Pre-Operative SARS CoV-2 Rapid Antigen Test and Reverse Transcription Polymerase Chain Reaction: A conundrum in surgical decision making.

PURPOSE: Since the eye is in close proximity to the oro-nasal cavity, transmission of SARS CoV-2 is higher during ophthalmic surgical procedures, it is vital to ensure the safety of the healthcare team by pre-operative Rapid Antigen Test (RAT) and real-time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) for SARS CoV-2 viral RNA of all patients planned for elective or emergency surgery. Hence, understanding the profile of pre-operative RAT and real-time RT-PCR among patients planned for various ophthalmic procedures, will help us make better decisions for future guidelines, for optimal planning of ophthalmic elective or emergency surgeries, keeping in mind the current scenario. METHODS: This is a prospective descriptive study conducted on patients planned for elective or emergency ophthalmic surgeries, who had no COVID-19-related symptoms pre-operatively and were subjected to preoperative RAT and real-time RT-PCR of nasopharyngeal and throat swabs for SARS CoV-2 viral RNA. Data was compiled and statistically analysed. RESULTS: 204 patients underwent pre-operative RAT and RT-PCR testing; of which, 85 were females and 119 were males. Mean age of the study population was 51.44 ± 16.501 years. Among the 204, 2 tested positive for SARS CoV-2 with Rapid Antigen testing as well as RT-PCR and 10 patients tested positive via RT-PCR after a negative RAT result of the same sample. CONCLUSION: Pre-operative testing for COVID-19 disease is indispensable as there is a high chance of transmission from patient to healthcare workers. RAT has the advantage of quick results and may play a role in case of emergency procedures. However, it is prudent to perform the more sensitive real-time RT-PCR before any elective, non-emergency procedures or surgeries to avoid any undue risk to the healthcare team.

Ophthalmic manifestations in the COVID-19 clinical spectrum.

PURPOSE: The aim of this study was to determine the frequency and various types of ophthalmic manifestation of patients with COVID-19. METHODS: This is a prospective observational study conducted on patients with SARS-Co-V-2 infection, at a dedicated tertiary COVID-19 hospital in South India from April 1 to July 31, 2020. At the time of their admission to the COVID hospital, demographic data such as name, age, sex was recorded. A thorough history regarding the onset, duration, progression, nature of symptoms and its associated factors, medication history, treatment history were elicited and documented. Ocular examination was performed under torchlight by an ophthalmologist posted for COVID duty. Further investigations including imaging were sought for, depending on clinical indications. Serial follow-up examinations of all patients were carried out every 72 hours or when patients complained of any ocular symptoms whichever earlier, until discharge. All relevant data were compiled and statistically analyzed. RESULTS: A total of 2742 patients were examined. Of them, 1461 (53.28%) were males and 1281 (46.72%) were females. The mean age (±SD) was 39.46 ± 17.63 years. None of the patients in our study had any ocular symptoms or signs as the presenting complaint at the time of their admission. On subsequent follow-up, only 20 (0.72%) developed ocular manifestations, of which 19 (95%) had features suggestive of Bilateral viral conjunctivitis. However, 1 (5%) patient had orbital cellulitis secondary to pansinusitis. CONCLUSION: Ophthalmic manifestations in the clinical spectrum of COVID-19 infection are uncommon and unlikely to be the presenting clinical impression. However, it has broadened our view to a wider spectrum of COVID-19 presentations enhancing our clinical acumen for staunch detection of COVID-19 suspects in our daily practice, augmenting early diagnosis and management and also break the chain of transmission for the greater good of humanity.

Recombinant 20.8-kDa protein of Mycobacterium avium subsp. paratuberculosis-based sero-diagnosis of paratuberculosis.

Johne's disease or paratuberculosis is a chronic infectious enteric disease of ruminants caused by the intracellular pathogen. The control of the Johne's disease is hampered by lack of specific diagnostic tests. In this study, we have cloned and expressed the N-terminal region of the locus tag Map 1637c encoding 20.8-kDa (r20.8) protein of Mycobacterium avium subsp. paratuberculosis. The recombinant protein r20.8 was expressed in high levels in Escherichia coli. The protein r20.8 was purified by single-step chromatography using Ni-NTA agarose. The protein r20.8 was reacted with anti-r20.8 antibodies as well as cattle sera infected with Map on Western blot. ELISA using well-characterized sera (both positive and negative; n = 60 each) Map-infected and non-infected cattle, respectively, yielded a sensitivity of 73.3% and a specificity of 98.3%. The 20.8 kDa protein expressed in the present study will prove useful as reagent in diagnostic test.

Phase evolution, characterization, and impedance spectroscopic analysis of nanocrystalline SrBi2Nb2O9 in glassy Li2B4O7 matrix.

Transparent glass composites in the system (100 - x) Li2B4O7 - x SrBi2Nb2O9 (where x = 5, 10, 15, 20, 25, and 30, in molar ratio) were fabricated by conventional melt-quenching technique. The amorphous nature of the as-quenched glass composites was confirmed via X-ray powder diffraction (XRD) studies. Differential thermal analyses (DTA) established the glassy nature of the as-quenched samples. Glass nanocomposites (GNC's) with high-optical transparency were obtained by controlled heat-treatment of the glass composites at 750 K/6 h. Perovskite SrBi2Nb2O9 (SBN) phase formation through an intermediate fluorite phase was confirmed by XRD and transmission electron microscopy (TEM). The dielectric constant (epsilon r) in the frequency range from 100 Hz to 40 MHz at room temperature increases whereas dielectric loss (D) decreases with increase in SBN content in Li2B4O7 glass matrix. Impedance spectroscopy employed to rationalize the electrical behavior of the as-quenched glasses and glass nanocomposites suggests the coexistence of electronic and ionic conduction in these materials. The optical transmission and band-gap energy of these composites were found to be crystallite size dependent.

Monoclonal antibody: high density culture of hybridoma cells and downstream processing for IgG recovery.

Getting higher yields of monoclonal antibody (MAb) is a problem in Hybridoma Technology which has two major bottlenecks--(a) poor yield of hybridized cells; and (b) low cellular productivity of MAb in culture. There are three ways of obtaining high MAb yield in vitro--(a) large scale culture of hybrid cells; (b) high density culture; and (c) enhancing individual cellular productivity in culture. Currently, focus is on correct synergistic combination of fortified nutrient media, bioreactor design and mode of operation. Maximisation of cell culture longevity, maintenance of high specific antibody secretion rates, nutrient supplementation, waste product minimization and control of environmental conditions are important parameters for improvement of large scale production of MAb. Though, MAb yield has enhanced rapidly over the decade, there is a growing concern for decrease in quality of MAb secreted. Further research is therefore necessary to take full advantage of MAb as a potential diagnostic agent for in vivo therapy.

Getting higher yields of monoclonal antibody in culture.

Getting higher yields of monoclonal antibody (MAb) is a problem in Hybridoma Technology which has two major bottlenecks: a) poor yield of hybridized cells, b) low cellular productivity of MAb in culture. There are three ways of obtaining high MAb yield in vitro a) Large scale culture, b) high density culture and c) enhancing individual cellular productivity in culture. Currently, the focus is on the correct synergistic combination of fortified nutrient media, bioreactor design and mode of operation. Maximization of cell culture longevity, maintenance of high specific antibody secretion rates, nutrient supplementation, waste product minimization and control of environmental conditions are important parameters for improvement of large scale production of MAb. Though, MAb yields have improved rapidly over the decade, there is a growing concern for the decrease in quality of MAb secreted. Further research is therefore necessary to take full advantage of MAb as a potential diagnostic agent for in vivo therapy.

Action of the herbicide butachlor on cholinesterases in the freshwater snail Pila globosa (Swainson).

Butachlor action on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activates in central nervous tissue of the snail Pila globosa was assayed following the method of ELLMAN et al1, in vitro by adding butachlor directly (10-100 mu moles), to tissue homogenates and in in vivo by exposing the snails to sub-lethal concentration (26.6 ppm) and taking out the tissue for experimentation at different intervals (3, 6, 12, 24 and 48 h) of exposure. The enzyme activities decreased in a dose-dependent manner in vitro, and up to 12-24 h in vivo after which they showed recovery towards the control. The inhibition of cholinesterases by butachlor in vitro indicates a direct action of the herbicide on these enzymes. Presumably butachlor exercises its neurotoxic effects through cholinergic impairment in a way similar to that of organophosphates and carbamates.

Diode-pumped optical parametric oscillator.

Diode-pumped optical parametric oscillation has been demonstrated for the first time to our knowledge in a single Nd:MgO:LiNbO(3) nonlinear crystal. The crystal is pumped by a semiconductor diode laser array at 812 nm. The Nd(3+) ions absorb the 812-nm radiation to generate 1084-nm laser oscillation. On internal Q switching the 1084-nm radiation pumps the LiNbO(3) host crystal that is angle cut at 46.5 degrees and generates optical parametric oscillation. The oscillation threshold that is due to the 1084-nm laser pump with a pulse length of 80 ns in a 1-mm-diameter beam was measured to be approximately 1 mJ and produced 0.5-mJ output at 3400-nm signal wavelength.

Community awareness about leprosy and participation in National Leprosy Control Programme.

To evaluate the health education component of our National Leprosy Control Programme (NLCP), 955 adult community members and 225 adult leprosy patients were interviewed with a view to assess their awareness about leprosy and participation in NLCP. The early signs/symptoms of leprosy were poorly perceived by the community. Majority of the community (81%) and patients (75%) were unaware or held superstitious ideas about causation of leprosy. The spread of disease through close contact with patient(s) was better known to the community (65%) than the patients (45%); but the role of open cases in spread was stressed by more patients (17%) than community (5.5%). About 31% community and 23% patients had no idea about the ways to prevent leprosy spread. As against 89% patients, only 62% community believed in curability of leprosy with early and regular treatment; but 20% of the community members did not know where to refer patients for treatment. The causation and prevention of deformities were poorly perceived by 71% patients, and likewise 62% of the patients did not take precaution(s) to prevent the deformities. About 32% respondents were unaware of the efforts being made to control leprosy; and their (79-84% respondents) participation in NLCP was very vague. About 44% community members showed prejudice towards leprosy. The NLCP infra-structure and mass media could not educate community effectively. The implications of the findings are discussed in this paper.