The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Radu V. Stan - One of the best experts on this subject based on the ideXlab platform.
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In Vitro Vascular Cell Culture Systems – Endothelial Cell Culture Systems
Comprehensive Toxicology, 2010Co-Authors: Radu V. StanAbstract:Vascular endothelium is a highly differentiated cellular monolayer with the organization of a Simple Squamous Epithelium. It lines the entire cardiovascular system and thus constitutes a quasi-ubiquitous presence in organs and tissues throughout the body. Endothelium is a critical participant in several processes such as vascular permeability, coagulation and anticoagulation cascades, regulation of vascular tone, immune response, and formation of new vessels by vasculogenesis and angiogenesis. By its central location in tissue and organismal homeostasis, endothelium is involved in major diseases, which produced the need for the study of this cellular type in culture. In this chapter we first discuss the concept of endothelial heterogeneity and the efforts to arrive at a definition of the ECs that encompasses all endothelia. The most up-to-date methods of isolating endothelium from different sources and varied methods to culture endothelia are next presented with a stress on methods used to study angiogenesis and mechanotransduction.
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Endocytosis pathways in endothelium: how many?
American journal of physiology. Lung cellular and molecular physiology, 2006Co-Authors: Radu V. StanAbstract:vascular endothelium is a cellular monolayer with the organization of a Simple Squamous Epithelium that lines the entire cardiovascular system and constitutes a regulatable barrier between blood and tissues ([9][1], [17][2]). By its location, it is easily accessible to blood-borne drugs or imaging
Bert Binas - One of the best experts on this subject based on the ideXlab platform.
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Basal-type lumenogenesis in extraembryonic endoderm stem cells models the early visceral endoderm.
Journal of cell science, 2019Co-Authors: Minjae Kim, Yixiang Zhong, Kyoung Hwa Jung, Young Gyu Chai, Bert BinasAbstract:ABSTRACT Cultured rat primitive extraembryonic endoderm (pXEN) cells easily form free-floating multicellular vesicles de novo, exemplifying a poorly studied type of morphogenesis. Here, we reveal the underlying mechanism and the identity of the vesicles. We resolve the morphogenesis into vacuolization, vesiculation and maturation, and define the molecular characteristics and requirements of each step. Vacuolization is fueled by macropinocytosis and occurs by default if not blocked by high cell density or matrix proteins. Fine-tuned cell–cell contact then forms nascent three-cell vesicles with vacuole-derived lumina. In maturation, the vesicles complete epithelialization, expand via mitosis and continued fluid uptake, and differentiate further. The mature vesicles consist of a Simple Squamous Epithelium with an apical-outside/basal-inside polarity that we trace back to the single cell stage. The polarity and gene expression pattern of the vesicles are similar to those of the early visceral endoderm. pXEN cells provide a useful in vitro model for study of matrix-independent, basal-type lumenogenesis and the physiology of the visceral endoderm. This article has an associated First Person interview with the first author of the paper.
Wael Ghonimi - One of the best experts on this subject based on the ideXlab platform.
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Moderator Bands (Trabecula septomarginalis) of Mature Buffalo (Bosbubalis L.) with Special Emphasis on the Structure and Distribution of thePurkinje Cardiomyocytes: Histological and Histochemical
Cell & Developmental Biology, 2015Co-Authors: Wael GhonimiAbstract:Ten hearts of mature healthy Buffalo (Bos bubalis L.) were employed to investigate the histological and histochemical structures of the moderator bands. Hearts were gently dissected and the moderator bands were collected. The specimens were processed histologically and subjected to different stains. Grossly, the moderator band (Septomarginal trabeculae) was a single muscular band that was found only in the right ventricle of the buffalo heart. It extended from the interventricular septum to the free ventricular wall especially at the base of the papillary muscle, crossing and passing through the ventricular cavity. Histologically, the moderator band was invested in a dense capsule of connective tissue, endocardium that is mainly consisting of three layers; the endothelial layer of Simple Squamous Epithelium, subendothelial layer of loose connective tissue and the subendocardial layer that connects the endocardium with myocardium. Internally, about 4/5 of the core, myocardium is of the cardiac muscle fibers that arranged in bundles of one direction while only about 1/5 is lodged by purkinje cardiomyocytes that were arranged in bundles distributing mainly in two areas within the moderator band; the subendocardial layer beneath the subendothelial connective tissue and myocardium in between the cardiac myocytes bundles. Centrally, a medium-sized artery of thick wall and a very distinct internal elastic lamina was observed running at the center of the band myocardium and is surrounded with the cardiac myocytes bundles.
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gross and microanatomical studies on the moderator bands septomarginal trabecula in the heart of mature dromedary camel camelus dromedarius
Journal of Advanced Veterinary and Animal Research, 2014Co-Authors: Wael Ghonimi, Ahmad Awad Abuelatta, Mohamed Hafez Bareedy, Ahmad BalahAbstract:The current work was carried out to investigate the gross and microanatomical features of moderator bands (septomarginal trabecula) in camel heart. Ten hearts were collected from healthy mature dromedary camels. Anatomically, the moderator bands were present in both right and left ventricles. In right ventricle, the walls had one muscular moderator band which was extended from the interventricular septum to the opposite ventricular wall especially to the papillary muscle. In left ventricle, there were two bands; one extended from the interventricular septum to the papillary muscles, and the other one was present in various places especially in the apex running as a thin thread-like band across the left ventricular wall. Histological examination revealed that the moderator band consisted of two major layers; the central (core) myocardium and the peripheral endocardium, acting as band capsule. The myocardium had two bundles; the contractile cardiac muscle bundles and the Purkinje fiber bundles. The endocardium consisted of three layers; the endothelial layer of Simple Squamous Epithelium, the subendothelial layer of loose connective tissue and the subendocardial layer, connecting the endocardium with the myocardium.
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Left Atrium of the Mature Dromedary Camel Heart (Camelus dromedaries): Microanatomy
Journal of Advanced Veterinary Research, 2014Co-Authors: Wael Ghonimi, Mohamed Hafez Bareedy, Ahmad Awad Abuel-atta, Ahmad BalahAbstract:The current work was carried out on the left atrium of ten healthy mature camels. The specimens were collected and examined histologically after being fixed in 10% Neutral Buffered Formalin. The atrium was processed till paraffin sections obtained and stained. Microscopically, the left atrium is consisted of three major tunics; the internal endocardium, the middle myocardium, and the external epicardium. The endocardium is the inner layer of the atrial wall and consisting of the endothelial layer of Simple Squamous Epithelium that lining the atrium, subendothelial layer of loose connective tissue supporting the endothelium and the subendocardial layer that connecting the endocardium with the myocardium. Myocardium is the middle layer of the atrium, forming the main mass of the atrial wall. It is sandwiched between an outer epicardium, that covers the atrium, and an inner endocardium, that lines the atrial chamber. It is mainly formed from bundles of the contractile cardiac myocytes; myocardiocytes that arranged in strands or branching columns. The left atrium is externally covered with the epicardium that is relatively thin in comparison with the myocardium and consisting of a subepicardial layer of highly vascularized loose connective tissue and the mesothelium of Simple Squamous Epithelium.
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Left Ventricles of the Mature Camel Heart (Camelus dromedaries) with Special References to the Structure and Distribution of the Purkinje Cardiomyocytes: Microanatomy
Journal of Veterinary Science & Technology, 2014Co-Authors: Wael Ghonimi, Mohamed Hafez Bareedy, Ahmad Awad Abuel-atta, Ahmad BalahAbstract:The present investigation was performed to clarify the histological features of the left ventricles in the heart of the mature dromedary camel. This investigation was carried out on the left ventricles of six healthy mature camels. Microscopically, the left ventricles is consisted of three major layers or tunics; the internal endocardium, the middle myocardium, and the external epicardium. The endocardium is consisted of three layers; the endothelial layer of Simple Squamous Epithelium, subendothelial layer of loose connective tissue and the subendocardial layer that connecting the endocardium with the myocardium and housing bundles of the purkinje cardiomyocytes; purkinje fibers. The myocardium, is the middle layer of the ventricular wall, is sandwiched between an outer epicardium, that covers the ventricular wall, and an inner endocardium, that lines the chamber, containing two bundles of cardiac fibers; the working cardiac myocytes (myocardiocytes) and the purkinje bundles. The epicardium is the outer most layer of the ventricular wall. This layer is a relatively thin in comparison with the myocardium and is consisted of a subepicardial layer of loose connective tissue which housing many blood vessels, lymph vessels, nerves and adipocytes and mesothelium of Simple Squamous Epithelium.
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Papillary Muscles in the Heart Ventricles of the Mature Dromedary Camel (Camelus dromedaries) with Special References to the Chordae Tendineae:Gross and Microanatomy
Journal of Cytology & Histology, 2012Co-Authors: Wael Ghonimi, Mohamed Hafez Bareedy, Ahmad Awad Abuel-atta, Ahmad BalahAbstract:The present investigation was carried out on the papillary muscles of ten healthy mature dromedary camels. Anatomically, the papillary muscles are muscular projections from the walls of the right and left ventricles into their cavities. They are processing many nipples like processes. The apex of each muscle process is attached to cord-like tendons; chordae tendineae. The latter, are string-like in appearance and are sometimes referred to as "heart strings" that linking the papillary muscles to the tricuspid valve in the right ventricle and the mitral valve in the left ventricle. These cords divided, in turn, into sub branches before attaching to the apex, body and base of the cusp, , preventing eversion of the valve leaflets into the atria during the ventricular contraction. So histologically, there are great invasions of the chordae tendineae to inside the papillary muscles. These chordae tendineae are observed highly branched looked like the tree roots and the finger like projections in between the cardiac muscle fibers within the papillary muscles. Histologically, the papillary muscle is consisting of two major layers; the central myocardium and the peripheral endocardium which act as a capsule. The myocardium has two bundles; the contractile cardiomyocytes bundles and the purkinje cardiomyocytes bundles. The papillary muscles are completely covered externally by a single layer of Simple Squamous Epithelium; endothelium that is reflected from the ventricular endothelium. The latter, is supported by a subendothelial loose connective tissue that is mainly composed of collagen and elastic fibers.
John P. Wourms - One of the best experts on this subject based on the ideXlab platform.
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Maximization of evolutionary trends for placental viviparity in the spadenose shark,Scoliodon taticaudus
Environmental Biology of Fishes, 1993Co-Authors: John P. WourmsAbstract:Placental viviparity has evolved in Scoliodon taticaudus to a degree that rivals some eutherian mammals. Its eggs are the smallest known of any shark. They have a diameter of 1 mm, a dry weight of 0.0654 ± 0.0100 mg and are nearly yolk-free. Implantation takes place at an early (3 mm) stage of development, and gestation is short (5–6 months). Comparison of the dry weight of the egg (0.065 mg) with the estimated dry weights of a mid-late term 90 mm embryo (910 mg) and a 152 mm neonate (3815.4 mg) reveals weight changes of 14219 × and 58338 ×, respectively. Its normalized brood weight, a measure of maternal nutrient investment, is 49.5 g · kg^−1 female body weight for a six-month gestation. Comparisons with other species of placental and nonplacental sharks show that S. laticaudus has a highly advanced form of matrotrophy. Maternal nutrients appear to be acquired by placental transport and by imbibition of uterine fluid. Hemotrophic placental nutrient transfer occurs across a unique uterine implantation site, termed the trophonematous cup, in which maternal blood appears to bathe the outer Epithelium of the embryonic yolksac placenta. The latter is solid and filled with a three-dimensional network of capillaries and many free interstitial cells. The umbilical stalk contains the vitelline vessels but lacks a yolk duct. Its surface is amplified by many long, villous appendiculae, which consist of a vascular core that ramifies into a massive surface capillary network invested by a Simple Squamous Epithelium. The appendiculae of S. laticaudus most likely are sites of gas exchange and possibly the uptake of small molecules. They are unlike the appendiculae described in any other placental shark and exhibit design principles similar to those of the uterine trophonemata of matrotrophic rays.
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Maximization of evolutionary trends for placental viviparity in the spadenose shark, Scoliodon laticaudus
The reproduction and development of sharks skates rays and ratfishes, 1993Co-Authors: John P. WourmsAbstract:Placental viviparity has evolved in Scoliodon laticaudus to a degree that rivals some eutherian mammals. Its eggs are the smallest known of any shark. They have a diameter of 1 mm, a dry weight of 0.0654 ± 0.0100 mg and are nearly yolk-free. Implantation takes place at an early (3 mm) stage of development, and gestation is short (5–6 months). Comparison of the dry weight of the egg (0.065 mg) with the estimated dry weights of a mid-late term 90 mm embryo (910 mg) and a 152 mm neonate (3815.4 mg) reveals weight changes of 14219 × and 58338 ×, respectively. Its normalized brood weight, a measure of maternal nutrient investment, is 49.5 g • kg−1 female body weight for a six-month gestation. Comparisons with other species of placental and non-placental sharks show that S. laticaudus has a highly advanced form of matrotrophy. Maternal nutrients appear to be acquired by placental transport and by imbibition of uterine fluid. Hemotrophic placental nutrient transfer occurs across a unique uterine implantation site, termed the trophonematous cup, in which maternal blood appears to bathe the outer Epithelium of the embryonic yolksac placenta. The latter is solid and filled with a three-dimensional network of capillaries and many free interstitial cells. The umbilical stalk contains the vitelline vessels but lacks a yolk duct. Its surface is amplified by many long, villous appendiculae, which consist of a vascular core that ramifies into a massive surface capillary network invested by a Simple Squamous Epithelium. The appendiculae of S. laticaudus most likely are sites of gas exchange and possibly the uptake of small molecules. They are unlike the appendiculae described in any other placental shark and exhibit design principles similar to those of the uterine trophonemata of matrotrophic rays.
Han Chang-hee - One of the best experts on this subject based on the ideXlab platform.
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Ultrastructure and Role of Somatic Cells in Macrobrachium nipponense Testis
Korean Journal of Fisheries and Aquatic Sciences, 2000Co-Authors: Kim Dae-hyun, Kang Jung-ha, Han Chang-heeAbstract:Ultrastructure and function of testis somatic cells in freshwater prawns Macrobrachium nipponense were studied. The paired testes of the prawn were elongated, united at their anterior end, which lay between the dorsal surface of the hepatopancreas and the heart. Each testis consisted of a large number of seminiferous cords compactly held together by connective tissue. A seminiferous cord was composed of an outer layer of Simple Squamous Epithelium, a basement membrane, the closely packed germ cells and sustentacular cells of the germinal ridge, and an inner layer of Simple cuboidal epithelial cells. Leydig cell-like cells in an angular areas filling the space of the seminiferous cords were observed. The nuclei of leydig cell-like cells were characterized by a distinct nucleolus. The Simple Squamous epithelial layer was composed of flattened cells tying on a basement membrane. The nuclei of the flattened cells were often overlapped in a layer, and the cytoplasm of the cells was observed just near the nuclei. The sustentacular cells were complex in morphology. These cells had relatively small cell bodies from which long cytoplasmic extensions ramified reached the space of germ cells in the germinal ridge. The nuclei of sustentacular cells usually exhibited angular profiles and located most commonly at the periphery of the cords. Cells of Simple cuboidal Epithelium located between germinal ridge and lumen of seminiferous cord, and part of the cells were adjacent to basal lamina, The cuboidal epithelial cells contained numerous mitochondria, the well-developed rER, the well-developed Golgi complex, and irregularly shaped nuclei. Transition vesicles appeared on the cis side of the Golgi complex. The large vesicles on the trans side of the complex appeared to fuse to form a membrane-bound structure. A number of pits on the cell apex suggested exocytotic activity for secretion of the sperm supporting matrix.