Search PubMed⌕ Search

Biomedical subjects

Y Ishida

Publications and source records attributed to Y Ishida.

At least 775 records · Page 43Linked to original sources
PubMed1975

Interaction of Ca, Mg and ATP in glycerinated taenia coli of guinea pig.

Ca sensitivity and energy dependence in the contractile proteins of the glycerinated taenia coli of guinea pig were studied. Above 1 X 10(-7)M Ca caused contraction in muscle which had been immersed in glycerol solution for 7 days in the presence of 5 mM Mg-ATP. Muscles which had been immersed in glycerol for 30 days had a higher Ca sensitivity than ones in glycerol for 7 days. When AMP or ADP (5, 10 MM) in place of ATP was added in the presence of 1 X 10(-6) M Ca and Mg(5, 10 mM), there was no contraction. Increasing the concentration of the same molar ratio of Mg-ATP from 1 to 20 mM in the presence of 1 X 10(-6) M Ca, the tension increased according to the Mg-ATP concentration. However, increase in Mg or ATP only in the presence of 1 X 10(-6) M Ca did not increase the tension. In conclusion, the three factors of Ca, Mg and ATP are essential for the activation of the contractile elements of glycerinated taenia. It is also suggested that the tension development in glycerinated taemia is controlled by the concentration of Ca and Mg-ATP complexes in intracellular fluid.

Adenosine Diphosphate↗
PubMed1975

Difference between inhibitory actions of papaverine and dehydroepiandrosterone on the isolated guinea-pig ileum.

Dehydroepiandrosterone (DEA), a metabolite of steroid hormone in the urine, differed from papaverine in the mode of inhibitory action on the isolated guinea-pig ileum. Papaverine inhibited both phasic and tonic contractions induced by an agonist, while DEA inhibited the phasic contraction without apparent fatigue of the tonic phase. The main action of papaverine seems to be predominatly a metabolic inhibition similar to that of metabolic inhibitors, but the action of DEA could not be ascribed to that of metabolic inhibition. In the presence of papaverine or metabolic inhibitors the height of maximal contraction of an agonist tested by the cumulative method was greatly depressed and less than that by a single method. The longer the time involved in the cumulative doses, the lower was the maximal contraction.

Acetylcholine↗
PubMed1975

Optic organ and cervical proprioceptors in maintenance of body equilibrium.

Two experiments were made on the functional correlation between the optic organ and the cervical proprioceptors in maintenance of body equilibrium. Experiment I: The effects of weak and strong electric stimulation of the deep nuchal muscles on changes in optokinetic nystagmus and optokinetic after-nystagmus were examined in adult non-albino rabbits with binocular vision. Experiment II: Experiment I was repeated on rabbits with monocular vision giving optokinetic stimulation moving from the side of the blindfolded eye to that of the open eye and applying only weak electric stimulation to the neck muscles. The results obtained were as follows: (1) Experiment I: Weak electric stimulation of the deep nuchal muscles of rabbits with binocular vision tended to promote optokinetic nystagmus with either no significant change or decrease in optokinetic after-nystagmus. Strong electric stimulation had the opposite effects, i.e., it tended to inhibit optokinetic nystagmus and activate optokinetic after-nystagmus. It also produced abnormal optokinetic nystagmus, such as the inversion phenomenon of optokinetic nystagmus and "optokinetic nystagmus firing". (2) Experiment II: Weak electric stimulation of the deep nuchal muscles of rabbits with monocular vision had similar effects to those in experiment I, but promotion of optokinetic nystagmus was less obvious, while activation of optokinetic after-nystagmus was more marked. In addition, the inversion phenomenon of optokinetic nystagmus developed even on weak electric stimulation. From these results the following conclusions were drawn: (1) The cervical proprioceptors can function in two mechanisms causing promotion and break down of equilibrium of the optokinetic system. (2) The cervical proprioceptors, as an organ of equilibrium, can exert two different actions on the optokinetic eye reflexes, i.e., they can promote optokinetic nystagmus and inhibit optokinetic after-nystagmus.

Animals↗
PubMed1975

[Early diagnosis and selection of operative approach for acoustic neuroma (author's transl)].

The recent advances of various diagnostic procedures made possible to detect intracanalicular neuroma in early stage. The operative results have been also greatly improved by transtemporal approach using surgical microscope and dental burr. In addition, the revised suboccipital approach contributed to obtain better operative results. Reviewing our clinical experiences with 15 cases operated from May 1969 to December 1971, appropriate combination of applicable diagnostic procedures and selection of operative method are discussed. Multiple audiologic examinations consisting of pure tone audiometry, speech discrimination, Békésy audiometry, alternate binaural loudness balance test, tone decay and uncomfortable lebel were performed in 11 cases. 9 of these cases manifested retrocochlear type of hearing loss. Spontaneous nystagmus and induced nystagmus, together with balance test, were evaluated for vestibular function. Bithermal caloric test disclosed unilateral canal paresis in all cases. In 13 cases, spontaneous nystagmus was observed. Analysis of optokinetic nystagmus using electronystagmography suggested tumor invasion to the brain stem and cerebellum. Tomography of the internal auditory canal showed abnormal findings in all cases. Cisternography with 2 ml of myodil was performed in 7 cases, all of which were diagnosed definitely by filling defect. Angiography showed abnormal vascular displacement with the tumor of size exceeding 3 cm in diameter. Translabyrinthine approach was performed in 5 cases. Suboccipital approach was applied in 6 cases. Combined approach of these two routes was used in 4 cases. 11 patients returned to their original work postoperatively. To obtain the correct diagnosis of acoustic neuroma in early stage, multiple audiologic examination are indispensable together with detailed vestibular function tests when the unilateral sensory neural hearing loss is suspected. Tomography of the internal auditory canal is also advisable as routine roentonologic study. If the clinical sign is confined to the 8th nerve only, myodil cisternography is useful, however, angiography is reliable in more advanced cases. When the tumor size is below 2 cm and signs of the spread to the brain stem, cerebellum or lower cranial nerves are lacking, translabyrinthine approach is indicated. Suboccipital approach is advisable for more advanced cases or undefinitive cases. Planning of combined approach of both routes is seemed to be not necessary in any case from our experience.

Adult↗
PubMed1973

Studies on ataxia of lumbar origin in cases of vertigo due to whiplash injury.

We draw the following conclusions from clinical observations on traumatized patients with vertigo and lumbar pain. 1) Hypertonicity of the lumbar soft supporting tissues, and especially the lumbar erector muscles (i.e., over-excitment of the lumbar proprioceptors) is a cause of vertigo due to whiplash injury. Equilibrium tests after fixing the waist with a corset are useful for detecting ataxia of lumbar origin. 2) Over-excitement of the lumbar porpiroceptors and dysfunction of the brain stem and the cerebellum are closely related in bringing about vertigo due to whiplash injury. The lumbar proprioceptors in particular may be important, in close correlation with the cerebellum in producing vertigo of this type. 3) Infiltration of procaine into tender spots in the lumbar soft supporting tissues is helpful in therapy of disequilibrium of the eyes and body and of cerebellar ataxia.

Adult↗