Publications by authors named "Peter Jun"

Background & Aim: Utilization of augmented reality (AR) and heads-up displays (HUD) to aid orthopaedic surgery has the potential to benefit surgeons and patients alike through improved accuracy, safety, and educational benefits. With the COVID-19 pandemic, the opportunity for adoption of novel technology is more relevant. The aims are to assess the technology available, to understand the current evidence regarding the benefit and to consider challenges to implementation in clinical practice.

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Objective: Spontaneous spinal cerebrospinal fluid (CSF) leaks are rare and challenging to diagnose and treat. Patients may present to a variety of physicians, and many patients are often referred to a specialized center with a dedicated spinal CSF leak program and expertise in this condition. To our knowledge, there are no reported publications on how to create such a program.

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Introduction: In individuals having low back pain, the application of spinal manipulative therapy (SMT) has been shown to reduce spinal stiffness in those who report improvements in post-SMT disability. The underlying mechanism for this rapid change in stiffness is not understood presently. As clinicians and patients may benefit from a better understanding of this mechanism in terms of optimizing care delivery, the objective of this scoping review of current literature was to identify if potential mechanisms that explain this clinical response have been previously described or could be elucidated from existing data.

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The tremendous cost, pain and disability associated with degenerative disc disease (DDD) makes the development of a biological agent that can mitigate the course of DDD, a critical unmet need. We have identified and reported that a single injection of a combination of recombinant human (rh) Transforming growth factor beta 1 (TGF-β1) and Connective tissue growth factor (CTGF) proteins into the injured intervertebral disc (IVD) nucleus pulposus (NP) can mediate DDD in a pre-clinical rodent model. In this study, we developed and evaluated the efficacy of a novel molecular therapy (NTG-101) containing rhTGF-β1 and rhCTGF proteins suspended in an excipient solution using in vivo models of DDD including rat-tail and chondrodystrophic (CD) canines.

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Quantifying three-dimensional upper body kinematics can be a valuable method for assessing upper limb function. Considering that kinematic model characteristics, performed tasks, and reported outcomes are not consistently standardized and exhibit significant variability across studies, the purpose of this review was to evaluate the literature investigating upper body kinematics in non-disabled individuals via optical motion capture. Specific objectives were to report on the kinematic model characteristics, performed functional tasks, and kinematic outcomes, and to assess whether kinematic protocols were assessed for validity and reliability.

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Objectives/hypothesis: The prevalence of multiglandular disease (MGD) of the parathyroid has been reported to be higher in patients with primary hyperparathyroidism and low baseline intact parathyroid hormone (PTH) levels (<100 pg/mL). Low baseline PTH is associated with lower localization rate and positive predictive value with both preoperative sestamibi and ultrasound. This study sought to evaluate our experience with four-dimensional computed tomography (4D-CT) for the localization of abnormal parathyroid glands, including MGD, in patients with low baseline intact PTH (LBiPTH).

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Objectives: Prior studies examining the sensitivity of cranial computed tomography (CT) for the detection of subarachnoid hemorrhage (SAH) have used the final radiology report as the reference standard. However, optimal sensitivity may have been underestimated due to misinterpretation of reportedly normal cranial CTs. This study aims to estimate the incidence of missed CT evidence of SAH among a cohort of patients with aneurysmal SAH (aSAH).

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Invasive facial fungal infections affect the orofacial soft tissues in immunocompromised patients and can cause significant morbidity and mortality. Primary infection occurs from direct inoculation of the skin surface, while secondary infection occurs from extension from an adjacent sinonasal process. The imaging features of secondary infection are similar to acute fulminant invasive fungal sinusitis with infiltration of the orofacial soft tissues in combination with sinonasal disease.

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Objective And Background: Spinal arteriovenous fistula (SAVF) is a rare but treatable cause of myelopathy. The diagnostic accuracy of MRI for detecting SAVF is unknown. Our objective was to determine the sensitivity and specificity of MRI in the diagnosis SAVF and characterize its radiographic features.

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Both genetic and epigenetic mechanisms contribute to meningioma development by altering gene expression and protein function. To determine the relative contribution of each mechanism to meningioma development, we used an integrative approach measuring copy number and DNA methylation changes genomewide. We found that genetic alterations affected 1.

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Background: Meningiomas are common brain tumors that are classified into three World Health Organization grades (benign, atypical and malignant) and are molecularly ill-defined tumors. The purpose of this study was identify molecular signatures unique to the different grades of meningiomas and to unravel underlying molecular mechanisms driving meningioma tumorigenesis.

Results: We have used a combination of gene expression microarrays and array comparative genomic hybridization (aCGH) to show that meningiomas of all three grades fall into two main molecular groups designated 'low-proliferative' and 'high-proliferative' meningiomas.

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Human cancer genome and epigenome projects aim to identify new cancer genes and targets for therapy that have been overlooked by conventional approaches. Here we integrated large-scale genomics and epigenomics of 31 human infiltrative gliomas and identified low-frequency deletion and highly recurrent epigenetic silencing of WNK2, encoding a putative serine/threonine kinase. Prior cancer genome sequencing projects also identified point mutations in WNK1-4, suggesting that WNK family genes may have a role in cancers.

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Objective: To introduce the supratonsillar approach, an approach that traverses the tonsillobiventral fissure in a trajectory over the cerebellar tonsil to the inferior cerebellar peduncle, and to demonstrate the utility of this approach for resecting peduncular cavernous malformations.

Methods: Anatomy of the cerebellar tonsil and surrounding fissures, arteries, and veins are reviewed using cadaveric brain specimens. The surgical approach uses the three-quarter prone position, a suboccipital craniotomy, and wide splitting of the tonsillobiventral fissure.

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Objective: The integration of digital image-guided surgical navigation with C-arm fluoroscopy, known as virtual fluoroscopy (VF), has been shown to enhance the safety of spine surgery in vitro. Few clinical studies have assessed the accuracy of VF during actual spinal surgery, and no studies have investigated variations in accuracy over the course of a series of measurements obtained during operative cases. We sought to study the intraoperative accuracy of VF over time and space during lumbar pedicle screw placement in human patients.

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Background: Airbag deployment is an acknowledged mechanism of serious trauma in children involved in motor vehicle crashes. From a review of national databases, we determined the number and types of fatal and nonfatal injuries to children caused by airbag deployment and child restraint system use. We also reviewed the relevant literature and provide information useful for caregivers and health care professionals in hopes of reducing future injuries.

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Meningiomas constitute the second most common central nervous system tumor, and yet relatively little is known about the molecular events that are important for the pathogenesis and malignant progression of these tumors. We have used serial analysis of gene expression to compare the transcriptomes of nonneoplastic meninges and meningiomas of all malignancy grades. A novel finding from this screen is the induction of three components of the Notch signaling pathway: the transcription factor, hairy and enhancer of Split1 (HES1) and two members of the Groucho/transducin-like enhancer of Split family of corepressors, TLE2 and TLE3.

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CpG islands are present in one-half of all human and mouse genes and typically overlap with promoters or exons. We developed a method for high-resolution analysis of the methylation status of CpG islands genome-wide, using arrays of BAC clones and the methylation-sensitive restriction enzyme NotI. Here we demonstrate the accuracy and specificity of the method.

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Tumors arise in part from the deleterious effects of genetic and epigenetic mechanisms on gene expression. In several mouse models of human tumors, the tumorigenic phenotype is reversible, suggesting that epigenetic mechanisms also contribute significantly to tumorigenesis in mice. It is not known whether these are the same epigenetic mechanisms in human and mouse tumors or whether they affect homologous genes.

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Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy in children and adults, with an incidence of 22,000 cases per year in the United States. Differentiating PTC from more frequently occurring benign thyroid nodules has proved challenging as there may be significant overlap in their clinical presentation and sonographic appearance. That said, high-resolution ultrasound provides a safe and affordable way of identifying and characterizing thyroid nodules and guiding percutaneous biopsies.

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Object: Infections along the spinal axis are characterized by an insidious onset, and the resulting delays in diagnosis are associated with serious neurological consequences and even death. Infections of the spine can affect the vertebral bodies, intervertebral discs, spinal canal, and surrounding soft tissues. Neurological dysfunction occurs when the spinal cord becomes compressed, edematous, or ischemic due to compression by abscess or vascular compromise.

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