Publications by authors named "Alexander Cho"

The aim of this study was to construct the sixth in a series of guidelines on the treatment of urolithiasis by the International Alliance of Urolithiasis (IAU) that by providing a clinical framework for the management of pediatric patients with urolithiasis based on the best available published literature. All recommendations were summarized following a systematic review and assessment of literature in the PubMed database from January 1952 to December 2023. Each generated recommendation was graded using a modified GRADE methodology.

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Intraoperative ultrasound is described widely in multiple pathological scenarios in adult practice and in image-guided interventions in children. We aim to describe the technique and range of potential uses of intraoperative ultrasound in paediatric urological surgery, from outlining the process of case selection, preparation, and logistics to demonstrating the ranging benefits of real-time, high spatial resolution ultrasound during resection. At our centre, we use intraoperative ultrasound to assist in a variety of operations.

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Article Synopsis
  • Cloacal malformation is a rare condition that's difficult to diagnose before birth, often showing signs like ascites and pelvic cysts, leading to complex prenatal care.
  • The study reviewed ten patients from a Cloaca database, noting that ascites often leads to severe bowel adhesions and challenging surgical procedures.
  • Findings suggest that the presence of ascites in newborns with this malformation indicates a need for careful preparation by surgeons and anesthetists due to potential complications during initial surgery.
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Background: Traditionally, testicular biopsy is performed using an open surgical approach. Ultrasound-guided percutaneous biopsy is a less invasive alternative and can be performed in children.

Objective: The aim of this study is to report our technique and to assess the diagnostic accuracy and safety of ultrasound-guided percutaneous biopsy of testicular masses in children.

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Urinary stone disease is a common problem in adults, with an estimated 10% to 20% lifetime risk of developing a stone and an annual incidence of almost 1%. In contrast, in children, even though the incidence appears to be increasing, urinary tract stones are a rare problem, with an estimated incidence of approximately 5 to 36 per 100,000 children. Consequently, typical complications of rare diseases, such as delayed diagnosis, lack of awareness, and specialist knowledge, as well as difficulties accessing specific treatments also affect children with stone disease.

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Background: Conservative surgery (CS) brachytherapy (BT) techniques for local therapy in bladder-prostate rhabdomyosarcoma (BP-RMS) seek to retain organ function. We report bladder function after high-dose rate (HDR) BT combined with targeted CS for any vesical component of BP-RMS.

Procedure: Prospective cohort of all BP-RMS patients between 2014 and 2019 receiving HDR-BT (iridium-192, 27.

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Objective: To evaluate the safety and efficacy of ethylene vinyl alcohol (EVOH) copolymer for the treatment of a variety of peripheral vascular pathologies.

Results: Between October 2010 and October 2017, 43 patients who underwent total 54 EVOH embolization procedures for the treatment of peripheral vascular pathologies were included. The cases which involved the use of EVOH for the treatment of nonvascular, neurologic, ophthalmologic, otolaryngologic or head-neck pathologies were excluded.

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In children, removal of a post-procedural JJ stent requires a further cystoscopy under general anaesthetic. We describe securing the distal end of the ureteric stent to the tip of a balloon catheter at the end of the primary procedure. Once post-operative oedema has subsided, the stent is removed seamlessly in tandem with the balloon catheter.

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Vascular malformations of the urinary bladder are rare in children and their management can be challenging. This minimally invasive approach was first described by the authors in lead 2013 and demonstrated that cystoscopic injections were safe without breech into the peritoneal cavity [1]. Cystoscopic injection sclerotherapy can be very successful in managing the complications of bladder vascular malformations and thereby avoiding extensive surgery.

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Although there has been increased utilization of bleomycin in the treatment of low-flow vascular malformations in children, previous studies report minor adverse effects limited to skin changes/necrosis and flu-like symptoms (Horbach et al. in J Plast Reconstr Aesthet Surg 69(3):295-304, 2016). However, there have been rare reported cases of pulmonary injury observed in children after bleomycin intralesional administration.

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Organ chips can recapitulate organ-level (patho)physiology, yet pharmacokinetic and pharmacodynamic analyses require multi-organ systems linked by vascular perfusion. Here, we describe an 'interrogator' that employs liquid-handling robotics, custom software and an integrated mobile microscope for the automated culture, perfusion, medium addition, fluidic linking, sample collection and in situ microscopy imaging of up to ten organ chips inside a standard tissue-culture incubator. The robotic interrogator maintained the viability and organ-specific functions of eight vascularized, two-channel organ chips (intestine, liver, kidney, heart, lung, skin, blood-brain barrier and brain) for 3 weeks in culture when intermittently fluidically coupled via a common blood substitute through their reservoirs of medium and endothelium-lined vascular channels.

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Background: Current differentiation protocols to produce cardiomyocytes from human induced pluripotent stem cells (iPSCs) are capable of generating highly pure cardiomyocyte populations as determined by expression of cardiac troponin T. However, these cardiomyocytes remain immature, more closely resembling the fetal state, with a lower maximum contractile force, slower upstroke velocity, and immature mitochondrial function compared with adult cardiomyocytes. Immaturity of iPSC-derived cardiomyocytes may be a significant barrier to clinical translation of cardiomyocyte cell therapies for heart disease.

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Background: Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular diseases (CVD) and vascular health. Peripheral blood-derived CD34+ progenitor cells have been used as biomarker for CVD risk and may play a similar role in OSA and CVD risk assessment. Although there are some controversial results in the literature, OSA patients may have a reduction in the number and function of CD34+ cells.

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The high-risk surgical patient only constitutes approximately 4% of the elective non-cardiac surgical population but contributes to the vast majority of in-hospital deaths following surgery. This, in conjunction with a high morbidity rate, can lead to a perioperative pathway fraught with challenges. It is incredibly difficult to anticipate which complications may arise and the risks involved before surgery.

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Purpose: Seizures are common in term infants with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia. Although phenobarbital (PHB) is generally considered first-line therapy, some centers have embraced third-generation antiepileptic drugs (AEDs) such as levetiracetam (LEV) given the impression of comparable efficacy and superior tolerability. We set out to compare the efficacy of PHB and LEV in a large single-center cohort.

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The neurovascular unit (NVU) regulates metabolic homeostasis as well as drug pharmacokinetics and pharmacodynamics in the central nervous system. Metabolic fluxes and conversions over the NVU rely on interactions between brain microvascular endothelium, perivascular pericytes, astrocytes and neurons, making it difficult to identify the contributions of each cell type. Here we model the human NVU using microfluidic organ chips, allowing analysis of the roles of individual cell types in NVU functions.

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A low-cost, semirealistic, multimaterial prototype phantom of the neck was developed for computed tomography- and ultrasound-guided interventions, using three-dimensional (3D) printing with a variety of materials as well as through molding techniques. This dual-modality phantom can be used by trainees for practicing procedures and can also serve as a prototype for developing more complex and realistic 3D-printed models, particularly with the continued development and advancement in multimaterial 3D printing technologies.

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Objective: Psychostimulant medications are the gold standard of treatment for attention-deficit/hyperactivity disorder (ADHD); however, a significant minority (∼30%) of individuals with ADHD fail to respond favorably. Noradrenergic agents are increasingly used as ADHD monotherapies or adjuncts for suboptimal stimulant response, yet knowledge of their cortical effects is limited. This study is the first to examine comparative effects of guanfacine (an α adrenergic 2A agonist), psychostimulant, and their combination on resting state cortical activity in ADHD.

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Inspired by the relatively simple morphological blueprint provided by batoid fish such as stingrays and skates, we created a biohybrid system that enables an artificial animal--a tissue-engineered ray--to swim and phototactically follow a light cue. By patterning dissociated rat cardiomyocytes on an elastomeric body enclosing a microfabricated gold skeleton, we replicated fish morphology at 1/10 scale and captured basic fin deflection patterns of batoid fish. Optogenetics allows for phototactic guidance, steering, and turning maneuvers.

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In vitro disease models offer the ability to study specific systemic features in isolation to better understand underlying mechanisms that lead to dysfunction. Here, we present a cardiac dysfunction model using angiotensin II (ANG II) to elicit pathological responses in a heart-on-a-chip platform that recapitulates native laminar cardiac tissue structure. Our platform, composed of arrays of muscular thin films (MTF), allows for functional comparisons of healthy and diseased tissues by tracking film deflections resulting from contracting tissues.

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Introduction: Recent recommendations have lowered the ideal age of surgery for undescended testis (UDT) to 3-6 months of age. However, many publications demonstrate that age at surgery is still above the recommended age of 1 year as originally suggested in 1996.

Aim: Through a web-based educational survey, we aimed to combine questions regarding General Practioner's (GPs) management of these patients with educational slides with advice to update them with current recommendations.

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Article Synopsis
  • A 31-year-old man felt severe chest pain and went to the doctor.
  • Doctors found a big mass near his bronchus (a tube that helps us breathe) and another around a major blood vessel.
  • He was diagnosed with a rare condition called idiopathic fibrosing mediastinitis, treated with medications, and after nine months, the masses got smaller and improved!
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Moving from the study conducted in 2004 on adult surgeons we want to analyze the ergonomics applied in pediatric minimally invasive surgery. An online survey was conducted among the members of the European Paediatric Surgeons' Association that included 14 questions pertaining to demographic, surgical glove size, double glove use, prior hand surgery, and the ease or difficulty in using different types of laparoscopic instruments. A total of 138 pediatric surgeons completed the survey.

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