Detection of the Human Cytomegalovirus 2.0-kb Immediate Early Gene 1 Transcripts in Permissive and Nonpermissive Infections by RNA in situ Hybridization.

The immediate early gene 1 (IE1) is the first gene to be expressed following the entry of the human cytomegalovirus (HCMV) into the cell and it does not require prior protein synthesis for its expression. Therefore, the IE1 gene is a potential candidate for the development of probes to detect HCMV in various states of infection. Using strand-specific (32)P- or digoxigenin-labeled riboprobes derived from an exon-specific subgenomic fragment of the HCMV Towne IE1 gene, we performed Northern blot analysis and RNA in situ hybridization on HCMV-infected human (permissive cells) and mouse (nonpermissive cells) fibroblasts and on 10 formalin-fixed paraffin-embedded sections of human tissue. By Northern blot analysis and by in situ hybridization, expression of the 2.0-kb IE1 gene was found in permissive as well as in nonpermissive infections. Specific nuclear and cytoplasmic hybridization was found at 5, 10, 24 and 72 h after infection in human fibroblasts. In comparison, hybridization was first detected at 10 h after infection in mouse fibroblasts. Hybridization with the IE1 probe was detected in cells with and without cytopathic changes in the formalin-fixed paraffin-embedded HCMV-infected human tissues. Hybridization patterns of the IE1 riboprobe were compared to those of the HCMV 2.7-kb major early beta-riboprobe which we have previously described [Am J Pathol 141:1247-1254;1992]. Although both riboprobes hybridize to their respective target sequences in the consecutive tissue sections, the patterns of hybridization are different. On occasion, sections of HCMV-infected human tissue showing no specific hybridization for the 2.7-kb riboprobe will show specific in situ hybridization when using the IE1 riboprobe. Our results suggest that RNA in situ hybridization with a probe directed at the IE1 transcripts is an effective method of detecting early and late stages of both permissive and nonpermissive HCMV infections. Copyright 1997 S. Karger AG, Basel

Cervical spine trauma: how much more do we learn by routinely using helical CT?

Assessment of suspected cervical spine injuries remains a major debate in trauma care. It is generally accepted that many fractures are missed or incompletely shown at radiography, mainly because of suboptimal studies obtained in obtunded, uncooperative trauma victims. In a series of 88 severely traumatized patients, the authors retrospectively determined the type, distribution, and significance of such missed lesions. This assessment was made by comparing radiographs and helical computed tomographic (CT) scans of the cervical spine and reviewing medical records in these cases. Of the 88 patients, 32 patients had cervical spine fractures (n = 50) that were not revealed or were incompletely demonstrated at radiography. Most missed fractures occurred at the C-1 to C-2 and C-6 to C-7 levels, and most involved the transverse processes and the posterolateral elements of the vertebrae. One-third of the patients with missed fractures had either clinically significant or unstable injuries, as determined on the basis of mechanistic or imaging criteria. Helical CT can depict significant fractures not shown by plain radiography and should be added routinely to the initial screening for cervical spine fractures in polytrauma victims.