Publications by authors named "N Ravi"

243 Publications

CRISPR/Cas based gene editing: marking a new era in medical science.

Mol Biol Rep 2021 Jun 18. Epub 2021 Jun 18.

Centre for Stem Cell Research (a Unit of inStem, Bengaluru), Christian Medical College Campus, Bagayam, Vellore, 632002, Tamil Nadu, India.

CRISPR/Cas9 system, a bacterial adaptive immune system developed into a genome editing technology, has emerged as a powerful tool revolutionising genome engineering in all branches of biological science including agriculture, research and medicine. Rapid evolution of CRISPR/Cas9 system from the generation of double strand breaks to more advanced applications on gene regulation has made the wide-spread use of this technology possible. Medical science has benefited greatly from CRISPR/Cas9; being both a versatile and economical tool, it has brought gene therapy closer to reality. In this review, the development of CRISPR/Cas9 system, variants thereof and its application in different walks of medical science- research, diagnostics and therapy, will be discussed.
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http://dx.doi.org/10.1007/s11033-021-06479-7DOI Listing
June 2021

Tissue architecture delineates field cancerization in BRAFV600E-induced tumor development.

Dis Model Mech 2021 Jun 4. Epub 2021 Jun 4.

Sahlgrenska Center for Cancer Research, Institute of Biomedicine, University of Gothenburg, SE-40530, Göteborg, Sweden.

Cancer cells hijack developmental growth mechanisms but whether tissue morphogenesis and architecture modify tumorigenesis is unknown. Here, we characterized a new mouse model of sporadic thyroid carcinogenesis based on inducible expression of BRAFV600E from the thyroglobulin promoter (TgCreERT2). Spontaneous activation of this Braf-mutant allele due to leaky CRE activity revealed that intrinsic properties of thyroid follicles determined BRAF-mutant cell fate. Papillary thyroid carcinomas developed multicentrically within a normal microenvironment. Each tumor originated from a single follicle that provided a confined space for growth of a distinct tumor type. Lineage tracing revealed oligoclonal tumor development in infancy and early selection of BRAFV600E kinase inhibitor-resistant clones. Somatic mutations were few, non-recurrent, and limited to advanced tumors. Female mice developed larger tumors than males, reproducing the gender difference of human thyroid cancer. These data indicate that BRAFV600E-induced tumorigenesis is spatiotemporally regulated depending on the maturity and heterogeneity of follicles. Moreover, thyroid tissue organization seems to determine whether a BRAF-mutant lineage becomes a cancerized lineage. The sporadic thyroid cancer model provides a new tool to evaluate drug therapy at different stages of tumor evolution.
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http://dx.doi.org/10.1242/dmm.048887DOI Listing
June 2021

Descending necrotising mediastinitis: how a sore throat can result in purulent peritonitis.

BMJ Case Rep 2021 May 24;14(5). Epub 2021 May 24.

Department of General and Upper GI Surgery, St James Hospital, Dublin, Ireland.

This is a rare case of descending necrotising mediastinitis (DNM) that originated as an oropharyngeal infection, before spreading caudally to include all compartments of the mediastinum and the peritoneum beyond. The mediastinitis was treated early and aggressively with drainage, lavage and debridement in conjunction with broad-spectrum antimicrobial treatment. This case includes a right cervical incision, and a seldom needed surgical laparotomy approach to address the intra-abdominal involvement, and necessity of peritoneal washout. Following a prolonged Intesive Care Unit (ICU) stay and antibiotic course as well as other interventions detailed, the patient made a remarkable recovery and was discharged 101 days post presentation. This report goes on to discuss the rapidly evolving, life-threatening nature of DNM as well as providing an overview of possible management options, outlining how we think such cases should be approached and the clinical suspicion required in a deteriorating patient.
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http://dx.doi.org/10.1136/bcr-2021-242145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8149320PMC
May 2021

Effect of head down tilt on heart rate variability.

J Family Med Prim Care 2021 Jan 30;10(1):439-442. Epub 2021 Jan 30.

Department of Physiology, AIIMS, Bhopal, Madhya Pradesh, India.

Context: Sirshasan is supposed to increase blood flow to the brain and considered to be beneficial for intellectual function, however mastering these techniques may be difficult.

Aims: To see the effect of headstand using a tilt table on heart rate variability (HRV).

Settings And Design: A cross-sectional study that was done on 26 healthy volunteers.

Methods And Material: HRV was assessed in the supine position and 30° head tilt position for 5 min. HRV recording was done on the power lab (AD Instruments P Ltd, Castle Hill Australia). The tilt table used was Medica Podium, New Delhi, HLT-200.

Statistical Analysis Used: Paired -test.

Results: All the HRV parameters showed non-significant change except low-frequency parameters which showed significant change during head tilt.

Conclusions: Headstand to a 30° using tilt table cause a decrease in the autonomic activity which is mainly because of decrease in sympathetic activity.
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http://dx.doi.org/10.4103/jfmpc.jfmpc_1642_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8132816PMC
January 2021

Pediatric non-urgent emergency department visits and prior care-seeking at primary care.

BMC Health Serv Res 2021 May 17;21(1):466. Epub 2021 May 17.

UPMC Children's Hospital of Pittsburgh, 4401 Penn Avenue,AOB - Suite 5400, Pittsburgh, PA, 15224, USA.

Background: We aimed to examine how caregiver perceptions of primary care affects care-seeking prior to pediatric non-urgent ED visits.

Methods: We performed a cross-sectional survey of caregivers of children presenting to a pediatric ED during weekday business hours and triaged as low acuity. We first compared caregiver sociodemographic characteristics, perceptions of primary care, and stated preference in care sites (ED vs PCP) for caregivers who had sought care from their child's PCP office versus had not sought care from their child's PCP office prior to their ED visit. We then examined odds of having sought care from their PCP office prior to their ED visit using multivariable logistic regression models sequentially including caregiver primary care perceptions and stated care site preferences along with caregiver sociodemographic characteristics.

Results: Of 140 respondents, 64 (46%) sought care from their child's PCP office prior to presenting to the ED. In unadjusted analysis, children insured by Medicaid or CHIP, caregivers identifying as Black, and caregivers with lower educational attainment were less likely to have sought PCP care before presenting to the ED (p < 0.005, each). Caregivers who had sought PCP care were more likely to prefer their PCP relative to the ED in terms of ease of travel, cost, and wait times (p < 0.001, all). When including these stated preferences in a multivariable model, child insurance, caregiver race, and caregiver education were no longer significantly associated with odds of having sought PCP care prior to their ED visit.

Conclusions: Differential access to primary care may underlie observed demographic differences in non-urgent pediatric ED utilization.
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http://dx.doi.org/10.1186/s12913-021-06480-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8128083PMC
May 2021