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Tomokatsu Hori

Publications and source records attributed to Tomokatsu Hori.

At least 19 recordsLinked to original sources
PubMed2007

[Information guided technology and procedure in neurosurgical field].

Translational Research is the research to apply and mediate a fundamental research result to the clinical field effectively. The integration of the diagnosis and the treatment is an important item in the life science field from the viewpoint of quality of therapy and minimally invasive therapy. The standardization of mechanical interface of the medicine related machine, system and a medical information system are important from the viewpoint such as prevention of medical malpractice. A high function operating robot (manipulator) as an endoscopic robot and image-guided minimally invasive device are important in the point of view of the development of a medical device shown with a medical device industry vision. We describe an outline of our ongoing development of endoscope system, intraoperative MRI (intelligent operating theater) and robot surgery system in neurosurgical field.

Humans↗
PubMed2006

Expression of type 5 somatostatin receptor in TSH-secreting pituitary adenomas: a possible marker for predicting long-term response to octreotide therapy.

In TSH-secreting pituitary adenomas (TSHoma), octreotide (OCT) therapy reduces tumor size and TSH secretion in some cases but not in others. As OCT acts through various types of somatostatin receptors (SSTRs), the different responses of TSHoma to OCT might be explained by the differences of SSTR expression. We therefore studied the expression of subtype-specific SSTR mRNA transcripts in tumor tissues by RT-PCR. Type 2 (SSTR2) mRNA transcripts were detected in all 8 tumors but those of SSTR3 and SSTR5 were demonstrated only in 5 of them. Serum TSH levels were decreased by OCT administration test in all patients but OCT therapy was effective in two patients out of three. SSTR5 mRNA was detected in two tumors from the responder, but not in one tumor that was resistant to OCT. These observations suggest that the temporal decrease of TSH by OCT may be mediated by SSTR2, and that the long term response to OCT therapy may be related with the expression of SSTR5. Therefore, the expression of SSTR5 in TSHoma may be a useful marker for predicting the outcome of the therapy, but further studies with larger numbers of patients are necessary.

Adenoma↗
PubMed2006

The alanine/threonine polymorphism of the alpha-1-antichymotrypsin (SERPINA3) gene and ruptured intracranial aneurysms in the Japanese population.

BACKGROUND: Serine protease inhibitor member 3 of clade A (SERPINA3), also known as alpha-1-antichymotrypsin, inhibits the activity of cathepsin G. The release of neutrophil cathepsin G (proteolytic enzyme) can destroy the vascular matrix through degradation, platelet aggregation and coagulation disorders. In a previous report there was evidence that an alanine/threonine polymorphism was associated with the risk factor for aneurysmal subarachnoid hemorrhage (SAH) in a Polish population. We performed this study to determine whether this A15T polymorphism shows the same association in a Japanese population. METHODS: A total of 437 patients with an aneurysmal SAH and 405 control cases of Japanese origin were genotyped for the A15T polymorphism and 2 further intronic single nucleotide polymorphisms by using polymerase chain reaction and direct sequencing. RESULTS: In the patients with intracranial aneurysms the SERPINA3 A15T allele and genotype distribution did not differ significantly from the controls. CONCLUSION: In the Japanese population the A15T polymorphism of the SERPINA3 gene is not associated with aneurysmal SAH.

Alanine↗
PubMed2006

Clinical and radiological features related to the growth potential of meningioma.

Clinical and radiological features that help predict the growth potential of meningioma would be beneficial. The purpose of this study is to clarify the characteristics related to proliferating potential using the MIB-1 staining index. We analyzed the relationship of MIB-1 staining indices to characteristics of 342 consecutive patients with meningioma surgically removed between 1995 and 2004 by logistic regression analysis. One hundred and forty-nine of the patients with meningioma were >or=60 in age; 89 male; 48 recurrent; 203 symptomatic; 157 at the skull base; 124 over 20 cm(3); 24 multiple; 136 with edema; 117 with calcification. The MIB-1 staining index in 56 of 296 grade I meningiomas in WHO classification was >or= 3.0; in 27 of 28 grade II; and in 17 of 18 grade III, respectively. Logistic regression analysis demonstrated that male (odds ratio [OR], 2.374, p=0.003), recurrence (OR, 7.574, p=0.0001), skull base (OR, 0.540, p=0.035), calcification (OR, 0.498, p=0.019) were independent risk factors for a high MIB-1 staining index (>or=3.0); age, symptomatic, volume, multiple, edema were not. Male, recurrence, non-skull base, absence of calcification are independent risk factors for a high proliferative potential. These should be taken into consideration when managing meningiomas.

Adult↗
PubMed2006

Intrasellar remote metastasis from adenoid cystic carcinoma of parotid gland: case report.

Adenoid cystic carcinoma is a tumor of exocrine glands originating primarily from the minor and major salivary glands, lacrimal gland, bronchus, breast, and intestinal and genital tracts. Intracranial remote metastasis from adenoid cystic carcinoma in salivary gland is quite rare. The authors encountered a case of intrasellar remote metastasis from an adenoid cystic carcinoma of parotid gland origin, presenting with hyponatremia secondary to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). To our knowledge, this is the first reported case of metastasis from an adenoid cystic carcinoma to intrasellar area. A 78-year-old woman had an adenoid cystic carcinoma in the left parotid gland, which was resected surgically followed by local radiation therapy of 60 Gy. After 4 years, the patient presented with general malaise, followed by disturbed consciousness caused by hyponatremia. The clinical data showed severe hyponatremia induced by SIADH. An intrasellar heterogenous mass lesion compressing the optic chiasm was resected subtotally via an endonasal transsphenoidal approach. Histopathological examination of the tumor specimens revealed adenoid cystic carcinoma, which had identical histological findings as those of the painful superficial cervical lymph nodes resected in the same operation. Tumors such as the present case are easily confused with pituitary adenoma or craniopharyngioma. Although rare, metastasis from tumors including those of salivary gland origin should be considered in the differential diagnosis of unusual pituitary tumors.

Aged↗
PubMed2006

Hyponatremia after transsphenoidal surgery for hypothalamo-pituitary tumors.

Transient diabetes insipidus is a well-known complication after transsphenoidal surgery (TSS). On the other hand, transient hyponatremia has been reported as being a delayed complication of TSS. Transient hyponatremia has been attributed to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), but the details of hyponatremia have not been clarified. In the present study, we retrospectively reviewed 110 consecutive patients (39 males and 71 females, age 9-80 years) operated on transsphenoidally for pituitary and hypothalamic tumors. We investigated the frequency, time of onset, duration of hyponatremia after TSS, and analyzed possible factors associated with it. A postoperative sodium concentration <135 mEq/l was observed in 29 (26%) patients. Five patients were excluded from this study because their hyponatremia could be due to either overdose of desmopressin or SIADH for meningitis. Therefore, we investigated 24 (22%) patients with hyponatremia in this study. The sodium levels in the patients with hyponatremia ranged from 110 to 134, with a mean of 126.2 +/- 5.3 mEq/l. Hyponatremia was observed on average on postoperative day 9.5 +/- 2.4, the serum sodium levels normalized within 3.8 +/- 1.7 days. Hyponatremia occurred in patients with non-functioning pituitary adenoma (26%, 11/42), Rathke's cleft cyst (29%, 5/17), prolactinoma (31%, 4/13) and acromegaly (15%, 4/27). 18 patients (75%, 6/24) who developed hyponatremia had macrotumor (>10 mm), and 6 patients (25%, 6/24) had microtumor. The plasma arginine vasopressin (AVP) levels in the patients with hyponatremia ranged from 0.21 to 2.1, with a mean of 0.79 +/- 0.46 pg/ml, and the levels were inversely correlated with plasma osmolality (r = -0.80, p = 0.002). The urine to plasma osmolality ratios were >1. All the patients received appropriate hormonal replacement, including hydrocortisone. These data showed that postoperative hyponatremia after TSS was not rare, and the hyponatremia was mainly associated with SIADH. As the hyponatremia could be a life-threatening complication, all patients should be screened for serum electrolytes after TSS.

Adolescent↗
PubMed2006

[Rathke's cleft cyst].

Explore the source record for details and available documents.

Central Nervous System Cysts↗
PubMed2006

A haplotype spanning two genes, ELN and LIMK1, decreases their transcripts and confers susceptibility to intracranial aneurysms.

The rupture of an intracranial aneurysm (IA) results in subarachnoid hemorrhage, a catastrophic neurological condition with high morbidity and mortality. Following-up on our previous genome-wide linkage study in Japanese population, we extensively analyzed a 4.6 Mb linkage region around D7S2472 on 7q11 by genotyping 168 single nucleotide polymorphisms (SNPs). SNP association and window scan haplotype-based association studies revealed a susceptibility locus for IA on a single LD block covering the 3'-untranslated region (3'-UTR) of ELN and the entire region of LIMK1. An association study with 404 IA patients and 458 non-IA controls revealed that the ELN 3'-UTR G(+659)C SNP has the strongest association to IA (P=0.000002) and constitutes a tag-SNP for an at-risk haplotype, which contains two functional SNPs, the ELN 3'-UTR (+502) A insertion and the LIMK1 promoter C(-187)T SNP. These allelic and haplotype-based associations were confirmed in a Korean population. Ex vivo and in vitro analyses demonstrate that the functional impact of both SNPs is the decrease of transcript levels, either through accelerated ELN mRNA degradation or through decreased LIMK1 promoter activity. Elastin and LIMK1 protein are involved in the same actin depolymerization signaling pathway; therefore, these lines of evidence suggest a combined effect of the SNPs in the at-risk haplotype possibly by weakening the vascular wall and promoting the development of IA.

3' Untranslated Regions↗
PubMed2006

Is there any evidence for linkage on chromosome 17cen in affected Japanese sib-pairs with an intracranial aneurysm?

A linkage region on chromosome 17cen has previously been found in 29 Japanese families with a history of familial intracranial aneurysms (IA). To investigate whether there is evidence of linkage in affected Japanese sib-pairs we performed nonparametric and parametric linkage analysis of a total of 253 familial aneurysm cases including 111 affected sib-pairs (ASP). Ten microsatellite markers covering a 17.7 cM region were chosen, in accordance with previous work in which nominal P had been below 0.05. Statistical analysis was performed by use of Genehunter and Sibpal software. After calculation of the logarithm of the odds (LOD) and nonparametric linkage analysis (NPL) scores our study did not show any linkage in the region analyzed. Our conclusion did not change even after only ASP were analyzed. In contrast with a previous study examining multigenerational Japanese families with IA, most Japanese ASP may not have a genetic linkage to chromosome 17cen.

Chromosomes, Human, Pair 7↗
PubMed2006

Proton magnetic resonance spectroscopy (MRS) of metastatic brain tumors: variations of metabolic profile.

BACKGROUND: Spectroscopic imaging can be helpful for the noninvasive identification of parenchymal brain tumors. The objective of the present study was the characterization of the metabolic profile of intracranial metastases, based on proton magnetic resonance spectroscopy (MRS). METHODS: One hundred and four metastatic brain tumors were evaluated by long-echo (TR, 2000 ms; TE, 136 ms) single-voxel volume-selected proton MRS. In 83 patients the tumor fraction within the MRS voxel constituted more than 50%. RESULTS: Compared to normal brain, the tumors showed statistically significant decreases of N-acetylaspartate (P < 0.0001), creatine (P < 0.0001), and the [NAA]/choline-containing compounds ratio (P < 0.0001), increases of [Cho] (P < 0.0001) and the mobile lipids/[Cr] ratio (P < 0.0001) and the lactate/[Cr] ratio (P < 0.05), and the more frequent presence of [Lip] (P < 0.0001) and [Lac] (P < 0.0001) resonances. However, the majority of these differences were lost when data for patients whose tumor fraction within the MRS voxel constituted less than 50% were analyzed separately. Determination of the predominant metabolite peak on the MR spectrum [NAA, Cho, Lip] permitted us to define three general metabolic patterns of brain metastases, which, showed statistically significant associations with the size of the neoplasm (P < 0.001), type of its contrast enhancement (P < 0.01), and the extent of perilesional edema (P < 0.05). CONCLUSION: Proton MRS can define metabolically different subsets of metastatic brain tumors, and these characteristics should be taken into consideration during the differential diagnosis of parenchymal brain lesions.

Aged↗
PubMed2006

Neurofiberscopic biopsy of tumors of the pineal region and posterior third ventricle: indications, technique, complications, and results.

OBJECTIVE: Evaluation of results of the neurofiberscopic biopsy of tumors of the pineal region and posterior third ventricle. METHODS: From 2001 to 2004, 23 patients (mean age, 30.6 yr) with tumors located in the pineal region or posterior third ventricle underwent neurofiberscopic biopsy with simultaneous third ventriculostomy. The procedure was indicated for verification of the histological diagnosis of the neoplasm, which was planned to be treated by radiotherapy and/or chemotherapy without open surgery (eight patients), establishment of the pathological diagnosis for further choice of the most appropriate treatment strategy (11 patients), differentiation of the recurrent neoplasm and radiation necrosis (two patients), and decompression of the large tumor-associated cyst (two patients). In six previously shunted patients, substitution of the ventriculoperitoneal shunt on the third ventricle stoma was performed. RESULTS: There was no postoperative mortality or permanent morbidity. In all cases, the obtained tissue sample was sufficient for pathological diagnosis. Transient postoperative complications included fever (15 patients), nausea and vomiting (three patients), and diplopia (one patient). On the long-term follow-up, delayed third ventricular stoma failure caused by tumor regrowth and scar formation was found in one patient, and dissemination of the malignant glioma through the subarachnoid space was found in another patient. CONCLUSION: Neurofiberscopic biopsy represents a useful method for sampling of tumors of the pineal region and posterior third ventricle, which can be effectively used in both previously shunted and shunt-free patients.

Adolescent↗
PubMed2006

Three-way bipolar forceps: a novel bipolar coagulator system for nerve stimulation and detection of nerve potentials.

Preoperative characterization of brain anatomy by magnetic resonance imaging and intraoperative functional characterization of the nervous system is essential in patients undergoing radical resection of brain tumors. A novel integrated system was developed combining conventional bipolar forceps with an electric stimulator and an oscilloscope. The system consists of a mechanical switching circuit allowing a wide range of electric characteristics and was designed to perform intraoperative electrophysiological studies, including functional mapping and measurements of motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs). This system achieved a significant reduction in exchange time (from 3.63+/-1.00 sec to 1.12+/-0.42 sec) between coagulation and stimulation, and reproducible measurement of MEPs from porcine limbs by cortical stimulation using the bipolar forceps. Functional mapping under awake craniotomy was carried out by cortical stimulation in patients with glioblastoma, and median nerve SEPs with high signal-to-noise ratio were elicited from the bipolar forceps on the sensory cortex of patients under general anesthesia. This integrated system is technically easy to operate and allows functional monitoring of an area that would otherwise be difficult to access using conventional methods. This three-way bipolar forceps system may reduce postoperative complications in patients undergoing neurosurgical procedures.

Adult↗
PubMed2006

Hypothalamic hamartoma associated with anterior paraclinoid aneurysm of the internal carotid artery.

A 15-year-old boy presented with a history of medically refractory gelastic seizures and cognitive impairments. Neuroimaging demonstrated a sessile type hypothalamic hamartoma, which was treated by gamma knife surgery. However, the gelastic seizures only partially decreased and the frequency of seizures remained unchanged. One year later, angiography before surgery detected anterior paraclinoid aneurysm of the left internal carotid artery. Blood pressure and endocrinological examinations showed no abnormality. Direct surgery was performed to treat the aneurysm and hamartoma. No sclerotic changes were noted in the arterial wall. The aneurysm was treated with clipping, and the hamartoma was partially removed. Postoperative course was uneventful and the gelastic seizures disappeared. No evidence for a causal relationship between the hamartoma and aneurysm was found.

Adolescent↗
PubMed2006

Using endothelial nitric oxide synthase gene polymorphisms to identify intracranial aneurysms more prone to rupture in Japanese patients.

OBJECT: Recent investigators found that the presence of three tandem polymorphisms of the endothelial nitric oxide synthase (eNOS) gene-promoter single nucleotide polymorphism (SNP) T-786C, intron-4 27-bp variable number of tandem repeats, and the G894T SNP in exon 7-was indicative of intracranial aneurysms more prone to rupture in a Caucasian patient sample. In the present study, the authors sought to determine whether the presence of these eNOS polymorphisms could indicate which Japanese patients with aneurysms were more endangered by a subarachnoid hemorrhage (SAH). METHODS: The three eNOS polymorphisms were genotyped in 297 patients with ruptured aneurysms (RAs), 108 patients with unruptured aneurysms (UAs), and 176 healthy volunteers by using polymerase chain reaction. The distribution of the variant alleles did not differ significantly (p > 0.05) between the RA group and the UA group. The frequency of the corresponding genotypes between the two groups and a haplotype analysis did not show any significant differences. Further comparisons of the RA and UA groups with the control group did not yield any significant allele or genotype frequency differences. Conclusions. These data show that the examined set of eNOS polymorphisms were not indicative of which Japanese patients with intracranial aneurysms would suffer an SAH. The presence of eNOS polymorphisms is not useful in identifying intracranial aneurysms that are more prone to rupture in a Japanese patient sample.

Adult↗
PubMed2006

[Efficacy and safety of monotherapy with temozolomide in patients with anaplastic astrocytoma at first relapse--a phase II clinical study].

The efficacy and safety of temozolomide were evaluated in 32 patients with anaplastic astrocytoma at first relapse. Temozolomide was administered orally once daily for the first five days of a 28-day cycle, at a dose of 150 or 200 mg/m(2)/day. The response rate determined by independent central review of MRI was 34% (95% confidence interval: 18.6%-53.2%), with 3 complete response and 8 partial response. The rate of "no change or better" was 91% (95% confidence interval: 75.0%-98.0%). Progression-free survival (PFS) at 6 months was 40.6%, and the median PFS was 4.1 months. The incidence of constipation (50%) and nausea (25%) was high,but these events were all mild or moderate in severity except in one subject with constipation,and could be managed with standard laxatives and antiemetics. The main laboratory test abnormalities (total incidence and incidence of grade 3/4 change) were lymphocytopenia (50%, 25%), neutropenia (47%, 6%), leukopenia (38%, 3%), thrombocytopenia (31%, 9%), and increased GPT (25%, 3%). Temozolomide was shown to have good efficacy and tolerability in patients with anaplastic astrocytoma at first relapse.

Adult↗
PubMed2005

Surgical removal of growth hormone-secreting pituitary adenomas with intensive microsurgical pseudocapsule resection results in complete remission of acromegaly.

Although some investigators recommended surgical removal of the borders between pituitary adenoma and the surrounding normal pituitary gland, there is so far little documentation of how intensive dissection of the border zone affects the actual clinical remission rate of pituitary adenomas. We investigated the precise histological characteristics of the boundary, using surgical specimens from patients who underwent intensive resection of "microsurgical pseudocapsule" of growth hormone (GH)-secreting pituitary adenomas. Furthermore, we compared the remission rate of acromegaly between subjects with (Group 1) and without (Group 2) intensive resection of microsurgical pseudocapsule in order to correlate the histological complete resection and endocrinological remission. Histologically, most adenomas were in direct contact with normal pituitary gland that formed an increased fibrous component facing the adenoma, without a true histological pseudocapsule. It was impossible to dissect the tumor at exactly the tumor--normal pituitary interface for the whole extent of the pituitary adenoma during surgery, and complete removal of the tumor inevitably included a portion of normal tissue (microsurgical pseudocapsule). The biochemical remission rate was significantly higher in Group 1 than in Group 2 (90.0 vs 61.1%), and Group 1 showed no additional postoperative pituitary hypofunction. The present results suggested that intensive resection of the microsurgical pseudocapsule is essential to accomplish histological and endocrinological total resection of the GH-secreting pituitary adenomas for remission of acromegaly.

Adult↗