Surgery (RMH) - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 18
-
ItemParametric imaging of the local attenuation coefficient in human axillary lymph nodes assessed using optical coherence tomography(OPTICAL SOC AMER, 2012-02-01)We report the use of optical coherence tomography (OCT) to determine spatially localized optical attenuation coefficients of human axillary lymph nodes and their use to generate parametric images of lymphoid tissue. 3D-OCT images were obtained from excised lymph nodes and optical attenuation coefficients were extracted assuming a single scattering model of OCT. We present the measured attenuation coefficients for several tissue regions in benign and reactive lymph nodes, as identified by histopathology. We show parametric images of the measured attenuation coefficients as well as segmented images of tissue type based on thresholding of the attenuation coefficient values. Comparison to histology demonstrates the enhancement of contrast in parametric images relative to OCT images. This enhancement is a step towards the use of OCT for in situ assessment of lymph nodes.
-
ItemInternational multicentre study examining selection criteria for active surveillance in men undergoing radical prostatectomy(NATURE PUBLISHING GROUP, 2012-10-23)BACKGROUND: The controversies concerning possible overtreatment of prostate cancer, highlighted by debate over PSA screening, have highlighted active surveillance (AS) as an alternative management option for appropriate men. Regional differences in the underlying prevalence of PSA testing may alter the pre-test probability for high-risk disease, which can potentially interfere with the performance of selection criteria for AS. In a multicentre study from three different countries, we examine men who were initially suitable for AS according to the Toronto and Prostate Cancer Research International: Active Surveillance (PRIAS) criteria, that underwent radical prostatectomy (RP) in regards to:1.the proportion of pathological reclassification(Gleason score ≥7, ≥pT3 disease),2.predictors of high-risk disease,3.create a predictive model to assist with selection of men suitable for AS. METHODS: From three centres in the United Kingdom, Canada and Australia, data on men who underwent RP were retrospectively reviewed (n=2329). Multivariable logistic regression was performed to identify predictors of high-risk disease. A nomogram was generated by logistic regression analysis, and performance characterised by receiver operating characteristic curves. RESULTS: For men suitable for AS according to the Toronto (n=800) and PRIAS (410) criteria, the rates for upgrading were 50.6, 42.7%, and upstaging 17.6, 12.4%, respectively. Significant predictors of high-risk disease were:•Toronto criteria: increasing age, cT2 disease, centre of diagnosis and number of positive cores.•PRIAS criteria: increasing PSA and cT2 disease.Cambridge had a high pT3a rate (26 vs 12%). To assist selection of men in the United Kingdom for AS, from the Cambridge data, we generated a nomogram predicting high-risk features in patients who meet the Toronto criteria (AUC of 0.72). CONCLUSION: The proportion of pathological reclassification in our cohort was higher than previously reported. Care must be used when applying the AS criteria generated from one population to another. With more stringent selection criteria, there is less reclassification but also fewer men who may benefit from AS.
-
ItemGenetic partitioning of interleukin-6 signalling in mice dissociates Stat3 from Smad3-mediated lung fibrosis(WILEY, 2012-09)Idiopathic pulmonary fibrosis (IPF) is a fatal disease that is unresponsive to current therapies and characterized by excessive collagen deposition and subsequent fibrosis. While inflammatory cytokines, including interleukin (IL)-6, are elevated in IPF, the molecular mechanisms that underlie this disease are incompletely understood, although the development of fibrosis is believed to depend on canonical transforming growth factor (TGF)-β signalling. We examined bleomycin-induced inflammation and fibrosis in mice carrying a mutation in the shared IL-6 family receptor gp130. Using genetic complementation, we directly correlate the extent of IL-6-mediated, excessive Stat3 activity with inflammatory infiltrates in the lung and the severity of fibrosis in corresponding gp130(757F) mice. The extent of fibrosis was attenuated in B lymphocyte-deficient gp130(757F);µMT(-/-) compound mutant mice, but fibrosis still occurred in their Smad3(-/-) counterparts consistent with the capacity of excessive Stat3 activity to induce collagen 1α1 gene transcription independently of canonical TGF-β/Smad3 signalling. These findings are of therapeutic relevance, since we confirmed abundant STAT3 activation in fibrotic lungs from IPF patients and showed that genetic reduction of Stat3 protected mice from bleomycin-induced lung fibrosis.
-
ItemCancer classification using the Immunoscore: a worldwide task force(BMC, 2012-10-03)Prediction of clinical outcome in cancer is usually achieved by histopathological evaluation of tissue samples obtained during surgical resection of the primary tumor. Traditional tumor staging (AJCC/UICC-TNM classification) summarizes data on tumor burden (T), presence of cancer cells in draining and regional lymph nodes (N) and evidence for metastases (M). However, it is now recognized that clinical outcome can significantly vary among patients within the same stage. The current classification provides limited prognostic information, and does not predict response to therapy. Recent literature has alluded to the importance of the host immune system in controlling tumor progression. Thus, evidence supports the notion to include immunological biomarkers, implemented as a tool for the prediction of prognosis and response to therapy. Accumulating data, collected from large cohorts of human cancers, has demonstrated the impact of immune-classification, which has a prognostic value that may add to the significance of the AJCC/UICC TNM-classification. It is therefore imperative to begin to incorporate the 'Immunoscore' into traditional classification, thus providing an essential prognostic and potentially predictive tool. Introduction of this parameter as a biomarker to classify cancers, as part of routine diagnostic and prognostic assessment of tumors, will facilitate clinical decision-making including rational stratification of patient treatment. Equally, the inherent complexity of quantitative immunohistochemistry, in conjunction with protocol variation across laboratories, analysis of different immune cell types, inconsistent region selection criteria, and variable ways to quantify immune infiltration, all underline the urgent requirement to reach assay harmonization. In an effort to promote the Immunoscore in routine clinical settings, an international task force was initiated. This review represents a follow-up of the announcement of this initiative, and of the J Transl Med. editorial from January 2012. Immunophenotyping of tumors may provide crucial novel prognostic information. The results of this international validation may result in the implementation of the Immunoscore as a new component for the classification of cancer, designated TNM-I (TNM-Immune).
-
ItemEarly rehabilitation in critical care (eRiCC): functional electrical stimulation with cycling protocol for a randomised controlled trial(BMJ PUBLISHING GROUP, 2012)INTRODUCTION: Intensive care-acquired weakness is a common problem, leads to significant impairment in physical functioning and muscle strength, and is prevalent in individuals with sepsis. Early rehabilitation has been shown to be safe and feasible; however, commencement is often delayed due to a patient's inability to co-operate. An intervention that begins early in an intensive care unit (ICU) admission without the need for patient volition may be beneficial in attenuating muscle wasting. The eRiCC (early rehabilitation in critical care) trial will investigate the effectiveness of functional electrical stimulation-assisted cycling and cycling alone, compared to standard care, in individuals with sepsis. METHODS AND ANALYSIS: This is a single centre randomised controlled trial. Participants (n=80) aged ≥18 years, with a diagnosis of sepsis or severe sepsis, who are expected to be mechanically ventilated for ≥48 h and remain in the intensive care ≥4 days will be randomised within 72 h of admission to (1) standard care or (2) intervention where participants will receive functional electrical muscle stimulation-assisted supine cycling on one leg while the other leg undergoes cycling alone. Primary outcome measures include: muscle mass (quadriceps ultrasonography; bioelectrical impedance spectroscopy); muscle strength (Medical Research Council Scale; hand-held dynamometry) and physical function (Physical Function in Intensive Care Test; Functional Status Score in intensive care; 6 min walk test). Blinded outcome assessors will assess measures at baseline, weekly, at ICU discharge and acute hospital discharge. Secondary measures will be evaluated in a nested subgroup (n=20) and will consist of biochemical/histological analyses of collected muscle, urine and blood samples at baseline and at ICU discharge. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the relevant institution, and results will be published to inform clinical practice in the care of patients with sepsis to optimise rehabilitation and physical function outcomes. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry ACTRN12612000528853.
-
ItemThe Gracilis Myocutaneous Free Flap: A Quantitative Analysis of the Fasciocutaneous Blood Supply and Implications for Autologous Breast Reconstruction(PUBLIC LIBRARY SCIENCE, 2012-05-09)BACKGROUND: Mastectomies are one of the most common surgical procedures in women of the developed world. The gracilis myocutaneous flap is favoured by many reconstructive surgeons due to the donor site profile and speed of dissection. The distal component of the longitudinal skin paddle of the gracilis myocutaneous flap is unreliable. This study quantifies the fasciocutaneous vascular territories of the gracilis flap and offers the potential to reconstruct breasts of all sizes. METHODS: Twenty-seven human cadaver dissections were performed and injected using lead oxide into the gracilis vascular pedicles, followed by radiographic studies to identify the muscular and fasciocutaneous perforator patterns. The vascular territories and choke zones were characterized quantitatively using the 'Lymphatic Vessel Analysis Protocol' (LVAP) plug-in for Image J® software. RESULTS: We found a step-wise decrease in the average vessel density from the upper to middle and lower thirds of both the gracilis muscle and the overlying skin paddle with a significantly higher average vessel density in the skin compared to the muscle. The average vessel width was greater in the muscle. Distal to the main pedicle, there were either one (7/27 cases), two (14/27 cases) or three (6/27 cases) minor pedicles. The gracilis angiosome was T-shaped and the maximum cutaneous vascular territory for the main and first minor pedicle was 35 × 19 cm and 34 × 10 cm, respectively. CONCLUSION: Our findings support the concept that small volume breast reconstructions can be performed on suitable patients, based on septocutaneous perforators from the minor pedicle without the need to harvest any muscle, further reducing donor site morbidity. For large reconstructions, if a 'T' or tri-lobed flap with an extended vertical component is needed, it is important to establish if three territories are present. Flap reliability and size may be optimized following computed tomographic angiography and surgical delay.
-
ItemLevels of a subpopulation of platelets, but not circulating endothelial cells, predict early treatment failure in prostate cancer patients after prostatectomy(NATURE PUBLISHING GROUP, 2012-10-23)BACKGROUND: Angiogenesis is one of the hallmarks of cancer driving tumour growth and ultimately metastasis. Circulating endothelial cells (CECs) and circulating endothelial progenitor (CEPs) cells have been reported as candidate surrogate markers for tumour vascularisation. Our aim was to investigate the potential use of these circulating cells levels as predictors of prostate cancer treatment failure and metastasis. METHODS: We examined the levels of CD31(+)CD45(-) cells (CECs) and CD31(+)CD45(-)CD117(+) (CEPs) in s.c. and orthotopic models of human prostate cancers and correlated measurements with tumour size, volume and microvessel density (MVD). We then performed a prospective cohort study in 164 men with localised prostate cancer undergoing prostatectomy. The CD31(+)CD45(-), CD31(+)CD45(-)CD146(+) (CECs) and CD31(+)CD45(intermediate)CD133(+) (CEPs) populations were quantified and subsequently enriched for further characterisation. RESULTS: In preclinical models, levels of CD31(+)CD45(-) cells, but not CEPs, were significantly elevated in tumour-bearing mice and correlated with tumour size, volume and MVD. In our human prospective cohort study, the levels of CD31(+)CD45(-) cells were significantly higher in men who experienced treatment failure within the first year, and on logistic regression analysis were an independent predictor of treatment failure, whereas neither levels of CECs or CEPs had any prognostic utility. Characterisation of the isolated CD31(+)CD45(-) cell population revealed an essentially homogenous population of large, immature platelets representing <0.1% of circulating platelets. CONCLUSION: Elevated levels of a distinct subpopulation of circulating platelets were an independent predictor for early biochemical recurrence in prostate cancer patients within the first year from prostatectomy.
-
ItemRefinement of the associations between risk of colorectal cancer and polymorphisms on chromosomes 1q41 and 12q13.13(OXFORD UNIV PRESS, 2012-02-15)In genome-wide association studies (GWASs) of colorectal cancer, we have identified two genomic regions in which pairs of tagging-single nucleotide polymorphisms (tagSNPs) are associated with disease; these comprise chromosomes 1q41 (rs6691170, rs6687758) and 12q13.13 (rs7163702, rs11169552). We investigated these regions further, aiming to determine whether they contain more than one independent association signal and/or to identify the SNPs most strongly associated with disease. Genotyping of additional sample sets at the original tagSNPs showed that, for both regions, the two tagSNPs were unlikely to identify a single haplotype on which the functional variation lay. Conversely, one of the pair of SNPs did not fully capture the association signal in each region. We therefore undertook more detailed analyses, using imputation, logistic regression, genealogical analysis using the GENECLUSTER program and haplotype analysis. In the 1q41 region, the SNP rs11118883 emerged as a strong candidate based on all these analyses, sufficient to account for the signals at both rs6691170 and rs6687758. rs11118883 lies within a region with strong evidence of transcriptional regulatory activity and has been associated with expression of PDGFRB mRNA. For 12q13.13, a complex situation was found: SNP rs7972465 showed stronger association than either rs11169552 or rs7136702, and GENECLUSTER found no good evidence for a two-SNP model. However, logistic regression and haplotype analyses supported a two-SNP model, in which a signal at the SNP rs706793 was added to that at rs11169552. Post-GWAS fine-mapping studies are challenging, but the use of multiple tools can assist in identifying candidate functional variants in at least some cases.
-
ItemIsolation and Characterization of Tumor Cells from the Ascites of Ovarian Cancer Patients: Molecular Phenotype of Chemoresistant Ovarian Tumors(PUBLIC LIBRARY SCIENCE, 2012-10-08)Tumor cells in ascites are a major source of disease recurrence in ovarian cancer patients. In an attempt to identify and profile the population of ascites cells obtained from ovarian cancer patients, a novel method was developed to separate adherent (AD) and non-adherent (NAD) cells in culture. Twenty-five patients were recruited to this study; 11 chemonaive (CN) and 14 chemoresistant (CR). AD cells from both CN and CR patients exhibited mesenchymal morphology with an antigen profile of mesenchymal stem cells and fibroblasts. Conversely, NAD cells had an epithelial morphology with enhanced expression of cancer antigen 125 (CA125), epithelial cell adhesion molecule (EpCAM) and cytokeratin 7. NAD cells developed infiltrating tumors and ascites within 12-14 weeks after intraperitoneal (i.p.) injections into nude mice, whereas AD cells remained non-tumorigenic for up to 20 weeks. Subsequent comparison of selective epithelial, mesenchymal and cancer stem cell (CSC) markers between AD and NAD populations of CN and CR patients demonstrated an enhanced trend in mRNA expression of E-cadherin, EpCAM, STAT3 and Oct4 in the NAD population of CR patients. A similar trend of enhanced mRNA expression of CD44, MMP9 and Oct4 was observed in the AD population of CR patients. Hence, using a novel purification method we demonstrate for the first time a distinct separation of ascites cells into epithelial tumorigenic and mesenchymal non-tumorigenic populations. We also demonstrate that cells from the ascites of CR patients are predominantly epithelial and show a trend towards increased mRNA expression of genes associated with CSCs, compared to cells isolated from the ascites of CN patients. As the tumor cells in the ascites of ovarian cancer patients play a dominant role in disease recurrence, a thorough understanding of the biology of the ascites microenvironment from CR and CN patients is essential for effective therapeutic interventions.
-
ItemThe connection between lymphangiogenic signalling and prostglandin biology: A missing link in the metastatsic pathway(IMPACT JOURNALS LLC, 2012-08)Substantial evidence supports important independent roles for lymphangiogenic growth factor signaling and prostaglandins in the metastatic spread of cancer. The significance of the lymphangiogenic growth factors, vascular endothelial growth factor (VEGF)-C and VEGF-D, is well established in animal models of metastasis, and a strong correlation exits between an increase in expression of VEGF-C and VEGF-D, and metastatic spread in various solid human cancers. Similarly, key enzymes that control the production of prostaglandins, cyclooxygenases (COX-1 and COX-2, prototypic targets of Non-steroidal anti-inflammatory drugs (NSAIDs)), are frequently over-expressed or de-regulated in the progression of cancer. Recent data have suggested an intersection of lymphangiogenic growth factor signaling and the prostaglandin pathways in the control of metastatic spread via the lymphatic vasculature. Furthermore, this correlates with current clinical data showing that some NSAIDs enhance the survival of cancer patients through reducing metastasis. Here, we discuss the potential biochemical and cellular basis for such anti-cancer effects of NSAIDs through the prostaglandin and VEGF signaling pathways.