Stages Of Cataract Research Articles

Оптимизация расчета оптической силы интраокулярной линзы у пациентов с осложненной катарактой на фоне псевдоэксфолиативного синдрома

Background . In recent years the phacoemulsification with IOL implantation (PHACO+IOL) is a «gold» standard for cataract surgery. This requires high refractive outcomes that depend upon a number of reasons. One of those is a change in the IOL position in the eye, which can be caused by dystrophic lesions of the zonular system of lens associated with the pseudoexfoliative syndrome (PEХ). Purpose. To increase the accuracy of IOL power calculations in patients with complicated cataract and pseudoexfoliative syndrome. Material and methods . A comparative analysis of refractive results in phacoemulsification with IOL implantation PHACO+IOL was performed in 57 cases of cataract with PEХ. All clinical materials were divided into two groups based on bio-microscopic characteristics: with initial and advanced PEX symptoms. All patients underwent standard examinations. A comparative analysis of refractive outcomes in the study groups was carried out using the «reverse calculation» method that consists in a recalculation of IOL power based on post-operative examination data in both groups. Results. There was no necessity in any amendments to the IOL power calculation in patients with cataract and initial PEX stage. An error of the calculated IOL power was detected in patients with advanced PEХ stage on an average 0.37±0.12D. Сonclusion. The detected error of the calculated IOL power in patients with advanced PEX stage requires an amendment amendment for A constant Am=A+0.3.

Straylight and Visual Quality on Early Nuclear and Posterior Subcapsular Cataracts

ABSTRACTPurpose: To measure log(s) and OSI parameters, both related to forward light scattering in the eye, in subjects with different kinds of early cataracts—nuclear or posterior subcapsular—and corrected visual acuity (CVA).Methods: 34 eyes of 19 patients ranged between 50 and 75 years old with diagnosed nuclear (14 eyes) or posterior subcapsular cataract (20 eyes) were recruited. Only NO1, NO2, P1, and P2 opacity scores according to LOCS III were included. Observer examination included visual acuity, contrast threshold (Ct), and measurements performed by straylightmeter (straylight parameter log(s)) and double-pass instrument (objective scatter index (OSI)).Results: OSI and log(s) were correlated with LOCSIII in nuclear opacities (p = 0.015 and 0.004, respectively) and in the whole data (p = 0.027 and 0.019, respectively) but did not for posterior subcapsular opacities alone. OSI was strongly correlated with log(s) in nuclear (r = 0.885 and p < 0.001) but not in posterior subcapsular cases (r = 0.382 and p = 0.097). Ct was correlated with log(s) for both cataract types (p = 0.043 for nuclear and p= 0.005 for posterior subcapsular cataract) but not with OSI (p = 0.093 for nuclear and p = 0.064 for posterior subcapsular cataract).Conclusions: OSI and log(s) discriminate early stages of nuclear cataracts when taking LOCS III as reference, so these opacities could be graded by any of those parameters. LOCSIII does not represent the visual condition for posterior subcapsular cataract. Straylightmeter measurements express the loss in contrast sensitivity caused by nuclear and posterior subcapsular opacities. Studies of lens opacities must be separated according to the type of opacity present in eyes.

Other facets of mitochondrial antioxidant in ophthalmology

The role of oxidative stress in the development and progression of age-related diseases in ophthalmology sufficiently studied and proven. However application mitohondrail antioxidant is not enough studied under these pathologies. Objective: To investigate the clinical efficacy Vizomitin with age-related cataract and its influence on the parameters of hydrodynamics eyes. Materials and methods. A clinical study of 2 groups of patients (age 63,8 ± 4,3 years). One group – with age-related cataract in the initial stage, which was appointed Vizomitin® 1–2 drops 3 times a day. Patients of the second group received instillation hypromellose. Results. After 4 months of treatment, the difference in the visual acuity in the study group became true and was 0.1 in podruppe I and 0.05 in the subgroup II (p &lt; 0.05 relative to the same sub-groups at the beginning of treatment). Patients with Vizomitin group after the first month and 4 months after the application was observed a slight tendency to increased intraocular pressure. Also, patients in group I ease the outflow coefficient during the initial survey was 0,28 ± 0,01 and decreased during the second examination after 1 month to 0,25 ± 0,01 difference was not significant. Minute volume of chamber moisture in group I patients at initial assessment was 1,9 ± 0,2 and increased after 1 month to 2,46 ± 0,2 (p &lt; 0.05) and remained the same over the next 3 months. Conclusion. Appointment Vizomitin in patients with an initial stage of cataract leads to a positive therapeutic effect (increase in visual acuity). Patients who used Vizomitin significantly change the hydrodynamic performance. After a month of application is increased production of intraocular fluid and increases its outflow in 4 months.

RETROSPECTIVE INVESTIGATION OF CATARACT MANAGEMENT IN AVIAN SPECIES IN A ZOOLOGIC COLLECTION.

A review of avian cataracts at the Wildlife Conservation Society's Bronx Zoo between 1992 and 2011 was conducted. Ninety cataracts in 54 birds from 42 species were identified. Cataracts were found primarily during examination for ocular abnormalities (29/54, 53.7%) or opportunistically (13/54, 24.1%) and were most commonly diagnosed as mature (22/90, 24.4%). Systemic medical conditions diagnosed in these birds included West Nile virus (4/54, 7.4%), head trauma (3/54, 5.6%), plumbism and Salmonella Pullorum (1/54, 1.9%), Marek's disease (1/54, 1.9%), leukocytosis (1/54, 1.9%), and hyperglycemia (1/54, 1.9%). Cataracts were progressive in seven birds of four species. Unilateral enucleation was performed in 2/54 (3.7%) birds, and 12/54 (22.2%) underwent cataract removal (phacoemulsification in 16 eyes and standard extracapsular cataract extraction in 2 eyes). Concurrent ocular abnormalities, such as corneal scarring and lens-induced uveitis, were seen in 2/18 (11.1%) eyes preoperatively in the group undergoing cataract removal, 2/2 (100%) eyes preoperatively in the group undergoing enucleation, and 33/70 (47.1%) of eyes that did not undergo surgery. For birds undergoing cataract removal, complications included successfully treated cardiorespiratory arrest intraoperatively (1/12, 8.3%) as well as postanesthetic complications of acute respiratory distress and tracheal stricture (2/12, 16.7%). The most common postoperative ocular abnormalities included posterior capsular opacity (4/18 eyes, 22.2%) and corneal scarring (2/18 eyes, 11.1%). Lens cortical regrowth and marked posterior lens capsular opacity occurred in one eye of one bird after phacoemulsification, necessitating a second ocular surgery. A successful outcome, as determined by improved postoperative visual acuity, was seen in 10/12 (83.3%) birds undergoing cataract removal, and 5/12 (41.7%) of these birds were alive >3 yr after surgery. The results of this review will aid clinicians in identifying common stages of cataracts, determining eligibility for cataract surgery, and managing postoperative complications in avian patients.

Effects of two antioxidants; α-lipoic acid and fisetin against diabetic cataract in mice.

The purpose of this study was to determine whether α-lipoic acid and fisetin have protective effects against cataract in a streptozotocin-induced experimental cataract model. Twenty-eight male BALB/C mice were made diabetic by the intraperitoneal administration of streptozotocin (200 mg/kg). Three weeks after induction of diabetes, mice were divided randomly into 4 groups in which each group contained 7 mice; fisetin-treated group (group 1), α-lipoic acid-treated group (group 2), fisetin placebo group (group 3), α-lipoic acid placebo group (group 4). Fisetin and α-lipoic acid were administered intraperitoneally weekly for 5 weeks. Cataract development was assessed at the end of 8 weeks by slit lamp examination, and cataract formation was graded using a scale. All groups developed at least grade 1 cataract formation. In the fisetin-treated group, the cataract stages were significantly lower than in the placebo group (p = 0.02). In the α-lipoic acid-treated group, the cataract stages were lower than in the placebo group but it did not reach to a significant value. Both fisetin and α-lipoic acid had a protective effect on cataract development in a streptozotocin-induced experimental cataract model. The protective effect of fisetin appears as though more effective than α-lipoic acid.

Using ultrasound backscattering signals and Nakagami statistical distribution to assess regional cataract hardness.

This study aims to analyze the protein aggregates spatial distribution for different cataract degrees, and correlate this information with the lens acoustical parameters and by this way, assess the cataract regional hardness. Different cataract degrees were induced ex vivo in porcine lenses. A 25MHz ultrasonic transducer was used to obtain the acoustical parameters (velocity, attenuation, and backscattering signals). B-scan and Nakagami images were constructed. Also, lenses with different cataract degrees were sliced in two regions (nucleus and cortex), for fibers and collagen detection. A significant increase with cataract formation was found for the velocity, attenuation, and brightness intensity of the B-scan images and Nakagami m parameter ( ). The acoustical parameters showed a good to moderate correlation with the m parameter for the different stages of cataract formation. A strong correlation was found between the protein aggregates in the cortex and the m parameter. Lenses without cataract are characterized using a classification and regression tree, by a mean brightness intensity ≤0.351, a variance of the B-scan brightness intensity ≤0.070, a velocity ≤1625m/s, and an attenuation ≤0.415dB/mm·MHz (sensitivity: 100% and specificity: 72.6%). To characterize different cataract degrees, the m parameter should be considered. Initial stages of cataract are characterized by a mean brightness intensity >0.351 and a variance of the m parameter >0.110. Advanced stages of cataract are characterized by a mean brightness intensity >0.351, a variance of the m parameter ≤0.110, and a mean m parameter >0.374. For initial and advanced stages of cataract, a sensitivity of 78.4% and a specificity of 86.5% are obtained.

Macular pigment optical density measurements by one-wavelength reflection photometry--influence of cataract surgery on the measurement results.

The main objective of the present study was the investigation of possible influence of lens opacification on macular pigment optical density (MPOD) measurements. Eighty-six eyes of 64 patients (mean age 73.4 ± 8.3 years) were included in the study. MPOD was prospectively measured using the one-wavelength reflection method (Visucam500, Carl Zeiss Meditec AG) before and after cataract extraction, with implantation of a blue-light filtering intraocular lens (AlconSN60WF). The median of the maximum optical density (MaxOD) and the median of the mean optical density (MeanOD) measurements of macular pigment across the subject group were evaluated. Statistically significant differences were noticed between pre-operative and post-operative measurements, the absolute values were generally lower after cataract extraction. The following median (lower/upper quartile) differences across the group were determined: MaxOD -33.8 % (-46.2 to -19.1 %), MeanOD -44.0 % (-54.6 to -26.6 %). Larger changes were observed in elderly patients [<70 years of age (n = 25 eyes): MaxOD -13.4 % (-20.5 to 3.6 %), MeanOD -23.6 % (-30.5 to -15.3 %) versus patients ≥70 years (n = 61 eyes) MaxOD -40.5 % (-53.2 to -30.1 %), MeanOD -47.2 % (-57.8 to -40.1 %)] and in patients with progressed stage of cataract. MaxOD for lens opacification grade 1 (n = 9 eyes): -27.4 % (-42.1 to -19.6 %), grade 2 (n = 26 eyes): -35.0 % (-44.2 to -25.3 %), grade 3 (n = 21 eyes): -34.4 % (-45.4 to -11.4 %), grade 4 (n = 25 eyes): -32.6 % (-53.2 to -6.4 %), and grade 5 (n = 5 eyes): -53.5 % (-61.7 to -38.7 %) and MeanOD for cataract stage 1 (n = 9 eyes): -42.6 % (-46.0 to -26.0 %), stage 2 (n = 26 eyes): -44.1 % (-51.8 to -26.2 %), stage 3 (n = 21 eyes): -45.7 % (-54.7 to -24.7 %), stage 4 (n = 25 eyes): -39.5 % (-59.4 to -26.1 %), and stage 5 (n = 5 eyes): -57.0 % (-66.1 to -51.4 %). As established by comparison of pre- to post-operative measurements, cataract presented a strong effect on MPOD measured by one-wavelength reflection method. Particular care should therefore be taken when evaluating MPOD using this method in elderly patients with progressed stage of cataract. Future optimization of correcting parameters of scattered light and consideration of cataract influence may allow more precise evaluation of MPOD.

Lysosomal enzymes activity in patients with pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PEX) is a complex systemic disorder of the extracellular matrix affecting the eye and visceral organs. Pseudoexfoliation material deposits on various structures of the anterior segment of the eye and around blood vessels of connective tissue. Animal studies have suggested that the lysosomal trafficking regulator (LYST) gene is potentially important in PEX (Liton et al. 2009). Lysosomes are the cellular recycling centres responsible for the physiologic turnover of cell constituents. Inadequate enzyme activity results in disruption of the degradation process and accumulation of substrates for that specific enzyme, leading to variety of pathological changes. Increasing evidence suggests that the oxidative–antioxidative balance is disturbed in patients with PEX (Uçakhan et al. 2006; Lesiewska-Junk et al. 2013). The lysosomal proteolytic activity is compromised under oxidative stress conditions (Wenger et al. 2013). We studied 52 consecutive patients with PEX (16 males and 36 females), who presented for senile cataract surgery, median 75 years, range 59–89. The reference group consisted of 30 individuals (10 males and 20 females), matched for age and gender, with senile cataract without PEX, median 72 years, range 61–90. Both groups did not differ in stage of cataract nor body mass index and smoking habits. PEX was recognized based on typical material in the anterior segment seen after pupil dilation. The exclusion criteria were systemic and local diseases except cataract and PEX (including diabetes, rheumatoid arthritis, lipid profile disorders, intraocular surgery in history). The activity of four lysosomal enzymes in plasma was assessed as follows: acid phosphatase (AcP) with the use of Bessey method, alpha-1-antitrypsin (AAT) using Eriksson method, cathepsin D (CAT D) using Anson method and arylsulphatase (AS) using Robinson method. Kolmogorov–Smirnov test was used to assess normality of the data. Mann-Whitney test was used for comparison of data from small size independent samples. P-value of <0.05 was considered statistically significant. The values of activities of assessed enzymes are shown in Table 1. Reduced activity of proteolytic enzymes and subtle inflammatory processes may trigger the PEX-specific fibrotic matrix process (Schlötzer-Schrehardt 2012). Although Mizuno et al. (1980) found acid phosphatase activity significantly higher in the aqueous humour of eyes with PEX than in that of cataractous eyes without PEX, in our group, these values in blood plasma appeared to be lower in PEX patients. According to Cumurcu et al. (2008) serum A-1-AT activity was increased in patients with PEX, which is in accordance with our results. It may indicate the role of inflammation in this group of patients. To our best knowledge, this is the first study on AS and CAT D activities in PEX patients. Our observations may shed light on the complex metabolic contribution and molecular pathway of the disease.

Serum antibodies against βH‐crystallins in the American Cocker Spaniel

ObjectiveTo detect antibodies for lens βH-crystallins in the serum from the American Cocker Spaniel (ACS) presenting with and without cataracts and with and without uveitis.Animal StudiedSeventy-three American Cocker Spaniels and six normal Beagles.ProceduresSera were collected from 73 ACSs, including those with normal lenses and those with cataracts, or uveitis. Fractionated, normal Beagle lens βH-crystallins were separated by one- or two-dimensional electrophoresis. The separated lens βH-crystallins were used on immunoblots as sentinel substrates against which the ACS sera were tested for the presence of antibodies against βH-crystallins.ResultsSera from approximately two-thirds of study animals contained antibodies to some βH-crystallin polypeptides, but reactivity varied among patients. Contrary to some hypotheses, serum antibodies to groups of βH-crystallins did not relate to the stages of cataract. However, detailed analysis by two-dimensional immunoblotting and mass spectrometry showed that three spots originating from βA1-crystallin were detected only in sera from cataract patients.ConclusionSerum antibodies to βA1-crystallin may be associated with the development of cataract.

An Increase in Phosphorylation and Truncation of Crystallin With the Progression of Cataracts

BackgroundCataracts are the leading cause of blindness worldwide; however, there is no evidence regarding the direct formation of cataracts. At present, there is no treatment method other than surgery to prevent the formation or progression of cataracts. ObjectiveUnderstanding the protein changes during various stages of cataracts might help realize the mechanism of the formation and progression of cataracts. MethodsLens materials were collected from cataract surgery. Cataracts were classified according to lens opacity using the gradation of the Lens Opacities Classification System. Lens proteins were separated by 2-dimensional polyacrylamide gel electrophoresis. Protein spots were visualized by Coomassie blue staining, and expression patterns were analyzed. Protein spots of interest were excised from 2-dimensional polyacrylamide gel electrophoresis gels, digested in situ with trypsin, and analyzed by mass spectrometry and liquid chromatographic tandem mass spectrometry. ResultsCrystallin was the major protein in the cataract lens, and αA, βB1, αB, and βA4 were the dominant types. Crystallin αB and βA4 increased with the formation of lens opacity. Moreover, phosphorylation and truncation of these proteins increased with the progression of cataracts. ConclusionCrystallin αB and βA4 and phosphorylation and truncation of crystallin in the lens might contribute to the formation of cataracts. In contrast, acetylation was not dominant in the progression of cataracts and did not play major role in the formation of cataracts.

Ionizing Radiation as a Risk Factor for Cataract: What about Low-Dose Effects?

Lens opacities are potential serious consequences of eye exposure to ionizing radiation. Several studies have shown with certainty that radiation cataractogenesis has a much lower threshold than the old radiation protection guidelines of the International Commission on Radiological Protection (ICRP), specifically 2 Gy (Grays) for acute exposure and 5 Gy for fractioned exposure. In April 2011, the ICRP revised its eye dose threshold for cataract induction downwards from 2 Gy to 0.5 Gy, and the occupational annual dose limit from 150 mSv to 20 mSv/year. Moreover, based on previous studies the traditional view that posterior subcapsular opacities are the only signature form of radiation cataract may have to be broadened to cortical cataracts.We present the most recent results on lens opacities and early stages of cataract that were observed for ionizing radiation doses below 1 Gy and which have led the ICRP to decrease the eye lens dose threshold.

Protective effects of ebselen on sodium-selenite-induced experimental cataract in rats

To determine whether ebselen has a protective effect or antioxidative potential in a sodium-selenite-induced experimental cataract model. Fırat University, Elazığ, Turkey. Experimental study. Twenty-one Sprague-Dawley rat pups were randomly divided into a control group, a sodium-selenite-induced-cataract group, and an ebselen-treated group; each group contained 7 rat pups. Rats in the control group received dimethyl sulfoxide (DMSO) intraperitoneally only and rats in the sodium-selenite-induced-cataract group received 30 nmol/g body weight sodium selenite subcutaneously and DMSO intraperitoneally 10 days postpartum. Rats in the ebselen group received 30 nmol/g body weight sodium selenite subcutaneously 10 days postpartum and were treated with 5 mg/kg body weight ebselen once a day for 4 consecutive days. Cataract development was assessed weekly for 3 weeks by slitlamp examination and graded using a scale. Reduced glutathione (GSH), total nitrite, and malondialdehyde (MDA) levels in lens supernatants were measured at the end of 3 weeks. In the control group, all lenses were clear. In the ebselen-treated group, the mean cataract stage was significantly lower than in the sodium-selenite-induced-cataract group (P = .022). The GSH levels were significantly lower in the sodium-selenite-induced-cataract group than in the control and ebselen groups (P < .001). The MDA levels were lower in the ebselen group than in the sodium-selenite-induced-cataract group (P < .001). The mean total nitrite level was significantly lower in the sodium-selenite-induced-cataract group than in the ebselen group (P = .001). Ebselen had a protective effect on cataract development in a sodium-selenite-induced experimental model. The protective effect of ebselen appears to be due to inhibition of oxidative stress. No author has a financial or proprietary interest in any material or method mentioned.

Antioxidant and calcium levels in mature and immature diabetic cataract lens

Cataract is considered a major cause of visual impairment in diabetic patients as the incidence and progression of cataract is elevated in patients with diabetes mellitus. The pathogenesis of diabetic cataract development is still not fully understood. Due to increasing numbers of type 1 and type 2 diabetics worldwide, the incidence of diabetic cataracts steadily rises. Even though cataract surgery, the most common ophthalmic procedure worldwide, is an effective cure, the elucidation of patho- mechanisms to delay or prevent the development of cataract in diabetic patients remains a challenge. Furthermore, patients with diabetes mellitus have higher complication rates from cataract surgery. Both diabetes and cataract pose an enormous health and economic burden, particularly in developing countries, where diabetes treatment is insufficient and cataract surgery often inaccessible. Hence the objective of the study was to assess the antioxidant levels and calcium levels in different stages of cataract. Our study showed a significant reduction in lens antioxidant activity with significantly increased calcium levels in mature stage of cataract, suggesting decreased antioxidant activity plays an important role in diabetic cataract by causing deposition of calcium in lens. DOI: http://dx.doi.org/10.3126/ijls.v6i1.5290

Structural and Functional Properties, Chaperone Activity and Posttranslational Modifications of Alpha-Crystallin and its Related Subunits in the Crystalline Lens: N-acetylcarnosine, Carnosine and Carcinine act as Alpha- Crystallin/Small Heat Shock Protein Enhancers in Prevention and Dissolution of Cataract in Ocular Drug Delivery Formulations of Novel Therapeutic Agents

Cataract is a leading cause of blindness worldwide and is responsible for ∼40-80% of the estimated 45 million cases of blindness that occur across the globe. In addition to providing refractive properties to the lens for focusing the image, it is believed that the molecular chaperone function of α-crystallin is essential in preventing the light scattering due to aggregation of other proteins and thus in the maintenance of lens transparency and thereby prevention of cataract. By now, it is fairly acknowledged that chaperoning ability of α-crystallin is instrumental in the maintenance of crystalline lens transparency, and decreased chaperone-like activity of α-crystallin is associated with various types and stages of cataract. A better pharmacological targeting of safeguarding the α-crystallin chaperone activity may aid the development of therapeutic strategies that could evade the need for cataract surgery and revive lens transparency of the cataractous lenses. This article originally summarizes the significance of modulation and enhancing of α-crystallin chaperone activity with imidazole-containing dipeptides N-acetylcarnosine, carnosine and carcinine in consequence to prevent, delay or dissolve the human cataract. A growing evidence and discussion of recent patents are presented in this study that demonstrate the ability of N-acetylcarnosine (lubricant eye drops) or carcinine (lubricant eye drops) (universal antioxidant and deglycation agent) resistant to enzymatic hydrolysis with carnosinase to act as pharmacological chaperones, to decrease oxidative stress and ameliorate oxidative and excessive glycation stress-related eye disease phenotypes, suggesting that the field of chaperone therapy might hold novel treatments for age-related cataracts, age-related macular degeneration (AMD) and ocular complications of diabetes (OCD). The therapeutic strategies are highlighted in the study for identifying potential chaperone compounds and for experimentally demonstrating chaperone activity in in vitro and in vivo models of human age-related eye disease, such as cataracts and advanced glycation tissue proteins - engineered systems.

Gender Disparity in Delayed Treatment-Seeking Behavior for Cataract

This study was conducted to explore the role of gender in delayed treatment seeking for cataract at the Impact Jibon Tari Floating Hospital in rural Bangladesh. Existing clinical records were analyzed for patient characteristics based on sex and the role of gender in delayed cataract surgery. A total of 11 174 patients (41.7% female) received surgical treatment for cataract, among which 69.9% (male = 67.7%; female = 73.2%) had visual acuity (VA) of less than 6/60. After adjustment for hypertension, diabetes, side of eye with cataract, and age above 65, women were more likely to come to surgery after VA became less than 6/60 (adjusted odds ratio = 1.19; 95% confidence interval = 1.1-1.29). Gender appeared to play a role in seeking treatment at later stages of cataract. Further qualitative studies are needed to determine the mechanism of delayed treatment among women.

αB-crystallin malondialdehyde, superoxide dismutase, and lutathione peroxidase changes in X-ray irradiated rat lens.

To evaluate αB-crystallin malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) changes in X-ray irradiated rat lens. Eight-week-old Sprague-Dawley male rats received X-ray irradiation to the head with rest of the body protected. The exposure dose ranged from 2 to 25 Grays (Gy). The cataract status were examined by slit lamp and rated with "four-grade systems" post-irradiation. The lens MDA level, and the activities of SOD and GPx were measured in a short-term experiment post-irradiation, and αB-crystallin protein levels were quantified. The lenses of normal control and the X-ray irradiated groups with the dose up to 10 Gy remained transparent throughout the experiment. The lens first appeared tiny scatters, and even lamellar opacities in the posterior capsule 45 days post-irradiation with the dose of 15 Gy, and progressed slowly to the advance stage of cataract; while, for the higher dose (25 Gy), the opacity of lens appeared much earlier, and progressed more rapidly to mature stage of cataract within 1 month. At the end of the observation (90 days post-irradiation), almost all lenses became complete opacity with the higher dose (25 Gy). The degree of lens opacity was rated accordingly. The lens MDA level was increased, and SOD and GPx activities were decreased with a dose-dependent manner post-irradiation. The αB-crystallin protein level was decreased dose-dependently at the end point of observation. Oxidative events and αB-crystallin may play important roles in the pathogenesis of cataract in X-ray irradiated rat lens.

Aggregation of γ-crystallins associated with human cataracts via domain swapping at the C-terminal β-strands.

The prevalent eye disease age-onset cataract is associated with aggregation of human γD-crystallins, one of the longest-lived proteins. Identification of the γ-crystallin precursors to aggregates is crucial for developing strategies to prevent and reverse cataract. Our microseconds of atomistic molecular dynamics simulations uncover the molecular structure of the experimentally detected aggregation-prone folding intermediate species of monomeric native γD-crystallin with a largely folded C-terminal domain and a mostly unfolded N-terminal domain. About 30 residues including a, b, and c strands from the Greek Key motif 4 of the C-terminal domain experience strong solvent exposure of hydrophobic residues as well as partial unstructuring upon N-terminal domain unfolding. Those strands comprise the domain-domain interface crucial for unusually high stability of γD-crystallin. We further simulate the intermolecular linkage of these monomeric aggregation precursors, which reveals domain-swapped dimeric structures. In the simulated dimeric structures, the N-terminal domain of one monomer is frequently found in contact with residues 135-164 encompassing the a, b, and c strands of the Greek Key motif 4 of the second molecule. The present results suggest that γD-crystallin may polymerize through successive domain swapping of those three C-terminal β-strands leading to age-onset cataract, as an evolutionary cost of its very high stability. Alanine substitutions of the hydrophobic residues in those aggregation-prone β-strands, such as L145 and M147, hinder domain swapping as a pathway toward dimerization. These findings thus provide critical molecular insights onto the initial stages of age-onset cataract, which is important for understanding protein aggregation diseases.

Postoperative glaucoma in the Labrador Retriever: incidence, risk factors, and visual outcome following routine phacoemulsification

To evaluate the incidence and risk factors associated with development of postoperative glaucoma in the Labrador Retriever following routine phacoemulsification. Medical records from Labradors and a randomly selected population of non-Labradors were retrospectively evaluated. Signalment, diabetic status, cataract stage, gonioscopic findings, presence of preoperative lens-induced uveitis, development of postoperative hypertension (POH), postoperative glaucoma and postoperative visual status were recorded for each patient. Survival curves were developed using the Cox proportional hazards model. Forty-two Labradors (66 eyes) and 199 non-Labradors (314 eyes) were included. The incidence of POH was significantly higher in Labradors (33%) than non-Labradors (18%). Labradors were at significantly increased risk of postoperative glaucoma and blindness compared to non-Labradors. Estimated probabilities of postoperative glaucoma in Labradors were 23%, 25%, 30% and 35% at weeks 4, 26, 52 and 104, respectively, compared with 5%, 6%, 7% and 9% at weeks 4, 26, 52 and 104, respectively, in non-Labradors. Estimated probabilities of postoperative blindness in Labradors were 5%, 9%, 15% and 27% at weeks 4, 26, 52 and 104, respectively, compared with 2%, 3%, 5% and 10% at weeks 4, 26, 52 and 104, respectively, in non-Labradors. Risk factors for the development of glaucoma in Labradors included increasing age and development of POH. No statistically significant risk factors for the development of glaucoma were identified in non-Labradors. Labradors are at increased risk of glaucoma and blindness following phacoemulsification compared with non-Labradors. POH and increasing age represent risk factors for the development of postoperative glaucoma in Labradors.

Postoperative complications and visual outcomes of phacoemulsification in 103 dogs (179 eyes): 2006–2008

To describe the postoperative complications and visual outcome after phacoemulsification in dogs and identify risk factors for complications. One hundred and three dogs (179 eyes) that had phacoemulsification with or without intraocular lens (IOL) placement including foldable acrylic IOLs between March 2006 and March 2008 at Purdue University Veterinary Teaching Hospital. Medical records were reviewed and occurrence and dates of postoperative complications were tabulated. Visual status at the final recheck during the study period was recorded. Additional information including signalment, diabetes mellitus status, operative complications and factors, presence of prior lens induced uveitis, preoperative retinopexy, and cataract stage was collected. The majority of eyes were functionally visual (148 eyes, 82.7%) at the end of the study period. Blindness was seen in 18 eyes (10.0%) with reduced vision in 13 eyes (7.3%) at the final recheck. Postoperative ocular hypertension (22.9%), corneal lipid opacity (19.0%), uveitis (16.2%), intraocular hemorrhage (12.3%), retinal detachment (8.4%), and glaucoma (6.7%) were the most common postoperative complications seen in eyes. The odds of blindness were significantly greater (OR = 290.44) in the eyes of Boston terriers compared with mixed breed dogs and with each year of increasing age (OR = 2.00). The prognosis for vision after phacoemulsification with injectable IOL placement is good. Boston terriers were at much higher risk for certain complications.

Expression of chloride channel protein-3 and aquaporin-1 in D-galactose cataractous rat lens

目的 研究大鼠半乳糖性白内障晶状体中氯离子通道蛋白-3 (CLC-3)和水通道蛋白-1 (AQP-1) 表达水平的变化,探讨CLC-3和AQP-1与白内障发病的关系.方法 健康清洁级Wistar大鼠88只随机分为空白对照组(8只)、生理盐水组(40只)和半乳糖性白内障模型组(Gal组)(40 只).生理盐水组和Gal组根据处理时间不同各亚分为5个亚组,每个亚组8只大鼠.Gal组单侧眼球后注射D-半乳糖生理盐水注射液,生理盐水组同期单侧眼球后注射等体积无菌生理盐水,每日裂隙灯下观察大鼠晶状体混浊的动态变化,并参照Kador等的分级标准分期记录.分别于第1次给药后第3、7、14、21、30天在全身麻醉下处死各组实验大鼠,摘出晶状体,应用实时荧光定量PCR法检测各组晶状体中CLC-3mRNA和AQP-1mRNA含量的变化.结果 透明晶状体和半乳糖性白内障晶状体中均有CLC-3mRNA和AQP-1mRNA的表达;生理盐水组各时间点CLC-3mRNA和AQP-1mRNA的表达差异无统计学意义(P＞0.05);Gal组于3、7、14d时CLC-3mRNA表达逐渐增高,均高于同期生理盐水组,到14d时约达正常水平的7倍,21d、30d时又有所下降,均低于同期生理盐水组(P＜0.01);各时间点晶状体CLC-3mRNA含量两两比较,差异均有统计学意义 (P＜0.01);模型组于3d时AQP-1mRNA表达已下降,与同期生理盐水组比较差异有统计学意义(P＜0.05),且随着白内障的进一步发展,AQP-1mRNA含量逐渐降低,均低于同期生理盐水组(P＜0.01);各时间点晶状体AQP-1mRNA含量两两比较,差异均有统计学意义 (P＜0.01).结论 晶状体中CLC-3和AQP-1表达的变化可能与白内障的发生发展有着密切的联系。