Publications by authors named "Koval J"

Total proctocolectomy with ileal pouch anal anastomosis is the standard of care for patients with severe ulcerative colitis. We generated a cell-type-resolved transcriptional and epigenetic atlas of ileal pouches using scRNA-seq and scATAC-seq data from paired biopsy samples of the ileal pouch and the ileal segment above the pouch (pre-pouch) from patients (male=4, female=2), and paired biopsies of the terminal ileum and ascending colon from healthy individuals (male=3, female=3) serving as reference. Our study finds an additional population of absorptive and secretory epithelial cells within the pouch but not the pre-pouch.

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Crohn's disease (CD) is a complex inflammatory bowel disease resulting from an interplay of genetic, microbial, and environmental factors. Cell-type-specific contributions to CD etiology and genetic risk are incompletely understood. Here we built a comprehensive atlas of cell-type- resolved chromatin accessibility comprising 557,310 candidate cis-regulatory elements (cCREs) in terminal ileum and ascending colon from patients with active and inactive CD and healthy controls.

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Objective: To assess whether a 12-week, professionally facilitated, asynchronous online support group would reduce sexual distress (primary outcome) and improve sexual function, body image, depression symptoms, relationship satisfaction, and social support (secondary outcomes) in women treated for gynecologic cancer.

Methods: Participants were 398 women recruited from three Canadian provinces and one American cancer center in cohorts of 40. Participants were randomized (50:50 odds) to either the immediate treatment condition (ITC) or the waitlist control condition (WCC).

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Gyrophoric acid (GA), a lichen secondary metabolite, has attracted more attention during the last years because of its potential biological effects. Until now, its effect in vivo has not yet been demonstrated. The aim of our study was to evaluate the basic physicochemical and pharmacokinetic properties of GA, which are directly associated with its biological activities.

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Tetracyclines serve as broad-spectrum antibiotics to treat bacterial infections. The discovery of new tetracycline resistance genes has led to new questions about the underlying mechanisms of resistance, gene transfer, and their relevance to human health. We tracked changes in the abundance of a 55-kbp conjugative transposon (CTn214) carrying a tetracycline resistance gene, within a metagenome-assembled genome derived from shotgun sequencing of microbial DNA extracted from the ileal pouch of a patient with ulcerative colitis.

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Bile acids (BAs) are cholesterol-derived molecules that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence physiology of the gut microbiota. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate BAs to other amine classes.

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Total proctocolectomy with ileal pouch anal anastomosis is the standard of care for patients with severe ulcerative colitis. We generated a cell-type-resolved transcriptional and epigenetic atlas of ileal pouches using scRNA-seq and scATAC-seq data from paired biopsy samples of the ileal pouch and the ileal segment above the pouch (pre-pouch) from patients (male=4, female=2), and paired biopsies of the terminal ileum and ascending colon from healthy individuals (male=3, female=3) serving as reference. Our study finds previously uncharacterized populations of absorptive and secretory epithelial cells within the pouch but not the pre-pouch.

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Bile acids (BAs) are cholesterol-derived molecules that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence physiology of the gut microbiota. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate BAs to other amine classes.

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This project examined e-cigarette use among Elementary School (ES) (grades 7 and 8) and Secondary School (SS) (grades 9-12) students in Ontario, Canada, for 2017 and 2019 and relationships with sociodemographic variables and traditional cigarette use. The data came from the Ontario Student Drug Use and Health Survey OSDUHS (2017, 2019). Socio-demographics included grade, school performance, sex, race, years in Canada, living arrangements and language spoken at home.

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Even in the setting of optimal resuscitation in high-income countries severe sepsis and septic shock have a mortality of 20-40%, with antibiotic resistance dramatically increasing this mortality risk. To develop a reference dataset enabling the identification of common bacterial targets for therapeutic intervention, we applied a standardized genomic, transcriptomic, proteomic and metabolomic technological framework to multiple clinical isolates of four sepsis-causing pathogens: Escherichia coli, Klebsiella pneumoniae species complex, Staphylococcus aureus and Streptococcus pyogenes. Exposure to human serum generated a sepsis molecular signature containing global increases in fatty acid and lipid biosynthesis and metabolism, consistent with cell envelope remodelling and nutrient adaptation for osmoprotection.

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Article Synopsis
  • Myelodysplastic neoplasms (MDS) and chronic myelomonocytic leukemia (CMML) are diseases caused by mutations in blood stem cells that affect blood production.
  • Hypomethylating agents (HMAs) can help manage these conditions without needing to eliminate all mutated cells, possibly improving the function of the remaining stem cells.
  • The study analyzed the mutations in different blood cell types before and after treatment to understand how these mutated stem cells behave and contribute to better blood counts following HMA therapy.
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Increasing use and mining of antimony (Sb) has resulted in greater concern involving its fate and transport in the environment. Antimony(V) and (III) are the two most environmentally relevant oxidation states, but little is known about the redox transitions between the two in natural systems. To better understand the behavior of antimony in anoxic environments, the redox transformations of Sb(V) were studied in biotic and abiotic reactors.

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Endangered species are grouped into genetically discrete populations to direct conservation efforts. Mitochondrial control region (mtCR) haplotypes are used to elucidate deep divergences between populations, as compared to nuclear microsatellites that can detect recent structuring. When prior populations are unknown, it is useful to subject microsatellite data to clustering and/or ordination population inference.

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Background & Aims: Inflammatory bowel diseases (IBD) are chronic inflammatory disorders where predictive biomarkers for the disease development and clinical course are sorely needed for development of prevention and early intervention strategies that can be implemented to improve clinical outcomes. Since gut microbiome alterations can reflect and/or contribute to impending host health changes, we examined whether gut microbiota metagenomic profiles would provide more robust measures for predicting disease outcomes in colitis-prone hosts.

Methods: Using the interleukin (IL) 10 gene-deficient (IL10 KO) murine model where early life dysbiosis from antibiotic (cefoperozone [CPZ]) treated dams vertically transferred to pups increases risk for colitis later in life, we investigated temporal metagenomic profiles in the gut microbiota of post-weaning offspring and determined their relationship to eventual clinical outcomes.

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In preceding efforts, we demonstrated that antibiotic (ABX) cocktail-mediated perturbations of the gut microbiome in two independent transgenic lines, termed APP/PS1 and APPPS1-21, leads to a reduction in Aβ deposition in male mice. To determine whether these observed reductions of cerebral Aβ amyloidosis are specific to any individual antibiotic or require the synergistic effects of several antibiotics, we treated male APPPS1-21 transgenic mice with either individual ABX or an ABX cocktail and assessed amyloid deposition. Specifically, mice were subject to oral gavage with high dose kanamycin, gentamicin, colistin, metronidazole, vancomycin, individually or in a combination (ABX cocktail) from postnatal days (PND) 14 to 21, followed by ad libitum, low-dose individual ABX or ABX cocktail in the drinking water until the time of sacrifice.

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Background: Humber River Hospital has implemented a real-time location system (RTLS) within the operating room in order to provide real-time information about patients' status and manage the many components involved during the perioperative journey.

Objective: The aim of this study was to explore both physicians' and family members' perceptions of the functionality and efficiency of the RTLS within the perioperative environment.

Methods: Semi-structured interviews were conducted with physicians and patients' family members to elicit various perspectives regarding the use of RTLSs throughout the perioperative process.

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Increases in acute hepatitis C virus (HCV) incidence may be a result of the rising prevalence of injection drug use and the opioid epidemic. Among persons who inject drugs, sharing of needles/syringes is less common and leads to a smaller proportion of incident cases than does sharing of injection drug preparation equipment. In Canada and Europe, hydromorphone controlled release has been associated with frequent reuse and sharing of IDPE.

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A combination of biochemical, biophysical and biological techniques was used to study calf thymus DNA interaction with newly synthesized 7-MEOTA-tacrine thiourea 12-17 and urea heterodimers 18-22, and to measure interference with type I and II topoisomerases. Their biological profile was also inspected in vitro on the HL-60 cell line using different flow cytometric techniques (cell cycle distribution, detection of mitochondrial membrane potential dissipation, and analysis of metabolic activity/viability). The compounds exhibited a profound inhibitory effect on topoisomerase activity (e.

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Research has shown that tobacco users have an increased risk of collisions compared to nonsmokers. Studies from 1967 through 2013 documented a crude relative risk of collision involvement of about 1.5 among smokers compared to nonsmokers.

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Sustained observations of microbial dynamics are rare, especially in southern hemisphere waters. The Australian Marine Microbial Biodiversity Initiative (AMMBI) provides methodologically standardized, continental scale, temporal phylogenetic amplicon sequencing data describing Bacteria, Archaea and microbial Eukarya assemblages. Sequence data is linked to extensive physical, biological and chemical oceanographic contextual information.

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Purpose: To examine the characteristics of the midstream urine microbiome in adults with stage 3-5 non-dialysis-dependent chronic kidney disease (CKD).

Methods: Patients with non-dialysis-dependent CKD (estimated glomerular filtration rate [eGFR] < 60 ml/min/1.73 m) and diuretic use were recruited from outpatient nephrology clinics.

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Microbial communities that inhabit environments such as soil can contain thousands of distinct taxa, yet little is known about how this diversity is maintained in response to environmental perturbations such as changes in the availability of carbon. By utilizing aerobic substrate arrays to examine the effect of carbon amendment on microbial communities taken from six distinct environments (soil from a temperate prairie and forest, tropical forest soil, subalpine forest soil, and surface water and soil from a palustrine emergent wetland), we examined how carbon amendment and inoculum source shape the composition of the community in each enrichment. Dilute subsamples from each environment were used to inoculate 96-well microtiter plates containing triplicate wells amended with one of 31 carbon sources from six different classes of organic compounds (phenols, polymers, carbohydrates, carboxylic acids, amines, amino acids).

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Article Synopsis
  • Researchers studied the properties of IgA antibodies produced by intestinal plasma cells, discovering that these antibodies are not highly specific but rather polyreactive to a wide range of gut microbiota.
  • They found that these polyreactive IgAs are developed from naïve B cells and selected in Peyer's patches, a part of the gut, without influence from bacteria or diet.
  • The study indicates that the immune system has a natural way of generating these broad-reacting IgAs, which help maintain balance with gut microbiota.
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Flow-mediated dilation (FMD) is calculated as the greatest percent change in arterial diameter following an ischaemic challenge. This Traditional %FMD calculation is thought to have statistical bias towards baseline diameter (D ), which is reduced by allometric scaling. This study examined whether allometric scaling FMD influenced the difference between a group of healthy young and older adults compared to the Traditional %FMD, and to determine whether a New (allometric) scaling %FMD improved the ability to obtain individually scaled FMD.

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Background: Hypericin-mediated photodynamic therapy (HY-PDT) has recently captured increased attention as an alternative minimally invasive anticancer treatment, although cancer cells may acquire resistance. Therefore, combination treatments may be necessary to enhance HY-PDT efficacy. Histone deacetylase inhibitors (HDACis) are often used in combination treatments due to their non-genotoxic properties and epigenetic potential to sensitize cells to external stimuli.

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