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Although recent studies have shown that adhesion molecules on alveolar macrophages are important in a variety of pulmonary diseases, there have been few studies on the phenotypic and functional changes of alveolar macrophages during cardiopulmonary bypass. To investigate the possible role of alveolar macrophages in activating pulmonary immunity during cardiopulmonary bypass, we measured the expression of adhesion molecules on alveolar macrophages and peripheral blood monocytes in patients undergoing cardiopulmonary bypass. Antigens were stained with monoclonal antibodies against adhesion molecules, and the expression of antigens was quantified by flow cytometry as the ratio of specific to nonspecific linear fluorescence. On alveolar macrophages obtained after the release of aortic cross-clamp, macrophages as compared with alveolar macrophages obtained before cardiopulmonary bypass, there was a significant enhancement of CD11a, CD11b, CD11c, and CD18. In addition, alveolar macrophages, but not peripheral monocytes, produced higher levels of TNF-alpha and IL-8 when they were cultured in vitro. A higher expression of CD11 and CD18 on alveolar macrophages and enhanced production of cytokines after release of the aortic cross-clamp may contribute to immune activation in lung by macrophage-lymphocyte interaction.

Background and Purpose-Transcranial Doppler ultrasound (TCD) can detect circulating microembolic signals (MES). We focused our attention on tail signs (TS), a signal associated with MES that appeared as a small reversal signal after MES on the high time resolution spectral display. We examined MES and artifacts in an animal study to determine whether TS were specific changes associated with MES and investigated the characteristics of TS in both animal and clinical studies. Methods-In an animal study, adult pigs with venoarterial extracorporeal membrane oxygenation and minimal anticoagulation therapy were used as a model for cerebral embolism. After performing TCD monitoring with a multigated approach, we did an offline analysis to investigate several parameters concerning MES and TS. We also examined TS in patients in a clinical study. Results-From a total of 362 MES investigated in the animal study, 72.9% were followed by TS. We could not find any TS associated with artifacts. The time delay between TS and MES was negatively correlated with the velocity of MES. MES almost always appeared first in the proximal channel, whereas TS conversely appeared first in the distal channel.In the clinical study, we were also able to observe TS associated with MES. C erebral microembolic signals (MES) were first described during carotid surgeries. 1 Transcranial Doppler ultrasound (TCD) has been reported 2,3 to be capable of detecting circulating cerebral MES in patients with ischemic stroke. Most common identification criteria for MES are based on the basic audiovisual characteristics of high-intensity transient signals. 4 Applying this technique to clinical practice, it is not always easy to differentiate true embolic signals from artifact. Spontaneous speckling in the background signal makes differentiation even more difficult. Automated detection software including neural network 5 or multigate approach 6 systems have been developed recently. Although the differentiation between MES and artifact is, in principle, possible with these methods, they are all dependent on different methodological limitations. The optimal recording time of TCD monitoring remains undetermined. 7 If the prevalence of MES is too low and the intensity of MES is too small throughout the entire recording time, the differentiation of MES from artifact is extremely difficult. Therefore, another useful criterion is needed. We noticed and focused on tail signs (TS), a postembolic signal associated with MES which appeared as a small reversal signal after MES on the high time-resolution spectral display ( Figure 1A). We attempted to determine whether TS were characteristic of the change associated with MES in both animal and clinical studies. Conclusions-TS See Editorial Comment, page 866 Subjects and MethodsThe same TCD machine (Multi-Dop X4, DWL) was used with a multigate 2-MHz probe in both animal and clinical studies.In an animal study, 2 adult pigs weighing 24 to 26 kg, treated with venoarterial extracorporeal membrane oxygenation (VA ECMO) and minima...