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Tatsuya Tanaka

Publications and source records attributed to Tatsuya Tanaka.

18 recordsLinked to original sources
PubMed2006

Focal cortical dysplasia: pathophysiological approach.

OVERVIEW: Clinical and experimental studies on focal cortical dysplasia (FCD) were carried out. MATERIALS AND METHODS: For the experimental study, an experimental FCD model of rats was developed. Twenty Wistar rats at 0-2 days after birth were used for the study. Kainic acid (KA) solution was injected stereotaxically into medial and lateral sites of the sensori-motor cortex. Bipolar electrodes were inserted in five rats. Their behavior and electroencephalogram (EEG) were recorded using a digital-video-EEG monitoring system. After observation periods of 1, 2, and 6 months, rats were perfused for pathological study. FCD was observed adjacent to the site of KA injection in all rats more than 1 month after the injection. RESULTS AND DISCUSSIONS: EEG recording demonstrated focal spike discharges in and around the site of injection. However, clinical seizure was not observed. Pathological studies showed decrease in GABA-A receptors and increase in GABA-B receptors not only in the lesion but also in perilesional areas. Fifteen surgical cases of FCD with intractable epilepsy were subjected to the clinical study. Neuro-imaging studies including high-resolution magnetic resonance imaging and single-photon emission computed tomography were performed. Conventional EEG studies demonstrated focal EEG abnormalities with epileptic phenomena. At surgery, intraoperative electrocorticography (ECoG) was performed to localize epileptic foci under neuroleptoanalgesia. Thirteen patients showed epileptiform discharges on preresection ECoG. All foci in non-eloquent areas were resected. Pathological studies including immunohistochemical staining were performed, and the characteristics of the FCD in relation to EEG findings were analyzed. Patients in whom total lesionectomy with complete focus resection was performed had favorable postoperative courses. Nine patients (64.3%) have been seizure-free with reduced medication, and significant improvement was achieved in two patients (14.3%). Electrophysiological examination revealed epileptogenecity not only in the lesions but also in perilesional areas. The immunohistochemical studies showed a decrease in GABA-A receptors and an increase in GABA-B receptors in both the lesions and perilesional areas, but N-methyl-D: -aspartate receptors were almost negative in both areas. Glutamate R1 was decreased in both areas, but glutamate R2 was increased in both areas. These findings support the results of a electrophysiological study. CONCLUSIONS: In conclusion, not only the epileptic property of experimental focal cortical dysplasia but also perilesional epileptogenesis was demonstrated. These findings supported the results of surgery for patients with focal cortical dysplasia. In cases of FCD, total removal of the lesion and resection of the perilesional epileptic focus are needed for a good outcome.

Adolescent↗
PubMed2006

[A case of coexistence with cavernous angioma and focal cortical dysplasia].

There have recently been a number of new pathological findings of specimens from epileptic foci that have become widespread of surgical treatment. We reported a case with seizures resulting from brain lesions which pathologically demonstrated a coexistence with a cavernous angioma and a focal cortical dysplasia. A 24-year-old man was admitted to our hospital because of generalized convulsion from 1 year ago. Brain MRI revealed an enhanced mass lesion, in diameter 1.5 cm, with hemosiderin rim in the left temporal tip. Ictal EEG showed the initiation of the spike from the lateral side of the left temporal lobe. Because the epileptogenic focus was thought to be the lateral side in the left temporal lobe, anterolateral temporal resection was performed and subsequently total removal of the tumor was performed. He had no seizure after surgery. A light microscopic examination was performed on specimens stained with hematoxilin and eosin. We verified to be pathologically coexistent with a cavernous angioma and a focal cortical dysplasia. We also found unusual neurons that were accompanied by perineuronal glial satellitosis in the subcortical white matter, those were occasionally observed in epileptic foci and were thought to be a form of neuronal migration disorders.

Adult↗
PubMed2005

Application of wavelet transform in pulsed ultrasonic modulation voltammetry.

In this study, wavelet transform was employed to achieve the different current components in pulsed ultrasonic modulation voltammetry. It was found that the pulsed sonovoltammograms could be decomposed into wavelet approximations and wavelet details by projecting wavelet transform on the signals in question. Since wavelet approximations with a certain scale parameter may retain the waveform of the original signal, the current components resulted from ultrasound "on" and "off" in pulsed sonovoltammograms could be separated at a certain scale parameter in multiplying wavelet approximation. With this method, the current components corresponding to pulse-on and pulse-off can be recorded separately without the external data acquisition system used in general modulation voltammetric measurements. The current difference between the two states was found to be proportional to the concentration of the electro-active species. The analytical usefulness of this approach was exploited for determination of ferrocyanide ion at sub-micromolar concentrations.

Journal Article↗
PubMed2005

A novel missense mutation in a Japanese patient with gelatinous droplike corneal dystrophy.

PURPOSE: To report a novel missense mutation in TACSTD2 gene, L186P, responsible for gelatinous droplike dystrophy (GDLD). DESIGN: Case report and experimental study. METHOD: A 10-year-old Japanese boy suffering from typical GDLD was studied. A 1.1-kb DNA fragment of the TACSTD2 gene was amplified and analyzed using a molecular biological method. cDNA from the patient's cornea was also analyzed to determine which allele was expressed in the patient's corneal epithelium. RESULTS: Sequence analysis revealed that the patient is a compound heterozygote for the Q118X mutation and the L186P, the first missense mutation found in Japanese GDLD. Polymerase chain reaction-restriction fragment length polymorphism analysis from cDNA of patient's cornea revealed that the L186P missense mutation allele is expressed in the patient's corneal epithelium. CONCLUSION: We describe a novel mutation in one case of Japanese GDLD. The results confirm that the missense mutation L186P in the TACSTD2 gene is also responsible for the GDLD phenotype.

Antigens, Neoplasm↗
PubMed2005

Clinical application of experimental cortical dysplasia in rats.

This report details clinical and experimental studies of focal cortical dysplasia. The first part deals with 14 surgical cases of children with intractable epilepsy. At surgery, intraoperative electrocorticography was performed to localize the epileptic foci under neuroleptanalgesia. Thirteen patients showed epileptiform discharges on this preresection electrocorticography. All foci in noneloquent areas were resected. Patients who had undergone total lesionectomy with complete focus resection showed the most favorable postoperative results. However, the positive correlation between the intraoperative electrocorticographic findings and the pathologic classification of cortical dysplasia was not found in the present study. Nine patients have been seizure free with reduced medication and two patients have achieved worthwhile improvement. We conclude that intraoperative electrocorticography can improve the surgical outcome for intractable epilepsy by localizing epileptic foci for resection. The second part describes a kainic acid-induced experimental model of focal cortical dysplasia, which demonstrated not only the epileptic properties of the dysplasia but also the perilesional epileptogenicity. The findings supported the surgical results for the patients with focal cortical dysplasia.

Adolescent↗
PubMed2004

Correct localization of epileptogenic focus with I-123 iomazenil cerebral benzodiazepine receptor imaging: a case report of temporal lobe epilepsy with discordant ictal cerebral blood flow SPECT.

A 26-year-old female with intractable epileptic seizures was studied with I-123 iomazenil cerebral benzodiazepine receptor, I-123 IMP inter-ictal and Tc-99m ECD ictal cerebral blood flow SPECT. The ictal cerebral blood flow SPECT indicated the location of the seizures to be in the left temporal lobe, where increased regional cerebral blood flow was noted in marked contrast to the inter-ictal SPECT. Ictal electroencephalograms (EEGs) recorded with scalp and sphenoidal electrodes also suggested the left temporal lobe as the location of the seizures. On I-123 iomazenil SPECT, however, decreased benzodiazepine receptor density was demonstrated in the right temporal lobe. MRI showed mild atrophy and abnormal signal intensity in the right temporal lobe. Ictal EEGs recorded with intracranial electrodes revealed that abnormal electrical activity of the brain always emerged from the right temporal lobe and then propagated to the contralateral side. Based on the findings of intracranial EEGs, partial resection of the right anterior temporal lobe including hippocampus was performed. After the surgery, no seizure occurred. Pathological examination of the surgical specimens revealed hippocampal sclerosis. This case suggested that cerebral benzodiazepine receptor imaging with I-123 iomazenil can be helpful for correct localization of epileptogenic foci.

Adult↗
PubMed2004

Clinical and experimental studies of epilepsy associated with focal cortical dysplasia.

The results of clinical and experimental studies on epilepsy associated with focal cortical dysplasia (FCD) are presented. We have been interested in the findings of abnormal increases in the numbers of small vessels in specimens of FCD resected from epilepsy patients. In the clinical study of 13 patients with epilepsy, specimens of FCD or dysembryoplastic neuroepithelial tumor (DNT) were examined using immunohistochemistry. The number of vessels in both lesions were greater than those in cortical specimens of autopsy cases without epilepsy. Because the vessels showed negative staining of VEGF, it was thought that the phenomenon of increase in the number of vessels was simply a hypervascularity, not a neovascularity. The local hypervascularity was expected to show local hyperperfusion in CBF-SPECT study, but interictal SPECT demonstrated local hypoperfusion and ictal SPECT showed hyperperfusion. This may have been caused by a functional change in those vessels. In the experimental study, we tried to make a new animal model of FCD to study epileptogenicity of FCD. When kainic acid had been infused into the neocortex in the neonatal rats, FCD was induced in adult Wistar rats. Histopathological examination revealed cortical dyslamination and abnormal neurons. On EEG, local spike bursts were elicited from the lesions, however, clinical seizures were not detected. Although the data are preliminary and observation over a longer period is required to determine whether spontaneous seizures will occur in this model, it is expected that this new model will be useful for studying epilepsy associated with FCD.

Animals↗
PubMed2004

Evaluation of the response of metastatic brain tumors to stereotactic radiosurgery by proton magnetic resonance spectroscopy, 201TlCl single-photon emission computerized tomography, and gadolinium-enhanced magnetic resonance imaging.

OBJECT: The goal of this study was to investigate the usefulness of proton (1H) magnetic resonance (MR) spectroscopy to evaluate the response of metastatic brain tumors to stereotactic radiosurgery (SRS) in comparison with Gd-enhanced MR imaging and single-photon emission computerized tomography with administration of thallium-201 chloride (201TlCl-SPECT). METHODS: Forty patients with a total of 47 metastatic brain tumors were evaluated. The primary lesion was identified in all cases. Stereotactic radiosurgery was effective in 37 lesions. All patients were examined using Gd-enhanced MR imaging before and after SRS. Thalium-201 chloride was administered to 27 patients with 34 tumors and SPECT images were obtained. Proton MR spectroscopy was performed in 36 patients who harbored 43 tumors. On Gd-enhanced MR images, a decrease in the volume of the Gd-enhanced lesion and a change in the enhanced effect in the lesion after treatment were recognized as showing the effectiveness of SRS between 1 and 3 months or more (mean 8.54 +/- 3.58 weeks). In 201TlCl-SPECT studies, the ratio of lesion to normal brain decreased from 2 weeks to 2 months (mean 5.03 +/- 2.77 weeks) after radiosurgery. On 1H-MR spectroscopy images a high choline (Cho) peak and a lipid-dominant (Lip) peak were observed in 25 lesions and a high Cho peak and a lactate-dominant (Lac) peak were observed in 12 lesions before SRS. A decrease in the Cho peak, a disappearance of the Lac peak, and an increase in the Lip peak were observed between 1 week and 1 month (mean 2.76 +/- 1.62 weeks) after treatment. CONCLUSIONS: Based on histopathological findings obtained at autopsy or at surgery, we assume that a high Cho peak may be observed in viable tumor tissue and a Lip peak in areas of necrosis. The results indicate that 1H-MR spectroscopy is potentially a more sensitive tool in evaluating the response to SRS than 201TlCl-SPECT or Gd-enhanced MR imaging and that it can be used earlier for this purpose than those other imaging methods.

Adult↗
PubMed2004

[Three-dimensional neuroimaging in diagnosis and surgical treatment for epilepsy].

Development of functional neuroimaging is contributed to diagnosis and treatment in epilepsy patients. The dipole analysis of interictal spikes on EEG or MEG provides 3D-localization of the irritable zone. Interictal and ictal CBF-SPECT reveals the local change in CBF associated to epileptic focus. Three-dimensional stereotactic surface projection (3D-SSP) of SPECT is useful to recognize the seizure generation area. Furthermore, Subtraction ictal SPECT coregistration of MRI (SISCOM), that is fusion image of anatomical and functional brain images, is beneficial to understand the localization of seizure-induced hyperperfusion area. During epilepsy surgery, image-guided system makes less-invasive and accurate surgery possible. Functional image-guided surgery for epilepsy will be available in near future.

Adult↗
PubMed2003

Eradication and reinfection of human papillomavirus after photodynamic therapy for cervical intraepithelial neoplasia.

BACKGROUND: Photodynamic therapy (PDT) has been proven to be a promising therapeutic modality for selected dysplasias and malignancies in a variety of organs. We assessed the effectiveness of PDT for treating cervical intraepithelial neoplasia (CIN) by cytological and histological examinations and investigated its impact on human papillomavirus (HPV) infection. METHODS: A series of 31 patients with CIN (2 with CIN2, 29 with CIN3) were given polyhematoporphyrin ether/ester (PHE) 2 mg/kg IV. After 60 h their cervices were exposed to a 630-nm YAG-OPO laser. HPV-DNA extracted from cervical smears was amplified by the polymerase chain reaction and typed for HPV using restriction fragment length polymorphism. RESULTS: At 3 months after PDT, cytology and directed biopsy of the cervix revealed regression of the disease in 28 [complete remission (CR) rate 90%] of 31 patients, and HPV-DNA could be no longer detected in the cervical smears of 22 (76%) of 29 HPV-positive patients. After 12 months, all 31 patients had achieved a CR on biopsy, although HPV-DNA was still present in the cervical smears of 6 patients. The types of HPV-DNA detected 12 months after PDT were different from those seen before PDT in each of the 6 patients, suggesting that they might be reinfected with other HPV types after PDT. CONCLUSION: PDT is effective not only in improving the cytological and histological measures when treating CIN but also for eradicating cervical HPV.

Adult↗
PubMed2002

Loss of Igf2 imprinting in monoclonal mouse hepatic tumor cells is not associated with abnormal methylation patterns for the H19, Igf2, and Kvlqt1 differentially methylated regions.

IGFII, the peptide encoded by the Igf2 gene, is a broad spectrum mitogen with important roles in prenatal growth as well as cancer progression. Igf2 is transcribed from the paternally inherited allele, whereas the linked H19 is transcribed from the maternal allele. Igf2 imprinting is thought to be maintained by differentially methylated regions (DMRs) located at multiple sites such as upstream of H19 and Igf2 and within Kvlqt1 loci. Biallelic expression (loss of imprinting (LOI)) of Igf2 is frequently observed in cancers, and a subset of Wilms' and intestinal tumors have been shown to exhibit abnormal methylation at H19DMR associated with loss of maternal H19 expression, but it is not known whether such changes are common in other neoplasms. Because cancers consist of diverse cell populations with and without Igf2 LOI, we established four independent monoclonal cell lines with Igf2 LOI from mouse hepatic tumors. We here demonstrate retention of normal differential methylation at H19, Igf2, or Kvlqt1 DMR by all of the cell lines. Furthermore, H19 was found to be expressed exclusively from the maternal allele, and levels of CTCF, a multifunctional nuclear factor that has an important role in the Igf2 imprinting, were comparable with those in normal hepatic tissues with no mutational changes detected. These data indicate that Igf2 LOI in tumor cells is not necessarily linked to abnormal methylation at H19, Igf2, or Kvlqt1 loci.

Animals↗
PubMed2002

Complex partial status epilepticus induced by a microinjection of kainic acid into unilateral amygdala in dogs and its brain damage.

OBJECTIVE: In order to investigate kainic acid (KA)-induced amygdaloid seizure and seizure-induced brain damage in dogs, and to compare these findings with that in other species, a KA-induced seizure model in dogs was produced. MATERIAL AND METHODS: Normal beagle dogs were used. A Teflon cannula for KA injection was inserted into the left amygdala, and cortical or depth electrodes were positioned. One week after surgery, 1.5 microg of KA was microinjected into the left amygdala. EEGs and the behavior of the animals were monitored for 2 months after KA injection. In addition, neuron-specific enolase levels in the cerebrospinal fluid (CSF-NSE) were measured intermittently. At 2 months after the injection, histopathological studies were performed. RESULTS: KA-treated dogs showed limbic seizures that started from the left amygdala within 30 min after injection. The seizures developed into complex partial status epilepticus (CPSE), and started independently from the bilateral amygdala during the CPSE. The CPSE lasted for 1-3 days, and the animals showed no spontaneous seizures during the 2-month observation period. A significant increase in CSF-NSE was observed immediately after CPSE. Histopathologically, extensive necrosis, which formed large cavity lesions, was observed around the bilateral amygdala. SUMMARY: A microinjection of KA into unilateral amygdala in dogs induced CPSE. The seizures elicited independently from bilateral amygdala, and bilateral limbic structures suffered extensive injury. In addition, CSF-NSE was demonstrated as a useful marker of acute neuronal damage.

Amygdala↗
PubMed2002

Electrophysiological, behavioral and metabolical features of globus pallidus seizures induced by a microinjection of kainic acid in rats.

There has been few studies of the globus pallidus in relation to epilepsy. In this study, kainic acid (KA)-induced globus pallidus seizure was electrophysiologically, electroencephalographically, histopathologically and metabolically investigated in rats. Sixteen Wistar rats weighing 250-350 g were used. Under intraperitoneal pentobarbital anesthesia, a stainless-steel cannula was inserted stereotaxically into the left globus pallidus pars externa (GPe) for KA injection. For recording EEG, a depth electrode was inserted into the left GPe, just posterior to the tip of the injection guide cannula. Electrodes were also inserted into the right globus pallidus and bilateral sensorimotor cortex (SMC). EEG changes after KA injection were classified as follows: Continuous low-voltage spikes were observed in the left GPe on EEG at stage 1. Intermittent multiple spikes and wave complexes began to propagate to the left SMC at stage 2. Continuous spikes and wave complexes began to propagate to the bilateral SMC at stage 3. Secondary generalized seizures were observed at stage 4. Globus pallidus seizures recurred every 7-9 min and lasted for 4-6 h. However, the seizures gradually subsided and became normal within 18 h. No spontaneous seizure was detected for the next 30 days. Histopathological study revealed a small gliotic lesion with neuronal cell loss around the cannula tip. Neither degeneration nor neuronal cell loss in the ipsilateral hippocampus were observed. The autoradiogram using [14C]2-deoxyglucose during seizure status demonstrated a remarkable increase of local cerebral glucose utilization not only in the GPe but also in the GPi. An increase glucose metabolism was also found in the follows: the medial and lateral septal nucleus, substantia nigra, hippocampus, frontal cortex, parietal cortex, piriform cortex, entorhinal cortex, accumbens nucleus, ventral and lateral nucleus of the thalamus, amygdala, and ventral nucleus of hypothalamus. KA injection into the unilateral GPe evoked not only epileptic excitation of the cortex but also transient enhancement of the globus pallidus-substantia nigra circuit.

Action Potentials↗
PubMed2002

Effect of mild hypothermia on energy state recovery following transient forebrain ischemia in the gerbil.

A transient (lasting for 15 min) bilateral carotid artery occlusion model was created by using male Mongolian gerbils ( n=20, weight 50-60 g). The animals were divided into a group with mild hypothermia (34 degrees C, n=10) and a normothermic group (37 degrees C, n=10). High-energy phosphate metabolism (ATP, PCr, Pi) and intracellular pH were sequentially measured using (31)P-MRS during ischemia and after reperfusion for 1 week. The same animals were also subjected to a histopathological evaluation. During ischemia, there were no statistically significant differences between the two groups in the quantities of the metabolites. However, after reperfusion the rate of metabolic recovery by the mildly hypothermic (MH) group was significantly higher (by 10-20%) than the normothermic (NT) group. The intracellular pH decreased about 0.4 in both groups after ischemia; and after reperfusion the intracellular pH of the MH group returned to baseline levels faster than in the NT group. One week after ischemia, energy metabolism gradually decreased about 10-20% in both groups. In the histopathological evaluation, pyramidal cell damage in the hippocampus was 33% on average in the MH group and 79% in the NT group. The neuronal damage to the cerebral cortex was 26% in the MH group and 61% in the NT group. Astrocyte reactivity in the hippocampus and cerebral cortex was 2.9% and 1.1% in the MH group and 9.7% and 5.2% in the NT group. The results of this experiment indicate that the protective effect of mild hypothermia is due to the high recovery rate of ATP and PCr and the prevention of a secondary decline in high phosphate energy.

Adenosine Triphosphate↗
PubMed2002

A case of intracranial arteriovenous fistula in an infant with neurofibromatosis type 1.

INTRODUCTION: Reported cases of arteriovenous fistula (AVF) with neurofibromatosis type1 (NF1) are rare. CASE REPORT: In this paper we report the first case of intracranial AVF in an NF1 infant who developed heart failure. Endovascular treatment using coils successfully obliterated the AVF. The mechanism underlying the AVF in this case was believed to be a congenital mesenchymal abnormality of the intracranial vessels. DISCUSSION: The mechanism underlying the development of heart failure in this case is also discussed.

Arteriovenous Fistula↗
PubMed2002

Genomic structure of the rat and mouse histamine N-methyltransferase gene.

Northern blotting analysis revealed different tissue distribution patterns of HMT mRNA between mice and rats. In the mouse, mRNA expression was detected in the brain, kidney and liver. In the rat, there was an extremely high mRNA signal only in the kidney. We isolated and characterized the rat and mouse histamine N-methyltransferase (HMT) genes from genomic DNA libraries. The rat HMT gene consists of 6 exons and 5 introns. The mouse HMT gene structure was similar to that of the rat, but had one additional exon 5' upstream from the exon containing a start codon, resulting in seven exons. Several long interspersed repetitive elements were located in the 5' flanking region of the rat and mouse HMT gene. Despite high sequence conservation of the regions around exon 6 and the 3' flanking region, the 5' flanking region had little similarity between the rat and mouse. Marked sequence similarities between rat and mouse introns were present near splice sites and outside the junction residues, suggesting the evolutionary relationship between the structural features of the rat and mouse HMT genes. This observation may explain the species difference of the tissue expression pattern of HMT mRNA.

Animals↗