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Engineered Nanoparticles for Drug Delivery in Cancer Therapy *
Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Tianmeng Sun, Yu Shrike Zhang, Pang Bo, Dong Choon Hyun, Miaoxin Yang, Younan Xia
Before draining into urine, nanoparticles may still have a chance to be resorbed from the tubular fluid. Studies have shown that some nanoparticles based on polyamine dendrimers may undergo proximal tubule resorption [165]. Further studies are still needed to evaluate the resorption of nanoparticles as the capability of nanoparticles to be resorbed is still an open question.
The Loop of Henle and Production of Concentrated Urine
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
For the formation of a concentrated (hyperosmotic) urine water must be removed from the tubular fluid leaving the solute behind. Water, however, can only move passively from an area of low osmolality to one of high osmotic pressure. Therefore, in order to remove water from the tubular fluid, the kidney has to create an area of high osmotic pressure outside the nephron. This is achieved by the loop of Henle.
Sodium Intake and Hypertension
Published in Austin E. Doyle, Frederick A. O. Mendelsohn, Trefor O. Morgan, Pharmacological and Therapeutic Aspects of Hypertension, 2020
T. O. Morgan, F. A. O. Mendelsohn, A. E. Doyle
In addition to the reabsorption of sodium ions which is associated with the reabsorption of bicarbonate, there is also absorption of sodium chloride. Sodium ions are actively transported, and the absorption of chloride ion is coupled electrogenically. Alternatively, there may be a neutral sodium chloride pump. In the proximal tubule, approximately 70% of sodium ions filtered are absorbed, whereas only about 60% of the chloride ions filtered are absorbed (Table 1). At the end of the proximal tubule, the tubular fluid is isoosmotic and consists mainly of sodium chloride. The volume amounts to approximately 30% of the volume filtered. Reabsorption of sodium chloride probably continues in the straight portion of the proximal tubule, which, however, is not accessible for study.
Clinical pharmacology of SGLT-2 inhibitors in heart failure
Published in Expert Review of Clinical Pharmacology, 2023
Maria Velliou, Effie Polyzogopoulou, Ioannis Ventoulis, John Parissis
The existing clinical evidence suggests that SGLT2 inhibitors are one The existing clinical evidence suggests that SGLT2 inhibitors are one one and areresponsible for the coupled reabsorption of filtered glucose and sodium in a 1:1 molar ratio. The SGLT2i work by inhibiting the SGLT2 receptors, and, thus, they result in glucosuria and natriuresis. Glucose that has not been reabsorbed flows into the distal tubule, where it increases tubular fluid osmolarity and reduces passive reabsorption of electrolyte-free water, particularly in the collecting duct [56]. The RECEDE-CHF trial (SGLT2 Inhibition in Combination With Diuretics in HF) demonstrated that empagliflozin led to a significant increase in 24-hour24-h urine volume and electrolyte-free water clearance among patients with type 2 DM and HF who were receiving regular furosemide. This observation suggests a synergistic effect between SGLT2i and background diuretic treatment in HF [57].
Kidney stone proteomics: an update and perspectives
Published in Expert Review of Proteomics, 2021
Paleerath Peerapen, Visith Thongboonkerd
CaOx is the most dominant type of kidney stones found in approximately 80% of the stone formers (patients carrying kidney stones) [7,34,35]. The crystalline compositions of CaOx stones include CaOx monohydrate (COM) and/or CaOx dihydrate (COD) crystals [7,34,35]. CaOx kidney stones can initiate primarily inside renal tubular lumens or outside (at the renal interstitium). Within the renal tubules, crystalline components are crystallized as the result of supersaturation of ions in the renal tubular fluid [36,37]. The tiny crystals can adhere onto apical surface of renal epithelial cells, and this process is facilitated by cellular injury [36–38]. In addition, free crystals can further grow and self-aggregate [36,39,40]. When their sizes are big enough, they cannot pass through the intratubular lumens and then get stuck inside the renal tubular segments [36]. The deposited crystals then act as the nidus for further enlargement and the stone starts to form. For the interstitium mechanism, supersaturation of calcium phosphate (CaP) is common within the interstitial compartment leading to the formation of plaque, namely Randall’s plague [41,42]. Together with inflammatory response, some plaques erode into the urinary space or pelvis, where they are exposed to the supersaturated calcium and oxalate ions [41,42]. The Randall’s plaque then serves as the nidus for CaOx crystals to deposit and to form the stone [42–44].
Kidney physiology and pathophysiology during heat stress and the modification by exercise, dehydration, heat acclimation and aging
Published in Temperature, 2021
Christopher L. Chapman, Blair D. Johnson, Mark D. Parker, David Hostler, Riana R. Pryor, Zachary Schlader
The kidneys are vital in regulating body fluid volume and composition and there are many systemic and intrarenal mechanisms underlying water and electrolyte regulation. The ability of the kidneys to concentrate urine arises from interactions among the active transport of NaCl from the thick ascending limbs (i.e., sodium reabsorption), water permeability of the collecting ducts, delivery rate of NaCl and water to the loop of Henle, and the volume of tubular fluid delivered to the medullary collecting ducts, which increases osmotic water transport across the epithelium of the collecting duct [203]. Most of the techniques used to quantify changes in water and electrolyte regulation require collection of timed urine samples and, depending on the measurements, blood draws (e.g., fractional excretion calculations, hormones). Thus, the measurements presented in this section typically reflect a systemic response to changes in water and electrolyte regulation.