Contractility detection of isolated mouse papillary muscle using myotronic Myostation-Intact device.

BACKGROUND: To understand the relationship between myocardial contractility and external stimuli, detecting ex vivo myocardial contractility is necessary. METHODS: We elaborated a method for contractility detection of isolated C57 mouse papillary muscle using Myostation-Intact system under different frequencies, voltages, and calcium concentrations. RESULTS: The results indicated that the basal contractility of the papillary muscle was 0.27 ± 0.03 mN at 10 V, 500-ms pulse duration, and 1 Hz. From 0.1 to 1.0 Hz, contractility decreased with an increase in frequency (0.45 ± 0.11-0.10 ± 0.02 mN). The voltage-initiated muscle contractility varied from 3 to 6 V, and the contractility gradually increased as the voltage increased from 6 to 10 V (0.14 ± 0.02-0.28 ± 0.03 mN). Moreover, the muscle contractility increased when the calcium concentration was increased from 1.5 to 3 mM (0.45 ± 0.17-1.11 ± 0.05 mN); however, the contractility stopped increasing even when the concentration was increased to 7.5 mM (1.02 ± 0.23 mN). CONCLUSIONS: Our method guaranteed the survivability of papillary muscle ex vivo and provided instructions for Myostation-Intact users for isolated muscle contractility investigations.

Giant Interatrial Septal Lipoma Filling the Right Atrium Causing Slight Symptoms: A Case Report.

Cardiac lipoma is extremely rare. Here, we present a unique illustrative case of an interatrial septal lipoma protruding into the right atrium, causing symptoms in a 54-year-old male. Echocardiogram and computed tomography showed a well-shaped, giant, and fixed mass located in the interatrial septum and right atrium. The only manifestation was palpitation, though the mass filled almost all of the atrium and compressed the superior vena cava. The patient received resection of the large-sized lipoma, which was 87mm in diameter and weighed 300-400g. Pathological exam demonstrated mature lipocytes and substantiated the diagnosis of lipoma. The patient did well postoperatively, and symptoms were resolved.

Mild hypothermia in rat with acute myocardial ischaemia-reperfusion injury complicating severe sepsis.

Myocardial ischemia-reperfusion injury (MIRI) with concurrent severe sepsis has led to substantial mortality. Mild hypothermia (MHT) has been proved to have a therapeutic effect in either MIRI or severe sepsis, which suggests it might be beneficial for MIRI complicating severe sepsis. In this study, Sprague-Dawley rats with MIRI complicating severe sepsis were allotted in either MHT (33 ± 0.5°C) group or normothermia (NT, 37 ± 0.5°C) group; as control, rats receiving sham surgery and normal saline were kept at NT. After 2h of temperature maintenance, blood and heart tissue were acquired for detections. Lactate dehydrogenase (LDH) and MB isoenzyme of creatine kinase (CK-MB) in blood, triphenyl tetrazolium chloride and Evans blue staining, hematoxylin and eosin staining for myocardium were employed to detect myocardial damage. Tumor necrosis factor (TNF)-α and caspase-3 was performed by immunohistochemistry to exam myocardial inflammation and apoptosis. Detection of NADPH oxidase (NOX) 2 was for myocardial oxidative stress. In MHT group, systolic blood pressure was improved significantly compared with NT group. Myocardial infarct size, morphological change, LDH and CK-MB levels were attenuated compared to NT group. Moreover, less expressions of TNF-α, caspase-3 and NOX2 in MHT group were presented compared with NT group. MHT showed cardioprotection by improving cardiac dysfunction, reducing myocardial infarct size and attenuating myocardial injury, inflammation, apoptosis and oxidative stress.

Current status of mild hypothermia therapy for cardiac dysfunction with sepsis / 解放军医学杂志

Cardiac dysfunction (CD) combined with sepsis leads to increase in mortality in intensive care unit (ICU). Currently, the clinical treatment of CD with sepsis is the combination of delaying heart failure and anti-sepsis therapeutics. Mild therapeutic hypothermia (MTH) may decrease the body temperature to 32-35 ℃, improve symptom and decrease mortality in patients with CD and animal with sepsis. MTH has been used in animal models of heart failure and sepsis with pronounced outcomes and reduced mortality. However, it remains controversial if MTH can be used in treating patients with CD and sepsis due to its side effects, although the effectiveness of MTH on CD and sepsis has been testified. The present article reviews the application of MTH on animal researches, clinical use for treatment of patients with CD and sepsis, the effect and possible mechanisms of temperature on heart and sepsis, as well as the effect of MTH onto other organs and coagulation function.