Toxic
E interesant cum alegi sa raspunzi numai la anumite parti din mesajele mele...
Da, sobolani si soareci, caini, cimpanzei... intra pe site-ul bagat in semnatura mea... gasesti informatii extra...
http://www.peta.org/feat/military/http://www.peta.org/feat/baboon/http://www.columbiacruelty.com/etc., etc.,...
Am copiat aici o bucatica de articol, sunt sigura ca intelegi ce se spune si poate ai sa il gasesti interesant.
"Non-animal screening and testing methods hold tremendous promise for reducing or eliminating animal use in the EDSP.
Cell-based (in vitro) assays are generally more sensitive, reliable and relevant than animal-based methods, and produce results more quickly and at a much lower cost. In vitro assays are excellent models for investigating the mechanism of action for hormone-disrupting chemicals and can be performed either individually or in great numbers through automated “high throughput” screening.
In vitro assays available for screening potential hormone-disrupting chemicals include:
Cell-free systems
• Receptor binding and transcriptional activation assays are rapid, non-animal methods of detecting and measuring chemical interactions with cellular receptors for estrogen and androgen hormones (which are associated with female and male sex characteristics, respectively). Many endocrine-disrupting chemicals function by binding to hormone receptor sites on cells, often out-competing the body's naturally-occurring hormones for access to these receptor sites. Receptor binding assays model this activity in vitro. Transcriptional activation assays measure the presence of “gene products,” which are created as a result of receptor binding. Both types of assays are rapid, inexpensive and highly effective in detecting chemicals that mimic estrogen and androgens and interact with their receptors in the cell. In fact, one receptor binding assay was found to be five orders of magnitude more sensitive than the uterotrophic assay.
Cell-based systems
• High throughput screens (HTPS) are automated systems capable of rapid screening of thousands of chemicals. One particularly promising example of an HTPS model is the CALUX (Chemically Activated Luciferase Expression) assay. This method is based on a genetically engineered cell line that responds to specific compounds by producing a chemical called firefly luciferase. For example, when a target chemical enters the cell, it binds to the cellular receptor, which turns on the luciferase, lighting up like a firefly. This assay is currently being adapted to screen for androgen and thyroid active hormones in addition to estrogenic chemicals.
• Cell proliferation assays measure the ability of chemicals to induce cellular proliferation in target organs. The measurement of cell proliferation in vitro can be done using established cell lines derived from hormonally-responsive target organs, including pituitary cells and several human breast cancer cell lines, such as MCF7 and T47-D cells. MCF7 cells, in particular, have been used extensively to screen for hormonally active compounds because they express a gene that regulates estrogen-dependent cell proliferation. Results obtained using these cells are considered to be highly predictive of hormone disrupting action.
• Gene expression assays measure the binding of chemicals to hormone receptors and thereby stimulating the expression of genes by the cell. Several in vitro cell lines have been developed and utilized to test the potency of potential endocrine disruptors. These methods work by measuring the production of specific gene-activation products (e.g., proteins, enzymes, etc.), the appearance of which is indicative of endocrine disruptor-gene interaction.
Structure-Activity Relationship Modeling
Structure-activity relationships (SARs) are based on the principle that the properties and behavior of chemicals are derived directly from their molecular and structural characteristics. Specifically, SARs describe the chemical and/or biological properties of chemicals relative to their molecular structure. Once such a relationship has been established, it can be used to predict the activity of untested chemicals. Consequently, SARs could serve as highly effective tools for screening and prioritizing chemicals for further investigation."
Later edit:
@Ruxi-
Bine ai venit la Han!