Publications by authors named "Anthony Lin"

25 Publications

  • Page 1 of 1

Body Weight Changes During Pandemic-Related Shelter-in-Place in a Longitudinal Cohort Study.

JAMA Netw Open 2021 03 1;4(3):e212536. Epub 2021 Mar 1.

Division of Cardiology, Department of Medicine, University of California, San Francisco.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1001/jamanetworkopen.2021.2536DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7985720PMC
March 2021

ManoMap: an automated system for characterization of colonic propagating contractions recorded by high-resolution manometry.

Med Biol Eng Comput 2021 Feb 26;59(2):417-429. Epub 2021 Jan 26.

Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.

Rationale: Colonic high-resolution manometry (cHRM) is an emerging clinical tool for defining colonic function in health and disease. Current analysis methods are conducted manually, thus being inefficient and open to interpretation bias.

Objective: The main objective of the study was to build an automated system to identify propagating contractions and compare the performance to manual marking analysis.

Methods: cHRM recordings were performed on 5 healthy subjects, 3 subjects with diarrhea-predominant irritable bowel syndrome, and 3 subjects with slow transit constipation. Two experts manually identified propagating contractions, from five randomly selected 10-min segments from each of the 11 subjects (72 channels per dataset, total duration 550 min). An automated signal processing and detection platform was developed to compare its effectiveness to manually identified propagating contractions. In the algorithm, individual pressure events over a threshold were identified and were then grouped into a propagating contraction. The detection platform allowed user-selectable thresholds, and a range of pressure thresholds was evaluated (2 to 20 mmHg).

Key Results: The automated system was found to be reliable and accurate for analyzing cHRM with a threshold of 15 mmHg, resulting in a positive predictive value of 75%. For 5-h cHRM recordings, the automated method takes 22 ± 2 s for analysis, while manual identification would take many hours.

Conclusions: An automated framework was developed to filter, detect, quantify, and visualize propagating contractions in cHRM recordings in an efficient manner that is reliable and consistent.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11517-021-02316-yDOI Listing
February 2021

Naproxen treatment inhibits articular cartilage loss in a rat model of osteoarthritis.

J Orthop Res 2020 Dec 4. Epub 2020 Dec 4.

Department of Orthopaedics, Rutgers-New Jersey Medical School, Newark, New Jersey, USA.

The effects of naproxen, a nonsteroidal anti-inflammatory drug (NSAID), on articular cartilage degeneration in female Sprague-Dawley rats was examined. Osteoarthritis (OA) was induced by destabilization of the medial meniscus (DMM) in each knee. Rats were treated with acetaminophen (60 mg/kg), naproxen (8 mg/kg), or 1% carboxymethylcellulose (placebo) by oral gavage twice daily for 3 weeks, beginning 2 weeks after surgery. OA severity was assessed by histological Osteoarthritis Research Society International (OARSI) scoring and by measuring proximal tibia cartilage depth using contrast enhanced µCT (n = 6 per group) in specimens collected at 2, 5, and 7 weeks after surgery as well as on pristine knees. Medial cartilage OARSI scores from the DMM knees of naproxen-treated rats were statistically lower (i.e., better) than the medial cartilage OARSI scores from the DMM knees of placebo-treated rats at 5-weeks (8.7 ± 3.6 vs. 13.2 ± 2.4, p = 0.025) and 7-weeks (9.5 ± 1.2 vs. 12.5 ± 2.5, p = 0.024) after surgery. At 5 weeks after DMM surgery, medial articular cartilage depth in the proximal tibia specimens was significantly greater in the naproxen (1.78 ± 0.26 mm, p = 0.005) and acetaminophen (1.94 ± 0.12 mm, p < 0.001) treated rats as compared with placebo-treated rats (1.34 ± 0.24 mm). However, at 7 weeks (2 weeks after drug withdrawal), medial articular cartilage depth for acetaminophen-treated rats (1.36 ± 0.29 mm) was significantly reduced compared with specimens from the naproxen-treated rats (1.88 ± 0.14 mm; p = 0.004). The results indicate that naproxen treatment reduced articular cartilage degradation in the rat DMM model during and after naproxen treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jor.24937DOI Listing
December 2020

Integrating a Machine Learning System Into Clinical Workflows: Qualitative Study.

J Med Internet Res 2020 11 19;22(11):e22421. Epub 2020 Nov 19.

Duke Institute for Health Innovation, Durham, NC, United States.

Background: Machine learning models have the potential to improve diagnostic accuracy and management of acute conditions. Despite growing efforts to evaluate and validate such models, little is known about how to best translate and implement these products as part of routine clinical care.

Objective: This study aims to explore the factors influencing the integration of a machine learning sepsis early warning system (Sepsis Watch) into clinical workflows.

Methods: We conducted semistructured interviews with 15 frontline emergency department physicians and rapid response team nurses who participated in the Sepsis Watch quality improvement initiative. Interviews were audio recorded and transcribed. We used a modified grounded theory approach to identify key themes and analyze qualitative data.

Results: A total of 3 dominant themes emerged: perceived utility and trust, implementation of Sepsis Watch processes, and workforce considerations. Participants described their unfamiliarity with machine learning models. As a result, clinician trust was influenced by the perceived accuracy and utility of the model from personal program experience. Implementation of Sepsis Watch was facilitated by the easy-to-use tablet application and communication strategies that were developed by nurses to share model outputs with physicians. Barriers included the flow of information among clinicians and gaps in knowledge about the model itself and broader workflow processes.

Conclusions: This study generated insights into how frontline clinicians perceived machine learning models and the barriers to integrating them into clinical workflows. These findings can inform future efforts to implement machine learning interventions in real-world settings and maximize the adoption of these interventions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2196/22421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7714645PMC
November 2020

Correction to: High‑Resolution Colonic Manometry Pressure Profiles Are Similar in Asymptomatic Diverticulosis and Controls.

Dig Dis Sci 2021 Apr;66(4):1372-1374

Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10620-020-06524-8DOI Listing
April 2021

Machine learning for early detection of sepsis: an internal and temporal validation study.

JAMIA Open 2020 Jul 11;3(2):252-260. Epub 2020 Apr 11.

Department of Medicine, Durham, North Carolina, USA.

Objective: Determine if deep learning detects sepsis earlier and more accurately than other models. To evaluate model performance using implementation-oriented metrics that simulate clinical practice.

Materials And Methods: We trained internally and temporally validated a deep learning model (multi-output Gaussian process and recurrent neural network [MGP-RNN]) to detect sepsis using encounters from adult hospitalized patients at a large tertiary academic center. Sepsis was defined as the presence of 2 or more systemic inflammatory response syndrome (SIRS) criteria, a blood culture order, and at least one element of end-organ failure. The training dataset included demographics, comorbidities, vital signs, medication administrations, and labs from October 1, 2014 to December 1, 2015, while the temporal validation dataset was from March 1, 2018 to August 31, 2018. Comparisons were made to 3 machine learning methods, random forest (RF), Cox regression (CR), and penalized logistic regression (PLR), and 3 clinical scores used to detect sepsis, SIRS, quick Sequential Organ Failure Assessment (qSOFA), and National Early Warning Score (NEWS). Traditional discrimination statistics such as the C-statistic as well as metrics aligned with operational implementation were assessed.

Results: The training set and internal validation included 42 979 encounters, while the temporal validation set included 39 786 encounters. The C-statistic for predicting sepsis within 4 h of onset was 0.88 for the MGP-RNN compared to 0.836 for RF, 0.849 for CR, 0.822 for PLR, 0.756 for SIRS, 0.619 for NEWS, and 0.481 for qSOFA. MGP-RNN detected sepsis a median of 5 h in advance. Temporal validation assessment continued to show the MGP-RNN outperform all 7 clinical risk score and machine learning comparisons.

Conclusions: We developed and validated a novel deep learning model to detect sepsis. Using our data elements and feature set, our modeling approach outperformed other machine learning methods and clinical scores.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jamiaopen/ooaa006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7382639PMC
July 2020

Real-World Integration of a Sepsis Deep Learning Technology Into Routine Clinical Care: Implementation Study.

JMIR Med Inform 2020 Jul 15;8(7):e15182. Epub 2020 Jul 15.

Department of Medicine, Duke University School of Medicine, Durham, NC, United States.

Background: Successful integrations of machine learning into routine clinical care are exceedingly rare, and barriers to its adoption are poorly characterized in the literature.

Objective: This study aims to report a quality improvement effort to integrate a deep learning sepsis detection and management platform, Sepsis Watch, into routine clinical care.

Methods: In 2016, a multidisciplinary team consisting of statisticians, data scientists, data engineers, and clinicians was assembled by the leadership of an academic health system to radically improve the detection and treatment of sepsis. This report of the quality improvement effort follows the learning health system framework to describe the problem assessment, design, development, implementation, and evaluation plan of Sepsis Watch.

Results: Sepsis Watch was successfully integrated into routine clinical care and reshaped how local machine learning projects are executed. Frontline clinical staff were highly engaged in the design and development of the workflow, machine learning model, and application. Novel machine learning methods were developed to detect sepsis early, and implementation of the model required robust infrastructure. Significant investment was required to align stakeholders, develop trusting relationships, define roles and responsibilities, and to train frontline staff, leading to the establishment of 3 partnerships with internal and external research groups to evaluate Sepsis Watch.

Conclusions: Machine learning models are commonly developed to enhance clinical decision making, but successful integrations of machine learning into routine clinical care are rare. Although there is no playbook for integrating deep learning into clinical care, learnings from the Sepsis Watch integration can inform efforts to develop machine learning technologies at other health care delivery systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2196/15182DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7391165PMC
July 2020

High-Resolution Colonic Manometry Pressure Profiles Are Similar in Asymptomatic Diverticulosis and Controls.

Dig Dis Sci 2021 Mar 12;66(3):832-842. Epub 2020 May 12.

Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.

Background: Elevated colonic pressures and increased colonic activity have been thought to contribute to the pathophysiology of diverticulosis. However, evidence for this has been limited to low-resolution manometry, which is of limited accuracy.

Aims: This study aimed to evaluate the contraction pressures, counts, and distance of propagation recorded by high-resolution colonic manometry in diverticulosis vs control patients.

Methods: High-resolution colonic manometry was used to record descending and sigmoid colon activity pre- and post-meal in patients with established, asymptomatic diverticulosis and in healthy controls. Antegrade and retrograde propagating contractions, distance of propagation (mm), and mean contraction pressures (mmHg) in the descending and sigmoid colon were compared between patients and controls for all isolated propagating contractions, the cyclic motor pattern, and high-amplitude propagating contractions independently.

Results: Mean manometry pressures were not different between controls and diverticulosis patients (p > 0.05 for all comparisons). In the descending colon, diverticulosis patients had lower post-meal mean distance of propagation for all propagating contractions [10.8 (SE1.5) mm vs 20.0 (2.0) mm, p = 0.003] and the cyclic motor pattern [6.0 (2.5) mm vs 17.1 (2.8) mm, p = 0.01]. In the sigmoid colon, diverticulosis patients showed lower post-meal mean distance of propagation for all propagating contractions [10.8 (1.5) mm vs 20.2 (5.9) mm, p = 0.01] and a lower post-meal increase in retrograde propagating contractions (p = 0.04).

Conclusions: In this first high-resolution colonic manometry study of patients with diverticular disease, we did not find evidence for increased manometric pressures or increased colonic activity in patients with diverticular disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10620-020-06320-4DOI Listing
March 2021

Antibiotics Do Not Reduce Length of Hospital Stay for Uncomplicated Diverticulitis in a Pragmatic Double-Blind Randomized Trial.

Clin Gastroenterol Hepatol 2021 Mar 30;19(3):503-510.e1. Epub 2020 Mar 30.

Department of Surgery, University of Auckland, Auckland, New Zealand; Colorectal Unit, Department of Surgery, Auckland District Health Board, Auckland, New Zealand. Electronic address:

Background & Aims: Antibiotic treatment is the standard care for patients with uncomplicated acute diverticulitis. However, this practice is based on low-level evidence and has been challenged by findings from 2 randomized trials, which did not include a placebo group. We investigated the non-inferiority of placebo vs antibiotic treatment for the management of uncomplicated acute diverticulitis.

Methods: In the selective treatment with antibiotics for non-complicated diverticulitis study, 180 patients hospitalized for uncomplicated acute diverticulitis (determined by computed tomography, Hinchey 1a grade) from New Zealand and Australia were randomly assigned to groups given antibiotics (n = 85) or placebo (n = 95) for 7 days. We collected demographic, clinical, and laboratory data and answers to questionnaires completed every 12 hrs for the first 48 hrs and then daily until hospital discharge. The primary endpoint was length of hospital stay; secondary endpoints included occurrence of adverse events, readmission to the hospital, procedural intervention, change in serum markers of inflammation, and patient-reported pain scores at 12 and 24 hrs.

Results: There was no significant difference in median time of hospital stay between the antibiotic group (40.0 hrs; 95% CI, 24.4-57.6 hrs) and the placebo group (45.8 hrs; 95% CI, 26.5-60.2 hrs) (P = .2). There were no significant differences between groups in adverse events (12% for both groups; P = 1.0), readmission to the hospital within 1 week (1% for the placebo group vs 6% for the antibiotic group; P = .1), and readmission to the hospital within 30 days (11% for the placebo group vs 6% for the antibiotic group; P = .3).

Conclusions: Foregoing antibiotic treatment did not prolong length of hospital admission. This result provides strong evidence for omission of antibiotics for selected patients with uncomplicated acute diverticulitis.

Actrn:  12615000249550.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cgh.2020.03.049DOI Listing
March 2021

Development and feasibility of an ambulatory acquisition system for fiber-optic high-resolution colonic manometry.

Neurogastroenterol Motil 2019 12 13;31(12):e13704. Epub 2019 Aug 13.

Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.

Background: High-resolution colonic manometry is an emerging technique that has provided new insights into the pathophysiology of functional colorectal diseases. Prior studies have been limited by bulky, non-ambulatory acquisition systems, which have prevented mobilization during prolonged recordings.

Methods: A novel ambulatory acquisition system for fiber-optic high-resolution colonic manometry was developed. Benchtop validation against a standard non-ambulatory system was performed using standardized calibration metrics. Clinical feasibility studies were conducted in three patients undergoing right hemicolectomy.

Results: Pressure profiles obtained from benchtop testing were near-identical using the ambulatory and the non-ambulatory systems. Clinical studies successfully demonstrated ambulatory data capture with patients freely mobilizing postoperatively during continuous recordings of >60 hours. The occurrence (P = .56), amplitude (P = .65), velocity (P = .10), and extent (P = .12) of colonic motor patterns were similar to those obtained in non-ambulatory studies.

Conclusions: A novel ambulatory system for high-resolution colonic manometry has been developed and validated. This technique will facilitate prolonged ambulatory recordings of colonic motor activity, assisting with investigations into the role of colonic motility in disease states.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nmo.13704DOI Listing
December 2019

Bilirubin Links Heme Metabolism to Neuroprotection by Scavenging Superoxide.

Cell Chem Biol 2019 10 25;26(10):1450-1460.e7. Epub 2019 Jul 25.

The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Electronic address:

Bilirubin is one of the most frequently measured metabolites in medicine, yet its physiologic roles remain unclear. Bilirubin can act as an antioxidant in vitro, but whether its redox activity is physiologically relevant is unclear because many other antioxidants are far more abundant in vivo. Here, we report that depleting endogenous bilirubin renders mice hypersensitive to oxidative stress. We find that mice lacking bilirubin are particularly vulnerable to superoxide (O) over other tested reactive oxidants and electrophiles. Whereas major antioxidants such as glutathione and cysteine exhibit little to no reactivity toward O, bilirubin readily scavenges O. We find that bilirubin's redox activity is particularly important in the brain, where it prevents excitotoxicity and neuronal death by scavenging O during NMDA neurotransmission. Bilirubin's unique redox activity toward O may underlie a prominent physiologic role despite being significantly less abundant than other endogenous and exogenous antioxidants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chembiol.2019.07.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893848PMC
October 2019

Machine Learning in Health Care: A Critical Appraisal of Challenges and Opportunities.

EGEMS (Wash DC) 2019 Jan 24;7(1). Epub 2019 Jan 24.

Duke Institute for Health Innovation, US.

Examples of fully integrated machine learning models that drive clinical care are rare. Despite major advances in the development of methodologies that outperform clinical experts and growing prominence of machine learning in mainstream medical literature, major challenges remain. At Duke Health, we are in our fourth year developing, piloting, and implementing machine learning technologies in clinical care. To advance the translation of machine learning into clinical care, health system leaders must address barriers to progress and make strategic investments necessary to bring health care into a new digital age. Machine learning can improve clinical workflows in subtle ways that are distinct from how statistics has shaped medicine. However, most machine learning research occurs in siloes, and there are important, unresolved questions about how to retrain and validate models post-deployment. Academic medical centers that cultivate and value transdisciplinary collaboration are ideally suited to integrate machine learning in clinical care. Along with fostering collaborative environments, health system leaders must invest in developing new capabilities within the workforce and technology infrastructure beyond standard electronic health records. Now is the opportunity to break down barriers and achieve scalable growth in the number of high-impact collaborations between clinical researchers and machine learning experts to transform clinical care.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5334/egems.287DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6354017PMC
January 2019

Patching a leak in an R1 university gateway STEM course.

PLoS One 2018 6;13(9):e0202041. Epub 2018 Sep 6.

Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301, United States of America.

A cognitively intensive companion service course has been introduced to the main fall general chemistry class at Cornell University. For years 2015 and 2016, priority students (those from groups under-represented and economically disadvantaged) show respectively improvement of +0.67 and +0.51 standard deviations in final course grade compared to priority students not in the program. Non-priority students show respectively a +0.66 and +0.62 standard deviation improvement. Progressive improvement (as measured by higher than expected Final Exam scores than what would have been expected solely from a given student's earlier Exam 1 score) demonstrates conclusively the service course's role in the enhanced outcomes. Progressive retention (as measured by the following year fall semester's organic chemistry exam scores compared to what would have been expected based on a given student's general chemistry final exam score) demonstrates that, on the average, the earlier observed progressive improvement is significantly retained in a chemistry course one year later. Preliminary retention statistics suggest a significant increase in first year to second year retention. A meta analysis of results from previously reported chemistry service courses indicate that such performance gains are difficult to achieve and hence common elements of the few effective programs may be of high value to the STEM education community.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202041PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6126828PMC
February 2019

Can pathological reports of rectal cancer provide national quality indicators?

ANZ J Surg 2018 09 23;88(9):E639-E643. Epub 2018 Mar 23.

Department of Surgery, The University of Auckland, Auckland, New Zealand.

Background: Rectal cancer care has become increasingly complex and requires accurate information. The pathology report is a vital tool for accessing information to gauge a patient's prognosis and to guide treatment decisions. The aim of this study was to assess the quality of histopathological reporting and surgery for rectal cancer in New Zealand using defined quality indicators.

Methods: This is a retrospective audit of pathological reports of all resected rectal cancer pathology reports submitted to the New Zealand Cancer Registry (NZCR) in 2015. The quality of reporting was assessed using specified criteria: synoptic report, adequate lymph node retrieval, reporting of circumferential resection margin (CRM) and mesorectal excision quality. Surgical outcomes were sphincter preservation rate, CRM clearance and complete mesorectal excision.

Results: A total of 803 patients with rectal cancer were reported to the NZCR in 2015, 505 underwent proctectomy. A total of 89.5% of reports were structured, 81.8% reported mesorectal excision quality and 86.7% reported CRM status. Adequate lymph node retrieval was obtained in 65.1%, complete mesorectal excision in 84.6% and positive CRM in 6.2% of cases. Quality varied between laboratories and district health boards. High-volume laboratories had higher quality reporting. Surgeon volume and training was related to adequate lymph node retrieval but not CRM clearance nor mesorectal excision quality.

Conclusion: High-quality pathological reporting is associated with the use of synoptic reporting templates. Surgical outcomes for rectal cancer in New Zealand, especially the low rate of CRM involvement, compare favourably with international audits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ans.14440DOI Listing
September 2018

The "rectosigmoid brake": Review of an emerging neuromodulation target for colorectal functional disorders.

Clin Exp Pharmacol Physiol 2017 Jul;44(7):719-728

Department of Surgery, University of Auckland, Auckland, New Zealand.

The regulation of gastrointestinal motility encompasses several overlapping mechanisms including highly regulated and coordinated neurohormonal circuits. Various feedback mechanisms or "brakes" have been proposed. While duodenal, jejunal, and ileal brakes are well described, a putative distal colonic brake is less well defined. Despite the high prevalence of colonic motility disorders, there is little knowledge of colonic motility owing to difficulties with organ access and technical difficulties in recording detailed motor patterns along its entire length. The motility of the colon is not under voluntary control. A wide range of motor patterns is seen, with long intervals of intestinal quiescence between them. In addition, the use of traditional manometric catheters to record contractile activity of the colon has been limited by the low number of widely spaced sensors, which has resulted in the misinterpretation of colonic motor patterns. The recent advent of high-resolution (HR) manometry is revolutionising the understanding of gastrointestinal motor patterns. It has now been observed that the most common motor patterns in the colon are repetitive two to six cycles per minute (cpm) propagating events in the distal colon. These motor patterns are prominent soon after a meal, originate most frequently in the rectosigmoid region, and travel in the retrograde direction. The distal prominence and the origin of these motor patterns raise the possibility of them serving as a braking mechanism, or the "rectosigmoid brake," to limit rectal filling. This review aims to describe what is known about the "rectosigmoid brake," including its physiological and clinical significance and potential therapeutic applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1440-1681.12760DOI Listing
July 2017

High-resolution anatomic correlation of cyclic motor patterns in the human colon: Evidence of a rectosigmoid brake.

Am J Physiol Gastrointest Liver Physiol 2017 May 23;312(5):G508-G515. Epub 2017 Mar 23.

Department of Surgery, University of Auckland, Auckland, New Zealand;

Colonic cyclic motor patterns (CMPs) have been hypothesized to act as a brake to limit rectal filling. However, the spatiotemporal profile of CMPs, including anatomic origins and distributions, remains unclear. This study characterized colonic CMPs using high-resolution (HR) manometry (72 sensors, 1-cm resolution) and their relationship with proximal antegrade propagating events. Nine healthy volunteers were recruited. Recordings were performed over 4 h, with a 700-kcal meal given after 2 h. Propagating events were visually identified and analyzed by pattern, origin, amplitude, extent of propagation, velocity, and duration. Manometric data were normalized using anatomic landmarks identified on abdominal radiographs. These were mapped over a three-dimensional anatomic model. CMPs comprised a majority of detected propagating events. Most occurred postprandially and were retrograde propagating events (84.9 ± 26.0 retrograde vs. 14.3 ± 11.8 antegrade events/2 h, = 0.004). The dominant sites of initiation for retrograde CMPs were in the rectosigmoid region, with patterns proximally propagating by a mean distance of 12.4 ± 0.3 cm. There were significant differences in the characteristics of CMPs depending on the direction of travel and site of initiation. Association analysis showed that proximal antegrade propagating events occurred independently of CMPs. This study accurately characterized CMPs with anatomic correlation. CMPs were unlikely to be triggered by proximal antegrade propagating events in our study context. However, the distal origin and prominence of retrograde CMPs could still act as a mechanism to limit rectal filling and support the theory of a "rectosigmoid brake." Retrograde cyclic motor patterns (CMPs) are the dominant motor patterns in a healthy prepared human colon. The major sites of initiation are in the rectosigmoid region, with retrograde propagation, supporting the idea of a "rectosigmoid brake." A significant increase in the number of CMPs is seen after a meal. In our study context, the majority of CMPs occurred independent of proximal propagating events, suggesting that CMPs are primarily controlled by external innervation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajpgi.00021.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451563PMC
May 2017

Effects of local vanadium delivery on diabetic fracture healing.

J Orthop Res 2017 10 8;35(10):2174-2180. Epub 2017 Mar 8.

Department of Orthopaedics, Rutgers New Jersey Medical School, 90 Bergen Street, Suite 7300, Newark, New Jersey 07101.

This study evaluated the effect of local vanadyl acetylacetonate (VAC), an insulin mimetic agent, upon the early and late parameters of fracture healing in rats using a standard femur fracture model. Mechanical testing, and radiographic scoring were performed, as well as histomorphometry, including percent bone, percent cartilage, and osteoclast numbers. Fractures treated with local 1.5 mg/kg VAC possessed significantly increased mechanical properties compared to controls at 6 weeks post-fracture, including increased torque to failure (15%; p = 0.046), shear modulus (89%; p = 0.043), and shear stress (81%; p = 0.009). The radiographic scoring analysis showed increased cortical bridging at 4 weeks and 6 weeks (119%; p = 0.036 and 209%; p = 0.002) in 1.5 mg/kg VAC treated groups. Histomorphometry of the fracture callus at days 10 and 14 showed increased percent cartilage (121%; p = 0.009 and 45%; p = 0.035) and percent mineralized tissue (66%; p = 0.035 and 58%; p = 0.006) with local VAC treated groups compared to control. Additionally, fewer osteoclasts were observed in the local VAC treated animals as compared to controls at day 14 (0.45% ± 0.29% vs. 0.83% ± 0.36% of callus area; p = 0.032). The results suggest local administration of VAC acts to modulate osteoclast activity and increase percentage of early callus cartilage, ultimately enhancing mechanical properties comparably to non-diabetic animals treated with local VAC. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2174-2180, 2017.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jor.23521DOI Listing
October 2017

Long-Term Training with a Brain-Machine Interface-Based Gait Protocol Induces Partial Neurological Recovery in Paraplegic Patients.

Sci Rep 2016 08 11;6:30383. Epub 2016 Aug 11.

Neurorehabilitation Laboratory, Associação Alberto Santos Dumont para Apoio à Pesquisa (AASDAP), Sâo Paulo, Brazil.

Brain-machine interfaces (BMIs) provide a new assistive strategy aimed at restoring mobility in severely paralyzed patients. Yet, no study in animals or in human subjects has indicated that long-term BMI training could induce any type of clinical recovery. Eight chronic (3-13 years) spinal cord injury (SCI) paraplegics were subjected to long-term training (12 months) with a multi-stage BMI-based gait neurorehabilitation paradigm aimed at restoring locomotion. This paradigm combined intense immersive virtual reality training, enriched visual-tactile feedback, and walking with two EEG-controlled robotic actuators, including a custom-designed lower limb exoskeleton capable of delivering tactile feedback to subjects. Following 12 months of training with this paradigm, all eight patients experienced neurological improvements in somatic sensation (pain localization, fine/crude touch, and proprioceptive sensing) in multiple dermatomes. Patients also regained voluntary motor control in key muscles below the SCI level, as measured by EMGs, resulting in marked improvement in their walking index. As a result, 50% of these patients were upgraded to an incomplete paraplegia classification. Neurological recovery was paralleled by the reemergence of lower limb motor imagery at cortical level. We hypothesize that this unprecedented neurological recovery results from both cortical and spinal cord plasticity triggered by long-term BMI usage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep30383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4980986PMC
August 2016

Dynamic Article: Full-Thickness Excision for Benign Colon Polyps Using Combined Endoscopic Laparoscopic Surgery.

Dis Colon Rectum 2016 Jan;59(1):16-21

1 Division of Colorectal Surgery, Department of Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York 2 Department of Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York 3 Division of Colorectal Surgery, Department of Surgery, University of Southern California, Keck School of Medicine, Los Angeles, California.

Background: Benign colon polyps are commonly encountered but may not always be amenable to endoscopic excision because of their size, shape, location, or scarring from previous attempts. The addition of laparoscopy allows a greater degree of bowel manipulation, but the current technique is still limited when encountering a polyp with inadequate lifting attributed to polyp morphology or scarring. We describe an extension to the existing combined endoscopic laparoscopic surgery technique using a full-thickness approach to increase polyp maneuverability and local excision of difficult but benign polyps.

Objective: The purpose of this study was to report the technical details and preliminary results of a new approach for full-thickness excision of difficult colon polyps, combined endoscopic laparoscopic surgery full-thickness excision.

Design: This study is a retrospective review of our experience from December 2013 to May 2015.

Settings: The study was conducted at a single academic institution.

Patients: All of the patients had previous incomplete colonoscopic polypectomy performed at other institutions. Patients were selected for our technique if the polyp had a benign appearance but was unable to be resected by traditional endoscopic or combined endoscopic laparoscopic surgery methods because of polyp morphology or scarring from previous biopsies.

Main Outcome Measures: The safety and feasibility of this procedure were measured.

Results: Three patients underwent combined endoscopic laparoscopic surgery-full-thickness excision for difficult colon polyps. There were no intraoperative or postoperative complications. The length of stay was 1 day for all of the patients. All 3 of the patients had benign final pathology.

Limitations: This study was limited by the small number of patients in a single institution.

Conclusions: Full-thickness excision for benign colon polyps using combined endoscopic laparoscopic surgery is safe and feasible. Using this technique, difficult polyps not amenable to traditional endoscopic approaches can be removed and colectomy may be avoided.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/DCR.0000000000000472DOI Listing
January 2016

Risk stratification of patients undergoing pulmonary metastasectomy for soft tissue and bone sarcomas.

J Thorac Cardiovasc Surg 2015 Jan 18;149(1):85-92. Epub 2014 Sep 18.

Division of Thoracic Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, Calif. Electronic address:

Objectives: Our objective was to identify risk factors associated with survival in patients who underwent pulmonary metastasectomy for soft tissue or bone sarcoma and to create a risk stratification model.

Methods: A retrospective review of the prospectively maintained University of California Los Angeles Sarcoma Database was performed. Clinical, pathologic, and treatment variables were analyzed for overall survival and disease-free survival. Univariate and multivariate analyses were performed, and variables that were identified as significant were included to create a risk model. A total of 155 patients who underwent pulmonary metastasectomy for soft tissue sarcoma (n = 108 patients) or bone sarcoma (n = 47 patients) from 1994 to 2010 were identified.

Results: Multivariate analysis identified 7 factors associated with poor overall survival: age more than 45 years, disease-free interval less than 1 year, thoracotomy, synchronous disease, location and type of sarcoma (soft tissue vs bone sarcoma), and performance of a lobectomy. The number of factors present was associated with poor overall survival, which varied widely from 64% in patients with 2 factors to 3% in those with 5 factors.

Conclusions: We have identified prognostic variables associated with overall survival after lung metastasectomy. Our model may be used as a risk stratification model to guide treatment decisions on the basis of the number of risk factors present. Although prospective studies are warranted to determine the benefit of surgical intervention in all cohorts compared with other local therapies or medical therapy, given the attendant dismal prognosis in patients with 5 or more risk factors, the benefit of surgical resection in this group is questioned.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jtcvs.2014.09.039DOI Listing
January 2015

Oct4 is required ~E7.5 for proliferation in the primitive streak.

PLoS Genet 2013 Nov 14;9(11):e1003957. Epub 2013 Nov 14.

Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.

Oct4 is a widely recognized pluripotency factor as it maintains Embryonic Stem (ES) cells in a pluripotent state, and, in vivo, prevents the inner cell mass (ICM) in murine embryos from differentiating into trophectoderm. However, its function in somatic tissue after this developmental stage is not well characterized. Using a tamoxifen-inducible Cre recombinase and floxed alleles of Oct4, we investigated the effect of depleting Oct4 in mouse embryos between the pre-streak and headfold stages, ~E6.0-E8.0, when Oct4 is found in dynamic patterns throughout the embryonic compartment of the mouse egg cylinder. We found that depletion of Oct4 ~E7.5 resulted in a severe phenotype, comprised of craniorachischisis, random heart tube orientation, failed turning, defective somitogenesis and posterior truncation. Unlike in ES cells, depletion of the pluripotency factors Sox2 and Oct4 after E7.0 does not phenocopy, suggesting that ~E7.5 Oct4 is required within a network that is altered relative to the pluripotency network. Oct4 is not required in extraembryonic tissue for these processes, but is required to maintain cell viability in the embryo and normal proliferation within the primitive streak. Impaired expansion of the primitive streak occurs coincident with Oct4 depletion ∼E7.5 and precedes deficient convergent extension which contributes to several aspects of the phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pgen.1003957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3828132PMC
November 2013

Missing consent forms in the preoperative area: a single-center assessment of the scope of the problem and its downstream effects.

JAMA Surg 2013 Sep;148(9):886-9

Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Missing consent forms at surgery can lead to delays in patient care, provider frustration, and patient anxiety. We sought to assess the scope and magnitude of this problem at our institution. We surveyed key informants to determine the frequency and effect of missing consent forms. We found that 66% of patients were missing signed consent forms at surgery and that this caused a delay for 14% of operative cases. In many instances, the missing consent forms interfered with team rounds and resident educational activities. In addition, residents spent less time obtaining consent and were often uncomfortable obtaining consent for major procedures. Finally, 40% of faculty felt dissatisfied with resident consent forms, and more than two-thirds felt patients were uncomfortable with being asked for consent by residents. At our center, missing consent forms led to delayed cases, burdensome and inadequate consent by residents, and extra work for nursing staff.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1001/jamasurg.2013.354DOI Listing
September 2013

Comparison of kidney-ureter-bladder abdominal radiography and computed tomography scout films for identifying renal calculi.

BJU Int 2009 Sep;104(5):670-3

Department of Urology, Christchurch Public Hospital, Christchurch, New Zealand.

Objective: To assess the sensitivity of computed tomography (CT) scout topograms and kidney-ureter-bladder abdominal radiography (KUB) in detecting urinary tract stones.

Patients And Methods: We assessed films taken on presentation for 163 consecutive patients referred to our service for stone follow-up. Only those with both CT and KUB imaging on the same day were studied further. Two urology registrars examined the films independently. Location, size and length of stone were recorded. Where there was discordance, the films were examined by an independent radiologist.

Results: In all, 108 of 163 patients had both CT and KUB imaging on the same day. Stones were identified in 63% (68/108) of patients with KUB, with a mean length of 4.93 mm. There were 40/108 radiolucent stones subsequently measured on CT, with a mean length of 4.90 mm. Stones were seen on 47% (51/108) of the CT scouts, with a mean length of 5.22 mm. Importantly, all stones visible on CT scout were also visible on KUB. There was no correlation between stone location and visibility on KUB or CT scout films.

Conclusion: KUB could be used for follow-up in 63% of cases. All stones seen on CT scout were also visible on KUB. Scout detected 75% of stones visible on KUB. We suggest CT scout film should be reported before proceeding to KUB. If the stone is visible on CT scout film, then the decision to use KUB for follow-up can be made. This minimizes radiation exposure and other costs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1464-410X.2009.08542.xDOI Listing
September 2009

Anaesthesia and analgesia: contribution to surgery, present and future.

ANZ J Surg 2008 Jul;78(7):540-7

Department of Anaesthesia, Christchurch School of Medicine, University of Otago, Christchurch, New Zealand.

Anaesthetists provide comprehensive perioperative medical care to patients undergoing surgical and diagnostic procedures, including postoperative intensive care when needed. They are involved in the management of perioperative acute pain as well as chronic pain. This manuscript considers some of the recent advances in modern anaesthesia and their contribution to surgery, from the basic mechanisms of action, to the delivery systems for general and regional anaesthesia, to the use of new drugs and new methods of monitoring. It assesses the resulting progress in acute and chronic pain services and looks at patient safety and risk management. It speculates on directions that may shape its future contributions to the management of the patient undergoing surgery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1445-2197.2008.04568.xDOI Listing
July 2008

Cholecystectomy following acute presentation to a major New Zealand metropolitan hospital: change to the timing of surgery is needed.

N Z Med J 2006 Aug 4;119(1239):U2104. Epub 2006 Aug 4.

Christchurch School of Medicine and Health Sciences, University of Otago.

Aims: To review the management and outcome of patients presenting with acute biliary pain/cholecystitis, mild acute pancreatitis, or cholangitis to a major New Zealand (NZ) metropolitan hospital.

Methods: A retrospective case note review was performed for all patients admitted acutely to Christchurch Public Hospital between 1 February 2005 and 31 September 2005, with the diagnosis of acute biliary pain/acute cholecystitis, acute pancreatitis, or cholangitis. Basic demographics, inpatient management, and subsequent outcome were recorded.

Results: Sixty-eight (65%) patients were admitted with acute biliary pain/cholecystitis, 23 (22%) with mild acute pancreatitis, and 13 (13%) with cholangitis. Twelve of 81 (15%) patients (who were suitable for index cholecystectomy) underwent surgery, including only 3 of the 18 patients with mild acute pancreatitis. In the remaining 69 (85%) patients, who were eligible but did not undergo cholecystectomy at the index admission, 29 (42%) subsequently represented to the emergency department. Forty-eight (70%) patients required further inpatient admission related to gallstone-related pathology within the study period. Subsequently, 42 (61%) of the 69 patients treated conservatively underwent cholecystectomy at a median (range) of 70 (1-195) days from index admission, including 6 emergency cholecystectomies due to re-presentation

Conclusions: The management of acute gallstone-related disease at a major NZ metropolitan hospital fails to meet with current international standards. Few patients undergo index cholecystectomy, and a large proportion of those treated conservatively return to the health sector with ongoing problems.
View Article and Find Full Text PDF

Download full-text PDF

Source
August 2006