Publications by authors named "Ann Varghese"

Aim: Injudicious usage of antibiotics has led to the emergence of antibiotic resistance which is a major health-care problem in developing countries such as India. Our aim was to show how antibiotic therapy based on serial procalcitonin (PCT) assay can help in antibiotic de-escalation in septic patients.

Materials And Methods: A pre-post interventional study was conducted among 300 septic patients admitted to an intensive care unit (ICU).

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Collagen hydrolysis, catalyzed by Zn(II)-dependent matrix metalloproteinases (MMPs), is a critical physiological process. Despite previous computational investigations into the catalytic mechanisms of MMP-mediated collagenolysis, a significant knowledge gap in understanding remains regarding the influence of conformational sampling and entropic contributions at physiological temperature on enzymatic collagenolysis. In our comprehensive multilevel computational study, employing quantum mechanics/molecular mechanics (QM/MM) metadynamics (MetD) simulations, we aimed to bridge this gap and provide valuable insights into the catalytic mechanism of MMP-1.

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The opioid crisis in the United States is a significant public health issue, with a nearly threefold increase in opioid-related fatalities between 1999 and 2014. In response to this crisis, society has made numerous efforts to mitigate its impact. Recent advancements in understanding the structural intricacies of the κ opioid receptor (KOR) have improved our knowledge of how opioids interact with their receptors, triggering downstream signaling pathways that lead to pain relief.

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Biocatalytic C-H oxidation reactions are of important synthetic utility, provide a sustainable route for selective synthesis of important organic molecules, and are an integral part of fundamental cell processes. The multidomain non-heme Fe(ii)/2-oxoglutarate (2OG) dependent oxygenase AspH catalyzes stereoselective (3)-hydroxylation of aspartyl- and asparaginyl-residues. Unusually, compared to other 2OG hydroxylases, crystallography has shown that AspH lacks the carboxylate residue of the characteristic two-His-one-Asp/Glu Fe-binding triad.

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Unlabelled: The recent WHO classification of female genital tracts recommends cervical carcinomas to be further subtyped as HPV-associated and HPV-independent and accepted p16 immunoreactivity as a surrogate biomarker for HPV testing. This paper presents the clinicopathological spectrum of cervical carcinomas in correlation with p16 immunoreactivity.

Aims And Objectives: This study aims to evaluate the immunoreactivity of p16 in cervical carcinoma, subtype them into HPV-associated and HPV-independent based on p16 immunoreactivity, and correlate them with clinicopathological features.

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Human matrix metalloproteinase-1 (MMP-1) is a zinc(II)-dependent enzyme that catalyzes collagenolysis. Despite the availability of extensive experimental data, the mechanism of MMP-1-catalyzed collagenolysis remains poorly understood due to the lack of experimental structure of a catalytically productive enzyme-substrate complex of MMP-1. In this study, we apply molecular dynamics and combined quantum mechanics/molecular mechanics to reveal the reaction mechanism of MMP-1 based on a computationally modeled structure of the catalytically competent complex of MMP-1 that contains a large triple-helical peptide substrate.

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An electrocardiogram (ECG) plays a crucial role in identifying and classifying cardiac arrhythmia. Traditional methods employ handcrafted features, and more recently, deep learning methods use convolution and recursive structures to classify heart signals. Considering the time sequence nature of the ECG signal, a transformer-based model with its high parallelism is proposed to classify ECG arrhythmia.

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The front cover artwork is provided by Dr. Karabencheva-Christova's group at Michigan Technological University. The images show the initially formed and the catalytically productive conformations of MMP-1 complex with the Triple Helical Peptide (THP), the free energy profile connecting them as well as the coordination geometry of the catalytic zinc (II).

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Methylation of cytosine bases is strongly linked to gene expression, imprinting, aging, and carcinogenesis. The Ten-eleven translocation (TET) family of enzymes, which are Fe(II)/2-oxoglutarate (2OG)-dependent enzymes, employ Fe(IV)=O species to dealkylate the lesioned bases to an unmodified cytosine. Recently, it has been shown that the TET2 enzyme can catalyze promiscuously DNA substrates containing unnatural alkylated cytosine.

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Metalloproteinase-1 (MMP-1) catalyzed collagen degradation is essential for a wide variety of normal physiological processes, while at the same time contributing to several diseases in humans. Therefore, a comprehensive understanding of this process is of great importance. Although crystallographic and spectroscopic studies provided fundamental information about the structure and function of MMP-1, the precise mechanism of collagen degradation especially considering the complex and flexible structure of the substrate, remains poorly understood.

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Matrix metalloproteinase-1 (MMP-1) is a Zn(II) dependent endopeptidase involved in the degradation of collagen, the most abundant structural protein in the extracellular matrix of connective tissues and the human body. Herein we performed a multilevel computational analysis including molecular dynamics (MD), combined quantum mechanics/molecular mechanics (QM/MM), and quantum mechanics (QM) calculations to characterize the structure and geometry of the catalytic Zn(II) within the MMP-1 protein environment in comparison to crystallographic and spectroscopic data. The substrate's removal fine-tuned impact on the conformational dynamics and geometry of the catalytic Zn(II) center was also explored.

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Article Synopsis
  • The Omicron variant (B.1.1.529) of SARS-CoV-2 has many mutations that make it highly transmissible and partially able to evade neutralizing antibodies, but vaccinated individuals still have some protection against severe disease due to strong cellular immunity.
  • In a study involving healthcare workers who received three doses of the BioNTech mRNA vaccine, it was found that their B and T cell responses were enhanced against older variants but less effective against the Omicron spike protein.
  • Those previously infected with earlier variants (like Alpha) had reduced antibody responses against Omicron, while uninfected individuals who got infected with Omicron showed improved immunity to earlier variants but weaker responses against Omicron itself.
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Singlet fission (SF) is proposed as a promising method to circumvent the Shockley-Queisser threshold of single junction photovoltaics. Progress towards realizing efficient SF-based devices has been impeded by the fact that only a handful of molecules and their derivatives practically exhibit efficient SF. In the present work, we demonstrate a TDDFT-based rapid and cost-effective computational approach for designing SF chromophores by doping various atomic sites (substituting carbon atoms) of polycyclic aromatic hydrocarbons with nitrogen, phosphorus, and silicon.

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Matrix metalloproteinases (MMPs) are Zn(II) dependent endopeptidases involved in the degradation of collagen. Unbalanced collagen breakdown results in numerous pathological conditions, including cardiovascular and neurodegenerative diseases and tumor growth and invasion. Matrix metalloproteinase-1 (MMP-1) is a member of the MMPs family.

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Development of incisional hernia (IH) is multifactorial but inflammation and abdominal wall ECM (extracellular matrix) disorganization are key pathological events. We investigated if the differential expression of fibroblast biomarkers reflects the cellular milieu and the dysregulated ECM in IH tissues. Expression of fibroblast biomarkers, including connective tissue growth factor, alpha-smooth muscle actin (α-SMA), CD34 (cluster of differentiation 34), cadherin-11 and fibroblast specific protein 1 (FSP1), was examined by histology and immunofluorescence in the hernial-fascial ring/neck tissue (HRT) and hernia sack tissue (HST) harvested from the patients undergoing hernia surgery and compared with normal fascia (FT) and peritoneum (PT) harvested from brain-dead healthy subjects undergoing organ procurement for transplantation.

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Introduction: Peer-assisted learning (PAL) is a method of teaching in which students teach their often less-experienced peers. Whilst they gain more knowledge, peer tutors are able to convey information at a level that tutees can engage with. Whilst the use of PAL has increased in popularity within the healthcare faculty, there are fewer reports of its efficacy within dental education.

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Atypical teratoid rhabdoid tumour (ATRT) is a rare and highly aggressive malignant neoplasm of the central nervous system (CNS), which occurs predominantly in children less than 2 years of age. There are less than 50 cases described in adult. We report a case of primary spinal ATRT in a 65-year-old male who presented to us with cauda equina syndrome.

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