scholarly journals Application of Echocardiography on Transgenic Mice with Cardiomyopathies

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
G. Chen ◽  
Y. Li ◽  
J. Tian ◽  
L. Zhang ◽  
P. Jean-Charles ◽  
...  
Keyword(s):  
Heart Failure ◽  
Transgenic Mice ◽  
Tissue Doppler ◽  
Doppler Imaging ◽  
Cellular Mechanisms ◽  
Embryonic Mouse ◽  
Experimental Animals ◽  
Therapeutic Outcomes ◽  
And Function

Cardiomyopathies are common cardiac disorders that primarily affect cardiac muscle resulting in cardiac dysfunction and heart failure. Transgenic mouse disease models have been developed to investigate the cellular mechanisms underlying heart failure and sudden cardiac death observed in cardiomyopathy cases and to explore the therapeutic outcomes in experimental animals in vivo. Echocardiography is an essential diagnostic tool for accurate and noninvasive assessment of cardiac structure and function in experimental animals. Our laboratory has been among the first to apply high-frequency research echocardiography on transgenic mice with cardiomyopathies. In this work, we have summarized our and other studies on assessment of systolic and diastolic dysfunction using conventional echocardiography, pulsed Doppler, and tissue Doppler imaging in transgenic mice with various cardiomyopathies. Estimation of embryonic mouse hearts has been performed as well using this high-resolution echocardiography. Some technical considerations in mouse echocardiography have also been discussed.

scholarly journals p90 ribosomal S6 kinase 3 contributes to cardiac insufficiency in α-tropomyosin Glu180Gly transgenic mice

2013 ◽  
Vol 305 (7) ◽  
pp. H1010-H1019 ◽  
Author(s):  
Catherine L. Passariello ◽  
Marjorie Gayanilo ◽  
Michael D. Kritzer ◽  
Hrishikesh Thakur ◽  
Zoharit Cozacov ◽  
...  
Keyword(s):  
Heart Failure ◽  
Transgenic Mice ◽  
Cardiac Function ◽  
Interstitial Fibrosis ◽  
Cardiac Insufficiency ◽  
S6 Kinase ◽  
Transgenic Expression ◽  
P90 Ribosomal S6 Kinase ◽  
Ribosomal S6 Kinase

Myocardial interstitial fibrosis is an important contributor to the development of heart failure. Type 3 p90 ribosomal S6 kinase (RSK3) was recently shown to be required for concentric myocyte hypertrophy under in vivo pathological conditions. However, the role of RSK family members in myocardial fibrosis remains uninvestigated. Transgenic expression of α-tropomyosin containing a Glu180Gly mutation (TM180) in mice of a mixed C57BL/6:FVB/N background induces a cardiomyopathy characterized by a small left ventricle, interstitial fibrosis, and diminished systolic and diastolic function. Using this mouse model, we now show that RSK3 is required for the induction of interstitial fibrosis in vivo. TM180 transgenic mice were crossed to RSK3 constitutive knockout ( RSK3−/−) mice. Although RSK3 knockout did not affect myocyte growth, the decreased cardiac function and mild pulmonary edema associated with the TM180 transgene were attenuated by RSK3 knockout. The improved cardiac function was consistent with reduced interstitial fibrosis in the TM180; RSK3−/− mice as shown by histology and gene expression analysis, including the decreased expression of collagens. The specific inhibition of RSK3 should be considered as a potential novel therapeutic strategy for improving cardiac function and the prevention of sudden cardiac death in diseases in which interstitial fibrosis contributes to the development of heart failure.

scholarly journals Reduced myocardial reserve in cirrhotic patients: an evaluation by dobutamine stress speckle tracking and tissue Doppler imaging (TDI) echocardiography

2019 ◽  
Vol 11 (2) ◽  
pp. 127-131 ◽  
Author(s):  
Mahmood Zamirian ◽  
Forough Afsharizadeh ◽  
Alireza Moaref ◽  
Firoozeh Abtahi ◽  
Fatemeh Amirmoezi ◽  
...  
Keyword(s):  
Heart Failure ◽  
Strain Rate ◽  
Speckle Tracking ◽  
Systolic Function ◽  
Peak Stress ◽  
Tissue Doppler ◽  
Doppler Imaging ◽  
Control Group ◽  
Basal Segment ◽  
Cirrhotic Patients

Introduction: Despite the normal systolic function at rest, cirrhotic patients often suffer from volume overload and symptoms of heart failure as they face stressful situations. This study investigated the myocardial reserve in cirrhotic patients at resting condition and peak stress by dobutamine speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI). Methods: Twenty cirrhotic patients and 10 normal individuals aged 30-50 were selected randomly. For all of the participants, complete echocardiographic study of 2D, STE and TDI was done at rest and peak stress status with dobutamine. The following parameters were assessed: ejection fraction (EF), global longitudinal LV strain (GLS), strain rate in the septal basal segment and lateral wall and E’ in the septal basal segment by color-coded method. Results: At baseline, EF was higher than 55% in both groups. GLS was higher (-22.6±2.4%) in the case group than the control group (-19.2±1.9%) at resting condition. After stress, it showed a greater increase (-22.5±1.7%) in the controls compared to cirrhotic patients (-22.6±3.3%; mean difference = 2.6 ± 2.03, P = 0.02). In cirrhotic patients, the average strain rate in the basal septal segment decreased after stress (-1.2 ± 0.3/s to-1.1 ± 0.3/s), but it increased in the control group (-1.1 ± 0.2/s to -1.8 ± 0.2/s). Conclusion: Despite the presence of normal resting systolic function in cirrhotic patients, there was insufficient increase or even a decrease in myocardial function with stress; this may indicate the absence of sufficient myocardial reserve in cirrhotic patients. These findings would help to explain the reason for occurrence of heart failure or hemodynamic changes in cirrhotic patients.

scholarly journals Molecular mechanisms of olfactory detection in insects: beyond receptors

Open Biology ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 200252
Author(s):  
Hayden R. Schmidt ◽  
Richard Benton
Keyword(s):  
Molecular Mechanisms ◽  
Olfactory Receptors ◽  
Environmental Chemicals ◽  
Ecological Niches ◽  
Cellular Mechanisms ◽  
Signalling Molecules ◽  
Olfactory Systems ◽  
Lymph Fluid ◽  
And Function

Insects thrive in diverse ecological niches in large part because of their highly sophisticated olfactory systems. Over the last two decades, a major focus in the study of insect olfaction has been on the role of olfactory receptors in mediating neuronal responses to environmental chemicals. In vivo , these receptors operate in specialized structures, called sensilla, which comprise neurons and non-neuronal support cells, extracellular lymph fluid and a precisely shaped cuticle. While sensilla are inherent to odour sensing in insects, we are only just beginning to understand their construction and function. Here, we review recent work that illuminates how odour-evoked neuronal activity is impacted by sensillar morphology, lymph fluid biochemistry, accessory signalling molecules in neurons and the physiological crosstalk between sensillar cells. These advances reveal multi-layered molecular and cellular mechanisms that determine the selectivity, sensitivity and dynamic modulation of odour-evoked responses in insects.

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