Search results for "microcirculation"
showing 10 items of 319 documents
A Contribution Concerning the Unsettled Problem of Intrasplenic Microcirculation
1973
From morphological studies it is well known that the vascular bed of the spleen consists of at least two different compartments. Figure one schematically shows how the splenic microcirculation can be subdivided. One compartment corresponds to the white pulp (pathways number 1 and 2), the other compartment to the red pulp, for which the existance of either an open or a closed type of terminal vascular bed is discussed. Futhermore there are references that the microcirculation in the red pulp is not homogeneous but composed of both types, as illustrated by the pathways marked by number 3 and 4.
Retinal vascular network: description in elderly and pathological process
2020
For more than 10 years, description of the retinal microvascular network has benefited from the development of new imaging techniques. Automatic retinal images analysis software, as well as OCT angiography, are able to highlight subtle and early changes in the retinal vascular network. In addition, these software allow to obtain a large amount of quantitative microvascular parameters which improve the characterization of retinal vascularization. The challenge of current research is to demonstrate the association between these microvascular modifications, systemic vascular aging process and cerebral and cardiovascular disease. Indeed, a physiopathological continuum exists between retinal mic…
Stretch-induced Intussuceptive and Sprouting Angiogenesis in the Chick Chorioallantoic Membrane
2014
Vascular systems grow and remodel in response to not only metabolic needs, but also mechanical influences as well. Here, we investigated the influence of tissue-level mechanical forces on the patterning and structure of the chick chorioallantoic membrane (CAM) microcirculation. A dipole stretch field was applied to the CAM using custom computer-controlled servomotors. The topography of the stretch field was mapped using finite element models. After 3 days of stretch, Sholl analysis of the CAM demonstrated a 7-fold increase in conducting vessel intersections within the stretch field (p 0.05). In contrast, corrosion casting and SEM of the stretch field capillary meshwork demonstrated intense …
Mutes gļotādas mikrocirkulācijas novērtējums izmantojot attēlvides fotopletizmogrāfiju
2019
Manipulācijas ar smaganām ir kļuvušas par standarta procedūrām zobārstniecībā rosinot nepieciešamību pēc smaganu funkcionālām izvērtēšanas metodēm. It īpaši tādēļ, ka smaganu klīniskā aina nevienmēr atspoguļo to funkcionālo stāvokli un morfoloģiskās īpatnības var nomaskēt funkcionālos traucējumus. Vietējā anestēzija ir neatņemama zobārstniecības procedūra, kas novērš pacienta diskomfortu manipulāciju laikā, taču dažreiz tā var radīt arī nevēlamās blakusparādības vai pat komplikācijas, kam ir vairāki iemesli (lielās devas, individuālā jutība uz kādu no anestēzijas komponentu, traucējumi pulpas un smaganu asins apgādē, vai pat neirotoksicitāte). Līdz ar to devas samazināšana ir ļoti svarīga, …
Remote photoplethysmography device with adaptive illumination for skin microcirculation assessment
2020
Measuring blood perfusion is important in medical care. However, currently available devices to measure blood perfusion are bulky, expensive and not easy-to-use. In this work a compact and portable low-cost prototype device for remote monitoring of palm skin microcirculation has been developed. Presented device consists of precisely controlled near-infrared illuminators (760nm peak wavelength) and video camera. The device with the custom designed software provides stable uniform illumination of curved skin surfaces, using feedback algorithm. Verification tests of this device showed improvements in the quality of skin blood perfusion maps in the case when the feedback system was used.
Photoplethysmography imaging algorithm for continuous monitoring of regional anesthesia
2016
An efficient photoplethy smography imaging system and advanced algorithm for continuous monitoring of skin microcirculation was developed. The system comprises compact device and computer with software for visualizing of skin blood volume changes. The software is able to process high-resolution microcirculation amplitude maps in real-time. It was tested in clinical environment during the regional anesthesia procedures. The Eulerian-based method showed improved sensitivity and higher resolution of microcirculation maps.
Intravital fluorescence microscopy for the study of leukocyte interaction with platelets and endothelial cells
1999
Publisher Summary This chapter introduces the techniques of intravital microscopy as a tool to study the microcirculation in intact animals under conditions of oxidative stress. Intravital fluorescence microscopy can be performed with almost all types of epiillumination microscopes available. The introduction of fluorescent dyes and refined epiillumination techniques has significantly advanced the possibilities of intravital microscopic studies of the liver microcirculation, including quantitative analyses of both circulatory parameters and cellular mechanisms. Using appropriate dyes, intravital microscopy allows the study of (1) microvascular perfusion, (2) leukocyte-endothelial cell inter…
Microcirculatory Dysfunction Induced by Cigarette Smoking
2000
This review deals with the deleterious effects of cigarette smoking on the microcirculation, both in terms of morphological (i.e., vessel wall injury, capillary loss) and functional aspects. The latter concerns predominantly changes in tissue perfusion and its regulatory mechanisms (i.e., reactive hyperemia, sequestration of blood cells in the microcirculation). The mechanisms of action of cigarette smoking on the microcirculation include compromised endothelial-dependent vasorelaxation, platelet aggregation, endothelial cell dysfunction, and the activation of circulating leukocytes. Through these mechanisms, cigarette smoking elicits the aggregation and adhesion of leukocytes and/or platel…
Relationship of choroidal thickness with pulsatile hemodynamics in essential hypertensive patients
2021
Controversy exists about the association of choroidal thickness (CTh) with blood pressure (BP) values. There is some evidence suggesting that central hemodynamics changes are associated with microvascular disease. Our study was aimed to assess the relationships between CTh and clinic and 24-h BP and between CTh and estimated 24-h aortic pulse pressure (aPP), 24-h aortic systolic BP (aSBP), and 24-h aortic augmentation index (aAIx) in a group of hypertensive patients. We enrolled 158 hypertensive subjects (mean age 48 ± 13 years) all of which underwent evaluation of the choroidal district by Swept-Source optical coherence tomography (SS-OCT) and 24-h BP monitoring, in order to measure periph…
Clinical evaluation of automated capillary refill time estimation in dogs and cats
2019
In this study, we clinically evaluated a pulse oximeter-based device for automated capillary refill time (CRT) estimation in dogs and cats. CRT can reveal conditions like shock or anemia in dogs and cats. However, visual CRT estimation has low repeatability, and the available optical systems for automated estimation are not suitable for pets. We evaluated a custom-made portable CRT measuring device on various measurement sites of 12 dogs and 11 cats with parallel visual CRT estimation on the gum by treating veterinarian. The capillary refill was also recorded by a video camera for reference. The visual and video procedures were moderately correlated with the coefficient of 0.61; visual CRT …