Parental involvement in paediatric cancer treatment decisions

This study investigated parents' information needs and involvement in decision-making processes affecting the care of children diagnosed with cancer. Interviews and questionnaires were used to assess parental satisfaction in 50 mothers and 16 fathers responsible for 58 children in an English Paediatric Oncology Unit. Parents reported that doctors contributed almost twice as much to the decision-making process as they did, but parental satisfaction was positively correlated with the amount of information provided when giving informed consent. Satisfaction about their involvement in this process relied heavily upon the level of support received from others. Parents consenting to their child's involvement in non-randomised trials perceived themselves to be under greater pressure from others during the decision-making process while those whose children were further along the treatment trajectory were more uncertain about decisions previously made. Findings indicate that the accessibility, support, information and degree of control afforded to parents by healthcare professionals impacts upon their satisfaction with both the decision-making process and their confidence in the decisions thus made. Information and support tailored to parents' specific needs may therefore enhance satisfaction with clinical decision making and reassure parents about decisions made in the long-term interest of their child's health.

Pulp and paper mill effluents contain neuroactive substances that potentially disrupt neuroendocrine control of fish reproduction

Here we show for the first time that components of pulp and paper mill effluents contain neuroactive substances that may impair fish reproduction. Grab samples of primary and secondary effluent were obtained from a representative pulp and paper mill in Eastern Canada. Effluents were fractionated using classic polarity and polyphenolic extraction methods into solvents of selected polarities (water, ethanol, ethyl acetate, and hexane). By means of in vitro, competitive assays on goldfish (Carassius auratus) brain tissues, the extracts were screened for their ability to interact with enzymes and receptors involved in gamma-aminobutyric acid (GABA), dopamine, glutamate, and acetylcholine-dependent neurotransmission. These neurotransmission pathways have essential regulatory roles in fish reproduction. Radioligand binding to the following neurotransmitter receptors were significantly impacted following in vitro incubations with extracts (percentage change from controls indicated in brackets): dopamine-2 (D2; 21-48% increase), GABA(A) receptor binding (65-67% decrease and 189% increase), N-methyl-o-aspartic acid (NMDA; 26-75% decrease), and muscarinic cholinergic (mACh; 42% increase). Activities of the following neurotransmitter-related enzymeswere significantly impacted: monoamine oxidase (MAO; 14-48% decrease), GABA-transaminase activity (33% decrease and 21-69% increase), and acetylcholinesterase (AChE; 21-50% decrease). No changes in glutamic acid decarboxylase (GAD) activity were detected. These findings provide a novel and plausible mechanism by which pulp and paper mills effluents impair fish reproduction by interacting with neurotransmitter systems. Furtherwork is required to identify the active compounds and explore whether these changes occur in vivo.

Pharmaceuticals in the environment: good practice in predicting acute ecotoxicological effects

Improvements in analytical techniques have led to an increased awareness of the presence of pharmaceuticals in the environment. Concern is now raised as to the potential adverse effects these compounds may have on non-target organisms, particularly under conditions of chronic exposure. There is a paucity of experimental ecotoxicity data available for pharmaceuticals, hence the use of in silico tools to predict toxicity is a pragmatic option. Previous studies have used the ECOSAR program to predict environmental toxicity of pharmaceuticals, however, these models were developed using industrial chemicals and the applicability of the models to predict effects of pharmaceuticals should be carefully considered. In this study ECOSAR was used to assign 364 diverse pharmaceuticals to recognised chemical classes and hence predict their aquatic toxicity. Confidence in the predictions was assessed in terms of whether the assigned class was realistically representative of the pharmaceutical in question. The correlation between experimentally determined toxicity values (where these were available) and those predicted by ECOSAR was investigated in terms of confidence in the prediction. ECOSAR was shown to make reasonable predictions for certain pharmaceuticals considered to be within the applicability domain of the models, but predictions were less reliable for compounds judged to fall outwith the domain of the models. This study is not critical of ECOSAR or the class based approach to predicting toxicity, but demonstrates the importance of using expert judgement to ascertain whether or not use of a particular model is appropriate when the specific chemistry of a query compound is considered.

Classification of chemicals according to mechanism of aquatic toxicity: an evaluation of the implementation of the Verhaar scheme in Toxtree

A number of mechanisms have been identified that can lead to (acute) aquatic toxicity. The assignment of compounds to a particular mechanism of action is important in the development and utilisation of (quantitative) structure-activity relationships ((Q)SARs) for ecotoxicity. Assignment to a mechanism can be difficult; however in 1992 Verhaar et al. published a series of structural rules which aimed to classify compounds according to mechanism of action. Recent interest has seen the Verhaar rules coded into freely available software such as Toxtree available from the European Chemicals Bureau. To date, a complete critical evaluation of these rules has been lacking. Therefore, the aim of this study was to evaluate the Toxtree implementation of the Verhaar rules using two well characterised aquatic toxicity datasets (Pimephales promelas and Tetrahymena pyriformis phenol databases) for which mechanisms of toxic action are well established. The present study highlights rule, and possible coding, errors that may lead to misclassifications. Improvements to both the rules and prediction architecture are suggested. In particular further rules to improve predictions for polar narcosis (class 2) are suggested.

Evaluation of the local anaesthetic activity of 3-aminobenzo[d]isothiazole derivatives using the rat sciatic nerve model

On the basis of computer prediction of biological activity by PASS and toxicity by DEREK, the most promising 32-alkylaminoacyl derivatives of 3-aminobenzo[d]isothiazole were selected for possible local anaesthetic action. This action was evaluated using an in vitro preparation of the isolated sciatic nerve of the rat and compared with lidocaine which was used as a reference compound. QSAR studies showed that the polarizability, polarity and molecular shape of molecules have a positive influence on their local anaesthetic activity, while contributions of aromatic CH and singly bonded nitrogen are negative. Since the estimated PASS probabilities to find local anaesthetic activity in the most active compounds are less than 50%, these compounds may be considered to be possible NCEs.

Outcome of children with nodular lymphocyte predominant Hodgkin lymphoma - a Children's Cancer and Leukaemia Group report

This report describes the clinical outcomes and follow-up records of 42 children with nodular lymphocyte predominant Hodgkin lymphoma (LPHL) treated on United Kingdom Children's Cancer Study Group (UKCCSG) HD1 (1982-1992) and HD2 protocols (1992-2000). The clinical records of 42 children with LPHL treated between 1982 and 2000 were reviewed retrospectively. All 42 had histology reviewed centrally and confirmed as LPHL by an expert panel. In both trials, only patients with stage IA disease had the option of being treated with either involved field radiation alone or combination chemotherapy consisting of chlorambucil, vinblastine, procarbazine and prednisolone (ChlVPP). Patients with all other stages were treated with ChlVPP chemotherapy. Thirty-five patients (83%) presented with early stage disease (Stages I & II). All 42 patients achieved a complete remission (CR). Six children relapsed after primary therapy. The 5- and 10-year relapse-free survival rates were 87% and 82% respectively. Forty-one are currently alive in CR. In conclusion, children with low-stage LPHL treated between 1982 and 2000 according to the UK strategy for classical Hodgkin lymphoma (HL) had an excellent prognosis. There have been no second malignancies or transformations to B-cell non-Hodgkin lymphoma.

Consensus QSAR Models: Do the Benefits Outweigh the Complexity?

This study has assessed the use of consensus regression, as compared to single multiple linear regression, models for the development of quantitative structure-activity relationships (QSARs). To provide a comparison, four data sets of varying size and complexity were analyzed: silastic membrane flux, toxicity of phenols to Tetrahymena pyriformis, acute toxicity to the fathead minnow and flash point. For each data set, a genetic algorithm was used to develop a model population and the performance of consensus models was compared to that of the best single model. Two consensus models were developed, one using the top 10 models, and the other using a subset of models chosen to provide maximal coverage of model space. The results highlight the ability of the genetic algorithm to develop predictive models from a large descriptor pool. However, the consensus models were shown to offer no significant improvements over single regression models, which are as statistically robust as the equivalent consensus models. Consensus models developed from a selection of the best QSARs were shown not to be superior to a selection of diverse in "model space" QSARs. For the data sets analyzed in this study, and in light of the Organization for Economic Cooperation and Development principles for the validation of QSARs, the increase in model complexity when using consensus models does not seem warranted given the minimal improvement in model statistics.

Antioxidant properties of carotenoids: QSAR prediction of their redox potentials

There is a great need to predict the antioxidant properties of molecules such as carotenoids. These compounds are of great interest due to their contribution to various important biological and industrial processes, including toxicity and fate. In our study, redox potentials were compiled from several literature sources. Redox potential values ranged from 537.2 mV for zeaxanthin up to 691.5 mV for beta-carotene; they correspond to the formation of cation radicals, using the standard calomel electrode (SCE). The redox potential values were measured using conventional electrochemical techniques, cyclic voltammetry and Osteryoung square-wave voltammetry. A quantitative structure-activity relationship (QSAR) was developed to model and consequently to predict the values of redox potential. The predicted values of redox potential for four external carotenoids, namely beta-carotene, zeaxanthin, cantaxanthin and astaxanthin, are presented and discussed. They indicate the dependence of redox potential on structure, donor and acceptor groups and polarisability.

Structure-based modelling in reproductive toxicology: (Q)SARs for the placental barrier

The replacement of animal testing for endpoints such as reproductive toxicity is a long-term goal. This study describes the possibilities of using simple (quantitative) structure-activity relationships ((Q)SARs) to predict whether a molecule may cross the placental membrane. The concept is straightforward, if a molecule is not able to cross the placental barrier, then it will not be a reproductive toxicant. Such a model could be placed at the start of any integrated testing strategy. To develop these models the literature was reviewed to obtain data relating to the transfer of molecules across the placenta. A reasonable number of data were obtained and are suitable for the modelling of the ability of a molecule to cross the placenta. Clearance or transfer indices data were sought due to their ability to eliminate inter-placental variation by standardising drug clearance to the reference compound antipyrine. Modelling of the permeability data indicates that (Q)SARs with reasonable statistical fit can be developed for the ability of molecules to cross the placental barrier membrane. Analysis of the models indicates that molecular size, hydrophobicity and hydrogen-bonding ability are molecular properties that may govern the ability of a molecule to cross the placental barrier.

Constituents within pulp mill effluent deplete retinoid stores in white sucker and bind to rainbow trout retinoic acid receptors and retinoid X receptors

Wild female and male white sucker (Catostomus commersoni) inhabiting an area receiving pulp mill effluent had reduced hepatic levels of retinol, didehydroretinol, retinyl esters, and didehydroretinyl esters, while vitamin E levels were unaffected. This disruption of the retinoid system led us to test methanol and dichloromethane extracts from the effluent of 11 pulp mills from across Canada for their ability to bind to rainbow trout (Oncorhynchus mykiss) retinoic acid receptors (RARs) from the gill and retinoid X receptors (RXRs) from the liver. Concentrated extracts of the final effluent from 6 of the 11 pulp mills were able to displace greater than 25% of the receptor-bound [3H]all-trans retinoic acid (RA) or [3H]9-cis RA from trout RARs and RXRs, respectively. The ability of the extracts to displace retinoic acid did not appear to be linked to the pulping or treatment processes. Moreover, extracts with the greatest activity came from thermomechanical mills, suggesting the compounds may originate from the wood furnish. In addition, extracts prepared from wood furnish (wood chips: white spruce [50%], lodgepole pine [47%], and balsam fir [3%]) from one mill were able to displace [3H]RA from the RARs and RXRs. The 4-hydroxy RA, a metabolite of RA that has been shown to be generated in greater quantities in fish exposed to P450-inducing xenobiotics, was able to displace [3H]all-trans RA from trout RARs as effectively as unlabeled all-trans RA. These results suggest that pulp mill effluent may impact the retinoid system of fish at multiple sites, either by decreasing hepatic retinoid stores or through contributing additional ligands (from the wood furnish) that can bind to RA receptors.

Isolated parenchymal lung involvement in children with stage IV Hodgkin's disease: results of the UKCCSG HD8201 and HD9201 studies

We retrospectively reviewed the case notes of 27 patients who were diagnosed with stage IV Hodgkin's disease (HD) because of isolated parenchymal pulmonary involvement on chest radiograph and computerized tomography scan (excluding subcategory E). Ten were boys and 15 had B symptoms. Median age at diagnosis was 13.6 years (range 6.1-16.2). All received 6-8 cycles of ChlVPP (chlorambucil, vinblastine, procarbazine and prednisolone) and two had additional whole lung irradiation (12 Gy). Ten patients (37%) relapsed or progressed. Seven survive following second-line therapy while three died, two of HD and one of secondary acute myeloid leukaemia 4 years from diagnosis. At the time of analysis, the median follow-up of patients was 56 months (range 9-127). The event-free survival (EFS) was 58.4% (95% CI 38.5-75.8%) at both 5 and 10 years from diagnosis, and the overall survival (OS) was 84.2% (95% CI 61.8-94.6%) at both 5 and 10 years from diagnosis. We conclude that the outcome for HD patients defined as stage IV, because of isolated parenchymal lung involvement, is encouraging and compares favourably with other extra lymphatic organ involvement. Combination chemotherapy is effective in achieving long-term remission and whole lung irradiation is unnecessary.

Estimation of mutation rate at human glycophorin A locus in hematopoietic stem cell progenitors

Surveys of human mutant cells exhibit a few individuals with relatively high "outlying" values, which might be explained by rare mutations occurring during development. To estimate how commonly this occurs, mutant red cell frequencies at the glycophorin A locus in 135 neonates and 109 children and adolescents from three research centers are compared with simulations in which mutations arise from successive cycles of binary fission. The simulations predict the data most accurately when the mutation rate in stem cell precursors is about 2-4 x 10(-7) per division cycle, which is similar to previous estimates from adult stem cell divisions. If these mutation rates are accurate, and the number of stem cell divisions during adult life is as low as previously estimated, it is predicted that up to one-sixth of mutant stem cells over a lifetime arose in early life. However, these mutant stem cells would be difficult to detect in surveys because their distribution within the general population is so skewed.

Evaluation of 'Sun-safe': a health education resource for primary schools

The aim of the study was to assess the effectiveness of 'Sun-safe', a computer-based resource designed to promote skin cancer awareness and educate children, aged 10-11 years, about the effects of excessive exposure to the sun and associated skin cancer preventive behaviours. Effectiveness was measured by changes in knowledge, attitudes and behavioural intentions using a self-completed questionnaire. A cluster, controlled evaluation design was used. Twelve schools were randomly allocated to the intervention arms of the study (workbook or computer), with a further four schools acting as controls (no intervention). One school allocated to the computer group had serious technical problems with their computers on the day of the intervention and had to be excluded from the study, leaving six schools in the workbook group and five in the computer group. One class in each of the 15 schools participated. The questionnaire was administered before the intervention, the day after and 6 weeks thereafter. The primary outcome measures were changes in mean scores at 6 weeks. In all, 376 children, 83% of the roll, completed both pre- and 6-week tests. Mixed-model analysis, allowing for pre-intervention score and the cluster effect, showed significant increases in knowledge scores in all three groups [workbook 2.36, 95% confidence interval (CI): 1.66 to 3.05; computer 1.73, 95% CI: 1.00 to 2.46; control 0.93, 95% CI: 0.11 to 1.74], but only the workbook group was significantly better than the control group (1.43, 95% CI: 0.36 to 2.50) and there was no significant difference between the intervention groups (0.63, 95% CI: -0.38 to 1.63). With regard to attitudes, both interventions showed significantly greater increases in scores than the control group, but there was no significant difference between them (workbook 2.37, 95% CI: 1.27 to 3.47; computer 1.92, 95% CI: 0.76 to 3.09; control -0.01, 95% CI: -1.28 to 1.27). Although the mean increases for behavioural intentions scores were small (workbook 0.66, 95% CI: 0.26 to 1.05; computer 1.11, 95% CI: 0.70 to 1.51; control 0.08, 95% CI: -0.37 to 0.52), those for the intervention groups were significantly better than the control group, but were not significantly different from each other. The evaluation showed significant improvements in knowledge, attitudes and behavioural intentions, which were still present 6 weeks after the intervention. This suggests that interventions employing the Sun-safe workbook and computer-based resources could be most usefully put into effect in the week before the start of the summer holidays.

Effectiveness of home based support for older people: systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of home visiting programmes that offer health promotion and preventive care to older people.

DESIGN

Systematic review and meta-analysis of 15 studies of home visiting.

PARTICIPANTS

older people living at home, including frail older people at risk of adverse outcomes.

OUTCOME MEASURES

Mortality, admission to hospital, admission to institutional care, functional status, health status.

RESULTS

Home visiting was associated with a significant reduction in mortality. The pooled odds ratio for eight studies that assessed mortality in members of the general elderly population was 0.76 (95% confidence interval 0.64 to 0.89). Five studies of home visiting to frail older people who were at risk of adverse outcomes also showed a significant reduction in mortality (0.72; 0.54 to 0.97). Home visiting was associated with a significant reduction in admissions to long term institutional care in members of the general elderly population (0.65; 0.46 to 0.91). For three studies of home visiting to frail, "at risk" older people, the pooled odds ratio was 0.55 (0.35 to 0.88). Meta-analysis of six studies of home visiting to members of the general elderly population showed no significant reduction in admissions to hospital (odds ratio 0.95; 0.80 to 1.09). Three studies showed no significant effect on health (standardised effect size 0.06; -0.07 to 0.18). Four studies showed no effect on activities of daily living (0.05; -0.07 to 0.17).

CONCLUSION

Home visits to older people can reduce mortality and admission to long term institutional care.

The use of chemotherapy to facilitate surgical resection in pleomorphic xanthoastrocytoma: experience in a single case

The use of noncytotoxic chemotherapy as an adjuvant treatment to permit resection of a pleomorphic xanthoastrocytoma (PXA) is described. A 6-year-old girl with a large right occipito-temporo-parietal lesion presented with signs and symptoms of raised intracranial pressure. An initial attempt at resection was halted because of excessive blood loss, and tumour embolisation was not feasible as no suitable vascular pedicle was identified. Two cycles of vincristine and carboplatin were given, and these decreased the vascularity of the tumour allowing subsequent complete macroscopic resection 9 weeks later. The use of chemotherapy to decrease the vascularity of the tumour by way of its antiangiogenic effects is discussed.

A systematic, genome-wide, phenotype-driven mutagenesis programme for gene function studies in the mouse

As the human genome project approaches completion, the challenge for mammalian geneticists is to develop approaches for the systematic determination of mammalian gene function. Mouse mutagenesis will be a key element of studies of gene function. Phenotype-driven approaches using the chemical mutagen ethylnitrosourea (ENU) represent a potentially efficient route for the generation of large numbers of mutant mice that can be screened for novel phenotypes. The advantage of this approach is that, in assessing gene function, no a priori assumptions are made about the genes involved in any pathway. Phenotype-driven mutagenesis is thus an effective method for the identification of novel genes and pathways. We have undertaken a genome-wide, phenotype-driven screen for dominant mutations in the mouse. We generated and screened over 26,000 mice, and recovered some 500 new mouse mutants. Our work, along with the programme reported in the accompanying paper, has led to a substantial increase in the mouse mutant resource and represents a first step towards systematic studies of gene function in mammalian genetics.

Informatics for mutagenesis: the design of mutabase--a distributed data recording system for animal husbandry, mutagenesis, and phenotypic analysis

The increasing use of high-throughput methods for the production of biologically important information and the increasing diversity of that information pose considerable bioinformatics challenges. These challenges will be met by implementing electronic data management systems not only to capture the data, but increasingly to provide a platform for data integration and mining as we enter the post-genomic era. We discuss the design and implementation of such a data capture system, 'Mutabase', as a model of how such electronic systems might be designed and implemented. Mutabase was created in support of a large-scale, phenotype-driven mouse mutagenesis program at MRC Mammalian Genetics Unit, Harwell, in collaboration with SmithKline Beecham Pharmaceuticals, Queen Mary and Westfield College, London, and Imperial College of Science, Technology and Medicine, London. The aim of this mutagenesis project is to make a significant contribution to the existing mouse mutant resource, closing the phenotype gap and providing many more models for fundamental research and disease modeling. Mutabase records experimental details at the 'point of generation' and provides a number of dissemination and analysis tools for the experimental data, as well as providing a means of assessing various aspects of progress of the program. Mutabase uses a hypertext-based interface to provide interaction between a number of intranet-based client workstations and a central industrial strength database. Mutabase utilizes a variety of techniques in order to implement the user interface system including Perl/CGI, Java Servlets, and an experimental CORBA server. We discuss the relative merits of these methods in the context of the need to provide sound informatics approaches for the support of systematic mutagenesis programs.