BACKGROUND Salivary alpha-amylase (sAA) is considered a biomarker of sympathetic activation in humans, but there is controversy regarding the existence of sAA in dogs. The hypothesis of this study was that sAA exists in dogs and it could change in situations of sympathetic stimulation. Therefore, the aims of this study were: 1) to demonstrate the presence of alpha-amylase in saliva of dogs by W...

Spectrophotometry is an analytical technique of increasing importance for the food industry, applied i.a. in the quantitative assessment of the composition of mixtures. Since the absorbance data acquired by means of a spectrophotometer are highly correlated, the problem of calibration of a spectrophotometric analyzer is, as a rule, numerically ill-conditioned, and advanced data-processing metho...

BECAUSE OF VARIATION in hemoglobin concentration in normal bloods with age and sex (1), the per cent carbon monoxide saturation of hemoglobin represents a more accurate toxicity index than the volume per cent of carbon monoxide. In 2 of the most common methods of carbon monoxide determination in blood, the gasometric method of Van Slyke (2, 3, 4) and the spectrophotometric method of Harper (5),...

A sensitive and specific automatic bioluminescent method is described for glucose determination in serum samples using commercially available reagent-kits. The Boehringer Gluco-quant kit, originally designed for spectrophotometric measurement, was successfully coupled to the bacterial luciferase NAD(P)H-linked system. The method's validity was proven by comparison with a spectrophotometric meth...

A simple spectrophotometric system, based on a prolonged pseudo-liquid drop device as an optical cell and a handheld charge coupled device (CCD) as a detector, was constructed for automatic liquid-liquid extraction and spectrophotometric speciation of trace Cr(VI) and Cr(III) in water samples. A tungsten halogen lamp was used as the light source, and a laboratory-constructed T-tube with two ope...

Medium or high charge density cationic polyelectrolytes are frequently used for water treatment. In the papermaking wet-end they are used as retention agents or as flocculating aids. Negative polyelectrolytes that enter the papermaking system increase the demand for cationic polyelectrolytes. Polyelectrolyte concentration can be determined by the colloidal titration method, using either of two ...

Spectrophotometry is an analytical technique of increasing importance for the food industry, applied i.a. in the quantitative assessment of the composition of mixtures. Since the absorbance data acquired by means of a spectrophotometer are highly correlated, the problem of calibration of a spectrophotometric analyzer is, as a rule, numerically ill-conditioned, and advanced data-processing metho...

Methods of directly evaluating cyanide levels are limited by the volatility of cyanide and by the difficulty of establishing steady-state cyanide levels with time. We investigated the measurement of a stable, toxic metabolite, 2-aminothiazoline-4-carboxylic acid (ATCA), in an attempt to circumvent the challenge of directly determining cyanide concentrations in aqueous media. This study was focu...

Several researchers have proposed spectrophotometric modifications of the Winkler titrimetric method for measuring dissolved oxygen (DO). These modifications, although simple, are not widely used because of concern about accuracy, calibration, and possible sources of interference. Here we show, using natural samples from lakes and rivers as well as samples manipulated in the laboratory, that th...

In mitochondria-enriched preparations of human skeletal muscle, the measurement of pyruvate dehydrogenase activity, as determined by conventional spectrophotometric assay of NADH accumulation, is underestimated due to the oxidizing activity of the contaminating lactate dehydrogenase. Using a model reaction system consisting of varying mixtures of purified lactate and pyruvate dehydrogenases, we...