Biomedical subjects
Publications and source records attributed to H Takeuchi.
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Clinical features including changes in the peripheral nerve conduction were analzyed in 10 cases with ethambutol neuropathy. There were abnormalities in the visual field in seven and optic atrophy in five of 10 cases. Seven of 10 cases complained of numbness in the lower limbs. The age of onset and dose of ethambutol the patients continue to take after the occurrence of visual impairment were found to be important in determining the severity of neurological symptoms. A functional disturbance was more conspicuous in ethambutol neuropathy, particularly in the sensory system than in the motor system so far as the peripheral nerve conduction was serially examined. Some cases still had serious optic disturbances even about seven years after the onset of the disease and the presence of irreversible lesions was suspected.
The electrophysiological examination was made to clarify the effect of ethambutol on the peripheral nervous system in 39 patients at tuberculous sanatorium. Abnormalities in the sensory nerve action potential (toe-ankle) were observed in about 10 percent of the patients treated with ethambutol, and these patients were mostly elderly and/or received the high dose of ethambutol. The mixed nerve conduction velocity (ankle-knee) showed a significant decrease compared with healthy subjects. The conduction velocity tended to decrease in the high ethambutol dosage (200 gm or more) group compared with the low dosage (200 gm or less) group. The tendency for the conduction velocity to decrease was also observed in the 18 patients treated with isoniazid but the abnormalities were mild compared with the ethambutol.
1 The effects of derivatives of aromatic amino acids on the excitability of an identifiable giant neurone (TAN, tonically autoactive neurone) of the African giant snail (Achatina fulica Férussac) were examined. 2 The following substances had marked inhibitory effects on TAN using bath application: N-beta-phenylpropionyl-L-Tyr and N-beta-phenylpropionyl-L-Trp (critical concentration, 3 x 10(-7) M), N-beta-phenylpropionyl-L-Phe, N-cinnamoyl-DL-Trp and N-phenoxyacetyl-L-Trp (critical concentration, 10(-5) to 3 x 10(-5) M). However, N-beta-phenylpropionyl-D-Tyr and N-beta-phenylpropionyl tyramine had no effect. 3 Microdrop (150 micrometers in diameter) application of N-beta-phenylpropionyl-L-Tyr or N-beta-phenylpropionyl-l-trp containing about 100 pg resulted in marked inhibitory effects on TAN. The effect was observed in Ca2+-free, Mg2+-rich (24 mM) solution. Substitution of Cl- by acetate did not alter the response. This indicates that the two substances act directly on the TAN membrane and not via synaptic influences, and that the inhibition produced by the two substances is not due to the permeability increase of the TAN membrane to Cl-.
The influences of the replacement of sodium with lithium in the extracellular medium on the abnormal spike discharges, caused by two convulsants, metrazol and strychnine, of a giant neurone (TAN, tonically autoactive neurone) identified in the suboesophageal ganglia of the African giant snail (Achatina fulica Férussac) were examined. The slow oscillations of potential caused by metrazol disappeared after this replacement. On the other hand, the abnormal action potentials caused by strychnine, as well as the normal action potentials, still remained after the removal of sodium in the medium.
The effects of seven clavines, alkaloids of ergot, on the electrical activity of an identifiable giant neurone (TAN, tonically autoactive neurone) of the African giant snail were examined. All the substances examined, lysergine, agroclavine, elymoclavine, festuclavine, chanoclavine, rugulovasine A and rugulovasine B, at 2 X 10(-4) kg/l have no constant effect on TAN, indicating that they have no direct effect on this neurone. However, the substances examined, except for chanoclavine, in the same concentration occasionally caused the transient depression with an augmentation of trans-synaptic influences. This depression may be due to the trans-synaptic influences. The four substances examined, lysergine, agroclavine, elymoclavine and festuclavine, in the same concentration produced TAN abnormal spike discharges, doublet or triplet spikes.
The injection of acetylcholine receptor (AChR) purified from Narke electroplax japonica induced 'experimental autoimmune myasthenia gravis' (EAMG) in rabbits. Serial measurements of anti-AChR antibody titre using Narke AChR and rabbit AChR as antigen revealed that the intensity of myasthenia had a rather closer correlation with titre to Narke AChR than that to rabbit AChR. Antibody reacting to rabbit AChR was almost completely adsorbed out with torpedo receptor conjugated to agarose. Serum concentrations of antibody protein measured by affinity chromatography ranged from 54 to 896 microgram/ml serum and were well correlated with the intensity of myasthenia. The results suggested that in rabbits immunized with heterologous AChR the cross-reaction of anti-heterologous AChR antibody with rabbit AChR caused myasthenia rather than an immune response specific to rabbit AChR dose.
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Transabdominal esophageal mucosal transection with devascularization, a direct operation for varices, has been done upon 63 patients with marked esophageal varices that had bled or had a potential bleeding hazard. As of May 1978, 55 of the 63 patients are alive, and the over-all results appear to be satisfactory.
We tested the inhibitory power and urinary excretion of several derivatives of hippurohydroxamic acid, including some newly synthesized compounds. m-Methoxyhippurohydroxamic acid (UCD II) strongly inhibited urease activity and high urinary excretion after oral administration to rats. UCD II inhibited the alkalinization of infected urine in vitro and in vivo and prevented bladder stone formation when it was orally administered to rats with urinary tract infection caused by Proteus mirabilis. The clinical application of UCD II to the prevention of pathologic sequelae of urinary infection with urease-producing bacteria awaits evaluation of the safety of the compound.
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The effects of ergot alkaloids and their derivatives on the excitability of an identifiable giant neurone, TAN (tonically autoactive neurone), found in the suboesophageal ganglia of the African giant snail (Achatina fulica Férussac) were examined. Ergometrine and methylergometrine had the strongest inhibitory effects. The critical concentrations were 3 X 10(-5) approximately 10(-4) kg/l. The three hydrogenated ergot derivatives, 9, 10-dihydroergocristine, 9, 10-dihydroergocryptine and 9, 10-dihydroergocornine, had weaker inhibitory effects than those of ergometrine and methylergometrine. The other substances examined, including D-lysergic acid, D-lysergic acid amide, D-lysergic acid piperidinamide, had no effect. Some of the substances examined, for example, lysergine, agroclavine, elymoclavine, nicergoline, ergotamine, bromocriptine and lergotrile, at high concentrations occasionally caused transient inhibition immediately after their application. This inhibition may be due to the synaptic influences produced by the excitation of other neurones. Some of the substances examined, lysergine, agroclavine, elymoclavine, festuclavine, nicergoline and lergotrile, at high concentrations caused abnormal spike discharges of TAN such as doublet or triplet spikes.
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Eight tripeptides containing L-Phe-L-Tyr were synthesized, and their effects on the excitability of a giant neurone (tonically autoactive neurone, TAN), identified in the suboesophageal ganglion of an African giant snail (Achiatina fulica Férussac), were examined. Of these tripeptides, the following three showed a marked inhibitory effect: L-Glu-L-Phe-L-Tyr (most effective; critical concentration: 3 X 10(-6)--10(-5) M), Gly-L-Phe-L-Tyr and sarcosine-L-Phe-L-Tyr. The TAN inhibition caused by L-Glu-L-Phe-L-Tyr was not due to an increased membrane permeability to chloride ions.
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The influences of two water soluble contrast media, meglumine iothalamate and meglumine iocarmate, on the neuronal excitability and on the neuronal sensitivity to putative transmitters were examined in comparison with those of sucrose using two identifiable giant neurones of Achatina fulica Férussac (the TAN and the PON). A relatively low increase of osmotic pressure of the extracellular fluid, produced by the application of contrast media, reversed the Cl- dependent inhibition caused by a putative transmitter. The same increase of this osmotic pressure, however, did not influence the Cl- independent inhibition and the excitation of the neurone examined. The hyperpolarization of neuromembrane was caused by an increase of osmotic pressure of the extracellular fluid. Its relatively high increase was necessary to make spontaneous spike discharges disappear totally. All effects of the two contrast media, observed in this study, were due to the increase of osmotic pressure of the extracellular fluid ; no specific effect of the contrast media containing the iodine on the indicators used was observed.