Gene Expression Profiling of Two Distinct Neuronal Populations in the Rodent Spinal Cord

BACKGROUND: In the field of neuroscience microarray gene expression profiles on anatomically defined brain structures are being used increasingly to study both normal brain functions as well as pathological states. Fluorescent tracing techniques in brain tissue that identifies distinct neuronal populations can in combination with global gene expression profiling potentially increase the resolution and specificity of such studies to shed new light on neuronal functions at the cellular level. METHODOLOGY/PRINCIPAL FINDINGS: We examine the microarray gene expression profiles of two distinct neuronal populations in the spinal cord of the neonatal rat, the principal motor neurons and specific interneurons involved in motor control. The gene expression profiles of the respective cell populations were obtained from amplified mRNA originating from 50-250 fluorescently identified and laser microdissected cells. In the data analysis we combine a new microarray normalization procedure with a conglomerate measure of significant differential gene expression. Using our methodology we find 32 genes to be more expressed in the interneurons compared to the motor neurons that all except one have not previously been associated with this neuronal population. As a validation of our method we find 17 genes to be more expressed in the motor neurons than in the interneurons and of these only one had not previously been described in this population. CONCLUSIONS/SIGNIFICANCE: We provide an optimized experimental protocol that allows isolation of gene transcripts from fluorescent retrogradely labeled cell populations in fresh tissue, which can be used to generate amplified aRNA for microarray hybridization from as few as 50 laser microdissected cells. Using this optimized experimental protocol in combination with our microarray analysis methodology we find 49 differentially expressed genes between the motor neurons and the interneurons that reflect the functional differences between these two cell populations in generating and transmitting the motor output in the rodent spinal cord

Interest in an Online Smoking Cessation Program and Effective Recruitment Strategies: Results From Project Quit

Reviewer: Swartz, LReviewer: Rabius, V[This item is a preserved copy and is not necessarily the most recent version. To view the current item, visit http://www.jmir.org/2006/3/e14/]Background: The Internet is a promising venue for delivering smoking cessation treatment, either as a stand-alone program or as an adjunct to pharmacotherapy. However, there is little data to indicate what percent of smokers are interested in receiving online smoking cessation services or how best to recruit smokers to Internet-based programs. Objective: Using a defined recruitment sample, this study aimed to identify the percentage of smokers who expressed interest in or enrolled in Project Quit, a tailored, online, cognitive-behavioral support program offered with adjunctive nicotine replacement therapy patches. In addition, we examined the effectiveness of several individual-level versus population-level recruitment strategies. Methods: Members from two large health care organizations in the United States were invited to participate in Project Quit. Recruitment efforts included proactive invitation letters mailed to 34533 likely smokers and reactive population-level study advertisements targeted to all health plan members (> 560000 adults, including an estimated 98000 smokers across both health care organizations). Results: An estimated 1.6% and 2.5% of adult smokers from each health care organization enrolled in Project Quit. Among likely smokers who received proactive study invitations, 7% visited the Project Quit website (n = 2260) and 4% (n = 1273) were eligible and enrolled. Response rates were similar across sites, despite using different sources to assemble the invitation mailing list. Proactive individual-level recruitment was more effective than other forms of recruitment, accounting for 69% of website visitors and 68% of enrollees. Conclusions: Smokers were interested in receiving online smoking cessation support, even though they had access to other forms of treatment through their health insurance. Uptake rates for this program were comparable to those seen when smokers are advised to quit and are referred to other forms of smoking cessation treatment. In this sample, proactive mailings were the best method for recruiting smokers to Project Quit