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Tohru Kamida

Publications and source records attributed to Tohru Kamida.

At least 19 recordsLinked to original sources
PubMed2006

Induced angiogenesis under cerebral ischemia by cyclooxygenase 2 and hypoxia-inducible factor naked DNA in a rat indirect-bypass model.

We recently reported that hypoxic stress induces the expression of HIF-1alpha, HIF-2alpha, cyclooxygenases-2 (COX-2) and VEGF in vivo. In this study, we investigated whether HIF-1alpha, HIF-2alpha, or COX-2 naked DNA induced angiogenesis in a cerebral ischemic model in vivo. We utilized a rat encephalo-myo-synangiosis (EMS) model and inoculated naked DNA into the brain surface. We analyzed whether DNA induced angiogenic factors and neovascularization. New blood vessel formation was detected by anti-Factor VIII staining. A histological section treated with HIF-2alpha or COX-2 DNA showed an increased expression of VEGF with angiogenesis, in comparison to the control DNA. The HIF-1alpha, HIF-2alpha, and COX-2 are able to promote significant angiogenesis development. These results suggest the feasibility of a novel approach for therapeutic angiogenesis of cerebral ischemia in which neovascularization may be indirectly achieved using a transcriptional and cytokine's regulatory strategy.

Animals↗
PubMed2006

Benign pleomorphic astrocytoma in the hypothalamus--case report.

A 41-year-old woman presented with an unusual case of benign astrocytoma with marked pleomorphism manifesting as consciousness disturbance due to intraventricular hemorrhage. Magnetic resonance imaging revealed a well-enhanced hypothalamic mass protruding into the third ventricle. Despite partial resection of the tumor without additional therapy, there have been no signs of tumor regrowth for 6 years. The histological findings revealed solid proliferation of tumor cells with marked pleomorphism, contrary to the benign clinical course. However, no mitosis, necrosis, or endothelial proliferation were found and the MIB-1 index was less than 0.5%. Immunohistochemical staining indicated the glial origin of the tumor. The tumor was similar to pleomorphic xanthoastrocytoma, but the histological findings were not exactly identical, indicating a new histological entity.

Adult↗
PubMed2006

Intraoperative corticomuscular motor evoked potentials for evaluation of motor function: a comparison with corticospinal D and I waves.

OBJECT: The goal of this study was to compare motor evoked potentials recorded from muscles (muscle MEPs or corticomuscular MEPs) with corticospinal MEPs recorded from the cervical epidural space (spinal MEPs or corticospinal MEPs) to assess their efficacy in the intraoperative monitoring of motor function. METHODS: Muscle and spinal MEPs were simultaneously recorded during surgery in 80 patients harboring brain tumors. Each case was assigned to one of four groups according to final changes in the MEPs: (1) Group A, in which there was an increased amplitude in the muscle MEP with an increased 13 wave amplitude (12 cases); (2) Group B, in which there was no significant change in the MEP (43 cases); (3) Group C, in which there was a decreased muscle MEP amplitude (< 35% of the control) with a decreased I wave amplitude but an unchanged D wave (15 cases); or (4) Group D, in which there was an absent muscle MEP with a decreased D wave amplitude (10 cases). In patients in Group A, the increase in the amplitude of the muscle MEP (range of increase 128-280%, mean increase 188.75 +/- 48.79%) was well correlated with the increase in the 13 wave in corticospinal MEPs. Most of these patterns were observed in patients harboring meningiomas (10 [83.3%] of 12 cases). Patients in Group B displayed no changes in muscle and corticospinal MEPs and no signs of postoperative neurological deterioration. Patients in Group C showed a substantial decrease in the amplitude of the muscle MEP (range of decrease 5.3-34.8% based on the control waveform, mean change 21.81 +/- 10.93%) without deterioration in the corticospinal D wave, and exhibited severe immediate postoperative motor dysfunction. This indicates dysfunction of the cortical gray matter, including the motor cortices, which are supposed to generate I waves. Patients in Group D exhibited decreases in the corticospinal D wave (range of decrease 21.5-55%, mean decrease 39.75 +/- 11.45%) and an immediate cessation of the muscle MEP as well as severe permanent motor paresis. CONCLUSIONS: These results indicate that, during surgery, monitoring of corticomuscular MEPs (which are related to I waves) is a much more sensitive method for the detection of immediate motor cortical damage than monitoring of corticospinal MEPs (D wave).

Adolescent↗
PubMed2005

Geranylgeranylacetone limits secondary injury, neuronal death, and progressive necrosis and cavitation after spinal cord injury.

This study evaluates the neuroprotective effects of geranylgeranylacetone (GGA), which is known as an antiulcer agent and more recently as a heat-shock and other neuroprotective protein inducer, on secondary degeneration after spinal cord injury in rats. Crush injuries were produced at the T8 level using an extradural approach. Optimal administration conditions of GGA were established in an initial experiment by evaluating the appearance of lesions 24 h after injury in sections stained with H-E. Then, in a second experiment, animals treated with the optimal condition (600 mg/kg, 24 h before injury and thereafter every 24 h) were allowed to survive for 6 and 24 h and 1, 3, and 8 weeks after injury, and spinal cords were prepared for histological evaluation by staining for H-E for general histopathology and by silver staining for axons. There was a significant reduction (46%) in lesion volume 24 h after injury in animals treated with optimal administration conditions. The increase in tumor necrosis factor-alpha (TNF-alpha) and the accumulation of neutrophils in the damaged segment of the spinal cord 4 h after injury were significantly inhibited in animals that received GGA. Lesion size and cavitation area remained smaller in treated animals throughout the post-injury survival interval. These results suggest that GGA administration significantly reduces the secondary degeneration that would otherwise occur. The mechanism by which GGA exerts its beneficial effect is unknown but may involve reduction of TNF-alpha activation at the injured cord and/or inhibition of inflammation.

Animals↗
PubMed2005

Stereotactic radiosurgery for recurrent pleomorphic adenoma invading the skull base--case report--.

A 38-year-old man presented with a recurrent pleomorphic adenoma in the parapharyngeal space invading the skull base 19 years after the first operation for a parotid gland tumor. Stereotactic radiotherapy was performed to control the tumor growth using a marginal dose of 8 Gy and maximum dose of 18 Gy with care taken to minimize the dose to nearby structures. The symptoms were reduced within a few months. Magnetic resonance imaging over 5 years showed that the tumor was controlled with no regrowth. Stereotactic radiotherapy is a therapeutic option for the treatment of pleomorphic adenomas.

Adenoma, Pleomorphic↗
PubMed2004

Long-term effects of indirect bypass surgery on collateral vessel formation in pediatric moyamoya disease.

OBJECT: The authors investigated whether revascularization surgeries in children with moyamoya disease could reduce abnormal collateral formations in the posterior circulation; long-term follow-up angiography was performed to assess status. METHODS: In six patients who underwent indirect bypass surgery in childhood, long-term follow-up angiography studies were obtained between 7 and 12 years after surgery. All six patients presented with ischemic symptoms at onset of disease between 2 and 7 years of age. Ischemic insults did not occur after surgery in any patient. In five cases, the angiographically documented stages advanced bilaterally, and in three cases the angiography revealed nearly occluded intracranial carotid arteries bilaterally. In all sides in these five cases, the collateral circulation through the grafts developed well, and collateral formation from the lenticulostriate arteries and from the anterior choroidal artery decreased according to the natural advancement of disease. There was no reduction in the collateral formations from the posterior circulation, however, in four of these five cases. CONCLUSIONS: Although the data cannot directly indicate that the patients in this study remain at potential risk of developing hemorrhage in the future, these facts should be considered when evaluating the efficacy of revascularization surgeries, because the hemorrhagic potential of abnormally dilated collateral vessels from the posterior circulation would increase as the advancement of the disease.

Brain↗
PubMed2003

Chronic intraventricular encapsulated hematoma presenting unique radiological features: a case report.

BACKGROUND: Chronic encapsulated hematoma is relatively rare and the exact mechanisms of this condition remain uncertain. In this report, we present a case of chronic encapsulated hematoma in the lateral ventricle and discuss the pathophysiology of this condition. CASE DESCRIPTION: A 68-year-old-woman presented with progressive gait disturbance. Magnetic resonance imaging (MRI) showed a dumbbell-shaped mass arising from the wall of the right lateral ventricle. The mass connecting to the ventricle wall mimicked a hemorrhagic tumor and the other part mimicked a cystic mass. Cerebral angiography demonstrated arteriovenous shunt in the right lateral ventricle wall. The operative findings revealed that the part arising from the ventricle wall contained hematoma showing various stages of coagulation and that the cystic mass visible on MRI was a granulomatous solid mass. Histologic examination revealed that the capsules of both were compatible with chronic encapsulated intracerebral hematomas. CONCLUSION: In the present case, one part of the mass contained only granulomatous tissue, indicating the possibility that the mass was undergoing spontaneous resolution. This fact might indicate that the presence of neo-vascularization in the capsule is not the sole factor in the expansion of hematoma.

Aged↗
PubMed2003

Significance of leptin expression in invasive potential of pituitary adenomas.

We immunohistochemically examined the expression of leptin in pituitary adenomas to investigate the correlation between the invasiveness of tumours and leptin expression. The subjects consisted of 79 patients with pituitary adenoma and were classified into the following groups: (1) non-functioning adenomas; (2) GH-secreting adenomas; (3) prolactinomas; (4) ACTH-secreting adenomas; (5) others (LH, FSH or TSH-secreting adenomas). Thereafter all cases were subdivided according to the size of tumour and the presence of invasion to the surrounding tissue. Among non-functioning adenomas, there was no significant difference between invasive and non-invasive non-functioning adenoma. In functioning adenomas, a significant difference in leptin expression was noted in intrasellar non-invasive adenomas compared to other adenomas. There was also a significant difference in leptin expression between non-invasive and invasive adenomas regardless of size. These results suggest that leptin has a role in the invasive potential of functioning adenomas.

Adenoma↗
PubMed2003

Usefulness of magnetic motor evoked potentials in the surgical treatment of hemiplegic patients with intractable epilepsy.

Five hemiplegic patients with intractable epilepsy were studied with transcranial magnetic stimulation (TMS) before and after various surgical treatments. These patients had unilateral widespread cerebral lesions acquired at various times, including congenital, infantile and childhood injury. Motor evoked potentials (MEPs) of the abductor pollicis brevis (APB) muscles were simultaneously recorded on both sides following TMS of the motor cortex in the respective hemisphere using a figure-8 or circular coil. In all patients with congenital disease, the abolition of motor function in the affected hemisphere was estimated by magnetic MEPs, and the hemiplegia did not deteriorate after functional hemispherectomy (HS) was performed in two of them. In two patients with acquired disease, HS was not performed because it was shown by magnetic maps that the motor function in the affected hemisphere remained. Furthermore, it was shown by electric MEPs using subdural electrodes that a patient who had had encephalitis in early childhood had a reorganised motor area in the parietal cortex of the affected hemisphere. The present findings indicate that magnetic MEPs are a very useful non-invasive method of assessing whether the motor area in the affected hemisphere can be resected in hemiplegic patients with intractable epilepsy.

Adolescent↗
PubMed2003

Temporal profile of angiographical stages of moyamoya disease: when does moyamoya disease progress?

To elucidate the initiation of Moyamoya disease, we analyzed the progression of angiographical stages in repeated angiographical studies. The clinical subjects consisted of 39 patients. Angiographical stages were classified by the criteria of Suzuki and Takaku. For examinations, conventional cerebral angiography or magnetic resonance angiography was performed. The follow-up period ranged from three months to 17 years. We found the following results. 1. Older patients presented with advanced angiographical stages. 2. Angiographical stages were usually progressive in pediatric patients, while stable in adult patients. In pediatric cases, the disease advanced to stage V within 10 years from the onset in the majority of patients. However, in certain cases the disease progressed after adolescence. 3. Among pediatric patients, certain cases, in whom the onset of the disease was later than five years of age, showed relatively slow progression of angiographical stages. Our data indicate that certain pediatric cases whose disease started after five years of age presented with stable temporal changes in the angiographical stages. These findings might indicate that in only a few adult cases does the disease initiate in adulthood and in the majority of adult patients the disease starts in childhood.

Adolescent↗
PubMed2003

Repetitive transcranial magnetic stimulation for protection against delayed neuronal death induced by transient ischemia.

OBJECT: Data in the present study demonstrate that repetitive transcranial magnetic stimulation (rTMS) induces ischemic tolerance against delayed neuronal death (DND) of hippocampal neurons following an otherwise lethal ischemic insult. METHODS: Various regimens of rTMS were delivered to adult gerbils at various times prior to an episode of ischemia induced by transient (5-minute) bilateral common carotid artery (CCA) occlusion. The extent of DND in the CA1 region of the hippocampus was assessed quantitatively 7 days after the transient ischemic episode. When rTMS was delivered 2 to 5 days prior to bilateral CCA occlusion, DND was substantially attenuated; delivery of rTMS 12 to 24 hours prior to occlusion induced partial tolerance. In the group of animals that had received stimulation 2 days prior to occlusion, neuron density in the CA1 sector was significantly higher (three gerbils, 210.33, 86.01% of normal) than in the group that experienced ischemia only (three gerbils, 10.66, 4.36% of normal). A similar degree of neuron sparing occurred when stimulation was delivered 3, 4, or 5 days prior to occlusion. Note that rTMS was effective when it was delivered at frequencies of 25 and 50 Hz. Stimulation at 25 Hz for 128 seconds (3200 pulses) was more effective than stimulation at 50 Hz for 64 seconds (3200 pulses) or 128 seconds (6400 pulses), however. CONCLUSIONS: Noninvasive rTMS represents an important tool for exploring the mechanisms of ischemic tolerance and preventing ischemic neuronal damage.

Animals↗
PubMed2002

A case of schizencephaly with subdural fluid collection in a neonate.

CASE REPORT: A neonate who had schizencephaly associated with ipsilateral chronic subdural fluid collection in the neonatal period is described. A boy was born to a healthy Japanese woman. After birth, the boy presented with rapid expansion of head circumference. Computed tomography (CT) and magnetic resonance images (MRI) of the head demonstrated left schizencephaly combined with a midline shift attributable to hydrocephalus. Thereafter, the patient gradually presented other symptoms caused by increased intracranial pressure. Ultrasonography and MRI of the head showed the presence of a subdural fluid collection overlaid on the schizencephaly. We identified the outer membrane by burr-hole craniotomy. CONCLUSION: This was a rare case of schizencephaly associated with hydrocephalus and the formation of ipsilateral chronic subdural fluid collection.

Brain↗
PubMed2002

Stereotactic radiosurgery for aggressive papillary tumor of the temporal bone: case report.

BACKGROUND: Papillary tumors of the temporal bone are very rare neoplasms that show locally aggressive behavior though they have low-grade histologic features. The best treatment for these tumors is a radical resection. However, if the tumor is very large, local invasiveness and hypervascularity can prevent surgeons from achieving a complete resection. As an additional treatment for the residual tumor, it remains controversial whether radiation therapy has any role. CASE DESCRIPTION: The authors describe a 53-year-old woman who suffered from left-sided tinnitus, hearing loss, and diplopia due to a large aggressive papillary tumor of the temporal bone. Radiosurgery was very effective for the tumor, which had regrown a few years after conventional radiation therapy and chemotherapy. CONCLUSIONS: The authors conclude that radiosurgery should be considered as an option for the treatment of aggressive papillary tumor of the temporal bone.

Carcinoma, Papillary↗
PubMed2002

Effects of indirect bypass surgery for occlusive cerebrovascular diseases in adults.

The efficacy of indirect bypass surgery on hemodynamics in elderly adults with occlusive/stenotic cerebrovascular disease was retrospectively investigated in five elderly patients. Three cases were diagnosed as quasi-moyamoya disease. One patient was diagnosed with moyamoya disease. Of these four patients, three patients showed marked transdural leptomeningeal anastomosis. All patients showed certain areas of hypoperfusion with impairment of the perfusion reserve in the affected areas. All patients underwent encephalo-duro-arterio-synangiosis (EDAS) unilaterally and were followed up for 1-5 years. Three patients showed improvement of hemodynamic status, all of whom showed spontaneously developed leptomeningeal anastomosis in the preoperative angiographies. In two of these three patients, well-developed collateral formation from the graft was observed angiographically. We speculated that in addition to impaired cerebral perfusion reserve, spontaneously developed leptomeningeal anastomosis might be the key factor for the efficacy of indirect bypass in elderly patients with occlusive/stenotic cerebrovascular disease.

Aged↗
PubMed2002

Sleep cycle in patients in a state of permanent unconsciousness.

Since the recent diagnostic criteria for persistent vegetative state (PVS) require the presence of a sleep-wake cycle, certain patients in similar conditions should be excluded from PVS. Since the diagnosis of PVS might correlate with legal issues, an accurate definition is necessary. To clarify the clinical significance of a sleep-wake cycle, 12 patients in a state of permanent unconsciousness after brain damage were clinically and electrophysiologically reviewed. In addition to routine EEG, evoked potentials and MRI, the simultaneous recordings of EEG and patients by videotape were performed for 24 hours. Four patients who showed severe brain stem damage did not show a sleep-wake cycle. In the other eight patients, a sleep-wake cycle was observed. However, among these patients there was no obvious difference in their clinical status. Although these data suggest that the presence of a sleep-wake cycle might reflect the brain stem damage, it is considered that the presence of a sleep-wake cycle might be unnecessary for the diagnostic criteria for PVS. Further study of various forms of brain damage will provide better understanding of the significance of the presence of a sleep-wake cycle.

Adolescent↗