ブレオマイシン

解説Streptomyces verticillusの生産する抗生物質．Fe(II)と酸素と複合体を形成したブレオマイシンは，還元によってブレオマイシン-Fe(III)-HO2－型となって活性化され，一本鎖DNAを切断する．ブレオマイシンを投与したマウスでは皮膚で高いブレオマイシン濃度が観察されるが，これは他の臓器に比べてブレオマイシンが皮膚で分解されにくいからである．このため，ブレオマイシンはとくに扁平上皮がんに対して有効な制がん剤である．

用途ブレオマイシン系抗生物質DNA合成阻害およびDNA鎖切断により抗がん作用を示す

説明Bleomycin is a complex of no less than 16 glycopeptide antibiotics made from the family Streptomyces verticilus, which have different R groups. Bleomycines exhibit antitumor, antiviral, and antibacterial activity. When bound to DNA, they disturb the spiraling of both single and double strands of DNA. To a lesser degree, they inhibit RNA and protein synthesis. It is administered both intravenously and intramuscularly.

使用Bleomycin sulfate USP (Blenoxane)is used to traet squamous cell carcinoma of head, neck, esophagus, skin, GU tract; testicular tumor; Hodgkin’s lymphomas.

一般的な説明Bleomycin is a glycopeptide antibiotic complex isolatedfrom Streptomyces verticillus initially by Umezawa.Atleast 13 different fractions of bleomycin have been isolatedwith the clinically used product (Blenoxane) being a mixtureof predominantly A22 (55%–70%) and B2 (25%–32%)fractions.Of these fractions, A2 appears to possessthe greatest antineoplastic activity. Copper is found inthe naturally occurring material, and its removal is importantfor the material used clinically because it significantlyreduces activity.Bleomycin is notable for its lack of myelotoxicity, andthis allows it to be combined with other myelosuppressantswithout a resulting additive effect. The acute toxicities seenwith bleomycin are erythema (reddening of the skin), hyperpigmentation(skin darkening) found predominately on theextremities, and pulmonary toxicity. The pulmonary toxicitymay first occur as pneumonitis (inflammation of lung tissue),which normally responds to glucocorticosteroid therapy.Chronic pulmonary toxicity is expressed as pulmonaryfibrosis, which is irreversible and limits utility of the agent.