View clinical trials related to Vasodilation.
Filter by:Forty-six consecutive patients undergoing elective primary coronary artery bypass grafting were enrolled. After the left IMA was harvested, free flow was measured under controlled hemodynamic conditions before any intervention (flow 1) and at a mean of 12.5 minutes after the topical application of one of three agents (milrinone, nitroglycerin or normal saline) on the IMA (flow 2).
This study aims to investigate sex differences in blood pressure control associated with exposure to acute hypoxia (low oxygen), and short term acclimatization to hypoxia at high altitude.
Application of vibration has been previously shown to affect tissue perfusion and utilized in different branches of medicine. Little is known about the acute impact of vibration application on peripheral artery hemodynamics. In this study, investigators intend to assess: 1. vibration induced hemodynamic changes in brachial artery in non-diabetic patients and compare the characteristics of these alterations with flow mediated dilation mediated changes in same cohort. 2. compare the characteristics of vibration mediated hemodynamic alterations in diabetic and non-diabetic subgroups.
The overall goal of this project is to better understand the effect of intermittent hypoxia (IH) on sympathetic neuronal discharge patterns in humans, as well as mechanisms that mediate persistent sympathoexcitation with IH.
This study aims to investigate sex differences in blood pressure control associated with exposure to acute hypoxia (low oxygen), and short term acclimatization to hypoxia at high altitude.
The CarMA (Carbon Monoxide and Altitude) Study aims to observe the vascular effects of carbon monoxide exposure at low and high altitudes.
Adipose tissue is an active endocrine organ producing several hormones with circulatory and metabolic effects. In 1994, the hormone leptin was discovered. The lack of this hormone explained extreme obesity in rare patients and parenteral substitution restored body weight and metabolic disturbances. It was however soon discovered that most humans had too high levels which were related to development of cardiovascular diseases and diabetes. It was hypothesised that leptin induced vessel dysfunction which could explain this association. In this study, we wanted to examine the association between leptin and vessel function by using the venous occlusion plethysmography method. We used three protocols to evaluate this association. First protocol. In ten healthy males, leptin was infused locally in the forearm and forearm blood flow (FBF) was measured. Second protocol. In ten healthy males, leptin or normal saline was infused locally in the forearm and FBF was measured. Concomitantly, four vasodilatators were infused locally in the forearm in a randomised order and the response (blood flow and fibrinolysis) was measured. Third protocol. In eighty-three patients with known coronary artery disease, three vasodilators were infused locally in the forearm in a random order and response (FBF and fibrinolysis) was measured. The response was related to endogenous leptin levels. The two first protocols were performed in Umeå, Sweden whereas the third was performed in Edinburgh, UK, all in 2006.
This study is a pharmacodynamic proof of concept study investigating the physiological effects of systemic infusion of nitrite on coronary blood flow using MRI.
Acutely, during different bouts of passive stretching (PS), blood flow (Q ̇) and shear rate ( ) in the feeding artery of the stretched muscles increases during the first two elongations and then it reduces during the following bouts. This hyperemic response during the first two elongations is mediated by the local release of vasoactive molecules (e.g. nitric oxide, NO). This phenomenon disappears during the following elongations due to the NO and other vasoactive molecule depletion. The relaxation phase between stretching bouts, instead, is always characterized by hyperemia as results of stretch-induced peripheral resistances decrease. Whether chronic PS administration may influence vascular function is still a matter of investigation. The hypothesis is that repetitive PS-induced Q ̇ and changes may be an enough stimulus to provoke increments in NO bioavailability, thus improving vasomotor response.
Microcirculatory flow is subject to cyclic changes under the influence of heart rate, respiration, myogenic activity, neurogenic factors and endothelial factors. Microcirculatory oscillations (vasomotion) contribute significantly to tissue perfusion. Vasomotion analysis allowed to discriminate normoglycemic subjects, prediabetic subjects and diabetic subjects. Furthermore, changes in vasomotion can precede the emergence of global signs of microangiopathy complications in type 2 diabetes. In fact, few studies reported impaired vasomotion in type 2 diabetes with peripheral neuropathy. Vasomotion analysis after vasodilator (6-min walking test and hyperthermia) and after vasoconstrictor (foot lowering) stimulus could be an effective diagnostic tool to sharpen the diagnostic. Objectives and Methodology: to study vasomotion at baseline and after exercise, hyperthermia and foot lowering within 3 groups of patients: diabetic without peripheral neuropathy, diabetic with subclinical peripheral neuropathy and diabetic with peripheral neuropathy and one group of sex- age- and body mass index-matched healthy control subjects. All the subjects will benefit from a clinical, anthropometric, level of physical activity and biological evaluations. Type 2 diabetes participants will benefit from neuropathy evaluation. In addition, cutaneous microcirculation (perfusion and vasomotion) by means of Laser Doppler Flowmetry and Laser Speckle Imaging will be recorded at rest and after different stimuli (exercise, hyperthermia and foot lowering).