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showing 10 items of 16837 documents
Effects of Mn2+ on the responses induced by different spasmogens in the oestrogen-primed rat uterus
1997
Abstract We investigated the effect of Mn 2+ on the mechanical responses evoked by high K + (60 mM) or low Na + (25 mM) solutions, oxytocin and neurokinin A in the oestrogen-primed rat uterus. In a Ca 2+ -free, Mn 2+ (0.54 mM)-containing solution, high K + or low Na + solutions produced contractions of smaller amplitude than those observed in a normal Ca 2+ (0.54 mM) solution, which were abolished by nifedipine (1 μM). Oxytocin (1 μM) and neurokinin A (1 μM, in the presence of phosphoramidon 1 μM) evoked nifedipine-insensitive contractile responses similar to (oxytocin) or smaller (neurokinin A) in amplitude than those observed in Ca 2+ (0.54 mM)-containing solution. In strips loaded with C…
Effects of inhibitors of cGMP-dependent protein kinase in atrial heart and aortic smooth muscle from rats
1995
Several activators of cGMP-dependent protein kinase (protein kinase G) such as 8-Br-cGMP reduced force of contraction in rat left atria. Inhibitors of protein kinase G antagonized the negative inotropic effect of 8-Br-cGMP but not of acetylcholine in atria. However, the acetylcholine-induced relaxation in aortic rings was significantly inhibited by protein kinase G inhibition. It is concluded that the reduction by 8-Br-cGMP of force of contraction in atria is related to activation of protein kinase G. In response to acetylcholine, activation of protein kinase G is probably a major step in smooth muscle relaxation but is not involved in the reduction of force of contraction in atria.
Neuromuscular fatigue differs following unilateral vs bilateral sustained submaximal contractions
2011
The purpose of the present study was to compare the mechanisms of fatigue induced by a unilateral vs a bilateral submaximal isometric knee extension. Ten physically active men completed two experimental sessions, randomly presented. They were asked to maintain an isometric knee extension force corresponding to 20% of the maximal voluntary contraction (MVC) until task failure with one leg (unilateral) vs two legs (bilateral). MVCs were performed before and after the sustained contraction. Transcutaneous electrical stimuli were used to examine central (voluntary activation) and peripheral (peak doublet force at rest) fatigue on the exercised leg. Time to task failure was significantly shorter…
Changes in motor unit characteristics after eccentric elbow flexor exercise
2010
Morphological evidence suggests that fast-twitch fibers are prone to disruption of their membrane structures by eccentric exercise. However, it is unclear how this is reflected in the discharge rate and action potential propagation of individual motor units, especially at high contraction levels. High-density surface electromyograms were recorded from biceps brachii muscle and decomposed to individual motor unit action potentials at isometric contraction levels between 10% and 75% of maximal voluntary contraction (MVC) before intermittent maximal elbow flexor eccentric exercise, and two hours (2H), two days (2D) and four days (4D) post-exercise. Maximal voluntary force decreased by 21.3±5.6…
Changes in neural drive to calf muscles during steady submaximal contractions after repeated static stretches
2021
Key points: Repeated static-stretching interventions consistently increase the range of motion about a joint and decrease total joint stiffness, but findings on the changes in muscle and connective-tissue properties are mixed. The influence of these stretch-induced changes on muscle function at submaximal forces is unknown. To address this gap in knowledge, the changes in neural drive to the plantar flexor muscles after a static-stretch intervention were estimated. Neural drive to the plantar flexor muscles during a low-force contraction increased after repeated static stretches. These findings suggest that adjustments in motor unit activity are necessary at low forces to accommodate reduct…
Hirayama disease – Early MRI diagnosis of subacute medullary ischemia: A case report
2020
Background: Hirayama disease (HD) is a rare, benign, and self-limiting motor neuron disorder that results in selective motor impairment of the C7-T1 myotomes. It is characterized by progressive, unilateral, or bilateral asymmetric muscle atrophy of the distal upper extremities and myelopathy. Case Description: A 23-year-old male presented with bilateral atrophy of the thenar/hypothenar eminences/ interosseous muscles, plus left-hand weakness. The cervical MRI documented subacute ischemic damage of the distal cervical cord. To rule out a tumor and reduce questionable cord compression, the patient underwent a C5–C6 anterior cervical discectomy and fusion (ACDF) immediately followed by a lami…
Core Muscle Activity, Exercise Preference, and Perceived Exertion during Core Exercise with Elastic Resistance versus Machine
2015
Objectives. To investigate core muscle activity, exercise preferences, and perceived exertion during two selected core exercises performed with elastic resistance versus a conventional training machine.Methods. 17 untrained men aged 26–67 years participated in surface electromyography (EMG) measurements of five core muscles during torso-twists performed from left to right with elastic resistance and in the machine, respectively. The order of the exercises was randomized and each exercise consisted of 3 repetitions performed at a 10 RM load. EMG amplitude was normalized (nEMG) to maximum voluntary isometric contraction (MVC).Results. A higher right erector spinae activity in the elastic exer…
Iris Claw Phakic Lens—Intermediate and Long-term Corneal Endothelial Changes
1994
OBJECTIVE: To study the alterations in the corneal endothelial layer two years after the implantation of iris claw phakic lenses. STUDY DESIGN: Prospective study of postoperative results with a minimum follow-up of 6 months, maximum of two years and a mean of 14 months. SETTING: Department of Ophthalmology, ‘La Fe’ University Hospital, Department of Surgery of Valencia School of Medicine, Valencia, Spain. PATIENTS: Ninety eyes of 70 patients presenting high myopia who underwent anterior chamber phakic lens implantation with iris fixation IOLs in the last two years. MAIN OUTCOME MEASURES: Non-contact specular microscopy with video image system was used to perform examination of the corneal e…
Impact of the COVID-19 pandemic on hospitalizations for acute coronary syndromes: a multinational study
2021
Abstract Background COVID-19 has challenged the health system organization requiring a fast reorganization of diagnostic/therapeutic pathways for patients affected by time-dependent diseases such as acute coronary syndromes (ACS). Aim To describe ACS hospitalizations, management, and complication rate before and after the COVID-19 pandemic was declared. Design Ecological retrospective study. Methods: We analyzed aggregated epidemiological data of all patients > 18 years old admitted for ACS in twenty-nine hub cardiac centers from 17 Countries across 4 continents, from December 1st, 2019 to April 15th, 2020. Data from December 2018 to April 2019 were used as historical period. Results…
Effects of the Combination of Candesartan plus Captopril in Elderly Patients with Anterior Myocardial Infarction
2000
Objective: To verify the feasibility, tolerability and efficacy of the combination of captopril (75 mg/day) and candesartan (8 mg/day) in early postinfarction phases of not thrombolysed and unreperfused anterior acute myocardial infarction (AMI) in elderly patients. Design and Patients: 71 patients (aged >65 years) hospitalised for anterior AMI were randomised in a double-blind manner into two groups: group A included 35 patients who received captopril 75 mg/day within 3 days of admission plus candesartan 4mg, as a first dose, and 8 mg/day successively; group B included 36 patients who received captopril 75 mg/day and placebo. 90 days after admission, patients underwent echocardiography to …