The effect of remuneration schedule on data completion and retention in the pregnancy eating attributes study (PEAS).

Maximizing data completion and study retention is essential in population research. This study examined the effect of remuneration schedule and data collection modality on data completion and retention in the Pregnancy Eating Attributes Study cohort. Participants (n = 458) completed online surveys and attended six in-person study visits. Initially, remuneration was a prespecified amount per visit, then was changed mid-study to be prorated based on the number of forms completed. Additionally, survey data collection modality was changed to in-person at the sixth study visit. In this secondary data analysis, there was no effect of remuneration schedule on withdrawal rates or time-to-withdrawal. Survey completion was significantly lower under prorated remuneration at the first visit but did not significantly differ at subsequent visits. The lump sum group had significantly greater odds of completely the first and second trimester dietary record (OR = 4.1, OR = 2.6, respectively) then the prorated group but were almost half as likely to complete the dietary record at the 6-month postpartum visit (OR = 0.5). Survey completion at sixth visit was significantly higher for in-person versus online completion (68.6% vs. 93.1%). Findings suggest that remuneration schedule and data collection modality can impact completion of self- reported assessments.

Increased expression of proenkephalin and prodynorphin mRNAs in the nucleus accumbens of compulsive methamphetamine taking rats.

Addiction is associated with neuroadaptive changes in the brain. In the present paper, we used a model of methamphetamine self-administration during which we used footshocks to divide rats into animals that continue to press a lever to get methamphetamine (shock-resistant) and those that significantly reduce pressing the lever (shock-sensitive) despite the shocks. We trained male Sprague-Dawley rats to self-administer methamphetamine (0.1 mg/kg/infusion) for 9 hours daily for 20 days. Control group self-administered saline. Subsequently, methamphetamine self-administration rats were punished by mild electric footshocks for 10 days with gradual increases in shock intensity. Two hours after stopping behavioral experiments, we euthanized rats and isolated nucleus accumbens (NAc) samples. Affymetrix Array experiments revealed 24 differentially expressed genes between the shock-resistant and shock-sensitive rats, with 15 up- and 9 downregulated transcripts. Ingenuity pathway analysis showed that these transcripts belong to classes of genes involved in nervous system function, behavior, and disorders of the basal ganglia. These genes included prodynorphin (PDYN) and proenkephalin (PENK), among others. Because PDYN and PENK are expressed in dopamine D1- and D2-containing NAc neurons, respectively, these findings suggest that mechanisms, which impact both cell types may play a role in the regulation of compulsive methamphetamine taking by rats.