Publications by authors named "S Nithya"

19 Publications

A review of novel coronavirus disease (COVID-19): based on genomic structure, phylogeny, current shreds of evidence, candidate vaccines, and drug repurposing.

3 Biotech 2021 Apr 27;11(4):198. Epub 2021 Mar 27.

Department of Integrative Biology, School of BioSciences and Technology, Vellore Institute of Technology, Tamil Nadu, Vellore, 632 014 India.

Coronavirus disease (COVID-19) pandemic is instigated by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As of March 13, 2021, more than 118.9 million cases were infected with COVID-19 worldwide. SARS-CoV-2 is a positive-sense single-stranded RNA beta-CoV. Most COVID-19 infected individuals recover within 1-3 weeks. Nevertheless, approximately 5% of patients develop acute respiratory distress syndrome and other systemic complications, leading to death. Structural genetic analyses of SARS-CoV-2 have shown genomic resemblances but a low evolutionary correlation to SARS-CoV-1 responsible for the 2002-2004 outbreak. The S glycoprotein is critical for cell adhesion and the entrance of the virus into the host. The process of cell entry uses the cellular receptor named angiotensin-converting enzyme 2. Recent evidence proposed that the CD147 as a SARS-CoV-2's potential receptor. The viral genome is mainly held by two non-structural proteins (NSPs), ORF1a and ORF1ab, along with structural proteins. Although NSPs are conserved among the βCoVs, mutations in NSP2 and NSP3 may play critical roles in transmitting the virus and cell tropism. To date, no specific/targeted anti-viral treatments exist. Notably, more than 50 COVID-19 candidate vaccines in clinical trials, and a few being administered. Preventive precautions are the primary strategy to limit the viral load transmission and spread, emphasizing the urgent need for developing significant drug targets and vaccines against COVID-19. This review provides a cumulative overview of the genomic structure, transmission, phylogeny of SARS-CoV-2 from Indian clusters, treatment options, updated discoveries, and future standpoints for COVID-19.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-021-02749-0.
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http://dx.doi.org/10.1007/s13205-021-02749-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003899PMC
April 2021

Ex vivo model for studying endothelial tip cells: Revisiting the classical aortic-ring assay.

Microvasc Res 2020 03 30;128:103939. Epub 2019 Oct 30.

Department of Biotechnology, Anna University, Chennai 600 025, India; Vascular Biology Laboratory, AU-KBC Research Centre, MIT Campus, Chennai 600 044, India. Electronic address:

A drug undergoes several in silico, in vitro, ex vivo and in vivo assays before entering into the clinical trials. In 2014, it was reported that only 32% of drugs are likely to make it to Phase-3 trials, and overall, only one in 10 drugs makes it to the market. Therefore, enhancing the precision of pre-clinical trial models could reduce the number of failed clinical trials and eventually time and financial burden in health sciences. In order to attempt the above, in the present study, we have shown that aortic ex-plants isolated from different stages of chick embryo and different regions of the aorta (pulmonary and systemic) have differential sprouting potential and response to angiogenesis modulatory drugs. Aorta isolated from HH37 staged chick embryo showed 16% (p < 0.001) and 11% (p < 0.001) increase in the number of tip cells at 72 h of culture compared to that of HH35 and HH29 respectively. The ascending order of the number of tip cells was found as central (Gen II), proximal (Gen I) and distal (Gen III) in a virtual zonal segmentation of endothelial sprouting. The HH37 staged aortas displayed differential responses to pro- and anti-angiogenic drugs like Vascular endothelial growth factor (VEGF), nitric oxide donor (spNO), and bevacizumab (avastin), thalidomide respectively. The human placenta tissue-culture however evinced endothelial sprouting only on day 12, with a gradual decrease in the number of tip cells until 21 days. In summary, this study provides an avant-garde angiogenic model emphasized on tip cells that would enhance the precision to test next-generation angiogenic drugs.
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http://dx.doi.org/10.1016/j.mvr.2019.103939DOI Listing
March 2020

Loricrin expression and its implication in oral submucous fibrosis, hyperkeratosis and normal mucosa with association to habits - An immunohistochemical study.

J Oral Biol Craniofac Res 2019 Jul-Sep;9(3):226-231. Epub 2019 May 20.

Department of Oral Pathology and Microbiology, Ragas Dental College and Hospital, Chennai, Tamil Nadu, India.

Objective: The coarse fibres of areca nut and the continuous friction from occluding teeth are major causes of mechanical stress to the oral mucosa in conditions like oral submucous fibrosis and frictional keratosis. The continuous micro trauma provided in areca nut chewers, creates an environment where the keratinocytes exhibit alteration. Loricrin, is expressed abundantly in keratinizing epithelium in response to mechanical stress. Their expression or absence could play a role in malignant transformation. This study attempts to assess the potential of Loricrin as an early diagnostic marker in patients with chewing habit.

Methods: 73 archival samples of formalin fixed, paraffin embedded tissue specimens histopathologically confirmed, were segregated as normal mucosa 11, hyperkeratotic 32 and oral submucous fibrosis 30 and stained with antibodies to Loricrin and graded as negative, mild, moderate and intense based on the staining intensity. Pearson's chi square test was done for statistical analysis.

Results: Loricrin expression was observed in all groups with staining in the stratum granulosum showing a significant association to habits (P = 0.000).

Conclusion: This prominent staining indicates a compensatory cytoskeletal rearrangement of surface epithelium during cell division in early oral submucous fibrosis showing potential as an early marker of the condition.
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http://dx.doi.org/10.1016/j.jobcr.2019.05.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6536888PMC
May 2019

Green synthesis of silver nanoparticles using Nardostachys jatamansi and evaluation of its anti-biofilm effect against classical colonizers.

Microb Pathog 2019 Jan 22;126:1-5. Epub 2018 Oct 22.

Department of Chemistry, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur, 613401, India. Electronic address:

In this communication, we present the green synthesis of silver nanoparticles (AgNPs) using medicinally important Nardostachys jatamansi rhizome extract in the presence of sunlight. UV-vis spectroscopy, Fourier Transform Infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and Energy dispersive X-ray analysis (EDX) were employed to characterize the synthesized AgNPs. UV-visible spectroscopic studies confirmed the presence of biosynthesized AgNPs. Transmission Electron Microscopic studies revealed the structure of spherical AgNPs in the diameter range of 10-15 nm. Energy dispersive X-ray analysis and elemental mapping clearly confirmed the presence of silver in AgNPs samples. Interestingly, biomolecules functionalised AgNPs exhibited a remarkable antioxidant, anti-inflammatory, and anti-biofilm activities and hence biosynthesized AgNPs from N. jatamansi can be used as a promising biomaterial for biomedical applications.
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http://dx.doi.org/10.1016/j.micpath.2018.10.024DOI Listing
January 2019

Optimization of Human Semen Extender Components for Cryopreservation Using Statistical Tools.

Cryo Letters 2017 Nov/Dec;38(6):434-444

School of Biosciences and Technology, VIT University, Near Katpadi Road, Vellore, Tamil Nadu, India.

  BACKGROUND: Human sperm cell preservation is an important part of assisted reproductive technology (ART).

Objective: This study aimed to find the essential and significant components in semen preservation extender required to prolong the shelf life of human spermatozoa.

Materials And Methods: By using the statistical tool 'Plackett-Burman design' the significant components present in E4 extender (formulated in our previous study) was determined by reducing the unacceptable large number of trial experiments from the full factorial method.

Results: It was found that vitamin E, taurine and vitamin C were highly significant in maintaining the stability of sperm cells; and egg yolk, vitamin C and glucose were highly significant in sustaining the motility of the sperm cells. R values for the models were 0.9950 and 0.9960 respectively. In the optimized E4 extender 75 % and 81 % of the total motility was retained by the sperm cells from infertile and fertile samples respectively after cryopreservation. Also an increase in zeta potential was observed indicating a reduction in stability in both fertile and infertile sample (4 % and 18 % respectively) after cryopreservation in E4 medium, which was much less when compared with the sample preserved only with glycerol as cryoprotectant (11 % and 69 % for infertile and fertile samples respectively).

Conclusion: The major components present in E4 semen extender was successfully optimized for further use.
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June 2018