Search results for " circulation"

Coronary microvascular dysfunction in patients with diabetes, hypertension and metabolic syndrome

2015

Variations in acoustical beam properties of intracoronary Doppler catheters.

1993

The limitations of coronary angiography in assessing the functional significance of coronary obstructions is well known. While the critical variable of coronary blood flow cannot be readily measured, intraluminal Doppler sonography offers useful related functional information on blood flow velocity. In order to fully evaluate Doppler signals it is essential to have exact knowledge of the transducer transmission characteristics and of the ultrasound beam topology. In an experimental set-up, the transmitter-receiver characteristics of five commonly used Doppler catheters were investigated. In comparing the beam characteristics we found inhomogeneities in the lateral beam spread. At a penetrat…

Fetal programming and its effects on vascular pulmonary circulation

2018

Into the scientific community, consensus about the emerging concept of “the fetal origin of adult diseases” is growing. It sustains that the parental (of the two parents) adversities, and the related external influences, during the intra-utero/ perinatal life of each eutherian mammal organism, human included, can permanently set the structure and functionality of specific body systems (i.e., immune, endocrine, nervous and cardiovascular systems), predisposing them to early ageing and disease during adulthood. The pulmonary circulation system also appears to be one of its targets. Established evidence supports the strong association between developmental programming and pulmonary arterial re…

Effects of endothelin-1 on the cerebrovascular bed of the goat.

1991

Abstract The aim of the present study was to analyze the effects of endothelin-1 (ET-1) in the cerebrovascular bed of the goat, the importance of endothelial integrity and the contribution of extracellular Ca2+ to these responses. We measured isometric tension and 45Ca2+ uptake in isolated middle cerebral arteries, and cerebral blood flow (CBF) in unanesthetized animals. ET-1 elicited concentration-dependent contractions which were potentiated in arteries without endothelium. Ca2+-free medium and nicardipine inhibited, and Bay K 8644 potentiated the ET-1-induced contractions. ET-1 enhanced 45Ca2+ uptake in isolated arteries. Injections of ET-1 directly into the cerebral circulation decrease…

Paradoxical attenuation of leukocyte rolling in response to ischemia- reperfusion and extracorporeal blood circulation in inflamed tissue.

2005

In contrast to acute preparations such as the exteriorized mesentery or the cremaster muscle, chronically instrumented chamber models allow one to study the microcirculation under “physiological” conditions, i.e., in the absence of trauma-induced leukocyte rolling along the venular endothelium. To underscore the importance of studying the naive microcirculation, we implanted titanium dorsal skinfold chambers in hamsters and used intravital fluorescence microscopy to study venular leukocyte rolling in response to ischemia-reperfusion injury or extracorporeal blood circulation. The experiments were performed in chambers that fulfilled all well-established criteria for a physiological microcir…

Very Early Presentation of Extrahepatic Portal Vein Obstruction Causing Portal Hypertension in an Infant: Uncertainties in the Management and Therape…

2016

Extrahepatic portal vein obstruction, although rare in children, is a significant cause of portal hypertension (PHT) leading to life-threatening gastrointestinal bleeding in the pediatric age group. PHT may also lead to other complications such as hyperesplenism, cholangyopathy, ascites, and even hepatopulmonary syndrome and portopulmonary hypertension that may require organ transplantation. Herein we report the case of an asymptomatic 11-month-old infant wherein a hepatomegaly and cavernous transformation of the portal vein was detected by liver ultrasound. Neither signs of thrombosis in arteriovenous system, nor affectation of biliary tract were identified in the magnetic resonance imagin…

Quantification of myocardial blood flow and blood flow reserve in the presence of arterial dispersion: A simulation study

2002

Myocardial blood flow (MBF) can be quantified using dynamic T1-weighted MRI of diffusible tracers and a mathematical model of underlying vasculature. Quantification of MBF by means of T1- weighted MRI requires knowledge of the arterial input function (AIF). The AIF can be estimated from the left ventricular (LV) cavity. However, dispersion may occur between the LV and the tissue of interest because of the laminar blood flow profiles, branching of venules, and because of stenosis. To evaluate the influence of dispersion on the results of MBF quantification, a simulation study was performed. The dispersion was described as a convolution of the AIF with an exponential residue function. Synthet…

Endoscopic ultrasonography and portal hypertension: where are we in 2009?

2009

Endoscopic ultrasonography is currently a sensitive diagnostic and therapeutic tool with established indications, but its role in the management of portal hypertension is not well defined. This article briefly reviews indications, technologic improvements, diagnostic and interventional applications of endoscopic ultrasonography in portal hypertension.

Peripheral Changes in Blood Circulation during Autogenic Training and Hypnosis (Results of Experimental Research)

1969

In addition to the immobilization of the limbs and the associated sensation of heaviness, most patients in a hypnotic trance also experience a sensation of warmth. This subjective feeling is probably accompanied by increased skin temperature. Attempts have been made in the past to record skin temperature objectively. Most methods of measurement, however, are so defective that they have only rarely proved at all reliable. Hensel (1955, 1964) and his colleagues have described seven variables whose range is so great that the statistical evaluation of such measurements becomes impossible, even though the data may be valid in individual cases. Furthermore, graphic recording is also impracticable…

The Presence of Gestational Diabetes is Associated with Increased Detection of Anti-HLA-class II Antibodies in the Maternal Circulation

2006

Problem Gestational diabetes (GD) may be associated with temporarily reduced immune tolerance toward alloantigens for the time of pregnancy. The aim of this study was to assess anti-HLA-class I and -II antibodies as markers for an aberrant immunostimulation in women with GD. Method of study The percentage of anti-HLA-class I and -II antibodies was estimated in women with GD, normal term delivery and fetal distress, which was confirmed by demonstrating low cord blood pH for this patient group. These antibodies may cross the placental barrier and cause interleukin-6 (IL-6) release from fetal monocytes by cross-linking monocytes with antibody-loaded cells. Therefore we estimated the percentage…