Satoshi Ueki

Clinicopathological features in anterior visual pathway in neuromyelitis optica.

Neuromyelitis optica spectrum disorder (NMOsd) is an autoimmune disorder of the central nervous system characterized by aquaporin‐4 (AQP4) autoantibodies. The aim of this study was to elucidate the characteristics of involvement of the anterior visual pathway (AVP) and neurodegeneration via glia–neuron interaction in NMOsd.

Retinal nerve fiber layer thickness in recovered and persistent amblyopia

Purpose: To investigate, using optical coherence tomography (OCT), whether retinal nerve fiber layer thickness (RNFLT) is affected in amblyopic eyes. Methods: Using OCT (Stratus OCT™ [Carl Zeiss, Dublin, CA]), the RNFLT was measured in 26 patients with persistent unilateral amblyopia and in 25 patients with recovered unilateral amblyopia. The RNFLT was compared between the affected and fellow eyes in patients with persistent amblyopia and in those with recovered amblyopia, and between the amblyopic eyes of patients with persistent amblyopia and the previously amblyopic eyes of patients with recovered amblyopia. Results: In patients with persistent amblyopia and in those with recovered amblyopia, the affected eyes were significantly more hyperopic than the fellow eyes. The average (±standard deviation) RNFLT measured 105.5 ± 14.0 μm for the persistently amblyopic eyes; this value did not significantly differ from that of the fellow eyes (105.2 ± 13.0 μm) or the previously amblyopic eyes of recovered amblyopia (107.1 ± 11.7 μm). Also, logistic regression analysis adjusting for refraction showed no significant difference in the RNFLT between the persistently amblyopic eyes and the previously amblyopic eyes. Conclusions: Our results indicate that there is no significant change in the RNFLT in amblyopic eyes.

Mizuo phenomenon observed by scanning laser ophthalmoscopy in a patient with Oguchi disease

PURPOSE To elucidate the origin of the abnormal fundus reflex in Oguchi disease. METHODS The ocular fundus of a 63-year-old woman who showed a homozygous arrestin 1147delA mutation was observed by scanning laser ophthalmoscopy with the use of an argon blue laser (wavelength, 488 nm), a helium-neon laser (633 nm), and an infrared laser (780 nm). RESULTS Diffuse, fine, white particles, which do not exist in normal subjects, were clearly demonstrated only with the helium-neon laser. After 4-hour dark adaptation, the abnormal particles disappeared, but then they reappeared gradually during 30 minutes of light adaptation, in accordance with the golden metallic reflex. CONCLUSION The white particles found by helium-neon laser could be the origin of the abnormal fundus reflex in Oguchi disease.

Preoperative depiction of cavernous sinus invasion by pituitary macroadenoma using three-dimensional anisotropy contrast periodically rotated overlapping parallel lines with enhanced reconstruction imaging on a 3-tesla system.

OBJECTIVES Three-dimensional anisotropy contrast (3DAC) magnetic resonance (MR) imaging provides clear depiction of neuronal fibers. The aim of this study was to identify intracavernous cranial nerves in patients with pituitary macro-adenoma and in healthy volunteers by using 3DAC MR imaging on a 3-tesla system and to preoperatively predict cavernous sinus invasion by pituitary macroadenoma. METHODS Thirty-three patients (cavernous sinuses in 66 sides) with pituitary macroadenomas and 25 healthy volunteers (50 sides) participated in this study. Coronal 3DAC MR images constructed from diffusion weighted images, acquired with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) sequences, and T2-weighted reverse images were obtained at the same anatomical locations using a 3-tesla MR imaging system. Attempts were made to identify the cranial nerves. RESULTS The oculomotor and ophthalmic/maxillary nerves were preoperatively identified in all sides (66 sides in patients and 50 sides in healthy volunteers) on 3DAC MR images. In the 33 patients, cavernous sinus invasion was revealed in 10 (12 [18.2%] of 66 sides) by intraoperative endoscopic observation. Coronal 3DAC MR images revealed that the oculomotor nerves were half surrounded with adenoma in all 12 of these sides, and the ophthalmic/maxillary nerves were half encapsulated with tumor (sensitivity/specificity: 100%/100% and 83%/100%, respectively). CONCLUSIONS Preoperative evaluation of pituitary macroadenomas using 3DAC PROPELLER MR imaging on a 3-tesla system is likely to be a powerful noninvasive method of detecting cavernous sinus invasion, which can potentially dominate the therapeutic strategy for these lesions.

ERG rod a-wave in Oguchi disease.

We analyzed the change in the ERG rod a-wave waveform during the course of dark adaptation in two patients with Oguchi disease. Two Japanese patients showed a homozygous arrestin 1147delA mutation. Scotopic flash ERGs were recorded after different periods of dark adaptation. ERG rod a-waves were obtained after subtraction of the cone ERG contribution. The rod a-waves were fitted with a model of the rod receptor signal. The parameters, Rm(p3) (maximum a-wave amplitude) and S (sensitivity) were calculated. Longer periods in the dark produced larger rod a-wave but only to the first flash presented. The amplitude of the response to subsequent flashes was essentially independent of the period of dark adaptation. Rm(p3) increased with advance of dark adaptation. However, S was nearly constant. Our results suggest that the cause of delayed dark adaptation is not to be sought in the activation of phototransduction process or the regeneration of rhodopsin per se but rather in the deactivation process of the phototransduction cascade.

Optic disc measurements using the Heidelberg Retina Tomograph in amblyopia.

Purpose: To investigate the characteristics of optic disc parameters in amblyopic eyes in which retinal involvement is uncertain. Methods: A total of 44 patients with a history of unilateral amblyopia (27 patients with persistent amblyopia and 17 patients with resolved amblyopia) were examined using the Heidelberg Retina Tomograph (HRT) II. Parameters examined included disc area, cup area, cup volume, rim area, rim volume, cup-to-disc area ratio, and mean retinal nerve fiber layer thickness. Results: In patients with persistent amblyopia, the amblyopic eyes were significantly more hyperopic than the fellow eyes. In the HRT parameters, there were no significant differences between the amblyopic and fellow eyes. In addition, after adjusting for refraction, the presence of strabismus, and the disc area, there was no significant difference in any HRT parameter between the amblyopic eyes of patients with persistent amblyopia and the previously amblyopic eyes of patients with resolved amblyopia. Conclusions: We did not find any strong evidence for the deformity of the optic disc of amblyopic eyes.

Ocular fundus images by scanning laser ophthalmoscopy in a patient with enhanced S-cone syndrome.

Purpose: To present ocular fundus images in a patient with enhanced S-cone syndrome by scanning laser ophthalmoscopy. A 34-year-old Japanese woman whose parents were consanguineous showed mismatched electroretinographic responses to photopically balanced single-flash stimuli, with a larger signal to blue light than to red light. The central macula lacked a foveal reflex, and the surface was dull. Yellowish flecks and retinal pigment epithelium atrophy were evident in a ring at and around the vascular arcades. Faint black pigmentation was deposited in the mid peripheral retina. Methods: The ocular fundus of the patient was observed by scanning laser ophthalmoscopy with the use of an argon blue laser (wavelength, 488 nm), a helium-neon laser (633 nm), and an infrared laser (780 nm). Results: The argon blue laser showed numerous black spots of pigment, which were observed as faint pigmentation by conventional ophthalmoscopy. The spots were more enhanced with the argon blue laser than with the helium-neon laser. The white spots, which corresponded to the yellowish flecks in a ring at and around the vascular arcades, were more enhanced with the helium-neon laser than with the argon blue or infrared laser. Hypopigmentation of the retinal pigment epithelium was best shown with the infrared laser. Conclusion: An abnormality of the retinal structure in enhanced S-cone syndrome may exist in the inner and outer retinal levels, in at least some patients.

Secondary glaucoma associated with bilateral complete ring cysts of the ciliary body.

Purpose:To report a case of acute glaucoma due to complete ring cyst of the ciliary body. Patients and Methods:A 33-year-old woman experienced blurred vision in her left eye. Intraocular pressure of the left eye was elevated accompanied with a very shallow anterior chamber. Anterior segment-optical coherence tomography and ultrasound biomicroscopy detected ring-shaped ciliary masses in the both eyes. Myopic change and contact between the ciliary mass and lens in the left eye suggested the presence of aqueous misdirection resulting in forward displacement of the lens-iris diaphragm. Because elevated intraocular pressure was refractory to conservative management, the left eye underwent clear lens aspiration and implantation of intraocular lens. Results:Although the anterior chamber became deep in the left eye initially after lens extraction in conjunction with core vitrectomy, possible aqueous misdirection recurred. Second vitrectomy in the left eye together with posterior and anterior capsulotomies, to establish humoral communication between the anterior and posterior chambers, deepened the anterior chamber and lowered the intraocular pressure. The anterior chamber in the fellow right eye remained deep a year after the episode. Conclusions:This is the first reported case of bilateral ring cysts of the ciliary body. The manifestation caused secondary glaucoma, which was resolved by lensectomy and vitrectomy.

Maturational decrease of glutamate in the human cerebral cortex from childhood to young adulthood: a 1H-MR spectroscopy study

BackgroundThe aim of the present study was to investigate maturational changes in glutamate (Glu) in the human cerebral cortex from childhood to young adulthood using 3.0-Tesla proton magnetic resonance spectroscopy (1H-MRS), which is capable of quantifying Glu in vivo.MethodsNormal volunteers comprising 11 children (aged 4–13 years) and 11 young adults (aged 18–33 years) participated in the study. Single-voxel point-resolved spectroscopy (PRESS, repetition time/echo time=2,000/80 ms) was performed on the frontal and occipital cortices, and the Glu-to-creatine ratio (Glu/Cr) and N-acetylaspartate-to-creatine ratio (NAA/Cr) were determined.ResultsIn both the frontal and occipital cortices, Glu/Cr was significantly lower during young adulthood relative to that during childhood. NAA/Cr did not differ significantly between the two age groups.ConclusionThis study has provided objective evidence that cerebral cortical Glu/Cr decreases between childhood and young adulthood. The observed decrease in Glu/Cr may reflect the simultaneous occurrence of maturational changes, such as changes in cortical microstructure and the intercellular compartmentation of Glu metabolism.

Magnetic Resonance Imaging of Neurotransmitter-Related Molecules

Molecular imaging implies the method capable of pictorially displaying distribution of target molecules and their relative concentration in space. In clinical medicine, where non-invasiveness is mandatory, diagnostic molecular imaging has been considered virtually identical to positron emission tomography (PET). However, there is another powerful, apparently underutilized molecular imaging, namely, proton magnetic resonance spectroscopic imaging (1H-MRSI). The technique can detect target molecules endogenous in brain in virtue of their own specific resonance frequencies (chemical shift) and can create quantitative images of each molecule. 1H-MRSI is conventionally utilized for imaging relatively easily detectable molecules such as N-acetyl-aspartate or lactate. More recently, however, the method is extended into imaging of more challenging molecules such as glutamate or γ-aminobutyric acid (GABA). In this small review, we summarize basic concept of 1H-MRSI and introduce an advanced technique, i.e. chemical exchange saturation transfer magnetic resonance imaging (CEST MRI), which made realistic glutamate imaging in vivo possible.