Emiko Adachi-Usami

Changes of macular and RNFL thicknesses measured by Stratus OCT in patients with early stage diabetes.

PurposeTo examine the early differences in the thicknesses of the macula and retinal nerve fibre layer (RNFL) by Stratus optical coherence tomography in patients with diabetes mellitus.MethodsThirty-one normal participants without any optic nerve and retinal diseases (control), 45 diabetic patients without diabetic retinopathy (NDR), and 24 diabetic patients with preproliferative diabetic retinopathy (PPDR), who did not have clinically significant macular oedema, were used for the macular thickness measurements. Thirty control participants, 45 patients classified as NDR, and 22 patients classified as PPDR were used for the RNFL thickness measurements.ResultsIn patients with NDR, macula was significantly thinner than that of control eyes. In patients with PPDR, the mean RNFL thickness was significantly thinner but the macula was thicker than that of control eyes. In women with NDR, the macula was significantly thinner than that of men with NDR and that of normal women. In men with PPDR, the RNFL thickness was significantly thinner than that of the control eyes.ConclusionsAt the early stage of diabetic retinopathy, the maculas and RNFL thicknesses are altered. The macular and RNFL thicknesses are different in men and women.

Role of Schwann cells in retinal ganglion cell axon regeneration.

It is a well known fact that the injured PNS can successfully regenerate, on the other hand, the CNS such as retinal ganglion cell (RGC) axons of adult mammals is incapable of regeneration. After injury, RGC axons rapidly degenerate and most cell bodies go through the process of cell death, while glial cells at the site of injury undergo a series of responses which underlie the so-called glial scar formation. However, it has become apparent that RGCs do have an intrinsic capacity to regenerate which can be elicited by experimental replacement of the inhibitory glial environment with a permissive peripheral nerve milieu. Schwann cells are a major component of the PNS and play a role in regeneration, by producing various kinds of functional substances such as diffusible neurotrophic factors, extracellular matrix and cell adhesion molecules. RGC regeneration can be induced by cooperation of these substances. The contact of RGC axons to Schwann cells based upon the structural and molecular linkages seems to be indispensable for the stable and successful regeneration. In addition to cell adhesion molecules such as NCAM and L1, data from our laboratory show that Schwann cells utilize short focal tight junctions to provide morphological stabilization of the contact with the elongating axon, as well as a small scale of gap junctions to facilitate traffic of substances between them. Moreover, our results show that modifications of functional properties in neighboring glial cells of optic nerve are induced by transplantation of Schwann cells. Astrocytes usually considered to form a glial scar guide the regenerating axons in cooperation with Schwann cells. A decrease of the oligodendrocyte marker O4 and migration of ED-1 positive macrophages is observed within the optic nerve stump. Accordingly, RGC regeneration is not a simple phenomenon of axonal elongation on the Schwann cell membrane, but is based on direct and dynamic communication between the axon and the Schwann cell, and is also accompanied by changes and responses among the glial cell populations, which may be partly associated with the mechanisms of optic nerve regeneration.

Haemophilus influenzae has a GM1 ganglioside-like structure and elicits Guillain–Barré syndrome

Article abstract The authors report a patient with an axonal Guillain–Barré syndrome (acute motor axonal neuropathy) associated with anti-GM1 antibody after Haemophilus influenzae infection. The result of ELISA inhibition studies and cytochemical staining with cholera toxin suggest the presence of a GM1-like structure on the surface of H. influenzae isolated from the patient. A particular strain of H. influenzae may have a GM1-like structure and may elicit an axonal Guillain–Barré syndrome.

Outcome of Traumatic Optic Neuropathy. Comparison Between Surgical and Nonsurgical Treatment

Summary 34 patients with indirect traumatic optic neuropathy were studied to identify factors affecting outcome and surgical indications. 12 cases (13 eyes = group A) underwent surgery and 24 patients (24 eyes = group B) were managed without surgery. Age, optic canal fracture, visual acuity before treatment (initial visual acuity) and days until surgery (only group A) were employed as variables. Visual acuity improved significantly more in patients with initial visual acuity, hand movement (HM) or better than in those with initial visual acuity for light perception (LP) only or worse. When initial visual acuity was HM or better, vision improved significantly more in patients with surgery than in those without surgery (p=0.0003) by Mann-Whitney U test). Days until surgery were correlated with visual improvement in patients with visual acuity HM or better. Age and optic canal fracture did not affect visual improvement or influence the decision for or against surgery.

Seventeen Cases of Central Serous Chorioretinopathy Associated with Systemic Corticosteroid Therapy

Purpose: To determine the relationship between the clinical characteristics of patients with central serous chorioretinopathy (CSC) and systemic corticosteroid therapy. Methods: The medical records of 17 cases of CSC that developed during systemic corticosteroid treatment from 1987 to 1999 at Chiba University Hospital were reviewed. The relationship of CSC to the age, gender, laterality, and disease requiring the corticosteroid treatment, and the dose and duration of corticosteroid therapy were examined. Results: There were 6 men and 11 women, and 2 of these developed bilateral and 15 developed unilateral CSC. The duration from the beginning of corticosteroid treatment to the onset of CSC ranged from 3 days to 23 years; 9 patients developed CSC within 1 year after the beginning of the corticosteroid medication and 6 patients after more than 8 years. The amount of corticosteroid medication at the onset of CSC ranged from 5 to 1,000 mg/day equivalent prednisolone units. There was a significant correlation between age at the onset of CSC and the daily dosage of corticosteroid. Conclusion: Even small amounts of daily corticosteroids (5–10 mg/day) can cause CSC, especially in elderly patients. These findings indicate that we need to monitor patients undergoing corticosteroid treatment carefully.

Optic nerve regeneration within artificial Schwann cell graft in the adult rat.

We investigate whether an artificial graft made by cultured Schwann cell, extracellular matrix (ECM) and trophic factors can provide the environment for the regeneration of retinal ganglion cell (RGC) axons in adult rats. Six kinds of artificial grafts were used: ECM (control); ECM and Schwann cells; ECM, Schwann cells and either nerve growth factor, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4); ECM, Schwann cells, BDNF and NT-4, combined with intravitreal injection of BDNF. The grafts were transplanted onto the transected optic nerve. RGC regeneration was evaluated by dil retrograde labeling, immunohistochemistry, and electron microscopy at 3 weeks post-operation. The degree of dil labeled RGC was approximately 2% for ECM alone, and 10% for ECM and Schwann cells (p < 0.01). The labeling increased to approximately 20% by administration of neurotrophins. The addition of intravitreous BDNF injection resulted in highest labeling percentage of 30%. Immunohistochemical study showed that axons were association with GAP-43 and cell adhesion molecules. Neurotrophin receptors (Trk-A and Trk-B) were detected in nerve fibers both in the retina and in the graft. Remyelination was seen by electron microscopic observation. These results demonstrate that the regeneration of RGC axons is induced with the use of cultured Schwann cells and ECM as promoting factors for regrowth. The degree of regeneration was significantly increased by neurotrophins in the grafts and in the vitreous.

Functional recovery of retina after sodium iodate injection in mice

ERGs and the azide responses were recorded from mice before and periodically up to 6 weeks after retinal pigment epithelium (RPE) damage by iodate injection to follow the recovery of retinal pigment epithelium and retinal function. At 14 days postinjection, there was a partial recovery of the maximal b-wave amplitude and the azide response but no further recovery was found after 14 days. The retinal sensitivity showed a slow recovery, and at 6 weeks postinjection did not differ from the pre-iodate sensitivity. These findings correlated with histological observations. We concluded that the recovery in ERGs resulted from RPE recovery and the large patchy area of recovered retina functioned normally.

Correlation of Electroretinographic Changes with Visual Prognosis in Central Retinal Artery Occlusion

Recent advances in the treatment of central retinal artery occlusion (CRAO) have resulted in a relatively good prognosis, but few studies have been reported. In the present study, electroretinography (ERG) was used to evaluate visual function recovery in 15 cases of CRAO. All patients were treated with ocular massage, intravenous urokinase and hyperbaric oxygenation. Of 15 cases, 8 had improved vision after treatment. A single flash ERG of 40 J from a xenon lamp was recorded before and during treatment. For ERG evaluation, the a- and b-wave amplitudes and the b/a wave amplitude ratio were analyzed. As control, the nonaffected eye of each patient was used. Before treatment, no significant difference was found in the a-wave amplitude between the two eyes, while a significant attenuation was found in the b-wave of the affected eye (p < 0.01). The b/a ratio was 0.73 +/- 0.04 (mean +/- SE) in the affected eye group and 1.08 +/- 0.03 in the nonaffected eye group. It was significantly higher (p < 0.01) in eyes with improved visual acuity (0.83 +/- 0.03) than in those with unimproved visual acuity (0.62 +/- 0.05). The b-wave amplitude increased in accordance with visual improvement. We could thus demonstrate the temporal changes of ERG before and after treatment and show their correlation with the visual prognosis in patients with CRAO.

Protective Effect of Docosahexaenoic Acid against Retinal Ischemic Injury: An Electroretinographic Study

Purpose: To determine whether docosahexaenoic acid (DHA) can reduce the retinal damage induced by transient retinal ischemia. Methods: Retinal ischemia was induced by increasing intraocular pressure (IOP). Retinal circulation was restored by lowering IOP. An intraperitoneal injection of 1,000 mg/kg of DHA-ester (DHA-E) was given 5 h before the ischemia. Electroretinograms were recorded just before the ischemia and at 60-min intervals up to 4 h after circulation was restored. Results: The ratio of the amplitudes after the ischemia to that just before ischemia was significantly higher in eyes administered DHA-E than in controls at each time point (p < 0.01). Conclusion: DHA-E is effective in protecting the retina against transient retinal ischemia.

Criteria for early detection of temporal hemianopia in asymptomatic pituitary tumor

Purpose To determine new criteria for early detection of temporal hemianopia in patients with asymptomatic pituitary tumor.Methods Fifteen patients without visual symptoms had pituitary tumor and subtle defects or normal visual fields by Goldmann perimetry. Twelve patients with visual symptoms had pituitary adenoma and visual field defects detected by Goldmann perimetry. All were examined by automated perimetry. The relationship between the tumor and the optic chiasm was graded by magnetic resonance imaging (MRI) on a scale of 0–4. Grade number increased with extent of compression. Temporal hemianopia observed by automated perimetry was estimated from normal data (52 normal fields). Vertical step was determined from the number of adjacent pairs along the midline; sensitivity was lower in the temporal field than in the nasal field. Temporal depression was calculated by the quadrant sum of sensitivity.Results All patients with symptomatic pituitary adenoma had vertical step and temporal depression in the upper field. Nine of 15 patients without visual symptoms had vertical step or temporal depression. Of nine patients with temporal hemianopia, two of four patients had grade 1 compression, three of five had grade 2, and four of four had grade 3.Conclusion New criteria by automated perimetry could detect temporal hemianopia in patients with asymptomatic pituitary tumor.