John J Rajasekaran

John J Rajasekaran


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 August 2024 in Microorganisms
Verified
Journal Article
Open access
PDF file
JRJohn J Rajasekaran
John J Rajasekaran
HKHari Krishnamurthy
Hari Krishnamurthy
JBJophi Bosco
Jophi Bosco
VJVasanth Jayaraman
Vasanth Jayaraman
KKKarthik Krishna
Karthik Krishna
KBKang Bei
Kang Bei
Purpose of review: This review investigates the oral microbiome’s composition, functions, influencing factors, connections to oral and systemic diseases, and personalized oral care strategies. Recent findings: The oral microbiome is a complex ecosystem consisting of bacteria, fungi, archaea, and viruses that contribute to oral health. Various factors, such as diet, smoking, alcohol consumption, lifestyle choices, and medical conditions, can affect the balance of the oral microbiome and lead to dysbiosis, which can result in oral health issues like dental caries, gingivitis, periodontitis, oral candidiasis, and halitosis. Importantly, our review explores novel associations between the oral microbiome and systemic diseases including gastrointestinal, cardiovascular, endocrinal, and neurological conditions, autoimmune diseases, and cancer. We comprehensively review the efficacy of interventions like dental probiotics, xylitol, oral rinses, fluoride, essential oils, oil pulling, and peptides in promoting oral health by modulating the oral microbiome. Summary: This review emphasizes the critical functions of the oral microbiota in dental and overall health, providing insights into the effects of microbial imbalances on various diseases. It underlines the significant connection between the oral microbiota and general health. Furthermore, it explores the advantages of probiotics and other dental care ingredients in promoting oral health and addressing common oral issues, offering a comprehensive strategy for personalized oral care.

28 November 2024 in Ageing Research Reviews
Verified
Journal Article
Open access
HKHari Krishnamurthy
Hari Krishnamurthy
VJVasanth Jayaraman
Vasanth Jayaraman
KKKarthik Krishna
Karthik Krishna
TWTianhao Wang
Tianhao Wang
KBKang Bei
Kang Bei
JRJohn J Rajasekaran
John J Rajasekaran
Alzheimer's disease (AD) is the most common type of dementia and neurodegenerative disease characterized by neurofibrillary tangles (NFTs) and amyloid plaque. Familial AD is caused by mutations in the APP, PSEN1, and PSEN2 genes and these mutations result in the early onset of the disease. Sporadic AD usually affects older adults over the age of 65 years and is, therefore classified as late-onset AD (LOAD). Several risk factors associated with LOAD including the APOE gene have been identified. Moreover, GWAS studies have identified a wide array of genes and polymorphisms that are associated with LOAD risk. Currently, the diagnosis of AD involves the evaluation of memory and personality changes, cognitive impairment, and medical and family history to rule out other diseases. Laboratory tests to assess the biomarkers in the body fluids as well as MRI, CT, and PET scans to analyze the presence of plaques and NFTs are also included in the diagnosis of AD. It is important to diagnose AD before the onset of clinical symptoms, i.e. during the preclinical stage, to delay the progression and for better management of the disease. Research has been conducted to identify biomarkers of AD in the CSF, serum, saliva, and urine during the preclinical stage. Current research has identified several biomarkers and potential biomarkers in the body fluids that enhance diagnostic accuracy. Aside from genetics, other factors such as diet, physical activity, and lifestyle factors may influence the risk of developing AD. Clinical trials are underway to find potential biomarkers, diagnostic measures, and treatments for AD mainly in the preclinical stage. This review provides an overview of the genes and biomarkers of AD.

19 November 2020 in PLOS ONE
Verified
Journal Article
Open access
PDF file
HKHari Krishnamurthy
Hari Krishnamurthy
VJVasanth Jayaraman
Vasanth Jayaraman
KKKarthik Krishna
Karthik Krishna
KRKarenah E. Rajasekaran
Karenah E. Rajasekaran
TWTianhao Wang
Tianhao Wang
JMJoseph A. Murray
Joseph A. Murray
Background: Antibody diagnostics play an important role in disease detection and can potentially aid in monitoring of the immune responses to see if an individual has developed immunity. Developing high throughput diagnostics which does not involve handling of infectious material becomes imperative in the case of pandemics such as the recent outbreak of SARS-CoV2. Methods: A protein microarray technology was used to detect the plurality of antibody response to four novel antigens namely S1 glycoprotein, Receptor binding domain (RBD), S2 glycoprotein and Nucleoprotein of the novel coronavirus named SARS-CoV2 using serum samples. A DBS card was additionally used to compare its performance with a venipuncture-based serum separator tube (SST) draw. Results: The three main subclasses of antibodies IgM, IgA and IgG were analyzed to see the variations in immune responses in the affected population and compared to their microbial RT-PCR based NP swab results. The clinical sensitivity and specificity were determined to be 99.67% and 99.77%. In the matrix comparison study, which would enable patients to test without risk of transmitting the virus, DBS (Dried Blood Spot) matched with higher than 98% accuracy to a venipuncture-based SST collection. Conclusion: Multiplex testing enables higher sensitivity and specificity which is essential while establishing exposure on a population scale. This flexible platform along with a discrete collection methodology would be crucial and broadly useful to scale up testing in current and future pandemics. Minimum sample volume that can be collected using DBS cards can be processed in this multiplex pillar plate format enabling the capacity to provide the reliability of high throughput analyzers while having the ease of collection similar to rapid tests.

9 June 2023 in Medicine
Verified
Journal Article
Open access
HKHari Krishnamurthy
Hari Krishnamurthy
UBUma Maheshwari Doctor Of Philosophy Balaguru
Uma Maheshwari Doctor Of Philosophy Balaguru
MPMichelle Pereira
Michelle Pereira
VJVasanth Jayaraman
Vasanth Jayaraman
QSQi Song
Qi Song
JRJohn J Rajasekaran
John J Rajasekaran
Cardiovascular diseases (CVDs) are a leading cause of death worldwide which is why early risk prediction is crucial. Discrete Polygenic risk score (PRS) measurement using saliva or dried blood spot samples collected at home poses a convenient means for early CVD risk assessment. The present study assessed the effects of 28 disease-associated single nucleotide polymorphisms (SNPs) on 16 serological cardiac markers and also aggregated the risk alleles into a PRS to evaluate its applicability in CVD-risk prediction. The study assessed genetic and serological markers in 184 individuals. The association between serological markers and individual genetic variants was evaluated using a two-tailed t test while the associations of serum markers with the PRS was analyzed using the Pearson correlation. The comparative analysis of genotypes revealed statistically significant associations between serum markers and CVD-associated SNPs with Apo B: Apo A-1, LDL Direct, Apo B, sdLDL, hsCRP, Lp(a), NT-proBNP, and PLAC levels being significantly associated with the risk alleles of the SNPs, rs12526453, rs5186, rs10911021, rs1801131, rs670, rs10757274, and rs10757278. Increased PLAC levels were associated with rs10757274 and rs10757278 (P < .05). The SNPs, rs1801133, rs1549758, rs1799983, rs5082, and rs5186 were significantly associated with an increase in the cardioprotective markers, HDL and ApoA1 (P < .05). Furthermore, the PRS was associated with increasing levels of several serum cardiac markers (r 2 > 0.6). Significant correlations were observed between high PRS and NT-proBNP and ox-LDL levels with the r 2 values being 0.82 (95% CI = 0.13–0.99; P = .03) and 0.94 (95% CI = 0.63–0.99; P = .005), respectively. The present study reports that SNPs have differential effects on serum markers with rs12526453, rs5186, rs10911021, rs1801131, rs670, rs10757274, and rs10757278 showing significant associations with elevated marker levels, which are indicators of deteriorating cardiac health. Genetic assessment via a convenient at-home collection to calculate the PRS can serve as an effective predictive tool for early CVD-risk assessment. This may help identify the risk groups that may require increased serological monitoring.

18 October 2019 in Gut Pathogens
Verified
Journal Article
Open access
PDF file
YYYuanyuan Yang
Yuanyuan Yang
VRVinod Rajendran
Vinod Rajendran
VJVasanth Jayaraman
Vasanth Jayaraman
TWTianhao Wang
Tianhao Wang
KBKang Bei
Kang Bei
HKHari Krishnamurthy
Hari Krishnamurthy
Background: Rapid detection of a wide range of etiologic agents is essential for appropriate treatment and control of gastrointestinal (GI) infections. A variety of microbial species including bacteria, viruses, parasites, and fungi have been recognized as diarrheagenic enteric pathogens. However, multiplex testing of various targets in a single reaction needs further improvement because of its limitation in species and throughput. Results: This study aims at developing and evaluating a DNA microarray-based qualitative multiplexed polymerase chain reaction (PCR) assay, Vibrant GI pathogen panel (GPP), for simultaneous detection of 27 enteric GI pathogenic targets (16 bacteria, 5 viruses, 4 parasites, and 2 fungi) directly from stool specimens. Limits of detection ranged from 102 to 104 cells/mL for bacteria, 102 to 103 cells/mL for parasites, 102 to 103 RNA copies/mL for viruses, and 102 to 103 cells/mL for fungi. Performance characteristics were determined using 27 Quantitative Genomic DNAs, 212 spiked stool specimens, 1067 clinical and archived stool specimens. Overall sensitivity was 95.9% (95% CI 92.4–98.1) and specificity was 100% (95% CI 99.9–100). Polymicrobial detections contained either two or three organisms was 20.2% (35/173) of positive clinical specimens and 3.3% (35/1055) of all clinical specimens. Conclusion: The Vibrant GPP is a comprehensive, high-throughput, and rapid DNA microarray to provide etiologic diagnosis of GI infections in the laboratory setting.

2 July 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
JRJohn J Rajasekaran
John J Rajasekaran
HKHari Krishnamurthy
Hari Krishnamurthy
JBJophi Bosco
Jophi Bosco
VJVasanth Jayaraman
Vasanth Jayaraman
KKKarthik Krishna
Karthik Krishna
KBKang Bei
Kang Bei
Purpose of review: This review investigates the oral microbiome's composition, functions, influencing factors, connections to oral and systemic diseases, and personalised oral care strategies. Recent findings: The oral microbiome is a complex ecosystem consisting of bacteria, fungi, archaea, and viruses that contribute to oral health. Various factors, such as diet, smoking, alcohol consumption, lifestyle choices, and medical conditions, can affect the balance of the oral microbiome and lead to dysbiosis, which can result in oral health issues like dental caries, gingivitis, periodontitis, oral candidiasis, and halitosis. Importantly, our review explores novel associations between the oral microbiome and systemic diseases including gastrointestinal, cardiovascular, endocrinal, neurological conditions, autoimmune diseases, and cancer. We comprehensively review the efficacy of interventions like dental probiotics, xylitol, oral rinses, fluoride, essential oils, oil pulling, and peptides in promoting oral health by modulating the oral microbiome. Summary: This review emphasizes the critical functions of the oral microbiota in dental and overall health, providing insights into the effects of microbial imbalances on various diseases. It underlines the significant connection between the oral microbiota and general health. Furthermore, it explores the advantages of probiotics and other dental care ingredients in promoting oral health and addressing common oral issues, offering a comprehensive strategy for personalized oral care.