Human resource management:strategic and international perspectives

With a strong focus on employability, this new text treats international, strategic and contemporary issues as central to the study and practice of Human Resource Management. Covering the core curriculum, this book provides all the knowledge and tools you need to get the best possible grades and achieve great career success after university. Key Features •Skills and employability focus will help you to secure a job in the tough economic climate whether as an HRM specialist or as a line manager. •Debating HRM boxes will develop your critical thinking skills, valued by examiners and employers alike. •International and cross-cultural perspectives are woven into discussion and case studies to prepare you for the realities of the global workplace. •Contemporary and strategic issues such as ethics, justice and CSR are introduced early on to underpin and enhance your understanding of the core HRM functions. •Unique final part will ensure that your skills can be applied in a range of organisational settings including SMEs and the not-for-profit and voluntary sectors. •Mapped to the CIPD’s learning outcomes but with an emphasis on the role of line managers throughout. •Companion website includes full text journal articles, glossary and chapter podcasts

Multi-frequency segmental bio-impedance device:design, development and applications

Bio-impedance analysis (BIA) provides a rapid, non-invasive technique for body composition estimation. BIA offers a convenient alternative to standard techniques such as MRI, CT scan or DEXA scan for selected types of body composition analysis. The accuracy of BIA is limited because it is an indirect method of composition analysis. It relies on linear relationships between measured impedance and morphological parameters such as height and weight to derive estimates. To overcome these underlying limitations of BIA, a multi-frequency segmental bio-impedance device was constructed through a series of iterative enhancements and improvements of existing BIA instrumentation. Key features of the design included an easy to construct current-source and compact PCB design. The final device was trialled with 22 human volunteers and measured impedance was compared against body composition estimates obtained by DEXA scan. This enabled the development of newer techniques to make BIA predictions. To add a ‘visual aspect’ to BIA, volunteers were scanned in 3D using an inexpensive scattered light gadget (Xbox Kinect controller) and 3D volumes of their limbs were compared with BIA measurements to further improve BIA predictions. A three-stage digital filtering scheme was also implemented to enable extraction of heart-rate data from recorded bio-electrical signals. Additionally modifications have been introduced to measure change in bio-impedance with motion, this could be adapted to further improve accuracy and veracity for limb composition analysis. The findings in this thesis aim to give new direction to the prediction of body composition using BIA. The design development and refinement applied to BIA in this research programme suggest new opportunities to enhance the accuracy and clinical utility of BIA for the prediction of body composition analysis. In particular, the use of bio-impedance to predict limb volumes which would provide an additional metric for body composition measurement and help distinguish between fat and muscle content.

Developing accurate models of the human airways

Objectives Particle delivery to the airways is an attractive prospect for many potential therapeutics, including vaccines. Developing strategies for inhalation of particles provides a targeted, controlled and non-invasive delivery route but, as with all novel therapeutics, in vitro and in vivo testing are needed prior to clinical use. Whilst advanced vaccine testing demands the use of animal models to address safety issues, the production of robust in vitro cellular models would take account of the ethical framework known as the 3Rs (Replacement, Reduction and Refinement of animal use), by permitting initial screening of potential candidates prior to animal use. There is thus a need for relevant, realistic in vitro models of the human airways. Key findings Our laboratory has designed and characterised a multi-cellular model of human airways that takes account of the conditions in the airways and recapitulates many salient features, including the epithelial barrier and mucus secretion. Summary Our human pulmonary models recreate many of the obstacles to successful pulmonary delivery of particles and therefore represent a valid test platform for screening compounds and delivery systems.

The use of erythrocytic and animal models in the study of protein phosphorylation

Phosphorylation processes are common post-transductional mechanisms, by which it is possible to modulate a number of metabolic pathways. Proteins are highly sensitive to phosphorylation, which governs many protein-protein interactions. The enzymatic activity of some protein tyrosine-kinases is under tyrosine-phosphorylation control, as well as several transmembrane anion-fluxes and cation exchanges. In addition, phosphorylation reactions are involved in intra and extra-cellular 'cross-talk' processes. Early studies adopted laboratory animals to study these little known phosphorylation processes. The main difficulty encountered with these animal techniques was obtaining sufficient kinase or phosphatase activity suitable for studying the enzymatic process. Large amounts of biological material from organs, such as the liver and spleen were necessary to conduct such work with protein kinases. Subsequent studies revealed the ubiquity and complexity of phosphorylation processes and techniques evolved from early rat studies to the adaptation of more rewarding in vitro models. These involved human erythrocytes, which are a convenient source both for the enzymes, we investigated and for their substrates. This preliminary work facilitated the development of more advanced phosphorylative models that are based on cell lines. © 2005 Elsevier B.V. All rights reserved.

Expansion, harvest and cryopreservation of human mesenchymal stem cells in a serum-free microcarrier process

Human mesenchymal stem cell (hMSC) therapies are currently progressing through clinical development, driving the need for consistent, and cost effective manufacturing processes to meet the lot-sizes required for commercial production. The use of animal-derived serum is common in hMSC culture but has many drawbacks such as limited supply, lot-to-lot variability, increased regulatory burden, possibility of pathogen transmission, and reduced scope for process optimization. These constraints may impact the development of a consistent large-scale process and therefore must be addressed. The aim of this work was therefore to run a pilot study in the systematic development of serum-free hMSC manufacturing process. Human bone-marrow derived hMSCs were expanded on fibronectin-coated, non-porous plastic microcarriers in 100mL stirred spinner flasks at a density of 3×10⁵cells.mL^-1 in serum-free medium. The hMSCs were successfully harvested by our recently-developed technique using animal-free enzymatic cell detachment accompanied by agitation followed by filtration to separate the hMSCs from microcarriers, with a post-harvest viability of 99.63±0.03%. The hMSCs were found to be in accordance with the ISCT characterization criteria and maintained hMSC outgrowth and colony-forming potential. The hMSCs were held in suspension post-harvest to simulate a typical pooling time for a scaled expansion process and cryopreserved in a serum-free vehicle solution using a controlled-rate freezing process. Post-thaw viability was 75.8±1.4% with a similar 3h attachment efficiency also observed, indicating successful hMSC recovery, and attachment. This approach therefore demonstrates that once an hMSC line and appropriate medium have been selected for production, multiple unit operations can be integrated to generate an animal component-free hMSC production process from expansion through to cryopreservation.

Amyloid β 1-42 induces hypometabolism in human stem cell-derived neuron and astrocyte networks

Alzheimer's disease (AD) is the most common form of dementia, affecting more than 35 million people worldwide. Brain hypometabolism is a major feature of AD, appearing decades before cognitive decline and pathologic lesions. To date, the majority of studies on hypometabolism in AD have used transgenic animal models or imaging studies of the human brain. As it is almost impossible to validate these findings using human tissue, alternative models are required. In this study, we show that human stem cell-derived neuron and astrocyte cultures treated with oligomers of amyloid beta 1-42 (Aβ1-42) also display a clear hypometabolism, particularly with regard to utilization of substrates such as glucose, pyruvate, lactate, and glutamate. In addition, a significant increase in the glycogen content of cells was also observed. These changes were accompanied by changes in NAD+ /NADH, ATP, and glutathione levels, suggesting a disruption in the energy-redox axis within these cultures. The high energy demands associated with neuronal functions such as memory formation and protection from oxidative stress put these cells at particular risk from Aβ-induced hypometabolism. Further research using this model may elucidate the mechanisms associated with Aβ-induced hypometabolism.

Brain-derived neurotrophic factor as an indicator of chemical neurotoxicity:an animal-free CNS cell culture model

Recent changes to the legislation on chemicals and cosmetics testing call for a change in the paradigm regarding the current 'whole animal' approach for identifying chemical hazards, including the assessment of potential neurotoxins. Accordingly, since 2004, we have worked on the development of the integrated co-culture of post-mitotic, human-derived neurons and astrocytes (NT2.N/A), for use as an in vitro functional central nervous system (CNS) model. We have used it successfully to investigate indicators of neurotoxicity. For this purpose, we used NT2.N/A cells to examine the effects of acute exposure to a range of test chemicals on the cellular release of brain-derived neurotrophic factor (BDNF). It was demonstrated that the release of this protective neurotrophin into the culture medium (above that of control levels) occurred consistently in response to sub-cytotoxic levels of known neurotoxic, but not non-neurotoxic, chemicals. These increases in BDNF release were quantifiable, statistically significant, and occurred at concentrations below those at which cell death was measureable, which potentially indicates specific neurotoxicity, as opposed to general cytotoxicity. The fact that the BDNF immunoassay is non-invasive, and that NT2.N/A cells retain their functionality for a period of months, may make this system useful for repeated-dose toxicity testing, which is of particular relevance to cosmetics testing without the use of laboratory animals. In addition, the production of NT2.N/A cells without the use of animal products, such as fetal bovine serum, is being explored, to produce a fully-humanised cellular model.

Using an in vitro human airway model to study the toxic effects of components of e-cigarettes

Cigarette smoke is a complex mixture of more than 4000 hazardous chemicals including the carcinogenic benzopyrenes. Nicotine, the most potent component of tobacco, is responsible for the addictive nature of cigarettes and is a major component of e-cigarette cartridges. Our study aims to investigate the toxicity of nicotine with special emphasis on the replacement of animals. Furthermore, we intend to study the effect of nicotine, cigarette smoke and e-cigarette vapours on human airways. In our current work, the BEAS 2B human bronchial epithelial cell line was used to analyse the effect of nicotine in isolation, on cell viability. Concentrations of nicotine from 1.1µM to 75µM were added to 5x105 cells per well in a 96 well plate and incubated for 24 hours. Cell titre blue results showed that all the nicotine treated cells were more metabolically active than the control wells (cells alone). These data indicate that, under these conditions, nicotine does not affect cell viability and in fact, suggests that there is a stimulatory effect of nicotine on metabolism. We are now furthering this finding by investigating the pro-inflammatory response of these cells to nicotine by measuring cytokine secretion via ELISA. Further work includes analysing nicotine exposure at different time points and on other epithelial cells lines like Calu-3.

Nicotine exposure reduces cell viability but induces anti-inflammatory effects in human cystic fibrosis bronchial epithelial cells

Background: Mouse models of cystic fibrosis (CF) fail to truly represent the respiratory pathology. We have consequently developed human airways cell culture models to address this. The impact of cigarette smoke within the CF population is well documented, with exposure being known to worsen lung function. As nicotine is often perceived to be a less harmful component of tobacco smoke, this research aimed to identify its effects upon viability and inflammatory responses of CF (IB3-1) and CF phenotype corrected (C38) bronchial epithelial cells. Methods: IB3-1 and C38 cell lines were exposed to increasing concentrations of nicotine (0.55-75μM) for 24 hours. Cell viability was assessed via Cell Titre Blue and the inflammatory response with IL-6 and IL-8 ELISA. Results: CF cells were more sensitive; nicotine significantly (P<0.05) reduced cell viability at all concentrations tested, but failed to have a marked effect on C38 viability. Whilst nicotine induced anti-inflammatory effects in CF cells with a significant reduction in IL-6 and IL-8 release, it had no effect on chemokine release by C38 cells. Conclusion: CF cells may be more vulnerable to inhaled toxicants than non-CF cells. As mice lack a number of human nicotinic receptor subunits and fail to mimic the characteristic pathology of CF, these data emphasise the importance of employing relevant human cell lines to study a human-specific disease.