The accuracy and precision of the determination of
238Pu amount at the fg (mBq) level by a combination of alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS) were studied ...using a standard reference material (CRM 136—Plutonium Isotopic Standard, National Bureau of Standards, Washington, D.C., USA). The activity of
238Pu was calculated from the amount of
239Pu and
240Pu obtained by isotope dilution method and ICP-MS combined with the intensity ratio of
238Pu/
239,240Pu obtained by alpha spectrometry without adding spike. The results show that approximately 130
fg of
238Pu can be analyzed within an accuracy of 7% bias and with 5–12% of total uncertainty. The examined analytical procedure was applied to the quantitative analysis of
238Pu in water samples representing Safeguards inspection samples. The combination of alpha spectrometry and ICP-MS is useful for quantitative and isotopic analysis in low-level Pu samples. Also the method leads to improving the accuracy of
238Pu determination because efficiency calibration is not necessary for alpha spectrometry.
Macrophages and dendritic cells (DCs) are important contributors to anti-tumor immune responses. However, these highly plastic cells are also the primary targets of tumor manipulation, which may ...result in the development of tumor-promoting subtypes. The effect of chemotherapeutic agents on tumor cells is an area of intense study, but little is known about their effects on innate immune cells.
We investigated the effects of four chemotherapeutic drugs (two platinum-based agents; oxaliplatin and cisplatin, and two anthracyclines; doxorubicin and epirubicin) on the differentiation, function, and viability of macrophages and DCs. Macrophages and DCs were differentiated from monocytes in the presence of these chemotherapeutic drugs and we compared their cell surface receptor expression, cytokine production, and chemotactic- and T-cell-polarizing ability.
We have shown that differentiation in the presence of anthracyclines dose-dependently increases CTLA-4 expression in DCs. Antineoplastic agent-driven differentiation strongly modified the CCL2- or CCL5-induced chemotactic activity of both macrophages and DCs. DCs differentiated in the presence of high-dose cisplatin and a low dose of epirubicin promoted regulatory T-cell development, whereas oxaliplatin at specific doses induced both DCs and macrophages to enhance cytotoxic T-cell responses. Furthermore, we found that inflammatory macrophages are more sensitive to doxorubicin-induced cell death than their counterparts.
In summary, our results confirm that chemotherapeutic agents acting on a similar basis may have different effects on the anti-tumor immune response. Treatment with optimal dose, combinations, and timing of chemotherapy may determine tumor immunity and the metastatic potential of tumors.
