Sudden cardiac death risk was low (0.02%/patient-year) in this WPW population. The SVT incidence was 1% per patient-year. Referral bias and some characteristics of the unique military aviator population may partly account for these low event rates. However, these results may be more applicable to unselected populations than are tertiary referral-based studies.

We have used the heterobifunctional reagent (4-azidophenyl)glyoxal (APG) to cross-link RNA to protein in Escherichia coli 30S ribosomal subunits. Synthesis and characterization of the reagent are described. Like other dicarbonyl reagents (e.g., kethoxal), APG reacts specifically with guanosine among the four ribonucleosides. The azido group in APG can be photolyzed with UV light (lambda greater than 300 nm), yielding an unstable nitrene which is potentially reactive with many groups in proteins and nucleic acids. Conditions for APG modification of guanylic acid residues in 30S subunits are described; photolysis of bound APG results in cross-linking of approximately 5% of the total 30S proteins to 16S RNA. A specific subset of the 30S proteins is cross-linked to 16S RNA by APG.

Detection of Salmonella typhi in blood by culture of the mononuclear cell-platelet layer was compared with other methods currently used for the diagnosis of typhoid fever. Colonies of S. typhi were present in all mononuclear cell-platelet layer-positive cultures within 18 h of plating and were identified within an additional 10 min by a coagglutination technique. In contrast, identification of all positive cultures by conventional blood culture required 3 days.

DNA probe was used to detect Salmonella typhi from blood samples from 14 of 33 patients with culture-confirmed typhoid fever, using the equivalent of 2.5 ml of blood. In contrast, S. typhi was detected in 17 of the same 33 patients by culture of 8 ml of blood. The probe hybridized to blood samples of 4 of 47 patients from whom S. typhi was not isolated.