Stable isotope dilution gas chromatographic-mass spectrometric (GC-MS) measurement of tricyclic antidepressants (TCA) is a useful alternative to high-performance liquid chromatography (HPLC) methods when interfering substances prevent accurate quantitation by HPLC. For satisfactory GC-MS analysis, secondary amine TCA must be derivatized. Commonly employed trifluoroacetyl and heptafluorobutyryl derivatives are relatively unstable and cause rapid deterioration of capillary GC columns. Therefore we examined 4-carbethoxyhexafluorobutyryl chloride (CHFB-CI) as an alternative derivatizing agent and developed a stable isotope dilution GC-MS method employing ring-labeled [2H4]-desipramine and [2H4]-imipramine internal standards, which permits measurement of desipramine, nortriptyline, imipramine, and amitriptyline in plasma samples containing one or all of these analytes. The GC-MS assay is linear for each analyte from the lower limit of quantitation (25 ng/mL) up to 1500 ng/mL and correlates well with HPLC measurements. The GC-MS analytic coefficient of variation was 9.7 +/- 1.3% for all analytes considered together. Although interferences are observed in the HPLC assay, thioridazine, perphenazine, cyclobenzaprine, and norcyclobenzaprine do not interfere with GC-MS measurements of the TCA examined here. The stability of the CHFB derivative of secondary amine TCA was found to be superior to that of the trifluoroacetyl derivatives of these compounds.
Although bullying is known to have detrimental effects, less is known regarding how these bullies and victims develop within the contexts of their homes and schools, and how early childhood behaviors can predict later bullying/victimization statuses. Parent, teacher, and student reports from the Early Childhood Longitudinal Study-Kindergarten (ECLS-K) 1998-1999 cohort (N = 11,715) representing a nationwide sample of children, were utilized to predict child's bully and victim status in eighth grade (age 13-14) using data from seven collection points. Results indicated child characteristics from the earliest time points identified children at risk for becoming both bullies and victims, although familial characteristics were only able to predict bully status. Identifying these characteristics provides opportunities for early intervention in children's lives, potentially preventing negative effects of bullying and victimization on academic, social, and emotional functioning. Implications for future research, including special considerations for individuals with internalizing behaviors, are discussed.
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