Expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) during small-bowel graft rejection in rats.

BACKGROUND: Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is a critical endothelial adhesion molecule for lymphocyte trafficking to gut-associated lymphoid tissues (GALT) under physiological conditions. It is expressed on special postcapillary venules, that is the high endothelial venules (HEV) in GALT. In this study, we investigated changes in MAdCAM-1 expression during small-bowel graft rejection. METHODS: Orthotopic small-bowel transplantation (SBT) with portocaval drainage was performed from brown Norway (BN) rats to Lewis (LEW) rats. Isografted (LEW --> LEW) and untransplanted animals served as controls. Animals were killed on days 3, 4, 5, 6 and 7 after SBT. Cryostat sections (6 microm thick) were prepared from normal small-bowel tissues and small-bowel grafts, including Peyer patches (PPs). Indirect immunoperoxidase staining was performed using monoclonal antibodies (mAbs) against rat MAdCAM-1 (OST12). RESULTS: In the PPs of controls, MAdCAM-1 antibodies specifically stained the endothelial cells of HEV, which were predominantly located in the interfollicular areas. In the allografts on day 4 after SBT, the MAdCAM-1 expression was weaker on the HEV in the PPs than in the controls. In the lamina propria of controls, a faint expression of MAdCAM-1 on vessels was observed. On day 4 after allogeneic SBT, the MAdCAM-1 was more strongly expressed on the endothelial cells of the vessels at the base of the villi. As rejection developed, the MAdCAM-1 expression on the vessels progressed toward the villus tip. CONCLUSIONS: The change of MAdCAM-1 expression may be involved in the development of small-bowel graft rejection. The vessels at the base of villi, which is associated with lymphocyte recruitment, may become a site of intense immune reactivity in the early phase of small-bowel allograft rejection.

Quantitative study on regenerated retinal pigment epithelium and the effects of growth factor.

PURPOSE: To evaluate the integrity of damaged retinal pigment epithelium (RPE) with normal neural retina in a rabbit model, and to examine the effects of basic fibroblast growth factor (bFGF) on the damaged RPE. METHODS: A 3-port vitrectomy, a retinotomy, and a retinal detachment were made in pigmented rabbit eyes. The RPE was then abraded beneath the neural retina. In one group, 1 microgram(s) of bFGF was injected into the vitreous cavity (bFGF applied group). Zero, 7, 14, 21, and 28 days after the operation, fundus examination and fluorescein angiography were performed. Thereafter, the rabbits were killed, the eyes were enucleated, and the histological features were observed with light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The number of RPE cells in the treated area were counted in all experiments, and the effect of bFGF on the number of regenerated RPE cells was analyzed. RESULTS: Regeneration of the RPE was observed in the treated area at postoperative day 14. The number of regenerated RPE cells showed a linear increase. Regenerated cells observed by TEM were smaller than those of the normal RPE. The difference in the number of regenerated RPE cells between the bFGF-applied and non-applied groups was statistically significant on postoperative days 7 and 21. CONCLUSIONS: Repair of the RPE occurred in a short period of time. Similar RPE repair may be seen in humans. Intravitreal injection of bFGF increased the number of regenerated RPE in this model.

Visual outcome after vitrectomy for diabetic retinopathy. A five-year follow-up.

For 5 years after surgery we measured visual acuity in 56 eyes that had undergone pars plana vitrectomy for proliferative diabetic retinopathy. A total of 44.7% eyes maintained improved visual outcome, 19.6% had unchanged visual acuity, and 35.7% were considered failures, as compared to preoperative measurements. Visual results obtained from each patient's visual acuity measured at 3 months, 6 months, 1 year, and 3 years after surgery were statistically compared with that obtained from the visual acuity at 5 years using the chi 2 test. Results showed that visual results recorded at 3 months and 6 months were significantly different from that recorded at the 5-year follow-up (p < 0.02, respectively). We found a tendency for the visual acuity to change during the initial 6 months after surgery and to stabilize by 1 year. Further analysis showed that the initial instability was due to the presence of preoperative retinal detachment. Postoperative visual functions also worsened with complications such as postoperative retinal detachment, glaucoma, and cataract formation.

Retinal changes in myotonic dystrophy. Clinical and follow-up evaluation.

Retinal changes in myotonic dystrophy include butterfly-shaped pigmentary changes in the macula, reticular pigmentary retinal changes in the midperiphery, and peripheral atrophic polygonal-shaped changes. To assess the prevalence and progressiveness of these changes in a large series, 49 patients with myotonic dystrophy were examined. Of the eyes studied, 26 (26.6%) had butterfly-shaped macular pigmentary changes, 24 (24.5%) had reticular pigmentary retinal changes, and 43 (43.9%) had peripheral atrophic polygonal-shaped changes. Ten patients (18 eyes) had two different types at once. Visual acuity was not severely affected. Electroretinographic examination showed diminished a and b wave amplitudes in eyes with and without retinal changes. Arden ratios on the electrooculogram were normal in 13 of 14 patients tested. During the follow-up period, which exceeded 5 years, 3 of 9 patients had newly developed or enlarged, patterned changes of the pigment epithelium. These results suggest that pigmentary retinal changes in patients with myotonic dystrophy are slowly progressive.

Macular choroidal occlusion in dysplasminogenemia.

The authors describe a family with dysplasminogenemia. This diagnosis was based on a lowered ratio of functional plasminogen activity to immunologic plasminogen antigen level, associated with fundus abnormalities. The proband is a 31-year-old woman with Graves disease who had choroidal occlusive lesions of the macula in both eyes. The results of the laboratory examination indicated that the patient was a homozygote for dysplasminogenemia. Similar examinations of the patient's parents and siblings showed their plasminogen levels to be 50% below normal. The thrombotic tendency in this disorder appeared to be responsible for the pathogenesis of the macular choroidal occlusion.