A122 MINIMALLY INVASIVE ENDOSCOPIC RESECTION TECHNIQUES FOR ANORECTAL JUNCTION NEOPLASIA: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

The management of neoplastic lesions at the anorectal junction remains debated. Endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) have emerged as the primary endoscopic modalities of choice.

Purpose

We sought to compare the performance of ESD and EMR in resection of anorectal neoplasia.

Method

Two authors independently searched MEDLINE, EMBASE and Cochrane Libraries (Jan 2000 – Aug 2021) for citations evaluating the performance of endoscopic resection techniques (ESD, EMR) for lesions involving the anorectal junction (defined as within 20mm of the dentate line). The frequencies and 95% confidence intervals (95% CI) of technical success (complete removal of all neoplastic tissue at index procedure), clinically significant post-endoscopic resection bleeding (CSPEB), delayed perforation, recurrence and referral to surgery were assessed using random-effects modelling.

Result(s)

We included 11 studies (total 563 patients: 414 ESD, 149 EMR) of which nine were ESD and two were EMR studies. Technical success was achieved in 97.2% overall (95% CI 94.8%-98.5%, ESD 97.5% and EMR range 93.9%-98.0%). Clinically significant post-endoscopic resection bleeding occurred in 4.3% (95% CI 1.6%-11.1%, ESD 3.0% and EMR range 8.2%-11.0%). Delayed perforation was not identified. Recurrence at first screening colonoscopy occurred in 4.8% (95% CI 1.9%-11.7%, ESD 3.0% and EMR range 15.4%-18.4%). Referral to surgery for any reason occurred in 5.9% (95% CI 4.3%-8.0%, ESD 6.9%, EMR range 2.0%-3.0%).

Conclusion(s)

ESD and EMR demonstrate high frequencies of technical success but may have different rates of adverse events and recurrence. More studies investigating lesions at the anorectal junction should be conducted including head-to-head analyses between ESD and EMR for low-risk anorectal junction neoplasia.

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Disclosure of Interest

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A105 ENDOSCOPIC MUCOSAL RESECTION AND ENDOSCOPIC SUBMUCOSAL DISSECTION FOR ILEOCECAL VALVE NEOPLASIA: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Neoplastic lesions at the ileocecal valve (ICV) represent a complex lesion subgroup given the unique anatomical characteristics of this location. Both endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are established techniques for colorectal neoplasia but comparative analyses for ICV lesions are lacking.

Aims

Evaluate the performance of EMR and ESD for ICV neoplasia.

Methods

Between Jan 2000 to Aug 2021, two authors independently searched MEDLINE, EMBASE and Cochrane Libraries for relevant citations evaluating the performance of either EMR and/or ESD for ICV neoplasia; defined as lesions involving at least one component of the ICV complex. The rate of technical success (complete removal of all neoplastic tissue during index procedure of those lesions deemed amenable to endoscopic resection), clinically significant post-endoscopic resection bleeding (CSPEB), delayed perforation, and recurrence were assessed. Meta-analysis was performed using a random-effects model.

Results

Nine studies (367 patients, 252 EMR, 115 ESD) were included in the analysis. Successful removal of all visible neoplastic tissue of those deemed amenable to endoscopic resection was 98.1% (EMR 99.6%, ESD 97.4%). Of note, only 2 studies, both assessing EMR, provided data on lesions which were not considered for endoscopic resection ranging from 5.6–23.7%. Average procedure time ranged from 45–49 minutes for EMR and 52–191 minutes for ESD. Clinically significant post-endoscopic resection bleeding occurred in 6.2% (EMR 9.4%, ESD 4.4%). Delayed perforation occurred in 0.6% (EMR 0.4%, ESD 2.0%). Recurrence occurred in 3.1% (EMR 13.2%, ESD 1.9%).

Conclusions

Endoscopic resection, both with EMR and ESD, demonstrates high technical success and good adverse event profiles amongst ICV neoplasia deemed amenable for endoscopic resection.

Funding Agencies

None

A123 MINIMALLY INVASIVE ENDOSCOPIC RESECTION TECHNIQUE PERFORMANCE FOR PERI-APPENDICEAL COLORECTAL NEOPLASIA: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Minimally invasive endoscopic resection techniques, including endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD) and endoscopic full-thickness resection (EFTR) have revolutionized the management of peri-appendiceal colorectal neoplasia. However, questions remain about their comparative performance.

Aims

We sought to evaluate the performance of EMR, ESD and EFTR for peri-appendiceal colorectal neoplasia.

Methods

Two authors independently searched MEDLINE, EMBASE and Cochrane Libraries (Jan 2000 – Aug 2021) for citations evaluating the performance of endoscopic resection techniques (EMR, ESD, EFTR) for peri-appendiceal colorectal neoplasia (defined as those involving or in close proximity to the appendiceal orifice). The incidence rates and 95% confidence intervals (95% CI) of technical success (complete removal of all neoplastic tissue at index procedure), clinically significant post-endoscopic resection bleeding (CSPEB), delayed perforation, recurrence and referral to surgery were assessed using random-effects modelling.

Results

12 studies were included in the analysis (479 patients: 185 EMR, 171 ESD, 123 EFTR). Technical success was achieved in 93.5% (95% CI 90.9%-95.4%, EMR 93.5%, ESD 94.1%, EFTR 92.7%). Clinically significant post-endoscopic resection bleeding occurred in 1.3% (95% CI 0.4%-4.3%, EMR 3.8%, ESD 1.2%, EFTR 0%). Delayed perforation occurred in 1.9% (95% CI 0.9%-3.9%, EMR 0%, ESD 2.4%, EFTR 2.4%). Recurrence occurred in 5.7% (95% CI 2.3%-13.8%, EMR 14.3%, ESD 0.2%, EFTR 12.2–14.3%). Referral to surgery occurred in 9.0% (95% CI 6.7%-12.0%, EMR 8.1%, ESD 9.5%, EFTR 9.8%).

Conclusions

Minimally invasive endoscopic resection techniques including EMR, ESD and EFTR demonstrate high frequencies of technical success with comparable adverse event profiles. They should now be viewed as first-line therapeutic modalities for the management of peri-appendiceal colorectal neoplasia.

Funding Agencies

None

A164 PATTERNS IN MEDICAL THERAPY AND CLINICAL OUTCOMES IN PATIENTS WITH CONCOMITANT INFLAMMATORY BOWEL DISEASE AND PRIMARY SCLEROSING CHOLANGITIS: A SINGLE CENTRE RETROSPECTIVE ANALYSIS

Background

Inflammatory bowel disease (IBD) in patients with primary sclerosing cholangitis (PSC) is characterized by pancolitis with rectal sparing and is associated with an increased risk of colorectal and biliary malignancies. Currently, pharmacologic management of IBD in the setting of PSC is the same as in IBD alone.

Aims

To assess patterns in medical therapy, and incidence of adverse outcomes in patients with concomitant IBD and PSC.

Methods

A retrospective review was conducted on all PSC-IBD patients followed between January 2010 and June 2018. The Endoscopic Mayo Score was used to grade IBD severity in PSC-ulcerative colitis (UC).

Results

69 patients were identified, 44 (63.8%) were male. The mean ages of IBD and PSC diagnosis were 28.6 (SD 14.9) and 37.0 (SD 18.9) years, respectively. The median length of follow up was 12 (range 2–49) years. 52 (75.4%) patients had UC, and 17 (24.6%) had Crohn’s disease (CD). 28 (87.5%) PSC-UC patients had pancolitis, and 4 (12.5 %) had proctitis. Among those with pancolitis, 8 (28.6%) had relative rectal sparing. 4 (14.3%) patients had more severe inflammation proximally, whereas only 1 (3.6%) had more severe distal inflammation. 23 (82.1%) patients had the same degree of inflammation throughout. 14 (93.3%) PSC-CD patients had colitis/ileocolitis and 1 (6.7%) had ileitis. Among those with PSC-UC, 16 (50.0%), 12 (37.5%), and 4 (12.5%) patients had grade 1, 2, and 3 disease, respectively. 62 (89.9%) PSC-IBD patients were treated with aminosalicylates, and 26 (37.7%) with biologics at some point in their IBD course. 26 (37.7%) were treated with aminosalicylates alone. 4 (5.8%) did not require any IBD therapy. Cholangiocarcinoma, colorectal cancer, and gallbladder cancer developed in 8 (11.6%), 1 (1.4%), and 1 (1.4%) PSC-IBD patients, respectively. 16 (23.2%) patients required partial or total colectomy. Indication for surgery was inflammation or stenosis, dysplasia, and neoplasia in 13 (81.3%), 2 (12.5%), and 1 (6.3%) patients, respectively.

Conclusions

The majority of this cohort had UC with mild disease activity. Pancolitis was common, with frequent rectal sparing and more severe right-sided inflammation. Despite the predominance of low-grade colitis, a large portion of patients required treatment with biologics. The incidence of adverse outcomes underscores the need for strict adherence to recommended surveillance practices. Low grade endoscopic activity, typical of the quiescent IBD course in PSC-IBD, may mask low grade histologic inflammation, which in turn may contribute to the increased risk of colonic neoplasia. Further studies are needed to determine the best management strategy for IBD in patients with PSC.

Funding Agencies

None

A147 PRIMARY COLONIC MANTLE CELL LYMPHOMA: A RARE ENTITY

Background

Mantle cell lymphoma (MCL) is an aggressive subtype of B-cell non-Hodgkin lymphoma (NHL), often diagnosed at later stages with secondary gastrointestinal (GI) involvement. Primary GI MCL is rare and is not often discussed in the literature.

Aims

To increase awareness of a rare condition that is likely to be encountered but can be challenging to diagnose.

Methods

Case report and review of the literature.

Results

Case Report

A 78-year-old man with multiple untreated vascular risk factors including atrial fibrillation and type 2 diabetes presented with acute onset left hemiplegia, dysarthria, and imaging consistent with a left pontine stroke. As part of his workup he underwent a CT abdomen/pelvis identifying an 11 x 5 cm intraluminal mass in the transverse colon.

Previous screening colonoscopies, for family history of colon cancer, were notable for tubular adenomas without high-grade dysplasia at 13, 12, 10, 7, and 2 years prior to admission. The patient had 16 pounds of weight loss without other constitutional symptoms, change in bowel habits or evidence of GI bleeding. Bloodwork was notable for microcytic anemia (Hemoglobin 91 g/L, MCV 75 fL), from a normal baseline one year prior, without other cytopenias. C-reactive protein (44 mg/L) and GGT (164 U/L) were elevated. Other liver enzymes, lactate dehydrogenase, and electrolytes were normal.

Colonoscopy revealed numerous polypoid lesions throughout the entire colon and a large non-obstructive mass with submucosal appearance in the transverse colon. Biopsies were taken from the large mass and one of the smaller polypoid lesions. Histology showed a sheet-like infiltrate of small lymphocytes within the lamina propria. Immunohistochemical staining was positive for CD20, BCL2, Cyclin D1, equivocal for CD5, and negative for BCL6 and CD3. Ki67 index approached 30%. A diagnosis of colonic MCL was made.

Literature Review

Primary MCL of the GI tract is rare, accounting for only 1 to 4% of all GI malignancies. There is a male and Caucasian predominance with a median age of 68 years at diagnosis. Presenting complaints may include abdominal pain, anorexia, and GI bleeding. Typical endoscopic features are small nodular or polypoid tumors, between 2mm and 2 cm in size, along one or more segments of the GI tract referred to as multiple lymphomatous polyposis (MLP). A single colonic mass is infrequently seen, highlighting the importance of endoscopy for diagnosis, as subtle findings may be missed on radiographic evaluation. Biopsies for immunohistochemistry are essential to distinguish MCL from other NHLs, as almost all cases express cyclin D1. Despite aggressive immunochemotherapy, prognosis is often poor due to MCL’s rapid progression and early relapse.

Conclusions

Primary GI MCL is a rare entity. Awareness is essential as evaluation and management differ from lymphoma at other sites, and other GI malignancies.

Funding Agencies

None

Death in the New Town: Edinburgh's hidden story of stonemasons' silicosis

The building of the Edinburgh New Town, from the mid-18th to the mid-19th centuries, was a major advance in harmonious and elegant town planning. However, there is anecdotal evidence that it led to the occurrence of an epidemic of silicosis/tuberculosis among the stonemasons. We have reviewed contemporary accounts of the episode and early records of the understanding of silicosis. We have also studied the lung of a contemporary stonemason, preserved in the museum of the Royal College of Surgeons of Edinburgh, and confirmed the presence of silico-tuberculosis in it. The evidence shows that a major epidemic did occur, caused by a combination of factors. The size of the undertaking attracted many stonemasons to Edinburgh over a period of almost 100 years, intensively cutting and dressing stone. The principal stone worked was a very high-quartz sandstone, derived from the local Craigleith quarry, having properties that made it desirable for prestige buildings. However, even before the construction of the New Town, Craigleith sandstone was notorious for its dustiness and the Edinburgh stonemasons worked the stone in unventilated sheds. Stonemasons appeared to be aware of the risk of their trade, but little was known about preventive measures. It appears it was assumed that the risks to stonemasons disappeared after the Craigleith quarry closed, the employers emphasising (without evidence) the lack of health risks in other quarries, and the tragic episode appears to have been forgotten. However, we point to the continuing occurrence of silicosis among stonemasons to the present day; the importance of remembering such episodes is stressed lest the lessons of the past be forgotten.

James Craufurd Gregory, 19th century Scottish physicians, and the link between occupation as a coal miner and lung disease

By the mid-19th century about 200,000 miners were employed in a UK coal mining industry still growing with the advances of the Industrial Revolution. Coal miners were long known to suffer poor health but the link to inhaling dust in the mines had not been made. In 1813 George Pearson was the first to suggest that darkening of lungs seen in normal individuals as they aged was caused by inhaled soot from burning oil, candles and coal, which were the common domestic sources of heat and light. In 1831 Dr James Craufurd Gregory first described black pigmentation and disease in the lungs of a deceased coal miner and linked this to pulmonary accumulation of coal mine dust. Gregory hypothesised that the black material seen at autopsy in the collier's lungs was inhaled coal dust and this was confirmed by chemical analysis carried out by Professor Sir Robert Christison. Gregory suggested that coal dust was the cause of the disease and warned physicians in mining areas to be vigilant for the disease. This first description of what came to be known as 'coal worker's pneumoconiosis' sparked a remarkable intellectual effort by physicians in Scotland, culminating in a large body of published work that led to the first understandings of this disease and its link to coalblackened lungs. This paper sets out the history of the role of Scottish physicians in gaining this understanding of coal worker's pneumoconiosis. It describes Gregory's case and the lung - recently discovered in the pathology collection of the Surgeons' Hall Museums, Edinburgh, where it has lain unnoticed for over 180 years - on which Gregory based his landmark paper.

Evaluation of hibergene loop-mediated isothermal amplification assay for detection of group B streptococcus in recto-vaginal swabs: a prospective diagnostic accuracy study

OBJECTIVES

To prospectively evaluate HiberGene's loop-mediated isothermal amplification (LAMP) assay for detection of group B streptococcus (GBS) in maternal recto-vaginal swabs and compare it with enrichment culture.

METHODS

Following ethical approval and informed written consent, two low vaginal and rectal swabs were obtained from 400 pregnant women. One swab was tested for GBS using the rapid LAMP assay (index test), the second swab was tested using enrichment culture (reference standard). Antimicrobial susceptibility testing was performed according to EUCAST guidelines.

RESULTS

There were 376 concordant results, 20 discordant and four invalid LAMP results. Among discordant results, six were LAMP negative/culture positive and 14 were LAMP positive/culture negative. The sensitivity was 92.2%, specificity 95.6%, positive predictive value 83.5% and negative predictive value 98.1%. The prevalence of GBS carriage was 19.25% (77/400). Forty-eight of 77 GBS-positive women were colonized vaginally (62.3%) and 70 were colonized rectally (90.9%). Erythromycin resistance was 22.4% (17/76) and clindamycin resistance was 17.1% (13/76).

CONCLUSIONS

The LAMP assay is a rapid and simple test with results available in approximately 1 h compared with 48 h for culture. The test has good sensitivity and specificity compared with enrichment culture. This test can be used for rapid antenatal GBS screening.

Abstract P4-14-26: Phase I expansion of S-222611, a reversible inhibitor of EGFR and HER2, in advanced solid tumors, including HER2-positive breast cancer patients with brain metastases

BACKGROUND

S-222611 is an oral, reversible ErbB tyrosine kinase inhibitor of EGFR and HER2 with potent pre-clinical activity. MTD was not reached during the dose-escalation phase, (maximum dose 1600 mg QD). PK and efficacy data supported a daily dose of 800 mg. An expansion cohort of patients has been treated to further explore safety and efficacy.

METHODS

Subjects with advanced solid tumors expressing EGFR and/or overexpressing HER2 were enrolled. S-222611 800 mg daily was administered until disease progression or unacceptable toxicity.

RESULTS

76 patients were included in this phase 1 expansion cohort with a variety of tumor types. Dose reduction was required because of adverse events in 15 patients; the most frequent of which being diarrhea and elevated bilirubin. Two patients discontinued treatment due to drug- related adverse events. Of the 25 patients with HER2-positive metastatic breast cancer (MBC), 4 partial responses were observed, and prolonged stable disease (≥ 6 months) was observed in 3 additional patients. These 25 patients had received prior HER2-directed therapy as shown in Table 1.

Table 1. Prior therapies received by patients with HER2-positive MBCPrior therapyn (%)Trastuzumab22 (88)T-DM13 (12)Lapatinib16 (64)Chemotherapy23 (92)

Six of these patients had brain metastases, in whom 1 intracranial response and 2 prolonged stable disease (≥ 6 months) were observed (Table 2).

Table 2. HER2-positive MBC patients with brain metastases - best overall response to S-222611Pts #HER2 IHCBrain metastasesBest overall response (RECIST 1.1)Patient 13+Target lesionPRPatient 23+Target lesionSD (≥12 M)Patient 33+Target lesionSD (6.0 M)Patient 43+Non-target lesionSD (4.7 M)Patient 53+Non-target lesionSD (3.3 M)Patient 63+Non-target lesionNE

The patient showing intracranial response was previously treated with lapatinib and capecitabine after diagnosis of BM.

CONCLUSIONS

S-222611 was well tolerated at a dose of 800 mg once daily. Anti-tumour activity, including shrinkage of brain metastases, was evident in a heavily pre-treated population of patients with HER2-positive breast cancer.

Citation Format: Baird RD, Arkenau H-T, Deva S, Cresti N, Garcia-Corbacho J, Hogarth L, Frenkel E, Kawaguchi K, Arimura A, Donaldson K, Posner J, Sarker D, Jodrell D, Plummer R, Spicer J, Italiano A. Phase I expansion of S-222611, a reversible inhibitor of EGFR and HER2, in advanced solid tumors, including HER2-positive breast cancer patients with brain metastases. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-26.

The in vitro respiratory toxicity of cristobalite-bearing volcanic ash

Ash from dome-forming volcanoes poses a unique hazard to millions of people worldwide due to an abundance of respirable cristobalite, a crystalline silica polymorph. Crystalline silica is an established respiratory hazard in other mixed dusts, but its toxicity strongly depends on sample provenance. Previous studies suggest that cristobalite-bearing volcanic ash is not as bio-reactive as may be expected for a dust containing crystalline silica. We systematically address the hazard posed by volcanic cristobalite by analysing a range of dome-related ash samples, and interpret the crystalline silica hazard according to the mineralogical nature of volcanic cristobalite. Samples are sourced from five well-characterized dome-forming volcanoes that span a range of magmatic compositions, specifically selecting samples rich in cristobalite (up to 16wt%). Isolated respirable fractions are used to investigate the in vitro response of THP-1 macrophages and A549 type II epithelial cells in cytotoxicity, cellular stress, and pro-inflammatory assays associated with crystalline silica toxicity. Dome-related ash is minimally reactive in vitro for a range of source compositions and cristobalite contents. Cristobalite-based toxicity is not evident in the assays employed, supporting the notion that crystalline silica provenance influences reactivity. Macrophages experienced minimal ash-induced cytotoxicity and intracellular reduction of glutathione; however, production of IL-1β, IL-6 and IL-8 were sample-dependent. Lung epithelial cells experienced moderate apoptosis, sample-dependent reduction of glutathione, and minimal cytokine production. We suggest that protracted interaction between particles and epithelial cells may never arise due to effective clearance by macrophages. However, volcanic ash has the propensity to incite a low, but significant, and sample-dependent response; the effect of this response in vivo is unknown and prolonged exposure may yet pose a hazard.

Mathematical Modeling to Predict the Responses to Poorly Soluble Particles in Rat Lungs

Rat inhalation experiments with titanium dioxide (TiO2) and barium sulfate (BaSO4), at concentrations calculated to produce similar volumetric lung burden for both dusts, showed overload with TIO2 but not for BaSO4 "Overload," occurring in rats exposed to "low-toxicity" dusts at high concentrations, is characterized by a rapid deterioration in clearance and onset of inflammation. Impairment of alveolar macrophage (AM) mediated clearance, dust translocation to the lymph nodes, and neutrophil (PMN) recruitment for both dusts were better predicted by the lung burden expressed as surface area rather than mass or volume. A mathematical model describing the translocation (in terms of particulate mass) of inhaled particles in various physiologically based pulmonary compartments was used to calculate pulmonary clearance when effective and also when impairment by overload leads to increased dust translocation to the lymph nodes. Our objectives were: (I) to modify this model to include the influence of particle surface area on clearance and interstitialization; (2) to extend the model to describe the PMN recruitment; and (3) to use the model to estimate the highest exposure level such that overload would be avoided in a chronic inhalation experiment with rats. In extrapolating down to no-overload concentrations, due account was taken of the observed interanimal variation (assuming this variation was mainly due to differences in inhaled dose). For TiO2 and BaSO4, with the given size distributions, the predicted concentrations at which 95% of the animals were expected to avoid overload were 3 mg m(-3) and 7.5 mg m(-3), respectively. The general quantitative relationships on the role of particle surface area and on the estimation of the no-overload level have important implications for setting standards for poorly soluble particles.

Nuclear Factor Kappa-B Activation by Particles and Fibers

In recent years, particle research has focused on activation pathways of transcription factors that are known to regulate genes whose abnormal expression is associated with the pathogenesis of particle-associated lung disorders such as fibrosis, cancer, COPD, and asthma. This article reviews the effects of different particles and fibers on the transcriptional activation of nuclear factor kappa-B (NF-kB), which is involved in the activation of a variety of proinflammatory genes. Particulates that have been found to activate NF-κB, include asbestos, man-made fibers, quartz, and ambient particulates, such as residual oil fly ashes (ROFA) and diesel exhaust particles (DEP). In line with this, a number of NF-κB-regulated genes have been found to be upregulated, such as tumour necrosis factor-alpha (TNFα), macrophage inflammatory protein-2 (MIP-2), the interleukins IL-6 and IL-8, cyclooxygenase- II (COX-II), and inducible nitric oxide synthase (iNOS). Important mechanisms involved in the activation of NF-kB by particles or fibers include a role for reactive oxygen species, arachidonic acid metabolism, and particle- or fiber-specific physiochemical properties (e.g., transition metals, fiber dimensions) in processes such as lipid peroxidation and (frustrated) phagocytosis. Intracellularly, NF-κB may be activated via several pathways, for example, involving protein kinase C, tyrosine kinase, or calpain. Future research on NF-κB activation by particles or fibers should aim to further identify these and other pathways and to determine the in vivo significance of this activation in the pathogenesis of lung disease.

Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis

BACKGROUND

Recurrent instability following a first-time anterior traumatic shoulder dislocation may exceed 26%. We systematically reviewed risk factors which predispose this population to events of recurrence.

METHODS

A systematic review of studies published before 1 July 2014. Risk factors which predispose recurrence following a first-time traumatic anterior shoulder dislocation were documented and rates of recurrence were compared. Pooled ORs were analysed using random-effects meta-analysis.

RESULTS

Ten studies comprising 1324 participants met the criteria for inclusion. Recurrent instability following a first-time traumatic anterior shoulder dislocation was 39%. Increased risk of recurrent instability was reported in people aged 40 years and under (OR=13.46), in men (OR=3.18) and in people with hyperlaxity (OR=2.68). Decreased risk of recurrent instability was reported in people with a greater tuberosity fracture (OR=0.13). The rate of recurrent instability decreased as time from the initial dislocation increased. Other factors such as a bony Bankart lesion, nerve palsy and occupation influenced rates of recurrent instability.

CONCLUSIONS

Sex, age at initial dislocation, time from initial dislocation, hyperlaxity and greater tuberosity fractures were key risk factors in at least two good quality cohort studies resulting in strong evidence as concluded in the GRADE criteria. Although bony Bankart lesions, Hill Sachs lesions, occupation, physiotherapy treatment and nerve palsy were risk factors for recurrent instability, the evidence was weak using the GRADE criteria-these findings relied on poorer quality studies or were inconsistent among studies.

Phase 1 dose-escalation study of S-222611, an oral reversible dual tyrosine kinase inhibitor of EGFR and HER2, in patients with solid tumours

BACKGROUND

S-222611 is a reversible inhibitor of EGFR, HER2 and HER4 with preclinical activity in models expressing these proteins. We have performed a Phase 1 study to determine safety, maximum tolerated dose (MTD), pharmacokinetic profile (PK) and efficacy in patients with solid tumours expressing EGFR or HER2.

PATIENTS AND METHODS

Subjects had advanced tumours not suitable for standard treatment, expressing EGFR or HER2, and/or with amplified HER2. Daily oral doses of S-222611 were escalated from 100mg to 1600 mg. Full plasma concentration profiles for drug and metabolites were obtained.

RESULTS

33 patients received S-222611. It was well tolerated, and the most common toxicities, almost all mild (grade 1 or 2), were diarrhoea, fatigue, rash and nausea. Only two dose-limiting toxicities occurred (diarrhoea and rash), which resolved on interruption. MTD was not reached. Plasma exposure increased with dose up to 800 mg, exceeding levels eliciting pre-clinical responses. The plasma terminal half-life was more than 24h, supporting once daily dosing. Responses were seen over a wide range of doses in oesophageal, breast and renal tumours, including a complete clinical response in a patient with HER2-positive breast carcinoma previously treated with lapatinib and trastuzumab. Four patients have remained on treatment for more than 12 months. Downregulation of pHER3 was seen in paired tumour biopsies from a responding patient.

CONCLUSIONS

Continuous daily oral S-222611 is well tolerated, modulates oncogenic signalling, and has significant antitumour activity. The recommended Phase 2 dose, based on PK and efficacy, is 800 mg/day.

Effect of wood smoke exposure on vascular function and thrombus formation in healthy fire fighters

BACKGROUND

Myocardial infarction is the leading cause of death in fire fighters and has been linked with exposure to air pollution and fire suppression duties. We therefore investigated the effects of wood smoke exposure on vascular vasomotor and fibrinolytic function, and thrombus formation in healthy fire fighters.

METHODS

In a double-blind randomized cross-over study, 16 healthy male fire fighters were exposed to wood smoke (~1 mg/m³ particulate matter concentration) or filtered air for one hour during intermittent exercise. Arterial pressure and stiffness were measured before and immediately after exposure, and forearm blood flow was measured during intra-brachial infusion of endothelium-dependent and -independent vasodilators 4-6 hours after exposure. Thrombus formation was assessed using the ex vivo Badimon chamber at 2 hours, and platelet activation was measured using flow cytometry for up to 24 hours after the exposure.

RESULTS

Compared to filtered air, exposure to wood smoke increased blood carboxyhaemoglobin concentrations (1.3% versus 0.8%; P < 0.001), but had no effect on arterial pressure, augmentation index or pulse wave velocity (P > 0.05 for all). Whilst there was a dose-dependent increase in forearm blood flow with each vasodilator (P < 0.01 for all), there were no differences in blood flow responses to acetylcholine, sodium nitroprusside or verapamil between exposures (P > 0.05 for all). Following exposure to wood smoke, vasodilatation to bradykinin increased (P = 0.003), but there was no effect on bradykinin-induced tissue-plasminogen activator release, thrombus area or markers of platelet activation (P > 0.05 for all).

CONCLUSIONS

Wood smoke exposure does not impair vascular vasomotor or fibrinolytic function, or increase thrombus formation in fire fighters. Acute cardiovascular events following fire suppression may be precipitated by exposure to other air pollutants or through other mechanisms, such as strenuous physical exertion and dehydration.

Principal component and causal analysis of structural and acute in vitro toxicity data for nanoparticles

Structure toxicity relationship analysis was conducted using principal component analysis (PCA) for a panel of nanoparticles that included dry powders of oxides of titanium, zinc, cerium and silicon, dry powders of silvers, suspensions of polystyrene latex beads and dry particles of carbon black, nanotubes and fullerene, as well as diesel exhaust particles. Acute in vitro toxicity was assessed by different measures of cell viability, apoptosis and necrosis, haemolytic effects and the impact on cell morphology, while structural properties were characterised by particle size and size distribution, surface area, morphology, metal content, reactivity, free radical generation and zeta potential. Different acute toxicity measures were processed using PCA that classified the particles and identified four materials with an acute toxicity profile: zinc oxide, polystyrene latex amine, nanotubes and nickel oxide. PCA and contribution plot analysis then focused on identifying the structural properties that could determine the acute cytotoxicity of these four materials. It was found that metal content was an explanatory variable for acute toxicity associated with zinc oxide and nickel oxide, while high aspect ratio appeared the most important feature in nanotubes. Particle charge was considered as a determinant for high toxicity of polystyrene latex amine.

Abstract P4-12-24: Phase I trial of S-222611, a dual tyrosine kinase inhibitor of EGFR and HER2, with preliminary evidence of efficacy in patients (pts) with heavily-pretreated HER2-positive metastatic breast cancer

Background and rationale: S-222611 is a novel, oral, reversible inhibitor of EGFR, HER2 and HER4 with an improved preclinical profile compared with first-generation pan-HER inhibitors.

Research objectives: We conducted a phase I study to determine safety, maximum tolerated dose (MTD), pharmacokinetics (PK), pharmacodynamics (PD) and preliminary efficacy in pts with solid tumors expressing EGFR or HER2.

Patients and methods: Pts with advanced solid tumors and biopsies confirming EGFR and/or HER2 expression were treated with continuous daily oral doses of S-222611. The dose of S-222611 was escalated in cohorts of at least 3 pts from 100mg to 1600mg. PK profiles were obtained in all pts, and PD assays for pEGFR, pHER2 and pHER3 were performed on paired tumor biopsies in selected pts.

Results: A total of 50 pts have been treated to-date; age 25-80y; 20 female; 13 with HER2-positive metastatic breast cancer (HER2+ MBC). S-222611 was generally well tolerated with two dose-limiting toxicities in the dose-escalation phase: rash at 1200mg; diarrhea at 1600mg. MTD was not defined. Diarrhea was the most frequent toxicity, but was rarely worse than grade 1/2. Nausea, rash, anorexia and fatigue were also seen. Bilirubin rises with normal transaminases were observed. Plasma concentrations of S-222611 increased with dose up to 800mg, which was the dose selected for the expansion phase. Steady state values of Cmax and AUC0-24 at this dose were in the effective range of concentrations in mouse models. Average t½ of 33h was consistent with once daily dosing. Tumor responses were seen over the full dose range tested (100-1600mg), with four pts on treatment for &gt;12 months. Out of 13 HER2+ MBC pts, one clinical complete response (CR) was observed for &gt;12 months, and four partial responses (PRs) were also seen (2 confirmed, 2 unconfirmed), yielding an overall response rate of 38% in this small group (Table 1). All 5 responding patients had previously progressed on trastuzumab (T); 4 of them had also progressed on lapatinib (L); and one patient had progressed on T, L and T-DM1. Out of 6 breast patients with PD results available, the 3 pts with a decrease in pHER3 all responded, whereas the 3 pts with no change or increase in pHER3 all had disease progression.

Conclusion: S-222611 was well tolerated in doses up to 1600mg daily with diarrhea, nausea and rash being readily manageable. Significant antitumor activity has been observed in patients with heavily pre-treated HER2+ MBC, including those progressing on prior T, L and T-DM1. Rates of grade 3 diarrhea appear markedly lower than those reported for other second-generation pan-HER TKIs. The recommended phase 2 dose, based on PK and clinical activity, is 800mg/day.

Table 1. HER2+ MBC pts with tumor shrinkage after S-222611 treatmentPatient numberPrior progression on trastuzumab-based regimenPrior progression on lapatinib-based regimenBest responseMonths on treatment (at time of data lock)S01014YYclinical CR20.3m (ongoing)S03034YNconfirmed PR11.5m (ongoing)S04046YYconfirmed PR6.0m (ongoing)S01030YYunconfirmed PRwithdrawn at 3.7m with progressionS01047YYunconfirmed PR4.8m (ongoing)

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-24.

Physicochemical and toxicological profiling of ash from the 2010 and 2011 eruptions of Eyjafjallajökull and Grímsvötn volcanoes, Iceland using a rapid respiratory hazard assessment protocol

The six week eruption of Eyjafjallajökull volcano in 2010 produced heavy ash fall in a sparsely populated area of southern and south eastern Iceland and disrupted European commercial flights for at least 6 days. We adopted a protocol for the rapid analysis of volcanic ash particles, for the purpose of informing respiratory health risk assessments. Ash collected from deposits underwent a multi-laboratory physicochemical and toxicological investigation of their mineralogical parameters associated with bio-reactivity, and selected in vitro toxicology assays related to pulmonary inflammatory responses. Ash from the eruption of Grímsvötn, Iceland, in 2011 was also studied. The results were benchmarked against ash from Soufrière Hills volcano, Montserrat, which has been extensively studied since the onset of eruptive activity in 1995. For Eyjafjallajökull, the grain size distributions were variable: 2-13 vol% of the bulk samples were <4 µm, with the most explosive phases of the eruption generating abundant respirable particulate matter. In contrast, the Grímsvötn ash was almost uniformly coarse (<3.5 vol%<4 µm material). Surface area ranged from 0.3 to 7.7 m2 g(-1) for Eyjafjallajökull but was very low for Grímsvötn (<0.6 m2 g(-1)). There were few fibre-like particles (which were unrelated to asbestos) and the crystalline silica content was negligible in both eruptions, whereas Soufrière Hills ash was cristobalite-rich with a known potential to cause silicosis. All samples displayed a low ability to deplete lung antioxidant defences, showed little haemolysis and low acute cytotoxicity in human alveolar type-1 like epithelial cells (TT1). However, cell-free tests showed substantial hydroxyl radical generation in the presence of hydrogen peroxide for Grímsvötn samples, as expected for basaltic, Fe-rich ash. Cellular mediators MCP-1, IL-6, and IL-8 showed chronic pro-inflammatory responses in Eyjafjallajökull, Grímsvötn and Soufrière Hills samples, despite substantial differences in the sample mineralogy and eruptive styles. The value of the pro-inflammatory profiles in differentiating the potential respiratory health hazard of volcanic ashes remains uncertain in a protocol designed to inform public health risk assessment, and further research on their role in volcanic crises is warranted.

Vascular access type and risk of mortality in a national prospective cohort of haemodialysis patients

BACKGROUND

Central venous catheters (CVC) are a potential source of bacteraemia and have been associated with increased mortality in haemodialysis patients. We aimed to investigate the relationships between haemodialysis vascular access, taking into account changes in vascular access type during patients' lives, and cause specific mortality risk in a national cohort of dialysis patients.

METHODS

Prospective cohort study including all patients receiving haemodialysis in Scotland at annual cross sectional surveys in 2009, 2010 and 2011. Data were collected through the Scottish Renal Registry and by a structured review of case records following death. Cox proportional hazards regression and multivariable logistic regression were used to model survival and risk of death from septicaemia respectively.

RESULTS

Of a cohort of 2666 patients, 873 (32%) died during follow-up. After case-mix adjustment, patients using only tunnelled CVC during follow-up had a higher risk of all cause mortality across all strata of prior renal replacement therapy exposure [adjusted hazard ratio (HR): 1.83-2.08]. Case-mix adjusted risks of cardiovascular death (adjusted HR: 2.20-2.95) and infection-related death (adjusted HR: 3.10-3.63) were also higher in this group. Patients using tunnelled CVCs during follow-up and prior to death had 6.9-fold higher odds of death from septicaemia compared with those using only arteriovenous fistulae or grafts.

CONCLUSION

Compared with an arteriovenous fistula or graft, sustained use of tunnelled CVCs for vascular access is associated with higher risks of all-cause, cardiovascular and infection-related mortality.

Investigating the potential for interaction between the components of PM(10)

The adverse health effects of elevated exposures to PM(10) (particulate matter collected through a size selective inlet with an efficiency of 50% for particles with an aerodynamic diameter of 10 μm) in relation to morbidity and mortality, especially in susceptible individuals, are now well recognised. PM(10) consists of a variable cocktail of components differing in chemical composition and size. Epidemiological and toxicological data suggest that transition metals and ultrafine particles are both able to drive the cellular and molecular changes that underlie PM(10)-induced inflammation and so worsen disease status. Toxicological evidence also suggest roles for the biological components of PM(10) including volatile organic compounds (VOC's), allergens and bacterial-derived endotoxin. Many of these components, in particular transition metals, ultrafine particles, endotoxin and VOC's induce a cellular oxidative stress which initiates an intracellular signaling cascade involving the activation of phosphatase and kinase enzymes as well as transcription factors such as nuclear factor kappa B. Activation of these signaling mechanisms results in an increase in the expression of proinflammatory mediators, and hence enhanced inflammation. Given that many of the components of PM(10) stimulate similar or even identical intracellular signaling pathways, it is conceivable that this will result in synergistic or additive interactions so that the biological response induced by PM(10) exposure is a response to the composition rather than the mass alone. A small number of studies suggest that synergistic interactions occur between ultrafine particles and transition metals, between particles and allergens, and between particles and VOC's. Elucidation of the consequences of interaction between the components of PM(10) in relation to their biological activity implies huge consequences for the methods used to monitor and to legislate pollution exposure in the future, and may drive a move from mass based measurements to composition.

Effect of coating with lung lining fluid on the ability of fibres to produce a respiratory burst in rat alveolar macrophages

The aim of the study was to develop a simple short-term in vitro assay which would allow us to predict the pathogenicity of fibres based on data already available from in vivo studies. Fibres were used naked (uncoated) or coated with rat IgG, or rat or sheep surfactant. The fibres were used to stimulate superoxide anion release by rat alveolar macrophages. Binding of fibres to rat alveolar macrophages was assessed by optical microscopy. Fibres used in the naked state produced little or no stimulation of superoxide anion from rat alveolar macrophages. When fibres were coated with rat IgG there was a significant increase in superoxide release for all fibre types with the exception of RCF4 and Code 100/475. When fibres were coated with rat or sheep surfactant, there was suppression of the respiratory burst for all fibre types. The observed suppression was not due to a scavenging effect by the surfactant itself, because xanthine/xanthine oxidase generated superoxide was unaffected by surfactant. The suppressive effect was shown to act directly on the macrophages. Comparing naked and coated fibres for their ability to bind to macrophages, it was shown that in general more coated fibres were bound and that increased binding was associated with suppressed superoxide release for both types of surfactant-coated fibres. It was concluded that the nature of the fibre coating is the main factor influencing the interaction between fibres and macrophages. The type of binding through different receptors may either stimulate or switch off the respiratory burst. The assay used here does not, however, allow any predictions to be made regarding the pathogenicity of fibres.

The role of oxidative stress in the prolonged inhibitory effect of ultrafine carbon black on epithelial cell function

Respired ultrafine particles induce a greater inflammation in rat lungs than fine particles; we have hypothesized that this is due to their comparatively huge number and surface area for the production of free radicals. We tested this hypothesis by studying the effects of fine and ultrafine (uf) carbon black (CB) particles in comparison with quartz on A549 human type II alveolar epithelial cells, particularly with respect to the oxidative properties of these particles. Treatment with fine CB (diameter 260nm), and quartz (up to 0.78mug/mm(2)) for 24 hours significantly (P<0.05) decreased the A549 cells metabolic competence, as measured by the ability to reduce MTT to a formazan product. The inhibitory effects of uf CB only became significantly different (P<0.05) relative to the control at 48 hours, by which time the effects of fine CB and quartz were no longer significant. The inhibition of MTT reduction by uf CB was prevented by the hydroxyl radical scavenger mannitol (2mm). In addition, measurement of reactive oxygen species production using supercoiled plasmid DNA showed that uf CB exhibited significantly more free radical activity than fine CB (P<0.05). In the absence of serum, uf CB depleted reduced glutathione at 6 hours (P<0.008). In contrast, CB did not significantly alter reduced or oxidized glutathione. Hence, compared with fine CB, uf CB exhibited greater free radical activity, greater inhibition of the reduction of MTT at 48 hours (prevented by mannitol) and a depletion of reduced glutathione. These results suggest that uf CB induces a greater oxidative stress than fine CB, and that this may play a role in the toxicological effects of this ultrafine particle.

Dental cone beam CT image quality possibly reduced by patient movement

Patient artefacts in dental cone beam CT scans can happen for various reasons. These range from artefacts from metal restorations to movement. An audit was carried out in the Glasgow Dental Hospital analysing how many scans showed signs of "motion artefact", and then to assess if there was any correlation between patient age and movement artefacts. Specific age demographics were then analysed to see if these cohorts were at a higher risk of "movement artefacts".

The challenges of renal replacement therapy and renal palliative care in the elderly

The main aim of this review is to let general practitioners and physicians understand what happens to older patients after referral to the renal service. Usually, most patients will be managed completely by the renal team, either because the patient requires dialysis or because conservative but specialised care is appropriate. The recent increase in dialysis rate can mostly be accounted for by older patients for whom such demanding treatment was previously thought to be contraindicated. The decision to dialyse the elderly still remains difficult, with recent data suggesting that if there are significant comorbidities the survival advantage of dialysis in patients over 75 years of age is unlikely to be more than four months. Towards the end of life, conservative treatment is not simply a decision not to dialyse, but comprises active disease management, including treatment of anaemia and other supportive care, which may become increasingly complex, e.g. pain relief with fentanyl and alfentanyl. Older patients who decide to accept dialysis treatment contend with all the usual end of life issues of older people. They have an additional option, denied to the rest of us, of dialysis withdrawal; this effectively allows them to die at a time of their choosing.

Type 1 pulmonary epithelial cells: a new compartment involved in the slow phase of particle clearance from alveoli

Whilst alveolar macrophages normally clear micron-sized particles from the respiratory units, nanoparticles might by-pass this mechanism and interact with alveolar epithelium. This letter discusses the possible role of alveolar epithelial type 1 cells in uptake and retention of nanoparticles within the alveolar septum. Accelerated apoptosis of nanoparticle-laden type 1 cells might trigger pro-inflammatory responses during apoptotic cell removal by macrophages. In the absence of clearance of apoptotic type 1 cells by this route, release of nanoparticles by dead type 1 cells and continued retention within the alveolar septum could lead to a slow process of nanoparticle removel from within the alveolar septum, rather than surface-only clearance. We suggest that this hypothesis warrants further research.

Quantification of the pathological response and fate in the lung and pleura of chrysotile in combination with fine particles compared to amosite-asbestos following short-term inhalation exposure

The marked difference in biopersistence and pathological response between chrysotile and amphibole asbestos has been well documented. This study is unique in that it has examined a commercial chrysotile product that was used as a joint compound. The pathological response was quantified in the lung and translocation of fibers to and pathological response in the pleural cavity determined. This paper presents the final results from the study. Rats were exposed by inhalation 6 h/day for 5 days to a well-defined fiber aerosol. Subgroups were examined through 1 year. The translocation to and pathological response in the pleura was examined by scanning electron microscopy and confocal microscopy (CM) using noninvasive methods.The number and size of fibers was quantified using transmission electron microscopy and CM. This is the first study to use such techniques to characterize fiber translocation to and the response of the pleural cavity. Amosite fibers were found to remain partly or fully imbedded in the interstitial space through 1 year and quickly produced granulomas (0 days) and interstitial fibrosis (28 days). Amosite fibers were observed penetrating the visceral pleural wall and were found on the parietal pleural within 7 days postexposure with a concomitant inflammatory response seen by 14 days. Pleural fibrin deposition, fibrosis, and adhesions were observed, similar to that reported in humans in response to amphibole asbestos. No cellular or inflammatory response was observed in the lung or the pleural cavity in response to the chrysotile and sanded particles (CSP) exposure. These results provide confirmation of the important differences between CSP and amphibole asbestos.

NiO and Co3O4 nanoparticles induce lung DTH-like responses and alveolar lipoproteinosis

Lung exposure to metal oxide nanoparticles (NPs) comprising soluble metal haptens may produce T-helper cell type 1 (Th1)- and Th17-associated delayed-type hypersensitivity (DTH) responses and pulmonary alveolar proteinosis (PAP). In order to study this, haptenic metal oxide NPs (NiO, Co(3)O(4), Cr(2)O(3) and CuO) were instilled into the lungs of female Wistar rats, and the immunoinflammatory responses were assessed at 24 h and 4 weeks post-instillation. Primary culture of alveolar macrophages from Wistar rats was used to evaluate the effect of the NPs on the ability to clear surfactant. NiO NPs induced chronic interstitial inflammation and pro-inflammatory Th1 and Th17 immune responses characterised by increases in the cytokines monocyte chemotactic protein (MCP)-1/CCL2, interleukin (IL)-12 p40, interferon-γ and IL-17A, whilst similar pathological responses induced by Co(3)O(4) NPs were associated with increases in MCP-1/CCL2 and IL-12 p40. However, neither Cr(2)O(3) nor CuO NPs elicited immunoinflammatory reactions. PAP was induced by both NiO and Co(3)O(4) NPs during the chronic phase. PAP was associated with over-production of surfactant by proliferation of type II cells and impaired clearance of surfactant by macrophages. These findings have implications for the risk management of occupational NP exposure and provide evidence that haptenic metal oxide NPs can induce chronic progressive lung immune responses via a DTH-like mechanism.

The pathological response and fate in the lung and pleura of chrysotile in combination with fine particles compared to amosite asbestos following short-term inhalation exposure: interim results

The pathological response and translocation of a commercial chrysotile product similar to that which was used through the mid-1970s in a joint compound intended for sealing the interface between adjacent wall boards was evaluated in comparison to amosite asbestos. This study was unique in that it presents a combined real-world exposure and was the first study to investigate whether there were differences between chrysotile and amosite asbestos fibers in time course, size distribution, and pathological response in the pleural cavity. Rats were exposed by inhalation 6 h/day for 5 days to either sanded joint compound consisting of both chrysotile fibers and sanded joint compound particles (CSP) or amosite asbestos. Subgroups were examined through 1-year postexposure. No pathological response was observed at any time point in the CSP-exposure group. The long chrysotile fibers (L > 20 microm) cleared rapidly (T(1/2) of 4.5 days) and were not observed in the pleural cavity. In contrast, a rapid inflammatory response occurred in the lung following exposure to amosite resulting in Wagner grade 4 interstitial fibrosis within 28 days. Long amosite fibers had a T(1/2) > 1000 days and were observed in the pleural cavity within 7 days postexposure. By 90 days the long amosite fibers were associated with a marked inflammatory response on the parietal pleural. This study provides support that CSP following inhalation would not initiate an inflammatory response in the lung, and that the chrysotile fibers present do not migrate to, or cause an inflammatory response in the pleural cavity, the site of mesothelioma formation.

Diesel exhaust particles override natural injury-limiting pathways in the lung

Induction of effective inflammation in the lung in response to environmental and microbial stimuli is dependent on cooperative signaling between leukocytes and lung tissue cells. We explored how these inflammatory networks are modulated by diesel exhaust particles (DEP) using cocultures of human monocytes with epithelial cells. Cocultures, or monoculture controls, were treated with DEP in the presence or absence of LPS or flagellin. Production of cytokines was explored by Western blotting and ELISA; cell signaling was analyzed by Western blotting. Here, we show that responses of epithelial cells to DEP are amplified by the presence of monocytes. DEP amplified the responses of cellular cocultures to very low doses of TLR agonists. In addition, in the presence of DEP, the responses induced by LPS or flagellin were less amenable to antagonism by the physiological IL-1 antagonist, IL-1ra. This was paralleled by the uncoupling of IL-1 production and release from monocytes, potentially attributable to an ability of DEP to sequester or degrade extracellular ATP. These data describe a model of inflammation where DEP amplifies responses to low concentrations of microbial agonists and alters the nature of the inflammatory milieu induced by TLR agonists.

Nanoparticles, human health hazard and regulation

New developments in technology usually entail some hazard as well as advantage to a society. Hazard of a material translates into risk by exposure of humans and/or their environment to the agent in question, and risk is reduced by control of exposure, usually guided by regulation based on understanding of the mechanisms of harm. We illustrate risks relating to the causation of diseases associated with exposure to aerosols of combustion particles and asbestos, leading to paradigms of particle toxicity, and discuss analogies with potential exposure to manufactured nanoparticles (NPs). We review the current understanding of the hazard of NPs derived from the new science of nanotoxicology and the limited research to date into human exposure to these particles. We identify gaps in knowledge relating to the properties of NPs that might determine toxicity and in understanding the most appropriate ways both to measure this in the laboratory and to assess it in the workplace. Nevertheless, we point out that physical principles governing the behaviour of such particles allow determination of practical methods of protecting those potentially exposed. Finally, we discuss the early steps towards regulation and the difficulties facing regulators in controlling potentially harmful exposures in the absence of sufficient scientific evidence.

Expert elicitation on ultrafine particles: likelihood of health effects and causal pathways

Background

Exposure to fine ambient particulate matter (PM) has consistently been associated with increased morbidity and mortality. The relationship between exposure to ultrafine particles (UFP) and health effects is less firmly established. If UFP cause health effects independently from coarser fractions, this could affect health impact assessment of air pollution, which would possibly lead to alternative policy options to be considered to reduce the disease burden of PM. Therefore, we organized an expert elicitation workshop to assess the evidence for a causal relationship between exposure to UFP and health endpoints.

Methods

An expert elicitation on the health effects of ambient ultrafine particle exposure was carried out, focusing on: 1) the likelihood of causal relationships with key health endpoints, and 2) the likelihood of potential causal pathways for cardiac events. Based on a systematic peer-nomination procedure, fourteen European experts (epidemiologists, toxicologists and clinicians) were selected, of whom twelve attended. They were provided with a briefing book containing key literature. After a group discussion, individual expert judgments in the form of ratings of the likelihood of causal relationships and pathways were obtained using a confidence scheme adapted from the one used by the Intergovernmental Panel on Climate Change.

Results

The likelihood of an independent causal relationship between increased short-term UFP exposure and increased all-cause mortality, hospital admissions for cardiovascular and respiratory diseases, aggravation of asthma symptoms and lung function decrements was rated medium to high by most experts. The likelihood for long-term UFP exposure to be causally related to all cause mortality, cardiovascular and respiratory morbidity and lung cancer was rated slightly lower, mostly medium. The experts rated the likelihood of each of the six identified possible causal pathways separately. Out of these six, the highest likelihood was rated for the pathway involving respiratory inflammation and subsequent thrombotic effects.

Conclusion

The overall medium to high likelihood rating of causality of health effects of UFP exposure and the high likelihood rating of at least one of the proposed causal mechanisms explaining associations between UFP and cardiac events, stresses the importance of considering UFP in future health impact assessments of (transport-related) air pollution, and the need for further research on UFP exposure and health effects.

A biopersistence study following exposure to chrysotile asbestos alone or in combination with fine particles

In designing a study to evaluate the inhalation biopersistence of a chrysotile asbestos that was used as a component of a joint-compound, a feasibility study was initiated to evaluate the short-term biopersistence of the chrysotile alone and of the chrysotile in combination with the sanded reformulated joint-compound. Two groups of Wistar rats were exposed to either 7RF3 chrysotile (Group 2) or to 7RF3 chrysotile combined with aerosolized sanded joint-compound (Group 3). In addition, a control group was exposed to filtered-air. The chrysotile used in the Ready Mix joint compound is rapidly removed from the lung. The chrysotile alone exposure group had a clearance half-time of fibers L > 20 microm of 2.2 days; in the chrysotile plus sanded exposure group the clearance half-time of fibers L > 20 microm was 2.8 days. However, across all size ranges there was approximately an order of magnitude decrease in the mean number of fibers remaining in the lungs of Group 3 as compared to Group 2 despite similiar aerosol exposures. Histopathological examination showed that the chrysotile exposed lungs had the same appearance as the filtered-air controls. This study uniquely illustrates that additional concurrent exposure to an aerosol of the sanded joint-compound, with large numbers of fine-particles depositing in the lungs, accelerates the recruitment of macrophages, resulting in a tenfold decrease in the number of fibers remaining in the lung. The increased number of macrophages in the chrysotile/sanded joint exposure group was confirmed histologically, with this being the only exposure-related histological finding reported.

Diesel exhaust inhalation increases thrombus formation in man

AIMS

Although the mechanism is unclear, exposure to traffic-derived air pollution is a trigger for acute myocardial infarction (MI). The aim of this study is to investigate the effect of diesel exhaust inhalation on platelet activation and thrombus formation in men.

METHODS AND RESULTS

In a double-blind randomized crossover study, 20 healthy volunteers were exposed to dilute diesel exhaust (350 microg/m(3)) and filtered air. Thrombus formation, coagulation, platelet activation, and inflammatory markers were measured at 2 and 6 h following exposure. Thrombus formation was measured using the Badimon ex vivo perfusion chamber. Platelet activation was assessed by flow cytometry. Compared with filtered air, diesel exhaust inhalation increased thrombus formation under low- and high-shear conditions by 24% [change in thrombus area 2229 microm(2), 95% confidence interval (CI) 1143-3315 microm(2), P = 0.0002] and 19% (change in thrombus area 2451 microm(2), 95% CI 1190-3712 microm(2), P = 0.0005), respectively. This increased thrombogenicity was seen at 2 and 6 h, using two different diesel engines and fuels. Diesel exhaust also increased platelet-neutrophil and platelet-monocyte aggregates by 52% (absolute change 6%, 95% CI 2-10%, P = 0.01) and 30% (absolute change 3%, 95% CI 0.2-7%, P = 0.03), respectively, at 2 h following exposure compared with filtered air.

CONCLUSION

Inhalation of diesel exhaust increases ex vivo thrombus formation and causes in vivo platelet activation in man. These findings provide a potential mechanism linking exposure to combustion-derived air pollution with the triggering of acute MI.