Recombination pattern of the TCR γ locus in human peripheral T-cell lymphomas

The recombination events of the γ and β T-cell receptor (TCR) loci were analysed in a series of 39 peripheral T-cell lymphomas (PTCLs) in association with the expression of TCR chains. In TCR αβ PTCLs, 22/23 cases showed a γ-gene rearrangement while only 18/23 showed a concomitant β-gene rearrangement. The germline configuration of the β locus was found in angioimmunoblastic lymphadenopathy and lymphoepithelioid lymphomas. Three γδ PTCLs rearranged both γ and β genes. TCR silent PTCLs showed three different patterns of γ- and β-gene rearrangements. Three cases were in germline configuration for both loci; five cases had a rearranged γ and a germline β locus; and five cases had the two loci rearranged. Regarding the variable genes in the γ-rearranged alleles, members of the VγI subgroup were the most frequently presented (39/50), followed by VγII, VγIII, and VγIV (9/50, 1/50, and 1/50, respectively). Joining segment usage was as follows: J1 or J2 (32/50), JP1 or JP2 (17/50), and JP (1/50). Taken together, these data demonstrate that the γ locus is more frequently rearranged whatever the TCR expression. The γ-locus analysis provides a better diagnostic yield than the β locus in the study of PTCL clonality.     

Clinical manifestations and outcomes of coronavirus disease-19 in heart transplant recipients: a multicentre case series with a systematic review and meta-analysis

Available data on clinical presentation and mortality of coronavirus disease-2019 (COVID-19) in heart transplant (HT) recipients remain limited. We report a case series of laboratory-confirmed COVID-19 in 39 HT recipients from 3 French heart transplant centres (mean age 54.4 ± 14.8 years; 66.7% males). Hospital admission was required for 35 (89.7%) cases including 14/39 (35.9%) cases being admitted in intensive care unit. Immunosuppressive medications were reduced or discontinued in 74.4% of the patients. After a median follow-up of 54 (19–80) days, death and death or need for mechanical ventilation occurred in 25.6% and 33.3% of patients, respectively. Elevated C-reactive protein and lung involvement ≥50% on chest computed tomography (CT) at admission were associated with an increased risk of death or need for mechanical ventilation. Mortality rate from March to June in the entire 3-centre HT recipient cohort was 56% higher in 2020 compared to the time-matched 2019 cohort (2% vs. 1.28%, P = 0.15). In a meta-analysis including 4 studies, pre-existing diabetes mellitus (OR 3.60, 95% CI 1.43–9.06, I² = 0%, P = 0.006) and chronic kidney disease stage III or higher (OR 3.79, 95% CI 1.39–10.31, I² = 0%, P = 0.009) were associated with increased mortality. These findings highlight the aggressive clinical course of COVID-19 in HT recipients.     

T cell antigenicity and immunogenicity of allogeneic exosomes

Extracellular vesicles, including exosomes, are regularly released by allogeneic cells after transplantation. Recipient antigen-presenting cells (APCs) capture these vesicles and subsequently display donor MHC molecules on their surface. Recent evidence suggests that activation of alloreactive T cells by the so-called cross-dressed APCs plays an important role in initiating the alloresponse associated with allograft rejection. On the other hand, whether allogeneic exosomes can bind to T cells on their own and activate them remains unclear. In this study, we showed that allogeneic exosomes can bind to T cells but do not stimulate them in vitro unless they are cultured with APCs. On the other hand, allogeneic exosomes activate T cells in vivo and sensitize mice to alloantigens but only when delivered in an inflammatory environment.     

Prevalence of HIV and sexually transmitted and blood-borne infections,and related preventive and risk behaviours,among gay,bisexual and other men who have sex with men in Montreal,Toronto and Vancouver: results from the Engage Study

ObjectivesThe last Canadian biobehavioural surveillance study of HIV and other sexually transmitted and blood-borne infections (STBBI) among gay, bisexual and other men who have sex with men (GBM) was conducted in 2010. We designed a study to measure STBBI prevalence among GBM in metropolitan Montreal, Toronto and Vancouver and to document related preventive and risk behaviours.MethodsThe Engage Cohort Study used respondent-driven sampling (RDS) to recruit GBM who reported sex with another man in the past 6 months. At baseline, we examined recruitment characteristics of the samples, and the RDS-II-adjusted distributions of socio-demographics, laboratory-confirmed HIV and other STBBI prevalence, and related behaviours, with a focus on univariate differences among cities.ResultsA total of 2449 GBM were recruited from February 2017 to August 2019. HIV prevalence was lower in Montreal (14.2%) than in Toronto (22.2%) or Vancouver (20.4%). History of syphilis infection was similar across cities (14–16%). Vancouver had more HIV-negative/unknown participants who reported never being HIV tested (18.6%) than Toronto (12.9%) or Montreal (11.5%). Both Montreal (74.9%) and Vancouver (78.8%) had higher proportions of men who tested for another STBBI in the past 6 months than Toronto (67.4%). Vancouver had a higher proportion of men who used pre-exposure prophylaxis (PrEP) in the past 6 months (18.9%) than Toronto (11.1%) or Montreal (9.6%).ConclusionThe three largest cities of Canada differed in HIV prevalence, STBBI testing and PrEP use among GBM. Our findings also suggest the need for scale-up of both PrEP and STI testing among GBM in Canada.     

Mucoadhesion of Latexes. I. Analytical Methods and Kinetic Studies

A Fourier transform infrared spectroscopy/attenuated total reflection technique for direct quantification of adsorbed poly(styrene) latexes on rat intestinal mucosa was developed for deposited latex amounts up to 1.5 g/m². The method agreed well with another dosage assay of adsorbed particles by turbidimetry after denaturation of the mucus. Adsorption kinetics were made under static conditions at latex concentrations of 4 g/L in physiological saline. Ninety percent of equilibrium was reached after 10 min for a particle size of 230 nm, 20 min for a size of 320 nm, and 30 min for a size of 670 nm. The plateaus were between 0.6 and 0.9 g/m² (adsorbed mass per apparent surface of mucosa). The first phase of the kinetics was theoretically approached by a diffusion model in the suspension medium. Mucosa from rat jejunum and ileum could be considered as a homogeneous biological model for latex adsorption.     

Treatment of post-operative nausea and vomiting: comparison of propofol,droperidol and metoclopramide

Purpose  

To compare the efficacy of propofol in a subhypnotic dose (10 mg iv), droperidol (1.25 mg iv), or metoclopramide (10 mg iv) in the treatment of PONV in the post anaesthesia care unit (PACU).     

Temporal and spatial variation in the amount of cadmium in the phantom midge larvae (Chaoborus spp.)

Several factors, including body size, age, and temporal and spatial variation, which may influence the amount of cadmium (Cd) in the phantom midge larvae, Chaoborus spp., were examined in eight lakes, four from south-central Ontario (Dorset Region) and four from northwestern Ontario (Experimental Lakes Area). All three species of Chaoborus (C. punctipennis, C. trivittatus, C. flavicans) found in Chub Lake (south-central Ontario), were analyzed seasonally. One species, C. punctipennis, was collected and analyzed from all lakes.Smaller Chaoborus tended to have higher Cd concentrations (g Cd/g dry weight), and lower Cd burdens (ng Cd/Animal) than larger Chaoborus. The Cd concentrations of Chaoborus in Chub Lake were lowest during the summer, which coincided with the fastest growth of the organisms. The Cd burdens differed between species, which was attributed to differences in their asynchronous life histories.Cadmium burdens and concentrations were significantly lower in the organisms from northwestern Ontario than those from south-central Ontario. Lower atmospheric deposition rates, lower Cd concentrations in the lake water, as well as life history differences, may explain these results.     

Dyke Award. The search for human telencephalic ventriculofugal arteries

Our study traced the vascular development of the fetal telencephalon in the last two trimesters of gestation and the first 15 years of life in 60 fetal and childhood brains. We filled the macro- and microvascular beds with Microfil and made stereoscopic observations of cleared 0.5- to 1.0-cm-thick sections. Separately, we identified developing vascular structures histologically. In our youngest specimen (16-weeks gestation), transcerebral channels with walls consisting of a single layer of endothelium and varying in diameter from 10 to 50 microns originated from leptomeningeal arteries and veins at right angles to the surface and passed through the cortical plate (future cortex). They branched at varying depths within the mantle and germinal matrix surrounding the lateral ventricles. At deeper levels the channels freely anastomosed with each other. A cortical microvascular network did not appear until 22 to 24 weeks. The new endothelial channels were derived from leptomeningeal vessels and from larger transcerebral channels. Most regions of isocortex developed a microvascular plexus simultaneously, regardless of degree of maturation. Striatal channels matured earlier than extrastriatal channels, having developed a muscularis to within 100 microns of the ganglionic eminence by 22- to 24-weeks gestation. Maturation of the vascular walls of extrastriatal channels into proper arteries and veins occurred during the first postnatal year. Anastomotic channels were present throughout the leptomeningeal, striatal, and extrastriatal regions in all of our specimens from 16 weeks gestation to 15 years old. Our study does not support the existence of ventriculofugal arteries and deep white matter arterial border zones in the human fetus and neonate, which have been postulated to be the basis of "periventricular" leukomalacia.