Prevalence and Incidence of Dementia in South Korea:A Nationwide Analysis of the National Health Insurance Service Senior Cohort

Background@#and Purpose Dementia is rapidly becoming more common in the elderly population of South Korea, and there are regional difference in its demographics. This study investigated the trajectories in the prevalence and incidence of dementia based on the Seoul metropolitan area and other areas in South Korea using big data from the National Health Insurance Service (NHIS). @*Methods@#We examined a population-based elderly cohort obtained from the NHIS Senior Cohort (NHIS-SC) data set that comprises approximately half a million recipients of medical insurance in South Korea during 2003–2015. The age-standardized prevalence and incidence of dementia as well as their trajectories from 2003 were estimated. Regional differences in these rates between Seoul metropolitan area and other areas were also analyzed. @*Results@#The standardized prevalence of dementia per 100,000 increased significantly from 178.11 in 2003 to 5,319.01 in 2015 (p<0.001). The standardized prevalence of dementia was higher in other areas than in Seoul metropolitan area. The standardized incidence of dementia per 100,000 person-years also increased significantly, from 126.41 in 2003 to 2,218.25 in 2015 (p<0.001). The standardized incidence of dementia was similarly higher in other areas than in Seoul metropolitan area (p<0.001). @*Conclusions@#This study has shown that the standardized prevalence and incidence of dementia increased steadily from 2003 to 2015 in South Korea based on the NHIS-SC data set, and differed between Seoul metropolitan area and other areas.

Prevalence and Incidence of Dementia in South Korea:A Nationwide Analysis of the National Health Insurance Service Senior Cohort

Background@#and Purpose Dementia is rapidly becoming more common in the elderly population of South Korea, and there are regional difference in its demographics. This study investigated the trajectories in the prevalence and incidence of dementia based on the Seoul metropolitan area and other areas in South Korea using big data from the National Health Insurance Service (NHIS). @*Methods@#We examined a population-based elderly cohort obtained from the NHIS Senior Cohort (NHIS-SC) data set that comprises approximately half a million recipients of medical insurance in South Korea during 2003–2015. The age-standardized prevalence and incidence of dementia as well as their trajectories from 2003 were estimated. Regional differences in these rates between Seoul metropolitan area and other areas were also analyzed. @*Results@#The standardized prevalence of dementia per 100,000 increased significantly from 178.11 in 2003 to 5,319.01 in 2015 (p<0.001). The standardized prevalence of dementia was higher in other areas than in Seoul metropolitan area. The standardized incidence of dementia per 100,000 person-years also increased significantly, from 126.41 in 2003 to 2,218.25 in 2015 (p<0.001). The standardized incidence of dementia was similarly higher in other areas than in Seoul metropolitan area (p<0.001). @*Conclusions@#This study has shown that the standardized prevalence and incidence of dementia increased steadily from 2003 to 2015 in South Korea based on the NHIS-SC data set, and differed between Seoul metropolitan area and other areas.

Optimal effective-site concentration of remifentanil for sedation during plate removal of maxilla

BACKGROUND: Removal of the plate following Le Fort I osteotomy and BSSO (bilateral sagittal split osteotomy) is a common procedure. However, patients who undergo plate removal experience intense pain and discomfort. This study investigated the half-maximal effective concentration (Ce50 ) of remifentanil in the prevention of plate removal pain under sedation using dexmedetomidine. METHODS: The study evaluated 18 patients, between 18 and 35 years of age, scheduled for elective surgery. Remifentanil infusion was initiated after sedation using dexmedetomidine, and started at a dose of 1.5 ng/mL on the first patient via target-controlled infusion (TCI). Patients received a loading dose of 1.0 µg/kg dexmedetomidine over 10 min, followed by a maintenance dose of 0.7 µg/kg/h. When the surgeon removed the plate, the patient Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score was observed. RESULTS: The Ce of remifentanil ranged from 0.9 to 2.1 ng/mL for the patients evaluated. The estimated effect-site concentrations of remifentanil associated with a 50% and 95% probability of reaching MOAA/S score of 3 were 1.28 and 2.51 ng/mL, respectively. CONCLUSIONS: Plate removal of maxilla can be successfully performed without any pain or adverse effects by using the optimal remifentanil effect-site concentration (Ce50 , 1.28 ng/mL; Ce95 , 2.51 ng/mL) combined with sedation using dexmedetomidine.

Pathogenic and phylogenetic characteristics of non-O157 Shiga toxin-producing Escherichia coli isolates from retail meats in South Korea

Herein, we report the pathogenic and phylogenetic characteristics of seven Shiga toxin (Stx)-producing Escherichia coli (STEC) isolates from 434 retail meats collected in Korea during 2006 to 2012. The experimental analyses revealed that all isolates (i) were identified as non-O157 STEC, including O91:H14 (3 isolates), O121:H10 (2 isolates), O91:H21 (1 isolate), and O18:H20 (1 isolate), (ii) carried diverse Stx subtype genes (stx₁, stx(2c), stx(2e), or stx₁ + stx(2b)) whose expression levels varied strain by strain, and (iii) lacked the locus of enterocyte effacement (LEE) pathogenicity island, a major virulence factor of STEC, but they possessed one or more alternative virulence genes encoding cytotoxins (Cdt and SubAB) and/or adhesins (Saa, Iha, and EcpA). Notably, a significant heterogeneity in glutamate-induced acid resistance was observed among the STEC isolates (p < 0.05). In addition, phylogenetic analyses demonstrated that all three STEC O91:H14 isolates were categorized into sequence type (ST) 33, of which two beef isolates were identical in their pulsotypes. Similar results were observed with two O121:H10 pork isolates (ST641; 88.2% similarity). Interestingly, 96.0% of the 100 human STEC isolates collected in Korea during 2003 to 2014 were serotyped as O91:H14, and the ST33 lineage was confirmed in approximately 72.2% (13/18 isolates) of human STEC O91:H14 isolates from diarrheal patients.

A Case of Scrub Typhus Related Encephalopathy Presenting as Rapidly Progressive Dementia

BACKGROUND: An infection known to be a major cause of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). Rapidly progressive dementia is a neurological condition in which dementia progresses in a short period of time. CASE REPORT: We report on a 78-year-old woman presenting with a rapid decline in cognitive function resulting from a scrub typhus infection. Diffusion weighted images showed a signal intensity at the splenium, and subcortical white matter of both hemispheres suggesting MERS. On the neuropsychological test, the patient showed frontal executive dysfunction. CONCLUSIONS: This case suggests that diagnosticians should consider the possibility that a MERS patient with a rapidly cognitive decline could have a scrub typhus infection because early diagnosis of scrub typhus is very important in this aspect of the treatment.

Hippocampal Lesions of Diffusion Weighted Magnetic Resonance Image in Patients with Headache without Symptoms of Transient Global Amnesia

BACKGROUND: The dot-like hippocampal signal intensity in diffusion-weighted MR images is well-known as a characteristic imaging feature in transient global amnesia, a neurological syndrome in which sudden forward-and-backward memory loss occurs that is slowly recovered within 24 hours. We here report on patients with this dot-like hippocampal hyperintensity who did not present with anterograde amnesia except for headaches. CASE REPORT: Two women without a specific medical history presented with sudden-onset headaches on the same day. Neither had any trauma or infection history before the symptom or any sudden emotional or postural changes. Brain MRI showed tiny hippocampal high signal intensity on diffusion-weighted images (DWI). CONCLUSIONS: Dot-like hippocampal lesions seen on DWI may be present without memory impairment, and more studies are needed to determine whether there is any association with headache as in this case.

Protective effects of remifentanil against H₂O₂-induced oxidative stress in human osteoblasts

BACKGROUND: Bone injury is common in many clinical situations, such as surgery or trauma. During surgery, excessive reactive oxygen species (ROS) production decreases the quality and quantity of osteoblasts. Remifentanil decreases ROS production, reducing oxidative stress and the inflammatory response. We investigated remifentanil's protective effects against H₂O₂-induced oxidative stress in osteoblasts. METHODS: To investigate the effect of remifentanil on human fetal osteoblast (hFOB) cells, the cells were incubated with 1 ng/ml of remifentanil for 2 h before exposure to H2O2. For induction of oxidative stress, hFOB cells were then treated with 200 µM H₂O₂ for 2 h. To evaluate the effect on autophagy, a separate group of cells were incubated with 1 mM 3-methyladenine (3-MA) before treatment with remifentanil and H₂O₂. Cell viability and apoptotic cell death were determined via MTT assay and Hoechst staining, respectively. Mineralized matrix formation was visualized using alizarin red S staining. Western blot analysis was used to determine the expression levels of bone-related genes. RESULTS: Cell viability and mineralized matrix formation increased on remifentanil pretreatment before exposure to H₂O₂-induced oxidative stress. As determined via western blot analysis, remifentanil pretreatment increased the expression of bone-related genes (Col I, BMP-2, osterix, and TGF-β). However , pretreatment with 3-MA before exposure to remifentanil and H₂O₂ inhibited remifentanil's protective effects on hFOB cells during oxidative stress. CONCLUSIONS: We showed that remifentanil prevents oxidative damage in hFOB cells via a mechanism that may be highly related to autophagy. Further clinical studies are required to investigate its potential as a therapeutic agent.

Dexmedetomidine attenuates H₂O₂-induced cell death in human osteoblasts

BACKGROUND: Reactive oxygen species play critical roles in homeostasis and cell signaling. Dexmedetomidine, a specific agonist of the α₂-adrenoceptor, has been commonly used for sedation, and it has been reported to have a protective effect against oxidative stress. In this study, we investigated whether dexmedetomidine has a protective effect against H₂O₂-induced oxidative stress and the mechanism of H₂O₂-induced cell death in normal human fetal osteoblast (hFOB) cells. METHODS: Cells were divided into three groups: control group—cells were incubated in normoxia without dexmedetomidine, hydrogen peroxide (H2O2) group—cells were exposed to H₂O₂ (200 µM) for 2 h, and Dex/H₂O₂ group—cells were pretreated with dexmedetomidine (5 µM) for 2 h then exposed to H₂O₂ (200 µM) for 2 h. Cell viability and apoptosis were evaluated. Osteoblast maturation was determined by assaying bone nodular mineralization. Expression levels of bone-related proteins were determined by western blot. RESULTS: Cell viability was significantly decreased in the H₂O₂ group compared with the control group, and this effect was improved by dexmedetomidine. The Hoechst 33342 and Annexin-V FITC/PI staining revealed that dexmedetomidine effectively decreased H₂O₂-induced hFOB cell apoptosis. Dexmedetomidine enhanced the mineralization of hFOB cells when compared to the H₂O₂ group. In western blot analysis, bone-related protein was increased in the Dex/H₂O₂ group. CONCLUSIONS: We demonstrated the potential therapeutic value of dexmedetomidine in H₂O₂-induced oxidative stress by inhibiting apoptosis and enhancing osteoblast activity. Additionally, the current investigation could be evidence to support the antioxidant potential of dexmedetomidine in vitro.

A Validation Study of Korean Version of Personality Beliefs Questionnaire-Short Form (PBQ-SF) / 신경정신의학

OBJECTIVES: The Personality Belief Questionnaire-Short Form (PBQ-SF) is a self-report instrument for assessment of dysfunctional beliefs based on Beck's cognitive formulations of personality disorders. The aims of this study was to examine the reliability and validity of the Korean version of PBQ-SF in clinical samples. METHODS: The Korean version of PBQ-SF was examined in 115 participants (50 patients with personality disorder and 65 patients without personality disorder). All participants were assessed for personality disorder using the semi-structured clinical interview of the Personality Assessment Schedule. The construction validity was examined by correlation with Beck Depression Inventory, Spielberger State-Trait Anxiety Inventory, and Neuroticism-Extraversion-Openness Five-Factor Inventory neuroticism scales. Twenty four randomly sampled patients were examined for the test-retest reliability. RESULTS: The Korean version of PBQ-SF showed good internal consistency [Cronbach's alpha=0.73 (schizoid)-0.92 (paranoid)] and test-retest reliability [r=0.74 (narcissistic)-0.92 (paranoid)]. The PBQ-SF was correlated with depression, anxiety, and neuroticism. The overall subscales of PBQ-SF were correlated with Diagnostic and Statistical Manual of Mental Disorders based diagnosis of personality disorders. CONCLUSION: Consistent with previous findings using the Korean full version of PBQ as well as the English version of PBQ-SF, our results support that the Korean version of PBQ-SF is a reliable and valid instrument for assessment of dysfunctional beliefs associated with personality pathology.

Neurosyphilis Mimicking Creutzfeldt-Jakob Disease

BACKGROUND: As rapidly progressive dementia (RPD), general paresis and Creutzfeldt-Jakob disease (CJD) may have overlapping clinical presentation due to a wide variety of clinical manifestations. CASE REPORT: A 57-year-old man presented with rapid progressive cognitive decline, behavioral change, ataxic gait, tremor and pyramidal signs for 3 months. In addition to these multiple systemic involvements, positive result for the cerebrospinal fluid (CSF) 14-3-3 protein tentatively diagnosed him as probable CJD. However, due to increased serum rapid plasma reagin, venereal disease research laboratory, and fluorescent treponemal antibody-absorption reactivity in CSF, the final diagnosis was changed to general paresis. CONCLUSIONS: A patient with RPD needs to be carefully considered for differential diagnosis, among a long list of diseases. It is important to rule out CJD, which is the most frequent in RPD and is a fatal disease with no cure. Diagnostic criteria or marker of CJD, such as 14-3-3 protein, may be inconclusive, and a typical pattern in diffusion-weighted imaging is important to rule out other reversible diseases.

Enhancement of beta-Glucosidase Activity from a Brown Rot Fungus Fomitopsis pinicola KCTC 6208 by Medium Optimization

beta-Glucosidase, which hydrolyzes cellobiose into two glucoses, plays an important role in the process of saccharification of the lignocellulosic biomass. In this study, we optimized the activity of beta-glucosidase of brown-rot fungus Fomitopsis pinicola KCTC 6208 using the response surface methodology (RSM) with various concentrations of glucose, yeast extract and ascorbic acid, which are the most significant nutrients for activity of beta-glucosidase. The highest activity of beta-glucosidase was achieved 3.02% of glucose, 4.35% of yeast extract, and 7.41% ascorbic acid where ascorbic acid was most effective. The maximum activity of beta-glucosidase predicted by the RSM was 15.34 U/mg, which was similar to the experimental value 14.90 U/mg at the 16th day of incubation. This optimized activity of beta-glucosidase was 23.6 times higher than the preliminary activity value, 0.63 U/mg, and was also much higher than previous values reported in other fungi strains. Therefore, a simplified medium supplemented with a cheap vitamin source, such as ascorbic acid, could be a cost effective mean of increasing beta-glucosidase activity.

Proton Beam Radiotherapy for Pediatric Gliomas: Early Outcomes and Dose Comparison / 임상소아혈액종양

BACKGROUND: Proton beam radiotherapy (PBT) has shown to provide high radiation dose to tumors and to save surrounding normal tissues because of its physical characteristics, Bragg peak. In the current study, we report the early outcomes for pediatric patients with intracranial gliomas treated with PBT and compared PBT plan (pencil beam scanning and double scattering) with intensity modulated radiotherapy (IMRT) plan and three dimensional-conformal radiotherapy (3D-CRT) plan. METHODS: Clinical data from 18 consecutive children with intracranial gliomas who underwent PBT from May 2007 to April 2012 was collected. The median follow-up duration was 16 months (range 6-69). RESULTS: There were 9 patients with brain stem glioma, 2 patients with optic pathway glioma, 2 patients with low grade glioma (LGG), 2 patients with anaplastic astrocytoma (AA) and 3 patients with glioblastoma multiforme (GBM). The median overall survival for patients with brain stem glioma was 11 months. Patients with optic pathway glioma, LGG or AA were all alive without progression except one patient. Among patients with GBM, one patient had no evidence of disease 25 months after PBT. When PBT plan was compared to those of IMRT and 3D-CRT for patients with LGG or AA and one patient with brain stem glioma by DVH analysis, PBT showed better sparing effect on normal tissue compared to IMRT and 3D-CRT, especially in low dose area. CONCLUSION: PBT could be delivered safely and effectively to pediatric patients with gliomas. For confirming the clinical benefits of PBT, further follow-up is necessary.

Proton Beam Radiotherapy for Pediatric Gliomas: Early Outcomes and Dose Comparison / 임상소아혈액종양

BACKGROUND: Proton beam radiotherapy (PBT) has shown to provide high radiation dose to tumors and to save surrounding normal tissues because of its physical characteristics, Bragg peak. In the current study, we report the early outcomes for pediatric patients with intracranial gliomas treated with PBT and compared PBT plan (pencil beam scanning and double scattering) with intensity modulated radiotherapy (IMRT) plan and three dimensional-conformal radiotherapy (3D-CRT) plan.METHODS: Clinical data from 18 consecutive children with intracranial gliomas who underwent PBT from May 2007 to April 2012 was collected. The median follow-up duration was 16 months (range 6-69).RESULTS: There were 9 patients with brain stem glioma, 2 patients with optic pathway glioma, 2 patients with low grade glioma (LGG), 2 patients with anaplastic astrocytoma (AA) and 3 patients with glioblastoma multiforme (GBM). The median overall survival for patients with brain stem glioma was 11 months. Patients with optic pathway glioma, LGG or AA were all alive without progression except one patient. Among patients with GBM, one patient had no evidence of disease 25 months after PBT. When PBT plan was compared to those of IMRT and 3D-CRT for patients with LGG or AA and one patient with brain stem glioma by DVH analysis, PBT showed better sparing effect on normal tissue compared to IMRT and 3D-CRT, especially in low dose area.CONCLUSION: PBT could be delivered safely and effectively to pediatric patients with gliomas. For confirming the clinical benefits of PBT, further follow-up is necessary.

A Case of Xanthogranuloma on the Subungual Area of an Adult / 대한피부과학회지

No abstract available.

Treatment Results of CyberKnife Radiosurgery for Patients with Primary or Recurrent Non-Small Cell Lung Cancer / 대한방사선종양학회지

PURPOSE: Recently, the use of radiosurgery as a local therapy in patients with early stage non-small cell lung cancer has become favored over surgical resection. To evaluate the efficacy of radiosurgery, we analyzed the results of stereotactic body radiosurgery in patients with primary or recurrent non-small cell lung cancer. MATERIALS AND METHODS: We reviewed medical records retrospectively of total 24 patients (28 lesions) with non-small cell lung cancer (NSCLC) who received stereotactic body radiosurgery (SBRT) at Inha University Hospital. Among the 24 patients, 19 had primary NSCLC and five exhibited recurrent disease, with three at previously treated areas. Four patients with primary NSCLC received SBRT after conventional radiation therapy as a boost treatment. The initial stages were IA in 7, IB in 3, IIA in 2, IIB in 2, IIIA in 3, IIIB in 1, and IV in 6. The T stages at SBRT were T1 lesion in 13, T2 lesion in 12, and T3 lesion in 3. 6MV X-ray treatment was used for SBRT, and the prescribed dose was 15~60 Gy (median: 50 Gy) for PTV1 in 3~5 fractions. Median follow up time was 469 days. RESULTS: The median GTV was 22.9 mL (range, 0.7 to 108.7 mL) and median PTV1 was 65.4 mL (range, 5.3 to 184.8 mL). The response rate at 3 months was complete response (CR) in 14 lesions, partial response (PR) in 11 lesions, and stable disease (SD) in 3 lesions, whereas the response rate at the time of the last follow up was CR in 13 lesions, PR in 9 lesions, SD in 2 lesions, and progressive disease (PD) in 4 lesions. Of the 10 patients in stage I, one patient died due to pneumonia, and local failure was identified in one patient. Of the 10 patients in stages III-IV, three patients died, local and loco-regional failure was identified in one patient, and regional failure in 2 patients. Total local control rate was 85.8% (4/28). Local recurrence was recorded in three out of the eight lesions that received below biologically equivalent dose 100 Gy10. Among 20 lesions that received above 100 Gy10, only one lesion failed locally. There was a higher recurrence rate in patients with centrally located tumors and T2 or above staged tumors. CONCLUSION: SBRT using a CyberKnife was proven to be an effective treatment modality for early stage patients with NSCLC based on high local control rate without severe complications. SBRT above total 100 Gy10 for peripheral T1 stage patients with NSCLC is recommended.

Comparing Concurrent Chemoradiotherapy to Chemotherapy Alone for Locally Advanced Unresectable Pancreatic Cancer / 대한방사선종양학회지

PURPOSE: Concurrent chemoradiotherapy (CCRT) is the standard treatment for locally advanced unresectable pancreatic cancer. However, the introduction of gemcitabine and the recognition of a benefit in patients with advanced disease stimulated the design of trials that compare chemotherapy alone to concurrent chemoradiation. Therefore, we evaluated role of CCRT for locally advanced unresectable pancreatic cancer. MATERIALS AND METHODS: We carried out a retrospective analysis of treatment results for patients with locally advanced unresectable pancreatic cancer between January 2000 and January 2008. The radiation was delivered to the primary tumor and regional lymph nodes with a 1~2 cm margin at a total dose of 36.0~59.4 Gy (median: 54 Gy). The chemotherapeutic agent delivered with the radiation was 5-FU (500 mg/m2). The patients who underwent chemotherapy alone received gemcitabine (1,000 mg/m2) alone or gemcitabine with 5-FU. The follow-up period ranged from 2 to 38 months. The survival and prognostic factors were analyzed using Kaplan-Meier method and log-rank test, respectively. RESULTS: Thirty-four patients received concurrent chemoradiotherapy, whereas 21 patients received chemotherapy alone. The median survival time was 12 months for CCRT patients, compared to 11 months for chemotherapy alone patients (p=0.453). The median progression-free survival was 8 months for CCRT patients, compared to 5 months for chemotherapy alone patients (p=0.242). The overall response included 9 partial responses for CCRT and 1 partial response for chemotherapy alone. In total, 26% of patients from the CCRT group experienced grade 3~4 bowel toxicity. In contract, no grade 3~4 bowel toxicity was observed in the chemotherapy alone group. The significant prognostic factors of overall survival were lymph node status, high CA19-9, and tumor location. CONCLUSION: The response rate and progression-free survival were more favorable in the CCRT group, when compared with the chemotherapy alone group. Therefore, radiation therapy seems to be an effective tool for local tumor control.

Detection method of proximal caries using line profile in digital intra-oral radiography / 대한구강악안면방사선학회지

PURPOSE: The purpose of this study was to investigate how to detect proximal caries using line profile and validate linear measurements of proximal caries lesions by basic digital manipulation of radiographic images. MATERIALS AND METHODS: The X-ray images of control group (15) and caries teeth (15) from patients were used. For each image, the line profile at the proximal caries-susceptible zone was calculated. To evaluate the contrast as a function of line profile to detect proximal caries, a difference coefficient (D) that indicates the relative difference between caries and sound dentin or intact enamel was measured. RESULTS: Mean values of D were 0.0354+/-0.0155 in non-caries and 0.2632+/-0.0982 in caries (p<0.001). CONCLUSION: The mean values of caries group were higher than non-caries group and there was correlation between proximal dental caries and D. It is demonstrated that the mean value of D from caries group was higher than that of control group. From the result, values of D possess great potentiality as a new detection parameter for proximal dental caries.

Aneurysmal bone cyst of the mandibular condyle with condylar neck fracture / 대한구강악안면방사선학회지

Aneurysmal bone cyst (ABC) is relatively rare, non-neoplastic expansile lesion of bone. The case of a 15-year-old male with a ABC of the left mandibular condyle is presented. Panoramic radiograph showed a unilocular radiolucency with thinned coritces and a subcondylar fracuture which was due to the trauma. Computed tomography (CT) revealed expansile lesion which had similar attenuation soft tissue. The patient was treated surgically including iliac crestal bone graft.

Detection for demineralization of dental hard tissues using index-sequenced radiographs / 대한구강악안면방사선학회지

PURPOSE : The purpose of this study was to develop the radiographic technique for detecting the demineralization which is known as indication of dental caries MATERIALS AND METHODS : This technique was based on the comparing of multiple radiographs which was irradiated by multiple X-ray spectra. For the meaningful comparing, the multiple radiographs were reconstructed to the dosimetrically consistent images using a standard material. The difference of resulting images of same target with multiple spectra represents the difference of response of material as regards the spectra. RESULTS : We have found about 10% of demineralization of dental hard tissues particularly in the proximal region through the analyzing of differences. CONCLUSION : Most intriguing thing in this investigation was that the method to analyze difference shows us to an anatomic structure of dental hard tissues even if absolute values of optical density were excluded during the procedures.

The Effect of Extracellular Glutamate Release on Repetitive Transient Ischemic Injury in Global Ischemia Model

During operations, neurosurgeons usually perform multiple temporary occlusions of parental artery, possibly resulting in the neuronal damage. It is generally thought that neuronal damage by cerebral ischemia is associated with extracellular concentrations of the excitatory amino acids. In this study, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion (VO) model to compare between single occlusion and repeated transient occlusions within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flowmetry simultaneously with cortical glutamate level measured by amperometric biosensor. From real time monitoring of glutamate release in 11 VO model, the change of extracellular glutamate level in repeated transient occlusion group was smaller than that of single occlusion group, and the onset time of glutamate release in the second ischemic episode of repeated occlusion group was delayed compared to the first ischemic episode which was similar to that of single 10 min ischemic episode. These results suggested that repeated transient occlusion induces less glutamate release from neuronal cell than single occlusion, and the delayed onset time of glutamate release is attributed to endogeneous protective mechanism of ischemic tolerance.