Correlating the magic numbers of inorganic nanomolecular assemblies with a {Pd84} molecular-ring Rosetta Stone

Molecular self-assembly has often been suggested as the ultimate route for the bottom-up construction of building blocks atom-by-atom for functional nanotechnology, yet structural design or prediction of nanomolecular assemblies is still far from reach. Whereas nature uses complex machinery such as the ribosome, chemists use painstakingly engineered step-by-step approaches to build complex molecules but the size and complexity of such molecules, not to mention the accessible yields, can be limited. Herein we present the discovery of a palladium oxometalate {Pd₈₄}-ring cluster 3.3 nm in diameter; [Pd₈₄O₄₂(OAc)₂₈(PO₄)₄₂]^70- ({Pd₈₄} ≡ {Pd₁₂}₇) that is formed in water just by mixing two reagents at room temperature, giving crystals of the compound in just a few days. The structure of the {Pd₈₄}-ring has sevenfold symmetry, comprises 196 building blocks, and we also show, using mass spectrometry, that a large library of other related nanostructures is present in solution. Finally, by analysis of the symmetry and the building block library that construct the {Pd₈₄} we show that the correlation of the symmetry, subunit number, and overall cluster nuclearity can be used as a “Rosetta Stone” to rationalize the “magic numbers” defining a number of other systems. This is because the discovery of {Pd₈₄} allows the relationship between seemingly unrelated families of molecular inorganic nanosystems to be decoded from the overall cluster magic-number nuclearity, to the symmetry and building blocks that define such structures allowing the prediction of other members of these nanocluster families.     

Single-cell proteomic chip for profiling intracellular signaling pathways in single tumor cells

We describe a microchip designed to quantify the levels of a dozen cytoplasmic and membrane proteins from single cells. We use the platform to assess protein–protein interactions associated with the EGF-receptor-mediated PI3K signaling pathway. Single-cell sensitivity is achieved by isolating a defined number of cells (n = 0–5) in 2 nL volume chambers, each of which is patterned with two copies of a miniature antibody array. The cells are lysed on-chip, and the levels of released proteins are assayed using the antibody arrays. We investigate three isogenic cell lines representing the cancer glioblastoma multiforme, at the basal level, under EGF stimulation, and under erlotinib inhibition plus EGF stimulation. The measured protein abundances are consistent with previous work, and single-cell analysis uniquely reveals single-cell heterogeneity, and different types and strengths of protein–protein interactions. This platform helps provide a comprehensive picture of altered signal transduction networks in tumor cells and provides insight into the effect of targeted therapies on protein signaling networks.Although signal transduction inhibitors occasionally offer clinical benefit for cancer patients (1), signal flux emanating from oncogenes is often distributed through multiple pathways (2), potentially underlying the failure of most such inhibitors (3). Measuring signal flux through multiple pathways, in response to signal transduction inhibitors, may help uncover network interactions that contribute to therapeutic resistance and that are not predicted by analyzing pathways in isolation (4). The cellular and molecular complexity of a solid tumor microenvironment (5) suggests the need to study signaling in individual cancer cells.Protein–protein interactions within signaling pathways are often elucidated by assessing the levels of relevant pathway proteins in model and tumor-derived cell lines and with various genetic and molecular perturbations. Such interactions, and the implied signaling networks, may also be elucidated via quantitative measurements of multiple pathway-related proteins within single cells (6). At the single-cell level, inhibitory and activating protein–protein relationships, as well as stochastic (single-cell) fluctuations, are revealed. However, most techniques for profiling signaling pathways (7, 8) require large numbers of cells. Single-cell immunostaining (9) is promising, and some flow cytometry (6) techniques are relevant, as discussed below.We describe quantitative, multiplex assays of intracellular signaling proteins from single cancer cells using a platform called the single-cell barcode chip (SCBC). The SCBC is simple in concept: A single or defined number of cells is isolated within an approximately 2 nL volume microchamber that contains an antibody array (10) for the capture and detection of a panel of proteins. The SCBC design (11) permits lysis of each individual trapped cell.Intracellular staining flow cytometry can assay up to 11 phosphoproteins from single cells (6). Our SCBC can profile a similar size panel, but only for approximately 100 single cells per chip. Each protein is assayed twice, yielding some statistical assessment for each experiment. The SCBC is a relatively simple platform and only requires a few hundred cells per assay.We used the SCBC to study signal transduction in glioblastoma multiforme (GBM), a primary malignant brain tumor (12). GBM has been genetically characterized, yet the nature of signaling pathways downstream of key oncogenic mutations, such as epidermal growth factor receptor activating mutation (EGFRvIII) and phosphatase and tensin homolog (PTEN) tumor suppressor gene loss associated with receptor tyrosine kinase (RTK)/PI3K signaling, are incompletely understood (13–15). Single-cell experiments may also help resolve the characteristic heterogeneity of GBM.We interrogated 11 proteins directly or potentially associated with PI3K signaling (see SI Appendix, Methods I) through three isogenic GBM cell lines: U87 (expressing wild-type p53, mutant PTEN, and low levels of wild-type EGFR, no EGFRvIII) (16, 17), U87 EGFRvIII (U87 cells stably expressing EGFRvIII deletion mutant), and U87 EGFRvIII PTEN (U87 cells coexpressing EGFRvIII and PTEN) (18). Fig. 1 diagrams this biology. Each cell line was investigated under conditions of standard cell culture, in response to EGF stimulation, and after erlotinib treatment followed by EGF stimulation. The proteins assayed represented RTKs and proteins signifying activation of PI3K and MAPK signaling. They were (p- denotes phosphorylation) p-Src, p-mammalian target of rapamycin (p-mTOR), p-p70 ribosomal protein S6 kinase (p-p70S6K), p-glycogen synthase kinase-3 (p-GSK-3α/β), p-p38 mitogen activated protein kinase (p-p38α), p-extracellular regulated kinase (p-ERK), p-c-Jun N-terminal kinase (p-JNK2), p-platelet derived growth factor receptor β (p-PDGFRβ), p-vascular endothelial growth factor receptor 2 (p-VEGFR2), tumor protein 53 (P53), and total EGFR.Open in a separate windowFig. 1.The PI3K pathway activated by EGF-stimulated EGFR or by the constitutively activated EGFRvIII. All proteins in light blue with central yellow background were assayed. Orange background proteins were expressed in the cell lines U87 EGFRvIII or U87 EGFRvIII PTEN. The oval, yellow background components are the investigated molecular perturbations.     

Cognitive rehabilitation in Multiple sclerosis

Cognitive impairments are frequent in Multiple sclerosis (MS). However, most studies about efficacy of cognitive rehabilitation interventions have been criticized in terms of methods and/or design. The aim of this study is to evaluate the efficacy of cognitive rehabilitation in MS patients with a cognitive intervention (ProCogSEP* program), compared to a control intervention (discussion program). Twenty MS patients have completed this simple blind study: 10 patients followed 13 sessions (2 hours) of the ProCog-SEP¹ program. Ten other patients followed 13 sessions (2 hours) of a discussion program (Control Group). All patients underwent neuropsychological assessment, before and after their program, in order to evaluate cognitive functions. Two neuropsychologists respectively assessed the patients and conducted the group sessions. Compared to its own baseline, ProCog-SEP Group show improvements in verbal memory [free recall (p = .02), learning (p = .002)], in visual memory [free (p = .05) and delayed recall (p = .007)], in working-memory (p = .03), in verbal fluency (p = .05) and in language (p = .01). Inter group analysis show a benefit of cognitive program mainly in verbal and visual memory, and in verbal fluencies. These results support the interest of a cognitive therapeutic management of MS patients.     

Examining Perceived Stereotype Threat among Overweight/Obese Adults Using a Multi-Threat Framework

Objective

The Multi-Threat Framework accounts for potentially different forms of stereotype threat that differ in target (i.e., the individual or the group) and source (i.e., the self or others). This investigation examined how these different forms of perceived stereotype threat were related to concepts, such as group identity, stereotype endorsement, stigma consciousness, etc., among overweight and obese individuals.

Method

216 adults completed an online survey. Participants'' mean age was 23.6 (SD 10.1; range 18-64) years and mean BMI was 31.6 (SD 7.5) kg/m².

Results

Participants reported a history of feeling threatened by stereotypes related to weight. When reflecting on past experiences of perceived stereotype threat, participants reported greater levels of self/own stereotype threat compared to group stereotype threat. Level of stereotype threat was related to a number of personal characteristics (i.e., sex, BMI) and individual factors (i.e., group identity, stigma consciousness, fear of fat).

Conclusion

Individuals who are overweight report a history of being threatened by negative stereotypes. The findings support the Multi-Threat Framework for stereotype threat based on body weight. Overweight individuals'' susceptibility to stereotype threat may vary systematically depending on several factors. Future research should examine weight-related stereotypes'' impact on cognitive and behavioral outcomes.Key Words: Stereotype threat, Stigma consciousness, Obesity, Weight stigma, Group identity     

Oral health care utilization in children with disabilities

Objectives

The objectives of this report were to survey the utilization of oral health care in children and adolescents with disabilities over a 7-year period and to compare these data with the utilization pattern of their peers without disabilities. For most countries, these data have not been published in the international literature so far.

Material and methods

The cohort used was the Permanent Sample of Socially Insured Persons, an anonymous representative sample of Belgian residents. The database comprised prospective data on oral and general health care utilization and sociodemographic variables collected from 2002 up to 2008.

Results

Data were available from 326 children and adolescents with and 53,589 without disabilities. Dental attendance rates were low in both subgroups: only 50 % had a dental visit in four or more of the seven observation years. Emergency oral and medical care was recorded significantly more often in children with disabilities whereas radiographs, restorations, and orthodontic assessments and treatments more frequently in children without disabilities.

Conclusion

The present study demonstrated that dental attendance rates in both subgroups were low and that in those who attended, preventive oral health care was only infrequently attested. Further research is needed to elucidate whether the lower number of radiographs and restorations and the higher number of emergency visits observed in the subgroup with disabilities reflect unmet oral treatment needs.

Clinical relevance

Objective data on health care utilization are essential to enable governments and stakeholders to devise appropriate care and to optimize access to care for persons with disabilities.     

Single incision laparoscopic adjustable gastric band: technique,feasibility, safety and learning curve

Introduction

Single incision laparoscopic surgery (SILS) is established in many procedures but not in bariatric surgery. One explanation may be that SILS is technically demanding in morbidly obese patients. This report describes our technique and experience with single incision laparoscopic adjustable gastric banding (SILAGB).

Methods

Prospective data collection was performed on consecutive obese patients who underwent SILAGB between November 2009 and February 2011. A single 3cm transverse incision in the right upper quadrant was used for a Covidien SILS^™ multichannel access port. The technique is described with a standard pars flaccida approach and the ‘tips and tricks’ needed for a wide range of candidates using standard laparoscopic equipment.

Results

A total of 29 patients (27 female) with a median body mass index of 41kg/m² (range: 35–52kg/m²) and median age of 44 years (range: 22–57 years) underwent SILAGB. There were no ‘conversions’ to a standard laparoscopic technique. Two cases required the addition of one single 5mm port. The only complications were two postoperative wound infections (one with a port site infection requiring replacement of the port) and one faulty band requiring replacement. There were therefore two returns to theatre and no 30-day deaths. All patients were discharged on the first postoperative day. In this series, operative times reduced significantly to be comparable with the conventional laparoscopic approach.

Conclusions

SILAGB is safe and feasible in the morbidly obese. Proficiency in this technique using conventional laparoscopic equipment can be achieved with a short learning curve.     

Thoracic surgical management of colorectal lung metastases: a questionnaire survey of members of the Society for Cardiothoracic Surgery in great Britain and Ireland

Introduction

Distant metastases to liver and lung are not uncommon in colorectal cancer. Resection of metastases is accepted widely as the standard of care. However, there is no firm evidence base for this. This questionnaire survey was carried out to assess the current practice preferences of cardiothoracic surgeons in Great Britain and Ireland.

Methods

An online questionnaire survey was emailed to cardiothoracic surgeons in Great Britain and Ireland. The survey was live for 12 weeks. Responses were collated with SurveyMonkey^®.

Results

Overall, there were 75 respondents. The majority (83%) indicated thoracic surgery as a specialist interest. Almost all (99%) used thoracic computed tomography (CT) for staging; 70% added liver CT and 51% added pelvic CT. Fluorodeoxyglucose positron emission tomography was used by 86%. The most frequent indication for pulmonary resection (97%) was solitary lung metastasis without extrathoracic disease. Video assisted thoracoscopic surgery (VATS) was used by 85%. In addition, thoracotomy was used by 96%. A third (33%) used radiofrequency ablation. Synchronous liver and lung resection was contraindicated for 83% of respondents. Over three-quarters (77%) thought that scientific equipoise exists presently for lung resection for colorectal lung metastases but only 21% supported a moratorium on this type of surgery until further evidence becomes available.

Conclusions

The results confirm that the majority of respondents use conventional cross-sectional imaging and either VATS or formal thoracotomy for resection. The results emphasise the continuing need for formal randomised trials to provide evidence of any survival benefit from pulmonary metastasectomy for colorectal lung metastases.