Contract-relax

Actin linked regulatory mechanisms are known to contribute contraction/relaxation in smooth muscle. In order to clarify whether modulation of polymerization/depolymerization of actin filaments affects relaxation process, we examined the effects of cytochalasin D on relaxation process by Ca2+ removal after Ca2+ -induced contraction of β-escin skinned (cell membrane permeabilized) taenia cecum and carotid artery preparations from guinea pigs. Cytochalasin D, an inhibitor of actin polymerization, significantly suppressed the force during relaxation both in skinned taenia cecum and carotid artery...

Vertebral fracture (VF) is one of the most common injuries seen in individuals with osteoporosis, especially in post-menopausal females. There is an increase in bone resorption rate, leading to the destruction of the microarchitecture of bone. A 67-year-old female patient diagnosed with wedge compression fracture of the D12 vertebra, mild compression of the spinal cord, and bilateral foot drop came to a tertiary care hospital, where she underwent spinal fusion at the D11-L1 level and posterior decompression, after which she was referred to physiotherapy, where a patient-tailored treatment protocol was made and implemented over three weeks...

AIM: This study aimed to compare the acute effects of different methods on ankle joint range of motion (ROM) in older adults. MATERIALS AND METHODS: Seventy-eight older adults were randomly divided into three groups. After the warming-up, static stretching, proprioceptive neuromuscular facilitation (PNF) contract-relax, and roller massage were applied, at the same period. Before application, immediately after, 10 and 20 min after application, ankle joint dorsiflexion ROM was measured in the weight-bearing position...

Background The renin-angiotensin system and its metabolites are crucial in the pathogenesis and progression of complications of diabetes. Aim In this study, we aimed to evaluate the effect of angiotensin 1-7 non-peptide agonist AVE 0991 (576 ug/kg/day i.p.) on diabetic endothelial dysfunction. Materials and methods In this experimental animal study, we investigated the effects of angiotensin 1-7 non-peptide agonist AVE 0991 (576 ug/kg/day i.p.) treatment in male Wistar rats. Diabetes was created via injecting streptozotocin (55 mg/kg/i...

Skeletal muscle generates heat via contraction-dependent (shivering) and independent (nonshivering) mechanisms. While this thermogenic capacity of skeletal muscle undoubtedly contributes to the body temperature homeostasis of animals and impacts various cellular functions, the intracellular temperature and its dynamics in skeletal muscle in vivo remain elusive. We aimed to determine the intracellular temperature and its changes within skeletal muscle in vivo during contraction and following relaxation. In addition, we tested the hypothesis that sarcoplasmic reticulum Ca2+ ATPase (SERCA) generates heat and increases the myocyte temperature during a transitory Ca2+ -induced contraction-relaxation cycle...

PURPOSE: To determined sex differences in absolute- and %-reductions in blood flow during intermittent muscular contractions as well as relationships between blood flow reductions and time to task failure (TTF). METHODS: Thirteen males (25 ± 4 years) and 13 females (22 ± 5 years) completed intermittent isometric trapezoidal forearm flexion at 50% maximal voluntary contraction until task failure. Doppler ultrasound was used to measure brachial artery blood flow (BABF) during the 12-s plateau phase and 12-s relaxation phase...

Orgasm is a phase of the human sexual response, and the possible discrepancies between male and female ways to experience it are still not clear in the literature. There is a lack of tools to adequately assess orgasm perception. This study aims to develop an instrument and verify possible differences between males and females. We constructed the Orgasmic Perception Questionnaire (OPQ) through different stages: first, 316 items selection was conducted on a sample of 96 people, where items came mainly from written descriptions of orgasm perception; second, an exploratory factor analysis was conducted on 674 Italian adults with a 63-item OPQ; finally, a confirmatory factor analysis was conducted on 1100 Italian adults with a 47-item OPQ...

Hypertrophic cardiomyopathy (HCM) is frequently caused by mutations in the cardiac myosin binding protein-C (cMyBP-C) encoding gene MYBPC3. In the Netherlands, approximately 25% of patients carry the MYBPC3c.2373InsG founder mutation. Most patients are heterozygous (MYBPC3+/InsG ) and have highly variable phenotypic expression, whereas homozygous (MYBPC3InsG/InsG ) patients have severe HCM at a young age. To improve understanding of disease progression and genotype-phenotype relationship based on the hallmarks of human HCM, we characterized mice with CRISPR/Cas9-induced heterozygous and homozygous mutations...

Several reports have demonstrated that depressive disorder is related to somatic symptoms including gastrointestinal or genitourinary alterations. The pathophysiological mechanisms underlying the gastrointestinal or genitourinary alterations associated with the depression are still not fully understood. Therefore, this study aimed to evaluate the motor activity of gastrointestinal (fundus of stomach and duodenum) and genitourinary tract (bladder) in a stress-based animal model of depression. Adult male mice were submitted to uncontrollable and unpredictable stress (learned helplessness model), controllable stress and non-stressful situations (control)...

PURPOSE: When exercising above the lactic threshold (LT), the slow component of oxygen uptake ([Formula: see text]) appears, mainly ascribed to the progressive recruitment of Type II fibers. However, also the progressive decay of the economy of contraction may contribute to it. We investigated oxygen uptake ([Formula: see text]) during isometric contractions clamping torque (T) or muscular activation to quantify the contributions of the two mechanisms. METHODS: We assessed for 7 min T of the leg extensors, net oxygen uptake ([Formula: see text]) and root mean square (RMS) from vastus lateralis (VL) in 11 volunteers (21 ± 2 yy; 1...

Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSC-CMs) hold tremendous potential for cardiovascular disease modeling, drug screening, personalized medicine, and pathophysiology studies. The availability of a robust protocol and functional assay for studying phenotypic behavior of hiPSC-CMs is essential for establishing an in vitro disease model. Many heart diseases manifest due to changes in the mechanical strain of cardiac tissue. Therefore, non-invasive evaluation of the contractility properties of hiPSC-CMs remains crucial to gain an insight into the pathogenesis of cardiac diseases...

Evidence exists that heart failure (HF) has an overall impact of 1-2% in the global population being often associated with comorbidities that contribute to increased disease prevalence, hospitalization, and mortality. Recent advances in pharmacological approaches have significantly improved clinical outcomes for patients with vascular injury and HF. Nevertheless, there remains an unmet need to clarify the crucial role of nitric oxide/cyclic guanosine 3',5'-monophosphate (NO/cGMP) signalling in cardiac contraction and relaxation, to better identify the key mechanisms involved in the pathophysiology of myocardial dysfunction both with reduced (HFrEF) as well as preserved ejection fraction (HFpEF)...

Cardiac muscle contraction is distinct from the contraction of other muscle types. The heart continuously undergoes contraction-relaxation cycles throughout an animal's lifespan. It must respond to constantly varying physical and energetic burdens over the short term on a beat-to-beat basis and relies on different mechanisms over the long term. Muscle contractility is based on actin and myosin interactions that are regulated by cytoplasmic calcium ions. Genetic variants of sarcomeric proteins can lead to the pathophysiological development of cardiac dysfunction...

BACKGROUND: The corpus cavernosum (CC) containing sinusoids plays fundamental roles for erection. Analysis of pathological changes in the erectile system is studied by recent experimental systems. Various in vitro models utilizing genital mesenchymal-derived cells and explant culture systems are summarized. METHODS: 3D reconstruction of section images of murine CC was created. Ectopic chondrogenesis in aged mouse CC was shown by a gene expression study revealing the prominent expression of Sox9...

The optimal motion management strategy for patients receiving stereotactic arrhythmia radioablation (STAR) for the treatment of ventricular tachycardia (VT) is not fully known. We developed a framework using a digital phantom to simulate cardiorespiratory motion in combination with different motion management strategies to gain insight into the impact of cardiorespiratory motion on STAR. The 4D XCAT phantom was expanded with the 17-segment left ventricular (LV) model which allowed placement of STAR targets in standardized ventricular regions...

Biological fish can always sense the state of water flow and regulate the angle of attack in time, so as to maintain the highest movement efficiency during periodic flapping. The biological adjustment of the caudal fin's angle of attack (AoA) depends on the contraction/relaxation of the tail muscles, accompanying the variation in tail stiffness. During an interaction with external fluid, it helps to maintain the optimal angle of attack during movement, to improve the propulsion performance. Inspired by this, this paper proposes a tail joint motion control scheme based on AoA feedback for the high-speed swimming of bionic dolphins...

Large tumor suppressor kinase 2 ( Lats2 ) is a member of the Hippo pathway, a critical regulator of organ size. Since Lats2 activity may trigger mitochondrial dysfunction, a key pathogenic factor in acute myocardial infarction (AMI), this study sought to investigate whether Lats2 deletion confers cardioprotection in AMI. AMI was induced in cardiomyocyte-specific Lats2 knockout ( Lats2Cko ) and control ( Lats2flox ) mice. Twenty-eight days after AMI surgery, myocardial performance and mitochondrial homeostasis were impaired in Lats2flox mice...

AIMS: Upregulation of Ca2+ /calmodulin-dependent protein kinase II (CaMKII) contributes to the pathogenesis of cardiovascular disease, including hypertension. Transgenic rats expressing the human angiotensinogen gene [TGR (hAGT)L1623] are a new novel humanized model of hypertension that associates with declines in cardiac contractile function and β-adrenergic receptor (AR) reserve. The molecular mechanisms are unclear. We tested the hypothesis that in TGR (hAGT)L1623 rats, left ventricular (LV) myocyte CaMKIIδ and β3 -AR are upregulated, but β1 -AR is down-regulated, which are important causes of cardiac dysfunction and β-AR desensitization...

Uterine artery hydrogen sulfide (H2S) production is augmented in pregnancy and upon stimulation by systemic/local vasodilators, contributing to pregnancy-dependent uterine vasodilation; however, how H2S exploits this role is largely unknown. S-sulfhydration converts free thiols (-SH) to persulfides (-SSH) at reactive cysteine(s) on targeted proteins to affect the entire proteome post-translationally, representing the main route for H2S to elicit its function. Herein we used Tag-Switch to quantify changes in sulfhydrated (SSH-) proteins (i...

OBJECTIVE: This study aimed to evaluate the diagnostic accuracy of the intelligent flipper (IFLIP) system in identifying binocular vision anomalies. PATIENTS AND METHODS: This study comprised 70 participants aged 18 to 22. Participants underwent comprehensive eye assessments, including measurement of visual acuity, refraction, far and near cover test, stereopsis, and worth four dot test. The manual accommodation amplitude and facility, as well as the IFLIP system test, were also evaluated...