Microfluidics and multielectrode array-compatible organotypic slice culture method.

Organotypic brain slice cultures are used for a variety of molecular, electrophysiological, and imaging studies. However, the existing culture methods are difficult or expensive to apply in studies requiring long-term recordings with multielectrode arrays (MEAs). In this work, a novel method to maintain organotypic cultures of rodent hippocampus for several weeks on standard MEAs in an unmodified tissue culture incubator is described. Polydimethylsiloxane (Sylgard) mini-wells were used to stabilize organotypic cultures on glass and MEA surfaces. Hippocampus slices were successfully maintained within PDMS mini-wells for multiple weeks, with preserved pyramidal layer organization, connectivity, and activity. MEAs were used to record the development of spontaneous activity in an organotypic cultures for 4 weeks. This method is compatible with integration of microchannels into the culture substrate. Microchannels were incorporated into the mini-wells and applied to the guidance of axons originating within the slice, paving the way for studies of axonal sprouting using organotypic slices.

Cell-cell interaction modulates neuroectodermal specification of embryonic stem cells.

The controlled differentiation of embryonic stem (ES) cells is of utmost interest to their clinical, biotechnological, and basic science use. Many investigators have combinatorially assessed the role of specific soluble factors and extracellular matrices in guiding ES cell fate, yet the interaction between neighboring cells in these heterogeneous cultures has been poorly defined due to a lack of conventional tools to specifically uncouple these variables. Herein, we explored the role of cell-cell interactions during neuroectodermal specification of ES cells using a microfabricated cell pair array. We tracked differentiation events in situ, using an ES cell line expressing green fluorescent protein (GFP) under the regulation of the Sox1 gene promoter, an early marker of neuroectodermal germ cell commitment in the adult forebrain. We observed that a previously specified Sox1-GFP+ cell could induce the specification of an undifferentiated ES cell. This induction was modulated by the two cells being in contact and was dependent on the age of previously specified cell prior to coculture. A screen of candidate cell adhesion molecules revealed that the expression of connexin (Cx)-43 correlated with the age-dependent effect of cell contact in cell pair experiments. ES cells deficient in Cx-43 showed aberrant neuroectodermal specification and lineage commitment, highlighting the importance of gap junctional signaling in the development of this germ layer. Moreover, this study demonstrates the integration of microscale culture techniques to explore the biology of ES cells and gain insight into relevant developmental processes otherwise undefined due to bulk culture methods.

Clinical utility as a criterion for revising psychiatric diagnoses.

OBJECTIVE: Changes in DSM-IV were guided by empirical data that mostly focused on improving diagnostic validity and reliability. Although many changes were made explicitly to improve clinical utility, no formal effort was made to empirically determine actual improvements in clinical utility. The authors propose that future revisions of DSM empirically demonstrate improvement in clinical utility to clarify whether the advantages of changing the diagnostic criteria outweigh potential negative consequences. METHOD: The authors provide a formal definition of clinical utility and then suggest that the merits of a proposed change to DSM be evaluated by considering 1) its impact on the use of the diagnostic system, 2) whether it enhances clinical decision making, and 3) whether it improves clinical outcome. RESULTS: Evaluating a change based on its impact on use considers both user acceptability and accuracy in application of the diagnostic criteria. User acceptability can be measured by surveying users' reactions, assessing user acceptability in a field trial setting, and measuring the effects on ease of use. Assessment of the correct application of diagnostic criteria entails comparing the clinician's diagnostic assessment to expert diagnostic assessment. Assessments of the impact on clinical decision making use methods developed for evaluating adherence to practice guidelines. Improvement in outcome entails measuring reduction in symptom severity or improvement in functioning or in documenting the prevention of a future negative outcome. CONCLUSIONS: Empirical methods should be applied to the assessment of changes that purport to improve clinical utility in future revisions of DSM.

Clozapine inhibits isolated N-methyl-D-aspartate receptors expressed in xenopus oocytes in a subunit specific manner.

Antipsychotic agents have typically been viewed as acting through dopaminergic targets, although mounting evidence suggests that drugs such as clozapine may act on glutamatergic systems. In order to explore the effects of clozapine on the NMDA class of glutamate receptors, oocytes expressing the NMDA receptor NR1 subunit, coupled with different NR2 subunits, were exposed to clozapine and NMDA induced current was measured with two electrode voltage-clamp techniques. Our results indicate that clozapine inhibits the NMDA receptor, but that this inhibition is subunit specific, being significantly greater for receptors containing NR2A and NR2B than for those containing NR2C. Interestingly, the inhibition required pretreatment with clozapine before activation of the receptor with NMDA. In addition to providing mechanistic insights, this finding may help to explain divergent results in the literature regarding the effects of antipsychotic agents on glutamate receptors.

Environmental enrichment with nesting material accelerates wound healing in isolation-reared rats.

Early enrichment (EE) programs provide a well-established approach to mitigate the deleterious effects of childhood adversity. To better understand the therapeutic features of EE, in the current study we compared the effect of two forms of nesting material on isolation reared (IR) rats. We found that both materials, absent of social and any other physical enrichment, significantly improved wound healing rates. The results suggest that this animal model may provide useful insights into the critical components of EE.

Estradiol modulates medial prefrontal cortex and amygdala activity during fear extinction in women and female rats.

BACKGROUND: Men and women differ in their ability to extinguish fear. Fear extinction requires the activation of brain regions, including the ventromedial prefrontal cortex (vmPFC) and amygdala. Could estradiol modulate the activity of these brain regions during fear extinction? METHODS: All rat experiments were conducted in naturally cycling females. Rats underwent fear conditioning on Day 1. On Day 2, they underwent extinction training during the metestrus phase of the cycle (low estrogen and progesterone). Extinction recall was assessed on Day 3. Systemic injections of estrogen receptor-beta and -alpha agonists and of estradiol were administered at different time points to assess their influence on extinction consolidation and c-Fos expression in the vmPFC and amygdala. In parallel, healthy naturally cycling women underwent an analogous fear conditioning extinction training in a 3T functional magnetic resonance scanner. Measurement of their estradiol levels and skin conductance responses were obtained throughout the experiment. RESULTS: In female rats, administration of the estrogen-receptor beta (but not alpha) agonist facilitated extinction recall. Immediate (but not delayed) postextinction training administration of estradiol facilitated extinction memory consolidation and increased c-Fos expression in the vmPFC while reducing it in the amygdala. In parallel, natural variance in estradiol in premenopausal cycling women modulated vmPFC and amygdala reactivity and facilitated extinction recall. CONCLUSIONS: We provide translational evidence that demonstrates the influence of endogenous and exogenous estradiol on the fear extinction network. Our data suggest that women's endogenous hormonal status should be considered in future neurobiological research related to anxiety and mood disorders.

A randomized controlled trial of sertraline to prevent posttraumatic stress disorder in burned children.

BACKGROUND: This study evaluated the potential benefits of a centrally acting selective serotonin reuptake inhibitor, sertraline, versus placebo for prevention of symptoms of posttraumatic stress disorder (PTSD) and depression in burned children. This is the first controlled investigation based on our review of the early use of a medication to prevent PTSD in children. METHODS: Twenty-six children aged 6-20 were assessed in a 24-week double-blind placebo-controlled design. Each child received either flexibly dosed sertraline between 25-150 mg/day or placebo. At each reassessment, information was collected in compliance with the study medication, parental assessment of the child's symptomatology and functioning, and the child's self-report of symptomatology. The protocol was approved by the Human Studies Committees of Massachusetts General Hospital and Shriners Hospitals for Children. RESULTS: The final sample was 17 subjects who received sertraline versus 9 placebo control subjects matched for age, severity of injury, and type of hospitalization. There was no significant difference in change from baseline with child-reported symptoms; however, the sertraline group demonstrated a greater decrease in parent-reported symptoms over 8 weeks (-4.1 vs. -0.5, p=0.005), over 12 weeks (-4.4 vs. -1.2, p=.008), and over 24 weeks (-4.0 vs. -0.2, p=0.017). CONCLUSIONS: Sertraline was a safe drug, and it was somewhat more effective in preventing PTSD symptoms than placebo according to parent report but not child report. Based on this study, sertraline may prevent the emergence of PTSD symptoms in children.

Relaxation response-based yoga improves functioning in young children with autism: a pilot study.

OBJECTIVES: The study objectives were to develop and objectively assess the therapeutic effect of a novel movement-based complementary and alternative medicine approach for children with an autism-spectrum disorder (ASD). DESIGN: A within-subject analysis comparing pre- to post-treatment scores on two standard measures of childhood behavioral problems was used. SETTINGS AND LOCATION: The intervention and data analysis occurred at a tertiary care, medical school teaching hospital. SUBJECTS: Twenty-four (24) children aged 3-16 years with a diagnosis of an ASD comprised the study group. INTERVENTION: The efficacy of an 8-week multimodal yoga, dance, and music therapy program based on the relaxation response (RR) was developed and examined. OUTCOME MEASURES: The study outcome was measured using The Behavioral Assessment System for Children, Second Edition (BASC-2) and the Aberrant Behavioral Checklist (ABC). RESULTS: Robust changes were found on the BASC-2, primarily for 5-12-year-old children. Unexpectedly, the post-treatment scores on the Atypicality scale of the BASC-2, which measures some of the core features of autism, changed significantly (p=0.003). CONCLUSIONS: A movement-based, modified RR program, involving yoga and dance, showed efficacy in treating behavioral and some core features of autism, particularly for latency-age children.

Nest making and oxytocin comparably promote wound healing in isolation reared rats.

BACKGROUND: Environmental enrichment (EE) fosters attachment behavior through its effect on brain oxytocin levels in the hippocampus and other brain regions, which in turn modulate the hypothalamic-pituitary axis (HPA). Social isolation and other stressors negatively impact physical healing through their effect on the HPA. Therefore, we reasoned that: 1) provision of a rat EE (nest building with Nestlets) would improve wound healing in rats undergoing stress due to isolation rearing and 2) that oxytocin would have a similar beneficial effect on wound healing. METHODOLOGY/PRINCIPAL FINDINGS: In the first two experiments, we provided isolation reared rats with either EE or oxytocin and compared their wound healing to group reared rats and isolation reared rats that did not receive Nestlets or oxytocin. In the third experiment, we examined the effect of Nestlets on open field locomotion and immediate early gene (IEG) expression. We found that isolation reared rats treated with Nestlets a) healed significantly better than without Nestlets, 2) healed at a similar rate to rats treated with oxytocin, 3) had decreased hyperactivity in the open field test, and 4) had normalized IEG expression in brain hippocampus. CONCLUSIONS/SIGNIFICANCE: This study shows that when an EE strategy or oxytocin is given to isolation reared rats, the peripheral stress response, as measured by burn injury healing, is decreased. The findings indicate an association between the effect of nest making on wound healing and administration of the pro-bonding hormone oxytocin. Further elucidation of this animal model should lead to improved understanding of how EE strategies can ameliorate poor wound healing and other symptoms that result from isolation stress.

The good-enough mentoring relationship.

OBJECTIVE: This study aimed to describe the state of mentoring in today's academic environment. METHODS: Resident focus groups from across the nation discussed their opinions about mentoring and experiences with mentoring, and individual faculty members were videotaped discussing the same. RESULTS: Sixty-six residents and five faculty members participated in the project. There was consensus among residents and faculty regarding important qualities of a mentoring relationship, obstacles to forming a mentorship, and methods to improve the mentorship experience in psychiatric training. CONCLUSION: Mentoring is still believed to be a vital component of a successful residency experience. Specific components that warrant further research include boundaries within the relationship, ethnicity and gender factors, and potential need for resident and faculty curricula on the topic of mentoring.

Novel functional interactions between Trk kinase and p75 neurotrophin receptor in neuroblastoma cells.

To understand the functional interactions between the TrkA and p75 nerve growth factor (NGF) receptors, we stably transfected LAN5 neuroblastoma cells with an expression vector for ET-R, a chimeric receptor with the extracellular domain of the epidermal growth factor receptor (EGFR), and the TrkA transmembrane and intracellular domains. EGF activated the ET-R kinase and induced partial differentiation. NGF, which can bind to endogenous p75, did not induce differentiation but enhanced the EGF-induced response, leading to differentiation of almost all cells. A mutated NGF, 3T-NGF, that binds to TrkA but not to p75 did not synergize with EGF. Enhancement of EGF-induced differentiation required at least nanomolar concentrations of NGF, consistent with the low-affinity p75 binding site. EGF may induce a limited number of neuronal cells because it also enhanced apoptosis. Both NGF and a caspase inhibitor reduced apoptosis and, thereby, enhanced differentiation. NGF seems to enhance survival through the phosphatidylinositol-3 kinase (PI3K) pathway. Consistent with this hypothesis, Akt, a downstream effector of the PI3K pathway, was hyperphosphorylated in the presence of EGF+NGF. These results demonstrate that TrkA kinase initiates differentiation, and p75 enhances differentiation by rescuing differentiating cells from apoptosis via the PI3K pathway. Even though both EGF and NGF are required for differentiation of LAN5/ET-R cells, only NGF is required for survival of the differentiated cells. In the absence of NGF, the cells die by an apoptotic mechanism, involving caspase-3. An anti-p75 antibody blocked the survival effect of NGF. Brain-derived neurotrophic factor also enhanced cell survival, indicating that in differentiated cells, NGF acts through the p75 receptor to prevent apoptosis.