Reversion tests

R2Cp2Fe Ferrocene R2Cp2Fe<=>R2Cp2Fe++e Cp 0.200 mV vs. Ag/ Reversible test candidate... 

Reversion Tests Background. There are several excellent references describing the background and use of bacteria for reversion tests (Brusick, 1987 Gatehouse et al., 1990). Three different protocols have been widely used plate incorporation assays, treat and plate tests, and fluctuation tests. These methods are described in detail in the following sections. Fundamental to the operation of these tests is the genetic compositions of the tester strains selected for use. 

Ehrlichmann, H. Manh, B. Dott, W. Eisentraeger, A. Development of a miniaturized Salmonella typhimurium reversion test with kinetic data acquisition. In New Microbiotests for Routine Toxicity Screening and Biomonitoring Persoone, G., Janssen, C., De Coen, W., Eds. Kluwer Academic/ Plenum Publishers New York, 2000 503-510. 

Reversibility tests to bronchodilators are recommended at all stages of obstructive airways diseases. They are helpful in differentiating patients with COPD with those of asthma. Many patients with COPD and even those with severe airflow obstruction can demonstrate (partial) reversibility. Patients with a positive bronchodilator response i.e. reversibility are more likely to respond to a trial of oral or inhaled corticosteroids. 

Presently, inhaled steroids (up to the equivalent of BDP 1000 pg/d, budesonide 800 pg/d, fluticasone 500 pg/d) should be given to patients who show an objective response to either oral or inhaled steroids (s. corticosteroid reversibility testing). For those patients who experience no symptomatic relief, the currently available evidence does not support the use of ICS for alteration of the natural history of the disease. Nevertheless, corticosteroids are effective in treating acute exacerbations in COPD and taking patients of off their ICS regimen may lead to deterioration. Oral corticosteroids (e.g. 40 mg prednisolone for ten days) are recommended for exacerbations, if... 

It is recommended that any higher-viscosity product such as residual oil or heavy distillate fuel be evaluated for changes in low-temperature handling properties over time. Testing for reversion in pour point by the Shell Amsterdam Reversion Test or the British Admiralty Pour Point Reversion Test are recommended. Also, viscosity increase versus temperature decrease determinations are recommended for products stored at low temperatures for extended periods of time. 

Identify whether the oil treated with a wax crystal modifier will revert in pour point by testing utilizing either the British Admiralty Pour Point Reversion Test or the Shell Amsterdam Reversion Test. 

De Flora, S., Zanacchi, R, Camoirano, A., Bennicelli, C. Badolati, G.S. (1984) Genotoxic activity and potency of 135 compounds in the Ames reversion test and in a bacterial DNA-repair test. Matot. Res., 133, 161-198... 

Sacks, L.E. MacGregor, J.T. (1982) The B. subtilis multigene spomlation test for mutagens detection of mutagens inactive in the Salmonella his reversion test. Mutat. Res.. 95, 191-202... 

The ion-exchange reaction of the synthetic zeolites NaX and NaY with cobalt, zinc and nickel ions is shown to be non-stoichiometric at low bivalent-ion occupancy, the hydrolytic sodium loss being about twice as large for NaX ( 5 ions/unit cell) as for NaY. The effect is more pronounced at high temperatures and disappears at high occupancies. Reversibility tests in NaX toward zinc and cobalt ions, as studied by a temperature-variation method, show the temperature history to be an important factor in the irreversibility characteristics. The low-temperature partial irreversibility, induced by a high-temperature treatment (45°C) is interpreted in terms of a temperature-dependent occupancy of the small-cage sites by divalent cations, which become irreversibly blocked at low temperature (5°C). 

Reversibility tests were made for cobalt and zinc ions in NaX using a temperature-variation method which is based upon a comparison of the low-temperature equilibria of two identical systems, one of which had been pretreated at a higher temperature. Samples of 50 mg NaX (+5 ml NaCl or 0.01 NaN03) were equilibrated with 40 ml of mixed solutions at 5° and 45°C. After 24 hr, half of the samples at 45°C were transferred to the 5°C thermostat and vice versa. All systems were then shaken for another 24 hr, and the equilibrium solutions were assayed for cobalt or zinc. The initial equivalent fractions of M+2 in the solutions are 0.05, 0.1, and 1. Each individual experiment was performed in duplicate or triplicate, and all assays were made in duplicate. 

The so-called reversion test is carried out by heating specimens floating on talcum powder to above the glass transition temperature. Reversion is then defined as follows ... 

The VC in COPD may be greater than the FVC, because of floppy airways. Spirometry does not distinguish between airflow obstruction due to asthma and COPD, but in conjunction with reversibility testing it can do so. FEV can therefore be diagnostic, assess severity and prognosis and monitor progression of disease. 

Ames reversion test in salmonella typhimurium or Escherichia coli (in vitro)... 

For mutagenic activity, the risk of carcinogens and mutagens compounds which might be presented in the oil was also evaluated according to the international guidelines (OECD 471 and commission directive N° B13/14). Tests have been conducted at the CIT (International Center of Toxicity) Safety and Health Research Laboratories, 27005 Evreux, France. This test evaluates the potential of the Saro essential oil to induce reverse mutation in Salmonella typhimurium, knowing that the bacterial reverse test is able to identify substances that cause point mutations, by affections of DNA base-pairs (19, 20). Five strains of S. typhimurium TA 1535, TA 1537, TA 98 TA 100 and TA 102 were supplied for the study by B.N. Ames Laboratory (University of California, Berkeley or Oakland Research Institute, USA). 

Senderovitz T, Vestbo J, Frandsen J, et al. Steroid reversibility test followed by inhaled budesonide or placebo in outpatients with stable chronic obstructive pulmonary disease. The Danish Society of Respiratory Medicine. Respir Med 1999 93 715-718. 

Tropane-2-carboxylates (21) have been synthesized by reaction of Grignard reagents with anhydroecgonine (21a) was claimed to be 16 times as active as cocaine in the locomotor activity test while (21b) was 64 times as active. Compound (21a) retained only 10—20% of the anaesthetic activity of cocaine. The fluoro-derivative (21b) proved 5—20 times as active as cocaine in the reserpine-induced ptosis prevention and reversal tests, respectively. 

Animal studies indicate that caffeine at high doses produces adverse reproductive effects, causing developmental abnormalities. It tested negative in the histidine reversion-Ames and TRP reversion tests. 

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