Merkel cell carcinoma of the head and neck in the south-east of England

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine malignancy of the skin. Its incidence is increasing with half of cases involving the head and neck. To the best of our knowledge, few large studies have been published in the UK, and to date this is the largest reported series of head and neck MCC. We retrospectively reviewed the outcomes of patients with MCC in three hospitals in the south-east of England over a 12-year period (2008-2019). Diagnosis was based on histological data following biopsy. Overall survival and disease-specific survival were calculated using Kaplan-Meier and log-rank tests. Fifty-eight patients met the inclusion criteria (24 stage I, 22 stage II, 9 stage III, and 3 unclassified). Median disease-free survival was 36 months (95% CI 0 to 77.2) and median overall survival 50 months (95% CI 29.9 to 70). Overall five-year survival was 34.4% (95% CI 17% to 52%) with two-year survival at 62% (95% CI 48% to 76%). Five-year disease-free survival was 26.7% (95% CI 17 to 52%) with two-year disease-free survival at 54% (95% CI 40% to 68%). To date, this is the largest UK based study reporting overall and disease-free survival associated with MCC of the head and neck. Half the patients presented late, and surgery was the mainstay of treatment, augmented by adjuvant radiotherapy. There is a need to better stratify patients at risk of developing metastatic disease, with the use of sentinel lymph node biopsy and positron-emission tomography-computed tomography (PET-CT), as immunotherapy and targeted agents are now available to treat advanced disease.

The Health Survey for England in 2020, tracking children’s health for 30 years

Background

Prior to their inclusion in the Health Survey for England (HSE), there was a dearth of information about children's health in England. Official data recorded use of health services and uptake of national programmes such as school vaccinations. Birth cohorts provided longitudinal data, including risk factors and non-clinical measures, but were spaced far apart due to cost. The annual HSE has been tracking child health since 1995 and the health of older adolescents (aged 16-19) since the surveys began in 1991. The survey uses a multi-stage design to deliver a nationally-representative random probability sample of the general population in private households in England. Over 110,000 children aged 0-15, and 16,000 16-19-year olds have been interviewed since 1995 and 1991 respectively. Questionnaire content has varied, but includes general health and longstanding conditions, smoking and drinking, fruit and vegetable consumption, physical activity, respiratory problems, childhood diabetes, and parental perception of strengths and difficulties. Regular measurements include infant length, height and weight, blood pressure and cotinine levels.

Results

As well as general monitoring overall and across socioeconomic groups, e.g. height, weight and obesity, HSE data have been used to infer the impact of government policies on child- and adolescent-health, e.g. changes to smoking legal age, advertising, and the smokefree law. This presentation describes in more detail the sample, measurement protocols, questionnaire, published results and research-policy case studies such as the smoking ban. Novel results using the full sample as a synthetic cohort, tracking BMI, smoking, drinking, and general health, are presented for the first time.

Conclusions

Child health monitoring, in terms of trends, inequalities and policy evaluation; is enhanced by regular surveys representative of the general population, which include both subjective and objective measures.

Rapid Identification of Biallelic SPTB Mutation in a Neonate with Severe Congenital Hemolytic Anemia and Liver Failure

Heterozygous pathogenic variants in SPTB cause autosomal dominant hereditary spherocytosis, an important cause of neonatal nonimmune hemolytic anemia. Biallelic mutations are rarely reported, all with severe neonatal presentation. We describe rapid (68 h) genomic diagnosis of homozygous β-spectrin deficiency in a newborn with severe transfusion-dependent hemolytic anemia, conjugated hyperbilirubinemia, and progressive liver failure. Trio whole-exome sequencing identified a novel biallelic SPTB variant (c.6119C>T; p.Thr2040Ile) located in the critical spectrin repeat region. Pretransfusion blood film showed marked spherocytosis including microspherocytes and nucleated erythrocytes, and eosin-5-maleimide (E5M) staining was markedly reduced, supporting pathogenicity. Both asymptomatic heterozygous parents demonstrated mildly reduced E5M staining, with occasional spherocytes and elliptocytes. Early molecular diagnosis facilitated hypertransfusion to suppress ineffective erythropoiesis and reverse hepatic dysfunction. This report broadens the genotypic and phenotypic spectrum of spectrin deficiency and highlights the utility of rapid genomic testing in facilitating early diagnosis and informing targeted therapy in critically ill patients.

Diagnostic and service impact of genomic testing technologies in a neonatal intensive care unit

AIM

To investigate the diagnostic and service impact of chromosomal microarray and whole exome sequencing (WES) in a neonatal intensive care unit (NICU).

METHODS

This was a retrospective medical record review of NICU patients referred for genetics consultation at three time points over a 9-year period at a single centre to determine referral indications, genetic consultation outcomes and time to diagnosis.

RESULTS

The number of NICU patients referred for genetics consultation increased from 44 in 2007 to 95 in 2015. The proportion of NICU patients suspected of having a genetic condition following clinical geneticist assessment remained stable, averaging 5.3% of all admissions. The proportion of patients receiving a confirmed diagnosis rose from 21% in 2007 to 53% in 2015, with a shift from primarily chromosomal abnormalities to a broad range of monogenic disorders, increasingly diagnosed by WES as a first-tier test. The average age at diagnosis in 2015 was 19 days (range 12-38 days) for chromosomal abnormalities and 138 days (range 10-309 days) for monogenic conditions.

CONCLUSIONS

The adoption of new genetic technologies at our centre has increased the proportion of patients receiving a confirmed genetic diagnosis. This study provides important benchmark data to measure further improvements as turn-around times for genomic testing decrease.

Neonatal oesophageal perforation: The role for non-operative management

AIM

Isolated oesophageal perforation in neonates is a rare but potentially life-threatening condition. Although management has historically been operative, conservative management (antibiotics, bowel rest, parenteral nutrition) is now more routinely used. The aim of this study was to evaluate the management of this condition in two large neonatal surgical centres.

METHODS

A retrospective cohort study was conducted for neonates admitted to The Hospital for Sick Children (Toronto, Canada) or The Royal Children's Hospital (Melbourne, Australia) with a diagnosis of oesophageal perforation, from 2006 to 2016. Patients with oesophageal atresia or tracheo-oesophageal fistula were excluded. Data were collected from chart review regarding demographics, clinical course, management and outcomes.

RESULTS

Eleven neonates with oesophageal perforation were identified over a 10-year period at the two centres. Median gestational age at birth was 25.3 weeks (interquartile range 24.2-28.8) and the majority (7/11, 64%) of neonates were extremely low birthweight. Diagnosis was made on day 1 of life for 9 of 11 (81%) neonates and was secondary to nasogastric tube insertion in 10 of 11 (91%) neonates. Only four (36%) neonates had symptomatic complications. All neonates were managed with bowel rest and intravenous antibiotics for a median of 7 days (interquartile range 7-10); two patients required operative intervention. Three neonates (27%) developed chronic lung disease and two (19%) died prior to discharge.

CONCLUSIONS

Oesophageal perforation is severe complication secondary to instrumentation of the upper gastrointestinal tract in neonates. Prompt and accurate diagnosis is crucial. Non-operative management is effective for the majority, though morbidity is common.

What influences children's conceptualizations of language input?

PURPOSE

Children learning language conceptualize the nature of input they receive in ways that allow them to understand and construct utterances they have never heard before. This study was designed to illuminate the types of information children with and without specific language impairment (SLI) focus on to develop their conceptualizations and whether they can rapidly shift their initial conceptualizations if provided with additional input.

METHOD

In 2 studies, preschool children with and without SLI were exposed to an artificial language, the characteristics of which allowed for various types of conceptualizations about its fundamental properties. After being familiarized with the language, children were asked to judge test strings that conformed to the input in 1 of 4 different ways.

RESULTS

All children preferred test items that reflected a narrow conceptualization of the input (i.e., items most like those heard during familiarization). Children showed a strong preference for phonology as a defining property of the artificial language. Restructuring the input to the child could induce them to track word order information as well.

CONCLUSION

Children tend toward narrow conceptualizations of language input, but the nature of their conceptualizations can be influenced by the nature of the input they receive.

Evaluation of stroke early supported discharge services. Collaborative Leadership in Applied Health Research and Care (CLAHRC), Nottinghamshire, Derbyshire and Lincolnshire, UK

A Cochrane systematic review showed that Early Supported Discharge (ESD) following a stroke is both a safe and cost-effective alternative to continued in-patient management. Currently it is unclear whether the health and cost benefits established in the research literature still apply when ESD services are implemented in practice. Our study aims to evaluate the implementation of stroke ESD across three counties in the UK (Nottinghamshire, Derbyshire, Lincolnshire), and offers an innovative approach to facilitate the translation of stroke rehabilitation research into clinical practice.

Phase one of our study was to establish the key components of a successful ESD team based on the research literature. We used a modified Delphi approach with ten ESD trialists, who contributed to the Cochrane review, to produce a consensus document. This provides core guidelines for the implementation of an evidence-based ESD service.

The second ongoing phase of our study involves the evaluation of ESD services in practice. The evaluation looks at changes in patients’ functionality over time, using a range of standardised questionnaires and robust statistical analysis. Such methods can be used by ESD teams in evaluating their effectiveness.

Designing an evaluation of an established ESD team has raised some important methodological issues; these include the variability in the length of hospital stay prior to referral to ESD when compared to trials in the Cochrane review, and the subsequent difficulty in defining the optimal baseline time to consent patients.

The findings from our research will help inform the implementation and delivery of evidence based ESD services in the UK and abroad.

Understanding the role of the stroke physician in early supported discharge services. Collaborative Leadership in Applied Health rRsearch and Care (CLAHRC), Nottinghamshire, Derbyshire and Lincolnshire, UK

Our recent research, using expert consensus with trialists who had contributed to the Cochrane systematic review, has helped to establish key components of effective Stroke Early Supported Discharge (ESD) services. One essential element is that the ESD multidisciplinary team should have access to specialist stroke knowledge. However, how this is organised and put into working practice is less well-defined.

The current qualitative phase of our study investigates such questions about ESD team composition and roles.

The stroke physician’s (SP) involvement may start with commissioning and strategic representation of the service. The SP can then be pivotal to the early identification of eligible patients, and ensuring their medical stability prior to transfer. Within the ESD multidisciplinary team, the SP role includes goal review, goal setting, and giving specialist medical guidance. By providing reassurance to the team on their choice of actions, the SP may also help avoid hospital readmission. Another key component of the SP role has been informal and formal education for the ESD team, on such issues as secondary prevention, and common medical problems post stroke. Finally, SP liaison with the acute stroke team, other hospital specialists and primary care physicians facilitates successful cross-boundary working and can aid patient adherence to secondary prevention measures.

These preliminary findings and experiences suggest that the SP role is critical to effective ESD functioning, and may also offer some useful insights into how to cultivate an integrated and co-ordinated care system for stroke patients.

Successful implementation of stroke early supported discharge services. Collaborative leadership in applied health research and care (CLAHRC), Nottinghamshire, Derbyshire and Lincolnshire, UK

A Cochrane systematic review demonstrated that ESD services can reduce long-term dependency and admission to institutional care as well as reducing the length of hospital stay. No adverse impact on the mood or well-being of patients or carers was reported. This ongoing study aims to facilitate and evaluate the successful implementation of Stroke Early Supported Discharge (ESD) services across Nottinghamshire, Derbyshire and Lincolnshire, UK. This study is being conducted to ensure that the health and cost benefits are still in evidence when ESD services are implemented into local areas.

We have conducted a modified Delphi technique with ESD trialists to reach expert consensus on the component parts of a successful ESD service. We have created an ESD consensus document that can be used by commissioners and service providers in implementing evidence-based ESD services. We are currently evaluating whether benefits of ESD outlined in the research literature are evident in practice. Stakeholder interviews and qualitative research techniques are being used to investigate approaches and models used to implement ESD services. We are also evaluating activities of daily living, mood and quality of life of patients who are admitted to ESD services and eligible patients who are not. Cost effectiveness data are also being captured.

The findings from our research will help inform the setup and delivery of evidence-based ESD services in the UK and abroad.

Development and validation of self-reported line drawings for assessment of knee malalignment and foot rotation: a cross-sectional comparative study

Background

For large scale epidemiological studies clinical assessments and radiographs can be impractical and expensive to apply to more than just a sample of the population examined. The study objectives were to develop and validate two novel instruments for self-reported knee malalignment and foot rotation suitable for use in questionnaire studies of knee pain and osteoarthritis.

Methods

Two sets of line drawings were developed using similar methodology. Each instrument consisted of an explanatory question followed by a set of drawings showing straight alignment, then two each at 7.5° angulation and 15° angulation in the varus/valgus (knee) and inward/outward (foot) directions. Forty one participants undertaking a community study completed the instruments on two occasions. Participants were assessed once by a blinded expert clinical observer with demonstrated excellent reproducibility. Validity was assessed by sensitivity, specificity and likelihood ratio (LR) using the observer as the reference standard. Reliability was assessed using weighted kappa (κ). Knee malalignment was measured on 400 knee radiographs. General linear model was used to assess for the presence of a linear increase in knee alignment angle (measured medially) from self-reported severe varus to mild varus, straight, mild valgus and severe valgus deformity.

Results

Observer reproducibility (κ) was 0.89 and 0.81 for the knee malalignment and foot rotation instruments respectively. Self-reported participant reproducibility was also good for the knee (κ 0.73) and foot (κ 0.87) instruments. Validity was excellent for the knee malalignment instrument, with a sensitivity of 0.74 (95%CI 0.54, 0.93) and specificity of 0.97 (95%CI 0.94, 1.00). Similarly the foot rotation instrument was also found to have high sensitivity (0.92, 95%CI 0.83, 1.01) and specificity (0.96, 95%CI 0.93, 1.00). The knee alignment angle increased progressively from self reported severe varus to mild varus, straight, mild valgus and severe valgus knee malalignment (p_trend <0.001).

Conclusions

The two novel instruments appear to provide a valid and reliable assessment of self-reported knee malalignment and foot rotation, and may have a practical use in epidemiological studies.

Triad of tracheoesophageal fistula-esophageal atresia, pulmonary hypoplasia, and duodenal atresia

We describe 3 cases of tracheoesophageal fistula with esophageal atresia who also had right pulmonary hypoplasia-aplasia and duodenal atresia. We review the current literature and propose that this may be a distinct association.

Clinical features and diagnosis of 42 travellers with cutaneous leishmaniasis

BACKGROUND

Leishmania species that occur within different geographical areas may cause different clinical manifestations, virulence and drug sensitivity. Patients/Methods. All patients with a clinical diagnosis of cutaneous leishmaniasis seen at the Hospital for Tropical Diseases from 1997 to 2000 were identified and clinical details recorded onto a database, with emphasis on clinical presentation, risk factors, travel history and laboratory diagnosis.

RESULTS

Forty-two patients were identified, 23 of whom had travelled to New World and 19 to Old World countries. Clinical presentation typically consisted of a single nodule with ulceration. In 50% infection was caused by L. (Viannia) braziliensis. PCR was performed in specimens from 34 patients and species identification was possible in 32 cases (sensitivity 94%), the two PCR negative patients had amastigotes demonstrated by histology and culture. Patients were treated with established therapies. Seventy one percent were cured by treatment, 12% had a spontaneous cure, 7% were lost to follow-up and the remaining 10% required a second-line therapy. No relapses were reported during a mean follow-up period of 27 months.

CONCLUSIONS

Our study highlights the need for comprehensive investigations and the advantages of PCR in the diagnosis of patients with suspected leishmaniasis in non-endemic regions of the world.

Cerebral white matter hyperintense lesions are associated with unstable carotid plaques

OBJECTIVES

The aim of this study was to determine whether unstable carotid plaques, a known risk factor for cerebral emboli, are associated with cerebral white matter lesions.

METHODS

Seventy-one symptomatic patients undergoing magnetic resonance imaging prior to carotid endarterectomy for high grade carotid stenosis were included in this study. The number and volume of white matter hyperintense lesions (WMHL) on fluid attenuated inversion recovery brain scans were compared according to the morphology of carotid plaque based upon the American Heart Association (AHA) histological classification.

RESULTS

Of the 57 patients who had good quality brain scans and non-fragmented carotid plaques, 15 plaques were defined as stable (type V) and 42 as unstable (type VI). After adjustment for the major risk factors affecting WMHL, unstable carotid plaques were found to be associated with more WMHL in the ipsilateral cerebral hemisphere than stable plaques (transformed means 2.50+/-1.2 vs. 1.53+/-1.1, p=0.016), however, there was only a trend towards larger WMHL volumes (p=0.079).

CONCLUSIONS

The observed association between unstable carotid plaques and the number of white matter lesions suggest that thromboembolic plaque activity may contribute to the development of leukoaraiosis, in particular smaller individual lesions. Larger studies are warranted to confirm this finding and explore the potential clinical impact for selecting candidates for carotid endarterectomy.

Venous Thromboembolism After Acute Ischemic Stroke

Background and Purpose— We prospectively evaluated the prevalence and clinical risk factors for venous thromboembolism (VTE) after acute ischemic stroke using magnetic resonance direct thrombus imaging, a highly accurate noninvasive technique that directly visualizes thrombus.

Method—102 unselected patients with AIS receiving standard prophylaxis with aspirin and graded compression stockings (GCS) were sequentially recruited, underwent regular clinical assessments, and were screened for VTE.

Results— The prevalence of all VTE, proximal deep vein thrombosis (PDVT), and pulmonary embolism (PE) after 21 days were 40%, 18%, and 12%, increasing to 63%, 30%, and 20% in patients with Barthel indices (BI) of ≤9 2 days after stroke (BI-2≤9). Clinical deep vein thrombosis and PE occurred in 3% and 5% overall; half these events were overlooked by the attending team. The true incidence of clinical events is probably higher because the natural history of subclinical PDVT was modified by screening and anticoagulation. BI-2≤9 or nonambulatory status 2 days after stroke were the clinical factors most strongly associated with subsequent VTE on univariate analysis. Odds ratios for any VTE and PDVT for BI-2≤9 versus >9 were 8.3 (95% CI, 2.7 to 25.2) and 8.1 (95% CI, 1.7 to 38.3) on multivariable analysis.

Conclusion— BI ≤9 or nonambulatory status around the time of admission identifies a subgroup of acute ischemic stroke patients at very high risk for VTE in whom the current strategy of thromboprophylaxis may be inadequate. Future thromboprophylactic studies should focus on the patients at high risk defined in this study.

Screening for proximal deep vein thrombosis after acute ischemic stroke: a prospective study using clinical factors and plasma D-dimers

Deep vein thrombosis (DVT) remains common in patients with acute ischemic stroke (AIS) receiving aspirin and graded compression stockings (considered standard thromboprophylaxis in the UK), most events occurring in patients with Barthel indices (BI) of <9 ('severe stroke') around the time of admission. In the absence of data indicating improved clinical outcomes with use of low-dose anticoagulant thromboprophylaxis, we evaluated the hypothesis that plasma D-dimers (D-d) might be a valuable initial screening test for proximal DVT (PDVT), facilitating selective use of imaging. One hundred and two unselected AIS-patients receiving aspirin/graded compression stockings thromboprophylaxis were screened for DVT using magnetic resonance direct thrombus imaging, a highly accurate non-invasive technique which directly visualizes thrombus. D-d (VIDAS and IL test D-d assays) were measured on recruitment and at weekly intervals. Median D-d were significantly higher throughout the study in patients with severe stroke who developed PDVT vs. those with severe stroke not developing PDVT, differences being most marked around day 9. Depending on the discriminatory threshold used, a single D-d measurement at this time in patients with severe-AIS allowed identification of a subgroup with ~50% prevalence of PDVT. Sensitivity of these strategies for PDVT was 67-83%, at a cost of imaging 22-30% of the entire cohort of patients. A single measurement of BI around the time of admission and D-d level at day 9 in AIS-patients receiving aspirin/graded compression stockings thromboprophylaxis allows identification of a subgroup containing a substantial proportion of all PDVTs who could be selectively imaged.

Dehydration and venous thromboembolism after acute stroke

BACKGROUND

Although it is widely assumed that dehydration predisposes to venous thromboembolism (VTE), there are no clinical studies to support this.

AIM

To evaluate the relationship between biochemical indices of dehydration and VTE after acute ischaemic stroke (AIS).

DESIGN

Prospective observational study.

METHODS

Unselected AIS patients (n = 102) receiving standard thromboprophylaxis with aspirin and graded compression stockings, underwent serial measurements of serum urea, creatinine and osmolality, and were screened for VTE using magnetic resonance direct thrombus imaging.

RESULTS

Serum osmolality of >297 mOsm/kg, urea >7.5 mmol/l and urea:creatinine ratio (mmol:mmol) >80 a few days post-AIS were associated with odds ratios for VTE of, respectively, 4.7, 2.8 and 3.4 (p = 0.02, 0.05, 0.02) on multivariable analysis.

DISCUSSION

Dehydration after AIS is strongly independently associated with VTE, reinforcing the importance of maintaining adequate hydration in these patients.

External quality assessment schemes raise standards: evidence from the UKNEQAS parasitology subschemes

BACKGROUND

The burden of parasitic disease imported into the temperate zone is increasing, and in the tropics remains very high. Thus, high quality diagnostic parasitology services are needed, but to implement clinical governance a measure of quality of service is required.

AIM

To examine performance in the United Kingdom National External Quality Assessment Scheme for Parasitology for evidence of improved standards in parasite diagnosis in clinical specimens.

METHODS

Analysis of performance was made for the period 1986 to 2001, to look for trends in performance scores.

RESULTS

An overall rise in performance in faecal and blood parasitology schemes was found from 1986 to 2001. This was seen particularly in the identification of ova, cysts, and larvae in the faecal scheme, the detection of Plasmodium ovale and Plasmodium vivax in the blood scheme, and also in the correct identification of non-malarial blood parasites. Despite this improvement, there are still problems. In the faecal scheme, participants still experience difficulty in recognising small protozoan cysts, differentiating vegetable matter from cysts, and detecting ova and cysts when more than one species is present. In the blood scheme, participants have problems in identifying mixed malarial infections, distinguishing between P ovale and P vivax, and estimating the percentage parasitaemia. The reasons underlying these problems have been identified via the educational part of the scheme, and have been dealt with by distributing teaching sheets and undertaking practical sessions.

CONCLUSIONS

UK NEQAS for Parasitology has helped to raise the standard of diagnostic parasitology in the UK.

Genetic variation at the chromosome 16 chemokine gene cluster: development of a strategy for association studies in complex disease

The chemokine gene cluster [CCL22, CX3CL1, CCL17] (previously known as [SCYA22, SCYD1, SCYA17]) is a candidate locus for one of the susceptibility genes for inflammatory bowel disease that are located in the peri-centromeric region of chromosome 16. Screening for sequence variation at this locus led to the detection of 14 single nucleotide polymorphisms (SNPs). An efficient experimental and computational approach was developed to estimate allele frequencies and pairwise linkage disequilibrium relationships between SNPs at this locus, and to test them for association with inflammatory bowel disease. The 12 common SNPs were assigned to 5 distinct linkage disequilibrium groups. Genotyping of one SNP from each linkage disequilibrium group in a large cohort of families with inflammatory bowel disease did not provide convincing evidence of association with either Crohn's disease or ulcerative colitis. We describe an efficient experimental design from SNP screening to association testing. This strategy can be used to test candidate genes for involvement in susceptibility to complex disease.

Genetic variation in the IGSF6 gene and lack of association with inflammatory bowel disease

The immunoglobulin superfamily 6 gene (IGSF6) on chromosome 16p11-p12 has been investigated as a positional and functional candidate for inflammatory bowel disease (IBD) susceptibility. Screening of the six exons of IGSF6 for single nucleotide polymorphisms (SNPs) detected four novel SNPs, and validated three of six SNPs listed in the international SNP database (dbSNP). The seven SNPs in IGSF6 formed five distinct linkage disequilibrium groups. There was no evidence for association of the common SNPs with disease in a large cohort of patients with IBD. The novel SNPs and the linkage disequilibrium map will be a useful resource for the analysis of IGSF6 in other immune disorders.

Peroxidase enzyme sensor for on-line monitoring of disinfection processes in the food industry

For desirable environmental reasons, peroxides have replaced halogenated substances for disinfection purposes in the food and beverage industry. However, cost issues and the requirement to remove these agents completely after disinfection necessitate simple, low-cost and sensitive test methods with a wide dynamic range and on-line capability. The development and performance of such a method is detailed here. Low-cost peroxide sensors were fabricated using a single deposition procedure, in which horseradish peroxidase enzyme and dimethylferrocene mediator were entrapped within a cellulose acetate membrane, over the working electrode area of a screen-printed three-electrode assembly. Optimum performance was obtained using HRP and DMFc loadings of 25 U and 0.03 micromol per electrode, respectively, and a mean cellulose acetate molecular weight of 37,000. The device had a detection limit of 49.5 microM hydrogen peroxide and mean RSD values of 21% across the concentration range 49.5-368 microM. In laboratory studies the sensor was shown to have a stability of > or = 4 d in continuous flow-mode maintaining an accuracy of +/- 16% that was considered acceptable for the intended on-line monitoring of the disinfection process. In a field study, it was successfully used on-line within a flow-cell to measure peroxide levels during disinfection of an industrial fermentation vessel.

Spirometric lung volumes in the adult Pacific Islander population: comparison with predicted values in a European population

OBJECTIVE

Prediction equations for spirometric lung volumes have been developed mainly in Europe and North America and may not be relevant to Pacific Islanders. This study was undertaken to determine whether currently available prediction equations adequately describe spirometric lung volumes in the asymptomatic adult Pacific Islander population.

METHODOLOGY

Healthy asymptomatic Pacific Island adults aged 15-70 years were recruited. Pulmonary function was measured in the laboratory at Green Lane Hospital, Auckland, New Zealand, in accordance with American Thoracic Society standards. Measured results were compared with predicted values derived from four sets of prediction equations relevant to, or currently used in, New Zealand.

RESULTS

A total of 101 volunteers took part in the study; mean age 28 years (range 18-66 years), 39% male, body mass index = 32 (range 22-54). For forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), when measured values were compared with reference values, the slopes of the regression lines were not significantly different from 1 and the intercepts were not significantly different from zero. Prediction equations derived for African-Americans did not provide a better fit than the prediction equations for Caucasians. Predictions were improved when ideal rather than actual bodyweight was used.

CONCLUSION

Respiratory parameters (FEV1 and FVC) in healthy asymptomatic adult Pacific Islanders in New Zealand are adequately described by currently available prediction equations and no adjustment for ethnicity is required.

Clinical experience with the negative pressure wound dressing

Between 1997 and 1999, more than 300 patients have been treated using negative pressure wound dressings. The technique has been used successfully to prepare various acute, chronic or infected wounds to accept a skin graft or flap, and to promote graft take at difficult donor sites. The advantages include rapid healing by secondary intention, reduced time to skin grafting, an increase in the rate of graft take and a reduction in donor site complications. The dressing can be applied quickly and easily and there have been no serious complications.

Negative pressure wound dressing of the radial forearm donor site

Donor site complications of the radial forearm are a significant cause of post-operative morbidity. 15 patients had radial forearm free tissue donor sites treated with split skin grafts and a negative pressure dressing. All grafts showed 100% take at 5 days. The advantages of this technique include rapid healing at an unfavourable graft recipient site, increased graft take and decreased donor site complications. This method is ideally suited for the management of large defects. The dressing can be quickly and easily applied and there have been no significant complications.

Performance of the OptiMAL malaria antigen capture dipstick for malaria diagnosis and treatment monitoring at the Hospital for Tropical Diseases, London

We report here the sensitivity and specificity of OptiMAL for the diagnosis of acute malaria in patients presenting to the Hospital for Tropical Diseases (HTD), a tertiary referral centre for Tropical and Infectious diseases. A sensitivity of 95.3% and a specificity of 100% for Plasmodium falciparum and a sensitivity of 96% and a specificity of 100% for Plasmodium vivax was obtained. The ability to follow the course of the parasitaemia using OptiMAL during treatment and its significance for use in areas where expert microscopy is not available is discussed.

Increased nitric oxide production in the respiratory tract in asymptomatic pacific islanders: an association with skin prick reactivity to house dust mite

BACKGROUND

Exhaled nitric oxide (NO) is increased in asthma and may also be increased in subclinical airway inflammation. The relationship between atopy and subclinical airway inflammation in the pathogenesis of asthma remains unclear. We have evaluated the relationship between exhaled NO levels and skin prick test reactivity to 8 common allergens in 64 asymptomatic adult Pacific Islanders. Pacific Islanders were studied as a racial group with major morbidity from asthma.

OBJECTIVE

Our purpose was to determine whether asymptomatic subjects with skin prick test reactivity to common allergens have elevated NO levels.

METHODS

All subjects underwent full lung function testing and skin prick testing. Exhaled and nasal NO levels were measured by chemiluminescence (Logan LR2000 analyzer) with use of the single-breath and breath-holding techniques, respectively.

RESULTS

House dust mite (HDM) reactivity was seen in 38 of 64 (56%). Exhaled NO levels (median 8.9 ppb, range 2.9-47.3 ppb) and nasal NO levels (527.5 +/- 181.5 ppb) lay above the normal European range in 30% and 25% of subjects, respectively. HDM reactivity was associated with higher exhaled NO levels (P <. 0005) and higher nasal NO levels (P =.01). In HDM-sensitive subjects the wheal size for HDM correlated with exhaled NO levels (r = 0.35, P =.04) and nasal NO levels (r = 0.40, P =.01). On multivariate analysis, exhaled NO levels were independently and positively related to the severity of HDM reactivity (P =.01) and nasal NO levels (P <.02), equation R(2) = 0.27.

CONCLUSION

NO levels are elevated in a significant proportion of asymptomatic Pacific Islanders and are associated with HDM sensitivity. This may denote subclinical airway inflammation in this population and suggests that exposure to HDM in atopic individuals might play an important role in the early pathogenesis of asthma.

Measuring infectious bursal disease virus RNA in blood by multiplex real-time quantitative RT-PCR

A quantitative reverse transcription polymerase chain reaction (RT-PCR) protocol for assessing infectious bursal disease virus (IBDV) RNA levels in blood was developed using the ABI PRISM 7700 Sequence Detection System coupled with TaqMan chemistry. To control for variations in sampling and processing between samples 28S rRNA was co-amplified in a multiplex reaction and used to quantify total RNA. Relative quantification and standardisation was achieved using a log10 dilution series of RNA extracted from IBDV stock. A linear relationship was observed between input RNA and cycle threshold values (C(T)) over 5 log10 dilutions for the IBDV-specific product and 6 log10 dilutions for the 28S rRNA-specific product. As a test of the assay it was used to determine whether differences in susceptibility to IBDV observed between inbred lines of chickens could be detected at the level of viral load in the blood. Viral RNA levels peaked 2 days post-infection when there was significantly less viral RNA in the blood of resistant line 6(1) chickens compared with the more susceptible Brown Leghorns (P = 0.01). These results demonstrate that the course of IBDV infection can be monitored by quantifying IBDV RNA extracted from blood of infected chickens using TaqMan technology.