CyberKnife stereotactic radiotherapy for treatment of primary intracranial tumors in dogs.

Background: Limited data exist about the use, efficacy, and prognostic factors influencing outcome when CyberKnife is used to treat dogs with intracranial neoplasia.

Objectives: To determine the prognosis and associated prognostic factors for dogs that were imaged, determined to have primary intracranial tumors, and treated with CyberKnife radiotherapy.

Animals: Fifty-nine dogs treated with CyberKnife radiotherapy for primary intracranial tumors.

Transketolase Activity in the Formation of the Azinomycin Azabicycle Moiety.

The biosynthesis of the azinomycins involves the conversion of glutamic acid to an aziridino[1,2-]pyrrolidine moiety, which together with the epoxide moiety imparts anticancer activity to these agents. The mechanism of azabicycle formation is complex and involves at least 14 enzymatic steps. Previous research has identified -acetyl-glutamate 5-semialdehyde as a key intermediate, which originates from protection of the amino terminus of glutamic acid and subsequent reduction of the γ-carboxylate.

Probing the Role of N-Acetyl-glutamyl 5-Phosphate, an Acyl Phosphate, in the Construction of the Azabicycle Moiety of the Azinomycins.

The azinomycins are potent antitumor agents produced by the soil bacterium Streptomyces sahachiroi and contain a novel aziridino[1,2-a]pyrrolidine core; its synthesis involves at least 14 steps. This study reports the first reconstitution of N-acetylglutamine semialdehyde formation by two enzymes encoded in the azinomycin biosynthetic gene cluster. The reaction proceeds through the formation of an acylphosphate and establishes N-acetyl-glutamyl 5-phosphate and N-acetylglutamine semialdehyde as intermediates in the complex biosynthesis of the aziridino[1,2-a]pyrrolidine moiety.