Desensitization of NMDA receptor channels is modulated by glutamate agonists.

Two distinct forms of desensitization have been characterized for N-methyl-D-aspartate (NMDA) receptors. One form results from a weakening of agonist affinity when channels are activated whereas the other form of desensitization results when channels enter a long-lived nonconducting state. A weakening of glycine affinity upon NMDA receptor activation has been reported. Cyclic reaction schemes for NMDA receptor activation require that a concomitant affinity shift should be observed for glutamate agonists. In this study, measurements of peak and steady-state NMDA receptor currents yielded EC50 values for glutamate that differed by 1.9-fold, but no differences were found for another agonist, L-cysteine-S-sulfate (LCSS). Simulations show that shifts in EC50 values may be masked by significant degrees of desensitization resulting from channels entering a long-lived nonconducting state. Simulations also show that a decrease in the degree of desensitization with increasing agonist concentration is a good indicator for the existence of desensitization resulting from a weakening of agonist affinity. Both glutamate and LCSS exhibited this trend. An affinity difference of three- to eightfold between high-and low-affinity agonist-binding states was estimated from fitting of dose-response data with models containing both types of desensitization. This indicates that activation of NMDA receptors causes a reduction in both glutamate and glycine affinities

Measurement of [18F]-fluorodeoxyglucose incorporation into human osteoblast–An experimental method

An evaluation of human osteoblast metabolism usually involves measurements of the by-products of bone matrix elaboration. The assessment of glycolytic activity of osteoblasts is not a standard tool in most of the reports, but might be of value by providing a direct indicator of cellular metabolism. Measurement of the incorporation of [18F]-fluorodeoxyglucose, which is not further degradable following its conversion into glycose-6-phosphate during glycolysis and is trapped in this form within the cells, can be used as an effective research tool for estimation of osteoblast metabolism. In order to estimate the [18F]-fluorodeoxyglucose incorporation we used cultured human osteoblast-like cells. Following incubation of the culture samples in a glucose free medium with 5 μ Ci [18F]-fluorodeoxyglucose we measured the radioactivity of the cell fraction, as a percent from the initial dose, and compared to the incorporation values in cells treated by protoporphyrine IX (10−5 M), an endogenous pro-apoptotic agent. To compare the response of [18F]-fluorodeoxyglucose incorporation studies, following treatment of cells with the protoporphyrine IX, to other experimental cell metabolism evaluation methods, we performed a parallel comparison of alkaline phospatase activity, which is a standard measurement tool of osteoblast metabolism, in the control and treatment groups. A narrow range of 0.22–1.36% of [18F]-fluorodeoxyglucose incorporation per million cells was found. Additionally in the protoporphyrine IX treated cells a significant 62% decrease of [18F]-fluorodeoxyglucose incorporation was observed (p < .05). A parallel significant decrease in alkaline phosphatase activity (p < .001) was found in the cells treated by the protoporphyrine IX. Therefore we suggest that the presented method of [18F]-fluorodeoxyglucose incorporation measurement can be utilized as an effective research tool for estimation of the cellular glycolitic activity in human osteoblast-like cells in vitro

Implementation research for public sector mental health care scale-up (SMART-DAPPER): a sequential multiple, assignment randomized trial (SMART) of non-specialist-delivered psychotherapy and/or medication for major depressive disorder and posttraumatic stress disorder (DAPPER) integrated with outpatient care clinics at a county hospital in Kenya.

BackgroundMental disorders are a leading cause of global disability, driven primarily by depression and anxiety. Most of the disease burden is in Low and Middle Income Countries (LMICs), where 75% of adults with mental disorders have no service access. Our research team has worked in western Kenya for nearly ten years. Primary care populations in Kenya have high prevalence of Major Depressive Disorder (MDD) and Posttraumatic Stress Disorder (PTSD). To address these treatment needs with a sustainable, scalable mental health care strategy, we are partnering with local and national mental health stakeholders in Kenya and Uganda to identify 1) evidence-based strategies for first-line and second-line treatment delivered by non-specialists integrated with primary care, 2) investigate presumed mediators of treatment outcome and 3) determine patient-level moderators of treatment effect to inform personalized, resource-efficient, non-specialist treatments and sequencing, with costing analyses. Our implementation approach is guided by the Exploration, Preparation, Implementation, Sustainment (EPIS) framework.Methods/designWe will use a Sequential, Multiple Assignment Randomized Trial (SMART) to randomize 2710 patients from the outpatient clinics at Kisumu County Hospital (KCH) who have MDD, PTSD or both to either 12 weekly sessions of non-specialist-delivered Interpersonal Psychotherapy (IPT) or to 6 months of fluoxetine prescribed by a nurse or clinical officer. Participants who are not in remission at the conclusion of treatment will be re-randomized to receive the other treatment (IPT receives fluoxetine and vice versa) or to combination treatment (IPT and fluoxetine). The SMART-DAPPER Implementation Resource Team, (IRT) will drive the application of the EPIS model and adaptations during the course of the study to optimize the relevance of the data for generalizability and scale -up.DiscussionThe results of this research will be significant in three ways: 1) they will determine the effectiveness of non-specialist delivered first- and second-line treatment for MDD and/or PTSD, 2) they will investigate key mechanisms of action for each treatment and 3) they will produce tailored adaptive treatment strategies essential for optimal sequencing of treatment for MDD and/or PTSD in low resource settings with associated cost information - a critical gap for addressing a leading global cause of disability.Trial registrationClinicalTrials.gov NCT03466346, registered March 15, 2018

Implementation research for public sector mental health care scale-up (SMART-DAPPER): a sequential multiple, assignment randomized trial (SMART) of non-specialist-delivered psychotherapy and/or medication for major depressive disorder and posttraumatic stress disorder (DAPPER) integrated with outpatient care clinics at a county hospital in Kenya

Abstract Background Mental disorders are a leading cause of global disability, driven primarily by depression and anxiety. Most of the disease burden is in Low and Middle Income Countries (LMICs), where 75% of adults with mental disorders have no service access. Our research team has worked in western Kenya for nearly ten years. Primary care populations in Kenya have high prevalence of Major Depressive Disorder (MDD) and Posttraumatic Stress Disorder (PTSD). To address these treatment needs with a sustainable, scalable mental health care strategy, we are partnering with local and national mental health stakeholders in Kenya and Uganda to identify 1) evidence-based strategies for first-line and second-line treatment delivered by non-specialists integrated with primary care, 2) investigate presumed mediators of treatment outcome and 3) determine patient-level moderators of treatment effect to inform personalized, resource-efficient, non-specialist treatments and sequencing, with costing analyses. Our implementation approach is guided by the Exploration, Preparation, Implementation, Sustainment (EPIS) framework. Methods/design We will use a Sequential, Multiple Assignment Randomized Trial (SMART) to randomize 2710 patients from the outpatient clinics at Kisumu County Hospital (KCH) who have MDD, PTSD or both to either 12 weekly sessions of non-specialist-delivered Interpersonal Psychotherapy (IPT) or to 6 months of fluoxetine prescribed by a nurse or clinical officer. Participants who are not in remission at the conclusion of treatment will be re-randomized to receive the other treatment (IPT receives fluoxetine and vice versa) or to combination treatment (IPT and fluoxetine). The SMART-DAPPER Implementation Resource Team, (IRT) will drive the application of the EPIS model and adaptations during the course of the study to optimize the relevance of the data for generalizability and scale –up. Discussion The results of this research will be significant in three ways: 1) they will determine the effectiveness of non-specialist delivered first- and second-line treatment for MDD and/or PTSD, 2) they will investigate key mechanisms of action for each treatment and 3) they will produce tailored adaptive treatment strategies essential for optimal sequencing of treatment for MDD and/or PTSD in low resource settings with associated cost information – a critical gap for addressing a leading global cause of disability. Trial registration ClinicalTrials.gov NCT03466346 , registered March 15, 2018.http://deepblue.lib.umich.edu/bitstream/2027.42/173667/1/12888_2019_Article_2395.pd