Biomedical subjects

F Akai

Publications and source records attributed to F Akai.

At least 19 recordsLinked to original sources

PubMed2001

[Dissecting aneurysm of the anterior cerebral artery with later development of collateral circulation: a case report].

Intracranial dissecting aneurysm (DA) is much less frequent than berry aneurysm. Such dissection involves mostly the vertebral and basilar arteries, followed by the internal carotid and middle cerebral arteries. DA of the anterior cerebral artery (ACA) is relatively rare and little is known about its natural Development. Only 23 cases have been reported previously. Our present patient, a 44-year-old man, suddenly developed paresis of the left leg while bathing. Diffusion magnetic resonance imaging indicated an area of high signal intensity in the territory of the ACA. Angiography on day 3 following onset showed a DA involving the left A2 segment. Antiplatelet therapy was administered. Further luminal narrowing in the lesion was demonstrated by repeat angiography on day 17. Occlusion of the distal A2 segment was demonstrated together with sufficient collateral supply on day 41. Symptoms resolved completely. DA of the ACA usually presents with ischemic attacks. Its etiology remains uncertain, and its natural course is unclear. Surgical intervention is recommended for patients with intracranial hemorrhage, while non surgical therapies have achieved good outcomes in ischemic cases.

Adult↗

PubMed1999

[Four cases of abducens palsy caused by a vascular lesion of the vertebrobasilar system].

Several pathological conditions are responsible for abducens palsy, but a lesion of the vertebral artery (VA) has rarely been recognized as one of the causes. It has been reported that a high percentage of cases of abducens palsy are involved with ruptured dissecting aneurysms of the VA. We investigate the vertebrobasilar anatomy in 4 patients, suffering with abducens palsy. One patient revealed a fusiform dilatation of the vertebral artery on the same side as the abducens palsy. Three patients were noted to have stenosis of the vertebral artery from the origin of the posterior inferior cerebellar artery (PICA) to the union. Finally, four patients were found to have abnormal vertebrobasilar anatomy, which was on the same side as the abducens palsy. It is conceivable that changes of vertebrobasilar circulation may cause abducens palsy through direct compression, or ischemic events.

Abducens Nerve↗

PubMed1999

[A case of peduncular hallucination after aneurysmal subarachnoid hemorrhage].

We reported a case of peduncular hallucination after aneurysmal subarachnoid hemorrhage (SAH). The patient underwent endovascular embolization of an intracranial aneurysm using the Guglielmi detachable coils (GDCs) 9 days after SAH. On the 11th day, she reported visual hallucination: a maggot was on the ceiling, or a soldier who wore green clothes was standing by a locker. The hallucination was vivid, well-formed and associated with insomnia, suggesting peduncular hallucination. A computed tomographic (CT) scan revealed small infarctions of right frontal lobe, which were not responsible for the visual hallucination. Hyperdynamic therapy relieved the visual hallucination 23 days after SAH. It was conceivable that vasospasm was the cause of the infarction and visual hallucination. Only 4 cases with peduncular hallucination after SAH were reported in conjunction with vasospasm. The symptom may be concealed by disturbance of consciousness. Visual hallucination should be considered as a sign of cerebral vasospasm, and an appropriate treatment should be done at right time.

Aged↗

PubMed1999

[A case of neurofibromatosis type 1 associated with arteriovenous fistula caused by re-bleeding of a vertebral dissecting aneurysm].

We described a dissecting aneurysm of the vertebral artery (VA), which was associated with neurofibromatosis type 1 (NF1). A 41-year-old man was referred to our hospital because of abrupt, severe headache. A CT scan revealed diffuse subarachnoid hemorrhage (SAH) predominantly in the prepontine cistern. The angiograms showed a string sign in the left VA, just distal to the posterior inferior cerebellar artery (PICA). The vertebral dissection was considered responsible for SAH, and endovascular occlusion of the left VA was attempted. During the intervention, the patient complained of severe neck pain at the time of selective vertebral angiography, which revealed an arteriovenous fistula. The VA was occluded proximal to the PICA with GDC, which covered the fistula. Open surgery confirmed the two unruptured aneurysms. Intracranial dissection is rarely reported in association with NF1. However, ateriovenous fistula is not an uncommon combination with dissecting aneurysm and the extracranial segment of the VA is a characteristic target. Anatomical feasibility is conceivably the pathogenesis.

Adult↗

PubMed1998

Single stranded DNA as an immunocytochemical marker for apoptotic change of ischemia in the gerbil hippocampus.

The light and electron microscopic localizations of single stranded DNA (SSD) protein, a marker of apoptosis and programmed cell death, in the gerbil hippocampus were examined by immunocytochemistry after transient brain ischemia. SSD-immunoreactive (IR) cells appeared from post-operative day 1 (PO 1) to PO 7 after 5- or 10-min ischemia. Immunoreaction was recognized in the nucleus of the CA1 pyramidal neurons without remarkable morphological changes on PO 1. These findings suggest that SSD degradation can occur during delayed neuronal death in the CA1, preceding the appearance of double strand breaks, one of the characteristic features of apoptosis.

Animals↗

PubMed1997

Neuronal integrity and astrocytic reaction in cold injury: an immunohistochemical investigation.

The relationship between extravasation of serum albumin and damage to the neuronal elements as well as the astrocytic reaction was investigated following cold injury, using immunohistochemistry for albumin, microtubule-associated protein I and II (MAPs) and glial fibrillary acidic protein (GFAP). After 30 min, spreading of albumin to the neuropil and uptake into nerve cell bodies and dendrites were clearly observed in the area surrounding the cold lesion. Extravasation of albumin was maximal at 24 h and extended to the ipsilateral hippocampus and thalamus as well as to the paramedian part of the contralateral cerebral hemisphere. Uptake of albumin was seen in neurons with and without loss or reduction of the reaction for MAPs, but the former was confined to the area surrounding the cold lesion. When extravasated albumin receded from the neuropil, the positive reaction for albumin also disappeared from the neuronal elements and those neurons recovered immunoreactivity for MAPs. Astrocytes immunopositive for albumin were observed at 24 h in the white matter, and reactive astrocytes became notable even in the gray matter surrounding the cold lesion. Although reactive astrocytes persisted even after resolution of cerebral edema, immunopositivity for albumin disappeared from astrocytes soon after the disappearance of the reaction from the neuropil. As to the mechanism, rapid endo- and exocytosis may take place in response to the amount of edema fluid in the surrounding extracellular space, where albumin may be eliminated through the transvascular route and/or via the cerebrospinal fluid space.

Animals↗

PubMed1997

[A case of olfactory neuroblastoma with intracranial, intraorbital extension and multiple metastases].

A 51-year-old man presented with headache, vomiting and exophthalmus. Neurological examination revealed anosmia, papilledema, decrease in visual acuity, and disability in ocular movement. MRI showed a huge mass which occupied the whole nasal cavity and compressed the frontal lobe upwards and the eyes laterally. CT revealed an extensive bony destruction of the frontal base and bilateral orbits. The mass was biopsied transnasally, and was histologically diagnosed as olfactory neuroblastoma. It was highly radiosensitive and disappeared with a local irradiation of 40 Gy. Three months later the patient complained of a pain radiating from the neck to the right arm. MRI demonstrated a metastasis at the vertebral body of C5. Local irradiation of 30 Gy was performed. The metastatic lesion was removed, and a bone graft taken from the iliac bone was transplanted via an anterior cervical approach. Three weeks later, however, a hard mass appeared in the right of his neck and was surgically removed. By histological examination, it was also identified as a metastatic neuroblastoma to the cervical lymph node. A week after the removal of the cervical metastatic lesion, the metastasis extended rapidly to the left cervical and the bilateral hilar lymph nodes of the lungs. Chemotherapy was performed with a total doses of 800mg of cyclophosphamide, 1.5mg of vincristine, 40mg of pirarubicin, and 80mg of cisplatin. The lesions disappeared within 7 days. However, the patient died from disseminated intravascular coagulation 10 months after the onset. Olfactory neuroblastoma is usually an intranasal neoplasm, but it rarely extends intracranially and intraorbitally as is shown in our case. Basically, olfactory neuroblastoma is a relatively slow-growing tumor though it has a tendency to develop local recurrences over long periods even after aggressive primary treatment, and accompanied with distant metastases. However, our patient showed a very short survival time. Invasive extension and multiple metastases occurred during a short period, followed by disseminated intravascular coagulation. Combined chemotherapy at the initial treatment may be recommended in such an extensive case.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

Monitoring of cerebrospinal fluid pressure during embolization of AVM.

We experienced that therapeutic embolization of a large cerebral arteriovenous malformation (AVM) led to venous outflow obstruction resulting in intracranial hypertension in a patient who had undergone external decompression. To evaluate hemodynamic changes after embolization, we monitored the cerebrospinal fluid pressure in the next four patients who underwent endovascular treatment. The embolization of a medium AVM resulted in a slight increase in the cerebrospinal fluid pressure. In two medium AVMs, embolization produced slight decreases in the cerebrospinal fluid pressure. In a small AVM, we did not observe any changes in the cerebrospinal fluid pressure during the endovascular treatment. We discuss the mechanism of changes in the intracranial pressure after embolization and conclude that monitoring of the cerebrospinal fluid pressure immediately yields useful information for hemodynamic changes during endovascular treatment.

Adult↗

PubMed1996

Asymptomatic hypothalamic hamartoma associated with an arachnoid cyst--case report.

A 42-year-old male presented with the complaint of mild left facial numbness. Magnetic resonance imaging demonstrated a solid tumor in the interpeduncular cistern and a huge arachnoid cyst in the left middle cranial fossa. The tumor appeared isointense to the surrounding cerebral gray matter on T1-weighted images and hyperintense to that on T2-weighted images. The tumor was partially resected. Histological findings were characteristic of hamartoma. The mild left facial numbness was probably due to compression of the left trigeminal nerve by the arachnoid cyst. Asymptomatic hypothalamic hamartomas may occur in adults with atypical clinical presentations.

Adult↗

PubMed1996

Traumatic subarachnoid hemorrhage as a predictable indicator of delayed ischemic symptoms.

This report provides findings of an investigation of the influence of traumatic subarachnoid hemorrhage on the development of delayed cerebral ischemia caused by vasospasm. The authors prospectively studied 130 patients with closed-head trauma, who exhibited subarachnoid blood on admission computerized tomography (CT) scans. Ten (7.7%) of these patients developed delayed ischemic symptoms between Days 4 and 16 after the head injury. They consisted of three (3.0%) of 101 patients with small amounts of subarachnoid blood and seven (24.1%) of 29 patients with massive quantities of subarachnoid blood on admission CT scans. In each of the 10 patients, severe vasospasm was demonstrated by angiography performed soon after development of ischemic symptoms. There was a close correlation between the main site of the subarachnoid blood and the location of severe vasospasm. In seven of the patients, follow-up CT scans showed development of focal ischemic areas in the cerebral territories corresponding to the vasospastic arteries. These results demonstrate that traumatic subarachnoid hemorrhage, especially if massive, is a predictable indicator of delayed ischemic symptoms.

Adult↗

PubMed1995

A new animal model of cerebral infarction: magnetic embolization with carbonyl iron particles.

A new animal model of cerebral infarction was developed by magnetic embolization with carbonyl iron particles. An electromagnet was placed upon the lateral portion outside the orbit of Mongolian gerbils and charged with a current intensity of 2 A, 3 V (400 G) for 10 min. By intracardiac injection of iron particles at the beginning of the electric charge, infarction was selectively produced in the cerebral cortex. Two days after the operation, microhemorrhaging was seen in the necrotic region. Multiple scattered infarctions accompanied with microhemorrhagic signs closely resembled embolic infarction encountered in the human brain.

Animals↗

PubMed1994

Remote subarachnoid haemorrhage in the posterior fossa following supratentorial surgery. Clinical observation of 6 cases.

Haemorrhage in regions remote from the site of following intracranial operations is rare, but they do occur. We performed supratentorial craniotomy on 639 patients between the time of introduction of computed tomography (CT) for clinical use in 1983 and June 1992; subarachnoid haemorrhage (SAH) in the posterior fossa occurred postoperatively in six of these cases. These included four patients with tumours in the sellar region, one with an arteriovenous malformation (AVM) and one who underwent superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis. The ages of the six patients ranged from 17-72 years. Haemorrhage occurred on the day of operation in one case and was detected on CT examination on the day following surgery in the remaining five cases. Of three patients with disturbance of consciousness, two underwent suboccipital craniectomy for reduction of intracranial pressure, while one received barbiturate therapy and later underwent cerebrospinal fluid (CSF) shunt surgery. No special treatment was necessary for the remaining three patients with less serious lesions. Five of the six patients ultimately recovered their pre-operative neurological status apart from the primary diseases. Factors inducing such haemorrhages seem likely to include displacement of the cerebellum by reduced CSF pressure during and after operations, and stretching and tearing of the veins and venules in the sulci of the tentorial surface of the cerebellum. Consideration should therefore be given to the maintenance of an appropriate CSF pressure during operation; this is particularly important in elderly patients and those with an atrophied cerebral cortex.

Adolescent↗

PubMed1994

Interstitial chemotherapy with biodegradable ACNU pellet for glioblastoma.

For patients with nonresectable glioblastoma (GB) or recurrent GB, we have recently been using an interstitial chemotherapy with biodegradable polylactic acid pellets containing nimustine chloride (ACNU), in combination with superselective arterial ACNU injection, routine irradiation and chemotherapy. The ACNU pellets are prepared by mixing polylactic acid powder and ACNU, and then melting the mixture at low temperature and moulding it into a thin pellet. Pharmacological anticancer activity was experimentally demonstrated by the finding that a region of suppression was present surrounding an ACNU pellet placed in a B6 melanoma cell culture disc, but that no such suppression was present around a control pellet. In order to determine the spatial and temporal distribution of ACNU, a small pellet (ACNU: 0.6 mg) was implanted in the frontal lobe of rats. ACNU concentration determined by HPLC was 61.0 micrograms/g brain tissue on day 1. 22.5 on day 3, and 5.5 on day 7; small amounts of ACNU were in fact released for at least 4 weeks after implantation. This pellet was used for the clinical treatment of 11 GB patients. Four patients had several pieces of pellets implanted immediately after CT-guided stereotactic biopsy, and the other 7 had pellets placed in residual tumor after partial removal at craniotomy. No ACNU was detectable in serum. CT studies obtained at subsequent appropriate intervals disclosed gas formation around the pellets, a slight increase in edema, and necrosis or decrease in CT enhancement of tumor beginning around day 12 after implantation. Bone marrow suppression did not occur, since ACNU was administered interstitially and in the range of 50-200 mg (average: 126 mg) per patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Identity of the dorsal hippocampal region most vulnerable to cerebral ischemia.

Our previous investigations demonstrated that neurons in the area between the subiculum and the medial CA1 region and another area between the lateral CA1 and the CA3 region of the hippocampus are very vulnerable to cerebral ischemia in gerbils, where irreversible damages have been observed occur as early as 4-5 min after unilateral or bilateral common carotid artery occlusion. The present study was aimed to characterize these areas anatomically by using the immunohistochemical and zinc histochemical as well as Golgi silver impregnation methods. Our results indicated that these two areas which are topographically apart on the coronal section actually had a common origin in the rostral part of the hippocampus and that they were separated by insertion of the Ca1 neurons between them in the more caudal part of the hippocampus. The distribution pattern of mossy fibers indicated that these areas belonged to the CA2 region. The double immunohistochemical and zinc histochemical procedure confirmed that these areas developed ischemic lesions promptly even without reperfusion but that the CA1 region did not develop similar lesions until after reperfusion for 12-24 h if the ischemic period was brief. While the reason for the observed susceptibility of the CA2 region is not certain at the present time, it is important to distinguish the ischemic lesions in the CA2 region from those in the CA1 and CA3 regions.

Animals↗

PubMed1993

Manganese superoxide dismutase content and localization in human thyroid tumours.

Manganese-containing superoxide dismutase (Mn-SOD) content and its immunohistochemical localization in human thyroid tumours and some other thyroid diseases were examined and compared with adjacent normal thyroid tissue. Enzyme-linked immunosorbent assay (ELISA) was used in this study for the measurement of Mn-SOD. The content of Mn-SOD tended to increase in diffuse hyperplasia, adenomatous goitre, and follicular adenoma. In papillary carcinoma, it was significantly higher than in adjacent normal thyroid tissue. Follicular carcinoma also revealed a markedly high Mn-SOD content. In the immunohistochemical study, adjacent normal thyroid tissue showed granular positive staining of Mn-SOD in the cytoplasm. An increase of Mn-SOD was observed in the papillary proliferative lesion of diffuse hyperplasia and in the follicles adjacent to lymphoid tissue in chronic thyroiditis with hypothyroidism. Strong positive staining of Mn-SOD was observed in papillary and follicular carcinomas, whereas in anaplastic carcinoma staining was markedly less intense. These results indicate that the Mn-SOD content varies according to the degree of differentiation of thyroid carcinomas.

Adenoma↗

PubMed1993

[Changes in myocardial metallothionein on isoproterenol-induced myocardial injury].

The amounts of myocardial metallothionein (MT) and heavy metal (Zn, Cu) levels during the early stage of the experimental myocardial infarction model induced by isoproterenol (Isp) administration were measured by an atomic absorption spectrophotometry. MT was measured by the Cd-hem method. Myocardial infarction was induced by the administration of 75 mg/kg i.p. of Isp to rats weighing 270 +/- 10 g. Thirty minutes after Isp injection, Zn and Cu levels began to decrease and 12 h later, reached the minimal values compared with the control value. The level of MT began to increase 3 h after the Isp injection and reached the maximal value at 12 h, although MT remained undetectable in the control myocardial tissue by the Cd-hem method. MT levels in the liver increased and total Zn and Cu were elevated compared with the control value 12 h after Isp administration. These results suggest that MT is produced in the myocardium after Isp administration, and that the roles of MT in the heart and the liver are different. It was thought that a rise in MT was induced for the protection of the myocardial cells to injury.

Animals↗

PubMed1993

Morphological properties of human thyroid tumor cells in collagen gel culture and metastatic or invasive ability.

Using normal human thyroid cells and tumor cells, the reconstruction of various diseased cells in collagen gel as well as the relationship between the morphology of colonies in collagen-embedded culture and the biological behavior (benignity, malignancy, metastasis, and invasion) of the original tumors were studied. In collagen gel culture, normal thyroid cells reorganized follicle-like constructions, and follicular adenoma cells showed in vivo-like constructions. However, two different types of colonies were observed in cultures of cells from papillary carcinomas. One was the branching type with many outgrowths projecting to three dimensions and the other was the spherical type without any outgrowths. These spherical colonies were observed in all cases of papillary carcinoma, but varied from one case to another. Metastasis and invasion were detected during pathological examination in cases with a high ratio of spherical colonies. Our results indicate that cells from highly metastatic and invasive thyroid cancer form spherical colonies in the collagen gel culture, and that this collagen culture is a useful method for studying the heterogeneity of tumor cells as well as the metastasis and invasive ability of tumor cells in vitro.

Adenoma↗

PubMed1992

Intracerebral distribution of albumin after transient cerebral ischemia: light and electron microscopic immunocytochemical investigation.

The blood-brain barrier breaks down following cerebral ischemia, but the exact sequence of events for extravasation of serum proteins and their parenchymal distribution remain uncertain. We studied the distribution of serum albumin in the hippocampus of the gerbil brain using light and electron microscopic immunocytochemical techniques. With light microscopy, there was no reaction for albumin for the first 12 h after unilateral common carotid artery occlusion for 10 min and reperfusion. At 12 h, the reaction was weak and limited to the neuropil in the subiculum-CA1 region (between the subiculum and the medial CA1 region). After 24 h, the reaction became intense in the neuropil and neuronal perikarya in the subiculum-CA1 and medial CA1 regions. The electron microscopic immunocytochemical study of the subiculum-CA1 and medial CA1 regions revealed electron-dense immunoprecipitates in the extracellular space and the peripheral part of the apical dendrites as early as 30 min after reperfusion and in the astrocytic cytoplasm after reperfusion for 1 h. However, immunoprecipitates were not found in the neuronal perikarya until after reperfusion for 24 h. The present study demonstrated prompt appearance of albumin in the extracellular space of the brain parenchyma after re-establishment of cerebral circulation and prompt accumulation in the peripheral part of the dendrites with spreading to neuronal perikarya, likely in the process of degeneration and death.

Animals↗