Naoyuki Harada

Toho University, Edo, Tōkyō, Japan

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Publications (9)2.37 Total impact

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    ABSTRACT: Basal encephalocele is rare in adults. Congenital and acquired cases have been reported with regard to the developmental mechanism, and the pathology has not been elucidated in detail. We encountered an adult with basal encephalocele strongly suggesting congenital development because of the presence of minor anomalies: strabismus and ocular hypertelorism. The disease manifested as persistent spontaneous cerebrospinal fluid rhinorrhea and repeated meningitis in a 66-year-old Japanese man. On computed tomography, brain tissue protruded through a part of the ethmoid bone of his right anterior skull base, and it was diagnosed as transethmoidal-type basal encephalocele. Regarding his facial form, the distance between his bilateral eyeballs was large compared to his facial width, and his canthal index (defined as inner to outer inter canthal ratio x 100) was calculated as 38.5, based on which it was judged as ocular hypertelorism. In addition, his right eyeball showed strabismus. A right frontotemporal craniotomy was performed for spontaneous cerebrospinal fluid rhinorrhea, and the defective dura mater region was patched with temporal fascia. Mild minor anomalies that require no treatment are overlooked in adults, but the presence of several anomalies increases the possibility of congenital disease. Therefore, it may be necessary to examine minor anomalies in cases of adult basal encephalocele when considering the possibility that the disease may be congenital.
    Journal of Medical Case Reports 01/2014; 8(1):24.
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    ABSTRACT: The trans-sylvian approach is one of the most frequently employed neurosurgical procedures, but it is difficult for medical students to understand the approach stereoscopically. A three-dimensional model equipped with an arachnoid membrane and sylvian vein was developed which can be repeatedly used to simulate surgery for the education of medical students and residents in the trans-sylvian approach. The model was prepared using existing models of the skull bone, brain, and cerebral artery. Polyvinylidene chloride film, commonly used as plastic wrap for food, was adopted for the arachnoid membrane, and wetted water-insoluble tissue paper for the arachnoid trabeculae. The sylvian vein was prepared by ligating woolen yarn with cotton lace thread at several sites. Students and residents performed the trans-sylvian approach under a microscope, and answered a questionnaire survey. Using this model, simulation of division of the arachnoid membrane and arachnoid trabeculae, and dissection of the sylvian vein was possible. In the questionnaire, the subjects answered 8 questions concerning understanding of the stereoscopic anatomy of the sylvian fissure, usefulness of the simulation, and interest in neurosurgical operation using the following ratings: yes, very much; yes; somewhat; not very much; or not at all. All items rated as 'yes, very much' and 'yes' accounted for more than 70% of answers. This model was useful for medical students to learn the trans-sylvian approach. In addition, repeated practice is possible using cheap materials, which is advantageous for an educational model.
    Neurologia medico-chirurgica 01/2011; 51(8):567-71. · 0.49 Impact Factor
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    ABSTRACT: Punch-drunk syndrome (PDS) refers to a pathological condition in which higher brain dysfunction occurs in a delayed fashion in boxers who have suffered repeated blows to the head. However, the underlying mechanisms remain unknown. This study attempted to elucidate the mechanism of higher brain dysfunction observed following skull vibration in two experiments involving a rat model of PDS. Experiment 1 evaluated the effects of edaravone on histological changes in the rat brain tissue after skull vibration (frequency 20 Hz, amplitude 4 mm, duration 60 minutes). The amount of free radicals formed in response to skull vibration was very small, and edaravone administration reduced the number of glial fibrillary acidic protein and advanced glycation end product-positive cells. Experiment 2 examined the time course of change in learning ability following skull vibration in Tokai High Avoider rats. The learning ability of individual rats was evaluated by the Sidman-type electric shock avoidance test 5 days after the last session of skull vibration or final anesthesia and once a month for 9 consecutive months. Delayed learning disability was not observed in rats administered edaravone immediately after skull vibration. These results suggest that free radical-induced astrocyte activation and subsequent glial scar formation contribute to the occurrence of delayed learning disabilities. Edaravone administration after skull vibration suppressed glial scar formation, thereby inhibiting the occurrence of delayed learning disabilities.
    Neurologia medico-chirurgica 01/2011; 51(1):1-7. · 0.49 Impact Factor
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    ABSTRACT: To estimate the usefulness of early dynamic 201Tl single photon emission computed tomography (SPECT) studies in distinguishing the histological malignancy of brain tumours. Dynamic 201Tl SPECT was performed for 3 min per scan for 15 min immediately after the administration of 201TlCl in 110 patients with brain tumours (111 lesions). The data obtained each 3 min were used for dynamic SPECT, and the five sets of data obtained were added to acquire static SPECT data. For static SPECT, the static thallium index (STI) was calculated as the ratio of 201Tl uptake in the tumour to that of the contralateral normal brain. The ratio of the 201Tl uptake for each 3 min was defined as the dynamic thallium index (DTI). The dynamic thallium rate (DTR), as a per cent, was calculated as DTR=(DTI for every 3 min)/STI H 100. The five values were approximated as a linear function and the slope (%/min) was calculated. In static SPECT, there was no significant difference between the STI of malignant tumours (glioblastoma and anaplastic astrocytoma) and that of benign tumours (low-grade glioma, meningioma, pituitary adenoma, neurinoma and haemangioblastoma) (3.7+/-1.5, 5.0+/-3.5, respectively). On dynamic SPECT, DTI increased markedly over 15 min for malignant tumours. In contrast, the DTI of benign tumours increased slightly, steadily or decreased. The slope of the linear functions calculated from the DTRs was much higher in the malignant tumour group than in the benign tumour group (P<0.001). We suggest that the performance of 201Tl dynamic SPECT for 15 min is useful for distinguishing malignant brain tumours from benign brain tumours and reduces the examination stress of patients.
    Nuclear Medicine Communications 02/2006; 27(2):143-9. · 1.38 Impact Factor
  • CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004; 01/2004
  • CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004; 01/2004
  • CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004; 01/2004
  • CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004; 01/2004
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    ABSTRACT: After radiochemotherapy for a post-operative glioblastoma multiforme (GB), the majority of patients return at a later date with a recurrent. To assess whether 201TlCl uptake can be used as a prognostic indicator in patients with GB, we measured the ratio of 201TlCl uptake in tumor to 201TlCl uptake in normal brain (TL index) in 10 patients at the end of radiochemotherapy and followed all the patients until they returned with a recurrent. The TL indices at the end of radiochemotherapy indicated 1.36 to 6.82 (mean +/- SD; 3.59 +/- 1.84), and the terms of tumor recurrent were 3-12 months (5.55 +/- 3.10 month). There was a significant negative correlation between the TL indices and the terms of tumor recurrent (y = -1.28x + 10.14, r = 0.760, p < 0.01). Especially, three cases indicated less than 2.0 did not returned with a recurrent in 8 months and 7 cases more than 2.0 returned with a recurrent in 5 months. This study resulted that 201TlCl SPECT was clinically useful to predict the period of recurrent for GB.
    Kaku igaku. The Japanese journal of nuclear medicine 11/2002; 39(4):519-25.