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Biomedical subjects

Z Ito

Publications and source records attributed to Z Ito.

At least 37 records · Page 2Linked to original sources
PubMed1984

Intraoperative topical nimodipine after aneurysm clipping.

The lipophilic calcium antagonist Nimodipine (Bayer Pharma , Wuppertal ) was administered during aneurysm operations in 40 patients with ruptured intracranial aneurysm. Immediately after clipping of the aneurysm, a 2.4 X 10(-5) M solution of Nimodipine in 18 ml of Ringer's solution was injected into the subarachnoid space near the site of aneurysm clipping. Arterial vessels regularly dilated and spastic portions resumed their normal diameters. Since it is known from experimental work, that Nimodipine has stronger dilator capacity than papaverine and acts at least for several hours, two conclusions are drawn from the present preliminary study: Pre-operative vasospasm seen on angiograms is no longer a contraindication to early operation because spasm detected intraoperatively can be effectively treated. The long-lasting effect of Nimodipine prevents ischaemic complications in the first few days after operation and thereby seems to exert a protective effect against the onset of severe symptomatic vasospasm.

Administration, Topical↗
PubMed1983

Regulation of interdigestive contractions in the denervated stomach.

The effects of thiopental sodium on the regulation of interdigestive migrating contractions (IMC) in the stomach were investigated in dogs with extrinsically denervated fundic pouches. During the interdigestive state, strong phasic contractions in the pouch took place consistently in accordance with the IMC in the main stomach. The cyclic increase in plasma motilin concentration was more closely correlated with the increase in contractile activity in the pouch than the increase in the main stomach. General anesthesia by thiopental sodium promptly inhibited the IMC in the main stomach but the contractile activity in the pouch was not affected but gradually decreased in proportion to the decrease in plasma motilin concentration. In conclusion, contractile activity in the extrinsically denervated pouch, which is quite independent of the CNS, is directly controlled by a humoral factor(s), motilin. However, interdigestive motor activity in the extrinsically intact stomach appears to be regulated by the CNS as well as peripheral circulation humoral factors.

Anesthesia, General↗
PubMed1982

Brain dysfunction following vasospasm evaluated by somatosensory evoked potentials.

Somatosensory evoked potentials (SEP) were recorded in 9 patients with vasospasm caused by subarachnoid haemorrhage. There was a correlation between SEP changes and clinical outcome evaluated one month after onset. And, evaluation of SEP changes under induced hypertension or infusion of dehydrates was available to study the nature of ischaemic brain dysfunction caused by vasospasm. Furthermore, this study suggests that the available period of induced hypertension may be short in cases with severe clinical outcomes.

Brain↗
PubMed1982

The microsurgical anterior interhemispheric approach suitably applied to ruptured aneurysms of the anterior communicating artery in the acute stage.

From 1973 to 1980, 177 cases with ruptured aneurysms of the anterior communicating artery (Aco) have been operated on using various microsurgical procedures. Since 1974, 136 cases were directly operated on using the microsurgical anterior interhemispheric (AIH) approach: a modification of Lougheed's approach. The overall mortality was 5%. The early operations, within 1 week of onset of subarachnoid haemorrhage had a 3% mortality in grade 1 and 2 patients; a 16% mortality in grade 3 and 4 and a 25% mortality in grade 5 patients. The rate of cases in which the patient was independent following surgery was 92% in grade 1 and 2 patients, 47% in grade 3 and 4, and 25% in grade 5 in the same group. The AIH approach for severe cases in the acute stage has the following benefits: 1. The retraction pressure on the brain in the AIH approach is half as much as that in Yaşargil's approach. The aneurysms can be operated on with less retraction of the brain and thus without damaging the brain, olfactory nerves, bridging veins, hypothalamic arteries and other perforating arteries. 2. Various types of aneurysms, whatever their position, especially those located high and in a posterior direction, can be easily clipped. 3. Adequate removal of clots can be achieved from the interhemispheric fissure, the chiasmatic and the prepontine cisterns and the frontal lobe. 4. Interarterial anastomosis between both anterior cerebral arteries can be applied if necessary to allow easy clipping on unusual aneurysms. 5. Temporary occlusion of A1's and A2's and external decompression can be easily done if necessary.

Acute Disease↗
PubMed1982

Extensive evacuation of subarachnoid clot for prevention of vasospasm--effective or not?

The effect of subarachnoid haematoma (clot) evacuation for the prevention of vasospasm (VS) in the acute state was studied using 62 ruptured IC and MC aneurysm cases. Extensive clot evacuation within 48 hours after the onset did not prevent the development of VS but reduced the severity of VS, especially in the main trunks of the cerebral arteries (IC, M1, M2, A1). But excessive clot evaluation applied to the angry, swollen brain in the acute stage worsened the brain swelling and sometimes formed an intracerebral haematoma due to brain compression. The extent of the clot evacuation should be determined by preoperative CT findings and the brain's condition during the operation.

Acute Disease↗
PubMed1982

Surgical problems and pathophysiology in severe cases with ruptured aneurysm in the acute stage.

We have managed 674 cases of ruptured aneurysms of the anterior part of the circles of Willis during the period 1969 to 1980. For this study, analyses were made to clarify the operative indication, timing and suitable procedures based on the pathophysiology of severe cases in the acute stage. Clinical results on conservative treatment in the era of delayed operation clearly show the inevitable necessity of early operation. The CBF measurement in the acute stage revealed a slight decrease of hemispheric CBF without regulatory dysfunction of cerebral circulation within 3 days of SAH. Results of early operation within 3 days of SAH in the 3rd era showed that 83.1% of cases survived with a good outcome and 3.4% died when they were in Grades 1 and 2. 40 cases with severe grading, operated on within 3 days of SAH, were studied on each site of the aneurysm. Mortality was 12.5% and there was a favourable outcome in 55%. Death was due to brain swelling caused by vasospasm and direct brain damage caused by SAH and an intracerebral haematoma. Extensive evacuation of subarachnoid clotting could be performed only when brain volume could be reduced enough to minimize brain compression, by using ventricular drainage, evacuation of the intracerebral haematoma and Mannitol administration. Surgical procedures for each aneurysm are also described.

Acute Disease↗
PubMed1982

Prevention of symptomatic vasospasm by topically applied nimodipine.

A 2.4 x 10(-5) M solution of the Calcium-antagonist Nimodipine was administered to the exposed cerebral vessels in 17 patients intraoperatively clipping of a ruptured aneurysm. The interval between subarachnoid haemorrhage and operation was 48 to 72 hours. The CT investigation had revealed blood accumulation in the basal cisterns in all cases. Vasodilatation was observed in all instances; the percentage being greater in small vessels as compared to large vessels. Postoperatively, a neurological deficit combined with angiographically verified vasospasm occurred in two patients, but was reversible in both. Fifteen patients remained free from symptomatic vasospasm and were discharged without neurological deficit. In 13 of these patients and 3 additional cases, a plastic cannula was placed intraoperatively so that postoperative topical administration of Nimodipine was possible. Postoperative control-angiograms after a mean interval of 7 days from SAH did not show severe spasm in any of the patients; localised moderate asymptomatic spasm was found in 8 cases and was reserved in 5. Moderate postoperative symptomatic spasm was observed in 2 patients, treated and reversed in one patient. In 5 of 7 cases without evidence of spasm in the angiogram postoperative topical administration of Nimodipine caused vasodilatation. It is concluded, that topical intracisternal administration of Nimodipine reverses intraoperative vascular spasm and decreases the probability of postoperative symptomatic vasospasm after early surgery.

Administration, Topical↗
PubMed1982

[Incidental meningioma].

Intracranial tumors are accidentally discovered during operations for neurosurgical diseases, such as head trauma or cerebral aneurysm. Furthermore, in the autopsy specimen, intracranial tumors which had not been recognized before the patient's life are sometimes found incidentally. Those tumors are; meningioma, glioma, pituitary adenoma, and so forth. Among these instances, meningioma seems to be the most frequent. In this paper, the authors discussed five cases of asymptomatic meningiomas found unexpectedly, referred as "Incidental Meningioma." Incidental meningioma listed up here are five out of 38 clinical cases with intracranial meningioma which authors experienced during recent twelve years in our hospital. In 480 autopsy cases in our hospital in the same period, there was only one case with which incidental intracranial tumor was detected. This incidental tumor was index-finger tip sized parasagittal meningioma. This was not included in this series. These 5 clinical cases were composed of all women ranging in age from 48 to 72 years. Three of them were discovered during aneurysm surgery, the other one was found during the evacuation of acute subdural hematoma. The remaining one case (Case 5) was demonstrated intracranial meningioma unexpectedly by CT scanning. The size of those tumors were ranged from 7 to 20 mm in diameter except Case 5. In Case 5, tumor size was about 30x40 mm in diameter. The localization of those tumors were; three convexity, one pterion, and one falx meningiomas. Positive findings referable to those tumors at ancillary neuroradiological examinations, were shown only in one case (Case 2) with the exception of Case 5 retrospectively. That was abnormal calcified shadow in frontal bone at the right side in Case 2. The histological nature of them was various, but psammomatous type belonging to transitional meningioma was worthy to note, because such a type was relatively rare in our total cases. Incidental tumors seemed to be relatively rare in cases with cerebral aneurysm. In our series comprising 747 operated cases for cerebral aneurysm, there were 5 cases with incidental tumor (0.67%). Three of these 5 cases were incidental meningioma which were listed up in the paper. In all cases with incidental meningioma, except for Case 5, there were no definite feeding arteries, and they could be easily extirpated, with uneventful recovery.

Aged↗
PubMed1981

[Extravasation of contrast media in an acute stage of middle cerebral artery occlusion-in relation to haemorrhagic infarction (author's transl)].

Following an embolic occlusion of a major cerebral artery with peripheral migration of emboli in the early stage, cerebral haemorrhage from the recanalized perforators may occur in the infarcted zone. The following is a report of such a case. This 66-year-old-man with normotension suffered from sudden unconsciousness and left-sided paresis. On admission to our clinic five hours after onset, the patient was confused with urinary incontinence, left hemiplegia and irregular pulse. The first CT examination, which was performed immediately after admission, showed a small-sized haematoma surrounded by an obscure broad low density area in the region of the right caudate nucleus. Right carotid angiography which was performed after CT scan revealed an occlusion at the trifurcation level of the right middle cerebral artery and extravasation of contrast media from the right lenticulostriate arteries. Because of deterioration of the patient's condition, a second CT scan was done showing an extensive haematoma in the whole basal ganglionic region with ventricular rupture. An emergency decompressive craniectomy with evacuation of the haematoma was carried out with immediate postoperative improvement of the patient's condition. Judging from the mode of onset, clinical course as well as neuroradiological and preoperative findings, the pathogenesis behind the haemorrhagic infarction could be interpreted as follows: At the onset, a thromboembolic occlusion probably occurred in the right internal carotid artery with lack of sufficient collateral circulation. Before or during the first CT examination, the embolus may have migrated to the middle cerebral artery. Therefore, the reflow in the perforating arteries in the head of the caudate nucleus could have led to a haemorrhage in the infarcted area. Furthermore, the insufficiency of the lenticulostriate arteries expressed by extravasation of contrast media might be due to the high pressure reflow of the ischaemic vessels with increased permeability after further peripheral migration of the embolus. As a result, a huge and extensive haemorrhage took place in the infarcted area in the basal-ganglionic region. This phenomenon may be identical with the so-called "haemorrhagic infarction".

Acute Disease↗