Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices

Synthesis of monodisperse iron-platinum (FePt) nanoparticles by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine stabilizers is reported. The FePt particle composition is readily controlled, and the size is tunable from 3- to 10-nanometer diameter with a standard deviation of less than 5%. These nanoparticles self-assemble into three-dimensional superlattices. Thermal annealing converts the internal particle structure from a chemically disordered face-centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies. These assemblies are chemically and mechanically robust and can support high-density magnetization reversal transitions.

Morpholino antisense oligomers: design, preparation, and properties

Antisense promised major advances in treating a broad range of intractable diseases, but in recent years progress has been stymied by technical problems, most notably inadequate specificity, ineffective delivery into the proper subcellular compartment, and unpredictable activity within cells. Herein is an overview of the design, preparation, and properties of Morpholino oligos, a novel antisense structural type that solves the sequence specificity problem and provides high and predictable activity in cells. Morpholino oligos also exhibit little or no nonantisense activity, afford good water solubility, are immune to nucleases, and are designed to have low production costs.

The Aarhus statement: improving design and reporting of studies on early cancer diagnosis

Early diagnosis is a key factor in improving the outcomes of cancer patients. A greater understanding of the pre-diagnostic patient pathways is vital yet, at present, research in this field lacks consistent definitions and methods. As a consequence much early diagnosis research is difficult to interpret. A consensus group was formed with the aim of producing guidance and a checklist for early cancer-diagnosis researchers. A consensus conference approach combined with nominal group techniques was used. The work was supported by a systematic review of early diagnosis literature, focussing on existing instruments used to measure time points and intervals in early cancer-diagnosis research. A series of recommendations for definitions and methodological approaches is presented. This is complemented by a checklist that early diagnosis researchers can use when designing and conducting studies in this field. The Aarhus checklist is a resource for early cancer-diagnosis research that should promote greater precision and transparency in both definitions and methods. Further work will examine whether the checklist can be readily adopted by researchers, and feedback on the guidance will be used in future updates.

A systematic review of the effects of screening for colorectal cancer using the faecal occult blood test, hemoccult

OBJECTIVE

To review effectiveness of screening for colorectal cancer with faecal occult blood test, Hemoccult, and to consider benefits and harms of screening.

DESIGN

Systematic review of trials of Hemoccult screening, with meta-analysis of results from the randomised controlled trials.

SUBJECTS

Four randomised controlled trials and two non-randomised trials of about 330 000 and 113 000 people respectively aged >=40 years in five countries.

MAIN OUTCOME MEASURES

Meta-analysis of effects of screening on mortality from colorectal cancer.

RESULTS

Quality of trial design was generally high, and screening resulted in a favourable shift in the stage distribution of colorectal cancers in the screening groups. Meta-analysis of mortality results from the four randomised controlled trials showed that those allocated to screening had a reduction in mortality from colorectal cancer of 16% (relative risk 0.84 (95% confidence interval 0.77 to 0.93)). When adjusted for attendance for screening, this reduction was 23% (relative risk 0.77 (0.57 to 0.89)) for people actually screened. If a biennial Hemoccult screening programme were offered to 10 000 people and about two thirds attended for at least one Hemoccult test, 8.5 (3.6 to 13.5) deaths from colorectal cancer would be prevented over a period of 10 years.

CONCLUSION

Although benefits of screening are likely to outweigh harms for populations at high risk of colorectal cancer, more information is needed about the harmful effects of screening, the community's responses to screening, and costs of screening for different healthcare systems before widespread screening can be recommended.

Minimum field strength in precessional magnetization reversal

Ultrafast magnetic field pulses as short as 2 picoseconds are able to reverse the magnetization in thin, in-plane, magnetized cobalt films. The field pulses are applied in the plane of the film, and their direction encompasses all angles with the magnetization. At a right angle to the magnetization, maximum torque is exerted on the spins. In this geometry, a precessional magnetization reversal can be triggered by fields as small as 184 kiloamperes per meter. Applications in future ultrafast magnetic recording schemes can be foreseen.

UK Lung Cancer RCT Pilot Screening Trial: baseline findings from the screening arm provide evidence for the potential implementation of lung cancer screening

Background

Lung cancer screening using low-dose CT (LDCT) was shown to reduce lung cancer mortality by 20% in the National Lung Screening Trial.

Methods

The pilot UK Lung Cancer Screening (UKLS) is a randomised controlled trial of LDCT screening for lung cancer versus usual care. A population-based questionnaire was used to identify high-risk individuals. CT screen-detected nodules were managed by a pre-specified protocol. Cost effectiveness was modelled with reference to the National Lung Cancer Screening Trial mortality reduction.

Results

247 354 individuals aged 50–75 years were approached; 30.7% expressed an interest, 8729 (11.5%) were eligible and 4055 were randomised, 2028 into the CT arm (1994 underwent a CT). Forty-two participants (2.1%) had confirmed lung cancer, 34 (1.7%) at baseline and 8 (0.4%) at the 12-month scan. 28/42 (66.7%) had stage I disease, 36/42 (85.7%) had stage I or II disease. 35/42 (83.3%) had surgical resection. 536 subjects had nodules greater than 50 mm³ or 5 mm diameter and 41/536 were found to have lung cancer. One further cancer was detected by follow-up of nodules between 15 and 50 mm³ at 12 months. The baseline estimate for the incremental cost-effectiveness ratio of once-only CT screening, under the UKLS protocol, was £8466 per quality adjusted life year gained (CI £5542 to £12 569).

Conclusions

The UKLS pilot trial demonstrated that it is possible to detect lung cancer at an early stage and deliver potentially curative treatment in over 80% of cases. Health economic analysis suggests that the intervention would be cost effective—this needs to be confirmed using data on observed lung cancer mortality reduction.

Trial registration

ISRCTN 78513845.

A systematic review of the effectiveness of promoting lifestyle change in general practice

BACKGROUND

There is increasing evidence that particular lifestyle behaviours increase the risk of disease and it is widely argued that GPs are ideally placed to encourage patients to modify their behaviour in these areas and thereby reduce their disease risk. There is therefore a need for evidence that GP-based lifestyle interventions are effective in eliciting behaviour change. As there has been no comprehensive attempt to review the literature on this subject, we chose to conduct a systematic review, incorporating meta-analytic techniques where possible, to address this need.

OBJECTIVES

This study aimed to examine how effective lifestyle advice provided by GPs is in changing patient behaviour. The following four areas of behaviour were examined: smoking, alcohol consumption, diet, and exercise.

METHOD

The review was restricted to English-language reports of trials which investigated the effectiveness of lifestyle advice provided in a general practice setting. Studies were included where it could be established that subjects were randomly allocated to experimental groups and where a comparison was made between either a "no intervention' or "usual care' control group, or between advice of differing intensities. Six electronic databases were searched and a total of 37 trials were selected for inclusion in the review. Meta-analytic techniques were employed to analyse the data from the smoking advice trials. The results form the trials concerned with the other three behaviours did not lend themselves to this form of analysis. Outcome data were extracted from these trials and summarized in tabular form.

RESULTS

The results of this review suggest that whilst many of the general practice-based lifestyle interventions show promise in effecting small changes in behaviour, none appears to produce substantial changes.

CONCLUSION

There is a need for more extensive and rigorous research in this area before substantial public funds are committed to general practice-based health promotion. Furthermore, it is clear that if general practice-based interventions are to be effective in a public health sense, a greater number of GPs will need to become involved in promoting behaviour change than the literature suggests is currently occurring.

Antidepressant drugs and generic counselling for treatment of major depression in primary care: randomised trial with patient preference arms

OBJECTIVES

To compare the efficacy of antidepressant drugs and generic counselling for treating mild to moderate depression in general practice. To determine whether the outcomes were similar for patients with randomly allocated treatment and those expressing a treatment preference.

DESIGN

Randomised controlled trial, with patient preference arms. Follow up at 8 weeks and 12 months and abstraction of GP case notes.

SETTING

31 general practices in Trent region.

PARTICIPANTS

Patients aged 18-70 who met research diagnostic criteria for major depression; 103 patients were randomised and 220 patients were recruited to the preference arms.

MAIN OUTCOME MEASURES

Difference in mean Beck depression inventory score; time to remission; global outcome assessed by a psychiatrist using all data sources; and research diagnostic criteria.

RESULTS

At 12 months there was no difference between the mean Beck scores in the randomised arms. Combining the randomised and patient preference groups, the difference in Beck scores was 0.4 (95% confidence interval -2.7 to 3.5). Patients choosing counselling did better than those randomised to it (mean difference in Beck score 4.6, 0.0 to 9.2). There was no difference in the psychiatrist's overall assessment of outcome between any of the groups. 221/265 (83%) of participants with a known outcome had a remission. Median time to remission was shorter in the group randomised to antidepressants than the other three groups (2 months v 3 months). 33/221 (15%) patients had a relapse.

CONCLUSIONS

Generic counselling seems to be as effective as antidepressant treatment for mild to moderate depressive illness, although patients receiving antidepressants may recover more quickly. General practitioners should allow patients to have their preferred treatment.

Influences on pre-hospital delay in the diagnosis of colorectal cancer: a systematic review

Colorectal cancer is a major global health problem, with survival varying according to stage at diagnosis. Delayed diagnosis can result from patient, practitioner or hospital delay. This paper reports the results of a review of the factors influencing pre-hospital delay - the time between a patient first noticing a cancer symptom and presenting to primary care or between first presentation and referral to secondary care. A systematic methodology was applied, including extensive searches of the literature published from 1970 to 2003, systematic data extraction, quality assessment and narrative data synthesis. Fifty-four studies were included. Patients' non-recognition of symptom seriousness increased delay, as did symptom denial. Patient delay was greater for rectal than colon cancers and the presence of more serious symptoms, such as pain, reduced delay. There appears to be no relationship between delay and patients' age, sex or socioeconomic status. Initial misdiagnosis, inadequate examination and inaccurate investigations increased practitioner delay. Use of referral guidelines may reduce delay, although evidence is currently limited. No intervention studies were identified. If delayed diagnosis is to be reduced, there must be increased recognition of the significance of symptoms among patients, and development and evaluation of interventions that are designed to ensure appropriate diagnosis and examination by practitioners.

The UK colorectal cancer screening pilot: results of the second round of screening in England

An evaluation of the second round of faecal occult blood (FOB) screening in the English site of the UK Colorectal Cancer Screening Pilot (comprising the Bowel Cancer Screening Pilot based in Rugby, general practices in four Primary Care Trusts, and their associated hospitals) was carried out. A total of 127 746 men and women aged 50–69 and registered in participating general practices were invited to participate. In all, 15.9% were new invitees not included in the previous round. A total of 52.1% of invitees returned a screening kit. Uptake varied with gender, age, and level of deprivation; was lower than in the first round (51.9 vs 58.5% P<0.0001), but was high (81.1%) in those who had participated in the first round with a negative result. Test positivity was 1.77%, significantly higher than in the first round, and the detection rate of neoplasia similar (5.67 per 1000), resulting in a lower positive predictive value. The sensitivity of FOBt in the first round was estimated as 57.7–64.4%. There was a significant impact on workload, particularly on endoscopy services. The cancer detection rate (0.94 per 1000) was lower than in the first round. Effort will be required to minimise inequalities in uptake, and to ensure adequate capacity of endoscopy services.

Morpholino and phosphorothioate antisense oligomers compared in cell-free and in-cell systems

Morpholino and phosphorothioate (S-DNA) antisense oligos were compared in both cell-free and in-cell translation systems. In the most stringent test of specificity in the cell-free system, a globin-targeted S-DNA oligo was found to inhibit its target sequence at concentrations of 10 nM and above, but the sequence-specific component of this inhibition dropped below 50% at concentrations of 100 nM and above. A corresponding Morpholino oligo achieved even higher inhibition at 10 nM, but in contrast to the S-DNA, with the Morpholino, the sequence-specific component of this inhibition remained above 93% at a concentration of 3000 nM. In this same cell-free test system, several S-DNA oligos exhibited substantial undesired nonantisense effects at concentrations of 300 nM and above, whereas corresponding Morpholino oligos exhibited little or no nonantisense activity through a concentration of 3000 nM. In scrape-loaded HeLa cells, both globin-targeted and HBV-targeted S-DNAs (both antisense and control oligos) generally failed to achieve significant translational inhibition at extracellular concentrations up to 3000 nM. In contrast, the Morpholino oligos achieved effective and specific translational inhibition at extracellular concentrations ranging from 30 nM to 3000 nM.

Stable ultrahigh-density magneto-optical recordings using introduced linear defects

The stability of data bits in magnetic recording media at ultra-high densities is compromised by the thermal 'flips'--magnetic spin reversals--of nano-sized spin domains, which erase the stored information. Media that are magnetized perpendicular to the plane of the film, such as ultrathin cobalt films or multilayered structures, are more stable against thermal self-erasure than conventional memory devices. In this context, magneto-optical memories seem particularly promising for ultrahigh-density recording on portable disks, and bit densities of approximately 100 Gbit inch(-2) (ref. 7) have been demonstrated using recent advances in the bit writing and reading techniques. But the roughness and mobility of the magnetic domain walls prevents closer packing of the magnetic bits, and therefore presents a challenge to reaching even higher bit densities. Here we report that the strain imposed by a linear defect in a magnetic thin film can smooth rough domain walls over regions hundreds of micrometres in size, and halt their motion. A scaling analysis of this process, based on the generic physics of disorder-controlled elastic lines, points to a simple way by which magnetic media might be prepared that can store data at densities in excess of 1 Tbit inch(-2).

Restoration of hemoglobin A synthesis in erythroid cells from peripheral blood of thalassemic patients

Mononuclear cells from peripheral blood of thalassemic patients were treated with morpholino oligonucleotides antisense to aberrant splice sites in mutant beta-globin precursor mRNAs (pre-mRNAs). The oligonucleotides restored correct splicing and translation of beta-globin mRNA, increasing the hemoglobin (Hb) A synthesis in erythroid cells from patients with IVS2-654/beta(E), IVS2-745/IVS2-745, and IVS2-745/IVS2-1 genotypes. The maximal Hb A level for repaired IVS2-745 mutation was approximately 30% of normal; Hb A was still detectable 9 days after a single treatment with oligonucleotide. Thus, expression of defective beta-globin genes was repaired and significant level of Hb A was restored in a cell population that would be targeted in clinical applications of this approach.

A specificity comparison of four antisense types: morpholino, 2'-O-methyl RNA, DNA, and phosphorothioate DNA

Cell-free translation studies were carried out to compare the efficacy and specificity of four antisense structural types: DNA, phosphorothioate DNA (S-DNA), 2'-O-methyl RNA, and Morpholino oligos, a novel antisense structural type. In these studies, translational inhibition was assessed for two 20-mers of each structural type, where one 20-mer was complementary to its target sequence in rabbit alpha-globin mRNA and the other 20-mer contained three mispairs to that same target sequence. It is shown that at low concentration of antisense oligomer (50 nM) all four types provide high specificity, but the Morpholino oligos and 2'-O-methyl RNA afford better efficacy. At high oligomer concentration (3.5 microM), all four types provide high efficacy, but the Morpholino oligos and 2'-O-methyl RNA provide substantially better specificity than the DNA and S-DNA.

Interval cancers in a FOBT-based colorectal cancer population screening programme: implications for stage, gender and tumour site

BACKGROUND

Between 2000 and 2007, a demonstration pilot of biennial guaiac faecal occult blood test (GFOBT) screening was carried out in Scotland.

METHODS

Interval cancers were defined as cancers diagnosed within 2 years (ie, a complete screening round) of a negative GFOBT. The stage and outcome of the interval cancers were compared with those arising contemporaneously in the non-screened Scottish population. In addition, the gender and site distributions of the interval cancers were compared with those in the screen-detected group and the non-screened population.

RESULTS

Of the cancers diagnosed in the screened population, interval cancers comprised 31.2% in the first round, 47.7% in the second, and 58.9% in the third, although this was due to a decline in the numbers of screen-detected cancers rather than an increase in interval cancers. There were no consistent differences in the stage distribution of interval cancers and cancers from the non-screened population, and, in all three rounds, both overall and cancer-specific survival were significantly better for patients diagnosed with interval cancers (p<0.01). The percentage of cancers arising in women was significantly higher in the interval cancer group (50.2%) than in either the screen-detected group (35.3%, p<0.001) or the non-screened group (40.6%, p<0.001). In addition, the proportion of both right-sided and rectal cancers was significantly higher in the interval cancer group than in either the screen-detected (p<0.001) or non-screened (p<0.004) groups.

CONCLUSIONS

Although GFOBT screening is associated with substantial interval cancer rates that increase with screening round, the absolute numbers do not. Interval cancers are associated with a better prognosis than cancers arising in a non-screened population, and GFOBT appears to preferentially detect cancers in men and the left side of the colon at the expense of cancers in women and in the right colon and rectum.

Systematic review of factors influencing patient and practitioner delay in diagnosis of upper gastrointestinal cancer

As knowledge on the causation of cancers advances and new treatments are developed, early recognition and accurate diagnosis becomes increasingly important. This review focused on identifying factors influencing patient and primary care practitioner delay for upper gastrointestinal cancer. A systematic methodology was applied, including extensive searches of the literature published from 1970 to 2003, systematic data extraction, quality assessment and narrative data synthesis. Included studies were those evaluating factors associated with the time interval between a patient first noticing a cancer symptom and presenting to primary care, between a patient first presenting to primary care and being referred to secondary care, or describing an intervention designed to reduce those intervals. Twenty-five studies were included in the review. Studies reporting delay intervals demonstrated that the patient phase of delay was greater than the practitioner phase, whilst patient-related research suggests that recognition of symptom seriousness is more important than recognition of the presence of the symptom. The main factors related to practitioner delay were misdiagnosis, application and interpretation of tests, and the confounding effect of existing disease. Greater understanding of patient factors is required, along with evaluation of interventions to ensure appropriate diagnosis, examination and investigation.

Zidovudine triphosphate and lamivudine triphosphate concentration-response relationships in HIV-infected persons

OBJECTIVE

To quantitate intracellular concentrations of zidovudine and lamivudine triphosphate and explore relationships with virologic and immunologic responses to antiretroviral therapy.

DESIGN

Eight antiretroviral-naive, HIV-infected persons with CD4 T cell counts > 100 x 10(6) cells/l, and HIV RNA in plasma > 5000 copies/ml participating in a prospective, randomized, open-label study of standard dose versus concentration-controlled therapy with zidovudine, lamivudine, and indinavir.

METHODS

Peripheral blood mononuclear cells and plasma were collected frequently throughout the study for quantitation of intracellular zidovudine triphosphate and lamivudine triphosphate concentrations, and zidovudine and lamivudine concentrations in plasma. CD4 T cells and HIV RNA in plasma (Roche Amplicor Ultrasensitive Assay) were measured at baseline and every 4 weeks throughout the study. Relationships among intracellular and plasma concentrations, and CD4 T cells and HIV RNA in plasma were investigated with regression analyses.

RESULTS

Significant relationships were observed between the intracellular concentrations of zidovudine triphosphate and lamivudine triphosphate and the baseline level of CD4 cells. Lamivudine triphosphate concentrations were related in a linear manner to the apparent oral clearance of lamivudine from plasma. A direct linear relationship was found between the intracellular concentrations of zidovudine triphosphate and lamivudine triphosphate. The percent change in CD4 cells during therapy and the rate of decline in HIV RNA in plasma were related to the intracellular concentrations of zidovudine triphosphate and lamivudine triphosphate.

CONCLUSION

These studies into the intracellular clinical pharmacology of nucleoside reverse transcriptase inhibitors illustrate potential clinical implications as determinants of therapeutic success. Moreover, these findings provide several leads and a strong impetus for future investigations with nucleoside reverse transcriptase inhibitors particularly when given in combination and sequentially.

The value of FDG positron emission tomography/computerised tomography (PET/CT) in pre-operative staging of colorectal cancer: a systematic review and economic evaluation

OBJECTIVES

In the UK, colorectal cancer (CRC) is the third most common malignancy (behind lung and breast cancer) with 37,514 cases registered in 2006: around two-thirds (23,384) in the colon and one-third (14,130) in the rectum. Treatment of cancers of the colon can vary considerably, but surgical resection is the mainstay of treatment for curative intent. Following surgical resection, there is a comprehensive assessment of the tumour, it's invasion characteristics and spread (tumour staging). A number of imaging modalities are used in the pre-operative staging of CRCs including; computerised tomography (CT), magnetic resonance imaging, ultrasound imaging and positron emission tomography (PET). This report examines the role of CT in combination with PET scanning (PET/CT 'hybrid' scan). The research objectives are: to evaluate the diagnostic accuracy and therapeutic impact of fluorine-18-deoxyglucose (FDG) PET/CT for the pre-operative staging of primary, recurrent and metastatic cancer using systematic review methods; undertake probabilistic decision-analytic modelling (using Monte Carlo simulation); and conduct a value of information analysis to help inform whether or not there is potential worth in undertaking further research.

DATA SOURCES

For each aspect of the research - the systematic review, the handsearch study and the economic evaluation - a database was assembled from a comprehensive search for published and unpublished studies, which included database searches, reference lists search and contact with experts. In the systematic review prospective and retrospective patient series (diagnostic cohort) and randomised controlled trials (RCTs) were eligible for inclusion. Both consecutive series and series that are not explicitly reported as consecutive were included.

REVIEW METHODS

Two reviewers extracted all data and applied the criteria independently and resolved disagreements by discussion. Data to populate 2 × 2 contingency tables consisting of the number of true positives, true negatives, false positives and false negatives using the studies' own definitions were extracted, as were data relating to changes in management. Fourteen items from the Quality Assessment of Diagnostic Accuracy Studies checklist were used to assess the methodological quality of the included studies. Patient-level data were used to calculate sensitivity and specificity with confidence intervals (CIs). Data were plotted graphically in forest plots. For the economic evaluation, economic models were designed for each of the disease states: primary, recurrent and metastatic. These were developed and populated based on a variety of information sources (in particular from published data sources) and literature, and in consultation with clinical experts.

RESULTS

The review found 30 studies that met the eligibility criteria. Only two small studies evaluated the use of FDG PET/CT in primary CRC, and there is insufficient evidence to support its routine use at this time. The use of FDG PET/CT for the detection of recurrent disease identified data from five retrospective studies from which a pooled sensitivity of 91% (95% CI 0.87% to 0.95%) and specificity of 91% (95% CI 0.85% to 0.95%) were observed. Pooled accuracy data from patients undergoing staging for suspected metastatic disease showed FDG PET/CT to have a pooled sensitivity of 91% (95% CI 87% to 94%) and a specificity of 76% (95% CI 58% to 88%), but the poor quality of the studies means the validity of the data may be compromised by several biases. The separate handsearch study did not yield any additional unique studies relevant to FDG PET/CT. Models for recurrent disease demonstrated an incremental cost-effectiveness ratio of £ 21,409 per quality-adjusted life-year (QALY) for rectal cancer, £ 6189 per QALY for colon cancer and £ 21,434 per QALY for metastatic disease. The value of handsearching to identify studies of less clearly defined or reported diagnostic tests is still to be investigated.

CONCLUSIONS

The systematic review found insufficient evidence to support the routine use of FDG PET/CT in primary CRC and only a small amount of evidence supporting its use in the pre-operative staging of recurrent and metastatic CRC, and, although FDG PET/CT was shown to change patient management, the data are divergent and the quality of research is generally poor. The handsearch to identify studies of less clearly defined or reported diagnostic tests did not find additional studies. The primary limitations in the economic evaluations were due to uncertainty and lack of available evidence from the systematic reviews for key parameters in each of the five models. In order to address this, a conservative approach was adopted in choosing DTA estimates for the model parameters. Probabilistic analyses were undertaken for each of the models, incorporating wide levels of uncertainty particularly for the DTA estimates. None of the economic models reported cost-savings, but the approach adopted was conservative in order to determine more reliable results given the lack of current information. The economic evaluations conclude that FDG PET/CT as an add-on imaging device is cost-effective in the pre-operative staging of recurrent colon, recurrent rectal and metastatic disease but not in primary colon or rectal cancers. There would be value in undertaking an RCT with a concurrent economic evaluation to evaluate the therapeutic impact and cost-effectiveness of FDG PET/CT compared with conventional imaging (without PET) for the pre-operative staging of recurrent and metastatic CRC.

Effect of gender, age and deprivation on key performance indicators in a FOBT-based colorectal screening programme

OBJECTIVES

To assess the effect of gender, age and deprivation on key performance indicators in a colorectal cancer screening programme.

SETTING

Between March 2000 and May 2006 a demonstration pilot of biennial guaiac faecal occult blood test (gFOBT) colorectal screening was carried out in North-East Scotland for all individuals aged 50-69 years.

METHODS

The relevant populations were subdivided, by gender, into four age groups and into five deprivation categories according to the Scottish Index of Multiple Deprivation (SIMD), and key performance indicators analysed within these groups.

RESULTS

In all rounds, uptake of the gFOBT increased with age (P < 0.001), decreased with increasing deprivation in both genders (P < 0.001), and was consistently higher in women than in men in all age and all SIMD groups. In addition, increasing deprivation was negatively associated with uptake of colonoscopy in men with a positive gFOBT (P < 0.001) although this effect was not observed in women. Positivity rates increased with age (P < 0.001) and increasing deprivation (P < 0.001) in both genders in all rounds, although they were higher in men than in women for all age and SIMD categories. Cancer detection rates increased with age (P < 0.001), were higher in men than in women in all age and SIMD categories, but were not consistently related to deprivation. In both genders, the positive predictive value (PPV) for cancer increased with age (P < 0.001) and decreased with increasing deprivation (P < 0.001) in all rounds and was consistently higher in men than in women in all age and SIMD categories.

CONCLUSIONS

In this population-based colorectal screening programme gender, age, and deprivation had marked effects on key performance indicators, and this has implications both for the evaluation of screening programmes and for strategies designed to reduce inequalities.

How should we measure informed choice? The case of cancer screening

Informed choice is increasingly recognised as important in supporting patient autonomy and ensuring that people are neither deceived nor coerced. In cancer screening the emphasis has shifted away from just promoting the benefits of screening to providing comprehensive information to enable people to make an informed choice. Cancer screening programmes in the UK now have policies in place which state that it is their responsibility to ensure that individuals are making an individual informed choice. There is a need to evaluate whether such policies mean that those people invited for screening are making informed choices, and how comprehensive information affects other variables such as uptake, cost effectiveness, and satisfaction. At the present time, there is no validated measure of informed choice in cancer screening. Such a measure could be used to evaluate the effectiveness of interventions to increase informed choice and levels of informed choice in a population invited for screening. It could encourage health professionals to be accountable. Factors important when measuring informed choice in cancer screening include an individual's understanding of the limitations of screening, the ability to make an autonomous choice, and the difference between choice and behaviour.

The ultimate speed of magnetic switching in granular recording media

In magnetic memory devices, logical bits are recorded by selectively setting the magnetization vector of individual magnetic domains either 'up' or 'down'. In such devices, the fastest and most efficient recording method involves precessional switching: when a magnetic field B(p) is applied as a write pulse over a period tau, the magnetization vector precesses about the field until B(p)tau reaches the threshold value at which switching occurs. Increasing the amplitude of the write pulse B(p) might therefore substantially shorten the required switching time tau and allow for faster magnetic recording. Here we use very short pulses of a very high magnetic field to show that under these extreme conditions, precessional switching in magnetic media supporting high bit densities no longer takes place at well-defined field strengths; instead, switching occurs randomly within a wide range of magnetic fields. We attribute this behaviour to a momentary collapse of the ferromagnetic order of the spins under the load of the short and high-field pulse, thus establishing an ultimate limit to the speed of deterministic switching and magnetic recording.