| 1. |
- Svensson, Samuel, 1962-, et al.
(författare)
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Melanin inhibits cytotoxic effects of doxorubicin and daunorubicin in MOLT 4 cells
- 2003
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Ingår i: Pigment Cell Research. - : Wiley. - 0893-5785 .- 1600-0749. ; 16:4, s. 351-354
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Tidskriftsartikel (refereegranskat)abstract
- In the present study we have developed a simple method to elucidate the melanin binding ability of different chemotherapeutic agents. The anthracyclines, doxorubicin and daunorubicin, or the alkylating agent cisplatin were preincubated with melanin (Sepia). Melanin and free drug was then separated through centrifugation and the cytotoxic effects of corresponding drug were evaluated in a MTT (3-(4,5-dimetyltiazol-2-yl)-2,5-difenyl-tetrazoliumbromide) assay using MOLT-4 cells. Our results show that melanin pretreatment shifted the IC50 value for doxorubicin from 0.06 to 0.97 ╡M and for daunorubicin from 0.04 to 0.80 pM. In contrast, the IC50 values of cisplatin was not influenced by melanin pretreatment indicating that cisplatin does not bind to melanin. By comparing equi-active concentrations from concentration-response curves with or without melanin pretreatment an approximate binding capacity of melanin could be estimated. Our results show that melanin binds about 900 nmol/mg doxorubicin and 760 nmol/mg daunorubicin. Chloroquine, which is known to bind to melanin with high affinity, was found to inhibit melanin binding of both daunorubicin and doxorubicin, thereby leading to an increased sensitivity of the anthracyclines. The clinical implications of melanin binding regarding unwanted accumulation of anthracyclines in the skin as well as chemoprotective effects against chemotherapy are discussed.
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| 2. |
- Wallmo, Henrik, 1977, et al.
(författare)
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The influence of hemicelluloses during the precipitation of lignin in kraft black liquor
- 2009
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 24:2, s. 165-171
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Tidskriftsartikel (refereegranskat)abstract
- Removing lignin from black liquor is one way of recovering valuable organic substances for alternative use as well as reducing the energy surplus in a modern, energy-optimised kraft pulp mill. By using the recently developed "LignoBoost" process it is possible to upgrade black liquor streams of different origin to form valuable chemicals. In this investigation a combination of membrane filtration and the LignoBoost concept was used. The primary objective of the work was to investigate whether or not the filtration properties of the black liquor were affected by its hemicellulose content. The hemicellulose content in the black liquors was lowered prior to precipitation using three different pre-treatment techniques, and the filtration properties were compared to the reference black liquors of evaporated softwood and hardwood black liquor. The pre-treatment methods used were heat-treatment, ultrafiltration and a combination of ultrafiltration and nanofiltration. It was shown that the filtration resistance was lowered considerably when the hemicellulose content in the black liquor was reduced prior to precipitation. The experiments also showed that it was possible to produce a hardwood lignin product of high purity i.e. low sodium (0.2 w-% of TIDS) and hemicellulose content (0.7 w-% of TDS)
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