Substrates for ribosomal peptidyl transferase: synthesis of 3'-N-aminoacyl and 5'-O-nucleotidyl analogues of puromycin

The chemical synthesis, on a 10–30 μmol scale, of two series of puromycin analogues is described: the first is the type 3′-N-aminoacyl-puromycin aminonucleoside (e.g. 3′-N-glycyl-PANS or PANS-Gly) in which the O-methyl-L-tyrosyl residue of puromycin is replaced by various aminoacyl residues, and the second is the type NpPANS-Gly in which the 5′-hydroxyl of PANS-Gly is substituted with phosphate, 3′-AMP, 3′-CMP, 3′-GMP, or 3′-UMP. The 3′-N-aminoacyl-PANS derivatives were synthesized either by coupling N-protected amino acids via their N-hydroxysuccinimide esters to PANS in 70% aqueous pyridine or by direct coupling in ethanol or methanol of N-protected amino acids to PANS using N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) as condensing agent After removal of the protecting groups, reaction mixtures were purified by preparative thin-layer chromatography on silicic acid, paper chromatography, and paper electrophoresis to give the 3′-N-aminoacyl-PANS derivatives in yields of 40–80%.The 5′-O-nucleotidyl derivatives of PANS-Gly were synthesized by three methods: (i) by the coupling of fully acetylated 3′-mononucleotides to 3′-N-(Boc-glycyl)-PANS, (ii) by the coupling of N4-acetyl-2′,5′-di-O-tetrahydropyranylcytidine or N2,O2′,O5′-tritetrahydropyranylguanosine to 5′-O-phosphoryl-(Boc-glycyl)-PANS, and (iii) by the coupling of N4-acetyl-2′,5′-di-O-tetrahydropyranyl-3′-CMP or N2,O2′,O5′-tritetrahydropyranyl-3′-GMP to 3′-N-Boc-PANS or 3′-N-trifluoroacetyl-PANS followed by aminoacylation of the CpPANS or GpPANS produced with Boc-glycine and EEDQ. Coupling reactions were carried out using either N,N′-dicyclohexylcarbodiimide or 2,4,6-triisopropylbenzenesulfonyl chloride as condensing agents in anhydrous pyridine. After removal of protecting groups, reaction mixtures were purified by paper chromatography and paper electrophoresis to give the NpPANS-Gly derivatives in 3–30% yield.

MMPI scales vs interviewer ratings of paranoia

Three sub-scales of the MMPI ( Sc, Pa, and Stein's recently devised Suspicion scale) had low positive correlations with two interview-derived indices of paranoia in a sample of 44 patients who had been classified by the staffs of their wards as either clearly paranoid or clearly non-paranoid.

Holographic subsonic flow visualization

A pulsed ruby laser holographic interferometer was used to detect density gradients in the airflow around an airfoil at subsonic speeds in a low speed wind tunnel. These experiments proved that vibration of the optical components or object between exposures of the interferometric hologram does not destroy the detection of density gradients but actually can aid in the flow visualization. The density gradients determined from the fringe pattern analysis are consistent with the anticipated flow pattern.

Production of lung carcinomas in C57BL mice exposed to a cigarette smoke and air mixture

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Contaminant viruses in two live virus vaccines produced in chick cells

Samples of yellow-fever vaccine prepared from homogenized chick embryos, and of an experimental measles vaccine prepared from chick embryo cells, have each been shown to contain a contaminant virus similar in properties to an avian leukosis virus. Young adult males injected with the yellow-fever vaccine did not develop neutralizing antibodies for Rous sarcoma virus.

Organ donation terminology: are we communicating life or death?

The continued functioning of organ transplantation depends on obtaining the permission of the next of kin. This communication process between medical or transplant professionals and a donor family hinges heavily on the understanding of certain critical terms like brain dead, life support, and transplantation. Communication issues in obtaining organ donation consent were examined, with particular focus on what are literally life-and-death decisions. Using an experimental simulation methodology, data are offered in support of the claim that much miscommunication occurs in such situations. Directions for improving such communication by allaying latent fears and more carefully defining crucial terminology are offered.