Statistical procedures for estimating the detection limit and determination limit of the Ames Salmonella mutagenicity assay

Takanashi, Hirokazu; Urano, Kohei

doi:10.1016/s0048-9697(98)00264-2

Cited by 17 publications

(7 citation statements)

References 20 publications

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“…The preincubation method of the Ames assay was adopted (Takanashi & Urano 1998). In order to identify the other presumed byproducts, 3-methyl-4-nitrophenol and 4-nitrophenol were chlorinated.…”

Section: Sterilize By Filtrationmentioning

confidence: 99%

Chlorination by-products of fenitrothion

Kishida

Kumabe

Takanashi

et al. 2010

Water Science and Technology

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The mutagens produced through chemical reaction between chlorine and the insecticide fenitrothion were studied by using a quadrupole GC-MS. The mutagenicity and the mutagen formation potential (MFP) of the identified by-products were evaluated by the Ames assay (preincubation method) using Salmonella typhimurium TA100 without exogenous activation by S9 mix (TA100-S9). Before conducting GC/MS analyses, six compounds were presumed to be produced in chlorinated fenitrothion. These compounds were confirmed to be produced by the GC/MS analyses, but none of them were mutagenic. One of the chlorination by-products, 3-methyl-4-nitrophenol, has 19 times greater MFP than that of fenitrothion. This result suggests that a major mutagen in chlorinated fenitrothion will be produced via a chemical reaction between chlorine and 3-methyl-4-nitrophenol.

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Section: Sterilize By Filtrationmentioning

confidence: 99%

Chlorination by-products of fenitrothion

Kishida

Kumabe

Takanashi

et al. 2010

Water Science and Technology

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“…The test was performed with the method using Salmonella typhimurium TA100 strains, without exogenous activation (S9). The assay was performed with 3 or 4 dose steps, and with duplicate plates for each step (Takanashi and Urano, 1998). Quadruplet plates were used for the negative control tests.…”

Section: Ames Salmonella Mutagenicity Assaymentioning

confidence: 99%

“…In this study, test results with an MR value over 1.4 were deemed positive, because quadruplet plates were used for the negative control steps (Takanashi and Urano, 1998). The detection limit of the assay (DL), was calculated according to equation (2):…”

Section: Ames Salmonella Mutagenicity Assaymentioning

confidence: 99%

Mutagen Formation Potential (MFP) of Kotsuki River Water and Contribution of Pesticides to MFP

Abiru

Takanashi

Kishida

et al. 2011

J. of Wat. & Envir. Tech.

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The contribution of selected pesticides to the mutagen formation potential (MFP) of river waters was studied. The concentrations of the pesticides in river water samples were determined by means of a quadrupole GC-MS. Twelve out of 39 pesticides measured were detected in the water samples collected from Kotsuki River. Ames mutagenicity assays (preincubation method) using Salmonella typhimurium TA100 without metabolic activation by S9 mix (TA100-S9) were performed to measure the MFP. From all the samples collected, significant MFPs were detected. The maximum contribution of the pesticides to the MFP of the river water samples was 0.11%, indicating that the effect of the pesticides found in this study on the MFP of the river water samples is insignificant. The contribution of pesticide degradation products to the MFP of river waters should be investigated in order to see whether pesticide degradation products affect the MFP of river waters.

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“…The dependencies between k-fold rule, sample size, false-positive rates, false-negative rates and the design has been discussed by Takanashi & Urano (5). The use of the two-fold rule for the mouse lymphoma assay has been discussed by Oberly et al (6).…”

Section: A Two-stage Procedures For the Statistical Proof Of Safetymentioning

confidence: 99%

Two-stage Testing of Safety: A Statistical View

Hauschke

Hothorn

2003

Altern Lab Anim

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Sample sizes given in regulatory guidelines are not based on statistical reasoning. However, from an ethical, scientific, and regulatory point of view, a mutagenicity experiment must have a reasonable chance of supporting the decision as to whether a result is negative or positive. Consequently, the sample size should be based on type I and type II errors, the underlying variability, and the specific size of a treatment effect. A two-stage adaptive interim analysis is presented, which permits an adaptive choice of sample size after an interim analysis of the data from the first stage. Because the sample size of the first stage is considered to be a minimum requirement, this stage can also be regarded as a pilot study.

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Statistical procedures for estimating the detection limit and determination limit of the Ames Salmonella mutagenicity assay

Cited by 17 publications

References 20 publications

Chlorination by-products of fenitrothion

Chlorination by-products of fenitrothion

Mutagen Formation Potential (MFP) of Kotsuki River Water and Contribution of Pesticides to MFP

Two-stage Testing of Safety: A Statistical View

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