[in Japanese]

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The molecular pathogenesis of epilepsy had been long undiscovered though epilepsy was described even in ancient Greek age and has been well known as one of the commonest neurological disorders ever since. However, despite recent advances in molecular biology, the molecular mechanism of epilepsy remains a puzzle, assumingly due to its heterogeneous nature. Recently, genetic causes have been identified in certain epilepsy syndromes in which the inheritance is evident, such as progressive myoclonic epilepsy and rare familial idiopathic epilepsy syndromes. Interestingly, genetic abnormalities identified in such syndromes in which the phenotypes are similar to common idiopathic epilepsies were detected in genes encoding ion channels expressed in the brain. Thus such epilepsy syndromes are disorders of ion channels, i. e., “channelopathies”. The list of ion channel abnormalities that are associated with childhood epilepsy is expanding. Genetic identifier in epilepsy syndromes, except for severe myoclonic epilepsy in infancy, were familial epilepsy syndromes showing dominant inheritance with high penetrance while common idiopathic epilepsies do not show obvious inheritance. However, the similarities in symptomatology between such familial epilepsies and common idiopathic epilepsy may provide us with clues to the genetics of common idiopathic epilepsies. Further understanding of molecular mechanisms underlying epilepsy should open a new avenue to diagnosis and treatments for epilepsy based upon the pathomechanism.

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Electrophoresis with cellulose-acetate membrane has been used as a convenient method to detect isozymes of alkaline phosphatase (ALP) such as small intestine-type ALP (SI-ALP) and bone type ALP. It is, however, desirable to develop a quantitative method in which ALP types can distinctively be detected. We developed a method for measuring the catalytic activity of SI-ALP by an inhibiting method using L-phenylalanine.
Using a reagent recommende d by the JSCC transferable method for ALP, the catalytic activities of both liver and bone type ALPs were inhibited by 53% in the presence of 50mmol/l of L-phenylalanine at the final concentration, whereas the activity of SI-ALP was inhibited by 95%, indicating the degree of inhibition for SI-ALP was higher than liver and bone type ALPs. When we tested the recombinant ALP of human liver type, “TraceCalib, Kanto Chemical Co., Inc., Tokyo” which is a calibrator for the transferable method, similar results to those of liver and bone type ALPs were obtained. These results indicate that the inhibiting assay method using L-phenylalanine is useful for evaluating SI-ALP activity, which mostly corresponded to the activities inhibited by the presence of L-phenylalanine out of the total ALP activity of an assay sample. We believe that our method is convenient for measuring the catalytic activity of SI-ALP and excellent regarding its quantitativeness, ease of manipulation, and general usefulness.

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The ALP activities measured by the JSCC transferable method were significantly different depending on the ABO blood groups of the specimen used, between A·B types and B·O types (P<0.001). On the contrary, when a multiple comparison test was performed using the activities obtained by a modified JSCC transferable method in the presence of L-phenylalanine, no significant difference was observed regardless of the ABO blood groups.
We determ ined that the value inhibited by the assay using L-phenylalanine was small intestine-type ALP (SI-ALP) activity.
Maximu m likelihood estimation was applied for determination of the reference intervals not only in the total ALP activities of the JSCC transferable method, but also in the SI-ALP activities. The reference intervals for the total ALP activity were 110 to 340U/l (median: 201U/l) for A and AB types, and 153 to 379U/l(median: 239U/l) for B and O types. The reference intervals of SI-ALP activity were 1 to 16 U/l (median: 4U/l) for A and AB types, and 2 to 73 U/l ( median: 21U/l) for B and O types.
There was a linear regression line (y=1.003x-1.4, r=0.998, r; correlation coefficient) for the ALP activities between the IFCC transferable method (x) and the modified JSCC transferable conversion method (y). Thus, as long as a suitable calibrator is available, activity in the converted method was compatible with the IFCC method's value. The inhibition assay presented in this paper is a useful tool for obtaining the activity of the IFCC transferable method.

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We studied the utility of small intestine-type ALP (SI-ALP) activity, which was measured based on an inhibition assay using L-phenylalanine, as one of the markers for diagnostic criteria in liver diseases in comparison with other markers. Chronic liver diseases were divided into the following 4 groups: group L light liver fibrosis (fatty liver, alcoholic liver diseases, etc.). group 2: chronic hepatitis (hepatitis B, C, and nonB, nonC), group 3: liver cirrhosis including liver-cell carcinoma complications and group 4: other particular chronic liver diseases (PBC, IPH, NASH, etc.). Although many markers were found to discriminate between group 2 and 3 using a nonparametric multiple comparison test, the markers to distinguish between group 1 and 2 were only the SI-ALP (P<0.05) and the ratio of SI-ALP against γ-GT (P<0.005). In addition, the ROC analysis for discrimination between group 1 and 2 showed that the most efficient discrimination was achieved by taking the ratio of SI-ALP against γ-GT, followed by γ-GT and SI-ALP. Thus, the SI-ALP is a useful marker for diagnostic criteria on the occurrence of fibrosis in liver disease, and the diagnostic criteria are certainly improved by taking its ratio to γ-GT.

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Practicality of the guideline “Protocols for determination of limiits of detection and limits of quantitation (EP17)” issued by NCCLS was evaluated both theoretically and experimentally by the JSCC Committee on Quality Management, In this report ISO 11843 document describing the concept of detection limits was reviewed and the NCCLS guideline was interpreted and summarized. The following two modifications were made to the guideline based on results of the evaluation: (1) methods for selection and preparation of blank specimens are presented and (2) use of so-called precision profile, which is constructed from replicate measurement of multiple clinical specimens, was proposed as a practical way of determining limits of quantitation.

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