T-cell-mediated immune responses in alloepithelial rejection after murine keratoepithelioplasty

PURPOSE

To evaluate the role of delayed-type hypersensitivity (DTH) and cytotoxic T-lymphocyte (CTL) responses on alloepithelial rejection in a murine keratoepithelioplasty model.

METHODS

C3H/He mouse corneal lenticules were grafted around the limbus in BALB/c mice, and alloepithelial rejection was assessed by microscopic evaluation. The relation between rejection scores and DTH or CTL responses to donor antigens was assessed by Spearman correlation analysis. Suppression of DTH responses by induction of anterior chamber-associated immune deviation (ACAID) was used to evaluate the contribution of DTH responses to allograft rejection. CTL responses were evaluated by in vitro and in vivo depletion of CD4+ or CD8+ cells.

RESULTS

DTH responses, which developed 2 weeks postoperatively, correlated significantly with rejection scores (correlation coefficient r = 0.55). ACAID induction by anterior chamber inoculation of C3H/He splenocytes significantly suppressed allospecific DTH responses and alloepithelial rejection. While allospecific CTL responses also developed 2 weeks postoperatively and increased by 4 weeks, CTL responses did not exhibit positive correlation with rejection scores (r = -0.36, P = 0.076). The CTL responses were mediated exclusively by CD8+ cells. Although in vivo depletion of CD8+ cells abolished the induction of CTL responses, it did not prevent allograft rejection. Immunohistochemistry showed infiltration of CD4+ and CD8+ cells into the alloepithelium. Positive staining for interferon gamma but not interleukin 4 further implicated the participation of a DTH response.

CONCLUSIONS

Allograft rejection after keratoepithelioplasty appears to be mediated primarily by DTH responses, with CTL responses playing only a minor role perhaps in modifying the development of rejection.

The effect of nitric oxide on the contractile tone of Müller cells

The effect of nitric oxide (NO) on the contractile tone of Müller cells was investigated. Müller cells, isolated from the retina of chick embryos, were cultured on thin sheets of silicone. S-Nitro-N-acetyl-DL-penicillamine (SNAP), an NO donor, was applied in the presence or the absence of carboxyl phenyltetramethylimidazole oxide (C-PTIO), an NO scavenger. The contractile tone of Müller cells was assessed by the extent of wrinkles created on the silicone sheets. The change of contractile tone was evaluated quantitatively by digitizing the photograph before and after the application of SNAP. Relaxation of wrinkles was induced by SNAP. C-PTIO inhibited the SNAP-induced relaxation of wrinkles. These results suggest that NO affects the contractility of embryonic Müller cells and could thus modulate ocular development.

Concentration dependent effects of hydrogen peroxide on lens epithelial cells

AIMS

To evaluate the effects of hydrogen peroxide exposure on the survival and proliferation of cultured lens epithelial cells.

METHODS

TOTL-86 cells, a line of rabbit lens epithelial cells, were used. The survival and proliferation of TOTL-86 cells were quantified by a rapid colorimetric assay (MTT assay). To determine the effects of hydrogen peroxide, TOTL-86 cells were exposed to different concentrations of hydrogen peroxide. To determine the effect of cell numbers on the survival and proliferation of TOTL-86 cells at a fixed concentration of hydrogen peroxide, different numbers of cells were plated and exposed to hydrogen peroxide. To determine whether there is a synergistic effect between hydrogen peroxide and EGF, bFGF, PDGF-AA, and insulin, TOTL-86 cells were exposed to hydrogen peroxide combined with one of these growth factors.

RESULTS

High levels (1 mM) of hydrogen peroxide killed TOTL-86 cells and sublethal levels (100 microM) suppressed their proliferation. From 1 nM to 1 microM of hydrogen peroxide, there was a dose dependent increase in the cell numbers. The initial seeded cell number dramatically affected the response to hydrogen peroxide. Although growth factors showed no synergistic effects with hydrogen peroxide on proliferation, both EGF and insulin, but not bFGF or PDGF, rescued TOTL-86 cells from the sublethal effect.

CONCLUSION

Hydrogen peroxide in cooperation with some growth factors plays an important role in the proliferation of lens epithelial cell.

Nonvitrectomizing vitreous surgery: a strategy to prevent postoperative nuclear sclerosis

OBJECTIVE

The development or progression of postoperative nuclear sclerosis is the most common complication of successful vitrectomy in elderly patients. The authors treated idiopathic epimacular proliferation (EMP) with nonvitrectomizing vitreous surgery in an attempt to prevent postoperative nuclear sclerosis.

DESIGN

Prospective, nonrandomized, comparative case series.

PARTICIPANTS

The authors surgically removed membranes from the sensory retina in 21 eyes of 21 patients with EMP.

INTERVENTION

Neither intravitreal infusion nor vitrectomy of any kind was performed during the procedure. The peeled membrane was left floating in the vitreous cavity in 11 (group 1) eyes and removed in 10 eyes (group 2). Nonoperated fellow eyes served as controls.

MAIN OUTCOME MEASURES

Visual acuity, slit-lamp and/or Scheimpflug photography, and refractometry were performed pre- and postoperatively to evaluate changes in the degree of lenticular opacity.

RESULTS

There was no difference in the rate of development or progression of nuclear sclerosis or the degree of myopic shift between operated and control eyes during the postoperative follow-up period (mean, 9.7 months). No serious complications were noted. There was no difference in postoperative course between patients in the two operative groups.

CONCLUSIONS

Although interpretation of the results of this study is limited due to its small size and short follow-up, nonvitrectomizing vitreous surgery seems to decrease the postoperative development or progression of nuclear sclerosis in patients with idiopathic EMP.

Vitrectomy for rhegmatogenous or tractional retinal detachment with familial exudative vitreoretinopathy

OBJECTIVE

To examine the anatomic features and surgical indications of familial exudative vitreoretinopathy (FEVR) complicated with rhegmatogenous or tractional retinal detachment.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

Twenty-eight eyes of 25 patients who had either clinically suspected or fully diagnosed FEVR. Of these, 25 had rhegmatogenous retinal detachment, 2 had tractional retinal detachment, and 1 had tractional retinal detachment plus vitreous hemorrhage.

INTERVENTIONS

The authors carefully observed the vitreoretinal interface during surgery, studied the clinical and anatomic features of FEVR, and then evaluated the surgical results.

RESULTS

The vitreoretinal adhesions were so strong in the peripheral avascular area that iatrogenic retinal breaks easily occurred in 22 of 28 eyes. In all cases, the bimanual technique with vitreous scissors and forceps was required to dissect the posterior vitreous membrane from the retinal surface. The retina was reattached in 24 of 28 cases (85.7%), and visual acuity improved in 20 eyes (71.4%).

CONCLUSION

Dissection of the vitreous in the peripheral avascular area is very difficult in FEVR, and those patients for whom this procedure was not successfully performed may have a poorer prognosis.

The effects of kallidinogenase on choroidal blood flow in a hypertensive rabbit model

PURPOSE

The purpose of the present study was to investigate the effects of kallidinogenase on chorioretinal circulatory disorder, on the basis of chorioretinal blood flow and fundus findings, in a renal hypertensive rabbit model.

METHODS

In a renal hypertensive rabbit model produced according to Goldblatt's method, chorioretinal blood flow was continuously measured by noncontact laser Doppler flowmetry (LDF). Ophthalmography was conducted before and 30 minutes after drug administration.

RESULTS

Measurement by LDF revealed 16% reduction in chorioretinal blood flow in the hypertension group compared with the control group. The administration of kallidinogenase dose-dependently increased chorioretinal blood flow in both groups, the hypertension group being more sensitive to kallidinogenase than the control group. In contrast, none of the controls (vinpocetine and DL-alpha-tocopherol nicotinate) exerted effects on chorioretinal blood flow in the hypertension group. Fundus examination demonstrated narrowing of the choroidal arterioles following an increase in blood pressure, and expansion of the arterioles following the administration of kallidinogenase.

CONCLUSION

Kallidinogenase was shown to improve ophthalmic circulation by increasing chorioretinal blood flow in renal hypertensive rabbits.

Change in retinal sensitivity due to excision of choroidal neovascularization and its influence on visual acuity outcome

PURPOSE

Excision of choroidal neovascular membranes (CNV) has been attempted as an alternative to photocoagulation for the management of subfoveal CNV. To evaluate functional results of CNV excision, we studied retinal sensitivity in the area corresponding to the CNV (CNV area).

METHODS

Static microperimetry using a scanning laser ophthalmoscope was performed on 17 eyes before and after CNV excision. We studied whether CNV excision changed retinal sensitivity in the CNV area. To evaluate the relationship between retinal sensitivity and visual acuity, further testing was performed on nine patients who had subfoveal CNV from age-related macular degeneration (ARMD).

RESULTS

Preoperatively, 5 of 17 eyes (29.4%) had retinal sensitivity in the CNV area. Postoperatively, 4 of 17 (23.5%) eyes had retinal sensitivity. Surgery did not significantly change retinal sensitivity in the CNV area (P>0.999). There was a significant correlation between the presence of retinal sensitivity and visual acuity. Postoperative visual acuity of eyes with retinal sensitivity in the CNV area was better than that of the eyes without sensitivity in the patients with subfoveal CNV from ARMD (P = 0.0017).

CONCLUSIONS

In most cases, excision of CNV does not improve central retinal sensitivity, and patients have poor visual outcome. In some cases, however, postoperative sensitivity in the bed of CNV is preserved and visual outcome is relatively good. Better or worse preoperative retinal sensitivity does not predict better or worse visual acuity outcome, respectively.

Identification of the gene responsible for gelatinous drop-like corneal dystrophy

Gelatinous drop-like corneal dystrophy (GDLD; OMIM 204870) is an autosomal recessive disorder characterized by severe corneal amyloidosis leading to blindness, with an incidence of 1 in 300,000 in Japan. Our previous genetic linkage study localized the gene responsible to a 2.6-cM interval on chromosome 1p. Clinical manifestations, which appear in the first decade of life, include blurred vision, photophobia and foreign-body sensation. By the third decade, raised, yellowish-grey, gelatinous masses severely impair visual acuity, and lamellar keratoplasty is required for most patients. Here we report DNA sequencing, cDNA cloning and mutational analyses of four deleterious mutations (Q118X, 632delA, Q207X and S170X) in M1S1 (formerly TROP2 and GA733-1), encoding a gastrointestinal tumour-associated antigen. The Q118X mutation was the most common alteration in the GDLD patients examined, accounting for 33 of 40 (82.5%) disease alleles in our panel of families. Protein expression analysis revealed aggregation of the mutated, truncated protein in the perinuclear region, whereas the normal protein was distributed diffusely in the cytoplasm with a homogenous or fine granular pattern. Our successful identification of the gene that is defective in GDLD should facilitate genetic diagnosis and potentially treatment of the disease, and enhance general understanding of the mechanisms of amyloidosis.

Prevention of visual field defect after macular hole surgery by passing air used for fluid-air exchange through water

PURPOSE

To evaluate the effect on peripheral visual field defects occurring after macular hole surgery of passing air that is used for fluid-air exchange through water before infusion to the eye.

METHODS

We used Goldmann perimetry to measure the visual fields of patients who underwent vitrectomy to manage idiopathic full-thickness macular holes using either room air or humidified air for fluid-air exchange. We retrospectively studied visual fields measured in 39 patients (group 1) who underwent vitrectomy without humidification of air and prospectively studied visual fields measured in 33 patients (group 2) who consecutively underwent vitrectomy with humidified air for fluid-air exchange.

RESULTS

In group 1, nine patients (23%) had peripheral visual field defects, most often located in the inferior or inferotemporal quadrant. No patients (0%) in group 2 had a visual field defect after vitrectomy. The difference between groups 1 and 2 in the proportion of patients with visual field defects after vitrectomy was statistically significant (P = .003).

CONCLUSIONS

Passing air used for fluid-air exchange through water seems to prevent visual field defects after vitrectomy for macular hole surgery. Visual field defects that occur after room air is used may result from desiccation of the retina by room air.

Methicillin-resistant Staphylococcus aureus infections after scleral buckling procedures for retinal detachments associated with atopic dermatitis

OBJECTIVE

To determine the incidence and the clinical course of methicillin-resistant Staphylococcus aureus as a cause of acute-onset infections in patients with atopic dermatitis after a scleral buckling procedures.

DESIGN

A retrospective chart review.

PARTICIPANTS

Two hundred eighty-seven patients (293 eyes) who underwent scleral buckling procedures to treat rhegmatogenous retinal detachments at either Osaka Rosai Hospital or Osaka University Medical School between July 1, 1995, and June 30, 1997, participated. Of these, 32 eyes (10.9%) were associated with atopic dermatitis.

INTERVENTION

Demographic and clinical data were abstracted from patients' medical records.

MAIN OUTCOME MEASURES

The incidence, clinical features, and management of postoperative infections associated with methicillin-resistant S. aureus were studied.

RESULTS

Methicillin-resistant S. aureus infection after scleral buckling procedures was identified in 6 (18.8%) of 32 eyes of patients with atopic dermatitis but in only 1 (0.4%) of the other 261 cases without atopic dermatitis (P < 0.001). The average interval from the scleral buckling procedures to the initial onset of infection was 8.3 +/- 9.1 days (range, 2-28 days). Bacterial infection and inflammation were controlled in four eyes by prompt removal of the infected buckle in combination with vancomycin administration. In the other three eyes, however, repeat intravitreous injections of vancomycin or emergent vitrectomies were required because of the development of endophthalmitis.

CONCLUSIONS

Methicillin-resistant S. aureus is an important causative pathogen of scleral buckling infections, particularly in patients with retinal detachment associated with atopic dermatitis. Preoperative evaluation and intraoperative attention to contamination are recommended to prevent methicillin-resistant S. aureus infections in these patients.

[Multicenter retrospective study of retinal detachment associated with atopic dermatitis]

PURPOSE

Epidemiological and clinical study of retinal detachment associated with atopic dermatitis.

METHODS

A multicenter retrospective study.

RESULTS

We analyzed 417 eyes of 348 patients operated on during the 5 years from 1989 to 1993 and followed up for more than 6 months by vitreo-retina specialists in 33 hospitals throughout Japan. The number of eyes operated increased yearly from 42 in 1989 to 132 in 1993. These were 2.3% of the average number of the eyes operated on for rhegmatogenous retinal detachment during the same period, but when restricted to the Kanto area or further to Tokyo only, the percentage was as high as 3.8% and 4.7% respectively. Clinical characteristics of retinal detachment previously reported, such as traumatic slapping or rubbing of the lids by patients as the most possible pathogenetic factor, and high incidence of cataract and proliferative vitreoretinopathy, were confirmed. The primary surgical procedure was scleral buckling in 78% of the cases and vitreous surgery in 22%, and initial and final reattachment rates were 75.3% and 92.6%, respectively.

Specific detections of the early process of the glycation reaction by fructose and glucose in diabetic rat lens

The glycation reaction by fructose, as well as that by glucose, in control and diabetic rat lens was analyzed by using antibodies which specifically recognize adducts of lysine with fructose and with glucose. Levels of fructose adducts in diabetic rat lens were 2.5 times that of the control, and correlated with sorbitol levels. This was mainly due to enhanced glycation of beta- and gamma-crystallins by fructose under diabetic conditions. These data suggest that glycation by fructose may also play a role in cataract formation under conditions of diabetes and aging.

Anatomic and functional recovery of the fovea after foveal translocation surgery without large retinotomy and simultaneous excision of a neovascular membrane

PURPOSE

To document the anatomic and functional recovery of the fovea after foveal translocation surgery with scleral shortening and simultaneous excision of a neovascular membrane in a patient with age-related macular degeneration.

METHOD

Case report.

RESULTS

The visual acuity of a 54-year-old woman with age-related macular degeneration improved from 20/200 to 20/50 after excision of subretinal neovascular membrane and foveal translocation surgery in the right eye. Fixation shifted inferonasally 0.6 disk diameters, corresponding to the direction of foveal translocation, as shown by scanning laser ophthalmoscope microperimetry. Postoperative optical coherence tomography through fixation disclosed normal foveal concavity and intact retinal pigment epithelium.

CONCLUSION

Anatomic and functional recovery of the fovea was confirmed in a patient with age-related macular degeneration after foveal translocation surgery with scleral shortening and simultaneous excision of a neovascular membrane.

Estimation of the neurovirulence of poliovirus by non-radioisotope molecular analysis to quantify genomic changes

Mutant analysis by polymerase chain reaction and restriction enzyme cleavage (MAPREC) has been developed for poliovirus to determine quantitatively for the presence of genomic changes in particular nucleotide sequences correlate with the characteristic of neurovirulence for monkeys. Currently the MAPREC is scheduled to be used as a routine safety test for oral poliomyelitis vaccine (OPV). Radioisotopes (RI) are used in MAPREC for quantitative determinations, a circumstance likely to limit its use. We investigated the possibility of developing a modified MAPREC, which did not require the use of radioisotopes, and developed a procedure designated NON-RI MAPREC. Conventional MAPREC and NON-RI MAPREC were then used in a series of studies in which analyses were performed on Sabin type 1 and Sabin type 3 attenuated vaccine polioviruses prepared under various conditions. Under the experimental conditions used, the stability of the genome of type 1 virus was shown to be markedly greater than that of the type 3 virus, and the frequency of mutants was observed to vary in relation to both the virus strain and the virus inoculum used. The results of the studies relating to the two analytical procedures used indicated that the reproducibility of both methods was of a similarly high order, but that MAPREC had a somewhat broader range of sensitivity than NON-RI MAPREC. As the quantity of genomic changes in OPV relating to neurovirulent properties are within the range of detection by NON-RI MAPREC, this procedure can be used as a quality control test for OPV.

Vitrectomy for proliferative diabetic retinopathy with asteroid hyalosis

PURPOSE

To characterize the clinical features of proliferative diabetic retinopathy (PDR) with asteroid hyalosis treated by pars plana vitrectomy.

METHODS

Vitrectomy was performed in 26 eyes with PDR accompanied by asteroid hyalosis (7 eyes with vitreous hemorrhage, 6 eyes with tractional retinal detachment with vitreous hemorrhage, and 13 eyes with tractional retinal detachment without vitreous hemorrhage). We observed the occurrence of posterior vitreous detachment intraoperatively and evaluated the clinical characteristics retrospectively.

RESULTS

In 24 eyes, posterior vitreous detachment was slight, necessitating artificial detachment. Of the 26 eyes, 20 experienced iatrogenic retinal breaks and 6 (23%) experienced postoperative retinal detachment due to iatrogenic breaks. Three cases worsened to anterior proliferative vitreoretinopathy and retinal reattachment could not be achieved.

CONCLUSIONS

In vitrectomy for PDR with asteroid hyalosis, and in cases of simple vitreous hemorrhage, surgery should be performed with full understanding of the anatomic characteristics. Notably, if posterior vitreous detachment is not present, the occurrence of iatrogenic retinal breaks is more likely.

Complete epiretinal membrane separation in highly myopic eyes with retinal detachment resulting from a macular hole

PURPOSE

Epiretinal membranes (ERMs) in highly myopic eyes may result in macular holes and subsequent retinal detachment. However, removing friable, thin ERMs from detached retinas is often difficult. We report the efficacy of a diamond-dusted silicone cannula in the removal of ERMs from detached retinas.

METHODS

Seventeen consecutive highly myopic eyes (16 patients) with retinal detachment underwent pars plana vitrectomy with gas tamponade. Peeling of the ERM adjacent to the macular hole was performed using either conventional tools (n = 11) or a diamond-dusted silicone cannula (n = 6). The rate of complete membrane peeling and the effect of membrane removal on the anatomic success rate were compared between groups.

RESULTS

Retinal reattachment occurred in 13 (92.9%) of the 14 eyes in which the ERM was removed completely; redetachment occurred in the other three eyes, with further surgical interventions in two eyes. The reattachment rate was significantly higher (P = .005) when ERM removal was complete than when there was residual ERM. In the initial surgery, the ERM was successfully removed in all 6 eyes (100%) in the diamond-dusted silicone cannula group and in 5 of 11 eyes (45.5%) in the conventional group (P = .041); the reattachment rate was 100% in the diamond-dusted silicone cannula group and 45.5% in the conventional group (P = .005). When a second surgery was performed, the use of the diamond-dusted silicone cannula was also better than conventional tools for removing the residual ERMs, resulting in retinal reattachment.

CONCLUSION

In highly myopic eyes with a macular hole and subsequent retinal detachment, complete ERM removal is closely related to successful retinal reattachment. The diamond-dusted silicone cannula appears to be more effective than conventional tools for removing ERM and may increase the anatomic success rate. Because of the limitations of a small series, a prospective, randomized trial is required to confirm the current beneficial results of using a diamond-dusted silicone cannula.

Purification and characterization of UDP-GlcNAc:Galbeta1-4GlcNAcbeta1-3*Galbeta1-4Glc(NAc)-R(GlcNAc to *Gal) beta1,6N-acetylglucosaminyltransferase from hog small intestine

A beta1,6N-acetylglucosaminyltransferase (beta1-6GnT) responsible for the formation of the beta1,6-branched poly-N-acetyllactosamine structure has been purified 210,000-fold in 2.4% yield from a homogenate of hog small intestine by successive column chromatographies involving CM-Sepharose FF, Ni2+-chelating Sepharose FF, and UDP-hexanolamine-agarose, using an assay wherein pyridylaminated lacto-N-neotetraose (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc-PA) was used as an acceptor substrate, and the reaction product was Galbeta1-4GlcNAcbeta1-3(GlcNAcbeta1-6)Galbeta1-4 Glc-PA. The apparent molecular weight of the purified enzyme was 76,000 under nonreducing conditions. The enzyme has a pH optimum at 7.0 and has no requirement for any divalent metal ions. The Km values for pyridylaminated lacto-N-neotetraose and UDP-GlcNAc were 0.96 and 2. 59 mM, respectively. For its activity, this enzyme was shown to have an absolute requirement of at least a complete LacNAc (LacNAc = Galbeta1-4GlcNAc) residue bound to position 3 of the acceptor Gal residues, i.e. it is capable of acting only on the Gal residues of internal LacNAc units. The data strongly suggest that this enzyme could be involved in generating branches to central positions of preformed as well as growing polylactosamine chains, but not in synthesizing the distal branches to growing polylactosamine chains.

Pneumatic displacement of subretinal hemorrhage without tissue plasminogen activator

OBJECTIVE

To assess the efficacy and complications of intravitreal injection of perfluoropropane gas for displacement of subretinal hemorrhage (SRH), without the use of tissue plasminogen activator.

PATIENTS AND METHODS

Pure perfluoropropane gas (0.4-0.5 mL) was injected into the vitreous cavity in 5 patients with SRH involving the fovea because of age-related macular degeneration (4 eyes) or ruptured retinal arterial macroaneurysm (1 eye). The patients were instructed to maintain a prone position.

RESULTS

Visual acuity ranged from 20/300 to 20/2000 before gas injection. On the day after gas injection, SRH was dramatically displaced in 3 eyes and slightly displaced with a reduction in the thickness of subfoveal hemorrhage in the remaining 2 eyes. Final visual acuity improved in all cases, ranging from 20/15 to 20/220. Three eyes had a final visual acuity of 20/50 or better. Vitreous hemorrhage caused by migration of SRH into the vitreous cavity and retinal detachment each occurred in 1 eye, and both complications were successfully treated by vitrectomy.

CONCLUSIONS

Gas injected into the vitreous cavity can displace SRH without the use of tissue plasminogen activator in some cases. Visual acuity after gas injection may be improved, making this treatment an alternative to evacuation of SRH with vitrectomy.

Homozygosity mapping of a gene responsible for gelatinous drop-like corneal dystrophy to chromosome 1p

Gelatinous drop-like corneal dystrophy (GDLD) is a rare autosomal recessive disorder characterized clinically by grayish corneal deposits of amyloid and by severely impaired visual acuity. Most patients require corneal transplantation. To localize a gene responsible for GDLD, we performed linkage analysis of 10 consanguineous Japanese families with a total of 13 affected members. Homozygosity mapping provided a maximum LOD score of 9.80 at the D1S2741 marker locus on the short arm of chromosome 1. Haplotype analysis further defined the disease locus within a region of approximately 2.6 cM between D1S2890 and D1S2801.

Two distinct kerato-epithelin mutations in Reis-Bücklers corneal dystrophy

PURPOSE

Two patients were diagnosed with Reis-Bücklers corneal dystrophy (RBCD), although the pattern and severity of corneal opacification differed. To see whether there was a genetic basis for these phenotypic variations, we analyzed beta ig-h3, the gene that codes for kerato-epithelin and that contains a mutation (Arg555Gln) that causes RBCD.

METHODS

A 30-year-old man with honeycomb-shaped subepithelial opacities in his central cornea and a 25-year-old man with progressive subepithelial geographic opacities were both considered to have RBCD. We isolated genomic DNA from leukocytes of the two patients and their family members and screened for an Arg555Gln kerato-epithelin mutation. Then we analyzed all exons of the gene using the single-strand conformation polymorphism (SSCP) technique to search for any other kerato-epithelin mutations.

RESULTS

The patient with honeycomb-shaped opacities had an Arg555Gln kerato-epithelin mutation that caused his RBCD, whereas the patient with geographic opacities did not; instead, he had a new kerato-epithelin mutation (Arg124Leu), which cosegregated with his family members.

CONCLUSIONS

The variant of RBCD characterized by honeycomb-shaped opacities is caused by an Arg555Gln kerato-epithelin mutation. On the other hand, a new kerato-epithelin mutation, Arg124Leu, was found to cause the RBCD variant characterized by recurrent epithelial erosions and progressive geographic subepithelial opacification. Codon 124 is a hot spot for kerato-epithelin mutations, where the mutations responsible for three autosomal dominant corneal dystrophies--lattice type I (Arg124Cys), Avellino (Arg124His), and the variant of RBCD with geographic rather than honeycomb opacities (Arg124Leu)--are located.

Novel polymorphisms in the beta ig-h3 gene

We found three novel polymorphisms in the beta ig-h3 gene in patients with gelatinous drop-like corneal dystrophy: (1) a substitution from CTC to CTT at codon 472 that did not alter an amino acid; (2) a substitution from GCG (Ala) to GTG (Val) at codon 480; and (3) a substitution from C to T in intron 10, three nucleotides upstream from the acceptor site of exon 11. The allelic frequencies of the C:T polymorphism at codon 472 and in intron 10 in the Japanese population were estimated to be 0.778:0.222 and 0.954:0.046, respectively. Although the codon 480 substitution was not observed in 54 unrelated healthy Japanese people, the substation did not co-segregate with the disease phenotype, suggesting that this was a rare, non-deleterious alteration.