Biomedical subjects

T L Nusair

Publications and source records attributed to T L Nusair.

3 recordsLinked to original sources

PubMed1990

A review of the Buehler guinea pig skin sensitization test and its use in a risk assessment process for human skin sensitization.

The Buehler test is a valuable procedure for screening the sensitization potential of chemicals prior to human exposure. Our experience of over 20 years has shown it to be effective in detecting strong, moderate, and most weak sensitizers. The topical exposure inherent in the Buehler test allows it to be utilized to investigate dose responses, cross reactivity between structurally related chemicals, and the sensitization potential of contaminants in raw material mixtures. For safety assessment purposes, Buehler test results provide an initial indication of the sensitization potential of the material in question under relevant, but exaggerated, exposure conditions. These results can be compared to results on benchmark chemicals to assess sensitization risk for subsequent human exposure. Optimizing the sensitivity of the Buehler test requires adherence to the published methodology and proper interpretation of the challenge and rechallenge data obtained. Adjuvant-type test methods are generally considered to be more sensitive than topical methods. However, when done properly, topical test procedures such as the Buehler test or the open epicutaneous test can accurately detect most chemicals with any realistic potential for sensitizing humans by the topical route. Moreover, from a risk assessment perspective, these topical tests avoid the problems of overestimating the weak sensitization potential of many topically applied materials or underestimating the sensitization potential of very strong sensitizers; both are potential concerns with invasive adjuvant-type test methods. The Buehler test or other topical test methods are particularly valuable for comparative sensitization risk assessment since human sensitization data on benchmark materials are all derived from topical exposure. The risk assessment is developed by comparing the guinea pig data on the new material versus relevant benchmark chemicals or formulations and also by evaluating the existing human sensitization data on the benchmark material. These data are then utilized to predict human sensitization risk from topical exposure to the new material. Confirmation of human safety can be derived from human repeat insult patch testing (HRIPT) and other clinical tests such as the product use test and the diagnostic patch test. Utilized in this manner, the Buehler test is an integral component of an overall skin sensitization safety assessment program for a new chemical or product formulation.

Animals↗

PubMed1990

Antigenic and allergenic characterization of the enzymes alcalase and savinase by crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis.

Alcalase and savinase, produced by Bacillus species, are proteolytic enzymes that are used in laundry products and are known to cause respiratory allergy. Antigenic and allergenic characteristics of alcalase and savinase and their potential cross-reactivity were evaluated using crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis. Alcalase exhibited two distinct antigens; one electropositive and one electronegative. The electropositive antigen exhibited some retrograde anodic mobility when coupled with antiserum components. Savinase exhibited one electropositive and two electronegative antigens. The antigens of the two enzymes were clearly different from each other, the three savinase antigens exhibiting greater electrophoretic mobility than the two alcalase antigens. In crossed radioimmunoelectrophoresis studies, only the electropositive antigen of alcalase, its retrograde complex, and the electropositive antigen of savinase bound IgE from the sera of individuals who were skin test positive to one or both enzymes. No evidence of cross-reactivity was observed in heterologous and tandem crossed immunoelectrophoresis studies and heterologous microimmunodiffusion reactions.

Allergens↗

PubMed1989

A risk assessment process for allergic contact sensitization.

This review describes an approach that has been used to assess the skin sensitization risk of new chemicals and product formulations prior to launching the new chemical or product on the market. The risk assessment process utilizes a comparative toxicological approach, in which data on the inherent toxicity of a material, and the exposure to it through manufacturing or consumer use or foreseeable misuse, are integrated and compared with data generated by 'benchmark' materials of similar chemistry or product application, or both. This approach has been valuable in providing an accurate assessment of the skin sensitization potential for a wide range of consumer products and pharmaceuticals, ranging from products with a very transient skin exposure (e.g. some paper products), to cosmetics, to products whose ingredients may be deposited on fabrics and thus result in chronic skin exposure. The risk assessment process described includes both guinea-pig (Buehler) and human skin sensitization test methodologies to evaluate inherent toxicity under relevant epicutaneous exposure conditions. Alternative guinea-pig test methods have been reported to be more sensitive than the Buehler method, particularly those employing intradermal injection of the test material in Freund's complete adjuvant (e.g. maximization test). However, by bypassing the skin barrier at induction, these methods can overstate the sensitization risk of epicutaneous exposure to weak sensitizers (Andersen and Hamann, 1983 and 1984; Matsushita et al., 1975a,b), and can understate the risk to very strong sensitizers possibly through tolerance induction (Buehler, 1985). In addition, materials are tested and classified at concentrations that may not be relevant to anticipated human exposure. The Buehler guinea-pig test data are important in assessing skin sensitization risk in the early phases of product development, where human exposure can be limited, controlled and monitored (e.g. manufacturing employees). The Buehler test can often define consumer skin sensitization risk; however, the ultimate consumer skin safety assessment should in general be developed through a series of controlled human tests; the human repeat insult patch test and, when necessary, the provocative or extended product use tests. Post-market monitoring of skin-related consumer comments is the final phase of the data gathering process. These results can be used to assess further each product and to provide valuable feedback to confirm the validity of the overall risk assessment process. Risk assessment for skin sensitization potential is seldom a simple process.(ABSTRACT TRUNCATED AT 400 WORDS)

Consumer Product Safety↗