Urine, normal solutes

Definition. A diuretic is any substance which increases urine and solute excretion. This wide definition, however, includes substances not commonly thought of as diuretics, e.g. water. To be therapeutically useful a diuretic should increase the output of sodium as well as of water, since diuretics are normally required to remove oedema fluid, composed of water and solutes, of which sodium is the most important. Diuretics are among the most commonly-used drugs, perhaps because the evolutionary advantages of sodium retention have left an aging population without salt-losing mechanisms of matching efficiency. 

Sample Solutions. The urine sample solutions all originated from one composite urine sample. The latter was made by combining 150-mL aliquots of the entire first-morning voids of 16, presumably healthy, male subjects. Aliquots of the composite were used to prepare three sets of sample solutions as indicated in Table IV. The solutions in each set were "spiked with internal reference elements and with appropriate volumes of multielement stock solution to make a (multiple) standard addition series (12). The final gallium and yttrium internal reference-element concentrations were 1.0 and 0.1 mg/L, respectively, for both the reference and standard addition solutions. The added analyte concentrations for both the reference and standard addition solutions were 0, 2, 4, 10, and 20 times the approximate "normal analyte concentrations for urine, as listed in Table II. 

The metabolic fate of chlordan was studied in rabbits by analysis of the relative chlorine content of chlordan added to normal rabbit s urine and of the chlorine content of the urinary excretory product. The method of analysis was similar to the one previously used (, 4) In addition, hydrolysis of chlordan and of the urinary excretory products was carried out by adding solid sodium hydroxide to saturation to a 10-ml. solution of these substances in hot absolute ethyl alcohol. The mixture was refluxed for 3 hours in a round-bottomed flask immersed in boiling water and the amount of inorganic chlorine determined. Hydrolysis was similarly carried out with solutions of the respective substances in aqueous sodium hydroxide. 

Atrial natriuretic peptide is released from myocardial cells in the atria of the heart in response to an increase in atrial filling, or an increase in plasma volume. This hormone inhibits the release of renin. With less angiotensin Il-induced vasoconstriction of the afferent arteriole, RBF, GFR, and urine output increase. The increased loss of water and solutes decreases blood volume toward normal. 

In 1952 Carsten (Cl) developed a method, which allowed him to isolate and characterize several lower peptides contained in normal and pathological urine. According to this procedure, urine was desalted on the Amberlite IR-100 column and the adsorbed substances washed out with 2 M ammonia solution. The eluate was then passed through the column of Amberlite IRA-400. This column retained the ampholytes and rejected the weak bases. The former were recovered by elution with 1 M hydrochloric acid and the eluate was subsequently fractionated on Dowex 50 resin with 2M and later 4M hydrochloric acid as the eluents. By applying two-dimensional paper chromatography to further analysis of... 

In 1978, on the basis of a few measurements of urine calcium and phosphate excretion as well as an awareness of the previously mentioned work regarding the amounts of calcium and phosphate normally accreted in utero and postnatally, it became apparent that the demineralization, fractures and rickets we were seeing in our infants were caused by calcium deficiency. Consequently we increased the amount of calcium added to the parenteral alimentation solutions. If more than 12.5 mM of the calcium were added to a liter of hyperalimentation solution, gross precipitation would occur in the feeding solution. If 10 mM of calcium were added per liter, crystalline precipitated began to build up on the inside of our barium-impregnated silicone rubber central venous catheters. This crystalline precipitate resulted in gradual occlusion and functional loss of these lines. After several false starts and six lost catheters, chemical and crystal analysis showed that the precipitate inside these catheters was CaHPO. ... 

Many animal species excrete more calcium if fed an acid or acidforming compounds. In the calf, Steenbock and coworkers (13) observed hypercalciuria and acidic urine after feeding hydrochloric acid to the calf. Stehle (14) pointed out that calcium represented the main long-term fixed base to be lost in the urine of the dog loaded with excessive amounts of hydrochloric acid. Walzer and Browder (15) demonstrated that when infused with a sulfate containing solution, the dog excreted several fold more acid and calcium than saline-infused controls the increased calcium loss returned to normal upon removal of the sulfate. Marone, et al. (16) demonstrated increased excretion of calcium in the acidotic dog. Correction of the acidosis reduced the excessive fractional calcium excretion rate, but did not alter sodium excretion. 

In the only study that measured 1,3-DNB metabolite production in humans after dermal exposure, the total production of both amino and nitro metabolites in urine was reported using 2,4-dinitrophenol as a standard (Ishihara et al. 1976). The results indicate that 1,3-DNB (in solution) rapidly penetrated skin and was also rapidly converted and excreted in urine. A maximum amount of amino and nitro metabolites was reached within the first hour after exposure and returned to normal levels after 10 hours. The limitations of this study are a small sample size (one person) and no detailed information on the nature of 1,3-DNB metabolites. 

QUANTITATIVE ASPECTS. Normally the presence of high quantities of the organic acid is sufficient for diagnosis. However, quantification is sometimes required. To do this, serial amounts of the individual acid must be carried through the derivatization, and a calibration curve set up. The various acids show widely different responses to the argon detector. From the standard curves the amounts can be derived by interpolation. Calculation on the basis of urine dilution must be included as well as the aliquot of the final solution that was taken for injection. The procedure for this is similar to that described for estriol in pregnancy urine. 

The use of povidone-iodine for the treatment of burns, for peritoneal lavage in the treatment of purulent peritonitis, or as a rinsing solution for body cavities can increase serum iodine concentrations associated with increased urinary excretion of iodine. In people with burns the extent of iodine absorption depends on the extent of the burned body surface. It is not uncommon for serum iodine concentrations to rise to more than 1000 pg/ml. If renal function is intact, iodine elimination in the urine can be adequate. The serum iodine concentration returns to normal about 1 week after the last application. 

In the kidney, filtered solutes such as glucose are recovered from the forming urine primarily by active transport mechanisms in the renal tubules. As in the small intestine, glucose is removed from the tubule lumen by SGLT1 and exits across the basolateral membrane via GLUT2. The low affinity of GLUT2 makes flow from the blood into the tubule epithelial cells minimal at normal blood glucose concen-... 

The specific gravity of normal urine may range from 1.008 to 1.030. After excessive fluid intake (like a beer party), the specific gravity may be on the low side after heavy exercise and perspiration, it may be on the high side. High specific gravity indicates excessive dissolved solutes in the urine. 

Peter et al. [15] used an electrically heated quartz cell for the determination of arsenic in urine. Urine, 2 ml, was digested with 2 ml of nitric and perchloric acids (1 1). Aliquots of this solution were used for the subsequent arsine generation by sodium borohydride. The normal level of arsenic in urine was found to be less than lOppb. 

The preferred sample for this analysis is stomach contents, since the quantities of drug present are normally higher than in a urine sample. Urine can be used, but a concomitant analysis by thin-layer chromatography is advisable. The extract from stomach contents or urine is examined on two independent columns using 2.5% SE-30 on Chromo-sorb G (System GA, p. 192), and 3% Poly A103 on Chromosorb W HP (System GF, p. 195). Compounds are identified by reference to retention data derived by chromatographing a solution of pure drugs in chloroform. 

Reference Solution. Prepare a solution containing 10 p-g/ml of bendrofluazide, chlorothiazide, and frusemide in normal urine. 

Identification of Salicylic Acid in Horse Urine No statutory limit is prescribed for salicylic acid, but it is normally present in horse urine it is important, therefore, to distinguish between normal concentrations and those arising from medication with aspirin or other salicylates such as topically applied methyl salicylate. Normal urine concentrations rarely exceed 10 LLg/ml, but therapeutic doses of aspirin may give concentrations as much as 500 times greater. Addition of 1 ml of freshly prepared ferric chloride solution to 5 ml of urine will give a detectable violet colour when the concentration of salicylic acid exceeds about 100 ig/ml. A positive result should be followed... 

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