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Biomedical subjects

K Mizoi

Publications and source records attributed to K Mizoi.

At least 109 records · Page 6Linked to original sources
PubMed1985

[Effects of cerebral protective agents in experimental cerebral ischemia. Relationship between the degree of ischemia and EEG].

We have previously demonstrated that the preischemic administration of perfluorochemicals (PFC) in combination with 20% mannitol, vitamin E and dexamethasone is effective in protecting the brain from cerebral ischemia. This experimental study was designed to evaluate the effect and limitation of the post-ischemic administration of those 4 agents on cerebral ischemia. We used "Canine model of complete ischemic brain regulated with a perfusion method." Using this model we were able to control the amount of blood flow to the left cerebral hemisphere by using an infusion pump. Infusion blood volume was reduced to 30%, 40% or 50% of the normal state, then the combined treatment was started 1,2,3,4,5 or 6 hours after the onset of ischemia in each ischemic group. By monitoring the EEG for 8 hours of ischemic period, we were able to evaluate the effect of the drugs on cerebral ischemia. In untreated groups, electrical activity deteriorated gradually. In the 30% ischemia group, the EEG became isoelectric within 1 hour following ischemia. In half of the 40% ischemia group, the EEG became isoelectric but in the other half low voltage slow wave were seen to last for 6-8 hours. In the 50% group, the EEG deteriorated gradually but did not disappear within 8 hours. The effectiveness of the treatment was judged by the degree of the recovery of electrical activity. The effectiveness of the treatment appeared to depend on the severity and the duration of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

The protective effect of vitamin E on cerebral ischemia.

Using the "canine model of the completely ischemic brain regulated with a perfusion method," the effects on cerebral ischemia of vitamin E, which is known to act as an antioxidant, were investigated. After pretreatment with vitamin E by oral or intravenous administration, cerebral blood flow was reduced to 1/10th the normal state and, 1 hour later, allowed to return to normal. Subsequent changes in electrical activity were observed, and the effects of vitamin E were evaluated. In the control group, no recovery of electrical activity was seen. In the groups given vitamin E, the recovery time was significantly shortened in the dogs given 30 mg/kg of vitamin E intravenously. Furthermore, in the groups treated with vitamin E, distinct recovery of electroencephalographic potentials at 3 hours after recirculation was apparent. These effects were more favorable in the case of intravenous administration than in the case of oral administration. These experimental results indicate that the administration of vitamin E is effective in protecting the brain from cerebral ischemia.

Animals↗
PubMed1984

Intracranial hemorrhage secondary to von Willebrand's disease and trauma.

A rare juvenile case of traumatic hemorrhage in the basal ganglia with intraventricular hematoma, associated with von Willebrand's disease, is reported. Hemostatic management of von Willebrand's disease and our surgical method for treatment of intraventricular hemorrhage are discussed briefly.

Cerebral Hemorrhage↗
PubMed1984

[Experimental study of cerebral protective effect on cerebral ischemia of various antioxidants and other agents. With special reference to the combined treatment of mannitol, vitamin E, dexamethasone and perfluorochemicals].

We have previously reported that the combined administration of mannitol and perfluorochemical blood substitutes is evidently effective in protecting the brain from cerebral ischemia. This experimental study was designed to develop more effective method in suppressing brain infarction than the combined treatment of mannitol and PFC. Using the "Canine model of complete ischemic brain regulated with a perfusion method" in which it is possible to control the degree of blood flow to a cerebral hemisphere via a perfusion pump, the effect of eight agents including six kinds as the free radical scavenger on cerebral ischemia was investigated. Eight agents were mannitol, vitamin E (Vit. E), dimethyl sulfoxide (DMSO), vitamin C, glycerol, nizofenone (Y-9179), dexamethasone (Dexa.) and suloctidil (MY-103). After pretreatment with each agent, blood flow was reduced via the pump to 1/10 of the normal state and 1 hour later, return to the normal state was allowed. Subsequent changes in EEG were observed and the effects of the drugs evaluated. In the control group, no recovery of electrical activity was seen, but in six groups among eight treated groups, i.e., treated with mannitol, Vit. E, DMSO, MY-103, Y-9179 and Dexa, gradual emergence of slow waves was observed. And more favorable effects were found when the combined administration of mannitol, Vit. E and Dexa was made in the same experimental schedule as compared with the single administration of each of these drugs. Furthermore in the animals administered with PFC in combination with mannitol, Vit. E and Dexa, flattening of electrical activity could not be seen throughout the period of severe ischemia. Moreover, the power of electrical activity recovered nearly to the preischemic state immediately after recirculation. Although the possible mechanisms are not yet completely clarified, the present results are thought to indicate that this new combination therapy utilizing PFC with mannitol, Vit. E and Dexa may be useful in the treatment of cerebral ischemia.

Animals↗
PubMed1984

[An experimental study on the protective effect of nizofenone in cerebral ischemia].

Using the "canine model of complete ischemic brain regulated with a perfusion method" in which it is possible to control the degree of blood flow to a cerebral hemisphere via a perfusion pump, the protective effects of nizofenone against cerebral ischemia was investigated. After pre-treatment with nizofenone, blood flow was reduced via the pump to 1/10 of the normal state and 1 hour later, return to the normal state was allowed. Subsequent changes in EEG activity were observed and the effect of nizofenone evaluated. In the control group, no recovery of EEG was seen following recirculation, but in the group treated with nizofenone, gradual emergence of slow waves was observed. And the degree of recovery of EEG was better in the group administered a large dosage than in those given a low dosage. Our study suggested that within the dose ranges tested, nizofenone ameliorated ischemic brain damage in a dose dependent fashion. But the application of this experimental results to the human clinical situation requires that particular note should be paid to the dangers of transient fall of blood pressure at higher dosages.

Animals↗
PubMed1983

[Acute epidural hematoma in the posterior fossa in patients with hemophilia A--report of two surgically treated cases].

Case I: A 9-year-old boy, diagnosed as having hemophilia A at 8 months, was admitted complaining of slight headache and nausea one day after a minor head trauma. Neurological deficits were absent but CT scan revealed an epidural hematoma in the posterior fossa. Shortly afterwards, he lapsed into coma with apnea and dilated pupils. Following resuscitation, emergency suboccipital craniectomy and total removal of the bilateral supra- and infratentorial extradural hematoma was performed under AHG administration. The patient gradually regained consciousness, but during the subsequent nine weeks he underwent three major operations (laparotomy): the first two for hemostasis of gastrointestinal bleeding, and the last one for strangulated intestinal obstruction. Although this patient necessitated 16 weeks of AHG administration, he was discharged without any side effects after 4 months of hospitalization. Case II: A 10-year-old boy, diagnosed earlier as having hemophilia A, experienced a minor head trauma and was admitted because of headaches and nausea. CT scan revealed an epidural hematoma in the posterior fossa. Removal of the hematoma was successfully completed under AHG administration. The patient was discharged without any neurological deficits. In the above hemophilic cases, we used a high concentrated AHG and maintained at 70% of the plasma concentration of the VIII factor during the first 14 postoperative days. The high concentrated AHG was safe for long term administration, so one should not hesitate operation even in the case of intracranial hemorrhage of hemophilic patients. CT scan should be recommended to the patient of hemophilia A even in minor head trauma.

Acute Disease↗
PubMed1983

[Combined use of mannitol and perfluorochemicals in experimental cerebral ischemia].

Using the "canine model of complete ischemic brain regulated with a perfusion method" in which it is possible to control the degree of blood flow to a cerebral hemisphere via a perfusion pump, the effects of mannitol (which acts as a free radical scavenger) and perfluorochemical emulsion (PFC, which has 0.1 micrograms of average particle size and a high oxygen-carrying capacity) on cerebral ischemia were investigated. After pretreatment with the drugs, blood flow was reduced via the pump to 1/10 of the normal flow volume and 1 hour later, return to a normal flow was allowed. Subsequent changes in electrical activity were observed and the effects of the drugs evaluated. In the control group, no recovery of electrical activity was seen, but in the animals treated with either mannitol or PFC, incomplete, yet distinct recovery was apparent. In the animals administered with mannitol together with PFC, however, marked recovery was evident. These experimental results indicated that a combined administration of PFC and mannitol is effective in protecting the brain from cerebral ischemia.

Animals↗
PubMed1983

[Intracranial hemorrhage in von Willebrand's disease.--A case report].

A rare case of intracranial hemorrhage proved associated with von Willebrand's disease was reported. A 4-year-old girl fell down and hit her occipital region against a small wooden case. Soon after she cried for a few minutes, but she gradually became unconscious. Four hours later she was brought to our hospital. On admission she was semicomatose with left hemiparesis. There was no evidence of head injury and plain skull films were normal. CT scan disclosed a hematoma in the right basal ganglia with a ventricular hemorrhage. No vascular malformations were seen on the carotid angiogram. Immediate aspiration of intraventricular hematoma and ventricular drainage were performed bilaterally by a frontal approach. After the operation she recovered consciousness dramatically, and on the following morning she had a clear consciousness. One week later ventriculo-peritoneal shunt was performed. There were no episodes of abnormal bleeding in her past or her family histories. But a prolonged bleeding time was recognized by a routine laboratory examination on admission. The clotting time, platelet count and prothrombin time were normal. As further hemostatic study and factor VIII assay demonstrated the decreased platelet retention rate (Saltzman test), the decreased ristocetin induced platelet aggregation rate (RIPA), and the decreased levels of Coagulant factor VIII (VIII: C), factor VIII-related antigen (VIIIR: AG) and von Willebrand factor (VIII: WF), she was diagnosed as von Willebrand's disease. Fortunately we could perform the operation safely and did not experience the troublesome postoperative bleeding without specific therapy. She was discharged one month later with no neurological deficits and returned to her normal life.

Basal Ganglia Diseases↗
PubMed1983

[Experimental study of cerebral protective substances in ischemia--effect of vitamin E].

Using the "Canine model of complete ischemic brain regulated with a perfusion method", the effects of vitamin E which acts as an antioxidant on cerebral ischemia were investigated. After pretreatment with vitamin E by oral or intravenous administration, cerebral blood flow was reduced to 1/10 the normal state and one hour later, return to a normal state allowed. Subsequent changes in electrical activity were observed and the effects of the vitamin E were evaluated. In the control group, no recovery of electrical activity was seen. While in the group of vitamin E administration, the survival time was not prolonged but the recovery time was shortened statistically in the dogs given 30 mg/kg of vitamin E intravenously. Furthermore, in the group treated with vitamin E, distinct recovery of EEG potentials at three hours after recirculation was apparent. These effects were more favorable in the case of intravenous administration than in the case of oral administration. These experimental results indicated that administration of vitamin E is effective in protecting the brain from cerebral ischemia.

Administration, Oral↗
PubMed1981

Experimental study of new cerebral protective substances - functional recovery of severe, incomplete ischaemic brain lesions pretreated with mannitol an fluorocarbon emulsion.

Using the "canine model of complete ischemic brain regulated with a perfusion method" in which it is possible to control the degree of blood flow to a cerebral hemisphere via a perfusion pump, the effects of mannitol (which acts as a free radical scavenger) and fluorocarbon emulsion (FC) (which has 0.1 micron of average particle size and a high oxygen-carrying capacity) on cerebral ischaemia were investigated. After pretreatment with the drugs, blood flow was reduced via the pump to 1/10 the normal state and 1 hour later, return to a normal state allowed. Subsequent changes in electrical activity were observed and the effectors of the drugs evaluated. In the control group, no recovery of electrical activity was seen, but in the animals treated with either mannitol or FC, incomplete, yet distinct recovery was apparent. In the animals administered mannitol together with FC, however, marked recovery was evident. These experimental results indicate that the combined administration of mannitol and FC is effective in protecting the brain from cerebral ischaemia.

Animals↗
PubMed1981

Subdural effusion following radical surgery for chiasmal region tumors in children. Report of 4 cases.

4 cases of subdural effusion occurring after radical surgery for chiasmal region tumors in children are reported. The pathogenetic mechanisms of this disorder are explained at least partly by a change from internal to external hydrocephalus or brain atrophy in 2 of the 4 cases, whereas the pathogenesis is unclear in the remaining 2 cases. In all 4 cases meningitis did not supervene postoperatively. The subdural effusion may be divided roughly into two types according to symptomatology: "serious type' which presents with severe symptoms and "mild type' which is virtually asymptomatic. The serious type requires immediate surgical procedure, such as continuous subdural drainage and subduroperitoneal shunt, while the mild type should be carefully monitored for the course of subdural effusion by CT scan.

Adolescent↗
PubMed1981

Preservation of the olfactory tract in bifrontal craniotomy for anterior communicating artery aneurysms, and the functional prognosis.

Results of surgical treatment of anterior communicating artery aneurysms, approached via bifrontal craniotomy, are reported in 110 cases. It was possible to preserve the olfactory tracts bilaterally or unilaterally in over 65% of these cases: 47% with bilateral preservation and 34% with unilateral preservation; 33% of the patients with bilateral olfactory tract damage reported subjectively normal olfactory. Objective examination of olfaction by an otolaryngologist showed that 84% of the patients reporting normal olfaction did indeed have normal olfaction, whereas 91% of these reporting no olfaction were anosmic.

Adolescent↗
PubMed1981

[Development of new methods in suppressing brain infarction--combined administration of mannitol and perfluorochemicals (author's transl)].

Various therapeutic methods have been attempted for cerebral infarction, but the development of more effective methods is still awaited. We have investigations of the effect of mannitol in preventing the development of cerebral infarction and have reported it effects in clinical cases of operated cerebral aneurysms. In recent years, our attention has been drawn to the so-called red cell substitute, perfluorochemicals (FC), which has a high oxygen-carrying capacity and a small particle less than 0.1 mu. In the present studies, using infarction models in dogs which have previously developed and reported, observations are made on recovery of brain electrical activity in severe ischemia, suppressing brain swelling following recirculation of cerebral blood flow and protection upon the hemorrhagic brain infarction, due to administration of mannitol or FC. These experimental results indicate that the combined administration of mannitol and FC is effective in protecting the brain from cerebral ischemia.

Animals↗