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Source: Frontiers in Physiology

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Total 282 results found since Jan 2013.

Hydrogen Sulfide Ameliorates Homocysteine-Induced Cardiac Remodeling and Dysfunction
Patients with diabetes, a methionine-rich meat diet, or certain genetic polymorphisms show elevated levels of homocysteine (Hcy), which is strongly associated with the development of cardiovascular disease including diabetic cardiomyopathy. However, reducing Hcy with folate shows no beneficial cardiac effects. We have previously shown that hydrogen sulfide (H₂S), a byproduct of Hcy through transsulfuration by cystathionine beta synthase (CBS), donor mitigates Hcy-induced hypertrophy in cardiomyocytes. However, the in vivo cardiac effects of H₂S in the context of hyperhomocysteinemia (HHcy) have not been studied. We tes...
Source: Frontiers in Physiology - May 23, 2019 Category: Physiology Source Type: research

The Relationship Between Blood Flow and Motor Unit Firing Rates in Response to Fatiguing Exercise Post-stroke
We quantified the relationship between the change in post-contraction blood flow with motor unit firing rates and metrics of fatigue during intermittent, sub-maximal fatiguing contractions of the knee extensor muscles after stroke. Ten chronic stroke survivors (>1-year post stroke) and nine controls participated. Throughout fatiguing contractions, the discharge timings of individual motor units were identified by decomposition of high-density surface EMG signals. After five consecutive contractions, a blood flow measurement through the femoral artery was obtained using an ultrasound machine and probe designed for vascular ...
Source: Frontiers in Physiology - May 9, 2019 Category: Physiology Source Type: research

The Potential of Stem Cell Therapy to Repair White Matter Injury in Preterm Infants: Lessons Learned From Experimental Models
Diffuse white matter injury (dWMI) is a major cause of morbidity in the extremely preterm born infant leading to life-long neurological impairments, including deficits in cognitive, motor, sensory, psychological and behavioral functioning. At present, no treatment options are clinically available to combat dWMI and therefore exploring novel strategies is urgently needed. In recent years, the pathophysiology underlying dWMI has slowly started to be unraveled, pointing towards the disturbed maturation of oligodendrocytes (OLs) as a key mechanism. Immature OL precursor cells in the developing brain are believed to be highly s...
Source: Frontiers in Physiology - May 8, 2019 Category: Physiology Source Type: research

The Relationship Between Heart Rate and Left Ventricular Isovolumic Relaxation During Normoxia and Hypoxia-Asphyxia in Newborn Piglets
Background: Many asphyxiated neonates have cardiac complications including arrhythmia and contractile dysfunction. Little is known about the relationship between heart rate (HR) and diastolic function in asphyxiated neonates. We studied the relationship between HR and left ventricular isovolumic relaxation in neonatal asphyxia. Methods: Term newborn piglets were anesthetized and acutely instrumented with the placement of Millar catheter in the left ventricle. Hemodynamic parameters including HR, cardiac output, stroke volume, dP/dtmax and dP/dtmin, and isovolumic relaxation time constant (Tau) were continuously measured...
Source: Frontiers in Physiology - May 6, 2019 Category: Physiology Source Type: research

Impaired Activity of Ryanodine Receptors Contributes to Calcium Mishandling in Cardiomyocytes of Metabolic Syndrome Rats
Conclusion Principal findings of this work are that abnormal Ca2+ transient amplitude, contractile dysfunction; and impaired relaxation of MetS cardiomyocytes underlies intrinsic dysfunctional RyR2 and SERCA pump. Abnormal activity of RyRs was evidenced by its decreased ability to bind [3H]-ryanodine. Although the MetS condition does not modify RyR2 protein expression, its phosphorylation at Ser2814 is decreased, which impairs its capacity for activation during ECC. The dysfunctional RyRs, together with a decreased activity of SERCA pump due to decreased Thr17-PLN phosphorylation suggest a downregulation of CaMKII in MetS...
Source: Frontiers in Physiology - April 29, 2019 Category: Physiology Source Type: research

Age-Dependence of Flow Homeostasis in the Left Ventricle
Conclusions: In average, blood spends 1 to 3 beats inside the LV with very low shear stress rates. The apical region is the most prone to blood stasis, particularly in mid-aged adults. The washout of blood in the normal LV is age-dependent due to physiological changes in the degree of apical penetration of the filling waves. Introduction Cardioembolic stroke is a major source of mortality and disability worldwide and blood stasis one of its major determinants (Adams et al., 1986). Left ventricular (LV) function has evolved to maximize mechanical efficiency and ensure organ perfusion at a low cost of energy and fill...
Source: Frontiers in Physiology - April 25, 2019 Category: Physiology Source Type: research

Effects of Neurotrophic Factors in Glial Cells in the Central Nervous System: Expression and Properties in Neurodegeneration and Injury
Conclusion and Future Aspects This review summarizes available NTF expression data, compiles existing evidence on the effects of glial NTF signaling in healthy conditions and in disease models (Figure 1), and highlights the importance of this topic for future studies. The relationship between NTFs and glia is crucial for both the developing and adult brain. While some of these factors, such as NT-3 and CNTF, have highly potent effects on gliogenesis, others like BDNF and GDNF, are important for glia-mediated synapse formation. Neurotrophic factors play significant roles during neurodegenerative disorders. In many cases, ...
Source: Frontiers in Physiology - April 25, 2019 Category: Physiology Source Type: research

Neuromuscular and Muscle Metabolic Functions in MELAS Before and After Resistance Training: A Case Study
Conclusion To conclude, this study suggests a preserved plasticity in the skeletal muscle of a patient with MELAS. More importantly, Resistance Training appears to be a safe and effective method to increase skeletal muscle function in this patient population, and this effect is mediated by both neuromuscular and mitochondrial adaptations. However, particular attention and caution is needed in the interpretation of the data of this single case study and further studies are warranted including larger sample of patients. Ethics Statement For this case study the participant caregiver provided written informed consent. Auth...
Source: Frontiers in Physiology - April 25, 2019 Category: Physiology Source Type: research

Periodontal Disease Is Associated With Increased Risk of Hypertension: A Cross-Sectional Study
Conclusion: Periodontal disease is significantly and positively correlated with increased risk of hypertension in Chinese population, and exact mechanisms of this association should be explored in future. Introduction Periodontal disease is a complex polymicrobial inflammation, including gingivitis and periodontitis. According to the 2015 Global Burden of Disease (GBD) study, the prevalence of severe chronic periodontitis in 2015 has reached 616 million (Kassebaum et al., 2017). In China, the periodontal disease standardized DALYs rate has risen from 24.7 in 1990 to 25.7 in 2013 according to the data from 2013 GBD ...
Source: Frontiers in Physiology - April 24, 2019 Category: Physiology Source Type: research

Iron Metabolism and Brain Development in Premature Infants
Yafeng Wang1,2,3, Yanan Wu2, Tao Li1,2,3, Xiaoyang Wang2,4 and Changlian Zhu2,3* 1Department of Neonatology (NICU), Children’s Hospital Affiliated Zhengzhou University, Zhengzhou, China 2Henan Key Laboratory of Child Brain Injury, Institute of Neuroscience and Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China 3Department of Clinical Neuroscience, Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden 4Department of Physiology, Sahlgrenska Academy, Institute of Neuroscience and Physiology, University of Got...
Source: Frontiers in Physiology - April 24, 2019 Category: Physiology Source Type: research

Compensation of Respiratory-Related Postural Perturbation Is Achieved by Maintenance of Head-to-Pelvis Alignment in Healthy Humans
Conclusion Extreme lung volume variations over vital capacity is associated with changes of thoracic curvature bringing it outside the normal range, which would theoretically compromise verticality. This is however fully compensated by adaptations of the cervical curvature and pelvic tilt to preserve adequate head-to-pelvis verticality and horizontal gaze alignment. Lung volume related postural perturbations increase with age, but age did not affect head-to-pelvis alignment. Future studies are needed to investigate potential postural dysfunction in chronic respiratory diseases that induce changes of lung volume or chest g...
Source: Frontiers in Physiology - April 23, 2019 Category: Physiology Source Type: research

A Genetic Variant of miR-34a Contributes to Susceptibility of Ischemic Stroke Among Chinese Population
This study was supported by National Natural Science Foundation of China (Nos. 81560552, 81260234), Natural Science Foundation of Guangxi Zhuang Autonomous Region (CN) (2017JJA180826), Innovation Project of Guangxi Graduate Education (CN) (201601009) and Key Laboratory Open Project Fund of Guangxi Zhuang Autonomous Region (CN) (kfkt20160064). Conflict of Interest Statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Supplementary Material The Supplementary Material for this article can be fou...
Source: Frontiers in Physiology - April 23, 2019 Category: Physiology Source Type: research

Ambient Conditions Prior to Tokyo 2020 Olympic and Paralympic Games: Considerations for Acclimation or Acclimatization Strategies
This study was supported by ZonMw (Project: Thermo Tokyo: Beat the heat), Netherlands Organisation for Scientific Research (NWO) (Project: Citius, Altius, Sanius), and Heatshield, under EU Horizon 2020 grant agreement No 668786. Conflict of Interest Statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Acknowledgments The authors thank Dr. Tatsuro Amano (Niigata University, Japan) for his assistance with translating the Japanese Meteorological Agency website. Footnotes ^ https://rdrr.io/g...
Source: Frontiers in Physiology - April 23, 2019 Category: Physiology Source Type: research

Multifractal Desynchronization of the Cardiac Excitable Cell Network During Atrial Fibrillation. II. Modeling
In this study, we elaborate on a tentative interpretation of the observed intermittent dynamics during AF as the signature of synaptic plasticity. Typical individual GJC transition times between open and closed states were shown to be much longer than those of membrane polarization but compare well with membrane recovery time (≳ 100ms) (Spray et al., 1984; Neyton and Trautmann, 1986; Wang et al., 1992; Bukauskas and Verselis, 2004; Desplantez et al., 2007). Moreover, slow gating modulations have been evidenced due to cytoplasmic protons (low pH) and free calcium (Spray et al., 1984; Burt and Sray, 1988; Kumar and G...
Source: Frontiers in Physiology - April 23, 2019 Category: Physiology Source Type: research

Atrial Transcriptional Profiles of Molecular Targets Mediating Electrophysiological Function in Aging and Pgc-1 β Deficient Murine Hearts
Conclusion: These findings limit the possible roles of gene transcriptional changes in previously reported age-dependent pro-arrhythmic electrophysiologial changes observed in Pgc-1β-/- atria to an altered Ca2+-ATPase (Atp2a2) expression. This directly parallels previously reported arrhythmic mechanism associated with p21-activated kinase type 1 deficiency. This could add to contributions from the direct physiological outcomes of mitochondrial dysfunction, whether through reactive oxygen species (ROS) production or altered Ca2+ homeostasis. Introduction Atrial arrhythmias constitute a major public health pro...
Source: Frontiers in Physiology - April 23, 2019 Category: Physiology Source Type: research