Potentiation of concentric plantar flexion torque following eccentric and isometric muscle actions

In a stretch-shortening cycle (SSC) the concentric muscle action is enhanced by a preceding eccentric muscle action. The hypothesis of the present study is that a preceding isometric action can also have an effect on a following concentric action, but to a lesser degree. A KINetic-COMmunicator II dynamometer was used to test muscle strength of the plantar flexion of the right foot in 20 healthy women. Maximal voluntary torque measurements were made at different angular velocities (120^o s^-1 and 240^o s^-1) and the range of motion of the ankle joint was 78–125^o. The assessment was based on concentric torque output and EMG recording from the gastrocnemius muscle under three different types of testing conditions (concentric actions with and without preceding eccentric or isometric actions, all with maximal efforts). The results showed that preceding muscle actions led to greater concentric torque output (P < 0.01) between 90 and 99^o plantar flexion. However, the increase in the concentric action was significantly (P < 0.01) larger with eccentric than with isometric preceding action, regardless of velocity. The EMG activity of the concentric action showed unchanged or lower values when preceded by a muscle action. In this model our conclusion is that the main reason for larger concentric torque values after a preceding muscle action is that time is sufficient for maximal muscle tension development; in addition, elastic energy is stored, particularly during the preceding eccentric action. Our results show that the effect of preceding muscle actions should be taken into account when measuring isokinetic muscle strength at relatively small angular movements.     

How to calculate human muscle fibre areas in biopsy samples—methodological considerations

Cross-sectional muscle fibre areas (type I, IIA and IIB) were determined in duplicate biopsies from the left vastus lateralis (n=11) and in biopsies from right and left vastus lateralis (n=8).The SD for the difference in means between duplicate biopsies was 510 μm² for type I, 1020 μm² for type II A and 860 μm² for type II B.Expressed as coefficient of variation (CV) these SD constituted 10, 15 and 15%, respectively. The variation in fibre size within a sample was considerably less than the variation between samples on the assumption that at least 15–20 areas of each fibre type were measured per sample. No difference in mean fibre area for type I, IIA and IIB fibres was obtained between the right and left muscle. Several artefacts due to the sampling and preparing procedures are discussed and a method for determining muscle fibre areas in biopsy samples is suggested.     

Metastatic clear cell renal carcinoma to the auricular region disguised as a vascular thrombus: Case report

In about 25‐30% of patients with primary renal cell carcinoma, metastasis is not uncommon and usually does not give rise to difficulties in diagnosis. However, its presentation as a subcutaneous mass following an elapse of several years after the initial diagnosis is not only uncommon but may be also mistaken for a thrombus in imaging studies due to its common high vascularization. We present here a case of a 70‐year‐old woman with an oncologic history of renal cell carcinoma who noticed after five years a mass in the auricular region radiologically suggestive of a vascular thrombus. Fine‐needle aspiration cytology showed malignant epithelial cells compatible with metastasis of renal clear cell carcinoma, supported by immunohistochemistry performed on the cell block. This rather uncommon presentation and precise diagnosis by fine‐needle aspiration prompted us to report the case, emphasizing the role of cytopathology as a useful, fast and minimally invasive method for clarifying the neoplastic nature of highly vascularized lesions.     

Hydatid cyst of femur,radiologically mimicking a sarcoma

Hydatid disease is a rare pathology, but relatively common in the Mediterranean, the Middle East, Central Asia, and East Africa. It may develop in almost any part of the body, although most hydatid cysts occur in the liver or in the lung. Bone involvement is rare, and accounts for only 0.5% to 4% of all locations. Most of the hydatid cyst are diagnosed on the basis of their clinical and radiological presentation. However, in cases with an atypical presentation, FNAC may be used to evaluate the nature of lesion.     

External validation of a data‐driven algorithm for muscular activity identification during sleep

Several automated methods for scoring periodic limb movements during sleep (PLMS) and rapid eye movement (REM) sleep without atonia (RSWA) have been proposed, but most of them were developed and validated on data recorded in the same clinic, thus they may be biased. This work aims to validate our data‐driven algorithm for muscular activity detection during sleep, originally developed based on data recorded and manually scored at the Danish Center for Sleep Medicine. The validation was carried out on a cohort of 240 participants, including de novo Parkinson's disease (PD) patients and neurologically healthy controls, whose sleep data were recorded and manually evaluated at Paracelsus‐Elena Klinik, Kassel, Germany. In the German cohort, the algorithm showed generally good agreement between manual and automated PLMS indices, and identified with 88.75% accuracy participants with PLMS index above 15 PLMS per hour of sleep, and with 84.17% accuracy patients suffering from REM sleep behaviour disorder (RBD) showing RSWA. By comparing the algorithm performances in the Danish and German cohorts, we hypothesized that inter‐clinical differences may exist in the way limb movements are manually scored and how healthy controls are defined. Finally, the algorithm performed worse in PD patients, probably as a result of increased artefacts caused by abnormal motor events related to neurodegeneration. Our algorithm can identify, with reasonable performance, participants with RBD and increased PLMS index from data recorded in different centres, and its application may reveal inter clinical differences, which can be overcome in the future by applying automated methods.     

基于肌电信号分析研究柔性电极设计参数对电极性能的影响

柔性电极因其穿戴式表面肌电采集的优势而得到研究学者的广泛关注,但很少有研究针对柔性电极的设计参数提 供明确的指导和规范。本实验首先对可能影响电极性能的参数进行了分析;然后利用柔性印刷工艺与喷墨印刷工艺制作 5种不同规格的柔性干电极,并将其与商用湿电极进行对比,设计基于尺侧腕伸肌的肌电采集实验,得到100个表面肌电 信号段;最后对信号段的时频域特性进行分析,从而确定相关参数对电极性能的影响。结果表明增加电极高度后的有源 柔性印刷电路板电极具有更好的信号采集性能。     

A BAFfling liver aspirate: Metastatic high grade SMARCA4 deficient undifferentiated gastroesophageal junction carcinoma masquerading as a hematolymphoid malignancy

Undifferentiated malignant SMARCA4‐deficient neoplasms are rare, recently characterized, high grade, potentially lethal malignancies. Such tumors are characterized by the loss of BRG1 encoded by SMARCA4, a key component of the Switch/Sucrose Non‐Fermenting (SWI/SNF) chromatin remodeling complex. As this complex, also referred as BAF (BRG1/BRM associated factors) complex, is involved in the epigenetic control of hundreds of genes, including those involved in lineage‐specific differentiation, BAF‐deficient tumors, show minimal or no differentiation and are difficult to classify. Their fine needle aspiration (FNA) cytologic features are still poorly defined. Here, we describe a 70‐year‐old man who presented with thickening of the wall of the distal esophagus and stomach and multiple liver and lung lesions. Liver FNA showed relatively uniform dispersed malignant cells with high nucleus: cytoplasm ratio, scant microvacuolated cytoplasm, eccentric nuclei and prominent nucleoli. Mitoses, necrotic debris, nuclear streak artifact, “ghost cells” and focal rhabdoid cytoplasmic inclusions were also present. The liver core biopsy and GI biopsies demonstrated sinusoidal and respectively submucosal involvement by a high grade undifferentiated malignant neoplasm. The tumor cells were negative for all applied markers on immunohistochemistry and flow cytometry, and only showed CD138 and weak PAX5 staining. After an initial diagnosis of hematolymphoid neoplasm, additional stains showed intact INI1 protein and loss of BRG1 protein immunoexpression, establishing the accurate diagnosis. This case highlights the difficulties and potential pitfalls encountered in the FNA diagnosis of BAF‐deficient tumors, the accurate diagnosis of which is important due to their lack of response to conventional therapy and potential response to targeted therapy.