tretinoin and thiazolidine-4-carboxylic-acid

Studies have shown that angiotensin-converting enzyme inhibitors and an angiotensin II receptor blocker can delay, but cannot reverse, the progression of experimentally induced radiation nephropathy. In an effort to find a method for reversing injury, three agents were tested in a rat model of radiation nephropathy. Pirfenidone (a phenyl-pyridone antifibrotic) and thiaproline (an inhibitor of collagen deposition) were not capable of retarding the development of radiation nephropathy. However, all-trans retinoic acid (an anti-inflammatory agent) exacerbated radiation nephropathy. We speculated that the detrimental effects of retinoic acid might be the result of stimulation of renal cell proliferation. However, retinoic acid had no effect on tubular or glomerular cell proliferation in normal animals and did not enhance radiation-induced proliferation. A recent report that retinoic acids inhibit nitric oxide production suggested an alternative mechanism, since inhibition of production of nitric oxide is known to exacerbate radiation nephropathy. Experiments demonstrated that retinoic acid exacerbated the radiation-induced drop in renal production of nitric oxide, suggesting that the detrimental effect of all-trans retinoic acid might be explained by inhibition of renal nitric oxide activity. Particularly in view of the recent clinical report of enhancement of radiation nephropathy by retinoic acid in patients receiving bone marrow transplantation, the combination of retinoic acid and renal irradiation should be carried out with great caution.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Division; Extracellular Matrix; Fibrosis; Hypertension, Renal; Kidney; Kidney Diseases; Kidney Failure, Chronic; Proteinuria; Pyridones; Radiation Injuries, Experimental; Rats; Rats, Inbred Strains; Thiazoles; Thiazolidines; Tretinoin; Uremia; Whole-Body Irradiation

The purpose of this paper is to observe the blocking effect of topically subepithelial injected drug and Vit A acid painting on chemically induced oral precancerous lesion and to prove, on a certain extent, the hypothesis that subepithelial connective tissue could exert great influence on the differentiation of the epithelium. A total of 49 syrian hamster was used as experimental animal. Both buccal pouches of all animals were painted thrice weekly with 0.5% DMBA in acetone for 6 weeks. Then, they were divided into two groups: Control group and Experimental group. In the latter group, 70.8% precancerous lesions turned into normal epithelial tissue, whereas those untreated animals developed carcinoma by 62%.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Agents; Cheek; Cricetinae; Epithelium; Injections; Mesocricetus; Mouth Neoplasms; Precancerous Conditions; Thiazoles; Thiazolidines; Tretinoin

Topics: Animals; Antineoplastic Agents; Cricetinae; Drugs, Chinese Herbal; Female; Male; Mesocricetus; Mice; Mice, Inbred BALB C; Mice, Nude; Mouth Mucosa; Mouth Neoplasms; Neoplasm Transplantation; Precancerous Conditions; Thiazoles; Thiazolidines; Tretinoin