PubMed Health⌕ Search

Biomedical subjects

Y Yoneoka

Publications and source records attributed to Y Yoneoka.

17 recordsLinked to original sources
PubMed2004

Human Kluver-Bucy syndrome following acute subdural haematoma.

We present a rare case of complete human Kluver-Bucy syndrome (KBS) following recovery from transtentorial herniation caused by acute subdural haematoma (ASDH). A 17-year-old right-handed high school boy got into stupor within five minutes after 3-rounds of sparing at boxing. Emergency computed tomographic (CT) scan showed right cerebral hemispheric ASDH, which was evacuated following intentional decompressive craniectomy. After recovery of consciousness, he developed emotional changes (placidity with loss of normal fear and anger), psychic blindness, aberrant sexual behaviour, excessive oral tendencies, increased appetite, and hypermetamorphosis in order of mention, which were observed with waxing and waning from 17th to 28th hospital day. Peri-operative CT scaning and magnetic resonance imaging showed lesions of the right temporal lobe and right-dominant orbitofrontal regions including bilateral rectal and medial orbital gyri, and the intact left temporal lobe. Two pathogeneses can be thought of and the whole picture of KBS following ASDH can arise even though one (left in this case) temporal lobe is preserved, 1) in which associated orbitofrontal lesions of the frontal lobes may correlate with occurrence of KBS, or 2) cerebral blood hypoperfusion of both temporal lobes due to increased intracranial pressure and/or compression of both posterior cerebral arteries at the edge of the tentorium cerebelli occurs.

Adolescent↗
PubMed2004

Ruptured de novo intracranial aneurysms.

OBJECTIVE: We describe the actual state of ruptured de novo intracranial aneurysms to contribute to a guideline of follow-up for the patients with treated intracranial aneurysm. METHODS: The authors retrospectively investigated 12 cases drawn from 483 consecutive cases of aneurysmal subarachnoid hemorrhage at our institute over a period of 22 years, in which a previously undemonstrated (hence "de novo") intracranial saccular aneurysm formed and ruptured after successful treatment of a prior aneurysm. FINDINGS: The 12 cases constitute 2.5% of the 483 patients who left our hospital alive. Eleven cases were females and one was a male with a mean age of 55.7 years (range 29-75) at the first subarachnoid haemorrhage (SAH) and an interval between the first and the second rupture of 10.7 years (range: 2.6-23.8, standard deviation: 6.86, 95% confidence interval: 6.39-15.1). Four cases did not have risk factors such as hypertension, family history, smoking, multiple aneurysms, and moyamoya disease. None of these ruptured de novo aneurysms was at the same location as the original lesion. One-third (4 cases) of the de novo lesions in our series were found on the opposite side to each prior lesion. INTERPRETATION: For not only young but also elder patients with a treated aneurysm (from the fifth decade to the sixth), especially for women, late angiography or alternative modalities of less-invasive examination should be considered. To detect de novo intracranial aneurysms before rupture, the search for a de novo aneurysm should be performed within 6.39 years after a previous examination that shows an aneurysm to be nonexistent, in view of the 95% confidence interval of the mean time to de novo aneurysmal rupture (6.39-15.1 years). If applied this survey, 75% (8 cases of 12 cases) of our de novo aneurysms would be detected before rupture.

Adult↗
PubMed2002

Pre-operative histopathological evaluation of meningiomas by 3 0T T2R MRI.

BACKGROUND: To assess the potential of T2 reversed (T2R) magnetic resonance imaging (MRI) for the pre-operative histopathological assessment of meningiomas. METHOD: Twenty patients scheduled for meningioma resection were prospectively assessed using T2R MRI on a 3 tesla system. Image characteristics were compared with intra-operative findings and post-operative histopathological examination of excised meningioma tissues. FINDINGS: The averaged T2 characteristics expressed as averaged gray scale levels of the tumour correlated highly with tumour consistency, in agreement with previous reports. Furthermore, detailed evaluation of the structural appearance of tumour on T2R images revealed brightness of tumour (shorter T2) was dependent on the degree of histopathological heterogeneity. Significantly shorter T2 value correlated with collagen-rich fibrous tissue. INTERPRETATION: The study demonstrated the advantage of T2R imaging in pre-operative determination of histopathological characteristics of meningiomas. As a step towards MR microscopy and improved pre-operative treatment planning, T2R imaging on a 3.0 T system appears to play an important role in the non-invasive pre-operative structural assessment of a tissue of interest.

Adult↗
PubMed2001

MRA demonstration of "periarteritis" in Tolosa-Hunt syndrome.

BACKGROUND: Modern magnetic resonance imaging (MRI) diagnosis of Tolosa-Hunt syndrome rests upon demonstration of cavernous sinus abnormalities. We present a case of Tolosa-Hunt syndrome who has no abnormal mass lesion in the cavernous sinuses on MRI but with a diagnostic lesion on magnetic resonance angiography (MRA). CLINICAL PRESENTATION: A 48-year-old woman developed acute periorbital pain and abducens palsy of the right side at the first episode, and subacute peri-orbital pain and rapidly deteriorating visual acuity on the left side at the second episode with a four months interval. MRI showed no soft-tissue abnormality in the cavernous sinuses. FINDINGS: MRA demonstrated a narrowing of the right cavernous carotid artery at the first episode, and narrowings of the left clinoid carotid and ophthalmic arteries at the second episode. Based on these findings, the patient underwent urgent steroid therapy and the symptoms resolved dramatically in each episode. Follow-up MRA confirmed resolution of arterial narrowings. INTERPRETATION: MRA may help prompt the noninvasive diagnosis in certain cases of Tolosa-Hunt syndrome with little inflammatory reaction in the cavernous sinus but with predominant intra- and juxta-cavernous periarteritis.

Cavernous Sinus↗
PubMed2001

Planum temporale: where spoken and written language meet.

Functional magnetic resonance imaging studies on spoken versus written language processing were performed in 20 right-handed normal volunteers on a high-field (3.0-tesla) system. The areas activated in common by both auditory (listening) and visual (reading) language comprehension paradigms were mapped onto the planum temporale (20/20), primary auditory region (2/20), superior temporal sulcus area (2/20) and planum parietale (3/20). The study indicates that the planum temporale represents a common traffic area for cortical processing which needs to access the system of language comprehension. The destruction of this area can result in comprehension deficits in both spoken and written language, i.e. a classical case of Wernicke's aphasia.

Adolescent↗
PubMed2001

High-field magnetic resonance imaging in patients with moyamoya disease.

OBJECT: The purpose of this study was to assess the utility of high-field magnetic resonance (MR) imaging as a quantitative tool for estimating cerebral circulation in patients with moyamoya disease. METHODS: Eighteen patients with moyamoya disease who were scheduled to undergo revascularization surgery and 100 healthy volunteers were examined using T2-reversed MR imaging performed using a 3-tesla system. Ten of the 18 patients underwent a second study between 1 year and 3 years after revascularization. Magnetic resonance images obtained in the patients with moyamoya disease were statistically analyzed and compared with those obtained in healthy volunteers. The MR imaging findings were also correlated with results of single-photon emission computerized tomography and conventional cerebral angiography studies. Transverse lines in the white matter (medullary streaks) were observed in almost all persons. In healthy volunteers, the diameter sizes of the medullary streaks increased significantly with age (p < 0.001). Multiple logistic regression analysis revealed that age-adjusted medullary streak diameters were significantly larger in patients with moyamoya disease (p < 0.001). Diameter sizes also increased significantly with the increased severity of cerebral hypoperfusion (p < 0.001) and a higher angiographically determined stage of the disease (p < 0.001). Diameter sizes decreased significantly after surgery (p < 0.001). CONCLUSIONS: The increases in medullary streak diameters observed in patients with moyamoya disease appear to represent vessels dilated due to cerebral hypoperfusion. High-field T2-reversed MR imaging is useful in estimating cerebral circulation in patients with moyamoya disease.

Adolescent↗
PubMed2001

Central tinnitus: a case report.

We report a case of acute-onset unilateral tinnitus in a 25-year-old woman. Analysis of imaging studies indicated that the tinnitus was likely caused by an acute hemorrhage of a small cavernous angioma that was located adjacent to the contralateral primary auditory cortex. This case provides substantial support for the concept that central tinnitus might indeed represent a pathologic activation of neural networks of nonspecific auditory perception.

Adult↗
PubMed2000

Intrauterine methylmercury intoxication. Consequence of the inherent brain lesions and cognitive dysfunction in maturity.

We studied the effects of intrauterine neurotoxicity by methylmercury (MeHg) on the postnatal developing and adult stages of rats. We used offspring delivered from dams that had been given 1 mg/kg/day methylmercury chloride for 5 pregestational days and throughout pregnancy. Histopathological examination of the brains of a proportion of the offspring on postnatal days 1 (P1) and P3 revealed degenerative neurons in the brain stem and the limbic system, including the hippocampus and the amygdala. At P7 and P14, degenerative neurons were indiscernible, but reactive astrocytosis remained in the brain stem. At P70 and P180, the brains seemed to have developed well. However, in behavioral analyses performed at 6 months of age, MeHg-exposed rats showed a significant learning disability in the passive avoidance response compared with controls, but no differences in water maze performance. Furthermore, morphometric analysis of the amygdala and hippocampus revealed significantly fewer neurons in both areas in the MeHg-exposed rats. Thus, chronic intrauterine exposure to low-dose MeHg induces a decrease in neuron population in the limbic system, and the offspring have impaired higher brain function.

Age Factors↗
PubMed2000

Growth of incidental meningiomas.

The aim of this study was to assess the growth of incidental meningiomas, to establish a strategy for dealing with these tumours. The cases of 37 patients with a meningioma revealed incidentally by computerized tomography or magnetic resonance imaging, who were followed at least once by an additional imaging study, were reviewed. The tumour volume was calculated, to estimate the annual growth rate of the incidental meningiomas. Nine of the 37 patients (24.3%) showed a considerable increase (the annual growth rate > 1 cu cm/year) in their tumour volume (tumour growth). There was no significant difference in the follow-up period, age, or the volume of tumour between the patients with and without tumour growth. However, a multivariate analysis revealed that the likelihood of tumour growth independently and significantly increased according to a decrease in the age of the patients (Odds ratio 0.18 for one-standard-deviation change (ISD) 12.6 years, p = 0.042) and according to an increase in the volume of the tumour (Odds ratio 3.64 for ISD 4.46 cu cm, p = 0.042). The majority of patients with incidental meningioma can be apparently observed without any surgical intervention, because their annual growth rates are generally less than 1 cu cm/year. However, clinical and radiological observations would be advisable for these patients (especially young patients and patients with a large tumour), in view of the presence of rapidly growing tumours in some of the patients.

Adult↗
PubMed1999

Administration of prosaposin ameliorates spatial learning disturbance and reduces cavity formation following stab wounds in rat brain.

The effectiveness of prosaposin as a neurotrophic factor was investigated using rats with bilateral stab wounds, injecting 240 ng per day of prosaposin for 3 days. In Morris water maze task, after 3 weeks postoperation, the stab-wounds rats show significant impairment in acquisition compared with the sham-operated rats. In the transfer test the mean number of crossings of the platform place in stab-wounds was significantly lower than that in sham-operated rats (P < 0.01). The stab-wounds rats treated with prosaposin showed significant improvement (P < 0.05). The cavities following stab wounds in the rats treated with prosaposin were significantly smaller than those in the rats treated with (P < 0.05). Our data support that prosaposin is likely to be a new agent for brain injury.

Animals↗
PubMed1999

An experimental study of radiation-induced cognitive dysfunction in an adult rat model.

The objectives of this study were to establish an adult rat model for the late onset of radiation-induced cognitive dysfunction and to compare behavioural dysfunction with histopathological changes. While under anaesthesia, 30 rats (experimental group) were irradiated with a total dose of 40 Gy, given as eight fractions in 24 days. Another 30 rats (control group) underwent sham irradiation. The cognitive functions of all rats were evaluated at 6, 9 and 12 months after irradiation using the Morris water maze and passive avoidance tasks. Histopathological examination of these rats was carried out after the evaluation of cognitive functions was complete. At 6 and 9 months after irradiation there were no significant differences between the control and irradiated groups in passive avoidance and water maze tests. At 12 months after irradiation, the passive avoidance task revealed a deterioration of cognitive function in the experimental group. Histopathological observations revealed no abnormal findings in the irradiated brains at the light microscope level. Late onset cognitive dysfunction following cranial irradiation was observed in an adult rat model. Pathological investigations showed no abnormalities in the irradiated brains. These findings indicate that radiation-induced cognitive dysfunction can precede morphological changes in the brain or that they arise without them. The present model seems useful for elucidating the pathogenesis of radiation-induced cognitive dysfunction and for developing methods for therapy and prophylaxis.

Age Factors↗
PubMed1998

Ruptured distal anterior choroidal artery aneurysm presenting with casting intraventricular haemorrhage.

This report describes a rare case of a distal anterior choroidal artery aneurysm which developed intraventricular haemorrhage without subarachnoid haemorrhage as shown on computerized tomographic (CT) scan. A 69-year-old hypertensive man suddenly became unconscious. An emergency CT scan showed a severe intraventricular haemorrhage and a small round low-dense lesion within the haematoma at the right trigone. The haematoma with obstructive hydrocephalus made the lateral ventricles larger on the right than on the left. CT scan could not detect any subarachnoid haemorrhage. Right interal carotid angiography revealed a saccular aneurysm at the plexal point of the right anterior choroidal artery. We approached the aneurysm and the small round lesion through the trigone via a right temporo-occipital corticotomy. We could clip the aneurysmal neck and remove the intraventricular haematoma and the papillary cystic mass (corresponding to the small round lesion on CT scan) totally in one sitting. Histological examination revealed the aneurysm to be a true one and the papillary cystic mass to be a choroid plexus cyst.

Aged↗
PubMed1995

Frequent TIA in the territory fed by the anastomosed STA after combined therapeutic ICA occlusion and extracranial-intracranial bypass: case report.

Frequent transient ischaemic attacks (TIAs) in the territory fed by the anastomosed superficial temporal artery (STA) after combined therapeutic internal carotid artery (ICA) occlusion and extracranial-intracranial bypass is described in a 52-year-old woman with a giant aneurysm in the supraclinoid portion of the left ICA showing impairment of visual acuity in the left eye and right upper quadrantanopia. After the balloon test occlusion of the left ICA which was tolerated, the left STA-middle cerebral artery anastomosis was performed and occlusion of the left ICA using detachable balloons was carried out a day later. TIAs corresponding to the territory fed by the anastomosed STA occurred nine times two to four days and five times eight to nine days after the ICA occlusion without new infarction on computed tomography (CT) scan. Single-photon emission computed tomography showed no hypoperfusion immediately after the initial TIA. CT scan revealed thrombosis of half of the aneurysm a day after the ICA occlusion. The patient developed the same TIA as previously by compression of the left anastomosed STA at the time of follow-up angiography which was carried out eight days after the occlusion. Although heparin was continuously administered after the ICA occlusion for two days, the initial TIA occurred during heparinization. Anticoagulation seemed to be inadequate judging from activated coagulation time and incomplete thrombosis of the aneurysm occurred during heparinization. It is likely that the TIAs are caused by embolism via the STA, which is a rare ischaemic complication.

Anastomosis, Surgical↗