Using the Chick Embryo Brain as a Model for In Vivo and Ex Vivo Analyses of Human Glioblastoma Cell Behavior.

The chick embryo has been an ideal model system for the study of vertebrate development, particularly for experimental manipulations. Use of the chick embryo has been extended for studying the formation of human glioblastoma (GBM) brain tumors in vivo and the invasiveness of tumor cells into surrounding brain tissue. GBM tumors can be formed by injection of a suspension of fluorescently labeled cells into the E5 midbrain (optic tectum) ventricle in ovo. Depending on the GBM cells, compact tumors randomly form in the ventricle and within the brain wall, and groups of cells invade the brain wall tissue. Thick tissue sections (350 µm) of fixed E15 tecta with tumors can be immunostained to reveal that invading cells often migrate along blood vessels when analyzed by 3D reconstruction of confocal z-stack images. Live E15 midbrain and forebrain slices (250-350 µm) can be cultured on membrane inserts, where fluorescently labeled GBM cells can be introduced into non-random locations to provide ex vivo co-cultures to analyze cell invasion, which also can occur along blood vessels, over a period of about 1 week. These ex vivo co-cultures can be monitored by widefield or confocal fluorescence time-lapse microscopy to observe live cell behavior. Co-cultured slices then can be fixed, immunostained, and analyzed by confocal microscopy to determine whether or not the invasion occurred along blood vessels or axons. Additionally, the co-culture system can be used for investigating potential cell-cell interactions by placing aggregates of different cell types and colors in different precise locations and observing cell movements. Drug treatments can be performed on ex vivo cultures, whereas these treatments are not compatible with the in ovo system. These two complementary approaches allow for detailed and precise analyses of human GBM cell behavior and tumor formation in a highly manipulatable vertebrate brain environment.

Skills to Enhance Positivity in adolescents at risk for suicide: Protocol for a randomized controlled trial.

BACKGROUND: Suicide and suicidal behavior during adolescence have been steadily increasing over the past two decades. The preponderance of interventions focuses on crisis intervention, underlying psychiatric disorders, regulating negative affect, and reducing cognitive distortions. However, low positive affectivity may be a mechanism that contributes to adolescent suicidal ideation and behaviors independent of other risk factors. Skills to Enhance Positivity (STEP) is an acceptance-based intervention, designed to increase attention to, and awareness of, positive affect and positive experiences. Results from a pilot RCT demonstrated engagement of the target (positive affect) and a decrease in clinical outcomes (suicidal events; i.e., either a suicide attempt or an emergency intervention for an acute suicidal crisis), providing support to test the clinical effectiveness of STEP in a larger clinical trial with clinical staff implementing the intervention. OBJECTIVE: To test the effectiveness of STEP, compared to Enhanced Treatment as Usual (ETAU), in reducing suicidal events and ideation in adolescents admitted to inpatient psychiatric care due to suicide risk. We hypothesize that those randomized to STEP, compared to ETAU, will have lower rates of suicide events, active suicidal ideation (SI), and depressed mood over the 6-month follow-up period. We hypothesize that those randomized to STEP, compared to ETAU, will demonstrate greater improvement in the hypothesized mechanisms of attention to positive affect stimuli and gratitude and satisfaction with life. METHODS: Participants will be randomized to either STEP or ETAU. STEP consists of four in-person sessions focused on psychoeducation regarding positive and negative affect, mindfulness meditation, gratitude, and savoring. Mood monitoring prompts and skill reminders will be sent via text messaging daily for the first month post-discharge and every other day for the following two months. The ETAU condition will receive text-delivered reminders to use a safety plan provided at discharge from the hospital and healthy habits messages, matched in frequency to the STEP group. This trial was registered on 6 August 2021 (ClinicalTrials.gov NCT04994873). RESULTS: The STEP protocol was approved by the National Institute of Mental Health (NIMH) Data and Safety Monitoring Board on March 4, 2022. The RCT is currently in progress. DISCUSSION: The STEP protocol is an innovative, adjunctive treatment that has the potential to have positive effects on adolescent suicidal ideation and attempts beyond that found for standard treatment alone.