Development of an ultra-high sensitive photon counting system and its application to biomedical measurements

The sensitivity of the photon counting method for the detection of extra-weak optical intensity was improved on the introduction of the enhanced single photoelectron counting technique incorporated with a selected photomultiplier operated under optimum conditions. With this ultra-high sensitive photon counting system it has been possible to measure the difference between the luminescence of the blood of healthy and diseased human subjects (both have extremely weak values).     

Quality control of radioimmunoassay by bivariate analysis

Automatic calculation of control charts for precision and accuracy of radioimmunoassay was reported by Faure, et al. Duplicate control samples independently measured was assumed to have a bivariate normal distribution. In this case they assumed that the correlation coefficient between each value of the pairs of control samples is zero. Our experience using this method revealed that a considerable number of assayed samples distributed outside the calculated control limits in case of "accuracy control". It was considered that this happened because in radioimmunoassay the between-assays precision is usually larger than the within-an-assay precision and there is a significant correlation between values of duplicates. We also found equal probability density did not make a true circle but a long circle. Therefore in the present paper we proposed for control charts of radioimmunoassay an equal probability long circle calculated by bivariate analysis of Mahalanobis' generalized distance. It was found that a Mahalanobis' long circle could explain the density distribution of radioimmunoassay with a reasonable percent of samples outside the calculated control limits. What happened here can be interpreted by a large between-assays variability shown by some commercial kits. This automatic calculation method could be applied not only for quality control but also for evaluation and comparison of radioimmunoassay system or commercial kits. Control survey could also be analyzed by such a method.     

Novel phenolic glycoside dimer and trimer from the whole herb of Pyrola rotundifolia

From the water-soluble constituents of the whole herb of Pyrola rotundifolia (Pyrolaceae), one novel phenolic glycoside dimer, pyrolaside A (1), and one novel phenolic glycoside trimer, pyrolaside B (2), together with two known phenolic glycosides homoarbutin (3) and isohomoarbutin (4), were isolated. The structures were elucidated by spectroscopic analysis and confirmed with chemical degradation. In vitro tests for antimicrobial activity showed pyrolaside B (2) to possess significant activity against two Gram-positive organisms, Staphylococcus aureus and Micrococcus luteus.     

Hydrogen production by conversion of methane over nickel-supported USY-type zeolite catalysts

Hydrogen production by conversion of methane over Ni-supported zeolite catalysts was investigated, and Ni-supported USY-type zeolite (Si/Al₂ = 14.0, 360) was found to have longer catalytic lifetime than Ni-supported silica (Cab-O-Sil) catalyst, which had been reported to have the longest catalytic lifetime for this reaction.     

Effects of aging and oxidation on positronium formation in polyethylenes

Positron annihilation lifetimes (PAL) have been measured for polythylenes (PEs) under differenr conditions of heat treatment. It is shown that the intensity, I₃, of the long-lived component of positronium (Ps) shows hystereses between the heating and cooling processes due to aging effect. It is also shown that about half of Ps observed at low temperatures below the glass transition is inhibited after the sample is heat-treated above the melting point in the atmosphere containing oxygen. It is suggested that carbonyl groups (C=0) formed by thermal oxidation can inhibit Ps formation through trapping the precursors of Ps, e⁺ and/or e^-.     

Renal blood volume vs. glomerular filtration rate: evaluation with C15O and 88Ga-ethylenediaminetetraacetic acid (EDTA) study

68Ga-EDTA (ethylenediaminetetraacetic acid) is simply and economically obtained without a cyclotron. We used renal blood volume (RBV) values obtained by C15O studies for blood activity subtraction on renal time activity curves using a positron emission tomography for the determination of the glomerular filtration rate (GFR) by intravenous 68Ga-EDTA administration. Positive correlation was revealed between the GFR and RBV values, where the ratio of blood activity in whole renal activity increased relatively as GFR value decreased. The estimation using a correction equation derived from the correlation curve was possible without a C15O study.     

Determination of the major urinary metabolite of diphenylhydantoin by high-performance liquid chromatography

A method is described for the determination of 5-(p-hydroxyphenyl)-5-phenylhydantoin (p-HPPH), a major urinary metabolite of 5,5-diphenylhydantoin (DPH) in man. The assay involves acid hydrolysis, extraction and high-performance liquid chromatographic analysis using a column comprised of small-particle silica gel. This procedure has been used to determine p-HPPH levels in urine from healthy volunteers who ingested 400 mg of sodium DPH. The p-HPPH concentration was found to range from 10 to 300 μg/ml. The minimum detectable concentration of urinary p-HPPH was 1 μg/ml.