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.