Read by QxMD icon Read

blood flow distribution

Mesude Ozturk, Dimitrios V Papavassiliou, Edgar A O'Rear
In this work, contributing factors for red blood cell damage in turbulence were investigated by simulating jet flow experiments. Results showed that dissipative eddies comparable or smaller in size to the red blood cells cause hemolysis and that hemolysis corresponds to the number and the surface area of eddies that are associated with Kolmogorov length scale smaller than about 10 µm. The size distribution of Kolmogorov scale eddies was used to define a turbulent flow extensive property with eddies serving as a means to assess the turbulence effectiveness in damaging cells, and a new hemolysis model was proposed...
October 19, 2016: Journal of Biomechanical Engineering
Junko Nio-Kobayashi, Kaya Miyazaki, Kazuhisa Hashiba, Kiyoshi Okuda, Toshihiko Iwanaga
BACKGROUND: The mechanisms regulating the function and regression of the corpus luteum (CL) have not yet been elucidated in detail. The regressed CL of cows was previously reported to be filled with unusual vessels like arteriovenous anastomosis (AVA); however how these vessels are being established during luteolysis remains unknown. METHODS: The bovine CL at different luteal stages and regressing bovine CL induced by prostaglandin F2α (PGF) were histologically analyzed using light and electron microscopic levels...
October 19, 2016: Journal of Ovarian Research
Enrico Agabiti Rosei
Current Hypertension Guidelines emphasize the importance of assessing the presence of preclinical organ damage. In fact, an extensive evaluation of organ damage may increase the number of patients classified at high CV risk and therefore strongly influence the clinical management of patients. Hypertensive heart disease remains to date the form of organ damage for which there is the greatest amount of evidence of a strong independent prognostic significance. In the presence of a chronic pressure overload, a parallel addition of sarcomers takes place with an increase in myocyte width, which in turn increases left ventricular wall thickness; myocyte hypertrophy is also associated with apoptosis, collagen deposition and ventricular fibrosis with an impairment of coronary hemodynamics as well, thus profoundly influencing functional properties of the left (and right) ventricle...
September 2016: Journal of Hypertension
Alberto Avolio
Blood vessels function as conduits for distribution of blood throughout the circulatory system. Large arteries, in addition to the essential conduit function, also serve to dampen the effect of pulsatile ventricular ejection that generates pulsatile pressure with each cardiac cycle; that is, they exhibit a 'cushion' function. The conduit function can be compromised by intimal effects that cause obstruction to flow, generally attributed to plaque formation due to intimal changes affected by atherosclerotic processes...
September 2016: Journal of Hypertension
Junichiro Hashimoto
The central aorta constitutes the main trunk of the systemic arterial tree. It dilates passively with cardiac ejection during systole and then constricts with its recoil function during diastole, thereby regulating blood pressure and blood flow. The central pulsatile hemodynamics affects local hemodynamics within as well as downstream of the aorta (e.g., end organs).The aorta progressively stiffens and dilates with advancing age, and such age-dependent change is accelerated by hypertension. According to the law of Laplace, wall stress depends on the diameter and pressure of the blood vessel...
September 2016: Journal of Hypertension
Jorge Aramburu, Raúl Antón, Alejandro Rivas, Juan Carlos Ramos, Bruno Sangro, José Ignacio Bilbao
Radioembolization, which consist of the implantation of radioactive microspheres via intra-arterially placed microcatheter, is a safe and effective treatment for liver cancer. Nevertheless, radioembolization-related complications and side effects may arise, which are an active area of ongoing research. The catheter design has been claimed as an option in reducing these complications. In this paper, the influence of catheter type and location are investigated. The study was undertaken by numerically simulating the particle-hemodynamics in a patient-specific hepatic artery during liver radioembolization...
October 7, 2016: Journal of Biomechanics
Ramona Sturm, David Heftrig, Katharina Mörs, Nils Wagner, Kerstin Kontradowitz, Katrin Jurida, Ingo Marzi, Borna Relja
OBJECTIVE: Phagocytizing leukocytes (granulocytes and monocytes) play a fundamental role in immunological defense against pathogens and clearance of cellular debris after tissue injury due to trauma. According to the "two-hit hypothesis", phagocytes become primed due to/after trauma. Subsequently, a secondary stimulus may lead to their exaggerated response. This immune dysfunction can result in serious infectious complications, also depending on trauma injury pattern. Here, we investigated the phagocytizing capacity of leukocytes, and its correlation to trauma injury pattern...
September 29, 2016: Immunobiology
Nicole S Glaser, Sandra L Wootton-Gorges, Isaac Kim, Daniel J Tancredi, James P Marcin, Andrew Muir, Nathan Kuppermann
OBJECTIVE: To characterize regional differences in brain water distribution and content during diabetic ketoacidosis (DKA) in children and determine whether these differences correlate with regional vascular supply. STUDY DESIGN: We compared changes in brain water distribution and water content in different brain regions during DKA by analyzing magnetic resonance diffusion weighted imaging data collected during DKA and after recovery in 45 children (<18 years of age)...
October 13, 2016: Journal of Pediatrics
Fuyou Liang, Xiaosheng Liu, Ryuhei Yamaguchi, Hao Liu
Recent studies raised increasing concern about the reliability of computer models in reproducing in vivo hemodynamics in cerebral aneurysms. Boundary condition problem is among the most frequently addressed issues since three-dimensional (3-D) modeling is usually restricted to local arterial segments. The present study focused on aneurysms on the anterior communicating artery (ACoA) which represent a large subgroup of detected cerebral aneurysms and, in particular, have a relatively high risk of rupture compared to aneurysms located in other regions...
October 6, 2016: Journal of Biomechanics
Shunichi Suzuki, Eduardo Enrique Castrillon-Watanabe, Taro Arima, Yoshimasa Kitagawa, Peter Svensson
BACKGROUND: Myofascial pain associated with temporomandibular disorders has often been linked to pathological muscle hyperactivity. As a result, localized disturbances of intramuscular blood flow could lead to a lower level of oxygen distribution, hypoxia and microcirculatory changes. AIM: To assess hemodynamic changes in the masseter muscle during sustained elevated muscle activity (SEMA). MATERIALS AND METHODS: Sixteen healthy participants performed thirty 1-minute bouts of SEMA with intervals of 1-minute "rest" periods between the bouts on a bite force transducer device...
October 15, 2016: Journal of Oral Rehabilitation
Pedram Hanafizadeh, Nima Mirkhani, Mohammad Reza Davoudi, Mahtab Masouminia, Keyvan Sadeghy
Coronary arteries, which are branched from the sinuses, have tangible effects on the hemodynamic performance of the bileaflet mechanical heart valve (BMHV), especially in the diastolic phase. To better understand this issue, a computer model of ascending aorta including realistic sinus shapes and coronary arteries has been generated in this study in order to investigate the BMHV performance during diastole. Three-dimensional transient numerical analysis is conducted to simulate the diastolic blood flow through the hinges and in coronary arteries under the assumption of non-Newtonian behavior...
October 2016: Artificial Organs
Michael Welter, Heiko Rieger
Tumor vasculature, the blood vessel network supplying a growing tumor with nutrients such as oxygen or glucose, is in many respects different from the hierarchically organized arterio-venous blood vessel network in normal tissues. Angiogenesis (the formation of new blood vessels), vessel cooption (the integration of existing blood vessels into the tumor vasculature), and vessel regression remodel the healthy vascular network into a tumor-specific vasculature. Integrative models, based on detailed experimental data and physical laws, implement, in silico, the complex interplay of molecular pathways, cell proliferation, migration, and death, tissue microenvironment, mechanical and hydrodynamic forces, and the fine structure of the host tissue vasculature...
2016: Advances in Experimental Medicine and Biology
Jongseong Kim, Jung E Park, Matthias Nahrendorf, Dong-Eog Kim
There is an emergent need for imaging methods to better triage patients with acute stroke for tissue-plasminogen activator (tPA)-mediated thrombolysis or endovascular clot retrieval by directly visualizing the size and distribution of cerebral thromboemboli. Currently, magnetic resonance (MR) or computed tomography (CT) angiography visualizes the obstruction of blood flow within the vessel lumen rather than the thrombus itself. The present visualization method, which relies on observation of the dense artery sign (the appearance of cerebral thrombi on a non-enhanced CT), suffers from low sensitivity...
September 2016: Journal of Stroke
Henrik B W Larsson, Mark B Vestergaard, Ulrich Lindberg, Helle K Iversen, Stig P Cramer
PURPOSE: Capillary transit time heterogeneity, measured as CTH, may set the upper limit for extraction of substances in brain tissue, e.g., oxygen. The purpose of this study was to investigate the feasibility of dynamic contrast-enhanced T1 weighted MRI (DCE-MRI) at 3 Tesla (T), in estimating CTH based on a gamma-variate model of the capillary transit time distribution. In addition, we wanted to investigate if a subtle increase of the blood-brain barrier permeability can be incorporated into the model, still allowing estimation of CTH...
October 12, 2016: Journal of Magnetic Resonance Imaging: JMRI
Taylor Wand, Mike Fang, Christina Chen, Nathan Hardy, J Philip McCoy, Bogdan Dumitriu, Neal S Young, Angélique Biancotto
Abnormal telomere lengths have been linked to cancer and other hematologic disorders. Determination of mean telomere content (MTC) is traditionally performed by Southern blotting and densitometry, giving a mean telomere restriction fragment (TRF) value for the total cell population studied. Here, we compared a quantitative Polymerase Chain Reaction approach (qPCR) and a flow cytometric approach, fluorescence in situ hybridization (Flow-FISH), to evaluate telomere content distribution in total patient peripheral blood mononuclear cells or specific cell populations...
October 2016: Cytometry. Part A: the Journal of the International Society for Analytical Cytology
Viviana Clavería, Othmane Aouane, Marine Thiébaud, Manouk Abkarian, Gwennou Coupier, Chaouqi Misbah, Thomas John, Christian Wagner
We present experiments on RBCs that flow through micro-capillaries under physiological conditions. The strong flow-shape coupling of these deformable objects leads to a rich variety of cluster formation. We show that the RBC clusters form as a subtle imbrication between hydrodynamic interactions and adhesion forces because of plasma proteins, mimicked by the polymer dextran. Clusters form along the capillaries and macromolecule-induced adhesion contributes to their stability. However, at high yet physiological flow velocities, shear stresses overcome part of the adhesion forces, and cluster stabilization due to hydrodynamics becomes stronger...
October 4, 2016: Soft Matter
Saba Parween, Elena Kostromina, Christoffer Nord, Maria Eriksson, Per Lindström, Ulf Ahlgren
The leptin deficient ob/ob mouse is a widely used model for studies on initial aspects of metabolic disturbances leading to type 2 diabetes, including insulin resistance and obesity. Although it is generally accepted that ob/ob mice display a dramatic increase in β-cell mass to compensate for increased insulin demand, the spatial and quantitative dynamics of β-cell mass distribution in this model has not been assessed by modern optical 3D imaging techniques. We applied optical projection tomography and ultramicroscopy imaging to extract information about individual islet β-cell volumes throughout the volume of ob/ob pancreas between 4 and 52 weeks of age...
October 7, 2016: Scientific Reports
Genevieve J Yang, John D Murray, Matthew Glasser, Godfrey D Pearlson, John H Krystal, Charlie Schleifer, Grega Repovs, Alan Anticevic
Schizophrenia (SCZ) is a disabling neuropsychiatric disease associated with disruptions across distributed neural systems. Resting-state functional magnetic resonance imaging has identified extensive abnormalities in the blood-oxygen level-dependent signal in SCZ patients, including alterations in the average signal over the brain-i.e. the "global" signal (GS). It remains unknown, however, if these "global" alterations occur pervasively or follow a spatially preferential pattern. This study presents the first network-by-network quantification of GS topography in healthy subjects and SCZ patients...
October 4, 2016: Cerebral Cortex
Xiangting Qiu, Xinhua Wang, Yucui Song, Lingling Chen
BACKGROUND: Hepatocellular carcinoma is a major type of liver cancer with poor prognosis. AIM: The aim of the study was to determine the prognostic significance of plasma interleukin-35 level in hepatocellular carcinoma. METHODS: A total of 153 hepatocellular carcinoma patients and 153 healthy controls were enrolled. Blood samples were obtained at admission. Plasma interleukin-35 level was analyzed by enzyme-linked immunosorbent assay. Distribution of T cell subset and expression of Fas/FasL protein were detected by flow cytometry...
October 3, 2016: Digestive Diseases and Sciences
M O Khan, D A Steinman, K Valen-Sendstad
Computational fluid dynamics (CFD) shows promise for informing treatment planning and rupture risk assessment for intracranial aneurysms. Much attention has been paid to the impact on predicted hemodynamics of various modelling assumptions and uncertainties, including the need for modelling the non-Newtonian, shear-thinning rheology of blood, with equivocal results. Our study clarifies this issue by contextualizing the impact of rheology model against the recently-demonstrated impact of CFD solution strategy on the prediction of aneurysm flow instabilities...
October 1, 2016: International Journal for Numerical Methods in Biomedical Engineering
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"