Body mass index and survival in people with heart failure

Background

People with obesity are twice as likely to develop heart failure (HF) compared to people with a healthy body mass index (BMI) [1]. However, among people with HF a higher BMI has been linked to a reduced risk of all-cause mortality, a concept known as the “obesity paradox” [2].

Purpose

To examine the association between BMI and survival in patients with chronic HF among a large primary care cohort.

Methods

We extracted data from the Clinical Practice Research Datalink of primary care records from 1st January 2000 to 31st December 2017 and included 47,531 patients with an incident diagnosis of HF, who were aged 45 years and over and who had a recorded BMI. Patients were stratified into categories of baseline BMI as underweight (BMI <18.5 kg/m2), healthy weight (BMI 18.5 to 24.9 kg/m2), overweight (BMI 25.0 to 29.9 kg/m2) or obese, with obesity split into class I (30.0–34.9 kg/m2), class II (35.0–39.9 kg/m2) and class III (40 kg/m2 and over). The primary outcome was all-cause mortality. We used Kaplan-Meier curves and log rank tests to compare survival in people with HF, based on baseline BMI. We also report a Cox regression model for risk of all-cause mortality among people with HF comparing BMI categories.

Results

There were 25,013 deaths during the study follow-up. The average age of participants was 77.1 years (SD 10.6) and mean BMI was 27.9 (SD 6.1). In an age- and sex-adjusted analysis, people who were underweight were at increased risk of all-cause mortality compared to people with healthy weight (HR 1.52, 95% CI 1.41 to 1.64). People with overweight (HR 0.81, 95% CI 0.79 to 0.84), obesity class I (HR 0.79, 95% CI 0.76 to 0.82) and obesity class II (HR 0.78, 95% CI 0.74 to 0.82) were at decreased risk of all-cause mortality. People with obesity class III had no difference in risk of death compared to people with healthy weight (HR 0.95, 95% CI 0.88 to 1.02). In a Kaplan-Meier analysis, there was an inverse relationship between body weight and risk of death, even within the first year of follow-up.

Conclusion

In our large community cohort of people with HF, we found an inverse relationship between BMI and survival. Underweight people with HF have the poorest prognosis and should be identified as high-risk. Conversely, people with HF who are overweight or obese (class I and II) are at lower risk of death confirming the obesity paradox in a real-world primary care population. These findings suggest a more cautious approach to weight management in overweight and obese patients may be needed for people with HF in primary care.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The SurviveHF study was funded by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) Oxford at Oxford Health NHS Foundation Trust and the Wellcome Institutional Strategic Fund. The funders did not have any role in the design of the study, analysis and interpretation of the data, or writing of the results for publication.

Survival among people with heart failure and atrial fibrillation; a population cohort study

Background

People with chronic heart failure (HF) have a poor prognosis, with survival rates at five year follow-up close to 50%.1 More than half of patients with HF will develop atrial fibrillation (AF). The presence of AF in people with HF has been associated with a poor prognosis, irrespective of left ventricular ejection fraction. 2,3 However, the majority of studies to date have analysed prognosis among secondary care cohorts or randomised trial participants, who may not be representative of patients with chronic HF in the community.2

Purpose

To examine the association between survival in patients with HF and AF compared to either condition alone, among a large primary care cohort.

Methods

We extracted data from the Clinical Practice Research Datalink of primary care records from 1st January 2000 to 31st December 2018 and included all patients aged 45 years and over who were registered at an up-to-standard practice for a minimum of 12 months. Records were linked to Hospital Episode Statistics for secondary care data. The primary outcome was all-cause mortality. Exposure groups were defined as HF+AF, HF or AF, with exposure status treated as a time-varying covariate across follow-up. We used Cumulative Hazard plots to compare survival in people with HF and AF, compared to people with either condition alone or neither. We also report a Cox regression model for risk of all-cause mortality among people with HF and AF, adjusting for age, sex, ethnicity, smoking status and comorbid cardiovascular disease.

Results

There were 314,042 deaths during the study follow-up. The average age of participants was 58.0 years (SD 10.6) and 51.4% were women. At some point across follow-up, 94,990 people had HF alone, 147,815 had AF alone and 74,470 had both HF and AF. In an unadjusted Cox regression analysis, people with HF and AF were at the greatest risk of death (HR 17.94, 95% CI 17.75 to 18.13), followed by people with HF alone (HR 12.00, 95% CI 11.87 to 12.13), and AF alone (HR 6.14, 95% CI 6.08 to 6.21) compared to people with neither HF nor AF. In the fully adjusted analysis, the risk of death remained highest among people with HF and AF (HR 3.78, 95% CI 3.73 to 3.83), followed by people with HF alone (HR 3.06, 95% CI 3.02 to 3.10), then people with AF alone (HR 1.85, 95%, CI 1.82 to 1.87). In a cumulative hazard plot, the risk of death across follow-up was similar among people with HF and AF, compared to those with HF alone.

Conclusion

In our large community cohort, we found HF and AF was associated with a worse prognosis than either condition alone. Both HF and AF were also associated with a poor prognosis. These results support the findings of previous secondary care and trial studies regarding the importance of AF as a prognostic indicator among people with HF. Further research could aim to identify preventive strategies that might improve prognosis among this high-risk group of patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The study was undertaken as part of NRJ's Doctoral Research Fellowship, supported by the Wellcome Trust (grant number 203921/Z/16/Z), with additional funding for this project from the National Institute for Health Research (NIHR) Collaboration for Applied Health Research (CLAHRC) Oxford at Oxford Health NHS Foundation Trust (P2-001).

Effectiveness of an online module: climate-change and sustainability in clinical practice

BACKGROUND

Climate change has significant implications for health, yet healthcare provision itself contributes significant greenhouse gas emission. Medical students need to be prepared to address impacts of the changing environment and fulfil a key role in climate mitigation. Here we evaluate the effectiveness of an online module on climate-change and sustainability in clinical practice designed to achieve learning objectives adapted from previously established sustainable healthcare priority learning outcomes.

METHODS

A multi-media, online module was developed, and 3^rd and 4^th year medical students at Brighton and Sussex Medical School were invited to enrol. Students completed pre- and post-module questionnaires consisting of Likert scale and white space answer questions. Quantitative and qualitative analysis of responses was performed.

RESULTS

Forty students enrolled and 33 students completed the module (83% completion rate). There was a significant increase in reported understanding of key concepts related to climate change and sustainability in clinical practice (p < 0.001), with proportion of students indicating good or excellent understanding increasing from between 2 - 21% students to between 91 - 97% students. The majority (97%) of students completed the module within 90 min. All students reported the module was relevant to their training. Thematic analysis of white space responses found students commonly reported they wanted access to more resources related to health and healthcare sustainability, as well as further guidance on how to make practical steps towards reducing the environmental impact within a clinical setting.

CONCLUSION

This is the first study to evaluate learner outcomes of an online module in the field of sustainable health and healthcare. Our results suggest that completion of the module was associated with significant improvement in self-assessed knowledge of key concepts in climate health and sustainability. We hope this approach is followed elsewhere to prepare healthcare staff for impacts of climate change and to support improving the environmental sustainability of healthcare delivery.

TRIAL REGISTRATION

Study registered with Brighton and Sussex Medical School Research Governance and Ethics Committee (BSMS RGEC). Reference: ER/BSMS3576/8, Date: 4/3/2020.

The effect of mental fatigue on the performance of Australian football specific skills amongst amateur athletes

OBJECTIVES

This study investigated the effects of induced mental fatigue on the performance of Australian football (AF) specific skills amongst amateur AF players.

DESIGN

Randomised cross over trial.

METHODS

Twenty-five amateur AF players performed a series of standardised tests from the Australian Football League (AFL) Draft Combine after completing a 30-min Stroop test (mental fatigue condition) or 30-min control condition. The AFL Draft Combine tests included the standing vertical jump test, running vertical jump test, agility test, 20m sprint, Matthew Lloyd clean hands test, Brad Johnson goal kicking test and a Yo-Yo Intermittent Recovery Level 1 (Yo-Yo IR1) test.

RESULTS

The Stroop test score decreased during the Stroop test (first five trials: mean=84.7, SD=3.5; last five trials: mean=82.2, SD=5.0, p=0.03). The Yo-Yo IR1 test (mental fatigue: median=920m, IQR=400; control: median=1040m, IQR=760; p=0.03) and Brad Johnson goalkicking test (mental fatigue: median=19.0, IQR=5.0; control: median=25.0, IQR=10.0, p=0.048) were negatively affected by mental fatigue. No other Draft Combine tests demonstrated a negative affect from mental fatigue.

CONCLUSIONS

Mental fatigue had a detrimental influence on the performance of AF specific skills. The findings may have implications for AF players who are required to sustain attention and concentration for prolonged periods before and during matches.

Adaptive treatment and robust control

A control theory perspective on determination of optimal dynamic treatment regimes is considered. The aim is to adapt statistical methodology that has been developed for medical or other biostatistical applications to incorporate powerful control techniques that have been designed for engineering or other technological problems. Data tend to be sparse and noisy in the biostatistical area and interest has tended to be in statistical inference for treatment effects. In engineering fields, experimental data can be more easily obtained and reproduced and interest is more often in performance and stability of proposed controllers rather than modeling and inference per se. We propose that modeling and estimation should be based on standard statistical techniques but subsequent treatment policy should be obtained from robust control. To bring focus, we concentrate on A-learning methodology as developed in the biostatistical literature and H ∞ -synthesis from control theory. Simulations and two applications demonstrate robustness of the H ∞ strategy compared to standard A-learning in the presence of model misspecification or measurement error.

Radiative Double-Electron Capture by Bare and One-Electron Ions on Gas Targets

Radiative double-electron capture (RDEC) involves the transfer of two electrons with the simultaneous emission of a single photon. This process, which can be viewed as the inverse of double photoionzation, has been studied for 2.11  MeV/u F^{9+} and F^{8+} ions striking gas targets of N_{2} and Ne. The existence of RDEC is conclusively shown for both targets and the results are compared with earlier O^{8+} and F^{9+} findings for thin-foil carbon and with theory. The data for the carbon target showed some evidence for the existence of RDEC, but the interpretation was clouded by high-probability, unavoidable multiple collisions causing the exiting charge state to be increased.

Characterization of isolated liver sinusoidal endothelial cells for liver bioengineering

BACKGROUND

The liver sinusoidal capillaries play a pivotal role in liver regeneration, suggesting they may be beneficial in liver bioengineering. This study isolated mouse liver sinusoidal endothelial cells (LSECs) and determined their ability to form capillary networks in vitro and in vivo for liver tissue engineering purposes.

METHODS AND RESULTS

In vitro LSECs were isolated from adult C57BL/6 mouse livers. Immunofluorescence labelling indicated they were LYVE-1⁺/CD32b⁺/FactorVIII⁺/CD31^-. Scanning electron microscopy of LSECs revealed the presence of characteristic sieve plates at 2 days. LSECs formed tubes and sprouts in the tubulogenesis assay, similar to human microvascular endothelial cells (HMEC); and formed capillaries with lumens when implanted in a porous collagen scaffold in vitro. LSECs were able to form spheroids, and in the spheroid gel sandwich assay produced significantly increased numbers (p = 0.0011) of capillary-like sprouts at 24 h compared to HMEC spheroids. Supernatant from LSEC spheroids demonstrated significantly greater levels of vascular endothelial growth factor-A and C (VEGF-A, VEGF-C) and hepatocyte growth factor (HGF) compared to LSEC monolayers (p = 0.0167; p = 0.0017; and p < 0.0001, respectively), at 2 days, which was maintained to 4 days for HGF (p = 0.0017) and VEGF-A (p = 0.0051). In vivo isolated mouse LSECs were prepared as single cell suspensions of 500,000 cells, or as spheroids of 5000 cells (100 spheroids) and implanted in SCID mouse bilateral vascularized tissue engineering chambers for 2 weeks. Immunohistochemistry identified implanted LSECs forming LYVE-1⁺/CD31^- vessels. In LSEC implanted constructs, overall lymphatic vessel growth was increased (not significantly), whilst host-derived CD31⁺ blood vessel growth increased significantly (p = 0.0127) compared to non-implanted controls. LSEC labelled with the fluorescent tag DiI prior to implantation formed capillaries in vivo and maintained LYVE-1 and CD32b markers to 2 weeks.

CONCLUSION

Isolated mouse LSECs express a panel of vascular-related cell markers and demonstrate substantial vascular capillary-forming ability in vitro and in vivo. Their production of liver growth factors VEGF-A, VEGF-C and HGF enable these cells to exert a growth stimulus post-transplantation on the in vivo host-derived capillary bed, reinforcing their pro-regenerative capabilities for liver tissue engineering studies.

Hypoxic preconditioning of myoblasts implanted in a tissue engineering chamber significantly increases local angiogenesis via upregulation of myoblast vascular endothelial growth factor-A expression and downregulation of miRNA-1, miRNA-206 and angiopoietin-1

Vascularization is a major hurdle for growing three-dimensional tissue engineered constructs. This study investigated the mechanisms involved in hypoxic preconditioning of primary rat myoblasts in vitro and their influence on local angiogenesis postimplantation. Primary rat myoblast cultures were exposed to 90 min hypoxia at <1% oxygen followed by normoxia for 24 h. Real time (RT) polymerase chain reaction evaluation indicated that 90 min hypoxia resulted in significant downregulation of miR-1 and miR-206 (p < 0.05) and angiopoietin-1 (p < 0.05) with upregulation of vascular endothelial growth factor-A (VEGF-A; p < 0.05). The miR-1 and angiopoietin-1 responses remained significantly downregulated after a 24 h rest phase. In addition, direct inhibition of miR-206 in L6 myoblasts caused a significant increase in VEGF-A expression (p < 0.05), further establishing that changes in VEGF-A expression are influenced by miR-206. Of the myogenic genes examined, MyoD was significantly upregulated, only after 24 h rest (p < 0.05). Preconditioned or control myoblasts were implanted with Matrigel™ into isolated bilateral tissue engineering chambers incorporating a flow-through epigastric vascular pedicle in severe combined immunodeficiency mice and the chamber tissue harvested 14 days later. Chambers implanted with preconditioned myoblasts had a significantly increased percentage volume of blood vessels (p = 0.0325) compared with chambers implanted with control myoblasts. Hypoxic preconditioned myoblasts promote vascularization of constructs via VEGF upregulation and downregulation of angiopoietin-1, miR-1 and miR-206. The relatively simple strategy of hypoxic preconditioning of implanted cells - including non-stem cell types - has broad, future applications in tissue engineering of skeletal muscle and other tissues, as a technique to significantly increase implant site angiogenesis.

From breathless to failure: symptom onset and diagnostic meaning in patients with heart failure-a qualitative study

OBJECTIVES

To explore 2 key points in the heart failure diagnostic pathway-symptom onset and diagnostic meaning-from the patient perspective.

DESIGN

Qualitative interview study.

SETTING

Participants were recruited from a secondary care clinic in central England following referral from primary care.

PARTICIPANTS

Over age 55 years with a recent (<1 year) diagnosis of heart failure confirmed by a cardiologist following initial presentation to primary care.

METHODS

Semistructured interviews were carried out with 16 participants (11 men and 5 women, median age 78.5 years) in their own homes. Data were audio-recorded and transcribed. Participants were asked to describe their diagnostic journey from when they first noticed something wrong up to and including the point of diagnosis. Data were analysed using the framework method.

RESULTS

Participants initially normalised symptoms and only sought medical help when daily activities were affected. Failure to realise that anything was wrong led to a delay in help-seeking. Participants' understanding of the term 'heart failure' was variable and 1 participant did not know he had the condition. The term itself caused great anxiety initially but participants learnt to cope with and accept their diagnosis over time.

CONCLUSIONS

Greater public awareness of symptoms and adequate explanation of 'heart failure' as a diagnostic label, or reconsideration of its use, are potential areas of service improvement.

Changes in the severity and subtype of Guillain-Barré syndrome admitted to a specialist Neuromedical ICU over a 25 year period

We report a retrospective review of 110 patients with acute Guillain-Barré syndrome (GBS) admitted to a specialised intensive care unit (ICU) in a tertiary referral centre over a 25 year period, the start of which coincided with the widespread introduction of plasma exchange (PE) and intravenous immunoglobulin (IVIG). The results were analysed by comparing 52 patients admitted in the first decade (1991–2000; Group 1) with 58 patients admitted between 2001–2014 (Group 2). Patients in both groups were comparable with respect to age and sex, and had a similar incidence and range of ICU complications. They received a comparable range of immunomodulatory treatments including IVIG and PE. However, the delay from presentation to referral to the tertiary ICU was longer in patients in Group 2. They also required mechanical ventilation for a longer duration, and had longer ICU and hospital stays. In Group 2, there was a higher incidence of axonal neuropathy (51%, compared to 24% in Group 1). Despite the longer delay to referral, the prevalence of axonal neuropathy and the duration of ventilation, overall mortality showed a downward trend (Group 1: 13.5%; Group 2: 5.2%). There was no late mortality in either group after step-down to neuro-rehabilitation or following discharge home or to the referring hospital. The rehabilitation outcomes were similar. This data show a shift in the pattern of referral to a tertiary referral ICU between the first and second decades following the wider availability of IVIG and PE for the treatment of GBS. The possible causes and implications of these findings are discussed.

"Relational by Nature"? Men and Women Do Not Differ in Physiological Response to Social Stressors Faced by Token Women

Women in male-dominated occupations report negative workplace social climates, whereas most men in female-dominated occupations report positive workplace social climates. Using a laboratory experiment mimicking the negative workplace social climates experienced by these token women, the author examines whether women are more sensitive to negative workplace social climates than men are or if, instead, men and women react similarly. Using salivary cortisol, the author finds that token men and token women are equally likely to exhibit a physiological stress response to social exclusion on the basis of gender. A second experiment shows that token men and token women who are socially included do not exhibit physiological stress response. Findings imply that(1) social exclusion on the basis of gender may be associated with physiological stress response and consequent negative health outcomes and (2) combined social-structural and social-interactional components of token women's workplace climates would be stressors to both men and women workers.

Genomic variation in two gametocyte non-producing Plasmodium falciparum clonal lines

Background

Transmission of the malaria parasite Plasmodium falciparum from humans to the mosquito vector requires differentiation of a sub-population of asexual forms replicating within red blood cells into non-dividing male and female gametocytes. The nature of the molecular mechanism underlying this key differentiation event required for malaria transmission is not fully understood.

Methods

Whole genome sequencing was used to examine the genomic diversity of the gametocyte non-producing 3D7-derived lines F12 and A4. These lines were used in the recent detection of the PF3D7_1222600 locus (encoding PfAP2-G), which acts as a genetic master switch that triggers gametocyte development.

Results

The evolutionary changes from the 3D7 parental strain through its derivatives F12 (culture-passage derived cloned line) and A4 (transgenic cloned line) were identified. The genetic differences including the formation of chimeric var genes are presented.

Conclusion

A genomics resource is provided for the further study of gametocytogenesis or other phenotypes using these parasite lines.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-016-1254-1) contains supplementary material, which is available to authorized users.

Comparison of two pancreatic enzyme products for exocrine insufficiency in patients with cystic fibrosis

BACKGROUND

Zenpep (APT-1008) is a pancreatic enzyme product for the treatment of exocrine pancreatic insufficiency (EPI) associated with cystic fibrosis (CF).

METHODS

Zenpep and Kreon, both containing 25,000 lipase units, were compared in a randomised, double-blind, crossover, non-inferiority study for CF-associated EPI in patients aged ≥12years. Patients on a standardised diet and stabilised treatment were randomised to two treatment sequences: Zenpep/Kreon or Kreon/Zenpep. The primary efficacy endpoint was the coefficient of fat absorption over 72h (CFA-72h).

RESULTS

96 patients (mean age 19.2years, 60.4% males) were randomised with 83 completers of both sequences comprising the efficacy population. Zenpep demonstrated non-inferiority and equivalence to Kreon in fat absorption (LS mean CFA-72h: Zenpep, 84.1% [SE 1.1] vs. Kreon, 85.3% [SE 1.1]; p=0.297). Safety and tolerability were similar.

CONCLUSIONS

Zenpep is comparable with Kreon in efficacy and safety for the treatment of adolescents and adults with CF-associated EPI. NCT01641393.

Transfer of HLA-Specific Allosensitization From a Highly Sensitized Deceased Organ Donor to the Recipients of Each Kidney

We report for the first time the adoptive transfer of donor HLA-specific allosensitization in two recipients following kidney transplantation from a highly sensitized donor. Kidneys from a donation after circulatory death donor were transplanted into two nontransfused, HLA-specific antibody negative males receiving their first transplant. Antibody screening 7 days after transplant showed high level de novo IgG HLA class I- and class II-specific antibodies in both recipients, with largely overlapping antibody profiles but no antibodies to donor HLA. The unusually rapid appearance of de novo alloantibodies in immunosuppressed nonsensitized recipients and absence of donor HLA-specific antibody prompted testing of stored donor serum that revealed high antibody levels with specificities very similar to those seen in both recipients, but in addition the presence of strong antibodies to each recipient HLA. Alloantibody levels gradually declined but were still detectable at 3 months. These findings suggest that alloreactive passenger B cells/plasma cells within the kidneys of highly sensitized donors may give rise to rapid development of posttransplant de novo HLA-specific alloantibodies. While the clinical significance of this phenomenon is uncertain it provides one explanation for the appearance of de novo HLA-specific antibodies directed against third party but not donor HLA.

Should HLA mismatch acceptability for sensitized transplant candidates be determined at the high-resolution rather than the antigen level?

Defining HLA mismatch acceptability of organ transplant donors for sensitized recipients has traditionally been based on serologically defined HLA antigens. Now, however, it is well accepted that HLA antibodies specifically recognize a wide range of epitopes present on HLA antigens and that molecularly defined high resolution alleles corresponding to the same low resolution antigen can possess different epitope repertoires. Hence, determination of HLA compatibility at the allele level represents a more accurate approach to identify suitable donors for sensitized patients. This approach would offer opportunities for increased transplant rates and improved long term graft survivals.

The potential role of NT-proBNP in screening for and predicting prognosis in heart failure: a survival analysis

OBJECTIVE

To determine the potential role of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in screening for and predicting prognosis in heart failure by examining diagnosis and survival of patients with a raised NT-proBNP at screening.

DESIGN

Survival analysis.

SETTING

Prospective substudy of the Echocardiographic Heart of England Screening study (ECHOES) to investigate 10-year survival in participants with an NT-proBNP level at baseline.

PARTICIPANTS

594 participants took part in the substudy. Records of all participants in the ECHOES cohort were flagged during the screening phase which ended on 25 February 1999. All deaths until 25 February 2009 were coded.

OUTCOME MEASURES

Logistic regression was used to examine whether NT-proBNP is useful in predicting heart failure at screening after adjustment for age, sex and cohort. Kaplan-Meier curves and log rank tests were used to compare survival times of participants according to NT-proBNP level. Cox regression was carried out to assess the prognostic effect of NT-proBNP after allowing for significant covariates and receiver operator curves were used to determine test reliability.

RESULTS

The risk of heart failure increased almost 18-fold when NT-proBNP was 150 pg/mL or above (adjusted OR=17.7, 95% CI 4.9 to 63.5). 10-year survival in the general population cohort was 61% (95% CI 48% to 71%) for those with NT-proBNP ≥150 pg/mL and 89% (95% CI 84% to 92%) for those below the cut-off at the time of the initial study. After adjustment for age, sex and risk factors for heart failure, NT-proBNP level ≥150 pg/mL was associated with a 58% increase in the risk of death within 10 years (adjusted HR=1.58, 95% CI 1.09 to 2.30).

CONCLUSIONS

Raised NT-proBNP levels, when screening the general population, are predictive of a diagnosis of heart failure (at a lower threshold than guidelines for diagnosing symptomatic patients) and also predicted reduced survival at 10 years.

Simulating nailfold capillaroscopy sequences to evaluate algorithms for blood flow estimation

The effects of systemic sclerosis (SSc)--a disease of the connective tissue causing blood flow problems that can require amputation of the fingers--can be observed indirectly by imaging the capillaries at the nailfold, though taking quantitative measures such as blood flow to diagnose the disease and monitor its progression is not easy. Optical flow algorithms may be applied, though without ground truth (i.e. known blood flow) it is hard to evaluate their accuracy. We propose an image model that generates realistic capillaroscopy videos with known flow, and use this model to quantify the effect of flow rate, cell density and contrast (among others) on estimated flow. This resource will help researchers to design systems that are robust under real-world conditions.

A comparison of laparoscopic versus open rectal surgery in 114 consecutive octogenarians

AIM

The study is a retrospective review of the short-term outcome of all elective rectal resections in 114 consecutive octogenarian patients during the 10-year period January 2000 to December 2009.

METHOD

Sixty laparoscopic and 54 open resections were completed. The two groups were evenly matched for age (mean 83 years), American Society of Anesthesiologists score (mean 2.5) and pathology (malignancy 60%).

RESULTS

Morbidity and mortality were comparable with no significant differences. Only length of stay in uncomplicated recoveries was significantly different in favour of laparoscopic surgery at 10 vs 14 days, P < 0.003.

CONCLUSION

Laparoscopic rectal resection is suitable for octogenarians.

Activation of latent precursors in the hippocampus is dependent on long-term potentiation

The recent discovery of a large latent population of precursor cells in the dentate gyrus of adult mice led us to investigate whether activation of this population is regulated by synaptic activity, thereby explaining the observation that environmental signals can affect neurogenesis. Using a variety of stimulation protocols, we found that only a long-term potentiation (LTP)-inducing protocol activated the latent precursor pool, leading to increased neurogenesis in the dentate gyrus. LTP induced by high-frequency stimulation (HFS) of the perforant pathway in vivo produced a two-fold increase in the number of neurospheres cultured from the stimulated hippocampus, compared with the unstimulated hippocampus. No increase in neurosphere number or neurogenesis was observed when the HFS failed to induce LTP. These results show that LTP can activate latent neural precursor cells in the adult mouse dentate gyrus, thereby providing a direct mechanism for regulating activity-driven neurogenesis. In the future, it may be possible to utilize such learning- or stimulation-induced neurogenesis to overcome disorders characterized by neuronal loss.

Treatment pathways for patients with atrial fibrillation

BACKGROUND

Although there has been growing concordance over what constitutes best practice in recent guidelines for treatment of atrial fibrillation (AF), notably regarding anticoagulant use, it remains unclear whether patients are being treated accordingly.

AIMS

The aims of this study were to explore the pattern of treatment pathways - i.e. how patients are treated over time - for patients with AF, and to test the hypothesis that comparative to patients in lower stroke-risk categories (as measured by CHADS(2) score), patients with higher CHADS(2) scores are less likely to discontinue anticoagulant therapy or, if not started on anticoagulant treatment, more likely to be transferred to anticoagulant therapy, in keeping with guideline recommendations.

SETTING

A total of 67,857 patients with a diagnosis of AF in practices registered with the General Practice Research Database.

METHODS

A series of possible treatment pathways were identified, and for each initial treatment, we estimated the probability of treatment change and the average time that a patient newly diagnosed with AF spent on a particular treatment, projected across 5 years and stratified by CHADS(2) score.

RESULTS

There was no relationship between CHADS(2) score and maintenance or discontinuation of particular approaches to antithrombotic treatment. While those beginning on antiplatelet therapy were more likely to change treatment than those on anticoagulants (approximately 60% vs. 50% within the first year), as much as one-third of treatment time of all those starting on a therapeutic approach involving anticoagulants featured no use of anticoagulants (either as monotherapy or in combination) over the 5-year period, and whether treatment was discontinued or maintained did not vary by CHADS(2) score. No difference was found in treatment pathways controlling for post-2002 diagnoses as against the whole sample.

CONCLUSIONS

Although there is more evidence of treatment maintenance than treatment change, especially in the first year after diagnosis, the amount of therapeutic change remains noteworthy and appears higher than in some previous studies. Prescription patterns for AF therapy suggest that too few high-risk patients are receiving best practice treatment, and particularly of concern is that some of these patients are being transferred away from best practice treatment over time.

Rhythm control agents and adverse events in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the commonest rhythm disorder and has major impact on patients. Controversy remains about the best treatment strategy between rate and rhythm control (in addition to adequate thromboprophylaxis). Rhythm control agents are associated with clinically important adverse events.

AIM

The aim of this study was to assess the risk of adverse events in patients with AF receiving rhythm control agents.

DESIGN OF STUDY

This is a retrospective case control note review and outcome linkage analysis.

SETTING

Setting of this study included patients with a diagnosis of AF receiving amiodarone, flecainide or sotalol in practices registered with the General Practice Research Database (GPRD) in the UK.

METHOD

This is a retrospective case control note review and outcome linkage analysis on the GPRD routine clinical dataset to evaluate the adverse events and predictors of treatment discontinuation in patients using licenced rhythm modifying medication.

RESULTS

Adverse events are more common in patients currently or previously taking amiodarone, flecainide or sotalol than age- and gender-matched controls. All three antiarrhythmics were associated with increased all-cause mortality. Congestive heart failure was more common in all amiodarone and sotalol users as well as past users of flecainide. Thyroid disease was more common in patients treated with amiodarone and sotalol but only amiodarone had an increased risk of pulmonary toxicity. The number of patients with liver failure was too small in all cases for statistical analysis.

CONCLUSION

The rhythm control agents amiodarone, flecainide and sotalol have significant adverse effects which can lead to discontinuation of their use. This should be considered when deciding the most appropriate treatment option for patients with AF.

Measurement and visualisation of focal cartilage thickness change by MRI in a study of knee osteoarthritis using a novel image analysis tool

We describe the application of a novel analysis method that provides detailed maps of changes in cartilage thickness measured from MRI scans for individuals and cohorts of patients together with regional measures. A cohort of osteoarthritis patients was imaged using a 1.0 T MR scanner over a 36-month period. Hyaline cartilage was manually segmented from a three-dimensional (3D) spoiled gradient-echo sequence with fat suppression. Representative outlines of the bone surfaces of the distal femur and proximal tibia were automatically generated from T₂ weighted images using statistical models of the shape and appearance of the bones. Cartilage thickness was measured from a dense set of points representing the bony surface. The models of the bones provided a common frame of reference, relative to which change maps were generated and aggregated across the cohort and anatomically corresponding subregions of the joint to be identified. In the reproducibility arm involving six patients, the thickness of cartilage had coefficients of variation of 2.66% within the tibiofemoral joint and 2.94% within the medial femoral condyle region. In the 9 patients (6 female, 3 male) who completed the 36-month study, the most striking observation was that lack of change in global measures of cartilage thickness concealed substantial focal changes. Specifically, the cartilage thickness within the tibiofemoral joint decreased by 0.85% per annum (95% CI -2.13% to 0.45%) with the medial femoral condyle as the region with the most significant change, decreasing by 2.43% per annum (uncorrected 95% CI -4.31% to 0.51%).

Small intestinal glucose absorption in cystic fibrosis: a study in human and transgenic ΔF508 cystic fibrosis mouse tissues

Intestinal transport is disturbed in cystic fibrosis (CF), with both defective Cl− secretion and changes in absorption being reported. We have examined the effects of the disease on Na+-dependent glucose absorption by the small intestine. Active glucose absorption was monitored as changes in short-circuit current (SCC) in intact and stripped intestinal sheets from normal (Swiss) and transgenic CF (Cftrtm 1 Eur and Cftrtm 2 Cam) mice with the ΔF508 mutation, and in jejunal biopsies from children with CF and normal controls. Na+-dependent glucose uptake at the luminal membrane was measured in brush-border membrane vesicles (BBMVs). Intact and stripped sheets of jejunum and midintestine from Swiss mice exhibited a concentration-dependent increase in SCC with glucose. Apparent Km values were similar in the two preparations, but the apparent Vmax was greater in stripped sheets. This difference was not due to a loss of neural activity in stripped sheets as tetrodotoxin did not influence the glucose-induced SCC in intact sheets. Similar results were observed in stripped sheets of jejunum and mid-intestine from wild-type Cftrtm 1 Eur mice, but in tissues from CF mice the apparent Vmax value was reduced significantly. A lower Vmax was also obtained in intact sheets of mid-intestine from CF (Cftrtm 2 Cam) mice. Jejunal biopsies from CF patients however, exhibited an enhanced glucose-dependent rise in SCC. Na+-dependent uptake by BBMVs from CF (Cftrtm 1 Eur) mice was not reduced compared with wild-type and Swiss BBMVs. It was concluded that, in contrast to human intestine, intestinal glucose absorption was reduced in transgenic mouse models of CF with the ΔF508 mutation, but that this could not be detected in an isolated preparation of brush-border membranes. Transgenic mouse models of CF may not accurately reflect all aspects of intestinal dysfunction in the human disease.

Physiological measurements confirming the diagnosis of cystic fibrosis: the sweat test and measurements of transepithelial potential difference

Post-natal screening allied with genetic mutation testing has altered our perception of cystic fibrosis (CF) as a clinical entity. Increasingly, infants identified through screening programmes have few or no symptoms or present with atypical forms of the disease. We review how the sweat test has evolved to be the gold standard for confirming the diagnosis of CF and examine its limitations. Other physiological measurements, including nasal potential difference and intestinal current measurement, which might aid in establishing the diagnosis, particularly in patients exhibiting a mild phenotype, are also considered.

Risk of cardiac catheterization under anaesthesia in children with pulmonary hypertension

BACKGROUND

Children with primary pulmonary hypertension (PHT) are a high-risk group who require assessment by cardiac catheterization under anaesthesia. Complications, including death, have occurred during anaesthesia in these patients, but the true risk has not been quantified.

METHODS

The clinical records of children with PHT undergoing general anaesthesia for pulmonary vascular resistance studies were reviewed retrospectively. Data collected included pre-catheter measures of severity of disease, details of clinical management, and complications occurring within 24 h of the start of anaesthesia.

RESULTS

During the past 5 yr, 75 consecutive patients were catheterized and usable records were available in 70. The age range was 0.1-18 yr (mean 7.1). Four children required external cardiac massage [6% (95% confident limits 1-11%)] and one of these died. Of the four, two had an arrhythmia related to the mechanical effects of catheterization, one was hypotensive during anaesthesia and the other had fatal cardiac failure in recovery. All four had severe PHT as judged by echocardiographic estimation of tricuspid regurgitant jet velocity>4 m s-1.

CONCLUSIONS

Resuscitation or death occurred in 6% of cases. Any associated risk factors could not be determined because the number of complications was too small. Risks may be highest in children with severe idiopathic PHT and symptoms of chest pain, syncope, or dizziness.

MR measurement of articular cartilage thickness distribution in the hip

OBJECTIVE

To develop a method to determine the distribution of articular cartilage in the hip and to evaluate the potential of the method in a study of normal weight-bearing effects in asymptomatic young volunteers.

DESIGN

Six volunteers were scanned after periods of standing and lying supine, using 3D gradient-echo magnetic resonance imaging (MRI). The protocol was repeated for two successive weeks to determine reproducibility. The femoral and acetabular cartilage layers were segmented as a single unit and thickness distribution maps were calculated using a spherical bone model as a frame of reference. Thickness maps were combined over the population using the bone model and post-weight-bearing and post-resting maps were compared.

RESULTS

Mean thickness values were compared using an analysis of variance and a significant increase in cartilage thickness of 0.05 mm (P=0.02) was observed. The reproducibility of the method, assessed using test-retest coefficient of variation was 2.5%.

CONCLUSIONS

The technique is reproducible, sensitive to sub-millimetre changes in thickness and may be useful in monitoring changes due to disease progression in patients with arthritis of the hip.

Acute distal biceps tendon rupture--a new surgical technique using a de-tensioning suture to brachialis

Acute distal biceps rupture is a devastating injury in the young athlete and surgical repair offers the only chance of a full recovery. We report a new surgical technique used in 14 cases of acute distal tendon rupture in which the 'suture anchor technique' and a de-tensioning suture was employed. In this procedure the distal end of the biceps is re-attached to the radial tuberosity using a sliding whip stitch suture and the proximal part of the distal tendon repair attached to the underlying brachialis muscle with absorbable sutures. This restores correct anatomical alignment and isometric pull on the distal tendon and de-tensions the repair in the early post-operative period, allowing early rehabilitation and an early return to activity. In all cases patients regained a full pre-injury level of sporting activity at a mean period of 6.2 months (2-9 months).

Functional foods and paediatric gastro-intestinal health and disease

The application of molecular methods to gastro-intestinal diseases is giving insight into the way in which the resident intestinal microbiota interacts with the mucosal immune system. Using traditional culture techniques, the importance of mucosally-associated bacterial biofilms in maintaining mucosal integrity has been demonstrated in ways previously impossible. Changes in the balance of organisms at initiation of and during disease provide a rationale for interventions with functional foods which facilitate re-establishment of the homeostasis of healthy gut.

Pulmonary infection in mild variant cystic fibrosis: implications for care

BACKGROUND

Disease phenotype in cystic fibrosis (CF) shows considerable heterogeneity. Atypical or mild mutations in the CFTR gene have been linked to late-onset pulmonary disease; however, few reports document the condition of the airway in infants and young children with apparent "mild" disease. Prognosis is uncertain in this group of patients and this, in turn, has led to inconsistency in management. Our initial experience of pulmonary infection in children with mild variant CF prompted a more detailed review of clinical outcome.

METHODS

A retrospective cohort study was carried out comparing frequency of bacterial isolates and clinical outcomes in eleven compound heterozygotes for DeltaF508 and a second mild mutation, mainly R117H, with a matched group of DeltaF508 homozygotes.

RESULTS

Staphylococcus aureus was isolated in 8 of the 11 patients with mild variant disease and Pseudomonas aeruginosa found in 7 (64%), although the frequency of positive cultures was significantly less (2.8/year) than the DeltaF508 homozygotes (6.1/year, p<0.05). Shwachman scores (median+range) were significantly higher in patients with mild mutations - 94, 74-92 vs. 88, 77-91; p<0.005); there was also a small but significant difference in chest radiograph (Chrispin-Norman) scores (median+range) (mild 5.1, 4-9, vs. severe 5.8, 3-10; p 0.04). There was little difference in lung function in terms of FEV1 (median+range) between the two groups (% predicted, mild 86.5, 68-87 vs. severe 76.0, 65-88; p 0.5).

CONCLUSIONS

Most patients with mild variant CF will have bacterial isolates from airway cultures requiring antibiotic therapy three to four times a year. Infection with both S. aureus and P. aeruginosa is common. Anti-staphylococcal prophylaxis for the first two years should be considered.

Assessing successful entry into nurse practitioner practice: a literature review

Nurse practitioners (NPs) have been the subjects of many studies focused on role performance, cost effectiveness, and acceptance in clinical practice. As part of a study to compare successful entry of NP program graduates from various backgrounds into NP practice, a review of the literature was performed. This literature review focuses on research studies that examine successful entry into NP practice by seasoned registered nurses as well as by non-nurse college graduates who have no prior nursing experience. The topical areas that emerged from the literature were educational background and experience as a registered nurse, socialization into practice, transition into NP practice, and evaluation measures of successful NP practice. The results of the literature review revealed the need for further work on assessment of successful entry into NP practice.

Donor CD31 genotype and its association with acute graft-versus-host disease in HLA identical sibling stem cell transplantation

CD31 gene polymorphisms are implicated in the pathogenesis of graft-versus-host disease (GvHD) following haematopoietic stem cell transplantation (HST). We investigated the influence of CD31 genotype on the incidence of GvHD following HST from an human leukocyte antigen (HLA)-identical sibling donor. Donor and recipient CD31 codons 125, 563 and 670 DNA polymorphisms were determined in 85 cases of HLA identical sibling HST from two transplant centres. A correlation between CD31 genotype and acute GvHD was considered significant if observed in patients from both transplant centres independently. A strong correlation was identified between donor CD31 codon 125 genotype and the incidence of acute GvHD. Acute GvHD grades II-IV occurred in 27 of 46 (59%) recipients with a CD31 codon 125 leucine / valine heterozygous donor compared to nine of 39 (23%) recipients with a CD31 codon 125 homozygous donor (P=0.0019, relative-risk 2.45, 95% confidence interval 1.3-4.5). This correlation was significant in patients from both transplant centres (P=0.015 and P=0.019). We suggest that CD31 genotype may influence the function of donor-derived leukocytes and may be informative when there is a choice of comparable donors.

Measurement of cartilage volumes in rheumatoid arthritis using MRI

MRI is a valuable imaging modality for assessment of the articular cartilage in rheumatoid arthritis (RA) and is potentially of use in monitoring disease progression and response to therapy. In this study, we investigated the sources of error in volume measurements obtained by segmentation of MR images of knee cartilage in patients with RA and followed cartilage volume in a group of RA patients for 12 months. 23 RA patient volunteers were recruited for knee imaging. Six subjects were imaged at baseline only, six were imaged at baseline and again within an hour in the same imaging session, six subjects were imaged at baseline and 7 days, and 17 subjects were imaged at baseline, 4+/-2 months and 12 months. Imaging was performed at 1.0 T using a three-dimensional spoiled gradient-echo sequence with fat-suppression. Manual image segmentation was performed once or twice on the lateral tibial, medial tibial, patellar and femoral compartment by either one or two segmenters. Coefficients of variation (CoV) for repeated volume measurement of total cartilage were 2.2% (same segmenter, same scan), 5.2% (different segmenter, same scan), 4.9% (same segmenter, different scan, same session), and 4.4% (same segmenter, different scan, different session). Over the 12 month duration of the study there was no significant change in total cartilage volume, nor were there significant changes in volume in any individual compartment. This measurement technique is reproducible, but any net change in cartilage volume over 1 year is very small.

Anatomical statistical models and their role in feature extraction

A detailed model of the shape of anatomical structures can significantly improve the ability to segment such structures from medical images. Statistical models representing the variation of shape and appearance can be constructed from suitably annotated training sets. Such models can be used to synthesize images of anatomy, and to search new images to accurately locate the structures of interest, even in the presence of noise and clutter. In this paper we summarize recent work on constructing and using such models, and demonstrate their application to several domains.

Pilot safety study of liposomal prostaglandin (PGE1) in respiratory exacerbations in cystic fibrosis

BACKGROUND

A pilot evaluation to assess the safety and possible benefits of TLC C-53, (prostaglandin E(1) associated with egg phosphatidylcholine liposomes) in acute respiratory exacerbations in children with cystic fibrosis (CF).

METHODS

Randomised, double-blind, placebo-controlled study in 20 P. aeruginosa colonised patients. All received intravenous antibiotics. Subjects were given a rising dose of TLC C-53 (0.15-1.8 microg/kg) by 4 x 1-h infusions. Primary outcome measures were sputum IL-6, IL-8 and sputum neutrophil elastase. The rate of decline in lung function was determined at 6 weeks post-therapy as was the interval until the next respiratory exacerbation requiring intravenous antibiotic therapy.

RESULTS

Analysis of primary and secondary outcome measures failed to show any significant differences between the two groups, although trends favoured the treated group. Decline in lung function over 6 weeks favoured the TLC C-53 group (FEV(1) mean difference 4.3%, 95% CI=-6.8, 15.4%). Time to next exacerbation also favoured the TLC C-53 group with a mean time to exacerbation for TLC C-53 of 26.0 weeks against 11.9 weeks.

CONCLUSIONS

A larger multi-centre trial of TLC C-53 as an adjunct to antibiotic therapy in respiratory exacerbations in CF would appear warranted.

Absorption of taurocholic acid by the ileum of normal and transgenic DeltaF508 cystic fibrosis mice

Changes in intestinal transport in cystic fibrosis (CF) include both defective Cl(-) secretion and alterations in absorption. This study focused on the effects of CF on the active re-absorption of bile acids in the ileum of normal and transgenic CF mice. Taurocholic acid absorption was monitored as changes in short-circuit current (SCC) in intact and stripped ileal sheets from normal (Swiss) and transgenic CF (Cftr(tm2Cam)) mice with the DeltaF508 mutation. Taurocholic acid uptake was measured directly in everted ileal sacs and in brush-border membrane vesicles (BBMVs) using radiolabelled bile acid. Taurocholic acid caused a biphasic increase in SCC in both intact and stripped ileal sheets from Swiss mice. The initial phase of the response was associated with active bile acid absorption as it was inhibited by a low mucosal Na(+) concentration, but unaffected by Cl(-)-free conditions, serosal furosemide or mucosal diphenylamine-2-carboxylic acid (DPC). The first phase was concentration-dependent and was reduced in the presence of other actively transported bile acids. Intact ileal sheets from wild-type Cftr(tm2Cam) mice also exhibited a biphasic SCC response to taurocholic acid, but in CF tissues the initial phase was reduced and the second phase was absent. Taurocholic acid was actively taken up by everted ileal sacs from Swiss mice. This process was inhibited by a low mucosal Na(+) concentration or the presence of other actively transported bile acids. A similar taurocholic acid uptake was observed in ileal sacs from wild-type mice, but in those from CF mice transport of the bile acid was significantly reduced. However, taurocholic acid uptake was similar in BBMVs from wildtype and CF ilea. Active absorption of taurocholic acid occurs in mouse ileum and this process is reduced in transgenic mouse models of CF with the DeltaF508 mutation. However, this difference cannot be detected in an isolated preparation of brush-border membranes.

Prostate cancer management: (1) an update on localised disease

Prostate cancer is receiving ever more publicity with the result that more men are having their prostate specific antigen checked and a greater proportion of men are diagnosed with potentially curable localised disease. Advances in the therapeutic modalities including radical surgery, external beam radiotherapy, and brachytherapy have reduced the incidence of side effects and now offer patients a choice of treatments depending on their tumour characteristics, age, and co-morbidity. A significant proportion of men do not need intervention and may be safely kept under a "watch and wait" policy. The use of genetic markers may in the future distinguish between patients most likely to benefit from radical therapy and those in who either palliation or observation is more appropriate. This review examines the potentially curative options, as well as expectant management, outlining the pros and cons of each. The use of adjuvant and neoadjuvant therapy is also discussed.

Prostate cancer management: 2. An update on locally advanced and metastatic disease

Just under half of men with prostate cancer present with locally advanced or metastatic disease. A multidisciplinary approach is required to improve survival, minimise complications, and provide adequate palliation. Radiotherapy remains the mainstay of treatment for pelvic disease control and encouraging results have been reported with androgen ablation as adjuvant therapy. In metastatic disease androgen ablation is usually first line, although ultimately most tumours become hormone refractory, requiring second or third line treatments. Localised or systemic radiotherapy may be used for palliation in metastatic disease. With the advent of more potent bisphosphonates the common bony complications associated with metastases may be reduced. This, the second review of prostate cancer, explores the various treatments available to the multidisciplinary team.

Pubertal growth and development in cystic fibrosis: a retrospective review

AIM

Normal growth patterns are seen throughout the first decade in children with cystic fibrosis (CF). Growth in the second decade is, however, less satisfactory and may reflect pubertal delay. This study was performed to assess the extent of pubertal delay, to examine factors that influence the timing and magnitude of the pubertal growth spurt, and to establish whether the final height for most CF patients differed significantly from the normal population.

METHODS

Thirty subjects (16 male) attending a single centre were studied. Peak height velocity (PHV), final height and ages when achieved were compared with population norms. Outcome data were correlated with disease severity using Shwachman and Chrispin-Norman scores and forced expiratory volume in 1 s.

RESULTS

PHV was significantly later in both genders in this CF population compared with Tanner and Whitehouse standards: boys 14.6 y (95% confidence interval (95% CI) 12.4-16.8, p < 0.01) and girls 12.6 y (95% CI 10.5-14.7, p < 0.01). Mean PHV was also lower in both genders (boys 7.7 cm y(-1) and girls 6.4 cm y(-1), both p<0.001). However, final heights did not differ significantly from Freeman standards (height standard deviation scores: males--1.2, females--0.1); 52% of final heights equalled or exceeded the mid-parental centile.

CONCLUSION

CF patients showed suboptimal PHVs with a later pubertal growth spurt influenced by disease severity, but eventually achieved a normal final height.

Treatment of graft-versus-host disease after liver transplantation with basiliximab followed by bowel resection

Graft-versus-host disease (GVHD) after orthotopic liver transplantation (OLT) is a serious complication with mortality rates over 80%. Two patients with established GVHD after OLT were treated with Basiliximab, a chimeric murine human monoclonal antibody which binds to the alpha-chain of interleukin-2 receptor (IL-2R). Two males, aged 45 and 56 years, presented after OLT with a clinical picture consistent with GVHD. Quantitative measurements of recipient peripheral blood donor lymphocyte chimerism were carried out by flow cytometric analysis, and showed peak chimerism levels of 5% and 8%, respectively. Treatment comprised 3 doses of 1 g methyl prednisolone followed by 2 doses of 20 mg of Basiliximab. In both, treatment resulted in complete disappearance of macro-chimerism in blood. There was resolution of skin rash by day 7; however, diarrhea persisted. White cell scan showed increased uptake in the terminal ileum and small-bowel resection was performed in both patients. One patient is alive and well 36 months after OLT. The other patient had resolution of GVHD, but died of recurrent hepatitis C 1 year after OLT. The combination of immunological and surgical treatment for GVHD following solid organ transplantation has not previously been described.

Improving Appearance Model Matching Using Local Image Structure

We show how non-linear representations of local image structure can be used to improve the performance of model matching algorithms in medical image analysis tasks. Rather than represent the image structure using intensity values or gradients, we use measures that indicate the reliability of a set of local image feature detector outputs. These features are image edges, corners, and gradients. Feature detector outputs in flat, noisy regions tend to be ignored whereas those near strong structure are favoured. We demonstrate that combinations of these features give more accurate and reliable matching between models and new images than modelling image intensity alone. We also show that the approach is robust to non-linear changes in contrast, such as those found in multi-modal imaging.

The interleukin-1 receptor antagonist gene: a single-copy variant of the intron 2 variable number tandem repeat (VNTR) polymorphism

A variable number tandem repeat (VNTR) polymorphism exists within intron 2 of the human interleukin-1 receptor antagonist gene, consisting of perfect repeats of an 86-bp sequence. Five allelic variants have been identified wherein the number of repeats varies from two to six. This is the first report of a rare, single-copy allele designated IL1RN*0.

Effect of acute saline volume expansion in the anaesthetised DeltaF508 cystic fibrosis mouse

It has been suggested that CFTR Cl(-) channels in the renal inner medullary collecting duct may be involved in mediating increased renal salt excretion during extracellular fluid volume expansion. To investigate this hypothesis, in-vivo clearance experiments were performed comparing wild-type (WT) and DeltaF508-CFTR transgenic mice (cftr (tm2Cam)). Control animals were given a 0.1-ml bolus of 0.9% saline, followed by I.V. infusion at 0.3 ml x h(-1). Volume expansion was applied by infusing a 1-ml bolus of 0.9% saline followed by infusion at 0.6 ml x h(-1). No significant differences in renal NaCl handling between WT mice ( C(Na)=1.2 +/- 0.3 microl x min(-1), C(Cl)=4.0 +/- 0.5 microl x min(-1)) and DeltaF508-CFTR mice ( C(Na)=1.7 +/- 0.5 microl x min(-1), C(Cl)=4.1 +/- 0.8 microl x min(-1)) were observed under control conditions. Volume expansion resulted in large significant increases in NaCl clearance in both WT mice ( C(Na)=7.0 +/- 0.9 microl x min(-1), C(Cl)=12.0 +/- 0.6 microl x min(-1)) and DeltaF508-CFTR mice ( C(Na)=7.2 +/- 1.6 microl x min(-1), C(Cl)=11.0 +/- 2.2 microl x min(-1)). However, there was no significant difference between WT and DeltaF508-CFTR mice. In conclusion, renal NaCl excretion is not significantly different under basal conditions and during saline volume expansion in DeltaF508-CFTR mice. The data suggest that CFTR is not a physiologically important mediator of volume natriuresis.