Thrombosis with thrombocytopenia syndrome (TTS) following adenovirus vector COVID-19 vaccination in Canada.

INTRODUCTION: Identifying and monitoring adverse events following vaccination contributed to the safety and effectiveness of COVID-19 mass vaccination campaigns. In March 2021, international reports emerged of an adverse event following vaccination with adenovirus vector COVID-19 vaccines (ChAdOx1-S [recombinant] and Ad26.COV2.S) of thrombosis with low platelet counts, referred to as thrombosis with thrombocytopenia syndrome (TTS). We described TTS reports in Canada following adenovirus vector COVID-19 vaccines and investigated whether the observed number of events were higher than expected. METHODS: Reports of TTS following receipt of ChAdOx1-S [recombinant] or Ad26.COV2.S meeting the Canadian case definition for TTS and diagnostic certainty levels 1-3 of the Brighton Collaboration case definition, submitted to the Canadian Adverse Events Following Immunization Surveillance System and Canada Vigilance Database between February 26, 2021 and October 31, 2022 were included. Demographics and characteristics of the TTS reports are described along with an analysis comparing the observed number of reports to the expected number. RESULTS: As of October 31, 2022, 56 reports of TTS following administration of ChAdOx1-S [recombinant] and no reports following Ad26.COV2.S vaccines were reported in Canada, of which 37 had functionally positive anti-PF4 antibodies. The median age was 56 years; males accounted for 54 % of reports. Five deaths were reported. The observed number of reports exceeded the expected for all ages and sexes combined, as well as for males aged 30-49 and 60-69 years, and females aged 40-59 years. CONCLUSION: Based on international surveillance data, Canada evaluated a statistical signal of TTS following adenovirus vector vaccines. The investigation of this signal demonstrated how post-market vaccine safety surveillance systems were successful in investigating rare adverse events during the rollout of COVID-19 vaccines in Canada. As adenovirus vector vaccines continue to be administered, characterization of the association between the vaccine and TTS informs immunization programs and policies.

[Rescue of injured horses, cattle and pigs from manure and cesspools by the large animal rescue service Switzerland and Liechtenstein (GTRD CH/FL)®]. / Bergung von verunfallten Pferden, Rindern und Schweinen aus Mist- und Jauchegruben durch den Grosstier­rettungsdienst Schweiz und Liechtenstein (GTRD CH/FL)®.

INTRODUCTION: One of the varied tasks of the Large Animal Rescue Service Switzerland and Liechtenstein (GTRD CH/FL)® is the recovery of animals from manure and cesspools. The aim of the present retrospective study was the evaluation of the rescue protocols of the GTRD CH/FL from such operations and the documentation of a rescue procedure. In the past 25 years, a total of 176 animals have been rescued from manure and cesspools. These included 113 cattle, 51 horses and 12 pigs. All animals could be safely rescued with the animal rescue and transport net (TBTN) or the large animal vertical rescue set (GTVBS). The TBTN is used when the opening of the cesspool is large enough to recover the animal in a horizontal position. The GTVBS is particularly suitable for narrow openings, as the recovery in a -vertical position does not require any constructional modification or the enlargement of the cesspool opening. Both rescue harnesses are characterized by reliable handling and allow gentle recovery.

INTRODUCTION: L'une des multiples tâches du Service de sauvetage des grands animaux de Suisse et du Liechtenstein (GTRD CH/FL)® est de sortir des animaux de fosses à fumier ou à lisier. Le but de la présente étude rétrospective était l'évaluation des protocoles de sauvetage du GTRD CH/FL sur la base de ces opérations et la documentation d'un processus de sauvetage. Au cours des 25 dernières années, 176 animaux au total ont été tirés de fosses à fumier ou à lisier. Il s'agissait de 113 bovins, 51 chevaux et 12 porcs. Tous les animaux ont pu être secourus en toute sécurité grâce au filet de sauvetage et de transport des animaux (TBTN) ou à l'équipement de sauvetage vertical pour grands animaux (GTVBS). Le TBTN est utilisé lorsque l'ouverture de la fosse à lisier est suffisamment grande pour récupérer l'animal en position horizontale. Le GTVBS est particulièrement adapté aux ouvertures étroites, car la récupération en position verticale permet de ne pas devoir ou modifier modifiées par d'autres mesures structurelles les ouvertures des fosses. Les deux harnais de sauvetage se caractérisent par une manipulation fiable et permettent une récupération en douceur.

Experimental discrimination of ion stopping models near the Bragg peak in highly ionized matter.

The energy deposition of ions in dense plasmas is a key process in inertial confinement fusion that determines the α-particle heating expected to trigger a burn wave in the hydrogen pellet and resulting in high thermonuclear gain. However, measurements of ion stopping in plasmas are scarce and mostly restricted to high ion velocities where theory agrees with the data. Here, we report experimental data at low projectile velocities near the Bragg peak, where the stopping force reaches its maximum. This parameter range features the largest theoretical uncertainties and conclusive data are missing until today. The precision of our measurements, combined with a reliable knowledge of the plasma parameters, allows to disprove several standard models for the stopping power for beam velocities typically encountered in inertial fusion. On the other hand, our data support theories that include a detailed treatment of strong ion-electron collisions.

Viral infections induce abundant numbers of senescent CD8 T cells.

Viral infections are often accompanied by extensive proliferation of reactive CD8 T cells. After a defined number of divisions, normal somatic cells enter a nonreplicative stage termed senescence. In the present study we have identified the inhibitory killer cell lectin-like receptor G1 (KLRG1) as a unique marker for replicative senescence of murine CD8 T cells. KLRG1 expression was induced in a substantial portion (30-60%) of CD8 T cells in C57BL/6 mice infected with lymphocytic choriomeningitis virus (LCMV), vesicular stomatitis virus, or vaccinia virus. Similarly, KLRG1 was found on a large fraction of LCMV gp33 peptide-specific TCR-transgenic (tg) effector and memory cells activated in vivo using an adoptive transfer model. Transfer experiments with CFSE-labeled TCR-tg cells into LCMV-infected hosts further indicated that induction of KLRG1 expression required an extensive number of cell divisions. Most importantly, KLRG1(+) TCR-tg effector/memory cells could efficiently lyse target cells and secrete cytokines, but were severely impaired in their ability to proliferate after Ag stimulation. Thus, this study demonstrates that senescent CD8 T cells are induced in abundant numbers during viral infections in vivo.

Break of T cell ignorance to a viral antigen in the liver induces hepatitis.

To study peripheral tolerance of CD8 T cells to a classically MHC-restricted peptide Ag expressed in hepatocytes, ALB1 transgenic (tg) mice expressing the CTL epitope GP33 of the lymphocytic choriomeningitis virus glycoprotein under control of the mouse albumin promoter were generated. ALB1 mice exclusively expressed the GP33 transgene in the liver and, at a 100- to 1000-fold lower level, in the thymus. TCR-tg mice specific for the GP33 epitope were used to directly follow GP33-specific T cells in vivo. These experiments revealed that 1) thymic expression of the GP33 transgene led to incomplete central deletion of TCR-tg cells; and 2) peripheral TCR-tg cells in ALB1 mice ignored the GP33 transgene expressed in hepatocytes. Ignorance of adoptively transferred TCR-tg cells in ALB1 mice was broken by infection with lymphocytic choriomeningitis virus, leading to induction of hepatitis in ALB1, but not in control, mice. Taken together, we have established a novel model of virus-induced CD8 T cell-mediated autoimmune hepatitis in mice and demonstrate that naive CD8 T cells may ignore Ags expressed in the liver.

Iron deficiency diminishes gallbladder neuronal nitric oxide synthase.

BACKGROUND: Iron deficiency has been demonstrated in the prairie dog to result in cholesterol crystal formation and altered biliary motility. Gallbladder filling and emptying are influenced by both inhibitory and excitatory stimuli, with nitric oxide (NO) playing a key role in normal relaxation. Iron is a cofactor for nitric oxide synthase. Therefore, we tested the hypothesis that iron deficiency would result in diminished levels of gallbladder neuronal nitric oxide synthase (nNOS) but would not influence the gallbladder's response to excitatory stimuli. MATERIALS AND METHODS: Twenty adult female prairie dogs were fed either an iron-supplemented (Fe(+)) (200 ppm) control diet (n = 10) or an iron-deficient (Fe-) (8 ppm) diet (n = 10) for 8 weeks. Fasting gallbladder volume was measured. Gallbladder muscle strips were harvested for response to excitatory stimuli and measurement of nNOS protein levels by Western blotting. Muscle strip response to a spectrum of doses of cholecystokinin, acetylcholine, and electrical field stimuli was determined, and the areas under the response curves were calculated. RESULTS: Gallbladder volume increased in the iron-deficient prairie dogs compared with the iron-supplemented group (1.45 +/- 0.27 mL vs 0.80 +/- 0.13 mL, P < 0.05). Iron deficiency diminished the ratio of gallbladder nNOS to beta-actin protein levels (0.05 +/- 0.01 vs 3.48 +/- 1.02, P < 0.05) but resulted in a normal response to excitatory stimuli. CONCLUSIONS: We conclude that diminished gallbladder neuronal nitric oxide synthase contributes to the gallbladder stasis that occurs with iron deficiency. This phenomenon may contribute to the increased incidence of gallstones in premenopausal women.

Effect of spaceflight on the isotonic contractile properties of single skeletal muscle fibers in the rhesus monkey.

Experiments from both Cosmos and Space Shuttle missions have shown weightlessness to result in a rapid decline in the mass and force of rat hindlimb extensor muscles. Additionally, despite an increased maximal shortening velocity, peak power was reduced in rat soleus muscle post-flight. In humans, declines in voluntary peak isometric ankle extensor torque ranging from 15-40% have been reported following long- and short-term spaceflight and prolonged bed rest. Complete understanding of the cellular events responsible for the fiber atrophy and the decline in force, as well as the development of effective countermeasures, will require detailed knowledge of how the physiological and biochemical processes of muscle function are altered by spaceflight. The specific purpose of this investigation was to determine the extent to which the isotonic contractile properties of the slow- and fast-twitch fiber types of the soleus and gastrocnemius muscles of rhesus monkeys (Macaca mulatta) were altered by a 14-day spaceflight.

Identification of an alpha2,6-sialyltransferase induced early after lymphocyte activation.

We have used mRNA differential display PCR to search for genes induced in activated T cells and we identified a gene encoding an alpha2,6-sialyltransferase (ST6GalNAc IV) that is rapidly induced in lymphocytes after antigen or mitogen stimulation. The 3.6 kb full-length cDNA clone (MK45) obtained contained a single open reading frame encoding a 302 amino acid protein and a 2.5 kb 3' untranslated region. MK45 expression in in vivo-activated CD8 T cells reached the highest level 4 h after antigen triggering and then declined rapidly to nearly base levels within 45 h. Northern blot analysis further revealed that MK45 expression was also induced in LPS-activated B cells and antigen-triggered CD4 T cells in vitro. MK45 expression was low or undetectable in most other mouse tissues examined, when compared to activated lymphocytes. Importantly, the mRNA expression level of other sialyltransferases remained largely unchanged during the early stage of lymphocyte activation. Finally, increased ecto-sialyltransferase activity and an altered sialylation pattern were demonstrated on the cell surface of early activated CD8 T cells. Our report identifies a candidate sialyltransferase gene that is involved in the early alteration of the sialylation pattern of cell surface molecules in activated lymphocytes.

Kinetics of the response of naive and memory CD8 T cells to antigen: similarities and differences.

We have studied the kinetics of the antigen induced response of naive and memory CD8 T cells expressing a transgenic T cell receptor (TCR) specific for the glycoprotein peptide amino acid 33-41 (GP33) of the lymphocytic choriomeningitis virus (LCMV). Memory T cells were generated in vivo by adoptive transfer of LCMV TCR transgenic T cells into normal recipient mice, followed by LCMV infection. The results demonstrated that the cell cycle progression and kinetics of TCR down-modulation, CD25 and CD69 up-regulation were identical in naive and memory T cells after antigen recognition. Moreover, the two T cell populations did not differ in respect of activation thresholds and in their proliferative capacities neither in vitro nor in vivo. However, memory CD8 T cells could be more rapidly induced to become cytolytic and to secrete high levels of interleukin-2 and interferon-gamma than naive T cells. LCMV GP33-specific CD8 memory T cells were only slightly more efficient in reducing LCMV titers in the spleen but were far more effective than naive LCMV GP33-specific T cells in controlling subcutaneous tumor growth of B16.F10 melanoma cells which expressed the LCMV GP33 epitope as tumor-associated antigen. Thus, in our experiments the main difference between CD8 memory T cells and naive cells is the ability of the former to rapidly acquire effector cell functions.

Virus-activated CD8 T cells and lymphokine-activated NK cells express the mast cell function-associated antigen, an inhibitory C-type lectin.

The mast cell function-associated Ag (MAFA) is an inhibitory C-type lectin that was originally identified on the cell surface of a rat mucosal mast cell line, RBL-2H3. We have cloned the mouse homologue of the rat MAFA gene, and Northern blot analysis revealed that mouse MAFA (mMAFA) gene expression was strongly induced in effector CD8 T cells and lymphokine-activated NK cells but not in effector CD4 T cells and in mouse mast cells. Moreover, mMAFA gene expression was only found in effector CD8 T cells that had been primed in vivo with live virus because in vitro activated CD8 T cells did not express mMAFA. Primary sequence comparison revealed a high degree of conservation (89% similarity) between rat MAFA and mMAFA. Thus, the MAFA molecule in the mouse is a putative inhibitory receptor on anti-viral CD8 T cells induced in vivo and on NK cells.

Force-velocity-power and force-pCa relationships of human soleus fibers after 17 days of bed rest.

Soleus muscle fibers from the rat display a reduction in peak power and Ca2+ sensitivity after hindlimb suspension. To examine human responses to non-weight bearing, we obtained soleus biopsies from eight adult men before and immediately after 17 days of bed rest (BR). Single chemically skinned fibers were mounted between a force transducer and a servo-controlled position motor and activated with maximal (isotonic properties) and/or submaximal (Ca2+ sensitivity) levels of free Ca2+. Gel electrophoresis indicated that all pre- and post-BR fibers expressed type I myosin heavy chain. Post-BR fibers obtained from one subject displayed increases in peak power and Ca2+ sensitivity. In contrast, post-BR fibers obtained from the seven remaining subjects showed an average 11% reduction in peak power (P < 0.05), with each individual displaying a 7-27% reduction in this variable. Post-BR fibers from these subjects were smaller in diameter and produced 21% less force at the shortening velocity associated with peak power. However, the shortening velocity at peak power output was elevated 13% in the post-BR fibers, which partially compensated for their lower force. Post-BR fibers from these same seven subjects also displayed a reduced sensitivity to free Ca2+ (P < 0.05). These results indicate that the reduced functional capacity of human lower limb extensor muscles after BR may be in part caused by alterations in the cross-bridge mechanisms of contraction.

Beta-galactoside-binding protein secreted by activated T cells inhibits antigen-induced proliferation of T cells.

We have used mRNA differential display PCR to search for genes induced in activated T cells and have found the LGALS1 (lectin, galactoside-binding, soluble) gene to be strongly up-regulated in effector T cells. The protein coded by the LGALS1 gene is a beta-galactoside-binding protein (betaGBP), which is released by cells as a monomeric negative growth factor but which can also associate into homodimers (galectin-1) with lectin properties. Northern blot analysis revealed that ex vivo isolated CD8+ effector T cells induced by a viral infection expressed high amounts of LGALS1 mRNA, whereas LGALS1 expression was almost absent in resting CD8+ T cells. LGALS1 expression could be induced in CD4+ and CD8+ T cells upon activation with the cognate peptide antigen and high levels of LGALS1 expression were found in concanavalin A-activated T cells but not in lipopolysaccharide-activated B cells. Gel filtration and Western blot analysis revealed that only monomeric betaGBP was released by activated CD8+ T cells and in vitro experiments further showed that recombinant betaGBP was able to inhibit antigen-induced proliferation of naive and antigen-experienced CD8+ T cells. Thus, these data indicate a role of betaGBP as an autocrine negative growth factor for CD8+ T cells.

Homeostatic regulation of CD8+ T cells after antigen challenge in the absence of Fas (CD95).

The role of Fas in the homeostatic regulation of CD8+ T cells after antigen challenge was analyzed in the murine model of lymphocytic choriomeningitis virus (LCMV) infection. Mice homozygous for the lpr mutation and carrying T cell receptor (TCR) alphabeta transgenes specific for the LCMV glycoprotein peptide aa 33-41 in the context of H-2Db were used. Five main results emerged: first, development of lymphadenopathy and of CD4- CD8- double-negative B220+ T cells in lpr mice was not inhibited by the alphabeta TCR transgenes; second, tolerance induction and peripheral deletion of CD8+ T cells induced by LCMV glycoprotein peptide injection was independent of Fas expression; third, clonal down-regulation of Fas-deficient TCR-transgenic CD8+ T cells after acute LCM virus infection was identical to the decline of transgenic T cells expressing Fas; fourth, in vivo activated CD8+ effector T cells from TCR transgenic and TCR-lpr/lpr mice were equally susceptible to activation-induced cell death in vitro; and fifth, transgenic effector T cells from lpr/lpr mice were cleared in the declining phase of the immune response in vivo without giving rise to CD4- CD8- double-negative T cells. Taken together, these data suggest that the homeostatic regulation of CD8+ T cells after antigen challenge in vivo is regulated by mechanisms that do not require Fas.

Isometric force and maximal shortening velocity of single muscle fibers from elite master runners.

Single chemically permeabilized gastrocnemius fibers from six elite endurance-trained master runners (RUN group) and five age-matched sedentary controls (SED group) were mounted between a force transducer and a position motor, studied under conditions of maximal and submaximal Ca2+ activation, and subsequently electrophoresed on 5% polyacrylamide gels to determine myosin heavy chain (MHC) composition. For the SED group, peak isometric tension (Pzero) averaged 143 +/- 3, 156 +/- 4, and 170 +/- 4 kN/m2 and maximal shortening velocity (Vzero) averaged 0.43 +/- 0.01, 1.90 +/- 0.08, and 5.59 +/- 0.40 fiber lengths/s for fibers expressing type I, IIa, and IIx MHC, respectively (all comparisons, P < 0.05). Hill plot analysis of relative forces during submaximal Ca2+ activation indicated no SED vs. RUN differences in Ca2+ sensitivity or in the cooperativity of Ca2+ activation. However, at maximal Ca2+ activation, RUN type I and IIa fibers produced 15% less peak absolute force than SED fibers (P < 0.05). This reduction in fiber force was a direct result of the smaller diameter of the RUN fibers (P < 0.05), because Pzero, peak elastic modulus (Ezero), and Pzero/Ezero were not different between SED and RUN groups. RUN type I fibers also displayed a mean Vzero that was 19% higher than the average Vzero of the SED type I fibers (P < 0.05). In separate experiments, quantification of relative myosin light chain (MLC) isoform content revealed a 28% greater ratio of MLC3 to MLC2 in single type I fibers from the RUN group (P < 0.05), suggesting that the elevated Vzero of the RUN type I fibers was related to a greater expression of MLC3. In conclusion, the single fibers from the elite master runners displayed specific morphological and contractile properties that may enhance the performance of these athletes during prolonged muscular activity.

Visualization, characterization, and turnover of CD8+ memory T cells in virus-infected hosts.

The cellular basis of T cell memory is a controversial issue and progress has been hampered by the inability to induce and to trace long-term memory T cells specific for a defined antigen in vivo. By using the murine model of lymphocytic choriomeningitis virus (LCMV) infection and an adoptive transfer system with CD8+ T cells from transgenic mice expressing an LCMV-specific T cell receptor, a population of authentic memory T cells specific for LCMV was generated and analyzed in vivo. The transgenic T cells that have expanded (1,000-fold) and then decreased (10-fold) in LCMV-infected C57BL/6 recipient mice exhibited the following characteristics: they were (a) of larger average cell size than their naive counterparts but smaller than day 8 effector cells; (b) heterogeneous with respect to expression of cell surface "memory" markers; and (c) directly cytolytic when isolated from recipient spleens. The time-dependent proliferative activity of these LCMV-specific memory T cells was analyzed in the recipients by bromodeoxyuridine labeling experiments in vivo. The experiments revealed that LCMV-specific CD8+ memory T cells can persist in LCMV-immune mice for extended periods of time (>2 mo) in the absence of cell division; the memory population as a whole survived beyond 11 mo.

Phylogenetic analysis of hepatitis C virus isolates from hemodialysis patients.

A high prevalence of hepatitis C virus (HCV) infection has been reported in hemodialysis patients. Main risk factors for transmission are previous blood transfusions and possibly nosocomial infections within the dialytic environment. In the present study 224 hemodialysis patients from the same department were tested for the presence of anti-HCV antibodies and HCV-RNA. The presence of anti-HCV in hemodialysis patients was correlated with a history of more than 10 blood transfusions (P = 0.001) and with a duration of hemodialysis treatment for more than 10 years (P = 0.001). The issue of possible patient-to-patient infection was addressed by sequence analysis of all HCV-RNA positive hemodialysis patients (N = 14) together with a control panel of HCV isolates from 56 unrelated non-hemodialysis patients with hepatitis C from the same geographical area. Subsequent phylogenetic analysis of nucleotide sequences obtained from the 5'-noncoding region and the nonstructural NS-5 region of the HCV genome revealed that only two hemodialysis patients were infected by a highly related HCV isolate. The remaining HCV-RNA positive hemodialysis patients including those without previous blood transfusions were all infected by phylogenetically-distant HCV isolates, providing evidence against a nosocomial transmission route. The data of the present study show that molecular epidemiological techniques are important to investigate the issue of nosocomial infection. In our hemodialysis unit patient-to-patient infection appears uncommon and draws attention towards other possible (such as, blood products such as human serum albumin, immunoglobulins) or even yet unrecognized transmission routes.

Force-velocity and power characteristics of rat soleus muscle fibers after hindlimb suspension.

The effects of 1, 2, and 3 wk of hindlimb suspension (HS) on force-velocity and power characteristics of single rat soleus fibers were determined. After 1, 2, or 3 wk of HS, small fiber bundles were isolated, placed in skinning solution, and stored at -20 degrees C until studied. Single fibers were isolated and placed between a motor arm and force transducer, functional properties were studied, and fiber protein content was subsequently analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Additional fibers were isolated from soleus of control and after 1 and 3 wk of HS, and fiber type distribution and myosin light chain stoichiometry were determined from SDS-PAGE analysis. After 1 wk of HS, percent type I fibers declined from 82 to 74%, whereas hybrid fibers increased from 10 to 18%. Percent fast type II fibers increased from 8% in control and 1 wk of HS to 26% by 3 wk of HS. Most fibers showed an increased unloaded maximal shortening velocity (Vo), but myosin heavy chain remained entirely slow type I. The mechanism for increased Vo is unknown. There was a progressive decrease in fiber diameter (14, 30, and 38%) and peak force (38, 56, and 63%) after 1, 2, and 3 wk of HS, respectively. One week of HS resulted in a shift of the force-velocity curve, and between 2 and 3 wk of HS the curve shifted further such that Vo was higher than control at all relative loads < 45% peak isometric force. Peak absolute power output of soleus fibers progressively decreased through 2 wk of HS but showed no further change at 3 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Pneumogram recordings and cerebral computed tomography as predictors of the severity of infant apnea.

We studied several predictors of severity of apnea and caretakers' anxiety about home cardiorespiratory monitoring in 476 families with infants enrolled in a perinatal follow-up program. Thirty-six (8%) of the infants had apparent life-threatening events at home. These infants were compared with the remaining infants, who had benign outcomes. Normal pneumograms and normal cerebral computed tomographic scans predicted the absence of significant respiratory problems (99% and 100% true negative rates, respectively). Infants with these signs may not require home monitoring. This study used a stringent criterion of periodic breathing (< or = 3% of quiet time) in defining a normal pneumogram. A more common criterion (< or = 10%) would have accurately predicted only 45% and missed 55% of the infants with life-threatening events. Level of caretakers' anxiety about monitoring was related to severity of apnea. Parental anxiety about monitoring may have been overestimated in previous research.