Accurate quantization of urea is very essential for precise dialysis therapy in the case of kidney failure. In the present paper we report a new colorimetric method for urea quantification using urease as a probe. The method is based on the reaction between bispyrazolone and ammonia released by the urease catalyzed hydrolysis of urea. A linear relationship of the absorbance at 540 nm of the pro...

Approximately 80,000 blood specimens are submitted to this bureau annually for syphilis serology testing, and it was proposed’ that these specimens be further employed for purposes of diabetic screening. To carry out this type of program, it was desirable to devise a rapid method for the mass determination of glucose levels in blood serum. This paper describes such a method. It is well known th...

This study was aimed to evaluate the antioxidative and urease inhibitory properties of the extracts from Citrullus colocynthis L. The extracts of the root and pulp of fruit were prepared by soxhlet apparatus in methanol as solvent. The antioxidative activities, including DPPH radical scavenging activity, reducing power and total antioxidant activity were studied in vitro. The ...

Reaction of a trinuclear iron(II) complex, Fe3 Br3 L (1), with KC8 under N2 leads to dinitrogen activation products (2) from which Fe3 (NH)3 L (2-1; L is a cyclophane bridged by three β-diketiminate arms) was characterized by X-ray crystallography. (1) H NMR spectra of the protonolysis product of 2 synthesized under (14) N2 and (15) N2 confirm atmospheric N2 reduction, and ammonia is detected b...

The enzymatic method for ammonia with the Du Pont Automatic Clinical Analyzer was tested in our laboratory. The method is very suitable for urine samples although the method was released by Du Pont only for plasma samples. The results correlated well with those obtained by a method based on the Berthelot indophenol reaction and by a method based on the use of an ammonium electrode, which has an...

IN estimating vitamin C chemically in milk by the method of Birch et al. [1933], Kon [1933] observed very marked fluctuations in the concentration of that vitamin from day to day. The possible causes of this phenomenon were investigated by Mattick & Kon [1933], who ultimately found that milk which originally gave a positive vitamin C titration failed to reduce the indophenol reagent after a sho...

The mykotrophic orchid Neottia nidus-avis (L.) Rich. is not able to evolve oxygen in the light. Plastid preparations from the lip (labellum) of the orchid perform a photosystem I-dependent photoreduction of methylviologen with the artificial electron donor couple 2,6-dichlorophenol indophenol ascorbate. Photosystem II reactions such as the ferricyanide Hill reaction or the photoreduction of 2,6...

1. The effect of phosphate on the oxidation of glyceric aldehyde by methylene blue, 1-naphthol 2-sulfonate indophenol, and phenol-indophenol has been studied. 2. At pH 4.77 in a phthalate-buffered medium phosphate does not catalyze the reaction. 3. At pH 7.9 in solutions buffered with borate, carbonate, or phenylalanine marked catalysis by phosphate is observed. The effect is most pronounced in...