Successful Formulation Window for the design of pharmaceutical tablets with required mechanical properties

Pharmaceutical tablet formulations combine the active ingredient with processing aids and functional components. This paper evaluates compressibility based predictive models for binary and ternary formulations to establish an acceptable range of tablet compression parameters that satisfy prescribed quality target criteria for tablets including minimum tablet strength and processing constraints such as maximum ejection stress and maximum compaction pressure. The concept of Successful Formulation Window (SFW) is introduced. A methodology is proposed to determine the SFW for a given formulation based on compaction simulator data collected for individual formulation components. The methodology is validated for binary and ternary mixtures and lubricated formulations. The SFW analysis was developed to support tablet formulation design to meet mechanical requirements.

Improving reporting of meta-ethnography: The eMERGe reporting guidance

AIMS

The aim of this study was to provide guidance to improve the completeness and clarity of meta-ethnography reporting.

BACKGROUND

Evidence-based policy and practice require robust evidence syntheses which can further understanding of people's experiences and associated social processes. Meta-ethnography is a rigorous seven-phase qualitative evidence synthesis methodology, developed by Noblit and Hare. Meta-ethnography is used widely in health research, but reporting is often poor quality and this discourages trust in and use of its findings. Meta-ethnography reporting guidance is needed to improve reporting quality.

DESIGN

The eMERGe study used a rigorous mixed-methods design and evidence-based methods to develop the novel reporting guidance and explanatory notes.

METHODS

The study, conducted from 2015 - 2017, comprised of: (1) a methodological systematic review of guidance for meta-ethnography conduct and reporting; (2) a review and audit of published meta-ethnographies to identify good practice principles; (3) international, multidisciplinary consensus-building processes to agree guidance content; (4) innovative development of the guidance and explanatory notes.

FINDINGS

Recommendations and good practice for all seven phases of meta-ethnography conduct and reporting were newly identified leading to 19 reporting criteria and accompanying detailed guidance.

CONCLUSION

The bespoke eMERGe Reporting Guidance, which incorporates new methodological developments and advances the methodology, can help researchers to report the important aspects of meta-ethnography. Use of the guidance should raise reporting quality. Better reporting could make assessments of confidence in the findings more robust and increase use of meta-ethnography outputs to improve practice, policy, and service user outcomes in health and other fields. This is the first tailored reporting guideline for meta-ethnography. This article is being simultaneously published in the following journals: Journal of Advanced Nursing, Psycho-oncology, Review of Education, and BMC Medical Research Methodology.

A methodological systematic review of meta-ethnography conduct to articulate the complex analytical phases

BACKGROUND

Decision making in health and social care requires robust syntheses of both quantitative and qualitative evidence. Meta-ethnography is a seven-phase methodology for synthesising qualitative studies. Developed in 1988 by sociologists in education Noblit and Hare, meta-ethnography has evolved since its inception; it is now widely used in healthcare research and is gaining popularity in education research. The aim of this article is to provide up-to-date, in-depth guidance on conducting the complex analytic synthesis phases 4 to 6 of meta-ethnography through analysis of the latest methodological evidence.

METHODS

We report findings from a methodological systematic review conducted from 2015 to 2016. Fourteen databases and five other online resources were searched. Expansive searches were also conducted resulting in inclusion of 57 publications on meta-ethnography conduct and reporting from a range of academic disciplines published from 1988 to 2016.

RESULTS

Current guidance on applying meta-ethnography originates from a small group of researchers using the methodology in a health context. We identified that researchers have operationalised the analysis and synthesis methods of meta-ethnography - determining how studies are related (phase 4), translating studies into one another (phase 5), synthesising translations (phase 6) and line of argument synthesis - to suit their own syntheses resulting in variation in methods and their application. Empirical research is required to compare the impact of different methods of translation and synthesis. Some methods are potentially better at preserving links with the context and meaning of primary studies, a key principle of meta-ethnography. A meta-ethnography can and should include reciprocal and refutational translation and line of argument synthesis, rather than only one of these, to maximise the impact of its outputs.

CONCLUSION

The current work is the first to articulate and differentiate the methodological variations and their application for different purposes and represents a significant advance in the understanding of the methodological application of meta-ethnography.

Developing a reporting guideline to improve meta-ethnography in health research: the eMERGe mixed-methods study

Background

Meta-ethnography is a commonly used methodology for qualitative evidence synthesis. Research has identified that the quality of reporting of published meta-ethnographies is often poor and this has limited the utility of meta-ethnography findings to influence policy and practice.

Objective

To develop guidance to improve the completeness and clarity of meta-ethnography reporting.

Methods/design

The meta-ethnography reporting guidance (eMERGe) study followed the recommended approach for developing health research reporting guidelines and used a systematic mixed-methods approach. It comprised (1) a methodological systematic review of guidance in the conduct and reporting of meta-ethnography; (2) a review and audit of published meta-ethnographies, along with interviews with meta-ethnography end-users, to identify good practice principles; (3) a consensus workshop and two eDelphi (Version 1, Duncan E, Swinger K, University of Stirling, Stirling, UK) studies to agree guidance content; and (4) the development of the guidance table and explanatory notes.

Results

Results from the methodological systematic review and the audit of published meta-ethnographies revealed that more guidance was required around the reporting of all phases of meta-ethnography conduct and, in particular, the synthesis phases 4–6 (relating studies, translating studies into one another and synthesising translations). Following the guidance development process, the eMERGe reporting guidance was produced, comprising 19 items grouped into the seven phases of meta-ethnography.

Limitations

The finalised guidance has not yet been evaluated in practice; therefore, it is not possible at this stage to comment on its utility. However, we look forward to evaluating its uptake and usability in the future.

Conclusions

The eMERGe reporting guidance has been developed following a rigorous process in line with guideline development recommendations. The guidance is intended to improve the clarity and completeness of reporting of meta-ethnographies, and to facilitate use of the findings within the guidance to inform the design and delivery of services and interventions in health, social care and other fields. The eMERGe project developed a range of training materials to support use of the guidance, which is freely available atwww.emergeproject.org(accessed 26 March 2018). Meta-ethnography is an evolving qualitative evidence synthesis methodology and future research should refine the guidance to accommodate future methodological developments. We will also investigate the impact of the eMERGe reporting guidance with a view to updating the guidance.

Study registration

This study is registered as PROSPERO CRD42015024709 for the stage 1 systematic review.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Improving reporting of meta-ethnography: the eMERGe reporting guidance

AIMS

The aim of this study was to provide guidance to improve the completeness and clarity of meta-ethnography reporting.

BACKGROUND

Evidence-based policy and practice require robust evidence syntheses which can further understanding of people's experiences and associated social processes. Meta-ethnography is a rigorous seven-phase qualitative evidence synthesis methodology, developed by Noblit and Hare. Meta-ethnography is used widely in health research, but reporting is often poor quality and this discourages trust in and use of its findings. Meta-ethnography reporting guidance is needed to improve reporting quality.

DESIGN

The eMERGe study used a rigorous mixed-methods design and evidence-based methods to develop the novel reporting guidance and explanatory notes.

METHODS

The study, conducted from 2015 to 2017, comprised of: (1) a methodological systematic review of guidance for meta-ethnography conduct and reporting; (2) a review and audit of published meta-ethnographies to identify good practice principles; (3) international, multidisciplinary consensus-building processes to agree guidance content; (4) innovative development of the guidance and explanatory notes.

FINDINGS

Recommendations and good practice for all seven phases of meta-ethnography conduct and reporting were newly identified leading to 19 reporting criteria and accompanying detailed guidance.

CONCLUSION

The bespoke eMERGe Reporting Guidance, which incorporates new methodological developments and advances the methodology, can help researchers to report the important aspects of meta-ethnography. Use of the guidance should raise reporting quality. Better reporting could make assessments of confidence in the findings more robust and increase use of meta-ethnography outputs to improve practice, policy, and service user outcomes in health and other fields. This is the first tailored reporting guideline for meta-ethnography. This article is being simultaneously published in the following journals: Journal of Advanced Nursing, Psycho-oncology, Review of Education, and BMC Medical Research Methodology.

Lake Malawi cichlid evolution along a benthic/limnetic axis

Divergence along a benthic to limnetic habitat axis is ubiquitous in aquatic systems. However, this type of habitat divergence has largely been examined in low diversity, high latitude lake systems. In this study, we examined the importance of benthic and limnetic divergence within the incredibly species-rich radiation of Lake Malawi cichlid fishes. Using novel phylogenetic reconstructions, we provided a series of hypotheses regarding the evolutionary relationships among 24 benthic and limnetic species that suggests divergence along this axis has occurred multiple times within Lake Malawi cichlids. Because pectoral fin morphology is often associated with divergence along this habitat axis in other fish groups, we investigated divergence in pectoral fin muscles in these benthic and limnetic cichlid species. We showed that the eight pectoral fin muscles and fin area generally tended to evolve in a tightly correlated manner in the Lake Malawi cichlids. Additionally, we found that larger pectoral fin muscles are strongly associated with the independent evolution of the benthic feeding habit across this group of fish. Evolutionary specialization along a benthic/limnetic axis has occurred multiple times within this tropical lake radiation and has produced repeated convergent matching between exploitation of water column habitats and locomotory morphology.

Enhancement of Hsp70 synthesis protects common carp, Cyprinus carpio L., against lethal ammonia toxicity

Exposure to TEX-OE®, a patented extract of the prickly pear cactus (Opuntia ficus indica) containing chaperone-stimulating factor, was shown to protect common carp, Cyprinus carpio L., fingerlings against acute ammonia stress. Survival was enhanced twofold from 50% to 95% after exposure to 5.92 mg L(-1) NH(3) , a level determined in the ammonia challenge bioassay as the 1-h LD50 concentration for this species. Survival of TEX-OE®-pre-exposed fish was enhanced by 20% over non-exposed controls during lethal ammonia challenge (14.21 mg L(-1)  NH(3) ). Increase in the levels of gill and muscle Hsp70 was evident in TEX-OE®-pre-exposed fish but not in the unexposed controls, indicating that application of TEX-OE® accelerated carp endogenous Hsp70 synthesis during ammonia perturbation. Protection against ammonia was correlated with Hsp70 accretion.

Heat shock proteins (chaperones) in fish and shellfish and their potential role in relation to fish health: a review

Heat shock proteins (HSPs), also known as stress proteins and extrinsic chaperones, are a suite of highly conserved proteins of varying molecular weight (c. 16-100 kDa) produced in all cellular organisms when they are exposed to stress. They develop following up-regulation of specific genes, whose transcription is mediated by the interaction of heat shock factors with heat shock elements in gene promoter regions. HSPs function as helper molecules or chaperones for all protein and lipid metabolic activities of the cell, and it is now recognized that the up-regulation in response to stress is universal to all cells and not restricted to heat stress. Thus, other stressors such as anoxia, ischaemia, toxins, protein degradation, hypoxia, acidosis and microbial damage will also lead to their up-regulation. They play a fundamental role in the regulation of normal protein synthesis within the cell. HSP families, such as HSP90 and HSP70, are critical to the folding and assembly of other cellular proteins and are also involved in regulation of kinetic partitioning between folding, translocation and aggregation within the cell. HSPs also have a wider role in relation to the function of the immune system, apoptosis and various facets of the inflammatory process. In aquatic animals, they have been shown to play an important role in health, in relation to the host response to environmental pollutants, to food toxins and in particular in the development of inflammation and the specific and non-specific immune responses to bacterial and viral infections in both finfish and shrimp. With the recent development of non-traumatic methods for enhancing HSP levels in fish and shrimp populations via heat, via provision of exogenous HSPs or by oral or water administration of HSP stimulants, they have also, in addition to the health effects, been demonstrated to be valuable in contributing to reducing trauma and physical stress in relation to husbandry events such as transportation and vaccination.

Cold machine perfusion versus static cold storage of kidneys donated after cardiac death: a UK multicenter randomized controlled trial

One third of deceased donor kidneys for transplantation in the UK are donated following cardiac death (DCD). Such kidneys have a high rate of delayed graft function (DGF) following transplantation. We conducted a multicenter, randomized controlled trial to determine whether kidney preservation using cold, pulsatile machine perfusion (MP) was superior to simple cold storage (CS) for DCD kidneys. One kidney from each DCD donor was randomly allocated to CS, the other to MP. A sequential trial design was used with the primary endpoint being DGF, defined as the necessity for dialysis within the first 7 days following transplant. The trial was stopped when data were available for 45 pairs of kidneys. There was no difference in the incidence of DGF between kidneys assigned to MP or CS (58% vs. 56%, respectively), in the context of an asystolic period of 15 min and median cold ischemic times of 13.9 h for MP and 14.3 h for CS kidneys. Renal function at 3 and 12 months was similar between groups, as was graft and patient survival. For kidneys from controlled DCD donors (with mean cold ischemic times around 14 h), MP offers no advantage over CS, which is cheaper and more straightforward.

Long-Term Cognitive Sequelae of Cerebral Malaria in Vietnam Veterans

The brains of fatal cases of cerebral malaria exhibit capillary occlusion, punctiform hemorrhages, and focal necrosis in subcortical white matter. Some studies have suggested that the brain pathology of survivors is similar to that of fatal cases. The purpose of this study was to investigate the hypothesis that cerebral malaria survivors would exhibit neuropsychological impairment due to the residual cerebral damage sustained from the infection. Vietnam veterans reporting a history of cerebral malaria were compared with a group of veterans with a history of combat-related injuries on standard neuropsychological tasks and on dichotic listening (DL). The cerebral malaria group performed worse on memory tasks and exhibited greater clinical impairments on DL, consistent with presumed disruption of subcortical white matter tracts.

Survey of healthcare-associated infection rates in a nursing home resident population

In this study we assessed the incidence and types of healthcare-associated infection (HCAI) in a nursing home resident population. The influences of home size, resident category, gender and age were also examined. Fifteen homes were recruited and infection rates recorded from 1 October 2006 to 2 December 2006. A rate of 6.04 infections/1000 bed days was recorded for the complete study. Infection rates for the four main categories of infection (number of infections/ 1000 bed days) were respiratory (2.52), urinary (1.87), skin and soft tissue (1.57) and gastrointestinal (0.41). Infection rates for small, medium and large homes were 4.64 (range 1.95—6.51), 5.9 (range 0.49—10.76) and 7.79 (range 5.79—9.39), respectively; however, statistical significance was not achieved ( p = 0.335). Results indicate that respiratory infection rates are higher in larger homes (4.08) than in small (1.88) or medium size homes (2.22). Urinary infection rates were similar in small (1.89), medium (1.88) and large (1.82) homes and skin and soft tissue infections were lower in small homes (0.87) but similar in medium (1.69) and large (1.90) homes. We found a statistically significant relationship between the type of infection acquired and both resident category ( p = 0.017) and gender ( p = 0.005); the relationship between type of infection and age did not reach statistical significance ( p = 0.346).

Hyperoxia Effects on Pulmonary Pressure: Volume Characteristics and Lavage Surfactant Phospholipid in the Newborn Rabbit

The effect of hyperoxia (greater than 95%) on surfactant phospholipid recovered by lavage and pulmonary pressure:volume characteristics was studied in rabbits exposed from birth through 4 days of life. Decreased surfactant phospholipid (microgram/mg dry lung weight) in the airways was observed as early as 6 h and persisted through 96 h of life in hyperoxia-exposed animals. The composition of lavage phospholipids and fatty acid profile of phosphatidylcholine was not altered by hyperoxia. Pressure:volume analysis revealed a decrease in maximum lung distensibility (V30, volume at 30 cm pressure) at 48 and 96 h and a decrease in inflation compliance (P30i, pressure on inflation to 30% V30) at 48 h of life in newborn pups exposed to hyperoxia. Pressure:volume changes in both male and female newborns were observed with hyperoxia exposure. However, only female pups exhibited a decrease in lavage phospholipid content as measured at 48 h. These data suggest that the newborn rabbit surfactant system is susceptible to oxygen toxicity. In addition to age-related differences, sex differences may exist with regard to susceptibility to hyperoxia. Subtle alterations in the surfactant system at this critical time of rapid lung development could have long lasting effects on lung function.

Investigation into the effect of an alcohol-based hand product on infection rate in a nursing home setting

The study assessed the impact on nursing home (NH) resident infection rates of providing staff with a personal alcohol-based hand product (ABHP) with and without training on its use.

Fifteen North Wales NHs were recruited and randomly allocated into one of three groups. All monitored infection rates throughout the study period of 18 weeks (Phase I [weeks 1—9], Phase II [weeks 11—19]). NHs used liquid soap and water for hand washing throughout the study. Groups B and C introduced interventions during week ten: Group B were provided with personal ABHPs without training on use; Group C personal ABHPs with standard training from the sponsoring hand hygiene company. Infection rates between groups and pre- and post-intervention were compared.

Infection rates (per 1,000 bed days) for Phase I vs. Phase II of the study were: Group A: 6.99 vs. 7.16; Group B: 6.08 vs. 3.46; and Group C: 5.04 vs. 6.78 respectively. Change in infection rates in Groups B and C pre- and post-intervention did not reach statistical significance, p = 0.097 and p = 0.072 respectively.

Comparison of rates in non-intervention Group A with the intervention groups indicated a significantly lower rate after the intervention in Group B ( p = 0.035) but not Group C ( p = 0.765).

Findings are limited due to sample size; introduction of personal ABHPs with training did not reduce infection rates. This conflicts with other studies examining education and improvement of hand hygiene compliance. However, infection rates fell in NHs not receiving training, possibly mediated through a sense of `ownership' of the intervention.

Needle-stick injuries in primary care in Wales

BACKGROUND

Accidental needle-stick injuries (NSIs) are a hazard for health-care workers and for the general public.

OBJECTIVES

To estimate the presentation rate of NSIs to general medical practices, their relation to practice characteristics, and review practice policies for managing NSIs.

METHOD

Descriptive study using logistic regression analysis.

RESULTS

Annual rates of 2.73 (95% CI 2.08, 3.50) occupational NSIs per 100 clinical practice staff and 2.14 (95% CI 1.39, 3.13) non-occupational NSIs per 100,000 practice population were recorded. Stepwise logistic regressions showed that chance of a practice reporting at least one occupational NSI in previous five years was best predicted by being a single-handed practice (decreased odds). In contrast, the chance of a practice reporting at least one non-occupational NSI was best predicted by being a rural practice (increased odds). About one in five practices possessed no written policy on managing NSIs. Stepwise logistic regressions showed that the chance of a practice owning a NSI policy was best predicted by being located in an LHB area with a coastline (increased odds).

CONCLUSION

NSIs are an important public health issue in Wales. We have tried to address the lack of guidance by developing new guidelines in Wales.

Pan-steatitis in farmed northern bluefin tuna, Thunnus thynnus (L.), in the eastern Adriatic

Clinical, gross and histopathological investigations were carried out into large-scale mortalities on eastern Mediterranean bluefin tuna, Thunnus thynnus (L.), farms. Fish showed only nervous signs and darkened colour. At post-mortem the liver was bronze coloured and the pyloric area waxy in consistency. There was no evidence of any other gross pathology. Histopathology showed severe hepatic necrosis and lipidosis. Peri-pancreatic lipoid tissue was heavily infiltrated with an inflammatory round cell infiltrate. Fish on all three farms had been fed on a North African pilchard diet rather than traditional local or Baltic species. Once the diet was modified, losses ceased. A diagnosis of pan-steatitis as seen in other farmed fish species, as well as in terrestrial animals, on particular fish-based diets was made, although the actual factor within the diet which induced the inflammatory effect is not known.

Spinal deformation in commercially cultured Atlantic salmon, Salmo salar L.: a clinical and radiological study

A clinical and radiographic study was carried out on 2016 randomly selected Atlantic salmon parr from six farms, which weighed between 55 and 100 g. In addition, 86 fish from six marine farms were similarly studied. Radiographically detectable vertebral lesions were found in 3.8-8.8% of the parr. The changes ranged from a single vertebra showing features, such as demineralization, increased density and slight loss of structure, to fish with multiple vertebrae affected by collapse, fusion and change in intervertebral space that could give rise to lordosis or kyphosis or abnormal vertebrae at several locations. The predominant location was the vertebral region V21-27, and rarely V44 caudad. The radiographic changes in seawater salmon mirrored those found in parr, but vertebrae V35 caudad were more frequently involved. Very few parr were found to have abnormal vertebrae in the peduncle area which suggests that the development of lesions at this location occurs de novo in the seawater phase, given that 'stumpy' fish are most frequent reported deformity at slaughter. It was concluded that minor vertebral change could be detected radiographically in many parr with no observable effect on external morphology. Whether such minor radiographic alteration would proceed to observable morphological change at slaughter weight is open to question.

The aetiology of spinal deformity in Atlantic salmon, Salmo salar L.: influence of genetic factors on the frequency and severity in freshwater stages

A radiographic study was carried out on 2-year groups of pre-smolt parr to detect the comparative frequency of vertebral change in a range of defined pedigreed families of high growth rate of Atlantic salmon, Salmo salar L., reared under identical conditions. The observed frequency of deformity was related to the observed deformity level in the seawater parental generation, and to a potentially uncontrolled environmental determinant, i.e. stripping date. High and low parental deformity groups of families were found to produce offspring that had very similar levels of radiographically detectable spinal deformities in the pre-smolt parr, suggesting no genetic link. With regard to stripping date, the overall incidence was nearly half that seen in the preceding year (8.7% cf 16.6%). However, a non-significant trend to fewer radiographic spinal deformities was seen in the later stripping period.

The aetiology of spinal deformity in Atlantic salmon, Salmo salar L.: influence of different commercial diets on the incidence and severity of the preclinical condition in salmon parr under two contrasting husbandry regimes

A large-scale trial of the effect of different commercial diets on the incidence of preclinical spinal deformation, as assessed by radiography, and the influence of two contrasting rearing systems was carried out. Two sets of three populations of Atlantic salmon, each of 20 000 first feeding fry of identical hatchery origin, created from equal numbers of eggs from 15 different families, were reared under commercial conditions on two different farms. Three commercial (closed formula) extruded fish meal-based diets were used in this study (diets A, B & C). Each diet was fed to one population of 20 000 fish at each site. Fish were fed a percentage of their body weight per day, with feeding rates set at commercial levels, based on water temperature, day length and fish biomass. Additional hand feeding was used to ensure satiation in all tanks. Fish in each tank were bulk-weighed and counted at the beginning and at 2-week intervals throughout the study. The fish were grown for 30 weeks. In addition, phosphorus (P) digestibility was evaluated by in-feed absorption testing in rainbow trout. The morphology of the radiographic lesions conformed to those described previously. Statistical analysis using multivariate regression analysis showed that date of sampling, site and diet were all statistically significant (P < 0.001) on univariable analysis. Farm A had significantly more affected fish than farm B (P < 0.001), which may have been attributable to variation in dissolved oxygen levels. The available dietary P levels were low in each diet. The number of fish affected in the group of fish being fed diet B was significantly lower than in the groups being fed diets A or C (P < 0.001). It appears most likely that the occurrence of preclinical radiographically apparent defects in parr which are believed to lead to the condition known as 'spinal deformity' is predominantly caused by a deficiency of available dietary P in first-feeding fry. The availability of dietary P may also vary considerably between diets formulated using different ingredients. Phytate-P associated with plant ingredients may affect the availability of P as well as other essential dietary nutrients. Additionally, diets for the production of salmonids in fresh water are currently formulated to keep P effluent to a minimum compatible with healthy spinal development. These various factors combine to make it crucial that small Atlantic salmon, especially first-feeding fry, are provided with carefully formulated diets fortified to an adequate level with a high quality source of available P.

Analysis of the incidence of infectious pancreatic necrosis mortality in pedigreed Atlantic salmon, Salmo salar L., populations

A total of 77,124 Atlantic salmon post-smolts, representing 197 full-sib families produced by 149 males and 197 females, experienced a field challenge from infectious pancreatic necrosis virus (IPNV), following transfer to three separate seawater sites. The first IPN mortality was observed 45 days after transfer, and the duration of the epidemic varied between 37 and 92 days among sites. Mortalities were traced to their parental families by PIT (Passive Integrated Transpondes) tag records and DNA genotyping. Full-sib family mean incidence of mortality was calculated for each family on each site. Heritabilities were estimated based on the heterogeneity of chi-square using incidence within half-sib families and the variance in incidence among full-sib families, both on the observed and underlying liability scale. The observed correlation among families across sites was used to estimate genetic correlations. The overall mortality rate was 10.8%, with only small differences between sites, ranging from 10.3% to 11.9%. Heritabilities on the liability scale were found to be moderate to strong, and ranged between 0.24 and 0.81, with a pooled estimate of 0.43, greater than is typically associated with disease traits. Genetic correlations among sites were all substantial, between 0.71 and 0.78, and indicated that a substantial component of the genetic variation displayed within sites was common to all. The results show that field challenges can yield very good genetic information on family differences in resistance, especially when replicated over sites, which may then be developed for use in selection for breeding strains of Atlantic salmon with greater resistance to IPN.

Maternal age in pregnancy and offspring blood pressure in childhood in the Avon Longitudinal Study of Parents and Children (ALSPAC)

Associations between maternal age in pregnancy and offspring blood pressure (BP) at age 7(1/2) were investigated in 7623 singletons from the Avon Longitudinal Study of Parents and Children (ALSPAC). In models adjusted for age and sex there was an inverse relationship between maternal age and BP in children: beta = -0.06 mmHg per year of maternal age (95% CI -0.10 to -0.01, P = 0.02) for systolic BP and beta = -0.04 (95% CI -0.07 to -0.01, P = 0.02) for diastolic BP. However, this association disappeared after adjustment for confounding factors: beta = -0.02 mmHg per year of maternal age (95% CI -0.07 to 0.04, P = 0.5) for systolic BP and beta = -0.03 (95% CI -0.07 to 0.01, P = 0.2) for diastolic BP. We conclude that there is no evidence of a relationship between maternal age in pregnancy and childhood BP in this contemporary birth cohort.

Exposure to school children as a risk factor in a community outbreak of hepatitis A in young adults: a case control study

To investigate risk factors during a community outbreak of hepatitis A we carried out a case- control study of 35 cases and 49 matched controls using an interviewer-administered questionnaire on clinical history, travel, household details including domestic toilet facilities, infectious contacts, and food history. Of 99 cases notified in the city during the outbreak year, 50 (51%) were young adults age 15-34 years. Hepatitis A infection was independently associated with household contact with a case (P=0.0005), and sharing a household with children in primary school (OR 3.4, 95% CI 1.2-9.5, P=0.008) with risk increasing with number of primary-school pupils in the household (chi(2) for linear trend 6.47, P=0.01). We concluded that in a population with a low prevalence of hepatitis A, adults who live in the same household as primary-school-age children are at increased risk of acquiring the infection during community outbreaks.

Infectious pancreatic necrosis in Atlantic salmon, Salmo salar L

A clinical and histopathological review was carried out of 21 outbreaks of acute infectious pancreatic necrosis (IPN) in Scottish Atlantic salmon, Salmo salar L., farms (13 marine and eight fresh water) during 1991-2004. A distinctive syndrome was evident in both post-smolts in sea water and fry in fresh water, where liver lesions, which had not previously been associated with IPN, became a consistent finding in addition to the more typical pancreatic and intestinal changes. Initial cases were described in post-smolts in Shetland, but by the end of the period of investigation this type of pathology had extended down the West coast of Scotland and into Ireland. Limited viral strain analysis suggested that similar strains were involved in both fresh water and sea water and that these differed from earlier isolates from rainbow trout, Oncorhynchus mykiss (Walbaum). In fresh water, recovered fish frequently developed a greatly distended intestine associated with accumulation of undigested food. In sea water, after the initial, often significant (50% or more), losses, there were many fish which failed to grow and became chronically emaciated and prone to sea louse infection. Although use of transfer diets containing immune enhancers and the selection of IPN resistant broodstock has reduced losses the disease remains a serious cause of economic loss.

The pathology of phosphorus deficiency in fish--a review

Phosphorus (P) is an essential component of fish diets. Its deficiency affects not only hard tissues, where it is responsible for rickets, leading to skeletal malformation, but also influences various aspects of intermediary metabolism, and thus growth and feed conversion. Therefore, optimizing the dietary inclusion level is critical at all times. As the aquaculture industry has expanded, so the effects of P in farm effluents, derived from metabolic and uneaten food sources, have also become recognized. Diets are increasingly formulated on a basis that will not only provide adequate P for fish needs, but also endeavour to ensure minimal acceptable P levels in effluents at the same time. Many variables influence P requirements and P availability in fish diets, so it is inadvisable to feed diets formulated to an assumed minimum dietary requirement level, irrespective of the advantages that such a formulation may provide to environmental impact.

Control of Salmincola californiensis (Copepoda: Lernaeapodidae) in rainbow trout, Oncorhynchus mykiss (Walbaum): a clinical and histopathological study

A stock of rainbow trout, Oncorhynchus mykiss, held at an experimental facility, was found to be heavily infested with the lernmaeapodid copepod Salmincola californiensis. The efficacy and effects of treatment were compared with ivermectin or manual removal of parasites as a means of control of S. californiensis. One group of fish was orally intubated with 0.2 mg ivermectin active ingredient kg-1 fish. A second treatment was administered after a further 14 days. In a second group of fish, parasites were manually removed from the gills using forceps. These fish were sampled for up to 21 days post-first removal of parasites. In the ivermectin-treated fish adult parasites became inactive and changed colour within 18 h of the initial treatment. Copepods began to disappear by day 3 post-treatment and by day 31 almost all embedded female parasites had disappeared. Gills were clinically normal apart from cavitation deformity resulting from parasite attachment. Post-ivermectin treatment, there was an increase in the number of eosinophilic granular cells surrounding the bulla of attached S. californiensis, but from day 31 post-treatment these were replaced by macrophages and epithelioid cells to form a necrotic focus. In manually picked fish there was extensive haemorrhage in the interlamellar spaces as a result of parasite removal. At sites of parasite removal tissue necrosis was minimal and healing was rapid. At the end of the sampling period the structure of the gill was improved. The use of oral dosage with ivermectin is an effective treatment for S. californiensis and could be particularly beneficial for use with endangered salmon broodstocks infested with the parasite.

Parents' attitude towards the second dose of measles, mumps and rubella vaccine: a case-control study

In response to media scares and subsequent falls in measles, mumps and rubella (MMR) vaccine uptake, a case-control study was conducted to identify factors associated with non-uptake of the second dose of the vaccine in children resident in North Wales. Subjects were selected from parents of children scheduled for the second dose between October and December 1997. Postal questionnaires were used to compare knowledge, attitudes and practice of non-acceptors (cases) and acceptors (controls). Of non-acceptors, 92.1% (95% CI 82.2-97.5%) stated that they would allow another child to have at least one dose of MMR, and 39.2% (95% CI 25.8-53.9%) both doses of MMR vaccine. Non-acceptors were more likely to report having obtained information from newspapers/television (OR 2.04, 95% CI 1.03-4.02) or from the general practitioner (OR 2.02, 95% CI 1.07-3.86) and to report having 'a lot' or 'some' influence from newspapers/television (OR 3.52, 95% CI 1.57-7.86). The 'combination of three vaccines in one jab' was identified as a worry by 55.1% (95% CI 40.2-69.3%) of non-acceptors and 38.5% (95% CI 30.6-46.9%) of acceptors. On this evidence, catch-up campaigns would be an effective way of increasing coverage; also health professionals need tools to enable them to communicate effectively in the face of ongoing scares.

Melano-macrophage centres and their role in fish pathology

Melano-macrophage centres, also known as macrophage aggregates, are distinctive groupings of pigment-containing cells within the tissues of heterothermic vertebrates. In fish they are normally located in the stroma of the haemopoietic tissue of the spleen and the kidney, although in amphibians and reptiles, and some fish, they are also found in the liver. They may also develop in association with chronic inflammatory lesions elsewhere in the body and during ovarian atresia. In higher teleosts, they often exist as complex discrete centres, containing lymphocytes and macrophages, and may be primitive analogues of the germinal centres of lymph nodes. Melano-macrophage centres usually contain a variety of pigments, including melanins, and these increase in range and volume in older fish or in the presence of cachectic disease. Melano-macrophage centres act as focal depositories for resistant intracellular bacteria, from which chronic infections may develop. Iron capture and storage in haemolytic diseases appears to be a primary function, but antigen trapping and presentation to lymphocytes, sequestration of products of cellular degradation and potentially toxic tissue materials, such as melanins, free radicals and catabolic breakdown products are among other functions that have been ascribed. Recent work suggests that they are a site of primary melanogenesis rather than mere storage. Melano-macrophage centres increase in size or frequency in conditions of environmental stress and have been suggested as reliable biomarkers for water quality in terms of both deoxygenation and iatragenic chemical pollution.

Functional analysis of iceA1, a CATG-recognizing restriction endonuclease gene in Helicobacter pylori

iceA1 in Helicobacter pylori is a homolog of nlaIIIR, which encodes the CATG-specific restriction endonuclease NlaIII in Neisseria lactamica. Analysis of iceA1 sequences from 49 H.pylori strains shows that a full-length NlaIII-like ORF is present in 10 strains, including CH4, but in other strains, including strain 60190, the ORFs are truncated due to a variety of mutations. Our goal was to determine whether iceA1 can encode a NlaIII-like endonuclease. Overexpression in Escherichia coli of iceA1 from CH4, but not from 60190, yielded NlaIII-like activity, indicating that the full-length iceA1 is a functional endonuclease gene. Repair of the iceA1 frameshift mutation in strain 60190 and its expression in E.coli yielded functional NlaIII-like activity. We conclude that iceA1 in CH4 is a functional restriction endonuclease gene, while iceA1 in 60190 is not, due to a frameshift mutation, but that its repair restores its restriction endonuclease activity.

An outbreak of Salmonella enteritidis phage type 34a infection in primary school children: the use of visual aids and food preferences to overcome recall bias in a case control study

Outbreaks of infectious intestinal disease are common in schools. Case control studies are useful in the investigation of infectious disease outbreaks but the time interval between illness and investigation can lead to recall bias, particularly in young children. We describe an outbreak of Salmonella enteritidis phage type 34a infection involving 54 clinical cases in two adjacent schools, and a novel approach to overcome recall bias. The likely dates of infection were identified from the epidemic curve. We created a visual display of the menu from those days and asked 9 cases and 18 matched controls to identify their food preferences from this display. Preference for chocolate mouse was significantly associated with illness (P = 0.006). The results of the case control study agreed with the findings of the environmental investigation. We believe our approach could be used in other circumstances, where subjects are young children or recall bias is a concern.

Theta bursts, closed head injury, and partial seizure-like symptoms: a retrospective study

The purpose of this retrospective, chart-review study was to provide additional information on the clinical correlates ofparoxysmal theta activity on EEG and to further examine the previously proposed relation (Varney, Hines, Bailey, & Roberts, 1992) between episodic symptoms in the context of prior closed-head injury and theta bursts. Allparticipants were veterans receiving their health care at a single, tertiary-care, Veterans Affairs medical center. Compared with patients with normal EEGs (comparison group, n = 30) and nonparoxysmal theta-delta slowing (comparison group, n = 30), consecutive patients with theta bursts (n = 38) were found to have significantly more episodic (ie., partial seizure-like) symptoms documented in their medical records. History of closed-head trauma was also associated with increased reporting of episodic symptoms across all three clinical groups. These findings suggest that, in the presence of theta bursts on EEG, clinicians may wish to interview systematicallyfor episodic, partial seizure-like phenomena, especially when paroxysmal theta activity occurs in the context of prior closed head injury.

AdoMet-dependent methylation, DNA methyltransferases and base flipping

Twenty AdoMet-dependent methyltransferases (MTases) have been characterized structurally by X-ray crystallography and NMR. These include seven DNA MTases, five RNA MTases, four protein MTases and four small molecule MTases acting on the carbon, oxygen or nitrogen atoms of their substrates. The MTases share a common core structure of a mixed seven-stranded beta-sheet (6 downward arrow 7 upward arrow 5 downward arrow 4 downward arrow 1 downward arrow 2 downward arrow 3 downward arrow) referred to as an 'AdoMet-dependent MTase fold', with the exception of a protein arginine MTase which contains a compact consensus fold lacking the antiparallel hairpin strands (6 downward arrow 7 upward arrow). The consensus fold is useful to identify hypothetical MTases during structural proteomics efforts on unannotated proteins. The same core structure works for very different classes of MTase including those that act on substrates differing in size from small molecules (catechol or glycine) to macromolecules (DNA, RNA and protein). DNA MTases use a 'base flipping' mechanism to deliver a specific base within a DNA molecule into a typically concave catalytic pocket. Base flipping involves rotation of backbone bonds in double-stranded DNA to expose an out-of-stack nucleotide, which can then be a substrate for an enzyme-catalyzed chemical reaction. The phenomenon is fully established for DNA MTases and for DNA base excision repair enzymes, and is likely to prove general for enzymes that require access to unpaired, mismatched or damaged nucleotides within base-paired regions in DNA and RNA. Several newly discovered MTase families in eukaryotes (DNA 5mC MTases and protein arginine and lysine MTases) offer new challenges in the MTase field.

Recombinant human DNA (cytosine-5) methyltransferase. III. Allosteric control, reaction order, and influence of plasmid topology and triplet repeat length on methylation of the fragile X CGG.CCG sequence

Steady-state kinetic analyses revealed that the methylation reaction of the human DNA (cytosine-5) methyltransferase 1 (DNMT1) is repressed by the N-terminal domain comprising the first 501 amino acids, and that repression is relieved when methylated DNA binds to this region. DNMT1 lacking the first 501 amino acids retains its preference for hemimethylated DNA. The methylation reaction proceeds by a sequential mechanism, and either substrate (S-adenosyl-l-methionine and unmethylated DNA) may be the first to bind to the active site. However, initial binding of S-adenosyl-l-methionine is preferred. The binding affinities of DNA for both the regulatory and the catalytic sites increase in the presence of methylated CpG dinucleotides and vary considerably (more than one hundred times) according to DNA sequence. DNA topology strongly influences the reaction rates, which increased with increasing negative superhelical tension. These kinetic data are consistent with the role of DNMT1 in maintaining the methylation patterns throughout development and suggest that the enzyme may be involved in the etiology of fragile X, a syndrome characterized by de novo methylation of a greatly expanded CGG.CCG triplet repeat sequence.

Comparative genomics of the restriction-modification systems in Helicobacter pylori

Helicobacter pylori is a Gram-negative bacterial pathogen with a small genome of 1.64-1.67 Mb. More than 20 putative DNA restriction-modification (R-M) systems, comprising more than 4% of the total genome, have been identified in the two completely sequenced H. pylori strains, 26695 and J99, based on sequence similarities. In this study, we have investigated the biochemical activities of 14 Type II R-M systems in H. pylori 26695. Less than 30% of the Type II R-M systems in 26695 are fully functional, similar to the results obtained from strain J99. Although nearly 90% of the R-M genes are shared by the two H. pylori strains, different sets of these R-M genes are functionally active in each strain. Interestingly, all strain-specific R-M genes are active, whereas most shared genes are inactive. This agrees with the notion that strain-specific genes have been acquired more recently through horizontal transfer from other bacteria and selected for function. Thus, they are less likely to be impaired by random mutations. Our results also show that H. pylori has extremely diversified R-M systems in different strains, and that the diversity may be maintained by constantly acquiring new R-M systems and by inactivating and deleting the old ones.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

REBASE--restriction enzymes and methylases

REBASE contains comprehensive information about restriction enzymes, DNA methylases and related proteins such as nicking enzymes, specificity subunits and control proteins. It contains published and unpublished references, recognition and cleavage sites, isoschizomers, commercial availability, methylation sensitivity, crystal data and sequence data. Homing endonucleases are also included. Most recently, extensive information about the methylation sensitivity of restriction enzymes has been added and a new feature contains complete analyses of the putative restriction systems in the sequenced bacterial and archaeal genomes. The data is distributed via email, ftp (ftp.neb.com) and the Web (http://rebase. neb.com).

Functional analysis of putative restriction-modification system genes in the Helicobacter pylori J99 genome

Helicobacter pylori is a gram-negative bacterium, which colonizes the gastric mucosa of humans and is implicated in a wide range of gastroduodenal diseases. The genomic sequences of two H.pylori strains, 26695 and J99, have been published recently. About two dozen potential restriction-modification (R-M) systems have been annotated in both genomes, which is far above the average number of R-M systems in other sequenced genomes. Here we describe a functional analysis of the 16 putative Type II R-M systems in the H. pylori J99 genome. To express potentially toxic endonuclease genes, a unique vector was constructed, which features repression and antisense transcription as dual control elements. To determine the methylation activities of putative DNA methyltransferases, we developed polyclonal antibodies able to detect DNA containing N6-methyladenine or N4-methylcytosine. We found that <30% of the potential Type II R-M systems in H.pylori J99 strain were fully functional, displaying both endonuclease and methyltransferase activities. Helicobacter pylori may maintain a variety of functional R-M systems, which are believed to be a primitive bacterial 'immune' system, by alternatively turning on/off a subset of numerous R-M systems.

Identification of type II restriction and modification systems in Helicobacter pylori reveals their substantial diversity among strains

A total of 22 type II restriction endonucleases with 18 distinct specificities have been identified in six Helicobacter pylori strains. Among these 18 specificities are three completely new endonucleases, Hpy178III, Hpy99I, and Hpy188I, that specifically cleave DNA at TCNNGA, CGWCG, and TCNGA sites, respectively. The set of endonucleases identified in each strain varies, but all have four- or five-base recognition sequences. Among 16 H. pylori strains, examination of the DNA modification status at the recognition sites of 15 restriction endonucleases reveals that each strain has a substantially different complement of type II modification systems. We conclude that the type II restriction-modification systems in H. pylori are highly diverse between strains, a unique characteristic of H. pylori. The diverse methylation status of H. pylori chromosomal DNA may serve as a new typing system to discriminate H. pylori isolates for epidemiological and clinical purposes. This study also demonstrates that H. pylori is a rich source of type II restriction endonucleases.

Comparison of wet combing with malathion for treatment of head lice in the UK: a pragmatic randomised controlled trial

BACKGROUND

Concern about the effectiveness and toxicity of insecticide lotions has led to promotion of mechanical methods to remove head lice. We compared the effectiveness of "bug-busting" (wet combing with a fine-toothed comb) and malathion lotion.

METHODS

We screened 4037 schoolchildren in two counties in Wales, UK (intermediate resistance to malathion). Of 167 found to have head lice, 81 (aged 3-14 years) were eligible to participate in a randomised controlled trial that compared mechanical removal of lice by a commercial kit every 3-4 days for 2 weeks with two applications of 0.5% malathion lotion 7 days apart; parents carried out both treatments. The outcome measure was the presence of live lice 7 days after the end of treatment. Analyses were by intention to treat.

FINDINGS

74 children completed the study and 72 were included in the analysis. The cure rate was 38% (12 of 32) for bug-busting and 78% (31 of 40) for malathion. Children assigned bug-busting were 2.8 (95% CI 1.5-5.2) times more likely than those assigned malathion to have lice at the end of treatment (p=0.0006).

INTERPRETATION

Malathion lotion was twice as effective as bug-busting, even in an area with intermediate resistance. Policies advocating bug-busting as first-line treatment for head lice in the general population are inappropriate. Assessment of the outcome of treatment 1-2 weeks after completion is essential for successful management. Only about 50% of participants complied fully with treatment, so future trials should be pragmatic in design, avoid false incentives, and study representative samples of children.

Data management in a longitudinal cross-cultural study

The Indianapolis-Ibadan Dementia Project compares the rates of dementia at two sites, one in the U.S.A. and one in Nigeria. This paper concentrates on the data management issues in this longitudinal cross-cultural study. Approximately 2500 elderly people were recruited at each site, and continue to be re-assessed every two years. All the data are collected on paper and then entered into a FoxPro relational database. Most of the data management, including data cleaning, is done in Indianapolis. The design of the data collection forms is particularly important in a cross-cultural study, with the questions and the coding of responses clear and simple. Since Nigeria and the U.S.A. have different levels of technological development, the computer hardware and software were chosen to be suitable for use at either site. Exchange visits have been needed to address data management issues and resolve unexpected problems. The data management on cross-cultural studies can be handled successfully, given careful planning.

Purification of the novel endonuclease, Hpy188I, and cloning of its restriction-modification genes reveal evidence of its horizontal transfer to the Helicobacter pylori genome

We have isolated a novel restriction endonuclease, Hpy188I, from Helicobacter pylori strain J188. Hpy188I recognizes the unique sequence, TCNGA, and cleaves the DNA between nucleotides N and G in its recognition sequence to generate a one-base 3' overhang. Cloning and sequence analysis of the Hpy188I modification gene in strain J188 reveal that hpy188IM has a 1299-base pair (bp) open reading frame (ORF) encoding a 432-amino acid product. The predicted protein sequence of M.Hpy188I contains conserved motifs typical of aminomethyltransferases, and Western blotting indicates that it is an N-6 adenine methyltransferase. Downstream of hpy188IM is a 513-bp ORF encoding a 170-amino acid product, that has a 41-bp overlap with hpy188IM. The predicted protein sequence from this ORF matches the amino acid sequence obtained from purified Hpy188I, indicating that it encodes the endonuclease. The Hpy188I R-M genes are not present in either strain of H. pylori that has been completely sequenced but are found in two of 11 H. pylori strains tested. The significantly lower G + C content of the Hpy188I R-M genes implies that they have been introduced relatively recently during the evolution of the H. pylori genome.