A mathematical model of the urine concentrating mechanism in the rat renal medulla
15-19 Infusion of contrast materials with the resultant increase in osmotic load and viscosity, increases hypoxemia of the renal medulla
and renal free radical production through post-ischemic oxidative stress.
The intravascular volume expansion was believed to prevent the adverse effect of contrast media administration by 2 distinct mechanisms: (1) reducing the vasoconstrictive effect of contrast media on renal medulla
by suppression of vasopressin secretion, inhibition of renin-angiotensin-aldosterone system, and increase of prostaglandin synthesis, and (2) attenuating the direct toxic effect of contrast media on renal tubular epithelial cells by decreasing proximal tubular salt and water reabsorption which results in diluting the intratubular fluid and reducing the intratubular viscosity .
was homogenized in a mixture of phenol and guanidine isothiocyanate (TRIzol, 15596-026, Invitrogen, USA) using a Polytron PT 1200 (Kinematica, Switzerland) and stored at -80[degrees]C until the processing of total RNA extraction.
showed closely packed cross sections of collecting ducts, thin descending limb and thick ascending limbs of loop of Henle.
The level of 8-OHDG, a marker of oxidized nucleosides in DNA, was higher in the tissue sections of the brain, testes, and renal medulla
of 30-week-old SHRs than in 30-week-old WKY rats.
Pathologically, the renal medulla
is characterized by anoxia, hyperosmolarity and low pH that promote hemoglobin S polymerization and red blood cell sickling.
High CM viscosity is a key element in the pathophysiology of CIAKI, because the hyperosmolar environment of the renal medulla
results in CM enrichment in both the tubules and the vasculature.
The protective effect of fenoldopam may increase blood flow of the renal medulla
in patients at risk of CIN5.
The renal ultrasound showed hyperechoic regions in the renal medulla
consistent with bilateral nephrocalcinosis.
Hypoxia of the renal medulla
Its implications for disease.
The mechanism of radiocontrast nephropathy is complex and may include direct toxic effect on cell proliferation and mitochondrial function, and formation of free radicals in an acidic environment in the renal medulla
resulting in vasoconstriction and ischaemia (2-4).