Harvested rainwater quality: the importance of appropriate design

This paper summarises the physicochemical and microbiological quality of water from a rainwater harvesting (RWH) system in a UK-based office building. 7 microbiological and 34 physicochemical parameters were analysed during an 8 month period. Physicochemically, harvested rainwater quality posed little health risk; most parameters showed concentrations below widely used guideline levels for drinking water. However, RWH system components (e.g. fittings and down pipes) appear to be affected soft water corrosion, resulting in high concentrations of some metals (copper, zinc and aluminium). This suggests the material selection of such fittings should be considered keeping in view the hardness of rainwater of an area. Microbiologically, Cryptosporidium, Salmonella and Legionella were not present in the samples analysed. However, faecal coliform counts were high at the beginning of the study, but did decrease over time in weak correlation with increasing pH. Enterococcus faecalis displayed counts consistently above UK rainwater harvesting standards. Inappropriate roof and rainwater good design, as well as material selection appear to be responsible for the reduced microbial quality, as they promoted contributions from avian sources and inhibited cleaning activities. Building and RWH system designs require greater consideration of local factors, which are critical for optimising harvested rainwater quality, to prevent both the development of contaminated sediments and health impacts.

Trastuzumab for the treatment of primary breast cancer in HER2-positive women: a single technology appraisal

This paper presents a summary of the evidence review group (ERG) report into the the clinical and cost-effectiveness of trastuzumab for the treatment of primary breast cancer in human epidermal growth factor 2 (HER2)-positive women based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The manufacturer's scope restricts the intervention to intravenous trastuzumab given for 1 year after surgery and after the completion of standard adjuvant chemotherapy, and the comparator to standard therapy without trastuzumab. The clinical rationale for the duration of treatment in the scope is open to question and leads to the exclsuion of one potentially relevant trial. The submitted evidence reports that the 3-weekly regimen of trastuzumab produced a relative reduction in all-cause mortality of 24-33%. Meta-analysis of all available studies based on 12 months of trastuzumab showed that there was a statistically significant 30% relative improvement in overall survival using the 3-weekly regimen. A study looking at weekly cycles of trastuzumab, excluded in the manufacturer's submission, produced a relative reduction in all-cause mortality of 59%, which was not statistically significant. All included studies showed a statistically significant difference in the risk of recurrence or death from any cause (disease-free survival), favouring trastuzumab. There was a statistically significant increase in the relative risk of a serious adverse event in women treated with 3-weekly cycles of trastuzumab, with no excess toxicity in the study evaluating weekly cycles. Estimates of cost-effectiveness provided by the manufacturer were based on data from the HERA trial using the 3-weekly regimen of trastuzumab. The economic model was a state-transition model that compared the lifetime impact of adding 1 year of trastuzumab therapy to standard care with standard care alone. The initial cost-effectiveness estimate was 5687 pounds per additional quality-adjusted life-year (QALY) gained, rising to a maximum of 8689 pounds upon one-way sensitivity analysis. The base-case estimate of cost-effectiveness was subsequently revised by the manufacturer, resulting in an estimated incremental cost per additional QALY gained of 2387 pounds. A number of assumptions behind the manufacturer's model may be optimistic and could mean that the incremental costs per QALY gained were underestimated. Additional analysis carried out by the evidence review group concluded that the incremental cost-effectiveness ratio (ICER) is expected to be around 20,000 pounds to 30,000 pounds. The addition of potential long-term cardiac events could push the ICER above 30,000 pounds, although there is no long-term evidence to date surrounding this issue. In addition, the small study excluded from the manufacturer's submission raises the possibility of an equally effective but shorter regimen, incurring lower cost and toxicity and with greater patient convenience. The guidance issued by NICE in June 2006 as a result of the STA states that trastuzumab, given at 3-week intervals for 1 year or until disease recurrence, is recommended as a treatment option for women with early-stage HER2-positive breast cancer following surgery, chemotherapy and radiotherapy.

Efficient recovery of HLA class I expression in human tumor cells after beta2-microglobulin gene transfer using adenoviral vector: implications for cancer immunotherapy

Here we report a successful use of a non-replicating adenovirus expressing the wild-type human beta2m gene in recovery of normal human leucocyte antigen (HLA) class I expression in beta2m-null cancer cells. Total loss of HLA class I expression in these cell lines is caused by a mutation in beta2m gene and a loss of heterozygosity in chromosome 15 carrying another copy of that gene. Normal HLA class I expression on the tumour cell surface is critical for the successful outcome of cancer immunotherapy as T cells can only recognize tumour-derived peptides in a complex with self-HLA class I molecules. In this report we characterize the newly generated adenoviral vector AdCMVbeta2m and demonstrate an efficient beta2m gene transfer in tumour cell lines of different histological origin, including melanoma, prostate and colorectal carcinoma. The beta2m re-expression lasted for an extended period of time both in vitro and in vivo in human tumour xenograft transplants. We propose that in a subset of cancer patients with structural defect in beta2m gene or chromosome 15, the adenoviral-mediated recovery (or even increase) of HLA class I expression on tumour cells in combination with vaccination or adoptive T-cell therapy can provide a complementary approach to improve the clinical efficacy of cancer immunotherapy.

Trastuzumab for the treatment of primary HER2-positive breast cancer in HER2-positive women: a single technology appraisal

This paper presents a summary of the evidence review group (ERG) report into the the clinical and cost-effectiveness of trastuzumab for the treatment of primary breast cancer in human epidermal growth factor 2 (HER2)-positive women based upon a review of the manufacturer’s submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The manufacturer’s scope restricts the intervention to intravenous trastuzumab given for 1 year after surgery and after the completion of standard adjuvant chemotherapy, and the comparator to standard therapy without trastuzumab. The clinical rationale for the duration of treatment in the scope is open to question and leads to the exclsuion of one potentially relevant trial. The submitted evidence reports that the 3-weekly regimen of trastuzumab produced a relative reduction in all-cause mortality of 24–33%. Meta-analysis of all available studies based on 12 months of trastuzumab showed that there was a statistically significant 30% relative improvement in overall survival using the 3-weekly regimen. A study looking at weekly cycles of trastuzumab, excluded in the manufacturer’s submission, produced a relative reduction in all-cause mortality of 59%, which was not statistically significant. All included studies showed a statistically significant difference in the risk of recurrence or death from any cause (disease-free survival), favouring trastuzumab. There was a statistically significant increase in the relative risk of a serious adverse event in women treated with 3-weekly cycles of trastuzumab, with no excess toxicity in the study evaluating weekly cycles. Estimates of cost-effectiveness provided by the manufacturer were based on data from the HERA trial using the 3-weekly regimen of trastuzumab. The economic model was a state-transition model that compared the lifetime impact of adding 1 year of trastuzumab therapy to standard care with standard care alone. The initial cost-effectiveness estimate was £5687 per additional quality-adjusted life-year (QALY) gained, rising to a maximum of £8689 upon one-way sensitivity analysis. The base-case estimate of cost-effectiveness was subsequently revised by the manufacturer, resulting in an estimated incremental cost per additional QALY gained of £2387. A number of assumptions behind the manufacturer’s model may be optimistic and could mean that the incremental costs per QALY gained were underestimated. Additional analysis carried out by the evidence review group concluded that the incremental cost-effectiveness ratio (ICER) is expected to be around £20,000 to £30,000. The addition of potential long-term cardiac events could push the ICER above £30,000, although there is no long-term evidence to date surrounding this issue. In addition, the small study excluded from the manufacturer’s submission raises the possibility of an equally effective but shorter regimen, incurring lower cost and toxicity and with greater patient convenience. The guidance issued by NICE in June 2006 as a result of the STA states that trastuzumab, given at 3-week intervals for 1 year or until disease recurrence, is recommended as a treatment option for women with early-stage HER2-positive breast cancer following surgery, chemotherapy and radiotherapy.

A framework for supporting rainwater harvesting in the UK

Numerous policy vehicles have been introduced in the UK promoting the use of rainwater harvesting (RWH). However, an 'implementation deficit' exists where legislation limits action by failing to provide adequate support mechanisms. This study uses an interdisciplinary approach to construct a framework to address the issue of overcoming this deficit. Evidence bases have identified six deficit categories, which confirm a lack of enabling of stakeholders. Outline recommendations, such as coordinated information provision and reconsideration of incentive schemes are made in relation to these categories to complete the framework for supporting RWH in the UK.

Gully hotspot contribution to landscape methane (CH4) and carbon dioxide (CO2) fluxes in a northern peatland

Peatlands are long term carbon catchments that sink atmospheric carbon dioxide (CO(2)) and source methane (CH(4)). In the uplands of the United Kingdom ombrotrophic blanket peatlands commonly exist within Calluna vulgaris (L.) dominated moorland ecosystems. These landscapes contain a range of topographical features that influence local hydrology, climate and plant community composition. In this study we examined the variation in ecosystem CO(2) respiration and net CH(4) fluxes from typical plant-soil systems in dendritic drainage gullies and adjacent blanket peat during the growing season. Typically, Eriophorum spp., Sphagnum spp. and mixed grasses occupied gullies while C. vulgaris dominated in adjacent blanket peat. Gross CO(2) respiration was highest in the areas of Eriophorum spp. (650+/-140 mg CO(2) m(-2) h(-1)) compared to those with Sphagnum spp. (338+/-49 mg CO(2) m(-2) h(-1)), mixed grasses (342+/-91 mg CO(2) m(-2) h(-1)) and C. vulgaris (174+/-63 mg CO(2) m(-2) h(-1)). Measurements of the net CH(4) flux showed higher fluxes from the Eriophorum spp (2.2+/-0.6 mg CH(4) m(-2) h(-1)) locations compared to the Sphagnum spp. (0.6+/-0.4 mg CH(4) m(-2) h(-1)), mixed grasses (0.1+/-0.1 mg CH(4) m(-2) h(-1)) and a negligible flux detected from C. vulgaris (0.0+/-0.0 mg CH(4) m(-2) h(-1)) locations. A GIS approach was applied to calculate the contribution of gullies to landscape scale greenhouse gas fluxes. Findings from the Moor House National Nature Reserve in the UK showed that although gullies occupied only 9.3% of the total land surface, gullies accounted for 95.8% and 21.6% of the peatland net CH(4) and CO(2) respiratory fluxes, respectively. The implication of these findings is that the relative contribution of characteristic gully systems need to be considered in estimates of landscape scale peatland greenhouse gas fluxes.

Rapid photoreflectance spectroscopy for strained silicon metrology

We present an improved photoreflectance (PR) spectroscopy technique upon the prior art in providing a rapid acquisition method of the PR spectrum in a simultaneous and multiplexed manner. Rapid PR (RPR) application is the on-line monitoring of strained silicon. Shrinkage in the silicon bandgap is measured and converted to strain, using theoretical models. Experimental RPR results are in good correlation with Raman spectroscopy.

Taxanes for the adjuvant treatment of early breast cancer: systematic review and economic evaluation

OBJECTIVES

To estimate the clinical effectiveness and cost-effectiveness of docetaxel and paclitaxel compared with non-taxane, anthracycline-containing chemotherapy regimens, for the adjuvant treatment of women with early-stage breast cancer.

DATA SOURCES

Major electronic databases were searched between October 2005 and February 2006.

REVIEW METHODS

A systematic review of the literature on adjuvant taxane versus anthracycline non-taxane chemotherapy for women with early breast cancer was undertaken. A mathematical model was developed to synthesise the available data on costs, disease-free survival and health-related quality of life (HRQoL) of patients receiving taxane-containing chemotherapy versus non-taxane-containing chemotherapy.

RESULTS

Eight of the 11 selected trials (six docetaxel and five paclitaxel) reported a significant improvement in disease-free survival (DFS) or time to recurrence (TTR) for taxanes over comparator regimens. Docetaxel was associated with more adverse events than paclitaxel, most notably febrile neutropenia. Taxanes produced cardiotoxicity, although this was not reported to be greater than for anthracycline comparator arms in all trials. Treatment-related deaths were uncommon. Where reported, all chemotherapy regimens caused HRQoL to deteriorate during treatment. Following treatment, there were no clinically significant differences between taxane and comparator treatment groups. There were few data available comparing licensed regimens of taxanes with chemotherapy regimens commonly used in the UK. The three trials selected as the basis for the economic analysis were those that used the taxanes in accordance with current UK marketing authorisation and had also reported in full. The estimated incremental cost-effectiveness ratio for docetaxel compared to FAC6, based on the BCIRG 001 study, is 12,000 pounds (7000-39,000 pounds) and for paclitaxel compared with Adriamycin/cyclophosphamide, based on the NSABP B28 and CALGB 9344 studies, is 43,000 pounds (16,000 pounds-dominated) and 39,000 pounds (12,000 pounds-dominated), respectively. However, the comparators used in these trials restrict the generalisability of the results, as they do not conform to current standard care in the UK, typically FEC6 and E4-CMF4. An exploratory indirect comparison shows that the benefits of taxane containing regimens compared to regimens in current use in the UK is subject to large uncertainty due to the lack of direct trial comparisons between these interventions. Assumptions regarding the benefits in the taxane arm after the trial follow-up period and the annual rate of recurrence in this period have the most significant influence on the ICER.

CONCLUSIONS

There is a large degree of heterogeneity in the evidence base for the effectiveness of taxane- compared with non-taxane-containing regimens in terms of the interventions, comparators and populations. Eight of the 11 trials providing effectiveness data reported a significant improvement in DFS or TTR for taxanes over comparator regimens. The remaining three trials found no significant differences between the groups in DFS/TTR. The cost-effectiveness results suggest that the cost per quality-adjusted life-year for taxane- compared with non-taxane-containing chemotherapy varies between 12,000 pounds and 43,000 pounds, depending on the taxane under consideration and the specific trial used as the basis of the analysis. However, the comparators used in these trials do not conform to current standard care in the UK. More research is needed, comparing taxanes used in line with their current UK marketing authorisation and with anthracycline-containing regimens commonly used in the UK. The on-going TACT trial is expected to provide useful data. There are currently few data on the effectiveness of taxanes for the over-70s. Further research is required into the long-term outcomes of taxane therapy, such as whether there are any long-term adverse events that significantly impact on overall survival or quality of life and whether the increases in DFS will translate into increases in overall survival.

A systematic review and economic evaluation of statins for the prevention of coronary events

OBJECTIVES

To evaluate the clinical effectiveness and cost-effectiveness of statins for the primary and secondary prevention of cardiovascular events in adults with, or at risk of, coronary heart disease (CHD).

DATA SOURCES

Electronic databases were searched between November 2003 and April 2004.

REVIEW METHODS

A review was undertaken to identify and evaluate all literature relating to the clinical and cost effectiveness of statins in the primary and secondary prevention of CHD and cardiovascular disease (CVD) in the UK. A Markov model was developed to explore the costs and health outcomes associated with a lifetime of statin treatment using a UK NHS perspective.

RESULTS

Thirty-one randomised studies were identified that compared a statin with placebo or with another statin, and reported clinical outcomes. Meta-analysis of the available data from the placebo-controlled studies indicates that, in patients with, or at risk of, CVD, statin therapy is associated with a reduced relative risk of all cause mortality, cardiovascular mortality, CHD mortality and fatal myocardial infarction (MI), but not of fatal stroke. It is also associated with a reduced relative risk of morbidity [non-fatal stroke, non-fatal MI, transient ischaemic attack (TIA), unstable angina] and of coronary revascularisation. It is hardly possible, on the evidence available from the placebo-controlled trials, to differentiate between the clinical efficacy of atorvastatin, fluvastatin, pravastatin and simvastatin. However, there is some evidence from direct comparisons between statins to suggest that atorvastatin may be more effective than pravastatin in patients with symptomatic CHD. There is limited evidence for the effectiveness of statins in different subgroups. Statins are generally considered to be well tolerated and to have a good safety profile. This view is generally supported both by the evidence of the trials included in this review and by postmarketing surveillance data. Increases in creatine kinase and myopathy have been reported, but rhabdomyolysis and hepatotoxicity are rare. However, some patients may receive lipid-lowering therapy for as long as 50 years, and long-term safety over such a timespan remains unknown. In secondary prevention of CHD, the incremental cost-effectiveness ratios (ICERs) increase with age varying between pound 10,000 and pound 17,000 per quality adjusted life year (QALY) for ages 45 and 85 respectively. Sensitivity analyses show these results are robust. In primary prevention of CHD there is substantial variation in ICERs by age and risk. The average ICERs weighted by risk range from pound 20,000 to pound 27,500 for men and from pound 21,000 to pound 57,000 for women. The results are sensitive to the cost of statins, discount rates and the modelling time frame. In the CVD analyses, which take into account the benefits of statins on reductions in stroke and TIA events, the average ICER weighted by risk level remains below pound 20,000 at CHD risk levels down to 0.5%. Limitations of the analyses include the requirement to extrapolate well beyond the timeframe of the trial period, and to extrapolate effectiveness results from higher risk primary prevention populations to the treatment of populations at much lower risk. Consequently, the results for the lower age bands and lower risks are subject to greater uncertainty and need to be treated with caution.

CONCLUSIONS

There is evidence to suggest that statin therapy is associated with a statistically significant reduction in the risk of primary and secondary cardiovascular events. As the confidence intervals for each outcome in each prevention category overlap, it is not possible to differentiate, in terms of relative risk, between the effectiveness of statins in primary and secondary prevention. However, the absolute risk of CHD death/non-fatal MI is higher, and the number needed to treat to avoid such an event is consequently lower, in secondary than in primary prevention. The generalisability of these results is limited by the exclusion, in some studies, of patients who were hypersensitive to, intolerant of, or known to be unresponsive to, statins, or who were not adequately compliant with study medication during a placebo run-in phase. Consequently, the treatment effect may be reduced when statins are used in an unselected population. The results of the economic modelling show that statin therapy in secondary prevention is likely to be considered cost-effective. In primary prevention, the cost-effectiveness ratios are dependent on the level of CHD risk and age, but the results for the CVD analyses offer support for the more aggressive treatment recommendation issued by recent guidelines in UK. Evidence on clinical endpoints for rosuvastatin is awaited from on-going trials. The potential targeting of statins at low-risk populations is however associated with major uncertainties, particularly the likely uptake and long-term compliance to lifelong medication by asymptomatic younger patients. The targeting, assessment and monitoring of low-risk patients in primary care would be a major resource implication for the NHS. These areas require further research.

Hormonal therapies for early breast cancer: systematic review and economic evaluation

OBJECTIVES

To establish the clinical and cost-effectiveness of aromatase inhibitors (AIs) anastrozole, letrozole and exemestane compared with tamoxifen in the adjuvant treatment of early oestrogen receptor-positive breast cancer in postmenopausal women.

DATA SOURCES

Major electronic databases and three trials registers were searched from May to June 2005. Three conference abstract databases were searched in December 2005. Industry submissions.

REVIEW METHODS

Studies evaluating the clinical effectiveness of AIs against 5 years' tamoxifen treatment were included and critically appraised. The review of the health economics of AIs in early breast cancer in comparison with standard therapies included a review of existing economic evaluations of the relevant therapies, a critique of each of the economic evaluations submitted to the National Institute for Health and Clinical Excellence (NICE) by pharmaceutical manufacturers and a detailed explanation of the methodologies and results of the authors' economic model. The three treatment strategies (primary adjuvant therapy, unplanned switch therapy and extended adjuvant therapy) were considered separately within the authors' economic analysis.

RESULTS

A meta-analysis of three trials found a significant difference in overall survival when an unplanned anastrozole switching strategy was compared with 5 years' tamoxifen. Significant improvements in overall survival are yet to be demonstrated in other strategies. Compared with 5 years' tamoxifen, disease-free survival (disease recurrence or death from any cause) was significantly improved in the primary adjuvant setting with anastrozole and letrozole, and with an exemestane switching strategy. Other trials did not report this outcome. Breast cancer recurrence (censoring death as an event) was significantly improved with primary adjuvant anastrozole and letrozole, anastrozole switching, extended adjuvant anastrozole or letrozole. The AIs and tamoxifen have different side-effect profiles, with tamoxifen responsible for small but statistically significant increases in endometrial cancer and, sometimes, thromboembolic events and stroke. AIs show a trend towards increases in osteoporosis, the statistical significance of which increases with follow-up time. The absence of tamoxifen treatment also increases the risk of hypercholesterolaemia and cardiac events in postmenopausal women. There was no significant difference in overall health-related quality of life between standard treatment and either primary adjuvant anastrozole and extended adjuvant letrozole strategies. The cost-effectiveness results for AIs compared with tamoxifen in the primary adjuvant setting, are estimated to be between 21,000 pounds and 32,000 pounds per quality-adjusted life-year (QALY) based on an analysis over 35 years. There is currently no trial evidence for exemestane in this setting. The cost-effectiveness results for anastrozole and exemestane, compared with tamoxifen in the unplanned switching setting, are estimated to be 23,200 pounds and 19,200 pounds per QALY, respectively, based on an analysis over 35 years. There is currently no trial evidence for letrozole in this setting. In the extended adjuvant setting, the cost per QALY for letrozole compared with placebo is estimated to be 9800 pounds, based on an analysis over 35 years. All these results are considered to be conservative. In the base case it is assumed that the benefits of AIs over tamoxifen or placebo seen during the therapy period are gradually lost during the following 10 years. An alternative scenario, the 'benefits maintained' scenario, is tested in sensitivity analysis. Here it is assumed that following the treatment period the annual rate of recurrence in both arms is the same. This reduces the cost-effectiveness ratio by over 50%, to around 10,000-12,000 pounds, 5000 pounds and 3000 pounds in the primary adjuvant, unplanned switching and extended adjuvant setting, respectively. The limited evidence to date of benefits after the therapy period suggests that the 'benefits maintained' scenario may be realistic. The results from the economic analyses within the industry submissions are generally lower than the results from the authors' model and are close to or below 12,000 pounds in all three settings. The authors' analyses generally produce a lower estimate of QALY gain for the aromatase inhibitors, due to the more conservative assumption regarding benefits, along with differences in the utility values used in the their analysis.

CONCLUSIONS

On the basis of the current data and within their licensed indications, AIs can be considered clinically effective compared with standard tamoxifen treatment. However, their long-term effects, in terms of both benefits and harms, remain unclear. Under the conservative assumption that benefits gained by AIs during the treatment period are gradually lost over the following 10 years, the cost per QALY for AIs compared with tamoxifen is estimated to be between 21,000 pounds and 32,000 pounds in the primary adjuvant setting and around 20,000 pounds in the unplanned switch setting. The cost per QALY for AIs compared with placebo in the extended adjuvant setting is estimated to be around 10,000 pounds. Under the less conservative assumption that rates of recurrence are the same in both arms after the therapy period is complete, the incremental cost-effectiveness ratios are typically at least 50% lower, suggesting that AIs are likely to be considered cost-effective in all three settings. Understanding of the long-term treatment effects on cost-effectiveness is, however, incomplete. Data on the impact of AIs on survival are awaited from the majority of the trials to confirm whether or not the benefits seen in disease-free survival and recurrence rates are translated into overall survival benefit in the medium to long-term.

Unwanted sexual contact on campus: a comparison of women's and men's experiences

While sexual victimization continues to be a problem on college campuses, recent attention has been drawn to understanding gender differences in victimization rates and consequences. To date, these studies remain relatively few in number. The current study surveyed 651 male and female undergraduate students about unwanted sexual experiences during 1 academic year. Comparison of men and women revealed expected differences in incidence rates, with women reporting higher rates of unwanted contact. Within the subsample of reported victims, however, there was gender similarity in terms of the context of unwanted sexual experiences. Analyses also revealed the negative consequences of these experiences for both men and women and low rates of disclosure regardless of gender. Across the full sample of students surveyed, there were interesting gender differences in knowledge of campus support services, with women more likely to have attended a prevention program and to have indicated greater knowledge of rape crisis services.

Which orthodontic archwire sequence? A randomized clinical trial

The aim of this study was to compare three orthodontic archwire sequences. One hundred and fifty-four 10- to 17-year-old patients were treated in three centres and randomly allocated to one of three groups: A = 0.016-inch nickel titanium (NiTi), 0.018 x 0.025-inch NiTi, and 0.019 x 0.025-inch stainless steel (SS); B = 0.016-inch NiTi, 0.016-inch SS, 0.020-inch SS, and 0.019 x 0.025-inch SS; and C = 0.016 x 0.022-inch copper (Cu) NiTi, 0.019 x 0.025-inch CuNiTi, and 0.019 x 0.025-inch SS. At each archwire change and for each arch, the patients completed discomfort scores on a seven-point Likert scale at 4 hours, 24 hours, 3 days, and 1 week. Time in days and the number of visits taken to reach a 0.019 x 0.025-inch SS working archwires were calculated. A periapical radiograph of the upper left central incisor was taken at the start of the treatment and after placement of the 0.019 x 0.025-inch SS wire so root resorption could be assessed. There were no statistically significant differences between archwire sequences A, B, or C for patient discomfort (P > 0.05) or root resorption (P = 0.58). The number of visits required to reach the working archwire was greater for sequence B than for A (P = 0.012) but this could not be explained by the increased number of archwires used in sequence B.

Calcification inhibitors and Wnt signaling proteins are implicated in bovine artery smooth muscle cell calcification in the presence of phosphate and vitamin D sterols

Administration of active vitamin D sterols to treat secondary hyperparathyroidism in patients with chronic kidney disease receiving dialysis has been associated with elevated serum calcium and phosphorus levels, which may lead to increased risk of vascular calcification. However, calcimimetics, by binding to the parathyroid gland calcium-sensing receptors, reduce serum parathyroid hormone, calcium, phosphorus, and the calcium-phosphorus product. Using cultured bovine aorta vascular smooth muscle cells (BASMCs), an in vitro model of vascular calcification, we compared calcification levels and gene expression profiles after exposure to the phosphate source ss-glycerolphosphate (BGP), the active vitamin D sterols calcitriol and paricalcitol, the calcimimetic R-568, or BGP with the active vitamin D sterols or R-568. Cells exposed to BGP (10 mM) alone or with calcitriol or paricalcitol showed dose-dependent BASMC calcification. No change in calcification was observed in cultures exposed to BGP with R-568, consistent with the observed lack of calcium-sensing receptor expression. Microarray analysis using total cellular RNA from cultures exposed to vehicle or BGP in the absence and presence of 10(-8) M calcitriol or paricalcitol for 7 days showed that cells exposed to BGP with calcitriol or BGP with paricalcitol had virtually identical gene expression profiles, which differed from those of cells treated with BGP or vehicle alone. Several osteoblast- and chondrocyte-associated genes were modulated by BGP and vitamin D exposure. In this study, exposure of BASMCs to phosphate and active vitamin D sterols induced calcification and changes in expression of genes associated with mineralized tissue.

Donation after Cardiac Death Has a Minimal Impact on Thoracic Organ Recovery

Background

Our organ procurement organization recently developed an aggressive donation after cardiac death program. Thoracic organs are rarely recovered from Non—Heart-beating donors. Therefore, there is concern that donation after cardiac death may affect the recovery of thoracic organs from donors not allowed to progress to brain death.

Objective

To evaluate the potential impact of donation after cardiac death on the recovery of thoracic organs.

Methods

On the assumption that prolongation of care on all cases would result in a diagnosis of brain death. By retrospective chart review, all donations after cardiac death were evaluated for thoracic organ potential using the same standards that were used to evaluate brain-dead donors.

Results

During the study period there were 34 of 44 (77%) Non—Heart-beating donors qualified to donate abdominal organs only. Ten of 44 Non—Heart-beating donors (24%) qualified to potentially donate thoracic organs; the families of 4 of 10 of these donors insisted on the immediate withdrawal of life support, leaving only 6 donors with thoracic organ potential. All 6 of these donors qualified as potential heart donors and 3 as potential lung donors.

Conclusions

A total of 97 organs were recovered and successfully transplanted from 44 Non—Heart-beating donors. If all the donors who qualified to donate thoracic organs progressed to brain death and if their thoracic organs were transplantable, then 6 additional hearts and 3 pairs of lungs may have been recovered. These data demonstrate that an aggressive donation after cardiac death program contributes significantly to the organ donor pool, with a minimal impact on potential thoracic organ recovery.

Dominant influence of an HLA-B27 restricted CD8+ T cell response in mediating HCV clearance and evolution

Virus-specific CD8+ T cell responses play an important role in the natural course of infection; however, the impact of certain CD8+ T cell responses in determining clinical outcome has not been fully defined. A well-defined cohort of women inoculated with HCV from a single source showed that HLA-B27 has a strong association with spontaneous clearance. The immunological basis for this association is unknown. However, the finding is especially significant because HLA-B27 has also been shown to have a protective role in HIV infection. We report the identification of an HLA-B27 restricted hepatitis C virus (HCV)-specific CD8+ T cell epitope that is recognized in the majority of recovered HLA-B27 positive women. In chronically HCV-infected individuals, analysis of the corresponding viral sequence showed a strong association between sequence variations within this epitope and expression of HLA-B27, indicating allele-specific selection pressure at the population level. Functional analysis in 3 chronically HCV-infected patients showed that the emerging variant viral epitopes represent escape mutations. In conclusion, our results suggest a dominant role of HLA-B27 in mediating spontaneous viral clearance as well as viral evolution in HCV infection and mechanistically link both associations to a dominant novel CD8+ T cell epitope. These results support the central role of virus-specific CD8+ T cells and the genetically determined restriction of the virus-specific T cell repertoire in HCV infection.

Do antiviral CD8+ T cells select hepatitis C virus escape mutants? Analysis in diverse epitopes targeted by human intrahepatic CD8+ T lymphocytes

Hepatitis C virus (HCV) is a variable RNA virus that can readily establish persistent infection. Cellular immune responses are important in the early control of the virus. Evidence from animal models suggests that mutation in epitopes recognized by CD8+ T lymphocytes may play an important role in the establishment of persistence but in human persistent infection, equivalent evidence is lacking. We investigated this by analysing a unique resource: viruses from a set of chronically HCV-infected individuals in whom the CD8+ T-cell responses in liver had previously been accurately mapped. Virus was sequenced in seven individuals at 10 epitopes restricted by 10 human leucocyte antigen (HLA) molecules. Two main patterns emerged: in the majority of epitopes sequenced, no variation was seen. In three epitopes, mutations were identified which were compatible with immune escape as assessed using phylogenetic and/or functional studies. These data suggest that - even where specific intrahepatic T cells are detectable - many epitopes do not undergo mutation in chronic human infection. On the contrary, virus may escape from intrahepatic CD8+ T-cell responses in a 'patchy' manner in certain specific epitopes. Furthermore, longitudinal studies to identify the differences between 'selecting' and 'nonselecting' intrahepatic CD8+ T-cell responses are needed in HCV infection.

Randomised controlled trial of non-invasive ventilation (NIV) for nocturnal hypoventilation in neuromuscular and chest wall disease patients with daytime normocapnia

BACKGROUND

Long term non-invasive ventilation (NIV) reduces morbidity and mortality in patients with neuromuscular and chest wall disease with hypercapnic ventilatory failure, but preventive use has not produced benefit in normocapnic patients with Duchenne muscular dystrophy. Individuals with nocturnal hypercapnia but daytime normocapnia were randomised to a control group or nocturnal NIV to examine whether nocturnal hypoventilation is a valid indication for NIV.

METHODS

Forty eight patients with congenital neuromuscular or chest wall disease aged 7-51 years and vital capacity<50% predicted underwent overnight respiratory monitoring. Twenty six with daytime normocapnia and nocturnal hypercapnia were randomised to either nocturnal NIV or to a control group without ventilatory support. NIV was started in the control group if patients fulfilled preset safety criteria.

RESULTS

Peak nocturnal transcutaneous carbon dioxide tension (Tcco2) did not differ between the groups, but the mean (SD) percentage of the night during which Tcco2 was >6.5 kPa decreased in the NIV group (-57.7 (26.1)%) but not in controls (-11.75 (46.1)%; p=0.049, 95% CI -91.5 to -0.35). Mean (SD) arterial oxygen saturation increased in the NIV group (+2.97 (2.57)%) but not in controls (-1.12 (2.02)%; p=0.024, 95% CI 0.69 to 7.5). Nine of the 10 controls failed non-intervention by fulfilling criteria to initiate NIV after a mean (SD) of 8.3 (7.3) months.

CONCLUSION

Patients with neuromuscular disease with nocturnal hypoventilation are likely to deteriorate with the development of daytime hypercapnia and/or progressive symptoms within 2 years and may benefit from the introduction of nocturnal NIV before daytime hypercapnia ensues.

Heat transfer and the energetic cost of singing by canaries Serinus canaria

Sexually selected displays, such as male passerine bird song, are predicted to be costly. However, most measurements calculated the rate of oxygen consumption during singing using respirometry have shown that bird song has a low energetic cost. Since birds are reluctant to sing when enclosed inside a respirometry chamber, the energetic cost of singing could differ from that under more normal circumstances. We used heat transfer modelling, based on thermal images, to estimate the energetic cost of singing by canaries (Serinus canaria) that were not enclosed in respirometry chambers. Metabolic rate calculated from heat transfer modelling was 0.70 +/- 0.02 W (N = 10 birds) during singing, which was 14+/-5% greater than during standing (0.62 +/- 0.02 W). The energetic cost of singing did not differ significantly from that measured previously using respirometry when we took into account that birds sang for a greater proportion of the time during the current experiments. These conclusions were not sensitive to potential errors in the heat transfer model. Heat transfer modelling would be especially useful to obtain measurements of the energetic cost of activities that animals do not perform readily inside respirometry chambers, such as singing in birds.

Maxillary incisor palatal erosion: no correlation with dietary variables?

The objectives of the study were to examine a relationship between tooth erosion affecting the palatal aspects of permanent maxillary central incisors with dietary, behavioral and medical variables. The methods included, 251 schoolchildren aged 11 to 13 years were recruited to participate. Each subject had dental impressions of the palatal aspects of both upper central incisors recorded at baseline, 9 and 18 months intervals. From these, electroconductive replicas were fabricated, mapped and compared using a surface matching technique. At the end of the study all participants underwent a structured interview that sought to assay the level of potential erosive dietary, behavioral and medical risk factors. Correlation analyses of the responses given in the final structured interview with the degrees of palatal tooth substance loss (both previous and measured) were under taken. The results showed: (1) The degree of previous erosion did not predict the level of measured ongoing erosion. (2) Brushing the teeth more frequently with fluoridated toothpaste correlated significantly with lower levels of ongoing erosion (P = 0 011). It was concluded that: (1) Evidence of previous palatal erosion did not predict future erosion. (2) The application of topical fluoride as a by-product of tooth brushing may provide an element of protection against palatal erosion. (3) In view of the lack of correlation between exposure to potential risk factors and the level of ongoing palatal tooth surface loss in this study, other factors (such as an individual's susceptibility and salivary buffering power) may well be more important predictors. The clinical relevance included: Preventive advice to patients with dental erosion should not only include the use of topical fluoride, in the form of toothpaste, but recognize individual susceptibility to this condition.

Metabolic power of European starlings Sturnus vulgaris during flight in a wind tunnel, estimated from heat transfer modelling, doubly labelled water and mask respirometry

It is technically demanding to measure the energetic cost of animal flight. Each of the previously available techniques has some disadvantage as well advantages. We compared measurements of the energetic cost of flight in a wind tunnel by four European starlings Sturnus vulgaris made using three independent techniques: heat transfer modelling, doubly labelled water (DLW) and mask respirometry. We based our heat transfer model on thermal images of the surface temperature of the birds and air flow past the body and wings calculated from wing beat kinematics. Metabolic power was not sensitive to uncertainty in the value of efficiency when estimated from heat transfer modelling. A change in the assumed value of whole animal efficiency from 0.19 to 0.07 (the range of estimates in previous studies) only altered metabolic power predicted from heat transfer modelling by 13%. The same change in the assumed value of efficiency would cause a 2.7-fold change in metabolic power if it were predicted from mechanical power. Metabolic power did not differ significantly between measurements made using the three techniques when we assumed an efficiency in the range 0.11-0.19, although the DLW results appeared to form a U-shaped power-speed curve while the heat transfer model and respirometry results increased linearly with speed. This is the first time that techniques for determining metabolic power have been compared using data from the same birds flying under the same conditions. Our data provide reassurance that all the techniques produce similar results and suggest that heat transfer modelling may be a useful method for estimating metabolic rate.

Incidence and prevalence of lymphedema in patients following burn injury: a five-year retrospective and three-month prospective study

BACKGROUND

Burn injuries and the disease process of lymphedema are complex medical conditions involving the integument. The possibility of a relationship between burn injury and the development of lymphedema was studied.

METHODS AND RESULTS

The incidence of lymphedema was explored by conducting a 5-year retrospective chart review on edema related ICD-9 codes. The prevalence of lymphedema was assessed in a prospective study of patients in a burn clinic. The techniques used to diagnose lymphedema were utilized on all patients presenting to clinic with extremity edema. The prospective analysis reviewed the lymphedema tests and measures and burn characteristics to determine those that were appropriate to diagnose or predict the risk of lymphedema in a burn patient. A 6-month follow-up study was also conducted to re-examine subjects initially diagnosed with lymphedema.

CONCLUSIONS

The retrospective review did not reveal significant findings to determine incidence of lymphedema following burn injury. The prospective study identified eight patients with a clinical diagnosis of lymphedema. Two of the eight subjects had a previous diagnosis of lymphedema prior to the burn injury. The six remaining subjects represent a prevalence of 1.0%. Specific tests and measures, Stemmer Sign, deepening of skin folds, and the lack of venous alterations, were found to be appropriate measures to diagnose lymphedema in the burn patient population. Specific burn characteristics, circumferential extremity involvement, and fascial excision, also identified burn patients who may be at risk for developing lymphedema. Lastly, the results of the 6-month re-evaluation confirmed the original diagnoses.

Fitts' law as a function of system dynamics and target uncertainty

Fins' law was found to hold for discrete movements executed by subjects controlling the velocity of a cursor with a control stick The slope of movement time versus index of difficulty was approximately twice as large as for a comparable position control system. Target uncertainty also increased the slope of total time versus index of difficulty, and this effect is interpreted in terms of adaptive tuning of the human movement system.

A novel approach to evaluating the reproducibility of a replication technique for the manufacture of electroconductive replicas for use in quantitative clinical dental wear studies

The assessment of the progression of tooth surface loss has until recently been limited to either the application of subjective ranking scales or visual comparison of sequential study casts. The development of quantitative measuring techniques offers the potential of greater accuracy and sensitivity. As direct intra-oral measurement is problematical such approaches often utilize impressions of the teeth, recorded at different epochs, to construct replicas for mapping and comparison. This in vitro investigation sought to determine the reproducibility of such an approach taking into account the total process chain. Two inlay cavities (one large, one small) were prepared in the palatal aspect of a plastic maxillary central incisor and restored with two flush fitting inlays. A series of impressions of this tooth were recorded, using a special tray and an addition cured light bodied silicone impression material (President, Coltene, Switzerland), with (a) both inlays in (b) both inlays out (c) large inlay out and small inlay in (d) large inlay in and small inlay out - a total of 16 impressions. Electroconductive replicas were fabricated from these and mapped using a computer controlled probe. Each series simulated wear of the tooth. A surface matching and difference detection algorithm was then used to compare each series of replicas and calculate the proportion of the surface undergoing simulated wear by a direct comparison of (a) matched to (b) or, indirectly as the summation of the results of matches of (a) with (c) and (a) with (d). The mean proportion of the surface with wear calculated directly was 26.6% (s.d.=0.6) and indirectly 26.1% (s.d. = 0.5). A one-way anova revealed no significant difference (P > 0.05). It is concluded that determining wear by this method is highly reproducible.

Rationalization of quantitative tooth surface loss data for epidemiological research

Recent UK National Surveys have revealed a high prevalence of tooth surface loss (TSL) because of erosion in Children and Adolescents. Although digital surface mapping and surface matching techniques may be used to quantify its progression with time, reporting TSL of individuals as a function of either mean depth loss or volume loss, this can be inadequate when transferred for epidemiological analysis. For example, a tooth displaying multiple regions of depth loss may deserve to be distinguished from a tooth with a single localised area of erosion, although the total volume change may be the same. A potential solution, explored here, is to use both the quantitative wear data and colour coded surface representation plots generated by such methods to arrive at a single categorical wear score [1 (< or = 5% of surface exhibits TSL) to 5 (> or = 51% of surface exhibits TSL)]. Two examiners independently categorized, on two separate occasions, the TSL of 53 maxillary incisors (26 subjects observed at baseline and 9 months). Their performance was assessed for intra- and inter-examiner agreement by; (i) calculating the percentage of agreement, (ii) a Wilcoxon matched-pairs signed rank test. Thereafter, in cases of disagreement a consensus score was allocated and a regression analysis of this versus the numerically derived percentage of the surface that had undergone change was carried out. Intra- and inter-examiner agreement was 100 and 88.7% respectively and for the inter-examiner comparison P = 0.0456. The categorical scores and the quantitative wear data correlated linearly (R = 0.82). It is concluded that the method used to rationalize the quantitative TSL data is both reproducible and reflects the quantitative data. Its use should be helpful in epidemiological TSL studies but continued vigilance is required in cases of examiner disagreement.

Clinical and cost-effectiveness of capecitabine and tegafur with uracil for the treatment of metastatic colorectal cancer: systematic review and economic evaluation

OBJECTIVES

To evaluate the clinical and cost-effectiveness of capecitabine and tegafur with uracil (UFT/LV) as first-line treatments for patients with metastatic colorectal cancer, as compared with 5-fluorouracil/folinic acid (5-FU/FA) regimens.

DATA SOURCES

Electronic databases, reference lists of relevant articles and sponsor submissions were also consulted.

REVIEW METHODS

Systematic searches, selection against criteria and quality assessment were performed to obtain data from relevant studies. Costs were estimated through resource-use data taken from the published trials and the unpublished sponsor submissions. Unit costs were taken from published sources, where available. An economic evaluation was undertaken to compare the cost-effectiveness of capecitabine and UFT/LV with three intravenous 5-FU/LV regimens widely used in the UK: the Mayo, the modified de Gramont regimen and the inpatient de Gramont regimens.

RESULTS

The evidence suggests that treatment with capecitabine improves overall response rates and has an improved adverse effect profile in comparison with 5-FU/LV treatment with the Mayo regimen, with the exception of hand-foot syndrome. Time to disease progression or death after treatment with UFT/LV in one study appears to be shorter than after treatment with 5-FU/LV with the Mayo regimen, although it also had an improved adverse effect profile. Neither capecitabine nor UFT/LV appeared to improve health-related quality of life. Little information on patient preference was available for UFT/LV, but there was indicated a strong preference for this over 5-FU/LV. The total cost of capecitabine and UFT/LV treatments were estimated at 2111 pounds and 3375 pounds, respectively, compared with the total treatment cost for the Mayo regimen of 3579 pounds. Cost estimates were also presented for the modified de Gramont and inpatient de Gramont regimens. These were 3684 pounds and 6155 pounds, respectively. No survival advantage was shown in the RCTs of the oral drugs against the Mayo regimen. Cost savings of capecitabine and UFT/LV over the Mayo regimen were estimated to be 1461 pounds and 209 pounds, respectively. Drug acquisition costs were higher for the oral therapies than for the Mayo regimen, but were offset by lower administration costs. Adverse event treatment costs were similar across the three regimens. It was inferred that there was no survival difference between the oral drugs and the de Gramont regimens. Cost savings of capecitabine and UFT/LV over the modified de Gramont regimen were estimated to be 1353 pounds and 101 pounds, respectively, and over the inpatient de Gramont regimen were estimated to be 4123 pounds and 2870 pounds, respectively.

CONCLUSIONS

The results show that there are cost savings associated with the use of oral therapies. No survival difference has been proven between the oral drugs and the Mayo regimen. In addition, no evidence of a survival difference between the Mayo regimen and the de Gramont regimens has been identified. However, improved progression-free survival and an improved adverse event profile have been shown for the de Gramont regimen over the Mayo regimen. Further research is recommended into the following areas: quality of life data should be included in trials of colorectal cancer treatments; the place of effective oral treatments in the treatment of colorectal cancer, the safety mechanisms needed to ensure compliance and the monitoring of adverse effects; the optimum duration of treatment; the measurement of patient preference; and a phase III comparative trial of capecitabine and UFT/LV versus modified de Gramont treatment to determine whether there was any survival advantage and to collate the necessary economic data.

Cost-utility analysis of imatinib mesilate for the treatment of advanced stage chronic myeloid leukaemia

Imatinib mesilate (Glivec), Novartis Pharmaceuticals) is a novel therapy for the treatment of chronic myeloid leukaemia (CML). We evaluated the cost-effectiveness of imatinib (600 mg daily) when used for the treatment of patients in advanced stages of CML (accelerated phase and blast crisis) against conventional therapies of combination chemotherapy (DAT) and palliative care in hospital or at home. A Markov model simulated the transitions of hypothetical patient cohorts and outcomes were modelled for 5 years from the start of treatment. Costs were estimated from the perspective of the UK National Health Service. Over 5 years, a patient in accelerated phase will, on average, accrue an additional 2.09 QALYs with imatinib compared to conventional therapies, while patients in blast crisis will accrue an additional 0.58 quality-adjusted life-years (QALYs) with imatinib compared to conventional therapies. The costs per additional QALY gained from treatment with imatinib compared with conventional therapies were pound 29344 (accelerated phase) and pound 42239 (blast crisis). The results were particularly sensitive to the price of imatinib, improvements in quality of life, and the duration of haematological responses. We conclude that treatment of CML with imatinib confers considerably greater survival and quality of life than conventional treatments but at a cost.

Assessment of a procedure for detecting minute levels of tooth erosion

Over a period of some years, the components of a system for discerning erosion on children's teeth have been progressively developed, for use in an extensive project seeking correlations between erosion and various perceived risk factors. The aim was the detection of minute levels of erosion, based on mappings of the palatal surfaces of the maxillary central incisors in children. Significant challenges were encountered, the primary problem being the impracticality of placing control marks that would aid the realignment of successive measurements. The paper describes the erosion detection system and initial experiences based on the results of the first 100 subjects measured after 9 months. The procedures detected the occurrence of erosion of 50 microm magnitude on about one-quarter of the teeth over the 9 month period, at a precision estimated to be +/- 15 microm. The occurrence of some anomalous incidents prevented the procedure from being fully automatic, and it necessitated human examination of a graphical diagram derived from the surface matching program, but it was nevertheless superior to current practices of examining impressions or replicas entirely by eye.

Slower rise of exhaled breath temperature in chronic obstructive pulmonary disease

In chronic obstructive pulmonary disease (COPD) there is decreased vascularity of the bronchi and inflammation of the airways that may have opposite effects on the regulation of heat loss. Exhaled air temperature increase (delta(e) T) was measured in 23 patients with moderate COPD (18 male, mean age +/- SEM 70 +/- 1 yrs; forced expiratory volume in one second (FEV1) 45 +/- 3%, FEV1/forced vital capacity 54 +/- 4%) and 16 normal volunteers (64 +/- 4 yr) and compared to exhaled nitric oxide (eNO) and inflammatory cells in induced sputum as a marker of airway inflammation. Delta(e) T was measured during a flow- and pressure-controlled single exhalation with a fast-response thermometer. delta(e) T was reduced in patients with COPD (1.86 +/- 0.15 delta C x s(-1)) compared to normal subjects (4.00 +/- 0.26 delta C x s(-1)). There was no difference in delta(e) T between patients treated with inhaled steroids and those who were steroid naïve. Delta(e) T was correlated with eNO (r=0.60) but not with sputum neutrophilia. In COPD patients, delta(e) T was increased (2.26 +/- 0.16 delta C x s(-1)) after the inhalation of 200 microg of albuterol, which is a known vasodilator, indicating that delta(e) T and bronchial blood flow may be correlated. Exhaled temperature increase is reduced in chronic obstructive pulmonary disease patients and is increased by the inhalation of vasodilators and therefore may be related to changes of bronchial blood flow and tissue remodelling.

Viral escape and T cell exhaustion in hepatitis C virus infection analysed using Class I peptide tetramers

Hepatitis C virus (HCV) has infected over 170 million people world wide, and in the majority sets up a chronic infection associated with hepatic inflammation. How it evades host immunity, particularly CD8+ T cells (CTL) is unclear, but two major factors are likely to operate, viral escape mutation and T cell exhaustion. We have investigated the role of CTL in control of infection during acute disease using Class I peptide tetramers. Although the immune response is quite diverse and numerous epitopes can be targeted, we observe that, especially during acute disease, one epitope (NS3 1073-81) is commonly recognised in HLA-A2 positive individuals. However, the levels of response to this epitope (and others) are very much lower if persistence is established. We examined in detail whether the cause of this low level of reactivity is due to mutation within the epitope. We find that, in fact this epitope is highly conserved during chronic infection, at a clonal level, between individuals, and over time. Thus, although variation within the epitope does occur, lack of reactivity in peripheral blood against this epitope in chronic disease, and loss of control of virus cannot be explained entirely by viral escape. Escape through mutation probably does play an important role in persistence of HCV, but we also discuss other mechanisms which lead to attenuation of T cell responses which may be important in determining the outcome.

Heart rate and the rate of oxygen consumption of flying and walking barnacle geese (Branta leucopsis) and bar-headed geese (Anser indicus)

We tested the hypotheses that the relationship between heart rate(fH) and the rate of oxygen consumption(V̇O2) differs between walking and flying in geese and that fH and V̇O2 have a U-shaped relationship with flight speed. We trained barnacle geese Branta leucopsis (mean mass 2.1 kg) and bar-headed geese Anser indicus(mean mass 2.6 kg) to walk inside a respirometer on a treadmill and to fly in a wind tunnel with a respirometry mask at a range of speeds. We measured fH and V̇O2simultaneously during walking on the treadmill in five individuals of each species and in one bar-headed goose and four barnacle geese during flight in the wind tunnel. The relationships between fH and V̇O2 were significantly different between flying and walking. V̇O2 was higher,and the increment in V̇O2 for a given increase in fH was greater, for flying than for walking geese. The relationship between fH and V̇O2 of free-living barnacle geese during their natural migratory flights must differ from that measured in the wind tunnel, since the fH of wild migratory birds corresponds to values of V̇O2 that are unrealistically low when using the calibration relationship for our captive birds. Neither fH nor V̇O2 varied with flight velocity across the range of speeds over which the geese would fly sustainably.

The energetics of barnacle geese (Branta leucopsis) flying in captive and wild conditions

Experimental data on the relationship between mean heart rate (f(H)) and mean rate of oxygen consumption (VO(2)) of captive barnacle geese during flights in a wind tunnel are assessed in terms of their capacity to predict the typical VO(2) of wild barnacle geese, based on the recordings of their f(H), while undertaking autumn migratory flights between Spitsbergen (78 degrees N) and Caerlaverock, Scotland (55 degrees N). A significant linear relationship has been demonstrated between the f(H) and simultaneously recorded VO(2) of a single barnacle goose (B-B) flying in the wind tunnel (VO(2)=1.42 f(H)-304, r(2)=0.82, P<0.001, N=12 flights). Data recorded from three additional geese (N=4 flights), lay within the 95% prediction intervals of the relationship for goose B-B. When these geese (mean body mass=2.06 kg, n=4) were flown in the wind tunnel (WT) without the mask, they had a mean f(H) of 451+/-23 beats min(-1), yielding an estimate for VO(2) of 336+/-33 ml min(-1). However, f(H) has also been recorded from wild barnacle geese (mean migratory f(H) of 253 beats min(-1)), and substitution of this value into the above calibration equation results in an unrealistically low value for mean migratory VO(2) of only 55 ml min(-1). Various factors, such as differences in heart mass, selective tissue perfusion, environmental temperature and flock formation, which might account for some of the difference in f(H) between the captive and wild geese are discussed. Comparison with other WT studies shows that inter-species minimum mass-specific VO(2) declines with increasing body mass (M(b); range 0.035-2.8 kg) as 173 M(b)(-0.224), r(2)=0.848.

Evaluation of the accuracy and reproducibility of a replication technique for the manufacture of electroconductive replicas for use in quantitative clinical dental wear studies

This work sought to evaluate the accuracy and reproducibility of a replication process that formed electroconductive replicas from addition cured silicone impressions for the purposes of monitoring tooth surface loss. Replicas were constructed by painting the surface of impressions with one of three high silver content electroconductive paints [Electrocure (EC), RS Silver Paint (SP) and Electrolube (EB)] and, once dry, backing this up with a cyanoacrylate based gel material (Zapit) and die stone. For each paint an impression was recorded of a gauge block of known step height (1270 microm) and five impressions of the palatal surface of a laboratory standard maxillary central incisor were also recorded. All impressions were taken using an addition cured silicone impression material (President). The resultant electroconductive replicas were mapped using a computer controlled probe. This data was analysed to determine both the replica's step height and, using surface matching techniques, the reproducibility of the replication process. The mean step heights recorded were; EC=1268.43 (s.d.=12.09), SP=1267.09 (s.d. 1.77) and EB 1299.58 (s.d. 14.47). Both EC and SP recorded the step height to within 3 microm. In the repeat replication of the palatal surface of an upper central incisor SP maintained a greater constancy of surface topography (99.6%) that was statistically superior to both EC (P < 0.05) and EB (P < 0.01). The SP was therefore the preferred paint for this technique. Bearing this in mind the replication technique was both accurate and reproducible but vigilance, as to the selection of paint for the process, should be exercised so as not to affect the good accuracy and reproducibility of the technique.