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Biomedical subjects

Kenji Ohtsuka

Publications and source records attributed to Kenji Ohtsuka.

At least 19 recordsLinked to original sources
PubMed2005

Glyceraldehyde-derived advanced glycation end-products preferentially induce VEGF expression and reduce GDNF expression in human astrocytes.

The blood-brain barrier (BBB) is a biological unit composed of capillary endothelial cells and astrocytes. Here we examined the effects of various types of advanced glycation end-products (AGEs) on astrocytes and BBB-forming endothelial cells. While no type of AGE we examined changed the permeability of endothelial sheets, glyceraldehyde-derived AGE induced VEGF expression most significantly in astrocytes. The expression of glial cell line-derived neurotrophic factor (GDNF), which reduces the vascular permeability, was decreased in the astrocytes by treatment with glyceraldehyde-derived AGE. These results indicate that glyceraldehyde-derived AGE is the biologically active substance for astrocytes by regulating the VEGF and GDNF expression, which is causally contributing to an increase in the permeability of the BBB.

Astrocytes↗
PubMed2005

Relationship of dissociated optic nerve fiber layer appearance to internal limiting membrane peeling.

PURPOSE: The dissociated optic nerve fiber layer (DONFL) appearance features numerous arcuate striae after vitrectomy for idiopathic epiretinal membrane or macular hole. We studied the relation between the DONFL appearance and internal limiting membrane (ILM) peeling and performed static microperimetry to explore the possible mechanisms underlying the DONFL appearance. DESIGN: Prospective cohort study. PARTICIPANTS: Ninety-five eyes of 88 consecutive patients undergoing vitrectomy for idiopathic macular hole. METHODS: Vitrectomy and gas tamponade were performed with or without ILM peeling. All eyes were examined postoperatively using fundus photography with blue filters. Static microperimetry was performed in 31 eyes with a clearly visible DONFL appearance. MAIN OUTCOME MEASURE: The postoperative incidence of the DONFL appearance on blue-filtered fundus photographs. The secondary outcome measure included the microperimetry threshold value in the arcuate striae and the surrounding normal retina within the papillomacular bundle. RESULTS: On blue-filtered photographs, 46 (62.2%) of 74 eyes with ILM peeling exhibited the DONFL appearance, compared with 0 (0%) of 21 eyes without ILM peeling (P = 0.0002). The area of the DONFL appearance was limited to the area of ILM peeling. There was no difference in the microperimetry threshold value between the arcuate striae and the surrounding normal retina (P = 0.9312). CONCLUSION: The present study indicates that the DONFL appearance might be related to ILM peeling and is not associated with the loss of optic nerve fibers. These results are consistent with the suggestion that the DONFL appearance might be caused by cleavage of the optic nerve fiber bundles due to damage to the Müller cells, which are in close contact with the ILM and act to maintain the close proximity of the nerve fiber bundles.

Aged↗
PubMed2005

A case of posterior ischemic optic neuropathy in a posterior-draining dural cavernous sinus fistula.

A 79-year-old woman presented with sudden unilateral visual loss after an ocular motor disturbance and pulsatile tinnitus. Neuro-ophthalmologic examination showed a presumed right posterior ischemic optic neuropathy (PION), oculosympathetic, and third, sensory fifth, and sixth cranial nerve pareses. Selective angiography of the right internal and external carotid arteries confirmed a posterior-draining dural carotid cavernous sinus fistula (CCF) fed by the right meningohypophyseal trunk and right middle meningeal artery. Angiography also showed an ophthalmic-middle meningeal arterial anastomosis. We postulate that the PION was caused by an arterial steal, because blood was drawn into the fistula and away from the intraorbital optic nerve.

Aged↗
PubMed2005

Acute annular outer retinopathy.

Acute annular outer retinopathy is an uncommon disorder of uncertain aetiology characterized by a unilateral visual field defect with an irregular annular band of grey-white, deep retinal opacification in a peripapillary location. Acute annular outer retinopathy is considered to be a variant of acute zonal occult outer retinopathy. The case is reported of acute annular outer retinopathy with spontaneous good visual recovery and no ophthalmoscopic sequelae.

Acute Disease↗
PubMed2005

Gain of human torsional optokinetic nystagmus depends on horizontal disparity.

PURPOSE: To investigate the effects of horizontal disparity on torsional optokinetic nystagmus (tOKN) in humans. METHODS: Ten healthy human subjects were selected for this experiment. Monocular eye movements were recorded three-dimensionally using dual-search coil methods. Torsional OKN was induced by a rotating random-dot pattern (22 degrees in diameter, constant angular velocity: +/-54 deg/s) projected on the virtual screen of the optical see-through, head-mounted display (HMD). The optical distance of the HMD's virtual screen was 2 m. A red LED that could be fixated through the virtual screen of the HMD was located near the center of the rotating random-dot pattern. Horizontal disparity was induced by changing the distance between the fixated target and the subject systematically (1, 1.5, 2, or 3 m; five subjects) or by the prism (+1.5, +0.5, 0, or -0.5 prism-diopter [PD] in each eye; five subjects) in front of the HMD. RESULTS: The average gain with zero horizontal disparity (0.022 +/- 0.008/0.025 +/- 0.014, fixated target at 2 m/fixated target with the plain glass) was significantly higher than the gain with crossed disparity (0.017 +/- 0.003/0.019 +/- 0.008, target at 3 m/with the prism of -0.5 PD) and uncrossed disparity (0.017 +/- 0.002, target at 1 m/with the prism of +1.5 PD; one-way ANOVA, P <0.05). CONCLUSIONS: The horizontal disparity of optokinetic stimulus affects tOKN. Nonzero horizontal disparity decreases the gain of tOKN.

Adult↗
PubMed2005

An unusual case of congenital convergent convergent strabismus fixus.

BACKGROUND: Convergent strabismus fixus is classified into congenital and acquired types; however, there are only a few detailed case reports of congenital convergent strabismus fixus. Here, we report a rare case of this condition in which the eyeball was shown by imaging diagnosis to be fixed with a hard cord-like material in the orbit. To our knowledge, there have been no previous reports of congenital convergent strabismus fixus caused by an abnormal cord-like material that was clearly identifiable by imaging. CASE REPORT: The patient was a 16 year old female who visited our department for consultation regarding restoration of normal appearance of her strabismus. She had undergone strabismus surgery at the age of 3 years, but a forced duction test was strongly positive in all directions, and the eyeball was not mobile at the time. The initial surgery performed was a tenotomy of the medial rectus muscle and inferior rectus muscle and resection of the lateral rectus muscle of the right eye. The eye position and eye movement remained unchanged after surgery. At this time, MRI of the orbital region was performed, and an abnormal cord-like material connecting the posterior eyeball to the orbital wall was detected in the orbit. The cord-like material was pulling strongly on the posterior eyeball, congenitally fixing the eye position internally. CONCLUSION: We experienced a rare case in which a hard cord-like material in the orbit congenitally fixed the position of the eyeball. On MRI, the intensity of the cord-like material was clearly different from those of the muscle and nerve tissues. Considering the linearity of the cord-like material and the results of a forced duction test, the cord-like material probably consisted of fairly hard tissue, similar to bone.

Adolescent↗
PubMed2004

Diverse NF-kappaB expression in epiretinal membranes after human diabetic retinopathy and proliferative vitreoretinopathy.

PURPOSE: Formation of epiretinal membranes (ERMs) after proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR) results in progressive deterioration of vision, but its pathogenic mechanisms are still unknown. This study was conducted to examine the role of nuclear factor kappa B (NF-kappaB) in the formation of ERMs after PDR and PVR. METHODS: ERM samples were obtained by vitrectomy from 10 patients with PDR (aged 53+/-12 years with 14+/-5 years of diabetes), 20 patients with PVR, and 17 patients with idiopathic ERMs. Ten PVR and 17 idiopathic ERM samples were processed for reverse transcription-polymerase chain reaction (RT-PCR) analysis. In addition, 10 PDR and 10 PVR membranes were processed for immunohistochemical analysis. RESULTS: NF-kappaB mRNA expression levels were significantly higher (10 of 10 versus 9 of 17 subjects in idiopathic ERM, p=0.0119) in PVR subjects. Immunohistochemical analysis showed NF-kappaB protein expression in 8 of the 10 PDR samples as well as all 10 PVR samples, and NF-kappaB positive cells were partially double labeled with glial cell markers. Interestingly, NF-kappaB protein was also overlapped with angiogenic factor interleukin-8 (IL-8) in glial cells as well as vascular endothelial cells. CONCLUSIONS: These results suggest that NF-kappaB is involved in the formation of both glial and vascular endothelial cell components, and that these two cell types might have functional interactions that lead to the enlargement of intraocular proliferative membranes.

Adult↗
PubMed2004

Optical coherence tomographic findings of dissociated optic nerve fiber layer appearance.

PURPOSE: To examine the features of optical coherence tomographic (OCT) findings of dissociated optic nerve fiber layer (DONFL) appearance. DESIGN: Case-control study. METHODS: Twenty-four eyes undergoing vitrectomy for idiopathic epiretinal membrane or macular hole were examined postoperatively using OCT. RESULTS: Thirteen of the 24 eyes exhibited the DONFL appearance. In these 13 eyes, the OCT images indicated dimples in the retinal nerve fiber layer (RNFL) corresponding to each stria. The RNFL thickness (mean +/- SD) at the dimple site was 38.1 +/- 9.3 microm. The depth of each dimple was 28.6 +/- 8.0 microm. The depths of all the dimples were limited to the RNFL thickness. In the other 11 eyes without the DONFL appearance, OCT images showed no distinct dimples. CONCLUSIONS: The DONFL appearance is caused by dimples the depths of which are limited to the RNFL thickness.

Case-Control Studies↗
PubMed2004

High incidence of orbital malignant lymphoma in Japanese patients.

PURPOSE: To review 244 cases of orbital tumors to determine pathologic findings in Japanese patients. DESIGN: Observational case series. METHODS: We studied the pathology and origin of tumors in the orbit in 244 consecutive Japanese patients with orbital tumors at our institution from 1981 through 2002 (age 0 to 90 years, mean, 48.7 years; 114 men, 130 women). RESULTS: The most common tumors were lymphoproliferative diseases (n = 114, 42.5%), including malignant lymphoma (n = 59, 24.1%) and reactive lymphoid hyperplasia (n = 45, 18.4%), pleomorphic adenoma (n = 21, 8.6%), and cavernous hemangioma (n = 18, 7.4%). CONCLUSION: The incidence of lymphoproliferative diseases, especially malignant lymphoma, was very high in Japanese patients.

Adolescent↗
PubMed2004

Convergence eye movements evoked by microstimulation of the rostral superior colliculus in the cat.

Results of our previous studies suggest that the circumscribed area in the rostral superior colliculus (SC) of the cat is involved in the control of accommodation. Accommodation is closely linked with vergence eye movements. In this study, we investigated whether or not vergence eye movements are evoked by microstimulation of the rostral SC in the cat. In addition, we studied the effect of chemical inhibition of the rostral SC on visually guided vergence eye movements. This study was conducted on three cats, weighing 2.5-3.5 kg. The animals were trained to carry out visually guided saccade and convergence tasks. Eye movements were measured using search coils placed on both eyes. We recorded eye movements evoked by microstimulation of the rostral SC in the alert cats. Muscimol was injected into the rostral SC, and the effect of SC inactivation on visually guided vergence eye movements was investigated. Convergence eye movements were evoked by low-current stimulation (< 30 microA) of a circumscribed area in the intermediate layers of the rostral SC on one side. Spontaneous saccades were interrupted by the stimulation of the low-threshold area for evoking convergence. Visually guided convergence eye movements were severely diminished by the injection of muscimol into the low-threshold area for evoking convergence of the SC. The rostral SC is related to the control of vergence eye movements as well as accommodation. The rostral SC may be involved in the functional linkage between accommodation, convergence and visual fixation.

Action Potentials↗
PubMed2004

Nodular scleritis and panuveitis with erythema elevatum diutinum.

PURPOSE: To report a case of nodular scleritis and panuveitis associated with erythema elevatum diutinum, a rare immunocomplex-mediated skin disease. DESIGN: Observational case report. METHODS: A 22-year-old woman who was diagnosed with erythema elevatum diutinum developed nodular scleritis and panuveitis of the right eye. She had experienced peripheral ulcerative keratitis with corneal perforation. RESULTS: All other known causes of nodular scleritis and panuveitis were investigated and ruled out. CONCLUSIONS: Erythema elevatum diutinum should be considered as an underlying systemic disease associated with nodular scleritis and panuveitis as well as peripheral keratitis.

Adult↗
PubMed2004

Superior oblique myokymia caused by vascular compression.

A 49-year-old man had left superior oblique myokymia for eight years. Magnetic resonance images with enhanced spoiled gradient recalled acquisition in the steady state (SPGR) and flow imaging using steady acquisition (FIESTA) disclosed a branch of the superior cerebellar artery lying on the root exit zone of the left trochlear nerve. Posterior fossa craniotomy confirmed the imaging findings. A Teflon pad was placed between the compressing artery and the trochlear nerve. The patient's superior oblique myokymia has completely resolved with a one-year follow-up. Only one such case has been previously reported. This is the first report to display the imaging findings.

Cerebral Arteries↗
PubMed2004

Treatment for A and V strabismus by slanting muscle insertions.

PURPOSE: To evaluate the therapeutic effects of surgically slanting extraocular muscle insertions. RESEARCH DESIGN: Observational case series. METHODS: We performed slanting recession and resection on medial or lateral rectus muscles. We created a slanting surgical reinsertion line with a 3-4 mm difference between upper and lower corners of the muscles, in 31 patients with A or V strabismus (V exotropia in 16 patients; A exotropia in 12; A esotropia in 3). Cases with V exotropia with moderate or marked overaction of inferior oblique muscle were excluded. RESULTS: V exotropia: The average amount of V pattern was 17.9 PD before and 7.6 PD after surgery. Slanting surgery reduced the V pattern in 15 of 16 patients. The mean amount of reduction was 10.3 PD in the V pattern and 29.8 PD in upgaze. A exotropia: The average amount of the A pattern was 26.6 PD before and 6.3 PD after surgery. Slanting surgery reduced the A pattern in 8 of 12 patients. The mean reduction was 20.3 PD in the A pattern and 36.4 PD in downgaze. A esotropia: The average amount of the A pattern was 23 PD before and 8 PD after surgery, reducing the A pattern in 1 of 3 patients. CONCLUSION: The surgical technique of slanting muscle insertions for correction of A and V strabismus is a suitable procedure for reducing or eliminating A and V patterns.

Adolescent↗
PubMed2004

A case of a slipped medial rectus muscle after strabismus surgery.

BACKGROUND: A slipped muscle after strabismus surgery is a well known complication, but only a few cases have been reported in the medical literature. Here, we report a case of a slipped medial rectus muscle that occurred after strabismus surgery for esotropia. CASE REPORT: The patient was a 10 year old male with an acquired esotropia of 20 PD at distance. For treatment, 3.5 mm bilateral medial rectus recessions was performed. There were no complications during the procedure. On postoperative day 8, the eye position was orthotropic in primary position, but a right exotropia was observed in left gaze. The boy was frequently observed rubbing his right eye after surgery. The right exotropia increased to 30 PD 2 months after surgery. Limited adduction of the right eye, a large widening of the lid fissure on adduction, and mild exophthalmos were observed. Based on the above findings, a slipped medial rectus was suspected, and a second surgery, advancement of the right medial rectus muscle was performed 2.5 months after the initial procedure. After this second procedure, the eyes became orthotropic, and the adduction disorder, large widening the lid fissure, and mild exophthalmos resolved. CONCLUSION: The slipped muscle may have been caused by insufficient suture and/or excessive rubbing of the eye by the patient. When divergent strabismus is observed after recession of the medial rectus muscle, a slipped muscle should be considered as a differential diagnosis.

Child↗
PubMed2003

Effect of steroid pulse therapy with and without orbital radiotherapy on Graves' ophthalmopathy.

PURPOSE: To report the effect of high-dose intravenous corticosteroid pulse therapy with and without orbital radiotherapy on Graves' ophthalmopathy. DESIGN: Nonrandomized clinical trial. METHODS: We selected 39 Japanese patients (age range, 22-64 years; mean, 48 years; 31 women, 8 men) who had active Graves' ophthalmopathy among 195 consecutive patients. In the first 20 patients, high-dose intravenous methylprednisolone pulse therapy (1 g per day for 3 successive days, repeated 3 times within 3 weeks) followed by 24-Gy orbital radiotherapy was performed. In the other 19 of the 39 patients, high-dose intravenous methylprednisolone pulse therapy without orbital radiotherapy was performed. Coronal computed tomography (CT) of the orbit and exophthalmometry were performed before the corticosteroid pulse therapy, and 1 and 6 months after the corticosteroid pulse therapy. The maximum coronal section area of the most hypertrophic rectus muscle in each eye was measured based on orbital CT imaging. RESULTS: Clinical findings at study entry were not significantly different between the two groups. No significant difference was found in the maximum coronal section area of the most hypertrophic rectus muscle and the results of exophthalmometry measurements in both groups before the therapy. Extraocular muscle hypertrophy was significantly reduced 1 month and 6 months after the therapy (P < .01) in both groups. However, no beneficial therapeutic effect on proptosis was observed in either group at 1 month and 6 months after the therapy. No significant difference in the therapeutic effect on extraocular muscle hypertrophy and proptosis was found between the two groups. CONCLUSIONS: Orbital irradiation after corticosteroid pulse therapy had no beneficial therapeutic effects on rectus muscle hypertrophy or proptosis of active Graves' ophthalmopathy during the 6-month follow-up period.

Adult↗
PubMed2003

Three-dimensional eye movement analysis of superior oblique myokymia.

PURPOSE: To confirm the idea that sole contraction of the superior oblique muscle causes attacks of superior oblique myokymia (SOM). DESIGN: Observational case report. METHODS: A 43-year-old man presented with episodic monocular oscillatory eye movements. Three-dimensional eye movements were recorded using the magnetic search coil system and analyzed as rotation vector. The attacks of SOM consisted of intorsional, depressive, and abductive fast phases and their exponential decaying slow phases. RESULTS: Average direction of rotation axis for the fast phases while fixating straight ahead was 51.5 +/- 5.4 degrees from depression axis in vertical-torsional plane, 78.7 +/- 4.4 degrees from abduction axis in horizontal-torsional plane, and 76.3 +/- 4.3 degrees from abduction axis in horizontal-vertical plane (+/-SD, n = 50). Time constants of slow phases were less than 0.1 second. CONCLUSIONS: Quantitative three-dimensional analysis of SOM directly confirmed that the fast phases of SOM attacks were induced by the sole contraction of the superior oblique muscle.

Adult↗