Computable phenotype for real-world, data-driven retrospective identification of relapse in ANCA-associated vasculitis

OBJECTIVE

ANCA-associated vasculitis (AAV) is a relapsing-remitting disease, resulting in incremental tissue injury. The gold-standard relapse definition (Birmingham Vasculitis Activity Score, BVAS>0) is often missing or inaccurate in registry settings, leading to errors in ascertainment of this key outcome. We sought to create a computable phenotype (CP) to automate retrospective identification of relapse using real-world data in the research setting.

METHODS

We studied 536 patients with AAV and >6 months follow-up recruited to the Rare Kidney Disease registry (a national longitudinal, multicentre cohort study). We followed five steps: (1) independent encounter adjudication using primary medical records to assign the ground truth, (2) selection of data elements (DEs), (3) CP development using multilevel regression modelling, (4) internal validation and (5) development of additional models to handle missingness. Cut-points were determined by maximising the F1-score. We developed a web application for CP implementation, which outputs an individualised probability of relapse.

RESULTS

Development and validation datasets comprised 1209 and 377 encounters, respectively. After classifying encounters with diagnostic histopathology as relapse, we identified five key DEs; DE1: change in ANCA level, DE2: suggestive blood/urine tests, DE3: suggestive imaging, DE4: immunosuppression status, DE5: immunosuppression change. F1-score, sensitivity and specificity were 0.85 (95% CI 0.77 to 0.92), 0.89 (95% CI 0.80 to 0.99) and 0.96 (95% CI 0.93 to 0.99), respectively. Where DE5 was missing, DE2 plus either DE1/DE3 were required to match the accuracy of BVAS.

CONCLUSIONS

This CP accurately quantifies the individualised probability of relapse in AAV retrospectively, using objective, readily accessible registry data. This framework could be leveraged for other outcomes and relapsing diseases.

Delivery room glucose to reduce the risk of admission hypoglycemia in preterm infants: a systematic literature review

AIMS

In order to mitigate early hypoglycemia in preterm infants, some clinicians have recently explored interventions such as delivery room commencement of dextrose infusions or delivery room administration of buccal dextrose gel. This review aimed to systematically investigate the literature regarding the provision of delivery room (prior to admission) parenteral glucose as a method to reduce the risk of initial hypoglycemia (measured at the time of NICU admission blood testing) in preterm infants.

MATERIALS AND METHODS

Using PRISMA guidelines a literature search (May 2022) was conducted using PubMed, Embase, Scopus, Cochrane Library, OpenGrey, and Prospero databases. The clinicaltrials.gov database was searched for possible completed/ongoing clinical trials. Studies that included moderate preterm (≤33⁺⁶ weeks) or younger birth gestations or very low birth weight (or smaller) infants, and that administered parenteral glucose in the delivery room were included. The literature was appraised via data extraction, narrative synthesis, and critical review of the study data.

RESULTS

A total of five studies (published 2014-2022) were eligible for inclusion (three before-after "quasi-experimental" studies, one retrospective cohort study, and one case-control study). Most included studies used intravenous dextrose as the intervention. Individual study effects (odds ratios) favored the intervention in all included studies. It was felt that the low number of studies, the variability in study design, and the nonadjustment for confounding co-interventions (co-exposures) precluded a meta-analysis. Quality assessment of the studies revealed a spectrum of bias from low to high risk, however, most studies had moderate to high risk of bias, and their direction of bias favored the intervention.

CONCLUSIONS

This extensive search and systematic appraisal of the literature indicates that there exists few studies (these are low grade and at moderate to high risk of bias) for the interventions of either intravenous or buccal dextrose given in the delivery room. It is not clear if these interventions impact on rates of early (NICU admission) hypoglycemia in these preterm infants. Obtaining intravenous access in the delivery room is not guaranteed and can be difficult in these small infants. Future research should consider various routes for commencing delivery room glucose in these preterm infants and should take the form of randomized controlled trials.

Anxiety as a Risk Factor for Postoperative Delirium in Elective Spine Deformity Surgeries: A National Database Study

Introduction Generalized anxiety disorder has become one of the most prevalent mental health disorders in the United States. In addition, postoperative delirium has been shown to increase hospital stay, increase mortality, and increased healthcare costs. Few studies have looked at the prevalence of postoperative delirium in patients diagnosed with anxiety undergoing elective spinal deformity procedures. The purpose of this study was to determine if anxiety is a risk factor for postoperative delirium in elective spinal deformity surgeries. Methods The authors performed a retrospective analysis using the TriNetX Research Database. Patients diagnosed with kyphosis or lordosis who then underwent elective spinal correction surgeries were identified. This group was then separated based on the diagnosis of a generalized anxiety disorder before the operation versus no diagnosis. Propensity score adjustment, based on mental disorders and other risk factors, was then used to match cohorts on baseline demographics and characteristics. Analysis was performed on the primary outcome of postoperative delirium, with secondary outcomes of upper respiratory tract infections, surgical site infections, sepsis, ventilator dependence, convulsions, stroke, emergency department visits, myocardial infarction, pulmonary embolism, and urinary retention within 30 days after surgery. Results Our search included 1,211 patients with a diagnosis of anxiety and 8,055 patients without anxiety. After propensity score matching, 996 patients remained in each cohort. Statistical analysis showed significant outcomes between the matched cohorts in the anxiety group for postoperative delirium (OR 2.788; 1.587-4.899) and convulsions (OR 1.615; 1.006-2.592). All other outcomes were not significant after propensity score matching. Conclusion These results showed generalized anxiety disorder is a risk factor for postoperative delirium and convulsions after elective spine surgery. Further research is necessary on the effects of mental health disorders on postoperative delirium and other outcomes to better understand the risks in this population.

Arachnoiditis Ossificans in the Thoracic Spine With Associated Cyst and Syringomyelia: A Rare, Intraoperative Finding Complicating Dural Opening

Arachnoiditis ossificans (AO) is a rare spinal pathology that develops because of bony metaplasia secondary to chronic inflammation. AO may present with debilitating myelopathy secondary to nerve root compression, making it distinct from spinal calcification commonly seen with aging. AO is extremely rare, having been reported less than 100 times, most commonly in the thoracic spine. Even rarer still, AO has been associated with syringomyelia and arachnoid cyst because of associated cerebrospinal fluid (CSF) flow disruption. In this report, we describe a case of AO that presented with right shoulder pain, right-hand numbness, and bilateral lower extremity fatigue who had syringomyelia and arachnoid cyst discovered on MRI imaging. When brought to the operating room for syrinx shunting and cyst fenestration the dural opening was complicated by severe calcification and a diagnosis of AO was made. The patient was treated with partial resection of the calcified plaques. Syringomyelia shunting was abandoned due to low volume. Post-operatively, the patient had improvement in their myelopathy though syrinx was still visualized on follow-up imaging. This report reviews the pathology, clinical and radiographic diagnosis, and treatment strategies for arachnoiditis ossificans.

Cervical Pediatric Spine Trauma Managed With Open Spinal Fixation and Instrumentation and a Review of the Literature

Cervical spine injuries in the pediatric population are rare. Most injuries to the cervical spinal cord and vertebral column can be managed nonoperatively; however, surgical management may be required in certain clinical scenarios. A posterior surgical approach has been previously preferred; however, the utilization of anterior spinal fixation and instrumentation has been limited. We present a small case series of patients presenting with a traumatic cervical spine injury and detail the feasibility of craniocervical junction (CVJ) and subaxial spinal fixation in the pediatric population.

We report four cases involving pediatric patients, all of whom presented with cervical spine injuries necessitating operative intervention using a combination of the anterior and posterior operative approaches. All four patients recovered well, did not require surgical revision, and were neurologically intact at the last follow-up. 

Therefore, we conclude that spinal arthrodesis is a safe, effective way to manage spinal injuries in the cervical spine following traumatic injury.

Size Matters: The Impact of Training Size in Taxonomically-Enriched Word Embeddings

Word embeddings trained on natural corpora (e.g., newspaper collections, Wikipedia or the Web) excel in capturing thematic similarity (“topical relatedness”) on word pairs such as ‘coffee’ and ‘cup’ or ’bus’ and ‘road’. However, they are less successful on pairs showing taxonomic similarity, like ‘cup’ and ‘mug’ (near synonyms) or ‘bus’ and ‘train’ (types of public transport). Moreover, purely taxonomy-based embeddings (e.g. those trained on a random-walk of WordNet’s structure) outperform natural-corpus embeddings in taxonomic similarity but underperform them in thematic similarity. Previous work suggests that performance gains in both types of similarity can be achieved by enriching natural-corpus embeddings with taxonomic information from taxonomies like Word-Net. This taxonomic enrichment can be done by combining natural-corpus embeddings with taxonomic embeddings (e.g. those trained on a random-walk of WordNet’s structure). This paper conducts a deep analysis of this assumption and shows that both the size of the natural corpus and of the random-walk coverage of the WordNet structure play a crucial role in the performance of combined (enriched) vectors in both similarity tasks. Specifically, we show that embeddings trained on medium-sized natural corpora benefit the most from taxonomic enrichment whilst embeddings trained on large natural corpora only benefit from this enrichment when evaluated on taxonomic similarity tasks. The implication of this is that care has to be taken in controlling the size of the natural corpus and the size of the random-walk used to train vectors. In addition, we find that, whilst the WordNet structure is finite and it is possible to fully traverse it in a single pass, the repetition of well-connected WordNet concepts in extended random-walks effectively reinforces taxonomic relations in the learned embeddings.

Egyptian metallic inks on textiles from the 15th century BCE unravelled by non-invasive techniques and chemometric analysis

The development of black inks has enabled writing to become an established method of communication in history. Although a large research effort has been devoted to the study of pigments and dyes used in ancient Egypt to decorate burial walls and furnishings, or to write on papyrus, to date little attention has been paid to the nature and technology of inks used on ritual and daily-use textiles, which may have fostered the transfer of metallic ink technology onto papyrus and parchment supports. We report about inks from 15^th century BCE Egyptian textiles by combining non-invasive techniques, including ultraviolet (UV) reflected imaging, near-infrared reflectography (NIRR), X-ray fluorescence (XRF) spectroscopy, Raman spectroscopy and prompt-gamma-activation-analysis (PGAA). It is argued that the inks are related to the family of iron gall inks, whose introduction is commonly attributed to the third century BCE. This interpretation frames the technology of writing on fabrics, used by the ancient Egyptians, in a different time, thus providing new information on the genesis of mordant inks in the ancient Mediterranean cultures. We anticipate our study to be a starting point for further and more sophisticated investigations of textiles, which will clarify the origin of metallic ink in the ancient world.

Correction: An open-data-driven agent-based model to simulate infectious disease outbreaks

[This corrects the article DOI: 10.1371/journal.pone.0208775.].

An open-data-driven agent-based model to simulate infectious disease outbreaks

Agent-based models are a tool that can be used to better understand the dynamics of an infectious disease outbreak. An infectious disease outbreak is influenced by many factors including vaccination or immunity levels, population density, and the age structure of the population. We hypothesize that these factors along with interactions of factors and the actions of individuals would lead to outbreaks of different size and severity even in two towns that appear similar on paper. Thus, it is necessary to implement a model that is able to capture these interactions and the actions of individuals. Using openly available data we create a data-driven agent-based model to simulate the spread of an airborne infectious disease in an Irish town. Agent-based models have been known to produce results that include the emergence of patterns and behaviours that are not directly programmed into the model. Our model is tested by simulating an outbreak of measles that occurred in Schull, Ireland in 2012. We simulate the same outbreak in 33 different towns and look at the correlations between the model results and the town characteristics (population, area, vaccination rates, age structure) to determine if the results of the model are affected by interactions of those town characteristics and the decisions on the agents in the model. As expected our results show that the outbreaks are not strongly correlated with any of the main characteristics of the towns and thus the model is most likely capturing such interactions and the agent-based model is successful in capturing the differences in the outbreaks.

A scoring system predicting the clinical course of CLPB defect based on the foetal and neonatal presentation of 31 patients

Recently, CLPB deficiency has been shown to cause a genetic syndrome with cataracts, neutropenia, and 3-methylglutaconic aciduria. Surprisingly, the neurological presentation ranges from completely unaffected to patients with virtual absence of development. Muscular hypo- and hypertonia, movement disorder and progressive brain atrophy are frequently reported. We present the foetal, peri- and neonatal features of 31 patients, of which five are previously unreported, using a newly developed clinical severity scoring system rating the clinical, metabolic, imaging and other findings weighted by the age of onset. Our data are illustrated by foetal and neonatal videos. The patients were classified as having a mild (n = 4), moderate (n = 13) or severe (n = 14) disease phenotype. The most striking feature of the severe subtype was the neonatal absence of voluntary movements in combination with ventilator dependency and hyperexcitability. The foetal and neonatal presentation mirrored the course of disease with respect to survival (current median age 17.5 years in the mild group, median age of death 35 days in the severe group), severity and age of onset of all findings evaluated. CLPB deficiency should be considered in neonates with absence of voluntary movements, respiratory insufficiency and swallowing problems, especially if associated with 3-methylglutaconic aciduria, neutropenia and cataracts. Being an important differential diagnosis of hyperekplexia (exaggerated startle responses), we advise performing urinary organic acid analysis, blood cell counts and ophthalmological examination in these patients. The neonatal presentation of CLPB deficiency predicts the course of disease in later life, which is extremely important for counselling.

Snack bar compositions and their acute glycaemic and satiety effects

BACKGROUND AND OBJECTIVES

Maintaining blood glucose within homeostatic limits and eating foods that sup-press hunger and promote satiety have beneficial impacts for health. This study investigated the glycaemic re-sponse and satiety effects of a serving size of a healthier snack bar, branded Nothing Else, that met the required nutrient profiling score criteria for a health claim, in comparison to two top-selling commercial snack bars.

METHODS AND STUDY DESIGN

In an experimental study, 24 participants aged >=50 years were recruited. On three different days blood glucose concentration was measured twice at baseline and 15, 30, 45, 60, 90 and 120 minutes after consumption of a serving size of each bar. Satiety effects were self-reported hunger, fullness, desire to eat, and amount could eat ratings on visual analogue scales.

RESULTS

The incremental area under the blood glucose response curve (iAUC) over two hours for the Nothing Else bar was 30% lower than commercial Bar 2 (p<0.001). At 45 minutes after eating, the Nothing Else bar induced the highest fullness rating and lowest hunger rating among the three snack bars. At two hours, fullness induced by the Nothing Else bar was twice that of Bar 2 (p=0.019), but not different to Bar 1 (p=0.212).

CONCLUSIONS

The Nothing Else snack bar developed using the nutrient profiling scheme as a guideline, with its high protein and dietary fibre contents, had a lower glycaemic impact and induced a higher subjective satiety than the two commercial snack bars of equal weight.

The first occurrence of a CTX-M ESBL-producing Escherichia coli outbreak mediated by mother to neonate transmission in an Irish neonatal intensive care unit

BACKGROUND

Escherichia coli (E. coli) comprise part of the normal vaginal microflora. Transfer from mother to neonate can occur during delivery resulting, sometimes, in neonatal bacterial disease. Here, we aim to report the first outbreak of CTX-M ESBL-producing E. coli with evidence of mother-to-neonate transmission in an Irish neonatal intensive care unit (NICU) followed by patient-to-patient transmission.

METHODS

Investigation including molecular typing was conducted. Infection was defined by clinical and laboratory criteria and requirement for antimicrobial therapy with or without positive blood cultures. Colonisation was determined by isolation without relevant symptoms or indicators of infection.

RESULTS

Index case was an 8-day-old baby born at 34 weeks gestation who developed ESBL-producing E. coli infections at multiple body sites. Screening confirmed their mother as colonised with ESBL-producing E. coli. Five other neonates, in the NICU simultaneously with the index case, also tested positive. Of these, four were colonised while one neonate developed sepsis, requiring antimicrobial therapy. The second infected neonate's mother was also colonised by ESBL-producing E. coli. Isolates from all eight positive patients (6 neonates, 2 mothers) were compared using pulsed-field gel electrophoresis (PFGE). Two distinct ESBL-producing strains were implicated, with evidence of transmission between mothers and neonates for both strains. All isolates were confirmed as CTX-M ESBL-producers. There were no deaths associated with the outbreak.

CONCLUSIONS

Resources were directed towards control interventions focused on hand hygiene and antimicrobial stewardship, which ultimately proved successful. Since this incident, all neonates admitted to the NICU have been screened for ESBL-producers and expectant mothers are screened at their first antenatal appointment. To date, there have been no further outbreaks.

Identification of the novel B*27:144 allele in an Irish Individual

The sequence of HLA-B*27:144 differs from HLA-B*27:05:02 by one nucleotide change at position 506.

Prophylactic indomethacin and intestinal perforation in extremely low birth weight infants

OBJECTIVE

Prophylactic indomethacin reduces severe intraventricular hemorrhage but may increase spontaneous intestinal perforation (SIP) in extremely low birth weight (ELBW) infants. Early feedings improve nutritional outcomes but may increase the risk of SIP. Despite their benefits, use of these therapies varies largely by physician preferences in part because of the concern for SIP.

METHODS

This was a cohort study of 15,751 ELBW infants in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network from 1999 to 2010 who survived beyond 12 hours after birth. The risk of SIP was compared between groups of infants with and without exposure to prophylactic indomethacin and early feeding in unadjusted analyses and in analyses adjusted for center and for risks of SIP.

RESULTS

Among infants exposed to prophylactic indomethacin, the risk of SIP did not differ between the indomethacin/early-feeding group compared with the indomethacin/no-early-feeding group (adjusted relative risk [RR] 0.74, 95% confidence interval [CI] 0.49-1.11). The risk of SIP was lower in the indomethacin/early-feeding group compared with the no indomethacin/no-early-feeding group (adjusted RR 0.58, 95% CI 0.37-0.90, P = .0159). Among infants not exposed to indomethacin, early feeding was associated with a lower risk of SIP compared with the no early feeding group (adjusted RR 0.53, 95% CI 0.36-0.777, P = .0011).

CONCLUSIONS

The combined or individual use of prophylactic indomethacin and early feeding was not associated with an increased risk of SIP in ELBW infants.

A review of carbon dioxide monitoring in preterm newborns in the delivery room

INTRODUCTION

The physiologic adaptation to extra uterine life during the immediate neonatal period is unique. Many newborns require assistance in this adaptive process. Recent evidence now supports titrating oxygen to guide resuscitation but no guidance is provided on utilizing exhaled CO2 measurements.

AIM

To review the current evidence relating to the use of CO2 monitoring in preterm newborns in the delivery room.

METHODS

Search was performed using the Cochrane Central Register of Controlled Trials, MEDLINE (1966-2014) and PREMEDLINE, EMBASE (1980-2014), CINAHL (1982-2014), Web of Science (1975-2014) and the Oxford Database of Perinatal Trials.

RESULTS

The search revealed 21 articles relating to CO2 detection, either quantitative or qualitative, in the newborn infant. The majority of these were observational studies, eight relating to CO2 detection as a means of confirming correct endotracheal tube placement in the newborn infant. The other indication is for mask ventilation, and there is one randomized control trial and four observational studies of CO2 detection during mask ventilation. The overall recommendation for CO2 detection for both clinical uses in the delivery suite is level B.

DISCUSSION

CO2 detection may be of particular benefit for preterm infants in the delivery suite. However there is a need for further research into CO2 detection, in particular capnography, as a means of confirming effective PPV in neonatal resuscitation.

Coalescent simulation in continuous space: algorithms for large neighbourhood size

Many species have an essentially continuous distribution in space, in which there are no natural divisions between randomly mating subpopulations. Yet, the standard approach to modelling these populations is to impose an arbitrary grid of demes, adjusting deme sizes and migration rates in an attempt to capture the important features of the population. Such indirect methods are required because of the failure of the classical models of isolation by distance, which have been shown to have major technical flaws. A recently introduced model of extinction and recolonisation in two dimensions solves these technical problems, and provides a rigorous technical foundation for the study of populations evolving in a spatial continuum. The coalescent process for this model is simply stated, but direct simulation is very inefficient for large neighbourhood sizes. We present efficient and exact algorithms to simulate this coalescent process for arbitrary sample sizes and numbers of loci, and analyse these algorithms in detail.

Oronasopharyngeal suction versus wiping of the mouth and nose at birth: a randomised equivalency trial

BACKGROUND

Wiping of the mouth and nose at birth is an alternative method to oronasopharyngeal suction in delivery-room management of neonates, but whether these methods have equivalent effectiveness is unclear.

METHODS

For this randomised equivalency trial, neonates delivered at 35 weeks' gestation or later at the University of Alabama at Birmingham Hospital, Birmingham, AL, USA, between October, 2010, and November, 2011, were eligible. Before birth, neonates were randomly assigned gentle wiping of the face, mouth (implemented by the paediatric or obstetric resident), and nose with a towel (wipe group) or suction with a bulb syringe of the mouth and nostrils (suction group). The primary outcome was the respiratory rate in the first 24 h after birth. We hypothesised that respiratory rates would differ by fewer than 4 breaths per min between groups. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01197807.

FINDINGS

506 neonates born at a median of 39 weeks' gestation (IQR 38-40) were randomised. Three parents withdrew consent and 15 non-vigorous neonates with meconium-stained amniotic fluid were excluded. Among the 488 treated neonates, the mean respiratory rates in the first 24 h were 51 (SD 8) breaths per min in the wipe group and 50 (6) breaths per min in the suction group (difference of means 1 breath per min, 95% CI -2 to 0, p<0·001).

INTERPRETATION

Wiping the nose and mouth has equivalent efficacy to routine use of oronasopharyngeal suction in neonates born at or beyond 35 weeks' gestation.

FUNDING

None.

Inference in two dimensions: allele frequencies versus lengths of shared sequence blocks

We outline two approaches to inference of neighbourhood size, N, and dispersal rate, σ(2), based on either allele frequencies or on the lengths of sequence blocks that are shared between genomes. Over intermediate timescales (10-100 generations, say), populations that live in two dimensions approach a quasi-equilibrium that is independent of both their local structure and their deeper history. Over such scales, the standardised covariance of allele frequencies (i.e. pairwise FST) falls with the logarithm of distance, and depends only on neighbourhood size, N, and a 'local scale', κ; the rate of gene flow, σ(2), cannot be inferred. We show how spatial correlations can be accounted for, assuming a Gaussian distribution of allele frequencies, giving maximum likelihood estimates of N and κ. Alternatively, inferences can be based on the distribution of the lengths of sequence that are identical between blocks of genomes: long blocks (>0.1 cM, say) tell us about intermediate timescales, over which we assume a quasi-equilibrium. For large neighbourhood size, the distribution of long blocks is given directly by the classical Wright-Malécot formula; this relationship can be used to infer both N and σ(2). With small neighbourhood size, there is an appreciable chance that recombinant lineages will coalesce back before escaping into the distant past. For this case, we show that if genomes are sampled from some distance apart, then the distribution of lengths of blocks that are identical in state is geometric, with a mean that depends on N and σ(2).

Mortality and intestinal failure in surgical necrotizing enterocolitis

BACKGROUND/PURPOSE

To examine whether as initial surgical intervention for necrotizing enterocolitis, primary peritoneal drainage as compared to primary laparotomy is associated with increased mortality or intestinal failure.

METHODS

Retrospective observational study of 240 infants with surgical necrotizing enterocolitis.

RESULTS

There was no difference concerning the composite outcome of mortality before discharge or survival with intestinal failure after adjusting for known covariates (Odds Ratio 1.73, 95% CI 0.88, 3.40). More surviving infants in the peritoneal drainage with subsequent salvage or secondary laparotomy had intestinal failure compared to those who received a peritoneal drain without subsequent laparotomy and survived (12% vs. 14% vs. 1%, p=0.015).

CONCLUSIONS

There is no difference between peritoneal drainage and laparotomy in infants with surgical necrotizing enterocolitis concerning the combined outcome of mortality or survival with intestinal failure. There is increased intestinal failure in surviving infants treated with peritoneal drain with either subsequent salvage or secondary laparotomy compared to peritoneal drainage alone.

Genetic hitchhiking in spatially extended populations

When a mutation with selective advantage s spreads through a panmictic population, it may cause two lineages at a linked locus to coalesce; the probability of coalescence is exp(-2rT), where T∼log(2Ns)/s is the time to fixation, N is the number of haploid individuals, and r is the recombination rate. Population structure delays fixation, and so weakens the effect of a selective sweep. However, favourable alleles spread through a spatially continuous population behind a narrow wavefront; ancestral lineages are confined at the tip of this front, and so coalesce rapidly. In extremely dense populations, coalescence is dominated by rare fluctuations ahead of the front. However, we show that for moderate densities, a simple quasi-deterministic approximation applies: the rate of coalescence within the front is λ∼2g(η)/(ρℓ), where ρ is the population density and ℓ=σ2/s is the characteristic scale of the wavefront; g(η) depends only on the strength of random drift, η=ρσs/2. The net effect of a sweep on coalescence also depends crucially on whether two lineages are ever both within the wavefront at the same time: even in the extreme case when coalescence within the front is instantaneous, the net rate of coalescence may be lower than in a single panmictic population. Sweeps can also have a substantial impact on the rate of gene flow. A single lineage will jump to a new location when it is hit by a sweep, with mean square displacement σeff(2)/σ(2)=(8/3)(L/ℓ)(Λ/R); this can be substantial if the species' range, L, is large, even if the species-wide rate of sweeps per map length, Λ/R, is small. This effect is half as strong in two dimensions. In contrast, the rate of coalescence between lineages, at random locations in space and on the genetic map, is proportional to (c/L)(Λ/R), where c is the wavespeed: thus, on average, one-dimensional structure is likely to reduce coalescence due to sweeps, relative to panmixis. In two dimensions, genes must move along the front before they can coalesce; this process is rapid, being dominated by rare fluctuations. This leads to a dramatically higher rate of coalescence within the wavefront than if lineages simply diffused along the front. Nevertheless, the net rate of coalescence due to a sweep through a two-dimensional population is likely to be lower than it would be with panmixis.

The impact of the two-week wait rule on the diagnosis and management of bladder cancer in a single UK institution

INTRODUCTION

The objective of this study was to investigate the impact of the 2-week wait rule on patient waiting times for the diagnosis and treatment of bladder cancer.

PATIENTS AND METHODS

Data reporting the waiting times from diagnosis to treatment for 100 consecutive patients newly diagnosed with bladder cancer immediately before and after the implementation of the 2-week wait rule were compared. The data were collected both prospectively and retrospectively from cancer multidisciplinary team meeting files and patient records. Various steps of the patient pathway were analysed including waiting times from referral to consultation as well as time to investigation and first treatment. Data were also analysed based upon tumour stage/grade and whether referrals were made on an urgent or routine basis.

RESULTS

One hundred newly diagnosed patients with bladder cancer in each group covered a period of 4-5 years (1997-2001 and 2001-2006). Following the introduction of the 2-week wait rule, there was a 47.6% reduction in the time from referral to first consultation with a specialist (42 days vs 22 days; P < 0.001). The time between first investigation and treatment has not reduced significantly. We also found that, despite the introduction of the 2-week wait rule, only 42% of the patients were diagnosed with bladder cancer using this pathway. Patients referred as 'routine' waited longer to be seen in hospital although there was no significant delay in receiving treatment.

CONCLUSIONS

The introduction of the 2-week wait rule has significantly reduced the time patients with bladder cancer wait for their first consultation with a specialist. However, there is no significant change in the time between first consultation and treatment.

Premedication before intubation in UK neonatal units: a decade of change?

AIMS

To ascertain the prevalence of premedication before intubation and the choice of drugs used in UK neonatal units in 2007 and assess changes in practice since 1998.

METHODS

A structured telephone survey of 221 eligible units was performed. 214 of the units surveyed completed the telephone questionnaire. The units were subdivided into those that routinely intubated and ventilated neonates (routine group) and those that intubated neonates prior to transfer to a regional unit (transfer group). A similar study was performed by one of the authors in 1998. The same telephone methodology was used in both studies.

RESULTS

Premedication for newborn intubations was provided by 93% (198/214) of all UK units and 76% (162/214) had a written policy or guideline concerning premedication prior to elective intubation. Of those 198 units which premedicate, morphine was the most widely used sedative for newborn intubations with 80% (158/198) using either morphine alone or in combination with other drugs. The most widely used combination was morphine and suxamethonium+/-atropine, which was used by 21% (41/198) of all units. 78% (154/198) of all units administered a paralytic agent.

CONCLUSIONS

There has been substantial growth over the last decade in the number of UK neonatal units that provide some premedication for non-emergent newborn intubation, increasing from 37% in 1998 to 93% in 2007. This includes a concomitant increase in the use of paralytic drugs from 22% to 78%. However, the variety of drugs used merits further research.

The effect of zinc and vitamin C supplementation on the immune status of patients with Crohn's disease

The immune status of 29 patients with Crohn's disease given oral supplements of Vitamin C, zinc or placebo for three-week periods was studied. Collectively, the patients showed T-cell hyporesponsiveness, as assessed by phytohaemagglutinin stimulation, which was significantly improved by Vitamin C. Both monocyte function, as assessed by latex phagocytosis, and pan T-Cell number were significantly reduced and were not influenced by supplementation. Humoral immunity, assessed by pokeweed mitogen-induced immunoglobulin synthesis, was normal and remained unchanged. Vitamin C supplements improved T-cell function in Crohn's disease, whereas neither Vitamin C nor zinc had a measurable effect on humoral immunity.

A unique case of a malignant Sertoli cell tumour with cutaneous metastasis

Pure Sertoli cell tumours (SCTs) represent less than 1% of testicular neoplasms and malignant forms are rare. We present a unique case of a 69-year-old man who initially underwent inguinal orchidectomy for a malignant SCT. He then subsequently developed a paraumbilical cutaneous lesion which was histologically identical to the primary tumour. SCTs rarely metastasise. This is the first case of SCT with cutaneous metastasis described in the literature.

Human leucocyte antigen class II polymorphism in Irish patients with multiple sclerosis

The contribution of human leucocyte antigen (HLA) to the genetic risk for multiple sclerosis (MS) in patients of Northern European Caucasoid ancestry has been known since the 1970s. The northern part of Ireland, including county Donegal, is known to be a high-risk area for the development of MS. Recorded prevalence rates for county Wexford in the south-east Ireland have been markedly lower and suggest the existence of a prevalence gradient within the island. To evaluate the association of HLA-DRB1 and -DQB1 haplotypes with MS in both Wexford and Donegal, we examined a total of 118 patients and 400 regionally matched controls. The aim of this exploratory study was to test the possibility of heterogeneity in HLA class II associations with MS and to identify potential predisposing or protective haplotypes, associated with MS risk in Ireland. We confirmed the association of DRB1*1501-DQB1*0602 haplotype carriage with MS in both Wexford [odds ratio (OR) = 2.95, P= 0.0020, P(cor)= 0.0220] and Donegal (OR = 2.29, P= 0.0030, P(cor)= 0.0420). A higher frequency and a significantly higher homozygosity rate of this haplotype in Donegal are likely contributing factors to the higher prevalence of MS in Donegal compared with Wexford. The distribution of HLA class II alleles among Irish MS patients and controls establishes that there is heterogeneity in HLA class II associations with MS within Ireland.