Median frequency of the myoelectric signal

Summary A study was performed to investigate the changes that occur in the median frequency of the myoelectric signal during local ischemia or reduction of intramuscular temperature produced by surface cooling. Data was obtained from experiments which involved the first dorsal interosseous muscle of 10 female and 16 male subjects. These subjects were asked to perform isometric constant-force abduction contractions of the index finger at 20% and 80% of maximal voluntary contraction level. The initial median frequency (IMF) of the myoelectric signal during the first 0.5 s of contraction was calculated. Results showed a significant reduction of the IMF in contractions performed under ischemic conditions; upon release, the IMF recovered quickly. At 80% maximal voluntary level of contraction, a greater decrease of the IMF was recorded. Similar results were demonstrated during reduction of intramuscular temperature with gradual recovery of the IMF after cooling. These results demonstrate that the median frequency of the myoelectric signal displays behavior similar to that reported for conduction velocity and this is consistent with the notion that accumulation of metabolic byproducts in muscle tissue causes a decrease in the conduction velocity of the muscle fibers.Dr. R. Merletti was on a leave of absence from the Institute of Electrical Engineering, Politecnico di Torino, Italy     

Growth of diploid cells from breast cancers

Cell cultures were derived from normal and cancerous breast tissues and from metastases by methods that selected for relatively adherent epithelial aggregates. Karyotypic analyses of first or second passage cultures yielded predominantly normal diploid cells. Nonclonal aberrations were more common in tumor-derived than in normal cultures. Three of the cultures that originated from metastases were characterized by abnormal clones. These results support observations based on DNA content, which indicate that a considerable fraction of breast cancers are composed predominantly of diploid cells. They differ greatly from chromosomal findings in long-term cultures of tumor effusions and thus emphasize the karyotypic diversity that can be found in tumors from a single tissue of origin--the breast.     

Effect of prostaglandin D2 and I2 on the airways of rhesus monkeys

Prostaglandin (PG) D2 and PGI2 were evaluated to determine their effect on pulmonary function parameters when aerosolized in anesthetized rhesus monkeys. PGD2 resulted in an increase in frequency (f) and pulmonary resistance (rl) and a decrease in peak expiratory flow rate (PEFR), tidal volume (VT), and dynamic compliance (Cdyn), with the major effect on RL. PGI2 primarily effected an increase in f and a decrease in PEFR and VT. PGI2 had a variable effect, generally a decrease, on RL. The metabolite of PGI2, 6-keto-PGF 1 alpha, had no effect on the rhesus airway. PGF 2 alpha responses were similar to PGD2 except that the PGF 2 alpha produced a less strikingly consistent increase in RL. When PGI2 and PGD2 were aerosolized simultaneously, they simulated previously described antigen responses. Further, PGI2 plus PGD2 produced an airway response at 1/10 the concentration of either agent alone.     

Further insight into the task-dependent excitability of motor evoked potentials in first dorsal interosseous muscle in humans

We have reexamined the contradictory evidence in which task-dependent excitation of motor evoked potentials (MEPs) in the first dorsal interosseous (FDI) muscle was stronger with increasingly more complex finger tasks than with individual finger movement tasks. In the first step of the experiment, based on previous findings, we investigated remarkable functional differences between intrinsic and extrinsic hand muscles during complex finger tasks (precision and power grip). During the performance of the tasks, the optimal stimulus intensity of the transcranial magnetic stimulation (TMS) was applied to the contralateral motor cortex. MEPs of the FDI, extensor carpi radialis (ECR), and flexor carpi radialis (FCR) muscles were recorded simultaneously with increased background EMG activity step by step in both tasks. The intensity threshold of TMS was lower in the precision grip. Furthermore, the MEP amplitudes of FDI muscle dependent on the background EMG activity were different between these two tasks, i.e., MEP amplitudes and regression coefficients in a precision grip were larger than those in a power grip. Although our results for MEP amplitude and threshold in the FDI muscle were similar to previous reported evidence, the different contributions of a synergistic muscle (in particular, the ECR muscle) during performance in these tasks was new evidence. Since there were no differences in cutaneous afferent effects on both tasks, corticomotoneuronal (CM) cells connected to FDI motoneurons seemed generally to be more active during precision than power gripping, and there were different contributions from synergistic muscles during the performance of these tasks. In the second part of the experiment, the results obtained from the complex tasks were compared with those from a simple task (isolated index finger flexion). MEP amplitudes, dependent on the background EMG activity during isolated index finger flexion, varied among subjects, i.e., the relationship between the MEP amplitude and the background EMG of the FDI muscle showed individual, strategy-dependent modulation. There were several kinds of individual motor strategies for performing the isolated finger movement. The present results may explain the previous contradictory evidence related to the contribution of the CM system during coordinated finger movement.     

The experiences of peer-facilitators delivering a physical activity intervention for emergency service workers and their families

IntroductionEmergency service workers (e.g. police, fire, ambulance officers) are regularly exposed to occupational stressors and potentially traumatic events, resulting in an increased risk of poor mental and physical health. For example, emergency service workers are twice as likely to experience suicidal thoughts compared to the general population and one in ten will develop posttraumatic stress disorder. Despite this, emergency service workers face barriers to accessing traditional mental healthcare. Physical activity is non-stigmatising and may help improve the mental and physical health of this population; however, novel ways to help people engage are needed. Peers with lived experience may be well-placed to co-deliver physical activity programs alongside health professionals. The aim of this study was to understand the experiences of peer-facilitators co-delivering an online physical activity intervention for emergency service workers and their families.MethodsQualitative interviews were conducted with 6 peer-facilitators. Interviews were audio recorded, transcribed, and analysed using exploratory thematic analysis.ResultsTwo main themes were explored. The first theme related to the value of lived experience that reflected two subthemes, i) credibility and relatedness by virtue of experience; and ii) knowledge and confidence by virtue of experience. The second theme related to the impact of the peer-facilitator role on the peers themselves, whereby peer-facilitators reported an increased sense of purpose and social connection.DiscussionThis qualitative study provides insights into how peer-facilitators can complement health professionals in the delivery of physical activity interventions for emergency service workers. Further research is needed to elucidate training requirements and safety protocols.     

基于胸痛中心急救流程在急性心肌梗死患者救治中的应用

目的探讨基于胸痛中心急救流程在急性心肌梗死(AMI)患者救治中的应用效果。 方法选取镇江市急救中心2017年8月至2021年8月接诊的94例AMI患者为研究对象,其中男性50例,女性44例;年龄42~81岁,平均(60.37±4.31)岁。根据就诊顺序分为对照组和研究组,每组各47例,对照组患者接受常规急救流程,研究组患者接受基于胸痛中心基础上的急救流程,比较两组患者急救各环节时间、不良心血管事件发生率及患者满意度。 结果研究组患者急救各环节时间较对照组更短,两组比较差异有统计学意义(P<0.05);研究组患者不良心血管事件发生率显著低于对照组(6.38%比23.40%),两组比较差异有统计学意义(P<0.05);研究组患者满意度显著高于对照组(93.62%比78.72%),两组比较差异有统计学意义(P<0.05)。 结论基于胸痛中心急救流程可有效缩短急救过程中各环节时间,最大限度降低不良心血管事件发生风险,患者满意度高,对提高AMI患者救治效果、改善预后具有积极意义。     

The clinical utility of a decision-aid to facilitate the use of the hand in real-life activities of patients with distal radius fractures: A case study

BackgroundOccupation-based intervention (OBI) in hand therapy has shown superior benefits in patient-reported performance and physical measures; however, only a few studies have used OBI. We developed a decision-aid to promote the use of an injured hand in the real world (Aid for Decision-making in Occupation Choice for hand; ADOC-H)PurposeTo investigate the clinical utility of the ADOC-H (paper version) in patients with distal radius fractures.Study DesignA prospective case series and a clinical survey for occupational therapists.MethodsThis study comprised a prospective patient case series of 8 patients with distal radius fractures, treated using Volar locking plates, and a clinical survey of 4 experienced occupational therapists.ResultsNo patient or therapist complaints or drop-outs were reported. Active range of motion (wrist), Grip strength, and Disabilities of the Arm, Shoulder, and Hand scores improved for all patients. The ADOC-H induced 158 activities using the injured hand, with activities of daily living (69.8%) selected earlier in the treatment period, and instrumental activities of daily living (63.3%) selected later. The feedback and case studies suggested that the ADOC-H was useful for patients who were afraid of using the hand and, interestingly, patients who were able to use their hand without pain or other problems. The clinical survey showed that most therapists found the ADOC-H effective in facilitating real-life use of an injured hand.ConclusionsThe ADOC-H paper version is an useful tool that can be applied to facilitate patients with distal radius fractures to use their injured hands in real-life settings.     

The Effect of Providing Audiovisual Surgical Information on Decisional Conflict in Patients Undergoing Plate Fixation for Distal Radius Fractures

BackgroudPatients experiencing acute trauma have limited time for their involvement in shared decision making, which may lead to decisional conflict. The purpose of this study was to evaluate whether providing audiovisual surgical information can reduce decisional conflict when deciding between surgical and nonsurgical treatment in patients with distal radius fractures (DRFs) and to evaluate factors that may affect decisional conflict.MethodsWe prospectively enrolled 50 consecutive patients who presented with acute DRFs and chose to undergo surgery, for which volar plate fixation was recommended. We randomized these patients into 2 groups. The test group was given a video clip of audiovisual surgical information in addition to regular information while the control group was only given regular information. The video clip consisted of the purpose, procedure, and effect of the surgery, precautions and complications after the operation, and other treatment options that could be performed if operation was not performed. At 2 weeks after the surgery, we evaluated patients'' decisional conflict using a decisional conflict scale (DCS). In addition, we evaluated factors that might affect decisional conflict, such as age, dominant hand, comorbidities, history of previous operations, perceived disability, and provision of the video clip.ResultsThe test group showed significantly lower DCS scores than the control group (19.6 vs. 32.1, p = 0.001). In multivariate analysis, younger age and provision of the video clip were associated with lower DCS scores.ConclusionsThis study has demonstrated that providing information through audiovisual media such as video clips could reduce decisional conflict in patients who chose to undergo plate fixation for DRFs. This study also suggests that older patients may need more careful doctor-patient communication as they have more decisional conflict than younger patients.     

Arthrodesis of the first metatarsophalangeal joint: The “when and how”

Arthrodesis of the first metatarsophalangeal (MTP) joint has been established as the “gold standard” for the treatment of several first ray disorders, due to its perceived efficacy and the consistently reported good results in the literature. Arthrodesis is a commonly performed procedure for the treatment of end stage arthritis, rheumatoid arthritis with severe deformity, selected cases of severe hallux valgus (with or without signs of degenerative joint disease), as well as a salvage procedure after failed previous operation of the first ray. The goals of a successful 1^st MTP arthrodesis are pain alleviation and deformity correction in order to restore a comfortable gait pattern and to improve shoe wear. Several techniques have been reported with several proposals regarding the preparation of the articular surfaces and the method of definitive fixation. As with any given surgical procedure, various complications may occur after arthrodesis of the 1^st MTP joint, namely delayed union, nonunion, malunion, irritating hardware, etc.