Publications by authors named "Koehler R"

Article Synopsis
  • * A review of surgeries at two different centers revealed that a majority of these patients (75.4%) develop post-operative fevers, but additional testing typically did not provide useful information.
  • * The research suggested that children managed under an accelerated discharge pathway had fewer PICU admissions and associated fever work-ups, indicating that such pathways could reduce unnecessary hospital stays and related complications.
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Background: How frequently out-of-hospital cardiac arrest (OHCA) occurs within a reasonable walking distance to the nearest public automated external defibrillator (AED) has not been well studied.

Methods: As Kansas City, Missouri has a comprehensive city-wide public AED registry, we identified adults with an OHCA in Kansas City during 2019-2022 in the Cardiac Arrest Registry to Enhance Survival. Using AED location data from the registry, we computed walking times between OHCAs and the nearest registered AED using the Haversine formula, a mapping algorithm to calculate walking distance in miles from one location to another.

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Background: The SPAN trial (Stroke Preclinical Assessment Network) is the largest preclinical study testing acute stroke interventions in experimental focal cerebral ischemia using endovascular filament middle cerebral artery occlusion (MCAo). Besides testing interventions against controls, the prospective design captured numerous biological and procedural variables, highlighting the enormous heterogeneity introduced by the multicenter structure that might influence stroke outcomes. Here, we leveraged the unprecedented sample size achieved by the SPAN trial and the prospective design to identify the biological and procedural variables that affect experimental stroke outcomes in transient endovascular filament MCAo.

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  • Diastolic blood pressure (DBP) is proposed as a reliable indicator of coronary perfusion pressure (CPP) during CPR, and this study analyzed their correlation with survival outcomes in a pediatric swine model of cardiac arrest.
  • The analysis of 102 pediatric swine resuscitations showed that both DBP and CPP were higher in survivors compared to non-survivors, especially after the first epinephrine dosage, with specific predictive thresholds identified for each measurement.
  • Findings suggest that monitoring DBP could be crucial during resuscitation efforts, as it closely reflects CPP and is associated with better survival rates, making it a practical target for enhancing the effectiveness of CPR.
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Clinical trials of hypothermia after pediatric cardiac arrest (CA) have not seen robust improvement in functional outcome, possibly because of the long delay in achieving target temperature. Previous work in infant piglets showed that high nasal airflow, which induces evaporative cooling in the nasal mucosa, reduced regional brain temperature uniformly in half the time needed to reduce body temperature. Here, we evaluated whether initiation of hypothermia with high transnasal airflow provides neuroprotection without adverse effects in the setting of asphyxic CA.

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  • Clinical clearance of a child's cervical spine after trauma is difficult due to unreliable neurologic exams; LSMRI may help by providing a quicker, anesthesia-free alternative to standard MRI for detecting ligamentous injuries.
  • A study conducted over five years across 10 centers evaluated 2,663 children and found that LSMRI had a sensitivity and negative predictive value of over 99% for detecting cervical spine injuries and 100% for unstable injuries.
  • The findings support the use of limited-sequence MRI to effectively rule out significant injuries, suggesting that trauma centers implement LSMRI protocols to reduce the need for anesthesia and MRI times.
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Acute cerebral ischemia triggers a profound inflammatory response. While macrophages polarized to an M2-like phenotype clear debris and facilitate tissue repair, aberrant or prolonged macrophage activation is counterproductive to recovery. The inhibitory immune checkpoint Programmed Cell Death Protein 1 (PD-1) is upregulated on macrophage precursors (monocytes) in the blood after acute cerebrovascular injury.

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The effects of hypothermia on neonatal encephalopathy may vary topographically and cytopathologically in the neocortex with manifestations potentially influenced by seizures that alter the severity, distribution, and type of neuropathology. We developed a neonatal piglet survival model of hypoxic-ischemic (HI) encephalopathy and hypothermia (HT) with continuous electroencephalography (cEEG) for seizures. Neonatal male piglets received HI-normothermia (NT), HI-HT, sham-NT, or sham-HT treatments.

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Article Synopsis
  • - The Stroke Preclinical Assessment Network (SPAN) was created to address concerns about the reliability of preclinical testing for new stroke treatments, following recent failures in clinical trials.
  • - SPAN conducted a rigorous multi-laboratory trial using various animal models to assess candidate treatments in a controlled manner, ensuring aspects like treatment masking and randomization were properly implemented.
  • - By following a standardized protocol across six labs and successfully enrolling a large number of animals, SPAN aims to enhance reproducibility in preclinical research, potentially applying its framework to other medical research areas.
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Intracerebral hemorrhage (ICH) remains the most lethal type of stroke, and effective clinical therapies that can speed up hematoma resolution after ICH are still lacking. While the beneficial effects of IL-10 on ICH recovery have been demonstrated, the clinical translation of IL-10 requires effective delivery methods by which sufficient IL-10 can be delivered to ICH-affected regions in the brain. Here we report the use of a phosphatidylserine (PS) liposome (PSL)-based nanoparticle system for microglia/macrophage-targeted delivery of IL-10 in ICH.

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Article Synopsis
  • Neurologic outcomes after out-of-hospital pediatric cardiac arrests are generally poor, and current methods like therapeutic hypothermia may not be effective due to delays in cooling.
  • Researchers developed a new technique called transnasal cooling, where ambient air is used to cool the nasal passages, resulting in a decrease in brain temperature by 3°C within 25 minutes in piglets of different sizes.
  • This method shows promise for quick brain cooling in emergency situations, as it’s simple, portable, and cost-effective, making it suitable for use before transitioning to traditional cooling methods post-arrest.
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Polynitroxylated PEGylated hemoglobin (PNPH, aka SanFlow) possesses superoxide dismutase/catalase mimetic activities that may directly protect the brain from oxidative stress. Stabilization of PNPH with bound carbon monoxide prevents methemoglobin formation during storage and permits it to serve as an anti-inflammatory carbon monoxide donor. We determined whether small volume transfusion of hyperoncotic PNPH is neuroprotective in a porcine model of traumatic brain injury (TBI) with and without accompanying hemorrhagic shock (HS).

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In most preclinical models of focal ischemic stroke, vascular occlusion is performed under general anesthesia. However, anesthetic agents exert confounding effects on mean arterial blood pressure (MABP), cerebrovascular tone, oxygen demand, and neurotransmitter receptor transduction. Moreover, the majority of studies do not use a blood clot, which more fully models embolic stroke.

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Prolonged lung pathology has been associated with COVID-19, yet the cellular and molecular mechanisms behind this chronic inflammatory disease are poorly understood. In this study, we combine advanced imaging and spatial transcriptomics to shed light on the local immune response in severe COVID-19. We show that activated adventitial niches are crucial microenvironments contributing to the orchestration of prolonged lung immunopathology.

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Background: Characterization of clinical phenotypes in context with tumor and host genomic information can aid in the development of more effective and less toxic risk-adapted and targeted treatment strategies. To analyze the impact of therapy-related hyperbilirubinemia on treatment outcome and to identify contributing genetic risk factors of this well-recognized adverse effect we evaluated serum bilirubin levels in 1547 pediatric patients with acute lymphoblastic leukemia (ALL) and conducted a genome-wide association study (GWAS).

Patients And Methods: Patients were treated in multicenter trial AIEOP-BFM ALL 2000 for pediatric ALL.

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Therapies are limited for pediatric traumatic brain injury (TBI), especially for the very young who can experience long-term consequences to learning, memory, and social behavior. Animal models of pediatric TBI have yielded mechanistic insights, but demonstration of clinically relevant long-term behavioral and/or cognitive deficits has been challenging. We characterized short- and long-term outcomes in a controlled cortical impact (CCI) model of pediatric TBI using a panel of tests between 2 weeks and ∼4 months after injury.

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Purpose: Stigmatized attitudes towards people with mental illness from healthcare providers continues to be a problem affecting recovery in people with mental illness. The process of recovery was explored through digital stories created by service users, with support from nursing students. Stigmatized attitudes in nursing students and stigma resistance in service users were also investigated.

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After traumatic brain injury (TBI), early assessment of secondary injury severity is critically important for estimating prognosis and treatment stratification. Currently, secondary injury severity is difficult to estimate. The objective of this study was to investigate the capacity of non-invasive amide proton transfer-weighted (APTw) magnetic resonance imaging (MRI) techniques to assess TBI injury in different brain regions and predict long-term neurobehavior outcomes.

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Recently, we defined "CML-like" subtype of BCR::ABL1-positive acute lymphoblastic leukemia (ALL), resembling lymphoid blast crisis of chronic myeloid leukemia (CML). Here we retrospectively analyzed prognostic relevance of minimal residual disease (MRD) and other features in 147 children with BCR::ABL1-positive ALL (diagnosed I/2000-IV/2021, treated according to EsPhALL (n = 133) or other (n = 14) protocols), using DNA-based monitoring of BCR::ABL1 genomic breakpoint and clonal immunoglobulin/T-cell receptor gene rearrangements. Although overall prognosis of CML-like (n = 48) and typical ALL (n = 99) was similar (5-year-EFS 60% and 49%, respectively; 5-year-OS 75% and 73%, respectively), typical ALL presented more relapses while CML-like patients more often died in the first remission.

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Throughout the COVID-19 pandemic, hundreds of millions of people worldwide have become new users of respiratory protective devices. Facemasks and KN95 respirators utilizing an ear loop straps system (ELSS) have recently become popular among occupational and non-occupational populations. Part of this popularity is due to the ease of wearability as compared with traditional devices utilizing two headbands, one worn over the head and the other behind the neck-a universal strap system used in NIOSH-certified N95 filtering facepiece respirators (FFRs).

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The goal of this study was to determine whether deficiency of anti-inflammatory cytokine interleukin-10 (IL-10) affects traumatic brain injury (TBI) outcomes in a sex-dependent manner. Moderate TBI was induced by controlled cortical impact in 8-10 week-old wild-type and IL-10-deficient mice. In wild-type mice, serum IL-10 was significantly increased after TBI in males but not in females.

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Background: Cardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery.

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Introduction: Striatal neurons of term newborns are highly vulnerable to hypoxia-ischemia (H-I). In a piglet model of H-I, a dopamine D1 receptor antagonist and an adenosine A2A receptor antagonist alone preferentially protect striatonigral and striatopallidal neurons, respectively. Here, we tested the hypothesis whether the combined treatment with SCH23390, a D1 receptor antagonist, and SCH58261, an A2A receptor antagonist, is more efficacious than individual D1 and A2A receptor antagonist treatment.

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Cerebral ischemia and reperfusion initiate cellular events in brain that lead to neurological disability. Investigating these cellular events provides ample targets for developing new treatments. Despite considerable work, no such therapy has translated into successful stroke treatment.

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Objective: Perinatal ischemic stroke is estimated to occur in 1/2300-1/5000 live births, but early differential diagnosis from global hypoxia-ischemia is often difficult. In this study, we tested the ability of a hand-held transcranial photoacoustic (PA) imaging probe to non-invasively detect a focal photothrombotic stroke (PTS) within 2 h of stroke onset in a gyrencephalic piglet brain.

Approach: About 17 stroke lesions of approximately 1 cmarea were introduced randomly in anterior or posterior cortex via the light/dye PTS technique in anesthetized neonatal piglets (= 11).

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