Acid sensing ion channels, ASICs, are a family of ligand-gated cation channels, activated by acid (pH 7.4 — 5.5), which belong to the amiloride-sensitive degenerin/epithelial Na+ channel (ENaC) superfamily. Stimulation of these receptors on nerves leads to a variety of sensations including pain and mechanoperception, while epithelial expression linked to airway secretion has been reported in cystic fibrosis cell lines. A description and function of these receptors in human upper airways has not been described.

Our aim was to determine if the acid-sensing ion channel receptors, specifically type 3 (ASIC-3), are present, upregulated, and functional, in the nasal mucosa of patients with allergic rhinitis, and if they play a role in the allergic rhinitis constituent symptom of rhinorrhoea.

Eosinophils are almost always found in the mucosa, the submucosa and in the nasal secretions of subjects with allergic rhinitis. We hypothesised that the eosinophil has a major role to play in inflammatory conditions such as allergic rhinitis, and may have a role in acting via ASIC receptors, inducing them, or mediating them to react.

Our findings, as shown through real time polymerase chain reaction quantification of ASIC receptors in nasal biopsies, demonstrated no mRNA for ASIC-1 or ASIC-2. ASIC-3 was seen in both healthy controls and allergic rhinitis, in whom it was significantly increased (p

Functional experiments with lactic acid (pH 7.0) demonstrated significantly increased nasal secretary responses on the ipsilateral but not contralateral side, which were blocked by amiloride (ImM).

Eosinophils and released major basic protein (MBP) were found in association with airway nerve cells, mucous glands and epithelial cells. Eosinophil granule proteins increased the expression of ASIC-3 and showed a significant upregulation of ASIC-3 in an ERK-kinase dependent manner.

Thus, functional ASIC-3 receptors are present in nasal mucosa, and their expression is upregulated in allergic rhinitis via released eosinophil granule proteins. This data indicate a link with tissue inflammation, which may lead to enhanced nasal secretion in allergic rhinitis.

This study tested the hypothesis that endothelial progenitor cell (EPC) pathology provides a unifying explanation for the tendency to carry low birthweight babies and subsequent increased maternal cardiovascular risk.

Methods:

We measured maternal EPC number and function, conventional cardiovascular risk markers, and cord blood adiponectin in 23 small for gestational age (SGA; birthweightcentile) and 23 appropriate for gestational age (AGA; birthweight >10th centile) pregnancies.

Results:

Median EPC count was lower (294 vs. 367, p=0.005), and EPC migratory capability was reduced (migration index 0.91 vs. 1.59, p

Conclusions:

Giving birth to a SGA infant was associated with lower maternal EPC number and reduced migratory function in vitro. EPC pathology may explain both uteroplacental insufficiency, leading to low birthweight, and future cardiovascular disease in the mother. SGA infants had lower cord blood adiponectin, potentially representing a mechanism for future cardiovascular disease in later life of the infant.

In our first study we aimed to investigate the prevalence of bile reflux in three patient populations; symptomatic controls, Barrett's patients and patients post oesophago-gastric resection for carcinoma. Augmentation of bile reflux was noted in patients who had previous history of cholecystectomy. A high proportion of patients remained symptomatic post-cholecystectomy and a high proportion of these still-symptomatic post-cholecystectomy patients had increased bile reflux index.

In our second retrospective study we examined the effects of cholecystectomy on gastric and oesophageal mucosa at molecular and histological level. There was an increase in bile reflux index, Ki67 and p53 in post-cholecystectomy patients. This raised concern about development of pre-malignant changes in these patients.

In the third study, the effect of cholecystectomy on gastric and oesophageal microenvironment was evaluated prospectively. This study noted the histological and molecular changes precipitated by cholecystectomy are similar to those identified as precursors of Barrett's oesophagus. Such concerning changes suggest that options other than cholecystectomy be considered for patients with gallstones in a functioning gallbladder.

Surgical patients are particularly at risk of healthcare associated infection (H C A I) by virtue of the presence of a surgical site leading to surgical site infections (S S I) and because of the need for intravascular access resulting in catheter-related bloodstream infection (C R B S I).

Methods

A two-year initiative commenced with an initial audit of surgical practice which was used to inform the development of a targeted educational initiative by surgeons specific for surgical trainees. Parameters assessed during initial and repeat audits after the educational initiative included intra- and post-operative aspects of the prevention o f S S I as well as the care of peripheral venous cannulae (P V C ) in surgical patients.

Results

The proportion of prophylactic antibiotics administered pre-incision across 360 operations increased from 30% to 59.1% (p

Conclusion

Significant improvements were seen in surgical practice in S S I and C R B S I prevention through a focused educational programme developed by and for surgeons.

Simulation-trained trainees scored higher than the controls on the procedural checklist developed (86.80 ± 5.36 vs. 67.60 ± 6.02 P = 0.001) and a global rating scale (37.20 ± 4.09 vs. 24.40 ± 5.32 P = 0.003) when performing SFA angioplasty on patients. Similarly, bench model simulation-trained trainees scored higher than the controls on procedural (30.33 ± 2.07 vs. 18 ± 2.19 P < 0.001) and global (28.33 ± 1.86 vs. 18.50 ± 4.04 P < 0.001) rating scales when performing SFJ dissection on patients. Basic surgical skills acquired using proficiency-based simulation training in SFA angioplasty and SFJ dissection do translate to real world performance. Structured proficiency-based simulation training in SFA angioplasty and SFJ dissection should be incorporated into surgical training programs.

Breast cancer is the most commonly diagnosed malignancy in women in Ireland after non-melanoma skin cancer, with over 2,000 women diagnosed with the disease each year. It remains the leading cause of cancer-related mortalities in women, with an average annual rate of 644 deaths between 1994 and 2001. Although the mortality rate decreased between 1989 and 2006 by nearly 27%, it still remains one of the highest mortality rates in Europe. Targeted therapy against the key receptors identified to date as being integral to the development and proliferation of breast cancers has significantly improved the overall and disease-free survival rates for patients. However, innate and acquired resistance to these therapeutic agents, including tamoxifen and trastuzumab, results in tumour recurrence which is not susceptible to further standard therapeutic interventions. Resistance to tamoxifen can occur in up to one quarter of patients after ten years, while the majority of patients with metastatic disease will develop resistance to trastuzumab within one year of treatment.

Resistance to tamoxifen is thought to occur through a number of proposed mechanisms. One such proposal is the concept of crosstalk between ER and the growth factor receptor pathways including the EGFR/HER2 family of receptors. This can result in resistance developing through a number of different mechanisms including Src kinase activation of the metalloproteinases with resultant activation of the MAPK pathway as well as Akt upregulation through PI3K and ras activation of ERK1 and ERK2.

While extensive in vitro research has been performed to determine how resistance to trastuzumab develops, the exact mechanisms remain inconclusive. Hypotheses include alteration in the interaction between the receptor and the antibody, alternative signalling through other HER or alternate pathways or failure to activate immune-mediated mechanisms to destroy tumour cells. Understanding how resistance to trastuzumab develops would greatly improve the clinical prognosis for patients with HER2 expressing breast cancers, as it would enable clinicians to identify patients at risk of developing resistance and facilitate the tailoring of specific treatments to minimise the risk of such an outcome occurring.

Hypothesis

Research has highlighted the complex interactions that occur at a molecular level within breast cancer cells. Receptor crosstalk has been implicated in the development of resistance to endocrine therapies such as tamoxifen. We hypothesise that resistance to trastuzumab can be mediated by crosstalk between the growth factor signalling pathway and the steroid hormone pathway resulting in an uncontrolled upregulation of the steroid hormone pathway following trastuzumab treatment.

Aims

The overall aim of this work is to further elucidate the interactions between the steroid hormone and growth factor signalling pathways in breast cancer, in particular, to determine the effect of trastuzumab treatment on the steroid hormone pathway. The first objective will be to assess the effect of trastuzumab treatment on this pathway at a molecular level in breast cancer cells, looking at its effect at both a protein level and a transcriptional level. Secondly, we will verify our in vitro findings in breast cancer tissue samples utilising a large tissue microarray, assessing the clinical significance of our proposed crosstalk hypothesis.

Results

Protein expression levels of ER within the oestrogen sensitive MCF-7 cells was found to be increased following trastuzumab treatment while there was no effect observed in the oestrogen insensitive LCC-1 cells. Surprisingly, treatment of ERnegative SKBR-3 cells with trastuzumab resulted in the expression of ER. Luciferase assay and RT-PCR was performed to assess whether trastuzumab had an enhancing effect on the functional activity of the steroid hormone pathway within the cell model. pS2, a well established ER target gene, was utilised to demonstrate activity. Increased levels of pS2 was observed following trastuzumab treatment in both the MCF-7 and SKBR-3 cell lines, with no difference in the LCC-1 cells.

Methylation studies were performed to determine whether they played a role in the expression of ER within the ER-negative SKBR-3 cells following trastuzumab treatment. Treatment was found to result in the demethylation of five CpG islands within the promoter region of the ER gene within the cells, thereby demonstrating that trastuzumab can result in epigenetic modifications in certain ER-negative cells resulting in the potential expression of a functional ER.

Immunohistochemistry staining for pS2 of a tissue microarray of almost five hundred breast cancer specimens was performed. Survival analysis of HER2 positive patients who expressed pS2 showed that patients had a significantly increased rate of recurrence if they received trastuzumab compared to those who did not. Similarly, a small cohort of patients who received trastuzumab prior to surgical resection were found to have significantly stronger staining for pS2 in their post-trastuzumab treated specimens when compared to their pre-treatment biopsies.

Conclusion

Resistance to trastuzumab remains a significant factor in the development of tumour recurrence in HER2-expressing breast cancers, resulting in reduced overall and disease-free survival times. To date, the exact mechanism by which resistance can develop remains elusive. In this work, molecular studies have demonstrated crosstalk between the steroid hormone and growth factor receptor pathways, suggesting that resistance can develop through upregulation of the endocrine signalling pathway. Furthermore, trastuzumab was also found to result in the expression of a functional ER in ER-negative cells, providing a previously unconsidered potential therapeutic target for these cancers. Translational studies confirmed that the in vitro findings were replicable within a clinical cohort, affecting patient prognosis.

These findings constitute a minute fragment of the complex interactions between the steroid hormone and growth factor receptor pathways in breast cancer. The plasticity of breast cancer and its ability to overcome therapeutic interventions through receptor crosstalk as well as its capacity to alter receptor status demonstrates the complex molecular mechanisms involved in the disease process. Resistance to therapies is likely to present a significant challenge to both clinicians and academics for many years to come. However, translational research methods, as demonstrated within this body of work are essential to unravel our understanding of this complex disease.

Aim: The overall objective of this thesis was to investigate and evaluate those factors that could influence the length of the learning curve and the capacity of a trainee to become a proficient minimally invasive surgeon.

Materials & Methods: We evaluated three different areas; psychometric aptitude (visual spatial, depth perception & psychomotor), personality traits and non-technical skills (musical ability, playing sport & video games) and how these factors impacted on the surgical novice, junior and senior trainees ability to perform in both basic minimally invasive skills (laparoscopy, endoscopy & endovascular) and more advanced skills (laparoscopic colectomy) in a simulated setting.

Results: The results demonstrated that there is a relationship between psychometric aptitude and MIS performance. This association was greatest in frequency and most consistent amongst the surgical novices with its effect decreasing with increasing surgical experience. However, the results also demonstrated that in trainees with significant surgical experience psychometric aptitude was associated with performance in an advanced MIS task (laparoscopic colectomy). Certain personality traits were also found to be associated with MIS performance (distractibility, confidence & energy). Finally, musical ability in particular was found to have the greatest association with MIS performance in contrast to the other nontechnical skills measured.

Conclusion: We have shown that certain attributes influence the learning curve and the fundamental ability of the trainee surgeon in MIS techniques. These findings have relevance in the design of training curricula and when ensuring the optimum learning pathway for the individual trainee.

Dementia is a progressive and largely irreversible clinical syndrome which is characterised by a disturbance of higher cortical functioning, occurring in clear consciousness. Alzheimer’s disease is the most common form of dementia. People with Down’s syndrome, the most common genetic cause for intellectual disability, have a significantly increased risk for developing Alzheimer’s disease in later life.

Neuroimaging is an important tool in the preclinical detection and monitoring of Alzheimer’s disease. Much attention has focused on volumetric manual Region of Interest MRI studies to investigate changes confined to a limited set of brain regions. Automatic techniques have been developed to study more widespread brain volume and thickness measures than Region of Interest MRI studies. Proton Magnetic Resonance Spectroscopy (HI-MRS) can be employed to investigate the concentrations of a number of brain metabolites including N-acetylaspartate [NAA], myo-inositol [ml], choline [cho] and creatine plus phosphocreatine [Cr+PCr], NAA is hypothesized to be a marker of the number of viable neurons. Elevation of ml is a marker for gliosis.

To my knowledge, no in vivo case-control study exists comparing the anatomy of dementia in Down’s syndrome to people with Alzheimer’s disease in the general population.

Methodology

Subjects were scanned using a 1.5 Tesla, GE NU/i Signa MR System at the Maudsley Hospital in London. The reformatted SPGR data set was analysed using Measure Software. Volumetric analysis of the hippocampi, temporal lobes, lateral ventricles, whole brain and total cranial volumes were performed by means of manually tracing regions of interest to compare subjects with Down’s syndrome to those with Alzheimer’s disease in the general population. In addition, an automated technique enabled the investigation of more widespread brain volume and thickness measures in subjects with Down’s syndrome, Alzheimer’s disease and age-matched healthy controls. Additional volumetric analysis was undertaken on MRI scans of subjects with Alzheimer’s disease, mild cognitive impairment and Alzheimer’s disease healthy controls at baseline and on subjects who were re-scanned after 12 months. Magnetic resonance spectroscopy was used to investigate differences in hippocampal metabolite concentrations between subjects with Down’s syndrome, Alzheimer’s disease and age-matched healthy controls.

Results

Subjects with dementia had a significant reduction in the volume of the hippocampus, temporal lobe and whole brain and an increase in the volume of the lateral ventricles, compared to their non-demented controls. There was a significant correlation between atrophy of the hippocampus and temporal lobe, and cognitive decline. Significant differences were demonstrated for more global cortical volume and thickness measures between demented and non-demented subjects, and between subjects with Alzheimer’s disease and demented subjects with Down’s syndrome.

In the longitudinal study, when compared to age matched healthy controls, subjects with Alzheimer’s disease had a significant reduction in the volume of the hippocampus and temporal lobe, and an increase in the volume of the lateral ventricles at baseline and when re-scanned at 12 months, and subjects with mild cognitive impairment had findings intermediate between those of Alzheimer’s disease and age matched healthy controls. The Alzheimer’s disease group had a significant reduction in [NAA] compared to its age matched healthy control group but not when compared to demented subjects with Down’s syndrome or younger Down’s syndrome healthy control groups. Demented subjects with Down’s syndrome had a significantly higher [ml] than the other groups.

Conclusion

MRI and HI-MRS are useful tools to compare the anatomy of dementia in Down’s syndrome to subjects with Alzheimer’s disease in the general population. Significant differences between demented and non-demented subjects can enable the distinction between subjects with and without dementia, and may distinguish between individuals with Alzheimer’s disease and demented subjects with Down’s syndrome.

Recent advances in understanding the pathophysiology of the consequences of fibrillin-1 deficiency in Marfan syndrome and the development of murine models of this condition have opened up the possibility for translational research to be conducted in this area. Potential pharmacological treatments can now be extensively researched prior to clinical trials.

Pravastatin, a 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibitor has been shown to have a beneficial effect on atherosclerosis via “pleiotropic,” or noncholesterol related, anti-inflammatory mechanisms. These mechanisms may have a beneficial effect in aortic root pathology in Marfan syndrome.

The first aim of this research was to establish a natural history of aortic root pathology in Marfan syndrome and to study multiple aspects of aortic root pathology to gain an insight into the pathophysiology of the disease. The second aim was to compare the efficacy and mechanism of potential pharmacological treatments to attenuate aortic root pathology in Marfan syndrome, Pravastatin, Losartan and Doxycycline. The third aim was to optimise the dose and timing of administration of Pravastatin for aortic root pathology in Marfan syndrome. These aims were studied in a murine model of Marfan syndrome.

The results obtained demonstrate that Pravastatin is equipotent to Losartan in attenuation of aortic root dilatation in a murine model of Marfan syndrome. Doxycycline’s performance was inferior to both Pravastatin and Losartan in attenuation of aortic root pathology.

This research provides a basis for further study into the mechanisms of aortic pathology. It also provides evidence for a novel potential treatment for aortic root pathology in Marfan syndrome, namely, Pravastatin.

Transoesophageal echocardiographic (TOE)-defined mobile, thread-like valvular strands (VS) have been associated with acute ischaemic stroke (AIS). The relationship between VS as a possible embolic substrate and the risk of recurrent stroke remains unclear. Our primary aims were to measure the prevalence of VS and explore their association with AIS in a case-control study and then, compare the risk of subsequent poor vascular outcome (vascular events and vascular death) in the stroke cohort patients with or without VS in a follow-up study. Our secondary aims were to determine the relationship of VS to other potential cardiac sources of emboli in TOE, relationship of VS to diastolic dysfunction in stroke cohort on comparison with controls. In addition, we sought to evaluate the relationship of VS to ischaemic stroke subtype and infarct topography on neuroimaging, and also to determine the relationship of hypercoagulable states in young patients with VS in the stroke cohort.

Methods:

In the case-control study, the prevalence of VS was estimated from patients consecutively admitted with AIS and from patients underwent TOE for cardiac conditions (those with infective endocarditis and stroke were excluded) in our institution over a two year period. In the follow-up study, patients with AIS were followed to evaluate the risk of poor vascular outcome, including risk of recurrent stroke.

Results:

We recruited 170 patients with AIS and of those, 78 underwent TOE. In our case-control study, we found TOE-defmed VS in approximately half of the patients with AIS (38/78, 48.7%) compared to one-third of controls (29/89, 32.6%). VS were more commonly seen in stroke patients over the age of 60 years (21/34, 61.8%). Univariate analysis found an association between the presence of VS and risk of AIS (OR = 3.85 ,p = 0.05), but multivariate analysis reduced the strength of the association (OR = 2.15,p= 0.06). In stroke subtypes, high prevalence of VS was seen in cardioembolic stroke but it did not reach statistical significance (p = 0.52) and there was no increased frequency of VS in cryptogenic stroke subtype. Diastolic dysfunction was seen in 78.9 % of cases with VS and there was a strong association between diastolic dysfunction and VS in the case-control study (OR 7.75,/) = 0.005). There was no statistically significant association between infarct location (cortical, subcortical, brainstem or cerebellar) in neuroimaging and the presence of VS. There were only few young cases with abnormalities in laboratory testing for hypercoagulable conditions. The risk of recurrent stroke and survival without poor vascular outcome was not statistically different between cases with or without VS in our study (OR = 1.45, 95 % Cl 0.30 - 6.96,p = 0.64).

Conclusion:

We were able to demonstrate an association between valvular strands and acute ischaemic stroke in our case-control study, however, the strength of the association was reduced after multivariate analysis. We did not find any increased risk of poor vascular outcome or increased recurrent stroke risk in cases with or without VS. Our findings do not support the embolic potential of valvular strands and it may not be a risk factor for stroke.

The standardised mortality ratio for craniopharyngioma patients in this study was 8.75, with a predominance of deaths due to cardiovascular andrespiratory disease. Over 80% of CP patients had panhypopituitarism, including diabetes insipidus. Four patients with diabetes insipidus had adipsia, which is associated in the published literature with increased morbidity and mortality. Tumour recurrence ocurred in 46%, and hydrocephalus was diagnosed in 40% of CPs. Sixty-six percent of CPs were obese and 26% were overweight.

Seventy-one percent of CP patients suffered from somnolence and 46%were diagnosed with sleep apnoea; thus not all somnolence in CP wasexplained by sleep apnoea. Somnolence responded to treatment with continuous positive airway pressure therapy or modafinil.

Abnormal glucose tolerance was identified in 40% of CP patients, who were insulin resistant and obese or overweight. The CP patients with abnormal glucose tolerance were older when diagnosed with CP than those with normal glucose tolerance.

CP patients had similar ghrelin levels to normal weight controls, which suggested that excess ghrelin was not the explanation for obesity in CP. However serum ghrelin levels in CP patients suppressed after food ingestion and were lower in patients with apnoea than in those without apnoea, which suggested that the hypothalamus remained sensitive to ghrelin signalling.

This study confirms the previous reports of high rates of morbidity and mortality in CP patients and identifies new targets for treatment of morbidity, such as dysnatraemia, somnolence and abnormal glucose tolerance.

We demonstrated a significant further derangement in protease anti-protease balance in those with chronic infection compared to all others with CF, with higher free neutrophil elastase and cathepsin levels, and lower levels of SLPI and elafin. Neutrophil elastase levels correlated very clearly with lung function. The chronically infected group also showed a shift towards a Th2 cytokine response in BAL with elevated levels of IL-4, reduced levels of IFN- y and an increased IL-4: IFN-y ratio compared to other CF groups. We demonstrated a significant reduction in levels of both IL-6 and MCP-1 in the chronically infected group, which may be related to degradation by airway proteases. We showed that Vitamin D and it's analogues can act to reduce pro-inflammatory cytokine release from stimulated respiratory epithelial cells in CF through an inhibition of IkBɑ.Vitamin D levels were lower in children with chronic P. aeruginosa infection compared to other groups but were not linked to differences in lung function or inflammation. We demonstrated evidence of pulmonary aspiration in a subset of children with CF by finding elevated pepsin levels in BAL,, and showed that the levels of pepsin were closely correlated to IL-8 levels.

This thesis sheds new light on the pulmonary innate defence system in children with CF at various stages of P. aeruginosa infection and confirms the beneficial and deleterious effects respectively of vitamin D and pulmonary aspiration on inflammation in the CF lung.

Autoantibodies against neutrophil granule proteins such as proteinase 3 (PR3) and neutrophil elastase (NE) have been linked with patients with Z-AlATD. Here we show that antibodies against primary neutrophil granule proteins (PR3 and NE) as well as secondary neutrophil granule proteins (lactoferrin) are present in plasma of patients with Z-A1 ATD.

In conclusion, this study highlights that anti-elastin antibodies are tissue specific and are detected in the BALF of COPD and Z-AlATD despite the absence of these autoantibodies in the plasma. The low level of BALF anti-elastin antibodies in CF may have a protective role. It also highlights the potential role of therapeutic agents targeting these autoantibodies in the lungs. Lastly, neutrophil granule proteins are important antimicrobials and autoantibodies against primary (PR3 and NE) as well as secondary neutmphil granule proteins (lactoferrin) are detected in patients with ZAlATD in this study. Similarly, there may be a potential role of therapeutic agents targeting these autoantibodies.

This population study examines the prevalence of psychiatric morbidity, behavioural difficulties, autistic and schizotypal features in a sample of individuals with 22q11.2DS and in their sibling controls.

Methods:

Forty-five individuals with 22q11.2DS and their 27 siblings were recruited and studied. Psychiatric morbidity was assessed by using the parent Diagnostic Interview Schedule for Children (DISC-P), Kiddie SADS-Present and Lifetime Version (K-SADPL) (psychotic supplement), Comprehensive Assessment of the At Risk Mental State (CAARMS), Schedule for Clinical Assessment in Neuropsychiatry (SCAN) and the parent Conners' rating scale. Behavioural difficulties were measured by the Strengths and Difficulties Questionnaire (SDQ) and the Child Behaviour Checklist (CBCL). The Social Responsiveness Scale (SRS) and the Social Communication Questionnaire (SCQ) were used to measure symptoms of autism. The Schizotypal Personality Questionnaire (SPQ) was used to measure for schizotypal features.

Results:

Children and adolescents with 22q11.2DS were found to have more internalising and externalising behaviour compared to their siblings; 25% of children and adolescents with 22q11.2DS had social problems within the clinical range. Individuals with (see Figure 1,2,3,4,5 & 6)

The first part of this study aimed to update and reanalyse the Irish MND population data. In particular it was of interest to compare current incidence and prevalence data from a study published in 1999 to examine for changing population trends after introduction of new standards of care in nutritional and respiratory management of MND. In addition we extended advice and support to the NI MND services in the establishment of a sister register in NI such that 'all Ireland' MND population data could be calculated, this is part of an MD thesis by Dr Colette Donaghy in NI. We discovered relatively stable epidemiology in our MND population over the last decade with identical figures produced by the NI MND register. It would appear that new standards of care have not yet impacted life expectancy in the Irish MND population but further study is required in the future.

Age, male gender, family history and smoking are the only known risk factors (RFs) for MND to date. Identifying potential RF for MND may allow avoidance of high risk activities in those with other predisposing factors. Athleticism or a history of heavy physical activity is a controversial putative RF for MND. We conducted a prospective case control study to evaluate this hypothesis using a validated lifetime historical activity questionnaire. We found that a history of exercise did increase the risk of MND, particularly spinal onset disease and that physical activity conducted at work can contribute significantly to calculated figures and should not be omitted. In addition significant differences in energy expenditure defined as 'vigorous' were noted between MND cases and controls.

Deficiency of insulin-like growth factor (IGF) has been described in MND patients. Whether this is coincidental or a primary or secondary phenomenon in the disease is unclear. Many other factors can influence IGF levels such as starvation and stress. We conducted both cross sectional and longitudinal studies of IGF in our MND cases and compared them to populations with multiple sclerosis (MS), post-polio syndrome (PPS) and normal controls. In addition nutritional and functional indices were evaluated serially and correlated with IGF data. Our data confirmed perturbations in the IGF system in MND and suggested that IGF-1 levels dip pre-agonally in MND patients.

In a study of 199 patients with coronary artery disease, 30 (15%) were aspirin resistant when measured by the Platelet Function Analyser (PFA)-I 00. Non-responsiveness was related to enhanced reactivity to epinephrine (median 38% vs 23%, p < 0.05) and increased inducible platelet activation (median 66% vs 56%, p < 0.05). There was no association between the PIª² genotype and aspirin response.

In another study of the GPllb/Illla antagonist tirofiban in patients (n = 21) presenting with an acute coronary syndrome we found evidence for inadequate inhibition of platelet aggregation in the majority (66%) of patients at standard dose. There was evidence for significant interindividual variation in the antithrombotic response to tirofiban (p < 0.05), however there was poor agreement between the different assays used. No predictors of variability were detected. Consistent with a partial agonist effect, there was enhanced inducible platelet activation during tirofiban treatment (61 % versus 37%, p = 0.004).

In a third study we examined the role of GPllla promoter polymorphisms on platelet fibrinogen receptor (GPllb/Illla) expression in 207 patients with a history of an acute coronary syndrome. The promoter polymorphisms were in tight linkage disequilibrium with the PIª² polymorphism of GPllla, but did not affect GPllb/lllla receptor expression density.

Finally, to determine the effect of PIª² on the antithrombotic response to GPllb/Illla antagonists, we studied an enriched group of individuals with the PIª² genotype (n = 20). We confirmed a partial agonist effect with GPllb/Illla antagonists in vitro manifest as increased platelet P-selectin expression and thromboxane generation. Corrected p-selectin expression was significantly increased in PIª² homozygotes compared to wildtype controls after incubation with orbofiban (24.8% vs 10.1%, p = 0.02).

In conclusion, we detected variability in the response to aspirin and GPllb/Illla antagonists. Aspirin resistance was linked to increased reactivity to epinephrine and increased platelet activation. Variation in the expression of the GPllb/Illla receptor was not related to the PIª² genotype or its associated promoter polymorphisms. However PIª² appears to enhance partial agonism in the presence of small molecule GPllb/Illla antagonists, suggesting an effect of this polymorphism on outside-in signalling by the GPllb/Illla receptor.