Micro-determination of serotonin and histamine was accomplished by means of high-speed liquid chromatography and automated fluorometric analysis using 0- phthaldialdehyde. 0.5 ng of serotonin and 0.1 ng of histamine can be easily deter-mined by the methods described here. For the analysis of urine of healthy human subject, any pre-purification was not carried out to measure serotonin, but in the histamine analysis, extraction by a column of weak cation exchange resin was necessary before injection to the high-speed liquid chromatograph. It was found that diurnal rhythm of urinary serotonin was statistically significant (p<0.01) in healthy human subject, and that the night level of serotonin was slightly higher than the daytime level.
Intratracheal inoculation of 40 mg of haematite dust did not cause any marked change, histological or biochemical, in guinea pig lungs. Presence of the dust in decreasing amounts with lapse of time by analytical methods and its demonstra-tion in the lung and lymph nodes by histopathological techniques point the exis-tence of an efficient clearance mechanism in vivo in response to haematite dust exposure.
Guinea pigs inoculated intratracheally with Candida albicans, a facultative pathogen of upper respiratory tract of miners, and iron ore dust did not produce extensive pulmonary fibrosis and the reaction chiefly consisted of thickened inter-alveolar septa at the termination of experiment (180 days). The poor fibrogenic response observed has been suggested to be the inhibitory effect of possibly the soluble fraction of iron ore on the growth of C. albicans.
The amounts of penetration of 5 chlorinated solvents through excised rat skin were quantitatively determined by using a multiple phase equilibration method without using chlorinated solvents labelled with radioisotope. The results were compared with those obtained from an in vivo method as previously reported. The penetration rates obtained from the present in vitro method correlated well with those obtained from the in vivo method. Namely, the log-log plot of the in vitro data versus the in vivo data showed a linear relationship, although quantitative agreement between the two sets of data was less than perfect. This systematic comparison of in vitro with in vivo data has shown that the in vitro method for measuring the penetration rate of the chlorinated solvents can reflect the living state.
Though primary irritancy was not indicated for fungicides benomyl and thiophanate-methyl, extreme potency of contact sensitization was estimated only for benomyl from the guinea pig maximization test. Allergenicity ratings of sulfuric compounds, lime sulfur mixture and wettable sulfur powder, and a portion of chemical structure for benomyl, i.e., n-butyl carbamate were noted to be moderate, but such degree of allergenicity was not observed in cases of thiophanate-methyl and one of their metabolite MBC. Contact sensitization for thiophanate-methyl, however, seemed to be potentiate slightly when used with a sulfuric compound. The cross sensitization between benomyl and thiophanate-methyl was not revealed.
In using an improved fixation, light and electronmicroscopic autoradiography were done on the mouse kidney after 5 hr of intraperitoneal injection of 200μCi of 109CdCl2. The kidney incorporated 5.1% of the administered radiocadmium. The radiocadmium was evidently higher in the cortex than in the medulla and increased from the juxtamedullary zone to the capsular surface in cortex. There was a wide variety of grain density among proximal tubules, which were always higher as compared with distal tubules, glomeruli, blood vessels and connective tissue. Electronmicroscopic autoradiography gave also almost the same results. As those findings were in rather good agreement with the hitherto reported results on the frozen-dried section, it was suggested that the improved fixation could be useful alternative of the latter method. It was also interesting to note that the highest "relative density", when expressed as grain numbers per unit area of an organella, was obtained in the basement membrane of the proximal and distal tubules.
A procedure of quantitative chemical analysis on a crysotile fiber under electron microscopy was developed, and was successfully adopted to a study on its changing chemical composition in situ during its long lasting residence in the rat lung. Lungs were obtained from the rats, which were sacrificed at 4 and 28 months after an intratracheal insuffiation of 10 mg of the crysotile. Routine paraffin sec-tions from those lungs were treated by means of carbon extraction technique and were submitted to analytical electron microscopy. Every single fiber identified under transmission EM was determined for the chemical composition by an simultaneous application of the X-ray microanalysis of energy dispersing type. It was found that magnesium ion leached far faster than silica out of crysotile fibril during their residence in the lung tissue. It was also suggested that, in calculating the ratio of magnesium content to silica in the single fiber, rough estimation may also be possible on its past retention period in the lung tissue. Preliminary determinations on the experimentally degradated crysotile in the test tube were also described. Results obtained from the X-ray Fluorescence Spec-trometry and the X-ray microanalysis of energy dispersive type were compared and discussed on possible application of the latter method to the crysotile fiber in vivo.