Publications by authors named "Matthew Schultz"

Article Synopsis
  • The study investigates the molecular effects of legacy and replacement PFASs, specifically focusing on PFOS and its replacements, PFECHS and FBSA, in zebrafish embryos exposed to varying concentrations.
  • Results show that PFOS is the most toxic, indicating a significant risk associated with both legacy and newly introduced PFASs.
  • Findings suggest that the safety of replacement PFASs is questionable, prompting a need for reassessment of regulatory standards due to their emerging presence in the environment.
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Case: A 71-year-old man with a history of C5-7 anterior cervical discectomy and fusion (ACDF) sustained a C7 spinous process fracture after falling from a ladder. He was initially managed nonoperatively but developed anterolisthesis and kyphosis at C7-T1 with left hand weakness over the course of 11 days. Surgical treatment included spinous process wiring and C5-T3 posterior fusion.

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Transferrin isoform analysis is an established laboratory test for congenital disorders of glycosylation (CDG). Despite its long history of clinical use, little has been published about its empirical sensitivity for specific conditions. We conducted a retrospective analysis of ten years of testing data and report our experience with transferrin testing for type I profiles and its sensitivity for the most common congenital disorder of glycosylation, PMM2-CDG.

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Background: Sphingolipids play a crucial role in cellular functions and are essential components of cell membranes, signaling molecules, and lipid metabolism. In particular, ceramide is a key intermediate in sphingolipid metabolism and defects in ceramide metabolism can lead to various inborn errors of metabolism, making ceramides important targets for clinical screening and diagnosis. Detecting altered concentration patterns of sphingolipids is desirable for distinguishing related inborn errors of metabolism for diagnosis and treatment monitoring.

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The analysis of gangliosides and glycosphingolipids is crucial for understanding cellular membrane structure and function as well as to accurately diagnose certain inborn errors of metabolism. GM2-gangliosidosis represents a rare and fatal group of lysosomal storage disorders characterized by accumulation of GM2 gangliosides in various tissues and organs. These disorders arise due to deficiency or functional impairment of the β-hexosaminidase A or B enzymes, which are responsible for degradation of GM2 ganglioside.

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Treatment of phenylketonuria (PKU) has evolved since the initial introduction of a phenylalanine (Phe) restricted diet. The most recent option for adults affected with PKU is treatment with an alternate enzyme, phenylalanine ammonia lyase (PAL), that metabolizes excess Phe. Proper management of all patients with PKU relies on accurate measurement of Phe levels in blood, to comply with guidance intended to minimize the neurological symptoms.

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Article Synopsis
  • The study aimed to examine how resilience affects pain and neck disability outcomes in patients who had single- or double-level anterior cervical discectomy and fusion (ACDF).
  • Patients completed surveys on resilience, pain, and disability levels both before and after surgery, allowing researchers to categorize them based on their resilience levels.
  • Results showed that all patients improved post-surgery, but those with higher resilience reported better pain relief compared to those with lower resilience, indicating resilience may play a role in recovery outcomes.
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Article Synopsis
  • Diagnosis of PMM2-CDG, a common congenital disorder, traditionally involves carbohydrate-deficient transferrin testing and genetic analysis, but current tests can yield false negatives and might normalize as patients age.
  • In this study, researchers used advanced mass spectrometry to analyze serum samples from 72 patients, uncovering specific changes in N-glycoproteins that could indicate the disorder more accurately than current testing methods.
  • A notable finding was the presence of a unique glycopeptide from complement C4 in patients that had normal CDT results, suggesting it could serve as a more sensitive and reliable biomarker for diagnosing and monitoring PMM2-CDG.
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Creatine transporter deficiency has been described with normal or uninformative levels of creatine and creatinine in plasma, while urine has been the preferred specimen type for biochemical diagnosis. We report a cohort of untreated patients with creatine transporter deficiency and abnormal plasma creatine panel results, characterized mainly by markedly decreased plasma creatinine. We conclude that plasma should be considered a viable specimen type for the biochemical diagnosis of this disorder, and abnormal results should be followed up with further confirmatory testing.

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Background: Total joint arthroplasty (TJA) performed in the ambulatory surgical center (ASC) has been shown to be safe and cost-effective for an expanding cohort of patients. As criteria for TJA in the ASC become less restrictive, data guiding the efficient use of ASC resources are crucial.

Purpose: We sought to identify factors associated with length of stay in the recovery room after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) performed in the ASC.

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Purpose: In the absence of prospective data on neurological symptoms, disease outcome, or guidelines for system specific management in phosphomannomutase 2-congenital disorders of glycosylation (PMM2-CDG), we aimed to collect and review natural history data.

Methods: Fifty-one molecularly confirmed individuals with PMM2-CDG enrolled in the Frontiers of Congenital Disorders of Glycosylation natural history study were reviewed. In addition, we prospectively reviewed a smaller cohort of these individuals with PMM2-CDG on off-label acetazolamide treatment.

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The phosphatidylinositol glycan anchor biosynthesis class O protein (PIGO) enzyme is an important step in the biosynthesis of glycosylphosphatidylinositol (GPI), which is essential for the membrane anchoring of several proteins. Bi-allelic pathogenic variants in lead to a congenital disorder of glycosylation (CDG) characterized by global developmental delay, an increase in serum alkaline phosphatase levels, congenital anomalies including anorectal, genitourinary, and limb malformations in most patients; this phenotype has been alternately called "Mabry syndrome" or "hyperphosphatasia with impaired intellectual development syndrome 2." We report a 22-month-old female with PIGO deficiency caused by novel variants.

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Study Design: Retrospective cohort.

Objective: Investigate the relationship between preoperative benzodiazepine exposure and postoperative opioid use in patients undergoing primary 1 or 2-level anterior cervical discectomy and fusion (ACDF).

Background: Little is known about the effect of preoperative benzodiazepine exposure on postoperative opioid use in spine surgery.

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Abnormal polyol metabolism is predominantly associated with diabetes, where excess glucose is converted to sorbitol by aldose reductase (AR). Recently, abnormal polyol metabolism has been implicated in phosphomannomutase 2 congenital disorder of glycosylation (PMM2-CDG) and an AR inhibitor, epalrestat, proposed as a potential therapy. Considering that the PMM2 enzyme is not directly involved in polyol metabolism, the increased polyol production and epalrestat's therapeutic mechanism in PMM2-CDG remained elusive.

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Article Synopsis
  • PGM1-CDG is a rare genetic metabolic disorder caused by a deficiency of the PGM1 enzyme, leading to various health issues, including liver and cardiac problems, hypoglycemia, and muscle breakdown.
  • The treatment of this condition involves oral D-galactose (D-gal) supplementation, which has shown clinical improvement in several patients, although results can vary significantly.
  • Despite some successes with D-gal, challenges remain, particularly regarding cardiac function, highlighting the need for new therapeutic strategies to address this aspect of PGM1-CDG.
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In patients who undergo femoral fracture fixation with a cephalomedullary nail, the breakage of one or more of the distal interlocking screws is a well-described phenomenon. The presence of a broken interlocking screw in patients who require the removal of their cephalomedullary nail presents a unique challenge. The broken interlocking screw may be retrieved, or the screw may be retained if it is not engaged within the nail and the nail can safely be removed while leaving the broken screw fragment behind.

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ATP6AP1-CDG is an X-linked disorder typically characterized by hepatopathy, immunodeficiency, and an abnormal type II transferrin glycosylation pattern. Here, we present 11 new patients and clinical updates with biochemical characterization on one previously reported patient. We also document intrafamilial phenotypic variability and atypical presentations, expanding the symptomatology of ATP6AP1-CDG to include dystonia, hepatocellular carcinoma, and lysosomal abnormalities on hepatic histology.

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biotransformation assays with primary trout hepatocytes (RT-HEP) or liver subcellular fractions (RT-S9) have been proposed as valuable tools to help scientists and regulators better understand the toxicokinetics of chemicals. While both assays have been applied successfully to a diversity of neutral organic chemicals, only the RT-S9 assay has been applied to a large number of ionizable organic chemicals. Here, a combination of an biotransformation assay with RT-HEP with an active transport assay based on the permanent rainbow trout liver cell line RTL-W1 was used to qualitatively predict the potential hepatic clearance of nine psychotropic drugs with various degrees of ionization.

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Introduction: Plasma amino acids profiling can aid in the screening and diagnosis of aminoacidopathies. The goal of the current study was to analyze and report the metabolic profiles of plasma amino acid (PAA) and additionally to compare PAA-reference intervals (RI) from Pakistan with more countries utilizing Clinical Laboratory Integrated Reports (CLIR).

Methods: This was a cross sectional prospective single center study.

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Background: Some clinically important genetic variants are not easily evaluated with next-generation sequencing (NGS) methods due to technical challenges arising from high- similarity copies (e.g., PMS2, SMN1/SMN2, GBA1, HBA1/HBA2, CYP21A2), repetitive short sequences (e.

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biotransformation assays using hepatocytes or liver subcellular fractions, combined with extrapolation (IVIVE) models, have been proposed as an alternative to live fish bioconcentration studies. The uncertainty associated with IVIVE approaches to date has been attributed to assay protocols, model assumptions, or variability of data. An isolated perfused trout liver model that measures hepatic clearance has been proposed for validating IVIVE predictions in the absence of other confounding factors.

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Context: Opioids are commonly utilized for the treatment of chronic pain. However, research regarding the long-term (≥12 months) outcomes of opioid therapy remains sparse.

Objectives: This study aims to evaluate the effects of long-term opioid therapy on measures of back-specific disability and health-related quality of life in patients with chronic low back pain.

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Chromosomal microarray (CMA) is a testing modality frequently used in pediatric patients; however, published data on its utilization are limited to the genetic setting. We performed a database search for all CMA testing performed from 2010 to 2020, and delineated the diagnostic yield based on patient characteristics, including sex, age, clinical specialty of providers, indication of testing, and pathogenic finding. The indications for testing were further categorized into Human Phenotype Ontology categories for analysis.

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Case: A 29-year-old man presented with a displaced medial clavicle fracture. Surgical repair was performed using a precontoured plate designed for the contralateral distal clavicle, and medial fixation was accomplished at the sternum. The patient had no complications and demonstrated full strength and range of motion at the 8-month follow-up.

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