the need of much manpower. The time required for obtaining the antioxidative activity against one ROS for one individual is less than 3min. Although the value of antioxidative activity varies from subject to subject, there were a certain relationship between the disease and the antioxidative values of each type of ROS. The results suggest that the measurement of antioxidative activity against different ROS may provide us with valuable information regarding the disease state. CONCLUSIONS The evaluation of antioxidative activities against each ROS by the proposed method should be more informative to understand the antioxidative status of biological fluid.

Determination of acrolein in serum by high‐performance liquid chromatography with fluorescence detection after pre‐column fluorogenic derivatization using 1,2‐diamino‐4,5‐dimethoxybenzene

Acrolein is a major unsaturated aldehyde that is generated during the lipid peroxidation process. The measurement of acrolein in biological samples should be useful to estimate the degree of lipid peroxidation and to evaluate the effect of hazardous properties of acrolein on human health. In this study, a highly sensitive and selective high-performance liquid chromatography with fluorescence detection method was developed for the determination of acrolein in human serum. The proposed method involves the pre-column fluorogenic derivatization of acrolein with 1,2-diamino-4,5-dimethoxybenzene (DDB) as a reagent. The fluorescent derivative of acrolein could be detected clearly without any interfering reagent blank peaks because DDB does not have intrinsic fluorescence itself, and the detection limit was 10 nM (signal-to-noise ratio = 3). The proposed method could selectively detect acrolein in human serum with a simple protein precipitation treatment.

Determination of 4-hydroxy-2-nonenal in serum by high-performance liquid chromatography with fluorescence detection after pre-column derivatization using 4-(N,N-dimethylaminosulfonyl)-7-hydrazino-2,1,3-benzoxadiazole.

4-Hydroxy-2-nonenal (4HNE) is a major aldehyde generated during lipid peroxidation. The clinical monitoring of 4HNE in biological fluids should be useful for the early diagnosis of several diseases involving lipid peroxidation, such as rheumatoid arthritis, Parkinsons disease and cancer. In this study, an HPLC with fluorescence detection method was developed for the determination of 4HNE in human serum. The proposed method involves the extraction of 4HNE from human serum by sub-zero temperature extraction and fluorescent labeling of 4HNE with 4-(N,N-dimethylaminosulfonyl)-7-hydrazino-2, 1,3-benzoxadiazole. The lower detection limit (signal-to-noise ratio = 3) of the method was 0.06 μm in serum. The proposed method was successfully applied to the measurement of 4HNE in sera obtained from patients with rheumatoid arthritis.

Determination of the ratio between mercaptalbumin and nonmercaptalbumin by HPLC with fluorescence probe specifically binding to albumin

A simple and selective HPLC-fluorescence (FL) method with FL probe, 4-[4-(4-dimethylaminophenyl)-5-phenyl-1H-imidazol-2-yl]benzoic acid methyl ester (DAPIM), for simultaneous determination of mercaptalbumin (HMA) and nonmercaptalbumin (HNA1) was developed. After HMA and HNA1 were separated on an ion-exchange column, they were on-line and post-column mixed with DAPIM. The DAPIM-albumin complex produces FL (λex 370nm and λem 510nm); however, DAPIM solution never gives the FL. Based on this mechanism, selective determination of HMA and HNA1 were achieved without any pretreatment and interfering peak. The proposed method was applied to the measurement of HMA and HNA1 in human serum of healthy volunteers and diabetes mellitus patients.