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Objective-To determine the impact of previous infection with cytomegalovirus, Chlamydia pneumoniae, and Helicobacter pylori on neointimal proliferation after coronary angioplasty with stent implantation. Design-The study population was made up of 180 patients who had stent implantation in a native coronary artery with systematic angiographic and intravascular ultrasound (IVUS) follow up at six months. Quantitative coronary angiography was used to assess the late lumen loss. The mean area of neointimal tissue within the stent and the ratio of neointimal tissue to stent area were assessed from IVUS images. Previous cytomegalovirus, C pneumoniae, and H pylori infection was identified by IgG antibody determination. Results-Previous cytomegalovirus infection was detected in 50% of the population, previous C pneumoniae in 18%, and previous H pylori in 33%. Mean (SD) reference diameter was 2.94 (0.48) mm and mean minimum lumen diameter after stent implantation was 2.45 (0.42) mm. At six months, the mean late loss was 0.74 (0.50) mm, the mean neointimal tissue area was 3.8 (1.7) mm 2 , and the average ratio of neointimal tissue area to stent area was 45 (18)%. None of these variables of restenosis was linked to any of the three infectious agents. By multivariate analysis, lesion length was the variable best correlated with mean neointimal tissue area, the ratio of neointimal tissue to stent area, and late loss, explaining respectively 31%, 39%, and 8% of their variability. Conclusions-Previous infection with cytomegalovirus, C pneumoniae, or H pylori was not a contributing factor in the process of restenosis after stent implantation. (Heart 2001;85:304-311)

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We analyzed the reverse transcriptase (RT) and protease sequences of HIV-1 isolates obtained over 7 years from two couples with known transmission histories. Phylogenetic trees constructed from the sequence data reflected the known transmission histories, despite the fact that the drug resistance mutations were most consistent with the drug treatment histories. However, the RT sequences from one couple diverged by 2.9% even before therapy was begun, and three (0.9%) of 339 unrelated individuals had viruses that shared a common ancestor with sequences from the recipient member of the couple but not with sequences from the transmitter. The divergence between the first two isolates from this couple is consistent with a pretransmission interval during which the transmitter developed a heterogeneous virus population. The closeness between the three controls and the recipient's first RT sequence may indicate slower evolution on the branches of the control sequences. Although the RT and protease genes contain phylogenetic information, they are suboptimal for reconstructing transmission history because the genetic distance between RT and protease isolates from unrelated individuals may occasionally approximate the distance between RT and protease isolates from related individuals.

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