Branch Of Left Anterior Descending Artery Research Articles

Effects of Picroside II on Myocardial Ischemia-Reperfusion Injury in Streptozotocin-Induced Diabetic Rats

Objective: Diabates mellitus, is a chronic metabolic disorder accompanied by an increase in oxidative stress. Ischemia-reperfusion injury is a cascade of events initiated by tissue ischemia. The cellular damage produced by reperfusion leads to an active inflammatory response. This study was performed to investigate the effect of picroside II on myocardial ischemia-reperfusion injury in rats with streptozotocin-induced diabetes. Methods: Animals were equally (n:6) divided for five groups as follows; Control (C), diabetes [D], diabetes+picroside II [DP], diabetes+I/R [DIR], and diabetes+I/R+ picroside II [DIRP]. In DIR group, a left anterior descending artery branch was occluded for 60 minutes, the reperfused for 120 minutes. In DIRP group, picroside II was administrated via 10 mg/kg intraperitoneal route 30 minutes before ligating the left anterior descending artery. At the end of the study, myocardial tissues were taken for total oxidant status and total antioxidant status level determinations. Results: Total oxidant status levels were significantly higher in DIR group, when compared with C, DP, and DIRP groups (p:0.001, p:0.019, and p:0.031, respectively). Total antioxidant status levels were significantly higher in DIR group, when compared with C, DP, and DIRP groups (p:0.006, p:0.024, and p:0.007, respectively). Conclusion: These results indicate that administration of picroside II may have protective effects against I/R injury.

The Interaction of Mast Cells and Cardiac Sympathetic Nerves During Acupuncture in Acute Myocardial Ischemia Rats

Abstract Background: Acupuncture has been shown to regulate visceral functions. However, the specific mechanism remains unknown. Objective: This study attempted to investigate cardiac sympathetic nerve activity response to acupuncture and its activation effect on mast cells in the acupoint area. Materials and Methods: A rat model of acute myocardial ischemia (AMI) was prepared by ligating the left anterior descending artery branch. After dissecting a branch of the cardiac sympathetic nerves, the left Neiguan point (PC 6) was stimulated with acupuncture. Then, the skin tissues of acupoint area were sampled and stained with neutral red after killing the rats. Main Outcome Measures: Nerve discharges and electrocardiograph readings were recorded during acupuncture. Heart rate variability (HRV) and the power spectrum of nerve discharges were used as markers for analysis. Ratios of degranulated to total mast cells were also calculated. Results: AMI caused an increase in the ratio of low frequency/high frequency...

Hemoglobin plus myoglobin concentrations and near infrared light pathlength in phantom and pig hearts determined by diffuse reflectance spectroscopy

To noninvasively determine absolute concentrations of hemoglobin (Hb) plus myoglobin (Mb) in cardiac tissue by means of regular near infrared (NIR) light diffuse reflectance measurements, a first derivative approach was applied. The method was developed to separately calculate oxygenated and deoxygenated [Hb + Mb] as well as an effective pathlength, which NIR light passes through in the tissue between optodes. Applying a cotton wool-based phantom, which mimics muscle tissue, it was shown that the intensity of the pseudo-optical density first derivative depends linearly on both oxygenated and deoxygenated Hb concentration, thereby validating the Lambert–Beer law in the range of 0 to 0.25 mM tetrameric Hb. A high correlation ( R = 0.995) was found between concentrations of Hb loaded onto the phantom and those determined spectrophotometrically, thereby verifying the first derivative method validity. The efficiency of the method was tested using in vivo pig hearts prior to and after ischemia initiated experimentally by left anterior descending artery branches occlusion. The results showed that the total [Hb + Mb] was 0.9–1.2 mM heme, the average tissue oxygen saturation was approximately 70% (which reduced to nearly 0% after occlusion), and the NIR (700–965 nm) light pathlength was 2.3 mm (differential pathlength factor [DPF] = 2.7–2.8) in a living heart tissue.

Differential response of large and small coronary arteries to nitroglycerin and angiotensin. Autoregulation and tachyphylaxis.

Large proximal and smaller distal coronary arteries respond differently to pharmacologic agents, but the role of autoregulation is not known. We examined this role in dogs by cannulating the main left coronary artery and a distal left anterior descending artery branch. With coronary flow held constant, the distal coronary artery pressure and the gradient from proximal to distal artery were proportional to the small and the large vessel resistance, respectively. At normal perfusion pressure, nitroglycerin injected directly into the coronary artery caused a transient fall in small vessel resistance and a prolonged decrease in large vessel resistance. During ischemia, when small vessels autoregulated and small vessel resistance was minimal, nitroglycerin lowered only large vessel resistance. Angiotensin injected directly into the coronary artery increased small and large vessel resistance; the slower response of large vessel resistance followed a passive dilation caused by increased perfusion pressure. Continuous infusions of nitroglycerin and angiotensin maintained dilation and constriction of large vessels, respectively, but small vessels demonstrated tachyphylaxis. Only adenosine infusion maintained dilation in both large and small vessels. In response to varying perfusion, small vessels autoregulated and large vessels responded passively to changes in perfusion pressure. We concluded that small coronary arteries respond to cardiac metabolism and demonstrate escape from prolonged dilation and constriction. Conversely, large vessels respond continuously to sustained mechanical and pharmacologic stimuli independently of the nutritional state of the myocardium.