Rapid analytical tryptic mapping of a recombinant chimeric monoclonal antibody and method validation challenges

A rapid and reproducible analytical tryptic mapping method was developed as an identity test for a recombinant chimeric monoclonal antibody for lot release testing. The unfolding, reduction, carboxymethylation, trypsin digestion, and reversed-phase (RP) HPLC steps were optimized to provide a reproducible method. The optimized method requires 30 min for unfolding the protein, 30 min for carboxymethylation, 4 h for digestion with TPCK-trypsin and 140 min for RPHPLC analysis. The total time required is less than 8 h compared to conventional procedures, which must be performed over several days. The optimized method was validated for its precision, recovery, specificity, and robustness. The precision of the method was determined by repeatability and intermediate precision experiments. Relative standard deviation (RSD) values were < or = 10% for the relative peak areas of marker peaks. The mean recovery of these marker peaks was 88.4%. The specificity was demonstrated by the unique tryptic mapping patterns obtained compared with several other monoclonal antibodies. Robustness was demonstrated by the relative insensitivity of the tryptic map to small deliberate changes in key method parameters. Excessive relative peak area variability observed for one peak (RSD 52%) was traced to adsorption to glass autosampler vials. This variability was substantially reduced (RSD 11%) by substituting polypropylene autosampler vials. The data demonstrate that this method may be applicable to a wide range of pharmaceutically relevant monoclonal antibodies.     

Core-Based SCB Fracture of Aligned First-Year Sea Ice (Phases III and IV)

This paper provides the results of two small-scale testing programs linked to large-scale field programs carried out by the writers and others. The large-scale in-situ sea ice testing program was part of the Office of Naval Research's (ONR's) Sea Ice Mechanics Initiative (SIMI). Three field trips to Barrow, Alaska, were completed to examine the seasonal evolution of the first-year sea ice growing on Elson Lagoon. Trips were made in November, March, and May, when significant changes in thickness and temperature profile were evident. The experiments were designed to determine the fracture behavior of sea ice in situ and make comparisons with small-scale lab tests. Due to the unique microstructure of the sea ice tested, it was necessary to complete small-scale (0.1 m) tests for comparative purposes. A detailed study of the ice fabric at the site revealed a very strong alignment of the c-axis. This prompted a study of the fracture properties parallel (hard-fail) and perpendicular (easy-fail) to the preferred c-axes orientation plane in both the largeand small-scale tests. The effects of c-axis alignment, temperature and microstructure on the fracture toughness and tensile strength are investigated.     

Lobular carcinoma of the breast: cytological features supporting the diagnosis of lobular cancer

Lobular carcinomas have a distinct natural history with a better response to endocrine therapy and a higher incidence of local recurrence and are more often bilateral. The cytological diagnosis of lobular carcinoma permits a discriminating therapeutic approach with pre-operative Tamoxifen, more generous resection margins, and assessment of the contralateral breast. The cytological features of lobular cancer however are not well defined and the low cell yield from such neoplasms can result in a high false negative rate. To determine whether we could improve the pre-operative diagnosis, we reviewed the cytological features of 112 lobular carcinomas. They had small uniform sized nuclei with irregular outlines and inconspicuous nucleoli. The degree of dissociation was similar to duct carcinomas and the incidence of inadequate aspirates was no higher. We found no features that confidently diagnosed lobular cancer or its sub-types. However, using a combination of features, typing of lobular cancer on aspirated material is possible and should be attempted.     

Induction of human papillomavirus type 18 late gene expression and genomic amplification in organotypic cultures from transfected DNA templates

The genetic analysis of human papillomavirus (HPV) functions during the vegetative viral life cycle is dependent upon the ability to generate human keratinocyte cell lines which maintain episomal copies of transfected viral genomes. We have previously demonstrated that lipofection of normal human foreskin keratinocytes with recircularized cloned HPV-31 genomic sequences resulted in a high frequency of cell lines which maintained viral genomes as extrachromosomal elements (M.G. Frattini, H. Lim, and L.A. Laimins, Proc. Natl. Acad. Sci. USA 93:3062-3067, 1996). Following the growth of these cell lines in organotypic (raft) cultures, the differentiation-dependent expression of viral late genes, the amplification of viral genomes, and virion biosynthesis were observed. In the present study, we demonstrate that these methodologies are not restricted to HPV-31 but are applicable to other HPV types, including the oncogenic HPV-18. HPV-18 genomes were purified from bacterial vector sequences, religated, and transfected into normal human foreskin keratinocytes together with a neomycin-selectable marker. Following drug selection, resistant cells were expanded and examined for the state of the viral DNA. All cell lines examined were found to contain approximately 100 to 200 episomal copies of HPV-18 DNA per cell. Growth of these cell lines in raft cultures resulted in the differentiation-dependent expression of the E1 [symbol: see text] E4 and L1 capsid genes. In addition, viral genome amplification was observed in suprabasal cells following DNA in situ hybridization analysis of differentiated raft cultures. The induction of these late viral functions has previously been shown to be directly associated with differentiation-dependent virion biosynthesis. Our studies indicate the ability to perform a detailed genetic analysis of the various phases of the viral life cycle, including control of the differentiation-dependent late viral functions, using a second oncogenic HPV type.     

Cloning and mapping of murine Nfe2l1

The murine homologue of the human NFE2L1 basic leucine-zipper gene was isolated from an early embryo library. The deduced amino acid sequence shows 97% identity between the two proteins. Significant sequence similarity is also seen with the p45 subunit of NF-E2 and with the Drosophila CNC protein. Murine Nfe2l1 maps to chromosome 11DE with similar sequence at 7D1-7F1 and 2E4-2G.