A multivariate analysis of the factors affecting the visual outcome and complications following scleral fixated intraocular lens implantation.

Cataract is the leading cause of reversible blindness throughout the world. Cataractogenesis can be due to old age, trauma, congenital, infectious and metabolic causes. It is estimated that in India alone 5.1 million people undergo cataract surgery every year. Following uneventful cataract surgery, intraocular lens is usually implanted in the capsular bag. Patients with inadequate capsular support following cataract surgery, trauma or collagen vascular diseases can be visually rehabilitated with aphakic spectacles, contact lenses, anterior chamber intraocular lenses, iris fixated lenses and scleral fixated intraocular lenses. These intraocular lenses can be implanted as a primary or as a secondary procedure. Since the discovery of the scleral fixated intraocular lenses by Parry1 in 1950, various changes and various techniques have emerged for its fixation. Placement of the IOL in the posterior chamber, reduces the risk of bullous keratopathy, damage to anterior chamber angle structures, damage to corneal endothelium, pupillary block glaucoma, and pseudophakodonesis .In addition positioning the lens closer to the rotational centre of the eye, may reduce the centrifugal forces on the lens and stabilize the ocular contents, decrease the magnification associated with contact lenses, optical aberrations associated with aphakic spectacles and imparts superior optical properties to the eye. In our study, males are predominantly affected. The age group 45-75 years formed the core group to get operated. Majority of the patients presented with post surgical aphakia. The statistically significant factors associated with poor visual outcome are preoperative factors like chronic uveitis and trauma, intraoperative factors like prolonged duration of surgery and post-operative complications like iritis and striate keratopathy. Results in this study reveal that the visual outcome following the secondary SFIOL implantation is better than primary SFIOL implantation which can be attributed to the increased rate of inflammation in the primary procedure. The success rate of the surgery was 62% .The post operative refraction is mostly towards myopic side in this study. The final visual outcome depends on the preoperative, intraoperative and postoperative factors. So emphasis must be laid on thorough preoperative evaluation of the patient, meticulous surgical technique and treatment of the postoperative complications

Two Plant Viral Suppressors of Silencing Require the Ethylene-Inducible Host Transcription Factor RAV2 to Block RNA Silencing

RNA silencing is a highly conserved pathway in the network of interconnected defense responses that are activated during viral infection. As a counter-defense, many plant viruses encode proteins that block silencing, often also interfering with endogenous small RNA pathways. However, the mechanism of action of viral suppressors is not well understood and the role of host factors in the process is just beginning to emerge. Here we report that the ethylene-inducible transcription factor RAV2 is required for suppression of RNA silencing by two unrelated plant viral proteins, potyvirus HC-Pro and carmovirus P38. Using a hairpin transgene silencing system, we find that both viral suppressors require RAV2 to block the activity of primary siRNAs, whereas suppression of transitive silencing is RAV2-independent. RAV2 is also required for many HC-Pro-mediated morphological anomalies in transgenic plants, but not for the associated defects in the microRNA pathway. Whole genome tiling microarray experiments demonstrate that expression of genes known to be required for silencing is unchanged in HC-Pro plants, whereas a striking number of genes involved in other biotic and abiotic stress responses are induced, many in a RAV2-dependent manner. Among the genes that require RAV2 for induction by HC-Pro are FRY1 and CML38, genes implicated as endogenous suppressors of silencing. These findings raise the intriguing possibility that HC-Pro-suppression of silencing is not caused by decreased expression of genes that are required for silencing, but instead, by induction of stress and defense responses, some components of which interfere with antiviral silencing. Furthermore, the observation that two unrelated viral suppressors require the activity of the same factor to block silencing suggests that RAV2 represents a control point that can be readily subverted by viruses to block antiviral silencing

Bio-nanotechnology application in wastewater treatment

The nanoparticles have received high interest in the field of medicine and water purification, however, the nanomaterials produced by chemical and physical methods are considered hazardous, expensive, and leave behind harmful substances to the environment. This chapter aimed to focus on green-synthesized nanoparticles and their medical applications. Moreover, the chapter highlighted the applicability of the metallic nanoparticles (MNPs) in the inactivation of microbial cells due to their high surface and small particle size. Modifying nanomaterials produced by green-methods is safe, inexpensive, and easy. Therefore, the control and modification of nanoparticles and their properties were also discussed

An efficient Foxtail mosaic virus vector system with reduced environmental risk

<p>Abstract</p> <p>Background</p> <p>Plant viral vectors offer high-yield expression of pharmaceutical and commercially important proteins with a minimum of cost and preparation time. The use of <it>Agrobacterium tumefaciens </it>has been introduced to deliver the viral vector as a transgene to each plant cell via a simple, nonsterile infiltration technique called "agroinoculation". With agroinoculation, a full length, systemically moving virus is no longer necessary for excellent protein yield, since the viral transgene is transcribed and replicates in every infiltrated cell. Viral genes may therefore be deleted to decrease the potential for accidental spread and persistence of the viral vector in the environment.</p> <p>Results</p> <p>In this study, both the coat protein (CP) and triple gene block (TGB) genetic segments were eliminated from <it>Foxtail mosaic virus </it>to create the "FECT" vector series, comprising a deletion of 29% of the genome. This viral vector is highly crippled and expresses little or no marker gene within the inoculated leaf. However, when co-agroinoculated with a silencing suppressor (p19 or HcPro), FECT expressed GFP at 40% total soluble protein in the tobacco host, <it>Nicotiana benthamiana</it>. The modified FoMV vector retained the full-length replicase ORF, the TGB1 subgenomic RNA leader sequence and either 0, 22 or 40 bases of TGB1 ORF (in vectors FECT0, FECT22 and FECT40, respectively). As well as <it>N. benthamiana</it>, infection of legumes was demonstrated. Despite many attempts, expression of GFP via syringe agroinoculation of various grass species was very low, reflecting the low <it>Agrobacterium</it>-mediated transformation rate of monocots.</p> <p>Conclusions</p> <p>The FECT/40 vector expresses foreign genes at a very high level, and yet has a greatly reduced biohazard potential. It can form no virions and can effectively replicate only in a plant with suppressed silencing.</p

Antiviral Silencing and Suppression of Gene Silencing in Plants

RNA silencing is an evolutionary conserved sequence-specific gene inactivation mechanism that contributes to the control of development, maintains heterochromatin, acts in stress responses, DNA repair and defends against invading nucleic acids like transposons and viruses. In plants RNA silencing functions as one of the main immune systems. RNA silencing process involves the small RNAs and trans factor components like Dicers, Argonautes and RNA-dependent RNA poly- merases. To deal with host antiviral silencing responses viruses evolved mecha- nisms to avoid or counteract this, most notably through expression of viral suppressors of RNA silencing. Due to the overlap between endogenous and antiviral silencing pathways while blocking antiviral pathways viruses also impact endogenous silencing processes. Here we provide an overview of antiviral silencing pathway, host factors implicated in it and the crosstalk between antiviral and endogenous branches of silencing. We summarize the current status of knowledge about the viral counter-defense strategies acting at various steps during virus infection in plants with the focus on representative, well studied silencing suppres- sor proteins. Finally we discuss future challenges of the antiviral silencing and counter-defense research field

Plant viral suppressors of post-transcriptional silencing do not suppress transcriptional silencing

42 ref. doi: 10.1046/j.1365-313x.2000.007.xInternational audienc