Long-term safety and functional outcomes of delandistrogene moxeparvovec gene therapy in patients with Duchenne muscular dystrophy: A phase 1/2a nonrandomized trial.

INTRODUCTION/AIMS: Delandistrogene moxeparvovec is indicated in the United States for the treatment of ambulatory pediatric patients aged 4 through 5 years with Duchenne muscular dystrophy (DMD) with a confirmed mutation in the DMD gene. Long-term delandistrogene moxeparvovec microdystrophin protein (a shortened dystrophin that retains key functional domains of the wild-type protein) expression may positively alter disease progression in patients with DMD. We evaluated long-term safety and functional outcomes of delandistrogene moxeparvovec in patients with DMD. METHODS: An open-label, phase 1/2a, nonrandomized controlled trial (Study 101; NCT03375164) enrolled ambulatory males, ≥4 to <8 years old, with DMD. Patients received a single intravenous infusion (2.0 × 1014 vg/kg by supercoiled quantitative polymerase chain reaction) of delandistrogene moxeparvovec and prednisone (1 mg/kg/day) 1 day before to 30 days after treatment. The primary endpoint was safety. Functional outcomes were change from baseline in North Star Ambulatory Assessment (NSAA) and timed function tests. RESULTS: Four patients (mean age, 5.1 years) were enrolled. There were 18 treatment-related adverse events; all occurred within 70 days posttreatment and resolved. Mean NSAA total score increased from 20.5 to 27.5, baseline to year 4, with a mean (standard deviation) change of +7.0 (2.9). Post hoc analysis demonstrated a statistically significant and clinically meaningful 9-point difference in NSAA score, relative to a propensity-score-weighted external control cohort (least-squares mean [standard error] = 9.4 [3.4]; P = .0125). DISCUSSION: Gene transfer therapy with delandistrogene moxeparvovec treatment is well tolerated, with a favorable safety profile. Functional improvements are sustained through 4 years, suggesting delandistrogene moxeparvovec may positively alter disease progression.

Biosynthesis of a new skyllamycin in Streptomyces nodosus: a cytochrome P450 forms an epoxide in the cinnamoyl chain.

Activation of a silent gene cluster in Streptomyces nodosus leads to synthesis of a cinnamoyl-containing non-ribosomal peptide (CCNP) that is related to skyllamycins. This novel CCNP was isolated and its structure was interrogated using mass spectrometry and nuclear magnetic resonance spectroscopy. The isolated compound is an oxidised skyllamycin A in which an additional oxygen atom is incorporated in the cinnamoyl side-chain in the form of an epoxide. The gene for the epoxide-forming cytochrome P450 was identified by targeted disruption. The enzyme was overproduced in Escherichia coli and a 1.43 Å high-resolution crystal structure was determined. This is the first crystal structure for a P450 that forms an epoxide in a substituted cinnamoyl chain of a lipopeptide. These results confirm the proposed functions of P450s encoded by biosynthetic gene clusters for other epoxidized CCNPs and will assist investigation of how epoxide stereochemistry is determined in these natural products.

Percutaneous cecostomy: 25-year two institution experience.

BACKGROUND: Reports of technical success, adverse events, and long-term outcome of percutaneous cecostomy in children are limited. OBJECTIVE: To characterize technical success, 30-day severe adverse events, and long-term outcome of percutaneous cecostomy at two centers. MATERIALS AND METHODS: A retrospective review of hospital course and long-term follow-up (through May 2022) of percutaneous cecostomy tubes placed May 1997 to August 2011 at two children's hospitals was used. Outcomes assessed included technical success (defined as successful tube placement into the colon allowing antegrade colonic enemas), length of stay, 30-day severe adverse events, surgery consults, surgical repair, VP shunt infection, ongoing flushes, tube removal, duration between maintenance tube exchanges, and deaths. RESULTS: A total of 215 procedures were performed in 208 patients (90 institution A, 125 institution B). Tubes were placed for neurogenic bowel (72.1%, n = 155) and functional constipation (27.9%, n = 60). Technical success was 98.1% (211/215) and did not differ between centers (p = 0.74). Surgical repair was required for bowel leakage in 5.1% (11/215) and VP shunt infection was managed in 2.1% (2/95). Compared to functional constipation, patients with neurogenic bowel had higher % tube remaining (65.3% [96/147] versus 25.9% [15/58], p < 0.001) and higher ongoing flushes at follow-up (42.2% [62/147] versus 12.1% [7/58], p < 0.001). Tube removal for dissatisfaction occurred in 15.6% [32/205] and did not differ between groups (p = 0.98). Eight deaths due to co-morbidity occurred after a median of 7.4 years (IQR 9.3) of tube access. CONCLUSION: Percutaneous cecostomy is technically successful in the vast majority of patients and provided durable access in most. Bowel leakage and VP shunt infection are uncommon, severe adverse events.

Characterisation of Modular Polyketide Synthases Designed to Make Pentaene Analogues of Amphotericin B.

Glycosylated polyene macrolides are important antifungal agents that are produced by many actinomycete species. Development of new polyenes may deliver improved antibiotics. Here, Streptomyces nodosus was genetically re-programmed to synthesise pentaene analogues of the heptaene amphotericin B. These pentaenes are of interest as surrogate substrates for enzymes catalysing unusual, late-stage biosynthetic modifications. The previous deletion of amphotericin polyketide synthase modules 5 and 6 generated S. nodosus M57, which produces an inactive pentaene. Here, the chain-terminating thioesterase was fused to module 16 to generate strain M57-16TE, in which cycles 5, 6, 17 and 18 are eliminated from the biosynthetic pathway. Another variant of M57 was obtained by replacing modules 15, 16 and 17 with a single 15-17 hybrid module. This gave strain M57-1517, in which cycles 5, 6, 15 and 16 are deleted. M57-16TE and M57-1517 gave reduced pentaene yields. Only M57-1517 delivered its predicted full-length pentaene macrolactone in low amounts. For both mutants, the major pentaenes were intermediates released from modules 10, 11 and 12. Longer pentaene chains were unstable. The novel pentaenes were not glycosylated and were not active against Candida albicans. However, random mutagenesis and screening may yet deliver new antifungal producers from the M57-16TE and M57-1517 strains.

Generation of Terawatt Attosecond Pulses from Relativistic Transition Radiation.

When a femtosecond duration and hundreds of kiloampere peak current electron beam traverses the vacuum and high-density plasma interface, a new process, that we call relativistic transition radiation (RTR), generates an intense ∼100 as pulse containing ∼1 terawatt power of coherent vacuum ultraviolet (VUV) radiation accompanied by several smaller femtosecond duration satellite pulses. This pulse inherits the radial polarization of the incident beam field and has a ring intensity distribution. This RTR is emitted when the beam density is comparable to the plasma density and the spot size much larger than the plasma skin depth. Physically, it arises from the return current or backward relativistic motion of electrons starting just inside the plasma that Doppler up shifts the emitted photons. The number of RTR pulses is determined by the number of groups of plasma electrons that originate at different depths within the first plasma wake period and emit coherently before phase mixing.

Extremely Dense Gamma-Ray Pulses in Electron Beam-Multifoil Collisions.

Sources of high-energy photons have important applications in almost all areas of research. However, the photon flux and intensity of existing sources is strongly limited for photon energies above a few hundred keV. Here we show that a high-current ultrarelativistic electron beam interacting with multiple submicrometer-thick conducting foils can undergo strong self-focusing accompanied by efficient emission of gamma-ray synchrotron photons. Physically, self-focusing and high-energy photon emission originate from the beam interaction with the near-field transition radiation accompanying the beam-foil collision. This near field radiation is of amplitude comparable with the beam self-field, and can be strong enough that a single emitted photon can carry away a significant fraction of the emitting electron energy. After beam collision with multiple foils, femtosecond collimated electron and photon beams with number density exceeding that of a solid are obtained. The relative simplicity, unique properties, and high efficiency of this gamma-ray source open up new opportunities for both applied and fundamental research including laserless investigations of strong-field QED processes with a single electron beam.

Suppression of Deflecting Forces in Planar-Symmetric Dielectric Wakefield Accelerating Structures with Elliptical Bunches.

Wakefield based accelerators capable of accelerating gradients 2 orders of magnitude higher than present accelerators offer a path to compact high energy physics instruments and light sources. However, for high gradient accelerators, beam instabilities driven by commensurately high transverse wakefields limit beam quality. Previously, it has been theoretically shown that transverse wakefields can be reduced by elliptically shaping the transverse sizes of beams in dielectric structures with planar symmetry. Here, we report experimental measurements that demonstrate reduced transverse wakefields for elliptical beams in planar symmetric structures which are consistent with theoretical models. These results may enable the design of gigavolt-per-meter gradient wakefield based accelerators that produce and stably accelerate high quality beams.

Pediatric Percutaneous Nephrostomy: A Multicenter Experience.

PURPOSE: To analyze technique, outcomes, and complications of a large series of pediatric percutaneous nephrostomy (PCN) procedures performed at 4 tertiary pediatric centers. MATERIALS AND METHODS: Retrospective multicenter study of PCNs performed during an 11-year period. Six hundred seventy-five PCNs were performed on 441 patients (median age: 4 y, range: 1 d-18 y, median weight: 17 kg, range: 0.7-112 kg); 31% were younger than 1 year. The most frequent indications for PCN procedures included hydronephrosis (57%), calculus (14%), and infection (12%). Forty-five percent of patients had severe and 32% had moderate hydronephrosis. RESULTS: Technical success was 99% (n = 668); 7 failures occurred from lost access, during tract dilatation (n = 5) and during staghorn calculi without dilatation (n = 2). General anesthesia was used in 73% of procedures. Combined ultrasound and fluoroscopy was used in 98% of procedures. Of the 668 procedures, 561 (84%) were primary nephrostomy insertions, and 107 (16%) were a variety of exchanges (secondary catheter insertions). Twenty-four of 675 (4%) were transplanted kidneys. Access sites included lower (47%), mid (28%), and upper (12%) poles and pelvis (11%). Catheters were predominantly 7-8 French (n = 352). The mean catheter dwell time was 25 days (0-220 d). Total primary catheter days were 14,482, with an additional 2,241 days after secondary procedures. Follow-up in 653/668 (98%) procedures documented elective removal (79%) and salvage procedures (21%), which included wire exchange (8.7%), nephroureteral stent/catheter conversion (8.8%), and tube upsizing (3.5%). Periprocedural complications occurred in 30/668 (4.5%) procedures: 1 major (0.1%) self-limiting hematuria requiring transfusion and 29 (4.4%) minor complications. CONCLUSIONS: PCN is safe and successful in children of all ages, with few major complications. PCN in children is associated with specific technical challenges and requires ongoing management tailored to the very young to achieve good outcomes.

Follistatin Gene Therapy for Sporadic Inclusion Body Myositis Improves Functional Outcomes.

Sporadic inclusion body myositis, a variant of inflammatory myopathy, has features distinct from polymyositis/dermatomyositis. The disease affects men more than women, most commonly after age 50. Clinical features include weakness of the quadriceps, finger flexors, ankle dorsiflexors, and dysphagia. The distribution of weakness is similar to Becker muscular dystrophy, where we previously reported improvement following intramuscular injection of an isoform of follistatin (FS344) by AAV1. For this clinical trial, rAAV1.CMV.huFS344, 6 × 1011 vg/kg, was delivered to the quadriceps muscles of both legs of six sporadic inclusion body myositis subjects. The primary outcome for this trial was distance traveled for the 6-min walk test. The protocol included an exercise regimen for each participant. Performance, annualized to a median 1-year change, improved +56.0 m/year for treated subjects compared to a decline of -25.8 m/year (p = 0.01) in untreated subjects (n = 8), matched for age, gender, and baseline measures. Four of the six treated subjects showed increases ranging from 58-153 m, whereas two were minimally improved (5-23 m). Treatment effects included decreased fibrosis and improved regeneration. These findings show promise for follistatin gene therapy for mild to moderately affected, ambulatory sporadic inclusion body myositis patients. More advanced disease with discernible muscle loss poses challenges.

Image-guided percutaneous removal of ballistic foreign bodies secondary to air gun injuries.

BACKGROUND: Ballistic injuries with retained foreign bodies from air guns is a relatively common problem, particularly in children and adolescents. If not removed in a timely fashion, the foreign bodies can result in complications, including pain and infection. Diagnostic methods to identify the presence of the foreign body run the entire gamut of radiology, particularly radiography, ultrasound (US) and computed tomography (CT). Removal of the foreign bodies can be performed by primary care, emergency, surgical, and radiologic clinicians, with or without imaging guidance. OBJECTIVE: To evaluate the modalities of radiologic detection and the experience of image-guided ballistic foreign body removal related to air gun injuries within the interventional radiology department of a large pediatric hospital. MATERIALS AND METHODS: A database of more than 1,000 foreign bodies that were removed with imaging guidance by the interventional radiologists at our institution was searched for ballistic foreign bodies from air guns. The location, dimensions, diagnostic modality, duration, complications and imaging modality used for removal were recorded. In addition, the use of sedation and anesthesia required for the procedures was also recorded. RESULTS: Sixty-one patients with ballistic foreign bodies were identified. All foreign bodies were metallic BBs or pellets. The age of the patients ranged from 5 to 20 years. The initial diagnostic modality to detect the foreign bodies was primarily radiography. The primary modality to assist in removal was US, closely followed by fluoroscopy. For the procedure, 32.7% of the patients required some level of sedation. Only two patients had an active infection at the time of the removal. The foreign bodies were primarily in the soft tissues; however, successful removal was also performed from intraosseous, intraglandular and intratendinous locations. All cases resulted in successful removal without complications. CONCLUSION: Image-guided removal of ballistic foreign bodies secondary to air guns is a very effective procedure that can obviate the need for open surgical procedures in children.

Ion Motion Induced Emittance Growth of Matched Electron Beams in Plasma Wakefields.

Plasma-based acceleration is being considered as the basis for building a future linear collider. Nonlinear plasma wakefields have ideal properties for accelerating and focusing electron beams. Preservation of the emittance of nano-Coulomb beams with nanometer scale matched spot sizes in these wakefields remains a critical issue due to ion motion caused by their large space charge forces. We use fully resolved quasistatic particle-in-cell simulations of electron beams in hydrogen and lithium plasmas, including when the accelerated beam has different emittances in the two transverse planes. The projected emittance initially grows and rapidly saturates with a maximum emittance growth of less than 80% in hydrogen and 20% in lithium. The use of overfocused beams is found to dramatically reduce the emittance growth. The underlying physics that leads to the lower than expected emittance growth is elucidated.

Sclerotherapy for splenic cysts in children.

BACKGROUND: Sclerotherapy has been described as a treatment option for nonparasitic pediatric splenic cysts; however, there are limited data on its long-term effectiveness. METHODS: We performed a retrospective review and prospective follow-up imaging study of children treated for nonparasitic splenic cysts at our institution during 2006-2015. Included patients had International Classification of Disease, Ninth Revision, Clinical Modification diagnosis code 289.59 or 759.0 and underwent either sclerotherapy or a partial splenic operation (partial splenectomy, cyst excision, or marsupialization). Charts were reviewed for demographics, imaging, treatments, and complications. Identified patients were contacted and asked to return for splenic ultrasonography. RESULTS: Six surgical patients and 19 sclerotherapy patients were identified. Sclerotherapy patients underwent a median of four treatments with a decrease in the size of the cyst or complete ablation in 89.5% (17/19). Of the two patients who underwent unsuccessful sclerotherapy, one patient had sclerotherapy with sotradecol and ethanol for eight treatments, developed infection, and underwent total splenectomy. The other patient did not improve with sclerotherapy and underwent partial splenectomy. Nine patients (eight patients treated with sclerotherapy and one patient treated with partial splenectomy) were successfully contacted and underwent follow-up imaging at a median follow-up of 2.4 y since last treatment. Of the eight patients treated with sclerotherapy, four patients remained cyst-free, three had small residual asymptomatic cysts stable in size, and one developed a recurrent small asymptomatic cyst; the patient treated with surgery had no recurrence. CONCLUSIONS: Sclerotherapy appears to be an effective and durable alternative treatment for children with splenic cysts.

A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy.

Becker muscular dystrophy (BMD) is a variant of dystrophin deficiency resulting from DMD gene mutations. Phenotype is variable with loss of ambulation in late teenage or late mid-life years. There is currently no treatment for this condition. In this BMD proof-of-principle clinical trial, a potent myostatin antagonist, follistatin (FS), was used to inhibit the myostatin pathway. Extensive preclinical studies, using adeno-associated virus (AAV) to deliver follistatin, demonstrated an increase in strength. For this trial, we used the alternatively spliced FS344 to avoid potential binding to off target sites. AAV1.CMV.FS344 was delivered to six BMD patients by direct bilateral intramuscular quadriceps injections. Cohort 1 included three subjects receiving 3 × 10(11) vg/kg/leg. The distance walked on the 6MWT was the primary outcome measure. Patients 01 and 02 improved 58 meters (m) and 125 m, respectively. Patient 03 showed no change. In Cohort 2, Patients 05 and 06 received 6 × 10(11) vg/kg/leg with improved 6MWT by 108 m and 29 m, whereas, Patient 04 showed no improvement. No adverse effects were encountered. Histological changes corroborated benefit showing reduced endomysial fibrosis, reduced central nucleation, more normal fiber size distribution with muscle hypertrophy, especially at high dose. The results are encouraging for treatment of dystrophin-deficient muscle diseases.

A comparison of pediatric gastrostomy tube placement techniques.

PURPOSE: This study aimed to compare different techniques for placement of gastrostomy tubes in a pediatric population. STUDY DESIGN: A retrospective review was performed for patients less than 18 years of age who underwent gastrostomy tube placement at a single academic children's hospital between 2010 and 2012. Techniques for gastrostomy placement included Open Stamm, percutaneous endoscopic gastrostomy (PEG), fluoroscopy guided, laparoscopic, and laparoscopic assisted PEG. Pre-operative characteristics of patients and post-operative outcomes were compared between techniques. RESULTS: Most patients underwent an Open Stamm (43 %) or PEG (39 %). There were significant differences between groups with respect to primary diagnoses, prior surgeries, and ASA classification. Major complications were rare, with less than 3 % requiring reoperation within 30 days; however, minor complications and returns to the emergency department were common. Unintentional tube dislodgements occurred in 22 % of all patients, with Open Stamm technique identified as an independent predictor of unintentional dislodgement (p < 0.0001). CONCLUSIONS: Although conclusions from this retrospective analysis are limited due to heterogeneity between groups, open Stamm gastrostomy placement in children was associated with increased negative outcomes including unintentional tube dislodgements, returns to the emergency department, and need for reoperation within 30 days. Prospective analysis of the various techniques is needed to confirm that minimally invasive techniques for gastrostomy tube placement are associated with a less complicated post-operative course.

Development of a pediatric-specific clinical probability tool for diagnosis of venous thromboembolism: a feasibility study.

BACKGROUND: Pediatric venous thromboembolism (VTE) is an increasingly common, difficult to diagnose problem. Clinical probability tools (CPT) for adults estimate VTE likelihood, but are not available for children. We hypothesized that a pediatric-specific CPT is feasible. METHODS: Radiology reports were utilized to identify children imaged for suspected VTE. Relevant signs, symptoms, and comorbidity variables, identified from published literature, were extracted from corresponding medical records. Variables associated with pediatric VTE were incorporated into a multivariate logistic regression to create a pilot CPT which was confirmed on a separate cohort. RESULTS: A total of 389 subjects meeting inclusion criteria were identified: 91 with VTE and 298 without. Univariate analysis revealed male gender (odds ratio (OR) = 2.96; P < 0.001), asymmetric extremity (OR = 1.76; P = 0.033), central venous catheter utilization and/or dysfunction (OR = 2.51; P < 0.001), and cancer (OR = 2.35; P = 0.014) as VTE predictive variables. Documentation of an alternate diagnosis was inversely related to VTE (OR = 0.42; P = 0.004). Receiver operating characteristic analysis of the derived CPT demonstrated reasonable ability to discriminate VTE probability in the training cohort (area under the curve (AUC) = 0.73; P < 0.001) and moderate discrimination in a separate validation cohort of 149 children (AUC = 0.64; P = 0.011). CONCLUSION: A pediatric-specific VTE CPT is feasible, would facilitate early diagnosis, and could lead to improved outcomes.

Percutaneous transcervical thoracic duct embolization for treatment of a cervical lymphocele following anterior spinal fusion: a case report.

Thoracic duct injury is an uncommon complication of neck dissection and cervical spinal surgery that is associated with significant morbidity. The authors describe an unusual case of thoracic duct injury during anterior spinal fusion resulting in a large prevertebral lymphocele presenting with dysphagia, respiratory distress, and chyloptysis. Surgical closure of the lymphocele was unsuccessful, and percutaneous drainage and sclerotherapy was performed. A large thoracic duct branch communicating with the lymphocele became evident during sclerotherapy, and embolization of the duct was performed via a percutaneous transcervical approach. Symptoms immediately resolved, and the patient remained asymptomatic at 6-month follow-up.