Individualised Estimation of Quality-adjusted Survival Benefit and Cost-effectiveness of Proton Beam Therapy in Intermediate-stage Hodgkin Lymphoma

AIMS

Radiotherapy for Hodgkin lymphoma leads to the irradiation of organs at risk (OAR), which may confer excess risks of late effects. Comparative dosimetry studies show that proton beam therapy (PBT) may reduce OAR irradiation compared with photon radiotherapy, but PBT is more expensive and treatment capacity is limited. The purpose of this study is to inform the appropriateness of PBT for intermediate-stage Hodgkin lymphoma (ISHL).

MATERIALS AND METHODS

A microsimulation model simulating the course of ISHL, background mortality and late effects was used to estimate comparative quality-adjusted life years (QALYs) lived and healthcare costs after consolidative pencil beam scanning PBT or volumetric modulated arc therapy (VMAT), both in deep-inspiration breath-hold. Outcomes were compared for 606 illustrative patients covering a spectrum of clinical presentations, varying by two age strata (20 and 40 years), both sexes, three smoking statuses (never, former and current) and 61 pairs of OAR radiation doses from a comparative planning study. Both undiscounted and discounted outcomes at 3.5% yearly discount were estimated. The maximum excess cost of PBT that might be considered cost-effective by the UK's National Institute for Health and Care Excellence was calculated.

RESULTS

OAR doses, smoking status and discount rate had large impacts on QALYs gained with PBT. Current smokers benefited the most, averaging 0.605 undiscounted QALYs (range -0.341 to 2.171) and 0.146 discounted QALYs (range -0.067 to 0.686), whereas never smokers benefited the least, averaging 0.074 undiscounted QALYs (range -0.196 to 0.491) and 0.017 discounted QALYs (range -0.030 to 0.086). For the gain in discounted QALYs to be considered cost-effective, PBT would have to cost at most £4812 more than VMAT for current smokers and £645 more for never smokers. This is below preliminary National Health Service cost estimates of PBT over photon radiotherapy.

CONCLUSION

In a UK setting, PBT for ISHL may not be considered cost-effective. However, the degree of unquantifiable uncertainty is substantial.

Modelling incremental benefits on complications rates when targeting lower HbA1c levels in people with Type 2 diabetes and cardiovascular disease

AIM

Glucose-lowering interventions in Type 2 diabetes mellitus have demonstrated reductions in microvascular complications and modest reductions in macrovascular complications. However, the degree to which targeting different HbA_1c reductions might reduce risk is unclear.

METHODS

Participant-level data for Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS) participants with established cardiovascular disease were used in a Type 2 diabetes-specific simulation model to quantify the likely impact of different HbA_1c decrements on complication rates. Ten-year micro- and macrovascular rates were estimated with HbA_1c levels fixed at 86, 75, 64, 53 and 42 mmol/mol (10%, 9%, 8%, 7% and 6%) while holding other risk factors constant at their baseline levels. Cumulative relative risk reductions for each outcome were derived for each HbA_1c decrement.

RESULTS

Of 5717 participants studied, 72.0% were men and 74.2% White European, with a mean (sd) age of 66.2 (7.9) years, systolic blood pressure 134 (16.9) mmHg, LDL-cholesterol 2.3 (0.9) mmol/l, HDL-cholesterol 1.13 (0.3) mmol/l and median Type 2 diabetes duration 9.6 (5.1-15.6) years. Ten-year cumulative relative risk reductions for modelled HbA_1c values of 75, 64, 53 and 42 mmol/mol, relative to 86 mmol/mol, were 4.6%, 9.3%, 15.1% and 20.2% for myocardial infarction; 6.0%, 12.8%, 19.6% and 25.8% for stroke; 14.4%, 26.6%, 37.1% and 46.4% for diabetes-related ulcer; 21.5%, 39.0%, 52.3% and 63.1% for amputation; and 13.6%, 25.4%, 36.0% and 44.7 for single-eye blindness.

CONCLUSIONS

These simulated complication rates might help inform the degree to which complications might be reduced by targeting particular HbA_1c reductions in Type 2 diabetes.

Cost-effectiveness of a pragmatic structured education intervention for the prevention of type 2 diabetes: economic evaluation of data from the Let's Prevent Diabetes cluster-randomised controlled trial

OBJECTIVES

Prevention of type 2 diabetes mellitus (TD2M) is a priority for healthcare systems. We estimated the cost-effectiveness compared with standard care of a structured education programme (Let's Prevent) targeting lifestyle and behaviour change to prevent progression to T2DM in people with prediabetes.

DESIGN

Cost-effectiveness analysis alongside randomised controlled trial.

SETTING

44 general practices in Leicestershire, England.

PARTICIPANTS

880 participants with prediabetes randomised to receive either standard care or a 6-hour group structured education programme with follow-up sessions in a primary care setting.

MAIN OUTCOME MEASURE

Incremental cost utility from the UK National Health Service (NHS) perspective. Quality of life and resource use measured from baseline and during the 36 months follow-up using the EuroQoL EQ-5D and 15D instruments and an economic questionnaire. Outcomes measured using quality-adjusted life years (QALYs) and healthcare costs calculated in 2012-2013 prices.

RESULTS

After accounting for clustering and missing data, the intervention group was found to have a net gain of 0.046 (95% CI -0.0171 to 0.109) QALYs over 3 years, adjusted for baseline utility, at an additional cost of £168 (95% CI -395 to 732) per patient compared with the standard care group. The incremental cost-effectiveness ratio is £3643/QALY with an 86% probability of being cost-effective at a willingness to pay threshold of £20 000/QALY.

CONCLUSIONS

The education programme had higher costs and higher quality of life compared with the standard care group. The Let's Prevent programme is very likely to be cost-effective at a willingness to pay threshold of £20 000/QALY gained.

TRIAL REGISTRATION NUMBER

ISRCTN80605705.

The impact of social isolation on delayed hospital discharges of older hip fracture patients and associated costs

Delayed discharges represent an inefficient use of acute hospital beds. Social isolation and referral to a public-funded rehabilitation unit were significant predictors of delayed discharges while admission from an institution was a protective factor for older hip fracture patients. Preventing delays could save between 11.2 and 30.7 % of total hospital costs for this patient group.

INTRODUCTION

Delayed discharges of older patients from acute care hospitals are a major challenge for administrative, humanitarian, and economic reasons. At the same time, older people are particularly vulnerable to social isolation which has a detrimental effect on their health and well-being with cost implications for health and social care services. The purpose of the present study was to determine the impact and costs of social isolation on delayed hospital discharge.

METHODS

A prospective study of 278 consecutive patients aged 75 or older with hip fracture admitted, as an emergency, to the Orthopaedics Department of Hospital Universitário de Santa Maria, Portugal, was conducted. A logistic regression model was used to examine the impact of relevant covariates on delayed discharges, and a negative binomial regression model was used to examine the main drivers of days of delayed discharges. Costs of delayed discharges were estimated using unit costs from national databases.

RESULTS

Mean age at admission was 85.5 years and mean length of stay was 13.1 days per patient. Sixty-two (22.3 %) patients had delayed discharges, resulting in 419 bed days lost (11.5 % of the total length of stay). Being isolated or at a high risk of social isolation, measured with the Lubben social network scale, was significantly associated with delayed discharges (odds ratio (OR) 3.5) as was being referred to a public-funded rehabilitation unit (OR 7.6). These two variables also increased the number of days of delayed discharges (2.6 and 4.9 extra days, respectively, holding all else constant). Patients who were admitted from an institution were less likely to have delayed discharges (OR 0.2) with 5.5 fewer days of delay. Total costs of delayed discharges were between 11.2 and 30.7 % of total costs (€2352 and €9317 per patient with delayed discharge) conditional on whether waiting costs for placement in public-funded rehabilitation unit were included.

CONCLUSION

High risk of social isolation, social isolation and referral to public-funded rehabilitation units increase delays in patients' discharges from acute care hospitals.

Impact of hip fracture on hospital care costs: a population-based study

Using a large cohort of hip fracture patients, we estimated hospital costs to be £14,163 and £2139 in the first and second year following fracture, respectively. Second hip and non-hip fractures were major cost drivers. There is a strong economic incentive to identify cost-effective approaches for hip fracture prevention.

INTRODUCTION

The purpose of this study was to estimate hospital costs of hip fracture up to 2 years post-fracture and compare costs before and after the index fracture.

METHODS

A cohort of patients aged over 60 years admitted with a hip fracture in a UK region between 2003 and 2013 were identified from hospital records and followed until death or administrative censoring. All hospital records were valued using 2012/2013 unit costs, and non-parametric censoring methods were used to adjust for censoring when estimating average annual costs. A generalised linear model examined the main predictors of hospital costs.

RESULTS

A cohort of 33,152 patients with a hip fracture was identified (mean age 83 years (SD 8.2). The mean censor-adjusted 1- and 2-year hospital costs after index hip fracture were £14,163 (95 % confidence interval (CI) £14,008 to £14,317) and £16,302 (95 % CI £16,097 to £16,515), respectively. Index admission accounted for 61 % (£8613; 95 % CI £8565 to £8661) of total 1-year hospital costs which were £10,964 higher compared to the year pre-event (p < 0.001). The main predictors of 1-year hospital costs were second hip fracture, other non-hip fragility fractures requiring hospitalisation and hip fracture-related complications. Total UK annual hospital costs associated with incident hip fractures were estimated at £1.1 billion.

CONCLUSIONS

Hospital costs following hip fracture are high and mostly occur in the first year after the index hip fracture. Experiencing a second hip fracture after the index fracture accounted for much of the increase in costs. There is a strong economic incentive to prioritise research funds towards identifying the best approaches to prevent both index and subsequent hip fractures.

Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit

Background

Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain.

Methods

We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using ¹⁴C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to ¹⁴C-sucrose and radioactive albumin.

Results

In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with ¹⁴C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and ¹⁴C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.

Conclusions

The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is to be dependent on COX but not on oxidative stress. Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

UKPDS outcomes model 2: a new version of a model to simulate lifetime health outcomes of patients with type 2 diabetes mellitus using data from the 30 year United Kingdom Prospective Diabetes Study: UKPDS 82

AIMS/HYPOTHESIS

The aim of this project was to build a new version of the United Kingdom Prospective Diabetes Study (UKPDS) Outcomes Model (UKPDS-OM1), a patient-level simulation tool for predicting lifetime health outcomes of people with type 2 diabetes mellitus.

METHODS

Data from 5,102 UKPDS patients from the 20 year trial and the 4,031 survivors entering the 10 year post-trial monitoring period were used to derive parametric proportional hazards models predicting absolute risk of diabetes complications and death. We re-estimated the seven original event equations and estimated new equations for diabetic ulcer and some second events. The additional data permitted inclusion of new risk factor predictors such as estimated GFR. We also developed four new equations for all-cause mortality. Internal validation of model predictions of cumulative incidence of all events and death was carried out and a contemporary patient-level dataset was used to compare 10 year predictions from the original and the new models.

RESULTS

Model equations were based on a median 17.6 years of follow-up and up to 89,760 patient-years of data, providing double the number of events, greater precision and a larger number of significant covariates. The new model, UKPDS-OM2, is internally valid over 25 years and predicts event rates for complications, which are lower than those from the existing model.

CONCLUSIONS/INTERPRETATION

The new UKPDS-OM2 has significant advantages over the existing model, as it captures more outcomes, is based on longer follow-up data, and more comprehensively captures the progression of diabetes. Its use will permit detailed and reliable lifetime simulations of key health outcomes in people with type 2 diabetes mellitus.

UK research expenditure on dementia, heart disease, stroke and cancer: are levels of spending related to disease burden?

BACKGROUND AND PURPOSE

A UK government review recommended that the impact of disease on the population and economy should be assessed to inform health research priorities. This study aims to quantify UK governmental and charity research funding for dementia, cancer, coronary heart disease (CHD) and stroke in 2007/08 and assess whether the levels of research expenditure are aligned with disease and economic burden.

METHODS

We identified UK governmental agencies and charities providing health research funding and determined their levels of funding for dementia, cancer, CHD and stroke. Research funding levels were compared to the number of cases, disability-adjusted life years (DALYs) and economic burden. Economic costs were estimated using data on morbidity, mortality, health and social care use, private costs and other related indicators.

RESULTS

Research funding to the four diseases was £833 million, of which £590 million (71%) was devoted to cancer, £169 million (20%) to CHD, £50 million (6%) to dementia and £23 million (4%) to stroke. Cancer received £482 in research funding per 1000 DALYs lost, CHD received £266, dementia received £166, with stroke receiving £71. In terms of economic burden, for every £1 million of health and social care costs attributable to each disease, cancer received £129 269 in research funding, CHD received £73 153, stroke received £8745 and dementia received £4882.

CONCLUSIONS

Most health research funding in the UK is currently directed towards cancer. When compared to their burden, our analysis suggests that research spending on dementia and stroke is severely underfunded in comparison with cancer and CHD.

The cost-effectiveness of adjuvant chemotherapy for early breast cancer: A comparison of no chemotherapy and first, second, and third generation regimens for patients with differing prognoses

BACKGROUND

The risk of recurrence following surgery in women with early breast cancer varies, depending upon prognostic factors. Adjuvant chemotherapy reduces this risk; however, increasingly effective regimens are associated with higher costs and toxicity profiles, making it likely that different regimens may be cost-effective for women with differing prognoses. To investigate this we performed a cost-effectiveness analysis of four treatment strategies: (1) no chemotherapy, (2) chemotherapy using cyclophosphamide, methotrexate, and fluorouracil (CMF) (a first generation regimen), (3) chemotherapy using Epirubicin-CMF (E-CMF) or fluorouracil, epirubicin, and cyclophosphamide (FEC60) (a second generation regimens), and (4) chemotherapy with FEC60 followed by docetaxel (FEC-D) (a third generation regimen). These adjuvant chemotherapy regimens were used in three large UK-led randomised controlled trials (RCTs).

METHODS

A Markov model was used to simulate the natural progression of early breast cancer and the impact of chemotherapy on modifying this process. The probability of a first recurrent event within the model was estimated for women with different prognostic risk profiles using a parametric regression-based survival model incorporating established prognostic factors. Other probabilities, treatment effects, costs and quality of life weights were estimated primarily using data from the three UK-led RCTs, a meta-analysis of all relevant RCTs, and other published literature. The model predicted the lifetime costs, quality adjusted life years (QALYs) and cost-effectiveness of the four strategies for women with differing prognoses. Sensitivity analyses investigated the impact of uncertain parameters and model assumptions.

FINDINGS

For women with an average to high risk of recurrence (based upon prognostic factors and any other adjuvant therapies received), FEC-D appeared most cost-effective assuming a threshold of £20,000 per QALY for the National Health Service (NHS). For younger low risk women, E-CMF/FEC60 tended to be the optimal strategy and, for some older low risk women, the model suggested a policy of no chemotherapy was cost-effective. For no patient group was CMF chemotherapy the preferred option. Sensitivity analyses demonstrated cost-effectiveness results to be particularly sensitive to the treatment effect estimate for FEC-D and the future price of docetaxel.

INTERPRETATION

To our knowledge, this analysis is the first cost-effectiveness comparison of no chemotherapy, and first, second, and third generation adjuvant chemotherapy regimens for early breast cancer patients with differing prognoses. The results demonstrate the potential for different treatment strategies to be cost-effective for different types of patients. These findings may prove useful for policy makers attempting to formulate cost-effective treatment guidelines in the field of early breast cancer.

Estimation and external validation of a new prognostic model for predicting recurrence-free survival for early breast cancer patients in the UK

Background:

We aimed to estimate and externally validate a new UK-specific prognostic model for predicting the long-term risk of a first recurrent event (local recurrence, metastatic recurrence, or second primary breast cancer) in women diagnosed with early breast cancer.

Methods:

Using data on the prognostic characteristics and outcomes of 1844 women treated for early breast cancer at the Churchill Hospital in Oxford, parametric regression-based survival analysis was used to estimate a prognostic model for recurrence-free survival. The model, which incorporated established prognostic factors, was externally validated using independent data. Its performance was compared with that of the Nottingham Prognostic Index (NPI) and Adjuvant! Online.

Results:

The number of positive axillary lymph nodes, tumour grade, tumour size and patient age were strong predictors of recurrence. Oestrogen receptor (ER) positivity was shown to afford a moderate protective effect. The model was able to separate patients into distinct prognostic groups, and predicted well at the patient level, mean Brier Accuracy Score=0.17 (s.e.=0.004) and overall C=0.745 (95% CI, 0.717–0.773). Its performance diminished only slightly when applied to a second independent data set. When compared with the NPI, the model was able to better discriminate between women with excellent and good prognoses, and it did not overestimate 10-year recurrence-free survival to the extent observed for Adjuvant! Online.

Conclusion:

The model estimated here predicts well at both the individual patient and group levels, and appears transportable to patients treated at other UK hospitals. Its parametric form permits long-term extrapolation giving it an advantage over other prognostic tools currently in use. A simple point scoring system and reference table allow 5-, 10-, and 15-year predictions from the model to be quickly and easily estimated. The model is also available to download as an interactive computer program.

The economic analyses of the UK prospective diabetes study

An economic analysis was not initially included in the study design of the UK Prospective Diabetes Study (UKPDS). However, data were collected throughout the study on hospital drugs and medications used and these were supplemented near the end of the study by cross-sectional surveys of non-inpatient healthcare use and quality of life. Evaluations of tight vs. less tight blood pressure control, intensive vs. less conventional blood glucose control and metformin showed that each was highly cost-effective and that all could be provided at modest total cost. Further analyses showed that amputations and stroke had particularly severe consequences for quality of life, and that amputations and non-fatal MI had high cost consequences. Finally, patient-level data were used to construct a diabetes outcomes model, which estimates the probability of longer-term complications from patient-specific risk factors and can be used in populations at different stages of diabetes progression. The economic analyses arising from the UKPDS have provided new evidence to clinicians, policymakers and researchers on the consequences of diabetes and the cost-effectiveness of interventions, thereby assisting the development of treatment guidelines and improved standards of care. The analyses also illustrated a number of methodological innovations. Finally, the UKPDS Outcomes Model is gaining widespread acceptance as a validated tool for long-term economic and clinical prediction in diabetes.

Cost-utility analyses of intensive blood glucose and tight blood pressure control in type 2 diabetes (UKPDS 72)

AIMS/HYPOTHESIS

This study estimated the economic efficiency (1) of intensive blood glucose control and tight blood pressure control in patients with type 2 diabetes who also had hypertension, and (2) of metformin therapy in type 2 diabetic patients who were overweight.

METHODS

We conducted cost-utility analysis based on patient-level data from a randomised clinical controlled trial involving 4,209 patients with newly diagnosed type 2 diabetes conducted in 23 hospital-based clinics in England, Scotland and Northern Ireland as part of the UK Prospective Diabetes Study (UKPDS). Three different policies were evaluated: intensive blood glucose control with sulphonylurea/insulin; intensive blood glucose control with metformin for overweight patients; and tight blood pressure control of hypertensive patients. Incremental cost : effectiveness ratios were calculated based on the net cost of healthcare resources associated with these policies and on effectiveness in terms of quality-adjusted life years gained, estimated over a lifetime from within-trial effects using the UKPDS Outcomes Model.

RESULTS

The incremental cost per quality-adjusted life years gained (in year 2004 UK prices) for intensive blood glucose control was 6,028 UK pounds, and for blood pressure control was 369 UK pounds. Metformin therapy was cost-saving and increased quality-adjusted life expectancy.

CONCLUSIONS/INTERPRETATION

Each of the three policies evaluated has a lower cost per quality-adjusted life year gained than that of many other accepted uses of healthcare resources. The results provide an economic rationale for ensuring that care of patients with type 2 diabetes corresponds at least to the levels of these interventions.

A model to estimate the lifetime health outcomes of patients with type 2 diabetes: the United Kingdom Prospective Diabetes Study (UKPDS) Outcomes Model (UKPDS no. 68)

AIMS/HYPOTHESIS

The aim of this study was to develop a simulation model for type 2 diabetes that can be used to estimate the likely occurrence of major diabetes-related complications over a lifetime, in order to calculate health economic outcomes such as quality-adjusted life expectancy.

METHODS

Equations for forecasting the occurrence of seven diabetes-related complications and death were estimated using data on 3642 patients from the United Kingdom Prospective Diabetes Study (UKPDS). After examining the internal validity, the UKPDS Outcomes Model was used to simulate the mean difference in expected quality-adjusted life years between the UKPDS regimens of intensive and conventional blood glucose control.

RESULTS

The model's forecasts fell within the 95% confidence interval for the occurrence of observed events during the UKPDS follow-up period. When the model was used to simulate event history over patients' lifetimes, those treated with a regimen of conventional glucose control could expect 16.35 undiscounted quality-adjusted life years, and those receiving treatment with intensive glucose control could expect 16.62 quality-adjusted life years, a difference of 0.27 (95% CI: -0.48 to 1.03).

CONCLUSIONS/INTERPRETATIONS

The UKPDS Outcomes Model is able to simulate event histories that closely match observed outcomes in the UKPDS and that can be extrapolated over patients' lifetimes. Its validity in estimating outcomes in other groups of patients, however, remains to be evaluated. The model allows simulation of a range of long-term outcomes, which should assist in informing future economic evaluations of interventions in type 2 diabetes.

L-NAME (N omega-nitro-L-arginine methyl ester), a nitric-oxide synthase inhibitor, and WIN 55212-2 [4,5-dihydro-2-methyl-4(4-morpholinylmethyl)-1-(1-naphthalenyl-carbonyl)-6H-pyrrolo[3,2,1ij]quinolin-6-one], a cannabinoid agonist, interact to evoke synergistic hypothermia

Cannabinoids evoke profound hypothermia in rats by activating central CB(1) receptors. Nitric oxide (NO), a prominent second messenger in central and peripheral neurons, also plays a crucial role in thermoregulation, with previous studies suggesting pyretic and antipyretic functions. Dense nitric-oxide synthase (NOS) staining and CB(1) receptor immunoreactivity have been detected in regions of the hypothalamus that regulate body temperature, suggesting that intimate NO-cannabinoid associations may exist in the central nervous system. The present study investigated the effect of N(omega)-nitro-L-arginine methyl ester (L-NAME), a NO synthase inhibitor, on the hypothermic response to WIN 55212-2 [4,5-dihydro-2-methyl-4(4-morpholinylmethyl)-1-(1-naphthalenylcarbonyl)-6H-pyrrolo[3,2,1ij]quinolin-6-one], a selective cannabinoid agonist, in rats. WIN 55212-2 (1-5 mg/kg, i.m.) produced dose-dependent hypothermia that peaked 45 to 90 min post-injection. L-NAME (10-100 mg/kg, i.m.) by itself did not significantly alter body temperature. However, a nonhypothermic dose of L-NAME (50 mg/kg) potentiated the hypothermia caused by WIN 55212-2 (0.5-5 mg/kg). The augmentation was strongly synergistic, indicated by a 2.5-fold increase in the relative potency of WIN 55212-2. The inactive enantiomer of WIN 55212-2, WIN 55212-3 [S-(-)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-napthanlenyl) methanone mesylate] (5 mg/kg, i.m.), did not produce hypothermia in the absence or presence of L-NAME (50 mg/kg), confirming that cannabinoid receptors mediated the synergy. The present data are the first evidence that drug combinations of NOS blockers and cannabinoid agonists produce synergistic hypothermia. Thus, NO and cannabinoid systems may interact to induce superadditive hypothermia.

Cost effectiveness analysis of radon remediation programmes

The economic implications of regulations governing radon gas level identification and remediation in buildings are poorly understood, and attempts to address these issues have been criticised for lack of comparability. It is imperative therefore that a general model for the economic evaluation of radon remediation programmes is adopted to ensure comparability between studies and settings and to increase the usefulness of the results to decision makers. This paper presents general guidelines for the use of cost-effectiveness analysis (CEA) as an economic appraisal tool in the evaluation of radon reduction and prevention programmes. The data requirements for a CEA of radon remediation programmes concern both costs and outcomes. These components are discussed with respect to: programme objectives, comparator choice, perspective, time horizon, discounting, uncertainty, and final ratios. Adhering to clear guidelines concerning these aspects of evaluations will facilitate meaningful evaluation of radon remediation programmes. Finally, by evaluating the radon remediation programmes using methods applied to other health interventions (such as lung cancer prevention interventions), comparisons using the same metric can be made across policy areas.

A double-blind randomized controlled trial and economic evaluation of transurethral resection vs contact laser vaporization for benign prostatic enlargement: a 3-year follow-up

OBJECTIVE

To evaluate the effect of contact laser prostate surgery in the treatment of benign prostatic hyperplasia.

PATIENTS AND METHODS

A prospective double-blind randomized controlled trial of transurethral resection of the prostate (TURP) and contact laser prostatectomy was conducted, with an economic evaluation of both procedures. The primary outcome measure was the change in the American Urologic Association symptom score, with secondary outcome measures being the peak urinary flow rate, treatment-related complications, re-operation rate and health service costs.

RESULTS

The perioperative blood loss and transfusion requirements were statistically significantly lower for laser prostatectomy than for TURP. There was no clinically significant difference between TURP and contact laser prostatectomy in the mean change in symptom scores and flow rates. There were distinct perioperative advantages in favour of the contact laser treatment, but some disadvantages in terms of re-catheterization and re-operation rates.

CONCLUSIONS

Contact laser prostatectomy is a valid treatment for benign prostatic hypertrophy. The performance of contact laser prostatectomy as day-case surgery would have cost advantages to the National Health Service.

The traditional plant treatment, Sambucus nigra (elder), exhibits insulin-like and insulin-releasing actions in vitro

Sambucus nigra (elder) has been documented as a traditional treatment of diabetes. In the present study, an aqueous extract of elder (AEE, 1 g/L) significantly increased 2-deoxy-glucose transport, glucose oxidation and glycogenesis of mouse abdominal muscle in the absence of added insulin (2 x 2 factorial design). in acute 20-min tests, 0.25-1 g/L AEE evoked a stepwise stimulation of insulin secretion from clonal pancreatic beta-cells. The insulin releasing effect of AEE (0.5 g/L) was significantly potentiated by 16.7 mmol/L of glucose and significantly reduced by 0.5 mmol/L of diazoxide. AEE did not further enhance insulin secretion in cells stimulated by 10 mmol/L of L-alanine, 1 mmol/L of 3-isobutyl-1-methylxanthine or a depolarizing concentration of KCl (25 mmol/L). Prior exposure of clonal pancreatic beta-cells to AEE did not alter subsequent stimulation of insulin secretion induced by 10 mmol/L of L-alanine, thereby precluding a detrimental effect on cell viability. The insulinotropic action of AEE was partially dependent upon use of heat during extract preparation. Activity of AEE was heat-stable, acetone-insoluble and unaltered by prolonged exposure to acid/alkali (0.1 mol/L of HCl and NaOH). However, activity was significantly decreased 41% by dialysis to remove components with molecular mass <2000 Da. Sequential extraction with solvents revealed activity in both methanol and water fractions, indicating a cumulative effect of more than one extract constituent. Known constituents of elder, including lectin, rutin and the lipophilic triterpenoid (lupeol) and sterol (beta-sitosterol), did not stimulate insulin secretion. The results demonstrate the presence of insulin-releasing and insulin-like activity in the traditional antidiabetic plant, Sambucus nigra.

Development of bivalent (B/E) vaccines able to neutralize CCR5-dependent viruses from the United States and Thailand

Recombinant envelope glycoproteins prepared from a subtype B (MN) strain and a subtype E (CM244) strain of HIV-1 were combined to create a bivalent vaccine (B/E) effective against viruses circulating in the United States and Asia. Combining the two antigens resulted in formulations that increased the breadth and potency of the inter-subtype neutralizing response. Antibodies to the bivalent vaccine formulation neutralized viruses possessing diverse phenotypes, including syncytia-inducing and non-syncytia-inducing primary isolates, viruses using either the CCR5 or the CXCR4 chemokine receptors, and viruses differing in their sensitivity to soluble CD4. These studies demonstrate for the first time that the magnitude and quality of the immune response to HIV-1 can be improved by combining recombinant envelope glycoproteins from different genetic subtypes.

A cost-effectiveness analysis of a residential radon remediation programme in the United Kingdom

As residential radon programmes of identification and remediation have proceeded, so questions have been raised about their costs and benefits. This study presents a generalizable model for estimating the cost-effectiveness of a radon mitigation programme using the methodological framework now considered appropriate in the economic evaluation of health interventions. Its use will help to inform future discussion of radon remediation and lung cancer prevention programmes. Data from Northamptonshire were analysed, resulting in a societal cost-effectiveness ratio of Pounds Sterling 13250 per life-year gained in 1997. The percentage of houses found to be over the action level, and the percentage of householders who decide to remediate are shown to be important parameters for the cost-effectiveness analysis. Questions are raised about the particular importance of perspective in this type of analysis and suggestions are made for future research directions.

Autoradiographic evidence that intrastriatal administration of adenosine A(1) receptor antisense oligodeoxynucleotide decreases adenosine A(1) receptors in the rat striatum and cortex

In this study, the effect of a phosphorothioated A(1) adenosine receptor antisense oligodeoxynucleotide on A(1) receptor density and mRNA in the striatum and cortex of rats was determined. Receptor autoradiography and in situ hybridization revealed a reduction in striatal and cortical A(1) receptor density and cortical A(1) receptor mRNA, respectively, in antisense-treated brains but not in those treated with a mismatch oligonucleotide. There was no change in A(2) receptor binding. These data imply that the corticostriatal pathway synthesizes A(1) receptors and transports them to its terminals.

The kappa-opioid agonist, U-69593, decreases acute amphetamine-evoked behaviors and calcium-dependent dialysate levels of dopamine and glutamate in the ventral striatum

The effects of a kappa-opioid receptor agonist on acute amphetamine-induced behavioral activation and dialysate levels of dopamine and glutamate in the ventral striatum were investigated. Amphetamine (2.5 mg/kg i.p.) evoked a substantial increase in rearing, sniffing, and hole-poking behavior as well as dopamine and glutamate levels in the ventral striatum of awake rats. U-69593 (0.32 mg/kg s.c.) significantly decreased the amphetamine-evoked increase in behavior and dopamine and glutamate levels in the ventral striatum. Reverse dialysis of the selective kappa-opioid receptor antagonist, nor-binaltorphimine, into the ventral striatum antagonized the effects of U-69593 on amphetamine-induced behavior and dopamine and glutamate levels. Reverse dialysis of low calcium (0.1 mM) into the ventral striatum decreased basal dopamine, but not glutamate, dialysate levels by 91% 45 min after initiation of perfusion. Strikingly, 0.1 mM calcium perfusion significantly reduced the 2.5 mg/kg amphetamine-evoked increase in dopamine and glutamate levels in the ventral striatum, distinguishing a calcium-dependent and a calcium-independent component of release. U-69593 did not alter the calcium-independent component of amphetamine-evoked dopamine and glutamate levels. These data are consistent with the view that a transsynaptic mechanism augments the increase in dopamine and glutamate levels in the ventral striatum evoked by a moderately high dose of amphetamine and that stimulation of kappa-opioid receptors suppresses the calcium-dependent component of amphetamine's effects.

Do alpha2-adrenoceptors play an integral role in the antinociceptive mechanism of action of antidepressant compounds?

Antidepressants are analgesic in the absence or presence of depression. The underlying mechanisms probably involve a complex interplay between several neurotransmitter systems and neuroreceptors. Alpha-adrenoceptors play an important role in pain processing and alpha2-adrenoceptor agonists have been used in clinical pain management so we have investigated whether alpha-adrenoceptor sub-types mediate the antinociceptive activity of antidepressants. Thus, the abdominal constriction assay in mice was used to examine the antinociceptive responses of a diverse range of antidepressants following alpha1- or alpha2-adrenoceptor antagonism. The antidepressants or monoamine reuptake inhibitors included the serotonin selective reuptake inhibitor paroxetine, the serotonin-noradrenaline reuptake inhibitor sibutramine, the resolved (+)- and (-)-enantiomers of the noradrenaline reuptake inhibitor oxaprotiline, plus the tricyclics amitriptyline and dothiepin. All these compounds have been previously shown to be antinociceptive in this paradigm. The respective alpha1- and alpha2-adrenoceptor antagonists prazosin and RX821002 ([2-(2-methoxy-1,-4-benzodioxan-2-yl)-2-imidazoline]) did not produce antinociception though at 1.0 mg kg(-1); s.c., RX821002 but not prazosin blocked clonidine antinociception. The antinociceptive activity produced by sub-maximal doses of amitriptyline, dothiepin, sibutramine, paroxetine, (+)- and (-)-oxaprotiline were all blocked by RX821002 but not by prazosin. Additionally, both morphine and aspirin antinociception was resistant to alpha1- and alpha2-adrenoceptor antagonism. Thus, alpha2- rather than alpha1-adrenoceptors may play an integral role in antidepressant antinociception irrespective of the propensity for inhibiting reuptake of not only noradrenaline but also serotonin. It is probable, however, that other differing pharmacological properties of some antidepressants, such as opioid-like activity, may complicate any empirical correlation between monoamine uptake and analgesia.

Insulin-secreting activity of the traditional antidiabetic plant Viscum album (mistletoe)

Viscum album (mistletoe) has been documented as a traditional treatment of diabetes. In acute 20-min tests, 1-10 mg/ml aqueous extract of mistletoe evoked a stepwise 1.1- to 12.2-fold stimulation of insulin secretion from clonal pancreatic B-cells. This effect was abolished by 0.5 mM diazoxide and prior exposure to extract did not alter subsequent stimulation of insulin secretion induced by 10 mM L-alanine, thereby negating a detrimental effect on cell viability. The insulin-releasing effect of mistletoe extract was unaltered by 16.7 mM glucose, l-alanine (10 mM), 3-isobutyl-1-methylxanthine (IBMX) (1 mM), or a depolarising concentration of KCl (25 mM). The ability of extract to enhance insulin secretion did not depend upon the use of heat during extract preparation and was not mediated by lectins. These results demonstrate the presence of insulin-releasing natural product(s) in Viscum album which may contribute to the reported antidiabetic property of the plant.

Insulin-releasing and insulin-like activity of the traditional anti-diabetic plant Coriandrum sativum (coriander)

Coriandrum sativum (coriander) has been documented as a traditional treatment of diabetes. In the present study, coriander incorporated into the diet (62.5 g/kg) and drinking water (2.5 g/l, prepared by 15 min decoction) reduced hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of coriander (1 mg/ml) increased 2-deoxyglucose transport (1.6-fold), glucose oxidation (1.4-fold) and incorporation of glucose into glycogen (1.7-fold) of isolated murine abdominal muscle comparable with 10(-8) M-insulin. In acute 20 min tests, 0.25-10 mg/ml aqueous extract of coriander evoked a stepwise 1.3-5.7-fold stimulation of insulin secretion from a clonal B-cell line. This effect was abolished by 0.5 mM-diazoxide and prior exposure to extract did not alter subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby negating an effect due to detrimental cell damage. The effect of extract was potentiated by 16.7 mM-glucose and 10 mM-L-alanine but not by 1 mM-3-isobutyl-1-methylxanthine. Insulin secretion by hyperpolarized B-cells (16.7 mM-glucose, 25 mM-KCl) was further enhanced by the presence of extract. Activity of the extract was found to be heat stable, acetone soluble and unaltered by overnight exposure to acid (0.1 M-HCl) or dialysis to remove components with molecular mass < 2000 Da. Activity was reduced by overnight exposure to alkali (0.1 M-NaOH). Sequential extraction with solvents revealed insulin-releasing activity in hexane and water fractions indicating a possible cumulative effect of more than one extract constituent. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in Coriandrum sativum.

Identification of a new member of the tumor necrosis factor family and its receptor, a human ortholog of mouse GITR

The tumor necrosis factor (TNF) and TNF receptor (TNFR) gene superfamilies regulate diverse biological functions, including cell proliferation, differentiation, and survival [1] [2] [3]. We have identified a new TNF-related ligand, designated human GITR ligand (hGITRL), and its human receptor (hGITR), an ortholog of the recently discovered murine glucocorticoid-induced TNFR-related (mGITR) protein [4]. The hGITRL gene mapped to chromosome 1q23, near the gene for the TNF homolog Fas/CD95 ligand [5]. The hGITR gene mapped to chromosome 1p36, near a cluster of five genes encoding TNFR homologs [1] [6]. We found hGITRL mRNA in several peripheral tissues, and detected hGITRL protein on cultured vascular endothelial cells. The levels of hGITR mRNA in tissues were generally low; in peripheral blood T cells, however, antigen-receptor stimulation led to a substantial induction of hGITR transcripts. Cotransfection of hGITRL and hGITR in embryonic kidney 293 cells activated the anti-apoptotic transcription factor NF-kappaB, via a pathway that appeared to involve TNFR-associated factor 2 (TRAF2) [7] and NF-kappaB-inducing kinase (NIK) [8]. Cotransfection of hGITRL and hGITR in Jurkat T leukemia cells inhibited antigen-receptor-induced cell death. Thus, hGITRL and hGITR may modulate T lymphocyte survival in peripheral tissues.

The involvement of opioidergic and noradrenergic mechanisms in nefopam antinociception

Nefopam is a clinically effective analgesic agent used to control mild to moderate pain, whose mechanism of action is unknown. We have investigated the antinociceptive activity of nefopam in the mouse abdominal constriction assay and tail immersion test (48 degrees C). Nefopam was found to possess a high degree of potency against acetic acid-induced visceral nociception (ED50 2.5 mg kg(-1)). In the presence of the opioid receptor antagonists, naloxone or naltrindole, the resulting nefopam dose-response relationships were shifted to the right. Naloxone or naltrindole had no effect upon aspirin (ED50 32.1 mg kg(-1)) or clonidine (ED50 0.061 mg kg(-1)) induced antinociception. Acetorphan (10 mg kg(-1); s.c.), an inhibitor of neutral endopeptidase (EC 3.4.24.11) was able to potentiate nefopam's antinociceptive activity (ED50 1.5 mg kg(-1)). The alpha2-adrenoceptor antagonist, 2-[2-(2-methoxy-1,4-benzodioxanyl)]imidazoline hydrochloride (RX821002; 1 mg kg(-1); s.c.), shifted the dose-response curves for clonidine (ED50 7.1 mg kg(-1)) and nefopam (ED50 5.3 mg kg(-1)) to the right in this assay. Additionally, centrally administered RX821002 (1 microg/5 microl/animal; i.c.v.) reduced both clonidine (ED50 7.2 mg kg(-1)) and nefopam's ED50 15.5 mg kg(-1)) efficacy in the abdominal constriction assay. Nefopam (3 and 7.5 mg kg(-1); s.c.) produced significant antinociceptive effect in the thermal assay. Aspirin and RX821002 were devoid of any significant activity in the tail immersion test. Nefopam was shown to possess RX821002-reversible antinociceptive activity in both the tail immersion test and the abdominal constriction assay. These data suggest the involvement of an opioidergic and noradrenergic component to nefopam's antinociceptive activity in the mouse abdominal constriction assay and tail immersion test. However, the present results are unable to determine if the opioidergic component of nefopam antinociception is through a direct and/or indirect activation of opioid receptors.

Clozapine-induced dopamine levels in the rat striatum and nucleus accumbens are not affected by muscarinic antagonism

The effect of the muscarinic antagonist, scopolamine, was examined for a change in the increase in extracellular dopamine, dihydroxyphenyl acetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindolacetic acid (5-HIAA), induced by haloperidol or clozapine in the striatum and nucleus accumbens of anaesthetised and awake rats, monitored using in vivo cerebral microdialysis. Rats received scopolamine (1 mg kg(-1); s.c.) or vehicle followed by haloperidol (1 mg kg(-1); s.c.) or clozapine (20 mg kg(-1); s.c.). Dopamine, DOPAC, HVA and 5-HIAA overflow into striatal or accumbens perfusates was determined using high performance liquid chromatography with electrochemical detection (HPLC-ECD). Scopolamine failed to modify the clozapine- or haloperidol-induced efflux of dopamine or its metabolites in either the striatum or nucleus accumbens following systemic administration in anaesthetised or awake rats. Although pretreatment with scopolamine tended to produce a smaller increase in the clozapine-induced efflux of DOPAC in striatal perfusates than following clozapine treatment alone, this was not statistically significant. Furthermore, local infusion of scopolamine (100 microM) with clozapine (1 mM) via the microdialysis probe did not attenuate the elevated efflux of dopamine observed following clozapine alone, in either the striatum or nucleus accumbens, in anaesthetised rats. This treatment did prevent the clozapine-induced increase in DOPAC and HVA in the striatum but not the nucleus accumbens. Carbachol (50 microM) infused into the dorsolateral striatum or nucleus accumbens raised extracellular dopamine levels 200% and 150%, respectively above baseline. Our data suggest that the increased efflux of dopamine and its metabolites in the rat basal ganglia following clozapine administration is not significantly dependent upon the interaction of clozapine with muscarinic receptors.

Antihyperglycemic actions of Eucalyptus globulus (Eucalyptus) are associated with pancreatic and extra-pancreatic effects in mice

Eucalyptus globulus (eucalyptus) is used as a traditional treatment for diabetes. In this study, incorporation of eucalyptus in the diet (62.5 g/kg) and drinking water (2.5 g/L) reduced the hyperglycemia and associated weight loss of streptozotocin-treated mice. An aqueous extract of eucalyptus (AEE) (0.5 g/L) enhanced 2-deoxy-glucose transport by 50%, glucose oxidation by 60% and incorporation of glucose into glycogen by 90% in mouse abdominal muscle. In acute, 20 min incubations, 0.25-0.5 g AEE/L evoked a stepwise 70-160% enhancement of insulin secretion from the clonal pancreatic beta-cell line (BRIN-BD11). The stimulatory effect of 0.5 g/L AEE was unaltered by the presence of 400 micromol diazoxide/L and prior exposure to AEE did not alter subsequent insulin secretory response to L-alanine, thereby negating adetrimental effect on cell viability. The effect of AEE was not potentiated by glucose or demonstrable in cells exposed to a depolarizing concentration of KCl. Further study of the insulin-releasing effects of AEE revealed the activity to be heat stable, acetone insoluble, stable to acid, but abolished by exposure to alkali. Sequential extraction with solvents revealed activity in both methanol and water fractions, indicating the presence of more than one biologically active extract constituent. These data indicate that Eucalyptus globulus represents an effective antihyperglycemic dietary adjunct for the treatment of diabetes and a potential source for discovery of new orally active agent(s) for future therapy.

ALS/MND and the perspective of health economics

In health care, choices are constantly being made about alternative uses of scarce resources, and health economics offers a framework for analysing these choices and for improving resource allocation. In cost-effectiveness analysis, the costs and consequences of alternatives are systematically measured and compared, with the objective of achieving maximum health gain with the available resources. Treatment options for patients with ALS/MND are severely limited, but riluzole has been shown to offer modest improvements in survival. However, decision-makers are likely to want convincing evidence on the cost-effectiveness of this therapy before recommending widespread adoption. Here, some initial estimates of cost-effectiveness are provided, using published effectiveness data and considering only the costs of therapy and of tracheostomy. Compared with placebo, the incremental cost per life year gained of 50 mg/day of riluzole is pound sterling 45630, and of 100 mg/day is pound sterling 44890. Increasing the estimated costs of tracheostomy reduces the cost per life year gained of 50 mg/day to pound sterling 34940. However, if quality of life during the increased period of survival is 80% of full health, the cost per quality adjusted life year gained of 50 mg/day becomes pound sterling 57040. These cost-effectiveness ratios are well in excess of the range that is normally considered to be acceptable in UK health technology assessment. However, the comparatively small number of ALS/MND patients and the lack of treatment alternatives should also be considered. Meanwhile, better information on costs is required in order to produce more precise estimates of cost-effectiveness.

Actions of the traditional anti-diabetic plant, Agrimony eupatoria (agrimony): effects on hyperglycaemia, cellular glucose metabolism and insulin secretion

Agrimony eupatoria (agrimony) has been documented as a traditional treatment of diabetes. Here, the effects of dietary administration of agrimony on streptozotocin (STZ)-diabetic mice and on in vitro glucose uptake and glucose metabolism, and on insulin secretion by BRIN-BD11 cells were investigated. Agrimony incorporated into the diet (62.5 g/kg) and drinking water (2.5 g/l) countered the weight loss, polydipsia, hyperphagia and hyperglycaemia of STZ-diabetic mice. Aqueous extract of agrimony (1 mg/ml) stimulated 2-deoxy-glucose transport (1.4-fold), glucose oxidation (1.4-fold) and incorporation of glucose into glycogen (2.0-fold) in mouse abdominal muscle comparable with 0.1 microM-insulin. In acute 20 min tests, 0.25-1 mg/ml aqueous extract of agrimony evoked a stepwise 1.9-3.8-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0.5 mM-diazoxide and previous exposure to extract did not adversely affect subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby indicating that there was no detrimental effect of the extract on cell viability. The effect of extract was glucose-independent and was not evident in BRIN-BD11 cells exposed to a depolarizing concentration of KCl. The ability of agrimony extract to enhance insulin secretion was dependent on use of heat during extract preparation. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in Agrimony eupatoria.

The involvement of the opioidergic system in the antinociceptive mechanism of action of antidepressant compounds

1. Debate exists as to the nature of antidepressant-induced antinociception. It is unclear whether antidepressants are inherently antinociceptive, are able to potentiate opioid antinociception or both. We have used the acetic acid induced abdominal constriction assay in mice to investigate antidepressant-induced antinociception. 2. All the antidepressants tested (s.c.) produced dose-dependent protection against acetic acid-induced abdominal constriction. Similarly, morphine and aspirin were also effective antinociceptive agents in this nociceptive assay. 3. Opioid antagonists, naloxone (0.5 mg kg(-1), s.c.) and naltrindole (1 mg kg(-1), s.c.), shifted the dose-response relationships to the right for each of the antidepressant agents (dothiepin, amitriptyline, sibutramine, (+)-oxaprotiline and paroxetine). In this context the naloxone dose-ratios were 1.95, 3.90, 2.32, 4.50 and 2.65, with naltrindole dose-ratios of 4.36, 17.00, 4.28, 11.48 and 2.65 were obtained, respectively. Naloxone also shifted the morphine dose-response relationship to the right, by a factor of 2.62, whilst naltrindole had no effect upon morphine antinociception. Aspirin antinociception remained unaffected by both opioid antagonists. 4. The enkephalin catabolism inhibitor acetorphan, by itself, produced no activity in this test at a dose of 10 mg kg(-1) (s.c.). However, at higher doses, acetorphan produced a linear dose-response relationship against acetic acid-induced abdominal constriction. 5. When acetorphan was administered before either the antidepressants or morphine, there was a clear potentiation of the antidepressant- or morphine-induced antinociception. However, acetorphan had no effect on aspirin antinociception. 6. Since neither of the opioid antagonists were able to attenuate, nor was acetorphan able to potentiate, aspirin antinociception, we concluded that the mechanism of antidepressant-induced antinociception is different from that of the non-steroidal anti-inflammatory drugs. 7. These data are consistent with the view that antidepressants may induce endogenous opioid peptide release, as shown by the acetorphan study. In this context, the ability of naltrindole to displace the antidepressant dose-response relationship to the right without affecting morphine antinociception, implicates the delta-opioid receptor and endogenous opioid peptides in antidepressant-induced antinociception.

Insulin-releasing and insulin-like activity of Agaricus campestris (mushroom)

Agaricus campestris (mushroom) has been documented as a traditional treatment for diabetes. Here the administration of mushroom in the diet (62.5 g/kg) and drinking water (2.5 g/l) countered the hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of mushroom (1 mg/ml) stimulated 2-deoxyglucose transport (2.0-fold), glucose oxidation (1.5-fold) and incorporation of glucose into glycogen (1.8-fold) in mouse abdominal muscle. In acute 20 min tests, 0.25-1 mg/ml aqueous extract of mushroom evoked a stepwise 3.5- to 4.6-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0.5 mM diazoxide and prior exposure to extract did not affect subsequent stimulation of insulin secretion by 10 mM L-alanine, thereby negating a detrimental effect on cell viability. The effect of extract was potentiated by 16.7 mM glucose, L-alanine (10 mM) and IBMX (1 mM), and a depolarising concentration of KCl (25 mM) did not augment the insulin-releasing activity of mushroom. Activity of the extract was found to be heat stable, acetone soluble and unaltered by exposure to alkali, but decreased with exposure to acid. Dialysis to remove components with molecular mass < 2000 Da caused a 40% reduction in activity. Sequential extraction with solvents revealed insulin-releasing activity to be greatest in polar fractions. Lack of haemagglutinin activity with extract activity indicated that activity was unlikely to be due to a lectin-mediated event. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in A. campestris.

Power and sample size calculations for stochastic cost-effectiveness analysis

As the data for economic analyses are increasingly collected prospectively alongside clinical trials, many commentators have highlighted that the sample sizes in such trials should be based on the requirements for the economic analysis as well as those for the clinical evaluation. However, issues associated with sample size calculations for economic analysis have yet to receive the rigorous attention given to sample size calculation for clinical evaluation. In particular, no sample size formula for cost-effectiveness analysis is available for analysts hoping either to calculate the required sample size at the design stage of a study or to calculate the power a given size of clinical trial will generate for cost-effectiveness analysis. Building on the recent literature for calculating confidence intervals for cost-effectiveness ratios, the authors explore possible techniques for deriving a sample size formula for cost-effectiveness analysis based on simple combination of the confidence limits on costs and effects.

Gastric inhibitory polypeptide and effects of glycation on glucose transport and metabolism in isolated mouse abdominal muscle

This study investigates the effects of gastric inhibitory polypeptide (GIP) and glycated GIP (glucitol adduct of GIP) on glucose uptake and metabolism in muscle. Glycated GIP (molecular mass 5147.2 Da) was purified by HPLC following in vitro incubation under hyperglycaemic reducing conditions (24 h at pH 7.4). GIP (10(-10)-10(-8) mol/l) significantly stimulated (1.4- to 1.5-fold, P < 0.001) 2-deoxy-D-[1-3H]glucose uptake in abdominal muscle pieces from 3- to 5-week-old lean mice compared with control incubations (without GIP). This stimulatory effect on glucose uptake at 10(-10)-10(-9) mol/l was decreased by 13-20% following glycation of the peptide (P < 0.05). GIP (10(-9) and 10(-8) mol/l) induced a stepwise 1.4- to 1.7-fold increase (P < 0.01, P < 0.001 respectively) in [14C]glucose oxidation compared with controls. This effect on glucose oxidation was diminished by 32% with 10(-8) mol/l glycated GIP (P < 0.05). GIP (10(-9) and 10(-8) mol/l) induced a 1.4- to 1.8-fold increase in [14C]glucose incorporation into muscle glycogen (glycogenesis) compared with controls. Glycated GIP (10(-8) mol/l) exhibited a 41% decrease in glycogenic activity (P < 0.01). GIP (10(-10)-10(-8) mol/l) stimulated lactate production in isolated abdominal muscle (1.2- to 1.3-fold, P < 0.05); however glycated GIP did not exert a significant effect. This study demonstrates for the first time that GIP promotes glucose uptake, glucose oxidation and glycogenesis in muscle tissue. Furthermore, modification of GIP through glycation diminishes its biological effectiveness.

An economic analysis of varicella vaccination for health care workers

A simulation model was constructed to assess the relative costs and cost-effectiveness of different screening and vaccination strategies for dealing with hospital incidents of varicella exposure, compared with current policies, using data from published sources and a hospital survey. The mean number of incidents per hospital year was 3.9, and the mean annual cost of managing these incidents was pounds 5170. Vaccination of all staff would reduce annual incidents to 2.2 at a net cost of pounds 48,900 per incident averted. Screening all staff for previous varicella, testing those who are uncertain or report no previous varicella, and vaccinating those who test negative for VZV antibodies, reduces annual incidents to 2.3 and gives net savings of pounds 440 per incident averted. Sensitivity analyses do not greatly alter the ranking of the options. Some form of VZV vaccination strategy for health care workers may well prove a cost-effective use of health care resources.

Genetic and immunologic characterization of viruses infecting MN-rgp120-vaccinated volunteers

Proviral sequences were determined and immunologic characterization was carried out for envelope glycoproteins from 7 vaccinees who became infected with human immunodeficiency virus type 1 (HIV-1), through high-risk behavior, while participating in clinical trials of MN-rgp120, a candidate HIV-1 vaccine. All 7 infections resulted from subtype B viruses; however, only 3 of the viruses possessed the MN serotype-defining V3 domain sequence, IGPGRAF, prevalent in 60%-70% of US infections. Six of the 7 viruses differed from MN-rgp120 at a neutralizing epitope in the C4 domain, and all 7 differed from MN-rgp120 at a neutralizing epitope in the V2 domain. Recombinant gp120 was prepared from each breakthrough specimen and tested for binding to a panel of neutralizing monoclonal antibodies. The results suggest that 6 of 7 breakthrough infections may be related to incomplete immunization or to infection with viruses that differed from the vaccine immunogen at important virus-neutralizing epitopes.

Pancreatic and extra-pancreatic effects of the traditional anti-diabetic plant, Medicago sativa (lucerne)

Medicago sativa (lucerne) is used as a traditional plant treatment of diabetes. In the present study, administration of lucerne in the diet (62.5 g/kg) and drinking water (2.5 g/l) reduced the hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of lucerne (1 mg/ml) stimulated 2-deoxy-glucose transport (1.8-fold), glucose oxidation (1.7-fold) and incorporation of glucose into glycogen (1.6-fold) in mouse abdominal muscle. In acute 20 min tests, 0.25-1 mg/ml aqueous extract of lucerne evoked a stepwise 2.5-6.3-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0.5 mM-diazoxide, and prior exposure to extract did not affect subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby negating a detrimental effect on cell viability. The effect of extract was potentiated by 16.7 mM-glucose and by 1 mM-3-isobutyl-1-methylxanthine. L-Alanine (10 mM) and a depolarizing concentration of KCl (25 mM) did not augment the insulin-releasing activity of lucerne. Activity of the extract was found to be heat stable and largely acetone insoluble, and was enhanced by exposure to acid and alkali (0.1 M-HCl and NaOH) but decreased 25% with dialysis to remove components with molecular mass < 2000 Da. Sequential extraction with solvents revealed insulin-releasing activity in both methanol and water fractions indicating a cumulative effect of more than one extract constituent. The results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in the traditional antidiabetic plant, Medicago sativa.

Intrastriatal adenosine A1 receptor antisense oligodeoxynucleotide blocks ethanol-induced motor incoordination

Intrastriatal administration of a 21-mer phosphorothioate antisense oligodeoxynucleotide targeting the adenosine A1 receptor blocked ethanol-induced motor incoordination in the rat and reduced striatal adenosine A1 receptor content, as judged by specific binding of the A1-specific ligand 8-cyclopentyl-1,3-dipropylxanthine (Bmax = 0.350 +/- 0.07, Kd = 1.87 +/- 0.50 nM). No effect upon striatal adenosine A2 receptor content was observed (Bmax = 0.415 +/- 0.04, Kd = 13.13 +/- 1.25 nM) with the A2-specific ligand 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine. A mismatched control oligodeoxynucleotide of identical G-C base composition and general sequence structure was without effect on adenosine A1 receptor (Bmax = 0.666 +/- 0.11, Kd = 1.32 +/- 0.27 nM) or adenosine A2 receptor content (Bmax = 0.501 +/- 0.08; Kd = 14.65 +/- 1.82 nM) or ethanol-induced motor incoordination. These results confirm an important role of the striatal adenosine A1 receptor in mediating certain motor-related physiological effects of ethanol.

The cost of cardiac rehabilitation services in England and Wales

A random sample of 25 cardiac rehabilitation programmes in England and Wales was surveyed by questionnaire. Using workload and resource data returned, costs were calculated per centre, per patient and per session. Sixteen (64%) of the centres returned full details. Annual staffing costs per cardiac rehabilitation centre were in the range 10,000 Pounds to 62,000 Pounds, with a mean of just under 33,0000 Pounds (median 32,000 Pounds). Mean cost per patient completing the rehabilitation programme was 370 Pounds (median 223 Pounds), and mean cost per patient per session was 47 Pounds (median 26 Pounds). There was substantial intercentre variation in costs. Cost per patient was closely related to patient throughput and hours of contact time. The costs of rehabilitation programmes in this survey exceed earlier estimates. To assess the implications for the cost-effectiveness of such programmes, reliable data on the effectiveness of such programmes are now required.

Problems in conducting economic evaluations alongside clinical trials. Lessons from a study of case management for people with mental disorders

BACKGROUND

Case management has become the statutory basis of community care in the UK for people with long-term mental disorders, although a randomised controlled trial found no important improvements over standard care. Here we compare the costs and cost consequences of this intervention with standard care.

METHOD

Resource-use data were collected over a six-month baseline period and for 14 months after randomisation on all patients in the trial.

RESULTS

At 14 months the ratio of control group to treatment group weekly costs was 1.09 (95% CI 0.86-1.38) for total costs; 1.12 (0.76-1.65) for state benefits, and 1.21 (0.61-2.42) for health care costs. Costs were thus lower in the treatment group, but these differences were not significant.

CONCLUSIONS

Retrospective power calculations indicated that the trial could have detected differences of 30% in total cost, but would have required 700 patients per arm to detect a 20% difference in health care costs. Hence this study, which had adequate power to detect clinically meaningful differences, was found to be far too small to detect large differences in costs. Funding agencies increasingly request that clinical trials include economic alongside clinical end-points: these findings may have important lessons for that policy.

Effects of non-glycated and glycated glucagon-like peptide-1(7-36) amide on glucose metabolism in isolated mouse abdominal muscle

This study investigated the actions of non-glycated and glycated glucagon-like peptide-1(7-36)amide (tGLP-1) on glucose uptake and metabolism in isolated mouse abdominal muscle. Monoglycated tGLP-1 (Mr 3463.8) was prepared under hyperglycemic reducing conditions and purified by HPLC. Non-glycated tGLP-1 (10(-10)-10(-8) mol/l) stimulated both 2-deoxy-D-[1-3H]glucose uptake (1.3-1.5 fold) and 14C-glucose oxidation (1.4-1.7 fold) in muscle compared to controls without tGLP-1. Glycation reduced these stimulatory effects by 27-33% and 25% (at 10(-9) mol/l), respectively. tGLP-1 (10(-10)-10(-8) mol/l) promoted muscle glycogenesis and lactate production, whereas glycated peptide was ineffective below 10(-9) mol/l. This study demonstrates that tGLP-1 has potent glycogenic effects in mouse abdominal muscle in vitro and that glycation impairs its action.

The costs of nursing turnover: evidence from the British National Health Service

This article reports empirical evidence on the costs of nursing and other staff turnover in the National Health Service. It begins by considering the possible costs and benefits associated with turnover. It then examines current turnover rates in the NHS and existing estimates of the direct administrative costs and the short-term productivity losses associated with turnover. Using these estimates, it compares the cost-effectiveness of a policy which uses across-the-board pay increases to reduce turnover with one which targets pay rises to certain groups only. Next, possible indirect costs of turnover are evaluated using data collected from a large cross-section of providers and other sources. No relationship is found between turnover rates and crude measures of patient service or staff morale measures. The paper concludes with a brief discussion of the main findings and some suggestions for future research.

Effect of alprazolam on opiate withdrawal: a combined behavioural and microdialysis study

Benzodiazepines are commonly abused concurrently with opioids. The pharmacological rationale for this remains unknown. The present study has addressed behaviourally and neurochemically the action of alprazolam on the naloxone-precipitated morphine withdrawal syndrome in male rats. In naloxone (1 mg kg-1 i.p.)-precipitated morphine withdrawn rats, alprazolam (2.5 mg kg-1 s.c.) reduced the severity of the affective component, as measured by squeal on touch hostility, and the physical sequelae of opioid withdrawal. The microdialysis study in anaesthetized rats identified an increase in noradrenaline levels in hippocampal dialysates in rats undergoing naloxone-precipitated opioid withdrawal. Acute treatment with alprazolam (2.5 mg kg-1 s.c.) 20 min before administration of naloxone prevented the previously identified increase in noradrenaline in hippocampal dialysates. The only observable effect alprazolam induced in non-morphine-dependent rats was a 15% reduction in spontaneous locomotor activity. In conclusion, one interpretation of the data suggests that alprazolam decreases the withdrawal syndrome in rats through dampening down the previously identified hyperactivity of the locus coeruleus.

Hexose recognition by insulin-secreting BRIN-BD11 cells

Clonal BRIN-BD11 cells were produced by electrofusion of NEDH rat islet B-cells with immortal RINm5F cells. Western blotting analysis revealed that unlike RINm5F, novel BRIN-BD11 cells expressed high levels of the glucose transport protein GLUT-2, coupled with a rapid and sustained uptake of D-glucose, significantly greater than RINm5F after only 5 min (p < 0.05). Whereas BRIN-BD11 cells expressed a high glucokinase:hexokinase ratio with 1.4-2.0 fold and 1.4-1.7 fold stepwise stimulation of insulin secretion with 4.2-16.7 mM D-glucose and D-mannose respectively, RINm5F had a lower glucokinase:hexokinase ratio (p < 0.001) and were notably unresponsive to D-glucose and D-mannose. Unlike RINm5F cells, BRIN-BD11 were unresponsive to other hexoses, with RINm5F only responding to D-galactose (p < 0.05). BRIN-BD11 cells should be useful for studies of nutrient-induced insulin secretion.