Search PubMed⌕ Search

Biomedical subjects

Teiji Tominaga

Publications and source records attributed to Teiji Tominaga.

At least 19 recordsLinked to original sources
PubMed2007

[A case of cavernous angioma at the septum pellucidum].

A 35-year-old female presented with a cavernous angioma of the septum pellucidum manifesting as headache and nausea. Computed tomography and magnetic resonance imaging revealed a mass at the septum pellucidum with intraventricular hemorrhage and mild hydrocephalus. Digital subtraction angiography showed no abnormal finding and thallium-201 single photon emission computed tomography showed no uptake in the lesion. The preoperative diagnosis was intraventricular tumor, such as subependymoma. The lesion was completely resected through the transcallosal approach. The histological diagnosis was cavernous angioma. Cavernous angiomas are usually located in the cerebral parenchyma and rarely occur in the cerebral ventricles. In particular, cavernous angioma at the septum pellucidum is very rare. If magnetic resonance imaging does not clearly show the typical peripheral hypointense rim, neuroimaging diagnosis will be difficult. Surgical resection should be considered to confirm the histopathology, in particular if bleeding and hydrocephalus are present.

Adult↗
PubMed2006

Spinal intramedullary metastasis of medulloblastoma at initial diagnosis.

CASE REPORT: Spinal magnetic resonance imaging of a 4-year-old boy with medulloblastoma at the initial presentation showed intramedullary lesion without enhancement effect and slight cord swelling from C-5 to T-1. After complete response to the initial therapy, this lesion recurred and slowly expanded. Cervical 11C-methionine-positron emission tomography could establish the diagnosis of intramedullary metastasis. CONCLUSION: Spinal intramedullary metastasis of medulloblastoma at initial diagnosis is extremely rare, but must be considered.

Antineoplastic Agents↗
PubMed2006

Surgical treatment of paraventricular cavernous angioma: fibre tracking for visualizing the corticospinal tract and determining surgical approach.

Surgical treatment of deep-seated lesions involving the corticospinal tract is one of the most challenging areas of contemporary neurosurgery, even given the recent development of radiological methods including three-dimensional anisotropy contrast magnetic resonance imaging (MRI) axonography. Fibre tracking using diffusion tensor imaging is another MRI technique that can be used to visualize anisotropy and the orientation of white matter tracts in the brain. We report herein a patient with a paraventricular cavernous angioma manifesting as hemiparesis caused by haemorrhage. Preoperative conventional MRI failed to determine the anatomical relationship between the paraventricular lesion and the corticospinal tract, whereas fibre tracking using free software (dTV for MR-DTI analysis) indicated that the corticospinal tract was displaced anterolaterally from the medial side. The paraventricular lesion was completely removed without damaging the corticospinal tract using a transcortical transventricular approach. Preoperative fibre tracking is useful in surgical planning for procedures involving deep-seated lesions adjacent to the corticospinal tract, and may avoid postoperative morbidity due to corticospinal tract injury.

Adult↗
PubMed2006

Safety and efficacy of convection-enhanced delivery of ACNU, a hydrophilic nitrosourea, in intracranial brain tumor models.

Convection-enhanced delivery (CED) is a local infusion technique, which delivers chemotherapeutic agents directly to the central nervous system, circumventing the blood-brain barrier and reducing systemic side effects. CED distribution is significantly increased if the infusate is hydrophilic. This study evaluated the safety and efficacy of CED of nimustine hydrochloride: 3-[(4-amino-2-methyl-5-pyrimidinyl) methyl]-1-(2-chloroethyl)-1-nitrosourea hydrochloride (ACNU), a hydrophilic nitrosourea, in rat 9 L: brain tumor models. The local neurotoxicity of ACNU delivered via CED was examined in normal rat brains, and the maximum tolerated dose (MTD) was estimated at 0.02 mg/rat. CED of ACNU at the MTD produced significantly longer survival time than systemic administration (P < 0.05, log-rank test). Long-term survival (80 days) and eradication of the tumor occurred only in the CED-treated rats. The tissue concentration of ACNU was measured by high-performance liquid chromatography, which revealed that CED of ACNU at the dose of 100-fold less total drug than intravenous injection carried almost equivalent concentrations of ACNU into rat brain tissue. CED of hydrophilic ACNU is a promising strategy for treating brain tumors.

Animals↗
PubMed2006

De novo and salvage pathways of DNA synthesis in primary cultured neurall stem cells.

We studied the de novo and salvage pathways of DNA synthesis in sphere-forming neural stem cells obtained from mouse embryos by a neurosphere method. The former pathway needs folic acid (FA) for nucleotide biosynthesis, while the latter requires deoxyribonucleosides (dNS). We examined the proliferative activity of sphere-forming cells in E14.5 embryos by counting the number of spheres formed in media that lacked FA and/or dNS. Proliferation failure and apoptosis occurred in a deficient medium lacking of both FA and dNS. Spheres formed in the deficient medium supplemented with dNS, without FA, did not produce neuron, but rather only seem to generate astrocytes and oligodendrocytes when plated under differentiation condition in culture. On the other hand, a subpopulation of cultured cells formed spheres in the deficient medium supplemented with FA alone in an appropriate concentration, and did possess the self-renewing and multipotential characteristics of neural stem cells. Spheres formed in the media containing low dose Azathioprine and methotrexate, inhibitors of de novo DNA synthesis, were selectively prevented from producing neurons even in the presence of FA. These results suggested that activating de novo DNA synthesis was needed for neural stem cells to proliferate with multipotentiality.

Age Factors↗
PubMed2006

Evaluation of interhemispheric time difference by magnetoencephalography before and after total callosotomy. Two case reports.

Interhemispheric time difference (ITD) measured by electroencephalography (EEG) and magnetoencephalography (MEG) was compared to seizure outcome after callosotomy. Two patients with frequent drop attacks underwent simultaneous EEG and MEG before and after total callosotomy. ITDs in 30 bilateral synchronized (BS) discharges were calculated independently by EEG and MEG. As minimum transcallosal conduction time was suggested to be approximately 20 msec, BS discharges were classified into five categories according to ITD and side: left- or right-leading long (300 to 80 msec), left- or right-leading moderate (80 to 20 msec), and negligible (<20 msec). In Case 1 before callosotomy, EEG detected 77% negligible and 23% right-leading moderate BS discharges, whereas MEG detected 30% and 63%, respectively. After callosotomy, drop attacks reduced remarkably and EEG and MEG detected no BS discharges. In Case 2 before callosotomy, EEG detected 77% negligible and 23% moderate BS discharges, whereas MEG detected 80% and 20%, respectively. After callosotomy, drop attacks recurred 2 months later and EEG and MEG detected left- and right-leading long BS discharges (63% by EEG and 56% by MEG). MEG detected a large number of BS discharges with moderate ITD before surgery in Case 1, suggesting that the transcallosal pathway was the main pathway for the synchronization, whereas the negligible ITD in Case 2 excludes transcallosal propagation. BS discharges with longer ITD after surgery in Case 2 suggest a persistent poly-synaptic non-transcallosal pathway. MEG with higher spatial resolution than EEG may provide surgical indications for callosotomy.

Adolescent↗
PubMed2006

Penetrating atheroma in cervical carotid artery stenosis.

A 61-year-old male presented with left hand motor weakness associated with cerebral infarction in the right frontal lobe. Right common carotid angiography demonstrated a 66% stenosis and carotid duplex scan demonstrated intermediate echogenic plaque, indicating typical carotid plaque. Carotid endarterectomy was performed 22 weeks after the ischemic onset. During exposure of the carotid artery, a soft and yellowish mass (5 x 5 mm) was observed in the lateral wall of the carotid bulbus, which was not covered with adventitia but with thin connective tissue. The mass was removed en-bloc with a small part of the surrounding arterial wall combined with ordinary endarterectomy. The artery was closed with a collagen-impregnated polyester patch graft (Hemashield patch) to maintain adequate arterial lumen. Histological examination of the removed plaque confirmed that atheroma had protruded from the intima through the media as well as the adventitia and formed an extra-arterial mass. Such a case requires great care to dissect the carotid artery to prevent premature disintegration of the atheroma.

Atherosclerosis↗
PubMed2006

Congestive myelopathy due to cervical perimedullary arteriovenous fistula evaluated by apparent diffusion coefficient values - case report.

A 22-year-old woman presented with a cervical perimedullary arteriovenous fistula (AVF) manifesting as right upper and lower extremity weakness. T2-weighted magnetic resonance (MR) imaging showed intramedullary hyperintensity believed to be caused by venous congestion. Preoperative diffusion-weighted MR imaging showed increased apparent diffusion coefficient (ADC) value. Spinal angiography demonstrated an AVF fed mainly by the right C-5 radicular artery. Complete obliteration of AVF was achieved by endovascular embolization and microsurgical shunt occlusion. The ADC value was normalized and her neurological deficits improved after endovascular surgery, whereas T2-weighted MR imaging still demonstrated the lesion. The high preoperative ADC value probably indicated reversible vasogenic edema and immediate normalization of the ADC value suggests a good clinical outcome.

Adult↗
PubMed2006

[Choroid plexus tumors: report of 7 cases in a single institution].

The management of seven patients with choroid plexus tumors, 4 adults and 3 children (mean age 17.5 years) at our institution was reviewed. There were 4 cases of papilloma and 3 of carcinoma located in the lateral ventricle in 1 case, the third ventricle in 1 case, and the fourth ventricle in 5 cases. Total surgical excision was attempted in all patients. Total resection was achieved in three patients, resulting in no deficit in two and persistence of preoperative dysphagia in one. There was no recurrence after total resection. Subtotal resection was achieved in four patients, one of whom underwent second surgery resulting in total resection, and one patient died of respiratory disturbance after the third operation because of regrowth of the tumor. Complete excision could not be achieved in 3 of the 5 tumors located in the fourth ventricle because of extension to the brainstem. The median survival was 59.5 months for patients with papilloma, and 67.7 months for those with carcinoma. Adjuvant therapy was also required for carcinoma, one patient was treated by radiotherapy, and two by radiotherapy plus chemotherapy. Only one patient with papilloma was treated by radiotherapy plus chemotherapy postoperatively.

Adult↗
PubMed2006

[Precocious puberty caused by hCG-producing germinoma involving the bilateral basal ganglia and cerebral white matter without 1ypical radiologic findings: case report].

An 8-year-old boy presented with a rare case of germinoma involving the bilateral basal ganglia and cerebral white matter manifesting as precocious puberty. Magnetic resonance (MR) imaging at the initial presentation demonstrated mild hyperintense areas in the bilateral basal ganglia and corpus callosum on T1-weighted images, and a small hyperintense spot in the right internal capsule on T2-weighted images. Human chorionic gonadotropin (hCG) level was elevated in the cerebrospinal fluid (CSF), so we strongly suspected that threre was a hCG-producing germinoma originating in the bilateral basal ganglia. Stereotactic biopsy was performed. Histological examination revealed two-cell pattern germinoma. After three cycles of combination chemotherapy consisting of ifosfamide, cisplatin, and etoposide, followed by whole brain irradiation with a total dose of 24 Gy, the CSF hCG level fell below the detection limit, but MR imaging demonstrated no significant change. Intracranial hCG-producing germinoma should be suspected in patients presenting with precocious puberty and elevated CSF hCG level. Moreover, slight intensity change on MR imaging is important to identify germinoma arising from the basal ganglia in the early stage.

Basal Ganglia Diseases↗
PubMed2006

[Usefulness of regional cerebral oxygen saturation monitoring in balloon test occlusion].

PURPOSE: Recently, temporary balloon test occlusion (BTO) of the internal carotid artery (IC) has become a well accepted procedure for preoperative evaluation of patients with IC large aneurysms. However, it might be dangerous to move patients fitted with a balloon catheter to the room for single-photon emission computed tomography (SPECT). We attempted to clarify the usefulness of regional cerebral oxygen saturation (rSO2) monitoring during BTO, comparing cerebral blood flow (CBF) obtained from SPECT. MATERIALS AND METHODS: Eight patients with an IC large aneurysm underwent BTO with rSO2 monitoring. Regions of interest in the SPECT were defined in the area below the rSO2 sensor of each hemisphere. Correlations among rSO2, CBF, stump pressure and appearance of symptoms were discussed. RESULTS: The rSO2 significantly reduced during BTO (74.1 +/- 1.2 to 60.4 +/- 2.7%, p < 0.001). The individual decreases in rSO2 correlated with decreases of CBF from SPECT (r = 0.966, P < 0.001). Four patients with deltarSO2 (baseline rSO2 - rSO2 during IC occlusion) less than 12 points had no symptoms, but 4 patients with deltarSO2 more than 14 points had some symptoms. The stump pressure had no correlation with CBF and rSO2. CONCLUSIONS: The rSO2 significantly correlated with CBF from SPECT and related with appearance of symptoms. Our results revealed that rSO2 monitoring was useful in BTO, and SPECT could be skipped in some cases to determine the strategies for treatment of IC large aneurysms.

Adult↗
PubMed2006

[Diagnostic value of perfusion-weighted MRI for evaluating postoperative alteration of cerebral hemodynamics following STA-MCA anastomosis in patients with moyamoya disease].

OBJECTIVE: Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). But little is known about the changes of CBF and its effect on neurological status during the acute stage after direct bypass for moyamoya disease. METHODS AND RESULTS: Perfusion-weighted magnetic resonance imaging (PWI) by the SE-EPI method was performed 4 and 10 days after superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis on 11 sides of 9 patients (male:female = 2:7, 24-61 years old) with moyamoya disease. All patients underwent single-photon emission computed tomography (SPECT) 1 and 7 days after surgery. The time-to-peak (TTP) by PWI showed focal decrease at the site of the anastomosis 4 days after STA-MCA anastomosis compared to preoperative TTP, and was further decreased in larger territory 10 days after surgery in all patients. Postoperative cerebral blood volume (CBV) by PWI showed significant increase compared to preoperative CBV in four patients who suffered symptomatic cerebral hyperperfusion after surgery. Postoperative SPECT revealed apparent increase of CBF in all patients and the patency of the STA-MCA bypass was confirmed by MRA. All patients were discharged without neurological deterioration compared to preoperative neurological status, and none of them suffered ischemic attack after surgery. CONCLUSION: Postoperative decrease in TTP by PWI could be a sensitive parameter for the normalization of CBF after STA-MCA anastomosis in patients with moyamoya disease. Postoperative increase in CBV may suggest cerebral hyperperfusion and could be the optimal predictor for hyperperfusion syndrome after STA-MCA anastomosis in patients with moyamoya disease.

Adult↗
PubMed2006

[Intraoperative brain surface blood flow monitoring using IRIS V thermographic imaging system in patients with Moyamoya disease].

Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving CBF. But little is known about the changes of intraoperative cerebral hemodynamics and its effect on postoperative neurological status including symptomatic cerebral hyperperfusion. To address this issue, we applied a novel infrared camera system (IRIS-V thermographic system) for real-time, visual monitoring of surface CBF during surgery in patients with moyamoya disease. Seven patients (8 sides, male:female= 3:4, 7-62 years old) with moyamoya disease were included in the study. After STA-MCA anastomosis, STA were occluded transiently and recanalized, and whole sequence was recorded by IRIS-V system. Correlation between clinical, radiological findings and infrared imaging were investigated. Patency of bypass was confirmed by this camera during surgery in all cases. The intraoperative imaging patterns were divided into two groups. Group A: Change of brain surface color (++) (3 cases). Group B: Change of brain surface color (-) (4 cases). Transient symptomatic hyperperfusion occurred in all patients in Group A, whereas all patients in Group B showed non-symptomatic transient focal hyperperfusion on SPECT. No patient suffered permanent neurological deterioration compared to preoperative status. Characteristic pattern of the intraoperative cerebral hemodynamics as delineated by IRIS-V could be the optimal predictor for postoperative transient symptomatic hyperperfusion after direct bypass in patients with moyamoya disease.

Adult↗
PubMed2006

["Disease targeting therapy" for neurosurgical disorders: molecular targeting and drug delivery].

Recent progress in molecular biology introduced a concept of molecular targeting therapy against many diseases including neurosurgical disorders. Molecular targeting therapy is promising, because targeting a disease-specific molecule it may provide cure without inducing unfavorable side effects. Focusing mainly on CNS (central nervous system) malignancies, authors discuss the current development of molecular targeting therapy with a special concern to strategies using DNA, RNA, immunotoxin, and molecular selective inhibitors. Strategies using DNA include gene therapy and DNA vaccine. RNA interference (RNAi) is one of the promising molecular targeting strategies using RNA. Immunotoxins such as recombinant chimeric cytotoxin consisting of interleukin-13 and a truncated exotoxin produced by the Pseudomonas aeruginosa bacterium is now under clinical investigation. Many molecular targeted agents such as selective inhibitors for protein kinases are now in preclinical and clinical development for patients with malignant glioma. Additionally, authors introduce their attempts to visualize the local drug delivery using real-time MRI monitoring. Visualization of drug delivery, while achieving effective drug distribution using convection-enhanced delivery (CED), may also contribute to the disease targeting. These strategies together should help us develop the effective 'disease-targeting therapy' for CNS disorders.

Biotechnology↗
PubMed2005

The relationship among p53 oligomer formation, structure and transcriptional activity using a comprehensive missense mutation library.

Tumor suppressor p53 forms a homo-tetramer through its COOH-terminal oligomerization domain and acts as a sequence-specific transcription factor. We have analysed the interrelation among the transcriptional activities, the structure and the cancer-related mutations in the oligomerization domain by using a comprehensive missense mutation library. Here, we examined the ability of 184 mutant p53s in the domain to form an oligomer by expressing these mutant p53s in yeast, and compared the data with the previous information. We showed that specific residues in the alpha-helix and the beta-strand of the oligomerization domain were critical for both oligomer formation and sequence-specific transactivation, and the activities were closely related. In particular, the alpha-helix was more sensitive to amino-acid substitutions than the beta-strand. We found identity in the interrelation between the two activities, that is, monomer mutants were transcriptionally inactive whereas dimer and tetramer mutants retained their transcriptional activities. In TP53 mutation databases, a small number of mutations have been reported in this domain. Surprisingly, most do not encode p53s defective in functional properties. These results indicate that, although oligomer formation is essential for p53 transactivation function, the inactivation of oligomer formation and therefore the inactivation of transactivation may not be essential for tumor suppression by p53 because they do not lead to oncogenic proteins.

Biopolymers↗
PubMed2005

Fronto-basal interhemispheric approach for craniopharyngiomas extending outside the suprasellar cistern.

OBJECTIVE: The aim of the present study was to establish the usefulness of the fronto-basal approach with a relatively small craniotomy window for the removal of tumors protruding from the sellar-suprasellar region to the third and basal cistern. METHOD: Forty-two patients who were surgically treated for craniopharyngiomas extending outside the sellar-suprasellar region were evaluated. All the patients were operated on by the fronto-basal interhemispheric approach, and the average follow-up period was 5 years. RESULTS: Gross total resection of the lesion was achieved in 30 cases. Eight patients underwent subtotal resection and four patients underwent partial removal due to recurrence after previous surgeries with or without radiotherapy. In the immediate postoperative period, major complications, including impairment of the cranial nerves, were observed in two cases. One patient exhibited transient memory disturbance due to infarction of the perforator; after 3 months, this symptom was ameliorated. Three of the patients died during follow-up; however, 6 of the 30 undergoing gross total removal and 10 of the 12 patients undergoing subtotal or partial removal suffered regrowth. Ultimately, a total of 12 patients underwent re-operation with the same approach or combined with the orbito-zygomatic approach. CONCLUSION: In our experience, the fronto-basal interhemispheric approach, even through a small craniotomy window, is a valid choice for the removal of craniopharyngiomas extending outside the sellar-suprasellar region. Using this approach, tumors can be removed without significant sequelae related to surgical technique due to easy preservation of the pituitary stalk, hypothalamic structures, and perforators. This approach offers a safe and minimally invasive means of treating craniopharyngiomas.

Adult↗
PubMed2005

Neuromagnetic evaluation of binaural unmasking.

Binaural unmasking refers to the improvement in intelligibility under conditions of masking when a tone is presented out of phase rather than in phase. In the present study, binaural unmasking was evaluated using auditory-evoked magnetoencephalography (MEG) in eight healthy right-handed volunteers (7 males and 1 female, mean age 25.9 years). Peak latency and amplitude of the N1m response to tone bursts of 250 Hz (n = 8), 1000 Hz (n = 3), and 4000 Hz (n = 3) were measured under S0N0 (binaural phase difference was zero radian (in phase) for both stimulus sound and masker noise) and SpiN0 (binaural phase difference was pi radian (out of phase) for stimulus sound and zero radian for masker noise) conditions. The level of tone bursts was swept by 5 or 10 dB steps from the level of 20 dB above the psychophysical threshold under the S0N0 condition until no significant auditory-evoked field could be observed. Identical background noise was presented to both ears continuously at 50 dB SPL. N1m responses to stimuli at or above the psychophysical threshold were found bilaterally in all subjects except one who had only right hemispheric N1m. N1m response for the SpiN0 stimulus had larger amplitude and shorter latency than that for the S0N0 stimulus in each hemisphere and at each sound level. Neuromagnetic binaural unmasking was greatest around the threshold level, corresponding to psychophysical binaural unmasking; became smaller with greater stimuli, indicating the suprathreshold unmasking effect; and disappeared at around 15-20 dB above the threshold. Psychophysical binaural unmasking can be quantitatively evaluated by MEG in the auditory cortex level of the bilateral hemispheres.

Adult↗