A simple, specific, sensitive, and speedy test for glucose in urine has been described. This enzymatic test based on the activity of glucose oxidase and peroxidase is called Clinistix. Data are presented to show that the test has a high accuracy with both positive and negative specimens.

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We evaluated the utility of chloride titrator sticks for facilitating the assessment of dietary salt intake, in a systematic series of clinical trials. These inexpensive devices were applied daily to 24-h or nocturnal urine specimens, thereby avoiding the inter- and intra-subject variability in salt excretion which confounds the use of occasional 24-h urine collections. Chloride and sodium concentrations in urine were highly correlated (r greater than 0.92) in either nocturnal, diurnal, or 24-h collections. The quantitative chloride titrator estimates and measured chloride concentrations were highly correlated as well (r greater than 0.99). The qualitative chloride titrator was graded on a simple scale, and was successfully employed by outpatients attempting to limit their salt intake. Commonly used antihypertensive medications did not interfere with the determinations. Additional chloride intake, such as supplemental potassium chloride, interfered with estimates of salt ingestion, but if the daily amount of potassium chloride supplement was constant, adjustments in interpretation could be made. Renal insufficiency introduced a systematic over-estimation of salt intake by the qualitative chloride tirator, but only at high salt intakes. Relative estimates of salt intake in subjects with renal failure were still possible. We conclude that chloride titrators can facilitate the management of patients who require a prescribed salt intake.

For a long time it has been appreciated that citrate is a constituent of milk and urine. With the development of more accurate and specific methods (1, 2) for the determination of citrate, this ion has been recognized as a constituent of many tissues and body fluids. The occurrence of citrate in the animal body has been reviewed by Smith and Orten (3). Scherst6n (4) has shown that there is quite a large amount of citrate in semen and in the secretion of the seminal vesicles, the concentration in semen being as high as 410 mg. per 100 cc. and in the secretion of the seminal vesicles as much as 633 mg. per 100 gm. which is comparable to the amounts of citrate found in milk and in alkaline urine. These observations have been extended by Huggins and Neal (5) who found in 9 samples of human prostatic fluid, citrate concentrations ranging from 480 to 2688 mg. per 100 cc. Dickens (6) discovered that bone contains a very large amount of citrate, the concentration ranging from 272 mg. per 100 gm. up to as high as 1660 mg. per 100 gm. in dried powdered bone. This investigator isolated both the pentabromoacetone derivative of citric acid and pure citric acid from bone meal. The present report describes studies made of the occurrence of citrate in whole teeth and in separated enamel and dentin. EXPERIMENTAL Twenty sound human teeth of different varieties were cleaned of all organic debris and were dried in an oven at 100°C. These dried teeth were then ground in a steel mortar so that the material had the consistency of a powder. This powder was analyzed for citrate according to the method described below. Three large canine teeth from a dog were treated in a similar manner.To determine citrate on the pooled whole teeth a 50 mg. sample was suspended in 50 cc. of 10% trichloroacetic acid to which 3 cc. of 50% sulfuric acid were added. This mixture was heated to boiling with a resultant solution of the ground tooth powder, and the solution was then analyzed for citrate by the colorimetric method of Pucher, Sherman and Vickery (2).Separation of enamel and dentin was accomplished by the method of Brekhus and Armstrong (7). The separated dentin and enamel were dried and analyzed by the same method used for the whole ground teeth.The results of the citrate analyses on the teeth are summarized in Table I.

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