Fatal Human Rabies Infection With Suspected Host-Mediated Failure of Post-Exposure Prophylaxis Following a Recognized Zoonotic Exposure-Minnesota, 2021

BACKGROUND

No human rabies post-exposure prophylaxis (PEP) failure has been documented in the United States using modern cell culture-based vaccines. In January 2021, an 84-year-old male died from rabies 6 months after being bitten by a rabid bat despite receiving timely rabies PEP. We investigated the cause of breakthrough infection.

METHODS

We reviewed medical records, laboratory results, and autopsy findings and performed whole-genome sequencing (WGS) to compare patient and bat virus sequences. Storage, administration, and integrity of PEP biologics administered to the patient were assessed; samples from leftover rabies immunoglobulin were evaluated for potency. We conducted risk assessments for persons potentially exposed to the bat and for close patient contacts.

RESULTS

Rabies virus antibodies present in serum and cerebrospinal fluid were nonneutralizing. Antemortem blood testing revealed that the patient had unrecognized monoclonal gammopathy of unknown significance. Autopsy findings showed rabies meningoencephalitis and metastatic prostatic adenocarcinoma. Rabies virus sequences from the patient and the offending bat were identical by WGS. No deviations were identified in potency, quality control, administration, or storage of administered PEP. Of 332 persons assessed for potential rabies exposure to the case patient, 3 (0.9%) warranted PEP.

CONCLUSIONS

This is the first reported failure of rabies PEP in the Western Hemisphere using a cell culture-based vaccine. Host-mediated primary vaccine failure attributed to previously unrecognized impaired immunity is the most likely explanation for this breakthrough infection. Clinicians should consider measuring rabies neutralizing antibody titers after completion of PEP if there is any suspicion for immunocompromise.

Combined effect of toe out gait and high tibial osteotomy on knee adduction moment in patients with varus knee deformity

BACKGROUND

Gait adaptations, including toe out gait, have been proposed as treatments for knee osteoarthritis. The clinical application of toe out gait, however, is unclear. This study aims to identify the changes in Knee adduction moment in varus knee deformity assessing toe out gait as an alternative to high tibial osteotomy, and if any change in dynamic loading persists post operatively, when anatomical alignment is restored.

METHODS

Three-dimensional motion analysis was performed on 17 patients with medial compartment knee osteoarthritis and varus deformity prior to undergoing high tibial osteotomy, 13 patients were assessed post-operatively, and results compared to 13 healthy controls.

FINDINGS

Pre-operatively, there was no significant difference between natural and toe out gait for measures of knee adduction moment. Post high tibial osteotomy, first (2.70 to 1.51% BW·h) and second peak (2.28 to 1.21% BW·h) knee adduction moment were significantly reduced, as was knee adduction angular impulse (1.00 to 0.52% BW·h·s), to a healthy level. Adopting toe out gait post-operatively reduced the second peak further to a level below that of healthy controls.

INTERPRETATION

Increasing the foot progression angle from 20° (natural) to 30° in isolation did not significantly alter the knee adduction moment or angular impulse. This suggests that adopting a toe out gait, in isolation, in an already high natural foot progression angle, is not of benefit. Adopting toe out gait post-operatively, however, resulted in a further reduction in the second peak to below that of the healthy control cohort, however, this may increase lateral compartment load.

Acceptability of unsupervised HPV self-sampling using written instructions

Objectives

The study measured the acceptability of self-sampling for human papillomavirus (HPV) testing in the context of cervical cancer screening. Women carried out self-sampling unsupervised, using a written instruction sheet.

Setting

Participants were women attending either a family planning clinic or a primary care trust for routine cervical screening.

Methods

Women (n = 902) carried out self-sampling for HPV testing and then a clinician did a routine cervical smear and HPV test. Immediately after having the two tests, participants completed a measure of acceptability for both tests, and answered questions about ease of using the instruction sheet and willingness to use self-sampling in the future.

Results

The majority of women found self-sampling more acceptable than the clinician-administered test, but there was a lack of confidence that the test had been done correctly. Significant demographic differences in attitudes were found, with married women having more favourable attitudes towards self-sampling than single women, and Asian women having more negative attitudes than women in other ethnic groups. Intention to use self-sampling in the future was very high across all demographic groups.

Conclusion

Self-sampling for HPV testing was highly acceptable in this large and demographically diverse sample, and women were able to carry out the test alone, using simple written instructions. Consistent with previous studies, women were concerned about doing the test properly and this issue will need to be addressed if self-sampling is introduced. More work is needed to see whether the demographic differences we found are robust and to identify reasons for lower acceptability among single women and those from Asian background.

Genetic association of the activin A receptor gene (ACVR2A) and pre-eclampsia

Pre-eclampsia is a common serious disorder of human pregnancy, which is associated with significant maternal and perinatal morbidity and mortality. The suspected aetiology of pre-eclampsia is complex, with susceptibility being attributable to multiple environmental factors and a large genetic component. Recently, we reported significant linkage to chromosome 2q22 in 34 Australian/New Zealand (Aust/NZ) pre-eclampsia/eclampsia families, and activin A receptor type IIA (ACVR2A) was identified as a strong positional candidate gene at this locus. In an attempt to identify the putative risk variants, we have now comprehensively re-sequenced the entire coding region of the ACVR2A gene and the conserved non-coding sequences in a subset of 16 individuals from these families. We identified 45 single nucleotide polymorphisms (SNPs), with 9 being novel. These SNPs were genotyped in our total family sample of 480 individuals from 74 Aust/NZ pre-eclampsia families (including the original 34 genome-scanned families). Our best associations between ACVR2A polymorphisms and pre-eclampsia were for rs10497025 (P = 0.025), rs13430086 (P = 0.010) and three novel SNPs: LF004, LF013 and LF020 (all with P = 0.018). After correction for multiple hypothesis testing, none of these associations reached significance (P > 0.05). Based on these data, it remains unclear what role, if any, ACVR2A polymorphisms play in pre-eclampsia risk, at least in these Australian families. However, it would be premature to rule out this gene as significant associations between ACVR2A SNPs and pre-eclampsia have recently been reported in a large Norwegian (HUNT) population sample.

Objective prioritization of positional candidate genes at a quantitative trait locus for pre-eclampsia on 2q22

Pre-eclampsia/eclampsia (PE/E) is a common, serious medical disorder of human pregnancy. Familial association of PE/E has been recognized for decades, but the genetics are complex and poorly understood. In an attempt to identify PE/E susceptibility genes, we embarked on a positional cloning strategy using 34 Australian and New Zealand PE/E pedigrees. An initial 10-cM resolution genome scan revealed a putative susceptibility locus spanning a broad region on chromosome 2 that overlaps an independently determined linkage signal seen in Icelandic PE pedigrees. Subsequent fine mapping using 25 additional short tandem repeat (STR) markers in this region and non-parametric multipoint linkage analysis did not change the overall position. Under a strict diagnosis of PE, we obtained significant evidence of linkage on 2q with a peak log-of-odds ratio score (LOD) of 3.43 near marker D2S151 at 155 cM. To prioritize positional candidate genes at the 2q locus for detailed analysis, we applied an objective prioritization strategy that integrates quantitative bioinformatics, assessment of differential gene expression and association analysis of single-nucleotide polymorphisms (SNPs). Highest priority was assigned to the activin receptor gene ACVR2. This gene also showed >10-fold differential gene expression in human decidual tissue from normotensive and PE individuals. We genotyped five known SNPs in this gene in our pedigrees and performed tests for association and linkage disequilibrium. One SNP (rs1424954) showed strong preliminary evidence of association with PE (P = 0.007), whereas two others (rs1364658 and rs1895694) exhibited nominal evidence (P < 0.05). Haplotype analysis revealed no additional association information. There was evidence of weak linkage disequilibrium among these SNPs. The highest observed LD occurred between the two strongest associated SNPs, suggesting that the observed signals may be the signature of an observed functional variant.

Fine mapping and SNP analysis of positional candidates at the preeclampsia susceptibility locus (PREG1) on chromosome 2

Genome scans in Icelandic, Australian and New Zealand, and Finnish families have localized putative susceptibility loci for preeclampsia/ eclampsia to chromosome 2. The locus mapped in the Australian and New Zealand study (designated PREG1) was thought to be the same locus as that identified in the Icelandic study. In both these studies, two distinct quantitative trait locus (QTL) regions were evident on chromosome 2. Here, we describe our fine mapping of the PREG1 locus and a genetic analysis of two positional candidate genes. Twenty-five additional microsatellite markers were genotyped within the 74-cM linkage region defined by the combined Icelandic and Australian and New Zealand genome scans. The overall position and shape of the localization evidence obtained using nonparametric multipoint analysis did not change from that seen previously in our 10-cM resolution genome scan; two peaks were displayed, one on chromosome 2p at marker D2S388 (107.46 cM) and the other on chromosome 2q at 151.5 cM at marker D2S2313. Using the robust two-point linkage analysis implemented in the Analyze program, all 25 markers gave positive LOD scores with significant evidence of linkage being seen at marker D2S2313 (151.5 cM), achieving a LOD score of 3.37 under a strict diagnostic model. Suggestive evidence of linkage was seen at marker D2S388 (107.46 cM) with a LOD score of 2.22 under the general diagnostic model. Two candidate genes beneath the peak on chromosome 2p were selected for further analysis using public single nucleotide polymorphisms (SNPs) within these genes. Maximum LOD scores were obtained for an SNP in TACR1 (LOD = 3.5) and for an SNP in TCF7L1 (LOD = 3.33), both achieving genome-wide significance. However, no evidence of association was seen with any of the markers tested. These data strongly support the presence of a susceptibility gene on chromosome 2p11-12 and substantiate the possibility of a second locus on chromosome 2q23.

Attitudes to self-sampling for HPV among Indian, Pakistani, African-Caribbean and white British women in Manchester, UK

Objective: To examine attitudes to self-sampling for human papillomavirus (HPV) testing among women from contrasting ethnic groups.

Setting: Manchester, UK.

Methods: Two hundred women of Indian, Pakistani, African-Caribbean and white British origin were recruited from social and community groups to participate in a questionnaire survey. The questionnaire included items on attitudes to self-sampling and intention to use the test.

Results: Willingness to try to use the test was high, and women did not foresee religious or cultural barriers to self-sampling; however, a large proportion of women were concerned about doing the test properly. This concern was greatest in the Indian and African-Caribbean groups.

Conclusions: Although women's willingness to try self-sampling for HPV is encouraging, worries about carrying out the procedure correctly must be addressed if women are to feel confident about the results of self-sampling methods and reassured by a negative result.

Pupil-led sex education in England (RIPPLE study): cluster-randomised intervention trial

BACKGROUND

Improvement of sex education in schools is a key part of the UK government's strategy to reduce teenage pregnancy in England. We examined the effectiveness of one form of peer-led sex education in a school-based randomised trial of over 8000 pupils.

METHODS

29 schools were randomised to either peer-led sex education (intervention) or to continue their usual teacher-led sex education (control). In intervention schools, peer educators aged 16-17 years delivered three sessions of sex education to 13-14 year-old pupils from the same schools. Primary outcome was unprotected (without condom) first heterosexual intercourse by age 16 years. Analysis was by intention to treat.

FINDINGS

By age 16 years, significantly fewer girls reported intercourse in the peer-led arm than in the control arm, but proportions were similar for boys. The proportions of pupils reporting unprotected first sex did not differ for girls (8.4% intervention vs 8.3% control) or for boys (6.2% vs 4.7%). Stratified estimates of the difference between arms were -0.4% (95% CI -3.7% to 2.8%, p=0.79) for girls and -1.4% (-4.4% to 1.6%, p=0.36) for boys. At follow-up (mean age 16.0 years [SD 0.32]), girls in the intervention arm reported fewer unintended pregnancies, although the difference was borderline (2.3% vs 3.3%, p=0.07). Girls and boys were more satisfied with peer-led than teacher-led sex education, but 57% of girls and 32% of boys wanted sex education in single-sex groups.

INTERPRETATION

Peer-led sex education was effective in some ways, but broader strategies are needed to improve young people's sexual health. The role of single-sex sessions should be investigated further.

Evaluating the impact of training in psychosocial interventions: a stakeholder approach to evaluation--part I

A range of psychosocial interventions (PSI) have developed as approaches to the treatment and support of people with enduring mental health problems and their carers. The impact of training mental health workers in PSI has also been subject to extensive research and evaluation for the past decade. Most previous research in the PSI and PSI training arenas have tended to adopt quasi-experimental designs and professionally defined outcomes-focused approaches to judging the success of training. This paper offers a critique of such approaches and presents a rationale for the methodology used in a qualitative study that evaluated five short PSI courses. The study emphasized a stakeholder approach to evaluation, involving collaborative activities between service users, carers, lecturers and mental health workers. These activities were intended to define what outcomes should be used to judge the success of training and how these should be examined during the research process. This paper details the processes and findings of these stakeholder activities that suggested, for service users particularly, process rather than outcome issues were the most important determinants of the success of PSI. Additionally, if outcomes were used to judge the success of interventions these should be highly individualized to reflect the aspirations of the person receiving the intervention. On the basis of the findings presented, discussion explores a proposal for a different methodological direction to the evaluation of PSI training. Part II of this paper presents and discusses the findings from the evaluation of the courses.

Evaluating the impact of training in psychosocial interventions: a stakeholder approach to evaluation--part II

Part I of this article presented an examination of the methodology used in previous psychosocial interventions (PSI) research and the rationale for the collaborative, qualitative design used in this study. In this second article the findings from an evaluation of five short PSI training courses are presented. Findings demonstrated that while the training was positively evaluated by participants and seen to be relevant to practice, the actual dissemination of PSI training into practice was a complex and context dependent process. There was difficulty for course participants in using PSI in practice as discrete, formal interventions. Rather the predominant way participants used PSI in practice was via a process of modifying PSI. The course philosophy, content and mode of delivery impacted on how the respondents constructed PSI as an overall approach to care and working relationships. Participants reported other 'hidden' benefits of training, such as reaffirming practice, increasing confidence and perhaps most powerfully, a change in attitude linked to the importance and impact attached to the service user and carer involvement in delivering the courses. Discussion locates the findings within the findings from previous PSI training evaluations and recommendations are made for a reappraisal of approaches to PSI training and research.

Disruption of a novel member of a sodium/hydrogen exchanger family and DOCK3 is associated with an attention deficit hyperactivity disorder-like phenotype

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a complex condition with high heritability. However, both biochemical investigations and association and linkage studies have failed to define fully the underlying genetic factors associated with ADHD. We have identified a family co-segregating an early onset behavioural/developmental condition, with features of ADHD and intellectual disability, with a pericentric inversion of chromosome 3, 46N inv(3)(p14:q21).

METHODS

We hypothesised that the inversion breakpoints affect a gene or genes that cause the observed phenotype. Large genomic clones (P1 derived/yeast/bacterial artificial chromosomes) were assembled into contigs across the two inversion breakpoints using molecular and bioinformatic technologies. Restriction fragments crossing the junctions were identified by Southern analysis and these fragments were amplified using inverse PCR.

RESULTS

The amplification products were subsequently sequenced to reveal that the breakpoints lay within an intron of the dedicator of cytokinesis 3 (DOCK3) gene at the p arm breakpoint, and an intron of a novel member of the solute carrier family 9 (sodium/hydrogen exchanger) isoform 9 (SLC9A9) at the q arm. Both genes are expressed in the brain, but neither of the genes has previously been implicated in developmental or behavioural disorders.

CONCLUSION

These two disrupted genes are candidates for involvement in the pathway leading to the neuropsychological condition in this family.

A school-based randomized controlled trial of peer-led sex education in England

This article discusses the design of an ongoing cluster-randomized trial comparing two forms of school-based sex education in terms of educational process and sexual health outcomes. Twenty-nine schools in southern England have been randomized to either peer-led sex education or to continue with their traditional teacher-led sex education. The primary objective is to determine which form of sex education is more effective in promoting young people's sexual health. The trial includes an unusually detailed evaluation of the process of sex education as well as the outcomes. The sex education programs were delivered in school to pupils ages 13-14 years who are being followed until ages 19-20. Major trial outcomes are unprotected sexual intercourse and regretted intercourse by age 16 and cumulative incidence of abortion by ages 19-20. We discuss the rationale behind various aspects of the design, including ethical issues and practical challenges of conducting a randomized trial in schools, data linkage for key outcomes to reduce bias, and integrating process and outcome measures to improve the interpretation of findings.

Awareness of human papillomavirus among women attending a well woman clinic

OBJECTIVES

To assess the level and accuracy of public understanding of human papillomavirus (HPV) in the United Kingdom.

METHODS

Women attending a well woman clinic were asked to complete a questionnaire assessing HPV awareness and specific knowledge about the virus.

RESULTS

Questionnaires were completed by 1032 women, of whom 30% had heard of HPV. Older women, non-smokers, and those with a history of candida, genital warts, or an abnormal smear result were more likely to have heard of HPV. Even among those who had heard of HPV, knowledge was generally poor, and fewer than half were aware of the link with cervical cancer. There was also confusion about whether condoms or oral contraceptives could protect against HPV infection.

CONCLUSIONS

In this relatively well educated sample, awareness and knowledge of HPV were poor. Public education is urgently needed so that women participating in cervical cancer screening are fully informed about the meaning of their results, especially if HPV testing is soon to be introduced.

Attitudes towards HPV testing: a qualitative study of beliefs among Indian, Pakistani, African-Caribbean and white British women in the UK

This study examined attitudes to human papillomavirus (HPV) testing among a purposively selected sample of women from four ethnic groups: white British, African Caribbean, Pakistani and Indian. The design was qualitative, using focus group discussion to elicit women's attitudes towards HPV testing in the context of cervical cancer prevention. The findings indicate that although some women welcomed the possible introduction of HPV testing, they were not fully aware of the sexually transmitted nature of cervical cancer and expressed anxiety, confusion and stigma about HPV as a sexually transmitted infection. The term 'wart virus', often used by medical professionals to describe high-risk HPV to women, appeared to exacerbate stigma and confusion. Testing positive for HPV raised concerns about women's sexual relationships in terms of trust, fidelity, blame and protection, particularly for women in long-term monogamous relationships. Participation in HPV testing also had the potential to communicate messages of distrust, infidelity and promiscuity to women's partners, family and community. Concern about the current lack of available information about HPV was clearly expressed and public education about HPV was seen as necessary for the whole community, not only women. The management of HPV within cervical screening raises important questions about informed participation. Our findings suggest that HPV testing has the potential to cause psychosocial harm to women and their partners and families.

Involving mental health service users and carers in curriculum development: moving beyond 'classroom' involvement

Recent policy statements that address the future priorities for nurse education have emphasized that service users and carers should be actively engaged in partnerships with education professionals in all aspects of the curriculum. The development of this agenda is well advanced; however, examples of 'how to do it' are sparse. The development of a strategy to involve users and carers in the design and delivery of the Diploma of Higher Education in Nursing at Napier University provided an opportunity to evaluate the process of developing partnerships in this area of nurse education. This paper presents the findings from a process evaluation from the various standpoints of the key interest groups. The overall project and evaluation is outlined, along with methodological and practical issues surrounding this type of 'collaborative' evaluation. The importance and satisfaction of practical aspects of the project are examined. The issues of representativeness, expertise in 'involvement' and the importance of the 'process' of involvement are explored. Finally, the challenges to developing 'meaningful involvement' that goes beyond 'classroom involvement' in nurse education are identified and discussed.

Studies of vehicular padding materials

The Federal Motor Vehicle Safety Standard 571.201 discusses occupant protection with interior impacts of vehicles. Rule making by the National Highway Traffic Safety Administration (NHTSA) has identified padding for potential injury reduction in vehicles. In these studies, head injury mitigation with padding on vehicular roll bars and brush bars was evaluated. Studies were conducted with free falling Hybrid 50% male head form drops on the forehead and side of the head and a 5% female head. Marked reductions in angular acceleration, as well as Head Injury Criterions (HIC), were observed when compared to unpadded roll bars and brush bars.

The -590C/T and -34C/T interleukin-4 promoter polymorphisms are not associated with atopic eczema in childhood

Susceptibility to the development of asthma and other atopic diseases is known to have a genetic component. To date, several studies have linked chromosome 5q31 to asthma and atopy in human beings. This region harbors a cluster of cytokine and growth factor genes, IL-4 presenting as a prime atopy candidate gene, inasmuch as it plays a pivotal role in the atopy pathway. Our approach was to identify polymorphisms within the promoter regions of IL-4 and test their association with atopic eczema. Polymorphisms were typed in a cohort of 76 small nuclear families and 25 triads with childhood atopic eczema. The genotypes were used to test for linkage in the presence of association with atopic eczema. A new polymorphism, -34C/T, was identified and studied with a known polymorphism, -590C/T. On its own, each polymorphism showed no association with atopic eczema. The 2 polymorphisms were used to generate haplotypes, and a significant result was found for the -590C/-34C haplotype. However, after Bonferroni correction for multiple testing, the association became nonsignificant. Neither polymorphism predisposes to early-onset atopic eczema by itself, but suggestive linkage was found for the -590C/-34C haplotype in this study.

Heterozygous HESX1 mutations associated with isolated congenital pituitary hypoplasia and septo-optic dysplasia

We have previously shown that familial septo-optic dysplasia (SOD), a syndromic form of congenital hypopituitarism involving optic nerve hypoplasia and agenesis of midline brain structures, is associated with homozygosity for an inactivating mutation in the homeobox gene HESX1/Hesx1 in man and mouse. However, as most SOD/congenital hypopituitarism occurs sporadically, the possible contribution of HESX1 mutations to the aetiology of these cases is presently unclear. Interestingly, a small proportion of mice heterozygous for the Hesx1 null allele show a milder SOD phenocopy, implying that heterozygous mutations in human HESX1 could underlie some cases of congenital pituitary hypoplasia with or without midline defects. Accordingly, we have now scanned for HESX1 mutations in 228 patients with a broad spectrum of congenital pituitary defects, ranging in severity from isolated growth hormone deficiency to SOD with panhypopituitarism. Three different heterozygous missense mutations were detected in individuals with relatively mild pituitary hypoplasia or SOD, which display incomplete penetrance and variable phenotype amongst heterozygous family members. Gel shift analysis of the HESX1-S170L mutant protein, which is encoded by the C509T mutated allele, indicated that a significant reduction in relative DNA binding activity results from this mutation. Segregation analysis of a haplotype spanning 6.1 cM, which contains the HESX1 locus, indicated that only one HESX1 mutation was present in the families containing the C509T and A541G mutations. These results demonstrate that some sporadic cases of the more common mild forms of pituitary hypoplasia have a genetic basis, resulting from heterozygous mutation of the HESX1 gene.

Reliable and sensitive detection of premature termination mutations using a protein truncation test designed to overcome problems of nonsense-mediated mRNA instability

The protein truncation test (PTT) is a mutation-detection method used to scan for premature termination (nonsense) mutations. PCR amplification of the DNA or mRNA source material is performed using forward primers containing a T7-promoter sequence and translation initiation signals such that the resultant products can be transcribed and translated in vitro to identify the smaller truncated protein products. mRNA is commonly used as the source material, but success of the PTT and other RNA-based mutation detection methods can be severely compromised by nonsense mutation-induced mRNA decay, a well-documented process that is often overlooked in mutation detection strategies. In this study, we develop an RNA-based PTT that overcomes the problem of mRNA decay by preincubating cells with cycloheximide to stabilise the mutant mRNA. The effectiveness of this method for mutation detection in abundant mRNAs was demonstrated in osteogenesis imperfecta fibroblasts by the protection of type I collagen (COL1A1) mRNA containing nonsense mutations that normally resulted in mutant mRNA degradation. Stabilisation of mutant mismatch repair gene (MLH1) mRNA was also observed in transformed lymphocytes from patients with hereditary nonpolyposis colorectal cancer (HNPCC). Importantly, our strategy also stabilised very low-level (or illegitimate) nonsense-containing transcripts in lymphoblasts from patients with Bethlem myopathy (COL6A1), familial adenomatous polyposis (APC), and breast cancer (BRCA1). The greatly increased sensitivity and reliability of this RT-PCR/PTT protocol has broad applicability to the many genetic diseases in which only blood-derived cells may be readily available for analysis.

Two novel mutations of the FMO3 gene in a proband with trimethylaminuria

The mammalian flavin-containing monooxygenases catalyze the NADPH-dependent N-oxygenation of nucleophilic nitrogen-, sulfur-, and phosphorus-containing chemicals, drugs, and xenobiotics, including trimethylamine. The FMO3 gene encodes the dominant catalytically active isoform present in human liver. We have identified two missense mutations in the coding region of the gene in a proband with trimethylaminuria (TMA): M66I and R492W. Whereas two mutations (P153L, E305X) accounted for TMA in our eight unrelated previously documented Australian families of British origin, the present report is the first evidence of compound heterozygosity for two rare mutations in a proband with this disorder. This suggests that other rarer alleles, also causing TMA, will be found in the same populations.

Exploring the relationship between neutral and selective mutations in cancer

The transformation of normal cells into cancerous cells is an evolutionary process. Populations of precancerous cells reproduce, mutate, and compete for resources. Some of these mutations eventually lead to cancer. We calculate the probability of developing cancer under a set of simplifying assumptions and then elaborate these calculations, culminating in a simple simulation of the cell dynamics. The agent-based model allows us to examine the interactions of mutations critical for the development of cancer that are either evolutionarily neutral or selective. We can also examine the interaction of these mutations with a "mutator phenotype" derived from mutations that raise the mutation rate for the entire cell. The simulations suggest that there must be at least two selectively neutral mutations necessary for the development of cancer and that preventive treatments will be most effective when they increase this number. The model also suggests that selective mutations facilitate the development of cancer, so that the more selective mutations necessary for the development of cancer, the greater the chance of developing it.

Architecture for an artificial immune system

An artificial immune system (ARTIS) is described which incorporates many properties of natural immune systems, including diversity, distributed computation, error tolerance, dynamic learning and adaptation, and self-monitoring. ARTIS is a general framework for a distributed adaptive system and could, in principle, be applied to many domains. In this paper, ARTIS is applied to computer security in the form of a network intrusion detection system called LISYS. LISYS is described and shown to be effective at detecting intrusions, while maintaining low false positive rates. Finally, similarities and differences between ARTIS and Holland's classifier systems are discussed.

Mental health service user involvement in nurse education: exploring the issues

This paper reports on findings and issues arising from a study designed to promote mental health service users' involvement in a preregistration nursing curriculum. Users' views about the knowledge, skills and attributes required by mental health nurses were explored to inform the curriculum design. Strategies that would facilitate long term, active user involvement in the design and delivery of the curriculum were also explored. Findings are presented with concurrent discussion of issues arising from the research process in relation to user involvement in education. The issue of 'conflict' explores findings relating to users' views of a 'good' mental health nurse and inherent conflicts between user and professional views are highlighted. The representativeness of the research participants is explored and debated in relation to service user involvement in nurse education. Finally, the concepts of 'involvement' and 'tokenism' are discussed and recommendations made about how active user involvement in nurse education can be achieved.

Variable efficacy of repeated annual influenza vaccination

Conclusions have differed in studies that have compared vaccine efficacy in groups receiving influenza vaccine for the first time to efficacy in groups vaccinated more than once. For example, the Hoskins study [Hoskins, T. W., Davis, J. R., Smith, A. J., Miller, C. L. & Allchin, A. (1979) Lancet i, 33-35] concluded that repeat vaccination was not protective in the long term, whereas the Keitel study [Keitel, W. A., Cate, T. R., Couch, R. B., Huggins, L. L. & Hess, K. R. (1997) Vaccine 15, 1114-1122] concluded that repeat vaccination provided continual protection. We propose an explanation, the antigenic distance hypothesis, and test it by analyzing seven influenza outbreaks that occurred during the Hoskins and Keitel studies. The hypothesis is that variation in repeat vaccine efficacy is due to differences in antigenic distances among vaccine strains and between the vaccine strains and the epidemic strain in each outbreak. To test the hypothesis, antigenic distances were calculated from historical hemagglutination inhibition assay tables, and a computer model of the immune response was used to predict the vaccine efficacy of individuals given different vaccinations. The model accurately predicted the observed vaccine efficacies in repeat vaccinees relative to the efficacy in first-time vaccinees (correlation 0.87). Thus, the antigenic distance hypothesis offers a parsimonious explanation of the differences between and within the Hoskins and Keitel studies. These results have implications for the selection of influenza vaccine strains, and also for vaccination strategies for other antigenically variable pathogens that might require repeated vaccination.

Identifying genes predisposing to atopic eczema

BACKGROUND

Genetic and environmental factors are known to play a role in the development of atopic diseases, such as asthma, eczema, and rhinitis. However, the atopy gene (or genes) has yet to be defined. Studies of familial asthma have identified several regions that may contain genes predisposing to atopy, but the data for candidate regions do not show agreement, which may be due to heterogeneity, ascertainment bias, or stochastic factors. Factors such as an early age of onset, a positive family history, and a clearly defined phenotype favor a genetic origin and improve the chance of identifying genes that predispose to atopy.

OBJECTIVE

We sought to define genes that predispose to the development of atopic eczema.

METHODS

We have studied nuclear families with multiple cases of early-onset atopic eczema for involvement of the candidate regions on chromosomes 5q31 (IL gene cluster), 11q13 (high-affinity FCepsilon receptor), 14q11.2 (mast cell chymase), and 16p12 (IL-4 receptor alpha-chain, IL4RA gene).

RESULTS

Using a recessive model, we find a maximum parametric log of the odds of linkage score of 2. 25 and nonparametric score of 2.54 (P =.006) for a region on chromosome 5q31, which we postulate contains a gene predisposing to atopic eczema, but lack of support for linkage to 11q13. Transmission disequilibrium tests do not support an association with candidate polymorphisms in the mast cell chymase and IL4RA genes.

CONCLUSION

We have identified a clinically homogeneous cohort of patients with atopic eczema to identify genetic factors predisposing to the development of atopy. We postulate that there are certain loci that predispose to atopy in general and other loci that determine which of the atopic phenotypes is expressed.

Creativity on the edge of chaos

The health care environment is chaotic, with many threats and problems. Despite nursing's resulting discomfort, being able to see the opportunities and the potential within such complexity is freeing. The author illustrates the use of creative thinking in formulating deliberate responses to the unpredictability of chaos. With such innovative actions, the essential nature of professional nursing can be reaffirmed.

Phenotypic variability of Filipino beta(o)-thalassemia/HbE patients in Indonesia

Three Indonesian patients with identical genotypes, each compound heterozygotes for Filipino beta(o)-thalassemia/HbE, expressed different clinical severities. One patient has mild disease and is transfusion independent, while the other two are severely affected and transfusion dependent. The size of the Filipino beta(o)-globin gene deletion was confirmed to be 45 kb, resolving conflicting values given in the literature. Neither ameliorating genetic factors such as alpha-globin gene deletions or the XmnI restriction site polymorphism at position -158 upstream of the (G)gamma-globin gene, nor differences in beta-globin gene haplotype, explain the phenotypic variation. These observations have implications for the development of antenatal diagnosis in Indonesia, as at present it is not possible to give an accurate prediction of severity of phenotype for this common genotype.

Kallmann syndrome gene (KAL-X) is not mutated in schizophrenia

Kallmann syndrome and schizophrenia share several clinical features, including dysfunctional olfactory ability, hypogonadotrophic hypogonadism, an excess of affected males, and psychiatric presentation. Because of this congruence, it has been proposed that up to 70% of male schizophrenics might have mutations affecting the function or expression of the gene mutated in Kallmann syndrome, KAL-X. We identified and studied 9 unrelated males with schizophrenia (as defined by DSM-IIIR criteria) who also have severe anosmia (first percentile of normal range) and low sex drive (seventh percentile of the normal range), and we sequenced the exons and the intron-exon junctions of the KAL-X gene for each. We found no mutations, and conclude that schizophrenia is rarely, if ever, due to a mutation in the coding sequence or splice junctions of KAL-X.

Spinal muscular atrophy: untangling the knot?

Spinal muscular atrophy (SMA), a clinically and genetically heterogeneous group of neuromuscular diseases, is a disorder of motor neurones characterised by degeneration of spinal cord anterior horn cells and muscular atrophy. SMA is an autosomal recessive disorder with a carrier frequency of about 1150. Three candidate genes, the survival motor neurone (SMN) gene, the neuronal inhibitory protein (NAIP) gene, and the p44 (subunit of basal transcription factor TFIIH) gene, have been considered as genes involved in this condition. The region spanning these genes has a complex organisation including duplications, repetitive sequences, truncated genes, and pseudogenes, which makes molecular analysis of this condition difficult. Although deletions have been found in the majority of SMA patients, a few microrearrangements (like duplications, missense mutations, microdeletions, and gene conversions) localised in the telomeric form of the SMN gene have also been reported. The function of the protein encoded by the SMN gene is still not fully understood but recent studies have indicated that it is found intracellularly in gems, novel nuclear structures. Its interaction with other proteins suggests a role in mRNA processing and metabolism. Whether the NAIP gene protein and other apoptosis associated proteins are directly involved in the initial stages of neurone degeneration and apoptosis, or acting downstream on the pathological pathway, has been difficult to determine. Further studies will be required to elucidate possible functional interactions between these proteins.

Using lazy evaluation to simulate realistic-size repertoires in models of the immune system

We describe a method of implementing efficient computer simulations of immune systems that have a large number of unique B- and/or T-cell clones. The method uses an implementation technique called lazy evaluation to create the illusion that all clones are being simulated, while only actually simulating a much smaller number of clones that can respond to the antigens in the simulation. The method is effective because only 0.001-0.01% of clones can typically be stimulated by an antigen, and because many simulations involve only a small number of distinct antigens. A lazy simulation of a realistic number of clones and 10 distinct antigens is 1000 times faster and 10,000 times smaller than a conventional simulation--making simulations of immune systems with realistic-size repertoires computationally tractable.

The ideal role of the nurse teacher in the clinical area: a comparison of the perspectives of mental health, learning difficulties and general nurses

This paper reports findings from a study that explored trained nurses' and student nurses' perceptions of the nurse teachers' ideal role in the clinical area. Findings demonstrate a dichotomy of opinion regarding the ideal role of the nurse teacher in the clinical area that relates to the nursing specialties in which trained nurses work. Trained nurses working in general nursing areas favoured a product-focused, inspectorate supervisory role for nurse teachers. Conversely, trained nurses working in mental health and learning difficulties areas favoured a supportive, supervisory role for the nurse teacher that emphasized the learning process and encouraged reflection. The consequence of the different models used for student nurses' experience of supervision are discussed and the issue of nurse teachers' clinical credibility is explored. It is suggested that trained nurses, nurse teachers and student nurses should be involved in negotiating and constructing the role that nurse teachers play in the clinical area.

Deriving shape space parameters from immunological data

We present a method for deriving shape space parameters that are consistent with immunological data, and illustrate the method by deriving shape space parameters for a model of cross-reactive memory. Cross-reactive memory responses occur when the immune system is primed by one strain of a pathogen and challenged with a related, but different, strain. Much of the nature of a cross-reactive response is determined by the quantity and distribution of the memory cells, raised to the primary antigen, that cross-react with the secondary antigen. B cells with above threshold affinity for an antigen lie in a region of shape space that we call a ball of stimulation. In a cross-reactive response, the intersection of the balls of stimulation of the primary and secondary antigens contains the cross-reactive B cells and thus determines the degree of cross-reactivity between the antigens. We derive formulas for the volume of intersection of balls of stimulation in different shape spaces and show that the parameters of shape space, such as its dimensionality, have a large impact on the number of B cells in the intersection. The application of our method for driving shape space parameters indicates that, for Hamming shape spaces, 20 to 25 dimensions, a three or four letter alphabet, and balls of stimulation of radius five or six, are choices that match the experimental data. For Euclidean shape spaces, five to eight dimensions and balls of stimulation with radius about 20% of the radius of the whole space, match the experimental data.

Human flavin-containing monooxygenase form 3: cDNA expression of the enzymes containing amino acid substitutions observed in individuals with trimethylaminuria

Trimethylaminuria is an autosomal recessive human disorder affecting a small part of the population as an inherited polymorphism. Individuals diagnosed with trimethylaminuria excrete relatively large amounts of trimethylamine in their urine, sweat, and breath, and this results in a fishy odor characteristic of trimethylamine. Activity of the human flavin-containing monooxygenase (FMO) has been proposed to be deficient in trimethylaminuria patients causing a decrease in the metabolism of trimethylamine that results in a fishy body odor. Cohorts of Australian, American, and British individuals suffering from trimethylaminuria have been identified. The human FMO3 cDNA was amplified from lymphocytes of affected patients. We report preliminary evidence of substitutions detected by screening of the cDNA and genomic DNA. The variant human FMO3 cDNA was constructed from wild type human FMO3 cDNA by site-directed mutagenesis as maltose-binding protein fusions. Five distinct human FMO3 mutants were expressed as fusion proteins in Escherichia coli and compared with wild type human FMO3 maltose-binding proteins (FMO3-MBP) for the N-oxygenation of 10-[(N,N-dimethylamino)pentyl]-2-(trifluoromethyl)phenothiazine, tyramine, and trimethylamine. Human Lys158 FMO3-MBP and, to a greater extent, human Glu158 FMO3-MBP efficiently N-oxygenated the three amine substrates. Human Lys158 Ile66 FMO3-MBP, Glu158 Ile66 FMO3-MBP, Lys158 Leu153 FMO3-MBP, and Glu158 Leu153 FMO3-MBP were all constructed as mutants identified as possible FMO3 variants responsible for trimethylaminuria and were found to be inactive as N-oxygenases. The results suggest that mutations at codons 66 and 153 of FMO3 can cause trimethylaminuria in humans. We observed a common polymorphism of Lys to Glu at codon 158 of FMO3 that segregated with almost equal allele frequencies in a number of control Australian and North American samples studied. The Lys158 to Glu158 human FMO3 polymorphism does not decrease trimethylamine N-oxygenation for the cDNA-expressed enzyme and thus does not appear to be causative of trimethyaminuria. The data show that the functional activity of human FMO3 can be significantly altered by amino acid changes that have been observed in individuals with clinically diagnosed trimethylaminuria.

The ecology of echo

Echo is a generic ecosystem model in which evolving agents are situated in a resource-limited environment. The Echo model is described, and the behavior of Echo is evaluated on two well-studied measures of ecological diversity: relative species abundance and the species-area scaling relation. In simulation experiments, these measures are used to compare the behavior of Echo with that of a neutral model, in which selection on agent genotypes is random. These simulations show that the evolutionary component of Echo makes a significant contribution to its behavior and that Echo shows good qualitative agreement with naturally occurring species abundance distributions and species-area scaling relations.

The clinical role of the nurse teacher: an exploratory study of the nurse teacher's present and ideal role in the clinical area

This paper describes a study which aimed to explore the present and ideal role of the nurse teacher in the clinical area from the perspective of: nurse teachers; ward sisters/charge nurses; staff nurses and students nurses undertaking the 'traditional' and Project 2000 programmes of training. The study adopted a qualitative design. Findings from this study demonstrate that the clinical role of the nurse teacher lacks clarity, however, clear criteria emerged as to how trained nurses and student nurses perceived the ideal role. Nurse teachers' role in assuring the quality of the clinical learning environment emerged as a major area of criticism. It was suggested that, if nurse teachers adopted a clinical role that was primarily concerned with supporting clinically based nurses in their teaching role, this served to assure the quality of students' clinical learning experience. In conclusion, it is suggested that for nurse teachers to meet the needs of trained nurses and student nurses in the clinical area, the role must be diverse and flexible. Attempts to prescribe a unimodel approach to deliver the service should be avoided. Rather, the role must be negotiated between teachers, clinical nurses and students, and constructed in a way that best meets the needs of all parties concerned.

Contracting in the NHS quasi-market

This paper examines the development of contracting within the NHS on the basis of the data collected as part of a national survey of English District Health Authorities carried out in late 1994. The paper starts with a discussion of the background to contracting and its evolution during the first 4 years of the NHS internal market. The second section describes the methodology employed in the national survey. The third section presents the results of the survey alongside a discussion of their relevance in terms of the economics of contracting. This section shows the prevalence of different types of contracts and discusses the emergence of the most common type-sophisticated block contracts. Details are provided of how contracts deal with issues such as the measurement of activity, the pricing of projected activity and of activity variances (mainly at marginal cost), as well as the involvement of clinicians in contracting. Other topics explored include the management of extra contractual referrals, contracting for specialized services, arbitration arrangements, the purchaser efficiency index and contracts with the independent sector. The final section offers some concluding thoughts on the current state and future of contracting in the NHS.