Quantitative Multicolor Compositional Imaging Resolves Molecular Domains in Cell-Matrix Adhesions

Background: Cellular processes occur within dynamic and multi-molecular compartments whose characterization requires analysis at high spatio-temporal resolution. Notable examples for such complexes are cell-matrix adhesion sites, consisting of numerous cytoskeletal and signaling proteins. These adhesions are highly variable in their morphology, dynamics, and apparent function, yet their molecular diversity is poorly defined. Methodology/Principal Findings: We present here a compositional imaging approach for the analysis and display of multicomponent compositions. This methodology is based on microscopy-acquired multicolor data, multi-dimensional clustering of pixels according to their composition similarity and display of the cellular distribution of these composition clusters. We apply this approach for resolving the molecular complexes associated with focal-adhesions, and the time-dependent effects of Rho-kinase inhibition. We show here compositional variations between adhesion sites, as well as ordered variations along the axis of individual focal-adhesions. The multicolor clustering approach also reveals distinct sensitivities of different focaladhesion-associated complexes to Rho-kinase inhibition. Conclusions/Significance: Multicolor compositional imaging resolves ‘‘molecular signatures’ ’ characteristic to focaladhesions and related structures, as well as sub-domains within these adhesion sites. This analysis enhances the spatial information with additional ‘‘contents-resolved’ ’ dimensions. We propose that compositional imaging can serve as

Current treatment options for recurrent nasopharyngeal cancer

Loco-regional control rate of nasopharyngeal carcinoma (NPC) has improved significantly in the past decade. However, local recurrence still represents a major cause of mortality and morbidity in advanced stages, and management of local failure remains a challenging issue in NPC. The best salvage treatment for local recurrent NPC remains to be determined. The options include brachytherapy, external radiotherapy, stereotactic radiosurgery, and nasopharyngectomy, either alone or in different combinations. In this article we will discuss the different options for salvage of locally recurrent NPC. Retreatment of locally recurrent NPC using radiotherapy, alone or in combination with other treatment modalities, as well as surgery, can result in long-term local control and survival in a substantial proportion of patients. For small-volume recurrent tumors (T1–T2) treated with external radiotherapy, brachytherapy or stereotactic radiosurgery, comparable results to those obtained with surgery have been reported. In contrast, treatment results of advanced-stage locally recurrent NPC are generally more satisfactory with surgery (with or without postoperative radiotherapy) than with reirradiation

Interaction between Hydrogenase Maturation Factors HypA and HypB Is Required for [NiFe]-Hydrogenase Maturation

The active site of [NiFe]-hydrogenase contains nickel and iron coordinated by cysteine residues, cyanide and carbon monoxide. Metal chaperone proteins HypA and HypB are required for the nickel insertion step of [NiFe]-hydrogenase maturation. How HypA and HypB work together to deliver nickel to the catalytic core remains elusive. Here we demonstrated that HypA and HypB from Archaeoglobus fulgidus form 1∶1 heterodimer in solution and HypA does not interact with HypB dimer preloaded with GMPPNP and Ni. Based on the crystal structure of A. fulgidus HypB, mutants were designed to map the HypA binding site on HypB. Our results showed that two conserved residues, Tyr-4 and Leu-6, of A. fulgidus HypB are required for the interaction with HypA. Consistent with this observation, we demonstrated that the corresponding residues, Leu-78 and Val-80, located at the N-terminus of the GTPase domain of Escherichia coli HypB were required for HypA/HypB interaction. We further showed that L78A and V80A mutants of HypB failed to reactivate hydrogenase in an E. coli ΔhypB strain. Our results suggest that the formation of the HypA/HypB complex is essential to the maturation process of hydrogenase. The HypA binding site is in proximity to the metal binding site of HypB, suggesting that the HypA/HypB interaction may facilitate nickel transfer between the two proteins

Pneumonia and poverty: a prospective population-based study among children in Brazil

<p>Abstract</p> <p>Background</p> <p>Children in developing country suffer the highest burden of pneumonia. However, few studies have evaluated associations between poverty and pneumonia.</p> <p>Methods</p> <p>A prospective population-based study on pneumonia was carried out as part of the Latin America Epidemiological Assessment of Pneumococcus (LEAP study). Chest x-rays were obtained for children one to 35 months old with suspected pneumonia presenting to emergency care centers and hospital emergency rooms in Goiania, Brazil. Chest radiographs were evaluated according to WHO guidelines. Clustering of radiologically-confirmed pneumonia were evaluated using a Poisson-based spatial scan statistic. Associations between census socioeconomic indicators and pneumonia incidence rates were analyzed using generalized linear models.</p> <p>Results</p> <p>From May, 2007 to May, 2009, chest radiographs were obtained from 11 521 children with clinical pneumonia; 3955 episodes were classified as radiologically-confirmed. Incidence rates were significantly higher in very low income areas (4825.2 per 10⁵) compared to high income areas (1637.3 per 10⁵). Spatial analysis identified clustering of confirmed pneumonia in Western (RR 1.78; p = 0.001) and Southeast (RR 1.46; p = 0.001) regions of the city, and clustering of hospitalized pneumonia in the Western region (RR 1.69; p = 0.001). Lower income households and illiteracy were associated with pneumonia incidence.</p> <p>Conclusions</p> <p>In infants the risk of developing pneumonia is inversely associated with the head of household income and with the woman educational level. Areas with deprived socioeconomic conditions had higher incidence of pneumonia and should be targeted for high vaccination coverage.</p

Can Molecular Motors Drive Distance Measurements in Injured Neurons?

Injury to nerve axons induces diverse responses in neuronal cell bodies, some of which are influenced by the distance from the site of injury. This suggests that neurons have the capacity to estimate the distance of the injury site from their cell body. Recent work has shown that the molecular motor dynein transports importin-mediated retrograde signaling complexes from axonal lesion sites to cell bodies, raising the question whether dynein-based mechanisms enable axonal distance estimations in injured neurons? We used computer simulations to examine mechanisms that may provide nerve cells with dynein-dependent distance assessment capabilities. A multiple-signals model was postulated based on the time delay between the arrival of two or more signals produced at the site of injury–a rapid signal carried by action potentials or similar mechanisms and slower signals carried by dynein. The time delay between the arrivals of these two types of signals should reflect the distance traversed, and simulations of this model show that it can indeed provide a basis for distance measurements in the context of nerve injuries. The analyses indicate that the suggested mechanism can allow nerve cells to discriminate between distances differing by 10% or more of their total axon length, and suggest that dynein-based retrograde signaling in neurons can be utilized for this purpose over different scales of nerves and organisms. Moreover, such a mechanism might also function in synapse to nucleus signaling in uninjured neurons. This could potentially allow a neuron to dynamically sense the relative lengths of its processes on an ongoing basis, enabling appropriate metabolic output from cell body to processes

Aberrant overexpression of membrane-associated mucin contributes to tumor progression in adult T-cell leukemia/lymphoma cells.

Aberrant overexpression of membrane-associated mucin (MUC1) is implicated in the pathogenesis of cancer, particularly of adenocarcinomas. Adult T-cell leukemia/lymphoma (ATL), an aggressive neoplasm etiologically associated with human T-lymphotropic virus type-1 (HTLV-1), exhibits invasive tropism into various organs, resulting in disease progression and resistance to treatment. In the present study, we showed that MUC1 is overexpressed exclusively in cells of ATL among hematological malignancies. Furthermore, increased expression of MUC1 correlated with a poor prognosis, suggesting MUC1 to be a prognostic marker in ATL. Various functional analyses with knockdown experiments using a specific siRNA for MUC1 revealed that MUC1 is involved in cell growth, cell aggregation, and resistance to apoptosis. Although it has been shown that the anti-adhesive properties of MUC1 facilitate migration and metastasis of tumor cells, our findings indicated that MUC1 contributes to cell-cell adhesion. Mucins thus seem to play a role in the pathogenesis and/or progression of ATL

Structural Basis for GTP-Dependent Dimerization of Hydrogenase Maturation Factor HypB

Maturation of [NiFe]-hydrogenase requires the insertion of iron, cyanide and carbon monoxide, followed by nickel, to the catalytic core of the enzyme. Hydrogenase maturation factor HypB is a metal-binding GTPase that is essential for the nickel delivery to the hydrogenase. Here we report the crystal structure of Archeoglobus fulgidus HypB (AfHypB) in apo-form. We showed that AfHypB recognizes guanine nucleotide using Asp-194 on the G5 loop despite having a non-canonical NKxA G4-motif. Structural comparison with the GTPγS-bound Methanocaldococcus jannaschii HypB identifies conformational changes in the switch I region, which bring an invariant Asp-72 to form an intermolecular salt-bridge with another invariant residue Lys-148 upon GTP binding. Substitution of K148A abolished GTP-dependent dimerization of AfHypB, but had no significant effect on the guanine nucleotide binding and on the intrinsic GTPase activity. In vivo complementation study in Escherichia coli showed that the invariant lysine residue is required for in vivo maturation of hydrogenase. Taken together, our results suggest that GTP-dependent dimerization of HypB is essential for hydrogenase maturation. It is likely that a nickel ion is loaded to an extra metal binding site at the dimeric interface of GTP-bound HypB and transferred to the hydrogenase upon GTP hydrolysis

Effectiveness of the universal prevention program 'Healthy School and Drugs': Study protocol of a randomized clustered trial

Contains fulltext : 90260.pdf (publisher's version ) (Open Access)Background: Substance use is highly prevalent among Dutch adolescents. The Healthy School and Drugs program is a nationally implemented school-based prevention program aimed at reducing early and excessive substance use among adolescents. Although the program's effectiveness was tested in a quasi-experimental design before, many program changes were made afterwards. The present study, therefore, aims to test the effects of this widely used, renewed universal prevention program. Methods/Design: A randomized clustered trial will be conducted among 3,784 adolescents of 23 secondary schools in The Netherlands. The trial has three conditions; two intervention conditions (i.e., e-learning and integral) and a control condition. The e-learning condition consists of three digital learning modules (i.e., about alcohol, tobacco, and marijuana) that are sequentially offered over the course of three school years (i.e., grade 1, grade 2, and grade 3). The integral condition consists of parental participation in a parental meeting on substance use, regulation of substance use, and monitoring and counseling of students' substance use at school, over and above the three digital modules. The control condition is characterized as business as usual. Participating schools were randomly assigned to either an intervention or control condition. Participants filled out a digital questionnaire at baseline and will fill out the same questionnaire three more times at follow-up measurements (8, 20, and 32 months after baseline). Outcome variables included in the questionnaire are the percentage of binge drinking (more than five drinks per occasion), the average weekly number of drinks, and the percentage of adolescents who ever drunk a glass of alcohol and the percentage of adolescents who ever smoked a cigarette or a joint respectively for tobacco and marijuana. Discussion: This study protocol describes the design of a randomized clustered trial that evaluates the effectiveness of a school-based prevention program. We expect that significantly fewer adolescents will engage in early or excessive substance use behaviors in the intervention conditions compared to the control condition as a direct result of the intervention. We expect that the integral condition will yield most positive results, compared with the e-learning condition and control condition.10 p

A longitudinal analysis of motivation profiles at work

This paper examines the multidimensional nature of workplace motivation and the importance of a continuum structure in self-determination theory through application of complementary variable- and person-centered approaches. This approach is taken to simultaneously model the complexity of motivation and highlight interactions between motivational factors. Additionally, this study represents an initial test of the temporal stability of work motivation profiles. A sample of 510 full-time employees were recruited from a range of occupations. Results support the central importance of a general factor representing self-determination as the most influential factor in an employee’s motivation profile. However, smaller effects associated with the motivation subscales, especially identified regulation, were also noticed. Importantly, motivation profiles were found to be highly stable over the 4-month duration of this study. Results lend support to the theoretical position that while general self-determination is an essential component of motivation, it alone does not fully describe an employee’s motivation