Lack of Z-DNA Conformation in Mitomycin-Modified Polynucleotides Having Inverted Circular Dichroism

Poly(dG-dC)· poly(dG-dC) and Micrococcus lysodeikticus DNA were modified by exposure to reductively activated mitomycin C, an antitumor antibiotic. The resulting covalent drug-polynucleotide complexes displayed varying degrees of CD inversions, which are strikingly similar to the inverted spectrum observed with Z-DNA. The following criteria have been used to establish, however, that the inverted CD pattern seen in mitomycin C-polynucleotide complexes does not reflect a Z-DNA conformation. (i) The ethanol-induced transition of poly(dG-dC)· poly(dG-dC) from B to Z conformation is not facilitated but rather is inhibited by mitomycin C modification. This may be due to the presence of crosslinks. (ii) Radioimmunoassay indicated no competition for Z-DNA-specific antibody by any of the mitomycin C-modified polynucleotides. (iii) 31P NMR of the complexes yielded a single relatively narrow resonance, which is inconsistent with the dinucleotide repeat characteristic of Z-DNA. Alternative explanations for the inverted CD pattern include a drug-induced left-handed but non-Z conformational change or the superposition of an induced CD onto the CD of B-DNA due to drug-base electronic interactions. These results illustrate the need for caution in interpreting CD changes alone as an indication of Z-DNA conformation

Structure of the Hsp110:Hsc70 nucleotide exchange machine.

Hsp70s mediate protein folding, translocation, and macromolecular complex remodeling reactions. Their activities are regulated by proteins that exchange ADP for ATP from the nucleotide-binding domain (NBD) of the Hsp70. These nucleotide exchange factors (NEFs) include the Hsp110s, which are themselves members of the Hsp70 family. We report the structure of an Hsp110:Hsc70 nucleotide exchange complex. The complex is characterized by extensive protein:protein interactions and symmetric bridging interactions between the nucleotides bound in each partner protein\u27s NBD. An electropositive pore allows nucleotides to enter and exit the complex. The role of nucleotides in complex formation and dissociation, and the effects of the protein:protein interactions on nucleotide exchange, can be understood in terms of the coupled effects of the nucleotides and protein:protein interactions on the open-closed isomerization of the NBDs. The symmetrical interactions in the complex may model other Hsp70 family heterodimers in which two Hsp70s reciprocally act as NEFs

Toward a client-centered benchmark for self-sufficiency: Evaluating the ‘process’ of becoming job ready.

The purpose of this study is to evaluate how service providers, clients, and graduates of a job training program define the term self-sufficiency (SS). This community-engaged, mixed method study qualitatively analyzes focus group data from each group and quantitatively examines survey data obtained from participants of the program. Findings reveal that psychological transformation as a ‘process’ represents the emic definition of SS—psychological SS—but each dimension of the concept is reflected in varying degrees by group. Provider and participant views are vastly different from the outcome-driven policy and funder definitions. Implications for benchmarking psychological SS as an empowerment-based ‘process’ measure of job readiness in workforce development evaluation are discussed

Optimal duration of risperidone or olanzapine adjunctive therapy to mood stabilizer following remission of a manic episode: A CANMAT randomized double-blind trial

Atypical antipsychotic adjunctive therapy to lithium or valproate is effective in treating acute mania. Although continuation of atypical antipsychotic adjunctive therapy after mania remission reduces relapse of mood episodes, the optimal duration is unknown. As many atypical antipsychotics cause weight gain and metabolic syndrome, they should not be continued unless the benefits outweigh the risks. This 52-week double-blind placebo-controlled trial recruited patients with bipolar I disorder (n=159) who recently remitted from a manic episode during treatment with risperidone or olanzapine adjunctive therapy to lithium or valproate. Patients were randomized to one of three conditions: discontinuation of risperidone or olanzapine and substitution with placebo at (i) entry (\u270-weeks\u27 group) or (ii) at 24 weeks after entry (\u2724-weeks\u27 group) or (iii) continuation of risperidone or olanzapine for the full duration of the study (\u2752-weeks\u27 group). The primary outcome measure was time to relapse of any mood episode. Compared with the 0-weeks group, the time to any mood episode was significantly longer in the 24-weeks group (hazard ratio (HR) 0.53; 95% confidence interval (CI): 0.33, 0.86) and nearly so in the 52-weeks group (HR: 0.63; 95% CI: 0.39, 1.02). The relapse rate was similar in the 52-weeks group compared with the 24-weeks group (HR: 1.18; 95% CI: 0.71, 1.99); however, sub-group analysis showed discordant results between the two antipsychotics (HR: 0.48, 95% CI: 0.17; 1.32 olanzapine patients; HR: 1.85, 95% CI: 1.00, 3.41 risperidone patients). Average weight gain was 3.2 kg in the 52-weeks group compared with a weight loss of 0.2 kg in the 0-weeks and 0.1 kg in the 24-weeks groups. These findings suggest that risperidone or olanzapine adjunctive therapy for 24 weeks is beneficial but continuation of risperidone beyond this period does not reduce the risk of relapse. Whether continuation of olanzapine beyond this period reduces relapse risk remains unclear but the potential benefit needs to be weighed against an increased risk of weight gain

Influence of birth cohort on age of onset cluster analysis in bipolar I disorder

PURPOSE: Two common approaches to identify subgroups of patients with bipolar disorder are clustering methodology (mixture analysis) based on the age of onset, and a birth cohort analysis. This study investigates if a birth cohort effect will influence the results of clustering on the age of onset, using a large, international database. METHODS: The database includes 4037 patients with a diagnosis of bipolar I disorder, previously collected at 36 collection sites in 23 countries. Generalized estimating equations (GEE) were used to adjust the data for country median age, and in some models, birth cohort. Model-based clustering (mixture analysis) was then performed on the age of onset data using the residuals. Clinical variables in subgroups were compared. RESULTS: There was a strong birth cohort effect. Without adjusting for the birth cohort, three subgroups were found by clustering. After adjusting for the birth cohort or when considering only those born after 1959, two subgroups were found. With results of either two or three subgroups, the youngest subgroup was more likely to have a family history of mood disorders and a first episode with depressed polarity. However, without adjusting for birth cohort (three subgroups), family history and polarity of the first episode could not be distinguished between the middle and oldest subgroups. CONCLUSION: These results using international data confirm prior findings using single country data, that there are subgroups of bipolar I disorder based on the age of onset, and that there is a birth cohort effect. Including the birth cohort adjustment altered the number and characteristics of subgroups detected when clustering by age of onset. Further investigation is needed to determine if combining both approaches will identify subgroups that are more useful for research

‘Fractional Recovery’ Analysis of a Presynaptic Synaptotagmin 1-Anchored Endocytic Protein Complex

BACKGROUND: The integral synaptic vesicle protein and putative calcium sensor, synaptotagmin 1 (STG), has also been implicated in synaptic vesicle (SV) recovery. However, proteins with which STG interacts during SV endocytosis remain poorly understood. We have isolated an STG-associated endocytic complex (SAE) from presynaptic nerve terminals and have used a novel fractional recovery (FR) assay based on electrostatic dissociation to identify SAE components and map the complex structure. The location of SAE in the presynaptic terminal was determined by high-resolution quantitative immunocytochemistry at the chick ciliary ganglion giant calyx-type synapse. METHODOLOGY/PRINCIPLE FINDINGS: The first step in FR analysis was to immunoprecipitate (IP) the complex with an antibody against one protein component (the IP-protein). The immobilized complex was then exposed to a high salt (1150 mM) stress-test that caused shedding of co-immunoprecipitated proteins (co-IP-proteins). A Fractional Recovery ratio (FR: recovery after high salt/recovery with control salt as assayed by Western blot) was calculated for each co-IP-protein. These FR values reflect complex structure since an easily dissociated protein, with a low FR value, cannot be intermediary between the IP-protein and a salt-resistant protein. The structure of the complex was mapped and a blueprint generated with a pair of FR analyses generated using two different IP-proteins. The blueprint of SAE contains an AP180/X/STG/stonin 2/intersectin/epsin core (X is unknown and epsin is hypothesized), and an AP2 adaptor, H-/L-clathrin coat and dynamin scission protein perimeter. Quantitative immunocytochemistry (ICA/ICQ method) at an isolated calyx-type presynaptic terminal indicates that this complex is associated with STG at the presynaptic transmitter release face but not with STG on intracellular synaptic vesicles. CONCLUSIONS/SIGNIFICANCE: We hypothesize that the SAE serves as a recognition site and also as a seed complex for clathrin-mediated synaptic vesicle recovery. The combination of FR analysis with quantitative immunocytochemistry provides a novel and effective strategy for the identification and characterization of biologically-relevant multi-molecular complexes

What we learn about bipolar disorder from large-scale neuroimaging: Findings and future directions from theENIGMABipolar Disorder Working Group

MRI‐derived brain measures offer a link between genes, the environment and behavior and have been widely studied in bipolar disorder (BD). However, many neuroimaging studies of BD have been underpowered, leading to varied results and uncertainty regarding effects. The Enhancing Neuro Imaging Genetics through Meta‐Analysis (ENIGMA) Bipolar Disorder Working Group was formed in 2012 to empower discoveries, generate consensus findings and inform future hypothesis‐driven studies of BD. Through this effort, over 150 researchers from 20 countries and 55 institutions pool data and resources to produce the largest neuroimaging studies of BD ever conducted. The ENIGMA Bipolar Disorder Working Group applies standardized processing and analysis techniques to empower large‐scale meta‐ and mega‐analyses of multimodal brain MRI and improve the replicability of studies relating brain variation to clinical and genetic data. Initial BD Working Group studies reveal widespread patterns of lower cortical thickness, subcortical volume and disrupted white matter integrity associated with BD. Findings also include mapping brain alterations of common medications like lithium, symptom patterns and clinical risk profiles and have provided further insights into the pathophysiological mechanisms of BD. Here we discuss key findings from the BD working group, its ongoing projects and future directions for large‐scale, collaborative studies of mental illness