Objective evaluation of the changes in the crystalline lens during accommodation in young and presbyopic populations using Pentacam HR system.

AIM: To quantify the changes in the lens profile with accommodation in different age groups. METHODS: The Pentacam HR system was used to obtain the images of the anterior eye segment from 23 young and 15 presbyopic emmetropic subjects in unaccommodated (with an accommodation stimulus of 0.0D) and accommodated (with an accommodation stimulus of 5.0D for the young group and 1.0D for the presbyopic group) states. The phakic crystalline lens shape, including curvature of crystalline lens and central lens thickness (CLT), and the measurements of anterior segment length (ASL), central anterior chamber depth (CACD) were investigated. The anterior chamber volume (ACV) was also measured. RESULTS: The reduction of CACD and ACV were significant in both groups after accommodation stimulus. From the profile of anterior eye segment, a significant decrease in anterior crystalline lens radii of curvature (-2.52mm) and a mean increase in CLT (0.222mm) and ASL (0.108mm) were found in the young group with an accommodation stimulus of 5.0D. However, no statistically significant changes of CLT, ASL, or crystalline lens radii of curvature were found in the presbyopic group. CONCLUSION: Our data showed that the shallowing of anterior chamber during accommodation was caused by the forward bulging of the anterior lens surface, rather than by anterior shifting of lens position in either young or presbyopic subjects.

[Comparative studies of wavefront aberration and contrast sensitivity after phacoemulsification and intraocular lens implantation].

OBJECTIVE: To study the difference of the contrast sensitivity and wavefront aberration of two eyes who undergone phacoemulsification and intraocular transplantation respectively. METHODS: Sixty-three patients with cataract were included in the study. With the consent of the patients, one eye was implanted SA60AT intraocular lens and another eye was implanted Tennis Z9001 intraocular lens after phacoemulsification. One and three months post-surgery, the best corrected visual acuity was recorded by computer and comprehensive optometry. Contrast sensitivity was analyzed by CSV-1000. The corneal aberration was measured by Option Keratron Scout. The whole ocular aberration was evaluated by Allegretto Waver Analyzer at pupillary diameter 4 mm and 6 mm. RESULTS: The best corrected visual acuity and the corneal spherical aberration, corneal coma aberration and RMS had no significant difference between the two groups. After one and three months, the contrast sensitivity of 3, 6, 12, 18c/d had statistic significance between the eye with and without glare through univariate split-plot analysis. The Z9001 contrast sensitivity value was much higher than the SA60AT groups. The results of Zernike polynomials C12, RMS4 and RMSh had statistic significance between the two groups through T-test. The Z9001 group value was much lower than the SA60AT groups. CONCLUSIONS: The Z9001 intraocular lens transplantation can reduce total ocular aberration, special the spherical aberration and improve visual acuity.

[Spontaneous response and mechanism to ischemia in diabetic mouse].

OBJECTIVE: To investigate the spontaneous response and its mechanism of type 2 diabetes mouse to surgical induced hind limb ischemia. METHODS: Forty mice were randomly divided into two groups, one was fed with normal chow, and another was fed with high fat diet. Twelve weeks later, mice were surgical induced to hind limb ischemia. Blood flow was monitored. Four weeks later, mice were sacrificed and muscle tissues were harvested for histological detection, Western Blot, ELISA and RT-PCR examination respectively. RESULTS: Spontaneous restoration of blood flow was significantly slow down in type 2 diabetic mice with lower level of vascular density in ischemic muscles. VEGF signaling pathway was impaired although the VEGF levels were increased in diabetes. CONCLUSIONS: The spontaneous response to ischemia was attenuated with an abnormal reaction of VEGF signaling pathway in the setting of type 2 diabetes mellitus.

[Effects of human retinal glial cells under hypoxic conditions on circulating endothelial progenitor cells].

OBJECTIVE: The specific signaling events by which circulating endothelial progenitor cells (EPCs) responding to alterations of the retinal vasculature induced by hypoxia are not yet completely understood. Our goal was to generate a suitable experimental model for the identification of such factors as well as the effects of these factors on the EPCs. METHODS: Primary cultures of human retinal glial cells were incubated under hypoxic or normoxic conditions. Effects of hypoxia were confirmed by analysis of HIF-lalpha and VEGF expression. Circulating EPCs (CD34 +, CD133+ double-positive cells) were isolated by FACS Vantage from the human periphery blood. EPCs were treated with conditioned media from retinal glial cells incubated under either hypoxic or normoxic conditions. Effects of conditioned media on the proliferation and differentiation of EPCs were evaluated. RESULTS: Incubation of human retinal glial cells at low oxygen concentration for 24 hours lead to HIF-lalpha expression and a significant increase of VEGF released to the media[ (319. 16 +/-34. 12) pg/ml versus (220. 28+/-24. 33) pg/ml] as compared to the control cultures incubated at normoxic conditions (P <0. 01). Treatment of EPCs with conditioned medium from retinal glial cells incubated at low oxygen concentration resulted in an increase of proliferative activity (day 3: 0. 83+/-0. 10 versus 0. 61+/-0. 22,P <0. 05; day 7: 1. 53+/-0. 21 versus 0. 88+/-0. 25, P <0. 05) and presence of differentiated endothelial cells as compared to cells cultured with conditioned media from normoxic cultures. CONCLUSIONS: Conditioned media from retinal glial cells contain factors capable of activating the proliferation and differentiation of circulating EPCs. Analysis of the effects of conditioned medium from neuronal glial cells incubated under hypoxic conditions on circulating human EPCs might be useful in providing an effective experimental method for the identification of the specific signaling molecules involved in the activation of circulating EPCs for the regeneration of retinal blood vessels.

[Identification of rabbit lens proteins by two-dimensional gel electrophoreses and mass spectrometry].

OBJECTIVE: To study the role of lens proteomics using two-dimensional electrophoresis (2-DE) and mass spectrometry in order to exploring novel effective ways for cataract prevention and therapy. METHODS: The proteins of the three-month-year old rabbit lens were separated using immobilized pH gradients 2-DE. Image analysis was carried out using Image Master 2D Elite 3.01 software package. Most of the crystallines was identified by matrix assisted laser adsorption/ionization-time of-flight-mass spectrometry (MALDI-TOF-MS). RESULTS: The maps of 2-DE showed that lens proteins were in the section of pH 5 - 9 and the relative molecular weight was 14,000 - 94,000, while relative molecular weight of more abundant crystalline was localized at 14,000 - 40,000. About 180 protein spots were detected with the similar PI, molecular weight and quantity of each spot could be acquired by image analysis software. Sixteen crystallines were identified using MALDI-TOF-MS. CONCLUSION: Proteomic analysis of lens can be accomplished and the proteins can be well separated and analyzed using 2-DE and mass spectrometry. This technique offers a new avenue for analyses of lens proteins and to assess their differential expression in cataract, and may thus provide a novel approach to cataract prevention and therapy.

[Disorders of the blood-aqueous barrier after phacoemulsification].

OBJECTIVE: To determine the status of blood-aqueous barrier after small incision phacoemulsification with implantation of foldable intraocular lens. METHODS: The blood-aqueous barrier status in 64 eyes of 60 patients who underwent cataract surgery was examined using a laser flare cell meter. The protein level of anterior chamber aqueous humor was evaluated by measurement of the flare value preoperatively and postoperatively. RESULTS: The mean preoperative flare intensity was (6.94 +/- 0.34) photon counts/ms, which increased to (26.27 +/- 1.37), (13.96 +/- 1.05), (9.07 +/- 0.43) and (7.16 +/- 0.27) photon counts/ms on days 1, 7, 30 and 90 after the surgery, respectively. Significantly statistical differences on flare values were found between preoperative data and those on days 1, 7 and 30 after surgery. The blood-aqueous barrier was recovered on day 90 postoperatively. The variables such as age, gender, eye (left/right) had no influence on the flare value. Patients with iris prolapse had a higher flare value at day 1 and day 7 after the surgery. CONCLUSIONS: Blood-aqueous barrier after phacoemulsification with implantation of intraocular lens can be measured quantitatively by the laser flare cell meter. The blood-aqueous barrier disorders can be recovered shortly after phacoemulsification.

[Expression of Pax-6 homeobox gene in lens epithelial cells in vitro].

OBJECTIVE: To detect the gene expression of Pax-6 in cultured lens epithelial cells (LECs) of mouse in vitro in order to study the gene factor that maintains the LECs characteristics. METHODS: Cultured the LECs (passage 1 to 3) were used in the study, the expression of Pax-6 gene in LECs was demonstrated by reverse transcriptase polymerase chain reaction (RT-PCR), immunohistochemical staining and Western blot. RESULTS: The mRNA of Pax-6 gene was positive in primary culture, the first and second passage of LECs using RT-PCR. The protein of Pax-6 gene was also positive in Western blot and immunohistochemical staining, but it was weak positive in the third passage of LECs and none in all passages of negative control groups. CONCLUSION: The LECs are positive for the gene of Pax-6. The normal expression of Pax-6 gene is vital for maintaining the LECs characteristics.