Dissociation of Recovery of Muscle Activation and Force Following a Sustained Maximal Isometiric Contraction

To investigate time-dependency of nervous system recovery following muscular contractions, subjects (n=10) performed two bouts (B1, B2) of sustained maximal isometric handgrip contractions separated by 10- min recovery. Force and surface EMG were collected continuously throughout contraction bouts but were analyzed at 15 sec intervals (1 sec segments). iEMG and mean power frequency (MPF) were calculated for the brachioradialis (BR), flexor carpi radialis (FCR) flexor carpi ulnaris (FCU), and flexor digitorum profundus (FDP) muscles. Muscle activation (iEMG-MPF: BR:68-20%; FCR:72-16%; FCU: 65-20%; FDP:48-50%, respectively) and isometric force (88%) decreased following B1(120-sec contraction). Following recovery, initial force of B2 was significantly less than B1 (23%); however muscle activation (iEMG) was similar to B1 for BR, FCR and FDP. Initial B2 FCU iEMG activity was lower but increased to B1 levels by 15 sec; remaining similar throughout. MPF was similar and decreased similarly over time in both bouts but tended to be higher at initiation of B2. The mechanical response was similar in both bouts despite differences in initial force generation (B1: y = -0.172x+22.7; R2=0.98; B2: y = -0.182x+17.9 R2=0.97). Incomplete recovery of force observed in B2 suggests interference in excitation-contraction coupling while fatigue within each bout appears specifically related to changes in muscle activation

Primary peritoneal mesothelioma: A rare cause of malignant ascites

Abstract Introduction: The evaluation of peritoneal masses requires a focused, systematic approach. While peritoneal fluid analysis and axial imaging are essential to the workup, further analysis is often needed for a final diagnosis. We present a case of primary peritoneal mesothelioma mimicking peritoneal carcinomatosis of gastrointestinal origin on computerized tomography (CT) imaging. Case presentation: A 61-year-old man presented to the hospital with an approximate 1-month history of abdominal distention, dyspnea, nausea and fatigue. Peritoneal studies revealed serum-ascites-albumin-gradient (SAAG) of less than 1.1, consistent with non-portal hypertension ascites. CT abdomen revealed large-volume ascites with omental caking, concerning for peritoneal carcinomatosis. Peritoneal fluid cytology was initially inconclusive, prompting ultrasound-guided peritoneal biopsies, which revealed primary abdominal mesothelioma. Conclusions: Neither CT nor peritoneal cytology are typically sufficient for the diagnosis of peritoneal mesothelioma. When strong clinical suspicion exists, early tissue biopsies should be pursued