3-Ketobutylidene β-2-chloro-4-nitrophenylmaltopentaoside (3KB-βCNPG5) was used for the determination of the chloride ion concentration in serum and urine. This enzymatic assay for the chloride ion, which is based on the determination of α-amylase using 3KB-β CNPG5, has a wide dynamic range (0-400mmol/l) and is less affected by other endogenous anions in biological fluids than other methods. This method is highly sensitive and stable for determing the chloride-ion concentration and can be applied to undiluted samples of sera and urine.

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Free radicals have been considered to play an important role in the pathogenesis of gastric mucosal lesions. We investigated the lipid radical-scavenging effect of antiulceratives such as Teprenone, Praunotol, Gefarnate, Sofalcone, Rebamipide and Benexate Hydrochloride Betadex using AMVN-induced peroxidation of linoleic acid. Teprenone did not affect the oxygen uptake rate (R) in the lipid peroxidation but prolonged the initiation time of the oxygen uptake (Tinh), Praunotol and Gefarnate reduced R but did not prolong T inh, Sofalcone, Rebamipide and Benexate Hydrochloride Betadex did not affect either R or T inh.

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We estimated HDL-cholesterol (HDL-C) in control human sera (n=17), pooled human sera with different HDL-C levels (n=5) and fresh human sera (n=12) by three precipitation methods based on different principles: phosphotungstate MgCl2 method (4 kits), polyethylene glycol method (3 kits) and isoelectric point method (1 kit) and the values were compared by HPLC method. All HDL-C values measured by precipitation methods were significantly lower than those by the HPLC method. Especially, the values measured by the isoelectric point method and phosphotungstate MgC12 method were remarkably lower than those by HPLC method. The polyethylene glycol method, however, showed values closest to those by the HPLC method. The most remarkable differences between values measured by precipitation method and HPLC method were noted in the control sera group and the largest inter-kit deviation was also noted in this group. The recovery rate of HDL-C in the supernatant fractions was the lowest and the deviation was the largest in this group. Analysis by the HPLC method of the supernatants revealed that there was no contamination from lipoproteins other than HDL in any case, although the distribution in sizes of HDL were often different from those of original sera. In conclusion, we speculated that HDL-C values lower and more variable than those demonstrated by HPLC were shown by precipitation methods due to the possible of precipitation of a part of the HDL by the reagents as well as the differences in reactivity of reagents to aggregated lipoprotein particles and apo-E rich HDL in the samples.

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A method for quantitative analysis of p-hydroxy-N-benzylamphetamine which is the main urinary metabolite of benzphetamine in rats was developed using HPLC. The rat urine sample was adjusted to pH 6 with 0.1 M acetic acid. Each sample was applied to a solid phase extraction column, Bond Elut Certify which contains the octyl silyl group and cation exchange functional group. After subsequently washing the column with water, 0.01 M acetic acid and methanol, p-hydroxy-N-benzylamphetamine was eluted with dichloromethane: isopropanol: 28% ammonium hydroxide =96.04: 1.96: 2.00 (v/v%). The eluate was evaporated and the residue dissolved in acetonitrile: PIC B-5 (5 mM l-pentane sulfonic acid) =5: 95 was analysed by HPLC. The calibration curves showed good linearity between the following two concentration ranges: 0.138-27.5 nmol/ml and 6.90-1,380 nmol/ml. The detection limit of p-hydroxy-Nbenzylamphetamine was 0.021 nmol. The mean recovery was 103.3%. The amount of urinary phydroxy-N-benzylamphetamine obtained from rats after subcutaneous injection of 5mg/kg or 50mg/kg of benzphetamine hydrochloride was determined by the present method. As a result, about 8% of benzphetamine was excreted as p-hydroxy-N-benzylamphetamine and almost all of p-hydroxy-N-benzylamphetamine was excreted within 24 h.

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We found thioglycerol to be stable activator for CK, and can replace NAC as a CK assay reagent. Thioglycerol was more stable than NAC, and did not produce oxidizing substances which inhibit CK activity. Thus, it is preferable to formulate a stable reagent with a longer shelf life. CK values in human serum samples tested with the thioglycerol-activated reagent agreed with the JSCC consensus method (automated method). The thioglycerol-activated CK assay was suitable for a stable liquid-type reagent.

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