Publications by authors named "R Krishnan"

868 Publications

Emerging Super-specialty of Neurology: Intraoperative Neurophysiological Monitoring (IONM) and Experience in Various Neurosurgeries at a Tertiary Care Hospital in Doha, Qatar.

Cureus 2021 Dec 15;13(12):e20432. Epub 2021 Dec 15.

Department of Neurosurgery, Neuroscience Institute, Hamad General Hospital, Doha, QAT.

Introduction Intraoperative neurophysiological monitoring (IONM) helps in better patient outcomes by minimizing risks related to the functional status of the nervous system during surgical procedures. An IONM alert to the surgical team during the surgery can help them identify the cause and take immediate corrective action. IONM confers possible benefits, including improved surgical morbidity and mortality, better patient care, minimal neurological deficits, reduced hospital stay, medical costs, and litigation risk. In addition, a highly skilled IONM team will make a better patient outcome. Methods We retrospectively reviewed 62 consecutive patients who underwent intracranial and spinal neurosurgical procedures. Multimodality IONM was utilized, including somatosensory evoked potentials, transcranial electrical motor evoked potential, spontaneous and triggered electromyography, electroencephalography, electrocorticography, cortical sensory mapping, and direct electrical cortical stimulation. Of a total of 62 patients, two patients revealed neurotonic EMG discharges during IONM, and most patients woke up without any new neurological deficit. Results Sixty-two patients were included, ranging from age 5 to 77 years (mean 43.5 years), with 54.8% men and 45.2% female. Multimodality IONM was used in all patients. Two EMG alerts were recorded during IONM, during a brain tumor resection, and right acetabular hip surgery with postoperative right foot drop. Conclusion Multimodality IONM is the gold standard of care for any surgical services and is used as real-time monitoring of functional integrity of neural structures at risk. If utilized by trained and expert teams, numerous surgeries may benefit from multimodality intraoperative neurophysiologic monitoring.
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http://dx.doi.org/10.7759/cureus.20432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8759984PMC
December 2021

Targeted gene silencing in the nervous system with CRISPR-Cas13.

Sci Adv 2022 Jan 19;8(3):eabk2485. Epub 2022 Jan 19.

Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA.

Cas13 nucleases are a class of programmable RNA-targeting CRISPR effector proteins that are capable of silencing target gene expression in mammalian cells. Here, we demonstrate that RfxCas13d, a Cas13 ortholog with favorable characteristics to other family members, can be delivered to the mouse spinal cord and brain to silence neurodegeneration-associated genes. Intrathecally delivering an adeno-associated virus vector encoding an RfxCas13d variant programmed to target superoxide dismutase 1 (SOD1), a protein whose mutation can cause amyotrophic lateral sclerosis, reduced SOD1 mRNA and protein in the spinal cord by >50% and improved outcomes in a mouse model of the disorder. We further show that intrastriatally delivering an RfxCas13d variant programmed to target huntingtin (HTT), a protein whose mutation is causative for Huntington's disease, led to a ~50% reduction in HTT protein in the mouse brain. Our results establish RfxCas13d as a versatile platform for knocking down gene expression in the nervous system.
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http://dx.doi.org/10.1126/sciadv.abk2485DOI Listing
January 2022

Fungi fabrication, characterization, and anticancer activity of silver nanoparticles using metals resistant Aspergillus niger.

Environ Res 2022 Jan 11:112721. Epub 2022 Jan 11.

School of Renewable Energy, Maejo University, Chiang Mai, 50290, Thailand; College of Medical and Health Science, Asia University, Taichung, Taiwan.

The purpose of this study was to assess the bio-fabrication possibilities of pre-isolated (from bauxite mine tailings) metal-tolerant Aspergillus niger biomass filtrate and the anticancer potential of synthesized silver nanoparticles (AgNPs) tested with a Human Cervical cancer cell line (HeLa cells: Henrietta Lacks cells). The nitrate reduction test demonstrated that A. niger has the ability to reduce nitrate, and filtrate derived from A. niger biomass efficiently fabricated AgNPs from AgNO, as demonstrated by a visible color change from pale greenish to brownish. The UV-visible spectroscopy analysis revealed an absorbance peak at 435 nm, which corresponded to the AgNPs. These AgNPs have been capped and stabilized with several functional groups related to various bioactive molecules such as aldehyde, benzene rings, aldehydic, amines, alcohols, and carbonyl stretch protein molecules. Fourier-Transform Infrared Spectroscopy (FTIR) analysis confirmed the capping and stabilizing chemical bonding pattern. Scanning Electron Microscopy (SEM) revealed that the synthesized AgNPs were spherical, with an average size of 21.38 nm. This bio-fabricated AgNPs has in-vitro anticancer potential when tested against the HeLa cell line due to its potential size and shape. At 100 g mL concentrations of this bio-fabricated AgNPs, the anticancer activity percentage was found to be 70.2%, and the IC value was found to be 66.32 g m. These findings demonstrated that the metal-tolerant A. niger cell filtrate could produce AgNPs with anticancer potential.
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http://dx.doi.org/10.1016/j.envres.2022.112721DOI Listing
January 2022

Phyto-intruders in oral tissues: A polarized light microscopic study.

Int J Health Sci (Qassim) 2022 Jan-Feb;16(1):3-9

Department of Oral and Maxillofacial Surgery, SRM Dental College, Chennai, Tamil Nadu, India.

Objectives: Foreign body reactions are common in the oral cavity due to its proximity to the external environment. Rarely, foreign body of plant origin may be encountered in the histopathological sections making the diagnosis problematic. The aim of the present study was to analyze the histological features of various products of plant origin emphasizing on the pathogenesis of tissue reaction occurring in response to their implantation.

Methods: This observational study included various plant products or phytoproducts commonly consumed in South Indian diet such as rice, curry leaves, coriander leaves, spinach leaves, coconut, green chilli, onion, French beans, urad dal, lentil beans, mustard seed, ginger, and garlic. Formalin-fixed specimens were routinely processed and stained with hematoxylin and eosin. The slides were viewed under light microscope and polarized microscope and evaluated by two oral pathologists.

Results: Each of the phytoproducts had distinctive histological appearance and exhibited positive birefringence. Phytoproducts such as rice, curry leaves, French bean, onion, and green chilli resembled pathological structures such as calcifications, ghost cells, clear cells, atypical adipocytes, and fungal hyphae, respectively.

Conclusions: Plant products appear as puzzling structures in histological section posing difficulties to the pathologist. Recognition of these structures as foreign body based on their histological appearance is inevitable and their identification may avoid unnecessary delay in treatment planning. The current study serves as an atlas for the histology of extraneous material study and also as a reference for the pathologists whenever mystifying structures are encountered.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8721210PMC
January 2022

Beta glucan induced immune priming protects against nervous necrosis virus infection in sevenband grouper.

Fish Shellfish Immunol 2022 Jan 10;121:163-171. Epub 2022 Jan 10.

Department of Aqualife Medicine, Chonnam National University, Yeosu, 59629, Republic of Korea. Electronic address:

In the present study, we studied the effect of β-glucan on the activation of antiviral immune responses against nervous necrosis virus (NNV) taking into consideration the role of innate immune training. Sevenband grouper primary macrophages showed an attenuated proinflammatory response and elevated antiviral response to NNV infection. In vitro, priming of β-glucan enhanced macrophage viability against NNV infection which is associated with the activation of sustained inflammatory cytokines gene expression. Observations were clear to understand that NLR Family CARD Domain Containing 3 (NLRC3) and caspase-1 activation and subsequent IL-1β production were reduced in β-glucan-primed macrophages. Subsequent markers for training including Lactate and abundance of HIF-1α were elevated in the cells following training. However, the lactate dehydrogenase (LDH) concentrations remained stable among the β-glucan stimulated infected and uninfected groups suggesting similar macrophage health in both groups. In vivo, the NNV-infected fish primed with β-glucan had a higher survival rate (60%) than the control NNV-infected group (40%). Our findings demonstrate that β-glucan induced protective responses against NNV infection and studies are underway to harness its potential applicability for prime and boost vaccination strategies.
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http://dx.doi.org/10.1016/j.fsi.2022.01.005DOI Listing
January 2022
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