Biomedical subjects
Publications and source records attributed to T Miyoshi.
The synthesis of hypoxanthine, 2-chlorohypoxanthine, and 2-methylhypoxanthine arabinoside by an enzymatic transarabinosylation and their chemical conversion to biologically interesting purine arabinosides are described. Some of the synthesized compounds were tested for the inhibition of DNA synthesis in cultured tumor cells.
The role of direction of linear acceleration in stimulation of the otolith organ, which leads to alteration of autonomic activities in the form of inhibition of gastric motility, has not been fully studied. With a view to elucidating this problem, we placed healthy adult rabbits unanesthetized and unrestrained in individual cages, and subjected them to the three different linear acclerations to study changes in gastric EMG. As a result, the forward-and-backward movement was found to inhibit the EMG activity most potently, and was followed in decreasing order by side-to-side movement and up-and-down movement. These findings, when viewed from the standpoint of the accepted concept that optimum stimulation to the otolith organ constitutes the shearing force, account well for the supposition that forward-and-backward movement stimulates both the sacculi and utriculi, while up-and-down movement stimulates the sacculi alone.
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The influence of repetitive applications of optokinetic and vestibular stimuli upon the vestibulospinal responses, measured by the stepping test, was investigated both in an optokinetic training and vestibular habituation test series. Repeated applications of optokinetic and vestibular stimuli modified the rotation angles of the stepping test, i.e. vestibulospinal responses, resulting in a response decline of rotation angles which was still present after 1 month.
Adsorption of hydrogen sulfide, methanethiol, methyl sulfide, trimethylamine, and ammonia on thirteen kinds of adsorbents (5 kinds of silicate, 4 kinds of activated carbon, and 4 kinds of zeolite) was measured by gravimetry, at 30 degrees C and 50 Torr, using an adsorption apparatus with a spring balance in order to find the most suitable adsorbent for the removal of these gases by dry process. The relations between the amount of these gases adsorbed (mmol/cm2) on the adsorbent and the surface properties or the porous structure were examined to clarify the mechanism of adsorption of these gases on them through surface pH, pore size distribution, and area of an adsorbed particle of these gases. Among the thirteen adsorbents, the activated carbon Nos. 6 and 7 were the most suitable adsorbent for methanethiol, methyl sulfide, and trimethylamine whose area of an adsobed particle (wrho) was larger than about 17 A2, and zeolite Nos. 12 and 13 were most suitable for removal of hydrogen sulfide and ammonia (wrho less than about 17A2). The amount of these gases adsorbed (mmol/cm2) on these adsorbents was mainly determined by their porous structure rather than by their surface properties.
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The relationship between visual line and target in optokinetic nystagmus was studied by means of the eye-mark camera and film-motion analyser. The eye-mark carmera provides a series of pictures in which the visual field and fixation point of the subject overlap. The visual line is observed as a spot of light on the film. Accurate analysis of films with the analyser produces detailed information on the calibration and movement of the target and visual line. Comparison with the ENG, taken simultaneously, indicates the adequate sensitivity and accuracy of this method. There are five types of relationship between visual line and target in optokinetic nystagmus. In type I, the visual line coincides with the target in the slow component of nystagmus. This type agrees with the conventional considerationation of the slow component of nstagmus. Type II indicates the existence of some servo-mechanism in the target catching action of the eye. In type III, there are three kinds of slow components, one chincides with one edge of the target, one with the other edge and another fixes on some point between the two and follows it. The velocities of these three are equal to that of the target. In type IV the visual line gradually lags behind the target, but the rhythm of the nystagmus coincides with that of the stimulation. In type V, dysrhythmic nystagmus develops and the visual line often jumps over several targets without fixation.
Microscopic examination of cultures of Escherichia coli exposed to bicyclomycin revelaed elongated or spheroplast-like cells. At the lethal level, bicyclomycin was shown to inhibit the synthesis of RNA and protein in the growing cells of E. coli 15 THU, whereas DNA and lipid synthesis were not significantly affected. However, the antibiotic did not block RNA and protein synthesis in vitro. Bicyclomycin was observed to inhibit the synthesis of envelope proteins more markedly than that of cytoplasmic proteins. The synthesis of two major envelope proteins was more sensetive to bicyclomycin than that of the other envelope proteins. One (peak I), which was inhibited to the greatest extent, seemed to be identical with a bound form of lipoprotein, and the other (peak V) with a free form of lipoprotein. Bicyclomycin exhibited inhibitory effects on the exclusive biosynthesis of the lipoprotein in histidine-starved cells of E. coli 15 THU. The biosynthesis of the bound form of lipoprotein was more profoundly inhibited by bicyclomycin than that of the free form. These results indicate that the primary action of bicyclomycin may be due to the interference with the biosynthesis of lipoprotein, and its assembly to peptidoglycan.
The present study was designed to secure some fundamental informations on the adsorption removal of ammonia gas by the static method. In order to find out the suitable activated carbons for the adsorption removal of ammonia gas, amounts of ammonia gas adsorbed on twelve kinds of activated carbons were measured at 30 degrees C and up to 70,000 ppm of ammonia gas. The relations between the amounts of ammonia gas adsorbed on the activated carbons and the physical properties of them were discussed through the results of specific surface area, pore volume, mean pore radius, scanning electron micrograph, pH, and amount of base. The results were as follows: 1) Among the twelve kinds of activated carbons, the activated carbons No. 2, No. 3, and No. 6 adsorbed larger amount of ammonia gas than the others. 2) Adsorption of ammonia gas on the activated carbons seemed to be mainly physical as judged from the values of heat of adsorption. 3) The adsorption capacity of the used activated carbons can be recovered to the original capacity by some treatment. 4) The period to reach adsorption equilibrium was about 5 minutes. 5) It may be concluded that adsorption of ammonia gas on the activated carbons was decided mainly by the surface properties (pH and amount of base) of the activated carbons rather than their porous structures.
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