scholarly journals Small heart sign

2020 ◽  
Author(s):  
Bahman Rasuli ◽  
Balint Botz
Keyword(s):  
Small Heart

Prematurity and Small Heart Volume

2008 ◽  
Vol 52 ◽  
pp. 37-42
Author(s):  
Hjördis Robbe ◽  
Inga Rune
Keyword(s):  
Heart Volume ◽  
Small Heart

Abstract 5501: Reduced Coronary Reserve as a Mechanism in Beta-Adrenergic Receptor Mediated Cardiomyopathy and its Rescue by Adenylyl Cyclase Type 5 Knockout

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Shumin Gao ◽  
Lin Yan ◽  
Chull Hong ◽  
Xin Zhao ◽  
Li Chen ◽  
...  
Keyword(s):  
Adenylyl Cyclase ◽  
Mouse Models ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Potential Mechanism ◽  
Wild Type ◽  
Coronary Reserve ◽  
Small Heart ◽  
Cardinal Feature ◽  
Adenylyl Cyclase Type 5

Reduced coronary reserve (CR) is a cardinal feature of human cardiomyopathy, but it has not been studied extensively in mouse models of cardiomyopathy, potentially because of difficulties inherent to measuring CR in such a small heart. The first goal of this study was to determine if reduced CR is a potential mechanism involved in a transgenic (Tg) mouse model of cardiomyopathy, induced by cardiac overexpression of beta 2 -adrenergic receptors (beta 2 -AR Tg). Older beta 2 -AR Tg mice (16–17 months, n=7) developed cardiomyopathy, as reflected by decreased LV ejection fraction (LVEF, 50±7%), and increased fibrosis (5.2±0.4%) and apoptosis (3.8±0.6%). CR was obtained by measuring LV coronary blood flow at baseline and with adenosine (160 microg/kg/min) induced hyperemia using high resolution ultrasound (Vevo 770). CR was significantly decreased in beta 2 -AR Tg (1.8±0.2) compared with wild type (WT) (3.0±0.3, n=6). The next goal was to determine if the rescue of the beta 2 -AR Tg cardiomyopathy resulted in a rescue of reduced CR. Since adenylyl cyclase type 5 knockout (AC5 KO) mice are protected against catecholamine stress and the development of heart failure (HF), and exhibit enhanced CR (3.7±0.4, n=5), we hypothesized that mating these mice with beta 2 -AR Tg might rescue the cardiomyopathy. Older (16–17 months, n=4) bigenic mice (beta 2 -AR Tg x AC5 KO) demonstrated a rescue of cardiomyopathy, as reflected by normalized LVEF (71±1%) and levels of apoptosis (0.11±0.01%) and fibrosis (1.09±0.33%), similar to WT. In these mice, CR was also normalized (3.4±0.6). Reduced CR in beta 2 -AR Tg cardiomyopathy is similar to that observed in large mammalian models, and in patients with cardiomyopathy. Thus, this mechanism is important to consider in mouse models of cardiomyopathy, in general, and also in particular for the mechanism of the rescue of the beta 2 -AR Tg cardiomyopathy by AC5 KO.

scholarly journals Roles of Physiological Responses and Anthropometric Factors on the Gravitational Force Tolerance for Occupational Hypergravity Exposure

2020 ◽  
Vol 17 (21) ◽  
pp. 8061
Author(s):  
Min-Yu Tu ◽  
Hsin Chu ◽  
Hsin-Hui Chen ◽  
Kwo-Tsao Chiang ◽  
Je-Ming Hu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Odds Ratio ◽  
Adjusted Odds Ratio ◽  
Gravitational Force ◽  
Physiological Responses ◽  
Lower Body ◽  
Student Pilots ◽  
Small Heart ◽  
Military Pilots ◽  
G Tolerance

Gravity in the head-to-toe direction, known as +Gz (G force), forces blood to pool in the lower body. Fighter pilots experience decreases in blood pressure when exposed to hypergravity in flight. Human centrifuge has been used to examine the G tolerance and anti-G straining maneuver (AGSM) techniques of military pilots. Some factors that may affect G tolerance have been reported but are still debated. The aim of this study was to investigate the physiological responses and anthropometric factors correlated with G tolerance. We retrospectively reviewed the training records of student pilots who underwent high G training. Variables were collected to examine their correlations with the outcome of 7.5G sustained for 15 s (7.5G profile). There were 873 trainees who underwent 7.5G profile training, 44 trainees (5.04%) could not sustain the test for 15 s. The group with a small heart rate (HR) increase (less than 10%) during the first 1–5 s of the 7.5G profile had a nearly ten-fold higher failing chance compared with the large HR increase group (adjusted odds ratio: 9.91; 95% confidence interval: 4.11–23.88). The chances of failure were inversely related to the HR increase percentage (p for trend <0.001). Factors, including body mass index, relaxed and straining G tolerance, and AGSM, were found to be negatively correlated with the outcome.

scholarly journals Aerobic performance in tinamous is limited by their small heart. A novel hypothesis in the evolution of avian flight

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Jordi Altimiras ◽  
Isa Lindgren ◽  
Lina María Giraldo-Deck ◽  
Alberto Matthei ◽  
Álvaro Garitano-Zavala
Keyword(s):  
Aerobic Performance ◽  
Avian Flight ◽  
Small Heart

scholarly journals Small Heart Syndrome in Patients with Chronic Fatigue Syndrome

2008 ◽  
Vol 31 (7) ◽  
pp. 328-333 ◽  
Author(s):  
Kunihisa Miwa ◽  
Masatoshi Fujita
Keyword(s):  
Chronic Fatigue Syndrome ◽  
Chronic Fatigue ◽  
Fatigue Syndrome ◽  
Small Heart

scholarly journals THE FINE STRUCTURE OF CAPILLARIES AND SMALL ARTERIES

1957 ◽  
Vol 3 (3) ◽  
pp. 457-462 ◽  
Author(s):  
Dan H. Moore ◽  
Helmut Ruska
Keyword(s):  
Smooth Muscle ◽  
Fine Structure ◽  
Direct Contact ◽  
Plasma Membranes ◽  
Muscle Layer ◽  
Transport Mechanisms ◽  
Small Arteries ◽  
Small Heart ◽  
Capillary Walls ◽  
Filtration Diffusion

Details of capillary endothelia of the mammalian heart are described and compared with capillaries of other organs and tissues. Continuous invagination and pinching off of the plasma membrane to form small vesicles which move across the cytoplasm are suggested as constituting a means of active and selective transmission through capillary walls (12). This might be designated as cytopempsis (transmission by cell). The fine structure of the different layers in the walls of small heart arteries is demonstrated. Endothelial protrusions extend through windows of the elestica interna to make direct contact with smooth muscle plasma membranes. The elastica interna appears to vary greatly in both thickness and density, and probably restricts filtration, diffusion, and osmosis to such an extent that windows and the transport mechanisms described (cytopempsis) are necessary for the functional integrity of the smooth muscle layer. The contractile material consists of very fine, poorly oriented filaments.

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