Different experimental approaches in modelling cataractogenesis: An overview of selenite-induced nuclear cataract in rats

Cataract, the opacification of eye lens, is the leading cause of blindness worldwide. At present, the only remedy is surgical removal of the cataractous lens and substitution with a lens made of synthetic polymers. However, besides significant costs of operation and possible complications, an artificial lens just does not have the overall optical qualities of a normal one. Hence it remains a significant public health problem, and biochemical solutions or pharmacological interventions that will maintain the transparency of the lens are highly required. Naturally, there is a persistent demand for suitable biological models. The ocular lens would appear to be an ideal organ for maintaining culture conditions because of lacking blood vessels and nerves. The lens in vivo obtains its nutrients and eliminates waste products via diffusion with the surrounding fluids. Lens opacification observed in vivo can be mimicked in vitro by addition of the cataractogenic agent sodium selenite (Na2SeO3) to the culture medium. Moreover, since an overdose of sodium selenite induces also cataract in young rats, it became an extremely rapid and convenient model of nuclear cataract in vivo. The main focus of this review will be on selenium (Se) and its salt sodium selenite, their toxicological characteristics and safety data in relevance of modelling cataractogenesis, either under in vivo or in vitro conditions. The studies revealing the mechanisms of lens opacification induced by selenite are highlighted, the representatives from screening for potential anti-cataract agents are listed

Diet and prey selection of pikeperch (Sander lucioperca Linnaeus, 1758) population in Lake Eğirdir (Turkey)

The diet and prey selection of pikeperch (Sander lucioperca L., 1758) were assessed by determining the frequency of occurrence, numeric and weight percentages, and the index of relative importance (IRI%) between January 2010 and December 2010 in Lake Eğirdir, Turkey. Pearre’s index was used to estimate diet selectivity, while the Schoener Overlap Index was utilized to compare diets. The stomach contents of 241 S. lucioperca were analyzed. Pikeperch diet included prey fish, insects and other organisms. The diet was predominantly fish, consisting of Atherina boyeri, Knipowitschia caucasica, Aphanius anatoliae, Seminemacheilus ispartensis and Carassius gibelio. A. boyeri was the most abundant prey fish in the lake; it was a positively selected food item (V= 0.130, X2= 3.359, p> 0.05) and was not statistically significant. C. gibelio also inhabits the lake, but was not preferred by pikeperch (V=0.134, X2= 3.582, p> 0.05). In addition, A. anatoliae (V=-0.223, X2=9.977, p<0.01) and Chironomus sp., (V= -0.297, X2= 17.665, p<0.01) were negatively chosen by pikeperch despite their high abundance in the lake. Stomach fullness was highest in January, while feeding density was lowest in November and >50 cm in length pikeperch. Cannibalism was not evident during a decade, due to there being enough food for pikeperch in the lake

Evaluation of Aqueous Endocan and Endostatin Levels in Patients With Pseudoexfoliation Syndrome.

PURPOSE: The purpose of the present study was to evaluate the aqueous humor endocan and endostatin levels in patients with pseudoexfoliation (PEX) syndrome and to compare the results with healthy individuals. MATERIALS AND METHODS: Twenty nine cataract patients with PEX syndrome (PEX group) and 32 cataract patients without PEX syndrome (control group) were enrolled in the study. Endocan and endostatin were measured in the aqueous humor of the PEX and control groups by enzyme-linked immunosorbent assay. RESULTS: There was no difference between the PEX and control groups in terms of age (P=0.721) and sex (P=0.902). The aqueous levels of endocan in patients with PEX (26.39±5.80 pg/mL) was significantly higher than in the control group (11.42±2.44 pg/mL) (P=0.039). The aqueous levels of endostatin was 12.00±1.35 ng/mL in the PEX group and 14.22±3.31 ng/mL in the control group, however, the difference was not statistically significant (P=0.41). CONCLUSIONS: The findings of the present study could suggest that the increased levels of aqueous endocan may be related to pathogenesis of PEX. However, levels of aqueous endostatin did not show any significant difference in PEX

Repeatability and reproducibility of Galilei measurements in normal keratoconic and postrefractive corneas.

OBJECTIVE: To assess the repeatability and reproducibility of the anterior segment measurements performed with a dual Scheimpflug analyzer (Galilei) in normal, keratoconic and post-refractive surgery corneas. METHODS: To evaluate the repeatability, two additional measurements were performed by the first examiner. To assess reproducibility, this was later followed by a single reading by the second examiner. The following parameters were recorded and evaluated in this study; central corneal thickness (CCT), thinnest corneal thickness (TCT), mean total corneal power (TCP) in central (0-4mm), mean posterior corneal power (PCP) in central (0.5-2mm), anterior and posterior elevation (best fit sphere [BFS]) in central 8mm anterior and posterior eccentricity (ɛ(2)) in central 8mm. Repeatability and reproducibility for each corneal parameter was assessed using the Bland-Altman analysis. RESULTS: Each of the three groups was consisted of 20 subjects (totally 60 patients, 30 men and 30 women). The 95% LoA for repeatability was very small, indicating small discrepancies between measurements related to CCT. Acceptable repeatability was also achieved for the other parameters in each group. However, the 95% LoA for value TCP was larger in keratoconic eyes. The 95% LoA for reproducibility was also very small, and acceptable for all measured parameters in each group. In addition, the 95% LoA was larger for the measurement of CCT and TCT for postrefractive corneas. CONCLUSIONS: The anterior segment measurements provided by Galilei showed good repeatability and reproducibility for normal, keratoconic and postrefractive corneas

Relationship Between Subfoveal Choroidal Thickness, Ocular Pulse Amplitude, and Intraocular Pressure in Healthy Subjects.

PURPOSE: To investigate the correlation between subfoveal choroidal thickness (SFCT), ocular pulse amplitude (OPA), and intraocular pressure (IOP) in healthy individuals. METHODS: In total, 106 eyes of 106 healthy adult participants were included in this cross-sectional study. Spectral-domain optical coherence tomography was used to measure the SFCT. OPA and IOP were measured with the Pascal dynamic contour tonometer. The Pearson correlation test was performed to examine the relationship between SFCT, OPA, and IOP. RESULTS: When age, sex, and body mass index (BMI) were controlled separately, a weak correlation occurred between SFCT and OPA (age controlled, r=0.20; sex controlled, r=0.19; BMI controlled, r=0.13). SFCT and OPA were fairly correlated in older age (r=0.33, P=0.02) and low BMI (r=0.33, P=0.02). SFCT and IOP were not correlated statistically significantly (r=0.05, P=0.59). CONCLUSION: There is a weak correlation between SFCT and OPA in healthy individuals when age is controlled. The association becomes stronger in participants with low BMI. There is no relation between SFCT and IOP

Comparison of central corneal thickness, thinnest corneal thickness, anterior chamber depth, and simulated keratometry using galilei, Pentacam, and Sirius devices.

PURPOSE: The aim was to evaluate the agreement in the central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior chamber depth (ACD), and mean simulated keratometry (simK) measurements using Pentacam, Galilei, and Sirius Scheimpflug systems in normal eyes. METHODS: Anterior segment measurements were performed with Pentacam, Galilei, and Sirius devices in 32 healthy subjects. The right eye of each participant was selected. Measurements obtained with the 3 systems were compared using repeated-measures analysis of variance and Bonferroni multiple comparisons test. RESULTS: Analysis of variance determined a significant difference in the anterior segment measurements of CCT, TCT, ACD, and simK between the 3 devices (P < 0.001). Pairwise comparisons of CCT and TCT measurements were significantly different except for the comparison between Pentacam and Sirius. All pairwise comparisons for ACD were statistically significant. The pairwise comparison results for simK values showed that the Galilei and Sirius systems demonstrated better agreement with each other than with Pentacam. CONCLUSIONS: The results of this study suggest that the Pentacam, Galilei, and Sirius Scheimpflug systems should not be accepted as interchangeable for CCT, TCT, ACD, and simK in healthy subjects