Spectroscopy studies of interaction hypericin with an anti-cancer therapy drug doxorubicin.

The presented study was designed to estimate the ability of hypericin to interact with the anticancer drug doxorubicin. The hetero-association of hypericin and doxorubicin was investigated with absorption and fluorescence spectroscopy methods in aqueous solution of DMSO in two-component mixtures: doxorubicin-hypericin and three component mixtures: DNA-doxorubicin-hypericin. The data indicate that hypericin forms complexes with doxorubicin and that the association constants are on the order of 300,000 M-1 in a buffer with 30% DMSO content. The absorption spectra of the hypericin - doxorubicin complexes were examined as well. Owing to its ability to interact with flat aromatic compounds, hypericin may potentially be used as an interceptor molecule to detoxification of patients after chemotherapy.

Nodal areas of potential geographic error in adjuvant radiotherapy for biliary tract cancer.

PURPOSE: To determine the areas of potential geographic error in adjuvant radiotherapy (RT) for biliary-tract cancer (BTC) by comparing pathological-surgical data on the pattern of nodal spread with the extent of elective nodal CTV used in published RT studies in this setting. MATERIAL/METHODS: A literature search was performed to select articles on: 1/adjuvant RT for BTC, that provided information on the lymph node stations (LNS) included in the CTV; 2/the pathological-surgical data on the patterns of nodal involvement/recurrence in BTC. Risk of nodal involvement/recurrence and frequency of inclusion in the CTV in RT studies for each of the LNS were compared to determine the areas of potential geographic misses and unnecessary irradiation, separately for intrahepatic cholangiocarcinoma (IHC), extrahepatic cholangiocarcinoma (EHC) and gallbladder-cancer (GBC). RESULTS: Areas of potential geographic misses include: for right IHC: paraaortic and superior mesenteric artery (SMA) LNS; for left or hilar IHC: left gastric, lesser gastric curvature, paraaortic, and SMA LNS; for proximal EHC: paraaortic LNS; for middle EHC: paraaortic and SMA LNS; for distal EHC: paraaortic, SMA, and anterior pancreatico-duodenal LNS; for GBC: paraaortic, SMA, and posterior pancreatico-duodenal LNS. Celiac-LNS is unnecessarily irradiated for middle/distal EHC. CONCLUSIONS: In view of discrepancies between pathological-surgical data and the CTVs used in common practice, there is an obvious need for international consensus guidelines.

The effect of heating on background and radiation-induced EPR signals in tooth enamel.

The presented study is a continuation of our work performed during participation in the Third International Intercomparison on EPR Tooth Dosimetry. During the process of samples preparation, all 22 enamel samples were accidentally exposed for about 30 min to 150 degrees C temperature. This considerably affected shape of their EPR spectra mainly due to substantial increase in the background signal, which approximately doubled its contribution to the spectra. These effects were studied closer under controlled conditions of the delivered dose and heating temperature using another enamel samples. The observed changes in the spectra shape partially faded within a few days after heating. The heating resulted also in a noticeable generation of a spectral component similar to the dosimetric signal induced in enamel by radiation. The temperature-induced dosimetric component in EPR spectra of the heated samples remained constant for 32 days. Deviations in calculated contributions of the dosimetric signal into total EPR spectra of irradiated sample varied from -12 to +15% of its initial contribution in the non-heated enamel, depending on type of the background spectrum applied in numerical processing of the spectra.