Perceptions of Retinal Imaging Technology for Verifying the Identity of 4-H Ruminant Animals

The purpose of the study reported here was to determine the perceptions of 4-H members and volunteers regarding the retinal imaging process as an innovative method to verify the identity of 4-H animals. Participants were surveyed to determine the perceived strengths and weaknesses of the retinal imaging process and to determine whether participants consider retinal imaging to be beneficial to the Indiana 4-H program. Retinal imaging was perceived to be an accurate and efficient method of livestock identification by both 4-H members and adult volunteers. Volunteers determined that their ability to capture a retinal image requires skill and practice

An Evaluation of Retinal Imaging Technology for 4-H Beef and Sheep Identification

The study reported here evaluated retinal imaging technology as a means of permanent identification of 4-H beef and sheep. The OptiReader» Device was used to capture digital images of 491 beef and 220 sheep during 4-H enrollment. A total of 317 beef and 159 sheep were re-imaged. The on-site visual verification rate was 96.2% for beef and 100% for sheep. A visual verification exercise showed that individuals could identify a pair of retinal images as a match 98.6 % of the time for beef. Retinal imaging is a viable method for enrolling beef and sheep

Elicitation of the immune response to p-phenylenediamine in allergic patients: the role of dose and exposure time

Background Usage of hair dye products containing p-phenylenediamine (PPD) is a concern for PPD-allergic individuals. Objectives The present study investigates the role of dose and exposure time on elicitation of allergic contact dermatitis under conditions of permanent hair dyeing. Methods Elicitation responses after application of a typical hair dye product containing 2% PPD for 30 min followed by rinsing were analysed in 38 PPD-allergic individuals with a documented history of hair dye-related allergy. Skin binding experiments in vitro were performed to distinguish the dose available for elicitation from the dose applied. Results A positive reaction was elicited in 20 of 20 patients with grades ++ to +++ and 12 of 18 with grade + according to the classification of the International Contact Dermatitis Research Group. Under conditions of diagnostic patch testing (48 h exposure), the dose available for elicitation is more than 10-fold higher compared with the dose available for hair dyeing (30-min exposure, rinsing of product). Conclusions This investigation demonstrates that under simulated hair dye use conditions the actual exposure to PPD is more than an order of magnitude lower than under diagnostic patch testing, although sufficient to elicit a clearly noticeable reaction in 84% of PPD patch test-positive individuals

Para-phenylenediamine and allergic sensitization: risk modification by N-acetyltransferase 1 and 2 genotypes

Background Para-phenylenediamine (PPD) is a common contact sensitizer causing allergic contact dermatitis, a major skin problem. As PPD may need activation to become immunogenic, the balance between activation and/or detoxification processes may influence an individual's susceptibility. PPD is acetylated and the metabolites do not activate dendritic-like cells and T cells of PPD-sensitized individuals. Objectives To investigate whether PPD can be acetylated in vitro by the two N-acetyltransferases 1 (NAT1) and 2 (NAT2). Based on the assumption that N-acetylation by NAT1 or NAT2 is a detoxification reaction with respect to sensitization, we examined whether NAT1 and NAT2 genotypes are different between PPD-sensitized individuals and matched controls. Methods Genotyping for NAT1 and NAT2 polymorphisms was performed in 147 PPD-sensitized individuals and 200 age- and gender-matched controls. Results Both PPD and monoacetyl-PPD were N-acetylated in vitro by recombinant human NAT1 and to a lesser extent by NAT2. Genotyping for NAT1*3, NAT1*4, NAT1*10, NAT1*11 and NAT1*14 showed that genotypes containing the rapid acetylator NAT1*10 allele were under-represented in PPD-sensitized cases (adjusted odds ratio 0.72, 95% confidence interval 0.45-1.16). For NAT2, NAT2*4, NAT2*5AB, NAT2*5C, NAT2*6A and NAT2*7B alleles were genotyped. Individuals homozygous for the rapid acetylator allele NAT2*4 were under-represented in cases compared with controls (4.3% vs. 9.4%), but this trend was not significant. Conclusions With respect to data indicating that NAT1 but not NAT2 is present in human skin, we conclude that NAT1 genotypes containing the rapid acetylator NAT1*10 allele are potentially associated with reduced susceptibility to PPD sensitization