Within- and between-laboratory reproducibility and predictive capacity of amino acid derivative reactivity assay (ADRA) using a 0.5 mg/mL test chemical solution: Results of the study for reproducibility confirmation implemented in five participating laboratories.

The amino acid derivative reactivity assay (ADRA) is an in chemico alternative assay for skin sensitization listed in OECD test guideline 442C. ADRA evaluates the reactivity of sensitizers to proteins, which is key event 1 in the skin sensitization adverse outcome pathway. Although the current key event 1 evaluation method is a simple assay that evaluates nucleophile and test chemical reactivity, mixtures of unknown molecular weights cannot be evaluated because a constant molar ratio between the nucleophile and test chemical is necessary.

The within- and between-laboratories reproducibility and predictive capacity of Amino acid Derivative Reactivity Assay using 4 mM test chemical solution: Results of ring study implemented at five participating laboratories.

Amino acid derivative reactivity assay (ADRA) for skin sensitization was adopted as an alternative method in the 2019 OECD Guideline for the Testing of Chemicals (OECD TG 442C). The molar ratio of the nucleophilic reagent to the test chemicals in the reaction solution was set to 1:50. Imamura et al.

Oxidation of a cysteine-derived nucleophilic reagent by dimethyl sulfoxide in the amino acid derivative reactivity assay.

The amino acid derivative reactivity assay (ADRA), which is an in chemico alternative to the use of animals in testing for skin sensitization potential, offers significant advantages over the direct peptide reactivity assay (DPRA) in that it utilizes nucleophilic reagents that are sensitive enough to be used with test chemical solutions prepared to concentrations of 1 mm, which is one-hundredth that of DPRA. ADRA testing of hydrophobic or other poorly soluble compounds requires that they be dissolved in a solvent consisting of dimethyl sulfoxide (DMSO) and acetonitrile. DMSO is known to promote dimerization by oxidizing thiols, which then form disulfide bonds.

The within- and between-laboratory reproducibility and predictive capacity of the in chemico amino acid derivative reactivity assay: Results of validation study implemented in four participating laboratories.

The amino acid derivative reactivity assay (ADRA) is an in chemico alternative method that focuses on protein binding as the molecular initiating event for skin sensitization. It is a simple and versatile method that has successfully solved some of the problems of the direct peptide reactivity assay (DPRA). The transferability and within- and between-laboratory reproducibility of ADRA were evaluated and confirmed as part of a validation study conducted at four participating laboratories.

Cause of and countermeasures for oxidation of the cysteine-derived reagent used in the amino acid derivative reactivity assay.

The amino acid derivative reactivity assay (ADRA) is an in chemico alternative to animal testing for skin sensitization that solves certain problems found in the use of the direct peptide reactivity assay (DPRA). During a recent validation study conducted at multiple laboratories as part of the process to include ADRA in an existing OECD test guideline, one of the nucleophilic reagents used in ADRA-N-(2-(1-naphthyl)acetyl)-l-cysteine (NAC)-was found to be susceptible to oxidation in much the same manner that the cysteine peptide used in DPRA was. Owing to this, we undertook a study to clarify the cause of the promotion of NAC oxidation.

Effective induction of oral anaphylaxis to ovalbumin in mice sensitized by feeding of the antigen with aid of oil emulsion and salicylate.

It is important to evaluate the ability of novel proteins in food crops and products to elicit potentially harmful immunologic responses, including allergic hypersensitivity. We developed a novel mouse model of food allergy involving an oral challenge of a protein antigen after feeding of the antigen in combination with modulating factors often ingested in daily life, namely, dietary oil emulsion and salicylate. In the model, BALB/c mice were sensitized orally for three weeks with ovalbumin (OVA) in linoleic acid/lecithin emulsion, followed immediately by intraperitoneal injection of sodium salicylate.

Effects of transmaternal exposure to genistein in Hatano high- and low-avoidance rats.

Hatano high- and low-avoidance (HAA and LAA) rats are separated by breeding from Sprague-Dawley rats by high versus low rates of avoidance responses in a shuttle-box task. In addition, compared to HAA rats, LAA rats show lower running-wheel activity, later sexual maturation, 5-day estrous cycling, lower sperm motility, more pronounced immunological reactions, and are generally less reactive to stress. The present study was designed to compare the effects of transmaternal exposure to genistein on these characteristics between HAA and LAA rats.

Immunological characteristics of Hatano high-and low-avoidance rats.

Hatano high- and low-avoidance (HAA and LAA) rats have been genetically selected on the basis of their two-way active avoidance behavior, and have been shown to differ in other behavioral and hormonal parameters. Since close interconnections among the nervous, endocrine and immune systems have been well documented, these two strains might possess differences in aspects of immunological action. In Experiment 1, plasma levels of IgG, IgM, complement 3 (C3), classical pathway hemolytic complement (CH50) and beta(2)-microglobulin were compared between males of the two strains at 5 and 24 weeks of age.

Strain differences in the spontaneous incidence of sperm morphological abnormalities in Hatano rats.

Two inbred strains of Hatano rats, which had been bred selectively on the basis for shuttlebox avoidance responses (high- and low-avoidance animals; HAA and LAA), were different in sperm motility. We have found that there are strain differences in the spontaneous incidence of sperm morphological abnormalities. The percentages of abnormalities were extraordinarily higher in the LAA rats, whose sperm motility was lesser.

Differences in sperm motion between high- and low-shuttlebox avoidance rats (Hatano strains).

Sperm from the caudal epididymis of 2 inbred strains of Sprague-Dawley (SD) rats, selected on the basis of their high- or low-shuttlebox avoidance responses, were analyzed for motion characteristics by a computer-assisted sperm motion analysis (CASA) system. Sperm motion in high-avoidance animals (HAA) was characterized by high velocities, high amplitude of lateral head displacement (ALH), and low beat cross frequency (BCF). Conversely, sperm from low-avoidance animals (LAA) displayed low velocities, low ALH, and high BCF.