SDS-PAGE under non-reducing conditions is one of the most commonly used techniques for recombinant monoclonal antibody purity and stability indicating assay. On non-reducing SDS-PAGE, bands with a lower molecular weight than the intact antibody are routinely observed and is a common feature of IgG molecules. These fragments were analyzed by in-gel digestion followed by matrix-assisted-laser-desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry, Western blot and by comparing the banding pattern of sample prepared in the presence of a reducing reagent. The fragments bands were identified as antibody lacking one light chain, two heavy chains, one light chain and one heavy chain, free heavy chain and free light chain. Sensitivity of fragmentation to sample buffer pH, incubation time, reducing reagent and alkylation reagents indicated that fragments were formed during sample preparation, but not present in the samples analyzed. Disulfide bond scrambling and beta-elimination are the two major mechanisms of the formation antibody fragments. Mass spectrometry analysis suggested that disulfide bond scrambling can be prevented by specifically modifying free sulhydryl using alkylation and thus reduced the amount of artifacts on non-reducing SDS-PAGE. Breakage of disulfide bonds by beta-elimination was evidenced by the detection of dehydroalanine using mass spectrometry.

We conducted a population-based prospective cohort study to help elucidate the predictive relationship between a maternal prebirth self-reported history of intimate partner violence (IPV) and any postbirth reported allegation to Child Protective Services (CPS) by age 2. We linked data from the 2009-2010 Alaska Pregnancy Risk Assessment Monitoring System with CPS data through 2012. Among this cohort, we found that 8.0%w self-reported experiencing IPV 12 months prior or during pregnancy, and 8.0%w of the offspring experienced at least one CPS report of alleged maltreatment during the study period. The predictive relationship varied by maternal educational attainment. Among mothers with 12+ years education completed, the odds of a CPS report were 3.9 times compared to those with no IPV, while among mothers with <12 years education completed, no association was noted. These results suggest that for a subset of Alaskan families, maternal history of IPV is a strong independent predictor of future CPS contact.

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