EMG analysis while using a smartphone

The purpose of this study was to clarify the influence of different postures on the activity of the shoulder girdle and lower back muscles while using a smartphone. Sixteen healthy male participants maintained two postures while using a smartphone : a good posture in which the tragus and acromion were closer to the vertical line passing through the greater trochanter, and a poor posture in which the tragus and acromion were farther from the vertical line passing through the greater trochanter. The target muscles were the rhomboid major (Rhom), upper trapezius, middle trapezius, lower trapezius (LT), lumbar erector spinae (LES), and lumbar multifidus (LMF). The activities of the Rhom and LT were significantly lower with poor posture than those with good posture. The activities of LES and LMF were significantly higher with poor posture than those with good posture. The results of this study indicated that poor posture was associated with hypoactivity of the shoulder girdle muscles and hyperactivity of the lower back muscles when compared with good posture. Poor posture for prolonged periods while using a smartphone would lead to malfunction of the shoulder girdle muscles and musculofascial lower back pain

EMG activity during 2000 m rowing

This study aimed to clarify the changes in the activity of the trunk and lower limb muscles during 2000-m rowing. Ten male rowers performed a 2000-m race simulation on a rowing ergometer. Electromyography results of the abdominal muscles, back muscles, gluteus maximus (GMax), biceps femoris (BF), and rectus femoris (RF) were recorded. The electromyographic activity during the three strokes after the start (initial stage), at 1000m (middle stage), and before the end (final stage) were analyzed. From the handle position, the rowing motion was divided into five phases (early-drive, middle-drive, late-drive, early-recovery, and late-recovery). The peak activities of the abdominal muscles, back muscles, GMax, and BF in each stroke of the rowing motion were delayed at the middle and final stages compared to the initial stage (P < 0.05). The peak activity of the RF was observed in the late-drive phase at the initial stage, whereas a high RF activity was observed in the middle-drive phase at the middle and final stages (P < 0.05). Considering the results of the activity of the back muscles and RF, RF muscular endurance enhancement may lead to a decrease in the load on the back muscles and help prevent muscular low back pain in rowers

Effectiveness of mRNA COVID-19 vaccines against symptomatic SARS-CoV-2 infections during the SARS-CoV-2 Omicron BA.1 and BA.2 epidemic in Japan: vaccine effectiveness real-time surveillance for SARS-CoV-2 (VERSUS)

Background: Evaluating COVID-19 vaccine effectiveness (VE) domestically is crucial for assessing and determining national vaccination policy. This study aimed to evaluate VE of mRNA COVID-19 vaccines in Japan. Methods: We conducted a multicenter test-negative case-control study. The study comprised indivi-duals aged ≥16 visiting medical facilities with COVID-19-related signs or symptoms from 1 January to 26 June 2022, when Omicron BA.1 and BA.2 were dominant nationwide. We evaluated VE of primary and booster vaccination against symptomatic SARS-CoV-2 infections and relative VE of booster compared with primary.Results: We enrolled 7,931 episodes, including 3,055 test positive. The median age was 39, 48.0% were male, and 20.5% had underlying medical conditions. In individuals aged 16 to 64, VE of primary vaccination within 90 days was 35.6% (95% CI, 19.0–48.8%). After booster, VE increased to 68.7% (60.6–75.1%). In individuals aged ≥65, VE of primary and booster was 31.2% (−44.0–67.1%) and 76.5% (46.7–89.7%), respectively. Relative VE of booster compared with primary vaccination was 52.9% (41.0– 62.5%) in individuals aged 16 to 64 and 65.9% (35.7–81.9%) in individuals aged ≥65.Conclusions: During BA.1 and BA.2 epidemic in Japan, mRNA COVID-19 primary vaccination provided modest protection. Booster vaccination was necessary to protect against symptomatic infections

In silico design of novel probes for the atypical opioid receptor MRGPRX2

The primate-exclusive MRGPRX2 G protein-coupled receptor (GPCR) has been suggested to modulate pain and itch. Despite putative peptide and small molecule MRGPRX2 agonists, selective nanomolar potency probes have not yet been reported. To identify a MRGPRX2 probe, we first screened 5,695 small molecules and found many opioid compounds activated MRGPRX2, including (−)- and (+)-morphine, hydrocodone, sinomenine, dextromethorphan and the prodynorphin-derived peptides, dynorphin A, dynorphin B, and α- and β-neoendorphin. We used these to select for mutagenesis-validated homology models and docked almost 4 million small molecules. From this docking, we predicted ZINC-3573, which represents a potent MRGPRX2-selective agonist, showing little activity against 315 other GPCRs and 97 representative kinases, and an essentially inactive enantiomer. ZINC-3573 activates endogenous MRGPRX2 in a human mast cell line inducing degranulation and calcium release. MRGPRX2 is a unique atypical opioid-like receptor important for modulating mast cell degranulation, which can now be specifically modulated with ZINC-3573

Pneumatosis intestinalis with a benign clinical course: a report of two cases

Abstract Background Pneumatosis intestinalis (PI) is a rare condition characterized by the presence of gas within the gastrointestinal tract wall. Most cases of PI have a benign clinical course, although some have serious outcomes. Mechanical stress on or bacterial infection of the gastrointestinal tract wall may be responsible for the onset of PI, but the detailed mechanism of PI pathogenesis is still unclear. Here, we describe two Japanese patients presenting with benign PI. Case presentation Case 1, a 37-year-old previously healthy male patient, had a 1-week history of abdominal pain, and case 2, a 78-year-old female diabetic patient, had a 2-week history of voglibose treatment and abdominal pain. Intramural gas was mainly distributed in the colon in case 1 and in the small intestine in case 2. Interestingly, neither patient showed obvious inflammatory signs upon admission and recovered spontaneously with conservative treatment, including fasting and fluid infusion without antibiotics. Voglibose treatment was terminated in case 2. Recent studies have shown the presence of nonpathogenic bacteria, such as Clostridium spp., in PI lesions, which usually play an important role in modulating the tolerance of the gastrointestinal immune responses. The benign clinical course and spontaneous resolution of PI in these patients, without specific treatment, suggests that nonpathogenic indigenous bacteria in the gastrointestinal tract participate in the pathogenesis of PI. Conclusion In patients with benign PI, the absence of an inflammatory response and the spontaneous resolution of the disease without specific treatment suggest the participation of nonpathogenic indigenous bacteria of the gastrointestinal tract

Validation of anterior ankle soft tissue dynamics and shear modulus for anterior ankle impingement syndrome after ankle fracture surgery

Abstract Anterior ankle impingement syndrome (AAIS) has been reported to account for a high percentage of complications following ankle fracture surgery. The soft tissue etiology of AAIS is thought to be thickening and inflammation of the anterior ankle soft tissues intervening anteriorly at the tibiotalar joint, causing pain and functional limitation during dorsiflexion. However, the effects of anterior ankle soft tissue dynamics and stiffness on AAIS have yet to be clarified. This study aimed to determine the relationship between AAIS and the anterior ankle soft tissue thickness change ratio and shear modulus using ultrasonography (US). The participants were 20 patients with ankle joint fractures (AO classification A, B) who had undergone open reduction and internal fixation and 20 healthy adults. The evaluation periods were 3 months and 6 months postoperatively. US was used to delineate the tibialis anterior tendon, extensor hallucis longus tendon, and the extensor digitorum longus tendon over the talus and tibia on a long-axis image. Anterior ankle soft tissue thickness was measured as the shortest distance from the most convex part of the talus to the tendon directly above it. The Anterior ankle soft tissue thickness change ratio was determined by dividing the value at 0° dorsiflexion by the value at 10° plantarflexion. The same images as for the anterior soft tissue thickness measurement were drawn for the shear modulus measurement, and the average shear modulus (kPa) was calculated using shear-wave elastography. There was no significant difference in the thickness change ratio between the postoperative and healthy groups. Compared with the healthy group, the shear modulus was significantly higher at 3 and 6 months in the postoperative group (p < 0.01). The shear elastic modulus at 6-month postoperative group was significantly lower than at 3-month postoperative group (p < 0.01). Anterior ankle joint soft tissue stiffness may increase after surgery for an ankle fracture

Differences and relationships between weightbearing and non-weightbearing dorsiflexion range of motion in foot and ankle injuries

Abstract Background This study aimed to: (1) identify assessment methods that can detect greater ankle dorsiflexion range of motion (DROM) limitation in the injured limb; (2) determine whether differences in weightbearing measurements exist even in the absence of DROM limitations in the injured limb according to non-weightbearing measurements; and (3) examine associations between DROM in the weightbearing and non-weightbearing positions and compare those between a patient group with foot and ankle injuries and a healthy group. Methods Eighty-two patients with foot and ankle injuries (e.g., fractures, ligament and tendon injuries) and 49 healthy individuals participated in this study. Non-weightbearing DROM was measured under two different conditions: prone position with knee extended and prone position with knee flexed. Weightbearing DROM was measured as the tibia inclination angle (weightbearing angle) and distance between the big toe and wall (weightbearing distance) at maximum dorsiflexion. The effects of side (injured, uninjured) and measurement method on DROM in the patient groups were assessed using two-way repeated-measures ANOVA and t-tests. Pearson correlations between measurements were assessed. In addition, we analyzed whether patients without non-weightbearing DROM limitation (≤ 3 degrees) showed limitations in weightbearing DROM using t-tests with Bonferroni correction. Results DROM in patient groups differed significantly between legs with all measurement methods (all: P < 0.001), with the largest effect size for weightbearing angle (d = 0.95). Patients without non-weightbearing DROM limitation (n = 37) displayed significantly smaller weightbearing angle and weightbearing distance on the injured side than on the uninjured side (P < 0.001 each), with large effect sizes (d = 0.97–1.06). Correlation coefficients between DROM in non-weightbearing and weightbearing positions were very weak (R = 0.17, P = 0.123) to moderate (R = 0.26–0.49, P < 0.05) for the patient group, and moderate to strong for the healthy group (R = 0.51–0.69, P < 0.05). Conclusions DROM limitations due to foot and ankle injuries may be overlooked if measurements are only taken in the non-weightbearing position and should also be measured in the weightbearing position. Furthermore, DROM measurements in non-weightbearing and weightbearing positions may assess different characteristics, particularly in patient group. Level of evidence Level IV, cross-sectional study

External focus instruction using a paper balloon: impact on trunk and lower extremity muscle activity in isometric single-leg stance for healthy males

IntroductionCore stability is crucial for preventing and rehabilitating lumbar spine injuries. An external focus instruction using a paper balloon is an effective way to activate the trunk muscles. However, the degree of trunk and lower extremity muscle activation during single leg stance with external focus instruction using a paper balloon is unknown. This study aimed to investigate the core muscle involving activity in the trunk and lower extremities on both the support and non-support sides with or without using external focus instruction using a paper balloon during isometric single-leg stance.MethodsThirteen healthy males aged 20–28 years volunteered to take part in this study and performed a single leg stance task with and without an external focus instruction, pressing their non-supporting foot onto a paper balloon without crushing it. The participant's muscle electrical activity was recorded during the single leg task using surface EMG and intramuscular EMG for six trunk muscles (transversus abdominis, internal oblique, external oblique, rectus abdominis, multifidus, and lumbar erector spinae) and five lower extremity muscles (gluteus maximus, gluteus medius, adductor longus, rectus femoris, and biceps femoris)ResultsCompared to the normal single leg stance, the external focus instruction task using a paper balloon showed significantly increased transversus abdominis (p &lt; 0.001, p &lt; 0.001), internal oblique (p = 0.001, p &lt; 0.001), external oblique (p = 0.002, p = 0.001), rectus abdominal (p &lt; 0.001, p &lt; 0.001), lumbar multifidus (p = 0.001, p &lt; 0.001), lumbar erector spinae (p &lt; 0.001, p = 0.001), adductor longus (p &lt; 0.001, p &lt; 0.001), rectus femoris (p &lt; 0.001, p &lt; 0.001), and biceps femoris (p &lt; 0.010, p &lt; 0.001) muscle activity on the support and non-support sides.ConclusionIn conclusion, external focus instruction using a paper balloon significantly activates the trunk and lower extremities muscles on both the support and non-support sides. This finding provides insights for designing programs to improve coordination and balance. The benefits extend to diverse individuals, encompassing athletes, tactical professionals, and the general population, mitigating the risk of injury or falls linked to inadequate lower limb balance