scholarly journals Hierarchical Modeling of the Liver Vascular System

2021 ◽  
Vol 12 ◽  
Author(s):  
Aimee M. Torres Rojas ◽  
Sylvie Lorente ◽  
Mathieu Hautefeuille ◽  
Aczel Sanchez-Cedillo
Keyword(s):  
Hierarchical Modeling ◽  
Vascular System ◽  
Vascular Anatomy ◽  
Circulatory System ◽  
Circulation Model ◽  
Porous System ◽  
Hepatic Diseases ◽  
Geometrical Features ◽  
Scale Range ◽  
Blood Flow Redistribution

The liver plays a key role in the metabolic homeostasis of the whole organism. To carry out its functions, it is endowed with a peculiar circulatory system, made of three main dendritic flow structures and lobules. Understanding the vascular anatomy of the liver is clinically relevant since various liver pathologies are related to vascular disorders. Here, we develop a novel liver circulation model with a deterministic architecture based on the constructal law of design over the entire scale range (from macrocirculation to microcirculation). In this framework, the liver vascular structure is a combination of superimposed tree-shaped networks and porous system, where the main geometrical features of the dendritic fluid networks and the permeability of the porous medium, are defined from the constructal viewpoint. With this model, we are able to emulate physiological scenarios and to predict changes in blood pressure and flow rates throughout the hepatic vasculature due to resection or thrombosis in certain portions of the organ, simulated as deliberate blockages in the blood supply to these sections. This work sheds light on the critical impact of the vascular network on mechanics-related processes occurring in hepatic diseases, healing and regeneration that involve blood flow redistribution and are at the core of liver resilience.

scholarly journals Studying dynamic stress effects on the behaviour of THP-1 cells by microfluidic channels

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Semra Zuhal Birol ◽  
Rana Fucucuoglu ◽  
Sertac Cadirci ◽  
Ayca Sayi-Yazgan ◽  
Levent Trabzon
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Vascular System ◽  
Circulatory System ◽  
Disease Process ◽  
Microfluidic Channels ◽  
Shear Stresses ◽  
Stress Effects ◽  
Adhesion Behavior ◽  
Cycling System

AbstractAtherosclerosis is a long-term disease process of the vascular system that is characterized by the formation of atherosclerotic plaques, which are inflammatory regions on medium and large-sized arteries. There are many factors contributing to plaque formation, such as changes in shear stress levels, rupture of endothelial cells, accumulation of lipids, and recruitment of leukocytes. Shear stress is one of the main factors that regulates the homeostasis of the circulatory system; therefore, sudden and chronic changes in shear stress may cause severe pathological conditions. In this study, microfluidic channels with cavitations were designed to mimic the shape of the atherosclerotic blood vessel, where the shear stress and pressure difference depend on design of the microchannels. Changes in the inflammatory-related molecules ICAM-1 and IL-8 were investigated in THP-1 cells in response to applied shear stresses in an continuous cycling system through microfluidic channels with periodic cavitations. ICAM-1 mRNA expression and IL-8 release were analyzed by qRT-PCR and ELISA, respectively. Additionally, the adhesion behavior of sheared THP-1 cells to endothelial cells was examined by fluorescence microscopy. The results showed that 15 Pa shear stress significantly increases expression of ICAM-1 gene and IL-8 release in THP-1 cells, whereas it decreases the adhesion between THP-1 cells and endothelial cells.

Digital motion analysis as a tool for analysing the shape and performance of the circulatory system in transparent animals

2000 ◽  
Vol 203 (11) ◽  
pp. 1659-1669 ◽  
Author(s):  
T. Schwerte ◽  
B. Pelster
Keyword(s):  
Blood Vessels ◽  
Fluorescent Probe ◽  
Motion Analysis ◽  
Vascular System ◽  
Circulatory System ◽  
Cardiac Activity ◽  
Video Frame ◽  
Peripheral Blood Flow ◽  
Gray Scale ◽  
And Performance

The analysis of perfusion parameters using the frame-to-frame technique and the observation of small blood vessels in transparent animals using video microscopy can be tedious and very difficult because of the poor contrast of the images. Injection of a fluorescent probe (fluorescein isothiocynate, FITC) bound to a high-molecular-mass dextran improved the visibility of blood vessels, but the gray-scale histogram showed blurring at the edges of the vessels. Furthermore, injection of the fluorescent probe into the ventricle of small zebrafish (Danio rerio) embryos (body mass approximately 1 mg) often resulted in reduced cardiac activity. Digital motion analysis, however, proved to be a very effective tool for analysing the shape and performance of the circulatory system in transparent animals and tissues. By subtracting the two fields of a video frame (the odd and the even frame), any movement that occurred within the 20 ms necessary for the acquisition of one field could be visualised. The length of the shifting vector generated by this subtraction, represented a direct measure of the velocity of a moving particle, i.e. an erythrocyte in the vascular system. By accumulating shifting vectors generated from several consecutive video frames, a complete trace of the routes over which erythrocytes moved could be obtained. Thus, a cast of the vascular system, except for those tiny vessels that are not entered by erythrocytes, could be obtained. Because the gray-scale value of any given pixel or any given group of pixels increased with the number of erythrocytes passing it, digital motion analysis could also be used to visualise the distribution of blood cells in transparent tissues. This method was used to describe the development of the peripheral vascular system in zebrafish larvae up to 8 days post-fertilisation. At this stage, food intake resulted in a clear redistribution of blood between muscle tissue and the gut, and alpha-adrenergic control of peripheral blood flow was established.

Modelling and Simulation Methodology for the Human Cardio Vascular System

2001 ◽  
Author(s):  
Petter Krus ◽  
Dag Teien
Keyword(s):  
Closed Loop ◽  
Vascular System ◽  
Circulatory System ◽  
Coarctation Of The Aorta ◽  
Basic Principles ◽  
Simulation Methodology ◽  
Basic Model ◽  
Valve Leakage ◽  
Human Cardiovascular System ◽  
Cardio Vascular

Abstract In this paper a methodology for closed loop simulation of the human cardiovascular system is described. It includes a functional heart model and a closed loop circulatory system. Using this model a range of physiological and patophysical phenomena can be studied, such as valvar regurgitation (valve leakage), valvar stenosis, congenital cardiac malformations i.e. coarctation of the aorta and the circulation in univentricular hearts. The model can be extended to accommodate detail descriptions of the subsystems. In this paper, however, a very basic model is shown to highlight the basic principles of cardio vascular system simulation.

Adjustments of the Circulatory System in Normal Dogs to Massive Transfusions

1956 ◽  
Vol 186 (1) ◽  
pp. 92-96 ◽  
Author(s):  
R. A. Huggins ◽  
E. L. Smith ◽  
R. A. Seibert
Keyword(s):  
Cell Volume ◽  
Plasma Volume ◽  
Vascular System ◽  
Circulatory System ◽  
Red Cell ◽  
Group V ◽  
Red Cell Volume ◽  
Group Iii ◽  
Group I ◽  
Transfusion Volume

On the basis of the amount of blood transfused in cubic centimeters per kilogram the dogs were arranged into five groups: group I, 0.0–49.0 cc/kg, group II, 50.0–99.0 cc/kg, group III, 100.0–149.0 cc/kg, group IV, 150.0– 199.0 cc/kg and group V, 200.0–249.0 cc/kg. The determinations made in each group were plasma volume, plasma proteins, hematocrit and hemoglobin. Plasma including protein escaped rapidly from the vascular system even with the smallest transfusion and in the last two groups the plasma lost exceeded that infused. Thus, any method of determining blood volume based on measurement of plasma volume must be in error. The loss of plasma protein became progressively greater as the amount of transfusion increased. The apparent increase in measured red cell volume over the expected in groups I, II and III was probably the result of loss of dye from the circulation, giving an overestimate of plasma and red cell volume. There was no evidence that cells leave the circulation until the transfusion volume became very large ( groups IV, V) and hemorrhage supervened.

Computational Study on the Effects of Peripheral Vessel Network on Blood Flow in the Arterial Circle of Willis

2007 ◽  
Author(s):  
Shigefumi Tokuda ◽  
Takeshi Unemura ◽  
Marie Oshima
Keyword(s):  
Numerical Simulation ◽  
Blood Flow ◽  
Boundary Conditions ◽  
Vascular System ◽  
Computational Study ◽  
Circulatory System ◽  
Biological Data ◽  
Patient Specific ◽  
Peripheral Vessel

Cerebrovascular disorder such as subarachnoid hemorrhage (SAH) is 3rd position of the cause of death in Japan [1]. Its initiation and growth are reported to depend on hemodynamic factors, particularly on wall shear stress or blood pressure induced by blood flow. In order to investigate the information on the hemodynamic quantities in the cerebral vascular system, the authors have been developing a computational tool using patient-specific modeling and numerical simulation [2]. In order to achieve an in vivo simulation of living organisms, it is important to apply appropriate physiological conditions such as physical properties, models, and boundary conditions. Generally, the numerical simulation using a patient-specific model is conducted for a localized region near the research target. Although the analysis region is only a part of the circulatory system, the simulation has to include the effects from the entire circulatory system. Many studies have carried out to derive the boundary conditions to model in vivo environment [3–5]. However, it is not easy to obtain the biological data of cerebral arteries due to head capsule.

scholarly journals The effect of lumen conditions on oxygen uptake in perfused omasal laminae

1985 ◽  
Vol 53 (2) ◽  
pp. 311-322 ◽  
Author(s):  
F. J. Lozeman ◽  
L. P. Milligan
Keyword(s):  
Vascular System ◽  
Vascular Anatomy ◽  
Dry Weight ◽  
Nitrogen Gas ◽  
Heat Stable ◽  
Discrete Area ◽  
Sequential Addition ◽  
Micro Organisms ◽  
Anaerobic Environment

1. The vascular anatomy of the bovine omasal lamina permitted perfusion of a discrete area of the tissue. As occurs in vivo, oxygen was provided through the vascular system, while the luminal sides of the tissue could be kept in an anaerobic environment, thus allowing study of foregut tissue metabolism under physiologically realistic conditions.2. O2consumption of perfused leaves in the presence of anaerobic buffer was 64.9 and 73.5 nmol O2/mg dry weight per h in Expts 1 and 2 respectively, and was elevated (P< 0.05) when the lumen side of the tissue was exposed to an atmosphere of nitrogen gas.3. In Expt 1, the rate of O2consumption was increased (P< 0.01) by 35% as a result of suspension of a boiled preparation of rumen micro-organisms and particles (< 1 mm) in the anaerobic lumen buffer. Replacement of the boiled preparation with an unboiled suspension increased O2consumption further by 11 %, but this was not statistically significant (P> 0.05).4. In Expt 2, sequential addition of the following substrates or preparations to the lumen chambers all resulted in stepwise increases (P< 0.05) in O2consumption; 8 mM-butyrate, boiled rumen micro-organisms and particles and, finally, unboiled rumen micro-organisms and particles.5. Identities of the heat-labile and heat-stable components of the microbial and particle suspensions that caused enhancement of O2removal across the perfused tissue are discussed.

scholarly journals Micromorphology and anatomy of the flower of Zephyranthes candida (Amaryllidaceae)

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
O. S. Fishchuk
Keyword(s):  
Vascular System ◽  
Vascular Anatomy ◽  
Vascular Bundles ◽  
Cross Sectional ◽  
Septal Nectary ◽  
Microscopic Studies ◽  
Flower Stage ◽  
Zephyranthes Candida ◽  
Significant Addition ◽  
Pollination Methods

The use of morphological features of flowers in the taxonomy of plants is becoming increasingly important. The structure of the Zephyranthes candida (Lindl.) Herb. flowers on permanent cross-sectional and longitudinal sections was studied using a light microscope. The genus Zephyranthes belongs to the subtribe Hippeastrinae Walp. tribe Hippeastreae Sweet., family Amaryllidaceae s.l. Microscopic studies of the flower are considered as a tool to identify hitherto unknown structural adaptations of plants to specialized pollination methods and to elucidate the first stages of fruit morphogenesis, as many features of the fruit appear at the flower stage. The morphometric parameters, morphology, anatomy, and vascular anatomy of the ovary were described by using the flower’s transverse sections. Ten flowers of Z. candida were sectioned using standard methods of Paraplast embedding and serial sectioning at 20 μm thickness. Sections were stained with Safranin and Astra Blau and mounted in Eukitt. It was found that in the studied species the tepals have multi-bundle traces of 10–12 leading bundles. We consider the gynoecium of the studied species to be eusincarpous. The vascular system of the inferior ovary consists of three dorsal and three septal bundles, paired ventral bundles of carpels, which form ovule traces. For the first time, the presence of the following gynoecium zones was detected: a synascidiate structural zone with a height of about 360 μm and a fertile symplicate structural zone with a height of about 1560 μm and a hemisymplicate zone of 480 μm. Septal nectaries appear in the hemisymplicate zone and open with nectary split at the base of the style, the total height of the septal nectary is 760 μm. The ovary roof is 280 μm. Bifurcated dorsal and septal bundles of carpels have been identified, which can be considered as adaptations of the early stages of fruit morphogenesis to opening. Anatomical features of the ovary of Z. candida are numerous vascular bundles in the pericarpium, non-lignified endocarp at the flower stage, we consider as adaptations to the formation of juicy fruit. New data on the anatomical structure of the flower are a significant addition to the information on antecological and post-anthetic features of the studied species. Also, these data can be used in the construction of parsimony branches of the family Amaryllidaceae.

Bifurcation Patterns and Branching Exponents in Branchial Vessels in Tadpoles of Xenopus laevis Daudin during Metamorphosis-3D-Measurements from Microvascular Corrosion Casts

2001 ◽  
Vol 7 (S2) ◽  
pp. 1188-1189
Author(s):  
B. Minnich ◽  
H. Bartel ◽  
R. Karch ◽  
W. Schreiner ◽  
A. Lametschwandtner
Keyword(s):  
Fluid Transport ◽  
Vascular System ◽  
Three Dimensional ◽  
Circulatory System ◽  
Transport Systems ◽  
Corrosion Casts ◽  
Parent Vessel ◽  
Tubular System ◽  
Anuran Tadpole ◽  
Existing Data

IntroductionFluid transport systems of organisms [1] in general and the blood vascular system in particular are considered to be optimally designed. From Murray's laws [2] it is concluded that an arterial bifurcation where the diameter of the parent vessel (d0) relates to the larger (d1) and the smaller daughter vessel (d2) according to d03 = d13 + d23 is optimal. Interestingly, existing data predominantly refer to arterial branchings of the fully developed circulatory system of mammals. to the best of our knowledge there are no data available on arterial bifurcations and venous mergings in an initially growing but then regressing tubular system of blood vessels as it is found in the gill filter apparatus of the anuran tadpole where the highly complex three-dimensional vascular network totally disappears at the end of metamorphosis.

The primo vascular system is the substance of meridians.

2020 ◽  
Author(s):  
Yongchol Cha ◽  
Hyok Choe ◽  
Songjin Oh ◽  
Zinhwa Cha
Keyword(s):  
Nephrotic Syndrome ◽  
Drug Use ◽  
Vascular System ◽  
Light Stimulus ◽  
Circulatory System ◽  
Internal Target ◽  
Pulse Light ◽  
Acupuncture Meridian ◽  
Thermal Line ◽  
Valuation Criteria

Abstract Background; The primo vascular system (PVS) is new circulatory system. However, the primo vascular system doesn’t achieve now on the valuation criteria on the substance of meridians, so that anyone can't prove that the primo vascular system is the substance of meridians. Objectives: The purpose of this study is to prove clinical-physiologically that the primo vascular system is the substance of acupuncture meridian.Methods: Meridian-like high thermal line (MLHTL) induced by the mineral pulse light stimulus on acupoints, and nephrotic syndrome treated simultaneously without any drug use, were researched and analyzed. Next, the inducing characteristic of meridian-like high thermal lines and, anatomic and electro-physiologic characteristic of PVS were researched and analyzed. Results: The KI, SP meridian-like high thermal line coinciding completely along the classic KI, SP meridian course, were induced by the mineral pulse light stimulus on SP6 acupoints, and simultaneously nephrotic syndrome in kidney, the internal target organ connected along KI meridian from the KI3, SP6 acupoints, was treated without any drug use. And the primo vascular system was basis tissue of MLHTL inducing. Conclusions: The primo vascular system was achieved completely to the valuation criteria on the substance of meridians. Thus, the primo vascular system is the substance of meridians.

Studies in the Alismataceae. III. Floral anatomy of Ranalisma humile

1973 ◽  
Vol 51 (5) ◽  
pp. 891-897 ◽  
Author(s):  
W. A. Charlton ◽  
A. Ahmed
Keyword(s):  
Vascular System ◽  
Floral Anatomy ◽  
Vascular Anatomy ◽  
Vascular Supply ◽  
Variable Amount ◽  
Peripheral Vascular ◽  
Two Systems ◽  
A Minor ◽  
Relationship Of ◽  
The Relationship

The flower of Ranalisma humile is comparable in morphology to those of other alismads. The vascular anatomy is noteworthy. Flowers of R. humile are provided with a major (central) vascular system supplying androecial and gynoecial vasculature and a variable amount of the sepal and petal vasculature, and a minor (peripheral) system which supplies the rest of the perianth vasculature. There is very little anastomosis between the two systems. It is suggested that the variability of perianth vascular supply reflects variability in timing of differentiation events. The occurrence of an almost independent peripheral vascular system is probably of significance in a consideration of the relationship of Ranalisma humile to other alismads.

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