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Kidney Structure and Physiology
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Joel M. Henderson and Mostafa Belghasem
Angiotensin II is a circulating vasoactive hormone that primarily stimulates arteriolar contraction, but has several other related eects. Angiotensin II is a powerful sodium-and water-retaining hormone. It directly increases sodium reabsorption from the renal tubules in response to decreased total body uids. Angiotensin II exhibits its eect by directly stimulating the Na-K ATPase pump on the basolateral membrane of the tubular epithelium. Angiotensin II also directly aects the adrenal cortex, by stimulating the secretion of aldosterone hormone. is further increases sodium and water reabsorption. Angiotensin II is a potent vasoconstrictor and increases the systemic vascular resistance. us, angiotensin II increases the systemic blood pressure and maintains the extracellular uid volume in the body.
Mechanobiology of Cardiac Fibroblasts
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Peter A. Galie, Jan P. Stegemann
As these results indicate, understanding the relationship between mechanical transduction and the action of biochemical factors is vital to understanding the phenotype response of cardiac fibroblasts. Serum contains a host of growth factors that affect the cardiac fibroblast, so modifying serum concentrations does not indicate specifically what factors influence phenotype. Nonetheless, other studies have investigated how several growth factors, especially those associated with fibrosis, affect the response of cardiac fibroblasts to mechanical loading. For example, angiotensin II is an important peptide in heart disease, since elevated levels are associated with fibrosis and heart failure.19–23 Studies have shown that not only are angiotensin II and other components of the RAAS system present in the myocardium, but also that static 20% strain initially reduces the expression of angiotensinogen, a key RAS substrate.24 Hence, these results indicate that static stretch diminishes the presence of the myofibroblast phenotype, since angiotensin II is an important factor in this fibroblast–myofibroblast transition. Moreover, it provides a clear example by which mechanical stimuli in the myocardium influences the biochemical environment.
Bioartificial organs
Published in Ronald L. Fournier, Basic Transport Phenomena in Biomedical Engineering, 2017
The kidney not only provides a filtration and waste removal function but also provides several other important functions that are important to the metabolic, immune, and endocrine systems of the body. For example, erythropoietin is released by specialized cells found in the kidney in response to hypoxia. Erythropoietin is a major stimulus for the production of red blood cells in the bone marrow. Uremic patients therefore suffer from anemia. Low blood pressure causes the release of renin from the juxtaglomerular cells that are found in the kidney. Renin initiates the formation of angiotensin II, a potent vasoconstrictor, that results in an increase in blood pressure. Angiotensin II also acts on the kidneys, decreasing the excretion of both salt and water. This expands the extracellular fluid volume with the result that the blood pressure is increased. The kidneys are also responsible for the conversion of vitamin D into a substance* that promotes the absorption of calcium from the intestine. Without this substance, the bones become severely weakened because of the loss of calcium. These other very important functions that are performed by the healthy kidney are therefore compromised as a result of kidney failure.
Ease of restroom access influences fluid consumption habits and health in classroom teachers
Published in International Journal of Occupational Safety and Ergonomics, 2023
Lee J. Winchester, Alison L. Hooper, Cailin J. Kerch
Although the prominence of hypertension could also be related to job-associated stressors, it was found that access to restroom breaks negatively predicted both frequency of UTIs and hypertension. Teachers who reported being able to take a restroom break whenever needed had a 45% lower incidence rate of hypertension and a 70% lower risk of UTIs. This is likely due to dehydration and inadequate water consumption since low water intake was associated with greater frequency of both UTIs and hypertension. This makes sense since infrequent flushing of the urethra promotes UTIs [15], while hyperosmolality of the blood results in hormone release that elicits vascular constriction, raising blood pressure [13]. During periods of dehydration, angiotensin II, a product of the renin–angiotensin–aldosterone system, promotes renal sodium and water retention, thereby retaining blood fluid volume [19]. Angiotensin II production, along with low blood volume, stimulates the production of arginine vasopressin to enhance water volume retention in the blood [19]. However, both angiotensin II and arginine vasopressin are potent stimulators of arterial vascular constriction. Chronic stimulation of these factors can promote endothelial dysfunction and hypertension. Thus, it is plausible that the low fluid intake associated with the teaching profession could be exacerbating the incidence of hypertension observed among teachers. Although alterations to these health measures were not directly evaluated in this research study, it is clear that there are underlying issues with teacher classroom structure that are reducing teacher health and wellness.
Drying technologies for edible insects and their derived ingredients
Published in Drying Technology, 2021
Alan-Javier Hernández-Álvarez, Martin Mondor, Irving-Alejandro Piña-Domínguez, Oscar-Abel Sánchez-Velázquez, Guiomar Melgar Lalanne
Angiotensin I-converting enzyme (ACE-I) inhibitors are the central component of the renin–angiotensin system, and this enzyme has a major role in the regulation of blood pressure. These type of peptides from a wide variety of sources have been studied in recent decades due to the increase of chronic degenerative diseases in the population.[97] Non-hydrolyzed proteins of dried powder of Tenebrio molitor larvae showed low ACE-I inhibition (2%), while proteins that had DH higher than 20% exhibited a higher ACE inhibition, with the novel peptide Tyr-Ala-Asn being the most active against ACE-I.[91] This illustrates the potential of insect protein hydrolysates as an antihypertensive ingredient in functional foods or as a dietary supplement or even a pharmaceutical product.[98]
Development and validation of novel HPTLC method for the simultaneous estimation of Amlodipine Besylate and Telmisartan in tablet dosage form using ICH Q2 (R1) directions
Published in Journal of the Chinese Advanced Materials Society, 2018
Tomleshkumar B. Deshmukh, Sujata S. Deo, Farhin S. Inam, Trimurti L. Lambat
Telmisartan (TEL), chemically it is 4-{[4-methyl-6-(1-methyl-1H-benzimidazole-2-yl)-2-propyl-1H-benzimidazole-1-yl]methyl}-2-biphenyl carboxalic acid.[4] It is an antihypertensive drug [5] having popularity in phamecutical network. It is a new angiotensin-II receptor antagonist that is highly selective for type-I angiotensin-II receptor. Angiotensin-II is the principle pressure agent of the rennin-angiotensin system with effects that comprise renal reabsorption of sodium, vasoconstriction, stimulation of synthesis and release of aldosterone cardiac stimulation.[6] Amlodipine Besylate and Telmisartan are widely used in the treatment of hypertension and available in market in the form of combined dosage form. Literature review reveals that the methods have been reported for AMB and TEL alone or in combined dosage forms are such as RP-HPLC,[7–9] spectrophotometric,[10,11] high performance thin layer chromatography (HPTLC),[12,13] voltammetry and ion-pair chromatographic method [5,14–16] and LC-MS methods.[17]