Pharmacogenetics 1999 The test substance 13C methacetin itself is considered as is non-toxic and very well tolerated in the used dosage.G. A. Starmer, S. McLean, J. Thomas. Analgesic potency and acute toxicity of substituted anilides and benzamides. Toxicology and Applied Pharmacology 1971;19(1):20-8 Similarly, 13C is a stable, naturally occurring and non-radioactive carbon isotope.
|
|
The S9 fraction has been used in conjunction with the Ames test to assess the mutagenic potential of chemical compounds. Chemical substances sometimes require metabolic activation in order to become mutagenic. Furthermore, the metabolic enzymes of bacteria used in the Ames test differ substantially from those in mammals. Therefore, to mimic the metabolism of test substance that would occur in mammals, the S9 fraction is often added to the Ames test.
|
|
Self- administration of putatively addictive drugs is considered one of the most valid experimental models to investigate drug-seeking and drug-taking behavior. The higher the frequency with which a test animal emits the operant behavior, the more rewarding (and addictive), the test substance is considered. Self-administration of addictive drugs has been studied using humans, non-human primates, mice, invertebrates such as ants, and, most commonly, rats. Self-administration of heroin and cocaine is used to screen drugs for possible effects in reducing drug-taking behavior, especially reinstatement of drug seeking after extinction.
|
|
Macht was known for his pioneering use of a technique he termed phytopharmacology which involved measuring the effects of drugs on plants. Macht's specific technique was to measure the growth rate of Lupinus albus seedlings when dosed with a test substance, and compare this against a control group of undosed seeds. The relative length of root growth would determine what he called the phytotoxic index, and provide a measure of the toxicity of the substance to the plants. Macht applied his technique of phytopharmacology to a variety of substances, including the blood of people suffering from medical conditions.
|
|
The polyphosphonates used in industry differ greatly from natural phosphonates such as 2-aminoethylphosphonic acid, because they are much larger, carry a high negative charge and are complexed with metals. Biodegradation tests with sludge from municipal sewage treatment plants with HEDP and NTMP showed no indication for any degradation. An investigation of HEDP, NTMP, EDTMP and DTPMP in standard biodegradation tests also failed to identify any biodegradation. It was noted, however, that in some tests due to the high sludge to phosphonate ratio, removal of the test substance from solution observed as loss of DOC was observed.
|
|
Most accurate results are obtained near the boiling point of substances and large errors result for measurements smaller than . Procedures often consist of purifying the test substance, isolating it in a container, evacuating any foreign gas, then measuring the equilibrium pressure of the gaseous phase of the substance in the container at different temperatures. Better accuracy is achieved when care is taken to ensure that the entire substance and its vapor are at the prescribed temperature. This is often done, as with the use of an isoteniscope, by submerging the containment area in a liquid bath.
|
|
The screening procedure is called the NCI-60 Human Tumor Cell Lines Screen, and it is one of the Discovery & Development Services of NCI's Developmental Therapeutics Program (DTP). The screening rates for each cell line the cytostatic and cytotoxic impact of tested substances. Due to the diversity of the cell lines, it is possible to compare tested compounds by their effect patterns, high correlation potentially corresponding to similar effect mechanisms. An automated comparison against a database of more than 88,000 pure compounds and more than 34,000 crude extracts () is provided by the COMPARE tool, which shows a list of substances ranked by the Pearson correlation coefficients for a given test substance.
|
|
Irritancy can be measured using the Draize test, where a test substance is applied to an animal's eyes or skin, usually an albino rabbit. For Draize eye testing, the test involves observing the effects of the substance at intervals and grading any damage or irritation, but the test should be halted and the animal killed if it shows "continuing signs of severe pain or distress". The Humane Society of the United States writes that the procedure can cause redness, ulceration, hemorrhaging, cloudiness, or even blindness.Species Used in Research: Rabbit, Humane Society of the United States This test has also been criticized by scientists for being cruel and inaccurate, subjective, over-sensitive, and failing to reflect human exposures in the real world.
|
|