Accumulation of 6-deoxyerythronolide B in a normal strain of Streptomyces erythreus and hydroxylation at carbon 6 of the erythranolide ring system by a soluble noninduced cell-free enzyme system.

Erythronolide B, a presumed intermediate in the biosynthesis of the erythromycins, has been shown to be formed from 6-deoxyerythronolide B by hydroxylation at C-6. The substrate, a metabolite of a blocked mutant of Streptomyces erythreus and postulated to be an intermediate in the biosynthesis of the erythromycins, is found also in wild-type cultures of S. erythreus CA340 either normally or in increased amount when an inhibitor of NADPH function is present. The hydroxylation of 6-deoxyerythronolide B is catalyzed by a stable and soluble cell-free enzyme preparation obtained from noninduced S. erythreus CA340, and the maximal specific activity of the hydroxylase system is found with the protein fraction precipitating between 50% and 90% of saturation with ammonium sulfate. The hydroxylase activity correlates well with the specific content of a cytochrome P-450 moiety present in the system and is inhibited by anaerobiosis and carbon monoxide.

Experimental inhibition of prostaglandin-like inflammatory response after cryotherapy.

To determine the effect of aspirin as an inhibitor of the prostaglandin-induced inflammatory reaction that follows cryotherapy, 12 rabbits were pretreated with aspirin and 12 were controls. The aspirin-pretreated animals showed less inflammatory reaction after cryotherapy and significantly less protein in the aqueous humor than did the control animals (P less than .01). We believe that the conjunctival hyperemia and chemosis, and the increase in protein concentrations in the aqueous humor that follow cryotherapy, are prostaglandin-related, because pretreatment with aspirin inhibited these phenomena.

Octafluorocyclobutane in vitreous and aqueous humor replacement.

Vitreous replacement with air, pure octafluorocyclobutane (C4F8), and mixtures of 40% C4F8 and 60% air was done in owl monkeys to determine ocular toxicity and duration of gas within the vitreous compartment. Large volumes of gas mixture and pure C4F8 caused posterior subcapsular cataract formation. Pure C4F8 expands in the vitreous within 24 to 48 hours. A 1.0-ml mixture of 40% C4F8 and 60% air lasted 12.7 days and did not cause ocular changes. However, anterior chamber aqueous replacement with pure C4F8 or gas mixture resulted in cataract production. Twenty-four and fourty-eight hours after injection of 0.1-ml pure C4F8 in the vitreous of experimental rabbits, presence of oxygen, nitrogen, and carbon dioxide was shown by gas chromatographic analysis. This finding supports the hypothesis of volume expansion secondary to diffusion of above-mentioned gases inside the C4F8 gas bubble.