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Wearable Sensors for Blood Perfusion Monitoring in Patients with Diabetes Mellitus
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Evgenii A. Zherebtsov, Elena V. Zharkikh, Yulia I. Loktionova, Angelina I. Zherebtsova, Viktor V. Sidorov, Alexander I. Krupatkin, Andrey V. Dunaev
The blood capillaries are responsible for delivering fluids to tissues, and the venules are known as the channels for carrying proteins. About 5%–10% of the capillary-venule filtrate is transported from the tissue to the lymph, and about 2–4 L of lymph per day is returned to the circulation. The lymphatic capillaries (LC) are blind vascular tubes with diameters ranging from 20 to 200 μm or, more often, from 10 to 60 μm (for comparison, blood capillaries are about 4–8 μm in diameter). In the English scientific literature, these capillaries are called initial, or terminal, lymphatics. When the hydrostatic pressure of the interstitium is higher than that in the LC, interendothelial junctions are extended, peculiar pores (primary valves) of about 2 μm diameter are formed, and resorption occurs. When the pressure equilibrates, the endothelial cells close together, and the fluid ceases to flow into the lymphatic capillaries.
The Cause of Pressure Sores
Published in J G Webster, Prevention of Pressure Sores, 2019
The capillary wall is a thin membrane made up of endothelial cells. Substances pass through the junctions between endothelial cells and some also pass through the cells by either vesicular transport, filtration, or diffusion for lipid-soluble substances. Diffusion is the most important in terms of the exchange of nutrients and waste materials between blood and tissue. Glucose and oxygen are higher in concentration in the bloodstream than in the interstitial tissues so they diffuse into them. CO2 diffuses in the opposite direction. The rate of filtration at any point along a capillary depends upon a balance of forces called Starling forces. One of these forces, the hydrostatic pressure gradient, is the hydrostatic pressure in the capillary minus the hydrostatic pressure in the interstitial fluid. Due to these forces, substances tend to leave blood capillaries where they begin by the arterioles and enter them as they end near the venules.
Vimentin and Desmin
Published in Masahiko Mori, Histochemistry of the Salivary Glands, 2019
Pleomorphic adenomas are composed of duct-like structures which are of two types; one is luminal tumor cells from ductal origin, and the other is spindle-shaped cells of myoepithelial origin. Vimentin staining with monoclonal antibodies occurred rarely in stromal connective tissue fibers of tumors (Figure 2 a). Vimentin was positive in connective tissue fibers accompanying modified myoepithelial cells (Figure 2 b, c). Large epithelial foci showed no staining for vimentin with monoclonal antibodies, but occasionally variable staining in peripherally located tumor cells was noted (Figure 2 c, d). Hyalin-like and myxomatous tissues failed to stain with monoclonal antibodies to vimentin, except for capillary vessels and associated collagen fibers which were strongly reactive (Figure 2 d). Endothelial cells of blood capillaries stained abundantly.
Heat distribution and the condition of hypothermia in the multi-layered human head: A mathematical model
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Ahsan Ul Haq Lone, M.A. Khanday, Saqib Mubarak, Feroze A. Reshi
Circulatory system also plays a pivotal role in the thermoregulation of body temperature in humans by regulating the temperature distribution throughout the body. Blood capillaries permeate almost every part of the body and perform the function of heat distribution within the body and also heat exchange with the environment. Figure 4 highlights the variation of temperature in human head in relation to the temperature at head-atmosphere interface. Head receives a number of arteries that deliver blood to brain and scalp and also facilitate the distribution and regulation of temperature in the head. The capillaries running through the head and reaching the surface of the head enable blood-mediated convective heat transfer from atmosphere to the core head (Coccarelli et al. 2017). When a human head exposed to cold environment, the blood capillaries present in the scalp exchange body heat with the external cold environment and consequently, experience lowering in the temperature of the blood in the scalp. Continued exposure to cold environment transmits the effect deep into the brain capillaries, wherein the temperature gradually lowers down below the normal body temperature. This decrease in arterial blood temperature in the head as function of the duration of exposure of the head to cold environment is reflected in Figure 4.
Subcutaneous catabolism of peptide therapeutics: bioanalytical approaches and ADME considerations
Published in Xenobiotica, 2022
Simone Esposito, Laura Orsatti, Vincenzo Pucci
The ECM plays a major role in peptide absorption, since it controls the content and the movements of the subcutaneous interstitial fluid (SIF) from and to the cardiovascular and the lymphatic systems (Richter et al. 2012). Vascular permeability depends on the presence of a size barrier, which is regulated by the interendothelial junctions of blood and lymph vessels. Blood capillaries have tighter junctions than lymph vessels, therefore they form a more restrictive barrier to macromolecules (Reitsma et al. 2007; Ono et al. 2017). Together, glycocalyx and interendothelial junction act as a molecular sieve towards fluids, small molecules and proteins that are filtered from blood through capillary walls towards the SIF, and then are either reabsorbed back into the capillaries or taken up by the lymphatic system (Fogh-Andersen et al. 1995; Richter et al. 2012; Moore and Bertram 2018; Torres-Terán et al. 2021). A correlation between the molecular weight of macromolecules and their lymphatic uptake was first proposed by Supersaxo et al. (Supersaxo et al. 1990). Drug peptides SC administered can reach the systemic circulation by blood capillaries or lymphatic vessels uptake. Proteins with high MW (>16kDa) have limited transport into the blood capillaries and are taken up by lymphatic capillaries and lymph nodes and enter the blood circulation through the thoracic duct (Porter and Charman 2000; Kagan 2014).
Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin
Published in Ultrastructural Pathology, 2021
Abd El-Fattah B. M. El-Beltagy, Amira M.B. Saleh, Amany Attaallah , Reham A. Gahnem
In control and neem supplemented groups, the renal corpuscle appeared with normal ultrastructure architecture whereas it consisted of the glomerulus and Bowman’s capsule. The glomerulus consisted of tufts of blood capillaries that lined with capillary endothelium. The endothelial cells lining the capillary lumen are characterized by their protruding nuclei inside the glomerular basal lamina (BL) without clearly visible cytoplasm and regularly perforated with fenestrations. Also, the capillary loops are supported by little and irregular mesangial cells which characterized by their electron dense cytoplasm. Bowman’s capsule consisted of outer parietal layer and inner visceral layer. The parietal layer represented by a single layer of flattened squamous epithelium with centrally located nuclei. The visceral layer composed of podocytes, from which arise several primary processes or pedicles. Each primary process gives rise secondary processes. The latter processes were in direct contact with the BL of the glomerular capillaries. The filtration slits between secondary processes of podocytes appeared with regular diameter (Figure 3A&B).