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Biomedical subjects

T Iwabuchi

Publications and source records attributed to T Iwabuchi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Posterior inferior cerebellar artery aneurysm located in the spinal canal--case report.

A 30-year-old male presented with subarachnoid hemorrhage, due to a rare peripheral posterior inferior cerebellar artery aneurysm located in the spinal canal. Angiography and magnetic resonance imaging disclosed the aneurysm of 15 mm diameter at the C-1 level. After aneurysmal neck clipping and ventriculoperitoneal shunt implacement, he was discharged without neurological deficit. Histological examination revealed no layer formation, only hemorrhage and organization in the aneurysmal wall. This case may be an example of giant aneurysm formation caused by repeated bleeding and organization.

Adult↗
PubMed1995

Effects of immunosuppressive peptidyl-prolyl cis-trans isomerase (PPIase) inhibitors, cyclosporin A, FK506, ascomycin and rapamycin, on hair growth initiation in mouse: immunosuppression is not required for new hair growth.

The effects of immunosuppressive peptidyl-prolyl cis-trans isomerase (PPIase) inhibitors, cyclosporin A, FK506, ascomycin and rapamycin, on hair growth initiation (anagen hair induction) in mouse were studied by topical application on the dorsal skin surface during the telogen phase of the hair cycle. Single applications of cyclosporin A and FK506 (10 to 100 nmol in 5 microliters of ethanol) induced new hair growth in 12 days within the restricted area where the compounds were applied. On the other hand, ascomycin and rapamycin did not initiate new anagen hairs even at higher doses (1 mumol in 5 to 10 microliters of ethanol). The effects of simultaneous application of the immunosuppressants were also tested by a single topical application. Ascomycin did not inhibit the anagen hair induction by cyclosporin A, but inhibited hair induction by FK506. Rapamycin inhibited new hair growth induced by cyclosporin A and FK506. These results suggest that the inhibition of PPIase is not required for the initiation of a new hair cycle in mice, and that anagen hair induction caused by cyclosporin A and FK506 is not a result of immunosuppression. The present results also indicate that a single application of an adequate quantity of cyclosporin A and FK506 is sufficient to initiate new hair growth.

Administration, Topical↗
PubMed1995

[Report of a case of bilateral adrenal teratoma with CA19-9 production].

Reports of adrenal teratomas in adults are rare, and all of adrenal teratomas which were reported in the literature were found in unilateral adrenal gland. This is the first reported case of CA19-9 producing huge teratomas found in bilateral adrenal gland. Twenty-two year-old woman was hospitalized for an episode of abdominal growing mass and an abnormality of high CA19-9 serum level. Operatively, bilateral adrenal tumors were removed, and the weights of right one and left one were 3976g and 618g, respectively. Histological diagnosis of both tumors was mature teratoma. Immunohistochemical findings revealed CA19-9 was produced from intestinal epithelium in teratoma.

Adrenal Gland Neoplasms↗
PubMed1994

Efficacy of steroid hormone in solution for intracranial irrigation during aneurysmal surgery for prevention of the vasospasm syndrome.

A series of 55 patients with ruptured cerebral aneurysms were treated with moderate removal of subarachnoid clot followed by intracranial irrigation with pH 8.0 Hartmann solution containing 1 mg/ml of methylpredonisolone sodium succinate after the aneurysmal clipping during early (before day 3) operation. Six (11%) of the 55 patients suffered vasospasm syndrome postoperatively. The clinical results are significantly better than a series of 68 patients operated on and treated before day 3 by intracranial irrigation with Hartmann solution (pH 8.0) only. The possible preventive effect of direct intracranial administration of steroid hormone is discussed.

Adult↗
PubMed1994

[Pineal cyst: its diagnosis and treatment].

Four cases of pineal cyst were presented and their features on magnetic resonance (MR) imaging were discussed while reviewing the literature relevant to this clinical entity. Pineal cyst is a normal developmental variant and in most of the cases its diagnosis is not difficult, but in a limited number of cases, pineal cyst needs to be differentiated from cystic tumors which have developed in the region of the pineal gland, such as pineocytoma or astrocytoma. Most pineal cysts are found incidentally during MR screening studies and no surgical interventions are needed. Pineal cysts should be considered for surgery only when the diameter of the cyst is more than 1.0cm, or when obstructive hydrocephalus is verified on MRI or CT, and/or when definitive neurological signs such as Parinaud's syndrome are present. It was also stressed that embryological considerations are indispensable for evaluating pineal cysts on MR images.

Adolescent↗
PubMed1994

[A plurihormonal adenoma: a case report].

A case of prolactinoma secreting growth hormone is reported. A 32-year-old woman was admitted to our hospital complaining of galactorrhea, amenorrhea and bitemporal hemianopsia. She showed hyperprolactinemia about 500ng/ml and elevated growth hormone level over 10ng/ml without clinical features of acromegaly. Static perimetry represented typical bitemporal hemianopsia better than kinetic perimetry in the early stage of this pituitary tumor. Her visual acuity was 1.0 on the right and 0.02 on the left. MR images showed the intra-and suprasellar mass lesion compressing the optic nerves especially on the left. Because her visual acuity deteriorated rapidly, trans-sphenoidal tumor resection was carried out twelve days after admission. Total removal was achieved. Postoperative MRI showed that the normal pituitary gland had been preserved. The patient's visual acuity recovered to 1.2 on the right and 0.9 on the left, and bitemporal hemianopsia improved remarkably. Postoperative course was uneventful and hormonal functions were normalized. Histological examination showed that the tumor was chromophobe adnoma. The adnoma cells showed immunopositivity for growth hormone, but not for prolactin. Such absence of prolactin granules within cytoplasm might be due to the difference in antigen produced by the adenomatous gland as compared with that produced by the normal gland. Although hyperprolactinemia is often observed in acromegaly, hypersecretion of growth hormone in prolactinoma as was found in this case is very rare in medical literature.

Adenoma, Chromophobe↗
PubMed1994

[Transverse sinus thrombosis in a patient with colon and rectal double cancers: a case report].

We report a case of transverse sinus thrombosis accompanied by colon and rectal double cancers. A 48-year-old male transferred to our department from the division of surgery due to deterioration manifested by headache after colectomy and low anterior resection of the rectum. There was bilateral papilledema and right upper homonymous hemianopsia. On admission all the laboratory data were within normal range. CT showed a left temporal mass lesion of heterogeneous density, which was suspected as being intratumorous hematoma in a metastasis. MRI revealed a left transverse sinus thrombosis. The left transverse and sigmoid sinuses were not opacified, but angiography showed that the occipital and marginal sinuses seemed to be markedly developed. Evacuation of the subcortical hematoma was carried out. Histologically, it was a mixed hematoma in acute and chronic stages without any carcinoma component or vascular malformation. Postoperative course was uneventful, and the patient was returned to the division of surgery in order to follow up the cancer 2 weeks after operation. Angiography 4 months after operation showed almost no recanalization in the left transverse sinus. Further, development of the collateral flow and the double occipital sinus was opacified. Because the coagulation system is often activated by the presence of cancer, it is important to distinguish intracerebral hemorrhage due to sinus thrombosis from intratumorous hemorrhage within a metastatic tumor.

Adenocarcinoma↗
PubMed1994

[Traumatic hematoma in the basal ganglia (caudate) with favorable prognosis: report of two cases].

Two cases of traumatic basal ganglial hematoma with fairly good prognosis were reported. Several cases with similarly favorable prognosis could be also found in the recent literature. In these cases, post-traumatic disturbance in consciousness was mostly slight or moderate and the patients were rarely comatose. The inquiries in these cases were commonly associated with superficial injuries such as skull fracture, epi-or sub-dural hematoma, brain contusion, or another traumatic ICH. The hematomas in the basal ganglia usually showed a mass effect causing focal neurological signs such as hemiparesis. Neurological improvement was achieved in the operated cases, and final outcome was mostly fair with some fully recovered cases. These clinical features are quite different from those of most cases of traumatic basal ganglial hematoma reported so far, which closely resemble diffuse axonal injury and whose prognoses are extremely poor. There may be two different categories in the traumatic basal ganglial hematomas, those with fair outcomes, and those with poor outcomes.

Aged↗
PubMed1993

Preliminary experimental study on a newly-developed coating material (liquid cellulose) for cerebral aneurysms.

We have developed a new coating material for cerebral aneurysms consisting of cellulose. The possible usefulness of this ethyl cellulose-ethyl acetate solution ("Liquid cellulose") as a coating material was evaluated as follows: 1) The liquid cellulose (ethyl cellulose concentration, 10%; degree of polymerization, 100) and Biobond had pHs of 7.35 and 3.16, and viscosities of 1,385 and 626 cp, respectively. The properties of the coat (N = 30, M +/- SD) of the liquid cellulose and Biobond at a cast coat thickness of 254 microns were as follows: coat thickness after drying (microns), 17.8 +/- 2.8 and 109.8 +/- 44.2; coat formation time (sec), 62 and 1,800; strength of the coat (gm), 432.3 +/- 51.4 and 8.0 +/- 5.6; strength index (kg/cm2), 572.8 +/- 84.7 and 2.4 +/- 1.8; and elongation index (%), 14.8 +/- 3.5 and 705 +/- 188.8, respectively. The coat using liquid cellulose was more physiological and far stronger. It was also more readily manipulated during the operation than Biobond. 2) The liquid cellulose showed excellent adhesiveness when applied to the vascular wall. Sequential histological observations for 12 months showed that the liquid cellulose remained stable without histotoxicity or cracks in the coat. These results indicate the potential usefulness of this agent for reinforcing the vascular wall.

Acetates↗
PubMed1993

Neurological improvement after cranioplasty. Analysis by dynamic CT scan.

The authors studied the changes in neurological signs and cerebral circulation by using dynamic CT scans before and after cranioplasty in six externally decompressed patients. Five of the 6 patients showed some improvements in neurological signs. The results of the dynamic CT scans in 6 cases suggested that increases of bilateral cerebral blood flow may play a role in their neurological improvement.

Adult↗
PubMed1993

Intraoperative recordings of evoked extraocular muscle activities to monitor ocular motor nerve function.

During 22 operations in 18 patients, we stimulated the ocular motor nerves electrically, intracranially, and recorded compound muscle action potentials (CMAP) directly from the extraocular muscles with a ring electrode that we developed. Recording electrodes were applied in 52 instances to the superior rectus, medial rectus, superior oblique, or lateral rectus muscle and to the levator palpebrae superioris in 2 instances; CMAP were recorded successfully from 22 muscles. Evoked CMAP were not recorded in 2 instances because of problems with recording equipment; in the remaining 30 instances, no evoked CMAP were recorded because 1) the oculomotor or abducens nerve was not exposed during the operation; or 2) the recording electrode on the superior oblique muscle had not been properly placed to record trochlear nerve CMAP. Placement of this electrode is difficult. Ocular motor nerve function was analyzed preoperatively and postoperatively to evaluate the usefulness of this intraoperative electrophysiological monitoring method in preventing damage to ocular motor nerves. The results of this study showed that monitoring enables surgeons to locate precisely ocular motor nerves that would otherwise have been overlooked and thus possibly injured during surgery. Monitoring results also confirmed the surgeons' visual findings, thus helping the surgeons operate with greater confidence. Further, intraoperative monitoring provided us with some insights into the pathophysiology of ocular motor nerve dysfunction caused by skull base lesions; we documented electrophysiologically the occurrence of the slowing of conduction in the ocular motor nerves. We conclude that monitoring ocular motor nerve CMAP can reduce the incidence of surgical complications such as functional blindness due to inadvertent sectioning of one of these nerves and that it would be worthwhile to conduct studies of this technique in many more cases to validate our findings.

Abducens Nerve↗
PubMed1993

[Subarachnoid hemorrhage and pontine hemorrhage followed by an embolization procedure of left occipital giant arteriovenous malformation: a case report].

A 42-year-old woman suddenly developed headache and nausea on July 26, 1991, and the computed tomography (CT) scan showed a moderate-sized hematoma in the left occipital lobe. After one month's conservative treatment, she had recovered to a neurologically intact state. Cerebral angiography demonstrated a giant arteriovenous malformation fed by enlarged branches of the left posterior cerebral artery as well as small branches arising from the middle cerebral artery, anterior cerebral artery and the meningeal branches of the middle meningeal artery and the occipital artery. Preoperative embolization was planned on February 24, 1992. During an attempt at catheterization of the basilar artery and the left posterior cerebral artery with a balloon catheter and a Tracker-18 catheter, the patient complained of an intensification of her headache, nausea and vomiting. So the embolization procedure was stopped. The CT scan taken immediately at that time showed a severe subarachnoid hemorrhage (SAH). She became comatose about 40 minutes later. CT scan taken next day revealed also a complication of the pontine hemorrhage. Neurologically, she had gradually recovered and could communicate with some simple words 3 months after SAH. The total removal of the AVM was performed on May 26, 1992. Postoperative course was uneventful. She showed rapid and remarkable improvement in her neurological state suggesting that the blood flow in the surrounding brain area had been corrected. A blood deficit had no doubt been caused when blood had been stolen by the giant AVM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Localization of central sulcus by means of cortical SEP recordings: clinical feasibility and usefulness of intraoperative electrophysiological monitoring].

Clinical feasibility and usefulness of various intraoperative electrophysiological monitoring methods that are widely utilized during neurosurgical operations were critically evaluated. We divided these intraoperative monitoring methods (IOM) into two types; the monitoring methods that enable the surgeons to obtain topographical orientation during operative procedures ('topographical IOM') and those that give them knowledge of the functional state of the nervous system that is involved in the operative procedures ('functional IOM'). It was shown why 'topographical IOM' is reliable and useful, based on our experiences of cortical SEP recordings to localize the central sulcus, and why the present 'functional IOM' is less reliable to guide the surgeons precisely during the operations. We presented some technical methods to cope with these problems in 'functional IOM'. It is necessary to establish a good correlation between the intraoperative changes of the evoked potentials and the pathological changes responsible for these electrical changes as established in clinical electrocardiography.

Adult↗
PubMed1993

[Two cases of well-known syndrome due to midbrain-brain stem hemorrhage--Weber's syndrome and one and a half syndrome].

Two cases of well-known syndrome due to midbrain-brain stem hemorrhage without having a history of hypertension were reported. Case 1 is a 62-year-old female, presenting Weber's syndrome due to midbrain hemorrhage and diagnosed as Moyamoya disease angiographically. Case 2 is a 24-year-old-male, presenting One and a half syndrome due to brain stem hemorrhage from a brain stem cavernous angioma, which was diagnosed angiographically and by magnetic resonance imaging (MRI). Left hemiparesis seen in case 1 had improved by conservative therapy but no improvement could be obtained in the oculomotor nerve palsy. In case 2, hematoma was aspirated surgically for the purpose of decompression and his neurological symptoms improved markedly. Their pathogenesis and pathophysiology were also discussed.

Adult↗
PubMed1993

[How to preserve the facial nerve in acoustic neurinoma excision: development of a microneurostimulator].

We developed a Micro-neurostimulator that is suitable for intracranial electrical stimulation of the facial nerve in excision of acoustic neurinomas. The tips of our Micro-neurostimulator were thinner and finer than those of commercially-available bipolar forceps and therefore it was possible to stimulate tumor tissue and the facial nerve selectively. This facilitated precise excision of tumor tissue from the facial nerve without residual tumor tissue around it. It was emphasized that the shape of the tips of stimulating electrodes and the stimulus intensity were the most important factors in obtaining reliable responses in preserving the facial nerve using intracranial electrical stimulation and evoked electromyographic responses.

Electric Stimulation↗
PubMed1992

A ring electrode to record extraocular muscle activities during skull base surgery.

A ring-shaped electrode was developed and used in 20 patients to record evoked electromyographic responses directly from the extraocular muscles during skull base surgery. Intra-operative monitoring with this electrode helps the surgeon to localize the nerves that innervate the extraocular muscles precisely and to refrain from disturbing important neural structures during operations. Such monitoring also provides some insight into the pathophysiology of the dysfunction of these nerves resulting from skull base lesions.

Abducens Nerve↗