D.W. Russell

Rapid determination of isonicotinic acid hydrazide in whole blood with 2,4,6-trinitrobenzenesulphonic acid

Abstract 1. (1) A spectrophotometric method for the quantitative determination of isonicotinic acid hydrazide (INH) in whole blood is described. 2. (2) The method involves reaction of INH with 2,4,6-trinitrobenzenesulphonic acid and extraction of the coloured product into methyl isobutyl ketone. The absorbance of the extract at 500 nm is proportional to INH concentration up to 30 μg/ml. 3. (3) Streptomycin and known metabolites of INH do not react, but p -amino-salicylic acid should be absent.

The Spore Surface in Pithomyces chartarum

SUMMARY: Crystalline spicules of sporidesmolides, together with some lipid, form the surface layer of spores of Pithomyces chartarum. The formation of the spicules is controlled by the amino acids present in the culture medium.

Simple Method for Determining Isoniazid Acetylator Phenotype

Methods have been developed for estimating acetylisoniazid and isoniazid in urine without a spectrophotometer. In experiments with volunteers the ratio of acetylisoniazid to isoniazid in urine samples collected the morning after three spaced oral doses each of 100 mg. was bimodally distributed.

Low circulating levels of acid-labile hydrazones after oral administration of isonicotinic acid hydrazide

Abstract 1. (1) Hydrazones of isonicotinic acid hydrazide with pyruvic or α-ketoglutaric acid were added to blood. Acidification with trichloroacetic acid liberated the parent hydrazide which was then quantitatively determined by 2,4,6-trmitrobenzenesulphonic acid without interference from other known metabolites of the drug. 2. (2) Trichloroacetic acid treatment of blood, from healthy subjects who had ingested the drug, released isonicotinic acid hydrazide in amounts that were small compared to the amount of the free drug present. These hydrazones can therefore contribute little to the circulating levels of therapeutically active drug.

Determination of branched-chain n-methylamino acids

Abstract Ion-exchange chromatography did not resolve N-methyl-leucine from N-methylisoleucine, and paper chromatography only partially resolved N-methyl-isoleucine from N-methyl-allo-isoleucine. N-Methylvaline was well resolved by both techniques, a combination of which was used to determine all four amino acids quantitatively. A spectrophotometric ninhydrin method is described for determining total branched-chain N-methylamino acids. Primary amino acids, if present, are determined in the same solution with 2,4,6-trinitrobenzenesulphonic acid, with which N-methylamino acids do not react, and a correction is applied to the result of the ninhydrin determination. N-Methyl- d -allo-isoleucine was synthesized and its properties were recorded.

Biosynthetical non-equivalence of the D- and L-valine residues in sporidesmolide I

Abstract Sporidesmolide I, cyclo -Hiv 1 -Val 2 -Me-Leu 3 -Hiv 4 - D -Val 5 - D -Leu 6 , is replaced by its D - a Ile 5 -analogue when the fungus that produces it is grown on media containing L -isoleucine. Even at high isoleucine concentration no detectable replacement of the L -Val 2 residue occurred. When both L -valine and L -isoleucine were present in the medium, the ratio of their concentrations was equal to the ratio D -Val 5 / D - a Ile 5 in the sporidesmolide mixture. It is suggested that two all- L Val-Leu-Hiv chains are synthesized on a multienzyme complex at adjacent sites, only one of which is capable of distinguishing isoleucine from valine; that the chains are cyclized by head-to-tail condensation; and that asymmetry is maintained by continued attachment to the enzyme system during the processes of inversion and methylation.

Determination of isonicotinic acid hydrazide in urine

Abstract 1. (1) The 2,4,6-trinitrobenzenesulphonic acid method for specific determination of isonicotinic acid hydrazide in blood has been modified for use in urine. 2. (2) The modifications include prior semiquantitative determination of isonicotinic acid hydrazide, and its specific oxidation in the sample to provide a control urine which is used to prepare both blanks and standards.