Search results for "Circulation"
showing 10 items of 1137 documents
Coronary microvascular dysfunction
2020
Patients with coronary microvascular dysfunction (CMVD) represent a widespread population and despite the good prognosis, many of them have a poor quality of life with strong limitations in their daily activities because of the angina symptoms. This article summarizes the most frequent clinical presentation pictures like stable and unstable microvascular angina. Main risk factors are discussed, followed by the latest updates on the subject about different pathogenic hypotheses, diagnosis and treatment. Not very well understood microvascular alterations, like slow flow phenomenon and no reflow are discussed and both prognosis and the impact of the disease in the quality of life are analyzed.
Echocardiographic assessment of coronary microvascular dysfunction: Basic concepts, technical aspects, and clinical settings
2021
Abstract Coronary flow reserve is the capacity of the coronary circulation to augment the blood flow in response an increase in myocardial metabolic demands and has a powerful prognostic significance in different clinical situations. It might assess with invasive and noninvasive technique. Transthoracic echocardiography Doppler is an emerging diagnostic technique, noninvasive, highly feasible, safe for patient and physician, without radiation, and able to detect macrovascular and microvascular anomalies in the coronary circulation. This review aims to describe the benefit and limits of echocardiographic assessment of coronary flow reserve.
Brain energy metabolism in global brain oedema.
1978
Different degrees of severity in global brain oedema were induced by varying amounts of water intoxication (50, 100, 150, and 200 ml Aqua dest./kg b.wt. intravenously) in groups of six cats, which were functionally nephrectomized. Animals loaded with physiological saline and sham-operated served as controls. Two hours following the water load, the tissue concentrations of CrP, ATP, ADP, AMP, pyruvate, glucose, and lactate were determined by optical enzymatic analysis. The results show disturbances in brain energy metabolism dependent on the severity of the brain oedema. The high energy compounds and in consequence the ATP/ADP-ratio, and respectively the energy charge potential, fall in dire…
Dexamethasone suppresses eNOS and CAT-1 and induces oxidative stress in mouse resistance arterioles
2004
Long-term treatment with glucocorticoids is associated with mild to moderate hypertension. We reported previously that downregulation of endothelial NO synthase (eNOS) expression and activity is likely to contribute to this increase in blood pressure. In the present study, we tested the effects of dexamethasone on the vasodilation of microvascular arterioles using implanted dorsal skin-fold chambers in anesthetized C57BL/6J mice. Experiments were performed on control mice or on mice treated with dexamethasone (0.1–3 mg/kg of body wt). Endothelium-dependent vasodilation in response to ACh (0.1–10 μM) was reduced by dexamethasone in a dose-dependent fashion. Comparable inhibition was seen in …
Endothelial function testing and cardiovascular disease: focus on peripheral arterial tonometry
2014
During recent decades, a number of methods have been developed to assess endothelial function, contributing to a better understanding of the pathophysiology of cardiovascular disease. Recently, the advent of noninvasive, reproducible techniques for assessment of endothelial function has opened novel possibilities of application in the clinical setting. Peripheral arterial tonometry is a relatively novel, user-friendly technique measuring finger pulse volume amplitude changes induced by reactive hyperemia following 5 minutes of ischemia in the upper limb. Current evidence indicates that this technique has the potential to significantly impact the field of cardiovascular research and preventi…
PaO2oscillations caused by cyclic alveolar recruitment can be monitored in pig buccal mucosa microcirculation
2012
BACKGROUND Cyclic alveolar recruitment and derecruitment play a role in the pathomechanism of acute lung injury and may lead to arterial partial pressure of oxygen (PaO(2) ) oscillations within the respiratory cycle. It remains unknown, however, if these PaO(2) oscillations are transmitted to the microcirculation. The present study investigates if PaO(2) oscillations can be detected in the pig buccal mucosa microcirculation. METHODS Respiratory failure was induced by surfactant depletion in seven pigs. PaO(2) oscillations caused by cyclic recruitment and derecruitment were measured in the thoracic aorta by fast fluorescence quenching of oxygen technology. Haemoglobin oxygen saturation, haem…
Biophysics of venous return from the brain from the perspective of the pathophysiology of chronic cerebrospinal venous insufficiency
2011
This article discusses the biophysical aspects of venous outflow from the brain in healthy individuals and in patients with chronic cerebrospinal venous insufficiency. Blood flows out of the brain differently, depending on body position. In the supine position it flows out mainly through internal jugular veins, while in the upright position it uses the vertebral veins. This phenomenon is probably not due to the active regulation of the flow but instead results from the collapse of jugular veins when the head is elevated. Such a collapse is associated with a significant increase in flow resistance, which leads to redirection of the flow towards the vertebral pathway. Theoretical calculations…
The Effects of Renal Denervation on Renal Hemodynamics and Renal Vasculature in a Porcine Model
2015
Rationale Recently, the efficacy of renal denervation (RDN) has been debated. It is discussed whether RDN is able to adequately target the renal nerves. Objective We aimed to investigate how effective RDN was by means of functional hemodynamic measurements and nerve damage on histology. Methods and Results We performed hemodynamic measurements in both renal arteries of healthy pigs using a Doppler flow and pressure wire. Subsequently unilateral denervation was performed, followed by repeated bilateral hemodynamic measurements. Pigs were terminated directly after RDN or were followed for 3 weeks or 3 months after the procedure. After termination, both treated and control arteries were prepar…
Burning Mouth Syndrome
2008
ABSTRACT Background Burning mouth syndrome (BMS) is an atypical orofacial algesic syndrome. The aim of the authors' research was to investigate the morphological characteristics of peripheral blood circulation in patients with BMS in comparison with those of the peripheral blood circulation in healthy people. Methods The authors examined 28 subjects, of whom 14 (10 women and four men) had BMS and 14 (nine women and five men) were healthy control subjects. They performed videocapillaroscopic examination with a capillaroscope with a fiber-optic probe at a magnification of ×200, which allowed them to examine the morphological characteristics within the capillaroscopic area accurately. Results …
Muscarinic mobilization of choline in rat brain in vivo as shown by the cerebral arterio-venous difference of choline.
1987
In anesthetized rats, the choline levels of cerebrospinal fluid and plasma obtained from blood collected from peripheral vessels (carotid artery, cardiac vessels) and from the transverse sinus were determined with a radioenzymatic assay. Cortical release of choline was studied using the "cup technique." The plasma choline level of the peripheral blood (11.5 mumol/L) was lower than that of the sinus blood. The resulting cerebral arterio-venous difference of choline was negative (3.2 mumol/L) and reflected the net release of choline from the whole brain. The plasma choline levels were not different irrespective of whether the rats were anesthetized with ether, urethane, or pentobarbital. Howe…