Aaron Quyn

Spindle Orientation Bias in Gut Epithelial Stem Cell Compartments Is Lost in Precancerous Tissue

The importance of asymmetric divisions for stem cell function and maintenance is well established in the developing nervous system and the skin; however, its role in gut epithelium and its importance for tumorigenesis is still debated. We demonstrate alignment of mitotic spindles perpendicular to the apical surface specifically in the stem cell compartments of mouse and human intestine and colon. This orientation correlates with the asymmetric retention of label-retaining DNA. Both the preference for perpendicular spindle alignment and asymmetric label retention are lost in precancerous tissue heterozygous for the adenomatous polyposis coli tumor suppressor (Apc). This loss correlates with cell shape changes specifically in the stem cell compartment. Our data suggest that loss of asymmetric division in stem cells might contribute to the oncogenic effect of Apc mutations in gut epithelium.

Photodynamic therapy is associated with an improvement in survival in patients with irresectable hilar cholangiocarcinoma

BACKGROUND The majority of patients with hilar cholangiocarcinoma have irresectable disease and require palliation with biliary stenting to alleviate symptoms and prevent biliary sepsis. Chemotherapy and radiotherapy have proved ineffective, but recent studies suggest photodynamic therapy (PDT) may improve the outlook for these patients. This prospective clinical cohort study has evaluated the efficacy of radical curative surgery, standard palliative therapy (stent +/- chemotherapy) and a novel palliative therapy (stent +/- Photofrin-PDT) in 50 consecutive patients treated for hilar cholangiocarcinoma over a 5-year period. METHODS Between January 2002 and December 2006, 50 patients with hilar cholangiocarcinoma were evaluated for treatment. Ten patients were considered suitable for curative resection (Cohort 1). Forty patients with irresectable disease were stratified into Cohort 2 - Stent +/- chemotherapy (n= 17); and Cohort 3 - Stent +/- PDT (n= 23). Prospective follow-up in all patients and data collected for morbidity, mortality and overall patient survival. RESULTS The median age was 68 years [range 44-83]. Positive cytology/histology was obtained in 28/50 (56%). One death in Cohort 1 occurred at 145 days after surgical resection. No treatment related-deaths occurred in Cohort 2 or 3, chemotherapy-induced morbidity in three patients in cohort 2, PDT-induced morbidity in 11 patients in cohort 3. Actual 1-year survival was 80%, 12% and 75% in Cohorts 1, 2 and 3, respectively. Mean survival after resection was 1278 days (median survival not reached). Mean and median survival was 173 and 169 days, respectively, in Cohort 2; and 512 and 425 days in Cohort 3. Patient survival was significantly longer in cohorts 1 and 3 (P < 0.0001; Log rank test). CONCLUSION This prospective clinical cohort study has demonstrated that radical surgery and palliative Photofrin-PDT are associated with an increased survival in patients with hilar cholangiocarcinoma.

Preparation of wholemount mouse intestine for high-resolution three-dimensional imaging using two-photon microscopy.

Visualizing overall tissue architecture in three dimensions is fundamental for validating and integrating biochemical, cell biological and visual data from less complex systems such as cultured cells. Here, we describe a method to generate high‐resolution three‐dimensional image data of intact mouse gut tissue. Regions of highest interest lie between 50 and 200 μm within this tissue. The quality and usefulness of three‐dimensional image data of tissue with such depth is limited owing to problems associated with scattered light, photobleaching and spherical aberration. Furthermore, the highest‐quality oil‐immersion lenses are designed to work at a maximum distance of ≤10–15 μm into the sample, further compounding the ability to image at high‐resolution deep within tissue. We show that manipulating the refractive index of the mounting media and decreasing sample opacity greatly improves image quality such that the limiting factor for a standard, inverted multi‐photon microscope is determined by the working distance of the objective as opposed to detectable fluorescence. This method negates the need for mechanical sectioning of tissue and enables the routine generation of high‐quality, quantitative image data that can significantly advance our understanding of tissue architecture and physiology.

Prognostic and therapeutic implications of Apc mutations in colorectal cancer.

The adenomatous polyposis coli gene (Apc) is mutated in most colorectal cancers. The multifunctional character of the Apc protein in the regulation of beta-catenin-mediated gene transcription and cytoskeletal proteins has been well described. An important question is how this protein affects the behaviour of cells within a tumour and how its mutational status influences the prognosis for these tumours. Here we provide an overview of the functions of Apc and examine how this information can be used in the prognosis and development of directed therapy in colorectal cancer.

Application of NICE guideline NG12 to the initial assessment of patients with lower gastrointestinal symptoms: not FIT for purpose?

Background The National Institute for Health and Care Excellence (NICE) published NG12 in 2015. The referral criteria for suspected colorectal cancer (CRC) caused controversy, because tests for occult blood in faeces were recommended. Faecal immunochemical tests for haemoglobin (FIT), which estimate faecal haemoglobin concentrations (f-Hb), might more than fulfil the intentions. Our aim was to compare the utility of f-Hb as the initial investigation with the NICE NG12 symptom-based guidelines. Methods Data from three studies were included. Patients had sex, age, symptoms, f-Hb and colonoscopy and histology data recorded. Sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of f-Hb and NG12 were calculated for all significant colorectal disease (SCD: CRC, higher risk adenoma and inflammatory bowel disease). Overall diagnostic accuracy was also estimated by the area under the receiver operating characteristic curve (AUC). Results A total of 1514 patients were included. At a cut-off of ≥10 µg Hb/g faeces, the sensitivity of f-Hb for CRC was 93.3% (95% confidence interval (CI): 80.7–98.3) with NPV of 99.7% (95%CI: 99.2–99.9). The sensitivity and NPV for SCD were 63.2% (95%CI: 56.6–69.4) and 96.0% (95%CI: 91.4–94.4), respectively. The NG12 sensitivity and NPV for SCD were 58.4% (95%CI: 51.8–64.8) and 87.6% (95%CI: 85.0–89.8), respectively. The AUC for CRC was 0.85 (95% CI: 0.87–0.90) for f-Hb versus 0.65 (95%CI: 0.58–0.73) for NG12 (P < 0.005). For SCD, the AUC was 0.73 (95%CI: 0.69–0.77) for f-Hb versus 0.56 (95%CI: 0.52–0.60) for NG12 (P < 0.0005). Conclusion f-Hb provides a good rule-out test for SCD and has significantly higher overall diagnostic accuracy than NG12.

Open versus laparoscopic right hemicolectomy in the elderly population

AIM To compare short term outcomes of elective laparoscopic and open right hemicolectomy (RH) in an elderly population. METHODS All patients over the age of 70 undergoing elective RH at Ninewells Hospital and Perth Royal Infirmary between January 2006 and May 2011 were included in our analysis. Operative details, hospital length of stay, morbidity and mortality was collected by way of proforma from a dedicated prospective database. An extracorporeal anastomosis was performed routinely in the laparoscopic group. The primary endpoints for analysis were morbidity and mortality. Our secondary endpoints were operative duration, length of hospital stay and discharge destination. RESULTS Two hundred and six patients were included in our analysis. One hundred and twenty-five patients underwent an open resection and 81 patients had a laparoscopic resection. The mean operating time was significantly longer in the laparoscopic group (139 ± 36 min vs 197 ± 53 min, P = 0.001). The mean length of hospital stay was similar in both groups (11.2 ± 7.8 d vs 9.6 ± 10.7 d, P = 0.28). The incidence of post-operative morbidities was 27% in the open group and 38% in the laparoscopic group (P = 0.12). Overall in-hospital mortality was 0.8% in open procedures vs 1% in laparoscopic. CONCLUSION Laparoscopic RH was associated with a significantly longer operative time compared to open RH. In our study, laparoscopic RH was not associated with reduced post-operative morbidity or significantly shorter length of hospital stay.

Uptake trends in the Scottish Bowel Screening Programme and the influences of age, sex, and deprivation:

Objective Age, sex, and deprivation are known factors influencing colorectal (bowel) cancer screening uptake. We investigated the influence of these factors on uptake over time. Methods Data from the Scottish Bowel Screening Programme (SBoSP) were collected between 2007 and 2014. End-points for analysis were uptake, faecal occult blood test positivity, and disease detection, adjusted for age, sex, deprivation, and year of screening. Results From 5,308,336 individual screening episodes documented, uptake gradually increased with increasing age up to 65–69 and was lower in men than women (52.4% vs. 58.7%, respectively). Deprivation had a significant effect on uptake by men and women of all age groups, with the most deprived least likely to complete a screening test. Uptake has increased with time in both sexes and across the deprivation gradient. The number needed to screen to detect significant neoplasia was significantly lower in men than women overall (170 vs. 365), and this held over all age and deprivation groups. The number needed to screen was also lower in the more deprived population. Conclusions Although lower age, male sex, and increased deprivation are associated with lower bowel cancer screening uptake in Scotland, uptake has increased since SBoSP introduction in all age groups, both sexes, and across the deprivation gradient. Despite a lower uptake, the number needed to screen to find significant disease was lower in men and in those with higher levels of deprivation.

Scottish Bowel Screening Programme colonoscopy quality - scope for improvement?

The delivery of the Scottish Bowel Screening Programme (SBoSP) is rooted in the provision of a high quality, effective and participant‐centred service. Safe and effective colonoscopy forms an integral part of the process. Additional accreditation as part of a multi‐faceted programme for participating colonoscopists, as in England, does not exist in Scotland. This study aimed to describe the quality of colonoscopy in the SBoSP and compare this to the English national screening standards.

Is familial adenomatous polyposis associated with sensorineural hearing loss

Abstract The mutation causing familial adenomatous polyposis (FAP) affects the adenomatous polyposis coli (Apc) gene, which has a role in the cytoskeleton and has been shown to be important in the structure of supporting cells in the cochlea. One previous study suggested that FAP sufferers may have sensorineural hearing loss. In order to demonstrate whether this is the case we invited patients known to suffer from familial adenomatous polyposis to take part in our study. Audiograms were performed and compared to normal values for that patients age and gender calculated using ISO standard data. Thirteen patients were included in the study analysis. No conductive hearing losses were identified. A statistically significant greater hearing loss was identified at 500 Hz (2.8 dBHL, P = 0.03) and 1000 Hz (2.5 dBHL, P = 0.05). No audiometric difference could be identified between the patients with FAP and attenuated FAP. A power calculation demonstrated that the study was of adequate size. This study did not demonstrate a clinically significant difference in hearing loss between the FAP group and the calculated normal values. Sumario La mutación que causa la poliposis adenomatosa familiar (FAP) afecta el gene polipomatosis adenomatosa coli (Apc), que tiene un papel cuya importancia en el citoesqueleto y en la estructura de las células de sostén de la cóclea se ha demostrado. Un estudio previo sugirió que quienes sufren la FAP pueden tener una pérdida auditiva sensorineural. Con objeto de demostrar si esto es así, invitamos a pacientes que (sabíamos) sufrían la enfermedad para tomar parte en este estudio. Los audiogramas que se practicaron fueron comparados con los valores normales de acuerdo con la edad y el género de los pacientes, usando los datos ISO estándar. Se incluyeron trece pacientes para el análisis del estudio. No se identificaron pérdidas auditivas conductivas. Si hubo una pérdida auditiva mayor, estadísticamente significativa en 500 Hz (2.8 dBHL, P = 0.03) y en 1000 Hz (2.5 dBHL, P = 0.05). No se pudo identificar una diferencia audiométrica entre los pacientes con FAP o con FAP atenuada. Un cálculo especial demostró que el estudio fue de un tamaño adecuado. Este estudio no mostró una diferencia clínicamente significativa de la pérdida auditiva entre el grupo con FAP y los valores calculados como normales.

Screening for colorectal cancer in defunctioned colons

Objectives Population-based colorectal (bowel) cancer screening using faecal occult blood tests leads to a reduction in cause-specific mortality. However, in people where the colon is defunctioned, the use of standard faecal occult blood test is not appropriate. The aim of this study was to examine the current trends of clinical practice for colorectal cancer screening in people with defunctioned colons. Methods An online survey was performed using SurveyMonkey. All members of the Association of Coloproctology of Great Britain and Ireland were invited by email to participate. Reminders were sent to non-responders and partial responders till six weeks. All responses were included in our analysis. Results Of the 206 (34.59%) questionnaires completed, all questions were answered in 110 (55.8%). Among responders, 94 (85.4%) were colorectal consultant surgeons, 72% had worked in their current capacity for more than five years, and 105 (50.9%) had encountered colorectal cancer in defunctioned colons during their career. Some 72.2% of responders stated that a screening test for colorectal cancer in patients with defunctioned colons was currently not offered, or that they did not know whether or not it was offered in their area. Conclusions Bowel screening in the United Kingdom is currently not offered to 72.2% of the age appropriate population with defunctioned colons. Among responding colorectal surgeons, 50% had encountered colorectal cancer in such patients. There is considerable variability in clinical practice regarding the optimal age for onset of screening, time interval, and the optimal modality to offer for screening in such cases.