Cross-sectional Area Of Blood Vessels Research Articles

Heat transfer and hemodynamic analysis of systolic and diastolic hypertension on abdominal aortic thrombosis

Thrombosis is a blood clot formed in the vascular system and obstructs blood flow by reducing the cross-sectional area of blood vessels, posing a great threat to human health. Computational hemodynamics is a well-known method used for numerical simulation of blood flow behaviour. Diastolic and systolic hypertension can be investigated using the FVM and SIMPLE scheme for pressure-velocity coupling. Thanks to the utilization of MRI and DICOM, there is an acceptable 3D geometric accuracy based on which the geometry was constructed. In this study, a numerical study was performed on the behavior of the non-Newtonian blood flow in the abdominal aorta with different shapes of thrombus in three thermal fluxes generated by the body (i.e., running, sleeping, and standing). So, Blood flow behavior in three thrombus shapes of circular, rectangular, and triangular was also explored. This paper reported the influence of dimensionless numbers, including pressure drop, heat transfer coefficient, temperature, and Average Wall Shear Stress (AWSS). Based on clinical data, velocities in the abdominal aorta range from 1 to 1.2 m s−1, and blood temperature is 309.55 K. The results showed that the triangular thrombus was the most effective.

HISTOMORPHOMETRIC PARAMETERS IN SIMULATED GINGIVAL RECESSION

This study addresses the nature of morphological changes occurring in periodontal tissues through the development of gum recession in the experiment. Gingival recession was found to occur along with a decrease in epithelial thickness of the mucous membrane as well as a decreasing cross-sectional area of blood vessels, whereas the connective tissue featured fibrinoid swelling. Initial tissue ischemia in the affected area can have a negative effect on reparation. This should be borne in mind when planning a periodontal plastic surgery.

Pathomorphological changes of the vascular bed and the state of collateral blood flow in cerebral infarction

The aim of the study. To study the pathomorphological changes of the vascular bed and the state of collateral blood flow in cerebral infarction.Materials and methods. The brains of 45 deceased patients with hemispheric infarctions with different terms of the disease were studied during the work. The comparison group consisted of 10 patients who died suddenly from acute coronary insufficiency, who did not have diseases of the nervous system.To assess the morpho-functional state of blood vessels and the intensity of blood flow the cross-sectional area of blood vessels, the area of endothelial cell nuclei, the density of their location and the length of the capillary network were determined.Results. In the early stages of stroke, along with the processes of irreversible damage of small capillaries in the area of infarction and partly in the area of the penumbra, myocardial thrombosis and constant number of vessels in the perifocal area of infarction, there are processes aimed at providing effective blood flow in ischemic areas of brain by increasing collateral blood flow from the leptomeningeal vessels, increasing the diameter of blood vessels and the length of the capillary network. On the 6th day of the disease, the processes of collagenization of the subarachnoid space are registered, which reduced the collateral blood flow from the pial vessels to the underlying cortical parts of the brain. With the increasing of the disease duration, the diameter of the capillaries returns to initial values, in the perifocal areas of the infarct there is a recalibration of the lumen of the arterioles with a decrease in the total cross-sectional area of newly formed vessels, a significant number of arterioles with obliteration of the lumen are present.Conclusions. In the early stages of ischemic stroke there is an increase in blood circulation due to an increase in the diameter of the capillaries, the length of the capillary network and increased collateral circulation by the pial vessels. In the long-term period there is a reduction in the total area of the lumen of arterioles and a decrease in the efficiency of collateral blood flow, which should be regarded as an adaptive response of the vascular bed to decreased need for blood supply to stroke areas at the stage of cyst formation.

Technique for Measuring the Internal Diameter and Area of Visible Vessels of the Eye

The study of the effects on the microvasculature of various vasoactive drugs requires appro-priate methods and equipment for determining the basic physiological parameters of small blood vessels: their internal diameter and cross-sectional area, specific density, and blood flow velocity. Therefore, the purpose of the article is to study the possibilities of improving the reliability of determining the internal diameter and cross-sectional area of the visible blood vessels of bulbar con-junctival of the eye.A technique for obtaining digital video recordings of the bulbar conjunctiva of the eye, based on the pulse illumination of the study area, is proposed. A prototype of the equipment with a spatial resolution of 2 µm video is described, which allows to trace all visible blood vessels, including capillaries. An algorithm for stabilizing the position of a sequence of digital images of the bulbar conjunctiva relative to the first frame is discussed. It is based on the use of subpixel interpolation when searching for a global minimum of the standard deviation of the differences in brightness of the first and selected frame.The proposed algorithms for tracing the vascular pattern and determining the internal diameter and cross-sectional area of the blood vessels are described. An original method for calculating them is proposed, which is based on determining the area and height of a cross section of a blood vessel image. The problem of verification of the obtained results is discussed.The described approach to make it possible to create diagnostic images of the visible blood vessels of the bulbar conjunctiva, including the capillaries, with an indication of their diameters. Examples of the construction of histograms of the distribution of the internal diameter and cross-sectional area of these blood vessels are presented.The proposed technique and hardware solutions have the prospect of being used in creating equipment for complex non-invasive diagnostics of the microvasculature and monitoring the effectiveness of treating various diseases of the cardiovascular system, since the conditions of the eye blood vessels correlate with the state of the blood vessels in other organs.

Curcumin Effect on the Prevention of Gingival Overgrowth Following Phenytoin Consumption in Rats: A Clinicohistological and Immunohistochemical Study

At the moment there is no clear evidence with clinico-histological and immunohistochemical studies in animals to show the curcumin effect on the gingival overgrowth following phenytoin consumption. The purpose of the present study was to identify this subject. In this experimental study, 50 adult male Wistar rats were divided into three groups. The rats in groups I and II received 100 mg/kg of phenytoin per day. Group II also received 20 mg/kg intraperitoneal curcumin per day. The control group received the curcumin vehicle only. Gingival clinical dimensions were measured at the beginning and end of the study. The rats were then sacrificed, biopsy of gingiva was prepared, and the samples were stained with hematoxylin-eosin. Morphometry was performed to evaluate the degree of inflammation, epithelial thickness, number, and cross-sectional area of the blood vessels. Immunohistochemical staining was performed using Ki67 and α-SMA. Compared to the control group, Phenytoin in group I increased gingival volume. There was significance difference in group II with group I and control after intervention in the clinical view (p = 0.002). The difference in the number of blood vessels between groups I and II was statistically significant (p = 0.001). Significant differences were observed in blood vessel cross-sectional area (p = 0.001), epithelial thickness (p = 0.002), Ki67, and α-SMA expression between groups I and II (p = 0.001). In rats, curcumin seems to exerts its effects in preventing an increase in gingival volume caused by Phenytoin through decreasing the inflammatory infiltration, decreasing the number of blood vessels and increasing their cross-sectional area, decreasing the thickness of the epithelium, and decreasing the expression of Ki67 and α-SMA. It is suggested that curcumin may be effective in treatment of gingival enlargement following Phenytoin consumption in future. Larger sample size and clinical trials study are recommended. How to cite this article: Eftekharian S, Seifi S, Satari FD, et al. Curcumin Effect on the Prevention of Gingival Overgrowth Following Phenytoin Consumption in Rats: A Clinicohistological and Immunohistochemical Study. J Contemp Dent Pract 2019;20(10):1146-1150.

Bidirectional juxtacrine ephrinB2/Ephs signaling promotes angiogenesis of ECs and maintains self-renewal of MSCs

Co-transplantation of endothelial cells (ECs) and mesenchymal stem cells (MSCs) is an important strategy for repairing complex and large bone defects. However, the ways in which ECs and MSCs interact remain to be fully clarified. We found that forward ephrinB2/Ephs signaling from hBMSCs to hUVECs promoted the tube formation of hUVECs by activating the PI3K/AKT/mTOR pathway. Reverse ephrinB2/Ephs signaling from hUVECs to hBMSCs promoted the proliferation and maintenance of hBMSCs self-renewal via upregulation of OCT4, SOX2, and YAP1. Subcutaneous co-transplantation of ECs and MSCs in nude mice confirmed that forward ephrinB2/Ephs signaling could increase the cross-sectional area of blood vessels in the transplanted area, and reverse ephrinB2/Ephs signaling could maintain the self-renewal of transplanted hBMSCs in vivo. Based on these results, ephrinB2/Ephs bidirectional juxtacrine regulation between ECs and MSCs plays a pivotal role in improving the healing of bone defects by promoting angiogenesis and achieving a sufficient number of MSCs.

Blood oxidative stress (BLOS) is a secondary host defense system responding normally to anaerobic wound infection and inadvertently to dietary ultra-exogenous sulfide formation (USF)

Blood oxidative stress (BLOS) is the presence of white blood cells and platelets that are generating high levels of reactive oxygen species (ROS). A mathematical model links the level of BLOS or BLOS# and plasma sulfide concentration. An increase in the BLOS# reduces the plasma sulfide concentration. The reported maximum plasma sulfide concentration for defined health conditions were used to calculate the minimum BLOS#. Elevated BLOS generates high plasma concentration of ROS, which triggers multiple responses in the body that protect the host. First, insulin production by the pancreas is inhibited, which results in elevated blood glucose levels. This results in advanced glycation end products (AGE), which thicken the blood vessel wall. Elevated blood glucose levels also increases urination, which reduces the availability of substrates for infectious bacteria. Second, one or more signaling molecules are stimulated to produce vascular hypertrophy resulting in hypertension. Third, the initial stage of atherosclerosis thickens the blood vessel wall while also protecting the inner surface of the blood vessels from localized infection. The first three mechanisms provide added protection against pathogen migration through the blood vessel wall and reduce the cross-sectional area of blood vessels, which increases the retention time (RT) for improved ROS inactivation of pathogens. Fourth, genes expressed in the liver, which are associated with drug oxidation and uptake transport, are inhibited. This inhibition protects the host from any toxins produced by an anaerobic infection. Elevated BLOS also reduces plasma sulfide concentration, which inhibits wound healing and extends aerobic conditions of the wound. The normal induction of BLOS offers a short-term, cascade of several primary mechanisms for secondary defense against anaerobic infection of a wound. Normal induction of BLOS is due to ultra-exogenous sulfide formation (USF) generated by a local anaerobic infection of a wound in the natural environment. The presence of BLOS without infection is indicative of inadvertent dietary induction. Long-term dietary BLOS results in many severe inflammatory diseases and cancers that are common in an ageing population. Glands were identified as more susceptible to cancers caused by long-term dietary BLOS. Variable BLOS levels in patients of clinical trials may also be reducing effectiveness of experimental drugs and causing drug toxicity. If BLOS is confirmed as a secondary defense against infection that is inadvertently triggered by diet, then a large number of common health problems may be treated and managed by apheresis and dietary changes.

Anticoagulation in combination with antiangiogenesis and chemotherapy for cancer patients: evidence and hypothesis.

Hypercoagulable state and disorganized angiogenesis are two conspicuous characteristics during tumor progression. There are a considerable number of clinical trials focusing on the effects of anticoagulant and antiangiogenic drugs on the survival of cancer patients. Favorable outcomes have been observed. Excessive blood coagulation not only causes cancer-associated thrombosis, which is a common complication and is the second leading cause of death in patients, but also decreases intratumoral perfusion rates and drug delivery by reducing the effective cross-sectional area of blood vessels. Meanwhile, structural and functional abnormalities of the tumor microvasculature also compromise convective drug transport and create a hypoxic and acidic microenvironment. Vascular normalization strategy can temporarily recover the abnormal state of tumor vasculature by improving blood density, dilation, and leakiness, resulting in enhanced penetration of chemotherapies and oxygen within a short time window. In this article, we first review the evidence to support the opinion that anticoagulant and antiangiogenic therapy can improve cancer survival through several underlying mechanisms. Next, we speculate on the feasibility and value of the combined strategy and discuss whether such a combination has a synergistic antineoplastic effect in cancer patients by way of increasing blood vessel perfusion and drug distribution.

Effects of stenotic severity on the flow structure in a circular channel under a pulsatile flow

Stenosis is the drastic reduction in the cross-sectional area of blood vessel caused by accumulations of cholesterol. It affects the blood flow property and structure from the fluid dynamic point of view. To understand the flow phenomenon more clearly, a particle image velocimetry method is used and the fluid dynamic characteristics in a circular channel containing stenosis structure is investigated experimentally in this study. Different stenotic-structured models made of acrylic material are subjected to a pulsatile flow generated by an in-house designed pulsatile pump. The inner diameter of the tube inlet is 20 mm and the length of reduced area for stenosis ranges between 35mm and 40mm. It is circulated continuously through a circular channel by the pump system. Pressure is measured at four different sections during systolic and diastolic phase changes. The phase-averaged velocity field distribution shows a recirculation regime after the stenotic structure. The effects of the stenotic obstructions are found to be more severe when the aspect ratio is varied.

Experimental Diabetes Induces Structural, Inflammatory and Vascular Changes of Achilles Tendons

This study aims to demonstrate how the state of chronic hyperglycemia from experimental Diabetes Mellitus can influence the homeostatic imbalance of tendons and, consequently, lead to the characteristics of tendinopathy. Twenty animals were randomly divided into two experimental groups: control group, consisting of healthy rats and diabetic group constituted by rats induced to Diabetes Mellitus I. After twenty-four days of the induction of Diabetes type I, the Achilles tendon were removed for morphological evaluation, cellularity, number and cross-sectional area of blood vessel, immunohistochemistry for Collagen type I, VEGF and NF-κB nuclear localization sequence (NLS) and nitrate and nitrite level. The Achilles tendon thickness (µm/100g) of diabetic animals was significantly increased and, similarly, an increase was observed in the density of fibrocytes and mast cells in the tendons of the diabetic group. The average number of blood vessels per field, in peritendinous tissue, was statistically higher in the diabetic group 3.39 (2.98) vessels/field when compared to the control group 0.89 (1.68) vessels/field p = 0.001 and in the intratendinous region, it was observed that blood vessels were extremely rare in the control group 0.035 (0.18) vessels/field and were often present in the tendons of the diabetic group 0.89 (0.99) vessels/field. The immunohistochemistry analysis identified higher density of type 1 collagen and increased expression of VEGF as well as increased immunostaining for NFκB p50 NLS in the nucleus in Achilles tendon of the diabetic group when compared to the control group. Higher levels of nitrite/nitrate were observed in the experimental group induced to diabetes. We conclude that experimental DM induces notable structural, inflammatory and vascular changes in the Achilles tendon which are compatible with the process of chronic tendinopathy.

협착 동맥혈관의 혈류유동 모델링

동맥경화는 혈관 안에서 콜레스테롤의 침착 때문에 혈관이 좁아지거나, 딱딱해 지거나, 두꺼워 지게 되는데, 이런 현상이 심해지게 되면 동맥은 단단해져서 혈액이 원활히 통과하지 못하게 되고 심하면 사망 까지 이르게 되는 것이다. 본 연구에서는 복대동맥에서의 동맥경화가 진행되는 것을 탄성 혈관 일 때와 강성 혈관 일 때 각각 협착률이 혈관 직경의 20과 45%로 설정하고 속도와 압력 변화를 살펴보기 위하여 유한 요소 해석을 이용하여 모델링을 하였다. 혈관이 탄성 혈관일 때 속도와 압력 값은 협착률이 혈관 직경의 20%일 때 보다 45%일 때 더 높게 나타났으며, 강성 혈관에서 속도와 압력 값은 협착률이 혈관 직경의 20%일 때보다 45%에서 더 높았다. 협착률이 혈관 직경의 20과 45%인 탄성 혈관에서 재순환영역이 나타났다. 본 연구결과 혈관 협착에 따른 혈류역학적 특징을 이해하는데 도움이 될 것으로 판단된다. 【This study is about atherosclerosis which occupies the highest rate in many diseases people have and we have studied about atherosclerosis for abdominal aorta. Atherosclerosis is the phenomenon which blood vessel gets narrower, harder and thicker due to the stenosis of colesterol in blood vessel. If it becomes worse, arteries will be hard and blood can't flow smoothly, and even it can reach to death. In this study, the geometric models of the considered stenotic blood flow are two different types of constriction of cross-sectional area of blood vessel; 20 and 45% of constriction in each elastic wall and rigid wall. We have modeled by using finite element method to observe the changes of velocity and pressure. In case of the diameter of blood vessel decreased 45% in elastic wall model, the values of velocity and pressure were higher than the case of 20% and in case of the diameter of blood vessel decreased 45% in rigid wall model, the values of velocity and pressure were higher than the case of 20%. In cases of elastic wall models of the diameters of blood vessels decreased each of 20% and 45%, recirculation zones appeared. This results show understanding of hemodynamic properties depending on stenosed blood vessels.】

Developing DCE-CT to Quantify Intra-Tumor Heterogeneity in Breast Tumors With Differing Angiogenic Phenotype

The objective of this study is to evaluate the ability of dynamic contrast enhanced computed tomography (DCE-CT) to assess intratumor physiological heterogeneity in tumors with different angiogenic phenotypes. DCE-CT imaging was performed on athymic nude mice bearing xenograft wild type (MCF-7(neo)) and VEGF-transfected (MCF-7(VEGF)) tumors by using a clinical multislice CT, and compared to skeletal muscle. Parametrical maps of tumor physiology--perfusion (F), permeability-surface area (PS), fractional intravascular plasma (f(p)), and interstitial space (f(is))--were obtained by fitting the time-dependent contrast-enhanced curves to a two-compartmental kinetic model for each voxel (0.3 x 0.3 x 0.75 mm(3)). Mean physiological measurements were compared with (positron emission tomography (PET) imaging, and the spatial distribution of tumor vasculature was compared with histology. No statistically significant difference was found in mean physiological values of F, PS, and f(p) in MCF-7(neo) and muscle, while f(is) of MCF-7(neo) was a factor of two higher ( p < 0.04). MCF-7(neo) tumors also showed a radial heterogeneity with significant higher physiological values in periphery than those in middle and core regions ( p < 0.01 for all physiological parameters). MCF-7(VEGF) tumors demonstrated significant increases in all physiological parameters compared with MCF-7(neo) tumors, and a distinct saccular heterogeneous pattern compared with MCF-7(neo) and muscle. Both PET imaging and histological results showed good correlation with the above results for this same mouse model. No statistically significant difference was found in the mean perfusion and intravascular volume measured by PET imaging and DCE-CT. Increases in cross-sectional area of blood vessels ( p < 0.002) were observed in MCF-7(VEGF) tumors than MCF-7(neo), and their spatial distribution correlated well with the spatial distribution of f(p) obtained by DCE-CT. The results of this study demonstrated the feasibility of DCE-CT in quantification of spatial heterogeneity in tumor physiology in small animal models. Monitoring variations in the tumor environment using DCE-CT offers an in vivo tool for the evaluation and optimization of new therapeutic strategies.

Ultrastructural and morphometric studies related to expression of the cell adhesion molecule PECAM-1/CD31 in developing rat lung.

It has recently been postulated that platelet/endothelial cell adhesion molecule-1 (PECAM-1/CD31) might play a role in vascular tube formation. To evaluate the role of PECAM-1/CD31 in the formation of the capillary network in vivo, we conducted an ultrastructural immunohistochemical evaluation of the localization of PECAM-1/CD31 and its developmentally regulated expression in the periphery of the lungs of fetal, newborn, and adult rats. PECAM-1/CD31 was present mainly on luminal surfaces and at the junctions between endothelial cells. Moreover, in fetal lung, products of the immunoreaction were also found on the abluminal surfaces of endothelial cells. To relate those findings to the developmental changes in the capillary area of the lung, we performed a morphometric study of electronmicrographs. The cross-sectional area of blood vessels at the periphery of the lungs was significantly greater in 15-19-day-old fetuses than in postpartum animals (p<0.0001). Disappearance of the expression of PECAM-1/CD31 on the abluminal endothelial surface paralleled the changes in the cross-sectional area of blood vessels that occurred during the perinatal period. (J Histochem Cytochem 48:1283-1289, 2000)