Jonathan Bury

MLH1 −93G>A promoter polymorphism and risk of mismatch repair deficient colorectal cancer

Rare inherited mutations in the mutL homolog 1 (MLH1) DNA mismatch repair gene can confer an increased susceptibility to colorectal cancer (CRC) with high penetrance where disease frequently develops in the proximal colon. The core promoter of MLH1 contains a common single nucleotide polymorphism (SNP) (−93G>A, dbSNP ID:rs1800734) located in a region essential for maximum transcriptional activity. We used logistic regression analysis to examine the association between this variant and risk of CRC in patients in the United Kingdom. All statistical tests were 2 sided. In an analysis of 1,518 patients with CRC, homozygosity for the MLH1 −93A variant was associated with a significantly increased 3‐fold risk of CRC negative for MLH1 protein by immunohistochemistry (odds ratio (OR): AA vs GG = 3.30, 95% CI 1.46–7.47, n = 1392, p = 0.004, MLH1 negative vs MLH1 positive CRC) and with a 68% excess of proximal CRC (OR: AA vs GG=1.68, 95% confidence interval (CI) 1.00–2.83, n = 1,518, p = 0.05, proximal vs distal CRC). These findings suggest that the MLH1 −93G>A polymorphism defines a low penetrance risk allele for CRC.

The correlation between the grade of dyskaryosis on cervical smear, grade of cervical intraepithelial neoplasia (CIN) on punch biopsy and the final histological diagnosis on cone biopsies of the cervix

HEATLEY M. K. AND BURY J. P. (1998) Cytopathology9, 93–99

A study protocol to investigate the relationship between dietary fibre intake and fermentation, colon cell turnover, global protein acetylation and early carcinogenesis: the FACT study.

BackgroundA number of studies, notably EPIC, have shown a descrease in colorectal cancer risk associated with increased fibre consumption. Whilst the underlying mechanisms are likely to be multifactorial, production of the short-chain fatty-acid butyrate fro butyratye is frequently cited as a major potential contributor to the effect. Butyrate inhibits histone deacetylases, which work on a wide range of proteins over and above histones. We therefore hypothesized that alterations in the acetylated proteome may be associated with a cancer risk phenotype in the colorectal mucosa, and that such alterations are candidate biomarkers for effectiveness of fibre interventions in cancer prevention.Methods an designThere are two principal arms to this study: (i) a cross-sectional study (FACT OBS) of 90 subjects recruited from gastroenterology clinics and; (ii) an intervention trial in 40 subjects with an 8 week high fibre intervention. In both studies the principal goal is to investigate a link between fibre intake, SCFA production and global protein acetylation. The primary measure is level of faecal butyrate, which it is hoped will be elevated by moving subjects to a high fibre diet. Fibre intakes will be estimated in the cross-sectional group using the EPIC Food Frequency Questionnaire. Subsidiary measures of the effect of butyrate on colon mucosal function and pre-cancerous phenotype will include measures of apoptosis, apoptotic regulators cell cycle and cell division.DiscussionThis study will provide a new level of mechanistic data on alterations in the functional proteome in response to the colon microenvironment which may underwrite the observed cancer preventive effect of fibre. The study may yield novel candidate biomarkers of fibre fermentation and colon mucosal function.Trial RegistrationTrial Registration Number: ISRCTN90852168

LISA: a web‐based decision‐support system for trial management of childhood acute lymphoblastic leukaemia

Continuation chemotherapy is a key component of the treatment of childhood acute lymphoblastic leukaemia. During this treatment phase, weekly dose adjustments are carried out based on current and historical full blood counts (FBCs). The dose decision pathway is complex and suboptimal therapy may result if information on FBC results is not readily available and/or the prescriber is inexperienced. A web‐based decision‐support system (Leukaemia Intervention Scheduling and Advice, ‘LISA’) was designed to facilitate access to FBC information across geographical locations and to assist with dosage adjustments. A balanced‐block crossover analysis was performed to evaluate the system. Thirty‐six clinicians with varying degrees of experience were each asked to decide on appropriate oral chemotherapy dosages for eight simulated cases: four using LISA and four without. LISA significantly reduced the number of erroneous prescriptions (zero of 144 with LISA vs. 54 of 144 without; P < 0·0001) without affecting the number of times subjects deliberately overrode the protocol (seven of 144 times using LISA and six of 144 without). Using LISA reduced the time taken by novices to reach a decision for each case but increased the time taken by experts. Thirty‐five of 36 subjects said they would be likely to use the system if it were available. A system like LISA is likely to be acceptable to clinicians, and has the potential to increase protocol compliance and decrease prescribing errors while allowing clinicians to override the protocol in specific cases where sound reasons exist for doing so.

Image analysis of low magnification images of fine needle aspirates of the breast produces useful discrimination between benign and malignant cases.

Image analysis of low magnification images of fine needle aspirates of the breast produces useful discrimination between benign and malignant cases

Commonly used bowel preparations have significant and different effects upon cell proliferation in the colon: a pilot study.

BackgroundMarkers of crypt cell proliferation are frequently employed in studies of the impact of genetic and exogenous factors on human colonic physiology. Human studies often rely on the assessment of tissue acquired at endoscopy. Modulation of cell proliferation by bowel preparation with oral laxatives may confound the findings of such studies, but there is little data on the impact of commonly used bowel preparations on markers of cell proliferation.MethodsCrypt length, crypt cellularity and crypt cell proliferation were assessed in biopsies acquired after preparation with either Klean-Prep or Picolax. Crypt cell proliferation was assessed by whole-mount mitotic figure count, and by two different immunohistochemical (IHC) labelling methods (Ki-67 and pHH3). Subsequent biopsies were obtained from the same patients without bowel preparation and similarly assessed. Parameters were compared between groups using analysis of variance and paired t-tests.ResultsThere were significant differences in labelling indices (LI) between biopsies taken after Klean-prep and those taken after Picolax preparation, for both Ki67 (p = 0.019) and pHH3 (p = 0.017). A similar trend was seen for whole-mount mitotic figure counts. Suppression or elevation of proliferation parameters by bowel preparation may mask any effect due to an intervention or disease.ConclusionCommonly used bowel preparations may have significant and different effects on crypt cell proliferation. This should be taken into account when designing studies and when considering the findings of existing studies.

Keratin 8 expression in colon cancer associates with low faecal butyrate levels

BackgroundButyrate has been implicated in the mechanistic basis of the prevention of colorectal cancer by dietary fibre. Numerous in vitro studies have shown that butyrate regulates cell cycle and cell death. More recently we have shown that butyrate also regulates the integrity of the intermediate filament (IF) cytoskeleton in vitro. These and other data suggest a link between the role of diet and the implication of a central role for the keratin 8 (K8) as guardian of the colorectal epithelium.MethodsIn this cross-sectional study possible links between butyrate levels, field effects and keratin expression in cancer were addressed directly by analysing how levels of expression of the IF protein K8 in tumours, in adjacent fields and at a distant landmark site may be affected by the level of butyrate in the colon microenvironment. An immunohistochemical scoring protocol for K8 was developed and applied to samples, findings were further tested by immunoblotting.ResultsLevels of K8 in colorectal tumours are lower in subjects with higher levels of faecal butyrate. Immunoblotting supported this finding.Although there were no significant relationships with butyrate on the non-tumour tissues, there was a consistent trend in all measures of extent or intensity of staining towards a reduction in expression with elevated butyrate, consistent with the inverse association in tumours.ConclusionsThe data suggest that butyrate may associate with down-regulation of the expression of K8 in the cancerized colon. If further validated these findings may suggest the chemopreventive value of butyrate is limited to early stage carcinogenesis as low K8 expression is associated with a poor prognosis.

Evaluating the reliability of causes of death in published clinical research

Deaths during clinical trials or outcome review studies could be due to the disease being studied; adverse complications of interventions in the study; intercurrent disease unrelated to the initial condition or interventions; or unnatural events. Accurate ascertainment of the causes of deaths is therefore required to establish whether treatment has prevented deaths from the investigated disease without concomitant increases in death or morbidity from other causes. We assessed the methods used to evaluate causes of death in published clinical research. All 879 papers published in 1994 in the Lancet , BMJ , Annals of Internal Medicine , and New England Journal of Medicine were reviewed; the methods used to evaluate the causes of death in each paper were recorded using 11 categories (table 1). Death was an outcome measure in 223 papers (25%). …

Identification of key residues involved in mediating the in vivo anti-tumor/anti-endothelial activity of Alphastatin.

Summary.  Background : We have recently shown that Alphastatin, a 24‐amino‐acid peptide (ADSGEGDFLAEGGGVRGPRVVERH) derived from human fibrinogen has anti‐endothelial properties in vitro and in vivo.

Computerised Advice on Drug Dosage Decisions in Childhood Leukaemia: A Method and a Safety Strategy

Currently over 95% of children who are diagnosed with Acute Lymphoblastic Leukaemia in the UK are enrolled into Medical Research Council trials. The trial protocol specifies that following initial treatment there is a 2-3 year maintenance period during which drug dosage decisions are made weekly according to a set of pre-defined rules. These rules are complex, and there is a significant frequency of error in clinical practice, which can lead to patient harm. We have built a web-based decision support system (called LISA) to address this problem. The dose alteration rules from the MRC protocol were formalised in the PROforma guideline modeling language as a state transition problem, and dose adjustment recommendations are provided into the clinical setting by a PROforma enactment engine. The design and implementation of the decision support module, the safety issues raised and the strategy adopted for resolving them are discussed. System safety is very likely to become a major professional challenge for the medical AI community and it can be addressed, in this case, with relatively straightforward techniques.