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Biomedical subjects

M Matumoto

Publications and source records attributed to M Matumoto.

At least 91 records · Page 5Linked to original sources
PubMed1980

[Double polarized excitable system of the nerve fiber and its action potential (author's transl)].

An excitable tissue, namely a nerve or muscle fiber was regarded as an excitable system consisted of "field of excitation" and "active element" and the nerve fiber especially as a double polarized excitable system, because its equivalent circuit in resting state was constituted of two polarized layers. On the above view point, the author stated the action potential of the double polarized excitable system as the following. In the double polarized excitable system, the inner layer is polarized Em by itself, while the outer layer surrounding out side the inner layer is polarized Eo due to discharge current of Em. Then the cell potential (resting potential) Ec, the potential difference between in and out side of the system, is represented as Ec=Em-Eo. Excitation is referred to the temporary change of the equivalent circuit of resting state to that of excited state by temporary state by temporary reduce of resistance of inner layer nearly to zero, resulting temporary decrease of Em and change of Ec (action potential). Through the event, decrease of resistance of the inner layer is the root of the process, so was named active element, and the other electric constitution as field of excitation. Theoretically calculated and experimentally recorded action potential of this system showed every course of the action potential of the nerve fiber known already, including overshoot or undershoot (positive after potential).

Action Potentials↗
PubMed1977

Polyadenylate in the virion RNA of mouse hepatitis virus.

Mouse hepatitis (MH) virus was grown in SR-CDF1-DBT, a mouse cell line, and purified by ammonium sulfate precipitation and by density gradient centrifugation. Extraction of RNA from purified virions with 1% SDS and sedimentation analysis of the RNA revealed a major 50S component and two minor components. Treatment of virions with phenol/chloroform also produced the 50S component, although its yield was lower. MH virion RNA can bind to a poly(U)-fiberglass filter, indicating that MH virion RNA contains poly(A). A poly(A)-like fragment was isolated by digestion with ribonuclease A [EC 3.1.4.22] and T1 [EC 3.1.4.8] and by DEAE-Sephadex column chromatography. Analysis of the fragment for base composition showed it to be an adenine-rich material. Its chain length was about 90 nucleotides, as determined by ion-exchange chromatography and gel electrophoresis.

Cell Line↗
PubMed1977

[Semi-excitation in nerve and electric nerve model (ENM) (author's transl)].

The "semi-excitation" is an excitation (like phenomenon) found by the authors, first in ENM and then in nerve during observation of the action potential and impedance decrease associated with excitation. The phenomenon was further investigated in relation to the action potential and impedance decrease (for AC of 13 kHz) of the stimulated site on the sciatic nerve and ENM. The nature of the phenomenon was the following. 1. The configuration of the action potential and impedance decrease were almost the same as that of the (complete) excitation, but the durations of the potential change (plateau) and impedance decrease depended on entirely to the duration of stimulating current. 2. Submaximum amplitude of action potential and impedance decrease were graded by the intensity of the stimulating current, but the threshold of this excitation was found. 3. During or after the semi-excitation, absolute or relative refractory period was not found. 4. Both in nerve and ENM, transition from complete excitation to semi-excitation or vice versa was observed. 5. Semi-excitation was found to occurr in the state of reduced membrane potential of the nerve and ENM.

Action Potentials↗
PubMed1976

Epizootic congenital arthrogryposis-hydranencephaly syndrome in cattle: isolation of Akabane virus from affected fetuses.

Previous serolgoical studies strongly suggested Akabane virus to be the etiologic agent of epizootic abortion and congenital arthrogryposis-hydranencephaly in cattle, and this view was further corroborated in this study by the isolation of the virus from an aborted fetus in an epizootic of the disease and from a fetus extracted froma cow which was suggested by serologic tests to have a recent infection with the virus. The latter fetus had histological changes of encephalomyelitis and polymyositis, and specific antigens of Akabane virus was shown by the immunofluorescent technique in brain tissues as well as skeletal muscular tissues. The virus was recovered from various fetal tissues and fluids, and in relatively large amounts from brain, spinal cord, cerebral fluid, skeletal muscles and fetal placenta. The intracranial inoculation of suckling mice, 1-2 days of age, was the most sensitive system for Akabane virus isolation and HmLu-1, a continuous cell line from hamster lung, seemed almost as sensitive as suckling mice.

Abortion, Veterinary↗
PubMed1976

Mouse hepatitis virus (MHV-2). Plaque assay and propagation in mouse cell line DBT cells.

Various factor sinfluencing the plaque formation of mouse hepatitis virus (MHV-2) in DBT cell monolayers were studied and a practical method for plaque assay was developed. Infected DBT cells yielded high-titered virus and were a satisfactory source of complement-fixing viral antigen. The predominant cytopathic effect of MHV-2 in DBT cells was cell rounding and detachment, but no syncytial formation was observed. Fluorescent antibody staining revealed specific fluorescence only in the cytoplasm of infected DBT cells. In one-step growth experiment, newly formed virus was first recognized within 4-hr postinfection and showed subsequently a rapid exponential increase. Release of newly formed virus from the cell was rapid, and a continuous release lasted for a certain period of time. The average per-cell yield of active virus was estimated to be about 6-7 X 10(2) plaque-forming units.

Animals↗
PubMed1975

[On decrease in spike height of nerve action potential. A comparison between sciatic nerve and ENM (author's transl)].

Employing ENM and a sciatic nerve removed from bullfrog, configuration of decrease of spike under various experimental conditions was studied. The amplitude of the membrane potential change in excitation was also recorded simultaneously with the decrease of spike in ENM (electric nerve model). Both on the nerve and ENM, with decrease of the resting potential, the amplitude of the spike and the amplitude of the change of the membrane potential were decreased. On the nerve and ENM, the decrease in spike amplitudes was induced by an elevation of the niveau and by a lowering of the top. However, the amplitude of the change of membrane potential of ENM was reduced only from the base of the spike due to an elevation of the niveau, with the top remained at a constant level. These decreases of the spike amplitude and the change of the membrane potential in nerve were consistent with that the electric constitution was the same for nerve and ENM, which is the experimental equivalent circut of the nerve fiber devised by the authors.

Action Potentials↗