Richard Keijzer

Richard Keijzer
University of Manitoba | UMN · Department of Surgery

About

123
Publications
11,097
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2,760
Citations
Citations since 2017
57 Research Items
1430 Citations
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20172018201920202021202220230100200300
20172018201920202021202220230100200300

Publications

Publications (123)
Article
Full-text available
Purpose To assess real-world educational outcomes, neurodevelopmental disorders and mental health disorders in patients with intestinal atresia (IA) and compare these to outcomes to age-matched controls. Methods We performed a retrospective case–control study of children with IA born between 1991 and 2017. We evaluated educational outcomes using a...
Article
Full-text available
PurposeWe aimed to determine if Trisomy 21 (T21) affected gastrointestinal outcomes for children with duodenal atresia (DA).Methods We identified children born with DA between 1991 and 2017. Cases were divided into DA with T21 and DA without T21. Ten healthy controls per case were included. Esophageal, ulcerative, obstructive and stomach complaints...
Article
Full-text available
Purpose Here, we establish a tracheal occlusion (TO) model with rat lung explants in nitrofen-induced pulmonary hypoplasia in the congenital diaphragmatic hernia (CDH). Methods We extracted lungs from rats on an embryonic day 18. We mimicked TO in the lung explants by tying the trachea. We assessed lung weight, morphometry, and abundance of Ki-67,...
Preprint
Full-text available
Purpose We aimed to determine if Trisomy 21 (T21) affected gastrointestinal outcomes for children with duodenal atresia (DA). Methods We identified children born with DA between 1991-2017. Cases were divided into DA with T21 and DA without T21. Ten healthy controls per case were included. Esophageal, ulcerative, obstructive and stomach complaints w...
Preprint
Full-text available
PURPOSE Long-term follow-up of congenital duodenal obstruction patients often falls on care providers with little experience of this condition. We performed a systematic review of the long-term outcomes of duodenal obstruction and provide a summary of sequelae care providers should anticipate. METHODS In 2022, after registering with PROSPERA, Medl...
Article
Congenital diaphragmatic hernia (CDH) is a rare birth defect characterized by incomplete closure of the diaphragm and herniation of fetal abdominal organs into the chest that results in pulmonary hypoplasia, postnatal pulmonary hypertension owing to vascular remodelling and cardiac dysfunction. The high mortality and morbidity rates associated with...
Preprint
Full-text available
Purpose: Here, we establish a tracheal occlusion (TO) model with rat lung explants in nitrofen-induced pulmonary hypoplasia in congenital diaphragmatic hernia (CDH). Methods: We extracted lungs from rats on embryonic day 18. We mimicked TO in the lung explants by tying the trachea. We assessed lung weight, morphometry, and abundance of Ki-67, Activ...
Preprint
Full-text available
Rationale: Congenital diaphragmatic hernia (CDH) is characterized by incomplete closure of the diaphragm and lung hypoplasia. The pathophysiology of lung defects in CDH is poorly understood. Objectives: To establish a translational model of human airway epithelium in CDH for pathogenic investigation and therapeutic testing. Methods: We developed a...
Article
Prenatal and postnatal treatment modalities for congenital diaphragmatic hernia (CDH) continue to improve, however patients still face high rates of morbidity and mortality caused by severe underlying persistent pulmonary hypertension and pulmonary hypoplasia. Though the majority of CDH cases are idiopathic, it is believed that CDH is a polygenic d...
Article
The placenta is a dynamic and complex organ that plays an essential role in the health and development of the fetus. Placental disorders can affect the health of both the mother and the fetus. There is currently an unmet clinical need to develop nanoparticle-based therapies to target and treat placental disorders. However, little is known about the...
Article
The pathogenesis of lung hypoplasia in congenital diaphragmatic hernia (CDH), a common birth defect, is poorly understood. The diaphragmatic defect can be repaired surgically, but the abnormal lung development contributes to a high mortality in these patients. To understand the underlying pathobiology, we compared the proteomic profiles of fetal ra...
Article
Nanoparticles administered into the maternal circulation and across the placenta are a potential clinical therapy to treat congenital diseases. The mechanism by which nanoparticles can safely cross the placenta for targeted drug delivery to the fetus remains poorly understood. We demonstrate that the maternal-fetal transfer of passive immunity thro...
Article
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Background Congenital diaphragmatic hernia (CDH) is a birth defect associated with abnormal lung development. Yes-associated protein (YAP) is a core kinase of the Hippo pathway, which controls organ size during development. The absence of YAP protein during lung development results in hypoplastic lungs comparable to the lung phenotype in CDH (Mahon...
Article
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Purpose: It is unclear if musculoskeletal deformities observed in patients with congenital diaphragmatic hernia (CDH), congenital lung lesion (CLL), and esophageal atresia/tracheoesophageal fistula (EA/TEF) are associated with the anomaly or are a result of the surgery required to treat the anomaly. This study compared the prevalence of musculoskel...
Article
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Purpose: We previously demonstrated that absence of miR-200b results in abnormal lung development in congenital diaphragmatic hernia due to imbalance between epithelial and mesenchymal cells. Tenascin C is a highly conserved extracellular matrix protein involved in epithelial to mesenchymal transition, tissue regeneration and lung development. Cons...
Chapter
The septum transversum forms the temporary infrastructure of the ventrolateral diaphragm leaving dorsolateral gaps bilaterally called the pleuroperitoneal canals
Preprint
Full-text available
The pathogenesis of lung hypoplasia in congenital diaphragmatic hernia (CDH), a common birth defect, is poorly understood. The diaphragmatic defect can be repaired surgically, but the abnormal lung development contributes to a high mortality in these patients. To better understand the underlying pathobiology, we used the nitrofen rat model of CDH a...
Article
Purpose The benefit of elective resection of congenital lung malformations continues to be debated. Proponents of resection endorse a decreased risk of respiratory complications as one indication for surgery. Our study aimed to compare the prevalence of respiratory infections in cases, before and after resection of congenital lung malformations, to...
Article
Purpose The aim of this study was to assess real-world educational outcomes and developmental disorders in patients with a history of Hirschsprung disease compared to an age-matched control group. Methods With ethics approval (H2016:014) a retrospective cohort study of all children diagnosed with Hirschsprung disease at a single centre from 1992 t...
Article
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Systemic hypoxia is a common element in most perinatal emergencies and is a known driver of Bnip3 expression in the neonatal heart. Bnip3 plays a prominent role in the evolution of necrotic cell death, disrupting ER calcium homeostasis and initiating mitochondrial permeability transition (MPT). Emerging evidence suggests a cardioprotective role for...
Article
Background Little attention has been given to the long‐term respiratory outcomes of children with gastroschisis. The purpose of this study was to determine if gastroschisis survivors have more respiratory illnesses in their first 10 years‐of‐life compared to age‐matched controls. Methods We performed a retrospective cohort study of all gastroschis...
Article
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Background Congenital diaphragmatic hernia (CDH) and congenital pulmonary airway malformation (CPAM) are two inborn pathologies of the lung of unknown origin. Alterations of gene expression in airway epithelial cells are involved in the pathobiology of both diseases. We previously found decreased expression of the epithelial cell adhesion protein c...
Article
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Introduction Congenital diaphragmatic hernia (CDH) is a life-threatening disease associated with pulmonary hypoplasia. CDH occurs approximately 1 in every 2000–3000 live births, and the pathophysiology is unknown. MicroRNAs are short, non-coding RNAs that control gene expression through post-transcriptional regulation. Based on our previous work, w...
Article
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Purpose: The VICI-trial reported that in patients with congenital diaphragmatic hernia (CDH), mortality or bronchopulmonary dysplasia (BPD) were equivalent using conventional mechanical ventilation (CMV) and high-frequency oscillatory ventilation. The purpose of this study was to determine if the mode of ventilation at the time of CDH repair affec...
Article
Background The true prevalence of hearing loss among children with congenital diaphragmatic hernia (CDH) is unknown, with some studies reporting rates up to 60%. Purpose The purpose of this study was to determine the prevalence of hearing loss among children with CDH and compare it to age-matched controls. Methods We used population-based dataset...
Article
The health-related quality of life (HRQoL) of survivors of congenital diaphragmatic hernia (CDH) is presently unknown. Literature prior to 2015 suggests that CDH survivors have worse HRQoL compared with the general population. However, due to changes in the diagnosis, management, and follow-up of CDH patients, this may no longer be true. The object...
Article
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Systemic hypoxia resulting from preterm birth, altered lung development, and cyanotic congenital heart disease is known to impede the regulatory and developmental pathways in the neonatal heart. While the molecular mechanisms are still unknown, hypoxia induces aberrant cardiomyocyte proliferation, which may be initially adaptive, but can ultimately...
Article
Full-text available
Congenital diaphragmatic hernia (CDH) is a developmental birth defect consisting of a diaphragmatic defect and abnormal lung development. CDH complicates 2.3–2.8 per 10,000 live births. Despite efforts to standardize clinical practice, management of CDH remains challenging. Frequent re-evaluation of clinical practices in CDH reveals that management...
Article
Background/purpose: Magnamosis is a novel technique which utilizes high power magnets to anastomose the esophageal ends in children with esophageal atresia (EA) with or without a tracheoesophageal fistula (TEF), theoretically avoiding the need for thoracotomy. The objective of this study was to compare anastomotic stricture formation requiring dil...
Article
Introduction The purpose of this study was to determine if congenital diaphragmatic hernia (CDH) survivors had worse long-term respiratory outcomes compared with age-matched controls, as measured by inhaled bronchodilator use, inhaled steroid use, and asthma-related physician visits. Materials and Methods We performed a retrospective case-control s...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
Introduction We aimed to determine if the presence of a hernia sac in neonates with isolated congenital diaphragmatic hernia (CDH) was associated with better clinical outcomes. Methods We performed a retrospective cohort study of infants with isolated CDH from 1991 to 2015. Primary outcome measures were oxygen-dependence and mortality at 28 days....
Article
GD30 DH lung showing higher expression of miR‐200b particularly in alveoli. From Eastwood et al., in this issue. https://doi.org/10.1002/pd.5318.
Article
Objective: Profiling of miR-200b expression and its targets (TGF-β2 and ZEB2) in the surgical rabbit CDH model before and after tracheal occlusion (TO). Methods: Thirty-eight timed-pregnant rabbits had left DH creation on gestational day (GD) 23. On GD28, 17 randomly selected fetuses had TO. We harvested fetuses at GD23, GD28 or GD30. We calcula...
Article
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Myocardin is a transcriptional co-activator required for cardiovascular development, but also promotes cardiomyocyte survival through an unclear molecular mechanism. Mitochondrial permeability transition is implicated in necrosis, while pore closure is required for mitochondrial maturation during cardiac development. We show that loss of myocardin...
Article
Congenital diaphragmatic hernia is rare birth defect, which can be easily corrected after birth. The main problem is that herniation of viscera during fetal development impairs lung development, leading to a 30 % mortality and significant morbidity. In isolated cases the outcome can be accurately predicted prenatally by medical imaging. Cases with...
Preprint
BACKGROUND Patient and public involvement in health research is important to produce relevant and impactful results. OBJECTIVE This paper aimed to prioritize and summarize Hirschsprung disease (HD)–related information needs among caregivers of children with HD and pediatric surgeons through partnership with a parent-initiated social media campaign...
Article
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miR-200b plays a role in epithelial-to-mesenchymal transition (EMT) in cancer. We recently reported abnormal expression of miR-200b in the context of human pulmonary hypoplasia in congenital diaphragmatic hernia (CDH). Smaller lung size, a lower number of airway generations, and a thicker mesenchyme characterize pulmonary hypoplasia in CDH. The aim...
Article
Objective: We aimed to evaluate the use of miR-200b as a prenatal transplacental therapy in the nitrofen rat model of abnormal lung development and congenital diaphragmatic hernia (CDH). Background: Pulmonary hypoplasia (PH) and pulmonary hypertension determine mortality and morbidity in CDH babies. There is no safe medical prenatal treatment av...
Article
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p>Background: Appendectomy is considered the gold-standard treatment for acute appendicitis. Recently the need for surgery has been challenged in both adults and children. In children there is growing clinician, patient and parental interest in non-operative treatment of acute appendicitis with antibiotics as opposed to surgery. To date no multicen...
Article
The outcomes of patients diagnosed with congenital diaphragmatic hernia (CDH) have recently improved. However, mortality and morbidity remain high, and this is primarily caused by the abnormal lung development resulting in pulmonary hypoplasia and persistent pulmonary hypertension. The pathogenesis of CDH is poorly understood, despite the identific...
Article
Introduction: The prevention of surgical site infections has received little attention in pediatric surgery. Negative pressure wound therapy is used to treat complex wounds. We hypothesized that this principle could reduce wound infection rates following laparoscopic surgery. We tested this in a randomized controlled trial. Materials and methods:...
Article
MicroRNAs (miRNAs) are small (∼22 nucleotides), non-coding RNA molecules that regulate gene expression post-transcriptionally by inhibiting target mRNAs. Research into the roles of miRNAs in lung development and disease is at the early stages. In this review, we discuss the role of miRNAs in pediatric respiratory disease, including cystic fibrosis,...
Article
Objectives: To identify antenatal predictors of persistent pulmonary hypertension (PPH) and the need for extracorporeal membrane oxygenation (ECMO) in fetuses with congenital diaphragmatic hernia (CDH). Methods: We performed a systematic literature review on antenatal diagnostic tests in fetuses with isolated CDH. The primary outcomes assessed w...
Article
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BACKGROUND: We currently do not know how the herbicide nitrofen induces lung hypoplasia and congenital diaphragmatic hernia in rats. Our aim was to compare the differentially expressed transcriptome of nitrofen-induced hypoplastic lungs to control lungs in embryonic day 13 rat embryos before the development of embryonic diaphragmatic defects. METHO...
Article
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Congenital diaphragmatic hernia (CDH) is characterized by a developmental defect in the diaphragm, pulmonary hypoplasia and pulmonary hypertension. NPAS3 is a PAS domain transcription factor regulating Drosophila tracheogenesis. NPAS3 null mice develop pulmonary hypoplasia in utero and die after birth due to respiratory failure. We aimed to evaluat...
Article
Childhood cancer is the leading cause of mortality in children between 1 and 14 years of age. Malignancy accounts for 18 % of overall childhood mortality. Therapeutic advances in the field of pediatric oncology have helped to increase survival. Nanotechnology is the modification of materials at a nanoscale and can be used to deliver therapeutic age...
Article
Our objective was to determine the fetal in vivo microRNA signature in hypoplastic lungs of human fetuses with severe isolated congenital diaphragmatic hernia (CDH) and changes in tracheal and amniotic fluid of fetuses undergoing fetoscopic endoluminal tracheal occlusion (FETO) to reverse severe lung hypoplasia due to CDH. We profiled microRNA expr...
Article
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Background Social media can be particularly useful for patients or families affected by rare conditions by allowing individuals to form online communities across the world. Objective Our aim in this study was to conduct a descriptive and quantitative analysis of the use of a social media community for Hirschsprung’s Disease (HD). Methods In July...
Article
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MicroRNAs (miRNAs) are short endogenous non-coding RNA molecules (~22 nucleotides) that can regulate gene expression at the post-transcription level. Research interest in the role of miRNAs in lung biology is emerging. MicroRNAs have been identified in a range of processes such as development, homeostasis and inflammatory diseases in lung tissues,...
Article
Full-text available
Congenital diaphragmatic hernia (CDH) is associated with lung hypoplasia and pulmonary hypertension (PH) leading to a high morbidity and mortality. MicroRNAs, affect gene expression and miR-200b is involved in epithelial-mesenchymal transition in cancer and is downregulated in rat nitrofen lungs. We hypothesised that miR-200b regulates lung branchi...
Article
As minimally invasive surgery progresses, there have been attempts to modify the technique to minimize both the number and visibility of incisions. These newer techniques are known by multiple acronyms, including single incision laparoscopic surgery (SILS). The SILS technique has gained popularity in the United States, particularly owing to its per...
Article
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Abstract The aim of this study was to characterize the evolution of lung function and -structure in elastase-induced emphysema in adult mice and the effect of mesenchymal stromal cell (MSC) administration on these parameters. Adult mice were treated with intratracheal (4.8 units/100 g bodyweight) elastase to induce emphysema. MSCs were administered...
Article
Considerable variability exists in the diagnostic approach to acute appendicitis (in children), affecting both quality and costs of care. Interestingly, an international evaluation of what is commonly practiced today has not been performed. We aimed to document current practice patterns in the diagnosis of appendicitis in children and to determine...
Article
Nanomedicine is a rapidly emerging technology and represents an innovative field for therapy. Nanomaterials have intrinsically defined features for biomedical applications due to the high specific surface area, the amazing diversity, versatility in structure and function and the possibility of surface charge. In particular, the functionalization of...
Article
Watercraft-associated trauma (WAT) in children has received little attention so far, despite the potentially severe and debilitating resulting injuries. The aim of this study was to evaluate all cases of major watercraft-associated trauma admitted to the Children's of Alabama during the past 10 years, identify patterns in mechanism and injury, and...
Article
MicroRNAs (miRNAs) constitute a large group of small (∼22 nucleotides), non-coding RNA sequences that are highly conserved among animals, plants and microorganisms, suggesting that microRNAs represent a highly conserved and important regulatory mechanism. They have been demonstrated to play an important role in gene regulation. Recently, miRNAs hav...
Article
Background: The accrual of human tissues from autopsies for diagnostic and translational research has decreased significantly over the last decades. Objectives: The objective of this study was to evaluate our experience with lung biopsy through a minithoracotomy as an alternative for obtaining postmortem tissue when full autopsy is refused in co...
Article
Full-text available
Congenital diaphragmatic hernia (CDH) is a congenital anomaly associated with an increased mortality and morbidity. In this article, we review the currently known etiological and pathogenic factors in CDH.
Article
Congenital diaphragmatic hernia (CDH) can be repaired on or off extracorporeal membrane oxygenation (ECMO). In many centers, operating off ECMO is advocated to prevent bleeding complications. We aimed to compare surgery-related bleeding complications between repair on or off ECMO. All patients with CDH repair and ECMO treatment between January 1, 1...