Goat eye integrated with soap pellet as cataractous lens for phaco emulsification training: A thread to catch up the learning curve during pandemic.
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ABSTRACT:
SUBMITTER: Ravichnadran S
PROVIDER: S-EPMC8186643 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:A proteolytic enzyme was isolated from human senile cataractous lens by anion-exchange and gel-filtration chromatography. Sedimentation and zone-electrophoretic experiments indicated a high degree of homogeneity for the enzyme. A molecular weight of 27000 was calculated from measurements of sedimentation velocity and diffusion coefficient. Chelating agents decreased activity which could be restored by addition of certain bivalent metal ions. Di-isopropyl phosphorofluoridate and phenylmethanesulphonyl fluoride inhibit the proteolytic activities. Optimum rates of hydrolysis were observed at pH5.2.
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Project description:A relatively simple and inexpensive technique to train surgeons in phacoemulsification using a goat's eye integrated with a human cataractous nucleus is described. The goat's eye is placed on a bed of cotton within the lumen of a cylindrical container. This is then mounted on a rectangular thermocol so that the limbus is presented at the surgical field. After making a clear corneal entry with a keratome, the trainer makes a 5-5.5 mm continuous curvilinear capsulorhexis in the anterior lens capsule, creates a crater of adequate depth in the cortex and inserts the human nucleus within this crater in the goat's capsular bag. The surgical wound is sutured, and the goat's eye is ready for training. Creating the capsulorhexis with precision and making the crater of adequate depth to snugly accommodate the human nucleus are the most important steps to prevent excessive wobbling of the nucleus while training.
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Project description:PurposeEstrogen receptor alpha (ERalpha) expression has previously been evaluated in lens epithelial cells (LEC). However, its function in the lens has not been determined. One potential function may be its interaction with the catalytic subunit of telomerase (TERT), which is present in normal LEC and higher in LEC that have undergone epithelial to mesenchymal transition (EMT). ERalpha is known to play a role in EMT, a process that may also involve TERT.MethodsA commercially available transcription factor array was used to evaluate potential interactions between TERT and other proteins in normal and cataractous LEC. Based on these findings, ERalpha protein and mRNA expressions were measured using western blot analysis, immunohistochemical staining, and quantitative reverse transcription polymerase chain reaction (RT-PCR). Co-immunoprecipitation assays were used to evaluate the interaction of TERT with ERalpha as well as their phosphorylation in normal and cataractous LEC.ResultsThe transcription factor array suggested that TERT interacted with ERalpha via the estrogen response element (ERE) in cataractous LEC but not in normal LEC. Expression of ERalpha protein and mRNA increased in cataractous LEC compared with normal LEC. Co-immunoprecipitation assays confirmed the interaction of TERT with ERalpha in cataractous LEC while no interaction was found in normal LEC. LEC that have undergone EMT, e.g., cataracts, are rapidly proliferating and migrating along the posterior lens capsule.ConclusionsERalpha is known to play a role in EMT, and our data suggests that TERT and phosphorylated protein kinase B (pAkt) may be involved in the regulation of this process in cataractous LEC.
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Project description:Use of the phaco tip technique for lens cleavage and removal does not require manual hydrodissection using a syringe and cannula, or cortical removal using an irrigation/aspiration tip. The phaco tip is the only surgical instrument required for this technique. Its advantages include maintaining a stable intraocular pressure during cortical cleaving hydrodissection and lens removal, which includes the cortex.
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Project description:Femtosecond laser-assisted cataract surgery was performed in a case of posttraumatic cataract with six clock hours subluxation and vitreous in the anterior chamber (AC). Femtosecond laser pretreatment allowed a closed-chamber creation of corneal incisions, capsulotomy, and lens fragmentation with minimal sudden lens-diaphragm movements and zonular stress. Integrated imaging systems allowed customization of the size and position of capsulotomy and nuclear fragmentation, based on the extent and site of subluxation. Presence of vitreous in AC did not hamper femtosecond laser application. Triamcinolone-assisted vitrectomy was performed before phacoemulsification and after implanting the intraocular lens (IOL). Postoperative uncorrected visual acuity was 20/20 with a stable IOL.
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Project description:Recent evidence supports a role for microRNAs (miRNAs) in regulating gene expression, and alterations in gene expression are known to affect cells involved in the development of ageing disorders. Using developing rat lens epithelial cells (LECs), we profiled the expression of miRNAs by a microarray-based approach. Few gene expression changes known to be involved in pathogenesis or cytoprotection were uniquely influenced by miRNA expression. Most miRNAs increased or decreased in abundance (let 7b, let 7c, miR29a, miR29c, miR126 and miR551b) in LECs/lenses during late embryonic and post-natal development and in cataract. Among them, miR29a, miR29c and miR126 were dramatically decreased in cataractous LECs from Shumiya Cataract Rats (SCRs). Specifically, the cytoskeleton remodelling genes tropomyosin (Tm) 1? and 2?, which have been implicated in the initiation of pathophysiology, were targets of miR29c and were over-stimulated as demonstrated by inhibitor experiments. In transfection experiments, increasing the level of miR29c caused a corresponding decrease in the expression of Tm1? and 2?, suggesting that miR29c may regulate the translation of Tm1? and 2?. 3'UTR luciferase activity of Tm1?, not 2?, was significantly decreased in miR29c-transfected mouse LECs. These findings demonstrate changes in miRNAs expression, and target molecules have potential as diagnostic indicators of ageing and as a foundation of miR-based therapeutics for age-related diseases.
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Project description:PURPOSE: Post-translational modification (PTM) of lens proteins is believed to play various roles in age-related lens function and development. Among the different types of PTM, phosphorylation is most noteworthy to play a major role in the regulation of various biosignaling pathways in relation to metabolic processes and cellular functions. The present study reported the quantitative analysis of the in vivo phosphoproteomics profiles of human normal and cataractous lenses with the aim of identifying specific phosphorylation sites which may provide insights into the physiologic significance of phosphorylation in relation to cataract formation. METHODS: To improve detection sensitivity of low abundant proteins, we first adopted SDS-gel electrophoresis fractionation of lens extracts to identify and compare the protein compositions between normal and cataractous lenses, followed by tryptic digestion, enrichment of phosphopeptides by immobilized metal affinity chromatography (IMAC) and nano-liquid chromatography coupled tandem mass spectrometry (nanoLC-MS/MS) analysis. RESULTS: By comprehensively screening of the phosphoproteome in normal and cataractous lenses, we identified 32 phosphoproteins and 73 phosphorylated sites. The most abundantly phosphorylated proteins are two subunits of ?-crystallin, i.e., ?B1-crystallin (12%) and ?B2-crystallin (12%). Moreover, serine was found to be the most abundantly phosphorylated residue (72%) in comparison with threonine (24%) and tyrosine (4%) in the lens phosphoproteome. The quantitative analysis revealed significant and distinct changes of 19 phosphoproteins corresponding to 28 phosphorylated sites between these two types of human lenses, including 20 newly discovered novel phosphorylation sites on lens proteins. CONCLUSIONS: The shotgun phosphoproteomics approach to characterize protein phosphorylation may be adapted and extended to the comprehensive analysis of other types of post-translational modification of lens proteins in vivo. The identification of these novel phosphorylation sites in lens proteins that showed differential expression in the cataractous lens may bear some unknown physiologic significance and provide insights into phosphorylation-related human eye diseases, which warrant further investigation in the future.
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Project description:Age-related cataractogenesis is associated with disulfide-linked high molecular weight (HMW) crystallin aggregates. We recently found that the lens crystallin disulfidome was evolutionarily conserved in human and glutathione-depleted mouse (LEGSKO) cataracts and that it could be mimicked by oxidation in vitro (Mol. Cell Proteomics, 14, 3211-23 (2015)). To obtain a comprehensive blueprint of the oxidized key regulatory and cytoskeletal proteins underlying cataractogenesis, we have now used the same approach to determine, in the same specimens, all the disulfide-forming noncrystallin proteins identified by ICAT proteomics. Seventy-four, 50, and 54 disulfide-forming proteins were identified in the human and mouse cataracts and the in vitro oxidation model, respectively, of which 17 were common to all three groups. Enzymes with oxidized cysteine at critical sites include GAPDH (hGAPDH, Cys247), glutathione synthase (hGSS, Cys294), aldehyde dehydrogenase (hALDH1A1, Cys126 and Cys186), sorbitol dehydrogenase (hSORD, Cys140, Cys165, and Cys179), and PARK7 (hPARK7, Cys46 and Cys53). Extensive oxidation was also present in lens-specific intermediate filament proteins, such as BFSP1 and BFSP12 (hBFSP1 and hBFSP12, Cys167, Cys65, and Cys326), vimentin (mVim, Cys328), and cytokeratins, as well as microfilament and microtubule filament proteins, such as tubulin and actins. While the biological impact of these modifications for lens physiology remains to be determined, many of these oxidation sites have already been associated with either impaired metabolism or cytoskeletal architecture, strongly suggesting that they have a pathogenic role in cataractogenesis. By extrapolation, these findings may be of broader significance for age- and disease-related dysfunctions associated with oxidant stress.
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Project description:Cataract is the leading cause of visual impairment globally. Racemization of lens proteins may contribute to cataract formation in aging individuals. As a special type of age-related cataract (ARC), diabetic cataract (DC) is characterized by the early onset of cortical opacification and finally developed into a mixed type of cortical and nuclear opacification. We compared racemization of Asp 58 residue, a hotspot position in αA-crystallin, from the cortex and nucleus of diabetic and age-matched senile cataractous lenses, by identifying L-Asp/L-isoAsp/D-Asp/D-isoAsp by mass spectrometry. Compared to nondiabetic cataractous lenses, DC lenses showed a significantly increased cortex/nucleus ratio of D-Asp 58, which originated primarily from an increased percentage of D-Asp 58 in the lens cortex of DC. Moreover, patients diagnosed with diabetes for over 10 years showed a lower cortex/nucleus ratio of D-isoAsp 58 in the lens compared with those who had a shorter duration of diabetes, which originated mainly from an increased percentage of D-isoAsp 58 in the lens nucleus of DC with increasing time of hyperglycemia. Further analysis confirmed decreased protein solubility in diabetic cataractous lenses. The different racemization pattern in DC may be distinguished from ARC and influence its phenotype over the protracted duration of diabetes.
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Project description:The Shumiya cataract rat (SCR) is a model for hereditary cataract. Two-thirds of these rats develop lens opacity within 10-11 weeks. Onset of cataract is attributed to the synergetic effect of lanosterol synthase (Lss) and farnesyl-diphosphate farnesyltransferase 1 (Fdft1) mutant alleles that lead to cholesterol deficiency in the lenses, which in turn adversely affects lens biology including the growth and differentiation of lens epithelial cells (LECs). Nevertheless, the molecular events and changes in gene expression associated with the onset of lens opacity in SCR are poorly understood. In the present study, a microarray-based approach was employed to analyze comparative gene expression changes in LECs isolated from the precataractous and cataractous stages of lenses of 5-week-old SCRs. The changes in gene expression observed in microarray results in the LECs were further validated using real-time reverse transcribed quantitative PCR (RT-qPCR) in 5-, 8-, and 10-week-old SCRs. A mild posterior and cortical opacity was observed in 5-week-old rats. Expressions of approximately 100 genes, including the major intrinsic protein of the lens fiber (Mip and Aquaporin 0), deoxyribonuclease II beta (Dnase2B), heat shock protein B1 (HspB1), and crystallin ? (?Cry) B, C, and F, were found to be significantly downregulated (0.07-0.5-fold) in rat LECs derived from cataract lenses compared to that in noncataractous lenses (control). Thus, our study was aimed at identifying the gene expression patterns during cataract formation in SCRs, which may be responsible for cataractogenesis in SCR. We proposed that cataracts in SCR are associated with reduced expression of these lens genes that have been reported to be related with lens fiber differentiation. Our findings may have wider implications in understanding the effect of cholesterol deficiency and the role of cholesterol-lowering therapeutics on cataractogenesis.
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