Showing papers by "Hiroshima University published in 1972"

Electrophysiological studies on cerebello-cerebral projections in the cat

Abstract: 1. Cerebello-cerebral projections were electrophysiologically investigated in cats under light Nembutal anaesthesia. Marked responses were produced by stimulation of the interpositus and the lateral nucleus of the cerebellum not only in the pericruciate but also in the suprasylvian cortical areas, both areas being contralateral to the cerebellar nuclei stimulated. Medial nucleus stimulation set up little or no response in the cerebral cortex. 2. The previous electrophysiological study on thalamo-cortical (T-C) projections showed two different kinds of responses in the cortex due presumably to two different T-C projection systems, i. e., deep and superficial T-C responses (see Sasaki et al., 1970). According to laminar field potential analysis, the response in the pericruciate area is characterized by a deep T-C response which is often followed by a superficial T-C response, whereas the response in the parietal cortex consists of a pure superficial T-C response. Intracellular potential changes in cortical neurones elicited by cerebellar nucleus stimulation were consistent with the results of laminar field potential analysis. 3. Comparison between laminar field potentials in the same cortex produced by thalamic and cerebellar nucleus stimulation suggests that the response in the pericruciate cortex is mediated by the ventral lateral nucleus and that the response in the parietal cortex is relayed by the ventral anterior nucleus of the thalamus.

On the cerebello-thalamo-cerebral pathway for the parietal cortex.

Abstract: 1. The cerebello-thalamo-cerebral projection system mediating the cerebellar-induced “superficial thalamo-cortical (T-C) response” (the basic type of the so-called recruiting response) to the anterior part of the middle suprasylvian gyrus was investigated electrophysiologically. Responses of thalamic neurones to stimulation of the cerebral cortex and the cerebellar nucleus (medial, interpositus and lateral) were recorded by microelectrodes. 2. In the anterior portions of the ventral thalamic nuclear complex, presumably in and/or around the ventral anterior (VA) nucleus, there were found neurones responding antidromically to stimulation of the suprasylvian cortex and orthodromically to that of the interpositus and the lateral nucleus of the cerebellum. They were called P neurones. The neurones responding antidromically to stimulation of the anterior sigmoid cortex and orthodromically to that of the cerebellar nuclei located mostly caudo ventrolateral to the place of P neurones, presumably in and/or around the ventral lateral (VL) nucleus. These were called F neurones. 3. The cerebellar excitation of P neurones was estimated on its latency to be monosynaptic and was usually followed by an inhibition lasting for more than 100 msec. Large unitary EPSPs were sometimes noted in P neurones on cerebellar stimulation as well as spontaneously. It was concluded that P neurones constitute the direct T-C projection system mediating the superficial T-C response (e. g., recruiting response) to the parietal cortex.

Hot Universe, Cosmic Rays of Ultrahigh Energy and Absolute Reference System

Abstract: Shortly after the discovery of the cosmic thermal radiation with temperature of ,_,3•K,ll it was noted that such radiation would have a strong attenuation effect on cosmic rays with energies exceeding 1020 eV.2> Although the average energy of these thermal photons is as small as IQ8eV, they interact with the cosmic rays to produce 7!'-mesons, because the thermal photons look like r-rays with energies of ,_,200 MeV in the rest system of the cosmic rays. As the mesons resulting from the photoproduction carry off a significant fraction of the cosmicray energy, the attenuation mean-free-path of the cosmic rays with energies above 1020eV becomes as small as 108 ·0,_,107•8 parsec. 8> On the other hand, analysis of an extremely large air shower have revealed that the energy spectrum of cosmic rays extends smoothly beyond 1020e V, and moreover, cosmic rays with energies of 4.1021 e V have been observed by Suga et aU> Therefore, the non-existence of the expected cutoff in the vicinity of 1020e V offers a critical discrepancy between the theory and the observation. There might be astronomical ways to get rid of this discrepancy: One is to assume a non-universal existence of the isotropic thermal radiation and another is to assume a local origin of the ultrahigh energy cosmic rays. However these ways are not so promising from the following arguments. About the first way, there is no reasonable mechanism of generating such radiation in our Galaxy5> and, further, the hot universe model which predicts the universal existence has other powerful assertions such as an explanation of the helium abundance and a theory of galaxy formation.6> About the second way, some authors have proposed the Galactic origin such as the pulsar origin or the explosive origin in the Galactic nuclei. 7> However these theories necessarily meet very great difficulties to explain the mechanism of acceleration in a compact region and the arrival directions. There might be other way to assume exotic primaries like neutrinos or dusts.6> We now propose a different way to get rid of this discrepancy. Usually it is assumed that all inertial systems are totally equivalent for the performance of all physical experiments, i.e., the assumption of the relativity principle. However we have no experimental evidence to verify this principle for the reference systems moving with Lorentz factors of above r\"\"l05 relative to our laboratory system on the earth. In the above discussion on the attenuation of cosmic rays, we have assumed that the conventional relativity principle is .correct even for the reference systems of r::::::1011 • Therefore we must notice that the attenuation of cosmic rays is not a consequence of experiment.9> Inversely, if the attenuation were really found experimentally, it might be a remarkable evidence to expand the applicable realm of the relativity principle.

In vivo Formation of Phosphopeptide with Calcium-binding Property in the Small Intestinal Tract of the Rat Fed on Casein

Abstract: A partially purified phosphopeptide fraction with low N/P ratio has been obtained from the small intestinal contents of rats, which was collected at the first one hour after 1.5 hr spaced-feeding of the diet containing 20% casein.After precipitation of protein with trichloroacetic acid, acid-soluble fraction was chromatographed on the column of Sephadex G-25.A fraction containing large peptide(s) having the N/P atomic ratio of about 7 to 9 and free from lower molecular substances was rechromatographed with Sephadex G-50.This fraction, amounted nearly 30% of the total non-protein nitrogen of the intestinal contents, showed high calcium-binding activity as determined with Chelex-100.These results suggest a special role of phosphopeptide stage on the stimulating calcium absorption in the intestinal tract during the digestion of casein.

On the fine structure of alteration of the adrenal cortex in hypophysectomized rats.

Abstract: The adrenal cortex of normal and hypophysectomized rats was observed by electron microscopy 5–90 days after the operation and, chiefly, the degeneration mechanism of the cortical tissue was discussed. In normal rats mitochondrial inner structures are generally tubular in shape in glomerulosa cells, vesicular (and tubulo-vesicular) in fasciculate cells and tubulo-vesicular (and vesicular) in reticularis cells. Some mitochondria in a few glomerulosa cells show long straight tubular crests in normal as well as hypophysectomized rats. Usually lipid droplets in normal glomerulosa, fasciculate and reticularis cells are surrounded by elements of smooth endoplasmic reticulum, which are very closely associated with mitochondria. About 10–25 days after hypophysectomy, most mitochondria in fasciculate and reticularis cells show tubular crests, and numerous electron lucent lipid droplets are accumulated in these cells. These droplets occupy most parts of the cytoplasm and are sometimes in contact with one another or with mitochondria. The elements of smooth endoplasmic reticulum and Golgi apparatus are markedly reduced in number and size. About 10–90 days after the hypophysectomy, the degenerative cortical cells containing irregularly shaped nuclei, heterogeneously dense bodies in various sizes, and a large number of electron lucent lipid droplets are seen. The author speculates that most fasciculate and reticularis cells degenerate because of a disorder in the lipid metabolism, since ACTH release, which is necessary for synthesis of corticosteroid hormones from cholesterol, is absent in hypophysectomy. The fatty degeneration of the fasciculate and reticularis cells is considered to be a main cause for attenuation of the cortical tissue. Sometimes atrophied cortical cells without lipid droplets are also found 60–90 days after hypophysectomy.

Electrical and Mechanical Activities in the Radula Protractor of a Mollusc, Rapana thomasiana

Abstract: 1. The radula protractor ofRapana thomasiana consists of obliquely striated muscle fibers containing thick and thin filaments, and each fiber is surrounded by wide interfiber spaces. 2. The electrical response to indirect stimulation recorded by a sucrose gap method is the same in pattern with that obtained intracellularly. This suggests that all muscle fibers receive multiple innervation and respond to single nerve impulse synchronously. 3. The amplitude of excitatory junctional potential gradually increases with increase in stimulus intensity or duration. All-or-nothing type spike is not recorded with a single stimulation. 4. By repetitive stimulations, the facilitation and the summation of electrical and mechanical responses were produced. In some preparations a few spike-like potentials were evoked during stimulations. 5. The potentiation of electrical and mechanical responses to repetitive stimuli reaches the maximum at a frequency of 50/sec. 6. Effects of drugs suggest that the neuromuscular transmission is cholinergic.

Primordial irregularities in the early universe.

Abstract: In the early universe, there is an "anti-Newtonian stage" when the dimension of an irregularity exceeds the horizon ct, far before the decoupling epoch. In this paper the evolution of an irregularity at this stage is clarified, in which general relativistic non-linearity plays an essential role. It is concluded that the explosion time (or the singular point) of the irregularity depends sensitively on the energy density within it (e.g., the rotational energy density), that the existence of primordial random motions at the later stage leads necessarily to the concept of a "space-time-curvature turbulence" at an extremely early stage when random explosions are raised and that the irregularity in the neighbourhood of its singular point is considerably anisotropic. The significance of this conclusions in the formation of nuclear elements at the early stage is also discussed.

Effect of chemical structures of acridine and triphenylmethane dyes on the induced optical activity of DNA-dye complexes.

Abstract: Fifteen symmetrically substituted acridine dyes, all of which are interrelated by their chemical structures, each belonging to a C2v symmetry, and three triphenylmethane dyes with amino or dimethylamino substituents are utilized to study necessary conditions for the appearance of extrinsic Cotton effects upon their binding to native and heat-denatured deoxyribonucleic acid (DNA). Three different kinds of the DNA–dye complexes, i.e., (1) dye added to native DNA, (2) heat-denatured DNA–dye complex, and (3) dye added to preheated DNA, were examined for each dye at a fixed P/D value of about 4. Optical activity was always observed for the compelexes of type (1) in each absorption band of the dyes in the visible and near-ultraviolet region. Two exceptions are 9-acetamido- and 9-hydroxyacridine, both being nonionic in aqueous solution at a pH range of 6. Acridinium chloride was unable to exhibit any definite extrinsic Cotton effect for complexes (2) and (3). Thus, the monocationic form of a dye due to the protonation or quaternization of the ring nitrogen in acridines or exonuclear amino nitrogen in triphenylmethane dyes is concluded to be an essential factor for extrinsic Cotton effect to appear. Changes in the absorption spectra upon complex formation are also related to the structure of dyes. Hypochromism and bathochromism are associated with the induced optical activity in all cases in the presence of native and denatured DNA.

Heterogeneity of Peroxidase Related to Antibacterial Activity in Human Parotid Saliva

Abstract: The peroxidase that is related to the thiocyanate-peroxidase-hydrogen peroxide antibacterial system in human parotid saliva was separated into three subfractions by diethylaminoethanol (DEAE)-cellulose column chromatography. Heterogeneity was confirmed by isoelectric focusing. Three subfractions contributed to the inhibition of the growth of Lactobacillus casei ATCC 7469.

A Possible Interpretation of the New Event in the Cosmic Ray Experiment

Abstract: In a previous paper we have analysed a new event observed by Niu and others in cosmic ray experiments, and have been able to present a reasonable interpretation of it on the basis of the new (modified) Nagoya model for urbaryons. Anticipating the accumulation of such new events, we shall give a further study in this paper, especially about the details of weak decay processes which were not fully developed in the previous work.

Surface view of the frog vestibular organ with the scanning electron microscope.

Abstract: The characteristic surface structure of the epithelial layer of the statoconia, the otolithic membrane, the macula statistica and the semicircular ampulla in frog was studied with scanning electron microscope, paying particular attention to the structure of the otolithic membrane, the relationship of the reticular structure and sensory hairs, the form of sensory hair, and the arrangement of sensory hairs in the sensory region of the semicircular ampulla, the detailed structure of which have not successfully been observed by electron or light microscopic methods. Further, the free surface of the transitional zone, the planum semilunatum and the gelatinous portion of the ampulla was demonstrated. New findings on the structure of the gelatinous portion are also described.

Leukemia and thyroid carcinoma found among A-bomb survivors in Hiroshima.

Abstract: It is a well-known fact that various neoplasms can be induced by ionizing radiation. In humans, leukemia, and carcinomas of the skin, lung, thyroid gland, etc., have been reported among persons exposed to either total body or local irradiation, mostly for diagnostic and therapeutic purposes with X-rays. On the other hand, the final conclusion has not been reached yet, whether certain types of neoplasm were induced significantly by the atomic bomb explosions at Hiroshima and Nagasaki. But at present it is considered to be almost certain that leukemia and thyroid carcinoma were induced in high incidences by atomic bomb radiation. Induction of malignant lymphoma and carcinomas of the breast, ovary and lungs by atomic bomb irradiation is inconclusive and accepted by some and denied by others. For these reasons, presentation of data and discussion on this occasion will be limited to leukemia and thyroid carcinoma.

Enhancement of Sensitivity for Selenium Determination in Atomic Absorption Spectrophotometry by Introducting Hydrogen Selenide into an Argon-Hydrogen Flame

Abstract: The sensitivity for selenium determination with atomic absorption spectrophotometry is enhanced to a large extent by introducing hydrogen selenide gas into an argon-hydrogen flame. As a reducing agent, zinc granular and stannous chloride is successfully used for quantitative and rapid productions of hydrogen selenide from selenium(IV) solution. The sensitivity for 1 % absorption of the signal is estimated to be about 0.02 ppm of selenium.

Anatomical observations on the high frequency callus formation from anther culture of chrysanthemum

Abstract: Calluses were induced with 100% rate from anthers of 8 species and 2 varieties of diploid and polyploid Chrysanthemum species.Most of the calluses were found to be derived from the cells of the connective tissue between the thecae of the anthers. Within 40 days from cultivation, these calluses differentiated roots, and numerous shoots were differentiated within 40 days after transplanting to the medium without auxin hormones.The induced plants examined in some genetic strains showed the same chromosome number as the respective mother strains.

Peptide analyses of a protein component, 50-8, of 50s ribosomal subunit from erythromycin resistant mutants of Escherichia coli and Escherichia freundii

Abstract: Chromatographic analyses on a Dowex 50x8 column of tryptic digests of the mutationally altered 50-8 protein component from several erythromycin resistant (ery r) mutants of Escherichia coli and Escherichia freundii have been performed. It was found that (1) the difference in the elution profile of the altered components detected with carboxymethyl cellulose column chromatography reflects the difference in their amino acid sequence, (2) the structural change(s) of the 50-8 protein from three E. coli ery r mutants examined seems to exist only in the same single peptide fragment and (3) the primary structure of the 50-8(R) protein of E. freundii (ery s: wild type) differs from that of E. coli Q13 (ery s) and the structural change in 50-8(R) component of E. freundii caused by the ery r mutation was found to take place in different peptide fragments from that in which the mutational change of the E. coli 50-8 component occurred.

Design of a balanced multiple-valued filing scheme of order two based on cyclically generated spread in finite projective geometry

Abstract: The balanced multiple-valued filing scheme was defined by Ghosh and Abraham (1968) . They constructed there two types of balanced multiple-valued filing scheme of order two. One scheme was obtained by deleting a spread generated by parallel lines in a finite affine geometry EG ( t, s ) and the other was obtained by deleting a partial spread generated by all the lines in a finite projective geometry PG ( t, s ) which have one particular point in common. The idea of these methods of construction was generalized by Koch (1967) . In this paper, we shall give a new type of balanced multiple-valued filing scheme of order two constructed by deleting a cyclically generated spread in a finite t -dimensional projective geometry PG ( t, s ) where t + 1 is not prime. Since the spread identified with the set of attributes and the lines identified with the buckets can be generated cyclically in multiplicative representation of the points in PG(t, s) , the proposed scheme can be implemented easily.

Potential in the Canonical Formalism of Gravity

Abstract: We attempt to derive the gravitational potential from the canonical formalism viewpoint of the gravitational :field coupled with matter. The two-body potential in an arbitrary co· ordinate frame (i.e., gauge) is obtained by solving constraint equations. It is shown, by mak­ ing a transformation of the time coordinate, that the potential coincides with.Hiida's obtained with the aid of the "diagrammatic" quantization. A simple equation to get the static potential to any order is presented. Explicit forms of the static potential are given up to the :live-body potential. From the form of potential it is immediately seen that there exists a relation be­ tween twq-body and many-body static potentials.

Slow conduction in the atrioventricular node of the cat: A possible explanation

Abstract: Nachweis, dass bei Erhohung des Membranpotentials im AV-Knoten der Katze eine raschere Erregungsausbreitung erzielt werden kann.

Enhancement of Sensitivity for Antimony Determination in Atomic Absorption Spectrophotometry by Introducing Stibine into an Argon-Hydrogen Flame

Abstract: The sensitivity of antimony determination with atomic absorption spectrophotometry is enhanced to a large extent by introducing stibine gas into an argon-hydrogen flame. As a reducing agent, zinc tablet made from the zinc powder paste with water is successfully used for quantitative and rapid productions of stibine from antimony (III) solution. The sensitivity for 1% absorption of the signal is estimated to be about 0.004 ppm of antimony.