Molecular cartography uncovers evolutionary and microenvironmental dynamics in sporadic colorectal tumors

Colorectal cancer exhibits dynamic cellular and genetic heterogeneity during progression from precursor lesions toward malignancy. Analysis of spatial multi-omic data from 31 human colorectal specimens enabled phylogeographic mapping of tumor evolution that revealed individualized progression trajectories and accompanying microenvironmental and clonal alterations. Phylogeographic mapping ordered genetic events, classified tumors by their evolutionary dynamics, and placed clonal regions along global pseudotemporal progression trajectories encompassing the chromosomal instability (CIN+) and hypermutated (HM) pathways. Integrated single-cell and spatial transcriptomic data revealed recurring epithelial programs and infiltrating immune states along progression pseudotime. We discovered an immune exclusion signature (IEX), consisting of extracellular matrix regulators DDR1, TGFBI, PAK4, and DPEP1, that charts with CIN+ tumor progression, is associated with reduced cytotoxic cell infiltration, and shows prognostic value in independent cohorts. This spatial multi-omic atlas provides insights into colorectal tumor-microenvironment co-evolution, serving as a resource for stratification and targeted treatments.

Pre-frontal stimulation does not reliably increase reward responsiveness

Depression is the leading cause of disability worldwide and its effects can be fatal, with over 800,000 people dying by suicide each year. Neuromodulatory treatments such as transcranial magnetic stimulation (TMS) are being used to treat depression. Despite its endorsement by two regulatory bodies: NICE (2016) and the FDA (2008), there are major questions about the treatment efficacy and biological mechanisms of TMS. Ahn et al.'s (2013) justified the use of TMS in a clinical context in an important study indicating that excitatory TMS increases reward responsiveness. A pseudo-replication of this study by Duprat et al., (2016) also found a similar effect of active TMS, but only with the addition of an exploratory covariate to the analyses-trait reward responsiveness. Here we replicate Ahn et al.'s (2013) key study, and to test the reliability of the effects, and their dependency on trait reward responsiveness as described by Duprat et al., (2016). Using excitatory and sham TMS, we tested volunteers using the probabilistic learning task to measure their reward responsiveness both before and after stimulation. We also examined affect (positive, negative) following stimulation. Irrespective of TMS, the task was shown to be sensitive to reward responsiveness. However, we did not show TMS to be effective in increasing reward responsiveness and we did not replicate Ahn et al., (2013) or Duprat et al., (2016)'s key findings for TMS efficacy, where we provide evidence favouring the null. Moreover, exploratory analyses suggested following active stimulation, positive affect was reduced. Given our findings, we question the basic effects, which support the use of TMS for depression, particularly considering potential deleterious effects of reduced positive affect in patients with depression.

An examination of the effects of omni-channel service offerings on retailer performance

Purpose

Both online and brick and mortar retailers have invested heavily in developing omni-channel service offerings. Though seen as a competitive necessity, these omni-channel service offerings increase costs and complexities. The purpose of this study is to examine the effects of strategies involving bundles of omni-channel services related to order fulfillment and returns management on retailer performance.

Design/methodology/approach

Archival data were obtained for 152 retailers and analyzed using ordinary least squares regression. Robustness tests using an alternative dependent variable and a model-based classification strategy corroborate our findings.

Findings

Retailers offering full sets of high integration omni-channel services (buy online pick up in store, ship from store and in-store returns) have better performance (e.g. sales, growth and competitive position) and web sales than retailers that offer only a partial mix of these high integration services. Retailers offering a partial bundle of high integration services, in turn, have better performance and web sales than retailers that offer none of these services.

Originality/value

The research extends work that has examined the performance effects of omni-channel services on individual retailers. Our results indicate retailers benefit the most when offering a full set of high integration omni-channel services, suggesting retailers who have only adopted a subset of these services could improve performance through broader adoption of services. The results further indicate partial adoption of high integration services is better than no adoption.

Dual indexed library design enables compatibility of in-Drop single-cell RNA-sequencing with exAMP chemistry sequencing platforms

Background

The increasing demand of single-cell RNA-sequencing (scRNA-seq) experiments, such as the number of experiments and cells queried per experiment, necessitates higher sequencing depth coupled to high data quality. New high-throughput sequencers, such as the Illumina NovaSeq 6000, enables this demand to be filled in a cost-effective manner. However, current scRNA-seq library designs present compatibility challenges with newer sequencing technologies, such as index-hopping, and their ability to generate high quality data has yet to be systematically evaluated.

Results

Here, we engineered a dual-indexed library structure, called TruDrop, on top of the inDrop scRNA-seq platform to solve these compatibility challenges, such that TruDrop libraries and standard Illumina libraries can be sequenced alongside each other on the NovaSeq. On scRNA-seq libraries, we implemented a previously-documented countermeasure to the well-described problem of index-hopping, demonstrated significant improvements in base-calling accuracy on the NovaSeq, and provided an example of multiplexing twenty-four scRNA-seq libraries simultaneously. We showed favorable comparisons in transcriptional diversity of TruDrop compared with prior inDrop libraries.

Conclusions

Our approach enables cost-effective, high throughput generation of sequencing data with high quality, which should enable more routine use of scRNA-seq technologies.

Avian Papilloma and Squamous Cell Carcinoma: a Histopathological, Immunohistochemical and Virological study

In this retrospective study, we describe the histopathological findings in seven papillomas and 45 squamous cell carcinomas (SCCs) from psittacine birds, raptors and domestic fowl. The age of affected birds ranged from 3 to 40 years, with median age significantly higher in psittacines (P = 0.014). The majority of tumours were located in the skin (24/52, 46.2%) or uropygial gland (10/52, 19.2%). Thirty of the SCCs (66.7%) were well differentiated and 15 (33.3%) were poorly-differentiated. SCCs exhibited a significantly higher degree of nuclear pleomorphism (P = 0.005) and a greater proportion were ulcerated (P = 0.001) compared with papillomas; however, there was no significant difference in mitotic count (MC) or inflammation score. The expression of cyclo-oxygenase (COX)-2 and E-cadherin was investigated by immunohistochemistry. The COX-2 total score (TS) was significantly higher in SCCs compared with papillomas (P = 0.002), but the difference between COX-2 TS of well- and poorly-differentiated SCCs was not significant. COX-2 labelling was predominantly cytoplasmic, but some tumours had concurrent membranous and/or perinuclear labelling. SCCs with membranous labelling had a significantly higher MC (P = 0.028). A significantly higher proportion of SCCs were negative for E-cadherin compared with papillomas (P = 0.042), but there was no significant difference between well- and poorly-differentiated SCCs. Fourteen papillomas and SCCs from psittacines were also tested by polymerase chain reaction for the presence of Psittacus erithacus papillomavirus 1 and Psittacid herpesvirus 1, but all samples tested negative. We demonstrate for the first time the expression of COX-2 and E-cadherin in avian tissues, and suggest that these markers may be useful in differentiating papillomas from SCCs, particularly when sample size is small.

Detection of drug resistant Mycobacterium tuberculosis by high-throughput sequencing of DNA isolated from acid fast bacilli smears

BACKGROUND

Drug susceptibility testing for Mycobacterium tuberculosis (MTB) is difficult to perform in resource-limited settings where Acid Fast Bacilli (AFB) smears are commonly used for disease diagnosis and monitoring. We developed a simple method for extraction of MTB DNA from AFB smears for sequencing-based detection of mutations associated with resistance to all first and several second-line anti-tuberculosis drugs.

METHODS

We isolated MTB DNA by boiling smear content in a Chelex solution, followed by column purification. We sequenced PCR-amplified segments of the rpoB, katG, embB, gyrA, gyrB, rpsL, and rrs genes, the inhA, eis, and pncA promoters and the entire pncA gene.

RESULTS

We tested our assay on 1,208 clinically obtained AFB smears from Ghana (n = 379), Kenya (n = 517), Uganda (n = 262), and Zambia (n = 50). Coverage depth varied by target and slide smear grade, ranging from 300X to 12000X on average. Coverage of ≥20X was obtained for all targets in 870 (72%) slides overall. Mono-resistance (5.9%), multi-drug resistance (1.8%), and poly-resistance (2.4%) mutation profiles were detected in 10% of slides overall, and in over 32% of retreatment and follow-up cases.

CONCLUSION

This rapid AFB smear DNA-based method for determining drug resistance may be useful for the diagnosis and surveillance of drug-resistant tuberculosis.

CRISPR/Cas9-targeted removal of unwanted sequences from small-RNA sequencing libraries

In small RNA (smRNA) sequencing studies, highly abundant molecules such as adapter dimer products and tissue-specific microRNAs (miRNAs) inhibit accurate quantification of lowly expressed species. We previously developed a method to selectively deplete highly abundant miRNAs. However, this method does not deplete adapter dimer ligation products that, unless removed by gel-separation, comprise most of the library. Here, we have adapted and modified recently described methods for CRISPR/Cas9-based Depletion of Abundant Species by Hybridization ('DASH') to smRNA-seq, which we have termed miRNA and Adapter Dimer-DASH (MAD-DASH). In MAD-DASH, Cas9 is complexed with single guide RNAs (sgRNAs) targeting adapter dimer ligation products, alongside highly expressed tissue-specific smRNAs, for cleavage in vitro. This process dramatically reduces adapter dimer and targeted smRNA sequences, can be multiplexed, shows minimal off-target effects, improves the quantification of lowly expressed miRNAs from human plasma and tissue derived RNA, and obviates the need for gel-separation, greatly increasing sample throughput. Additionally, the method is fully customizable to other smRNA-seq preparation methods. Like depletion of ribosomal RNA for mRNA-seq and mitochondrial DNA for ATAC-seq, our method allows for greater proportional read-depth of non-targeted sequences.

An evaluation of methods for the isolation of nontuberculous mycobacteria from patients with cystic fibrosis, bronchiectasis and patients assessed for lung transplantation

BACKGROUND

RGM medium is an agar-based, selective culture medium designed for the isolation of nontuberculous mycobacteria (NTM) from the sputum of patients with cystic fibrosis (CF). We evaluated RGM medium for the detection of NTM in patients with CF (405 samples), bronchiectasis (323 samples) and other lung diseases necessitating lung transplantation (274 samples).

METHODS

In total, 1002 respiratory samples from 676 patients were included in the study. Direct culture on RGM medium, with incubation at two temperatures (30 °C and 37 °C), was compared with conventional culture of decontaminated samples for acid-fast bacilli (AFB) using both a solid medium (Löwenstein-Jensen medium) and a liquid medium (the Mycobacterial Growth Indicator Tube; MGIT).

RESULTS

For all three patient groups, significantly more isolates of NTM were recovered using RGM medium incubated at 30 °C than by any other method (sensitivity: 94.6% vs. 22.4% for conventional AFB culture; P < 0.0001). Significantly more isolates of Mycobacterium abscessus complex were isolated on RGM at 30 °C than by AFB culture (sensitivity: 96.1% vs. 58.8%; P < 0.0001). The recovery of Mycobacterium avium complex was also greater using RGM medium at 30 °C compared to AFB culture (sensitivity: 83% vs. 70.2%), although this difference was not statistically significant and a combination of methods was necessary for optimal recovery (P = 0.21).

CONCLUSIONS

In the largest study of RGM medium to date, we reaffirm its utility for isolation of NTM from patients with CF. Furthermore; we show that it also provides an effective tool for culture of respiratory samples from patients with bronchiectasis and other lung diseases.

Expanding the Spectrum of BAF-Related Disorders: De Novo Variants in SMARCC2 Cause a Syndrome with Intellectual Disability and Developmental Delay

SMARCC2 (BAF170) is one of the invariable core subunits of the ATP-dependent chromatin remodeling BAF (BRG1-associated factor) complex and plays a crucial role in embryogenesis and corticogenesis. Pathogenic variants in genes encoding other components of the BAF complex have been associated with intellectual disability syndromes. Despite its significant biological role, variants in SMARCC2 have not been directly associated with human disease previously. Using whole-exome sequencing and a web-based gene-matching program, we identified 15 individuals with variable degrees of neurodevelopmental delay and growth retardation harboring one of 13 heterozygous variants in SMARCC2, most of them novel and proven de novo. The clinical presentation overlaps with intellectual disability syndromes associated with other BAF subunits, such as Coffin-Siris and Nicolaides-Baraitser syndromes and includes prominent speech impairment, hypotonia, feeding difficulties, behavioral abnormalities, and dysmorphic features such as hypertrichosis, thick eyebrows, thin upper lip vermilion, and upturned nose. Nine out of the fifteen individuals harbor variants in the highly conserved SMARCC2 DNA-interacting domains (SANT and SWIRM) and present with a more severe phenotype. Two of these individuals present cardiac abnormalities. Transcriptomic analysis of fibroblasts from affected individuals highlights a group of differentially expressed genes with possible roles in regulation of neuronal development and function, namely H19, SCRG1, RELN, and CACNB4. Our findings suggest a novel SMARCC2-related syndrome that overlaps with neurodevelopmental disorders associated with variants in BAF-complex subunits.

Microscopic polyangiitis secondary to Mycobacterium abscessus in a patient with bronchiectasis: a case report

Background

Non-Tuberculous Mycobacterial–pulmonary disease (NTM-PD) is increasing in incidence and prevalence. Mycobacterium abscessus (M.abscessus) is a rapid growing multi-resistant NTM associated with severe NTM-PD requiring prolonged antibiotic therapy. Complications of therapy are common but reports on direct complications of active NTM-PD are rare. Vasculitis has been described as a rare complication of NTM-PD, most often in individuals with inherited immune defects. This case is the first to describe an ANCA positive vasculitide (Microscopic Polyangiitis) secondary to M.abscessus pulmonary disease.

Case presentation

A 70 year old female with bronchiectasis underwent a clinical decline associated with the growth of M.abscessus and was diagnosed with NTM-PD. Before treatment could be initiated she developed small joint arthralgia and a glove and stocking axonal loss sensorimotor neuropathy. Positive Perinuclear Anti-Neutrophil Cytoplasmic Antibodies (P-ANCA) and Myeloperoxidase-ANCA (MPO-ANCA) titres led to a diagnosis of microscopic polyangiitis. Further investigation revealed reduced interferon-gamma production but no other significant immune dysfunction.

Dual treatment with immunosuppressive therapy (Corticosteroids/Cyclophosphamide) for vasculitis and antimicrobial therapy for M.abscessus NTM-PD was initiated. Clinical stability was difficult to achieve with reductions in immunosuppression triggering vasculitic flares. One flare led to retinal vein occlusion with impending visual loss requiring escalation in immunosuppression to Rituximab infusions. An increase in immunosuppression led to a deterioration in NTM-PD necessitating alterations to antibiotic regimes. Adverse effects including alopecia and Achilles tendonitis have further limited antibiotic choices resulting in a strategy of pulsed intra-venous therapy to stabilise NTM-PD.

Conclusions

This is the first reported case of an ANCA positive vasculitis secondary to M.abscessus pulmonary disease. This rare but important complication had a significant impact on the patient adding to the complexity of an already significant disease and treatment burden. The potential role of reduced interferon-gamma production in this case highlights the importance of investigating immune function in those with mycobacterial infection and the intricate relationship between mycobacterial infection and immune dysfunction. Immune dysfunction caused by genetic defects or immunosuppressive therapy is a known risk factor for NTM-PD. Balancing immunosuppressive therapy with prolonged antimicrobial treatment is challenging and likely to become more common as the number of individuals being treated with biologics and immunosuppressive agents increases.

Discovery and Validation of Circulating Biomarkers of Colorectal Adenoma by High-Depth Small RNA Sequencing

Purpose: Colorectal cancer is the third most common cancer worldwide, causing approximately 700,000 deaths each year. The majority of colorectal cancers begin as adenomas. Definitive screening for colorectal adenomas is currently accomplished through colonoscopy but, owing largely to costs and invasiveness, is typically limited to patient groups at higher risk by virtue of age or family history. We sought to determine if blood-based small RNA markers could detect colorectal adenoma.Experimental Design: We applied high-depth small RNA sequencing to plasma from a large (n = 189) cohort of patients, balanced for age, sex, and ancestry. Our analytical methodology allowed for the detection of both microRNAs and other small RNA species. We replicated sequencing results by qPCR on plasma samples from an independent cohort (n = 140).Results: We found several small RNA species with significant associations to colorectal adenoma, including both microRNAs and non-microRNA small RNAs. These associations were robust to correction for patient covariates, including age. Among the adenoma-associated small RNAs, two, a miR-335-5p isoform and an un-annotated small RNA, were validated by qPCR in an independent cohort. A classifier trained on measures of these two RNAs in the discovery cohort yields an AUC of 0.755 (0.775 with age) for adenoma detection in the independent cohort. This classifier accurately detects adenomas in patients under 50 and is robust to sex or ancestry.Conclusions: Circulating small RNAs (including but not limited to miRNAs) discovered by sequencing and validated by qPCR identify patients with colorectal adenomas effectively. Clin Cancer Res; 24(9); 2092-9. ©2018 AACR.

Genomic regulation of invasion by STAT3 in triple negative breast cancer

Breast cancer is a heterogeneous disease comprised of four molecular subtypes defined by whether the tumor-originating cells are luminal or basal epithelial cells. Breast cancers arising from the luminal mammary duct often express estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth receptor 2 (HER2). Tumors expressing ER and/or PR are treated with anti-hormonal therapies, while tumors overexpressing HER2 are targeted with monoclonal antibodies. Immunohistochemical detection of ER, PR, and HER2 receptors/proteins is a critical step in breast cancer diagnosis and guided treatment. Breast tumors that do not express these proteins are known as "triple negative breast cancer" (TNBC) and are typically basal-like. TNBCs are the most aggressive subtype, with the highest mortality rates and no targeted therapy, so there is a pressing need to identify important TNBC tumor regulators. The signal transducer and activator of transcription 3 (STAT3) transcription factor has been previously implicated as a constitutively active oncogene in TNBC. However, its direct regulatory gene targets and tumorigenic properties have not been well characterized. By integrating RNA-seq and ChIP-seq data from 2 TNBC tumors and 5 cell lines, we discovered novel gene signatures directly regulated by STAT3 that were enriched for processes involving inflammation, immunity, and invasion in TNBC. Functional analysis revealed that STAT3 has a key role regulating invasion and metastasis, a characteristic often associated with TNBC. Our findings suggest therapies targeting STAT3 may be important for preventing TNBC metastasis.

A Syndromic Neurodevelopmental Disorder Caused by De Novo Variants in EBF3

Early B cell factor 3 (EBF3) is a member of the highly evolutionarily conserved Collier/Olf/EBF (COE) family of transcription factors. Prior studies on invertebrate and vertebrate animals have shown that EBF3 homologs are essential for survival and that loss-of-function mutations are associated with a range of nervous system developmental defects, including perturbation of neuronal development and migration. Interestingly, aristaless-related homeobox (ARX), a homeobox-containing transcription factor critical for the regulation of nervous system development, transcriptionally represses EBF3 expression. However, human neurodevelopmental disorders related to EBF3 have not been reported. Here, we describe three individuals who are affected by global developmental delay, intellectual disability, and expressive speech disorder and carry de novo variants in EBF3. Associated features seen in these individuals include congenital hypotonia, structural CNS malformations, ataxia, and genitourinary abnormalities. The de novo variants affect a single conserved residue in a zinc finger motif crucial for DNA binding and are deleterious in a fly model. Our findings indicate that mutations in EBF3 cause a genetic neurodevelopmental syndrome and suggest that loss of EBF3 function might mediate a subset of neurologic phenotypes shared by ARX-related disorders, including intellectual disability, abnormal genitalia, and structural CNS malformations.

De Novo Truncating Variants in ASXL2 Are Associated with a Unique and Recognizable Clinical Phenotype

The ASXL genes (ASXL1, ASXL2, and ASXL3) participate in body patterning during embryogenesis and encode proteins involved in epigenetic regulation and assembly of transcription factors to specific genomic loci. Germline de novo truncating variants in ASXL1 and ASXL3 have been respectively implicated in causing Bohring-Opitz and Bainbridge-Ropers syndromes, which result in overlapping features of severe intellectual disability and dysmorphic features. ASXL2 has not yet been associated with a human Mendelian disorder. In this study, we performed whole-exome sequencing in six unrelated probands with developmental delay, macrocephaly, and dysmorphic features. All six had de novo truncating variants in ASXL2. A careful review enabled the recognition of a specific phenotype consisting of macrocephaly, prominent eyes, arched eyebrows, hypertelorism, a glabellar nevus flammeus, neonatal feeding difficulties, hypotonia, and developmental disabilities. Although overlapping features with Bohring-Opitz and Bainbridge-Ropers syndromes exist, features that distinguish the ASXL2-associated condition from ASXL1- and ASXL3-related disorders are macrocephaly, absence of growth retardation, and more variability in the degree of intellectual disabilities. We were also able to demonstrate with mRNA studies that these variants are likely to exert a dominant-negative effect, given that both alleles are expressed in blood and the mutated ASXL2 transcripts escape nonsense-mediated decay. In conclusion, de novo truncating variants in ASXL2 underlie a neurodevelopmental syndrome with a clinically recognizable phenotype. This report expands the germline disorders that are linked to the ASXL genes.

Should all patients with unexplained anaemia be screened for chronic lead poisoning?

The global prevalence of lead poisoning is declining. However, the prevalence of lead poisoning in patients with either microcytic or normocytic anaemia is unknown. Blood samples from anaemic patients residing in south-east London without an obvious cause for anaemia had their blood lead concentration (BLC) analysed.A batch of 988 samples was analysed for BLC using atomic absorption spectroscopy. Median haemoglobin was 10.3 g/dL (range: 4.2–10.9) in females, 10.6 g/dL (range: 5.2–11.4) in males and 10.7 g/dL (range: 6.7–10.9) in children. Median BLC was 2.63 μg/dL (0.21–24.0 μg/dL; 95th centile 7.54 μg/dL). Fifteen samples (1.5%) had a BLC>10.0 μg/dL, five samples (1%)>15.0 μg/dL and one sample (0.1%)>20.0 μg/L. In the 106 children, median BLC was 2.34 μg/dL (0.5–14.5 μg/dL; 95th centile 6.12 μg/ dL). Only one child (14.5 μg/L) had a BLC>10.0 μg/dL. There was a poor correlation between haemoglobin and BLC (r2=0.08).Routine screening for lead poisoning cannot be justified in all patients with unexplained anaemia, unless there is a history or clinical features to suggest lead toxicity. Additionally, we have shown that in this former high-risk area for lead exposure, there is a low point prevalence of significant lead poisoning, even in an anaemic population.

A 502-Base Free-Solution Electrophoretic DNA Sequencing Method Using End-Attached Wormlike Micelles

We demonstrate that the use of wormlike nonionic micelles as drag-tags in end-labeled free-solution electrophoresis ("micelle-ELFSE") provides single-base resolution of Sanger sequencing products up to 502 bases in length, a nearly 2-fold improvement over reported ELFSE separations. "CiEj" running buffers containing 48 mM C12E5, 6 mM C10E5, and 3 M urea (32.5 °C) form wormlike micelles that provide a drag equivalent to an uncharged DNA fragment with a length (α) of 509 bases (effective Rh = 27 nm). Runtime in a 40 cm capillary (30 kV) was 35 min for elution of all products down to the 26-base primer. We also show that smaller Triton X-100 micelles give a read length of 103 bases in a 4 min run, so that a combined analysis of the Sanger products using the two buffers in separate capillaries could be completed in 14 min for the full range of lengths. A van Deemter analysis shows that resolution is limited by diffusion-based peak broadening and wall adsorption. Effects of drag-tag polydispersity are not observed, despite the inherent polydispersity of the wormlike micelles. We ascribe this to a stochastic size-sampling process that occurs as micelle size fluctuates rapidly during the runtime. A theoretical model of the process suggests that fluctuations occur with a time scale less than 10 ms, consistent with the monomer exchange process in nonionic micelles. The CiEj buffer has a low viscosity (2.7 cP) and appears to be semidilute in micelle concentration. The large drag-tag size of the CiEj buffers leads to steric segregation of the DNA and tag for short fragments and attendant mobility shifts.

Clostridium perfringens type-D enterotoxaemia in cattle: the diagnostic significance of intestinal epsilon toxin

The aims of this study were to describe 42 cases of Clostridium perfringens type-D enterotoxaemia in cattle seen between 2003 and 2014 and to determine the diagnostic value of detecting epsilon toxin in bovine intestinal content. All cases in the series had histological brain changes considered pathognomonic for C. perfringens type-D enterotoxaemia in sheep and goats and the epsilon toxin of C. perfringens was concurrently detected in the intestinal contents of 15 (36 per cent) cases. The data from the case series indicate that intestinal epsilon toxin has a sensitivity of 56 per cent compared with histology of the brain for diagnosis of bovine C. perfringens type-D enterotoxaemia. The diagnostic specificity of detecting epsilon toxin in bovine intestinal content was investigated by screening intestinal contents of 60 bovine carcases submitted for postmortem examination. Epsilon toxin was detected in 11 (18 per cent) carcases but no pathognomonic histological brain change was found in any. The specificity of intestinal epsilon toxin was estimated to be 80.4 per cent. These studies demonstrate that for a definitive diagnosis of C. perfringens type-D enterotoxaemia in cattle histological examination of the brain is essential as the presence of epsilon toxin in the intestinal contents alone is neither sensitive nor specific enough.

Geospatial Resolution of Human and Bacterial Diversity with City-Scale Metagenomics

The panoply of microorganisms and other species present in our environment influence human health and disease, especially in cities, but have not been profiled with metagenomics at a city-wide scale. We sequenced DNA from surfaces across the entire New York City (NYC) subway system, the Gowanus Canal, and public parks. Nearly half of the DNA (48%) does not match any known organism; identified organisms spanned 1,688 bacterial, viral, archaeal, and eukaryotic taxa, which were enriched for harmless genera associated with skin (e.g., Acinetobacter). Predicted ancestry of human DNA left on subway surfaces can recapitulate U.S. Census demographic data, and bacterial signatures can reveal a station’s history, such as marine-associated bacteria in a hurricane-flooded station. Some evidence of pathogens was found (Bacillus anthracis), but a lack of reported cases in NYC suggests that the pathogens represent a normal, urban microbiome. This baseline metagenomic map of NYC could help long-term disease surveillance, bioterrorism threat mitigation, and health management in the built environment of cities.

Exome sequencing in amyotrophic lateral sclerosis identifies risk genes and pathways

Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment. We report the results of a moderate-scale sequencing study aimed at increasing the number of genes known to contribute to predisposition for ALS. We performed whole-exome sequencing of 2869 ALS patients and 6405 controls. Several known ALS genes were found to be associated, and TBK1 (the gene encoding TANK-binding kinase 1) was identified as an ALS gene. TBK1 is known to bind to and phosphorylate a number of proteins involved in innate immunity and autophagy, including optineurin (OPTN) and p62 (SQSTM1/sequestosome), both of which have also been implicated in ALS. These observations reveal a key role of the autophagic pathway in ALS and suggest specific targets for therapeutic intervention.

Serotonin toxicity from antidepressant overdose and its association with the T102C polymorphism of the 5-HT2A receptor

Serotonin toxicity results from serotonin excess in the central nervous system from serotonergic drugs. Previous studies suggest an association between T102C polymorphism of the serotonin 2A (5-hydroxytryptamine 2A) receptor gene and serotonergic adverse effects with serotonergic drugs. We aimed to determine whether there is an association between the T102C polymorphism and serotonin toxicity in patients taking serotonergic drug overdoses. Ninety-five patients presenting with serotonergic drug overdoses were examined for serotonin toxicity and had blood collected for DNA analysis. A diagnosis of serotonin toxicity was made in 14 patients (15%) based on the Hunter Serotonin Toxicology Criteria. Four of the 14 patients (29%) with serotonin toxicity had the C/C genotype compared with 20/81 (25%) without serotonin toxicity. There were no differences in age or sex, but the median defined daily dose taken by patients with serotonin toxicity was 27 (14-84) compared with 18 (2-136) in patients without serotonin toxicity (P=0.06). There was no association between serotonin toxicity and the T102C polymorphism in patients taking a serotonergic drug overdose.

UK guidance document: treatment of metastatic breast cancer

Although there have been major improvements in the management of breast cancer, with a rapidly falling death rate despite an increasing incidence of the disease, metastatic breast cancer remains common and the cause of death in nearly 12 000 women annually in the UK. Numerous treatment options are available that either target the tumour or reduce the complications of the disease. Clinical decision making depends on knowledge of the extent and biology of the disease and available drug options, an understanding of the functional status, and also the wishes and expectations of the individual patient. In addition, the organisation of services and support of the patient are essential components of high-quality care. The National Institute for Health and Clinical Excellence (NICE) has produced guidelines for the treatment of advanced breast cancer, which in some areas have perhaps failed to appreciate the complexity of patient management. This guidance document aims to provide succinct practical advice on the treatment of metastatic breast cancer, highlight some limitations of the NICE guidelines, and provide suggestions for management where available data are limited.

Delay times between harvesting or collection of food products and consumption for use in radiological assessments

From a radiological protection point of view, the inclusion of delay times when carrying out assessments of dose from consumption of foods should be considered. A review of delay times has been carried out to update a report published in 1983, to take account of changes and modernisations in industrial food processes, together with changes in diet and popularity of different foods in the United Kingdom. The new review considered more foods and data for existing foods have been reconsidered to check whether manufacturing processes or procedures have changed the shelf-life of any products. For some foods there have been changes made to the recommended delay times because of changes in manufacture or handling of the fresh foodstuff. A discussion is also included on the appropriate use of delay times in dose assessments.

Management of cardiac health in trastuzumab-treated patients with breast cancer: updated United Kingdom National Cancer Research Institute recommendations for monitoring

More women are living with and surviving breast cancer, because of improvements in breast cancer care. Trastuzumab (Herceptin®▾) has significantly improved outcomes for women with HER2-positive tumours. Concerns about the cardiac effects of trastuzumab (which fundamentally differ from the permanent myocyte loss associated with anthracyclines) led to the development of cardiac guidelines for adjuvant trials, which are used to monitor patient safety in clinical practice. Clinical experience has shown that the trial protocols are not truly applicable to the breast cancer population as a whole, and exclude some women from receiving trastuzumab, even though they might benefit from treatment without long-term adverse cardiac sequelae. Consequently, five oncologists who recruited patients to trastuzumab trials, some cardiologists with whom they work, and a cardiovascular lead general practitioner reviewed the current cardiac guidelines in the light of recent safety data and their experience with adjuvant trastuzumab. The group devised recommendations that promote proactive pharmacological management of cardiac function in trastuzumab-treated patients, and that apply to all patients who are likely to receive standard cytotoxic chemotherapy. Key recommendations include: a monitoring schedule that assesses baseline and on-treatment cardiac function and potentially reduces the overall number of assessments required; intervention strategies with cardiovascular medication to improve cardiac status before, during, and after treatment; simplified rules for starting, interrupting and discontinuing trastuzumab; and a multidisciplinary approach to breast cancer care.

Doctors' knowledge of the appropriate use and route of administration of antidotes in the management of recreational drug toxicity

BACKGROUND

Specific antidotes (eg, naloxone, flumazenil, cyproheptadine and benzodiazepines) are available for the management of certain recreational drug-induced toxicities. Some controversies surround the use of some of these antidotes, especially flumazenil in benzodiazepine toxicity. There are no previously published data on doctors' knowledge of the use of these specific antidotes.

METHODS

A questionnaire survey was designed to determine internal/emergency medicine doctors' knowledge of the appropriate use of antidotes in the management of clinical scenarios of acutely poisoned patients. For nine simulated clinical scenarios of acute toxicity from recreational drugs (benzodiazepines, cocaine, N-methyl-L-(3,4-methylene-dioxyphenyl)-2-aminopropane (MDMA)-induced serotonin toxicity and opioids), they were asked to indicate whether the suggested antidote and route of administration were correct.

RESULTS

42 physicians of all grades completed the questionnaire. The mean correct score was 5.4 (SD 1.1) (median 6, interquartile range 5-7). The percentages correct for the various clinical scenarios were 68.3% for opioid toxicity, 81% for benzodiazepine toxicity, 28.6% for MDMA-induced serotonin toxicity and 70.2% for cocaine toxicity. Doctors were more likely to record an answer of "unsure" for the use of cyproheptadine in ST serotonin toxicity (28.6%) compared with the use of the other antidotes (1.4%; p<0.001).

CONCLUSION

Knowledge of the appropriate use of antidotes in recreational drug toxicity is not consistent, with poorer knowledge on the use of newer antidotes such as cyproheptadine in serotonin toxicity. Education is required both to increase overall knowledge on the use of specific antidotes in the management of recreational drug-induced toxicity, as well as focusing on newer antidotes such as cyproheptadine.

Improvement in the management of acutely poisoned patients using an electronic database, prospective audit and targeted educational intervention

PROBLEM

The need to improve the clinical assessment and management of acutely poisoned patients presenting to an NHS hospital emergency department (ED).

DESIGN

Creation of an electronic clinical toxicology database to prospectively collect all aspects of clinical information on poisoned-patient presentations. Systematic analysis of collated information to identify shortfalls in patient assessment and management. Bimonthly audit meetings, and design and implementation of educational interventions to address identified shortfalls. Ongoing audit to demonstrate continued improvement in patient care.

BACKGROUND AND SETTING

ED in tertiary-level inner-city London teaching hospital. Study conducted by staff from the ED and clinical toxicology service.

KEY MEASURES FOR IMPROVEMENT

Demonstration of overall reduction in the incidence of predefined shortfalls in patient assessment and management during 12-month study period.

STRATEGIES FOR IMPROVEMENT

Targeted educational lectures and case-based clinical scenarios addressing identified deficiencies in the knowledge required to effectively manage poisoned patients. Weekly case-based anonymised feedback report sent electronically to staff involved in caring for poisoned patients.

EFFECTS OF CHANGE

Implementation of targeted teaching of ED staff and regular electronic distribution of teaching cases. Between the first and second 6 months of the study, there was a significant increase in the proportion of presentations for which clinical management was graded as "good" (77.6% to 89.4%, p<0.0001) and a significant reduction in the proportion of "major" (9.9% to 5.8%, p = 0.012) and "minor" (12.6% to 4.8%, p<0.0001) shortfalls.

LESSONS LEARNT

Systematic collection of clinical information, using a dedicated electronic database and subsequent review and audit of collated data by interested clinicians, enabled design and implementation of targeted educational interventions to address shortfalls in patient management. This process has led to significant improvements in the clinical care of acutely poisoned patients presenting to the ED.

Can medical students identify recreational drugs by name?

BACKGROUND

Recreational drug toxicity is a common reason for presentation to the Emergency Department. Knowledge of recreational drug names is important to allow targeted assessment of patients presenting with recreational drug toxicity.

AIMS

To assess final year medical student knowledge of proper and street names for recreational drugs.

DESIGN

Questionnaire survey of final year medical students attending a revision lecture.

METHODS

There were two questionnaires used in this study. The first contained either proper names of recreational drugs or names sounding similar to recreational drugs or licensed pharmaceutical products; students were asked to identify which of these were recreational drugs. The second contained street names of recreational drugs and the students were asked to identify which recreational drug the street name referred to.

RESULTS

One hundred and thirty-five students completed the questionnaire 1. The mean total score (+/-SD) of correct answers was 7.15 +/- 2.26 (range 2-13) out of a maximum of 15. One hundred and fifteen students completed questionnaire 2. The mean total score (+/-SD) of correctly identified street names was 11.0 +/- 2.6 (range 0-17) out of a maximum of 24. No individual student was able to correctly identify all the street names for the recreational drugs listed in the survey.

CONCLUSION

We have shown that final year medical students have variable knowledge of both the proper and street names of recreational drugs. There is a need for improved education of medical students in the names of recreational drugs and the sources of information available to assist them in identifying what drugs an individual has taken.

Severe hypokalaemic metabolic alkalosis following ingestion of gaviscon®

INTRODUCTION

Uncommon metabolic abnormalities in the emergency department could be a result of drug overdose due to uncommon agents.

CASE REPORT

A 35-year-old male presented to the emergency department with a Glasgow Coma Scale (GCS) of 3/15 and a normal pulse rate and blood pressure. Subsequent questioning after recovery revealed he had ingested 2 L of Gaviscon over the preceding 48 hours. He had normal haematology, liver, and renal function during admission. The electrocardiogram showed T wave inversion in the inferior leads on admission. Arterial blood gas on air was: pH 7.54, HCO3 50 mmol/L (50 meq/L), Chloride 66 mmol/L, anion gap was 19, pO2 11 kPa (82.5 mmHg), and pCO2 8 kPa (60 mmHg). Serum sodium was 127 mmol/L and serum potassium was 1.6 mmol/L. His GCS improved within one hour of admission with supportive care, and his serum potassium and bicarbonate improved within 24 hours. He subsequently made a full recovery. Discussion. Bicarbonate ingestion in the form of Gaviscon(R) and vomiting made this patient alkalotic, and simple supportive care provided effective management with a complete recovery.

CONCLUSION

This case illustrates how a severe metabolic alkalosis can result from a significant ingestion of Gaviscon, and that such presentations can give rise to diagnostic dilemma.

Review of trends in the UK population dose

The Radiation Protection Division of the Health Protection Agency (HPA-RPD), formerly the National Radiological Protection Board, has periodically reported the doses to members of the public and workers in the UK from all sources of radiation. This paper is a review of the doses reported in these publications from the 1970s to 2000 or later. The paper aims to present how the estimated doses received by the UK population have changed over this time period, and where possible from earlier years as well, from all sources of radiation. It was not possible to directly compare the doses reported in the earlier reports. There have been changes in the type of doses estimated, the dosimetry (in particular the definition of effective dose) and improvements made in the measurement of natural background doses. In these cases the earlier reported doses have been recalculated using modern dosimetry so that the doses can be compared. The occupational doses reported in this paper are for those workers involved in the civil nuclear power production industry, industrial radiography or from the medical use of radiation sources. For workers it was found that the individual and collective dose has decreased significantly over this time through the introduction of legislation, the improvement in technology and better working practices. Members of the public are exposed to radiation following the atmospheric testing of nuclear weapons, discharges from UK civil nuclear sites and from diagnostic radiology as well as from natural sources. Exposure to anthropogenic sources has decreased over the period considered in this paper. However, the dose to the UK population as a whole, presented as a per caput dose to a population of 55 million, has not changed significantly as it is dominated by the constant level of exposure to natural sources of radiation.

Nutrition, synchronization, and management of beef embryo transfer recipients

A commercially viable cattle embryo transfer industry was established during the early 1970s. Initially, techniques for transferring cattle embryos were exclusively surgical. However, by the early 1980s, most embryos were transferred nonsurgically. For an embryo transfer program to be effective, numerous factors need to be in place to ensure success. Nutrition, estrous cycle control, and recipient management are all responsible for the success or failure in fertility for a given herd. Utilization of body condition scores is a practical method to determine nutritional status of the recipient herd. Prepartum nutrition is critical to ensure that cows calve in adequate body condition to reinitiate postpartum estrous cycles early enough to respond to synchronization protocols. Estrus synchronization for embryo transfer after detected estrus or for fixed-time embryo transfer without estrus detection are effective methods to increase the number of calves produced by embryo transfer. In addition, resynchronization of nonpregnant recipients effectively ensures that a high percentage of recipients will return to estrus during a 72 h interval and are eligible for subsequent embryo transfers. Numerous additional factors need to be assessed to ensure that the recipient herd achieves its reproductive potential. These factors include assessing the merits of nulliparous, primiparous, or multiparous cows, ensuring that facilities allow for minimal stress, and that the herd health program is well-defined and followed. Numerous short- and long-term factors contribute to recipients conceiving to a transferred embryo, maintaining the embryo/fetus to term, delivering the calf without assistance and raising and weaning a healthy calf.

Paracetamol availability and recent changes in paracetamol poisoning: is the 1998 legislation limiting availability of paracetamol being followed?

OBJECTIVE

To determine the degree of adherence to legislation introduced in 1998 restricting the availability of over the counter paracetamol.

DESIGN

A prospective observational study.

SETTING

An emergency department in an inner city London teaching hospital. Pharmacy and non-pharmacy outlets in south London.

MAIN OUTCOME MEASURES

(1) The source of paracetamol ingested by 107 patients presenting with an acute paracetamol overdose (2001-2003) and (2) the ability to purchase paracetamol from pharmacy and non-pharmacy outlets in a manner contravening paracetamol pack size legislation (2004).

RESULTS

Potentially toxic amounts of paracetamol in excess of pack size restrictions were purchased in 70% (17 of 24) of outlets. Forty six per cent of patients who had ingested a potentially toxic dose of paracetamol obtained the tablets in a manner contravening the 1998 legislation.

CONCLUSION

Legislation limiting the availability of over the counter paracetamol is not being adhered to in south London. A significant number of patients ingesting a potentially toxic dose of paracetamol report purchasing the tablets in a manner contravening the legislation. Studies that attempt to assess the impact of the legislation need to be interpreted in the context of these results. Measures to enforce current legislation may help to reduce the severity of paracetamol poisoning in the UK.

Variations in radiation exposures of adults and children in the UK

Members of the UK population receive radiation doses from a number of sources including cosmic radiation, from uranium, thorium and their decay products, particularly radon, and from medical sources. On average, members of the UK population receive an effective dose of about 200 mSv over their lifetime. This results in a risk of fatal cancer of about 1%. However, the radiation dose is not the same to all individuals. Some components give doses that vary systematically from one region to another. Doses may also vary greatly from one individual to another. The rate at which the dose is accumulated may vary as the individual ages. Different organs and tissues do not necessarily receive the same dose. This paper discusses these factors and attempts to quantify them. Cosmic rays deliver doses which vary little across the body or between individuals. Terrestrial gamma rays also deliver more or less uniform whole-body doses, but the difference between individuals can be greater. Radionuclides in food deliver doses which vary both across the body and between individuals. These variations are even more marked in the case of doses from radon and from medical exposures.

Review of the radiation exposure of the UK population

Since 1974 the National Radiological Protection Board (now the Radiation Protection Division of the Health Protection Agency) has produced reviews of the levels of exposure to ionising radiation in the UK, from sources of natural and artificial origin. The latest review (Watson et al 2005 Ionising Radiation Exposure of the UK Population: 2005 Review HPA-RPD-001 (Chilton: HPA-RPD)) in the series gives estimates of annual doses based predominantly on data collected for the years 2001-2003. The overall average annual dose is rounded to 2.7 mSv, and the average annual dose from natural radiation is found to be 2.2 mSv. The overall average annual dose is slightly increased over that found in the previous, 1999, review. This increase is mainly due to a larger contribution from medical irradiation.

Metaraminol (Aramine) in the management of a significant amlodipine overdose

OBJECTIVE

To report a patient with a significant amlodipine self-poisoning who failed to clinically respond to conventional treatment and was managed with metaraminol (Aramine).

PATIENT

A 43-year old male presenting after ingestion of 560 mg amlodipine, who failed to respond clinically to treatment with fluid resuscitation, calcium salts, glucagon and norepinephrine/epinephrine inotropic support.

MAIN RESULTS

Following a loading bolus of 2 mg and intravenous infusion (83 microg/min) of metaraminol (Aramine) there was improvement in his blood pressure, cardiac output and urine output.

CONCLUSIONS

This is the first case report of the beneficial use of metaraminol (aramine) in the management of significant amlodipine poisoning unresponsive to conventional therapy.

Dietzia strain X: a newly described Actinomycete isolated from confluent and reticulated papillomatosis

Confluent and reticulated papillomatosis (CRP) is a rare skin disorder. To date its aetiology remains uncertain. The possibility of an infectious aetiology has been supported by case reports of therapeutic response to antibiotic therapy. We have isolated and identified a previously unknown Dietzia strain, an Actinomycete, from skin scrapings of a 17-year-old boy with CRP. We propose that this organism may be the aetiological agent of CRP. Further investigations are necessary to determine the potential role of this Actinomycete in the pathogenesis of CRP.

Naloxone in opioid poisoning: walking the tightrope

Acute opioid intoxication and overdose are common causes of presentation to emergency departments. Although naloxone, a pure opioid antagonist, has been available for many years, there is still confusion over the appropriate dose and route of administration. This article looks at the reasons for this uncertainty and undertakes a literature review from which a treatment algorithm is presented.

Measuring plasma salicylate concentrations in all patients with drug overdose or altered consciousness: is it necessary?

BACKGROUND

Salicylate self poisoning is potentially fatal. Plasma salicylate concentrations can be used to guide management when taken in the context of clinical features of toxicity and acid base status. Previous studies in the USA and Hong Kong have shown that routine measurement of plasma salicylate concentrations in all overdose patients is inappropriate, but there have been no previous studies in the UK.

METHODS

A retrospective case note study from 1 February 2001 to 31 January 2002 was undertaken at the emergency department of St. Thomas' Hospital, London. Records were reviewed and information on demographic data, history, details of salicylate overdose, and documentation of clinical features of salicylate toxicity recorded.

RESULTS

In total, 722 patient episodes were identified, of which 596 case notes were available and appropriate for inclusion in this study. Plasma salicylate concentrations (range 15-428 mg/l) were detectable in 50 patients (three notes not available), of whom 38 had given a positive history. The history of salicylate poisoning had a sensitivity of 81% (95% confidence interval (CI) 67 to 91%) and the predictive value of a negative history of salicylate ingestion in not detecting salicylate concentrations was 98% (95% CI 97 to 99%). Insufficient information on clinical features of salicylate toxicity was recorded in 569 patients (including 35 patients who had a history of salicylate ingestion).

CONCLUSION

History of salicylate ingestion has a high sensitivity and negative predictive value with respect to the detection of plasma salicylate concentrations. However, current practice indicates that insufficient information is obtained from patients about the clinical features of toxicity. Routine measurement of plasma salicylate concentrations is not required unless there is (a) a positive history of ingestion of salicylates or (b) a reduced level of consciousness or other reason limiting the validity of the history obtained, together with clinical features consistent with salicylate poisoning.

Acute poisoning: understanding 90% of cases in a nutshell

The acutely poisoned patient remains a common problem facing doctors working in acute medicine in the United Kingdom and worldwide. This review examines the initial management of the acutely poisoned patient. Aspects of general management are reviewed including immediate interventions, investigations, gastrointestinal decontamination techniques, use of antidotes, methods to increase poison elimination, and psychological assessment. More common and serious poisonings caused by paracetamol, salicylates, opioids, tricyclic antidepressants, selective serotonin reuptake inhibitors, benzodiazepines, non-steroidal anti-inflammatory drugs, and cocaine are discussed in detail. Specific aspects of common paediatric poisonings are reviewed.

Evaluation of the high specificity Screening Program (C-20-1) of the Frequency Doubling Technology (FDT) perimeter in clinical practice

AIMS

To compare the efficacy of the high specificity Frequency Doubling Technology (FDT) Perimeter Screening Program (C-20-1) to standard threshold automated perimetry in the diagnosis of open-angle glaucoma.

METHODS

A total of 100 consecutively presenting patients attending a glaucoma clinic who volunteered for the study (approximately 30% of whom were attending for an initial visit) were examined with the FDT C-20-1 Screening Program and with the Humphrey Field Analyzer (HFA) SITA Fast algorithm and Program 24-2.

RESULTS

Of the patients, 17 were excluded due to unreliable visual field results or non-glaucomatous ocular abnormalities. In all, 10 patients were diagnosed as normal, 54 with open-angle glaucoma, eight with ocular hypertension, and 11 as glaucoma suspects. Of the 54 glaucomatous patients, 45 exhibited high-tension glaucoma and nine normal tension glaucoma. Perimetry with the HFA gave a sensitivity of 81.5% for the combined category of glaucoma and glaucoma suspect and a specificity of 83.3% for the combined category of normal and ocular hypertension. Perimetry with the FDT gave a sensitivity of 74.5% and a specificity of 85.2% compared to that of the HFA.

CONCLUSION

In the detection of glaucoma, Program C-20-1 of the FDT perimeter exhibits high specificity. It exhibits low sensitivity for the detection of mild loss but high sensitivity for advanced field loss relative to Program 24-2 and the SITA Fast algorithm of the HFA.

Responsive brushes and gels as components of soft nanotechnology

Progress in the development of generic molecular devices based on responsive polymers is discussed. Characterisation of specially synthesised polyelectrolyte gels, "grafted from" brushes and triblock copolymers is reported. A Landolt pH-oscillator, based on bromate/ sulfite/ferrocyanide, with a room temperature period of 20 min and a range of 3.1 < pH < 7.0, has been used to drive periodic oscillations in volume in a pH responsive hydrogel. The gel is coupled to the reaction and changes volume by a factor of at least 6. A continuously stirred, constant volume, tank reactor was set-up on an optical microscope and the reaction pH and gel size monitored. The cyclic force generation of this system has been measured directly in a modified JKR experiment. The responsive nature of polyelectrolyte brushes, grown by surface initiated ATRP, have been characterised by scanning force microscopy, neutron reflectometry and single molecule force measurements. Triblock copolymers, based on hydrophobic end-blocks and either polyacid or polybase mid-block, have been used to produce polymer gels where the deformation of the molecules can be followed directly by SAXS and a correlation between molecular shape change and macroscopic deformation has been established. The three systems studied allow both the macroscopic and a molecular response to be investigated independently for the crosslinked gels and the brushes. The triblock copolymers demonstrate that the individual response of the polyelectrolyte molecules scale-up to give the macroscopic response of the system in an oscillating chemical reaction.

Hepatocellular damage from non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for the management of rheumatological disorders, and as analgesics and antipyretics. Hepatotoxicity is an uncommon, but potentially lethal complication, which usually occurs within 12 weeks of starting therapy. It can occur with all NSAIDs, but appears to be more common with diclofenac and particularly sulindac. Female patients aged >50 years, with autoimmune disease, and those on other potentially hepatotoxic drugs, appear to be particularly susceptible. Liver function test abnormalities generally settle within 4-6 weeks of stopping the causative drug. However, some patients may develop acute liver failure and successful orthotopic liver transplantation may be undertaken in such patients. Recent in vitro animal studies have shown that the mechanism of diclofenac toxicity relates both to impairment of ATP synthesis by mitochondria, and to production of active metabolites, particularly n,5-dihydroxydiclofenac, which causes direct cytotoxicity. Mitochondrial permeability transition (MPT) has also been shown to be important in diclofenac-induced liver injury, resulting in generation of reactive oxygen species, mitochondrial swelling and oxidation of NADP and protein thiols. Physicians and hepatologists must be vigilant to the hepatotoxic potential of any NSAID, as increased awareness, surveillance and reporting of these events will lead to a better understanding of the risk factors and the pathophysiology of NSAID-related hepatotoxicity.