Discrimination of prostate cancer cells and non-malignant cells using secondary ion mass spectrometry

This communication utilises Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) combined with multivariate analysis to obtain spectra from the surfaces of three closely related cell lines allowing their discrimination based upon mass spectral ions

Peak picking as a pre-processing technique for imaging time of flight secondary ion mass spectrometry

High surface sensitivity and lateral resolution imaging make time-of-flight secondary ion mass spectrometry (ToF-SIMS) a unique and powerful tool for biological analysis. However, with the leaps forward made in the capabilities of the ToF-SIMS instrumentation, the data being recorded from these instruments has dramatically increased. Unfortunately, with these large, often complex, datasets, a bottleneck appears in their processing and interpretation. Here, an application of peak picking is described and applied to ToF-SIMS images allowing for large compression of data, noise removal and improved contrast, while retaining a high percentage of the original signal. Peak picking is performed to locate peaks within ToF-SIMS data. By using this information, signal arising from the same distribution can be summed and overlapping signals separated. As a result, the data size and complexity can be dramatically reduced. This method also acts as an effective noise filter, discarding unwanted noise from the data set. Peak picking and separation are evaluated against the conventional methods of mass binning and manually selecting regions of a peak to image on a model data set

Spatiotemporal lipid profiling during early embryo development of Xenopus laevis using dynamic Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) Imaging

Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) imaging has been used for the direct analysis of single intact Xenopus laevis (X. laevis) embryo surfaces, locating multiple lipids during fertilisation and the early embryo development stages with sub-cellular lateral resolution (~4 Microns). The method avoids the complicated sample preparation for lipid analysis of the embryos, which requires selective chemical extraction of a pool of samples and chromatographic separation, while preserving the spatial distribution of biological species. The results show ToF-SIMS is capable of profiling multiple components (e.g., glycerophosphocholine, sphingomyelin, cholesterol, vitamin E, diacylglycerol, triacylglycerol) in a single X. laevis embryo. We observe lipid remodelling during fertilisation and early embryo development via time course sampling. The study also reveals the lipid distribution on the gametes fusion site. The methodology used in the study opens the possibility of studying developmental biology using high resolution imaging MS and of understanding the functional role of the biological molecules

A systematic review of strategies to recruit and retain primary care doctors

Background There is a workforce crisis in primary care. Previous research has looked at the reasons underlying recruitment and retention problems, but little research has looked at what works to improve recruitment and retention. The aim of this systematic review is to evaluate interventions and strategies used to recruit and retain primary care doctors internationally. Methods A systematic review was undertaken. MEDLINE, EMBASE, CENTRAL and grey literature were searched from inception to January 2015.Articles assessing interventions aimed at recruiting or retaining doctors in high income countries, applicable to primary care doctors were included. No restrictions on language or year of publication. The first author screened all titles and abstracts and a second author screened 20%. Data extraction was carried out by one author and checked by a second. Meta-analysis was not possible due to heterogeneity. Results 51 studies assessing 42 interventions were retrieved. Interventions were categorised into thirteen groups: financial incentives (n=11), recruiting rural students (n=6), international recruitment (n=4), rural or primary care focused undergraduate placements (n=3), rural or underserved postgraduate training (n=3), well-being or peer support initiatives (n=3), marketing (n=2), mixed interventions (n=5), support for professional development or research (n=5), retainer schemes (n=4), re-entry schemes (n=1), specialised recruiters or case managers (n=2) and delayed partnerships (n=2). Studies were of low methodological quality with no RCTs and only 15 studies with a comparison group. Weak evidence supported the use of postgraduate placements in underserved areas, undergraduate rural placements and recruiting students to medical school from rural areas. There was mixed evidence about financial incentives. A marketing campaign was associated with lower recruitment. Conclusions This is the first systematic review of interventions to improve recruitment and retention of primary care doctors. Although the evidence base for recruiting and care doctors is weak and more high quality research is needed, this review found evidence to support undergraduate and postgraduate placements in underserved areas, and selective recruitment of medical students. Other initiatives covered may have potential to improve recruitment and retention of primary care practitioners, but their effectiveness has not been established

C-60, buckminsterfullerene: its impact on biological ToF-SIMS analysis

The desire to apply the analytical abilities of the time-of-flight secondary ion mass spectrometry (ToF-SIMS) experiment to increasingly diverse samples, particularly those of a biological nature, has provided the impetus for development of new technologies to overcome some of the inherent difficulties associated with such studies. Of these, one of the most important is the widespread introduction of polyatomic ion beams to increase the secondary ion yields of the higher mass, more chemically characteristic species. The introduction of the C-60 ion beam for routine analysis has made arguably the greatest impact, providing new possibilities for analysing molecular compounds present both on the surface and in some cases in the bulk of samples such as biological tissue sections and single cells. Copyright (C) 2006 John Wiley & Sons, Ltd