Uptake and phosphorylation of thiamine in rabbit primary proximal tubule cells and Madin Darby canine kidney cells. II. Effect of ethanol.

Uptake of [14C]thiamine was studied in renal primary proximal tubule cells and in Madin Darby Canine Kidney cells in culture. Findings were compared with data for the accumulation of [14C]thiamine and its phosphorylation in renal cortical slices. There was a saturable component for thiamine uptake in all cell types.

Uptake and phosphorylation of thiamine in rat kidney cortical slices. I. Effect of ethanol.

Processes involved in the disposition of thiamine within the kidney were studied in rat kidney slices. Uptake of [14C]thiamine and its metabolism to [14C]thiamine phosphate were measured with and without the presence of ethanol. Whereas slice to medium ratios of 3.

Small animal magnetic resonance imaging: a means of studying the development of structural pathologies in the rat brain.

Small animal magnetic resonance imaging (SAMRI) was developed to detect structural tissue changes associated with disease states in animal models. The disease state of particular interest here is that associated with long-term alcohol abuse. The small animal model used for this study was the thiamine-deficient Sprague-Dawley rat, a model that provides a relatively rapid means of mimicking the ventriculomegaly frequently found in human chronic alcohol abusers.

Regulation of Na+, K(+)-ATPase by chronic ethanol exposure of PC 12 cells.

The effects of chronic ethanol exposure on Na+, K(+)-ATPase were investigated in PC 12 cells. Inclusion of ethanol in the Na+, K(+)-ATPase assay (i.e.

Brain osmoregulation during extreme and moderate dehydration in a rat model of severe DKA.

To determine if osmoprotective molecules accumulate in the brain during severe DKA with extreme (DKA-E) and moderate (DKA-M) dehydration, Fischer 344 rats (250-350g) were given STZ 45 mg/kg (i.p.) and allowed food and water ad lib.

MR imaging of normal rat brain at 0.35 T and correlated histology.

A custom-built small-animal transceiver was used for in vivo imaging of normal rat brain at 0.35 T, with the objective of identifying anatomic components by comparison of images with corresponding histologic sections. The cerebrum, cerebellum, brain stem, ventricles, hippocampus, and subarachnoid space were identified and cerebrospinal fluid (CSF) was differentiated from gray matter and white matter on coronal and transaxial magnetic resonance (MR) images.

Osmoregulatory betaine uptake by rat renal medullary slices.

Betaine is an osmolyte present in high concentrations in renal medullary cells. Betaine and other organic osmolytes, such as glycerophosphorylcholine, myo-inositol, and sorbitol, have been shown to increase in concentration during antidiuresis when the inner medullary extracellular osmolality rises. Its concentration may increase in renal cells either by betaine uptake or by choline metabolism to betaine.

Effect of vanadate on renal hypertrophy and sorbitol accumulation in streptozotocin induced diabetes in rats.

Vanadate has been previously shown to normalize blood glucose in streptozotocin-induced diabetic (STZ-DM) rats. The effect of a previously studied dose of vanadate (0.8 mg/ml) in drinking water on blood glucose, renal hypertrophy, and whole kidney polyol accumulation was studied in STZ-DM rats.

Diuretic and natriuretic effects of sorbinil, an aldose reductase inhibitor.

The renal effects of sorbinil, an aldose reductase inhibitor that interferes with the conversion of glucose to sorbitol, were studied in rats and rabbits before and after fluid deprivation. The intracellular osmolar solute, sorbitol, is found in increasing concentrations from cortex to medulla in the kidney and may be involved in the urinary concentrating mechanism. Oral administration of sorbinil in the rabbit resulted in significant increases in urine flow rate and sodium excretion with a tendency toward decreased urine osmolality and increased potassium excretion both before and after water deprivation.

Magnetic resonance imaging and histopathology of hydronephrosis in the rat.

Magnetic resonance imaging revealed conspicuously hyperintense regions in the papillary area of kidneys of three untreated rats. When the kidneys were examined histologically, a hydronephrosis associated with the presence of bacteria was found. This study relates magnetic resonance images of an early stage of hydronephrosis to its histological picture.

Magnetic resonance imaging (MRI) and pathophysiology of the rat kidney in streptozotocin-induced diabetes.

Proton magnetic resonance imaging was performed on rats before induction of diabetes with streptozotocin (STZ) and at 2 and 12 days postinduction. Images revealed an increase in maximal longitudinal and axial dimensions of the kidneys at 2 days and a further increase at 12 days. Similarly, an increase in the size of the remaining kidney was seen in a rat which underwent uninephrectomy as a positive control.

Effect of dimethylaminoethanol, an inhibitor of betaine production, on the disposition of choline in the rat kidney.

The choline metabolite betaine has been shown to be an important organic osmoregulatory solute in the kidney. The isolated perfused rat kidney and kidney slice incubations were used to investigate the effect of 2-dimethylaminoethanol (DMAE), a choline oxidase inhibitor, on the renal excretion and metabolism of choline. In the isolated perfused kidney, [14C]choline, at an initial perfusate concentration of 300 microM, was effectively removed from the perfusate over 25 min, with nearly all the 14C in the perfusate accounted for by betaine during the remainder of the 90-min perfusion.

Excretion and metabolism of nicotinic acid by the avian kidney.

The renal tubular transport and metabolism of nicotinic acid (NA) were investigated using the Sperber technique in unanesthetized hens. Infusion of [14C]NA into the avian renal portal circulation at 10(-10) mol/kg/min revealed that the 14C label was actively transported into urine at a rate 74% that of simultaneously infused tetraethylammonium. Increases in NA infusion rates enhanced 14C label transport so that it eventually equalled the excretion rate of tetraethylammonium.

Effect of acute and chronic hypernatremia on myoinositol and sorbitol concentration in rat brain and kidney.

In animal models of hypernatremia, increases in brain electrolyte content account for the entire increase in osmolality in acute but not chronic hypernatremia, suggesting that there is generation of additional intracellular solutes ("idiogenic osmoles") in chronic hypernatremic states. In the present study, the concentration of the polyols myoinositol and sorbitol and water content were determined in the brain and kidneys of rats made acutely (2 hours) and chronically (72 hours) hypernatremic by intraperitoneal injection of NaCl and water restriction. Both the brain and the kidney responded to chronic hypernatremia with increased levels of myoinositol.

Renal effects of prednisolone in the chicken.

The effects of prednisolone on renal tubular transport of organic ions, urine flow and glomerular filtration rate were studied using the Sperber preparation in chickens. Low infusion rates of 1 and 5 nmole/min prednisolone slightly enhanced organic ion excretion. At higher infusion rates up to 1,000 nmol/min, no change in organic ion transport was observed.

Probenecid inhibition of the renal excretion of dyphylline in chicken, rat and man.

The effect of probenecid on the renal excretion of dyphylline was studied in chicken, rat and man. Dyphylline was found to be actively excreted when measured by the Sperber preparation in hens, the isolated perfused kidney of the rat and clearance studies in man. In each study probenecid significantly decreased dyphylline excretion demonstrating that dyphylline occupied the renal organic anion transport system.

Renal effects of atrial natriuretic factor in domestic fowl.

The renal hemodynamic and tubular effects of ANF were investigated using the Sperber technique in chickens. This technique takes advantage of the unique portal circulation of the avian kidney and permits direct access to the renal peritubular space independent of renal arterial blood flow and glomerular filtration. Infusion of ANF into the avian renal portal system increased urine flow rate and sodium excretion by as much as 300% and 100%, respectively.

Relation between transport maxima and inhibition of organic cation excretion in the chicken kidney.

The ability of several organic cations to inhibit differentially the renal excretion of two prototypical organic cations, tetraethylammonium (TEA) and N1-methylnicotinamide (NMN), was investigated using the Sperber technique in chickens. TEA and NMN excretion were inhibited by the following organic cations in order of decreasing potency: quinine, TEA and NMN. The respective competitive potency of these substances was related inversely to their maximum tubular transport rates (Tm).

Thiazide diuretics inhibit chloride absorption by rabbit distal colon.

In order to investigate the cellular mechanisms of action of thiazide diuretics, the effect of diuretic and nondiuretic thiazide compounds on Cl- absorption across rabbit distal colon was assessed in tissues mounted in Ussing chambers. This epithelium absorbs Cl- via an active electroneutral transport process. Net 36Cl- absorption across short-circuited tissues was decreased 53, 36 and 20% after addition of 10(-4) M trichlormethiazide, bendroflumethiazide or hydrochlorothiazide, respectively, to the mucosal bathing solution.

Renal pressor effect of ethanol in the isolated perfused rat kidney.

These experiments were performed to detect changes in renal function produced by acute infusions of small amounts of ethanol into the isolated kidney of the rat. Ethanol was infused for 10 min beginning at 40 min to reach a final concentration of approximately 80 mg/100 ml in the recirculating perfusate. Control kidneys were perfused for 90 min without the addition of ethanol.

Tubular transport and metabolism of cimetidine in chicken kidneys.

Renal tubular transport and renal metabolism of [14C]cimetidine (CIM) were investigated by unilateral infusion into the renal portal circulation in chickens (Sperber technique). [14C]CIM was actively transported at a rate 88% that of simultaneously infused p-aminohippuric acid, and its transport was saturable. The following organic cations competitively inhibited the tubular transport of [14C]CIM with decreasing potency: CIM, ranitidine, thiamine, procainamide, guanidine and choline.

Effect of renal transplantation on the levels of choline in the plasma of uremic humans.

Plasma choline levels were measured in patients who received a kidney transplant, in donors who underwent nephrectomy and in nonrenal surgical patients. Choline was measured using a choline kinase assay. Choline levels in patients receiving a kidney fell from 29.