Thalidomide: a re-look.

Thalidomide was synthesized in 1954 in erstwhile West Germany and marketed as a sedative in over 46 countries until the early 1960s. Owing to serious teratogenic effects, the drug was withdrawn from the market in 1961. A chance observation suggested the utility of thalidomide in erythema nodosum leprosum (ENL). After many controlled and uncontrolled trials were published, the World Health Organization recommended its use in ENL. The Food and Drug Administration, USA approved it for use in ENL in July 1998. Only established and well-defined studies conducted to substantiate the efficacy of thalidomide have been included in this review. Thalidomide is considered the drug of choice for the treatment of ENL, but for other conditions, it is recommended only when resistance to the currently available form of therapy is encountered. Once the anti-inflammatory, immuno-modulatory, anti-TNF-alpha and anti-angiogenic properties of thalidomide were discovered, it was also tried in AIDS and related wasting, apthous ulcers, microsporidiosis and Kaposi's sarcoma. Thalidomide has no clinical place as an immunosuppressant in solid organ transplantation. However, it has a therapeutic role in graft-verus-host-disease. Among the dermatological conditions, thalidomide has been found to be effective in systemic lupus erythematosus, discoid lupus erythematosus, actinic prurigo and prurigo nodularis. Used correctly, it is a safe and effective medicine (except for its teratogenic potential and delayed neuropathy) in a variety of disease conditions.

Arginase from rat fibrosarcoma. Its possible role in proline, glutamate and polyamine metabolism.

The presence of arginase in rat fibrosarcoma not synthesizing urea, suggested that this enzyme may have additional functions. Ornithine carbamoyl transferase, a key enzyme of the urea cycle was absent in this tissue, when compared to normal tissues, lower amount of ornithine was found in the fibrosarcoma, but this tumour contained a higher level of proline. The radioactivity present in L-[U-14C] arginine was incorporated into putrescine, spermidine, spermine, proline glutamate and glutamine suggesting that arginine was a possible precursor and that arginase may have a role in the synthesis of these metabolites.

Argi nase from rat fibrosarcoma. Purification and properties.

Arginase from rat fibrosarcoma was purified about 1900-fold and its properties were compared with those of the enzyme from liver and kidney. Arginase from fibrosarcoma was a neutral protein of molecular weight 120,000 with a Km value of 11 mM for arginine. The activation energy was 7.2 kcal/mol and the pH optimum was 10. The fibrosarcoma enzyme was immunologically different from that of the liver. The arginase from fibrosarcoma closely resembled the arginase from the kidney in its electrophoretic, kinetic and immunological properties.