Publications by authors named "Elena Nikonova"

Significance: Autofluorescence characteristics of the reduced nicotinamide adenine dinucleotide and oxidized flavin cofactors are important for the evaluation of the metabolic status of the cells. The approaches that involve a detailed analysis of both spectral and time characteristics of the autofluorescence signals may provide additional insights into the biochemical processes in the cells and biological tissues and facilitate the transition of spectral fluorescence lifetime imaging into clinical applications.

Aim: We present the experiments on multispectral fluorescence lifetime imaging with a detailed analysis of the fluorescence decays and spectral profiles of the reduced nicotinamide adenine dinucleotide and oxidized flavin under a single excitation wavelength aimed at understanding whether the use of multispectral detection is helpful for metabolic imaging of cancer cells.

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Heterogeneity of tumor metabolism is an important, but still poorly understood aspect of tumor biology. Present work is focused on the visualization and quantification of cellular metabolic heterogeneity of colorectal cancer using fluorescence lifetime imaging (FLIM) of redox cofactor NAD(P)H. FLIM-microscopy of NAD(P)H was performed in vitro in four cancer cell lines (HT29, HCT116, CaCo2 and CT26), in vivo in the four types of colorectal tumors in mice and ex vivo in patients' tumor samples.

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Muscles undergo developmental transitions in gene expression and alternative splicing that are necessary to refine sarcomere structure and contractility. CUG-BP and ETR-3-like (CELF) family RNA-binding proteins are important regulators of RNA processing during myogenesis that are misregulated in diseases such as Myotonic Dystrophy Type I (DM1). Here, we report a conserved function for Bruno 1 (Bru1, Arrest), a CELF1/2 family homolog in Drosophila, during early muscle myogenesis.

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The extracellular matrix (ECM), in which collagen is the most abundant protein, impacts many aspects of tumor physiology, including cellular metabolism and intracellular pH (pHi), as well as the efficacy of chemotherapy. Meanwhile, the role of collagen in differential cell responses to treatment within heterogeneous tumor environments remains poorly investigated. In the present study, we simultaneously monitored the changes in pHi and metabolism in living colorectal cancer cells in vitro upon treatment with a chemotherapeutic combination, FOLFOX (5-fluorouracil, oxaliplatin and leucovorin).

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Motivation: Alternative splicing (AS) of introns from pre-mRNA produces diverse sets of transcripts across cell types and tissues, but is also dysregulated in many diseases. Alignment-free computational methods have greatly accelerated the quantification of mRNA transcripts from short RNA-seq reads, but they inherently rely on a catalog of known transcripts and might miss novel, disease-specific splicing events. By contrast, alignment of reads to the genome can effectively identify novel exonic segments and introns.

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Mammalian spermatozoa are highly energized cells in which most of the proteins and activated signaling cascades are involved in the metabolic pathways. Flavin adenine dinucleotide (FAD) has one of the most important roles in the correct functional activity of spermatozoa since it acts as a cofactor for flavoenzymes, critical for proper metabolism and predominantly located in mitochondria. Non-invasive, vital and non-traumatic examination of sperm FAD level and microenvironment could be performed by fluorescence lifetime imaging microscopy (FLIM).

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We aimed to assess the influence of professional dental prophylaxis on the translucency and color stability of a novel simplified shade nanohybrid composite material. Sixty composite disks (5 mm in diameter and 2 mm thick) of light ( = 30) and dark ( = 30) shades were prepared. The specimens were randomly divided into the following three groups ( = 10) according to the prophylaxis procedure used: ultrasonic scaling, air-powder polishing with sodium bicarbonate, and controls.

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The extracellular matrix (ECM) plays an important role in regulation of many aspects of tumor growth and response to therapies. However, the specifics of the interaction of chemotherapeutic agents with cancer cells in the presence of collagen, the major component of ECM, is still poorly investigated. In this study, we explored distribution of doxorubicin (DOX) and its effects on cancer cells' metabolism in the presence of collagen with different structures in 3D models.

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Molecular, morphological, and physiological heterogeneity is the inherent property of cells which governs differences in their response to external influence. Tumor cell metabolic heterogeneity is of a special interest due to its clinical relevance to tumor progression and therapeutic outcomes. Rapid, sensitive, and noninvasive assessment of metabolic heterogeneity of cells is a great demand for biomedical sciences.

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Protein isoform transitions confer muscle fibers with distinct properties and are regulated by differential transcription and alternative splicing. RNA-binding Fox protein 1 (Rbfox1) can affect both transcript levels and splicing, and is known to contribute to normal muscle development and physiology in vertebrates, although the detailed mechanisms remain obscure. In this study, we report that Rbfox1 contributes to the generation of adult muscle diversity in Rbfox1 is differentially expressed among muscle fiber types, and RNAi knockdown causes a hypercontraction phenotype that leads to behavioral and eclosion defects.

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The proper regulation of RNA processing is critical for muscle development and the fine-tuning of contractile ability among muscle fiber-types. RNA binding proteins (RBPs) regulate the diverse steps in RNA processing, including alternative splicing, which generates fiber-type specific isoforms of structural proteins that confer contractile sarcomeres with distinct biomechanical properties. Alternative splicing is disrupted in muscle diseases such as myotonic dystrophy and dilated cardiomyopathy and is altered after intense exercise as well as with aging.

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Migrating cells need to coordinate distinct leading and trailing edge dynamics but the underlying mechanisms are unclear. Here, we combine experiments and mathematical modeling to elaborate the minimal autonomous biochemical machinery necessary and sufficient for this dynamic coordination and cell movement. RhoA activates Rac1 via DIA and inhibits Rac1 via ROCK, while Rac1 inhibits RhoA through PAK.

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Animals possess a wide variety of muscle types that support different kinds of movements. Different muscles have distinct locations, morphologies and contractile properties, raising the question of how muscle diversity is generated during development. Normal aging processes and muscle disorders differentially affect particular muscle types, thus understanding how muscles normally develop and are maintained provides insight into alterations in disease and senescence.

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Drosophila flight muscle is a powerful model to study diverse processes such as transcriptional regulation, alternative splicing, metabolism, and mechanobiology, which all influence muscle development and myofibrillogenesis. Omics data, such as those generated by mass spectrometry or deep sequencing, can provide important mechanistic insights into these biological processes. For such approaches, it is beneficial to analyze tissue-specific samples to increase both selectivity and specificity of the omics fingerprints.

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Animals require different types of muscle for survival, for example for circulation, motility, reproduction and digestion. Much emphasis in the muscle field has been placed on understanding how transcriptional regulation generates diverse types of muscle during development. Recent work indicates that alternative splicing and RNA regulation are as critical to muscle development, and altered function of RNA-binding proteins causes muscle disease.

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Objective: The purpose of this study was to characterize intraoperative palatal lengthening with the modified Furlow cleft palatal repair and to determine whether lengthening correlated with preoperative cleft width, cleft type, or operating surgeon.

Design: Retrospective study.

Setting: Academic tertiary care pediatric hospital.

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Background: In Alzheimer's disease, there are striking changes in CSF composition that relate to altered choroid plexus (CP) function. Studying CP tissue gene expression at the blood-cerebrospinal fluid barrier could provide further insight into the epithelial and stromal responses to neurodegenerative disease states.

Methods: Transcriptome-wide Affymetrix microarrays were used to determine disease-related changes in gene expression in human CP.

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Introduction: Treatment guidelines recommend a stepwise approach to glycemia management in patients with type 2 diabetes (T2D), but this may result in uncontrolled glycated hemoglobin A1c (HbA1c) between steps. This retrospective analysis compared clinical and economic outcomes among patients with uncontrolled T2D initiating two oral antidiabetes drugs (OADs), glucagon-like peptide-1 receptor agonists (GLP-1 RAs), or basal insulin in a real-world setting.

Methods: Adults with T2D on OAD monotherapy were identified in the MarketScan claims database (2007-2014).

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Objective: This study evaluated the effect of lorcaserin 10 mg twice daily (LOR BID), or with phentermine 15 mg once daily (LOR BID + PHEN QD) and 15 mg twice daily (LOR BID + PHEN BID), in conjunction with energy restriction on food cravings.

Methods: Two hundred and thirty-five patients without diabetes but with obesity or overweight and ≥ 1 comorbidity received LOR BID, LOR BID + PHEN QD, or LOR BID + PHEN BID for 12 weeks in a randomized double-blind study. The Food Craving Inventory (FCI) and the Control of Eating Questionnaire (COEQ) were administered over 12 weeks.

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Objective: Assess efficacy, hypoglycemia, and weight gain in patients with type 2 diabetes (T2D) treated with insulin glargine 300 U/mL (Gla-300) or 100 U/mL (Gla-100) across different age groups.

Methods: Pooled data were generated for patients randomized to Gla-300 or Gla-100 in the EDITION 2 (NCT01499095) and 3 (NCT01676220) studies. In 4 age groups (<55, ≥55 to <60, ≥60 to <65, ≥65 years), glycated hemoglobin A1C (A1C), percentage of patients reaching A1C <7.

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Aims: This post hoc assessment evaluated the efficacy and safety of once-daily, prandial glucagon-like peptide-1 receptor agonist lixisenatide in patients with type 2 diabetes (T2D) and normal renal function (estimated glomerular filtration rate ≥90 mL/min), or mild (60-89 mL/min) or moderate (30-59 mL/min) renal impairment.

Methods: Patients from 9 lixisenatide trials in the GetGoal clinical trial programme were categorized by baseline creatinine clearance: normal renal function (lixisenatide n = 2094, placebo n = 1150); renal impairment (mild: lixisenatide n = 637, placebo n = 414; moderate: lixisenatide n = 122, placebo n = 68). Meta-analyses of placebo-adjusted mean differences between baseline renal categories were performed for efficacy and safety outcomes.

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Study Objective: To assess differences in gene expression in cholinergic basal forebrain cells between sleeping and sleep-deprived mice sacrificed at the same time of day.

Methods: Tg(ChAT-eGFP)86Gsat mice expressing enhanced green fluorescent protein (eGFP) under control of the choline acetyltransferase (Chat) promoter were utilized to guide laser capture of cholinergic cells in basal forebrain. Messenger RNA expression levels in these cells were profiled using microarrays.

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Article Synopsis
  • Non-photochemical quenching (NPQ) is crucial for light tolerance in photosynthetic organisms like cyanobacteria, where it involves light-harvesting complexes and specific proteins like the orange carotenoid protein (OCP).
  • A biophysical model was developed to analyze the interactions between light-harvesting complexes (phycobilisomes), OCP, and fluorescence recovery protein (FRP), allowing for detailed insights into their dynamics and concentrations in cells.
  • The study revealed that while higher OCP levels are needed for effective quenching in vitro, the in vivo balance shifts due to greater phycobilisome concentration, emphasizing the complex regulatory mechanisms of NPQ in cyanobacteria.
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Objective: Lorcaserin, a 5-HT receptor agonist approved for chronic weight management, is also associated with improvements in glycemic parameters in patients with/without type 2 diabetes mellitus (T2DM), but the extent to which these effects are mediated by weight loss is unknown. This post hoc analysis further examines glycemic data from the Phase III BLOOM-DM study stratified by weight changes.

Methods: Patients with T2DM were randomized to lorcaserin 10 mg twice daily or placebo.

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Purpose: Gene therapy (GT) has offered immense hope to individuals who are visually impaired because of RPE65 mutations. Although GT has shown great success in clinical trials enrolling these individuals, evidence for stability and durability of this treatment over time is still unknown. Herein we explored the value of functional magnetic resonance imaging (fMRI) as an objective measure to assess independently the longevity of retinal GT.

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