Infection control in dental radiology

Although exposure to blood is rare in oral and maxillofacial radiology, contact with saliva occurs. Thus the spread of infectious diseases is possible through cross-contamination, and specific infection control protocols and unit dosing of items are needed. This article outlines rationale for implementing state-of-the-art infection control procedures; and explains federal standards and guidelines with an impact on infection control and occupational safety in dental radiology procedures.     

The construction and use of nomograms for cerebral blood flow calculation using a 133Xe inhalation technique

Measurement of cerebral blood flow (CBF) using a 133Xe inhalation technique requires monitoring the clearance rate of the radioisotope from the head using externally situated detectors and also from arterial blood using a detector to monitor the expired air activity. The end-tidal concentration function is assumed to be proportional to the arterial concentration function and this has to be deconvoluted from the clearance functions obtained from the head to enable CBF to be calculated. A digital computer is generally considered to be essential for this. In this paper a procedure using three-dimensional nomograms is derived and tested. It is shown that results obtained using the nomograms do not differ significantly from results obtained using a full deconvolution procedure, and so it is not essential to use a computer to calculate CBF by the inhalation technique.     

Sequence and tissue distribution of chicken cellular nucleic acid binding protein cDNA

H+,K+-ATPase preparations from pig stomach were modified with a sulfhydryl fluorescence reagent, N-[p-(2-benzimidazolyl)phenyl] maleimide (BIPM). The addition of ATP to the modified enzyme preparations in the presence of Mg2+ decreased the BIPM fluorescence but increased the Trp fluorescence. After exhaustion of ATP, the fluorescence intensities increased and decreased to the original levels, respectively. The results of stopped flow and rapid quenching experiments suggested that the decrease in BIPM fluorescence (36/s) was accompanied by binding of Mg2+ and ATP or phosphorylation (35 36/s) which was followed by slower increases in Trp fluorescence (24/s) and light scattering (20/s). Tosylphenylalanyl chloromethyl ketone-trypsin treatment of the modified preparations, which showed an about 1% decrease in BIPM fluorescence accompanying phosphorylation, gave one major fluorescent peptide peak on reverse-phase chromatography. Amino acid sequence analysis of the peptide revealed the following sequence, Ser-Pro-Glu-X-Thr-His-Glu-Ser-Pro-Leu-Glu-Thr-Arg. On comparison with the amino acid sequence deduced from cDNA from pig stomach [Maeda, M., Ishizaki, J., and Futai, M. (1988) Biochem. Biophys. Res. Commun. 157, 203-209], X was shown to correspond to Cys241 of the alpha-chain in H+,K+-ATPase. These data and others suggest that the decrease in BIPM fluorescence at Cys241 reflects some molecular event triggered by the binding of ATP with Mg2+ and/or phosphorylation, whereas the increases in the intrinsic Trp fluorescence and light scattering reflect one after phosphorylation.