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Heart muscle contraction

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https://www.readbyqxmd.com/read/29026428/evaluation-of-the-physiological-activity-of-venom-from-the-eurasian-water-shrew-neomys-fodiens
#1
Krzysztof Kowalski, Paweł Marciniak, Grzegorz Rosiński, Leszek Rychlik
BACKGROUND: Animal toxins can have medical and therapeutic applications. Principally, toxins produced by insects, arachnids, snakes and frogs have been characterized. Venomous mammals are rare, and their venoms have not been comprehensively investigated. Among shrews, only the venom of Blarina brevicauda has been analysed so far, and blarina toxin has been proven to be its main toxic component. It is assumed that Neomys fodiens employs its venom to hunt larger prey. However, the toxic profile, properties and mode of action of its venom are largely unknown...
2017: Frontiers in Zoology
https://www.readbyqxmd.com/read/29024827/left-ventricular-non-compaction-with-ebstein-anomaly-attributed-to-a-tpm1-mutation
#2
Aleksandra Nijak, Maaike Alaerts, Cuno Kuiperi, Anniek Corveleyn, Bert Suys, Bernard Paelinck, Johan Saenen, Emeline Van Craenenbroeck, Lut Van Laer, Bart Loeys, Aline Verstraeten
Left ventricular non-compaction (cardiomyopathy) (LVN(C)) is a rare hereditary cardiac condition, resulting from abnormal embryonic myocardial development. While it mostly occurs as an isolated condition, association with other cardiovascular manifestations such as Ebstein anomaly (EA) has been reported. This congenital heart defect is characterized by downward displacement of the tricuspid valve and leads to diminished ventricular size and function. In an autosomal dominant LVN(C) family consisting of five affected individuals, of which two also presented with EA and two others with mitral valve insufficiency, we pursued the genetic disease cause using whole exome sequencing (WES)...
October 9, 2017: European Journal of Medical Genetics
https://www.readbyqxmd.com/read/29018624/genome-methylation-and-regulatory-functions-for-hypoxic-adaptation-in-tibetan-chicken-embryos
#3
Yawen Zhang, Wenyu Gou, Jun Ma, Hongliang Zhang, Ying Zhang, Hao Zhang
Tibetan chickens have unique adaptations to the extreme high-altitude environment that they inhabit. Epigenetic DNA methylation affects many biological processes, including hypoxic adaptation; however, the regulatory genes for DNA methylation in hypoxic adaptation remain unknown. In this study, methylated DNA immunoprecipitation with high-throughput sequencing (MeDIP-seq) was used to provide an atlas of the DNA methylomes of the heart tissue of hypoxic highland Tibetan and lowland Chahua chicken embryos. A total of 31...
2017: PeerJ
https://www.readbyqxmd.com/read/29016754/cardiac-troponins-from-myocardial-infarction-to-chronic-disease
#4
Kyung Chan Park, David C Gaze, Paul O Collinson, Michael S Marber
Elucidation of the physiologically distinct subunits of troponin in 1973 greatly facilitated our understanding of cardiac contraction. Although troponins are expressed in both skeletal and cardiac muscle, there are isoforms of troponin I/T expressed selectively in the heart. By exploiting cardiac-restricted epitopes within these proteins, one of the most successful diagnostic tests to-date has been developed: cardiac troponin (cTn) assays. For the past decade, cTn has been regarded as the gold-standard marker for acute myocardial necrosis: the pathological hallmark of acute myocardial infarction (AMI)...
September 14, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28973166/activated-braf-induces-esophageal-dilation-and-gastric-epithelial-hyperplasia-in-mice
#5
Shin-Ichi Inoue, Shingo Takahara, Takeo Yoshikawa, Tetsuya Niihori, Kazuhiko Yanai, Yoichi Matsubara, Yoko Aoki
Germline mutations in BRAF are a major cause of cardio-facio-cutaneous (CFC) syndrome, which is characterized by heart defects, characteristic craniofacial dysmorphology and dermatologic abnormalities. Patients with CFC syndrome also commonly show gastrointestinal dysfunction, including feeding and swallowing difficulties and gastroesophageal reflux. We have previously found that knock-in mice expressing a Braf Q241R mutation exhibit CFC syndrome-related phenotypes, such as growth retardation, craniofacial dysmorphisms, congenital heart defects and learning deficits...
September 14, 2017: Human Molecular Genetics
https://www.readbyqxmd.com/read/28970803/high-frequency-stimulation-of-the-pelvic-nerve-inhibits-urinary-voiding-in-anesthetized-rats
#6
Jonathan J Crook, Thelma A Lovick
Urge Urinary Incontinence: "a sudden and uncontrollable desire to void which is impossible to defer" is extremely common and considered the most bothersome of lower urinary tract conditions. Current treatments rely on pharmacological, neuromodulatory, and neurotoxicological approaches to manage the disorder, by reducing the excitability of the bladder muscle. However, some patients remain refractory to treatment. An alternative approach would be to temporarily suppress activity of the micturition control circuitry at the time of need i...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28970201/evidence-of-a-greater-functional-sympatholysis-in-habitually-aerobic-trained-postmenopausal-women
#7
Nicholas T Kruse, William E Hughes, Satoshi Hanada, Kenichi Ueda, Joshua M Bock, Erika Iwamoto, Darren P Casey
Habitual aerobic exercise attenuates elevated vasoconstriction during acute exercise (functional sympatholysis) in older men; however, this effect remains unknown in postmenopausal women (PMW). This study tested the hypothesis that, PMW who participate in habitual aerobic exercise, demonstrate a greater functional sympatholysis compared to their untrained counterparts. Nineteen PMW (untrained, n=9 vs. trained, n=10) performed 5-minutes of steady-state (SS) forearm exercise at relative (10% and 20% of maximum; MVC) and absolute (5 kg) contraction intensities...
September 28, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28964151/complex-blood-flow-patterns-in-an-idealized-left-ventricle-a-numerical-study
#8
Anna Tagliabue, Luca Dedè, Alfio Quarteroni
In this paper, we study the blood flow dynamics in a three-dimensional (3D) idealized left ventricle of the human heart whose deformation is driven by muscle contraction and relaxation in coordination with the action of the mitral and aortic valves. We propose a simplified but realistic mathematical treatment of the valves function based on mixed time-varying boundary conditions (BCs) for the Navier-Stokes equations modeling the flow. These switchings in time BCs, from natural to essential and vice versa, model either the open or the closed configurations of the valves...
September 2017: Chaos
https://www.readbyqxmd.com/read/28963742/transfusion-acquired-hepatitis-e-infection-misdiagnosed-as-severe-critical-illness-polyneuromyopathy-in-a-heart-transplant-patient
#9
Julie Belliere, Florence Abravanel, Marie Béatrice Nogier, Salima Martinez, Pascal Cintas, Sébastien Lhomme, Laurence Lavayssière, Olivier Cointault, Stanislas Faguer, Jacques Izopet, Nassim Kamar
This is the case of a 56-year-old man who underwent heart transplantation. Within the first postoperative days, his respiratory and limb muscles weakened, which was attributed to critical illness polyneuromyopathy (CIPM). At day 70 post transplantation, he had increased liver enzyme levels and acute hepatitis E virus (HEV) infection was diagnosed. HEV RNA was found in the serum, stools, and cerebrospinal fluid. Results of further investigations suggested a possible HEV-related polyradiculoneuropathy. At transplantation, the patient was negative for immunoglobulin (Ig)G, IgM, and HEV RNA...
September 29, 2017: Transplant Infectious Disease: An Official Journal of the Transplantation Society
https://www.readbyqxmd.com/read/28959214/adrenergic-stress-protection-of-human-ips-cell-derived-cardiomyocytes-by-fast-kv7-1-recycling
#10
Ilaria Piccini, Edda Fehrmann, Stefan Frank, Frank U Müller, Boris Greber, Guiscard Seebohm
The fight-or-flight response (FFR), a physiological acute stress reaction, involves positive chronotropic and inotropic effects on heart muscle cells mediated through β-adrenoceptor activation. Increased systolic calcium is required to enable stronger heart contractions whereas elevated potassium currents are to limit the duration of the action potentials and prevent arrhythmia. The latter effect is accomplished by an increased functional activity of the Kv7.1 channel encoded by KCNQ1. Current knowledge, however, does not sufficiently explain the full extent of rapid Kv7...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28953985/relationship-between-aerobic-capacity-and-pelvic-floor-muscles-function-a-cross-sectional-study
#11
S P Jürgensen, A Borghi-Silva, A M F G Bastos, G N Correia, V S Pereira-Baldon, R Cabiddu, A M Catai, P Driusso
The objective of this study was to evaluate the relationship between aerobic capacity and pelvic floor muscles (PFM) function in adult women. Women aged 18 or over and without urinary dysfunction or other chronic diseases were eligible to participate. They completed the habitual physical activity (HPA) questionnaire, underwent a PFM functional evaluation by palpation and perineometry, and performed a submaximal (between 75 and 85% of maximum heart rate) cardiopulmonary exercise (CPX) test to determine the ventilatory anaerobic threshold (VAT)...
September 21, 2017: Brazilian Journal of Medical and Biological Research, Revista Brasileira de Pesquisas Médicas e Biológicas
https://www.readbyqxmd.com/read/28951939/biological-and-pro-angiogenic-properties-of-genetically-modified-human-primary-myoblasts-overexpressing-placental-growth-factor-in-in-vitro-and-in-vivo-studies
#12
Agnieszka Zimna, Bartosz Wiernicki, Tomasz Kolanowski, Natalia Rozwadowska, Agnieszka Malcher, Wojciech Labedz, Tomasz Trzeciak, Katarzyna Chojnacka, Katarzyna Bednarek-Rajewska, Przemyslaw Majewski, Maciej Kurpisz
Cardiovascular diseases are a growing problem in developing countries; therefore, there is an ongoing intensive search for new approaches to treat these disorders. Currently, cellular therapies are focused on healing the damaged heart by implanting stem cells modified with pro-angiogenic factors. This approach ensures that the introduced cells are capable of fulfilling the complex requirements of the environment, including the replacement of the post-infarction scar with cells that are able to contract and promote the formation of new blood vessels that can supply the ischaemic region with nutrients and oxygen...
September 26, 2017: Archivum Immunologiae et Therapiae Experimentalis
https://www.readbyqxmd.com/read/28931622/connexins-in-cardiovascular-and-neurovascular-health-and-disease-pharmacological-implications
#13
REVIEW
Luc Leybaert, Paul D Lampe, Stefan Dhein, Brenda R Kwak, Peter Ferdinandy, Eric C Beyer, Dale W Laird, Christian C Naus, Colin R Green, Rainer Schulz
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication...
October 2017: Pharmacological Reviews
https://www.readbyqxmd.com/read/28915834/skeletal-muscle-mechanics-questions-problems-and-possible-solutions
#14
REVIEW
Walter Herzog
Skeletal muscle mechanics have been studied ever since people have shown an interest in human movement. However, our understanding of muscle contraction and muscle mechanical properties has changed fundamentally with the discovery of the sliding filament theory in 1954 and associated cross-bridge theory in 1957. Nevertheless, experimental evidence suggests that our knowledge of the mechanisms of contraction is far from complete, and muscle properties and muscle function in human movement remain largely unknown...
September 16, 2017: Journal of Neuroengineering and Rehabilitation
https://www.readbyqxmd.com/read/28912726/cardiovascular-and-muscular-consequences-of-work-matched-interval-type-of-concentric-and-eccentric-pedaling-exercise-on-a-soft-robot
#15
Martin Flück, Rebekka Bosshard, Max Lungarella
Eccentric types of endurance exercise are an acknowledged alternative to conventional concentric types of exercise rehabilitation for the cardiac patient, because they reduce cardiorespiratory strain due to a lower metabolic cost of producing an equivalent mechanical output. The former contention has not been tested in a power- and work-matched situation of interval-type exercise under identical conditions because concentric and eccentric types of exercise pose specific demands on the exercise machinery, which are not fulfilled in current practice...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28900912/the-stim-orai-pathway-light-operated-ca-2-entry-through-engineered-crac-channels
#16
Guolin Ma, Shufan Wen, Yun Huang, Yubin Zhou
Ca(2+) signals regulate a plethora of cellular functions that include muscle contraction, heart beating, hormone secretion, lymphocyte activation, gene expression, and metabolism. To study the impact of Ca(2+) signals on biological processes, pharmacological tools and caged compounds have been commonly applied to induce fluctuations of intracellular Ca(2+) concentrations. These conventional approaches, nonetheless, lack rapid reversibility and high spatiotemporal resolution. To overcome these disadvantages, we and others have devised a series of photoactivatable genetically encoded Ca(2+) actuators (GECAs) by installing light sensitivities into a bona fide highly selective Ca(2+) channel, the Ca(2+) release-activated Ca(2+) (CRAC) channel...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28895052/the-effects-of-periostin-in-a-rat-model-of-isoproterenol-mediated-cardiotoxicity
#17
Mahmut Sözmen, Alparslan K Devrim, Yonca B Kabak, Tuba Devrim, Mert Sudagidan
Periostin is an extracellular matrix protein from fasciclin family, and it plays an important role in the cell adhesion, migration, and growth of the organism. Periostin prevents apoptosis while stimulating cardiomyocytes. The present study was designed to investigate cardioprotective effects of the recombinant murine periostin peptide administration in a rat model of isoproterenol (ISO)-induced myocardial injury. The experiment was performed on 84 adult male Sprague Dawley rats in 4 groups (n = 21): control group (1), periostin-treated group (2), ISO-treated group (3), and ISO + periostin-treated group (4)...
September 11, 2017: Cardiovascular Toxicology
https://www.readbyqxmd.com/read/28881022/getting-help-from-frank-and-starling-and-coats-and-bowditch-to-augment-blood-flow-in-heat-stressed-older-adults
#18
Nisha Charkoudian
No abstract text is available yet for this article.
October 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28873335/blood-pressure-response-during-normocapnic-hyperpnoea-is-blunted-in-young-women-compared-to-men
#19
Kaori Shimizu, Kanako Goto, Koji Ishida, Mitsuru Saito, Hiroshi Akima, Keisho Katayama
We hypothesized that young women have a lower arterial blood pressure (BP) response to high inspiratory and expiratory muscle contractions with normocapnic hyperpnoea compared to age-matched men. To test this hypothesis, the cardiovascular response during voluntary normocapnic incremental hyperpnoea was evaluated in young women and compared to that of young men. An incremental respiratory endurance test (IRET) was performed as follows: target minute ventilation was initially set to 30% of the maximal voluntary ventilation (MVV12) and was increased by 10% MVV12 every 3min...
September 2, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28864378/potential-cardiovascular-and-renal-protective-effects-of-vitamin-d-and-coenzyme-q10-in-l-name-induced-hypertensive-rats
#20
Hanan A Shamardl, Sahar M El-Ashmony, Hala F Kamel, Sameer H Fatani
BACKGROUND: Hypertension is one of the primary modifiable risk factors for cardiovascular disease. Adequate vitamin D (vit D) levels have been shown to reduce vascular smooth muscle contraction and to increase arterial compliance, which may be beneficial in hypertension. Further, coenzyme Q10 (COQ10) through its action to lower oxidative stress has been reported to have beneficial effects on hypertension and heart failure. This study examined the possible cardiac and renal protective effects of vit D and COQ10 both separately and in combination with an angiotensin II receptor blocker, valsartan (vals) in l-NAME hypertensive rats...
August 2017: American Journal of the Medical Sciences
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