Urine volume

Paradoxically, the thia2ides are efficacious, especially if combined with a prostaglandin synthetase inhibitor such as indomethacin or aspirin, in the treatment of nephrogenic diabetes insidipus, in which the patient s renal tubules fail to reabsorb water despite the excessive production of ADH (28). Thia2ides can decrease the urine volume up to 50% in these patients. 

In 20 liters of human urine is dissolved 1,200 grams of sodium benzoate (6% weight by volume). The solution is acidified with aqueous hydrochloric acid (assay about 7.5% HCI) to a pH of 4.5 resulting in a heavy precipitation. This requires 10% of the original urine volume, or about 2 liters of aqueous hydrochloric acid. The suspension is stirred 20 minutes and is then allowed to stand for about 30 minutes. The mixture so obtained is filtered on a Buchner funnel that has been prepared with a precoat of benzoic acid crystals over filter paper. The filter cake is washed with a saturated benzoic acid solution, then sucked dry. The benzoic acid cake with the adsorbed urokinase weighs 2,060 grams. 

Inhibition of V2 vasopressin receptors causes an increase in urine volume primarily by reducing the re-absoiption of water along the collecting duct, an aquaretic effect that is fundamentally different from the natriuretic actions discussed so far. Nevertheless, some of the conditions calling for the use of natriuretic intervention are identical to those in which the administration of a new class of orally active nonpeptide V2 antagonists may be useful (tolvaptan, lixivaptan, and others). 

Direct measurement of creatinine clearance (CrCl) requires collection of urine over an extended time interval (usually 24 hours) with measurement of urine volume, urine creatinine concentration, and serum creatinine concentration (Table 22-1). Because kidney function can fluctuate significantly during ARF, this method may underestimate or overestimate kidney function depending on whether ARF is worsening or resolving. 

Genitourinary Changes in urine volume and consistency, "foaming" of urine (indicative of proteinuria), and sexual dysfunction. 

Increased post-void residual urine volume (more than 50 mL)... 

Post-void residual urine Measurement of urine left in Post-void residual urine volume Post-void residual urine volume greater... 

Postvoid residual urine volume Amount of urine left in the urinary bladder after the patient has been asked to empty the bladder. Assessed by urethral catheterization or ultrasonography. Normal postvoid residual urine volume should be less than 50 mL. An increased postvoid residual urine volume is consistent with incomplete bladder emptying. 

Successive 24-hr urine specimens were provided by each volunteer. Collection in the dosimeter studies began 24 hr prior to the chlorpyrifos exposure (study day 0) and continued for 3 days based upon the 27-hr half-life of chlorpyrifos in humans (Nolan et al., 1984). Pre-exposure controls were obtained in all cases. Total urine volume was measured for each of the days, and 20- to 30-mL portions were stored frozen prior to analysis. The Sacramento collections were 48 hr and the Riverside collections were approximately 84 hr after re-entry. 

The maintenance of plasma volume and plasma osmolarity occurs through regulation of the renal excretion of sodium, chloride, and water. Each of these substances is freely filtered from the glomerulus and reabsorbed from the tubule none is secreted. Because salt and water intake in the diet may vary widely, the renal excretion of these substances is also highly variable. In other words, the kidneys must be able to produce a wide range of urine concentrations and urine volumes. The most dilute urine produced by humans is 65 to 70 mOsm/1 and the most concentrated the urine can be is 1200 mOsm/1 (recall that the plasma osmolarity is 290 mOsm/1). The volume of urine produced per day depends largely upon fluid intake. As fluid intake increases, urine output increases to excrete the excess water. Conversely, as fluid intake decreases or as an individual becomes dehydrated, urine output decreases in order to conserve water. 

The answer is b. (Hardman, pp 695-697.) A significant increase in the amount of any osmotically active solute in voided urine is usually accompanied by an increase in urine volume Osmotic diuretics affect diuresis through this principle. The osmotic diuretics (such as mannitol) are nonelectrolytes that are freely filtered at the glomerulus, undergo limited re absorption by the renal tubules, retain water in the renal tubule, and promote an osmotic diuresis, generally without significant Na excretion. Ln addition, these diuretics resist alteration by metabolic processes. 

Lithium reduces the kidney s ability to concentrate urine and may cause a nephrogenic diabetes insipidus with low urine specific gravity and low osmolality polyuria (urine volume greater than 3 L/day). This may be treated with loop diuretics, thiazide diuretics, or triamterene. If a thiazide diuretic is used, lithium doses should be decreased by 50% and lithium and potassium levels monitored. 

Loop diuretics, particularly when administered by continuous infusion, increase urine volume and renal sodium excretion. Although thiazide... 

Patients with nephrogenic DI should decrease their ECF volume with a thiazide diuretic and dietary sodium restriction (2,000 mg/day), which often decreases urine volume by as much as 50%. Other treatment options include drugs with antidiuretic properties (Table 78-2). 

Peak urinary flow rate <10 mL/s Postvoid residual urine volume >25-50 mL Increased BUN and serum creatinine All of the above signs plus obstructive voiding symptoms and irritative voiding symptoms (signs of detrusor instability)... 

Objective measures of bladder emptying (e.g., uroflowmeter and postvoid residual urine volumes) are also useful after 6 to 12 months of 5a-reductase inhibitor therapy or 3 to 4 weeks of a-adrenergic antagonist therapy. 

Oxybutynin extended-release is better tolerated than oxybutynin IR and is as effective in reducing the number of UI episodes, restoring continence, decreasing the number of micturitions per day, and increasing urine volume voided per micturition. 

Patients with UUI and elevated postvoid residual urine volume should be treated by intermittent self-catheterization along with frequent voiding between catheterizations. 

Blood samples were centrifuged at 1000 x g for 20 min at 0-4°. Ionized calcium levels were immediately determined in serum and urine samples using a calcium ion-selective electrode (Ionetics, Inc., Costa Mesa, CA) urine volumes were recorded. The remaining serum and urine were aliquoted for various analyses and stored at -40°. Serum insulin was analysed by radioimmunoassay (Amersham Corp., Arlington Heights, IL). Serum levels of total calcium, phosphorus and creatinine as well as urine creatinine were determined by colorimetric procedures using an automated analyzer (Centrifichem, Baker Instruments Corp., Pleasantville, NY). Glomerular filtration rates (GFR) were calculated from serum and urine creatinine data GFR = urine creatinine/serum creatinine. 

Weanling female rats were used as the test model in these studies. They were housed individually (10 rats/diet) and offered diet and deionized water ad libitum for 5 months. Apparent calcium and phosphorus absorption and urinary Ca and P losses were measured on collections made the last five days each month. Urine volume and pH values were also recorded. Other data (growth response, serum Ca and P levels, femur mineral composition, femur strength and density, and femur histology) were obtained at the end of the 5-month feeding study. Details of this and the analytical methods used are presented elsewhere (8). All data were subjected to appropriate statistical analyses. 

Urine volume increased steadily during the first three months before levelling off (Table IV). Neither urine volume nor urine pH were significantly affected by the level or type of dietary protein or by their interaction (Tables IV and V). For pH, this could be a masking effect resulting from combining different proteins which individually may appreciably affect urine pH. 

V = urine volume in mL/min (collected usually for 24 hours) Ccr = serum creatinine concentration (mg/dL)... 

Kidney Failure, Acute A clinical syndrome characterized by a sudden decrease in glomerular filtration rate, often to values of less than 1 to 2 ml per minute. It is usually associated with oliguria (urine volumes of less than 400 ml per day) and is always associated with biochemical consequences of the reduction in glomerular filtration rate such as a rise in blood urea nitrogen (BUN) and serum creatinine concentrations. [NIH]... 

By the middle of the nineteenth century it was generally accepted that nitrogen was excreted by mammals as urea, and by 1905 Folin had shown that the amount of urea voided through the kidneys as urine was proportional to the level of protein in the diet. Normally 20-30 g urea are excreted by man per day protein intake also affects urine volume, which is usually 1.2-1.5 L per day. 

Renal Water intake, food intake, body weight, urine volume, urinary excretion of Na, K, Cl Metabolism cage Rat ... 

Other conditions in which ephedra is contraindicated are anxiety disorders, angle-closure glaucoma, prostate adenoma with residual urine volume, pheochromocytoma, and thyrotoxicosis (Gruenwald et al. 1998). Known medications that may interact adversely with ephedrine include heart glycosides, halothane, guanethidine, MAO inhibitors, secale alkaloids, and oxytocin. 

Neonates have diminished nicotine metabolism, as demonstrated by a nicotine half-life of three to four times longer in newborns exposed to tobacco smoke than in adnlts (Dempsey et al. 2000). Cotinine half-life is reported to be similar in neonates, older children, and adults in two studies (Dempsey et al. 2000 Leong et al. 1998). Other studies found that the half-life of urine cotinine was about three times longer in children less than one year old than to the cotinine half-life in adults (Collier et al. 1994). Urine cotinine half-life can be influenced by variations in urine volume and excretion of creatinine. The study by Dempsey et al. was the only one in which the half-life of cotinine was calculated based on both the blood and urine cotinine concentrations (Dempsey et al. 2000). In that study, both the blood and urine half-lives were similar to adult values, supporting the notion that neonates have the same cotinine half-life as older children and adults. 

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