A Methodological Study to Compare Alternative Modes of Administration with Value EQ-5D Using Preference-Elicitation Techniques

OBJECTIVES

Time trade-off (TTO) and discrete choice experiment (DCE) preference-elicitation techniques can be administered using face-to-face interviews (F2F), unassisted online (UO) surveys, or remote-assisted (RA) interviews. The objective of this study was to explore how the mode of administration affects the quality and reliability of preference-elicitation data.

METHODS

EQ-5D-5L health states were valued using composite TTO (cTTO) and DCE approaches by the UK general population. Participants were allocated to 1 of 2 study groups. Group A completed both F2F and UO surveys (n = 271), and group B completed both RA and UO surveys (n = 223). The feasibility of survey completion and the reliability and face-validity of data collected were compared across all modes of administration.

RESULTS

Fewer participants reported receiving sufficient guidance on the cTTO tasks during the UO survey compared with the 2 assisted modes. Participants across all modes typically reported receiving sufficient guidance on the DCE tasks. cTTO data were less reliable from the UO survey compared with both assisted modes, but there were no differences in DCE data reliability. cTTO data from all modes demonstrated face-validity; however, the UO survey produced higher utilities for moderate and severe health states than both assisted modes. Both F2F and RA modes provided comparably reliable data.

CONCLUSIONS

The reliability of DCE data is not affected by the mode of administration. Interviewer-assisted modes of administration (F2F or RA) yield more reliable cTTO data than unassisted surveys. Both F2F and RA surveys produced similar-quality data.

Time for consensus on "high-risk" - Sentinel lymph node biopsy for cutaneous squamous cell carcinoma: An international survey of skin cancer specialists and a literature update

There is an urgent need for evidence-based management of cutaneous squamous cell carcinoma (cSCC), particularly "high-risk" tumours. We performed an online survey of skin cancer specialists to assess cSCC research priorities. Respondents were targeted via the international Skin Cancer OUTcomes consortium (SCOUT) and the UK regional Skin Cancer Outcomes North-East (SCONE) research interest group. Thirty-three respondents completed the survey ([46%; 16/33] were non-UK based). 'Defining a role for sentinel lymph node biopsy (SLNB) in high-risk cSCC' was most commonly ranked either 1st or 2nd research priority by respondents (55%; 18/33), with near-total consensus that SLNB could be useful for the early identification of nodal metastasis in high-risk cSCC (97%; 30/31). On this specific research priority, 24 studies with longitudinal follow-up data were identified. Cumulatively, SLNB for cSCC had positivity and false omission rates of 7.0% and 3.1%, respectively, with false negative rates of 29.0%. Given the lack of consensus on a definition of "high-risk" cSCC, it was unsurprising that only two studies of SLNB for head & neck cSCC utilised comparable selection criteria; reporting the highest positivity rates (8.0%) and lowest false-omission rates (2.4%) and false-negative rates (21.4%) overall. There is multi-disciplinary interest in the role of SLNB for "high-risk" cSCC. It appears to perform best in head and neck cases. A consensus definition of "high-risk" cSCC is urgently required to refine the utility of SLNB and guide risk-directed management.

Eliciting willingness-to-pay to prevent hospital medication administration errors in the UK: a contingent valuation survey

Medication errors are common in hospitals. These errors can result in adverse drug events (ADEs), which can reduce the health and well-being of patients', and their relatives and caregivers. Interventions have been developed to reduce medication errors, including those that occur at the administration stage.

OBJECTIVE

We aimed to elicit willingness-to-pay (WTP) values to prevent hospital medication administration errors.

DESIGN AND SETTING

An online, contingent valuation (CV) survey was conducted, using the random card-sort elicitation method, to elicit WTP to prevent medication errors.

PARTICIPANTS

A representative sample of the UK public.

METHODS

Seven medication error scenarios, varying in the potential for harm and the severity of harm, were valued. Scenarios were developed with input from: clinical experts, focus groups with members of the public and piloting. Mean and median WTP values were calculated, excluding protest responses or those that failed a logic test. A two-part model (logit, generalised linear model) regression analysis was conducted to explore predictive characteristics of WTP.

RESULTS

Responses were collected from 1001 individuals. The proportion of respondents willing to pay to prevent a medication error increased as the severity of the ADE increased and was highest for scenarios that described actual harm occurring. Mean WTP across the scenarios ranged from £45 (95% CI £36 to £54) to £278 (95% CI £200 to £355). Several factors influenced both the value and likelihood of WTP, such as: income, known experience of medication errors, sex, field of work, marriage status, education level and employment status. Predictors of WTP were not, however, consistent across scenarios.

CONCLUSIONS

This CV study highlights how the UK public value preventing medication errors. The findings from this study could be used to carry out a cost-benefit analysis which could inform implementation decisions on the use of technology to reduce medication administration errors in UK hospitals.

Ivermectin for Prevention and Treatment of COVID-19 Infection: A Systematic Review, Meta-analysis, and Trial Sequential Analysis to Inform Clinical Guidelines

BACKGROUND

Repurposed medicines may have a role against the SARS-CoV-2 virus. The antiparasitic ivermectin, with antiviral and anti-inflammatory properties, has now been tested in numerous clinical trials.

AREAS OF UNCERTAINTY

We assessed the efficacy of ivermectin treatment in reducing mortality, in secondary outcomes, and in chemoprophylaxis, among people with, or at high risk of, COVID-19 infection.

DATA SOURCES

We searched bibliographic databases up to April 25, 2021. Two review authors sifted for studies, extracted data, and assessed risk of bias. Meta-analyses were conducted and certainty of the evidence was assessed using the GRADE approach and additionally in trial sequential analyses for mortality. Twenty-four randomized controlled trials involving 3406 participants met review inclusion.

THERAPEUTIC ADVANCES

Meta-analysis of 15 trials found that ivermectin reduced risk of death compared with no ivermectin (average risk ratio 0.38, 95% confidence interval 0.19-0.73; n = 2438; I2 = 49%; moderate-certainty evidence). This result was confirmed in a trial sequential analysis using the same DerSimonian-Laird method that underpinned the unadjusted analysis. This was also robust against a trial sequential analysis using the Biggerstaff-Tweedie method. Low-certainty evidence found that ivermectin prophylaxis reduced COVID-19 infection by an average 86% (95% confidence interval 79%-91%). Secondary outcomes provided less certain evidence. Low-certainty evidence suggested that there may be no benefit with ivermectin for "need for mechanical ventilation," whereas effect estimates for "improvement" and "deterioration" clearly favored ivermectin use. Severe adverse events were rare among treatment trials and evidence of no difference was assessed as low certainty. Evidence on other secondary outcomes was very low certainty.

CONCLUSIONS

Moderate-certainty evidence finds that large reductions in COVID-19 deaths are possible using ivermectin. Using ivermectin early in the clinical course may reduce numbers progressing to severe disease. The apparent safety and low cost suggest that ivermectin is likely to have a significant impact on the SARS-CoV-2 pandemic globally.

Ivermectin for Prevention and Treatment of COVID-19 Infection: A Systematic Review, Meta-analysis, and Trial Sequential Analysis to Inform Clinical Guidelines

BACKGROUND

Repurposed medicines may have a role against the SARS-CoV-2 virus. The antiparasitic ivermectin, with antiviral and anti-inflammatory properties, has now been tested in numerous clinical trials.

AREAS OF UNCERTAINTY

We assessed the efficacy of ivermectin treatment in reducing mortality, in secondary outcomes, and in chemoprophylaxis, among people with, or at high risk of, COVID-19 infection.

DATA SOURCES

We searched bibliographic databases up to April 25, 2021. Two review authors sifted for studies, extracted data, and assessed risk of bias. Meta-analyses were conducted and certainty of the evidence was assessed using the GRADE approach and additionally in trial sequential analyses for mortality. Twenty-four randomized controlled trials involving 3406 participants met review inclusion.

THERAPEUTIC ADVANCES

Meta-analysis of 15 trials found that ivermectin reduced risk of death compared with no ivermectin (average risk ratio 0.38, 95% confidence interval 0.19-0.73; n = 2438; I2 = 49%; moderate-certainty evidence). This result was confirmed in a trial sequential analysis using the same DerSimonian-Laird method that underpinned the unadjusted analysis. This was also robust against a trial sequential analysis using the Biggerstaff-Tweedie method. Low-certainty evidence found that ivermectin prophylaxis reduced COVID-19 infection by an average 86% (95% confidence interval 79%-91%). Secondary outcomes provided less certain evidence. Low-certainty evidence suggested that there may be no benefit with ivermectin for "need for mechanical ventilation," whereas effect estimates for "improvement" and "deterioration" clearly favored ivermectin use. Severe adverse events were rare among treatment trials and evidence of no difference was assessed as low certainty. Evidence on other secondary outcomes was very low certainty.

CONCLUSIONS

Moderate-certainty evidence finds that large reductions in COVID-19 deaths are possible using ivermectin. Using ivermectin early in the clinical course may reduce numbers progressing to severe disease. The apparent safety and low cost suggest that ivermectin is likely to have a significant impact on the SARS-CoV-2 pandemic globally.

Economic evaluations of alcohol prevention interventions: Is the evidence sufficient? A review of methodological challenges

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There are few economic evaluations of alcohol prevention interventions.

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Consideration of impacts beyond an individual’s health in evaluations is limited.

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No published studies using other priority-setting methods in the alcohol area.

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Consideration of wider societal perspectives and health inequalities is minimal.

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Including inter-sectoral costs and consequences in evaluations is challenging.

Public health interventions have unique characteristics compared to health technologies, which present additional challenges for economic evaluation (EE). High quality EEs that are able to address the particular methodological challenges are important for public health decision-makers. In England, they are even more pertinent given the transition of public health responsibilities in 2013 from the National Health Service to local government authorities where new agents are shaping policy decisions.

Addressing alcohol misuse is a globally prioritised public health issue. This article provides a systematic review of EE and priority-setting studies for interventions to prevent and reduce alcohol misuse published internationally over the past decade (2006–2016). This review appraises the EE and priority-setting evidence to establish whether it is sufficient to meet the informational needs of public health decision-makers.

619 studies were identified via database searches. 7 additional studies were identified via hand searching journals, grey literature and reference lists. 27 met inclusion criteria. Methods identified included cost-utility analysis (18), cost-effectiveness analysis (6), cost-benefit analysis (CBA) (1), cost-consequence analysis (CCA) (1) and return-on-investment (1). The review identified a lack of consideration of methodological challenges associated with evaluating public health interventions and limited use of methods such as CBA and CCA which have been recommended as potentially useful for EE in public health. No studies using other specific priority-setting tools were identified.

What is important at the end of life for people with dementia? The views of people with dementia and their carers

BACKGROUND

Approaching end of life is often a time of vulnerability; this is particularly so for people with dementia and their families where loss of capacity and the ability to communicate, make assessment and shared decision-making difficult. Research has consistently shown that improvements in care and services are required to support better quality and more person-centred care for people with dementia towards and at end of life. However, the views of people with dementia about what factors contribute to high-quality care at this time are a neglected area.

AIM

The aim of this study was to identify the aspects of end-of-life care for people with dementia that are most important to them and their carers.

DESIGN

Q-methodology, a mixed method combining qualitative and quantitative techniques to study subjectivity, was used to identify the views of people with mild dementia, their family carers and bereaved carers on end-of-life care for people with dementia. Fifty-seven participants were included in the study.

RESULTS

Four distinct views were identified: family involvement, living in the present, pragmatic expectations and autonomy and individuality. Some areas of consensus across all views included compassionate care, decisions being made by healthcare professionals and information availability when making decisions.

CONCLUSION

Our findings reveal several different views on what is important about end-of-life care for people with dementia; therefore, a 'one-size-fits-all' approach to care is unlikely to be most appropriate. Notwithstanding the differing viewpoints could provide a framework for service providers and commissioners for future care. Copyright © 2016 John Wiley & Sons, Ltd.

Molecular basis for odorant receptor tuning: a short C-terminal sequence is necessary and sufficient for selectivity of mosquito Or8

A birth-and-death evolutionary model for odorant receptor gene repertoires presumes the creation of repertoires with the capacity for high-level diversity and rapid ligand specificity change. This changes the recognised odour space, directly affecting fitness-related behaviours and ultimately affecting adaptation to new environments and resources. The proximate molecular mechanisms underlying the tuning of odorant receptor repertoires, and thus peripheral olfaction, are unclear. In the present study, we report a concrete example of this model of odorant receptor evolution leading to rapid changes in receptor tuning that leave the peripheral neuronal circuitry intact. We identified a conserved odorant receptor gene in mosquitoes, Or8, which in Culex quinquefasciatus underwent a duplication and inversion event. The paralogues differ in only minor structural changes manifesting at the C-terminus. We assessed the specificity of the paralogous odorant receptors and receptor neurones. We found that the functional tuning of the receptor was indeed reflected in minor differences in amino acid structure. Specifically, we found that enantiomeric specificity of these mosquito Or8 paralogues relies on eight C-terminal amino acids encoded in the final exon of the gene; thus, the birth of a paralogous odorant receptor can change the tuning of the peripheral olfactory system.

Effect of recurrent yohimbine on immediate and post-hoc behaviors, stress hormones, and energy homeostatic parameters

Evidence from experimental models has suggested that acute activation of brain stress and anxiety pathways impacts subsequent behaviors that are mediated or modulated by limbic circuitry. There have been limited investigations of prior or chronic activation of these pathways on subsequent limbic-mediated behaviors. In this study, we tested whether recurrent administration of the anxiogenic compound yohimbine (YOH) could have post-injection effects on brain activation, stress hormones, and performance in sucrose self-administration and startle response paradigms. Rats received six injections across two weeks of either 2mg/kg YOH or saline. Behavioral evaluation confirmed the continued efficacy of the YOH regimen, and increased adrenal corticosterone (CORT) was observed. Several days following YOH or SAL administration, cFos, CORT and adrenocorticotropin hormone (ACTH), and behavioral performance were measured. cFos was elevated post-YOH in the hippocampus; ventral tegmental area/zona inserta; and central and medial nuclei of the amygdala. This activation is consistent with a sustained effect of YOH to activate fear and anxiety circuitries in the CNS. CORT but not ACTH was elevated in the YOH-rats following startle testing. Self-administration and startle tests suggested an increase of non-specific activity in the post-YOH rats; there was no increase in sucrose self-administration or startle response per se. Our findings suggest that recurrent YOH administration may prove a useful and reliable model for simulating recurrent stress/anxiety, and that enhancements to the paradigm such as higher or more frequent dosing of YOH could yield stronger or more extensive behavioral effects.

Manure Nutrient Excretion by Lactating Cows Fed Exogenous Phytase and Cellulase

The effect of an exogenous phytase and cellulase-containing enzyme formulation on nutrient digestibility and excretion was evaluated in 24 Holstein cows. Cows were fed corn silage- and alfalfa silage-based diets with or without a cellulase-phytase blend for 31 d in a continuous random design. Treatment groups were balanced for parity, days in milk, and mature-equivalent projected milk yield. Diets contained 37% forage, 18.3% crude protein, 35.4% neutral detergent fiber, 18% acid detergent fiber, and 0.42% P (no supplemental P). Cows were fed once daily in Calan doors and milked 2 times daily. Body weight and milk yield were recorded at each milking. Milk samples were collected on d 28 to 31 at 8 consecutive milkings. On d 28 to 31, fecal grab samples were collected every 8 h, with sampling times advanced by 2 h each day. Feces samples were pooled by cow. Feed and feces samples were analyzed for acid detergent lignin (used as an internal marker) and for N, P, neutral detergent fiber, and acid detergent fiber. Days in milk were similar between treatments, and body weight and milk yield were unaffected by treatment. Cows fed the enzyme formulation had reduced fecal dry matter, neutral detergent fiber, and acid detergent fiber excretion and reduced fecal excretion of N and P. Apparent digestibility of dry matter, acid detergent fiber, neutral detergent fiber, and N tended to increase with the enzyme formulation. Addition of an exogenous phytase and cellulase enzyme formulation to diets for lactating cows reduced fecal nutrient excretion.

Review article: Maternal obesity in pregnancy: is it time for meaningful research to inform preventive and management strategies?

The growing epidemic of obesity in our society has become a major public health issue, with serious social and psychological consequences in addition to the physical health implications. Obesity has reached epidemic proportions globally with a similar rise in prevalence among women in the reproductive age group. This has critical consequences for fetal and maternal health in the antepartum, intrapartum and postpartum periods. The aims of this study were to summarise the implications of maternal obesity on maternal, fetal and neonatal health and to recommend good practice guidelines on the management of this problem. The authors highlight the need for good quality interventional research on maternal obesity while identifying avenues with potential scope for future research in this context.

Giving and receiving of gifts between pharmaceutical companies and medical specialists in Australia

BACKGROUND

This study investigated the 'gift-relationship' between pharmaceutical companies and doctors.

METHODS

The study was based on a survey questionnaire of 823 medical specialists from across Australia. The aim of this study was to investigate gifts offered to medical specialists in Australia by pharmaceutical companies, financial support actively sought by medical specialists for activities other than research and to consider what is ethically appropriate.

RESULTS

A high percentage of specialists received offers of food (96%), items for the office (94%), personal gifts (51%) and journals or textbooks (50%). Most specialists were invited to product launches, symposia or educational events (75-84%) and 52% received offers of travel to conferences. A high proportion of offers were accepted (66-79%) except invitations to product launches (49%), sponsored symposia (53%) and offers of travel that included partners (27%). Fifteen per cent of specialists requested financial support from pharmaceutical companies for activities and items, including conferences, travel, educational activities, salaries and donations to specific funds. The study outlined guidelines on gifts from pharmaceutical companies and differing standards applying to gifts and grants for travel. We found that, although most gifts and requests for support complied with professional and pharmaceutical industry guidelines, some--including personal gifts, tickets to sporting events, entertainment and travel expenses for specialists' partners--did not.

CONCLUSION

To ensure that physicians' judgements are free from real or perceived influence from industry and to maintain public trust, we support a shift towards more conservative standards on gifts and support for travel evident in recent guidelines.

Technical Note: Technique for Dissection and Analysis of the Rumen in Young Calves

This paper discusses a technique used to evaluate rumen development in young calves, including removal, dissection, and analysis of tissue. The method allowed for examination of the different sacs of the rumen (dorsal, ventral, cranial, and caudal) using scanning electron microscopy to measure papillae denseness and histology slides to measure papillae length and width. Computer software was used to produce accurate measurements of papillae. The rumens of young calves were dissected, and samples were taken from the cranial, caudal, ventral, and dorsal sections. Calves were part of a nutrition research study, and dietary treatments did have an effect on development measurements such as length, width, and papillae denseness.

Use of pharmacoeconomics in prescribing research. Part 5: modelling - beyond clinical trials

This paper provides an overview of modelling in the economic evaluation of pharmaceuticals, reflecting the increasing use of models in analyses prepared for reimbursement applications to national and local drug formularies. The paper seeks to demystify the most commonly encountered modelling techniques (extrapolation, decision analysis, Markov modelling and Monte Carlo simulation), and to provide guidance in assessing the quality of submitted or published modelled economic evaluations.

Use of pharmacoeconomics in prescribing research. Part 3: Cost-effectiveness analysis--a technique for decision-making at the margin

This is the third Research Note addressing pharmacoeconomics in prescribing research, reflecting the increasing use of economic evaluation in drug purchasing decisions in a variety of settings. In this segment we provide an overview of the theoretical basis, practical application and methodological limitations of cost-effectiveness analysis (CEA).

Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion

BACKGROUND

Most clinical practice guidelines recommend restrictive red cell transfusion practices with the goal of minimising exposure to allogeneic blood (from an unrelated donor). The purpose of this review is to compare clinical outcomes in patients randomised to restrictive versus liberal transfusion thresholds (triggers).

OBJECTIVES

To examine the evidence on the effect of transfusion thresholds, on the use of allogeneic and/or autologous blood, and the evidence for any effect on clinical outcomes.

SEARCH STRATEGY

Trials were identified by: computer searches of OVID Medline (1966 to December 2000), Current Contents (1993 to Week 48 2000), and the Cochrane Controlled Trials Register (2000 Issue 4). References in identified trials and review articles were checked and authors contacted to identify any additional studies.

SELECTION CRITERIA

Controlled trials in which patients were randomised to an intervention group or to a control group. Trials were included where the intervention groups were assigned on the basis of a clear transfusion "trigger", described as a haemoglobin (Hb) or haematocrit (Hct) level below which a RBC transfusion was to be administered.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed using criteria proposed by Schulz et al. (1995). Relative risks of requiring allogeneic blood transfusion, transfused blood volumes and other clinical outcomes were pooled across trials using a random effects model.

MAIN RESULTS

Ten trials were identified that reported outcomes for a total of 1780 patients. Restrictive transfusion strategies reduced the risk of receiving a red blood cell (RBC) transfusion by a relative 42% (RR=0.58: 95%CI=0.47,0.71). This equates to an average absolute risk reduction (ARR) of 40% (95%CI=24% to 56%). The volume of RBCs transfused was reduced on average by 0.93 units (95%CI=0.36,1.5 units). However, heterogeneity between these trials was statistically significant (p<0.00001) for these outcomes. Mortality, rates of cardiac events, morbidity, and length of hospital stay were unaffected. Trials were of poor methodological quality.

REVIEWER'S CONCLUSIONS

The limited published evidence supports the use of restrictive transfusion triggers in patients who are free of serious cardiac disease. However, most of the data on clinical outcomes were generated by a single trial. The effects of conservative transfusion triggers on functional status, morbidity and mortality, particularly in patients with cardiac disease, need to be tested in further large clinical trials. In countries with inadequate screening of donor blood the data may constitute a stronger basis for avoiding transfusion with allogeneic red cells.

Drug information for consumers: should it be disease or medication specific? Results of a community survey

OBJECTIVE

To investigate the information-seeking behaviour of medicine users.

METHODS

A telephone survey and follow-up in-depth interviews of a random sample of the adult population in the Hunter Region, NSW, Australia. The survey sought information on medicine use, information seeking, and satisfaction and understanding of the information received. In-depth interviews examined the barriers and facilitators of information seeking.

RESULTS

Seven hundred and eighty-six people completed the telephone survey and 58 completed the follow-up interviews. Over half (51%) of the medicine users sought information, primarily to 'manage' their medicines, such as how to use the medicine. Over 30% of the questions asked by users related to 'therapeutic choices', such as how well the medicine worked for a particular condition. Doctors and pharmacists were the most frequent sources of information. A small proportion (10%) reported a potential unmet need for medicines information by indicating they would have liked to ask a question, but did not, or were dissatisfied with the information they received. Barriers to information seeking included perceptions that health care professionals were 'too busy', and that they were unwilling to provide information.

CONCLUSIONS

Physicians and pharmacists continue to play an important role in providing consumers with medicines information. Although the reported level of unmet need was low, a significant proportion identified needs relating to information on therapeutic choice, rather than 'classical' drug information.

IMPLICATIONS

Medicines-related information for the public should include advice on comparative performance of drugs, and be provided within the wider framework of general health information.

Ikirara insertions reveal five new Anopheles gambiae transposable elements in islands of repetitious sequence

Characterization of Anopheles gambiae genomic clones containing Ikirara inverted repeats revealed five novel sequences related to known transposable elements (TEs). One TE is related to the mariner/Tc1 superfamily of class II (DNA-to-DNA) transposons, while four are related to class I (RNA-mediated transposition) elements. Crusoe, the class II element; is most similar to the Caenorhabditis elegans transposon Tc1-like TEs. Vash elements, represented twice in our clones, are related to the Q/T1 family of A. gambiae non-LTR retrotransposable elements. Guildenstern is a member of the RT1 and RT2 non-LTR retrotransposon family. Although RT1 and RT2 elements normally have a highly stereotyped insertion preference for sequences within ribosomal genes, Guildenstern is not located in ribosomal sequence. JuanAg is the first anopheline member of the mosquito non-LTR retrotransposon family of Juan elements that previously had included just the culicine elements JuanA and JuanC. Approximately 753 bp is missing from the central portion of the JuanAg reverse transcriptase gene, where an Ikirara inverted repeat is found in its stead. Ozymandias, the only LTR retrotransposon found in the clones, is most similar to the Drosophila melanogaster 412 element. Single Ikirara inverted repeats were also found adjacent to nontransposable element repetitious sequences. Our analysis suggests that the A. gambiae genome organization could best be described as islands of short-period interspersion repetitious DNA in a sea of long-period interspersion, mostly unique sequence DNA.

Enhancing care for people with asthma: the role of communication, education, training and self-management. 1998 World Asthma Meeting Education and Delivery of Care Working Group

Reduction in the morbidity associated with asthma requires attention to several aspects of the behaviour of health professionals and patients, and to the interactions between these two groups. In this review, what has been learnt about health professional/patient communication and patient education (skills, settings and materials), lay and health professional liaison (including telephone helplines), patient education in low-income countries, the integration of patient education into clinical practice, health professional training and the implementation of guidelines, and the role of national asthma campaigns is drawn together. What changes in public policy would enhance asthma care, and whether the promotion of asthma self-management skills is cost effective are also considered. It is concluded that, although further research is necessary in many areas, well-educated health professionals who recognize the person with asthma as an individual, and who give advice about self-management, can significantly reduce the suffering and costs associated with asthma.

Problems with the interpretation of pharmacoeconomic analyses: a review of submissions to the Australian Pharmaceutical Benefits Scheme

CONTEXT

Pharmacoeconomic analyses are being used increasingly as the basis for reimbursement of the costs of new drugs. Reports of these analyses are often published in peer-reviewed journals. However, the analyses are complex and difficult to evaluate.

OBJECTIVE

To describe the nature of problems encountered in the evaluation and interpretation of pharmacoeconomic analyses used as a basis for reimbursement decisions.

DATA SOURCES

All major submissions to the Department of Health and Aged Care (DHAC) by the pharmaceutical industry for funding made under the Australian Pharmaceutical Benefits Scheme. Specifically, the DHAC's database of submissions that were received between January 1994 and December 1997 were reviewed.

STUDY SELECTION

Of a total of 326 submissions, 218 had serious problems of interpretation and were included in the analysis. The nature of the serious problems reviewed were classified as estimates of comparative clinical efficacy, comparator issues, modeling issues, and calculation errors.

DATA EXTRACTION

All submissions in the DHAC's database were reviewed and data were extracted if both the DHAC evaluators and technical subcommittee considered problems to have a significant bearing on the decisions of the parent committee.

DATA SYNTHESIS

Of a total of 326 submissions, 218 (67%) had significant problems and 31 had more than 1 problem. Of the 249 problems identified, 154 (62%) related to uncertainty in the estimates of comparative clinical efficacy, and 71 (28.5%) related to modeling issues, which included clinical assumptions or cost estimates, used in the construction of the economic models. There were 15 instances of disagreement over the choice of comparator, and serious calculation errors were found on 9 occasions. Overall, 159 problems (64%) were considered to be avoidable.

CONCLUSIONS

Significant problems were identified in these pharmacoeconomic analyses. The intensive evaluation process used in the Australian Pharmaceutical Benefits Scheme allowed for identification and correction of pharmacoecomomic analysis problems, but the resources that are required may be beyond the capacity of many organizations, including peer-reviewed journals.

Assessing new health technologies: lessons to be learned from drugs

Balancing the interests of producers, consumers and purchasers (governments) increases the complexity of evidence-based evaluation of non-drug health technologies.

Oxidative inactivation of thioredoxin as a cellular growth factor and protection by a Cys73-->Ser mutation

Thioredoxin (Trx) is a widely distributed redox protein that regulates several intracellular redox-dependent processes and stimulates the proliferation of both normal and tumor cells. We have found that when stored in the absence of reducing agents, human recombinant Trx undergoes spontaneous oxidation, losing its ability to stimulate cell growth, but is still a substrate for NADPH-dependent reduction by human thioredoxin reductase. There is a slower spontaneous conversion of Trx to a homodimer that is not a substrate for reduction by thioredoxin reductase and that does not stimulate cell proliferation. Both conversions can be induced by chemical oxidants and are reversible by treatment with the thiol reducing agent dithiothreitol. SDS-PAGE suggests that Trx undergoes oxidation to monomeric form(s) preceding dimer formation. We have recently shown by X-ray crystallography that Trx forms a dimer that is stabilized by an intermolecular Cys73-Cys73 disulfide bond. A Cys73-->Ser mutant Trx (C73S) was prepared to determine the role of Cys73 in oxidative stability and growth stimulation. C73S was as effective as Trx in stimulating cell growth and was a comparable substrate for thioredoxin reductase. C73S did not show spontaneous or oxidant-induced loss of activity and did not form a dimer. The results suggest that Trx can exist in monomeric forms, some of which are mediated by Cys73 that do not stimulate cell proliferation but can be reduced by thioredoxin reductase. Cys73 is also involved in formation of an enzymatically inactive homodimer, which occurs on long term storage or by chemical oxidation. Thus, although clearly involved in protein inactivation, Cys73 is not necessary for the growth stimulating activity of Trx.

Site-directed mutagenesis of Lys36 in human thioredoxin: the highly conserved residue affects reduction rates and growth stimulation but is not essential for the redox protein's biochemical or biological properties

Previous studies have demonstrated that a recombinant form of the human redox protein thioredoxin can stimulate the growth rate of Swiss 3T3 murine fibroblasts and that this ability to promote cellular proliferation was dependent upon a redox-active form. A site-directed mutagenesis study of the highly conserved Lys36 adjacent to the two active site cysteines of thioredoxin was performed to determine whether the basic residue was essential for the biochemical and mitogenic properties of human thioredoxin. Two mutants were generated in which the lysine residue was replaced with either glutamic acid (K36E) or leucine (K36L). While K36E and K36L were both redox-active in a thioredoxin-specific assay, the mutants exhibited decreased affinities for thioredoxin reductase relative to wild-type thioredoxin since their respective KM values increased by a factor of 5 and 7. Examination of the secondary structure of the variants by circular dichroism spectroscopy revealed that both mutants had minor variations in the overall structural content when compared to thioredoxin, with K36L being most similar to the wild-type protein. Thermal equilibrium denaturation studies of the variants showed that K36E had a TM of 69.5 degrees C. A TM value for thioredoxin and K36L could not be established because the absence of a plateau above 83 degrees C rendered it difficult to establish an upper base line and, hence, the TM. The two mutants were able to stimulate cellular proliferation, albeit with reduced efficiency when compared with wild-type thioredoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibitors of phospholipid intracellular signaling as antiproliferative agents

The improved understanding of oncogenesis and the involvement of oncogenes and tumor suppressor genes, has led to a rational approach of specific target-directed anti-cancer drug development. Cancer genes have been found to be important not only in the control of cell proliferation but also in the mediation of processes such as drug resistance, metastasis, neo-vascularization (angiogenesis), and apoptosis. These are all important targets in their own right and the development of drugs against specific "upstream" targets in oncogenic or growth factor signal transduction cascades it may be possible to inhibit multiple "downstream" targets. Ultimately, to test the hypothesis that signaling pathways offer good targets for anticancer drug development will take several years of careful clinical study and we cannot say at this time whether the approach will work. There are a small number of compounds in the early stages of clinical development as anticancer agents that may act by inhibiting growth factor signaling pathways. In all cases the activity of the compounds on intracellular signaling pathways was discovered after their identification as antiproliferative agents. There are also compounds in preclinical development that have been specifically developed as inhibitors of growth factor signaling, although their selectivity for tumor cells compared to normal tissue remains to be investigated fully in appropriate animal tumor models. It is possible that a single antisignaling drug by itself may not have the power to completely inhibit tumor growth and a combination of drugs may be needed. It may also take a combination of drugs to prevent the emergence of resistance. Clearly there are several challenges to developing this new class of anticancer drugs, and there will undoubtedly be others that must be faced.

A multisample assay for inhibitors of phosphatidylinositol phospholipase C: identification of naturally occurring peptide inhibitors with antiproliferative activity

A convenient and reliable multisample assay for the screening of inhibitors of the growth factor signalling enzyme phosphatidylinositol specific phospholipase C (PtdInsPLC) has been developed. Three naturally occurring peptide inhibitors of PtdInsPLC have been identified, myroridin K, streptothricin B and edeine, with IC50 values of 8.3, 6.7 and 16.1 microM, respectively. All three peptides inhibited colony formation of HT-29 human colon adenocarcinoma cells, with IC50 values of 7.2, 3.9 and 13.0 microM, respectively. The compounds also inhibited the growth of other human cancer cells in culture. One of the peptides, myroridin K, has previously been reported to have in vivo antitumour activity. It is possible that inhibition of PtdInsPLC is responsible for the cell growth inhibition and antitumour properties of the peptide compounds.

The response to arachidonic acid before and after non-steroidal anti-inflammatory drugs in normotensive and hypertensive rats

OBJECTIVE

To establish equivalent doses of four non-steroidal anti-inflammatory drugs (NSAID) in normotensive and hypertensive rats using inhibition of the fall in blood pressure produced by the injection of arachidonic acid as the measure of equivalence.

DESIGN

An experimental study using two rat models of hypertension and their normotensive controls.

METHODS

Two rat models of hypertension (spontaneously hypertensive rats and two-kidney, one clip rats) and their normotensive controls were studied. The change in blood pressure after intravenous injection of arachidonic acid was measured in anaesthetized rats. Blood pressure was measured from a carotid artery cannula, attached to a pen-recorder. Dose-response curves for the effect of arachidonic acid were established in each type of rat, then the effects of different doses of four NSAID (indomethacin, piroxicam, naproxen and sulindac) on these responses were measured.

RESULTS

Arachidonic acid produced a dose-dependent fall in blood pressure in all rats. However, both types of hypertensive rats sustained a larger fall in blood pressure for a given dose of arachidonic acid than did the normotensive controls. Doses of NSAID were found that inhibited this response in Wistar rats. However, the doses of NSAID that were equivalent in normotensive rats were not equivalent in either type of hypertensive rat; indomethacin had a greater inhibitory effect. As far as could be established, this was not due to differences in the metabolism of the NSAID between normotensive and hypertensive rats.

CONCLUSIONS

The arachidonic acid response can be used as a method of establishing equivalent doses of NSAID in normotensive and hypertensive rats. Hypertensive rats appear to be more sensitive to the effects of arachidonic acid than normotensive rats, independent of the model of hypertension. Doses of NSAID that are equivalent in normotensive rats are not equivalent in hypertensive rats. Indomethacin is more effective in attenuating the effect of arachidonic acid, possibly due to actions other than inhibition of cyclo-oxygenase.

Refold and characterization of recombinant tissue factor pathway inhibitor expressed in Escherichia coli

Human tissue factor pathway inhibitor (TFPI) was expressed in E. coli as a non-glycosylated protein with an additional alanine attached to the aminoterminus of the wild type molecule. High-level expression was obtained with pMON6875, a plasmid containing a tac promoter, Gene 10 leader from bacteriophage T7, methionine-alanine-TFPI coding sequence, and the p22 transcriptional terminator. In this system, TFPI accounted for about 5-10% of the total cell protein. The inclusion bodies containing. TFPI were sulfitolyzed, purified by anion-exchange chromatography, refolded through a disulfide interchange reaction, and further fractionated by Mono S cation exchange chromatography. The Mono S resin resolved a peak of highly active TFPI from relatively inactive and possibly misfolded molecules. The E. coli TFPI was shown to be about two-fold more active, on a molar basis, than full-length human SK hepatoma TFPI in a tissue factor-induced clotting assay in human plasma.

5-Fluorouracil causes alterations in the pharmacokinetic profile of tauromustine in NMRI mice

The pharmacokinetic profiles of 5-fluorouracil (5-FU) and tauromustine (TCNU) were investigated in NMRI mice following their administration either alone or as part of simultaneous or sequential combinations. The profile of 5-FU remained unaltered irrespective of the sequence of administration. However, following simultaneous administration of 5-FU and TCNU or pretreatment with 5-FU, plasma levels of TCNU were decreased by a factor of 2.5-3 as compared with those seen when TCNU was given alone. These decreased plasma levels were explained by an increase in the TCNU volume of distribution, although this was not due to alterations in TCNU plasma protein binding. These sequence-dependent alterations in the pharmacokinetic profile of TCNU correlate with and may explain previously reported differences in the anti-tumour activity and toxicity profile of this combination.

Sequence-dependent activity of 5-fluorouracil plus tauromustine in a transplantable well-differentiated murine colon adenocarcinoma

Previous in vitro studies with 5-Fluorouracil (5-FU) plus Tauromustine (TCNU) demonstrated sequence-dependent effects. This study extended these investigations into an in vivo experimental model, relevant to clinical disease. A transplantable murine adenocarcinoma of the colon, MAC 29, was shown to have stable histology and reproducible growth. This model was used to determine the influence of sequence of administration of this drug combination. Effects ranged from antagonism, with 5-FU given 24 hours before TCNU, to addition, simultaneous treatment, and synergism, 5-FU 24 hours after TCNU. Careful consideration of sequence should be made during the evaluation of this combination in clinical trials.

Secretion of Active Bovine Somatotropin in Escherichia coli

We have expressed a chimeric protein, comprising the LamB secretion signal sequence fused to mature bovine somatotropin (bST), in Escherichia coli. Plasmid constructs with the recA promoter showed significant protein accumulation prior to induction and cell lysis occurred after induction. In contrast, the lacUV5 promoter was tightly regulated. With the lacUV5 promoter, temperature and inducer concentration had significant effects on the total amount of recombinant protein produced and the fraction processed to mature bST. Quantitation of bST from shake flask cultures showed that 1-2 micrograms/ml/OD550 could be released from the periplasm by osmotic shock. N-terminal sequence analysis of the purified protein indicated that the majority of the secreted bST was correctly processed. The bST present in the osmotic shock fraction was judged to be correctly folded by comigration with oxidized methionyl-bST standard on a non-reducing polyacrylamide gel and activity in a bovine liver radioreceptor assay. These results provide a rapid method to produce bST for use in structure-function studies.

Smoking artifacts: factors of source evaluation

Responses from 323 students in communication indicated that credibility factors associated with nonverbal smoking artifacts are not the same as those associated with verbal stimuli; a character factor was absent for nonverbal stimuli. Verbosity, however, may permit inferences regarding potential verbal behavior.