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Biomedical subjects

N Moriyasu

Publications and source records attributed to N Moriyasu.

At least 55 records · Page 3Linked to original sources
PubMed1977

[Modulating mechanism of the dorsal column stimulation for pain relief (author's transl)].

The neural mechanism of the modulating effects of spinal cord stimulation upon intractable pain was studied in cats under local anaesthesia. The electrical activity at the centre median nucleus of the thalamus (CEM), which responded to noxious stimuli and was inhibited by nitrous oxide inhalation, was recorded as an indicator of the degree of pain sensation. The suppressed effect upon the evoked potential responding to sciatic stimulation (1 Hz) was recorded during and after train stimulation of various parts of the spinal cord by means of silver ball bipolar electrode. Whenever inhibitory modulating effect upon CEM response was observed by spinal cord stimulation, the bilateral dorsal tractotomy cranial, caudal or both to the stimulating point in order to examine the influence upon the CEM potential. The results are as follows: 1) The CEM evoked potential responding to sciatic stimulation is inhibited by about 30-45% of its amplitude by dorsal column stimulation. This effect corresponds to the inhibitory effect by 75% N2O gas inhalation. Upon dorsal column stimulation, the intraspinal electrical activity is found in the central gray matter the antero-lateral quandrants of the spinal cord as well as the dorsal column. 2) Following lateral or anterior column stimulation as well as dorsal column stimulation, the CEM evoked potential responding to sciatic stimulation is inhibited by about 50% of its amplitude. 3) Following bilateral dorsal tractotomy cranial, caudal or both to the stimulating point, the CEM evoked potentials responding to sciatic stimulation are inhibited by dorsal column stimulation. According to the experimental results, it may be concluded that the inhibitory modulating mechanism by dorsal column stimulation for pain relief is not only mediated through the dorsal column, but also through other ascending spinal pathways.

Animals↗
PubMed1975

[Ventricular enlargement in experimental occlusion of superior sagittal sinus--in reference to histopathological findings (author's transl)].

An experimental occlusion of superior sagittal sinus was made in dogs according to ligation with thread at the posterior third portion of the sinus. Ventricular enlargement and histological changes in the cerebrum were studied in various stage after occulusion of the sinus. In the acute stage, no ventricular enlargement occured. However, in the chronic stage, nine dogs out of 12 dogs showed enlargement of the ventricle. Hitological examination revealed peeled ependymal layer from subependymal tissue, edematous findings in the periventricular tissue, perivascular gliofibrosis, perivascular hemorrhage, exanguination of plasm, and venous stasis in the ventricular wall and cerebral cortex in convexity. Extracellular space in the subependymal tissue, and the space between pial and glial membrane were widened remarkably. Two factors were raised by authors as the pathogenesis for ventricular enlargement. One factor was the hydrodynamic disturbance of CSF according to the CSF malabsorption into the superior sagittal sinus through arachnoid villi. The other one was the disturbance of venous circulation due to occlusion of the sinus.

Animals↗
PubMed1975

[Electron microscopic study of choroid plexus in experimentally induced hydrocephalic dog (author's transl)].

Choroid plexus in experimentally induced hydrocephalic dogs according to the Wisniewski's method was examined by an electron microscope. Epithelial cell of the choroid plexus appeared in various deformation and formed a marked dilatation of extracellular spaces between apposed two cell membranes and at the basal interdigitation. Dilatation of the extracellular space was more pronounced at the stromal side of the epithelial layer. This finding might be due to anatomical specificities of apposed epithelial cell membranes and not only indicate a disturbance of the CSF secretion. According to the dilatation of extracellular space, apposed two epithelial cell membranes separated each other, however, at sites of intercellular junctions, adjacent cell membranes remained closely apposed. The dilated extracellular space at the basal site continued to the dilated intercellular space, while, no continuity was recognized between the dilated intercellular space and ventricular lumen. These extracellular speces appeared low electron density and showed little specific structure. No particular change was recognized in organelles in the epithelial cell, except increased pinocytotic vesicles in number. Stroma of the choroid plexus appeared edematous, that was, electron density was low and a few cellular and stromal elements were found. Capillary vessels showed almost normal structure. In hydrocephalic dogs also in normal one, Lanthanum infused into lateral ventricle precipitated on the surface of microvilli of choroid plexus epithelial cell. The Lanthanum, entered through ventricular end of intercellular space, was blocked to penetrate beyond the intercellular junction (zonula occludens) and any bit of the tracer was not found in the dilated extracellular space. The tracer was found neither in epithelial cell nor in stroma. These findings of tracer-study may indicate that the CSF absorption through the choroid plexus is not increased in chronic hydrocephalus. Consequently, the ultrastructural changes of the choroid plexus in chronic hydrocephalus, that is, enlarged extracellualr space, increased pinocytotic vesicles and edematous stroma, are thought to suggest a disturbance of CSF secretion from the choroid plexus.

Animals↗
PubMed1975

[Treatment for traumatic aneurysm of the cerebral artery--identification between deteriorating type and spontaneously disappearing type (author's transl)].

Thirty five cases of traumatic aneurysm of the cortical cerebral artery were reviewed in the literatures cited in the references. Five cases of them healed spontaneously without operative treatment (disappearing type), the other cases underwent direct operation of aneurysm, in spite of high operative moltality or mobility (deteriorating type). Recently four cases of traumatic aneurysm of the cortical cerebral artery were treated in our clinic. Three cases which had the aneurysm in the pericallosal artery (1 case) and middle cerebral artery (2 cases) respectively underwent radical operation for treatment as progressively deteriorating type and fourth case which had the aneurysm in the peripheral part of the frontopolar artery was treated by medication as the spontaneously disappearing type until the aneurysm disappeared on the angiogram. According to the review of literatures, it is the most important for the treatment of tramatic aneurysm to know whether disappearing type or deteriorating type, because deteriorating type had bad prognosis without radical operation and the prognosis of disappearing type was excellent without operation. Analysing the clinical signs and angiographical findings of the all cases, the authors found out some specific characteristics of the spontaneously disappearing type. are (1) The aneurysm is found in the relativery late post traumatic stage except for cases caused by penetrating wound, (2) The irregular shape, uneven opacity of the aneurysm without clear neck connecting with pearent artery on angiography, (3) Shape and size of the aneurysm in follow up angiogram (two weeks or more) became smaller, (4) Around of aneurysm, there are not any kind of intracranical hemetoma. According to these results, differential diagnosis between spontaneously disappearing type and deteriorating type was done in the author's four cases and the three cases of deteriorating type were relieved by radical operation without any postoperative disability and one case of spontaneously disappearing type was treated by medical treatment until disappear of aneurysm. It is concluded that traumatic aneurysm of the cortical cerebral artery is relative rare and it is important to know whether deteriorating type or spontaneously disappearing type in order to get excellent results.

Adolescent↗
PubMed1975

[Hydrodynamic of the C.S.E. under experimental occlusion of superior sagittal sinus (author's transl)].

It is recognized that absorption of C.S.F. occurs mainly at the superior sagittal sinus through arachnoid villi after study of the Retzius (1875) and Weed (1914). We are interested in C.S.F. circulation and pathway on the obstructed superior sagittal sinus. At the border of middle one third and posterior one third of the superior sagittal sinus was obstructed experimentally. 1. When evans blue 0.5 to 1.0 ml was injected into lateral ventricle or cisterna magna, the evans blue was recognized on basal surface in either normal and obstructed dog of the superior sagittal sinus. Evans blue stained the convexity of normal dog, however, did not stain the convexity in the dog of obstructed superior sagittal sinus contrally. This was caused by the disturbance of C.S.F. circulation toward superior sagittal sinus. On the intraventricular injection of evans blue, it infiltrated into parenchym from ventripcle due to C.S.F. circulatory disturbance. 2. Study of radioactivity in the peripheral blood after intracisternal or intraventricular injection of RISA 100 muCi revealed that the radioactivity in the blood lowered with day after obstruction of superior sagittal sinus comparing with normal dogs. 3. Macroautoradiography after intracisternal or intraventricular injection of P 2mCi showed lower RI activity at the convexity, but increased activity at the basal brain in the obstructed dogs of superior sagittal sinus. These results showed that C.S.F. in normal dog was absorbed through the brain surface, expecially the basal surface of brain, other than through the superior sagittal sinus. Absorption of C.S.F. through the convexity of brain was disturbed significantly in the obstructed dogs of superior sagittal sinus. C.S.F. absorption into peripheral blood decreased in chronic stage after occlusion of surperior sagittal sinus and it suggested that the absorptive function of C.S.F. through the basal surface of brain was restricted.

Absorption↗