Glycation levels in serum apo B proteins were measured by colorimetry of fructosamine using nitroblue tetrazolium in immunoprecipitates generated using anti-apo B serum. The serum levels of apo B glycation determined by the proposed method correlated well with the fructosamine concentrations in low-density lipoprotein (LDL) fractions separated by ultracentrifugation. Close correlations were also observed with serum concentrations of fasting blood glucose, total cholesterol and apo B protein, but those with serum triglyceride, fructosamine and HbA1 c were weak. The normal reference value was 18.1±3.65μmol/l and inter-and intra-assay coefficients of variation were 4.6-6.1% and 5.9-6.6%, respectively. Diabetes mellitus patients with vascular complications had higher serum glycated apo B levels than those without complications, matched for risk factors such as blood pressure, obesity, smoking history, age, sex, duration of diabetes, serum total cholesterol, triglyceride, high-density lipoprotein (HDL) cholesterol and lipoprotein (a). High levels of glycated apo B proteins in the blood might be an independent risk factor in addition to the established risk factors for diabetic vascular complications.

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The sugar chains of serum immunoglobulin (Ig) G, A, and M in rheumatoid arthritis (RA) patients (n=48) with elevated and normal C-reactive protein (CRP) were compared with those in age-matched healthy control subjects (n=17). The levels of agalactosylated sugar chains (GO) of serum IgG were increased significantly (p<0.01) in RA patients with elevated serum CRP, while those in RA patients with normal serum CRP remained similar to those in healthy subjects. The digalactosylated sugar chain levels were also decreased significantly (p<0.01) in serum IgA and IgM of active RA patients. Increases in levels of the bisected sugar chains were observed in serum IgG, IgA, and IgM from active RA patients. Furthermore, the GO contents of serum IgG in RA patients were correlated with their serum CRP levels (r=0.5165). These results indicated that disturbed glycosylation of Ig molecules occurs commonly in patients with active RA.

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A simple HPLC method for determination of mevalonic acid in plasma and urine is described. Mevalonic acid was converted to de-hydromevalonolactone with perchloric acid in ethyl acetate, and the product was detected by UV at 230 nm. The detection limit was 0.8 ng/ml (S/N=4). The recoveries of mevalonolactone in plasma and urine were 95.6-104.0% and 99.4-103.8%, respectively.
This HPLC method is simple and useful for clinical tests compared with conventional radioenzymatic or GC-MS.

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We synthesized a mevalonic acid derivative and conjugated it to the carrier-protein as an antigen. A mouse was immunized with this antigen, and a monoclonal antibody specific to mevalonic acid was obtained. Using this antibody and peroxidase-labeled antigen, an enzyme immunoassay (EIA) for mevalonic acid was established. The detection range of the assay was 1.5-170 pmol/ test (IC₅₀=15 pmol/ test). The cross-reactivity of the antibody with the mevalonic acid analogs, contained in the biological fluid, such as 3-hydroxy-3-methylglutaric acid was less than 0.001%. Pravastatin, an HMGCoA reductase inhibitor, was administered to healthy males (n=9), and the mevalonic acid concentration in their urine samples was measured by this enzyme immunoassay. In all subjects, mevalonic acid excretion was decreased after the pravastatin administration. The values of human urinary mevalonic acid obtained by this assay correlated (r=0.969) with those obtained by the radio-enzyme method

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The ratios of triglycerides, esterified cholesterol, free cholesterol, and phospholipids between pleural effusion and serum produce useful information for the diagnosis of chylothorax in an early stage. We can get a significantly higher ratio of triglycerides compared with those of the other three lipids in the chylothorax. In case A, whose serum triglyceride level was 280 mg/l, no chylomicron was detected by electrophoresis, and the ratios of triglycerides, esterified cholesterol, free cholesterol, and phospholipids levels were 0.64, 0.46, 0.47, and 0.46, respectively. Early stage of chylothorax was suspected. Two days later this diagnosis was confirmed by the detection of chylomicron and the higher triglyceride concentration in the pleural effusion than in the serum.
There were two patients whose pleural effusion triglyceride levels were 380 mg/l and 390 mg/l. The former had chylothorax and the latter did not. This means that a diagnosis of chylothorax by the absolute value of pleural effusion triglyceride was not always possible.
The new method, described here, would be a more precise method to diagnose chylothorax at an early stage.

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The recommended method for measuring the activity of serum γ-GT was established by Japan Society of Clinical Chemistry (JSCC). This method was based on the IFCC method, and the final concentration of GluCANA as a donor substrate and that of glycylglycine as an acceptor substrate were set at 6.0 mmol/ 1 and 150 mmol/ 1 respectively. The initial velocity under these conditions was about 77% of V_max. However, it is inappropriate to increase further the concentrations of the substrates, because of unacceptable increasing absorbance of reagent blank.
This method has the following two characteristics. One is that the amount of the sample was set small so as to avoid the turbidity to becaused by the reaction between glycylglycine and the serum, and the other is that the procedure is two-step system in which the reaction is made to start by GluCANA as the donor substrate.
It was confirmed that there was no difference in the measurement value obtained by this recommended method and the IFCC method. Therefore, this method will be used for traceability to the IFCC method. The consensus method, which is derived from this recommended method by setting the reaction temperature at 37°, will be used for traceability of the measured value by the field method. Furthermore, the consensus method is also used for valuating the enzyme reference materials and for checking of commutability.

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