Unravelling the mechanisms that determine the uptake and metabolism of magnetic single and multicore nanoparticles in a Xenopus laevis model.

Multicore superparamagnetic nanoparticles have been proposed as ideal tools for some biomedical applications because of their high magnetic moment per particle, high specific surface area and long term colloidal stability. Through controlled aggregation and packing of magnetic cores it is possible to obtain not only single-core but also multicore and hollow spheres with internal voids. In this work, we compare toxicological properties of single and multicore nanoparticles. Both types of particles showed moderate in vitro toxicity (MTT assay) tested in Hep G2 (human hepatocellular carcinoma) and Caco-2 (human colorectal adenocarcinoma) cells. The influence of surface chemistry in their biological behavior was also studied after functionalization with O,O'-bis(2-aminoethyl) PEG (2000 Da). For the first time, these nanoparticles were evaluated in a Xenopus laevis model studying their whole organism toxicity and their impact upon iron metabolism. The degree of activation of the metabolic pathway depends on the size and surface charge of the nanoparticles which determine their uptake. The results also highlight the potential of Xenopus laevis model bridging the gap between in vitro cell-based assays and rodent models for toxicity assessment to develop effective nanoparticles for biomedical applications.

Diurnal variation in the salivary melatonin responses to exercise: relation to exercise-mediated tachycardia.

Salivary melatonin concentration is an established marker of human circadian rhythmicity. It is thought that melatonin is relatively robust to the masking effects of exercise. Nevertheless, the extent and even the direction of exercise-related change is unclear, possibly due to between-study differences in the time of day exercise is completed. Therefore, we aimed to compare melatonin responses between morning and afternoon exercise, and explore the relationships between exercise-related changes in melatonin and heart rate. At 08:00 and 17:00 hours, seven male subjects (mean ± SD age, 27 ± 5 years) completed 30 min of cycling at 70% peak oxygen uptake followed by 30 min of rest. Light intensity was maintained at ~150 lx. Salivary melatonin (ELISA) and heart rate were measured at baseline, 15 min during exercise, immediately post-exercise and following 30 min recovery. Melatonin was ≈15 pg ml(-1) higher in the morning trials compared with the afternoon (P = 0.030). The exercise-related increase in melatonin was more pronounced (P = 0.024) in the morning (11.1 ± 8.7 pg ml(-1)) than in the afternoon (5.1 ± 5.7 pg ml(-1)). The slope of the heart rate-melatonin relationship was significantly (P = 0.020) steeper in the morning (0.12 pg ml(-1) beats(-1 )min(-1)) than in the afternoon (0.03 pg ml(-1) beats(-1 )min(-1)). In conclusion, we report for the first time that the masking effect of moderate-intensity exercise on melatonin is approximately twice as high in the morning than the afternoon. The much steeper relationship between heart rate and melatonin changes in the morning raises the possibility that time of day alters the relationships between exercise-mediated sympathetic nervous activity and melatonin secretion.

Acquired factor V inhibitor in a critically ill patient.

Acquired inhibitor of factor V is a rare condition with a variety of clinical manifestations, from extremely mild to life threatening haemorrhage. We present a case from our intensive care unit as a reminder of the less common causes of elevated prothombin and activated partial thromboplastin times, and how knowledge of the variable presentation may aid management.

Structural and functional connectivity of marine fishes within a semi-enclosed Newfoundland fjord.

The interplay between structural connectivity (i.e. habitat continuity) and functional connectivity (i.e. dispersal probability) in marine fishes was examined in a coastal fjord (Holyrood Pond, Newfoundland, Canada) that is completely isolated from the North Atlantic Ocean for most of the year. Genetic differentiation was described in three species (rainbow smelt Osmerus mordax, white hake Urophycis tenuis and Atlantic cod Gadus morhua) with contrasting life histories using seven to 10 microsatellite loci and a protein-coding locus, PanI (G. morhua). Analysis of microsatellite differentiation indicated clear genetic differences between the fjord and coastal regions; however, the magnitude of difference was no more elevated than adjacent bays and was not enhanced by the fjord's isolation. Osmerus mordax was characterized by the highest structure overall with moderate differentiation between the fjord and St Mary's Bay (F(ST)c.0.047). In contrast, U. tenuis and G. morhua displayed weak differentiation (F(ST) < 0.01). Nonetheless, these populations did demonstrate high rates (< 75%) of Bayesian self-assignment. Furthermore, elevated differentiation was observed at the PanI locus in G. morhua between the fjord and other coastal locations. Interestingly, locus-specific genetic differentiation and expected heterozygosity were negatively associated in O. mordax, in contrast to the positive associations observed in U. tenuis and G. morhua. Gene flow in these species is apparently unencumbered by limited structural connectivity, yet the observed differentiation suggests that population structuring exists over small scales despite high dispersal potential.

Systematics of radon at the Wairakei geothermal region, New Zealand.

222Rn and 220Rn in geothermal steam at Wairakei, NZ, range from 11 to 19, 500 Bq kg-1, and 25 to 16, 700 Bq kg-1, respectively, but do not cause toxic concentrations in air. The wide ranges are mainly due to differences in different physical conditions underground (e.g. thin silica diffusion barriers), not geochemical differences. Groundwater Rn from outside the area probably plays only a minor role. 210Po was found present in non-toxic levels in the steam. Historical records showed little change in Rn concentration over several decades, therefore potentially hazardous concentrations might be predicted from early exploration. 220Rn concentrations at Wairakei should decrease as the field becomes steam-dominated. Rock surfaces were variably leached or enriched with U, Th, Ra and 210Pb, providing a possible model for deposition in cooler regions near the field. Estimates of 222Rn permeability ranged from 2 to 77% of the maximum possible, with a median of 13%.

Applying preventable drug-related morbidity indicators to the electronic patient record in UK primary care: methodological development.

BACKGROUND AND OBJECTIVE: Measuring and assessing the quality of health care services is an issue of high international importance. Providing data can be reliably extracted, making use of the electronic patient record (EPR) could help practitioners fulfil clinical governance obligations and ultimately improve the quality of patient care. The objective of this paper is to describe (i) the process used to apply a series of clinical indicators for preventable drug-related morbidity (PDRM) in the EPR, (ii) problems encountered and (iii) our attempts to resolve them. METHOD: The PDRM indicators were applied retrospectively in the EPR of all patients aged 18 years and over in nine general practices using the Morbidity Information and Query Export Syntax (MIQUEST) computer software programme. RESULTS: Issues identified as requiring attention when attempting to extract data from the EPR include considering the ranges to be used for age and biochemical test results, accuracy of diagnosis and drug coding, the level of complexity of the information needed, and how best to manipulate the resulting data. Practical difficulties encountered were ensuring the query coding schemes were sufficiently robust and comprehensive to secure reliable data extraction, the number of MIQUEST queries required to express each indicator, the time-consuming nature of the stages involved in the data manipulation process. DISCUSSION: Despite some practical difficulties, we have successfully used MIQUEST to identify potential preventable drug-related morbidities from the EPR. The quality of information that can be extracted from the EPR is obviously limited by the accuracy and completeness of the data on the system and the ability of the enquirer to reliably extract and manipulate that data. CONCLUSION: Although some of the problems encountered were specific to the MIQUEST software, many, including considering appropriate ranges for age and biochemical test results and paying careful attention to the reliability of drug and diagnosis coding, are relevant whenever data are extracted from the EPR for any purpose.

Preventing drug related morbidity: a process for facilitating changes in practice.

AIM: To describe how quantitative data obtained from applying a series of indicators for preventable drug related morbidity (PDRM) in the electronic patient record in English general practice can be used to facilitate changes aimed at helping to improve medicines management. DESIGN: A multidisciplinary discussion forum held at each practice facilitated by a clinical researcher. SUBJECTS AND SETTING: Eight English general practices. OUTCOME MEASURES: Issues discussed at the multidisciplinary discussion forum and ideas generated by practices for tackling these issues. Progress made by practices after 1, 3, and 6 months. RESULTS: A number of clinical issues were raised by the practices and ideas for moving them forward were discussed. The issues that were easiest and most straightforward to deal with (for example, reviewing specific patient groups) were quickly addressed in most instances. Practices were less likely to have taken steps towards addressing issues at a systems level. CONCLUSIONS: Data generated from applying PDRM indicators can be used to facilitate practice-wide discussion on medicines management. Different practices place different priority levels on the issues they wish to pursue. Individual practice "ownership" of these, together with having a central committed figure at the practice, is key to the success of the process.

Patient safety features of clinical computer systems: questionnaire survey of GP views.

AIM: To investigate general practitioners' (GPs') stated knowledge, use and training needs related to the patient safety features of computerised clinical systems in England. DESIGN: Questionnaire survey. SUBJECTS AND SETTING: GPs from six English primary care trusts. OUTCOME MEASURES: GPs' views on the importance of specified patient safety features on their computer system; their knowledge of the presence of specified safety features; previous training and perceived future training needs. RESULTS: Three hundred and eighty one GPs (64.0%) completed and returned the questionnaire. Although patient safety features were considered to be an important part of their computer system by the vast majority of GPs, many were unsure as to whether the system they were currently using possessed some of the specified features. Some respondents erroneously believed that their computers would warn them about potential contraindications or if an abnormal dose frequency had been prescribed. Only a minority had received formal training on the use of their system's patient safety features. CONCLUSIONS: Patient safety was an issue high on the agenda of this GP sample. The importance of raising GPs' awareness of both the potential use and deficiencies of the patient safety features on their systems and ensuring that appropriate training is available should not be underestimated.

Indicators for preventable drug related morbidity: application in primary care.

AIM: To apply in practice a series of validated indicators for preventable drug related morbidity (PDRM). DESIGN: A pilot study to identify retrospectively potential PDRM events over a 2 year 3 month time frame using the MIQUEST computer software program. SUBJECTS AND SETTING: The electronic patient record of all patients aged 18 years and over in nine English general practices. OUTCOME MEASURES: The number of potential PDRM events identified, as defined by the indicators. RESULTS: Five hundred and seven potential PDRM events were identified from 49 658 electronic patient records, giving an overall incidence of 1.0%. A small number of the indicators (n = 4) accounted for approximately 60% of the events, while for many indicators few events were identified. The most common events related to the use of non-steroidal anti-inflammatory drugs in patients with congestive heart failure or hypertension, lack of monitoring in patients prescribed angiotensin converting enzyme inhibitors, and the use of hypnotic-anxiolytic agents. CONCLUSIONS: A small number of indicators contributed to the majority of the PDRM events. Interrogation of electronic patient records in primary care using computerised queries shows potential for detecting PDRM.

The transcription factors hypoxia-inducible factor 1alpha and Ets-1 colocalize in the hypoxic synovium of inflamed joints in adjuvant-induced arthritis.

OBJECTIVE: To determine the relationship between hypoxia and the expression of Ets-1 and hypoxia-inducible factor 1alpha (HIF-1alpha) in both normal and inflamed joints. Adjuvant-induced arthritis (AIA) was used as the model system, since it mirrors many aspects of the pathology of rheumatoid arthritis. METHODS: Adjuvant arthritis was induced in a group of 10 female Lewis rats. A second group of 10 uninjected female Lewis rats served as naive controls. When a maximum clinical joint score was achieved in the AIA group, all 20 rats were injected with the specific hypoxic cell marker Hypoxyprobe-1 and subsequently killed. Hypoxyprobe-1 adducts, Ets-1, and HIF-1alpha were localized in the joints of the hind feet from these groups using immunohistochemistry. RESULTS: Compared with the joints from control rats, inflamed joints contained markedly more cells with Hypoxyprobe-1 adduct immunoreactivity, Ets-1-immunoreactive nuclei, and nuclear immunoreactivity for both Ets-1 and HIF-1alpha. CONCLUSION: Our results demonstrate the presence of hypoxia in inflamed joints in this experimental model of arthritis. The colocalization of Ets-1 and HIF-1alpha in these hypoxic areas suggests that hypoxia may induce Ets-1 and HIF-1alpha expression during joint inflammation.

Preventing drug-related morbidity--the development of quality indicators.

OBJECTIVE: To describe the process that has been undertaken to (i) validate further UK indicators for preventable drug-related morbidity (PDRM) generated by a previous study and (ii) develop additional new indicators derived from UK clinical practice. DESIGN: A two-round Delphi questionnaire survey. SETTING: A UK study based in primary care. PARTICIPANTS: A purposively selected sample of primary care pharmacists (n = 9) and general practitioners (n = 8). OUTCOME MEASURES: The establishment of consensus among the panel as to whether an indicator represented a PDRM. RESULTS: The pre-defined level of consensus was achieved for 24 indicators (59%; 24 of 41). CONCLUSIONS: We have identified that although mechanisms exist for identifying 'the outcome' component of PDRM indicators, identifying the 'pattern of care' that is needed to prevent their occurrence is far more challenging. Nonetheless, we have taken considerable steps along the path of validating such indicators. Future operationalization in a general practice setting should help to facilitate improvements in medicine management in primary care and ultimately benefit patients.

Preventing drug-related morbidity--determining valid indicators.

OBJECTIVE: To describe the process that is being undertaken to validate a series of indicators for preventable drug-related morbidity - originally developed in the US - for application in the UK health care system. DESIGN: A two-round Delphi questionnaire survey after a preliminary validation of the indicators within the University of Manchester School of Pharmacy. SETTING: A primary care study set in the UK. STUDY PARTICIPANTS: A purposively selected sample of general practitioners with a specific responsibility for prescribing-related issues (n = 6) and pharmacists actively involved in medication review in primary care (n = 10). MAIN OUTCOME MEASURES: The establishment of consensus among the participants that an indicator reflected preventable drug-related morbidity in primary care. RESULTS: After preliminary validation, 37 of the original 57 US indicators were retained. The Delphi panel generated 16 additional new indicators in the first round. At the end of the second round, the pre-defined level of consensus was reached for 29 indicators (19 of the US generated indicators; 10 generated by the panel in the first round). CONCLUSIONS: The Delphi results highlighted differences in both the clinical perspective and, possibly, philosophical viewpoints of health professionals practising in the UK and US health care systems. Further work, located in both primary and secondary care, is now in progress to operationalize the indicators. This process will form a key part of the refining, and hence further validation, of the indicators. The future development of prospective medical-record-based indicators should facilitate a reduction in the human, clinical, and economic burden of drug-related morbidity.

Initial study of using a laminar fluid diffusion interface for sample preparation in high-performance liquid chromatography.

This report describes a new microfluidic device called the H Filter for sample preparation prior to HPLC. The H Filters make possible a diffusional transfer of an analyte from a sample stream into a stream of a "receiver" fluid. Existing mathematical models can be used for optimizing experimental conditions. The authors have selected the extraction of the antibiotic cephradine from blood to demonstrate the utility of the new device. The extracts of blood samples spiked with cephradine levels between 0.2 and 100 microg/ml were analyzed using a C8 reversed-phase column and UV detection at 260 nm. The HPLC results were in good agreement with theory. The recovery of 32.2+/-2.8% was uniform over the entire range of cephradine concentrations. The new method completely avoids the use of centrifuges, that is otherwise typical for most current methodologies for the preparation of blood samples prior to HPLC analysis.

GPs' attitudes to minor ailments.

BACKGROUND: It is generally considered that a significant proportion of 'inappropriate' demand for GP services is generated by consultations for minor ailments. How GPs manage minor ailments is likely to affect how patients perceive and handle similar illnesses in the future. Whilst this potentially has significant implications for general practice workload, research investigating GP' attitudes towards minor ailments and their management is sparse. OBJECTIVE: Our aim was to describe GP' experiences and perceptions of minor ailment consultations and their attitudes towards minor ailment management. METHODS: A questionnaire survey was conducted in 1999, derived from a series of 20 qualitative interviews with practising GPs. The survey was sent to one GP randomly selected from each practice (n = 759) in eight English health authorities. Attitudinal statements were analysed using factor analysis. RESULTS: Four hundred and fourteen GPs (54.5%) completed and returned the questionnaire. Respondents were consulted regularly about minor illness or symptoms, with almost all (95.6%) having experienced a minor ailment consultation in the previous week. Factor analysis suggested four issues to be of importance in determining GP' attitudes to minor ailment management. These were attitudes towards pharmacists, attitudes towards patient empowerment, frustration with minor ailment consultations and attitudes towards caution/risk. CONCLUSION: Although GPs are clearly frustrated by the level of minor ailment consultations, this study suggests that there may be complex factors which influence their attitudes. For the optimal management of minor ailments, inter-professional relationships potentially are of great importance. With increasing patient demand, it is essential that finite health care resources are accessible, appropriate and used in an optimal way.

Lab-on-a-chip sample preparation using laminar fluid diffusion interfaces--computational fluid dynamics model results and fluidic verification experiments.

Microfluidic structures for the generation of laminar fluid diffusion interfaces (LFDIs) for sample preparation and analysis are discussed. Experimental data and the results of fluid modeling are shown. LFDIs are generated when two or more streams flow in parallel in a single microfluidic structure without any mixing of the fluids other than by diffusion of particles across the diffusion interface. It has been shown that such structures can be used for diffusion-based separation and detection applications. The method has been applied to DNA desalting, the extraction of small proteins from whole blood samples, and the detection of various constituents in whole blood, among other examples. In this paper the design and manufacture of self-contained microfluidic cartridges for the extraction of small molecules from a mixture of small and large molecules by diffusion is demonstrated. The cards are operated without any external instrumentation, and use hydrostatic pressure as the driving force. The performance of the cartridges is illustrated by separating fluorescein from a mixture of fluorescein and dextran of molecular weight 2 x 10(6). In a single pass, 98.6% of dextran was retained in the product whereas 43.1% of fluorescein was removed. The method is adjustable for different separation requirements, and computational fluid dynamics (CFD) models are shown that demonstrate the tuning of various microfluidic parameters to optimize separation performance. Other applications of LFDIs for establishment of stable concentration gradients, and the exposure of chemical constituents or biological particles to these concentration gradients are shown qualitatively. Microfluidic chips have been designed for high-throughput screening applications that enable the uniform and controlled exposure of cells to lysing agents, thus enabling the differentiation of cells by their sensitivity to specific agents in an on-chip cytometer coupled directly to the lysing structure.

GP survey response rate: a miscellany of influencing factors.

BACKGROUND: GP response to surveys is acknowledged to vary widely. The minimization of non-response bias and the generalizability of findings are fundamental research issues. OBJECTIVE: The aim of this study was to identify the factors that had influenced GPs' decisions to complete a questionnaire. METHODS: A short questionnaire eliciting GPs' views on minor ailment consultations was sent to 759 GPs from eight English health authorities. The response rate was 54.5%. Factors perceived by respondents to have influenced their decision to complete this questionnaire were also assessed. Subsequently, a feedback summary, together with a short evaluation form, was sent to those GPs requesting it. RESULTS: The response from GPs located in the London area was significantly lower than that from those elsewhere. Respondents identified questionnaire length and the originating institution as the two major factors influencing their decision to return the survey. A single mailing of the evaluation form yielded a response rate of >60% predominantly positive comments. CONCLUSION: Many factors influence a GP's decision to complete a survey. The effect of location has, to date, largely been ignored. Furthermore, this study suggested feedback to be an important issue. Within health services research, all possible factors need to be considered to maximize response, reduce non-response bias and ultimately facilitate the dissemination of findings.

Evidence for oxidised low density lipoprotein in synovial fluid from rheumatoid arthritis patients.

The oxidative modification of human LDL has been implicated in atherosclerosis, but the mechanisms by which such modification occurs in vivo are not fully understood. In the present study, we have isolated LDL from knee-joint synovial fluid of patients with rheumatoid arthritis. We demonstrate that such LDL is oxidatively modified as evidenced by an increased negative charge, distorted particulate nature and more rapid degradation by cultured macrophages. These results indicate that formation of oxidised LDL is associated with the local inflammatory response. Because the cellular interactions in rheumatoid arthritis have analogies with those in atherogenesis, we suggest that the rheumatoid joint is a useful model of atherosclerosis in which the in vivo process of LDL oxidation may be readily studied.