Search results for " blood flow"

Quantification of intracranial contribution to rheoencephalography by a numerical model of the head

2000

Abstract Objectives : Partial contributions of intracranial and extracranial circulation to rheoencephalography (REG) remain uncertain. The main goal of this work is to determine theoretically the capability of REG techniques to reflect intracranial blood flow. Methods : Head and current injection electrodes were computationally modeled to assess REG sensitivity to brain and scalp conductivity changes. Data obtained were related to tissue perfusions to calculate the partial contribution of cerebral blood perfusion to REG I, REG II and monopolar REG and to assess their amplitudes. Results : When REG I and monopolar REG were used, the theoretical maximum of intracranial contribution was reach…

The Influence of Oxygen Affinity of Blood and Cerebral Blood Flow on Cerebral Oxygen Supply

1969

The quantity of oxygen transported, per unit of time, by the blood to the brain, is determined by the blood flow, the oxygen capacity, and the oxygen affinity of the blood. The O2-exchange between the blood and the tissue cells depends mainly on the oxygen transport characteristics of the blood and the O2 diffusion conditions in the blood and tissue.

Inflammation and impaired endothelium-dependant vasodilatation in non obese women with gestational diabetes mellitus: preliminary results

2013

International audience; BACKGROUND: To evaluate whether abnormal endothelial function, a common finding in gestational diabetes mellitus (GDM) pregnancies, can be explained by inflammatory cytokines. METHODS: Forearm skin blood flow (FSBF), into response to acetylcholine (Ach) (endothelium-dependent vasodilatation), were measured in 24 pregnant control subjects and 28 gestational diabetes mellitus (GDM) women, in the third trimester of gestation. A fasting glycemic and lipidic panel was obtained, and inflammatory cytokines (TNF-alpha and IL-6) and adiponectin were also determined. RESULTS: FSBF is significantly reduced in GDM group compared with control subjects (344.59 +/- 57.791 vs.176.38…

Ovarian size and blood flow in women with polycystic ovary syndrome (PCOS) and their correlations with some endocrine parameters

2005

Objective: To determine how common polycystic ovarian morphology may be in women given the clinical diagnosis of polycystic ovary syndrome (PCOS) based on chronic anovulation and hyperandrogenism and whether certain hormonal factors correlate with ovarian morphology and blood flow. Design: Prospective study. Setting: Two academic endocrinology centers in Italy. Patient(s): Three hundred twenty-six women with PCOS and 50 age-matched and weight-matched ovulatory women. Intervention(s): Ultrasound assessment of ovarian morphology in patients and controls and ovarian blood flow and fasting hormone levels in a subset of 50 patients and matched controls. Main Outcome Measure(s): Ovarian morpholog…

NG-monomethyl-L-arginine and NG-nitro-L-arginine inhibit endothelium-dependent relaxations in human isolated omental arteries.

1991

Abstract The L-arginine analogues NG-monomethyl-l-arginine (l-NMMA, 10−4  m) and NG-nitro-L-arginine methyl ester (l-NAME, 10−4  m), which specifically inhibit the synthesis of nitric oxide from l-arginine, significantly reduced acetylcholine-induced endothelium-dependent relaxations in rings of human omental arteries. The inhibitory potency of l-NMMA and l-NAME was similar. Addition of l-NMMA or l-NAME to the organ bath did not induce any significant changes in the resting tension of the tissues. The effects of l-NMMA were reversed by l-arginine (3 × 10−4  m). The l-NMMA enantiomer, d-NMMA (10−4  m), did not influence either the basal tone of the preparation or the relaxing effects of acet…

Spectrum of mutations in the renin-angiotensin system genes in autosomal recessive renal tubular dysgenesis

2012

Autosomal recessive renal tubular dysgenesis (RTD) is a severe disorder of renal tubular development characterized by early onset and persistent fetal anuria leading to oligohydramnios and the Potter sequence, associated with skull ossification defects. Early death occurs in most cases from anuria, pulmonary hypoplasia, and refractory arterial hypotension. The disease is linked to mutations in the genes encoding several components of the renin-angiotensin system (RAS): AGT (angiotensinogen), REN (renin), ACE (angiotensin-converting enzyme), and AGTR1 (angiotensin II receptor type 1). Here, we review the series of 54 distinct mutations identified in 48 unrelated families. Most of them are no…

Splanchnic perfusion and regional pulmonary blood flow during cardiac bypass

2001

EFSUMB Guidelines 2011: Comment on Emergent Indications and Visions

2012

The focus of this article is the emergent and potential indications of contrast-enhanced ultrasound (CEUS). Emergent applications of CEUS techniques include extravascular and intracavitary contrast-enhanced ultrasound, quantitative assessment of microvascular circulation for tumor response assessment, and tumor characterization using dynamic contrast-enhanced ultrasound (DCE-US). Potential indications for microbubble agents include novel molecular imaging and drug and gene delivery techniques, which have been successfully tested in animal models. "Comments and Illustrations of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Non-Liver Guidelines 2011" whi…

Comparison of Arterial and Venous Blood Flow Between Patients with Pressure Dressing or a New Hemostatic Puncture Closure Device After Cardiac Cathet…

1997

The aim of the study was to compare arterial and venous flow volume in the punctured leg in patients given a conventional pressure dressing and those given a new hemostatic puncture closure device (Angio-Seal) after cardiac catheterization. We prospectively measured blood flow in 25 patients with pressure dressing (group A) and 25 patients with Angio-Seal (group B) after cardiac catheterization. Duplex sonographic measurements were performed at the superficial femoral artery and vein of the punctured leg. In group A measurements were performed before catheterization, during pressure dressing, and after removal of pressure dressing. In group B we performed the measurements before catheteriza…

Myocardial blood flow quantification for evaluation of coronary artery disease by computed tomography

2017

During the last decade coronary computed tomography angiography (CTA) has become the preeminent non-invasive imaging modality to detect coronary artery disease (CAD) with high accuracy. However, CTA has a limited value in assessing the hemodynamic significance of a given stenosis due to a modest specificity and positive predictive value. In recent years, different CT techniques for detecting myocardial ischemia have emerged, such as CT-derived fractional flow reserve (FFR-CT), transluminal attenuation gradient (TAG), and myocardial CT perfusion (CTP) imaging. Myocardial CTP imaging can be performed with a single static scan during first pass of the contrast agent, with monoenergetic or dual…