Publications by authors named "N M Ung"

91 Publications

SARS-CoV-2 Infection and COVID-19 Outcomes in Rheumatic Disease: A Systematic Literature Review And Meta-Analysis.

Arthritis Rheumatol 2021 Nov 22. Epub 2021 Nov 22.

Campbelltown Hospital, Campbelltown, New South Wales, Australia and University of Western Sydney, New South Wales, Australia.

Objective: The relative risk of SARS-CoV-2 infection and COVID-19 disease severity among people with rheumatic and musculoskeletal diseases (RMD) compared to those without RMD remains uncertain. We sought to quantify the risk for SARS-CoV-2 infection and describe clinical outcomes of COVID-19 in people with RMD.

Methods: A systematic literature review was conducted using 14 databases from January 1 , 2019 to February 13 , 2021. We included observational studies and experimental trials in RMD patients reporting comparative rates of SARS-CoV-2 infection, hospitalization, oxygen supplementation/ICU admission/mechanical ventilation, or mortality attributed to COVID-19. Methodological quality was evaluated using the Joanna Briggs Institute Critical Appraisal Tools or the Newcastle-Ottawa scale. Risk ratios (RRs) and odds ratios (ORs) were calculated, as applicable for each outcome, using the Mantel-Haenszel formula with random effect models.

Results: Of 5799 abstracts screened, 100 studies met criteria for inclusion in the systematic review and 54/100 had a low risk-of-bias. Among studies included in the meta-analyses, we found an increased prevalence of SARS-CoV-2 infection in people with RMD (RR 1.53 (95%CI 1.16, 2.01)) compared with the general population. Odds of hospitalization, ICU admission, and mechanical ventilation were similar in patients with and without RMD, whereas odds of mortality was increased (OR 1.74 (95%CI 1.08, 2.80)). A smaller number of studies reported adjusted risk for outcomes and variably demonstrated increased risk for no difference in risk.

Conclusion: Patients with RMDs had higher rates of SARS-CoV-2 infection and increased odds of mortality. This article is protected by copyright. All rights reserved.
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http://dx.doi.org/10.1002/art.42030DOI Listing
November 2021

Accuracy and outcomes of diffusion tensor imaging tractography in resection for vestibular schwannoma for facial nerve preservation.

J Neurol Sci 2021 Nov 25;430:120006. Epub 2021 Sep 25.

Departments of Neurosurgery, United States of America; Office of the Patient Experience, United States of America; Radiation Oncology, Head and Neck Surgery, United States of America; UCLA Jonsson Comprehensive Cancer Center, Ronald Reagan, United States of America; UCLA Medical Center, Los Angeles, CA, United States of America; Department of Neurosurgery and the Los Angeles, United States of America; Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA, United States of America. Electronic address:

Background: Impairment of facial nerve (FN) function is a common postoperative complication in surgical resections of Vestibular Schwannomas (VS). Diffusion tensor imaging (DTI) tractography creates in vivo imaging of the anatomical location of white matter tracts that can be preoperatively used to visualize the displaced FN. We present an analysis of patients who underwent DTI tractography imaging prior to VS resection.

Methods: Patient charts were reviewed from March 2012 to April 2015 who underwent DTI tractography prior to surgical resection for VS. Reliability of this measure was compared to the intraoperative FN location as determined by the surgeon. House Brackmann (HB) score was used to assess facial nerve function.

Results: A total of 11 patients were included with a mean age of 43 years (range: 19-64) and mean follow-up length of 11.9 months (range: 3.1-34.2). The average maximum tumor diameter was 2.82 cm (range: 1.7-4.2). DTI tractography was accurate in 90.9% (10/11) of patients. Postoperatively, 72.7% (8/11) had a HB score of I or II, 18.2% (2/11) had a HB score of III, and 9.1% (1/11) had a HB score of IV.

Conclusions: Facial nerve visualization for VS resection can be accurately visualized using DTI tractography. This modality may lead to reduction of postoperative FN damage.
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http://dx.doi.org/10.1016/j.jns.2021.120006DOI Listing
November 2021

An international survey of imaging practices in radiotherapy.

Phys Med 2021 Oct 22;90:53-65. Epub 2021 Sep 22.

The National Center for Applied Physics, King Abdulaziz City for Science and Technology (KACST), P.O. Box: 6086, Riyadh, Saudi Arabia; Mentorship programme, International Commission on Radiological Protection, 280 Slater Street, Ottawa, Ontario K1P 5S9, Canada.

Improvements in delivery of radiation dose to target tissues in radiotherapy have increased the need for better image quality and led to a higher frequency of imaging patients. Imaging for treatment planning extends to function and motion assessment and devices are incorporated into medical linear accelerators (linacs) so that regions of tissue can be imaged at time of treatment delivery to ensure dose distributions are delivered as accurately as possible. A survey of imaging in 97 radiotherapy centres in nine countries on six continents has been undertaken with an on-line questionnaire administered through the International Commission on Radiological Protection mentorship programme to provide a snapshot of imaging practices. Responses show that all centres use CT for planning treatments and many utilise additional information from magnetic resonance imaging and positron emission tomography scans. Most centres have kV cone beam CT attached to at least some linacs and use this for the majority of treatment fractions. The imaging options available declined with the human development index (HDI) of the country, and the frequency of imaging during treatment depended more on country than treatment site with countries having lower HDIs imaging less frequently. The country with the lowest HDI had few kV imaging facilities and relied on MV planar imaging intermittently during treatment. Imaging protocols supplied by vendors are used in most centres and under half adapt exposure conditions to individual patients. Recording of patient doses, a knowledge of which is important in optimisation of imaging protocols, was limited primarily to European countries.
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http://dx.doi.org/10.1016/j.ejmp.2021.09.004DOI Listing
October 2021

Creation of a Single Cell RNASeq Meta-Atlas to Define Human Liver Immune Homeostasis.

Front Immunol 2021 16;12:679521. Epub 2021 Jul 16.

Division of Abdominal Organ Transplantation and Hepatobiliary Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.

The liver is unique in both its ability to maintain immune homeostasis and in its potential for immune tolerance following solid organ transplantation. Single-cell RNA sequencing (scRNA seq) is a powerful approach to generate highly dimensional transcriptome data to understand cellular phenotypes. However, when scRNA data is produced by different groups, with different data models, different standards, and samples processed in different ways, it can be challenging to draw meaningful conclusions from the aggregated data. The goal of this study was to establish a method to combine 'human liver' scRNA seq datasets by 1) characterizing the heterogeneity between studies and 2) using the meta-atlas to define the dominant phenotypes across immune cell subpopulations in healthy human liver. Publicly available scRNA seq data generated from liver samples obtained from a combined total of 17 patients and ~32,000 cells were analyzed. Liver-specific immune cells (CD45+) were extracted from each dataset, and immune cell subpopulations (myeloid cells, NK and T cells, plasma cells, and B cells) were examined using dimensionality reduction (UMAP), differential gene expression, and ingenuity pathway analysis. All datasets co-clustered, but cell proportions differed between studies. Gene expression correlation demonstrated similarity across all studies, and canonical pathways that differed between datasets were related to cell stress and oxidative phosphorylation rather than immune-related function. Next, a meta-atlas was generated data integration and compared against PBMC data to define gene signatures for each hepatic immune subpopulation. This analysis defined key features of hepatic immune homeostasis, with decreased expression across immunologic pathways and enhancement of pathways involved with cell death. This method for meta-analysis of scRNA seq data provides a novel approach to broadly define the features of human liver immune homeostasis. Specific pathways and cellular phenotypes described in this human liver immune meta-atlas provide a critical reference point for further study of immune mediated disease processes within the liver.
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http://dx.doi.org/10.3389/fimmu.2021.679521DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8322955PMC
October 2021
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