Digital dual-parameter data acquisition for SP2 hydrogen-filled proportional counters

Hydrogen-filled proportional counters perform well as neutron spectrometers in the energy region from a few tens of keV up to ∼1.5 MeV. Unfortunately, gamma rays also generate signals in these detectors. It is possible in principle to distinguish the two types of event via the rise time of their respective signal pulses, but the data acquisition system needed for this is complex to assemble and adjust if one uses conventional modular analogue electronics. In this work a digital sampling system, in conjunction with custom software, was used to measure and acquire amplitude and rise time data from type SP2 counters. The interpretation of the data was supported by a Monte Carlo calculation. The performance of the system is compared with that of a conventional 1-parameter analogue system, and the potential of the digital technique to supplant conventional methods is discussed.

Preclinic telephone consultations: an observational cohort study

Patients referred to secondary care for specialist respiratory review frequently undergo multiple hospital attendances for investigations and consultations. This study evaluated the potential of a preclinic telephone consultation and subsequent coordination of tests and face-to-face consultations to reduce hospital visits. Total hospital attendances were recorded for three cohorts (participants, non-participants and comparators) for 6 months from first specialist contact. Patients completed the medical interview satisfaction scale-21 (MISS-21). The study showed that a preclinic telephone consultation can significantly reduce hospital visits over a fixed period without reducing patient satisfaction. In total, 20.8% of the participant group had three or more hospital attendances compared with 42.9% of the non-participant group (p = 0.001) and 44.7% of the comparator group (p = 0.002). Participants had fewer follow up visits and lower rates of non-attendance/late rearrangement of appointments. This service reduces unnecessary hospital visits, seems to improve patient compliance and may save costs associated with non-attendance and follow up consultations.

Barriers to the implementation of self management support in long term lung conditions

Background Self-management improves outcomes in asthma and COPD and is strongly recommended in national and international guidelines; however implementation of the guidelines such as use of written action plans in practice is often poor. Setting A questionnaire survey was undertaken to identify the healthcare professional barriers to implementation of self-management for asthma and COPD in West London. Question Why is self-management education not being undertaken in respiratory conditions? Methods A questionnaire was designed to elicit healthcare professionals' views about barriers to implementation of self-management in asthma and COPD. Results Response rates were 33% (58/175). Results showed strong support for guideline recommendations, however implementation was patchy. Seventy six percent of respondents discussed asthma self-management with patients; however only 47.8% of patients received a written action plan. For COPD patients, 55.1% discussed self-management, with 41% receiving a written action plan. In COPD, there was greater GP involvement and less delegation of self-management. Barriers to implementation included patient factors (compliance, literacy and patient understanding), time constraints and insufficient resources. Those who believed they had witnessed improved health outcomes with self-management (53%, 31/58) were more likely to give written action plans (78%, 24/31, 'nearly always/sometimes' gave written action plans), Nearly a third of healthcare professionals reported lacking confidence in constructing written action plans (33% 19/58; GPs 43%, nurses 43%). Conclusion Despite overwhelming evidence self-management support is still not being implemented into routine clinical practice, identified barriers included time constraints, lack of training, lack of belief in patients ability to self-manage and lack of confidence completing self-management plans. Practice implications These issues need to be addressed if self-management support is to be delivered in a meaningful and effective way.

Evaluation of a paper and electronic pictorial COPD action plan

Personalised written action plans are increasingly regarded as an important component of chronic obstructive pulmonary disease (COPD) self-management support and yet they may not be understood by those with limited literacy skills. This study was designed to produce a comprehensible pictorial COPD action plan for use by patients and health care professionals. With advice from a group of doctors and nurses a 'standard' written COPD action plan was translated by a medical artist into a series of pictorial images. These were assessed using the techniques of guessability and translucency in 21 adults attending a COPD clinic in a London hospital. Guessability and translucency scores show that pictograms were reasonably well understood, with only 3 pictograms showing low score in both guessability and translucency questionnaires. These included images depicting increased sputum production, swollen ankles, and use of extra doses of reliever medication. However, after brief spoken reinforcement about self-management, most patients could use the pictorial plan to suggest appropriate self-management behaviour such as when to access medical care. We have developed a pictorial COPD action plan. Pictorial methods represent an effective method of reinforcing the spoken word for all ranges of literacy.

Interleukin-6⁻¹⁷⁴ and tumor necrosis factor α⁻³⁰⁸ polymorphisms enhance cytokine production by human macrophages exposed to respiratory viruses

Interleukin-6⁻¹⁷⁴ (IL-6⁻¹⁷⁴) and tumor necrosis factor α⁻³⁰⁸ (TNFα⁻³⁰⁸) are high-cytokine-producing genotypes that are known to increase the susceptibility to infectious diseases, but their influence on cytokine production induced by respiratory viruses is unknown. We exposed human monocyte-derived macrophages from IL-6⁻¹⁷⁴, TNFα⁻³⁰⁸, and normal genotype donors to different respiratory viruses. Respiratory syncytial virus (RSV) stimulation was associated with higher IL-6 concentrations in IL-6⁻¹⁷⁴ donors than in normal donors (P = 0.015); 2 of 7 (29%) polymorphic donors were poor responders compared with 6 of 7 (86%) normal donors (P = 0.002). Adenovirus, influenza virus, and RSV stimulations were associated with higher TNFα concentrations in TNFα⁻³⁰⁸ donors than in normal donors (P = 0.03, <0.01, <0.01). A similar trend was seen with rhinovirus stimulation, but this was not significant. These results show that IL-6⁻¹⁷⁴ and TNFα⁻³⁰⁸ gene polymorphisms lead to enhanced production of the respective cytokines when exposed to specific respiratory viruses. This, in turn, may influence the susceptibility to, severity of, and recovery from respiratory virus infections, or influence the immune response to and reactogenicity of viral vaccines.

Are evaluated respiratory service developments implemented into clinical practice?

INTRODUCTION

Evaluation of the way in which respiratory care is delivered is increasingly recognised to be an important area for research. When service developments are reported, it is not always clear whether they are subsequently implemented within the reporting institution, and if not why not.

METHODS

3281 abstracts from three specialist journals and one general journal were reviewed, and 36 reported evaluated service developments identified. The authors of each of these were approached to determine whether the reported service developments were in use in their institution.

RESULTS

30 of the 36 authors responded (83%). 10 reports were of sharing care with nurses and five with other health professionals, and the remainder involved new technologies, education, patient information or guideline implementation. 15/30 had implemented the reported development into practice, 11 of which were implemented immediately. Delays were due to staffing, funding and organisational issues. 10/15 studies were not put into practice, the main reason being that the key person had left. Four respondents embarked upon further study to confirm their preliminary published findings.

CONCLUSIONS

Reports of apparently positive service developments are only implemented in approximately one-half of institutions reporting the development. In a third of cases, non-implementation reflects the original authors believing that further study is necessary to confirm effectiveness.

Recent developments in radionuclide neutron source emission rate measurements at the National Physical Laboratory

This paper outlines the key features of the new manganese bath facility of the National Physical Laboratory and describes the measurements performed to characterise and validate the facility. Other developments have focused on the use of MCNP to calculate the fraction of neutrons captured by nuclei other than manganese and the fraction escaping from the bath. This has highlighted the large difference in the oxygen(n,alpha) capture fraction when different cross-section evaluations are applied. This can change the value obtained for the neutron emission rate of a source by up to 0.8%.

A nurse led intermediate care package in patients who have been hospitalised with an acute exacerbation of chronic obstructive pulmonary disease

OBJECTIVES

To determine the effects of a nurse led intermediate care programme in patients who have been hospitalised with an acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

DESIGN

Randomised controlled trial.

SETTING

Community and hospital care in west London.

PARTICIPANTS

122 patients with COPD.

INTERVENTION

A care package incorporating initial pulmonary rehabilitation and self-management education, provision of a written, personalised COPD action plan, monthly telephone calls and 3 monthly home visits by a specialist nurse for a period of 2 years.

MAIN OUTCOME MEASURE

Hospital readmission rate.

SECONDARY OUTCOMES

Unscheduled primary care consultations and quality of life.

RESULTS

There were no differences in hospital admission rates or in exacerbation rates between the two groups. Self-management of exacerbations was significantly different and the intervention group were more likely to be treated with oral steroids alone or oral steroids and antibiotics, and the initiators of treatment for exacerbations were statistically more likely to be the patients themselves. 12 patients in the control group died during the 2 year period, eight as a result of COPD, compared with six patients in the intervention group, of whom one died from COPD. This is a significant difference. When the numbers were adjusted to reflect the numbers still alive at 2 years, in the intervention group patients reported a total of 171 unscheduled contacts with their general practitioner (GP) and in the control group, 280 contacts. The number needed to treat was 0.558--ie, for every one COPD patient receiving the intervention and self-management advice, there were 1.79 fewer unscheduled contacts with the GP.

CONCLUSIONS

An intermediate care package incorporating pulmonary rehabilitation, self-management education and the receipt of a written COPD action plan, together with regular nurse contact, is associated with a reduced need for unscheduled primary care consultations and a reduction in deaths due to COPD but did not affect the hospital readmission rate.

Small interfering RNA profiling reveals key role of clathrin-mediated endocytosis and early endosome formation for infection by respiratory syncytial virus

Respiratory syncytial virus (RSV) is a common cause of respiratory tract infections in infants and the elderly. Like many other pH-independent enveloped viruses, RSV is thought to enter at the cell surface, independently of common endocytic pathways. We have used a targeted small interfering RNA (siRNA) library to identify key cellular genes involved in cytoskeletal dynamics and endosome trafficking that are important for RSV infection. Surprisingly, RSV infection was potently inhibited by siRNAs targeting genes associated with clathrin-mediated endocytosis, including clathrin light chain. The important role of clathrin-mediated endocytosis was confirmed by the expression of well-characterized dominant-negative mutants of genes in this pathway and by using the clathrin endocytosis inhibitor chlorpromazine. We conclude that, while RSV may be competent to enter at the cell surface, clathrin function and endocytosis are a necessary and important part of a productive RSV infection, even though infection is strictly independent of pH. These findings raise the possibility that other pH-independent viruses may share a similar dependence on endocytosis for infection and provide a new potential avenue for treatment of infection.

Characterization and utilization of a Bonner sphere set based on gold activation foils

Bonner sphere (BS) sets which use activation foils as the central thermal neutron sensor have advantages over active BS systems in certain environments, for example, pulsed fields, or fields with high photon components. In such environments, they may be the only type of neutron spectrometer which can be used. This paper describes work, using both measurements and calculations, to validate the response functions for a BS set based on gold activation foils. As an illustration of the use of such a system, a measurement is described of the contaminant neutron spectrum in the treatment room of a 21 MV hospital linear accelerator providing photon beams for radiotherapy.

Investigation of combined unfolding of neutron spectra using the UMG unfolding codes

An investigation of the simultaneous unfolding of data from neutron spectrometers using the UMG codes MAXED and GRAVEL has been performed. This approach involves combining the data from the spectrometers before unfolding, thereby performing a single combined unfolding of all the data to yield a final combined spectrum. The study used measured data from three proton recoil counters and also Bonner sphere and proton recoil counter responses calculated from their response functions. In each case, the spectrum derived from combined unfolding is compared with either the spectrum obtained from merging the independently unfolded spectra or the spectrum used to calculate the responses. The advantages and disadvantages of this technique are discussed.

The content of 250Cf and 248Cm in 252Cf neutron sources and the effect on the neutron emission rate

One of the most common radionuclide neutron sources used for the calibration of detectors is (252)Cf. However, these sources also contain (250)Cf, which is present in the material from which the sources are made, and (248)Cm, which is formed as the daughter of (252)Cf via alpha-decay. Both decay by spontaneous fission with longer half-lives than (252)Cf. Consequently, as the source becomes older, the emission rate does not follow the decay curve of (252)Cf. Fits have been made to emission rate measurements of (252)Cf sources at NPL spanning over 30 y to deduce their (250)Cf and (248)Cm content. The emission rate of a source can be significantly underestimated if the presence of (250)Cf and (248)Cm is not taken into account, and this has been investigated for a typical (252)Cf source. The importance of this problem to other calibration laboratories and users of (252)Cf sources is emphasised.

Respiratory syncytial virus F envelope protein associates with lipid rafts without a requirement for other virus proteins

Like many enveloped viruses, human respiratory syncytial virus (RSV) assembles at and buds from lipid rafts. Translocation of the envelope proteins to these membrane subdomains is essential for production of infectious virus, but the targeting mechanism is poorly understood and it is not known if other virus proteins are required. Here we demonstrate that F protein of RSV intrinsically targets to lipid rafts without a requirement for any other virus protein, including the SH and G envelope proteins. Recombinant virus deficient in SH and G but retaining F protein expression was used to demonstrate that F protein still localized in rafts in both A549 and HEp-2 cells. Expression of a recombinant F gene by use of plasmid vectors demonstrated that F contains its own targeting domain and localized to rafts in the absence of other virus proteins. The domain responsible for translocation was then mapped. Unlike most other virus envelope proteins, F is unusual since the target signal is not contained within the cytoplasmic domain nor did it involve fatty acid modified residues. Furthermore, exchange of the transmembrane domain with that of the vesicular stomatitis virus G protein, a nonraft protein, did not alter F protein raft localization. Taken together, these data suggest that domains present in the extracellular portion of the protein are responsible for lipid raft targeting of the RSV F protein.

How is difficult asthma managed?

Most patients with asthma can be easily treated. Some have difficult asthma; in some because the diagnosis is erroneous, in others because of comorbidity or noncompliance. A European Respiratory Society Task Force has called for an integrated approach for these patients, and positive results have been reported using protocols. In the UK, there is no overall understanding of the size of this problem, or how these patients are managed. A postal survey of 683 consultant members of the British Thoracic Society designed to elicit respondents' views on how they would manage four clinical scenarios was conducted. There was a 50.4% response rate. Few reported a uniform approach to the investigation of such patients. The availability of allied healthcare professionals was variable. The 21 consultant respiratory physicans, reporting a special interest in difficult asthma, were significantly more likely to objectively assess compliance, perform skin-prick tests and to utilise a liaison psychiatrist than those without an expressed special interest in asthma. Many reported difficulty in accessing psychologists, liaison psychiatrists and social workers. Approaches to the diagnosis and management of "vocal cord dysfunction" were variable. The results of this postal survey of specialist thoracic physicians in the UK suggest that a protocol for difficult asthma is not in widespread use and that access to necessary allied healthcare professionals is not uniform. Pulmonologists with a declared special interest in difficult asthma may have configured their services and approaches more in line with that proposed by the European Respiratory Society Task Force.

Modelling of neutron survey instrument performance and experimental validation of those calculated response data

Three moderator-type neutron survey instruments have been modelled for energy and angle dependence of the response, in greater detail than before. These response data have been verified by comparison with published experimental measurements and measurements made specifically for this project. Influences on the instrument response have also been investigated. These have included its mode-of-use and perturbations caused by variations in the instrument manufacture. The implications of these new response data have been assessed by an extensive programme of folding the responses with workplace energy distributions.

Characterisation of the IRSN CANEL/T400 facility producing realistic neutron fields for calibration and test purposes

The new CANEL/T400 facility has been set-up at the Institute for Radiological Protection and Nuclear Safety (IRSN) to produce a realistic neutron field. The accurate characterisation of this neutron field is mandatory since this facility will be used as a reference neutron source. For this reason an international measuring campaign, involving four laboratories with extensive expertise in neutron metrology and spectrometry, was organised through a concerted EUROMET project. Measurements were performed with Bonner sphere (BS) systems to determine the energy distribution of the emitted neutrons over the whole energy range (from thermal energy up to a few MeV). Additional measurements were performed with proton recoil detectors to provide detailed information in the energy region above 90 keV. The results obtained by the four laboratories are in agreement with each other and are compared with a calculation performed with the MCNP4C Monte-Carlo code. As a conclusion of this exercise, a reliable characterisation of the CANEL/T400 neutron field is obtained.

Angle dependence of response characteristics of neutron survey instruments

Neutron area survey instruments are designed to have an approximately isotropic response. In practice, the response cannot be perfectly isotropic for instruments that do not have spherical symmetry, and for all instruments it is modified by the inclusion of batteries, electronics, handles, etc. This affects the ability of the survey instrument to measure accurately an isotropic dose equivalent quantity. Measurements of the angle dependence of response for four of the most commonly used designs of survey instrument (Harwell 0949, Mark 7 NRM, NM2 and Studsvik 2202D) have been performed in a low-scatter room using radionuclide and monoenergetic neutron sources. The Monte Carlo code MCNP has been used to model the responses and to investigate their sensitivity to the polyethylene density, counting gas pressure and other manufacturing tolerances. Preliminary modelling results are presented here.

Practical implications of neutron survey instrument performance

Improvements have been made to the Monte Carlo modelling used to calculate the response of the neutron survey instruments most commonly used in the UK, for neutron energies up to 20 MeV. The improved modelling of the devices includes the electronics and battery pack, allowing better calculations of both the energy and angle dependence of response. These data are used to calculate the response of the instruments in rotationally and fully isotropic, as well as unidirectional fields. Experimental measurements with radionuclide sources and monoenergetic neutron fields have been, and continue to be made, to test the calculated response characteristics. The enhancements to the calculations have involved simulation of the sensitivity of the response to variations in instrument manufacture, and will include the influence of the user and floor during measurements. The practical implications of the energy and angle dependence of response, variations in manufacture, and the influence of the user are assessed by folding the response characteristics with workplace energy and direction distributions.

Incomplete Immune Reconstitution after Initiation of Highly Active Antiretroviral Therapy in Human Immunodeficiency Virus–Infected Patients with Severe CD4+Cell Depletion

Immune function was observed for 144 weeks in 643 human immunodeficiency virus (HIV)-infected subjects who (1) had nadir CD4+ cell counts of <50 cells/mm3, followed by a sustained increase to > or =100 cells/mm3 after the initiation of HAART, and (2) were enrolled in a randomized trial of continued azithromycin prophylaxis versus withdrawal for prevention of Mycobacterium avium complex disease. The median CD4+ cell count was 226 cells/mm3 at entry and 358 cells/mm3 at week 144. Anergy (80.2% of patients) and lack of lymphoproliferative response to tetanus toxoid (TT; 73%) after immunization and impaired antibody responses after receipt of hepatitis A (54%) and TT (86%) vaccines were considered to be evidence of impaired immune reconstitution. Receipt of azithromycin did not have an effect on CD4+ cell count but was associated with higher rates of delayed-type hypersensitivity responses to TT (25% of subjects who received azithromycin vs. 15% of those who did not; P=.009) and mumps skin test antigen (29% vs. 17%; P=.001). Although the subjects had only partial responses to immune function testing, the rate of opportunistic infections was very low, and none of the tests was predictive of risk.

Airway epithelial inflammatory responses and clinical parameters in COPD

This study examined inflammatory responses from primary cultured human bronchial epithelial cells in chronic obstructive pulmonary disease (COPD) and the clinical factors modulating them. Epithelial cells from bronchoscopic biopsies from 14 patients with COPD ((mean +/- SD) age 74.6 +/- 5.7 yrs, forced expiratory volume in one second (FEV1) 1.21 +/- 0.36 L, FEV1 %, predicted 51.1 +/- 15.8%, 51.5 +/- 24.0 pack-yrs of smoking, inhaled steroid dosage 1237.5 +/- 671.0 microg x day(-1), Medical Research Council (MRC) dyspnoea score 3.18 +/- 1.33) and eight current/exsmokers with normal pulmonary function (age 60.4 +/- 13.5 yrs, FEV1 2.66 +/- 1.27 L, FEV1 % pred 89.6 +/- 17.7%, 49 +/- 44 pack-yrs of smoking, MRC dyspnoea score 1 +/- 0) were grown in primary culture and exposed to 50 ng x mL(-1) tumour necrosis factor-alpha. Stimulated COPD cells produced significantly more interleukin (IL)-6 at 24 and 48 h, and IL-8 at 6 and 24 h than unstimulated COPD cells. This response was not seen in cells from current/exsmokers. IL-6 and IL-8 production was lower in COPD patients taking inhaled steroids. Following an inflammatory stimulus, bronchial epithelial cells in chronic obstructive pulmonary disease show a significant cytokine response not seen in smokers with normal pulmonary function and this may be modified by inhaled steroid therapy.