Publications by authors named "Christian Schroeder"

Article Synopsis
  • Myelomeningocele (MMC) primarily impacts low-resource regions, especially where there is no mandatory folic acid fortification, but research on its neurosurgical management is concentrated in high-income countries (HICs).
  • A systematic review revealed that while HICs account for a small percentage of global neural tube defect cases, they dominate both authorship and patient representation in the research literature, with minimal contributions from lower-income countries.
  • Findings suggest a significant disparity in MMC research output relative to disease burden, highlighting an urgent need for increased scholarly attention and resource allocation in lower-income countries where MMC cases are more prevalent.
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Background: The authors report on a patient who presented with an extremely large presacral schwannoma and subsequent mass effect-induced hydronephrosis and kidney failure. To the authors' knowledge, this case represents the largest radiographically verified spinal schwannoma in the medical literature. The tumor presented here was more than three times as large as a typical giant schwannoma.

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For many spine surgeons, patients with metastatic cancer are often present in an emergent situation with rapidly progressive neurological dysfunction. Since the Patchell trial, scoring systems such as NOMS and SINS have emerged to guide the extent of surgical excision and fusion in the context of chemotherapy and radiation therapy. Yet, while multidisciplinary decision-making is the gold standard of cancer care, in the middle of the night, when a patient needs spinal surgery, the wealth of chemotherapy data, clinical trials, and other medical advances can feel overwhelming.

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Article Synopsis
  • The study investigates how effectively neurosurgical prenatal counseling (nPNC) is provided to families considering myelomeningocele (MMC) repair, focusing on the timing and factors influencing decisions on prenatal versus postnatal treatment.
  • Results show that 97% of families accessed nPNC, with 82% of consultations occurring before 24 weeks gestational age, and a significant number faced exclusions from fetal repair.
  • Most families ultimately chose between fetal repair, postnatal repair, or termination, with the main reasons for declining fetal repair being perceived risks and costs.
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Objective: Contemporary management of sacral chordomas requires maximizing the potential for recurrence-free and overall survival while minimizing treatment morbidity. En bloc resection can be performed at various levels of the sacrum, with tumor location and volume ultimately dictating the necessary extent of resection and subsequent tissue reconstruction. Because tumor resection involving the upper sacrum may be quite destabilizing, other pertinent considerations relate to instrumentation and subsequent tissue reconstruction.

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Animal models have been commonly used in immunotherapy research to study the cell response to external agents and to assess the effectiveness and safety of new therapies. Over the past few decades, immunocompromised (also called immunodeficient) mice allowed researchers to grow human tumor cells without the impact of the host's immune system. However, while this model is very valuable to understand the tumor biology and to understand the underlying mechanism of immunotherapy, the results may not always directly translate to humans.

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Background: Our objective is to describe a minimally invasive endoscopic surgical technique for performing lateral lumbar interbody fusion (LLIF). LLIF is a common approach to lumbar fusion in cases of degenerative lumbar disease; however, complications associated with psoas and lumbar plexus injury sometimes arise. The endoscopic modification presented here diminishes the requirement for sustained muscle retraction, minimizing complication risk while allowing for adequate decompression in select cases.

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During the COVID-19 pandemic, there was an increase in several risk factors for child maltreatment. There was also a sudden decrease in the systems available to identify and support at risk children and families. This study aims to describe the number of children presenting to specialized medical care for suspected child abuse and neglect during the first seven months of the COVID-19 pandemic compared to the three previous years.

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Introduction: Despite encouraging advances in radiation and surgical treatment, chordomas remain resistant to chemotherapy and local recurrence is common. Although the primary mechanism of recurrence is local, metastatic disease occurs in a small subset of patients. Recurrence may also occur along the surgical trajectory if care is not taken to fully excise the open biopsy pathway.

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Abusive head trauma (AHT) is a significant cause of morbidity and mortality for infants. Determining when to pursue a complete physical abuse evaluation can be difficult, especially for nonspecific findings or when a child appears clinically well. This retrospective study of 7 cases sought to describe the presentation, evaluation, and diagnoses for infants with abnormal subdural collections identified on cranial ultrasound for macrocephaly, and to determine how frequently AHT is diagnosed.

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Using an extensive database of every resident death in Virginia from 2005 to 2020, climate-mortality relationships are examined for 12 climatically homogeneous regions within the Commonwealth. Each region is represented by a first-order weather station from which archived temperature and humidity data are used to generate a variety of biometeorologically relevant indices. Using these indices and other variables (such as air quality and heat and cold waves), daily mortality and climate relationships are modeled for each region over a 21-day lag period utilizing generalized additive models and distributed lag non-linear models.

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Objective: Anogenital herpes simplex virus (HSV) is most commonly acquired via sexual transmission, although other nonsexual modes of transmission have been proposed. When a child presents with a first-time outbreak of anogenital HSV, providers must consider sexual abuse. There are currently no evidence-based consensus guidelines to inform management of these patients.

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Deboronation treatment of zeolite B-SSZ-55 can generate vacancy defects consisting of four silanol groups (silanol nests). However, H solid-state NMR spectroscopy indicates the prevalence of two silanol groups (silanol dyads) instead of four silanol groups. Such silanol dyads must be formed by the silanol condensation of two silanol groups at the silanol nests.

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Lymphatic congestion in single-ventricle patients has been associated with increased morbidity and poor outcomes. Little is known about the dynamics of lymphatic abnormalities over time, on their association with clinical presentation or response to catheter interventions. This retrospective, single-center study describes Fontan patients who underwent at least two magnetic resonance imaging (MRI) studies.

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Objectives: Complications after Fontan surgery have been associated with arise and classification of abnormal thoracic lymphatic perfusion pattern. This study compiles abnormal abdominal lymphatic perfusion patterns and investigates their impact on serum protein readings.

Methods: We performed a retrospective analysis of patients who underwent magnetic resonance imaging with T2-weighted lymphatic imaging and serum protein measurements 6 months after having Fontan surgery.

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Reliable laboratory parameters identifying complications after Fontan surgery including the lymphatic abnormalities and the development of protein-losing enteropathy (PLE) are rare. Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocte ratio (PLR) are inflammatory markers and have been studied to predict outcome and prognosis in various diseases. The aim of this study was to investigate NLR and PLR from birth to follow-up after Fontan and evaluate their use as prognostic parameters for single ventricle patients regarding the development of lymphatic malformations during follow-up.

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The zeolite catalyst SSZ-42 shows a remarkable high abundance (≈80 %) of hydrogen-bonded Brønsted acid sites (BAS), which are deshielded from the H chemical shift of unperturbed BAS at typically 4 ppm. This is due to their interaction with neighboring oxygen atoms in the zeolite framework when oxygen alignments are suitable. The classification and diversity of hydrogen bonding is assessed by DFT calculations, showing that oval-shaped 6-rings and 5-rings allow for a stronger hydrogen bond to oxygen atoms on the opposite ring side, yielding higher experimental chemical shifts (δ ( H)=6.

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Article Synopsis
  • - The study explores how a specific molecule interacts with a pore mouth, focusing on a calix[4]arene-Ti complex that's attached to the surface of a zeotype material.
  • - Using techniques like X-ray absorption and NMR spectroscopy, researchers observed a unique shape of this complex when it was located at precise spots between microporous cavities and the external surface.
  • - Computational analysis indicates that this unique shape is caused by the optimal arrangement of the molecule, which enhances its interactions with the cavity walls, providing insights into how environmental conditions influence molecular confinement and adsorption.
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Nests of three silanol groups are located on the internal pore surface of calcined zeolite SSZ-70. 2D H double/triple-quantum single-quantum correlation NMR experiments enable a rigorous identification of these silanol triad nests. They reveal a close proximity to the structure directing agent (SDA), that is, N,N'-diisobutyl imidazolium cations, in the as-synthesized material, in which the defects are negatively charged (silanol dyad plus one charged SiO siloxy group) for charge balance.

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Ischemic stroke is a leading cause of death worldwide and clinical data suggest that children may recover from stroke better than adults; however, supporting experimental data are lacking. We used our novel mouse model of experimental juvenile ischemic stroke (MCAO) to characterize age-specific cognitive dysfunction following ischemia. Juvenile and adult mice subjected to 45-min MCAO, and extracellular field recordings of CA1 neurons were performed to assess hippocampal synaptic plasticity changes after MCAO, and contextual fear conditioning was performed to evaluate memory and biochemistry used to analyze Nogo-A expression.

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Two pairs of Brønsted acid sites have been identified in H,Na-Y zeolite, located in the supercage and in the sodalite cage, which upon ultrastabilization (dealumination) are transformed into pairs of Brønsted and Lewis acid sites. This mild postsynthetic modification step is an important process for converting this material into an active catalyst for large-scale commercial reactions. Pairing structures and their transformations have been investigated using H double-quantum NMR spectroscopy experiments for dehydrated zeolite, H,Na-Y, and its ultrastabilized form, H,Na-USY.

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The effect of outer-sphere environment on alkene epoxidation catalysis using an organic hydroperoxide oxidant is demonstrated for calix[4]arene-Ti single-sites grafted on amorphous vs crystalline delaminated zeotype (UCB-4) silicates as supports. A chelating calix[4]arene macrocyclic ligand helps enforce a constant Ti inner-sphere, as characterized by UV-visible and X-ray absorption spectroscopies, thus enabling the rigorous comparison of outer-sphere environments across different siliceous supports. These outer-sphere environments are characterized by solid-state H NMR spectroscopy to comprise proximally organized silanols confined within 12 membered-ring cups in crystalline UCB-4, and are responsible for up to 5-fold enhancements in rates of epoxidation by Ti centers.

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The current study focuses on the ability to improve cognitive function after stroke with interventions administered at delayed/chronic time points. In light of recent studies demonstrating delayed GABA antagonists improve motor function, we utilized electrophysiology, biochemistry and neurobehavioral methods to investigate the role of α5 GABAA receptors on hippocampal plasticity and functional recovery following ischemic stroke. Male C57Bl/6 mice were exposed to 45 min transient middle cerebral artery occlusion and analysis of synaptic and functional deficits performed 7 or 30 days after recovery.

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The objective of our study was to evaluate the impact of the tibial keel & stem length in surface cementation, of a full cemented keel and of an additional tibial stem on the primary stability of a posterior stabilised tibial plateau (VEGA® System Aesculap Tuttlingen, Germany) under dynamic compression-shear loading conditions in human tibiae. We performed the cemented tibial plateau implantations on 24 fresh-frozen human tibiae of a mean donor age of 70.7years (range 47-97).

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Cardiac arrest and cardiopulmonary resuscitation (CA/CPR) produce brain ischemia that results in cognitive and motor coordination impairments subsequent to injury of vulnerable populations of neurons, including cerebellar Purkinje neurons. To determine the effects of CA/CPR on plasticity in the cerebellum, we used whole cell recordings from Purkinje neurons to examine long-term depression (LTD) at parallel fiber (PF) synapses. Acute slices were prepared from adult male mice subjected to 8 min cardiac arrest at 1, 7, and 30 days after resuscitation.

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