Fantastic beasts and how to find them—Molecular identification of the mitochondrial ATP-sensitive potassium channel

Despite reported sightings over many years, certain mitochondrial-specific channels have proven to be elusive beasts, evading molecular identification. However, combining modern genetics with a wave of their ion-sensing wand, researchers have managed to capture first the mitochondrial calcium uniporter, and now that semi-mythological beast, the mitochondrial ATP-sensitive potassium (mitoKATP) channel

Imaging Mitochondrial Calcium Fluxes with Fluorescent Probes and Single- or Two-Photon Confocal Microscopy

The concentration of calcium ions in the mitochondria has been shown to affect its function, modulating respiratory activity at low levels and causing lethal damage at high concentrations. The rhodamine series of dyes can be used to measure mitochondrial calcium concentration, but the reliability of measurements depends upon correct partitioning of the dye within to the mitochondria. Methods are described to aid verification and quantification of the mitochondrial calcium concentration using single- or two-photon confocal microscopy. The method of linear unmixing to separate fluorescent signals based on either differing excitation or emission spectra is outlined and for the purposes of illustration is applied to the separation of rhod-2 signals originating from the dye within the mitochondria and nucleoli

Impact of Organizational Culture and Perceived Process Safety in the UAE Oil and Gas Industry

In the last few decades, there had been a lot of accidents in the oil and gas industry throughout the world. This article reports a qualitative study of 30 employees employed in the United Arab Emirates (UAE) oil and gas industry. Health, Safety, and Environment (HSE) culture is a concept which was studied in many researches. However, this research is set to examine how certain behaviors affect the safety performance in UAE’s oil and gas industry. Four core themes that were drawn from the interviewee discussions of how safety culture, leadership safety behaviors, supervisory safety behaviors, and employee training on safety affect the employee’s performance on safety. The emergent narratives on the safety culture showed that an employee was likely to perceive safety in the organization favorably if s/he believed that his/her role in ensuring process safety was critical. Moreover, results pertaining to supervisory safety culture showed that the safety culture promoted by a supervisor within his/her role often set the standard for his/her subordinates constituted the benchmark against which all his/her subordinates rated their own idea and practice of safety culture. In addition, the findings confirm the important role played by safety leadership, which entails leader-follower interactions where the former influences the achievement of safety goals. Lastly, it was emphasized that safety training stimulated employees with negative or indifferent attitudes towards safety to be more actively engaged in safety matters in the organization

Screening and Audit as Service-Level Strategies to Support Implementation of Australian Guidelines for Cancer Pain Management in Adults: A Feasibility Study

© 2019 Background: Pain in people with cancer is common but often under-recognized and under-treated. Guidelines can improve the quality of pain care, but need targeted strategies to support implementation. Aim: To test the feasibility of two service-level strategies for supporting guideline implementation: a screening system and medical record audit. Design: Multimethods. Setting: One oncology outpatient service, and one palliative care outpatient and inpatient service. Participants: Patients with advanced cancer. Methods: Patients were screened in the waiting room with a modified version of the Edmonton Symptom Assessment System-revised either electronically or in paper-based format. Feasibility indicated the percentage of patients successfully screened from the total number attending the services. An audit assessed adherence to key indicators of pain assessment and management. Feasibility thresholds were set at 75% incidence for screening and a median of 30 minutes per patient for audit. Results: Of 452 patient visits, 95% (n = 429)were successfully screened, 34% (n = 155)electronically and 61% (n = 274)paper-based. Electronic pain screening was technically challenging and time-intensive for nurses. Thirty-one patients consented to have their records audited. The median audit time was 37.5 minutes (range 10-120 minutes). Variability arose from the number and type of record (outpatient or inpatient). Adherence to indicators varied from 63% (pain assessment at first presentation)to 94% (regular pain assessment and medication prescribed at regular intervals). Conclusions: This study confirmed the need to implement evidence-based guidelines for cancer pain and generated useful insights into the feasibility of pain screening and audit

Global rigid registration of CT to video in laparoscopic liver surgery

PURPOSE: Image-guidance systems have the potential to aid in laparoscopic interventions by providing sub-surface structure information and tumour localisation. The registration of a preoperative 3D image with the intraoperative laparoscopic video feed is an important component of image guidance, which should be fast, robust and cause minimal disruption to the surgical procedure. Most methods for rigid and non-rigid registration require a good initial alignment. However, in most research systems for abdominal surgery, the user has to manually rotate and translate the models, which is usually difficult to perform quickly and intuitively. METHODS: We propose a fast, global method for the initial rigid alignment between a 3D mesh derived from a preoperative CT of the liver and a surface reconstruction of the intraoperative scene. We formulate the shape matching problem as a quadratic assignment problem which minimises the dissimilarity between feature descriptors while enforcing geometrical consistency between all the feature points. We incorporate a novel constraint based on the liver contours which deals specifically with the challenges introduced by laparoscopic data. RESULTS: We validate our proposed method on synthetic data, on a liver phantom and on retrospective clinical data acquired during a laparoscopic liver resection. We show robustness over reduced partial size and increasing levels of deformation. Our results on the phantom and on the real data show good initial alignment, which can successfully converge to the correct position using fine alignment techniques. Furthermore, since we can pre-process the CT scan before surgery, the proposed method runs faster than current algorithms. CONCLUSION: The proposed shape matching method can provide a fast, global initial registration, which can be further refined by fine alignment methods. This approach will lead to a more usable and intuitive image-guidance system for laparoscopic liver surgery

Intelligent viewpoint selection for efficient CT to video registration in laparoscopic liver surgery

PURPOSE: Minimally invasive surgery offers advantages over open surgery due to a shorter recovery time, less pain and trauma for the patient. However, inherent challenges such as lack of tactile feedback and difficulty in controlling bleeding lower the percentage of suitable cases. Augmented reality can show a better visualisation of sub-surface structures and tumour locations by fusing pre-operative CT data with real-time laparoscopic video. Such augmented reality visualisation requires a fast and robust video to CT registration that minimises interruption to the surgical procedure. METHODS: We propose to use view planning for efficient rigid registration. Given the trocar position, a set of camera positions are sampled and scored based on the corresponding liver surface properties. We implement a simulation framework to validate the proof of concept using a segmented CT model from a human patient. Furthermore, we apply the proposed method on clinical data acquired during a human liver resection. RESULTS: The first experiment motivates the viewpoint scoring strategy and investigates reliable liver regions for accurate registrations in an intuitive visualisation. The second experiment shows wider basins of convergence for higher scoring viewpoints. The third experiment shows that a comparable registration performance can be achieved by at least two merged high scoring views and four low scoring views. Hence, the focus could change from the acquisition of a large liver surface to a small number of distinctive patches, thereby giving a more explicit protocol for surface reconstruction. We discuss the application of the proposed method on clinical data and show initial results. CONCLUSION: The proposed simulation framework shows promising results to motivate more research into a comprehensive view planning method for efficient registration in laparoscopic liver surgery

On Pattern Selection for Laparoscope Calibration

Camera calibration is a key requirement for augmented reality in surgery. Calibration of laparoscopes provides two challenges that are not sufficiently addressed in the literature. In the case of stereo laparoscopes the small distance (less than 5mm) between the channels means that the calibration pattern is an order of magnitude more distant than the stereo separation. For laparoscopes in general, if an external tracking system is used, hand-eye calibration is difficult due to the long length of the laparoscope. Laparoscope intrinsic, stereo and hand-eye calibration all rely on accurate feature point selection and accurate estimation of the camera pose with respect to a calibration pattern. We compare 3 calibration patterns, chessboard, rings, and AprilTags. We measure the error in estimating the camera intrinsic parameters and the camera poses. Accuracy of camera pose estimation will determine the accuracy with which subsequent stereo or hand-eye calibration can be done. We compare the results of repeated real calibrations and simulations using idealised noise, to determine the expected accuracy of different methods and the sources of error. The results do indicate that feature detection based on rings is more accurate than a chessboard, however this doesn’t necessarily lead to a better calibration. Using a grid with identifiable tags enables detection of features nearer the image boundary, which may improve calibration

Deep residual networks for automatic segmentation of laparoscopic videos of the liver

MOTIVATION: For primary and metastatic liver cancer patients undergoing liver resection, a laparoscopic approach can reduce recovery times and morbidity while offering equivalent curative results; however, only about 10% of tumours reside in anatomical locations that are currently accessible for laparoscopic resection. Augmenting laparoscopic video with registered vascular anatomical models from pre-procedure imaging could support using laparoscopy in a wider population. Segmentation of liver tissue on laparoscopic video supports the robust registration of anatomical liver models by filtering out false anatomical correspondences between pre-procedure and intra-procedure images. In this paper, we present a convolutional neural network (CNN) approach to liver segmentation in laparoscopic liver procedure videos. METHOD: We defined a CNN architecture comprising fully-convolutional deep residual networks with multi-resolution loss functions. The CNN was trained in a leave-one-patient-out cross-validation on 2050 video frames from 6 liver resections and 7 laparoscopic staging procedures, and evaluated using the Dice score. RESULTS: The CNN yielded segmentations with Dice scores ≥0.95 for the majority of images; however, the inter-patient variability in median Dice score was substantial. Four failure modes were identified from low scoring segmentations: minimal visible liver tissue, inter-patient variability in liver appearance, automatic exposure correction, and pathological liver tissue that mimics non-liver tissue appearance. CONCLUSION: CNNs offer a feasible approach for accurately segmenting liver from other anatomy on laparoscopic video, but additional data or computational advances are necessary to address challenges due to the high inter-patient variability in liver appearance