Surgery (RMH) - Research Publications
Now showing items 1-12 of 100
A urinary microRNA signature can predict the presence of bladder urothelial carcinoma in patients undergoing surveillance
(NATURE PUBLISHING GROUP, 2016-02-16)
BACKGROUND: The objective of this study was to determine whether microRNA (miRNA) profiling of urine could identify the presence of urothelial carcinoma of the bladder (UCB) and to compare its performance characteristics to that of cystoscopy. METHODS: In the discovery cohort we screened 81 patients, which included 21 benign controls, 30 non-recurrers and 30 patients with active cancer (recurrers), using a panel of 12 miRNAs. Data analysis was performed using a machine learning approach of a Support Vector Machine classifier with a Student's t-test feature selection procedure. This was trained using a three-fold cross validation approach and performance was measured using the area under the receiver operator characteristic curve (AUC). The miRNA signature was validated in an independent cohort of a further 50 patients. RESULTS: The best predictor to distinguish patients with UCB from non-recurrers was achieved using a combination of six miRNAs (AUC=0.85). This validated in an independent cohort (AUC=0.74) and detected UCB with a high sensitivity (88%) and sufficient specificity (48%) with all significant cancers identified. The performance of the classifier was best in detecting clinically significant disease such as presence of T1 Stage disease (AUC=0.92) and high-volume disease (AUC=0.81). Cystoscopy rates in the validation cohort would have been reduced by 30%. CONCLUSIONS: Urinary profiling using this panel of miRNAs shows promise for detection of tumour recurrence in the surveillance of UCB. Such a panel may be useful in reducing the morbidity and costs associated with cystoscopic surveillance, and now merits prospective evaluation.
Prospective validation of the NCI Breast Cancer Risk Assessment Tool (Gail Model) on 40,000 Australian women
BACKGROUND: There is a growing interest in delivering more personalised, risk-based breast cancer screening protocols. This requires population-level validation of practical models that can stratify women into breast cancer risk groups. Few studies have evaluated the Gail model (NCI Breast Cancer Risk Assessment Tool) in a population screening setting; we validated this tool in a large, screened population. METHODS: We used data from 40,158 women aged 50-69 years (via the lifepool cohort) participating in Australia's BreastScreen programme. We investigated the association between Gail scores and future invasive breast cancer, comparing observed and expected outcomes by Gail score ranked groups. We also used machine learning to rank Gail model input variables by importance and then assessed the incremental benefit in risk prediction obtained by adding variables in order of diminishing importance. RESULTS: Over a median of 4.3 years, the Gail model predicted 612 invasive breast cancers compared with 564 observed cancers (expected/observed (E/O) = 1.09, 95% confidence interval (CI) 1.00-1.18). There was good agreement across decile groups of Gail scores (χ2 = 7.1, p = 0.6) although there was some overestimation of cancer risk in the top decile of our study group (E/O = 1.65, 95% CI 1.33-2.07). Women in the highest quintile (Q5) of Gail scores had a 2.28-fold increased risk of breast cancer (95% CI 1.73-3.02, p < 0.0001) compared with the lowest quintile (Q1). Compared with the median quintile, women in Q5 had a 34% increased risk (95% CI 1.06-1.70, p = 0.014) and those in Q1 had a 41% reduced risk (95% CI 0.44-0.79, p < 0.0001). Similar patterns were observed separately for women aged 50-59 and 60-69 years. The model's overall discrimination was modest (area under the curve (AUC) 0.59, 95% CI 0.56-0.61). A reduced Gail model excluding information on ethnicity and hyperplasia was comparable to the full Gail model in terms of correctly stratifying women into risk groups. CONCLUSIONS: This study confirms that the Gail model (or a reduced model excluding information on hyperplasia and ethnicity) can effectively stratify a screened population aged 50-69 years according to the risk of future invasive breast cancer. This information has the potential to enable more personalised, risk-based screening strategies that aim to improve the balance of the benefits and harms of screening.
Influence of continuous electrical stimulation on development of human cardiomyocytes from induced pluripotent stem cells
(Conditioning Medicine, 2018)
Regeneration of cardiac tissue remains an ideal approach to restore cardiac function after myocardial infarction. The ability of human induced pluripotent stem cells (iPSCs) to differentiate into bona fide cardiomyocytes also provides a platform for cardiac disease modeling, drug discovery and pharmacological safety testing of new drugs. One of the major limitations for the use of cardiomyocytes derived from iPSCs is that they resemble fetal cardiomyocytes and are immature compared to adult cardiomyocytes. Considering that the developing heart grows in an electric field, we investigated whether electrical stimulation can promote maturation of cardiomyocytes derived from human iPSCs. Two-dimensional cultures of immature cardiomyocytes at day 22 post-differentiation were subjected to continuous electrical stimulation at 200 mV/mm for 7 days using a custom-made electrical stimulator. This long-term electrical stimulation significantly increased the percentage of cardiomyocytes with organized sarcomeres and promoted alignment of cardiomyocytes parallel to the electric field. Electrical stimulation also decreased the circularity index of cardiomyocytes suggesting a more rod-like morphology. In conclusion, long-term continuous electrical stimulation promotes maturation of cardiomyocytes derived from human iPSCs. Mature cardiomyocytes can better recapitulate the pathophysiological conditions of the human heart for more accurate disease modeling and drug testing. Mature cardiomyocytes can also provide a substrate for cardiac regeneration and repair by tissue engineering in the future.
Screening of CRISPR/Cas base editors to target the AMD high-risk Y402H complement factor H variant
(MOLECULAR VISION, 2019-03-16)
Purpose: To evaluate the efficacy of using a CRISPR/Cas-mediated strategy to correct a common high-risk allele that is associated with age-related macular degeneration (AMD; rs1061170; NM_000186.3:c.1204T>C; NP_000177.2:p.His402Tyr) in the complement factor H (CFH) gene. Methods: A human embryonic kidney cell line (HEK293A) was engineered to contain the pathogenic risk variant for AMD (HEK293A-CFH). Several different base editor constructs (BE3, SaBE3, SaKKH-BE3, VQR-BE3, and Target-AID) and their respective single-guide RNA (sgRNA) expression cassettes targeting either the pathogenic risk variant allele in the CFH locus or the LacZ gene, as a negative control, were evaluated head-to-head for the incidence of a cytosine-to-thymine nucleotide correction. The base editor construct that showed appreciable editing activity was selected for further assessment in which the base-edited region was subjected to next-generation deep sequencing to quantify on-target and off-target editing efficacy. Results: The tandem use of the Target-AID base editor and its respective sgRNA demonstrated a base editing efficiency of facilitating a cytosine-to-thymine nucleotide correction in 21.5% of the total sequencing reads. Additionally, the incidence of insertions and deletions (indels) was detected in only 0.15% of the sequencing reads with virtually no off-target effects evident across the top 11 predicted off-target sites containing at least one cytosine in the activity window (n = 3, pooled amplicons). Conclusions: CRISPR-mediated base editing can be used to facilitate a permanent and stably inherited cytosine-to-thymine nucleotide correction of the rs1061170 SNP in the CFH gene with minimal off-target effects.
The Sternal Management Accelerated Recovery Trial (SMART) - standard restrictive versus an intervention of modified sternal precautions following cardiac surgery via median sternotomy: study protocol for a randomised controlled trial
BACKGROUND: The routine implementation of sternal precautions to prevent sternal complications that restrict the use of the upper limbs is currently worldwide practice following a median sternotomy. However, evidence is limited and drawn primarily from cadaver studies and orthopaedic research. Sternal precautions may delay recovery, prolong hospital discharge and be overly restrictive. Recent research has shown that upper limb exercise reduces post-operative sternal pain and results in minimal micromotion between the sternal edges as measured by ultrasound. The aims of this study are to evaluate the effects of modified sternal precautions on physical function, pain, recovery and health-related quality of life after cardiac surgery. METHODS/DESIGN: This study is a phase II, double-blind, randomised controlled trial with concealed allocation, blinding of patients and assessors, and intention-to-treat analysis. Patients (n = 72) will be recruited following cardiac surgery via a median sternotomy. Sample size calculations were based on the minimal important difference (two points) for the primary outcome: Short Physical Performance Battery. Thirty-six participants are required per group to counter dropout (20%). All participants will be randomised to receive either standard or modified sternal precautions. The intervention group will receive guidelines encouraging the safe use of the upper limbs. Secondary outcomes are upper limb function, pain, kinesiophobia and health-related quality of life. Descriptive statistics will be used to summarise data. The primary hypothesis will be examined by repeated-measures analysis of variance to evaluate the changes from baseline to 4 weeks post-operatively in the intervention arm compared with the usual-care arm. In all tests to be conducted, a p value <0.05 (two-tailed) will be considered statistically significant, and confidence intervals will be reported. DISCUSSION: The Sternal Management Accelerated Recovery Trial (S.M.A.R.T.) is a two-centre randomised controlled trial powered and designed to investigate whether the effects of modifying sternal precautions to include the safe use of the upper limbs and trunk impact patients' physical function and recovery following cardiac surgery via median sternotomy. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry identifier: ACTRN12615000968572 . Registered on 16 September 2015 (prospectively registered).
Focused cardiac ultrasound is feasible in the general practice setting and alters diagnosis and management of cardiac disease
(BIOSCIENTIFICA LTD, 2016-09-01)
BACKGROUND: Ultrasound-assisted examination of the cardiovascular system with focused cardiac ultrasound by the treating physician is non-invasive and changes diagnosis and management of patient's with suspected cardiac disease. This has not been reported in a general practice setting. AIM: To determine whether focused cardiac ultrasound performed on patients aged over 50 years changes the diagnosis and management of cardiac disease by a general practitioner. DESIGN AND SETTING: A prospective observational study of 80 patients aged over 50years and who had not received echocardiography or chest CT within 12months presenting to a general practice. METHOD: Clinical assessment and management of significant cardiac disorders in patients presenting to general practitioners were recorded before and after focused cardiac ultrasound. Echocardiography was performed by a medical student with sufficient training, which was verified by an expert. Differences in diagnosis and management between conventional and ultrasound-assisted assessment were recorded. RESULTS AND CONCLUSION: Echocardiography and interpretation were acceptable in all patients. Significant cardiac disease was detected in 16 (20%) patients, including aortic stenosis in 9 (11%) and cardiac failure in 7 (9%), which were missed by clinical examination in 10 (62.5%) of these patients. Changes in management occurred in 12 patients (15% overall and 75% of those found to have significant cardiac disease) including referral for diagnostic echocardiography in 8 (10%), commencement of heart failure treatment in 3 (4%) and referral to a cardiologist in 1 patient (1%).Routine focused cardiac ultrasound is feasible and frequently alters the diagnosis and management of cardiac disease in patients aged over 50years presenting to a general practice.
Ponatinib: a novel multi-tyrosine kinase inhibitor against human malignancies
(DOVE MEDICAL PRESS LTD, 2019-01-01)
Human malignancies are often the result of overexpressed and constitutively active receptor and non-receptor tyrosine kinases, which ultimately lead to the mediation of key tumor-driven pathways. Several tyrosine kinases (ie, EGFR, FGFR, PDGFR, VEGFR), are aberrantly activated in most common tumors, including leukemia, glioblastoma, gastrointestinal stromal tumors, non-small-cell lung cancer, and head and neck cancers. Iclusig™ (ponatinib, previously known as AP24534) is an orally active multi-tyrosine kinase inhibitor and is currently approved by the US Food and Drug Administration for patients with chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia, specifically targeting the BCR-ABL gene mutation, T315I. Due to ponatinib's unique multi-targeted characteristics, further studies have demonstrated its ability to target other important tyrosine kinases (FGFR, PDGFR, SRC, RET, KIT, and FLT1) in other human malignancies. This review focuses on the available data of ponatinib and its molecular targets for treatment in various cancers, with a discussion on the broader potential of this agent in other cancer indications.
Whole-body ultrasound in the intensive care unit
(Health management.org, 2018)
Whole-body ultrasound can be used in the evaluation of many critical conditions including encephalopathy where brain and ocular ultrasound combined with transcranial Doppler can identify elevated intracranial pressure. Hypoxaemia is mostly related to pulmonary disease and lung ultrasound can rapidly identify the aetiology. Cardiac, lung and abdominal ultrasound will be useful to identify both the mechanism and aetiology of haemodynamic instability. Finally, in any oligo-anuric patient, renal ultrasound should be performed. The use of ultrasound is further supported by several prospective and randomised trials.
The impact of heart, lung and diaphragmatic ultrasound on prediction of failed extubation from mechanical ventilation in critically ill patients: a prospective observational pilot study
BACKGROUND: Failed extubation from mechanical ventilation in critically ill patients is multifactorial, complex and not well understood. We aimed to identify whether combined transthoracic echocardiography, lung and diaphragmatic ultrasound can predict extubation failure in critically ill patients. RESULTS: Fifty-three participants who were intubated > 48 h and deemed by the treating intensivist ready for extubation underwent a 60-min pre-extubation weaning trial (pressure support ≤ 10 cmH2O and positive end expiratory pressure 5 cmH2O). Prior to extubation, data collected included ultrasound assessment of left ventricular ejection fraction, left atrial area, early diastolic trans-mitral flow velocity wave (E), early diastolic trans-mitral flow velocity wave/late diastolic trans-mitral flow velocity wave (E/A), early diastolic trans-mitral flow velocity wave/early diastolic mitral annulus velocity (E/E'), interatrial septal motion, lung loss of aeration score and diaphragm movement. At the end of the weaning trial, the rapid shallow breathing index and serum B-type natriuretic peptide concentration were measured. Success and failure of weaning was assessed by defined criteria. Decision to extubate was at the discretion of the treating intensivist. Failure of extubation was defined as re-intubation, non-invasive ventilation or death within 48 h after extubation. Of 53 extubated participants, 11 failed extubation. Failed extubation was associated with diabetes, ischaemic heart disease, higher E/E' (OR 1.27, 95% CI 1.05-1.54), left atrial area (OR 1.14, CI 1.02-1.28), fixed rightward curvature of the interatrial septum (OR 12.95, CI 2.73-61.41), and higher loss of aeration score of anterior and lateral regions of the lungs (OR 1.41, CI 1.01-1.82). CONCLUSIONS: Failed extubation in mechanically ventilated patients is more prevalent if markers of left ventricular diastolic dysfunction and loss of lung aeration are present.
First interim analysis of a randomised trial of whole brain radiotherapy in melanoma brain metastases confirms high data quality.
BACKGROUND: Brain metastases are a common cause of death in patients with melanoma. The role of adjuvant whole brain radiotherapy (WBRT) following local treatment of intracranial melanoma metastases is controversial. The Australian and New Zealand Melanoma Trials Group (ANZMTG) and the Trans-Tasman Radiation Oncology Group (TROG) are leading the first ever single histology randomised trial investigating this question. The primary endpoint is distant intracranial failure on magnetic resonance imaging (MRI) within twelve months of randomisation. The first planned interim analysis was performed twelve months after randomisation of the 100(th) patient. The analysis was an opportunity to review completeness of the trial data to date. METHODS: All data received up to the end of twelve months after randomisation of the 100th patient was reviewed. RESULTS: Review of pathology reports confirmed that all 100 patients had stage IV melanoma and were appropriately entered into the study. Of the 47 distant intracranial events, 34 occurred in isolation (i.e. only distant failure was identified), whilst 13 were accompanied by local failure. Data review showed compliance with the protocol mandated MRI schedule and accuracy of intracranial failure reporting was very high. The Quality of Life (QoL) component of the study achieved a 91% completion rate. For the neurocognitive function (NCF) assessments, a high completion rate was maintained throughout the 12 month period. Where assessments were not performed at expected time points, valid reasons were noted. Radiotherapy quality was high. Of 50 patients who received WBRT, 32 were reviewed as per protocol design and there was only one major variation out of 308 data points reviewed (0.3%). There were minimal trial related adverse events (AEs) and no serious adverse events (SAEs). Pre-specified protocol stopping rules were not met. CONCLUSIONS: The Data Safety Monitoring Committee (DSMC) recommended the trial continue recruitment after reviewing the unblinded data. The data provision and quality to date indicates that a reliable outcome will be obtained when the final analysis is performed. Accrual is ongoing with 156 out of 200 patients randomised to date (26(th) November 2014).