Laboratory medicine最新文献

Objective: The aim of this study was to compare the performance of direct amplification of viral nucleic acid from transport medium to extracted nucleic acid for polymerase chain reaction (PCR), sequencing, and genotyping applications.

Methods: XpressAmp lysate and extracted total nucleic acid from viral transport medium containing nasopharyngeal specimens were evaluated across different molecular applications to determine performance characteristics.

Results: SARS-CoV-2 quantitative PCR and angiotensin-converting enzyme (ACE) genotyping assays worked well with XpressAmp lysate, almost equal with or better than extracted nucleic acid in some specimens. However, XpressAmp completely failed to perform in next-generation sequencing for strain typing. Both protocols failed to detect ACE2 expression in viral transport medium.

Conclusion: Direct amplification of viral nucleic acid from viral transport medium containing nasopharyngeal specimen works well for molecular assays with low thresholds of quality; however, it does have limitations with assays that require high quality nucleic acid for input. Use of the XpressAmp protocol significantly improves turnaround time and allows for easy ramp-up of PCR and genotyping assays.

Objective: To identify the TMPRSS6 gene variants in Mexican patients with iron treatment refractoriness, to describe hematological and iron profile parameters, and to use bioinformatic prediction and protein modeling tools to assess a possible biological impact for the detected missense variants.

Methods: Nineteen patients referred with iron treatment refractoriness were studied. Peripheral blood was collected to determine hematic cytometry, iron profile, hemoglobin electrophoresis, and quantification. Molecular screening was carried out for exons 15 through 18 of the TMPRSS6 gene by Sanger sequencing and for frequent thalassemia variants by amplification-refractory mutation system-polymerase chain reaction (PCR) and gap-PCR. The biological impact of the detected missense variants was assessed using bioinformatic prediction and protein modeling tools.

Results: We found 5 genetic variants in the matriptase-2 catalytic domain: 1 at intron-15/exon-16 junction (rs60484081) and 4 exonic, 3 missense (rs377054987, p.Gly626Asp; rs1384127820, p.Ser672Thr; rs855791, p.Val727Ala) and 1 synonymous (rs2235321, p.Tyr730=), with frequencies ranging from 0.18 to 0.53. No significant differences were observed in the hematological parameters or iron profile, considering type and number of variants. Bioinformatic predictions suggested a possible biological impact only for rs377054987.

Conclusions: The TMPRSS6 variants observed in Mexican patients with oral iron treatment refractoriness have high frequencies; nevertheless, their relationship with hematological and iron profile parameters needs further research. The possible biological impact for rs377054987 is due to size and amino acid hydrophobicity changes and hydrogen bond modifications.

Objective: Primary biliary cholangitis (PBC) is an autoimmune disease of liver that may be associated with other conditions, including autoimmune thyroid diseases. We aimed to investigate the frequency of anti-thyroperoxidase antibodies (TPO-Ab), antithyroglobulin antibodies (TG-Ab), and anti-thyrotropin receptor antibodies (TSHR-Ab) in Tunisian patients with PBC.

Methods: Sera of 80 patients with PBC were collected over a 9-year period. A total of 189 healthy blood donors (HBD) were included in the control group. Measurements of TPO-Ab and TG-Ab were performed using indirect enzyme-linked immunosorbent assay (ELISA). Competitive ELISA was used to assess TSHR-Ab.

Results: Antithyroid antibodies (ATA) were significantly more frequent in PBC patients than in the control group (13.7% vs 1.6%; P < 10-3). Out of 11 patients with ATA, 10 (90.9%) were female. Nine patients and 2 HBD had TPO-Ab (11.2% vs 1%; P < 10-3). TG-Ab were more frequent in patients than in healthy subjects but the difference was not statistically significant (6.2% vs 1.6%; P = .1). TPO-Ab and TG-Ab were present together in 3 patients (3.7%). TSHR-Ab were absent in patients and controls.

Conclusion: This study shows that PBC is associated with a high frequency of ATA but not TG-Ab or TSHR-Ab.

Objective: For over 60 years there has been conjecture about the identity of an Ehrlich's test positive pyrrole (Mauve Factor) reputed to be a biomarker for psychological disorders, including anxiety. We reviewed studies that attempt to identify Mauve Factor and subjected authentic standards of the 2 main candidates, kryptopyrrole and hydroxypyrrole, to the Ehrlich's reaction.

Methods: Modified Ehrlich's test for kryptopyrrole and hydroxypyrrole were applied to urine samples from 10 volunteers, anxious and nonanxious.

Results: Based on the mechanistic chemistry of Ehrlich's reaction and reactions of the 2 compounds, Mauve Factor cannot be hydroxypyrrole. Analyses of urine samples from volunteers, identified by the Generalized Anxiety Disorder - 7 item scale (GAD-7 ≥10; n = 5) and control urine samples (GAD-7 <10; n = 5) using a kryptopyrrole calibration graph, show that concentrations are similar in both groups.

Conclusion: Kryptopyrrole may be the elusive Mauve Factor. Its possible origin from stercobilin via gut microbiome-mediated metabolism, its link to gut-mediated neurological effects via γ-aminobutyric acid (GABA) receptors, and its predicted interaction with Zn2+ and consequent impact on zinc homeostasis are discussed. The GAD-7 scale does not differentiate between state and trait anxiety and as such, the minimal difference in pyrrole levels between volunteer groups requires further study.

Objective: The aim of this study was to evaluate the prognostic impact of variables, including thrombocytopenia and the amount of platelet transfusion, for predicting survival in venoarterial extracorporeal membrane oxygenation (ECMO) recipients. Additionally, we aimed to identify the predictors of increased transfusion requirement during venoarterial ECMO support.

Methods: All patients who received venoarterial ECMO between December 2008 and March 2020 were retrospectively analyzed. Univariate and multivariate Cox regressions were used to evaluate in-hospital mortality according to variables including thrombocytopenia and daily average of platelet concentrate transfusion. Stepwise multiple linear regression analysis was used to identify independent predictors for transfusion requirements.

Results: Analysis of 218 patients demonstrated severe thrombocytopenia as an independent predictor of in-hospital mortality (hazard ratio = 2.840, 95% CI: 1.593-5.063, P < .001), along with age, pre-ECMO cardiac arrest, and pH. In contrast, the amount of platelet transfusion was not associated with in-hospital mortality. Multiple variables, including the type of indication for ECMO were associated with transfusion requirements.

Conclusion: Our findings identified severe thrombocytopenia as an independent prognostic factor of in-hospital mortality. However, daily average platelet transfusion was not associated with survival outcomes. Additionally, our study identified predictive variables of increased transfusion requirements.