Motivating Self-Efficacy in Diverse Biomedical Science Post-baccalaureate and Graduate Students Through Scientific Conference Implementation.

Tactics to increase the number of underrepresented (UR) students in biomedical research PhD training programs have not yet translated to UR faculty numbers that reflect the diversity of the United States. Continued interventions are required to build skills beyond those that result in placement into a PhD program. We hypothesize that successful interventions must build skills that give UR students foundations for confident self-efficacy in leadership. We seek interventions that allow UR students to envision themselves as successful faculty. We posit that development of such skills is difficult in the classroom or laboratory alone. Therefore, novel interventions are required. As part of the NIH-funded Post-baccalaureate Research Education Program (PREP) and Initiative for Maximizing Student Development (IMSD) at the Mayo Clinic Graduate School of Biomedical Sciences, we designed and implemented a unique intervention to support development of student leadership skills: a biannual student-organized and student-led national research conference titled "Scientific Innovation Through Diverse Perspectives" (SITDP). This initiative is based on the concept that students who actively live out realistic roles as scientific leaders will be encouraged to persist to scientific leadership as faculty. Here we describe the motivation for, design of, and outcomes from, the first three pilot conferences of this series. We further discuss approaches needed to rigorously evaluate the effectiveness of such interventions in the future.

Erythrocyte mean corpuscular volume as a surrogate marker for 6-thioguanine nucleotide concentration monitoring in patients with inflammatory bowel disease treated with azathioprine or 6-mercaptopurine.

Mean corpuscular volume may correlate with erythrocyte 6-thioguanine nucleotide concentrations in patients treated with azathioprine and 6-mercaptourine. We conducted a study of 166 patients with inflammatory bowel disease treated with azathioprine or 6-mercaptopurine to determine the relationship between mean corpuscular volume and erythrocyte 6-thioguanine nucleotide concentrations, disease activity as measured by the Inflammatory Bowel Disease Questionnaire (active disease <170, remission >170), and leukopenia. Blood was submitted for mean corpuscular volume, whole blood 6-thioguanine nucleotide concentration, and leukocyte count. The mean +/- SD mean corpuscular volume during treatment was 94.7 +/- 6.6 fL and the mean +/- SD change in mean corpuscular volume was 7.5 +/- 6.3 fL. There were significant correlations between mean corpuscular volume and erythrocyte 6-thioguanine nucleotide concentration (r(s) = 0.33, p < 0.001) and between change from baseline in mean corpuscular volume and erythrocyte 6-thioguanine nucleotide concentration (r(s) = 0.26, p = 0.001). There was no correlation between Inflammatory Bowel Disease Questionnaire scores and mean corpuscular volume values (r(s) = 0.01, p = 0.94). The mean corpuscular volume values in 55 patients with active disease and 111 patients in remission were similar (95.1 vs. 94.5 fL, p = 0.57). There was a weak negative correlation between the mean corpuscular volume and the leukocyte count, (r(s) = -0.18, p = 0.022). In patients with inflammatory bowel disease treated with azathioprine or 6-mercaptopurine, mean corpuscular volume and change from baseline in mean corpuscular volume correlated with erythrocyte 6-thioguanine nucleotide concentrations and negatively with leukocyte counts, but did not correlate with disease activity as measured by the Inflammatory Bowel Disease Questionnaire. Measurement of mean corpuscular volume is a simple and inexpensive alternative to measurement of 6-thioguanine nucleotide concentrations in patients treated with azathioprine or 6-mercaptopurine.

Chemical modifications to study mutations that affect the ability of the general base (E268) to function in human liver mitochondrial aldehyde dehydrogenase.

The action of a general base is needed in two possible steps during the aldehyde dehydrogenase catalyzed oxidation of an aldehyde to an acid. The base is glutamate at position 268 in the cytosolic and mitochondrial class 1 and 2 enzyme. A chemical modification approach was undertaken to determine if the base were necessary in the initial attack of the nucleophilic cysteine (302) on the aldehyde as well as the attack by water on the acyl intermediate formed after the aldehyde is oxidized. A metabolite of disulfiram, S-methyl-N,N-diethylthiocarbamoyl sulfoxide (MeDTC-SO), was used as the modifying agent. Three recombinantly expressed mutant forms of the human mitochondrial enzyme along with the native one were used. These were the E268Q mutant that was lacking the general base; the E487K Oriental variant of the enzyme and R475Q, a mutant possessing the residue that binds to E487. As expected, the E268Q mutant was inactivated very slowly compared with the native or other mutants that were inactivated more slowly than the native enzyme. The presence of NAD did not increase the rate of inactivation except with the R475Q mutant. It is concluded that it is necessary to activate the cysteine at the active site to make it a good nucleophile as well to activate water during the hydrolysis of the thio-acyl intermediate. Further, it is surmised that the reason some mutants have a lowered specific activity is that in those the general base is not capable of functioning as it does in the native enzyme.

Pharmacokinetics and tissue distribution of a peptide nucleic acid after intravenous administration.

Peptide nucleic acids (PNAs) are DNA analogs that hybridize to complementary nucleic sequences with high affinity and stability. In our previous work, we showed that a PNA complementary to a 12-base pair (bp) sequence of the coding region of the rat neurotensin receptor (rNTR1) mRNA is effective in significantly blocking a rat's central responses to neurotensin (NT), even when the PNA is injected intraperitoneally (i.p.). Using a novel gel shift detection assay to detect PNA, we have now used this same PNA sequence to derive its pharmacokinetic variables and its tissue distribution in the rat. The PNA has a distribution half-life of 3 +/- 3 minutes and an elimination half-life of 17 +/- 3 minutes. The total plasma clearance and volume of distribution of this PNA were 3.4 +/- 0.9 ml/min x kg and 60 +/- 30 ml/kg. Two hours after dosing, the PNA was found at detectable but low levels in all organs examined-in order of decreasing concentration: kidney, liver, heart, brain, and spleen. Approximately 90% of the PNA dose was recovered as unchanged parent compound in the urine 24 hours after administration.