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Researchers may implement magnetic resonance imaging (MRI) to evaluate neurophysiological metrics (e.g. connectivity) in athletes with sports-related concussion (SRC). MRI usage has been purported to exacerbate symptoms that mimic SRC symptomatology, possibly influencing recovery. The present study examined MRI use on SRC recovery outcomes in collegiate athletes. Ninety student-athletes (45 with MRI acutely post-SRC, 45 non-MRI) from four collegiate sites were analysed. Multivariable Cox proportional hazard regressions were used to measure the SRC recovery risk [return-to-play (RTP) initiation (RTP-I) and unrestricted RTP] with hazard ratios (HR) and 95% confidence intervals (95% CI). No hazard differences for median days to RTP-I [MRI: 10, interquartile range (IQR) = 7-15; non-MRI: 7 (IQR = 4-9)] were observed (HR = 0.75; 95% CI: 0.28-1.21). No hazard differences for median days to RTP [(MRI: 17 (IQR = 11-60); non-MRI: 12 (IQR = 8-24)] were observed (HR = 0.77; 95% CI: 0.29-1.26). MRI use post-SRC does not affect recovery; researchers/clinicians can employ such a procedure without affecting athlete recovery.

Various vaccines were developed to reduce the spread of the Severe Acute Respiratory Syndrome Cov-2 (SARS-CoV-2) virus. Quickly after the start of vaccination, reports emerged that anti-SARS-CoV-2 vaccines, including ChAdOx1-S, could be associated with an increased risk of thrombosis. We investigated the hemostatic changes after ChAdOx1-S vaccination in 631 health care workers. Blood samples were collected 32 days on average after the second ChAdOx1-S vaccination, to evaluate hemostatic markers such as D-dimer, fibrinogen, α2-macroglobulin, FVIII and thrombin generation. Endothelial function was assessed by measuring Von Willebrand Factor (VWF) and active VWF. IL-6 and IL-10 were measured to study the activation of the immune system. Additionally, SARS-CoV-2 anti-nucleoside and anti-spike protein antibody titers were determined. Prothrombin and fibrinogen levels were significantly reduced after vaccination (-7.5% and -16.9%, p < 0.0001). Significantly more vaccinated subjects were outside the normal range compared to controls for prothrombin (42.1% vs. 26.4%, p = 0.026) and antithrombin (23.9% vs. 3.6%, p = 0.0010). Thrombin generation indicated a more procoagulant profile, characterized by a significantly shortened lag time (-11.3%, p < 0.0001) and time-to-peak (-13.0% and p < 0.0001) and an increased peak height (32.6%, p = 0.0015) in vaccinated subjects compared to unvaccinated controls. Increased VWF (+39.5%, p < 0.0001) and active VWF levels (+24.1 %, p < 0.0001) pointed toward endothelial activation, and IL-10 levels were significantly increased (9.29 pg/mL vs. 2.43 pg/mL, p = 0.032). The persistent increase of IL-10 indicates that the immune system remains active after ChAdOx1-S vaccination. This could trigger a pathophysiological mechanism causing an increased thrombin generation profile and vascular endothelial activation, which could subsequently result in and increased risk of thrombotic events., Competing Interests: BL, RdL-K, MR, DH, and MN are employees of Synapse Research Institute, part of Diagnostica Stago. HC received funding for research from Bayer and Pfizer; compensation fees for consultancy and advisory boards from Daaichi, Pfizer, Leo, Bayer, Galapagos, Anthos, Alexion, and Alveron; shareholder from Coagulation profile; all benefits were transferred to the CARIM institute to support investigator-initiated research. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 de Laat, Stragier, de Laat-Kremers, Ninivaggi, Mesotten, Thiessen, Van Pelt, Roest, Penders, Vanelderen, Huskens, De Jongh, Laenen, Fivez, ten Cate, Heylen, Heylen and Steensels.)

Background and Objectives: To determine whether primitive reflexes serve as an indicator of dementia in adults with Down syndrome (DS), we collected neurologic examination data, cognitive and behavioral assessments, and clinical consensus diagnoses of dementia from 92 adults with DS., Methods: In a cross-sectional, observational study of a regional cohort, χ 2 and Fisher exact tests examined individual reflexes across the diagnostic group (no, possible, or probable dementia). In 64 participants with all 8 reflexes assessed, the number of primitive reflexes was assessed as a predictor of diagnosis using age-controlled multinomial logistic regression and of performance on clinical assessments (Brief Praxis Test [BPT], Severe Impairment Battery [SIB], and the Dementia Questionnaire for People with Learning Disabilities [DLD]) using age-adjusted linear regression., Results: Primitive palmomental, grasp, snout, and suck reflexes were more frequent in individuals with probable dementia, but all participants showed at least 1 primitive reflex. Multiple primitive reflexes in combination served as a better indicator of dementia, with each additional abnormal reflex tripling probability of the probable dementia group membership controlling for age. Abnormal reflex count was not associated with direct assessment of cognition and praxis (SIB and BPT) but associated with informant ratings of cognitive and behavioral functioning (DLD)., Discussion: The presence of multiple reflexes serves as an indicator of dementia status in DS as a supplement to direct assessment of cognition and praxis. The reflex examination may serve as a tool in the multimethod evaluation for dementia in DS, as it appears unaffected by intellectual disability and language mastery., (© 2021 American Academy of Neurology.)

Background: Buprenorphine-naloxone (BUP) initiation in emergency departments improves follow-up and survival among patients with opioid use disorder. We aimed to assess self-reported BUP-related practices and attitudes among emergency physicians., Methods: We designed a cross-sectional physician survey by adapting a validated questionnaire on opioid harm reduction practices, attitudes and barriers. We recruited physician leads from 6 Canadian provinces to administer surveys to the staff physicians in their emergency department groups between December 2018 and November 2019. We included academic and community non-locum emergency department staff physicians. We excluded responses from emergency department groups with response rates less than 50% to minimize nonresponse bias. Primary (BUP prescribing practices) and secondary (willingness and attitudes) outcomes were analyzed using descriptive statistics., Results: After excluding 1 group for low response (9/26 physicians), 652 of 798 (81.7%) physicians responded from 22 groups serving 34 emergency departments. Among respondents, 64.1% (95% confidence interval [CI] 60.4%-67.8%, emergency department group range 7.1%-100.0%) had prescribed BUP at least once in their career, 38.4% had prescribed it for home initiation and 24.8% prescribed it at least once a month. Overall, 68.9% (95% CI 65.3%-72.4%, emergency department group range 24.1%-97.6%) were willing to administer BUP, 64.2% felt it was a major responsibility and 37.1% felt they understood people who use drugs. Respondents most frequently rated lack of adequate training (58.2%) and lack of time (55.2%) as very important barriers to BUP initiation., Interpretation: Two-thirds of the emergency physicians surveyed prescribed BUP, although only one-quarter did so regularly and one-third prescribed it for home initiation; wide variation between emergency department groups existed. Strategies to increase BUP initiation must address physicians' lack of time and training for BUP initiation and improve their understanding of people who use drugs., Competing Interests: Competing interests: None declared., (© 2021 CMA Joule Inc. or its licensors.)

Vitamin K deficiency bleeding (VKDB) in infants still occurs despite worldwide use of prophylaxis. Clinical manifestations can be dramatic with over 50% of patients presenting with intracranial haemorrhage and a mortality rate of 20% in late vitamin K deficiency bleeding. Special attention should be given to infants with a high risk profile (preterm, breast feeding, cholestasis, malabsorption). A tentative diagnosis can be made observing quick normalisation of some easy-to-perform haemostatic parameters (PT, aPTT) after administration of vitamin K. Nowadays, VKDB can still be the first clinical sign of diseases causing malabsorption of fat-soluble vitamins. In this case report, VKDB led to the diagnosis of cystic fibrosis, the most common fatal autosomal recessive disease among Caucasian people.

Several studies have suggested that the cyclin-dependent kinase (CDK) inhibitor p21 plays a crucial role in regulating hematopoietic stem and progenitor pool size. To allow assessment of long-term stem cell functioning in vivo, we have backcrossed a p21 null allele to C57BL/6 (B6) mice, the most commonly used mouse strain in hematopoietic stem cell research. In various in vitro assays, the homozygous deletion of the p21 allele did not affect the number of hematopoietic cells in B6 mice. Furthermore, the competitive repopulation ability was not different between p21-deficient and wild-type stem cells from both young and aged (20-month-old) mice. These results show that p21 is not essential for regulation of stem cell number in steady state. When proliferative stress was applied on p21-deficient stem cells by serial transplantation of 1,500 Lin(-)Sca-1(+)c-kit(+) (LSK) cells, again no detrimental effect was observed on cobblestone area-forming cell (CAFC) frequency and competitive repopulating ability. However, when bone marrow cells from mice that received 2 Gy of irradiation were transplanted, p21 deficiency resulted in a more than fourfold reduction in competitive repopulation index. Finally, we did not find major differences in cell cycle status and global gene expression patterns between LSK cells from p21-deficient and wild-type mice. Our findings indicate that the background of mice used for studying the function of a gene by genetic modification may determine the outcome. Cumulatively, our data fail to support the notion that p21 is essential for stem cell function during steady-state hematopoiesis, but may be relatively more important under conditions of cellular stress.

The haematopoietic system is a complex organised tissue with a hierarchical structure. Identification of organisational pathways within the haematopoietic system is relevant for a better understanding of haematopoiesis in health and disease. We have analysed numerous haematopoietic parameters in two panels of a total of 157 genetically distinct B6AKRF2 mice, derived from an intercross between AKR and C57Bl/6 mice, strains known to differ in various stem cell traits. The major objective of our study was to assess the extent to which various haematopoietic parameters, such as stem cell numbers, progenitor cell cycling, progenitor cell mobilisation and neutrophil numbers in blood and bone marrow are coregulated. The genotypes of these mice were used to search for genetic loci that regulate these parameters. We found significant quantitative trait loci (QTL) associated with the number of stem cells (CAFC-35) in the bone marrow and the number of neutrophils in the blood. However, most haematopoietic parameters appeared to be controlled by non-heritable (epigenetic) factors, or by multiple QTLs. Our study reveals striking differences in structure of the haematopoietic hierarchy between individual mice. Surprisingly, stem and progenitor cell pool size and proliferation rate, as well as peripheral blood cell counts are all independently regulated.

Objective: Hematopoietic stem cells (HSC) are considered to display a quiescent state with low turnover rate. We investigated the cell-cycle kinetics of HSC after a single dose of cytarabine (Ara-C)., Materials and Methods: We analyzed by flow cytometry the cell-cycle status of lin(low)sca-1(+)c-kit(+) (LSK) stem cells isolated from the bone marrow of C57Bl/6 mice sacrificed at 0, 2, 4, 6, 8, 12, 20, 48, 72, and 96 hours after intraperitoneal injection of Ara-C (100 mg/kg) using 7-aminoactinomycin-D (7-AAD) for DNA staining. In vivo bromodeoxyuridine (BrdU) incorporation and Ki-67 expression in HCS were also measured., Results: Two hours after administration of Ara-C, LSK cells ceased to incorporate BrdU. At 4 hours, a decrease of S-phase cells from 10% at baseline to 4% was found (p < 0.05), followed by a rapid increase of BrdU and 7-AAD incorporation reaching a maximum of 28% S-phase cells at 20 hours (p < 0.001). Ki-67 expression suggested recruitment of 20% of cells from G0 into cell cycle. The total number of LSK cells increased 2.5-fold within this short time interval. After 72 hours, a recovery of cell cycling to baseline levels was observed., Conclusion: This data shows that a single injection of Ara-C first rapidly induced S-phase arrest in HSC for up to 4 hours. Subsequently, an unexpectedly rapid activation of HCS with recruitment of G0 cells into cell cycle was observed. The mechanism of cell-cycle activation of LSK cells remains unknown, but reduction of the number of differentiated end cell did not appear to be the primary trigger.