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The urinary excretion of valproic acid (VPA) and its metabolites (3-keto VPA, 3-OH VPA, and VPA-glucuronide) in 6 epileptic patients was studied using gas chromatography-mass spectrometry. The amount of VPA and 3-OH VPA excreted in the urine was low (0.1-0.5% of the dose of VPA and 0.6-1.5% of the dose of 3-OH administered). The amount of 3-keto VPA and glucuronide (VPA-Glu) excreted was marked (5.8-26.2% and 13.1-88.7% of the dose of VPA administered, respectively). The urinary excretion of VPA and its metabolites by patients who have taken a normal amount of a VPA preparation was almost the same as that of healthy volunteers. Two epileptic patients who took a large amount of the VPA preparation showed a high excretion of VPA-Glu without an increase in their plasma VPA-Glu.

We previously encountered a patient with epilepsy who exhibited rapid elimination of sustained-release valproic acid (VPA) administered at the dose of 2.8 g/d as a sodium salt. The purpose of this study was to clarify the relationship between the VPA elimination rate and the proportion of the dose excreted in urine as its glucuronide conjugate (VPA-G) in epileptic patients. Twenty-four-hour urine was collected from four epileptic patients who had taken VPA orally (age: 16-39 y, weight: 50-63 kg, dose: 1.0-2.8 g/d). VPA and its metabolites were detected by gas chromatography-mass spectrometry. The amounts of VPA, VPA-G, 3-keto VPA, and 3-OH VPA excreted in the 24-h urine were 1.8-13.2, 178-2158, 125-320, and 8.6-18.7 mg (converted into VPA), respectively, and 0.2-0.5, 20.5-88.7, 5.8-18.7, and 0.6-1.0% of the dose administered, respectively. The dose of VPA correlated well with the proportion of the dose excreted in urine as VPA-G in each patient, and the patients administered a high dose excreted a large amount of VPA-G in the urine. Thus, differences in the VPA-G production rate may be one of the major variable factors affecting the elimination of administered VPA. We also present a dynamic model of VPA in the kidney which may explain the VPA elimination phenomena in humans on the basis of the data obtained here regarding the concentrations of VPA and its metabolites in plasma and their urinary excretion levels.

A new method of staining histamine in rat mast cell granules in formalin fixed paraffin section was developed.Mast cells of several organs of formalin fixed paraffin sections were stained well in red with orcein-water blue as well as in purple with toluidine blue.But only mast cells in dermis showed a different appearance in orcein-water blue stain and toluidine blue stain. The results of an electrophoretic study, diamine oxidase treatment and compound 48/80 treatment of rat lead to the conclusion that the substance stained in red with orcein may be histamine.It was shown that histamine in rat mast cell granule is fixed even by formalin, a finding contrary to previous studies.The mast cell contains many substances in its granules. Histamine is one of the principal substances in granules. The histochemical demonstration of histamine is significant in the study of mast cells. It has been considered that histamine in tissue easily dissolves out by formalin fixation, thus known staining methods require a complicated technique in fixation or staining because of the solubility of histamine (3, 4, 7).In the present study, we obtained evidence that histamine can be detected even in formalin fixation. This article reports on the effectiveness of orcein in staining histamine in formalin fixed paraffin sections. MATERIALS AND METHODSAdult male Wister rats weighing 200-300 g were anesthetized with ether and exanguinated by cutting the carotid arteries, except when otherwise specified. The tongue, skin, lung, stomach and ileum were removed and fixed overnight or longer in 10% formalin. All specimens were embedded in paraffin, cut in 5µm sections with the microtome, deparaffinized and used for staining.Staining methods Orcein-water blue stain :The orcein-water blue solution was made by dissolving 0.98 g of orcein (Wako Chem. Co., Ltd., Japan) in 60 ml of 100% ethyl alcohol to which was added 1 ml of concentrated HCl mixed with 0.02 g of water blue (also Wako Co.) dissolved in 40 ml of distilled water (2). The solution was stirred thoroughly, filtrated and used for staining. Sections were treated with orcein-water blue solution for 10 min and differentiated by 60% alcohol with 1 % concentrated HCI, dehydrated, cleared and mounted.