Multifocal skeletal tuberculosis involving the lumbar spine and iliac bone, mimicking a malignant bone tumour: a case report.

ABSTRACT: Multifocal osteoarticular tuberculosis is uncommon and accounts for approximately10% of all cases of osteoarticular tuberculosis. Concomitant vertebral and iliac bone tuberculosis has not been reported in the literature to date. We report one such case for its unusual clinical and radiological presentation, which had presentation more similar to a malignant bone tumour than an infection. KEY WORDS: Skeletal tuberculosis, multifocal osteoarticular tuberculosis.

Multifocal Skeletal Tuberculosis Involving the Lumbar Spine and Iliac Bone, Mimicking a Malignant Bone Tumour: A Case Report

Multifocal osteoarticular tuberculosis is uncommon and accounts for approximately10% of all cases of osteoarticular tuberculosis. Concomitant vertebral and iliac bone tuberculosis has not been reported in the literature to date. We report one such case for its unusual clinical and radiological presentation, which had presentation more similar to a malignant bone tumour than an infection.

Screening for sarin in air and water by solid-phase microextraction-gas chromatography-mass spectrometry.

A method of screening air and water samples for the chemical-warfare agent Sarin is developed using solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS). The SPME field kit sampler is ideal for collecting air and water samples in the field and transporting samples safely to the laboratory. The sampler also allows the sample to be introduced into the GC-MS system without further sample preparation. Results of the tests with Sarin using the SPME technique indicate that a sample collection time of 5 min is sufficient to detect 100 ng/L of Sarin in air. For water samples, Sarin is detected at a concentration of 12 microg/mL or higher. This method is ideal for screening samples for quick response situations.

Isolation of a highly mutagenic aminophenanthrene from a coal gasification process tar.

A major portion of the mutagenic activity associated with products and by-products of coal conversion can be ascribed to nitrogen-containing bases. We improved the extraction efficiencies for three- to five-ring aromatic bases by extracting them with a mixture of methanol and aqueous HCl, rather than with aqueous HCl alone. A complex mutagenic basic fraction of a coal gasification process tar was successively fractionated using cation exchange and reversed phase high-performance liquid chromatography. The fractions were assayed for mutagenic activity and were chemically analyzed by gas chromatography and gas chromatography-mass spectrometry. Aminophenanthrenes were identified as major contributors to the mutagenicity of the basic fraction. Aminonaphthalenes, aminobiphenyls, and their alkyl homologs were also present but were not detected as principal mutagens.

Alphatic 3,4-epoxyalcohols. Metabolism by epoxide hydrase and mutagenic activity.

Rabbit hepatic microsomal epoxide hydrase catalyzes the rapid hydrolysis of 1,2-epoxy-4-heptanol to 1,2,4-heptanetriol. Both diastereomers of the substrate are hydrolyzed, and both product diastereomers are formed. Similarly both cis- and trans-3,4-epoxy-1-hexanol are hydrolyzed, albeit more slowly, to give 1,3,4-hexanetriol. The trans isomer gives exclusively one diastereomer (erythro) of the triol, while the cis isomer gives the other diastereomer (threo). The product expected if a primary cationic intermediate were to be formed and trapped intramolecularly during the hydrolysis of 1,2-epoxy-4-heptanol, 2-propyl-4-tetrahydrofuranol, was not observed. A comparison of the mutagenic activity in the Ames test of 1-heptane, 1-hepten-4-ol, 1,2-epoxyheptane, and 1,2-epoxy-4-heptanol revealed that only the latter is a detectable mutagen. A vicinal hydroxyl therefore does not interfere significantly with enzymatic epoxide hydrolysis, but it does enhance the bioalkylating potential of even an aliphatic epoxide.

Substrate selectivity of squalene synthetase.

Six 1-3H-labeled analogues of farnesyl pyrophosphate have been studied as potential substrates for yeast and rat liver squalene synthetases: 2-methylfarnesyl pyrophosphate (4), 3-demethylfarnesyl pyrophosphate (5), 7,11-dimethyl-3-ethyl-2,6,10-dodecatrienyl pyrophosphate (6), 6,7,10,11-tetrahydrofarnesyl pyrophosphate (7), 4-methylthiofarnesyl pyrophosphate (8), and 4-fluorofarnesyl pyrophosphate (9). Analogues 4 and 5 are enzymatically incorporated into 11-methylsqualene (10) and 10-demethylsqualene (11), respectively, even if no farnesyl pyrophosphate is added to the incubations. None of the other analogues gives nonpolar products with either the yeast or liver enzymes. No tritium is enzymatically released to the medium from any of the analogues, indicating that they are not accepted at the first (proton exchanging) site. The data rule out formation of dead-end presqualene pyrophosphate products with analogues as first, but not as second, substrates. Implications of these results for the enzyme active-site topology and mechanism are discussed.

Inhibition of squalene synthetase by farnesyl pyrophosphate analogues.

The pyrophosphates of the following farnesol analogues have been synthesized: 2-methylfarnesol; 7,11-dimethyl-3-ethyl-2,6,10-dodecatrien-1-ol; 3-demethylfarnesol; 4-methylthiofarnesol; 7,11-dimethyl-3-iodo-2,6,10-dodecatrien-1-ol; 7,11-dimethyl02-iodo-2,6,10-dodecatrien-1-ol; 7,11-dimethyldodeca-6,10-dien-2-yn-1-ol; phytol; 3,7,11-trimethyl-2-dodecen-1-ol; 3,7,11-trimethyldodecan-1-ol; and geraniol. The double bonds in all the above compounds were in the E configuration, except phytol, which was a 7:3 mixture of 2E and 2Z isomers. Each of the pyrophosphates inhibits the incorporation of labeled farnesyl pyrophosphate into squalene by a yeast enzyme preparation. Free alcohols and monophosphates are inactive. The analogues, listed in order of decreasing inhibitory strength, are, by kinetic analysis, competitive or mixed inhibitors. Irreversible inhibition is not observed. The results suggest that binding to the enzyme is primarily mediated by the pyrophosphate moiety assisted by relatively nonspecific lipophilic interactions. Decreasing the chain length and saturating double bonds severely reduces binding, while substitution at the 2,3, and 4 positions, and lengthening of the chain, is well tolerated.