Track topics on Twitter Track topics that are important to you
The investigators aim to show that quantitative analysis of doppler flow velocity waveforms i.e. ultrasound which is a non−invasive and very safe means of assessing blood flow; recorded in the proximity of terminal microvascular beds of interest, (i.e. the forearm and ocular circulation) can sensitively detect and track local changes in microvascular haemodynamics i.e. the function of the small blood vessels that are found in the back of the eye and in the forearm.
The investigators also aim to relate change in the doppler spectral flow velocity waveform i.e. the ultrasound signal, in the central retinal artery to changes in geometry and tone of the vasculature (or changes in the structure and function of small blood vessels) in response to inhaled oxygen and carbon dioxide. The geometry and tone of the vasculature (or Blood Vessels) can be measured by taking photographs of the back of the eye.
Diabetes mellitus significantly increases the risk for both small and large blood vessel complications e.g. diabetic eye problems and coronary heart disease. Vital organs such as the eye, kidney, heart and brain represent well− recognized preferential targets in patients with diabetes mellitus. The presence of such end−organ damage powerfully influences cardiovascular risk and the benefits of therapeutic interventions. Unfortunately, by the time symptoms develop or events occur as manifestations of target−organ damage, the disease process is already at an advanced stage. Although not traditionally viewed as an end−organ, it is altered structure and function of arterial small blood vessels that acts as the substrate for accelerated disease development and the increased occurrence of vascular events in patients with diabetes mellitus. The ability to detect and monitor sub−clinical damage, representing the cumulative and integrated influence of all risk factors in impairing arterial wall integrity, holds potential to further refine cardiovascular risk stratification and enable early intervention to prevent or attenuate disease progression.
Data derived from analysis of arterial waveforms, that marks the presence of impaired pulsatile function in the arterial system, has been shown to predict future cardiovascular risk. As consistent abnormalities in the arterial pulse wave shape have been recognized for many years in diabetic subjects there has been a growing interest in quantifying changes in the pulse contour to provide information about the status of the vasculature in diabetes. These original observations have been confirmed in more recent studies in patients with type 1 and type 2 diabetes mellitus and are detected prior to the development of clinical complications of the disease.
Analysis of the pulse contours recorded from sites in large conduit arteries identify structural and functional abnormalities predominantly in the systemic microvasculature, as small arteries and arterioles are recognised as the major sites for wave reflection that alters pulse contour morphology. It is recognised that techniques providing a global assessment of the circulation may not capture and cannot localise findings to a specific site or target−organ of interest in the arterial system. Microcirculation is a collective term for the smallest segments of the vascular system and is a major site of control of vascular resistance. It includes arterioles and capillaries and is considered to be a continuum rather than a distinct site of resistance control. Importantly, it is recognised as sites were the earliest manifestations of cardiovascular disease, especially inflammatory processes occur. The microvasculature may therefore constitute a preferential target or be primarily involved in the pathogenesis of disease and represents an important regional target for therapeutic interventions. Further, retinal photography and standardised grading provides a unique opportunity to study retinal microvascular characteristics including retinopathy and change in arteriolar (or blood vessel) structure and function. Improved methods of assessment to study the retinal microvascular network holds potential to improve prediction of risk, identify high risk groups and act as a window to monitor the effects of possible drug interventions.
Allocation: Non-Randomized, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Prevention
Type 1 Diabetes Mellitus
Administration ofOxygen and carbon dioxide, Administration of Oxygen and carbon dioxide
Department of Therapeutics and Pharmacology, Queens University Belfast
Queen's University, Belfast
Published on BioPortfolio: 2014-08-27T03:16:48-0400
We aim to test our method for measuring chemosensitivity (the ventilatory response to a change in carbon dioxide), which uses sinusoidal carbon dioxide stimuli. Hypotheses: - Ca...
Carbon dioxide insufflation during colonoscopy significantly reduces discomfort (pain, bloating and flatulence) after the procedure. So far, it has not been studied in inflammatory bowel d...
The purpose of this study is to determine if blowing carbon dioxide into the surgical field during open-heart surgery to displace retained chest cavity air from the atmosphere will decreas...
Endovascular repair of infrarenal abdominal aortic aneurysms (AAA) requires a contrast agent to identify the vascular anatomy and placement of the stent graft. Iodine contrast has traditi...
Investigators evaluate the effect of patient position (Trendelenburg and reverse Trendelenburg) on arterial, end-tidal and transcutaneous carbon dioxide partial pressure in patients underg...
Propofol impairs upper airway dilator muscle tone and increases upper airway collapsibility. Preclinical studies show that carbon dioxide decreases propofol-mediated respiratory depression. We studied...
Apneic oxygenation via the oral route using a buccal device extends the safe apnea time in most but not all obese patients. Apneic oxygenation techniques are most effective when tracheal oxygen concen...
The ratios of central venous to arterial carbon dioxide content and tension to arteriovenous oxygen content are not associated with overall anaerobic metabolism in postoperative cardiac surgery patients.
The aim of the present study was to evaluate the ability of the ratios of central venous to arterial carbon dioxide content and tension to arteriovenous oxygen content to predict an increase in oxygen...
Carbon dioxide is an intrinsically stable molecule. Therefore, its activation requires extra energy input in the form of reactive reagents and/or activated catalysts and, often, harsh reaction conditi...
Carbonate formation in waste from the steel industry could constitute a non-trivial proportion of global requirements to remove carbon dioxide from the atmosphere at potentially low cost. To constrain...
An enzyme with high affinity for carbon dioxide. It catalyzes irreversibly the formation of oxaloacetate from phosphoenolpyruvate and carbon dioxide. This fixation of carbon dioxide in several bacteria and some plants is the first step in the biosynthesis of glucose. EC 184.108.40.206.
A copper protein that catalyzes the formation of 2 moles of 3-phosphoglycerate from ribulose 1,5-biphosphate in the presence of carbon dioxide. It utilizes oxygen instead of carbon dioxide to form 2-phosphoglycollate and 3-phosphoglycerate. EC 220.127.116.11.
A family of zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide. They play an important role in the transport of CARBON DIOXIDE from the tissues to the LUNG. EC 18.104.22.168.
Catalyzes the decarboxylation of an alpha keto acid to an aldehyde and carbon dioxide. Thiamine pyrophosphate is an essential cofactor. In lower organisms, which ferment glucose to ethanol and carbon dioxide, the enzyme irreversibly decarboxylates pyruvate to acetaldehyde. EC 22.214.171.124.
An enzyme of the lyase class that catalyzes the conversion of ATP and oxaloacetate to ADP, phosphoenolpyruvate, and carbon dioxide. The enzyme is found in some bacteria, yeast, and Trypanosoma, and is important for the photosynthetic assimilation of carbon dioxide in some plants. EC 126.96.36.199.
Radiology is the branch of medicine that studies imaging of the body; X-ray (basic, angiography, barium swallows), ultrasound, MRI, CT and PET. These imaging techniques can be used to diagnose, but also to treat a range of conditions, by allowing visuali...
Diabetes is a lifelong condition that causes a person's blood sugar level to become too high. The two main types of diabetes are: type 1 diabetes type 2 diabetes In the UK, diabetes affects approximately 2.9 million people. There are a...