Development and evaluation of immunoassay for zeranol in bovine urine.

A high affinity polyclonal antibody-based enzyme linked immunosorbent assay (ELISA) was developed for the quantification of zeranol in bovine urine. On the basis of urine matrix studies, the optimized dilution factors producing insignificant matrix interference were selected as 1:5 in pretreatment. In the improved ELISA, the linear response range was between 0.

[Conditional targeting of p16(INK4a)exon 1a in mouse embryonic stem cells].

Objective: To study the relationship between targeting vector structure and homologous recombination rate and investigate whether the mouse p16(INK4a) plays a role in tumor suppression.

Methods: A conditional targeting vector with 2.0 kb EcoR I/Xba I fragment as short arm and 5.

[p16INK4a exon 1 alpha knockout in mouse embryonic stem cells].

INK4a/ARF locus distinguishes itself by its unusual structure and function. It contains 2 overlapping genes with exons 1 alpha, 2 and 3 encoding p16INK4a and exons 1 beta, 2 and 3 encoding p19ARF. Mice with their exons 2 and 3 of the INK4a/ARF knocked out are viable and fertile but develop spontaneous tumors at an early age and highly sensitive to carcinogenic treatment.