Yasuyuki Iguchi

The Jikei University School of Medicine, Edo, Tōkyō, Japan

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Publications (164)440.45 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A 30-year-old man presented with headache, left hemiparesis, and uncal herniation. Magnetic resonance imaging showed acute infarction in the right middle cerebral artery (MCA). Lifesaving craniotomy proceeded because of the uncal herniation. Assessment of brain tissue led to a diagnosis of MCA dissection. His skin biopsy showed ultrastructural abnormalities of dermal connective tissue. This is the unique case that dissection was diagnosed from both a biopsy specimen of the MCA and the dermal connective tissue. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 08/2015; DOI:10.1016/j.jstrokecerebrovasdis.2015.04.008 · 1.99 Impact Factor
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    ABSTRACT: A 73-year-old woman was admitted with severe burning pain, hyperesthesia, and weakness in the right lower extremity. The patient had undergone radio- and chemotherapy after surgery for cervical cancer 17 years earlier. We diagnosed radiation-induced lumbosacral plexopathy because of conduction block in the deep peroneal nerve and myokymic discharge in the tibialis anterior muscle. Pelvic computed tomography and magnetic resonance imaging ruled out recurrent tumor and nerve-compressing lesions. Although radiation-induced lumbosacral plexopathy is usually characterized by lower motor neuron syndrome, we report a rare case presenting with severe pain and hyperesthesia.
    07/2015; DOI:10.5692/clinicalneurol.cn-000706
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    ABSTRACT: Carotid duplex ultrasonography (CUS) has been used to identify reversed vertebral artery flow (RVAF) at the extracranial cervical artery in some patients with subclavian steal syndrome. However, the characteristics of intracranial RVAF as evaluated by transcranial color flow imaging (TC-CFI), which can examine intracranial hemodynamics in a real-time and noninvasive fashion, remain unclear. The goal of this study was to analyze the prevalence of intracranial RVAF and its associated clinical characteristics. Subjects were consecutive patients who underwent TC-CFI and CUS. We evaluated blood flow in both intracranial vertebral arteries (VAs) from the suboccipital echo window using TC-CFI. RVAF was defined as a flow signal directed toward the probe. We calculated the prevalence of intracranial RVAF in our subjects. Then, we investigated vascular condition (ie, site of lesion, stenosis, occlusion, and dissection) using magnetic resonance angiography, computed tomography angiography , and CUS in patients with intracranial RVAF. Seven hundred twenty patients (508 men; median age, 73 years) were included in this study from September 2007 to March 2013. Intracranial RVAF was seen in 12 patients (1.7%; 11 men; median age, 61 years). Among the 12 patients with intracranial RVAF, 8 patients (67%) had ischemia of the vertebrobasilar territory with distal VA occlusion, according to CUS. Of those patients, 6 (75%) had dissection of the VA. TC-CFI detected intracranial RVAF in 1.7% of consecutive examinations in our facility. In vertebrobasilar territory stroke patients with intracranial RVAF, VA dissection may contribute to the development of stroke. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 06/2015; DOI:10.1016/j.jstrokecerebrovasdis.2015.03.044 · 1.99 Impact Factor
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    ABSTRACT: This study aimed to examine whether the volume of the olfactory bulbs and tracts (OB & T) on magnetic resonance imaging (MRI) is useful for differentiating Parkinson's disease (PD) from PD-related disorders. The study group comprised 13 patients with PD, 11 with multiple system atrophy (MSA), five with progressive supranuclear palsy, and five with corticobasal degeneration (PSP/CBD). All patients were evaluated using the odor stick identification test for Japanese (OSIT-J), (123)I-meta-iodobenzylguanidine (MIBG) scintigraphy, and brain MRI. OB & T areas on 1-mm-thick coronal images were measured and summed for volumes. We examined relationships between olfactory function and volume, and cardiovascular dysautonomia. We defined the cut-off values for OSIT-J score or MIBG uptake and OB & T volume to discriminate PD from PD-related disorders and calculated the proportional rate of PD in four categorized groups. OB & T volume was smaller in PD than in MSA or PSP/CBD (p < 0.05 each). The cut-off for detecting PD patients was OSIT-J score <8, heart/mediastinum ratio <1.6, and OB & T volume <270 mm(3). In the group with OSIT-J score <8 and OB & T volume <270 mm(3), the proportion of PD patients among all patients with PD-related disorders was 91%. The rate of probable PD gradually increased as OSIT-J score and OB & T volume decreased (p < 0.001). Although preliminary, these data obtained from a combined morphological and functional evaluation of OB or cardiovascular dysautonomia could be useful for further differential of PD and other PD-related disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Parkinsonism & Related Disorders 05/2015; 21(7). DOI:10.1016/j.parkreldis.2015.05.001 · 4.13 Impact Factor
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    ABSTRACT: Little is known about the ill effects of concurrent obstructive sleep apnea (OSA) on the symptoms of myasthenia gravis (MG). We report a case of generalized MG with OSA in which MG symptoms improved dramatically following initiation of continuous positive airway pressure (CPAP) therapy. A 42-year-old man was admitted with generalized MG. He was found to be snoring loudly during sleep and then diagnosed with OSA by polysomnography. CPAP therapy contributed to immediate improvements in not only apnea-hypopnea index (70.6 to 20.9), but also the MG-specific activities of daily living scale (10 to 1) and quantitative MG scale (21 to 8). We suggest that when an MG patient is obese and suspected to have sleep problems, examinations to detect OSA should be conducted. If OSA is diagnosed, CPAP therapy may also improve the MG symptoms of the patient.This article is protected by copyright. All rights reserved.
    04/2015; DOI:10.1111/ncn3.12003
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    ABSTRACT: Case presentationAn 86-year-old, right-handed man was admitted to our hospital 3 h after onset of a disturbance of consciousness. He had a history of hypertension. His blood pressure was 170/106 mmHg, and heart rate was 96 beats/min with a regular rhythm. Neurological examination revealed a disturbance of consciousness, aphasia, and right unilateral spatial neglect. His muscle strength was weak on his right side. The total National Institute of Health stroke scale score on admission was 16. Laboratory data showed that the D-dimer was 5.2 μg/mL (normal, 1a). DWI also indicated subacute (and apparently asymptomatic) infarctions in the right occipital lobe and cerebellum (Fig. 1b, c). Acute stroke was diagnosed, and intravenous (IV) recombinant tissue plasminogen activator (rt-PA) therapy was started 4.2 h after symptom onset. ...
    Neurological Sciences 03/2015; 36(6). DOI:10.1007/s10072-015-2138-9 · 1.50 Impact Factor
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    ABSTRACT: For safe and efficient sonothrombolysis therapies, accurate estimation of ultrasound transmittance through the human skull is essential. The present study clarifies uncertainty surrounding this transmittance and experimentally verifies the equalization of transmittance through the modulation of ultrasound frequency. By changing three factors (ultrasound frequency, the thickness of a bone-phantom plate, and the distance between a transducer and a bone-phantom plate), we measured the intensity of ultrasound passing through the plate. Two activating methods, sinusoidal waves at 500kHz and modulated waves, were compared. When we changed (1) the distance between a transducer and a bone-phantom plate and (2) the thickness of the bone-phantom plate, ultrasound transmittance through the plates substantially fluctuated. The substantial fluctuation in transmittance was observed also for a cut piece of human temporal skull bone. This fluctuation significantly declined for the modulated wave. In conclusion, modulation of ultrasound frequency can equalize the transmittance with an approximately 30-65% fluctuation drop and an approximately 40% fluctuation drop for a bone-phantom plate and for a cut piece of skull bone, respectively. By using modulated waves, we can develop safer and more effective sonothrombolysis therapies. Copyright © 2015 Elsevier B.V. All rights reserved.
    Ultrasonics 02/2015; 59. DOI:10.1016/j.ultras.2015.01.017 · 1.81 Impact Factor
  • Shinji Miyagawa · Ayumi Arai · Hidetaka Mitsumura · Yasuyuki Iguchi
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    ABSTRACT: A patient started anticoagulation for secondary prevention of stroke, achieving a prothrombin time-international normalized ratio within the optimal therapeutic range. The patient subsequently complained of pain in the left thigh on hospital day 25, and ultrasonography showed a large intramuscular hematoma in the left hamstring. The intramuscular hematoma gradually reduced without surgical intervention. Ultrasound examination plays an important role in precisely diagnosing intramuscular hematoma and monitoring changes in hematoma size.
    01/2015; 55(5):353-5. DOI:10.5692/clinicalneurol.cn-000639
  • Japanese Journal of Neurosurgery 01/2015; 24(4):226-231. DOI:10.7887/jcns.24.226
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    ABSTRACT: An 85-year-old woman came to our hospital due to an inability to live independently from a decline in her activities of daily living. Neurologically, she showed no focal signs, but multiple acute ischemic lesions were evident in the posterior circulation on magnetic resonance imaging. Occlusion of the right intracranial vertebral artery (VA) and stenosis of the left intracranial VA were detected on magnetic resonance angiography (MRA). Carotid duplex ultrasonography (CUS) showed a flow pattern with occlusion of the right VA before the branching of the posterior inferior cerebellar artery. Based upon antegrade flow in the right intracranial VA as evaluated on transcranial color flow imaging, the distal VA territory might have been maintained via collateral flow. With antiplatelet therapy and intravenous injection of argatroban, the patient’s activity gradually improved to the same level as before admission. Recanalization of the right VA was seen on MRA and CUS at 14 days after admission. Reduced cerebellar blood flow due to VA occlusion was thought to be associated with the mechanism affecting her activity levels. Follow-up ultrasonography was useful for evaluating changes in intracranial hemodynamics in this patient who demonstrated neurological improvement.
    Neurosonology 01/2015; 28(1):21-24. DOI:10.2301/neurosonology.28.21
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    ABSTRACT: Background The goal of this study was to investigate the relationship between white matter lesions on magnetic resonance imaging and flow parameters in the middle cerebral artery (MCA) measured by transcranial color flow imaging. Methods Patients with acute ischemic stroke or transient ischemic attack were included. The relationship between severities of periventricular hyperintensity (PVH) and ultrasonographic parameters in the MCA was investigated. The frequency of PVH was calculated for different categories according to the presence or absence of 2 considerable parameters according to the value of area under the receiver operating characteristic curve. Results MCA flow was successfully measured in 203 temporal windows among 124 patients. After determining the cutoff value of end-diastolic velocity (EDV) and pulsatility index (PI) for the presence of PVH, 4 different categories were established: Category A, EDV more than 40 cm/second and PI less than .7; Category B, EDV more than 40 cm/second and PI more than .7; Category C, EDV less than 40 cm/second and PI less than .7; and Category D, EDV less than 40 cm/second and PI more than .7. The prevalence of PVH gradually increased along with category (P < .01). Conclusions The evaluation of MCA parameters using the combination of PI and EDV may be useful for the prediction of PVH.
    Journal of Stroke and Cerebrovascular Diseases 10/2014; 24(1). DOI:10.1016/j.jstrokecerebrovasdis.2014.07.027 · 1.99 Impact Factor
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    ABSTRACT: Objective: The usefulness of conventional magnetic resonance imaging (C-MRI) for diagnosing amyotrophic lateral sclerosis (ALS) remains controversial. The aim of this study was to investigate the utility of C-MRI in identifying ALS, specifically the association between corticospinal tract (CST) hyperintensity on C-MRI and clinical characteristics in patients with ALS. Methods: Between June 2008 and April 2012, we retrospectively enrolled consecutive patients diagnosed with sporadic ALS who underwent C-MRI. Patients with ALS were classified as definite-phase ALS (D-ALS) and indefinite-phase ALS (ID-ALS). We focused on the hyperintensity of T2-weighted images in the CST in patients with ALS. Based on the MRI results, we divided patients into two groups: a positive CST group showing CST hyperintensity; and a negative CST group with no such findings. Clinical characteristics of the two groups were compared. Results: Seventeen patients (median age, 62 years; 8 women, 9 men) were enrolled in this study, with D-ALS in eight (47%) and ID-ALS in nine (53%). Eight patients (47%) showed CST positivity. The rate of CST positivity was higher in patients with D-ALS (75%) than in patients with ID-ALS (22%, p = 0.03). Conclusions: CST positivity appears significantly increased in D-ALS patients. C-MRI can play an important role in diagnosing ALS.
    Clinical Neurology and Neurosurgery 10/2014; 127C:1-4. DOI:10.1016/j.clineuro.2014.09.011 · 1.25 Impact Factor
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    ABSTRACT: A 49-year-old man with a 16-year history of adult-onset X-linked adrenoleukodystrophy (X-ALD) was admitted because of aspiration pneumonia. He was comatose with obvious akinesia and positive plantar reflexes. Magnetic resonance imaging (MRI) on admission showed abnormal intensities in the middle cerebellar peduncles, pons and internal capsule (Fig.1).This article is protected by copyright. All rights reserved.
    10/2014; 3(1). DOI:10.1111/ncn3.131
  • Yasuyuki Iguchi · Hideki Mitsumura · Teppei Komatsu
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    ABSTRACT: Objective Although previous randomized clinical trials established a basis for lipid guidelines worldwide, they employed fixed doses of statins throughout trials (fire-and-forget approach). In the real clinical setting, however, statin doses are titrated to achieve target low-density lipoprotein cholesterol (LDL-C) levels (treat-to-target approach). The major objective was to investigate whether intensive lipid-lowering therapy using the treat-to-target approach yielded greater regression of aortic plaques. Methods We therefore performed a prospective, randomized trial comparing the effects of standard (achieve LDL-C levels recommended by the Japanese guidelines) and intensive (achieve 30% lower LDL-C levels than standard) rosuvastatin therapy for 1 year in 60 hypercholesterolemic patients with a primary endpoint of aortic atherosclerotic plaques evaluated by non-invasive magnetic resonance imaging (MRI). Results Average doses were 2.9 ± 3.1 and 6.5 ± 5.1 mg/day for standard (n = 29) and intensive therapy group (n = 31), respectively. Although both therapies significantly reduced LDL-C and high-sensitivity C-reactive protein (hsCRP) levels, LDL-C reduction was significantly greater in the intensive group (−46 vs. −34%). MRI study showed that thoracic aortic plaques were significantly regressed in both groups, with greater regression of thoracic plaque in the intensive group (−9.1 vs. −3.2%, p = 0.01). Multivariate analyses revealed that thoracic plaque regression was significantly correlated with hsCRP reduction, but not with changes in serum lipids, endothelial function, or doses of rosuvastatin. Conclusion Intensive statin therapy with titration targeting lower LDL-C levels resulted in greater thoracic aortic plaque regression compared to standard therapy, which was correlated with hsCRP reduction, suggesting that intensive statin therapy could provide better clinical outcomes.
    Atherosclerosis 01/2014; 232(1):31–39. DOI:10.1016/j.atherosclerosis.2013.10.007 · 3.97 Impact Factor
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    ABSTRACT: We estimated the stiffness parameter β (β value), which is useful in the assessment of premature atherosclerosis, among patients with different subtypes of cerebral infarction (CI; eg, small-vessel occlusion, large-artery atherosclerosis, cardioembolism, and other determined and undetermined etiologies) to determine the clinical utility of the β value in classification of stroke patients into CI subtypes. Carotid ultrasonography (ALOKA ProSound SSD-alpha10) was performed in 31 CI patients and 38 control subjects, and the β value of the bilateral common carotid artery at 2.0 cm proximal to the bifurcation was measured using the echo-tracking method. The relationship between β value and age was examined, and the β value was compared among the different CI subtypes. Positive β value correlated with age in control subjects (R = .69, P < .001) but not in CI patients (R = -.01, P = .996). There was no significant difference in the β value when comparing control patients and patients with cardioembolic stroke (P = .106), but the β value were lower in patients with cardioembolic stroke than in patients with noncardioembolic stroke (eg, small-vessel occlusion, large-artery atherosclerosis, and others, P = .009). The β value was lower in patients with cardioembolic stroke than in patients with noncardioembolic stroke. The β value may be useful for estimating the risk of different stroke subtypes.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 01/2014; 23(6). DOI:10.1016/j.jstrokecerebrovasdis.2013.11.015 · 1.99 Impact Factor
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    ABSTRACT: A 64-year-old man had transverse myelopathy that rapidly progressed without pain over the course of 1 day. The cerebrospinal fluid interleukin-6 (CSF IL-6) level was extremely high (1,120 pg/dl). Spinal cord magnetic resonance imaging (MRI) showed a longitudinal extensive lesion extending from Th8 to the conus medullaris. Despite treatment with steroids and cyclophosphamide, the symptoms worsened, and the range of sensory disturbance spread. MRI showed that the lesion expanded to Th3 over the course of 2 months. Neuro-Behçet disease (NBD) was diagnosed on basis of the high CSF IL-6 level and HLA-B51 positivity, and treatment with infliximab was begun. The sensory disturbance improved slightly, and the CSF IL-6 level fell to the normal range (7.0 pg/ml). It is important to include NBD, which rarely presents with extensive spinal cord lesion, in the differential diagnosis when patients present with acute transverse myelopathy without pain.
    01/2014; 54(1):16-21. DOI:10.5692/clinicalneurol.54.16
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    ABSTRACT: A 76-year-old woman was admitted to our hospital because of convulsions that developed after a 1-month history of progressive right-leg palsy. MRI showed thickening of the meninges with gadolinium enhancement in the left parietal lobe and it revealed pia-subarachnoid space pattern. A lumbar puncture was performed, and cerebrospinal fluid analysis revealed no abnormality. Her serum adenosine deaminase level was elevated (28.7 IU/l). The results of serum cultures were normal. To differentially diagnose collagen disease, infection, malignancy, and inflammation of uncommon causes, we conducted brain and meningeal biopsies on the 15th hospital day. Histopathological examination of the brain tissue showed mainly necrosis and inflammation. There was severe pachymeningeal thickening without necrosis. Although it was difficult to reach a definitive diagnosis, a tissue sample taken from under the leptomeninges tested positive for mycobacterium on Ziehl-Neelsen staining. The results of polymerase chain reaction for mycobacterium were negative in the meningeal tissue. The patient received anti-tuberculous drugs, anti-nontuberculous mycobacteriosis drugs, and corticosteroids to treat Mycobacterium tuberculosis and nontuberculous mycobacterium. After starting treatment, the findings on magnetic resonance imaging improved dramatically, and no convulsions occurred during hospitalization. She was discharged on the 153rd hospital day without any neurological deficit. Because previous studies have reported that isolated mycobacterium meningitis is a diagnostically challenging condition, brain and meningeal biopsies should be considered in patients with gadolinium enhancement in the meninges.
    01/2014; 54(2):140-5. DOI:10.5692/clinicalneurol.54.140
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    ABSTRACT: Precise associations between clinical characteristics of transient ischemic attack (TIA) patients and diffusion-weighted imaging (DWI) positivity are still controversial. Thus, the purposes of this were to investigate the clinical characteristics associated with DWI positivity in patients with TIA and to develop a risk score for the prediction of DWI positivity in TIA. Between April 2008 and June 2011, we retrospectively enrolled consecutive patients, who were admitted to our hospital with TIA and underwent DWI within 24 hours of admission. Patients were divided into a DWI-positive or DWI-negative group. The clinical characteristics of the 2 groups were compared, and a DWI positivity score was determined for each patient. We calculated the DWI positivity score by assigning a point value of 1 to the following factors: blood urea nitrogen to serum creatinine (BUN/Cr) ratio greater than 17.5, glucose greater than 161 mg/dL, and brain natriuretic peptide (BNP) greater than 55.4 pg/dL. Values below these cutoffs were given a value of 0, and the 3 point values were summed to obtain the final DWI positivity score (from 0 to 3). A total of 41 patients (median age = 62 years; 8 women) were enrolled in this study. There were 14 (35%) patients with DWI positivity. The median of the BUN/Cr ratio, blood glucose, and BNP were significantly higher in the DWI-positive than that in the DWI-negative group. As the DWI positivity score increased, there was an increased rate of DWI positivity. Our data indicate that seminal scores that included BUN/Cr ratio, glucose, and BNP contributed to DWI positivity in TIA patients.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 10/2013; 23(5). DOI:10.1016/j.jstrokecerebrovasdis.2013.09.002 · 1.99 Impact Factor
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    ABSTRACT: Background: It is unknown whether the clinical features and outcomes of intracerebral hemorrhage (ICH) patients who undergo maintenance hemodialysis (HD) at the time of ICH are similar to those of general ICH patients. Methods: We retrospectively examined the medical records of ICH patients admitted to the Stroke Center of Kawasaki Medical School Hospital within 7 days of ICH onset between April 2004 and June 2011. Patients were classed as HD or non-HD, and clinical characteristics were compared between the two groups. ICH volume was measured on admission CT and follow-up CT scan ( death within 14 days of ICH onset. The factors associated with early death were determined using multivariate logistic regression analysis. Results: Five hundred and seven patients (320 males; 69.0 years old, interquartile range 59.0-79.0) were enrolled in the study. Thirty-six (7.2%) were receiving maintenance HD at the time of ICH and formed the HD group, and the remaining 471 patients formed the non-HD group. Use of antithrombotic agents prior to ICH was more common in the HD group than in the non-HD group (41.7 vs. 21.9%; p = 0.012). Brainstem (30.6 vs. 11.3%; p = 0.003) and lobar (19.4 vs. 6.6%; p = 0.013) hematoma locations were more common in the HD group than in the non-HD group. Enlargement of ICH volume was more common in the HD group than in the non-HD group (25.8 vs. 10.2%; p = 0.015). Early death was more common in the HD group than in the non-HD group (33.3 vs. 9.3%; p 20 [odds ratio (OR) 27.40, 95% confidence interval (CI) 9.69-77.44; p 30 ml (OR 9.53, 95% CI 3.82-23.77; p 150 mg/dl (OR 2.51, 95% CI 1.01-6.26; p = 0.047) were independent factors associated with early death. Conclusion: Maintenance HD is independently associated with early death in ICH patients.
    Cerebrovascular Diseases 07/2013; 36(1):47-54. DOI:10.1159/000351504 · 3.70 Impact Factor

Publication Stats

1k Citations
440.45 Total Impact Points

Institutions

  • 2013–2015
    • The Jikei University School of Medicine
      • Division of Neurology
      Edo, Tōkyō, Japan
  • 2005–2013
    • Kawasaki Medical University
      • • Department of Stroke Medicine
      • • Department of Neurology
      Kurasiki, Okayama, Japan
  • 2006–2010
    • Kawasaki Saiwai Hospital
      Kawasaki, Fukuoka, Japan
    • Yokohama Brain and Stroke Center
      Yokohama, Kanagawa, Japan
  • 2004
    • University of Houston
      Houston, Texas, United States