Glucose levels between the anterior chamber of the eye and blood are correlated based on blood glucose dynamics.

Glycemic control is essential to manage metabolic diseases such as diabetes. Frequent measurements of systemic glucose levels with prompt managements can prevent organ damages. The eye is a glucose highly demanding organ in our body, and the anterior chamber (AC) in the eye has been suggested for a noninvasive blood glucose monitoring site. However, calculating blood glucose levels from measuring glucose levels in AC has been difficult and unclear. In this study, we aimed to examine glucose levels from AC and find a correlation with blood glucose levels. A total of 30 patients with cataracts (men and women, study 1; 7 and 3, study 2; 9 and 11) who visited Keio University Hospital from 2015 to 2018 and agreed to participate in this study were recruited. Glucose levels from AC and the blood were examined by a UV-hexokinase or H2O2-electrode method before/during the cataract surgery. These values were analyzed with regression analyses depending on the groups (blood glucose-ascending and descending groups). In the blood glucose-descending group, glucose levels from AC were strongly correlated with blood glucose levels (a high R2 value, 0.8636). However, the relatively moderate correlation was seen in the blood glucose-ascending group (a low R2 value, 0.5228). Taken together, we showed different correlation ratios on glucose levels between AC and the blood, based on blood glucose dynamics. Stacking data regarding this issue would enable establishing noninvasive blood glucose monitoring from measuring glucose levels in AC more correctly, which will be helpful for proper and prompt managements for glucose-mediated complications.

Evaluation of the anterior chamber angle in pseudoexfoliation syndrome.

BACKGROUND: Pseudoexfoliation syndrome (PEX) is the most frequently identifiable cause of secondary open-angle glaucoma, known as pseudoexfoliation glaucoma. The exact pathophysiology and etiology of PEX and associated glaucoma remains obscure. OBJECTIVES: The purpose of this study was to determine the differences in the morphology of the anterior chamber angle in people with pseudoexfoliation syndrome and pseudoexfoliation glaucoma compared to a control group. We also evaluated the correlation between intraocular pressure (IOP) and pigmentation of the angle with the amount of exfoliated material in the anterior segment. MATERIAL AND METHODS: The study group was composed of 155 eyes from 103 patients aged between 43 and 86 years. Each patient underwent a complete ophthalmological examination. RESULTS: Some difference was found in intraocular pressure between the PEX group and the control group and between the pseudoexfoliation glaucoma group and the control group, but no significant difference was found between the 2 study groups. There was a significant difference in the incidence of some degree of pigmentation in the anterior chamber angle and no difference in the widths of the angle between each group. A significant positive relationship was observed between intraocular pressure and the degree of pigmentation of the anterior chamber angle in both the PEX group and the pseudoexfoliation glaucoma group. CONCLUSIONS: The results of this study indicate that the amount of pigmentation and exfoliation material in the anterior segment significantly correlates with the level of IOP and possibly with the degree of trabecular dysfunction. It seems that for clear identification of PEX and pseudoexfoliation glaucoma factors, clinical assessment appears to be insufficient.

Subconjunctival and topical application of recombinant tissue plasminogen activator in rabbits.

PURPOSE: To quantify fibrin degradation products after topical and subconjunctival administration of recombinant tissue plasminogen activator in rabbits. METHODS: Fibrin formation was induced in the anterior chamber in 25 rabbits. Subsequently, five rabbits received an injection of r-TPA (positive control) in the anterior chamber, another 10 received a subconjunctival injection of r-TPA, and the remaining 10 received instillations of topical r-TPA. Afterwards, samples of aqueous humor were collected and semi-quantitative analysis of fibrin degradation products (FDP) was performed. RESULTS: No statistical differences were noted between the treatment and control groups at any time point. Fibrin degradation products semi-quantification showed statistical improvement in the control group and the subconjunctival group. CONCLUSION: Fibrin degradation products were observed in the anterior chamber after subconjunctival administration of r-TPA. However, it was probably not sufficient to cause fibrin degradation. Topical r-TPA did not effectively absorb anterior chamber fibrin.

Subconjunctival and topical application of recombinant tissue plasminogen activator in rabbits / Uso tópico e subconjuntival de ativador de plasminogênio tecidual recombinante em coelhos

Purpose: To quantify fibrin degradation products after topical and subconjunctival administration of recombinant tissue plasminogen activator in rabbits. Methods: Fibrin formation was induced in the anterior chamber in 25 rabbits. Subsequently, five rabbits received an injection of r-TPA (positive control) in the anterior chamber, another 10 received a subconjunctival injection of r-TPA, and the remaining 10 received instillations of topical r-TPA. Afterwards, samples of aqueous humor were collected and semi-quantitative analysis of fibrin degradation products (FDP) was performed. Results: No statistical differences were noted between the treatment and control groups at any time point. Fibrin degradation products semi-quantification showed statistical improvement in the control group and the subconjunctival group. Conclusion: Fibrin degradation products were observed in the anterior chamber after subconjunctival administration of r-TPA. However, it was probably not sufficient to cause fibrin degradation. Topical r-TPA did not effectively absorb anterior chamber fibrin. .

Objetivo: Quantificar produtos de degradação de fibrina (PDF) após uso tópico e subconjunctival de ativador de plasminogênio tecidual recombinante (r-TPA) em coelhos. Métodos: Formação de fibrina foi induzida na câmara anterior em 25 coelhos. Cinco coelhos foram submetidos a injeção intracameral de r-TPA (controle positivo). Dez coelhos foram submetidos a injeção subconjuntival de r-TPA e dez coelhos foram submetidos a instilação tópica de r-TPA. Amostras de humor aquoso foram coletados e uma análise quantitativa dos produtos de degradação de fibrina foi realizada. Resultados: Não foi observado diferença estatisticamente significativa na degradação de fibrina em nenhum dos momentos estudados quando comparados com o controle. Porém foi observado diferença estatisticamente significante na quantificação do produtos de degradação de fibrina no grupo controle e no grupo subconjuntival. Conclusão: Produtos de degradação de fibrina foi observado nas amostras do grupo subconjunctival, porém, provavelmente não foi suficiente para degradar a fibrin presente. r-TPA tópico não foi efetivo em absorver fibrina na câmara anterior. .

Better surgical method for removing perfluorocarbon liquids from the anterior chamber.

PURPOSE: To describe a surgical method for removing perfluorocarbon liquids from the anterior chamber. METHODS: Perfluorodecalin was noted in the anterior chamber in 2 patients after a vitreoretinal surgery was performed. We removed the perfluorodecalin by using a Rycroft cannula mounted on the tip of a tuberculin syringe with continued irrigation by means of an anterior chamber maintainer. RESULTS: The perfluorodecalin was removed using a single intervention. We did not observe any perfluorodecalin residue in subsequent postoperative examinations in either patient. CONCLUSIONS: The method is simple and safe, and it allows the complete removal of perfluorocarbon liquids from the anterior chamber using a single intervention.

Dual-wavelength polarimetric glucose sensing in the presence of birefringence and motion artifact using anterior chamber of the eye phantoms.

Noninvasive glucose monitoring is being investigated as a tool for effectively managing diabetes mellitus. Optical polarimetry has emerged as one such method, which can potentially be used to ascertain blood glucose levels by measuring the aqueous humor glucose levels in the anterior chamber of the eye. The key limitation for realizing this technique is the presence of sample noise due to corneal birefringence, which in the presence of motion artifact can confound the glucose signature in the aqueous humor of the eye. We present the development and characterization of a real-time, closed-loop, dual-wavelength polarimetric system for glucose monitoring using both a custom-built plastic eye phantom (in vitro) and isolated rabbit corneas (ex vivo) mounted in an artificial anterior chamber. The results show that the system can account for these noise sources and can monitor physiologic glucose levels accurately for a limited range of motion-induced birefringence. Using the dual-wavelength system in vitro and ex vivo, standard errors were 14.5 mg/dL and 22.4 mg/dL, respectively, in the presence of birefringence with motion. The results indicate that although dual-wavelength polarimetry has a limited range of compensation for motion-induced birefringence, when aligned correctly, it can minimize the effect of time-varying corneal birefringence for a range of motion larger than what has been reported in vivo.

Trabecular meshwork in normal and pathological eyes.

PURPOSE: The impact of glycosaminoglycans on intraocular pressure in glaucoma patients and in healthy young or aging subjects is explored. MATERIALS AND METHODS: Thirty small autoptic samples were harvested from the tissue localized around the iridocorneal angle of the eye, taking care not to cause aesthetic damage. The samples came from three groups (young, old, and subjects with glaucoma). All samples were divided in two fragments and both were used for morphological and biochemical analyses. Quantitative data were obtained from image analysis to correlate with biochemical values. All results were statistically analyzed. RESULTS: The findings show the following changes of iridocorneal angle are caused by glycosaminoglycans both in aging and in glacoumatous patients: (1) deposition of fibrous granular material and increased electron density of the structures close to the iridocorneal angle; and (2) strong decrease of hyaluronic acid content and increase of sulfated glycosaminoglycans. CONCLUSIONS: Similar to what happens in other tissues in the body, glycosaminoglycans of the human iridocorneal angle undergo physiological and pathological changes. The trabecular meshwork is the structure responsible for the regulation of the aqueous humor outflow that is often altered in primary open-angle glaucoma patients.

Confirmation of the presence of lens epithelial cells in the anterior chamber after phacoemulsification.

AIMS: To detect the presence of lens epithelial cells in the anterior chamber of the eye at the end of phacoemulsification. METHODS: A prospective observational study was carried out on 50 patients undergoing phacoemulsification. Fluid from the anterior chamber was collected from these patients at the end of phacoemulsification. Thirty samples were processed for detection of viability using calcein AM-propidium iodide. Remaining samples were processed for immunofluorescence detection of alphaA-crystallin and vimentin. The nonparametric Mann-Whitney U test was applied. RESULTS: The presence of lens epithelial cells was confirmed in 27 of the first 30 samples. The total number of cells observed in these 27 samples were 64.70 +/- 58.49. Within these 27 samples, 35.5% were live cells and 64.5% were dead. The cells were present as single cell or in groups. Twenty three percentage samples were also positive for nucleated lens fibres. In the remaining 20 samples, 89% cells were confirmed to be lens epithelial cells. CONCLUSIONS: We show for the first time, the presence of cells in the fluid of the anterior chamber at the end of phacoemulsification. The cells were positive for alphaA-crystallin and vimentin, thereby suggesting that they were lens epithelial cells.

Molecular mechanisms of topical anti-inflammatory effects of lipoxin A(4) in endotoxin-induced uveitis.

Lipoxin A(4) (LXA(4)) is a lipid mediator that plays an important role in inflammation resolution. We assessed the anti-inflammatory effect of LXA(4) on endotoxin-induced uveitis (EIU) in rats. The inflammatory cell number and levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), prostaglandin E(2) (PGE(2)), and protein, as well as expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF), in the anterior chamber of the eye were determined 24 h after lipopolysaccharide (LPS; 200 mug/paw) intradermal injection. The immunohistochemical reactivities of nuclear factor-kappaB (NF-kappaB) and c-Jun were also examined. Topical LXA(4) (1-10 ng/eye) pretreatment decreased the number of inflammatory cells and the protein leakage into the aqueous humor (AqH). In addition, topical LXA(4) (10 ng/eye) inhibited the LPS-induced production of IL-1beta, TNF-alpha, and PGE(2), and expression of COX-2 and VEGF. A decreased activation of NF-kappaB and c-Jun was also found in LXA(4)-treated eyes. It is very interesting that an anti-inflammatory effect was achieved even when LXA(4) (10 ng/eye) was applied topically after LPS challenge, as indicated by the reduction in the cellular and protein extravasations into the AqH. Moreover, topical treatment of corticosteroid prednisolone (200 mug/eye) beginning before or after LPS injection reduced all of the molecular and biochemical alterations promoted on EIU rats in an efficacy similar to that of LXA(4). Together, the present results provide clear evidence that pharmacological activation of LXA(4) signaling pathway potently reduces the EIU in rats. Therefore, LXA(4) stable analogs could represent promising agents for the management of ocular inflammatory diseases.

A newly designed glaucoma drainage implant made of poly(styrene-b-isobutylene-b-styrene): biocompatibility and function in normal rabbit eyes.

OBJECTIVE: To report clinical evaluation, flow patency, and histopathological findings of a novel glaucoma drainage implant (GDI) made of poly(styrene-b-isobutylene-b-styrene) (SIBS) in rabbits. METHODS: In 16 normal eyes, the proximal end of the SIBS GDI was inserted into the anterior chamber while the distal end was placed in the subconjunctival space. A control group underwent implantation of a similarly designed silicone GDI. Slitlamp follow-up and intraocular pressure measurements were recorded. Flow patency was evaluated by injecting 0.01% fluorescein into the anterior chamber. Immunostaining against collagen IV, macrophages, and alpha smooth muscle actin was performed. RESULTS: Slitlamp examination suggested adequate biocompatibility. A low and diffuse bleb was observed in the SIBS group. All SIBS tubes were patent 6 months after insertion. Immunostaining demonstrated noncontinuous collagen deposition. No macrophages or myofibroblasts were visible around the SIBS tubes. In contrast, silicone induced collagen deposition and myofibroblast differentiation. CONCLUSION: This new GDI is clinically biocompatible in the rabbit and maintained 100% patency at 6 months. A remarkable difference was the absence of myofibroblasts in the surrounding tissue in the SIBS group. CLINICAL RELEVANCE: This novel GDI made of SIBS would prevent the feared complication of hypotony and will decrease the amount of subconjunctival fibrosis.

Minimally invasive, direct, real time measurement of drug concentration in the anterior eye.

AIMS: To evaluate a corneal contact lens which effectively turns the anterior chamber of the eye into a cuvette, enabling the concentration of a drug to be measured using absorption spectroscopy. METHODS: A hand held contact lens incorporating optical fibres connected to a spectrograph enabled a beam of light to be directed in, across, and out of the anterior chamber. The device was used to follow the time course of drug concentration in the anterior chamber of rabbit (sedated) and humans, using topical brimonidine or fluorescein (with or without local anaesthesia). Absorbance measurements were taken for a 5-25 second period, repeated every 30 minutes. Drug concentrations were compared using absorbance peak height. RESULTS: Corneal absorption starts to rise rapidly at wavelengths shorter than 315 nm. The light path within the anterior chamber is 6.9 mm (rabbit) and 5.8 mm (human), the absorbance measured also includes a corneal component. Application of fluorescein (three drops of 2% solution) in rabbit allowed detection, 60 minutes later, of a large absorbance peak at 490 nm. In the human eye, the device could not measure fluorescein (applied as in rabbit), but clearly detected brimonidine for 3 hours following topical application of 0.6 mg. Modification of the device to measure fluorescence resulted in the detection of 5.3 nM fluorescein in the ex vivo rabbit eye, an increase in sensitivity of two orders of magnitude over the absorption measurements. CONCLUSION: This device has the potential to allow repeated measurements of drug concentrations in the anterior eye provided the drug has suitable absorption or fluorescence characteristics.

Free-floating melanin particles in the anterior chamber: a normal finding in African eyes?

PURPOSE: Pigment dispersion syndrome (PDS) is a well-described entity with Krukenberg's spindle, heavy trabecular pigmentation and retroilluminating iris defects. We have observed a group of patients in mesoendemic onchocercal communities of Kaduna State, Nigeria, with significant amounts of free-floating melanin in the anterior chamber, normal angle pigmentation and absence of iris defects. A pseudo-Krukenberg spindle forms when the patients are asked to maintain a 2 min head-down posture as is often done when examining eyes for the presence of anterior chamber microfilaria. This spindle gradually disappears (tumbles back) after about 2 min of return to the erect posture. This paper describes this finding, which does not appear to fit into accepted notions of pigment dispersion. METHODS: As part of the seventh annual ivermectin dosing exercise during which evidence of optic nerve damage was sought, 455 patients were examined for the presence of microfilaria in the anterior chamber. A total of 352 had been selected for signs of optic nerve disease during an earlier screening exercise, while 103 belonged to a random sample of 5 years and above. Signs of onchocerciasis were sought, while gonioscopy and intraocular pressure measurements were carried out. RESULTS: Of the 455 (11%) individuals examined, 53 demonstrated this phenomenon. Within the random sample, the prevalence was 20%. These tumbling Krukenberg positive (TK+) individuals are significantly younger than TK- individuals and the prevalence, highest in the first decade, dropped steadily to zero levels over the age of 75. Sex distribution was about equal. There was no difference in intraocular pressure, cup-disc ratio and angle pigmentation. Distributions of sclerosing keratitis and chorioretinitis were not statistically different. Optic nerve disease was more common in TK- but this was attributable to the older age distribution. Five TK+ were re-examined after a period of 7 years and had not developed PDS or glaucoma. Four of the five remained TK+. A familial tendency was noted and hereditary factors may be at play, possibly autosomal recessive. The same phenomenon was noted in two of 44 patients in an ophthalmic clinic in Abuja, Nigeria, an urban, non-endemic city south of Kaduna. CONCLUSIONS: This phenomenon does not fit into accepted notions of PDS and may well be a normal finding.

[High performance liquid chromatography identification of chloracetophenone in ocular tissues in burns induced by gas balloons (an experimental study)]. / Identifikatsiia khloratsetofenona v tkaniakh glaza pri ozhogakh soderzhimym gazovykh ballonchikov metodom vysokoéffektivnoi zhidkostnoi khromatografii (éksperimental'noe issledovanie).

The kinetics of chloracetophenone (CN) in rabbit eyes was studied by high-performance liquid chromatography on a model of experimental third-degree burn. By the end of the first hour after exposure to the lacrimate, CN content was high in all the studied tissues: 28.5 +/- 0.563 x 10(-1) mg/kg in the cornea, 5.08 +/- 0.193 x 10(-1) mg/kg in the anterior chamber humor, and 3.26 +/- 0.123 x 10(-1) mg/kg in the vitreous. After 6 h the content of the irritant dropped almost threefold and was 8.5 +/- 0.403 x 10(-1) mg/kg in the cornea, 1.23 +/- 0.062 x 10(-1) mg/kg in the anterior chamber humor, and 0.017 +/- 0.006 x 10(-1) mg/kg in the vitreous. By the end of 24 h these values were 6.6 +/- 0.221, 1.46 +/- 0.123, and 0.015 +/- 0.005 x 10(-1) mg/kg, respectively, and by day 14 only trace amounts of CN were detected. Hence, CN in the Cheremukha gas balloons can penetrate into the inner structures of the eye and cause severe injuries. Persistence of CN for up to 14 days disordered the metabolic processes and anatomy of the eye. High content of CN during the first 7 days after burn requires adequate pathogenetic therapy.

Use of laser flare-cell photometry to count anterior chamber canine leukocytes and latex beads in vitro.

OBJECTIVE: To determine whether the cell measuring function of a laser flare-cell photometer is accurate and reproducible, using an in vitro model. SAMPLE POPULATION: Leukocytes from 8 clinically normal Beagles. PROCEDURE: Latex beads 11.9 and 6.4 microm in diameter were used to simulate canine WBC and RBC, respectively. Beads were diluted to known concentrations, placed in a model eye, and counted by use of the laser flare-cell photometer. A range of protein diluents from 0 to 2,000 mg/dl was used to suspend beads and simulate anterior uveitis, when cells and protein would be in the aqueous humor. A similar series of experiments were repeated, using leukocytes isolated from the blood of Beagles. RESULTS: The laser flare-cell photometer can count 6.4-microm beads reproducibly and linearly up to a total of 510 cells/mm3, and 11.9-microm beads up to 1,300 cells/mm3 over a protein range of 0 to 2,000 mg/dl. The instrument can also count canine leukocytes reproducibly and linearly up to 1,300 cells/mms over that protein range. CONCLUSIONS AND CLINICAL RELEVANCE: Cell and bead sizes and concentrations and protein concentrations were chosen to mimic the range observed in dogs with uveitis. Because the laser flare-cell photometer accurately counted these cells in a range of protein concentrations in the model eye, it has the potential for use in noninvasive quantitative evaluation and monitoring of uveitis in dogs.

Measurement of protein concentration of aqueous humour in vivo: correlation between laser flare measurements and chemical protein determination.

We studied the correlation between laser flare cell meter photon count/ms and actual protein concentration both in vitro and in vivo. Laser flare cell meter measurement of human albumin concentrations of 0 to 10 g/l showed photon counts/ms from 0.3 +/- 0.3 to 78.9 +/- 3.9. There was a statistically highly significant linear correlation between photon count/ms and human albumin concentration (r = 0.98, p = 0.0001). Laser flare cell meter measurements were done on 39 cataract patients with the mean age of 77.9 +/- 6.7 years. Aqueous humour obtained by peroperative paracentesis was analysed for total protein. The mean photon count/ms before pupillary dilatation was 11.93 +/- 6.03. There was a significant linear correlation (r = 0.4, p = 0.019) between the photon count/ms after pupillary dilatation (mean 14.73 +/- 12.9, range 2.6-62.4) and anterior chamber protein concentration (mean 0.62 +/- 0.27, range 0.23-1.3 g/l) with the linear regression formula being y = 0.231 x -1.105 where y = log protein concentration (g/l) and x = log of photon count/ms. Laser flare cell meter photon counts/ms may be converted into an equivalent anterior chamber total protein concentration using this formula.

Isolation and characterization of a unique natural killer cell inhibitory factor present in the anterior chamber of the eye.

The eye is a classic example of an immunologically privileged organ. Immune privilege in the anterior chamber is a multifaceted phenomenon that may have evolved to protect delicate ocular tissues from immune-mediated damage. The anterior chamber of the eye is lined with corneal endothelial cells, which are terminally differentiated cells that are incapable of regeneration. Since corneal endothelial cells are crucial for maintaining corneal clarity, damage to these cells leads to impairment of vision and, in some cases, blindness. The absence of constitutive expression of MHC class I molecules on corneal endothelial cells makes them potential targets for NK cell-mediated cytolysis. The aqueous humor (AH) that fills the anterior chamber of the eye and bathes the corneal endothelial surface contains numerous immunomodulatory molecules, such as TGF-beta, which may protect the corneal endothelium from NK cell-mediated damage. Functionally significant levels of TGF-beta are present in AH. In this study, we demonstrate that AH inhibits NK cell-mediated cytotoxicity in vitro, but does not affect cytotoxic T lymphocyte-mediated lysis. The inhibitory effect was immediate and occurred without preincubation of NK cells with aqueous humor. The inhibitory factor could not be neutralized by Abs to TGF-beta, but was abrogated by treating AH with proteases. Inhibition was not simply due to lysis of NK cells, since AH did not alter NK cell viability. Initial purification using gel filtration chromatography showed that the activity was restricted to a single elution peak. Analysis of the active fractions by gel electrophoresis indicated that the inhibitory factor was a single protein of approximately 10 kilodaltons. The NK inhibitory factor might be an important modulator for protecting the corneal endothelium from unbridled NK cell-mediated injury and, thus, might be instrumental in preserving vision.

Evaluation of albumin concentration in rabbit anterior chamber with laser flare-cell meter.

To find an appropriate way of using Kowa's laser flare-cell meter in evaluating the anterior chamber albumin concentration, we characterized the relationship among the flare intensity determined with the flare-cell meter in terms of photon count/ms (flare value), flare value converted to albumin concentration, and anterior chamber albumin concentration in drug-treated rabbit eyes. Flare measurement was done in rabbits that received intravenous administration of fluorescein isothiocyanate-labeled albumin and instillation of prostaglandin E1, pilocarpine, or tropicamide. Flare value, anterior chamber fluorescence, plasma fluorescence, and plasma albumin concentration were determined. Anterior chamber albumin concentration was calculated from the plasma albumin concentration and the corrected aqueous/plasma fluorescence ratio. The correlation between the flare value converted to albumin concentration (Albequiv) and the anterior chamber albumin concentration (Albac) had two phases: 1) Linear correlation was found when the flare value was below 100 photon count/ms: Albac = 0.53 Albequiv - 0.006, r = 0.98; 2) When the flare value was above 100 photon count/ms, the correlation was lower and had a different slope. In this condition, the Albac was correlated better with the flare value itself: Albac = 0.0042 [flare value] + 0.17, r = 0.88. The results suggested that anterior chamber albumin concentration is evaluated quantitatively from the converted flare value when the flare value is below 100 photon count/ms and from the flare value itself when the flare value is above that level.

Immunohistochemical evaluation of the integrity of the blood-aqueous barrier in normal and rubeotic human eyes.

BACKGROUND: The integrity of the blood-aqueous barrier (BAB) was analyzed using an immunohistochemical technique for the demonstration of albumin. METHODS: Paraffin sections of 36 normal eyes obtained from eye banks or at autopsy (mean age 62.8 +/- 15.2 years) and 46 eyes with marked iris neovascularization (mean age 54.6 +/- 25.3 years) were formalin-fixed and examined using rabbit anti-human albumin. RESULTS: In normal eyes, albumin staining was found in the iris stroma inside and outside the iris vessels but was not detected across the anterior iris border; albumin was present in the anterior chamber in one eye, but not internal to the nonpigmented ciliary epithelium. In rubeotic eyes, albumin staining extended along the anterior iris in all 46 cases; albumin was demonstrated in the anterior chamber in 31 eyes and along to the nonpigmented ciliary epithelium in 13 eyes. Differences between normal and rubeotic eyes were significant for intensity of albumin staining in the iris stroma and for presence of albumin along the anterior iris, within the anterior chamber, and along the ciliary epithelium (P < 0.001, chi 2 test). CONCLUSION: Our findings indicate that the BAB may be less resistant to leakage in the iris stroma than at the ciliary epithelium. BAB breakdown in rubeotic eyes occurred mainly in the iris; the ciliary epithelium was much less involved. Immunohistochemical staining for albumin appears to be useful for evaluating the integrity of the BAB in human pathologic specimens.

Integrins in human anterior chamber angle.

BACKGROUND: Integrins, which are composed of an alpha and beta subunit, are capable of binding to a number of extracellular matrix proteins and, hence, affect cell adhesion and proliferation. METHODS: The distribution of the integrin beta (beta 1, beta 3-beta 5) and alpha (alpha 1-6 and alpha v) subunits in human anterior chamber angle was studied in eyes from subjects aged 9 months to 81 years using the indirect immunofluorescence technique. RESULTS: Immunoreaction for the beta 1 subunit was found throughout the trabecular meshwork (TM), in the cribriform layer, and in the endothelial lining of Schlemm's canal (SC). Labelling for the alpha 3 subunit was found in the TM and the cribriform layer only. In infant eyes the alpha 5 subunit was present in all three areas with the highest concentration in the cribriform layer, whereas no reaction was observed in adult eyes. The alpha 6 subunit was localized to the endothelium of SC only. Immunoreaction for the alpha v subunit was present in the TM and the cribriform layer of infants and young adults. CONCLUSION: The present results suggest the presence of several integrin heterodimers, acting as potential receptors for laminin, collagen, fibronectin, and vitronectin, in the anterior chamber angle.