Modulation of anxiety by cortical serotonin 1A receptors

Attempts to generate reliable and versatile vectors for gene therapy and biomedical research that express multiple genes have met with limited success. Here we used Picornavirus 'self-cleaving' 2A peptides, or 2A-like sequences from other viruses, to generate multicistronic retroviral vectors with efficient translation of four cistrons. Using the T-cell receptor:CD3 complex as a test system, we show that a single 2A peptide-linked retroviral vector can be used to generate all four CD3 proteins (CD3epsilon, gamma, delta, zeta), and restore T-cell development and function in CD3-deficient mice. We also show complete 2A peptide-mediated 'cleavage' and stoichiometric production of two fluorescent proteins using a fluorescence resonance energy transfer-based system in multiple cell types including blood, thymus, spleen, bone marrow and early stem cell progenitors.

As conditional genetic strategies advance, the need for multiple site-specific recombinase systems has emerged. To meet this need in part, we have targeted the constitutive ROSA26 locus to create a mouse strain with generalized expression of the enhanced version of the site-specific recombinase FLP (FLPe). This strain is designated FLPeR ("flipper"). Using this strain, extensive target gene recombination can be achieved in most tissue types, including cells of the developing germ line. FLPeR mice therefore serve two important functions: as a source of many different FLPe-expressing primary cell lines and as a deleter strain. Moreover, because the FLPeR mouse is a 129-derived strain, a 129 genetic background can be preserved when crossed to most ES cell-derived mice. This enables conditional genetic alterations to be maintained on a standard background, a feature important for obtaining reproducible results and genetically defined controls.

Although clinicians frequently add a second medication to an initial, ineffective antidepressant drug, no randomized controlled trial has compared the efficacy of this approach. We randomly assigned 565 adult outpatients who had nonpsychotic major depressive disorder without remission despite a mean of 11.9 weeks of citalopram therapy (mean final dose, 55 mg per day) to receive sustained-release bupropion (at a dose of up to 400 mg per day) as augmentation and 286 to receive buspirone (at a dose of up to 60 mg per day) as augmentation. The primary outcome of remission of symptoms was defined as a score of 7 or less on the 17-item Hamilton Rating Scale for Depression (HRSD-17) at the end of this study; scores were obtained over the telephone by raters blinded to treatment assignment. The 16-item Quick Inventory of Depressive Symptomatology--Self-Report (QIDS-SR-16) was used to determine the secondary outcomes of remission (defined as a score of less than 6 at the end of this study) and response (a reduction in baseline scores of 50 percent or more). The sustained-release bupropion group and the buspirone group had similar rates of HRSD-17 remission (29.7 percent and 30.1 percent, respectively), QIDS-SR-16 remission (39.0 percent and 32.9 percent), and QIDS-SR-16 response (31.8 percent and 26.9 percent). Sustained-release bupropion, however, was associated with a greater reduction (from baseline to the end of this study) in QIDS-SR-16 scores than was buspirone (25.3 percent vs. 17.1 percent, P<0.04), a lower QIDS-SR-16 score at the end of this study (8.0 vs. 9.1, P<0.02), and a lower dropout rate due to intolerance (12.5 percent vs. 20.6 percent, P<0.009). Augmentation of citalopram with either sustained-release bupropion or buspirone appears to be useful in actual clinical settings. Augmentation with sustained-release bupropion does have certain advantages, including a greater reduction in the number and severity of symptoms and fewer side effects and adverse events. (ClinicalTrials.gov number, NCT00021528.). Copyright 2006 Massachusetts Medical Society.