Annual (2023) taxonomic update of RNA-directed RNA polymerase-encoding negative-sense RNA viruses (realm Riboviria: kingdom Orthornavirae: phylum Negarnaviricota)

55 Pág.In April 2023, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by one new family, 14 new genera, and 140 new species. Two genera and 538 species were renamed. One species was moved, and four were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.This work was supported in part through the Laulima Government Solutions, LLC, prime contract with the U.S. National Institute of Allergy and Infec tious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC, under Contract No. HHSN272201800013C. U.J.B. was supported by the Division of Intramural Resarch, NIAID. This work was also funded in part by Contract No. HSHQDC15-C-00064 awarded by DHS S and T for the management and operation of The National Biodefense Analysis and Countermeasures Centre, a federally funded research and development centre operated by the Battelle National Biodefense Institute (V.W.); and NIH contract HHSN272201000040I/HHSN27200004/D04 and grant R24AI120942 (N.V., R.B.T.). S.S. acknowl edges support from the Mississippi Agricultural and Forestry Experiment Station (MAFES), USDA-ARS project 58-6066-9-033 and the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch Project, under Accession Number 1021494. The funders had no role in the design of the study; in the collection, analysis, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of the Army, the U.S. Department of Defence, the U.S. Department of Health and Human Services, including the Centres for Disease Control and Prevention, the U.S. Department of Homeland Security (DHS) Science and Technology Directorate (S and T), or of the institutions and companies affiliated with the authors. In no event shall any of these entities have any responsibility or liability for any use, misuse, inability to use, or reliance upon the information contained herein. The U.S. departments do not endorse any products or commercial services mentioned in this publication. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S.Government retains a non-exclusive, paid up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes.Peer reviewe

A Paced Auditory Serial Addition Task evokes stress and differential effects on masseter-muscle activity and haemodynamics.

This study aimed to determine autonomic and jaw-muscle activities, and haemodynamic responses, to acute experimental mental stress in humans. Eleven healthy men (25.2 ± 3.0 years of age) and five healthy women (23.0 ± 3.7 years of age) performed a standardized mental stress task, the Paced Auditory Serial Addition Task (PASAT). Autonomic function, such as heart rate variability (HRV), and haemodynamic changes were recorded simultaneously. The success rate of the PASAT decreased with increased pace and duration. Low-frequency (5.8 ± 1.1 ms(2)) and high-frequency (5.3 ± 0.6 ms(2)) components of HRV decreased during the PASAT (to 5.0 ± 0.9 ms(2) and 4.6 ± 1.1 ms(2), respectively) as an indication of acute stress. Oxygenated haemoglobin in the masseter muscle (14.6 ± 2.2 10(4) units mm(-3)) remained at an elevated level during the PASAT (15.5 ± 2.5 10(4) units mm(-3)), whereas deoxygenated haemoglobin (7.8 ± 2.3 10(4) units mm(-3)) showed a consistent decrease (to 6.8 ± 2.1 10(4) units mm(-3)). Total haemoglobin and jaw-muscle electromyographic (EMG) activity did not change during the PASAT. Thus, PASAT-induced mental stress changed the parasympathetic/sympathetic balance of the heart and had an acute influence on jaw-muscle haemodynamics, but not on jaw-muscle EMG activity. This non-invasive experimental set-up can be applied to study the effects of repeated or longer-lasting mental stress in order to further the understanding of pathophysiological mechanisms in craniofacial pain conditions

Choice of biomaterials : Do soft occlusal splints influence jaw-muscle activity during sleep? A preliminary report

Aim: The choice of biomaterials for occlusal splints may significantly influence biological outcome. In dentistry, hard acrylic occlusal splints (OS) have been shown to have a temporary and inhibitory effect on jaw-muscle activity, such as tooth clenching and grinding during sleep, i.e., sleep bruxism (SB). Traditionally, this inhibitory effect has been explained by changes in the intraoral condition rather than the specific effects of changes in-occlusion. The aim of this preliminary study was to investigate the effect of another type of occlusal surface, such as a soft-material OS in addition to a hard-type OS in terms of changes in jaw-muscle activity during sleep. Materials and Methods: Seven healthy subjects (mean ± SD, six men and one woman: 28.9 ± 2.7 year old), participated in this study. A soft-material OS (ethylene vinyl acetate copolymer) was fabricated for each subject and the subjects used the OS for five continuous nights. The EMG activity during sleep was compared to baseline (no OS). Furthermore, the EMG activity during the use of a hard-type OS (Michigan-type OS, acrylic resin), and hard-type OS combined with contingent electrical stimulation (CES) was compared to baseline values. Each session was separated by at least two weeks (washout). Jaw-muscle activity during sleep was recorded with single-channel ambulatory devices (GrindCare, MedoTech, Herlev, Denmark) in all sessions for five nights. Results: Jaw-muscle activity during sleep was 46.6 ± 29.8 EMG events / hour at baseline and significantly decreased during the hard-type OS (17.4 ± 10.5, P = 0.007) and the hard-type OS + CES (10.8 ± 7.1, P = 0.002), but not soft-material OS (36.3 ± 24.5, P = 0.055). Interestingly, the soft-material OS (coefficient of variance = 98.6 ± 35.3%) was associated with greater night-to-night variations than baseline (39.0 ± 11.8%) and the hard-type OS + CES (53.3 ± 13.7%, P < 0.013). Conclusion: The present pilot study in small sample showed that a soft-material occlusal splint does not seem to inhibit jaw-muscle activity during sleep. Within the limitation of the study, it appears that the choice of biomaterials for occlusal splints may have a significant impact on the neurobiological regulation of jaw-muscle activity during sleep

Site-to-site variation of muscle activity and sensitivity in the human anterior temporalis muscle: Implications for contingent stimulation

Objective: To evaluate variation of electromyographic (EMG) activity and sensitivity between different sites of anterior temporalis (AT) muscle. Materials and methods: Sixteen healthy subjects (eight men: 28.8 ± 5.2 year old and eight women: 29.1 ± 3.9) participated in one experimental session. EMG activity during masticatory muscle contraction was recorded from nine sites at the AT muscle in a 3 x 3 grid with 1 cm between. The subjects maintained steady 30% of maximal voluntary contraction (MVC) using visual feedback. The surface EMG electrode was moved sequentially between these nine test sites and the contractions were repeated. One site was tested four times to assess test-retest variability. The sensory threshold to electrical stimulation and impedance was also measured at the same sites as the placement of EMG electrodes. Results: The 30% MVC force values did not differ between sites (p = 0.863) or within the same site (p = 0.995) due to the feedback. The EMG activity during 30% MVC was highest at the anterior-superior site (p < 0.05) with a marginal difference within the same site (p = 0.044). Impedance was higher at the posterior-superior, posterior-middle, and posterior-inferior sites (p < 0.05). The sensory threshold was highest at the posterior-superior site (p < 0.05). Conclusions: These findings showed that electrodes close to the hairline have higher impedance and sensory thresholds and should be avoided. The anterior-superior site produces the highest EMG activity and lower sensory thresholds and can be recommended as the optimal site to place the electrode for contingent stimulation

Does restriction of mandibular movements during sleep influence jaw-muscle activity?

AIM: To investigate the effect of restriction of mandibular movements during sleep on jaw-muscle activity. MATERIALS AND METHODS: Eleven healthy subjects (four men, seven women; mean age 25.9 ± 3.1 years) with self-reports and clinical indications of sleep-bruxism participated in three randomized sessions with three different types of oral appliances: 1) a full-arch maxillary and mandibular appliances which did not allow any mandibular movement, i.e., restrictive oral appliance (ROA), 2) full-arch maxillary and mandibular oral appliances (MMOA) with no restrictions of mandibular movements, and 3) a conventional full-arch flat stabilization appliance, i.e., maxillary oral appliance (MOA). Baseline recordings of jaw-muscle activity during sleep without any oral appliance were performed and followed by one week of nightly use of the oral appliances. After the baseline recording, subjects did three sessions with oral appliance during sleep. During the last night in each session, jaw-muscle activity was recorded and compared to baseline values. A detection threshold of 10 % of maximal voluntary clenching was used to analyze the electromyographic (EMG) activity from both sides of the masseter muscles and in accordance with published criteria (Lavigne et al. 1996). RESULTS: All subjects completed the experimental protocol. Regarding to the average of left and right sides, jaw-muscle activity expressed as number of EMG episodes per hour sleep was significantly lower during MOA (5.2 ± 1.1 episodes/h) compared to baseline values (6.7 ± 1.2, P < 0.01). Furthermore, the number of EMG bursts per hour sleep was significantly lower for ROA (28.3 ± 5.0 bursts/h) and MOA (25.0 ± 6.8) compared to baseline values (40.9 ± 7.7, P < 0.05). The number of phasic EMG episodes and bursts (ROA: 1.5 ± 0.4 episodes/h and 14.8 ± 2.8 bursts/h, MMOA: 1.9 ± 0.3 and 17.7 ± 4.0, MOA: 1.5 ± 0.5 and 15.1 ± 4.7) especially decreased for all three types of appliances compared to baseline (3.0± 0.5 and 29.2 ± 5.8, P < 0.05). CONCLUSION: The results indicated that restriction of mandibular movements with oral appliances may not have major influence on jaw-muscle activity during sleep but rather that the immediate effect of any combination of oral appliances lead to a suppression of EMG bursts per hour of sleep