Reetika Sharma

DNA integrity and semen quality in men with low seminal antioxidant levels

Accurate transmission of information coded in the sperm genome is vital to the pre- and post-natal development of the offspring. Recent advances in reproductive biology have proposed evaluation of sperm DNA integrity as an important assessment tool to infer the presence of DNA strand breaks, numerical abnormalities in sperm chromosome complement, and alterations in the epigenetic regulation of the paternal genome. Oxidative stress (OS), characterized by increased free radicals, may lead to the production of apurine sites, apyrimidine sites, oxidation of nucleotides of sperm genome. This study was performed to assess the impact of OS on DNA integrity in sperms. 52 infertile men [oligozoospermic-13, asthenozoospermic-15, teratozoospermic-19, oligoasthenoteratozoospermic-5] and 20 fertile controls were investigated for products of lipidperoxides as malondialdehyde; antioxidants such as superoxide dismutase, catalase and glutathione in seminal plasma by biochemical methods. DNA integrity of the sperms was analyzed by visual scoring method in which the comets were graded into 4 categories (A-D) on the basis of their tail length indicative of increasing levels of DNA damage. Significant increase in DNA damage (higher number of sperms in group D) in cases (oligozoospermic (O)-20%, asthenozoospermic (A)-24%, teratozoospermic (T)-28%, OAT-43%) as compared to controls (8%) was found. Increased malondialdehyde levels, abnormal sperm morphology and higher DNA damage were observed in the cases. The antioxidants superoxide dismutase, catalase and glutathione had a positive association with sperm count and motility while a negative association with the percentage of dead sperms and abnormal morphology was observed. This study highlights the influence of low antioxidants on sperm genome integrity and indicates sperm DNA integrity as a better and more reliable prognostic tool for infertility evaluation than simple quantitative and morphologic evaluation of spermatozoa.

Application of anterior segment optical coherence tomography in glaucoma.

Optical coherence tomography (OCT) is a cross-sectional, three-dimensional, high-resolution imaging modality that uses low coherence interferometry to achieve axial resolution in the range of 3-20 μm. Two OCT platforms have been developed: time domain (TD-OCT) and spectral (or Fourier) domain (SD/FD-OCT). Visante anterior segment OCT (Carl Zeiss Meditec) is a TD-OCT widely used for anterior segment imaging. The SD-OCT systems with both posterior and anterior segment imaging capabilities include the RTVue, iVue (Optovue), the Cirrus (Carl Zeiss Meditec), and the Spectralis (Heidelberg Engineering, Inc.). Each of the SD-OCTs has a wavelength in the range of 820-879 nm. Anterior segment OCT is a non-contact method providing high resolution tomographic cross-sectional imaging of anterior segment structures. Anterior segment OCT provides qualitative and quantitative assessment of the anterior segment structures important to the pathogenesis and the anatomical variations of glaucoma, and the approach to and success of treatment. We summarize the clinical applications of anterior segment OCT in glaucoma.

Test-retest variability of retinal nerve fiber layer thickness and macular ganglion cell-inner plexiform layer thickness measurements using spectral-domain optical coherence tomography.

Purpose:To evaluate the test-retest variability of spectral-domain optical coherence tomography (OCT) in measurement of retinal nerve fiber layer (RNFL) thickness and macular ganglion cell-inner plexiform layer (GCIPL) thickness. Methods:A total of 65 eyes of healthy subjects were enrolled in this observational cross-sectional study. RNFL thickness and GCIPL thickness were measured using the repeat scan optic cube and macular cube protocol using Cirrus HD-OCT (software version 6.0). A single operator obtained 3 measurements during 1 session to determine test-retest variability. Intrasession repeatability was defined by intraclass correlation, limits of agreement, and coefficient of variation. Results:The mean age of patients was 37.89±15.11 years (range, 10 to 70 y). The mean RNFL thickness readings as measured during 3 sessions were 93.89±9.73, 93.63±10.00, and 93.55±9.64 &mgr;m and average GCIPL thickness measurements were 82.90±4.61, 82.98±4.24, and 83.06±4.36 &mgr;m, respectively. Coefficient of variation was 1.2 for average RNFL thickness and 0.82 for average GCIPL thickness. The intraclass correlation coefficient showed a good correlation between repeat measurements for both average RNFL and GCC thicknesses (0.994 and 0.990, respectively). The limits of agreement (95% confidence interval) for the 3 sessions ranged from −3.61 to 4.13 &mgr;m for the average RNFL thickness and −2.55 to 2.40 &mgr;m for GCIPL thickness measurements. Conclusions:In healthy eyes, Cirrus HD-OCT shows excellent intrasession repeatability for RNFL and GCIPL thickness measurements.

Saccadic eye movements in Parkinson's disease.

This review focuses on saccadic eye movement research in Parkinsons disease (PD) patients. Results from various studies related to Parkinson disease and saccades have been discussed in terms of various saccadic parameters like latency, amplitude, velocity and gain. Neural circuitry of saccadic eye movements and cognitive processes and its relation with altered saccadic performance in Parkinson disease has been discussed here. This article also covers various research paradigms commonly used to study saccades. Effects of medication on saccadic parameters in PD patients have also been discussed along with the effects of deep brain stimulation of subthalamic nucleus on saccadic performance in PD patients. Literature review was done using online Pubmed search engine and National Medical Library.

A COMPREHENSIVE WORK UP FOR AN ASTHENOZOOSPERMIC MAN WITH REPEATED INTRACYTOPLASMIC SPERM INJECTION (ICSI) FAILURE

Infertility affects about 15–20% couples attempting pregnancy and in about half cases the problem lies in the male. Among the sperm parameters, linear progressive motility is one of the most important predictors of fertility potential. Though genetic and chromosomal abnormalities are important aetiological factors in the pathogenesis of male infertility, the mechanism involved in impaired sperm motility is poorly understood. Here we report mitochondrial DNA (mtDNA) mutations with increased seminal reactive oxygen species (ROS) levels and higher DNA fragmentation level in the sperm resulting in decreased ATP production which plays an important role in sperm motility defect. Thus it is important to understand the aetiology of asthenozoospermia and to distinguish if infertile men harbour nuclear or mtDNA mutation as they are very important prognostic markers. This case study also highlights that routine semen parameters are very modest predictors of fertility outcome but ROS estimation and DNA integrity analysis by Comet assay have better diagnostic and prognostic capabilities. Thus this study is a detailed and comprehensive workup of an infertile asthenozoospermic male.

CYP1B1: a unique gene with unique characteristics.

CYP1B1, a recently described dioxin inducible oxidoreductase, is a member of the cytochrome P450 superfamily involved in the metabolism of estradiol, retinol, benzo[a]pyrene, tamoxifen, melatonin, sterols etc. It plays important roles in numerous physiological processes and is expressed at mRNA level in many tissues and anatomical compartments. CYP1B1 has been implicated in scores of disorders. Analyses of the recent studies suggest that CYP1B1 can serve as a universal/ideal cancer marker and a candidate gene for predictive diagnosis. There is plethora of literature available about certain aspects of CYP1B1 that have not been interpreted, discussed and philosophized upon. The present analysis examines CYP1B1 as a peculiar gene with certain distinctive characteristics like the uniqueness in its chromosomal location, gene structure and organization, involvement in developmentally important disorders, tissue specific, not only expression, but splicing, potential as a universal cancer marker due to its involvement in key aspects of cellular metabolism, use in diagnosis and predictive diagnosis of various diseases and the importance and function of CYP1B1 mRNA in addition to the regular translation. Also CYP1B1 is very difficult to express in heterologous expression systems, thereby, halting its functional studies. Here we review and analyze these exceptional and startling characteristics of CYP1B1 with inputs from our own experiences in order to get a better insight into its molecular biology in health and disease. This may help to further understand the etiopathomechanistic aspects of CYP1B1 mediated diseases paving way for better research strategies and improved clinical management.

Clinical utility of anterior segment swept-source optical coherence tomography in glaucoma

Optical coherence tomography (OCT), a noninvasive imaging modality that uses low-coherence light to obtain a high-resolution cross-section of biological structures, has evolved dramatically over the years. The Swept-source OCT (SS-OCT) makes use of a single detector with a rapidly tunable laser as a light source. The Casia SS-1000 OCT is a Fourier-domain, SS-OCT designed specifically for imaging the anterior segment. This system achieves high resolution imaging of 10΅m (Axial) and 30΅m (Transverse) and high speed scanning of 30,000 A-scans per second. With a substantial improvement in scan speed, the anterior chamber angles can be imaged 360 degrees in 128 cross sections (each with 512 A-scans) in about 2.4 seconds. We summarize the clinical applications of anterior segment SS-OCT in Glaucoma. Literature search: We searched PubMed and included Medline using the phrases anterior segment optical coherence tomography in ophthalmology, swept-source OCT, use of AS-OCT in glaucoma, use of swept-source AS-OCT in glaucoma, quantitative assessment of angle, filtering bleb in AS-OCT, comparison of AS-OCT with gonioscopy and comparison of AS-OCT with UBM. Search was made for articles dating 1990 to August 2015.

Genetic, Biochemical and Clinical Insights into Primary Congenital Glaucoma

ABSTRACT Glaucoma is an irreversible form of optic neuropathy in which the optic nerve suffers damage in a characteristic manner with optic nerve cupping and retinal ganglion cell death. Primary congenital glaucoma (PCG) is an idiopathic irreversible childhood blinding disorder which manifests at birth or within the first year of life. PCG presents with a classical triad of symptoms (viz epiphora, photophobia and blepharospasm) though there are many additional symptoms, including large eye ball and hazy cornea. The only anatomical anomaly found in PCG is trabecular meshwork (TM) dysgenesis. PCG is an inheritable disease with established genetic etiology. It transmits through autosomal recessive mode. A number of cases are sporadic also. Mutations in many genes have been found to be causative in PCG and many are yet to be found. Mutations in cytochrome P4501B1 (CYP1B1) gene have been found to be the predominant cause of PCG. Other genes that have been implicated in PCG etiology are myocilin, Forkhead-related transcription factor C1 (FOXC1) and latent transforming growth factor beta-binding protein 2 (LTBP2). Mutations in these genes have been reported from many parts of the world. In addition to this, mitochondrial genome mutations are also thought to be involved in its pathogenesis. There appears to be some mechanism involving more than one genetic factor. In this review, we will discuss the various clinical, biochemical and genetic aspects of PCG. We emphasize that etiology of PCG does not lie in a single gene or genetic factor. Research needs to be oriented into a direction where gene-gene interactions, ocular embryology, ophthalmic metabolism and systemic oxidative status need to be studied in order to understand this disorder. We also accentuate the need for ophthalmic genetic facilities in all ophthalmology setups. How to cite this article: Faiq M, Sharma R, Dada R, Mohanty K, Saluja D, Dada T. Genetic, Biochemical and Clinical Insights into Primary Congenital Glaucoma. J Current Glau Prac 2013;7(2):66-84.

Selective Laser Trabeculoplasty: An Overview.

Given the obvious quality of life concerns with medical and surgical lowering of intraocular pressure (IOP), lasers have received considerable attention as a therapeutic modality for glaucoma. Selective laser trabeculoplasty (SLT) is increasingly being used in clinical practice as both the primary procedure and as an adjunct to medical and surgical therapy. Preliminary published evidence suggests that SLT is an effective, compliance-free, repeatable and safe therapeutic modality having only minor, transient, self-limiting or easily controlled side effects with no sequelae. This review attempts a broad overview of the current knowledge of its mechanism, efficacy, indications and limitations, point out the knowledge lacunae that still exist with respect to this highly promising technology which has captured the attention of glaucoma surgeons all over the world. How to cite this article Jha B, Bhartiya S, Sharma R, Arora T, Dada T. Selective Laser Trabeculoplasty: An Overview. J Current Glau Prac 2012;6(2):79-90.

Comparison of Eye Drop Instillation Before and After Use of Drop Application Strips in Glaucoma Patients on Chronic Topical Therapy.

Purpose:To evaluate the impact of using drop application strips on eye drop instillation in glaucoma patients on chronic topical ocular hypotensive therapy. Methods:A total of 72 patients with primary open-angle glaucoma with an uncorrected visual acuity of 3/60 or more, self-administering topical antiglaucoma medication for >1 year were evaluated. One eye of each patient was included in the study. Patients were instructed to instill 0.5% carboxymethyl cellulose drop in 1 eye. They were then instructed to instill the same drop using the drop application strips. Results:Mean age of the patients included in the study was 50.39±12.04 years. Before assistance of drop application strips, 35 (48.61%) patients placed the drop into the eye without any contact of the dropper nozzle, and, after application of the drop application strips, 66 (91.67%) patients placed the drop in the eye without any contact (P=0.025). The number of patients putting the first drop of drug into the eye without spilling over the adenexae increased from 30 (41.67%) to 45 (62.5%) after application of the strip (P<0.001). The mean number of drops instilled to get 1 drop into the eye decreased from 2±0.95 to 1.56±0.78 when the drop application strip was used (P<0.001). Conclusions:Use of a drop application strip causes a significant decrease in contact of the eye drop bottle nozzle with the eyeball and eyelid, decreases the number of drops instilled to get 1 drop into the eye, and is associated with an overall improvement in eye drop instillation.