The discovery of aminoglycoside 66-40C, a novel dimeric, unsaturated imine produced by Micromonospora inyoensis, afforded a versatile intermediate for the synthesis of a variety of sisomicin analogues modified at the 6' position. The conversion of 66-40C into sisomicin, antibiotic G-52, and a series of novel 6'-substituted analogues of sisomicin is described, and the biological activity of the products is discussed.

Antibiotic G-418 was shown to be superior to paromomycin and metronidazole in cecal amoebiasis. Of particular interest was the high degree of activity seen with a relatively short treatment at low levels. Although the antibiotic was trichomonacidal in vitro at low levels, in vivo results indicated that at levels tested the antibiotic did not always affect cures. The antibiotic appears to have promise as an anticestode agent, being more active than paromomycin against Hymenolepis nana and active as a single oral dose at low levels against Taenia spp.

The physiological effects of high-intensity x-irradiation (2 x 105 r/min.) and dosages of 1 x 106 r on mice (head and abdomen) were investigated. An increase in pulmonary and heart rates were observed. Electrocardiographic recordings after irradiation demonstrated reversal of wave components and increase of amplitudes. Blood counts present no changes except for a drop in leukocyte counts. Hemoglobin remained unchanged. A considerable increase in serum potassium was noted and some indications of methemoglobin production. Head-irradiated animals yielded a higher incidence of auricular congestion and brain hemorrhage in contrast to animals receiving abdominal irradiation.

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Aufgrund der antibiotischen Wirkung von Sisomicin (IVa) und dem Antibioticum G‐52 (IVb) werden nach bekannten Verfahren der Zuckerchemie zahlreiche weitere ähnliche Verbindungen, z.B. der Formeln (I)‐(III) sowie (IVc)‐(IVh), hergestellt und untersucht.