Management of double optic disc pit complicated by maculopathy

Optic disc pit (ODP) is a rare, congenital, cavitary anomaly of the optic disc. Usually, single ODP occurs in an eye and only eleven cases of double ODP have been reported so far in the literature. In the present study, we report a case of unilateral double ODP, with both the pits present in opposite disc segments. They were associated with serous retinal detachment at the macula and retinal pigment epithelium degeneration nasal to disc. The case was managed successfully with vitrectomy, internal limiting membrane peeling, plugging the pits with homologous partial-thickness scleral flaps, and gas tamponade.

Reversible blindness in a patient with closantel toxicity

To describe the optical coherence tomography (OCT) and electrophysiological changes in a case of closantel toxicity. A 25-year-old patient presented with sudden painless defective vision following intake of closantel. Visual acuity (VA) was counting fingers at 5 m in both eyes (BE). OCT revealed disruption of outer retinal layers and electroretinogram (ERG) and visual evoked potential (VEP) were subnormal in BE. The patient was treated with systemic corticosteroids, after which his VA improved to 6/9, OCT revealed preservation of central outer retinal layers, and ERG and VEP responses improved in BE. This is the first case report of successful treatment with systemic steroids for closantel-related reversible blindness.

Perfluoro-n-octane-assisted mega Weiss-ring technique for posterior vitreous detachment induction in retinal detachment

Induction of posterior vitreous detachment (PVD) is one of the most critical steps for the success of retinal detachment (RD) surgery. Failure to completely remove the vitreous can result in re-detachments. We describe a novel technique to induce PVD. After core vitrectomy, perfluorocarbon liquid (PFCL) is injected. The vitreous on the posterior pole is gently stroked, with a diamond-dusted membrane scraper, to create a defect in it. This defect is gradually enlarged to create a ring of rolled out vitreous. The entire vitreous is removed in form of a sheet by lifting the edges of the ring using an internal limiting membrane peeling forceps. PFCL naturally slides into the potential space, gradually extending the vitreous detachment peripherally. With this technique, the vitreous sheet in case of RD can easily, effectively and safely be removed with this technique.

Bilateral optic nerve aplasia with corpus callosum hypogenesis in an otherwise healthy child: Report of a rare case

Optic nerve (ON) aplasia is a rare congenital anomaly. It is characterised by the absence of optic nerve, nerve fibre layer, ganglion cells, and retinal blood vessels. ON aplasia is usually unilateral. Bilateral cases are very rare. We report such a rare case with bilateral ON aplasia and corpus callosum hypogenesis. An 11-month-old male child presented with a history of not seeing or following objects since birth. On examination, the child had microcornea and the absence of an optic disc in both the eyes. In addition, the right eye showed partial aniridia and few rudimentary retinal vessels in the posterior pole, while the left eye showed a chorioretinal coloboma but no evidence of any retinal blood vessels. Flash visual evoked potential was nonrecordable in both the eyes. MRI brain and orbit showed congenital aplasia of the ON on both sides with poorly developed optic chiasm, optic tract, and lateral geniculate body along with the features of corpus callosum hypogenesis. Child had no other systemic or endocrinological abnormalities.

Wyburn–Mason syndrome presenting with bilateral retinal racemose hemangioma with unilateral serous retinal detachment

Wyburn–Mason syndrome is associated with unilateral retinal racemose hemangioma. Rarely, it presents with bilateral and symmetrical grade of malformation. We describe a 37-year old male, who presented with Wyburn–Mason syndrome presenting with bilateral but asymmetrical retinal hemangioma. The eye with advanced grade of hemangioma was complicated with exudation, intraretinal fluid, neurosensory detachment, and reduced vision. He was treated with one intravitreal injection of bevacizumab, after which both the intraretinal fluid and neurosensory detachment resolved. His vision improved and was maintained till 1 year of follow-up.

Retrospective study of changes in ocular coherence tomography characteristics after failed macular hole surgery and outcomes of fluid-gas exchange for persistent macular hole

Purpose: The aim is to study the changes in ocular coherence tomography (OCT) parameters of large (?400 ?) full-thickness macular holes (FTMHs) after a failed surgery and evaluate the outcome of fluid-gas exchange (FGE) in the treatment of persistent macular hole and role of OCT in predicting outcome after the secondary intervention. Methods: Changes occurring in the OCT parameters of FTMH after a failed vitrectomy were evaluated. FGE was done in an operating room with three pars plana sclerostomy ports. The anatomical and functional outcomes of FGE for these persistent macular holes were also assessed. Anatomical closure was defined as the flattening of the hole with resolution of subretinal cuff of fluid. Anatomical success after FGE was defined as flattening of macular hole with the resolution of subretinal cuff of fluid and neurosensory retina completely covering the fovea. Functional success was defined as an improvement of at least one line of best-corrected visual acuity (BCVA). Results: Twenty-eight eyes (28 patients) were included in the study. After the failed vitrectomy, OCT showed an increase in the base diameter, opening diameter, and height of the hole. After the secondary procedure, anatomical closure was achieved in 89.3% eyes. Mean BCVA improved from logMAR 0.88 � 0.24 (20/152) to logMAR 0.66 � 0.24 (20/91) (P < 0.001). Eight (28.6%) patients achieved final BCVA ?20/60. Functional success was obtained in 19 patients (67.9%). There was no association between anatomical success after FGE and any of the pre-FGE OCT parameters or indices. Conclusion: Unsuccessful surgery causes swelling of the outer and middle retinal layers with retraction of inner layers of the retina. Performing FGE while visualizing the retina is a good option for the treatment of large persistent macular holes as it causes complete drying of the macula, better success rates, and a reduced complication rate. Pre-FGE OCT does not help in predicting the outcome of FGE for persistent macular hole.

Kinetic behaviour of calf intestinal alkaline phosphatase with pNPP.

The hydrolysis of p-nitrophenyl phosphate (pNPP) by calf intestinal alkaline phosphatase (CIAP) was investigated with respect to kinetic parameters such as Vmax, Km and Kcat under varying pH, buffers, substrate concentration, temperature and period of incubation. Highest activity was obtained with Tris-HCl at pH 11, while in the case of glycine-NaOH buffer the peak activity was recorded at pH 9.5. The enzyme showed the following kinetic characteristics with pNPP in 50 mM Tris-HCl at pH 11 and 100 mM glycine-NaOH at pH 9.5 at an incubation temperature of 37°C: Vmax, 3.12 and 1.6 µmoles min-1 unit-1; Km, 7.6 × 10-4 M and 4 × 10-4 M; and Kcat, 82.98 s-1 and 42.55 s-1, respectively. CIAP displayed a high temperature optimum of 45°C at pH 11. The kinetic behaviour of the enzyme under different parameters suggested that the enzyme might undergo subtle conformational changes in response to the buffers displaying unique characteristics. Bioprecipitation of Cu2+ from 50 ppm of CuCl2 solution was studied where 64.3% of precipitation was obtained. Pi generated from CIAP-mediated hydrolysis of pNPP was found to bind with copper and precipitated as copper-phosphate. Thus, CIAP could be used as a test candidate in bioremediation of heavy metals from industrial wastes through generation of metal-phosphate complexes.

Observations on life cycle of certain spiders from Western Ghats of Tamil Nadu.

Survey was conducted, in the different forests ecosystems of Western Ghats of Tamil Nadu in Nilgris, Coimbatore, Erode, Virudhunagar and Tirunelveli districts to collect the adult spiders and study them taxonomically. Fifty-six species of spider collections were made. From the fifty six, biology was studied for six spider species, such as Micrommata virescens n.sp., Oxyopes javanus, Peucetia virridana, Agelena kariansholensis n.sp., Heteropoda venatoria and Olios hampsoni. Biology studies with Peucetia virridana and Micrommata virescens showed that both species took more than 350 days to complete their life cycles. Heteropoda venetoria and Oxyopes javanus took more than 250 days to complete their life cycle. Agelena kariansholensis took 381 days and Olios hampsoni took 345 days to complete their life cycles. 30% of Peucetia virridana and more than 20% of Heteropoda venatoria and Micrommata virescens and 7% of Oxyopes javanus developed into adults in captivity.

Bioremediation of chromium contaminated environments.

Bioremediation is the most promising and cost effective technology widely used nowadays to clean up both soils and wastewaters containing organic or inorganic contaminants. Discharge of chromium containing wastes has led to destruction of many agricultural lands and water bodies. Utilisation of chromium(Cr) reducing microbes and their products has enhanced the efficiency of the process of detoxification of Cr(VI) to Cr(III). This review focuses mainly on the current technologies prevalent for remediation like natural attenuation, anaerobic packed bed bioreactors (using live cells, Cr(VI) reductases or their byproducts) and use of engineered microorganisms. Treatment of wastewaters by biosorption or using biofilms and immobilized microbial cells are also discussed.

Anaerobic biodegradation of aromatic compounds.

Many aromatic compounds and their monomers are existing in nature. Besides they are introduced into the environment by human activity. The conversion of these aromatic compounds is mainly an aerobic process because of the involvement of molecular oxygen in ring fission and as an electron acceptor. Recent literatures indicated that ring fission of monomers and obligomers mainly occurs in anaerobic environments through anaerobic respiration with nitrate, sulphate, carbon dioxide or carbonate as electron acceptors. These anaerobic processes will help to work out the better situation for bioremediation of contaminated environments. While there are plenty of efforts to reduce the release of these chemicals to the environment, already contaminated sites need to be remediated not only to restore the sites but to prevent the leachates spreading to nearby environment. Basically microorganisms are better candidates for breakdown of these compounds because of their wider catalytic mechanisms and the ability to act even in the absence of oxygen. These microbes can be grouped based on their energy mechanisms. Normally, the aerobic counterparts employ the enzymes like mono-and-dioxygenases. The end product is basically catechol, which further may be metabolised to CO2 by means of quinones reductases cycles. In the absense of reductases compounds, the reduced catechols tend to become oxidised to form many quinone compounds. The quinone products are more recalcitrant and lead to other aesthetic problems like colour in water, unpleasant odour, etc. On the contrary, in the reducing environment this process is prevented and in a cascade of pathways, the cleaved products are converted to acetyl co-A to be integrated into other central metabolite paths. The central metabolite of anaerobic degradation is invariably co-A thio-esters of benzoic acid or hydroxy benzoic acid. The benzene ring undergoes various substitution and addition reactions to form chloro-, nitro-, methyl- compounds. For complete degradation the side chains must be removed first and then the benzene ring is activated by carboxylation or hydroxylation or co-A thioester formation. In the next step the activated ring is converted to a form that can be collected in the central pool of metabolism. The third step is the channeling reaction in which the products of the catalysis are directed into central metabolite pool. The enzymes involved in these mechanisms are mostly benzyl co-A ligase, benzyl alcohol dehydrogenase. Other enzymes involved in this path are yet to be purified though many of the reactions products that have been theoretically postulated have been identified. This is mainly due to the instability of intermediate compounds as well as the association of the enzyme substrate is femoral and experimental conditions need to be sophisticated further for isolation of these enzymes. The first structural genes of benzoate and hydroxy benzoate ligases were isolated from Rhodopseudomonas palustris. This gene cluster of 30 kb size found in Rhodopseudomonas palustris coded for the Bad A protein. Similarly, some of the bph A,B,C and D cluster of genes coding for the degradation of pentachlorobenzenes were located in Pseudomonas pseudoalgaligenesKF 707.