Bert Flemming

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PURPOSE To compare changes in urinary viscosity in the renal tubules following administration of a high-viscosity iso-osmolar contrast agent (iodixanol) to that observed following administration of a less viscous, higher osmolar contrast agent (iopromide) in anesthetized rats. MATERIALS AND METHODS A total of 43 rats were studied. Experiments were(More)
20-Hydroxyeicosatetraenoic acid (20-HETE) production is increased in ischemic kidney tissue and may contribute to ischemia/reperfusion (I/R) injury by mediating vasoconstriction and inflammation. To test this hypothesis, uninephrectomized male Lewis rats were exposed to warm ischemia following pretreatment with either an inhibitor of 20-HETE synthesis(More)
Previous studies have suggested a link between renal metabolism and local kidney hemodynamics to prevent potential hypoxic injury of particularly vulnerable nephron segments, such as the outer medullary region. The present study used three different inspiratory oxygen concentrations to modify renal metabolic state in the conscious rat (hypoxia 10% O2,(More)
AIM X-ray contrast media (CM) can cause acute kidney injury (AKI). Medullary hypoxia is pivotal in CM-induced AKI, as indicated by invasively and pin-point measured tissue oxygenation. MRI provides spatially resolved blood oxygenation level-dependent data using T2 * and T2 mapping. We studied CM effects on renal T2 */T2 and benchmarked them against short(More)
Acute kidney injury of various origins shares a common link in the pathophysiological chain of events: imbalance between renal medullary oxygen delivery and oxygen demand. For in vivo assessment of kidney haemodynamics and oxygenation in animals, quantitative but invasive physiological methods are established. A very limited number of studies attempted to(More)
Renal tissue hypoperfusion and hypoxia are key elements in the pathophysiology of acute kidney injury and its progression to chronic kidney disease. Yet, in vivo assessment of renal haemodynamics and tissue oxygenation remains a challenge. Many of the established approaches are invasive, hence not applicable in humans. Blood oxygenation level-dependent(More)
Response of renal vasculature to changes in renal perfusion pressure (RPP) involves mechanisms with different frequency characteristics. Autoregulation of renal blood flow is mediated by a rapid myogenic response and a slower tubuloglomerular feedback mechanism. In 25 male conscious rats, ramp-shaped changes in RPP were induced to quantify dynamic(More)
AIM To determine if the internal limiting membrane (ILM) was present in the epiretinal membrane (ERM) when we deliberately tried to perform a "double peel" for macular pucker. METHODS Pars-plana vitrectomy and a "double peel" were carried out. The ERM and ILM were stained with Trypan Blue and peeled separately over the same area. The amount of ERM present(More)
Patients on chronic hemodialysis were divided into two groups: normotensive patients (group I) and renal hypertensive patients treated with antihypertensives (group II). The sodium and potassium contents in red blood cells ([Na+]i, [K+]i), ouabain-resistant net sodium uptake (ORNa+ uptake, phi Na), the relative ORNa+ uptake (k), the mean cell hemoglobin(More)
Contrast-induced nephropathy is a common cause of acute renal failure, and the mechanisms underlying this injury are not completely understood. We sought to determine how physicochemical properties of contrast media may contribute to kidney damage in rats. We administered contrast media of equivalent iodine concentrations but differing physiocochemical(More)