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A patient with high blood pressure
Published in Tim French, Terry Wardle, The Problem-Based Learning Workbook, 2022
Thiazide diuretics reduce salt and water reabsorption in the distal convoluted tubule. Consequently, initial falls in BP are thought to occur due to a reduction in total blood volume, venous return and cardiac output. Cardiac output does return to normal, but the antihypertensive effect persists as the peripheral resistance has decreased.
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
During water deprivation, the distal convoluted tubule reabsorbs sodium and chloride but remains impermeable to water, and the fluid leaving the tubule still has an osmolality of less than 100 mOsm/kg H2O. ADH changes the permeability of the collecting duct wall so that it becomes permeable to water. In the presence of ADH, tubular fluid leaving the cortical collecting duct has an osmolality of 300 mOsm/kg H2O (the same as cortical interstitial fluid osmolality). With ADH, the medullary collecting duct reabsorbs much water because of the high medullary interstitial fluid osmolality produced by the loop of Henle, and a small volume of concentrated urine of osmolality 1400 mOsm/kg H2O is excreted (the obligatory urine loss). Urea accounts for half of the osmolality of this concentrated urine, and sodium, chloride, potassium, creatinine and other solutes account for the remainder (Figure 44.3).
Renal
Published in Sarah Armstrong, Barry Clifton, Lionel Davis, Primary FRCA in a Box, 2019
Sarah Armstrong, Barry Clifton, Lionel Davis
The nephron begins at the glomerulus with the invagination of glomerular capillaries into Bowman's capsule and continues through the proximal convoluted tubule (PCT), loop of Henle (LOH) and distal convoluted tubule (DCT), ending at the collecting ducts
Respiratory management in the premature neonate
Published in Expert Review of Respiratory Medicine, 2023
Vikramaditya Dumpa, Indirapriya Avulakunta, Vineet Bhandari
Thiazide diuretics act at the distal convoluted tubule to inhibit reabsorption of NaCl. They are less potent compared to loop diuretics but carry the side effects of electrolyte disturbances. Similar to loop diuretics, their use has been shown to improve pulmonary mechanics in some studies, but a Cochrane review (n = 6 RCTs) on the use of thiazides concluded that there is no benefit of routine use of thiazide diuretics therapy in preterm infants with BPD [147–149]. Not surprisingly, in the absence of good evidence and lack of consensus, there is currently a wide variation in the use of diuretics in preterm infants [143,144]. We do not recommend routine use of diuretics in the management or prevention of premature lung disease. Their use can be considered on an individual basis in those preterm infants with pulmonary edema to improve short-term outcomes, but attention must be paid to the fluid and electrolyte status.
Resveratrol: a panacea compound for diazinon-induced renal toxicity
Published in Toxin Reviews, 2023
Maryam Esfahani, Amir Hossein Rahbar, Sara Soleimani Asl, Fereshteh Mehri
Histopathological assessments of the H&E stained of the kidney tissue are shown in Figure 1(A–E). In the present study, the structure of the kidney and Bowman’s capsule was normal in the control group. The urinary space was not dilated, and the distal convoluted tubule and the proximal convoluted tubule were intact (Figure 1(A)). DZN rats had renal damage compared with control rats. The urinary space, the distal convoluted tubule, and the proximal convoluted tubule were dilated. Vascular congestion and cell infiltration were evident and the epithelial cohesion of the Bowman’s capsule was lost (Figure 1(B)). Based on the findings, the severity of lesions reduced in the DZN + different doses of Res groups. The Bowman’s capsule epithelium was more cohesive, and the dilatation of the urinary space and distal convoluted tubule represented a reduction. These changes were observed in parallel with the increasing dose of Res (Figure 1(C–E)). Accordingly, the TI index in the control group was zero and was not observed geological cases. Due to the presence of atrophy and vacuolation of the epithelium as well as cell infiltration and calcium crystals, the damage was in the severe in diazinon group. Injury rate decreased in the resveratrol groups, so that it was moderate in the low and medium dose groups and mild in the high dose group. Evaluation in regarding the extent of kidney tissue damage was used using studies conducted by Toblli et al. (1999).
The pharmacotherapeutic options in patients with catecholamine-resistant vasodilatory shock
Published in Expert Review of Clinical Pharmacology, 2022
Timothy E. Albertson, James A. Chenoweth, Justin C. Lewis, Janelle V. Pugashetti, Christian E. Sandrock, Brian M. Morrissey
The endogenous hormone vasopressin circulates in the blood after it is released from the posterior pituitary gland. VP mainly ensures osmoregulation by its effect on the arginine vasopressin receptor 2 (AVPR2) located primarily in the distal convoluted tubules promoting water retention. The antidiuretic hormone effect is normally the major effect of VP, but in shock conditions, even higher circulatory levels of VP are naturally released. These higher levels also stimulate arginine vasopressin receptor 1a (AVPR1a) generating powerful vasoconstriction. Potentially when VP is given exogenously, it maintains better kidney perfusion than exogenous NE because there are more AVPR1a receptors in the glomerular efferent than afferent arterioles [21]. In addition, the stimulation of arginine vasopressin receptor 1b (AVPR1b) by VP generates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary resulting in release of cortisol from the adrenal gland. The higher levels of ACTH generated by VP release generate increased natural levels of endogenous cortical steroids in shock patients.