Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Publication year range
2.
Water Sci Technol ; 53(11): 213-9, 2006.
Article in English | MEDLINE | ID: mdl-16862792

ABSTRACT

Using a larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction, we proposed a method for efficiently determining the fish toxicity of organic contaminants in river water. Organic toxicants were 10, 20, 50 and 100-fold concentrated from 4 L of the sample with adsorption cartridges. The lethal effect was observed by exposing every ten individuals of 48-72 h old larval medaka to 20 mL of each solution for 48h. The median lethal concentration rate (LCR50) was used as an indicator for the toxicity. With the developed toxicity test method, more than seven times difference was found in the LCR50 of the river water samples. LCR50 distribution profiles were compared with 125 samples in two typical rivers. The result revealed a lower toxicity level in the mainstream than in the confluences, and a lower toxicity level in Sagami River than in Ayase River. LCR50 proved unique as a toxicity indicator, which was impossible to speculate from the conventional water quality indicator of the dissolved organic carbon concentration. As an effective screening test for priority settings, the method can help us with an efficient planning for the environmental investigation and management.


Subject(s)
Water Pollutants, Chemical/toxicity , Animals , Biological Assay , Dose-Response Relationship, Drug , Embryo, Nonmammalian/drug effects , Environmental Monitoring/methods , Industrial Waste , Oryzias/embryology , Rivers , Time Factors , Toxicity Tests , Waste Disposal, Fluid/methods
3.
Proc Natl Acad Sci U S A ; 103(1): 57-62, 2006 Jan 03.
Article in English | MEDLINE | ID: mdl-16371460

ABSTRACT

The Raf family includes three members, of which B-Raf is frequently mutated in melanoma and other tumors. We show that Raf-1 and A-Raf require Hsp90 for stability, whereas B-Raf does not. In contrast, mutated, activated B-Raf binds to an Hsp90-cdc37 complex, which is required for its stability and function. Exposure of melanoma cells and tumors to the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin results in the degradation of mutant B-Raf, inhibition of mitogen-activated protein kinase activation and cell proliferation, induction of apoptosis, and antitumor activity. These data suggest that activated mutated B-Raf proteins are incompetent for folding in the absence of Hsp90, thus suggesting that the chaperone is required for the clonal evolution of melanomas and other tumors that depend on this mutation. Hsp90 inhibition represents a therapeutic strategy for the treatment of melanoma.


Subject(s)
Cell Cycle Proteins/metabolism , Chaperonins/metabolism , Gene Expression Regulation, Neoplastic/drug effects , Melanoma/metabolism , Mutation, Missense/genetics , Proto-Oncogene Proteins B-raf/metabolism , Animals , Apoptosis/drug effects , Benzoquinones , Cell Cycle Proteins/antagonists & inhibitors , Cell Line, Tumor , Chaperonins/antagonists & inhibitors , Electrophoresis, Polyacrylamide Gel , Enzyme Activation/drug effects , Female , Humans , Lactams, Macrocyclic , Melanoma/genetics , Mice , Mice, Inbred BALB C , Proto-Oncogene Proteins A-raf/metabolism , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins c-raf/metabolism , Rifabutin/analogs & derivatives , Rifabutin/pharmacology
5.
Kangogaku Zasshi ; 37(12): 1589, 1973 Dec.
Article in Japanese | MEDLINE | ID: mdl-4203867

Subject(s)
Japan , Life Expectancy
SELECTION OF CITATIONS
SEARCH DETAIL
...