[Effects of magnetic resonance imaging on neutrophil functions].

We evaluated the effects of magnetic resonance (MR) imaging on human neutrophil functions. In addition of the counting of leukocyte and neutrophil number, expression levels of adhesion molecules on neutrophil surface such as CD11b and L-selectin, and reactive oxygen species (ROS) production were determined by means of flowcytometry. Complete blood count did not show any difference between before and after MR imaging in five normal healthy volunteers. The levels of cell surface adhesion molecules were not altered in both in vivo MR imaging (n=5) and in vitro MR exposure experiments (n=13). Moreover, the levels of ROS production were also not affected by in vivo MR imaging. On the other hand, neutrophils exposed to MR in vitro exhibited significant increase in ROS production after stimulation with fMLP combined with lipopolysaccharide, although no increase was observed with PMA stimulation. Actually, there have been no reports describing the complication relating to hyper-neutrophil function as far as we could search, but it might be necessary to evaluate the biological effects of MR imaging especially under the pathologic circumstances that induce neutrophil activation.

[Evaluation of a non-invasive hemoglobin measurement device for pre-deposited autologous blood donation].

A non-invasive hemoglobin measurement instrument (Sysmex Co.Ltd., Kobe, Japan) was used for the evaluation of hemoglobin levels just before blood drawing for repeat autologous blood donation. There was a statistically significant correlation (r = 0.598) between the hemoglobin levels determined with the non-invasive instrument (NINV-Hb) and true Hb levels (T-Hb) evaluated by direct analysis with automatic hematology analyzer, KX-21 (Sysmex). The analysis used 156 data obtained from 66 patients. Ten patients whose differences between NINV-Hb and T-Hb of the first blood donation were more than 2.1 g/dl were excluded from further analysis. Imaging analysis indicated difficulties with the detection of appropriate blood vessel images in one of these patients, but the reasons for other patients were not apparent. There was a closer relationship between NINV-Hb and T-Hb for the 76 measurements for the second or third blood donation obtained from 56 patients (r = 0.704) than for the entire data (r = 0.598). When 12 g/dl was used as the cut off value for NINV-Hb, sensitivity and specificity for the detection of 1l g/dl of T-Hb, which is considered the critical level for drawing autologous blood for donation, were 83.6% and 77.8%, respectively. We conclude, therefore, that NINV-Hb evaluation can be expected to be useful for repeated autologous blood donation of limited patients, however, it is strongly expected to develop a new system having more sensitive and accurately detectable ability.

Albumin attenuates neutrophil activation induced by stimulators including antibodies against neutrophil-specific antigens.

As neutrophil activation is related to several adverse transfusion reactions, we studied about the activation induced by anti-neutrophil antibodies and the stabilizing effects of albumin pretreatment by means of flow cytometry. Anti-neutrophil monoclonal antibody (anti-HNA-1a, 1b, 2a) alone induced CD11b expression and shedding of L-selectin, and anti-HNA-1a reinforced reactive oxygen species (ROS) production. Albumin pretreatment significantly reduced CD11b expression and L-selectin shedding induced by fMLP and ROS production induced by PMA, G-CSF combined with PMA or LPS-fMLP, or anti-HNA-1a combined with PMA. These findings suggest that anti-HNA-1a is related to adverse reactions and albumin has a regulating effect on neutrophil activation.