INFECTION OF GASTRO-INTESTINAL TRACT BY SARS-CoV-2 AND ITS POTENTIAL FOR FAECAL-ORAL TRANSMISSION: A LITERATURE REVIEW

Context: SARS-CoV-2, has already affected more than 180 countries. 3,175,207 confirmed cases and 224,173 deaths due to the disease were reported worldwide till 1st May 2020. WHO has declared it a Public Health Emergency of International Concern. Aims: To present information from worldwide literature on infection of gastro-intestinal tract by SARS-CoV-2 and its potential for faecal-oral transmission. Material and Methods: Literature search was carried out using Google Scholar and PubMed in 3rd week of April, 2020. Search terms used were “SARS-CoV-2” or “COVID-19” or “New Coronavirus” or “Coronavirus” in title and “Transmission” or “Faecal” or “Oral” anywhere in the article. Studies from the year 2019 to 2020 published in “English” language were included in the search. Results: 15 studies were found relevant and were included in the review. Studies reported that SARS-CoV-2 infects and replicates in gastro-intestinal tract and manifests enteric symptoms. Viral RNA is excreted in stool. Fecal samples were found to be positive for the viral RNA for many days even after respiratory samples become negative. Virus has been detected in anal swabs and live virus could be successfully isolated from stool specimen. The virus was also reported to be viable in the environment for many days. Conclusions: SARS-CoV-2 can potentially be transmitted by faecal-oral route. The transmission can occur even after respiratory symptoms subside and respiratory tract samples test negative for the virus. Appropriate policy response is needed for awareness, testing, discharge and quarantine of patients to prevent spread of the disease. Keywords--SARS-CoV-2, Coronavirus Outbreak, COVID-19, New Coronaviru

Postage stamp multiple anterior capsulorhexisotomies in pediatric cataract surgery

BACKGROUND: Capsule related complications are common following pediatric cataract surgery. We report a new technique of multiple anterior capsulorhexisotomies after lens aspiration and intraocular lens (IOL) implantation. METHODS: After performing automated lens aspiration, an IOL was implanted into the capsular bag. A bent 26 gauge needle was introduced through one side port and multiple small cuts were made in one half of the circumference of the anterior capsular rim by making a radial movement of the needle tip centripetally over the margin of the anterior capsular rim. The needle was again introduced through the other side port and multiple similar cuts were made in the other half thereby creating nearly 20 – 30 cuts at the margin of the anterior capsular rim. RESULTS: The mean size of the primary capsulorhexis was 4.33 ± 0.20 mm. A uniform enlargement of the capsulorhexis could be performed in all the eyes without peripheral extension in any of the eyes. There was no damage to the posterior capsule and no scratch mark on the IOL. In one eye, the primary capsulorhexis was slightly eccentric, though it was covering the IOL optic all around. The rhexisotomies in this eye were limited to the capsular rim that was overlapping more on the IOL optic (sectoral anterior capsulorhexisotomies). CONCLUSION: The technique of postage stamp anterior capsulorhexisotomies is a feasible technique in pediatric cataracts

Holographic studies of quasi-topological gravity

Quasi-topological gravity is a new gravitational theory including curvature-cubed interactions and for which exact black hole solutions were constructed. In a holographic framework, classical quasi-topological gravity can be thought to be dual to the large $N_c$ limit of some non-supersymmetric but conformal gauge theory. We establish various elements of the AdS/CFT dictionary for this duality. This allows us to infer physical constraints on the couplings in the gravitational theory. Further we use holography to investigate hydrodynamic aspects of the dual gauge theory. In particular, we find that the minimum value of the shear-viscosity-to-entropy-density ratio for this model is $\eta/s \simeq 0.4140/(4\pi)$.Comment: 45 pages, 6 figures. v2: References adde

Holographic c-theorems in arbitrary dimensions

We re-examine holographic versions of the c-theorem and entanglement entropy in the context of higher curvature gravity and the AdS/CFT correspondence. We select the gravity theories by tuning the gravitational couplings to eliminate non-unitary operators in the boundary theory and demonstrate that all of these theories obey a holographic c-theorem. In cases where the dual CFT is even-dimensional, we show that the quantity that flows is the central charge associated with the A-type trace anomaly. Here, unlike in conventional holographic constructions with Einstein gravity, we are able to distinguish this quantity from other central charges or the leading coefficient in the entropy density of a thermal bath. In general, we are also able to identify this quantity with the coefficient of a universal contribution to the entanglement entropy in a particular construction. Our results suggest that these coefficients appearing in entanglement entropy play the role of central charges in odd-dimensional CFT's. We conjecture a new c-theorem on the space of odd-dimensional field theories, which extends Cardy's proposal for even dimensions. Beyond holography, we were able to show that for any even-dimensional CFT, the universal coefficient appearing the entanglement entropy which we calculate is precisely the A-type central charge.Comment: 62 pages, 4 figures, few typo's correcte

Contact lens rehabilitation following repaired corneal perforations

BACKGROUND: Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. METHOD: Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. RESULTS: Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60%) required aphakic contact lenses. The best corrected visual acuity (BCVA) of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25%) eyes with spectacle correction and 37 (92.5%) eyes with the use of contact lens (p < 0.001). The best-corrected visual acuity with spectacles was 0.20 ± 0.13 while the same with contact lens was 0.58 ± 0.26. All the patients showed an improvement of ≥ 2 lines over spectacles in the snellen's acuity chart with contact lens. CONCLUSION: Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries

Protective Immunity to Mycobacterium tuberculosis Infection by Chemokine and Cytokine Conditioned CFP-10 Differentiated Dendritic Cells

BACKGROUND: Dendritic cells (DCs) play major roles in mediating immune responses to mycobacteria. A crucial aspect of this is the priming of T cells via chemokines and cytokines. In this study we investigated the roles of chemokines RANTES and IP-10 in regulating protective responses from Mycobacterium tuberculosis (M. tb) 10 kDa Culture Filtrate Protein-10 (CFP-10) differentiated DCs (CFP10-DCs). METHODS AND FINDINGS: Infection of CFP10-DCs with mycobacteria down-modulated RANTES and IP-10 levels. Pathway specific microarray analyses showed that in addition to RANTES and IP-10, mycobacteria infected CFP10-DCs showed reduced expression of many Th1 promoting chemokines and chemokine receptors. Importantly, T cells co-cultured with RANTES and IP-10 conditioned CFP10-DCs mediated killing of mycobacteria from infected macrophages. Similarly, T cells recruited by RANTES and IP-10 conditioned CFP10-DCs mediated significant killing of mycobacteria from infected macrophages. IFN-gamma treatment of CFP10-DCs restored RANTES and IP-10 levels and T cells activated by these DCs mediated significant killing of virulent M. tb inside macrophages. Adoptive transfer of either RANTES and IP-10 or IL-12 and IFN-gamma conditioned CFP10-DCs cleared an established M. tb infection in mice. The extent of clearance was similar to that obtained with drug treatment. CONCLUSIONS: These results indicate that chemokine and cytokine secretion by DCs differentiated by M. tb antigens such as CFP-10 play major roles in regulating protective immune responses at sites of infection

Voltage Gated Calcium Channels Negatively Regulate Protective Immunity to Mycobacterium tuberculosis

Mycobacterium tuberculosis modulates levels and activity of key intracellular second messengers to evade protective immune responses. Calcium release from voltage gated calcium channels (VGCC) regulates immune responses to pathogens. In this study, we investigated the roles of VGCC in regulating protective immunity to mycobacteria in vitro and in vivo. Inhibiting L-type or R-type VGCC in dendritic cells (DCs) either using antibodies or by siRNA increased calcium influx in an inositol 1,4,5-phosphate and calcium release calcium activated channel dependent mechanism that resulted in increased expression of genes favoring pro-inflammatory responses. Further, VGCC-blocked DCs activated T cells that in turn mediated killing of M. tuberculosis inside macrophages. Likewise, inhibiting VGCC in infected macrophages and PBMCs induced calcium influx, upregulated the expression of pro-inflammatory genes and resulted in enhanced killing of intracellular M. tuberculosis. Importantly, compared to healthy controls, PBMCs of tuberculosis patients expressed higher levels of both VGCC, which were significantly reduced following chemotherapy. Finally, blocking VGCC in vivo in M. tuberculosis infected mice using specific antibodies increased intracellular calcium and significantly reduced bacterial loads. These results indicate that L-type and R-type VGCC play a negative role in M. tuberculosis infection by regulating calcium mobilization in cells that determine protective immunity

Crystal Structures Reveal the Multi-Ligand Binding Mechanism of Staphylococcus aureus ClfB

Staphylococcus aureus (S. aureus) pathogenesis is a complex process involving a diverse array of extracellular and cell wall components. ClfB, an MSCRAMM (Microbial Surface Components Recognizing Adhesive Matrix Molecules) family surface protein, described as a fibrinogen-binding clumping factor, is a key determinant of S. aureus nasal colonization, but the molecular basis for ClfB-ligand recognition remains unknown. In this study, we solved the crystal structures of apo-ClfB and its complexes with fibrinogen α (Fg α) and cytokeratin 10 (CK10) peptides. Structural comparison revealed a conserved glycine-serine-rich (GSR) ClfB binding motif (GSSGXGXXG) within the ligands, which was also found in other human proteins such as Engrailed protein, TCF20 and Dermokine proteins. Interaction between Dermokine and ClfB was confirmed by subsequent binding assays. The crystal structure of ClfB complexed with a 15-residue peptide derived from Dermokine revealed the same peptide binding mode of ClfB as identified in the crystal structures of ClfB-Fg α and ClfB-CK10. The results presented here highlight the multi-ligand binding property of ClfB, which is very distinct from other characterized MSCRAMMs to-date. The adherence of multiple peptides carrying the GSR motif into the same pocket in ClfB is reminiscent of MHC molecules. Our results provide a template for the identification of other molecules targeted by S. aureus during its colonization and infection. We propose that other MSCRAMMs like ClfA and SdrG also possess multi-ligand binding properties

Community mobilisation with women's groups facilitated by Accredited Social Health Activists (ASHAs) to improve maternal and newborn health in underserved areas of Jharkhand and Orissa: study protocol for a cluster-randomised controlled trial

Background: Around a quarter of the world's neonatal and maternal deaths occur in India. Morbidity and mortality are highest in rural areas and among the poorest wealth quintiles. Few interventions to improve maternal and newborn health outcomes with government-mandated community health workers have been rigorously evaluated at scale in this setting.The study aims to assess the impact of a community mobilisation intervention with women's groups facilitated by ASHAs to improve maternal and newborn health outcomes among rural tribal communities of Jharkhand and Orissa.Methods/design: The study is a cluster-randomised controlled trial and will be implemented in five districts, three in Jharkhand and two in Orissa. The unit of randomisation is a rural cluster of approximately 5000 population. We identified villages within rural, tribal areas of five districts, approached them for participation in the study and enrolled them into 30 clusters, with approximately 10 ASHAs per cluster. Within each district, 6 clusters were randomly allocated to receive the community intervention or to the control group, resulting in 15 intervention and 15 control clusters. Randomisation was carried out in the presence of local stakeholders who selected the cluster numbers and allocated them to intervention or control using a pre-generated random number sequence. The intervention is a participatory learning and action cycle where ASHAs support community women's groups through a four-phase process in which they identify and prioritise local maternal and newborn health problems, implement strategies to address these and evaluate the result. The cycle is designed to fit with the ASHAs' mandate to mobilise communities for health and to complement their other tasks, including increasing institutional delivery rates and providing home visits to mothers and newborns. The trial's primary endpoint is neonatal mortality during 24 months of intervention. Additional endpoints include home care practices and health care-seeking in the antenatal, delivery and postnatal period. The impact of the intervention will be measured through a prospective surveillance system implemented by the project team, through which mothers will be interviewed around six weeks after delivery. Cost data and qualitative data are collected for cost-effectiveness and process evaluations