Publications by authors named "Michael J Wallendorf"

Preterm infants are at risk for ventilatory control instability that may be due to aberrant peripheral chemoreceptor activity. Although term infants have increasing peripheral chemoreceptor contribution to overall ventilatory drive with increasing postnatal age, how peripheral chemoreceptor contribution changes in preterm infants with increasing postmenstrual age is not known. To evaluate peripheral chemoreceptor activity between 32 and 52 weeks postmenstrual age in preterm infants, using both quantitative and qualitative measures.

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Introduction: This study aims to assess the current epidemiology and microbiology of perforated appendicitis, how antibiotic choice and duration correlate with meaningful clinical outcomes, and whether serial white blood cell (WBC) counts provide clinical value.

Methods: Five-year retrospective cohort study, 2015-2019, among 333 consecutive children, ages 0-18 years, treated at St. Louis Children's Hospital for perforated appendicitis.

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We previously demonstrated that infusion of an intestinal peptide called xenin-25 (Xen) amplifies the effects of glucose-dependent insulinotropic polypeptide (GIP) on insulin secretion rates (ISRs) and plasma glucagon levels in humans. However, these effects of Xen, but not GIP, were blunted in humans with type 2 diabetes. Thus, Xen rather than GIP signaling to islets fails early during development of type 2 diabetes.

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Data are lacking on RSB intensity and outcomes after pediatric heart transplantation. PHTS centers received a survey on RSB practices from 2005 to present. PHTS data were obtained for 2010-2013 and integrated with center-matched survey responses for analysis.

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Introduction: Hydrocephalus is a complex neurological disorder with a pervasive impact on the central nervous system. Previous work has demonstrated derangements in the biochemical profile of cerebrospinal fluid (CSF) in hydrocephalus, particularly in infants and children, in whom neurodevelopment is progressing in parallel with concomitant neurological injury. The objective of this study was to examine the CSF of children with congenital hydrocephalus (CHC) to gain insight into the pathophysiology of hydrocephalus and identify candidate biomarkers of CHC with potential diagnostic and therapeutic value.

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Background: The effect of age at transplant on rejection detected by routine surveillance biopsy (RSB) in pediatric heart transplant (HT) recipients is unknown. We hypothesized there would be low diagnostic yield and decreased prevalence of rejection detected on RSB in infants (age <1 year) when compared with children (age 1 to 9 years) and adolescents (age 10 to 18 years).

Methods: We utilized Pediatric Heart Transplant Study (PHTS) data from 2010 to 2013 to analyze moderate-to-severe (ISHLT Grade 2R/3R) cellular rejection (MSR) detected only on RSB (RSBMSR).

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Background: Intraventricular hemorrhage (IVH) is the most frequent, severe neurological complication of prematurity and is associated with posthemorrhagic hydrocephalus (PHH) in up to half of cases. PHH requires lifelong neurosurgical care and is associated with significant cognitive and psychomotor disability. Cerebrospinal fluid (CSF) biomarkers may provide both diagnostic information for PHH and novel insights into its pathophysiology.

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Unlabelled: Peripheral muscarinic acetylcholine receptors regulate insulin and glucagon release in rodents but their importance for similar roles in humans is unclear. Bethanechol, an acetylcholine analogue that does not cross the blood-brain barrier, was used to examine the role of peripheral muscarinic signaling on glucose homeostasis in humans with normal glucose tolerance (NGT; n = 10), impaired glucose tolerance (IGT; n = 11), and type 2 diabetes mellitus (T2DM; n = 9). Subjects received four liquid meal tolerance tests, each with a different dose of oral bethanechol (0, 50, 100, or 150 mg) given 60 min before a meal containing acetaminophen.

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Xenin-25 (Xen) is a neurotensin-related peptide secreted by a subset of enteroendocrine cells located in the proximal small intestine. Many effects of Xen are mediated by neurotensin receptor-1 on neurons. In healthy humans with normal glucose tolerance (NGT), Xen administration causes diarrhea and inhibits postprandial glucagon-like peptide-1 (GLP-1) release but not insulin secretion.

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Objective: To evaluate the clinical effectiveness of bolus-dose fentanyl and midazolam to treat episodic intracranial hypertension in children with severe traumatic brain injury.

Design: Retrospective cohort.

Setting: PICU in a university-affiliated children's hospital level I trauma center.

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Background: Intravenous inotropic therapy can be used to support children awaiting heart transplantation. Although use of this therapy is discouraged in adults because of poor outcomes, its use in children, particularly outpatient, has had limited evaluation. We aimed to evaluate the safety and efficacy of this practice.

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Glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 are incretins secreted by respective K and L enteroendocrine cells after eating and amplify glucose-stimulated insulin secretion (GSIS). This amplification has been termed the "incretin response." To determine the role(s) of K cells for the incretin response and type 2 diabetes mellitus (T2DM), diphtheria toxin-expressing (DT) mice that specifically lack GIP-producing cells were backcrossed five to eight times onto the diabetogenic NONcNZO10/Ltj background.

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Objectives: To examine the association between numbers of primary care provider (PCP) visits for asthma monitoring (AM) over time and acute asthma visits in the emergency department (ED) and at the PCP for Medicaid-insured children.

Methods: We prospectively enrolled 2-10 years old children during ED asthma visits. We audited hospital and PCP records for each subject for three consecutive years.

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OBJECTIVE. The aim of this study was to develop a brief screening battery to predict the on-road performance of drivers who had experienced a stroke. METHOD.

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Background: Potentially driver-impairing (PDI) medications have been associated with poorer driving performance and increased risk of motor vehicle collision.

Objectives: To describe the frequency of medication use and to determine the association between routine use of PDI medications and performance on driving and cognitive tests.

Methods: A total of 225 drivers with medical impairment (mean age 68 ± 12.

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Study Design: Retrospective review of prospectively accrued cohorts.

Objective: We hypothesized that posterior-only vertebral column resection (PVCR) would result in improved postoperative pulmonary function, avoiding pulmonary insults from combined anterior/posterior approaches.

Summary Of Background Data: Pulmonary function after PVCR for severe spinal deformity has not been previously studied.

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Xenin-25 (Xen) is a neurotensin-related peptide secreted by a subset of glucose-dependent insulinotropic polypeptide (GIP)-producing enteroendocrine cells. In animals, Xen regulates gastrointestinal function and glucose homeostasis, typically by initiating neural relays. However, little is known about Xen action in humans.

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Objectives: The authors sought to develop a low-energy electrotherapy that terminates ventricular tachycardia (VT) when antitachycardia pacing (ATP) fails.

Background: High-energy implantable cardioverter-defibrillator (ICD) shocks are associated with device failure, significant morbidity, and increased mortality. A low-energy alternative to ICD shocks is desirable.

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Glucose-dependent insulinotropic polypeptide (GIP) potentiates glucose-stimulated insulin secretion (GSIS). This response is blunted in type 2 diabetes (T2DM). Xenin-25 is a 25-amino acid neurotensin-related peptide that amplifies GIP-mediated GSIS in hyperglycemic mice.

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Objectives: To develop a cognitive and functional screening battery for the on-road performance of older drivers with dementia.

Design: Prospective observational study.

Setting: On-road driving evaluation clinic at an academic rehabilitation center.

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