Abstract: To compare the degree of tilt and decentration of an intraocular lens (IOL), refractive status, and prediction error between eyes that underwent trans-scleral suturing of the IOL within the capsular bag (in-the-bag scleral suturing) and eyes that underwent scleral suturing outside of the bag (out-of-the-bag scleral suturing) because of severe zonular dehiscence.
Abstract: Purpose: To investigate neuroprotective effects of siRNA targeted to caspase-3 against ischemia and reperfusion (I/R) injury in rat eyes. Methods: Retinal ischemia was induced in Wistar rats by increasing the intraocular pressure (IOP) to 110 mmHg for 120 min. To examine the effect of siRNA on rat caspase-3, siRNA was injected into the vitreous cavity 24 h prior to induction of retinal ischemia. Eyes were removed at 2, 7 or 14 days later, and then analyzed for the number of retinal ganglion cells (RGCs), the retinal thickness and the amount of apoptosis of the retinal neural cells (as demonstrated by the TUNEL assay). The amount of caspase-3 mRNA was analyzed by rt-PCR. Differences between groups were evaluated by an unpaired t test. Results: The numbers of RGCs in the saline and non-silencing siRNA controls were reduced significantly at 2 and 7 days after the I/R injury. RGCs were significantly retained in eyes pretreated with siRNA targeted to caspase-3 as compared to the control eyes at 2 days after the I/R injury. Inner retinal thickness in the control eyes was significantly thinner as compared to the treated eyes at 2 and 7 days after the I/R injury. After siRNA treatment, the amount of caspase-3 mRNA was significantly lower when compared to the saline control group. Conclusions: The injection of siRNA targeted to caspase-3 into the vitreous cavity of rat eyes may block caspase-3, and may thus be able to prevent retinal cell death associated with ischemic injury. As inhibition of the apoptosis pathway may provide a neuroprotective effect, examination of new strategies for treating these disorders needs to be undertaken.
Abstract: PURPOSE: To compare higher-order aberrations (HOAs) and visual function in eyes with a toric intraocular lens (IOL) and eyes with a nontoric IOL. SETTING: Hayashi Eye Hospital, Fukuoka, Japan. DESIGN: Case-control study. METHODS: Eyes that had phacoemulsification were enrolled in 1 of the following 3 groups: (1) preoperative corneal astigmatism of 1.00 diopter (D) with a toric IOL (toric group), (2) astigmatism of 1.00 D or more with a nontoric IOL (high-astigmatism group), and (3) astigmatism less than 1.00 D with a nontoric IOL (low-astigmatism group). Ocular and corneal HOAs were measured using a wavefront analyzer. Photopic and mesopic visual acuities at high- to low-contrast visual targets were measured using a contrast sensitivity tester. RESULTS: The mean ocular and corneal total HOAs and 3rd-order aberrations in the toric and high-astigmatism groups tended to be greater than in the low-astigmatism group; HOAs and 3rd-order aberrations at 3 months and HOAs at 6 months were significantly different (P≤.0403). The mean corrected visual acuity did not differ significantly between groups. However, photopic low-contrast visual acuity (LCVA) and mesopic high- to low-contrast visual acuity was significantly worse in the toric and high-astigmatism groups than in the low-astigmatism group (P≤.0210). CONCLUSION: Postoperatively, ocular and corneal HOAs were greater in eyes with a toric IOL and in eyes with high preexisting corneal astigmatism than in eyes with low preexisting astigmatism, which impaired photopic LCVA and mesopic visual acuity. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.
Abstract: PURPOSE: To investigate the long-term effect of surface light scattering and glistenings of various intraocular lenses (IOLs) on visual function and optical aberrations after cataract surgery. DESIGN: Case-control study. METHODS: Thirty-five eyes that underwent implantation of a hydrophobic acrylic, silicone, or polymethyl methacrylate (PMMA) IOL more than 10 years ago were recruited. The scattering light intensity of the surface and internal matrix of the optic was measured using Scheimpflug photography. Visual acuity (VA) was measured using VA charts, and contrast VA and that with glare (glare VA) were examined using a contrast sensitivity tester. Ocular higher-order aberrations (HOAs) were measured using a Hartmann-Shack aberrometer. RESULTS: Mean scattering light intensity of the surface and internal matrix of the optic was significantly higher in the acrylic group than in the silicone and PMMA groups (P < .0001). Mean uncorrected VA, photopic and mesopic contrast VA and glare VA, and HOAs did not differ significantly among groups, although mean corrected VA in the acrylic group was significantly better than that in the other groups (P = .0023). Scattering light intensity of the surface and internal matrix did not correlate with VA, contrast VA, or glare VA, and did not correlate with ocular and internal optic HOAs in the acrylic group. CONCLUSIONS: At more than 10 years postoperatively, visual function, including contrast sensitivity, and ocular HOAs were comparable among eyes that received acrylic, silicone, and PMMA IOLs. Surface scattering and glistenings with the acrylic IOLs were not significantly correlated with visual function and optical aberrations.
Abstract: To examine the effect of anterior capsule relaxing incisions created with a neodymium:YAG (Nd:YAG) laser on prevention of anterior capsule contraction after cataract surgery in high-risk patients.
Abstract: To compare long-term change in corneal astigmatism with advancing age between eyes that underwent sutureless cataract surgery and those that did not undergo surgery.
Abstract: To quantitatively examine changes in macular oedema after phacoemulsification surgery in eyes with diabetic retinopathy (DR) and in eyes without DR.
Abstract: A 20-year-old man who had progressive hemifacial atrophy was examined using fluorescein and indocyanine green angiography. The fundus showed sectional chorioretinal atrophy. Fluorescein angiography showed window defects without leakage. Indocyanine green angiography revealed narrow choroidal vessels with hypofluorescence.
Abstract: Background: Rupture of retinal arterial macroaneurysm has a variety of fundus features. We report a case of ruptured retinal arterial macroaneurysm appearing concomitantly with a retinal tear located beneath the detached internal limiting membrane (ILM) that was apparent during vitrectomy.
Methods: Vitrectomy with ILM peeling was performed on a 50-year-old man for sub-ILM hemorrhage and subretinal hemorrhage caused by ruptured macroaneurysm.
Results: After ILM peeling, a retinal tear was found within the detached ILM. The sub-retinal hemorrhage was aspirated from the retinal tear. The retina was finally reattached.
Conclusions: Extensive sub-ILM hemorrhage may cause retinal tear. Careful intraoperative examination and treatment are needed.
Abstract: Transient retinal ischemia induces the death of retinal neuronal cells. Postischemic damage is associated with the infiltration of leukocytes into the neural tissue through vascular endothelia. The current study aimed to investigate whether this damage was attenuated by the inhibition of Rho/ROCK (Rho kinases) signaling, recently shown to play a critical role in the transendothelial migration of leukocytes.
Abstract: OBJECTIVES: To examine the possible predisposing factors for intraocular lens (IOL) dislocation within the capsular bag (in-the-bag dislocation) and IOL dislocation outside of the capsule (out-of-the-bag dislocation) and to study surgical outcomes of explantation of dislocated IOLs and scleral suturing of posterior chamber IOLs. DESIGN: Retrospective interventional case series. PARTICIPANTS: Thirty-eight eyes of 38 patients who developed in-the-bag IOL dislocation and 24 eyes of 24 patients who experienced out-of-the-bag dislocation. INTERVENTION: Medical records of 62 consecutive patients who underwent IOL exchange surgery for dislocation between 1999 and 2005 were reviewed. MAIN OUTCOME MEASURES: Possible predisposing factors and the other characteristics of in-the-bag and out-of-the-bag IOL dislocations; outcomes of IOL exchange surgery, including visual acuity (VA) and refractive status before and at 12 months after surgery; and serious postoperative complications. RESULTS: Possible major predisposing factors for in-the-bag IOL dislocation were pseudoexfoliation (17/38 [44.7%]), retinitis pigmentosa (4/38 [10.5%]), the status after vitrectomy (2/38 [5.3%]), trauma (2/38 [5.3%]), and a long axis (2/38 [5.3%]), whereas those for out-of-the-bag dislocation were secondary IOL implantation (11/24 [45.8%]), surgical complications (3/24 [12.5%]), mature cataract (3/24 [12.5%]), and pseudoexfoliation (2/24 [8.3%]). The interval between IOL implantation and exchange surgery was significantly shorter for the in-the-bag dislocation group than for the out-of-the-bag dislocation group (P = 0.0006). Mean uncorrected VA improved significantly after IOL exchange (P = 0.0080), and corrected VA also tended to improve, although the improvement was not significant (P = 0.0704). Mean absolute value of spherical power decreased significantly after surgery (P = 0.0008), whereas refractive astigmatism showed a significant increase (P = 0.0003). The primary serious complications after surgery were a marked rise in intraocular pressure (12/62, 19.4%), retinal detachment (4/62, 6.5%), and redislocation (2/62, 3.2%). CONCLUSIONS: Possible major predisposing factors for in-the-bag IOL dislocation are pseudoexfoliation, retinitis pigmentosa, the status after vitrectomy, and trauma, whereas those for out-of-the-bag dislocation are secondary implantation, surgical complications, and mature cataract. After IOL exchange surgery, corrected VA does not improve markedly. Because the incidence of postoperative complications after IOL exchange with scleral suturing is high, the use of other surgical techniques should be considered.
Abstract: PURPOSE: To evaluate the efficacy of autologous plasmin (AP)-assisted vitrectomy for stage 5 retinopathy of prematurity (ROP). DESIGN: Interventional case series. METHODS: Six consecutive eyes of four children with stage 5 ROP were treated. The patients' ages at the surgery ranged from five to eight months after birth. Four eyes showed closed-closed configuration and two eyes showed open-open configuration. After lensectomy and dissection of the anterior proliferative membrane, 0.03 to 0.22 International Unit (IU) of AP was administrated into the vitreous cavity. After 15 to 30 minutes of incubation, the proliferative membrane was treated. RESULTS: The proliferative membrane was removed successfully without iatrogenic retinal break. Complete reattachment of the posterior pole retina was achieved in all six eyes (100%). No obvious complication was observed in the follow-up period, which ranged from 11 to 14 months. CONCLUSIONS: These results suggest the benefit of AP in the vitrectomy for treatment of stage 5 ROP.
Abstract: PURPOSE: To evaluate quantitative choroidal dye filling velocity in patients with Vogt-Koyanagi-Harada disease (VKH) before and after corticosteroid treatment using indocyanine green (ICG) angiography. METHODS: ICG angiography was performed in seven VKH patients before and after systemic corticosteroid treatment. Choroidal dye curves were obtained by image analysis software and analyzed using an exponential model. The model's time constant (tau) was used to evaluate choroidal dye filling velocity. RESULTS: Compared with controls, acute phase choroidal tau values in VKH patients were significantly longer, suggesting choroidal circulation disturbance. During the recovery phase, choroidal tau values were significantly shortened, suggesting choroidal circulatory disturbance improvement. CONCLUSION: Choroidal dye filling velocity may be useful for VKH diagnosis and verification of corticosteroid treatment effectiveness.
Abstract: PURPOSE: To investigate the effects of intravitreal injection of nattokinase (subtilisin NAT), a serine protease that is produced by Bacillus subtilis (natto), for induction of posterior vitreous detachment (PVD). METHODS: Different doses of nattokinase (1, 0.1, or 0.01 fibrin-degradation units [FU]) or physiologic saline as a control were injected into the vitreous cavity of rabbit eyes. Scanning electron microscopy was used to observe the retinal surfaces of four rabbit eyes per concentration. Histologic alterations were assessed by light microscopy, using four eyes from each group. Electroretinography (ERG) was performed to observe retinal function, ranging from 1 hour to 1 week after the nattokinase (1 or 0.1 FU) or saline solution administration, using four eyes from each group at each time point. Also, findings in all rabbits were monitored by slit lamp examination and by indirect ophthalmoscopy with a 20-D lens. RESULTS: Scanning electron microscopy showed smooth retinal surfaces, indicating the occurrence of PVD at 30 minutes after intervention in all the experimental eyes injected with 0.1 or 1.0 FU nattokinase, but none of the control eyes. Light microscopy and ERG analysis showed no critical change even after the use of 0.1 FU nattokinase, an amount sufficient to induce PVD. However, toxicity in the forms of preretinal hemorrhage and ERG changes was noted with the higher dose (1 FU) of nattokinase. CONCLUSIONS: The results suggested that nattokinase is a useful enzyme for pharmacologic vitreolysis because of its efficacy in inducing PVD.
Abstract: Ocular symptoms of transthyretin (TTR)-related familial amyloidotic polyneuropathy (FAP) suggest that ciliary pigment epithelium (CPE) may synthesize TTR and its TTR may lead to amyloid formation in addition to TTR from vessels and retinal pigment epithelium (RPE). To clarify sites of TTR synthesis in ocular tissues, we performed in situ hybridization and reverse transcription-polymerase chain reaction (RT-PCR) for qualitative detection of TTR mRNA. In addition, we quantified levels of TTR mRNA expression by means of real-time quantitative RT-PCR. Furthermore, although TTR is an anti-acute phase protein in serum level, no reports on changes in TTR expression in ocular tissues during acute inflammation exist. To investigate changes in TTR expression in ocular tissues during inflammation, we induced uveitis by endotoxin challenge in rabbits and used real-time quantitative RT-PCR to examine changes in TTR mRNA expression in ocular tissues. In situ hybridization and RT-PCR qualitatively demonstrated TTR mRNA not only in RPE but also in CPE. Real-time quantitative RT-PCR showed that the level of TTR mRNA expression in the CPE was about one-third of that in the RPE. TTR mRNA expression in ocular tissues decreased as the degree of inflammation increased. These results suggest that TTR synthesized in the CPE may lead to ocular manifestations, especially glaucoma, in FAP. TTR mRNA also acts as an anti-acute phase reactant in ocular tissues.
Abstract: PURPOSE: To investigate the effect of exogenous plasmin administration on the activity of endogenous matrix metalloproteinase-2 (MMP-2) in rabbit and human vitreous. DESIGN: Experimental animal study and interventional case series. METHODS: Human plasmin was injected into rabbit eyes. The active/pro-MMP-2 ratio in vitreous samples was calculated using the gelatin zymography. Scanning electron microscopy (SEM) was performed to observe the retinal surface. To evaluate the time course of MMP-2 activity, vitreous samples were collected after the injection of 0.5 IU of plasmin, and the active/pro-MMP-2 ratio was calculated in the same manner. Immunohistochemical analysis was performed to confirm the presence of MT1-MMP in the rabbit eye. Human vitreous samples obtained from vitreous surgeries were also used for similar studies. RESULTS: The active/pro-MMP-2 ratios in the vitreous after the injection of 0.25 IU or 0.5 IU of plasmin were significantly higher than that of the control (P < .05). SEM demonstrated that plasmin-treated eyes showed a smooth retinal surface that was dose-dependent. Time course evaluation of the active/pro-MMP-2 ratio in the vitreous after the administration of 0.5 IU of plasmin found a significant difference between the 5 and 15 minutes data points compared with that seen for the control. Immunohistochemical study revealed the presence of MT1-MMP in the inner retina. In human samples, the active/pro-MMP-2 ratio after the plasmin injection was significantly higher than the ratio observed before injection. CONCLUSIONS: Our results suggested that activation of endogenous MMP-2 by exogenous plasmin is associated with the induction of posterior vitreous detachment.
Abstract: PURPOSE: To evaluate the effectiveness and safety of trans-Tenon retrobulbar triamcinolone injection for macular edema associated with branch retinal vein occlusion (BRVO) after vitrectomy. DESIGN: Prospective interventional case series. METHODS: The study included 20 eyes of 20 patients with BRVO, characterized by macular edema lasting more than 3 months after vitrectomy. Trans-Tenon retrobulbar injection of 40 mg triamcinolone was performed, and visual and anatomic responses were evaluated. RESULTS: Mean foveal thickness was 499.4 +/- 209.1 microm preoperatively, 281.8 +/- 110.1 microm at 2-week follow-up, and 196.9 +/- 92.1 microm at 6-month follow-up (P < .0001, at 2 weeks and 6 months, paired t test). Improvement of visual acuity by at least 0.2 logMAR (logarithm of the minimum angle of resolution) was seen in 14 (70%) of the 20 eyes. CONCLUSIONS: Trans-Tenon retrobulbar injection of triamcinolone may be an alternative for additional treatment of eyes with BRVO that remains after vitrectomy.
Abstract: PURPOSE: To evaluate changes in retinal and choroidal circulation after subtenon triamcinolone acetonide (TA) injection for diabetic macular edema. DESIGN: Prospective interventional case series. METHODS: Thirteen eyes of 13 patients with diabetic macular edema were studied. Fluorescein and indocyanine green angiograms were performed at three periods: before the injection and 1 week and 6 months after subtenon injection of TA (40 mg). Retinal arteriovenous passage time (as an indicator of retinal circulation) and choroidal tau (as an indicator of early filling velocity of choroid) were obtained with image analysis software. RESULTS: Choroidal tau values before and 1 week after subtenon TA injection were, respectively, 3.2 +/- 0.4 and 4.0 +/- 0.7 seconds, which showed a significant delay (P = .01, Wilcoxon signed-rank test). The delayed choroidal tau values returned to pretreatment level at 6 months after TA injection. In contrast, the arteriovenous passage time remained unchanged. CONCLUSION: Subtenon TA injection transiently influences choroidal blood flow.
Abstract: PURPOSE: To investigate ultrastructural changes in the aqueous outflow route and discuss the mechanisms associated with intraocular pressure (IOP) elevation in a patient with presumably early stage Chandler's syndrome. METHODS: A 47-year-old man underwent trabeculectomy because of elevated IOP. A specimen obtained during surgery was studied by transmission electron microscopy. RESULTS: Electron microscopy showed the presence of a monolayer composed of corneal endothelium-like cells and thick basement membrane-like material. Neovascularization was also observed in the corneoscleral trabeculum. CONCLUSIONS: Our results indicate that several mechanisms, including the formation of basement membrane-like tissue, infiltration of inflammatory cells and neovascularization, might contribute to the elevation of IOP in Chandler's syndrome. These may occur even when there is no history of conspicuous inflammatory reaction in the anterior ocular segments.
Abstract: PURPOSE: A decrease in beta-amyloid(1-42) (Abeta42) and an increase in tau in the cerebrospinal fluid are reported to be characteristic phenomena in Alzheimer's disease patients. To test the idea that Abeta42 and tau contribute to the development of retinal diseases, we measured Abeta42 and tau concentrations in the vitreous fluid from patients with macular hole (n = 13), diabetic retinopathy (n = 15), or glaucoma concurrent with other ocular diseases (n = 8). METHODS: Vitreous samples were collected from patients who underwent vitrectomy, and sensitive and specific enzyme-linked immunosorbent assays were used to determine the concentrations of Abeta42 and tau. RESULTS: By comparison with the levels in the control macular-hole patients (33.9 +/- 7.1 pg/ml for Abeta42; 3.3 +/- 3.2 pg/ml for tau), there was a significant decrease in the Abeta42 level and a significant increase in the tau level in patients with diabetic retinopathy (1.8 +/- 1.9 pg/ml for Abeta42, P = 0.002; 153.7 +/- 71.6 pg/ml for tau, P = 0.041) or glaucoma concurrent with other ocular diseases (2.8 +/- 1.8 pg/ml for Abeta42, P = 0.006; 113.6 +/- 43.1 pg/ml for tau, P = 0.023). CONCLUSIONS: Our findings indicate the possibility of a role for Abeta42 and tau in the pathogenesis of some retinal diseases.
Abstract: PURPOSE: To understand the role of chondroitin sulfate proteoglycans during the development of rat cornea, expression of chondroitin sulfate and versican (PG-M) was studied. METHODS: Chondroitin sulfate and keratan sulfate in rat cornea were analyzed by immunohistochemical techniques. Reverse transcription polymerase chain reaction (RT-PCR) for chondroitin sulfate proteoglycans was performed. Versican expression was studied by RT-PCR, immunohistochemical, and dot blot analyses. Expression of hyaluronan was evaluated histochemically using biotinylated hyaluronan binding protein. RESULTS: Chondroitin sulfate was abundant in rat cornea at postnatal day 1 (P1) and became undetectable at P14. RT-PCR analysis showed that versican mRNA was highly expressed at P1 but was little expressed at P42. mRNAs for other chondroitin sulfate proteoglycans including biglycan, aggrecan, and decorin did not change much between P1 and P42. Expression for all versican splicing isoforms (V0-V3) was detectable from P1 through P14 but was undetectable after P21. mRNA for V0, the largest form with many chondroitin sulfate binding sites, decreased markedly in early stages from P1 to P14, whereas mRNA for V3, the shortest form with no chondroitin sulfate binding site, increased. mRNAs for middle-sized forms, V1 and V2, remained little changed during these periods. Immunohistochemical and dot blot analyses showed that versican is highly expressed at early stages of development and little expressed at adulthood. Similarly, hyaluronan, a versican-bound glycosaminoglycan, was highly expressed at early stages and little expressed at adulthood. CONCLUSIONS: Versican and hyaluronan, which can form a large molecular complex, may play an important role in the early phase of corneal development.
Abstract: PURPOSE: To report the clinicopathological findings for a unique ocular amyloid angiopathy in patients with familial amyloidotic polyneuropathy (FAP) caused by amyloidogenic transthyretin Y114C. DESIGN: Three case reports. METHODS: Retrospective review of clinicopathological findings, course, and treatment of the 3 patients. MAIN OUTCOME MEASURES: Visual acuity, intraocular pressure, fundus photography, fluorescein angiography (FA), indocyanine green angiography, and histopathological analysis. RESULTS: In the 32-year-old patient, in the early stage of FAP, indocyanine green angiography demonstrated multiple sites of hyperfluorescence, with staining along major choroidal veins. Retinal vessels appeared normal clinically and on FA. In the 48-year-old patient, who had late-stage FAP, examination of the fundus revealed pinpoint white amyloid opacities over the retinal surface, sheathing of retinal vessels, and scattered retinal hemorrhages. Fluorescein angiography showed vascular closure, focal staining, and microaneurysms. Indocyanine green angiography revealed multiple sites of hyperfluorescence, with staining along retinal and choroidal vessels. Examination during follow-up revealed that these vascular changes continued to progress. Histopathological study of an eye obtained at autopsy from the 49-year-old patient revealed marked intravascular and extravascular amyloid deposition. CONCLUSIONS: Severe and progressive amyloid angiopathy causing visual disturbance was seen in patients with FAP caused by amyloidogenic transthyretin Y114C.
Abstract: Familial amyloidotic polyneuropathy (FAP) is the common form of hereditary generalized amyloidosis and is characterized by the accumulation of amyloid fibrils in the peripheral nerves and other organs. Liver transplantation has been utilized as a therapy for FAP, because the variant transthyretin (TTR) is predominantly synthesized by the liver, but this therapy is associated with several problems. Thus, we need to develop a new treatment that prevents the production of the variant TTR in the liver. In this study, we used HepG2 cells to show in vitro conversion of the TTR gene by single-stranded oligonucleotides (SSOs), embedded in atelocollagen, designed to promote endogenous repair of genomic DNA. For the in vivo portion of the study, we used liver from transgenic mice whose intrinsic wild-type TTR gene was replaced by the murine TTR Val30Met gene. The level of gene conversion was determined by real-time RCR combined with mutant-allele-specific amplification. Our results indicated that the level of gene conversion was approximately 11 and 9% of the total TTR gene in HepG2 cells and liver from transgenic mice, respectively. Gene therapy via this method may therefore be a promising alternative to liver transplantation for treatment of FAP.
Abstract: We describe a case of vitreous amyloidosis without systemic symptoms in familial amyloidotic polyneuropathy (FAP) associated with Val30Met transthyretin mutation. A healthy 74-year-old woman noticed left blurred vision and floaters in 1992. Severe vitreous opacities were identified in the left eye. The patient displayed no systemic symptoms, and Congo red staining of the biopsy samples of the stomach and duodenum revealed no amyloid deposition. A diagnosis of FAP was confirmed following genetic investigation. Vitrectomy and cataract surgery was performed with intraocular lens implantation in April 1998. Histopathological examination of the vitreous material revealed amyloid fibrils. Intraocular pressure (IOP) gradually elevated and cupping of the optic disc enlarged. Trabeculectomy was performed in February 2000, but postoperative IOP was again elevated and a needling procedure was performed in March 2000. No postoperative recurrence of vitreous opacity has been reported and IOP has remained well controlled. In the present case, ocular manifestations were the only symptoms of FAP and systemic symptoms have not developed, after more than 12 years. FAP should be suspected as the cause in cases of vitreous opacities in patients from areas with endemic foci of FAP.
Abstract: The aim of the current study was to measure the concentrations of erythropoietin in the vitreous fluid and analyze its association with vascular endothelial growth factor (VEGF) in ischemic vitreoretinal diseases. Vitreous fluid samples were collected from patients with proliferative diabetic retinopathy, branch retinal vein occlusion and idiopathic macular hole. Concentrations of erythropoietin and VEGF in vitreous fluid were significantly elevated in patients with proliferative diabetic retinopathy and branch retinal vein occlusion as compared to patients with macular hole. There were no differences in serum concentrations of erythropoietin and VEGF among patient groups. There was significant correlation between erythropoietin and VEGF concentrations in vitreous fluid. Erythropoietin was up-regulated in ischemic disorders and may act as an endogenous neuroprotective factor against ischemic retinal disorders.
Abstract: PURPOSE: Description of cases of traumatic macular hole that appeared concomitant with a ruptured internal limiting membrane (ILM) that was apparent during vitrectomy only after staining with indocyanine green (ICG). METHODS: Vitrectomy with ILM peeling was performed on a 20-year-old man and a 13-year-old boy for treatment of traumatic macular holes. RESULTS: During vitrectomy, the ILM was found to be ruptured along the area of an identified macular hole only after ICG staining. After the vitrectomy, the macular holes were closed and visual acuity improved. However, visual field defect associated with apparent inner-layer retinal damage remained. CONCLUSION: Blunt trauma can cause severe inner-layer retinal damage with rupture of the ILM as well as frank macular hole formation and choroidal rupture.
Abstract: PURPOSE: To investigate the effects of subretinal indocyanine green (ICG) on retinal morphology in rabbit eyes. METHODS: Retinal bleb detachments were produced by injections of ICG at dosages of 25 mg/ml, 5 mg/ml, and 0.5 mg/ml or with an injection of balanced salt solution (BSS) into the subretinal space of albino rabbit eyes. Morphological change was assessed by light and transmission electron microscopy from the viewpoint of dose and time. Some sections were also probed with the TUNEL technique to detect apoptotic cells. RESULTS: At 14 days after subretinal injection of BSS and 0.5 mg/ml ICG, the structure of the retina was well preserved. However, injections of 5 mg/ml or 25 mg/ml caused thinning of the retina, especially loss of the outer retinal layer. In eyes injected with 5 mg/ml ICG, the photoreceptors began disappearing within 3 days after the injection and over time showed the development of retinal atrophy. TUNEL-positive cells appeared abundantly in the photoreceptor layers 1 and 3 days after the injection of 5 mg/ml ICG. Transmission electron microscopy confirmed apoptosis in the photoreceptors. CONCLUSION: These data indicate that subretinal ICG induces apparent morphological damage of the retina in a dose-dependent manner.
Abstract: PURPOSE: To investigate the spatiotemporal expression of glycosaminoglycans during development of the rat retina. METHODS: Hyaluronan and sulfated glycosaminoglycans, including chondroitin sulfate, heparan sulfate and keratan sulfate were detected using biotinylated hyaluronan binding protein, immunohistochemical analysis, respectively, in the rat retina at various stages of development. RESULTS: Hyaluronan was expressed in the nerve fiber layer, inner plexiform layer and outer plexiform layer during early postnatal stages (postnatal day 1-14; P1-P14) and was undetectable after P21. In contrast, hyaluronan was faintly observed in the photoreceptor layer on P7, and gradually increased up to P49. The spatiotemporal expression pattern of chondroitin sulfate was similar to that of hyaluronan. Heparan sulfate was also detected in the nerve fiber layer, inner plexiform layer and outer plexiform layer during early postnatal stages (P1-P14). In addition, heparan sulfate was expressed in the inner limiting membrane during all stages of development. Keratan sulfate was not detected in the retina at any stage of development. CONCLUSIONS: Hyaluronan, chondroitin sulfate and heparan sulfate are expressed in nerve fiber-rich layers during early postnatal stages and may regulate neurite outgrowth. In adulthood, both hyaluronan and chondroitin sulfate are expressed in the photoreceptor layer and may consist of the interphotoreceptor matrix. In addition, heparan sulfate is expressed in the inner limiting membrane throughout the various stages of development and may be associated with the structure of the inner limiting membrane.
Abstract: The purpose of this study is to investigate possible neuroprotective effects of lens epithelium-derived growth factor (LEDGF) against cell death induced by N-methyl-D-aspartate (NMDA) in the rat retina. LEDGF and/or NMDA were intravitreally injected into rat eyes. NMDA-induced retinal death and protective effects of LEDGF were evaluated by morphometric analysis, cell numbers in the ganglion cell layer (GCL) and the thickness of the inner plexiform layer (IPL). Retrograde labeling with a fluorescent tracer (Fluoro-Gold) was applied for counting retinal ganglion cells (RGCs) that survived after NMDA injection. Terminal deoxyribonucleotidyl transferase (TdT)-mediated fluroscein-16-dUTP nick end-labeling (TUNEL) staining was used to evaluate of retinal cell death. Morphometric analysis and retrograde labeling analysis showed that retinal damage induced by NMDA was protected significantly by LEDGF. TUNEL assay revealed that pretreatment with LEDGF prevents NMDA-induced apoptosis. Retinal damage (ganglion and amacrine cells) induced by NMDA was protected by an intravitreal injection of LEDGF.
Abstract: PURPOSE: To describe a case of a patient with macular hole with subretinal indocyanine green (ICG) during vitrectomy. DESIGN: Interventional case report. METHODS: A 66-year-old woman with macular hole underwent a vitrectomy with ICG. RESULTS: After application of ICG into the vitreous, ICG was introduced in the subretinal space. Indocyanine green was found to be present for more than 6 months. Retinal pigment epithelium atrophy appeared at the site of the lesion. CONCLUSIONS: Although ICG may be a useful tool for distinguishing the internal limiting membrane and other tissues careful application is required to prevent side effects.
Abstract: PURPOSE: Postoperative visual field defects are sometimes found after macular hole surgery. We have previously shown that damage to the retina by air infusion from an infusion cannula is a causative factor. To minimize such damage, we modified the infusion cannula and examined its effects experimentally. METHODS: An infusion cannula with a closed tip and openings on four sides was created. Experimentally, a vitrectomy was performed in rabbit eyes using this new infusion cannula or a conventional cannula. After fluid-air exchange at an air pressure of 40 mmHg, eyes were removed and processed for histologic examination. The areas of the retinal damage caused by air infusion were evaluated. RESULTS: The area of retinal damage created by the new cannula was reduced significantly when compared with damage from conventional cannula use. CONCLUSION: This new cannula, designed for the purpose of scattering the air infusion, can reduce retinal damage, which leads to less frequent postoperative visual field defects.
Abstract: PURPOSE: To investigate the long-term histological changes in rabbit retina damaged by infusion air during vitrectomy. METHODS: Fourteen eyes of 14 rabbits were used. A standard three-port vitrectomy with artificial posterior vitreous detachment followed by fluid-air exchange was performed. After the fluid-air exchange, one side port was kept open for 30 s to freely introduce the air into the vitreous cavity under a pressure of 40 mmHg. Four weeks after surgery, indocyanine green angiography and histological examination were performed. RESULTS: At the air-infused area, indocyanine green angiography revealed the filling delay of the choroidal circulation in the early phase. The retinal surface was smooth and the internal limiting membrane was revealed to be intact by scanning electron microscopy. Light microscopy documented the thinning of the photoreceptor layer in the air-infused area. Transmission electron microscopy showed the disarrangement of the retinal pigment epithelium and loss of choriocapillaries. CONCLUSION: Infusion air during vitrectomy causes long-term outer retinal damage after surgery. Thinning of the photoreceptor cells, disarrangement of the retinal pigment epithelium and loss of choriocapillaries reflect the findings that we have observed previously in clinical cases. Visual field defect is a complication of vitreous surgery using fluid-air exchange. Although the visual field defects were observed just after surgery, abnormal fundus lesions continued to appear over time after the surgical procedure.
Abstract: PURPOSE: To report the prevalence of vitreous opacities and the outcome of vitreous surgery in patients with familial amyloidotic polyneuropathy (FAP). DESIGN: Observational case series. METHODS: In 37 patients with FAP and the ATTR Val30 Met mutation, vitreous opacities were present in 14 eyes of 9 patients and vitrectomy combined with phacoemulsification and intraocular lens implantation was performed in five eyes of three patients. In six patients with the ATTR Tyr114Cys mutation, vitreous opacities were present in both eyes of all six patients and vitrectomy combined with phacoemulsification and intraocular lens implantation was performed in nine eyes of six patients. The mean follow-up period after vitreous surgery was 20.9 +/- 16.8 months (range, 3 to 52 months). RESULTS: The prevalence of vitreous opacities is much higher in patients with ATTR Tyr114Cys (100%) than in those with ATTR Val30 Met (24%). The mean age at the onset of vitreous opacities was significantly lower in the patients with ATTR Tyr114Cys (37.0 +/- 5.3 years) than in the nine patients with ATTR Val30 Met (52.8 +/- 9.1 years; P <.005). Visual acuity improved in all 14 eyes after vitreous surgery; however, final visual acuity decreased in one eye owing to the occurrence of a central retinal vein occlusion. Vitreous opacities mildly increased in two eyes. CONCLUSIONS: Our data suggest that the ATTR Val30 Met and ATTR Tyr114Cys mutations induce different clinical features of vitreous opacities. Vitreous surgery combined with phacoemulsification and implantation of an intraocular lens is a safe and useful treatment. Careful long-term follow-up should be performed.
Abstract: OBJECTIVE: To elucidate the clinical features and surgical outcomes of the treatment of secondary glaucoma associated with transthyretin (TTR)-related familial amyloidotic polyneuropathy (FAP). DESIGN: Retrospective case study. PARTICIPANTS: Forty-nine Japanese patients with FAP. METHODS: For all patients, measurement of best-corrected visual acuity, intraocular pressure, and visual fields as well as slitlamp and ocular fundus examinations were conducted and compared. In addition, the exact mutation of the amyloidogenic TTR variants was analyzed for all 49 patients with FAP. The TTR mutations included amyloidogenic TTR (ATTR) Val30Met in 41 patients, ATTR Tyr114Cys in 6, ATTR Ser50Ile in 1, and a compound heterozygous mutation of ATTR Val30Met + Arg104His in 1. RESULTS: The onset of secondary glaucoma was defined as elevation of intraocular pressure and glaucomatous changes in visual field defects. Secondary glaucoma was detected in 12 (24%) of the 49 patients. The incidence of secondary glaucoma in patients with the Val30Met mutation (17%) was lower than for the other FAP genotypes (P =.02 using the chi(2) test). Of 20 glaucomatous eyes, amyloid deposition on the pupil and anterior surface of the lens was found in 18 eyes. Amyloid deposition was found prior to glaucoma in 11 eyes and at the first visit to our clinic in another 7 eyes. In the 11 eyes in which the onset of glaucoma occurred following amyloid deposition along the pupil, the mean +/- SD period between the onsets of pupillary amyloid deposition and glaucoma was 2.55 +/- 1.43 years (range, 0.2-4.0 years). Further statistical analyses revealed significant relationships between the onset of secondary glaucoma and both amyloid deposition (P<.001) and vitreous opacity (P<.001). Surgical treatment was required in 15 (75%) of the 20 glaucomatous eyes. In 9 (81%) of the 11 eyes that underwent trabeculectomy, the intraocular pressure was well controlled at or lower than 20 mm Hg during the follow-up period. In the eyes that underwent combined trabeculotomy and sinusotomy (2 eyes), nonpenetrating trabeculectomy (1 eye), or a cyclodestructive procedure (1 eye), the intraocular pressure was poorly controlled. CONCLUSIONS: Glaucoma is not a rare condition in patients with FAP, especially because liver transplantation now enables patients with FAP to live longer. Careful observation of amyloid deposition along the pupil allows the prediction of glaucoma onset.
Abstract: This study shows that interleukin-6 (IL-6) combined with soluble interleukin-6 receptors (sIL-6R) modulates N-methyl-D-aspartate (NMDA)-induced retinal damage. Eyes pretreated with a combined injection of IL-6 and sIL-6R had NMDA administered into the vitreous cavity. Morphometric analysis and retrograde labeling analysis found that pretreatment with either IL-6 or sIL-6R alone did not bring about any neuroprotective effect. However, pretreatment with a combined administration of IL-6 and sIL-6R induced a significant neuroprotective effect against NMDA-induced retinal damage. Apoptotic changes in the retina were assessed by the TUNEL method. The results indicated that pretreatment with IL-6 combined with sIL-6R prevents NMDA-induced apoptosis. Western blotting studies demonstrated upregulation of gp130 expression in the NMDA-injected retina. Present studies suggest that IL-6 combined with sIL-6R provides a neuroprotective effect on NMDA-induced retinal damage.
Abstract: PURPOSE: To report a case of primary malignant B-cell type non-Hodgkin lymphoma originating in the iris. DESIGN: Interventional case report. METHODS: An 83-year-old woman presented with anterior uveitis resulting from primary malignant lymphoma in the iris. Ultrasound biomicroscopy and indocyanine green angiography using a scanning laser ophthalmoscope showed abnormalities in the iris. Diagnostic biopsy of the iris revealed B-cell type non-Hodgkin lymphoma. RESULT: The patient was treated with radiotherapy, and the tumorous lesion resolved. CONCLUSION: Primary lymphoma localized in the iris only is rare. In this case, diagnostic biopsy and radiotherapy of the iris lymphoma provided good results.
Abstract: The regulation of expression of the arginine-recycling enzymes and arginase isoforms in association with inducible nitric oxide synthase (iNOS) in the eye of endotoxin-induced uveitis (EIU) rats is investigated. An animal model of EIU was created in Wistar rats by intravitreal injection of lipopolysaccharide (LPS). mRNAs for argininosuccinate synthase (AS) and arginase I as well as for iNOS, measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), were induced in the eye of EIU rats. iNOS mRNA increased markedly 3 hr after injection, reached a maximum at 6-12 hr, and then decreased at 24 hr. AS mRNA remained little change at 3 hr and increased maximally at 6 hr (by about 3.3-fold), whereas arginase I mRNA increased later and reached a maximum at 12 hr (by about 4.2-fold). iNOS, AS, and arginase I proteins were also induced. AL and arginase II mRNAs remained little changed. In immunohistochemical analysis, iNOS, AS and arginase I were almost colocalized in infiltrated inflammatory cells in the vitreous, iris, ciliary body and inner layers of the retina. In conclusion, AS and arginase I are coinduced with iNOS in infiltrated inflammatory cells in the eyes of EIU rats, and may regulate NO production by changing intracellular concentration of arginine.
Abstract: It is known that the severity of ocular symptoms does not always correlate with the systemic symptoms in patients with familial amyloidotic polyneuropathy (FAP ATTR V30M). The ocular tissues may have their own TTR metabolic system. The aim of this study is to clarify the distribution of amyloid deposition in the ocular tissues and to investigate the relationship between ocular symptoms and histopathological changes. We analyzed histopathologically 9 autopsied eyes taken from 3 Japanese and 6 Swedish patients with FAP ATTR V30M. Localization of amyloid deposition varied among the different cases, but there were some tendencies in the distribution. The degree of amyloid deposition in the ocular tissues was not always correlated with the duration of the disease. The frequency of amyloid deposition in the conjunctiva, iris, trabecular meshwork and vitreous body were 88.9%, 44.4%, 11.1% and 11.1% respectively in the 9 patients. These frequencies in the histopathological changes correlated with the frequencies in the clinical ocular manifestations as previously reported.
Abstract: PURPOSE: To report a case of adult T-cell leukemia (ATL) with unilateral dense vitreous opacities that benefited from vitrectomy.DESIGN: Interventional case report.METHODS: Diagnostic vitrectomy was performed on a 59-year-old man with ATL who had vitreous opacity in the right eye.RESULTS: White infiltration of the retina was noted after vitrectomy. Cytologic examination of the vitreous specimen obtained during surgery revealed infiltration of ATL cells into the vitreous and retina. After vitrectomy and additional chemotherapy, visual acuity improved in the right eye from 20/100 to 25/20.CONCLUSION: Infiltration of the vitreous and retina by ATL is rare. Diagnostic vitrectomy is effective for treatment and visual improvement.
Abstract: OBJECTIVE: Visual field defects are one of the complications of macular hole surgery, and mechanical retinal damage induced by infusion air is a proposed causative factor of this complication. In this study, we examined the fundus to see whether the changes observed corresponded to postoperative visual field defects. DESIGN: Observational case series. PARTICIPANTS: Seventeen eyes of 17 patients who had postoperative visual field defects after vitrectomy for idiopathic macular hole were examined. METHODS: The fundus was examined by ophthalmoscopy and by fluorescein and indocyanine green angiography. MAIN OUTCOME MEASURES: Fundus changes corresponding to postoperative visual field defects. RESULTS: In eight eyes, detectable fundus changes were observed, including regional mottling and degeneration of the retinal pigment epithelium, filling delay of the choroidal circulation, subretinal fibrosis, and epiretinal membrane formation. These findings corresponded exactly to the visual field defects observed. Although the visual field defects had been detected shortly after surgery, fundus changes were detected, on average, more than 8 months after surgery. CONCLUSIONS: Fundus changes become apparent after surgery, and they are progressive. Therefore, it is important to examine eyes with visual field defects for a follow-up period of several years.
Abstract: PURPOSE: A defect in the visual field is one of the serious complications of macular hole surgery. We investigated the relationship between the occurrence of visual field defect and the location of infusion cannula and air pressure during fluid-air exchange. METHODS: We studied 100 eyes from 90 patients with macular holes. All patients underwent preoperative and postoperative visual field testing. Vitreous surgery was performed in a standard three-port fashion, with surgically induced posterior vitreous detachment, fluid-air exchange, and sulfur hexafluoride gas injection. We analyzed differences in surgical methods in three groups. In group A, the infusion cannula was placed inferotemporally, and the air pressure was set at 50 mm Hg. In group B, the infusion cannula was placed inferonasally, and the air pressure was set at 50 mm Hg. In group C, the infusion cannula was placed inferotemporally, and the air pressure was set at 30 mm Hg. RESULTS: Eighteen eyes (18%) showed visual field defects after vitrectomy. The defect was always located contralateral to the infusion cannula. There was no statistically significant difference in the incidence of visual field defects in groups A and B. Decreased air pressure reduced the occurrence of visual field defects significantly (24% in group A versus 4% in group C, P = .011). CONCLUSIONS: The location of the visual field defect correlated with the location of the infusion cannula. The incidence of this visual field defect was influenced strongly by the infusion air pressure. The visual field defect may be caused by the mechanical damage of air infusion.
Abstract: PURPOSE: Visual field defects after vitrectomy can be seen after any surgery involving fluid-air exchange. To elucidate the effect during surgery of the infused air on the retina, the present study investigated the changes in the morphology of the rabbit retina induced by air infusion and the changes resulting from varying amounts of infused air pressure. METHODS: Eighteen eyes of 18 rabbits were used. A standard three-port vitrectomy with artificial posterior vitreous detachment followed by fluid-air exchange was performed in 12 eyes. During the fluid-air exchange, humidified air was infused with an air pressure of 25 or 40 mm Hg for 30 seconds. As a control, vitrectomy without fluid-air exchange was performed in six eyes. The eyes were enucleated and fixed immediately. Specimens were processed and examined by light and scanning electron microscopy (SEM). RESULTS: With SEM, sharply demarcated retinal lesions were observed at the opposite side from the infusion cannula in all eyes in which a fluid-air exchange was performed. At the lesion, the internal limiting membrane was often detached, and the underlying nerve fiber layer was exposed. Light microscopy revealed that the inner retina was most affected, with concomitant swelling of the inner plexiform layer and the inner granular layer. In addition, the retina was often focally detached with adhesion of some retinal pigment epithelial cells to the photoreceptor cells. Increased infused air pressure was accompanied by a significant increase in the area of retinal damage. In contrast, no morphologic change was observed in the control eyes. CONCLUSIONS: Air infusion during vitrectomy can cause mechanical retinal damage in the rabbit retina. The mechanical damage may result in a visual field defect after vitrectomy.
Abstract: We have recently found that remnant lipoproteins (RLPs) and their lipid fractions impair endothelium-dependent vasorelaxation (EDR). This study was aimed at clarifying mechanisms responsible for RLP-induced endothelial dysfunction in isolated rabbit aortas. RLPs were isolated from plasma in hyperlipidemic subjects by use of the immunoaffinity gel mixture of anti-ApoA1 and anti-ApoB100 monoclonal antibodies and ultracentrifugation. Organ chamber experiments showed that EDR impairment was restored by addition of reduced glutathione (GSH) or N-acetylcysteine, antioxidants, into the incubation buffer containing isolated rabbit aortas and RLPs (0.75 mg of triglyceride/mL). Furthermore, the incubation of isolated human red blood cells (RBCs) with RLP and its lipids converted the normal shape of RBCs to echinocytes, but coincubation with antioxidants suppressed the RLP-induced RBC transformation, suggesting that they exerted oxidative damage on RBC surface membranes. Studies with HPLC and the postcolumn chemiluminescence method showed that RLPs contain a substantial amount of phosphatidylcholine hydroperoxides. Peroxidized phosphatidylcholine also impaired EDR and had echinocytogenic action, both of which were suppressed by N-acetylcysteine. RLPs isolated from the plasma of patients under treatment with alpha-tocopherol, an antioxidant, had a lower level of phosphatidylcholine hydroperoxides (15% of the amount in nontreated patients), which was associated with a lack of the inhibitory action on EDR and with lesser effect on RBC transformation. Oxidative damage caused by lipid components in RLPs, especially peroxidized phospholipids, deteriorates cell surface membrane and may be at least partly responsible for RLP-induced impairment of EDR.
Abstract: Exposure of sensitized individuals to antigen can induce allergic responses in the respiratory tract, manifested by early and late phases of vasodilatation, plasma leakage, leukocyte influx, and bronchoconstriction. Similar responses can occur in the skin, eye, and gastrointestinal tract. The early-phase response involves mast cell mediators and the late-phase response is leukocyte dependent, but the mechanism of leakage is not understood. We sought to identify the leaky blood vessels, to determine whether these vessels contained endothelial gaps, and to analyze the relationship of the gaps to adherent leukocytes, using biotinylated lectins or silver nitrate to stain the cells in situ and Monastral blue as a tracer to quantify plasma leakage. Most of the leakage occurred in postcapillary venules (< 40-microns diameter), whereas most of the leukocyte migration (predominantly neutrophils) occurred in collecting venules. Capillaries and arterioles did not leak. Endothelial gaps were found in the leaky venules, both by silver nitrate staining and by scanning electron microscopy, and 94% of the gaps were distinct from sites of leukocyte adhesion or migration. We conclude that endothelial gaps contribute to both early and late phases of plasma leakage induced by antigen, but most leakage occurs upstream to sites of leukocyte adhesion.
Abstract: BACKGROUND: Lacquer crack lesion (LCL) is a complication of human pathologic myopia, accompanied by loss of retinal pigment epithelium (RPE) and break of Bruch's membrane. The present paper describes comparable lesions occurring in prolonged experimental myopia in the chick. METHODS: Form-deprivation myopia was induced by unilateral eyelid suturing on the 1st day after hatching. Bruch's membrane in NaOH hydrolyzed preparations and vascular corrosion casts of the choroidal vasculature were examined with scanning electron microscopy. Histological changes in the retina and choroid were also examined with light and transmission electron microscopy. RESULTS: Pale and linear lesions were found in the myopic chick eyes at the age of 8 weeks. In the lesion area, Bruch's membrane was totally broken up and the network of choriocapillaries was totally ruptured with highly atrophied marginal capillaries. The retina was continuous, but was depressed to form a groove in the lesion with the apparently intact inner retina and degenerated photoreceptor cells. Attenuated fibroblasts encompassed the outer circumference of the lesion. RPE cells were scattered in the tissue space inside the fibroblastic investment and also in the choroidal stroma without their polarity. CONCLUSION: The formation of LCL was suggested to be a result of passive stretch exerted upon Bruch's membrane and the capillary network due to abnormal enlargement of the myopic eyes. These results may promote further understanding of the mechanism regarding the development of human lacquer cracks.
Abstract: BACKGROUND: To clarify the mechanism of chorioretinal atrophy, the morphological changes in choriocapillaris (CC) in myopic chick eyes were investigated. METHODS: Form deprivation myopia was induced in 40 chicks by unilateral eyelid suturing. Vascular corrosion casts of the choroidal vasculature were examined with scanning electron microscopy (SEM). Structural changes in CC capillaries were also examined with transmission electron microscopy (TEM). RESULTS: SEM examination of the casts showed that the CC capillaries in the contralateral control eyes formed an extremely dense network with round or oval intercapillary meshes, whereas the capillaries in the myopic eyes were less dense with wider and more irregular intercapillary meshes. As evidenced with morphometrical analysis, CC in the myopic eyes 4 weeks and older exhibited significantly lesser density and capillary diameter and significantly greater center-to-center distance between adjacent intercapillary meshes than in the control eyes. With TEM, most of the capillaries in the myopic eyes were found to be almost devoid of endothelial fenestrations and had narrowed lumina, particularly evident after the 4th week. CONCLUSION: These results suggest that the decreased CC density caused in myopic chick eyes may be due partly to capillary atrophy and partly to overall stretch of the capillary network caused by abnormal enlargement of the myopic eyes.
Abstract: In the rat trachea, substance P causes rapid but transient plasma leakage. We sought to determine how closely the number, morphology, and size of endothelial gaps correspond to the time course of this leakage. Endothelial gaps were examined by scanning electron microscopy (EM), by transmission EM, or by light microscopy after silver nitrate staining. Substance P-induced leakage of the particulate tracer Monastral blue peaked at 1 min but decreased with a half-life of 0.3 min. The number of silver-stained gaps also peaked at 1 min then decreased significantly more slowly (half-life 1.9 min) than the leakage. Scanning EM revealed two types of endothelial gaps, designated vertical gaps and oblique slits. Vertical gaps predominated at peak leakage, whereas oblique slits became more common as the leakage diminished. Measurements of the mean diameter of vertical gaps made by light microscopy, scanning EM, and transmission EM were all in the range of 0.36-0.47 micron. Fingerlike endothelial cell processes that appeared during gap formation became shorter as the leakage diminished (mean length: 1.44 microns at 1 min compared with 1.06 microns at 3 min after substance P), suggesting a role in gap closure. We conclude that the plasma leakage occurring immediately after an inflammatory stimulus results from the rapid formation of endothelial gaps. Multiple factors, including alterations in gap morphology, gap closure, and changes in driving force, are likely to participate in the rapid decrease in the leakage.
Abstract: PURPOSE: The dependence of plasmalemma Ca2+ influx and Ca2+ release from intracellular stores on Ca2+ activated K+ channels of bovine ciliary muscle (CM) cells were examined. METHODS: The nystatin-perforated patch clamp technique for the measurement of membrane currents and a microscope based fura-2 fluorescence imaging of [Ca2+]i were applied to CM cells freshly dissociated with collagenase and identified with smooth muscle-specific alpha-isoactin. RESULTS: At holding voltages (VH) of > -60 mV, CM cells showed spontaneous transient outward currents (STOCs) and caffeine (> 10(-4) M) induced large transient outward currents (ICAF). Both STOCs and ICAF were abolished by tetraethylammonium chloride (10(-3) M) and charybdotoxin (10(-7) M), but not by apamin (10(-6) M), suggesting that both currents are mediated by Ca(2+)-activated K+ channels similar to those with medium (MK) or large (BK-type) conductance. Both STOCs and ICAF were gradually abolished in the nominally Ca(2+)-free and Co(2+)-containing solutions but were resistant to L-type Ca2+ channel blockers, including nicardipine, verapamil and diltiazem and a N-type channel blocker, omega-contoxin. The [Ca2+]i-elevation during high K+ (100 mM)-depolarization was prevented by Ca(2+)-free and Co(2+)-containing solutions but not by nicardipine. CONCLUSIONS: These results suggest that CM cells possess MK or BK type-like Ca(2+)-activated K+ channels and that L-type Ca2+ channels play minor roles for the maintenance of Ca(2+)-dependent responses in contrast to other types of smooth muscle cells.
Abstract: Plasma leakage in inflammation results from intercellular gaps that form in the endothelium of venules. These gaps and related morphological changes in endothelial cells are not readily seen by light microscopy. In this study we sought to visualize such changes by using the selective binding properties of plant lectins. Acute inflammation was induced in the trachea of pathogen-free F344 rats by injecting substance P intravenously, and 1, 3, or 10 min later the vasculature was perfused with fixative followed by a biotinylated lectin. Lectin binding was localized by avidinbiotin complex-peroxidase histochemistry and viewed in tracheal whole mounts by differential-interference contrast microscopy. The binding patterns of the 20 lectins tested fell into 4 groups. Most of the lectins either bound uniformly to the endothelium of normal and inflamed venules (group 1, e.g., Lycopersicon esculentum lectin) or bound weakly or not at all to venules (group 2, e.g., Maackia amurensis I lectin). The uniform binding of group 1 lectins not only revealed the overall vascular architecture but also made visible intercellular gaps and fingerlike processes at endothelial cell borders in inflamed venules. In postcapillary venules after substance P, the fingerlike processes were present along an average of 32% of the endothelial cell perimeter at 1 min, 25% at 3 min, and 7% at 10 min, compared with a baseline value of 2%. A third group of lectins (group 3, e.g., concanavalin A) bound selectively to focal patches of inflamed venules but bound weakly to normal venules. The fourth group (group 4, e.g., Ricinus communis I lectin) bound preferentially to focal patches in inflamed venules and also bound uniformly to normal venules. The focal binding of group 3 and 4 lectins coincided with sites of plasma leakage marked by extravasation of the particulate tracer monastral blue and was associated with subendothelial components of the vessel wall. We conclude that selected lectins reveal novel features of focal sites of plasma leakage, endothelial gaps, and fingerlike processes at endothelial cell borders in inflamed venules.
Abstract: The century-old histological technique of silver nitrate staining has proven to be extremely useful for visualizing endothelial cell borders and localizing endothelial gaps, but the significance of the staining is still not fully understood. To gain some insight into what silver nitrate stains, we developed a method that enabled us to use scanning electron microscopy with backscattered and secondary electron imaging to examine silver staining at endothelial cell borders of venules of the rat tracheal mucosa. We found that in normal venules, silver lines followed the smooth contour of cell borders. However, 1 min after endothelial permeability was increased by substance P, cell borders were irregular and displaced from the silver lines by as much as 4.3 microns, and the lines were accompanied by three types of silver deposits. Most common (46% of total) were annulus-shaped silver deposits that surrounded endothelial gaps. These deposits averaged 1.5 microns in width, were positioned symmetrically across cell borders, and were located at a depth of 0.3 micron beneath the luminal surface. Many endothelial gaps were partitioned into multiple pores (mean, 2.4) by fingerlike processes of endothelial cells. Surprisingly, the gaps occupied only 5.4% of the total area of the silver deposits and constituted 0.15% of the luminal surface of the leaky postcapillary venules. A second type of silver deposit (19% of total) was positioned asymmetrically with respect to the cell border and marked sites where endothelial cell margins still overlapped but appeared to be vertically separated by obliquely oriented gaps. A third type marked gaps at three-cell junctions; these were no more abundant than deposits elsewhere around the cell perimeter, suggesting that three-cell junctions were not unusually leaky sites. We conclude that silver nitrate marks endothelial cell borders and outlines endothelial cell gaps by staining an element of intercellular junctions. The annular shape of many silver deposits around gaps suggests that junctional elements in the apposing cells are separated during gap formation but are still present at the gap perimeter.
