The recovery of five free ketosteroids, three glucuronides, and six sulfates, added to water or urine and subjected to acid hydrolysis for various lengths of time, was investigated. Dehydroepiandrosterone (DHEA) in all its forms was most susceptible to destruction. The behavior of glucuronides and sulfates differed, and no single set of conditions provided equal recovery for all conjugates. A c...

New, simple and cost effective spectrophotometric methods have been developed for the quality assessment of isoniazid (INH), in bulk and in pharmaceutical formulations by using novel reagents. The proposed methods involve the utility of ethyl 2-[(E)-(4hydroxyphenyl) diazenyl]-3-oxobutanoate and benzil as novel reagents for the determination of INH. Developed methods are based on the condensatio...

The concentration of plant pigments in excreta vs. food provided a measure of digestibility of most plants by grasshoppers. Digestibility values obtained with the chromogen-ratio method and consumption-excretion ratios were highly correlated (r = 0.789**). Greatly disparate results were obtained in 4 cases. The chromogen method, when applicable, gave better duplicability and eliminated many of ...

An automated micromethod for measuring iron concentration in serum employing thioglycollic acid and bathophenantroline sulphonate as reducing agent and chromogen respectively, is described. Measurements are carried out using an AutoAnalyzer (Technicon) and require 0.1 ml of sample. The reproducibility, assessed by the mean coefficient of variation (1.9%), and the mean recovery of iron added to ...

Two simple, sensitive, accurate, rapid, and economical spectrophotometric methods have been developed for the estimation of diacerein in Pharmaceutical dosage forms. Method A is based on the reaction of diacerein with Folin-Ciocalteu reagent, in the presence of 0.5 N sodium hydroxide solution, giving a pink-colored chromogen, which shows maximum absorbance at 512 nm against reagent blank, while...

After a preliminary hydrolysis of the serum samples, the liberated sialic acid is determined by the thiobarbituric acid method of WARREN adapted to the Autoanalyzer. By measuring the developed chromogen in very hot solution, the use of extraction or the addition of stabilizing agents is avoided. Sixty determinations can be run per hour and the optical densities follow a straight line well withi...

A method for the determination of total cholesterol in serum is described. Optimum conditions are found for the isolation of the steroid free from extraneous chromogens, and a new sensitive colour reagent is introduced. The procedure is convenient for routine application, the final colour being light-stable and reasonably time-stable at room temperature. Comparisons are made with one other meth...

We describe a solid-phase enzyme immunoassay for ferritin in human serum, with use of a horseradish peroxidase-labeled antibody and a highly sensitive chromogen, 2,2'-azino-di(3-ethyl-benzthiazoline-6-sulfonate). The assay requires only 10 microL of serum per assay, relatively less time and labor than other assys for ferritin, and as little as 10 pg of ferritin can be measured. We believe this ...

A simple spectrophotometric method is reported her for the estimation of reserpine in polyherbal formulations. Estimation is based on the reaction with3-methylbenzolinone-2hydrazone (MBTH) reagent in presence of cerric ammonium sulphate to yield a violet coloured chromogen, which exhibits and absorption maxima at 580 nm. The chromogen is stable for 10 minutes.

Mike Levine is at the University of California, Berkeley where he is coDirector of the newly formed Center for Integrative Genomics. He obtained his Ph.D. from Yale University with Alan Garen studying steroid-regulated gene expression in Drosophila larvae. As a Jane Coffin Childs fellow he did postdoctoral research with Walter Gehring at the University of Basel in 1982. After a second short pos...