Biology subjects

Uyaguari, M.

Publications and source records attributed to Uyaguari, M..

3 recordsLinked to original sources

bioRxiv2024

Circulating PD-1hi CXCR5- and CXCR5+ CD4 T cells are elevated in patients with newly diagnosed Giant Cell Arteritis and predict relapse

BACKGROUNDGiant cell arteritis (GCA) is a large/medium-vessel granulomatous vasculitis, and the PD-1/PD-L1 coinhibitory pathway seems to be implicated in its pathogenesis. CD4 T cells expressing high PD-1 levels, CD4+CXCR5-PD-1hi peripheral helper (Tph) and CD4+CXCR5+PD-1hi follicular helper T cells (Tfh), are key mediators of autoimmunity. Their frequencies are elevated in the peripheral blood of subjects with several autoimmune conditions but have not been investigated in GCA. Our objective was to study the frequency of circulating Tph (cTph) and Tfh (cTfh) in patients with newly diagnosed GCA (nGCA). METHODSProspective, non-interventional study on consecutive patients referred to our ultrasound GCA fast-track clinic over a period of 24 months. Peripheral blood was drawn immediately upon initial diagnosis. For each patient, an age and gender-matched healthy control (HC) was included. PBMCs isolated by Ficoll-Hypaque were examined by cytometry. Patients were subsequently treated with standard therapy according to the updated 2018 EULAR recommendations. RESULTS65 nGCA patients were included. As compared with HC, nGCA patients presented at baseline with an increased frequency of cTph and cTfh cells. Among the 46 patients who could be followed up for 12 months, 19 experienced a relapse. The baseline frequency of cTph and cTfh cells had been significantly lower in patients who relapsed as compared with those who did not. A cTph cell frequency <0.56 predicted relapse with a sensitivity of 90% and specificity of 93%. CONCLUSIONnGCA patients demonstrate increased baseline cTph and cTfh cell frequencies. Lower baseline proportions of cTph and cTfh cells associate with relapse.

immunology↗

bioRxiv2021

Quantitation of human enteric viruses as alternative indicators of fecal pollution to evaluate wastewater treatment processes

We investigated the potential use and quantitation of human enteric viruses in municipal wastewater samples of Winnipeg (Manitoba, Canada) as alternative indicators of contamination and evaluated the processing stages of the wastewater treatment plant. During the fall 2019 and winter 2020 seasons, samples of raw sewage, activated sludge, effluents, and biosolids (sludge cake) were collected from the North End Sewage Treatment Plant (NESTP), which is the largest wastewater treatment plant in the City of Winnipeg. DNA and RNA enteric viruses, as well as the uidA gene found in Escherichia coli were targeted in the samples collected from the NESTP. Total nucleic acids from each wastewater treatment sample were extracted using a commercial spin-column kit. Enteric viruses were quantitated in the extracted samples via quantitative PCR using TaqMan assays. The average gene copies assessed in the raw sewage were not significantly different (p-values ranged between 0.0547 and 0.7986) than the average gene copies assessed in the effluents for Adenovirus and crAssphage (DNA viruses), Pepper Mild Mottle Virus (RNA virus), and uidA in terms of both volume and biomass. A significant reduction of these enteric viruses was observed consistently in activated sludge samples compared with those for raw sewage. Corresponding reductions in gene copies per volume and gene copies per biomass were also seen for uidA but were not statistically significant (p-value = 0.8769 and p-value = 0.6353, respectively). The higher gene copy numbers of enteric viruses and E. coli observed in the effluents may be associated with the 12-hour hydraulic retention time in the facility. Enteric viruses found in gene copy numbers were at least one order of magnitude higher than the E. coli marker uidA. This indicate that enteric viruses may survive the wastewater treatment process and viral-like particles are being released into the aquatic environment. Our results suggest that Adenovirus, crAssphage, and Pepper mild mottle virus can be used as complementary viral indicators of human fecal pollution.

microbiology↗

bioRxiv2019

Microbial community dynamics of surface water in British Columbia, Canada

Traditional methods for monitoring the microbiological quality of water focus on the detection of fecal indicator bacteria such as Escherichia coli, often tested as a weekly grab sample. To understand the stability of E.coli concentrations over time, we evaluated three approaches to measuring E. coli levels in water: microbial culture using Colilert, quantitative PCR for uidA and next-generation sequencing of the 16S rRNA gene. Two watersheds, one impacted by agricultural and the other by urban activities, were repeatedly sampled over a simultaneous ten-hour period during each of the four seasons. Based on 16S rRNA gene deep sequencing, each watershed showed different microbial community profiles. The bacterial microbiomes varied with season, but less so within each 10-hour sampling period. Enterobacteriaceae comprised only a small fraction (<1%) of the total community. The qPCR assay detected significantly higher quantities of E. coli compared to the Colilert assay and there was also variability in the Colilert measurements compared to Health Canadas recommendations for recreational water quality. From the 16S data, other bacteria such as Prevotella and Bacteroides showed promise as alternative indicators of fecal contamination. A better understanding of temporal changes in watershed microbiomes will be important in assessing the utility of current biomarkers of fecal contamination, determining the best timing for sample collection, as well as searching for additional microbial indicators of the health of a watershed.

microbiology↗