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Mechanisms of Chemically Induced Glomerular Injury
Published in Robin S. Goldstein, Mechanisms of Injury in Renal Disease and Toxicity, 2020
The interlobular arteries of the kidney branch extensively to form afferent arterioles which supply each glomerulus. The glomerulus nearly fills Bowman’s capsule. The glomerulus is not simply a coiled capillary, but rather a capillary network; as the afferent arteriole enters Bowman’s capsule, it expands into a relatively wide chamber, which branches into five to eight trunks. The subdivisions of each trunk constitute a separate glomerular lobule. For a given glomerulus, some 20 to 40 capillary loops are grouped into 5 to 8 or more lobules. Within a lobule, numerous anastomoses join the capillary loops.10
Anatomy & Embryology
Published in Manit Arya, Taimur T. Shah, Jas S. Kalsi, Herman S. Fernando, Iqbal S. Shergill, Asif Muneer, Hashim U. Ahmed, MCQs for the FRCS(Urol) and Postgraduate Urology Examinations, 2020
Roughly a quarter of the cardiac output is supplied to the kidneys via the paired renal arteries. They branch from the aorta at the level of L2 just below the origins of the superior mesenteric (SMA) and adrenal arteries. The right artery passes behind the inferior vena cava (IVC) first, in contrast to the left, which passes almost directly to the kidney. Before entering the hilum, each artery initially gives off a single posterior segmental branch that passes behind the renal pelvis to supply the posterior aspect of the kidney. It can cause obstruction of the pelvi-ureteric junction if it passes in front of the ureter. After entering the hilum, the artery commonly divides into four anterior segmental branches (apical, upper, middle and lower). The divisions and blood supply of the anterior and posterior segmental arteries give rise to a longitudinal avascular plane, known as Brodel’s line, 1–2 cm posterior to convex border of the kidney. Segmental arteries give rise to lobar arteries within the renal sinus, which become interlobar arteries that lie in between the Columns of Bertin in the parenchyma. These give off arcuate branches, which become the interlobular arteries that eventually form the afferent arteries of the glomeruli. The renal vein lies in front of the artery in the renal hilum. The right vein is 2–4 cm in length in comparison to the left, which may be up to 10 cm. The left renal vein reaches the IVC by passing behind the SMA and in most cases in front of the aorta.
The kidneys
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Microscopically, in the small granular kidneys, it is common to find all degrees of hyalinization of glomeruli. Many are completely hyalinized and some show partial destruction. A small percentage is normal or nearly so, and may be hypertrophied. In cases in which the kidneys are not greatly shrunken the glomeruli are usually more uniformly damaged: this is seen in the chronic end-stages of membranous and mesangiocapillary glomerulonephritis. The arcuate and interlobular arteries, and the afferent arterioles, show hypertensive changes. Where malignant hypertension has supervened, secondary glomerular changes are seen in those glomeruli not already destroyed by the glomerulonephritic process.
Correlation between serum cystatin C level and renal microvascular perfusion assessed by contrast-enhanced ultrasound in patients with diabetic kidney disease
Published in Renal Failure, 2022
Ping Zhao, Nan Li, Lin Lin, Qiuyang Li, Yiru Wang, Yukun Luo
The ultrasound sequences were output into digital imaging and communication in medicine (DICOM) format. Renal perfusion was analyzed in VueBox version 7.0 (Bracco SpA, Milan, Italy). Three regions of interest (ROIs) were defined: a reference ROI and two analysis ROIs. The segmental or interlobular arteries were set as the reference ROI in each kidney image and two ROI regions were set at the cortical zones in each image. The analysis ROI was placed on the middle pole to the lower pole of the renal cortex. The area of the ROI was 0.3 cm2. Movement compensation was applied to all participants. The DICOM data of the ROI were converted into echo-power data. A time-intensity curve (TIC) of the ROI was generated, from which the analysis parameters were calculated (Table 1, Figure 1). The parameters included ratio of the peak enhancement to the reference ROI (PE%); wash-in area under the curve (WiAUC, a.u.); rise time (RT, s); mean transit time (mTTI, s); time to peak (TTP, s); wash-out AUC (WoAUC, a.u.); wash-in and wash-out area under the curve (WiWoAUC, a.u.). The values obtained in the two ROIs from the leftrenal cortical zones were averaged for the analysis. To guarantee the quality of the data analysis, the goodness of fit (GOF) in all analyses was not <75%.
Intrarenal hemodynamics and kidney function in pheochromocytoma and paraganglioma before and after surgical treatment
Published in Blood Pressure, 2021
Magdalena Januszewicz, Piotr Dobrowolski, Andrzej Januszewicz, Ewa Warchoł-Celińska, Katarzyna Jóźwik-Plebanek, Daria Motyl, Marek Kabat, Mariola Pęczkowska, Ilona Michałowska, Urszula Ambroziak, Sadegh Toutounchi, Zbigniew Gałązka, Louisiane Courcelles, Marco Pappaccogli, Graeme Eisenhofer, Alexandre Persu, Jacques W. M. Lenders, Jacek Kądziela, Aleksander Prejbisz
For renal ultrasound investigation a Logiq E9 (GE, USA) ultrasound unit with multiphase 2–4 MHz convex array transducer was used. Measurements were obtained from interlobular arteries (on the level of edge of pelvis and parenchyma). Doppler US spectral analysis included mean resistance index (RRI = peak systolic velocity − end-diastolic velocity/peak systolic velocity) and pulsatility index (PI = peak systolic velocity − end-diastolic velocity/time averaged velocity) obtained from three Doppler curves at different sites of each kidney. For calculation, duplex scanner software was used. For each patient mean RRI and mean PI based on indices calculated in the left and right kidney were also calculated. Measurements were performed by two experienced investigators with interobserver and intraobserver coefficients of variance of RRI were 5.6% and 4.7%, respectively (n = 12).
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
There is great interest in accurately quantifying changes in renal blood flow because it is a highly controlled variable that has implications for the regulation of blood pressure and water and electrolytes. Thus, it is also important to note that the kidneys have an intrinsic ability to maintain blood flow at varying arterial pressures (i.e., autoregulate). Renal blood flow autoregulation is mediated by actions of the afferent arterioles and interlobular arteries and their myogenic response to constrict or relax in response to changes in perfusion pressure [173-175]. Approximately, 50% of the total autoregulatory response [176,177] rapidly occurs within 3-10 seconds [178,179], which is contributed to by unloading of the renal baroreceptors and tubuloglomerular feedback provided by the juxtaglomerular apparatus [180,181]. Tubuloglomerular feedback also results in renin release by the afferent arterioles in response to sensation of decreased NaCl delivery to the macula densa in the distal tubule [182], which ultimately ensures a relatively stable renal blood flow and glomerular filtration rate (see Glomerular filtration rate). These neural (discussed previously in Autonomic control of kidney function), hormonal (discussed previously in PHYSIOLOGY AND ASSESSMENT OF BODY WATER REGULATION), and autoregulatory mechanisms offer a complex and highly redundant control of renal blood flow to maintain homeostasis utilizing many systems.