Search results for "rhythm"

Detailed Anatomical and Electrophysiological Models of Human Atria and Torso for the Simulation of Atrial Activation

2015

Atrial arrhythmias, and specifically atrial fibrillation (AF), induce rapid and irregular activation patterns that appear on the torso surface as abnormal P-waves in electrocardiograms and body surface potential maps (BSPM). In recent years both P-waves and the BSPM have been used to identify the mechanisms underlying AF, such as localizing ectopic foci or high-frequency rotors. However, the relationship between the activation of the different areas of the atria and the characteristics of the BSPM and P-wave signals are still far from being completely understood. In this work we developed a multi-scale framework, which combines a highly-detailed 3D atrial model and a torso model to study th…

Nocturnin in the demosponge Suberites domuncula: a potential circadian clock protein controlling glycogenin synthesis in sponges

2012

Sponges are filter feeders that consume a large amount of energy to allow a controlled filtration of water through their aquiferous canal systems. It has been shown that primmorphs, three-dimensional cell aggregates prepared from the demosponge Suberites domuncula and cultured in vitro , change their morphology depending on the light supply. Upon exposure to light, primmorphs show a faster and stronger increase in DNA, protein and glycogen content compared with primmorphs that remain in the dark. The sponge genome contains nocturnin, a light/dark-controlled clock gene, the protein of which shares a high sequence similarity with the related molecule of higher metazoans. The sponge nocturnin …

Crystal structure of vinorine synthase, the first representative of the BAHD superfamily.

2005

Vinorine synthase is an acetyltransferase that occupies a central role in the biosynthesis of the antiarrhythmic monoterpenoid indole alkaloid ajmaline in the plant Rauvolfia. Vinorine synthase belongs to the benzylalcohol acetyl-, anthocyanin-O-hydroxy-cinnamoyl-, anthranilate-N-hydroxy-cinnamoyl/benzoyl-, deacetylvindoline acetyltransferase (BAHD) enzyme superfamily, members of which are involved in the biosynthesis of several important drugs, such as morphine, Taxol, or vindoline, a precursor of the anti-cancer drugs vincaleucoblastine and vincristine. The x-ray structure of vinorine synthase is described at 2.6-angstrom resolution. Despite low sequence identity, the two-domain structure…

Interaction of Circadian Clock Proteins CRY1 and PER2 Is Modulated by Zinc Binding and Disulfide Bond Formation

2014

SummaryPeriod (PER) proteins are essential components of the mammalian circadian clock. They form complexes with cryptochromes (CRY), which negatively regulate CLOCK/BMAL1-dependent transactivation of clock and clock-controlled genes. To define the roles of mammalian CRY/PER complexes in the circadian clock, we have determined the crystal structure of a complex comprising the photolyase homology region of mouse CRY1 (mCRY1) and a C-terminal mouse PER2 (mPER2) fragment. mPER2 winds around the helical mCRY1 domain covering the binding sites of FBXL3 and CLOCK/BMAL1, but not the FAD binding pocket. Our structure revealed an unexpected zinc ion in one interface, which stabilizes mCRY1-mPER2 int…

Treadmill Training Effect on the Myokines Content in Skeletal Muscles of Mice With a Metabolic Disorder Model

2021

The effect of treadmill training loads on the content of cytokines in mice skeletal muscles with metabolic disorders induced by a 16 week high fat diet (HFD) was studied. The study included accounting the age and biorhythmological aspects. In the experiment, mice were used at the age of 4 and 32 weeks, by the end of the experiment—respectively 20 and 48 weeks. HFD feeding lasted 16 weeks. Treadmill training were carried out for last 4 weeks six times a week, the duration 60 min and the speed from 15 to 18 m/min. Three modes of loading were applied. The first subgroup was subjected to stress in the morning hours (light phase); the second subgroup was subjected to stress in the evening hours …

The development of rhythm at the age of 6–11 years: non-pitch rhythmic improvisation

2006

In the statistical and transcriptional analyses reported in this exploratory study, original rhythms of 6–11-year-old children (N = 36) were examined. The hypotheses were based on a new model of musical development, and tested empirically using non-pitch rhythmic improvisation in a MIDI-environment. Several representational types were found in cluster analysis. The types are comparable to those found in earlier studies of rhythm. A dimensional conflict appeared between grouping and metre, and was solved in the last substage (10–11 years). Age was found to be a significant factor in the development of the hierarchy of form, the amount of different rhythm patterns, the metrical hierarchy, as …

Rhythmicity of Intestinal IgA Responses Confers Oscillatory Commensal Microbiota Mutualism

2021

ABSTRACTMutualistic interactions with the commensal microbiota are enforced through a range of immune responses that confer metabolic benefits for the host and ensure tissue health and homeostasis. Immunoglobulin (Ig)A responses directly determine the composition of commensal species that colonize the intestinal tract but require significant metabolic resources to fuel antibody production by tissue-resident plasma cells. Here we demonstrate IgA responses are subject to diurnal regulation by dietary-derived metabolic cues and a cell-intrinsic circadian clock. Rhythmicity in IgA secretion conferred oscillatory patterns on the commensal microbial community and its associated metabolic activity…

Assessment of blood pressure early morning rise

2002

Myocardial bridge pathology and preventable accidents during physical activity of healthy subjects: A case report and a literature review.

2020

Myocardial bridging is a congenital coronary pathology described as a segment of coronary artery which courses through the myocardial wall under the muscle bridge. Although the prognosis of myocardial bridging is benign, sports medicine recognises myocardial bridging as a leading cause of sudden death among young basketball, football and soccer players. The authors report a case of a 42-year-old man who collapsed while playing football. He died notwithstanding prompt medical assistance and cardiopulmonary resuscitation. At autopsy, gross examination of the heart revealed the intramural course of the left anterior descending coronary artery to be 2 cm from its coronary ostial origin. Histol…

Non-alcoholic Fatty pancreas disease pathogenesis: a role for developmental programming and altered circadian rhythms.

2014

OBJECTIVES: Emerging evidence suggests that maternal obesity (MO) predisposes offspring to obesity and the recently described non-alcoholic fatty pancreas disease (NAFPD) but involved mechanisms remain unclear. Using a pathophysiologically relevant murine model, we here investigated a role for the biological clock - molecular core circadian genes (CCG) in the generation of NAFPD. DESIGN: Female C57BL6 mice were fed an obesogenic diet (OD) or standard chow (SC) for 6 weeks, prior to pregnancy and throughout gestation and lactation: resulting offspring were subsequently weaned onto either OD (Ob_Ob and Con_Ob) or standard chow (Ob_Con and Con_Con) for 6 months. Biochemical, pro-inflammatory a…