1045 Summarising the Reporting of Regulatory Procedures in Robotic Cholecystectomy: A Systematic Review and Narrative Synthesis

Introduction

Robotic cholecystectomy (RC) represents the most recent innovation in the management of gallstones. Whilst RC is becoming increasingly widespread, the evidence base surrounding its introduction has not been characterised. When evaluating innovative surgical techniques, adherence to regulatory and governance procedures is essential in maintaining patient safety. This study aims to appraise the reporting of studies of RC, focussing on regulatory procedures.

Method

Systematic searches identified all published studies reporting RC. Data collection was based on the IDEAL (Idea, Development, Exploration, Assessment, Long-term follow-up) framework, and included general study characteristics, governance approvals, trial registration, study funding, conflicts of interests, and information communicated to patients.

Results

Systematic searches identified 1425 abstracts. Of the 90 full-text papers included, only three were randomised controlled trials. The majority (71%) were single-centre studies. Conflicts of interest were common, with 11 (12%) studies funded by the robot manufacturer, and 23 (26%) reporting conflicts related to authors. Ethical approval was confirmed in 51 (57%) studies; four reported prior registration with a register. Only forty-two studies (47%) documented obtaining patient consent for study participation. Only four documented discussions regarding the innovative nature of RC. In ten, modifications to the robot or technique were described, but it was not apparent if patients were informed of these.

Conclusions

This comprehensive review highlights multiple deficiencies in the reporting of regulatory procedures in the evaluation of RC. Improved reporting is required in studies of RC to ensure transparency, interpretability, and the safe, evidence-based adoption of new technologies into clinical practice.

1096 Robot-Assisted Minimally Invasive Oesophagectomy: Comparing the Geography of Research Publication with The Global Burden of Disease

Introduction

Robot-assisted minimally invasive oesophagectomy (RAMIE) is increasingly used in the management of oesophageal tumours. It is unclear if there is equitable access to this innovative technique worldwide, specifically in areas of greatest need. This study aimed to map the geographic distribution of publications on RAMIE and compare this to global disease burden.

Method

Systematic searches identified all studies of RAMIE from inception to 2020. The country of origin of each study was identified. The incidence and age standardised rate (ASR) of oesophageal cancer for each country was obtained from The Global Cancer Observatory (GLOBOCAN) database. World Bank classifications of countries by income level were obtained.

Results

A total of 103 studies were identified. The majority (81%) were published in high-income countries, 15% in upper-middle, and 5% in lower-middle income countries. Thirty-four were published in the USA, the country with the fifth-highest incidence of oesophageal cancer worldwide, but 90th by ASR. The greatest incidence was in China (54% of global incidence) but was the source of only 15% of studies. Of the ten countries with the highest incidence, five were represented in published studies, in comparison to one of the top 10 by ASR.

Conclusions

There is evident disparity in the geographical distribution of published studies of RAMIE. This disparity may represent unequal access to surgical technologies, or a lack of evaluation of the technology in different healthcare settings. This may impact the generalisability of research findings. Equitable access to novel surgical technologies is ethical and can help address global disease burden.

558 Summarising the Reporting of Outcomes in Studies of Robot Assisted Cholecystectomy: A Systematic Review

Background

Robot-assisted cholecystectomy (RC) has seen increasing adoption into clinical practice despite a lack of evidence to demonstrate superiority over conventional methods. Consistency in outcome selection, definition and reporting between studies is required for effective evidence synthesis and to minimise research waste. The aim of this study was to conduct an in-depth analysis of the outcomes reported in studies of RC. This work will inform the need for a core outcome set (COS).

Method

Systematic searches identified all published studies reporting RC, from inception to February 2020. Outcomes reported in each manuscript were recorded verbatim and categorised into domains. All outcomes were coded in duplicate. Where reported, the follow up period of each study was documented.

Results

Of 1425 abstracts screened, ninety studies met the criteria for inclusion. A total of 878 outcomes were reported. Each study included a median of 8 outcomes (range 3-26). Outcome selection was heterogeneous, with those relating to technical/operative factors (n = 383, 88 studies), complications (n = 245, 81 studies) and health economics (n = 139, 72 studies) used most frequently. No single outcome, or outcome domain, was reported in all studies. Only 30 studies reported a follow-up period, which ranged from 14 days to 46 months. In thirteen, the follow-up was for less than or equal to one month.

Conclusions

We identified significant heterogeneity in the selection and reporting of outcomes in studies of RC and support calls for standardisation and development of a COS.

858 Transoral Robotic Surgery: Comparing the Geography of Research Publications with The Global Burden of Disease

Introduction

Transoral robotic surgery (TORS) is increasingly used for the resection of oropharyngeal tumours. It is unclear if there is equitable access to this innovative technique worldwide, specifically in areas of greatest need. This study aimed to map the geographic distribution of publications on TORS and compare this to global disease burden.

Method

Systematic searches identified all studies of TORS from inception to 2018. The country of origin of each study was identified. The incidence and age standardised rate (ASR) of oropharyngeal cancer for each country was obtained from The Global Cancer Observatory (GLOBOCAN) database. World Bank classifications of countries by income level were obtained.

Results

A total of 132 studies were identified. The majority (96%) were published in high-income countries, 2% in lower-middle, and 2% in upper-middle income countries. Eighty-nine were published in the USA, the country with the second-highest incidence of oropharyngeal cancer worldwide (13% of total), but 20th by ASR. The greatest incidence was in India (21%), however this was the source of only 2% of studies. Of the ten countries with the highest incidence, eight were represented in published studies, in comparison to four of the top 10 by ASR.

Conclusions

There is evident disparity in the geographical distribution of published studies of TORS. This disparity may represent unequal access to surgical technologies, or a lack of evaluation of the technology in different healthcare settings. This may impact the generalisability of research findings. Equitable access to novel surgical technologies is ethical and can help address global disease burden.

Structural basis for the O-acetyltransferase function of the extracytoplasmic domain of OatA from Staphylococcus aureus

Many bacteria possess enzymes that modify the essential cell-wall polymer peptidoglycan by O-acetylation. This modification occurs in numerous Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, a common cause of human infections. O-Acetylation of peptidoglycan protects bacteria from the lytic activity of lysozyme, a mammalian innate immune enzyme, and as such is important for bacterial virulence. The O-acetylating enzyme in Gram-positive bacteria, O-acetyltransferase A (OatA), is a two-domain protein consisting of an N-terminal integral membrane domain and a C-terminal extracytoplasmic domain. Here, we present the X-ray crystal structure at 1.71 Å resolution and the biochemical characterization of the C-terminal domain of S. aureus OatA. The structure revealed that this OatA domain adopts an SGNH-hydrolase fold and possesses a canonical catalytic triad. Site-specific replacement of active-site amino acids revealed the presence of a water-coordinating aspartate residue that limits esterase activity. This residue, although conserved in staphyloccocal OatA and most other homologs, is not present in the previously characterized streptococcal OatA. These results provide insights into the mechanism of acetyl transfer in the SGNH/GDSL hydrolase family and highlight important evolutionary differences between homologous OatA enzymes. Furthermore, this study enhances our understanding of PG O-acetyltransferases, which could guide the development of novel antibacterial drugs to combat infections with multidrug-resistant bacterial pathogens.

Development of a High Throughput Screen for the Identification of Inhibitors of Peptidoglycan O-Acetyltransferases, New Potential Antibacterial Targets

The O-acetylation of peptidoglycan occurs in many Gram-negative and most Gram-positive pathogens and this modification to the essential wall polymer controls the lytic activity of the autolysins, particularly the lytic transglycosylases, and inhibits that of the lysozymes of innate immunity systems. As such, the peptidoglycan O-acetyltransferases PatA/B and OatA are recognized as virulence factors. In this study, we present the high throughput screening of small compound libraries to identify the first known inhibitors of these enzymes. The fluorometric screening assay developed involved monitoring the respective O-acetyltransferases as esterases using 4-methylumbelliferylacetate as substrate. Pilot screens of 3921 compounds validated the usefulness of the HTS protocol. A number of potential inhibitors were identified amongst a total of 145,000 low molecular-weight compounds, some of which were common to both enzymes, while others were unique to each. After eliminating a number of false positives in secondary screens, dose response curves confirmed the apparent specificity of a benzothiazolyl-pyrazolo-pyridine as an inhibitor of Neisseria gonorrhoeae PatB, and several coumarin-based compounds as inhibitors of both this PatB and OatA from Staphylococcus aureus. The benzothiazolyl-pyrazolo-pyridine was determined to be a non-competitive inhibitor of PatB with a Ki of 126 µM. At 177 µg/mL and close to its solubility limit, this compound caused a 90% reduction in growth of N. gonorrhoeae, while growth of Escherichia coli, a bacterium that lacks PatB and, hence, does not produce O-acetylated peptidoglycan, was unaffected. These data provide preliminary proof of concept that peptidoglycan O-acetyltransferases would serve as useful antibacterial targets.

Effects of defined gut microbial ecosystem components on virulence determinants of Clostridioides difficile

Many cases of Clostridioides difficile infection (CDI) are poorly responsive to standard antibiotic treatment strategies, and often patients suffer from recurrent infections characterized by severe diarrhea. Our group previously reported the successful cure of two patients with recurrent CDI using a standardized stool-derived microbial ecosystem therapeutic (MET-1). Using an in vitro model of the distal gut to support bacterial communities, we characterized the metabolite profiles of two defined microbial ecosystems derived from healthy donor stool (DEC58, and a subset community, MET-1), as well as an ecosystem representative of a dysbiotic state (ciprofloxacin-treated DEC58). The growth and virulence determinants of two C. difficile strains were then assessed in response to components derived from the ecosystems. CD186 (ribotype 027) and CD973 (ribotype 078) growth was decreased upon treatment with DEC58 metabolites compared to ciprofloxacin-treated DEC58 metabolites. Furthermore, CD186 TcdA and TcdB secretion was increased following treatment with ciprofloxacin-treated DEC58 spent medium compared to DEC58 spent medium alone. The net metabolic output of C. difficile was also modulated in response to spent media from defined microbial ecosystems, although several metabolite levels were divergent across the two strains examined. Further investigation of these antagonistic properties will guide the development of microbiota-based therapeutics for CDI.

Mechanistic Pathways for Peptidoglycan O-Acetylation and De-O-Acetylation

The post-synthetic O-acetylation of the essential component of bacterial cell walls, peptidoglycan (PG), is performed by many pathogenic bacteria to help them evade the lytic action of innate immunity responses. Occurring at the C-6 hydroxyl of N-acetylmuramoyl residues, this modification to the glycan backbone of PG sterically blocks the activity of lysozymes. As such, the enzyme responsible for this modification in Gram-positive bacteria is recognized as a virulence factor. With Gram-negative bacteria, the O-acetylation of PG provides a means of control of their autolysins at the substrate level. In this review, we discuss the pathways for PG O-acetylation and de-O-acetylation and the structure and function relationship of the O-acetyltransferases and O-acetylesterases that catalyze these reactions. The current understanding of their mechanisms of action is presented and the prospects of targeting these systems for the development of novel therapeutics are explored.

Estimation of tile drainage contribution to streamflow and nutrient loads at the watershed scale based on continuously monitored data

Nitrogen losses from artificially drained watersheds degrade water quality at local and regional scales. In this study, we used an end-member mixing analysis (EMMA) together with high temporal resolution water quality and streamflow data collected in the 122 km² Otter Creek watershed located in northeast Iowa. We estimated the contribution of three end-members (groundwater, tile drainage, and quick flow) to streamflow and nitrogen loads and tested several combinations of possible nitrate concentrations for the end-members. Results indicated that subsurface tile drainage is responsible for at least 50% of the watershed nitrogen load between April 15 and November 1, 2015. Tiles delivered up to 80% of the stream N load while providing only 15-43% of the streamflow, whereas quick flows only marginally contributed to N loading. Data collected offer guidance about areas of the watershed that should be targeted for nitrogen export mitigation strategies.

The first confirmed cases of full albinism in rajid species

Three albino skate specimens (Rajidae) were captured from the North Sea and English Channel between 2008 and 2011. Using DNA barcoding (COI gene) and morphometric analyses, species were identified as a spotted ray Raja montagui, a blonde ray Raja brachyura and a thornback ray Raja clavata. This finding represents the first record of full albinism (a lack of skin and retinal pigmentation) in rajid species.

Low genetic diversity in a snail intermediate host (Biomphalaria pfeifferi Krass, 1848) and schistosomiasis transmission in the Senegal River Basin

Population genetic perturbations of intermediate hosts, often a consequence of human pressure on environmental resources, can precipitate unexpectedly severe disease outbreaks. Such disturbances are set to become increasingly common following range changes concomitant with climate shifts, dwindling natural resources and major infrastructure changes such as hydroprojects. Construction of the Diama dam in the Senegal River Basin (SRB) reduced river salinity, enabling the freshwater snail intermediate host Biomphalaria pfeifferi to rapidly expand its distribution. A serious public health problem ensued, with an epidemic of intestinal schistosomiasis occurring in the previously schistosome-free Richard-Toll region within 2 years. The current study aimed to assess the population variability of B. pfeifferi in the SRB, and speculate upon its subsequent impact on host-parasite interactions following such engineered ecological change. Genetic variation at nine polymorphic microsatellite loci revealed little population differentiation in SRB snails compared with those from natural habitats in Zimbabwe, where Schistosoma mansoni transmission is much lower. 'Open' SRB habitats are associated with greater water contact, smaller population sizes and less genetic diversity, with sites downstream of Richard-Toll showing greater inter- and intrapopulation variation, concomitant with less frequent human contact. These observations may be explained by rapid expansion into pristine habitat selecting for high fecundity genotypes at the expense of schistosome resistance, presenting S. mansoni with genetically homogenous highly fecund susceptible populations around the focal point, promoting development of a highly compatible host-parasite relationship. Longitudinal study of such systems may prove important in predicting public health risks engendered by future environmental engineering projects.

Size-dependent growth of individual Atlantic salmon Salmo salar alevins from hatch to first feeding

Variation in egg size, hatch timing and size at hatch, and their influence on individual growth rates of Atlantic salmon Salmo salar alevins up to first feeding were examined in pure strain and hybrid crosses of fish from Scotland and Canada. At the intra-female, intra-cross type and inter-cross type levels, specific growth rates prior to first feed were strongly size dependent, with smaller and later hatching alevins growing significantly faster. The magnitude of this size-dependent growth was greatest in the hybrid crosses. This resulted in a 40% reduction in the coefficient of variation (c.v.) in alevin size from post-hatch to first feeding at the intra-female level, and a reduction of both intra- and inter-cross differences in alevin sizes in the same period.

Leaf shape linked to photosynthetic rates and temperature optima in South African Pelargonium species

The thermal response of gas exchange varies among plant species and with growth conditions. Plants from hot dry climates generally reach maximal photosynthetic rates at higher temperatures than species from temperate climates. Likewise, species in these environments are predicted to have small leaves with more-dissected shapes. We compared eight species of Pelargonium (Geraniaceae) selected as phylogenetically independent contrasts on leaf shape to determine whether: (1) the species showed plasticity in thermal response of gas exchange when grown under different water and temperature regimes, (2) there were differences among more- and less-dissected leafed species in trait means or plasticity, and (3) whether climatic variables were correlated with the responses. We found that a higher growth temperature led to higher optimal photosynthetic temperatures, at a cost to photosynthetic capacity. Optimal temperatures for photosynthesis were greater than the highest growth temperature regime. Stomatal conductance responded to growth water regime but not growth temperature, whereas transpiration increased and water use efficiency (WUE) decreased at the higher growth temperature. Strikingly, species with more-dissected leaves had higher rates of carbon gain and water loss for a given growth condition than those with less-dissected leaves. Species from lower latitudes and lower rainfall tended to have higher photosynthetic maxima and conductance, but leaf dissection did not correlate with climatic variables. Our results suggest that the combination of dissected leaves, higher photosynthetic rates, and relatively low WUE may have evolved as a strategy to optimize water delivery and carbon gain during short-lived periods of high soil moisture. Higher thermal optima, in conjunction with leaf dissection, may reflect selection pressure to protect photosynthetic machinery against excessive leaf temperatures when stomata close in response to water stress.

The effects of lubrication on the temperature rise and surface finish of amalgam and composite resin

It was thought that when finishing and polishing direct filling materials lubrication would affect the surface roughness and temperature rise in samples of amalgam and composite.

OBJECT

Previous work by the authors has shown that there is an optimum load, speed and time that produced the smoothest surface when finishing amalgam and composite resin using each of four grades of a disc system. This work was undertaken to examine the effects on temperature rise in samples of amalgam and composite resin of finishing dry compared to finishing with different lubricants. The experiments all used these optimum loads, speeds and times. It also compares the surface finish produced using different lubricants.

MATERIALS AND METHODS

A high copper amalgam and a hybrid composite resin were finished using the four grades of abrasive discs. Samples produced were 25 mm long by 6 mm wide by 2 mm deep. A thermocouple was inserted 1 mm into the base of the samples. The thermocouple was connected via an electronic thermometer to a computer that permitted the display and recording of temperature against time. After roughening, the samples were finished and polished in a specially constructed jig that mimicked oral finishing. The pre-determined optimum loads, speeds and times were used sequentially for each of the four grades of disc. Five samples were tested for each method of finishing. Firstly, run dry, then in turn lubricated with water, walnut oil and petroleum jelly. After the use of each abrasive disc the surface roughness was measured. One of the five samples was selected at random and prepared for examination in the scanning electron microscope. All results were subjected to non-parametric statistically analyses.

RESULTS

With both materials the temperature rise was greatest when run dry, followed by petroleum jelly, walnut oil and the least was when lubricated with water. With these two materials the surface roughness correlates negatively with the temperature rise. The smoothest surface being achieved when finished dry.

CONCLUSIONS

To obtain the smoothest surface finish amalgam and composite should be finished dry but further work is needed to assess the effect of the temperature rise found in the materials on the pulp.

The effects of lubrication on the temperature rise and surface finish of glass-ionomer cements

OBJECT

Previous work [Jones CS. Factors influencing the finishing of direct filling materials. PhD Thesis, University of London; 2002] has shown that there is an optimum load, speed and time that produced the smoothest surface when finishing glass-ionomer cement using each of four grades of a disc system. This study looks at the effects of lubrication on the temperature produced in samples of GIC when finished dry and with different lubricants using these optimal loads, speeds and times. It also compares the surface finish produced using different lubricants.

MATERIALS AND METHODS

A thermocouple connected so that it permitted the display and recording of temperature against time was inserted 1mm into the base of samples of a glass-ionomer cement. The samples were finished and polished using each of the grades of a disc system in a specially constructed jig that mimicked oral finishing. After roughening, the pre-determined optimum loads, speeds and times were used sequentially for each of the four grades of disc. Five samples were tested for each method of finishing. Firstly run dry, then in turn lubricated with water, walnut oil and petroleum jelly. After the use of each abrasive disc the surface roughness was measured using a profilometer. One of the five samples was selected at random and prepared for examination in the scanning electron microscope. All results were subjected to non-parametric statistically analyses.

RESULTS

Walnut oil and petroleum jelly produced significant temperature increases compared to both dry and with water finishing. Lubricated with water significantly reduced the temperature rise compared to dry. The Ra values of 0.5 microm was obtained for the coarse and a value of 0.3 microm for the medium discs run without lubrication. With lubrication the Ra increased although there was little difference between the lubricants. However the photomicrographs showed that walnut oil and petroleum jelly caused gross morphological changes indicating major surface destruction.

CONCLUSIONS

The practice of finishing GICs using petroleum jelly or similar lubricant appears to be detrimental. Further experimental work needs to be done to advise practitioners on finishing GICs to produce the smoothest surface possible.

Effect of dietary α-lipoic acid on growth, body composition, muscle pH, and AMP-activated protein kinase phosphorylation in mice1

The effects of alpha-lipoic acid (ALA) on the growth, body composition, postmortem AMP-activated protein kinase (AMPK) activation, and 24-h muscle pH were investigated. Thirty male C57BL/6J mice were fed diets containing 0, 0.5, or 1.0% ALA (DM basis). At the end of the 3-wk feeding trial, carcass weights decreased (P < 0.05) 14 and 30% for mice fed 0.5 and 1.0% ALA, respectively, compared with the 0% group, with decreases in BW as the levels of dietary ALA increased. This change in carcass weight occurred because carcass fat content for mice receiving 0.5 and 1.0% ALA was 7.32 and 8.09% lower (P < 0.05), respectively, than for the 0% ALA treatment, and because gonadal fat decreased (P < 0.05) 85% in mice fed 1.0% ALA compared with those fed 0% ALA. Dietary ALA caused a slight increase (P < 0.05) in carcass moisture content, with no (P = 0.07) effect on protein and ash content. Furthermore, ALA supplement decreased (P < 0.05) ADFI (DM basis) from 4.3 g/d for 0% ALA-fed mice to 3.4 g/d for 1.0% ALA-fed mice. At 20 min postmortem, pH was greater (P < 0.05) in muscle of mice fed 1.0% ALA than in muscle of mice fed 0% ALA. Ultimate (24-h) pH values differed (P < 0.05) among treatments, and mean values were 5.83, 6.08, and 6.29 for 0, 0.5, and 1.0% ALA, respectively. Phosphorylation of AMPK alpha subunit at Thr172, an indicator of AMPK activation, was decreased (P < 0.05) in muscle of ALA-treated mice at 20 min postmortem. Because AMPK has a crucial role in the control of glycolysis, the reduction in AMPK activation decreases glycolysis, and thereby increases the ultimate pH of postmortem muscle. In summary, dietary ALA supplement can decrease fat accumulation in mice, and because ALA increased muscle pH at 20 min and 24 h postmortem, these results suggest that dietary ALA supplementation might decrease carcass fatness and prevent the development of PSE pork and poultry. However, further research is required to test the effects of ALA in swine and poultry.

Laboratory study of the loads, speeds and times to finish and polish direct restorative materials

This study investigated the loads, speeds and times required to achieve the smoothest surface on samples of amalgam, composite resin and glass-ionomer cement using the four grades of a disc polishing system. The tests were conducted on a specially constructed jig. The restorations were abraded with the appropriate disc using a range of loads, speeds and times based on a previous practitioner study. The surface roughness of each material was measured before and after abrading. The load was varied first, followed by speed and finally time. Photomicrographs were taken of a sample finished at the optimum load, speed and time and of loads above and below the optimum that produced the smoothest surface finish. In addition the fractured edge of a sample finished at the optimum values was examined. There was an optimum load, speed and time that produced the smoothest surface for each restorative material. For amalgam and composite the surface roughness value decreased as the discs became finer. There was a reduction in the roughness value for glass-ionomer cement using the two roughest discs. The values obtained were substantially in contrast from the earlier practitioner study. There were specific values for load, speed and time that produced a smoother surface for each material.

Breeding system and demography shape population genetic structure across ecological and climatic zones in the African freshwater snail, Bulinus forskalii (Gastropoda, Pulmonata), intermediate host for schistosomes

The role of breeding system and population bottlenecks in shaping the distribution of neutral genetic variation among populations inhabiting patchily distributed, ephemeral water bodies was examined for the hermaphroditic freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma guineensis. Levels of genetic variation at 11 microsatellite loci were assessed for 600 individuals sampled from 19 populations that span three ecological and climatic zones (ecozones) in Cameroon, West Africa. Significant heterozygote deficiencies and linkage disequilibria indicated very high selfing rates in these populations. Despite this and the large genetic differentiation detected between populations, high levels of genetic variation were harboured within these populations. The high level of gene flow inferred from assignment tests may be responsible for this pattern. Indeed, metapopulation dynamics, including high levels of gene flow as well as extinction/contraction and recolonization events, are invoked to account for the observed population structuring, which was not a consequence of isolation-by-distance. Because B. forskalii populations inhabiting the northern, Sahelian area are subject to more pronounced annual cycles of drought and flood than the southern equatorial ones, they were expected to be subject to population bottlenecks of increased frequency and severity and, therefore, show reduced genetic variability and elevated population differentiation. Contrary to predictions, the populations inhabiting the most northerly ecozone exhibited higher genetic diversity and lower genetic differentiation than those in the most southerly one, suggesting that elevated gene flow in this region is counteracting genetic drift.

The advantages and disadvantages of running a clinical trial in general practices

This paper reviews the experiences encountered in running a clinical trial on the use of a metal reinforced glass-ionomer cement in general dental practices. The practitioners were asked to place both the test material and amalgam in the same patient and to take impressions both at placement and at three recall intervals. Subsequently plaster casts were produced from these impressions. These were then assessed by three independent observers to provide evaluation of the relative wear of the two restoratives under evaluation. A commercial laboratory manufactured the models on which the three independent observers carried out the assessment of wear. Although the practitioners indicated they would be able to provide the number of restorations required in a relatively short period these expected numbers were never achieved. Despite recruitment of additional participants the trial never did achieve the number of restorations required. The performance of the metal reinforced glass ionomer appeared to vary dependent on the practitioner placing the filling. Questioning of the participants found that some participants were finishing the material using a method specifically contraindicated in the protocol for the trial, the directions supplied with the product, and in briefing sessions held prior to the trial. This implies that there can be major problems in undertaking clinical trials of this nature in the general dental service and has serious clinical implications for those contemplating this type of evaluation and for manufacturers introducing new products.

The in vivo perception of roughness of restorations

OBJECTIVE

To determine a threshold of detection value for surface roughness of restorations by patients using their tongue.

METHOD

Samples of composite resin were finished with differing grades of abrasive. The surface roughness (Ra) was measured and representative scanning electro-micrographs taken. These were compared with labial enamel. Twenty-five volunteers were asked to rank them in order of perceived roughness using the tip of their tongue.

RESULTS

These showed that the 60% of volunteers were able to rank the specimens correctly, and were able to distinguish differences in roughness values from between 0.25 and 0.50 microm. This range encompasses that of natural enamel.

CONCLUSIONS

The subjects were able to distinguish lower roughness values than have previously been reported. It is concluded that when finishing restorations the surface should have a maximum roughness 0.50 microm if it is not to be detected by the patient.

The expression of immune-regulatory genes in rainbow trout,Oncorhynchus mykiss, during a natural outbreak of proliferative kidney disease (PKD)

Proliferative kidney disease (PKD) is a parasitic infection of salmonid fish characterized by an apparently abnormal immune response to the presence of the myxozoan parasite,Tetracapsuloides bryosalmonae. In order to examine the nature of the immune response at the molecular level, the expression of a range of immune regulatory genes, including cytokines and cyclooxygenase (COX)-2 was examined in naive unexposed fish and in naive fish exposed to parasite-infected water at three points during the course of a natural outbreak of PKD. Since fish with advanced PKD pathology generally exhibit increased susceptibility to secondary infections which is typical of stress/cortisol-mediated immune suppression, a further aim of this work was to examinein vitrothe influence of the glucocorticoid cortisol on the bacterial lipopolysaccharide (LPS)-induced expression of the trout cytokine genes studied. Two weeks after the initial sampling, naive exposed fish showed a specific profile of up-regulated tumor necrosis factor (TNF)-α2, COX-2 and, to a lesser extent, transforming growth factor (TGF)-β1 expression. As the disease pathology increased, TNF-α2 and COX-2 expression returned to normal levels. Stress levels of cortisol suppressed the LPS inducibility of pro-inflammatory cytokine genes, although TGF-β1 and TNF-α2 appeared to be refractory. These data demonstrate that specific immune responses at the molecular level are affected during PKD infection, with the cortisol suppression of cytokine expressionin vitroproviding a possible link to PKD-mediated cytokine down-regulation and immune suppression.

Measurement of IgG antibodies to Chlamydia trachomatis by commercial enzyme immunoassays and immunofluorescence in sera from pregnant women and patients with infertility, pelvic inflammatory disease, ectopic pregnancy, and laboratory diagnosed Chlamydia psittaci/Chlamydia pneumoniae infection

BACKGROUND

Screening for Chlamydia trachomatis specific antibodies is valuable in diagnosing asymptomatic pelvic inflammatory disease (PID) and tubal damage following repeated episodes of PID. The assays in current use are unsuitable for screening large numbers of samples so there is a need to develop more suitable assays.

AIMS

To compare the performance of several commercial C trachomatis enzyme immunoassays (EIAs) (SeroCT, C tracho(pep), Medac p-EIA, Vircell and Labsystems C trachomatis IgG EIAs) using major outer membrane protein (MOMP), an inactivated organism EIA (Genzyme Virotech EIA), and a genus specific EIA (Platelia Chlamydia IgG) with the whole cell inclusion immunofluorescence (WIF) assay. In addition, to adapt, using time resolved fluorescence technology, the assay showing the highest correlation with WIF.

METHODS

Ninety sera from patients presenting with ectopic pregnancies, 187 sera from those with a variety of types of infertility, 33 sera from cases of PID where a fourfold rise in WIF titre occurred, and 90 sera from antenatal clinic attenders were tested. A panel of 36 sera from laboratory diagnosed cases of Chlamydia psittaci/Chlamydia pneumoniae infection was also tested.

RESULTS

The Genzyme Virotech EIA showed the highest rank correlation coefficient (0.82) with WIF, particularly at high WIF titres. The MOMP specific assays varied in their correlation with WIF, with rank correlation coefficients ranging from 0.70 (Medac p-EIA) to 0.80 (Vircell EIA). The Genzyme Virotech assay showed poor specificity (5.6%; 95% confidence interval (CI), 0.68% to 18.7%)--it was reactive with 34 of the panel of 36 C psittaci/C pneumoniae positive sera. The MOMP based EIAs showed high specificity, particularly the Medac p-ELISA (97.2%; 95% CI, 85.5% to 99.9%)--only one serum was reactive. In view of the good correlation between WIF and the Genzyme Virotech EIA, a time resolved fluorescence immunoassay (TRFIA) was developed using the Genzyme Virotech antigen. Using an appropriate cut off the TRFIA assay showed excellent correlation with WIF.

CONCLUSIONS

The TRFIA assay may be useful as a screening assay, possibly in conjunction with one of the highly specific EIAs studied (for example, Medac p-EIA) to confirm the antibody specificity of sera selected by the screening assay.

Molecular evolution of freshwater snail intermediate hosts within the Bulinus forskalii group

Freshwater snails of the Bulinus forskalii group are one of four Bulinus species complexes responsible for the transmission of schistosomes in Africa and adjacent regions. The species status of these conchologically variable and widely distributed planorbids remains unclear, and parasite compatibility varies considerably amongst the eleven taxa defined, making unambiguous identification and differentiation important prerequisites for determining their distributions and evolutionary relationships. Random Amplified Polymorphic DNA (RAPD) analyses were used to investigate relationships between taxa, with particular emphasis on Central and West African representatives. RAPD-derived phylogenies were compared with those from other independent molecular markers, including partial sequences of mitochondrial cytochrome oxidase subunit I (COI) gene, and the nuclear ribosomal RNA internal transcribed spacer 1 region (ITS1). The phylogenetic reconstructions from the three approaches were essentially congruent, in that all methods of analysis gave unstable tree topologies or largely unresolved branches. There were large sequence divergence estimates between species, with few characters useful for determining relationships between species and limited within species differentiation. Nuclear and mtDNA sequence data from Central and East African representatives of the pan-African B. forskalii showed little evidence of geographical structuring. Despite the unresolved structure within the phylogenies, specimens from the same species clustered together indicating that all methods were capable of differentiating taxa but could not establish the inter-specific relationships with confidence. The limited genetic variation displayed by B. forskalii, and the evolution and speciose nature of the group, are discussed in the context of the increasingly arid climate of the late Miocene and early Pliocene of Africa.

Molecular approaches in the study of Biomphalaria glabrata--Schistosoma mansoni interactions: linkage analysis and gene expression profiling

Gene mapping and the generation of linkage groups are fundamental to an understanding of the organization and relationships of genes and marker sequences, providing a framework with which to investigate their association with traits of interest. The abundance of techniques available for generating polymorphic molecular markers, and recent advances in high throughput screening, have allowed the extension of map analysis to the tropical freshwater snail Biomphalaria glabrata, an important intermediate host for Schistosoma mansoni. Direct comparison of gene expression by differential display screening, without prior identification of candidate genes, can be combined with mapping to quantify the involvement of specific sequences in the schistosome resistance response, and other important host-parasite interactions. Here we discuss the application of current and emergent technologies to gene characterization and linkage analysis in snail-schistosome interactions. Preliminary results from the analysis of comparative gene expression in resistant and susceptible snails are also presented.

Time resolved fluorometric immunoassay, using europium labelled antihuman IgG, for the detection of human tetanus antitoxin in serum

A time resolved fluorometric immunoassay (TRFIA) has been developed and compared with an in house enzyme linked immunosorbent assay (ELISA) and commercial ELISA (Bindazyme) for the detection of tetanus antitoxin in human sera. A panel of 132 sera submitted for routine testing was used. Scatterplots showed a high degree of correlation between all three assays, although some divergence of results was apparent for low titre sera when comparing in house ELISA results with Bindazyme ELISA and TRFIA results. The TRFIA appeared to be more sensitive than the in house ELISA, and the Bindazyme assay compared well with the TRFIA. The intra-assay precision of all three assays, in terms of percentage coefficient of variation (%CV), was between 2.0% and 4.0%. The interassay precision ranged from 5% to 8% for the in house ELISA, 13% to 19% for the Bindazyme assay, and 11% to 13% for TRFIA. Both Bindazyme and TRFIA assays were simple to perform, accurate, reproducible, and amenable to automation. A particular benefit of the TRFIA was its large dynamic range, enabling tetanus antitoxin values of 0.01 IU/ml to 50 IU/ml to be measured with just one dilution of serum. TRFIA appears to be a useful serological technique worthy of further development.

Heteroblasty and preformation in mayapple, Podophyllum Peltatum (Berberidaceae): developmental flexibility and morphological constraint

Developmental preformation can constrain growth responses of shoots to current conditions, but there is potential for flexibility in development preceding formation of the preformed organs. Mayapple (Podophyllum peltatum) is strongly heteroblastic, producing rhizome scales, bud scales, and either a single vegetative foliage leaf or two foliage leaves on a sexual shoot. To understand how and when preformation constrains growth responses, we compare (1) how leaf homologs of the renewal shoot differ in development, (2) whether there are differences in shoot development that occur in advance of morphological determination of shoot type, and (3) whether there are points of developmental flexibility in renewal shoot growth prior to preformation of the foliage and floral organs. We use scanning electron microscopy and histology to show that the three vegetative leaves (both types of scale leaves and the vegetative foliage leaf) are similar in the initial establishment of an encircling and overarching leaf base. Differences among them are found in the timing of differentiation of the leaf base and in the relative timing and degree of growth of the lamina and petiole. In contrast, foliage leaves on sexual shoots show less expression of the leaf base and precocious growth of the lamina and petiole. Prior to shoot type determination, there are no morphological differences in the sequence or position of leaf homologs that predict final shoot type. In this colony, leaves at positions 12 and 13, on average, appear to be identical in development until they are between 700 and 800 μm in length, when it becomes possible to distinguish leaves that will become vegetative foliage leaves from additional bud scale leaves on vegetative or sexual shoots. We suggest that late developmental determination of leaves at positions 12 and 13 reflects ontogenetic sensitivity to a transition to flowering. Thus, in mayapple, heteroblasty appears to facilitate developmental flexibility prior to the point where shoot growth becomes constrained by preformation of determined aerial structures.

Spatio-temporal genetic variability in the schistosome intermediate host Biomphalaria pfeifferi

Genetic variation among temporally and spatially defined populations of the schistosome intermediate host, Biomphalaria pfeifferi, was analysed using RAPD markers. Snails were collected from each of eight sites that were 1-20 km apart, on four occasions, over a 2-year period. High levels of genetic variability were found within populations, between populations and between collections. Spatial differentiation and intrapopulation similarity were highest during periods of drought and were lowest following heavy rainfall. Temporal variability, consistent with founder effects, genetic drift and/or differential parasite pressure, was of similar or greater magnitude to that of the spatial variability. The results not only demonstrate that spatio-temporal sampling is necessary to understand the population genetics of short-lived species in variable habitats, but also provide empirical data to support current theoretical models of host-parasite co-evolution.

Towards benchmarking in British acute hospitals

The 1997 White Paper--The New NHS--on the future of the National Health Service accorded a high profile to the use of benchmarking as a means of improving efficiency over the following decade. Here, I examine the prospects for the successful adoption of benchmarking in the acute-hospital sector. A benchmarking model is superimposed upon a model of receptive contexts for change, and the components are used to explore the background to the development of benchmarking and likely attitudes towards its implementation. Where appropriate, empirical evidence is introduced to shed light on the ideas explored. I conclude that the wider political agenda accompanying benchmarking has potentially far-reaching implications for the re-distribution of resources on regional, or even national, bases. However, the steady drip-drip on stone is necessary to achieve results at local operational levels. Only by harnessing the strengths of extant cultures will efforts to identify and adopt the most efficient/effective medical practices succeed and potentially conflicting social tensions be resolved.

Molecular evidence supports an african affinity of the neotropical freshwater gastropod, Biomphalaria glabrata, say 1818, an intermediate host for Schistosoma mansoni

Freshwater snails of the genus Biomphalaria, Preston 1910, are the most important and widely distributed intermediate hosts of Schistosoma mansoni, the blood fluke responsible for human intestinal schistosomiasis, in Africa and the Neotropics. S. mansoni is thought to have been imported repeatedly into the Americas during the last 500 years with the African slave trade. Surprisingly considering that the New and Old World separated 95-106 million years (Myr) ago, the disease rapidly became established due to the presence of endemic susceptible hosts. Reconstructing the phylogenetic relationships within Biomphalaria may provide insights into the successful intercontinental spread of S. mansoni. Parsimony and distance analyses of mitochondrial and nuclear sequences show African taxa to be monophyletic and Neotropical species paraphyletic, with Biomphalaria glabrata forming a separate clade from other Neotropical Biomphalaria, and ancestral to the African taxa. A west to east trans-Atlantic dispersal of a B. glabrata-like taxon, possibly as recently as the Plio-Pleistocene (1.8-3.6 Myr ago) according to a general mitochondrial clock, would fit these observations. Vicariance or an African origin for B. glabrata followed by multiple introductions to South America over the past 500 years with the African slave trade seem unlikely explanations. Knowledge of the phylogenetic relationships among important intermediate host species may prove useful in furthering control measures which exploit genetic differences in susceptibility to parasites, and in elucidating the evolution of schistosome resistance.

Profiling of changes in gene expression during raspberry (Rubus idaeus) fruit ripening by application of RNA fingerprinting techniques

Processes that contribute to the overall phenomenon of fruit ripening are not well understood for many soft fruit species, including raspberry (Rubus idaeus L.) Recent biochemical data implicate ethylene and a range of cell wall hydrolases in ripening processes. However, the genes encoding these activities, and others related to ripening, remain to be characterised. With the advent of high-throughput RNA-fingerprinting techniques it is possible to characterise rapidly the changes in gene expression during developmental processes. This paper describes the application of two RNA-fingerprinting techniques (cDNA amplified fragment length polymorphism and differential display reverse transcription-polymerase chain reaction) to the ripening fruit of Rubus idaeus. Copy-DNA tags were isolated representing 34 genes, up-regulated during fruit ripening. The expression profiles of these genes were determined by RNA-blot analysis and their sequences were compared with those in public databases. Potential roles for some of these gene products are considered, providing valuable insights into the processes that underpin fruit ripening. Many of the cDNAs isolated in this study provide tools for the biotechnological improvement of fruit quality.

Immunity to diphtheria and tetanus in England and Wales

The immunity profile of the English and Welsh population to diphtheria and tetanus has been determined by measuring diphtheria and tetanus antitoxin levels for 3088 and 3142 sera, respectively. Time-resolved fluorimetric immunoassay - DELFIA was used to measure diphtheria antitoxin levels and an in-house, indirect ELISA to measure tetanus antitoxin levels. More than 80% of those aged between 2 and 20-24 years had protective diphtheria antitoxin levels of 0.01 IU/ml, or greater, and more than 80% of those aged between 4 and 35-39 years had protective tetanus antitoxin levels of 0.1 IU/ml, or greater. Only 29% and 53% of those aged 60 and over were protected against diphtheria and tetanus. Two increases of diphtheria antitoxin levels greater than 0.1 IU/ml and tetanus antitoxin levels greater than 1.0 IU/ml were apparent, starting at 4 and 14 years of age, which correspond with the policy of giving a diphtheria and tetanus toxoid booster on school entry and a tetanus plus low-dose diphtheria toxoid (recently introduced) booster to school leavers. This is the first comprehensive study of diphtheria and tetanus immunity in the English and Welsh population and shows that the accelerated schedule of immunisation, introduced in 1990, has effectively primed immunological memory against both these antigens and that boosting at school entry and at school leaving is effective in increasing levels of immunity.

Weight training injury trends: a 20-year survey

Weight training is a popular activity, but injuries can be a consequence. Research has documented the types and venues of weight training injuries.

OBJECTIVE

The objective of this study was to identify weight lifting injury trends.

DESIGN

A retrospective review of data from US emergency departments (EDs) that reported injuries from weight training and weight training equipment. The data include people who were treated for injuries from weight training or weight equipment from October 1, 1978, through December 31, 1998, and were identified by the National Electronic Injury Surveillance System (NEISS).

RESULTS

NEISS identified 20,489 weight training-related injuries. An estimated 980,173 persons were treated in EDs for injuries related to weight training activity or equipment during the study period. The number of ED-treated injuries has increased 35% since 1978. About one of four injuries occurred from the misuse or abuse of weight training equipment.

CONCLUSION

Cautionary messages should be aimed at young children, older adults, and users of home gyms. Those who train with weights should be instructed in the proper use of weight equipment.

Epidemiology of personal watercraft-related injury on Arkansas waterways, 1994-1997: identifying priorities for prevention

Personal watercraft (PWC) use has increased rapidly in the past ten years. Consequences of the increased use are collisions and injuries. This study was conducted to determine the etiology and the characteristics surrounding PWC collisions and injury associated with the use of these popular water recreational vehicles and determine countermeasures. Methods included obtaining boating accident reports limited to PWCs from the Arkansas Game and Fish Commission for the years 1994 through 1997. Results show that there were 126 incidents involving 141 vessels and over $156,000 (US) in property damage. Almost two-fifths of PWC users were injured, mainly head trauma and fractures to the lower limbs. There were five reported fatalities. Study suggests that PWC collisions and injury are increasing. With increased use and popularity, this trend will continue unless sustained efforts in prevention are established. Changes in policy, education and manufacturing standards need to be considered and initiated to provide for safe PWC operation and boating environment.

Use of differential display to detect changes in gene expression in the intermediate snail host Biomphalaria glabrata upon infection with Schistosoma mansoni

Changes in gene expression in Biomphalaria glabrata following infection with Schistosoma mansoni have been investigated using a modified differential display approach. RNA was extracted from ovotestis, mantle tissue and anterior nephridium of control and exposed snails at 2 time-points (4 h and 24 h) post-exposure and analysed by RNA fingerprinting. A number of transcripts were identified; some novel and some homologous to mRNAs in GenEMBL that were previously unknown in B. glabrata. Down regulation of one 241 bp mRNA expressed sequence fragment - with an open reading frame showing 48% identity to a cytochrome p450 over 80 residues - has been confirmed using semi-quantitative RT-PCR. Preliminary classification of B. glabrata cyp450 sequence shows it to fall into CLAN 2 of the cytochrome p450 superfamily. Differential display has been successful in identifying changes in gene expression in Biomphalaria glabrata upon infection with Schistosoma mansoni and promises to be a useful technique for the investigation of the interaction between host and parasite.

Late onset of accessory pathway conduction in a patient with complete AV block

This case report discusses a patient with complete AV block in early childhood. The patient required a permanent pacemaker. At 6 years of age, intermittent preexcited beats were noted on telephonic transmissions. At 7 years of age, 1:1 preexcitation was noted in sinus rhythm. Therefore, late onset of antegrade accessory pathway function is demonstrated. This case provides evidence of developmental changes in accessory pathways. This may explain age related differences in the onset of narrow complex tachycardia in the school age years.

An Essay on Juvenility, Phase Change, and Heteroblasty in Seed Plants

Phase change (the change from nonreproductive to reproductive status) and heteroblasty (ontogenetic changes in vegetative metamers) are two determinants of longitudinal asymmetry in plants. These concepts are critically important to understanding the regulation of plant development as well as morphological evolution and life-history variation. Since Goebel, the two have been conflated. This article questions how phase change and heteroblasty are delimited and explores some of the problems that arise in the explicit or implicit link between them, given that several lines of evidence indicate that they are distinct and independent facets of plant development. It is suggested that problems are perpetuated through use of the terms "juvenile" and "adult" to describe both phenomena.

Drowning among personal watercraft passengers: the ability of personal flotation devices to preserve life on Arkansas waterways, 1994-1997

Personal flotation devices (PFD) are promoted and in many states are required for safe boating practices and to prevent drowning. Primary use of PFDs is associated with water sports (water skiing, tubing, etc.), boating and other water activities. Their purpose is to preserve life and prevent drowning. However, their effectiveness to prevent drowning and near-drowning has not been well established. The purpose of this investigation was to determine the effectiveness of PFDs to prevent drowning and near-drowning of individuals involved in personal watercraft (PWC) crashes. Methods include the 48-month collection of PWC crash data from the Arkansas Game and Fish Commission for 1994-1997. Information on PFD use, swimming experience, whether passengers were ejected from the watercraft and crash cause was queried. Results show that 38% were not swimmers, 98% wore a PFD and 54% were ejected from the PWC. Alcohol was a causal factor in six crashes and one death. It is estimated that PFDs saved 38 Arkansans who could have drowned. This study highlights one example of the effectiveness of PFDs to prevent mortality and morbidity.