M. Usui

Supplementation of CD4+CD25+ regulatory T cells suppresses experimental autoimmune uveoretinitis

Aims: To investigate whether supplementation of natural CD4+CD25+ regulatory T cells ameliorates mouse experimental autoimmune uveoretinitis (EAU) induced by CD4+ T cell-dependent interphotoreceptor retinoid-binding protein (IRBP). Methods: C57BL/6 mice were immunised with human interphotoreceptor retinoid-binding protein peptide 1–20 (IRBP1–20), and IRBP1–20-sensitised T cells were obtained. CD4+CD25+ T cells derived from naive mice were cocultured with IRBP1–20-sensitised T cells, and their proliferation responses and cytokine production were measured. In addition, CD4+CD25+ T cells were transferred intravenously into mice 7 or 15 days after immunisation with IRBP1–20, and the severity of EAU and T cell proliferation responses were evaluated. Results: CD4+CD25+ regulatory T cells effectively inhibited both the proliferation of, and interleukin (IL)2, IL5 and interferon (IFN)γ production by, IRBP1–20-sensitised T cells. Adoptive transfer of CD4+CD25+ regulatory T cells to IRBP1–20-immunised mice conferred considerable protection from EAU development and inhibition of T cell proliferation responses to IRBP1–20. Conclusion: These findings show that natural CD4+CD25+ regulatory T cells possess the ability to inhibit activation of IRBP-reactive T cells that have been already sensitised in vivo, and adoptive transfer of these cells ameliorates EAU even in the effector phase. Supplementation of natural CD4+CD25+ regulatory T cells may have therapeutic potential for effective treatment of uveitis.

A new method for assessing motion-in-depth perception in strabismic patients

Aim: In strabismus clinics, stereoscopic depth perception is usually examined using static stimuli, but these stimuli do not necessarily allow assessment of the ability to perceive motion in depth. We assessed the ability to perceive motion-in-depth perception using a novel stereo motion test that we developed and compared with that to perceive static depth perception using a conventional stereo test in strasbismic patients. Methods: To investigate motion-in-depth perception in patients with strabismus, we developed a stereo motion test using four types of computer-generated dynamic visual stimuli. Three of them are random dot stereograms of two parallel planes moving in depth. The patient is asked to indicate the planes’ direction of rotation in depth (in the first and second types) or the presence/absence of motion-in-depth signal (in the third type). The fourth type of stimulus was a random dot stereogram of a rotating cylinder. The upper and lower parts of the cylinder rotate in opposite directions, and the patient is asked to indicate the position of the border between the two parts. Threshold disparity was defined as the disparity (relative disparity between the nearest and farthest points of the planes or the cylinder) that gives a critical level of performance with the method of limit. The conventional Titmus stereo test using static visual stimuli was used to assess static depth perception. The measurements were performed in 52 strabismic patients, aged between 4 and 38 years old, who visited Tokyo Medical University Hospital between January 2003 and July 2004. Results: The results showed a poor correlation in the threshold of individual patients between the stereo motion test and conventional Titmus stereo test. For example, the ability to perceive motion in depth (disparity threshold <500 sec of arc) was demonstrated in three of seven patients who were not able to perceive depth using static stimuli (0/9 for Titmus circle). These results suggest that the process of the dynamic element of binocular depth perception is preserved in some of the strabismic patients who lack static stereopsis. Conclusion: This study indicates the importance of testing motion-in-depth perception as well as static depth perception in assessing stereopsis in strabismic patients.

In vivo intravascular laser photodynamic therapy in rabbit atherosclerotic lesions using a lateral direction fiber

This study was performed to evaluate the possibility of inducing regression of atherosclerotic foci by photodynamic therapy (PDT) using hematoporphyrin derivative (HpD).

Coxsackievirus B4 associated uveoretinitis in an adult

Coxsackievirus is a kind of enterovirus, which may cause respiratory and gastrointestinal symptoms, erythema, meningoencephalitis, myocarditis, pericarditis, and myositis. Although Coxsackievirus B4 is apparently a rare cause of chorioretinitis, Coxsackievirus infection and concurrent posterior segment inflammation have been disclosed in a few cases. However, iridocyclitis, scattered haemorrhagic dots, and occlusive retinal vasculitis have not previously reported as being features of Coxsackievirus B4 infectious ocular disease. A 34 year old man was referred to our hospital with a 2 week history of inferior visual field defect and visual loss in his right eye. His left eye was asymptomatic. A few days before the onset of visual manifestations, the patient noted a prodrome of viral infection, consisting of severe headache and high grade fever of 38.0–39.2°C, joint pain, and general malaise. There was no significant medical or family history. At the initial ophthalmic examination, his best corrected visual …

Photodynamic therapy for the prevention of restenosis after angioplasty

The purpose of this study was to evaluate whether photodynamic therapy (PDT) can destroy the proliferating smooth muscle cells and therefore suppress the occurrence of restenosis after angioplasty. PDT following administration of hematoporphyrin derivatives (HpD) 24 hours before irradiation was performed on 30 rabbits immediately (0D), 3 days (3D), 1 week (1W) and 2 weeks (2W) after balloon injury. HpD accumulation of each group was investigated simultaneously. Irradiation of 27 J/10 mm2 from an Hg-Xe flash lamp light transmitted through an 800 micrometers quartz fiber with a diffusing tip was used. All rabbits were sacrificed 4 weeks after balloon injury. The results were expressed in terms of intima:media thickness ratio at the site of fiber contact (I/M) and intima:media area ratio of the cross section (IA/MA). Inhibition of intimal thickening evaluated on the basis of the I/M ratio was recognized in the 3D-, 1W-, and 2W-PDT group. The most effective photoradiation was at the 1W-PDT (I/M equals 0.78 +/- 0.67), but in 2W-PDT intimal necrosis resulting in a small amount of thickness was observed with less media necrosis. ThreeD and 0D PDT effects reduced with media necrosis. We conclude that PDT after angioplasty would be an ideal preventional therapy of restenosis.

Application of decorrelation stretching method to hyperspectral fundus image processing

We have developed a near-infrared hyperspectral imaging system that can acquire both spectral and spatial data covering a 50-degree field at the fundus surface within 5 seconds. Single wavelength band reflectance images with bandwidth of 20 nm have demonstrated that choroidal vascular patterns can be clearly observed as bright images for the central wavelength ranging from 740 to 860 nm, while retinal blood vessels are seen as dark images for that ranging from 740 to 920 nm. It is desirable for clinical use to separate the choroidal vascular patterns image from the retinal blood vessels image. To this end, we have applied the decorrelation stretch to processing of spectral images. We have found the following. Original fundus spectral images have stripes noise. The decorrelation stretch emphasizes the noise and, thus, the noise has to be removed by, for example, DCT (Discrete Cosine Transform) filter beforehand. The choroidal vascular image can be successfully separated from the retinal vascular image. Furthermore, the macular is superimposed on the latter as it should be so from the viewpoint of anatomy. The result suggests that useful information may be extracted by combining hyperspectral images with the decorrelation stretch.

Evaluation of multidirectional fluorescence-sensing laser catheter for the development of an intelligent laser angioplasty system

The differential diagnostic capacity of a multi-directional sensing catheter with intraluminal objects was evaluated by fluorescence analysis following administration of a photosensitizer. The measurement catheter is 1.7 mm in diameter and is constructed with a cross-sectional arrangement of 6 sensor bundle units and a centered guide wire lumen. Fluorescence was analyzed by polychrometer and amplified CCD camera with an image intensifier. The excitation light was 405 nm wavelength obtained from an Xe-Hg lamp using a band pass filter. In vivo and in vitro fluorescence analysis of normal and atherosclerotic rabbit aorta was performed following intravenous administration of 5 mg/kg hematoporphyrin derivatives (HpD) 24 hours before. The multi-directional sensing catheter detected fluorescence spectra independently in real time. In vivo measurement of this catheter showed, relative to the tip of catheter, in which direction there was blood, normal intima, slight intimal thickness, which should not be treated by laser, or areas of atherosclerosis, which can be treated by laser.

Enhanced Laser Ablation of Atherosclerosis using Hematoporphyrin Derivatives

ABSTRACT Enhanced Laser Ablation of Atherosclerosis using Hematoporphyrin Derivatives Yasuhisa Oike, Takayuki Asahara, Tomitsugu Kato, Mikio Usui, Hiromori Shiraishi, Hiroyuki Rakue, Hitoshi Nakajima, Yuuichi Naito,Ikuhiro Yamasawa, ChiharuIbukiyama, Tetsuya Hachiya *, Yoshio Ebihara * The Second Department of Internal Medicine, The Second Department of Pathology *, Tokyo Medical College, Tokyo, Japan