Elimination of 15N-thymidine after oral administration in human infants.

BACKGROUND: We have developed a new clinical research approach for the quantification of cellular proliferation in human infants to address unanswered questions about tissue renewal and regeneration. The approach consists of oral 15N-thymidine administration to label cells in S-phase, followed by Multi-isotope Imaging Mass Spectrometry for detection of the incorporated label in cell nuclei. To establish the approach, we performed an observational study to examine uptake and elimination of 15N-thymidine. We compared at-home label administration with in-hospital administration in infants with tetralogy of Fallot, a form of congenital heart disease, and infants with heart failure. METHODS: We examined urine samples from 18 infants who received 15N-thymidine (50 mg/kg body weight) by mouth for five consecutive days. We used Isotope Ratio Mass Spectrometry to determine enrichment of 15N relative to 14N (%) in urine. RESULTS/FINDINGS: 15N-thymidine dose administration produced periodic rises of 15N enrichment in urine. Infants with tetralogy of Fallot had a 3.2-fold increase and infants with heart failure had a 4.3-fold increase in mean peak 15N enrichment over baseline. The mean 15N enrichment was not statistically different between the two patient populations (p = 0.103). The time to peak 15N enrichment in tetralogy of Fallot infants was 6.3 ± 1 hr and in infants with heart failure 7.5 ± 2 hr (mean ± SEM). The duration of significant 15N enrichment after a dose was 18.5 ± 1.7 hr in tetralogy of Fallot and in heart failure 18.2 ± 1.8 hr (mean ± SEM). The time to peak enrichment and duration of enrichment were also not statistically different (p = 0.617 and p = 0.887). CONCLUSIONS: The presented results support two conclusions of significance for future applications: (1) Demonstration that 15N-thymidine label administration at home is equivalent to in-hospital administration. (2) Two different types of heart disease show no differences in 15N-thymidine absorption and elimination. This enables the comparative analysis of cellular proliferation between different types of heart disease.

Multimodality Imaging in Ebstein Anomaly.

Ebstein anomaly is the most common form of tricuspid valve congenital anomalies. The tricuspid valve is abnormal with different degrees of displacement of the septal leaflet and abnormal rotation of the valve towards the right ventricular outflow tract. In severe forms, it results in significant tricuspid regurgitation and requires surgical repair. There is an increased interest in understanding the anatomy of the tricuspid valve in this lesion as the surgical repair has evolved with the invention and wide adoption of the cone operation. Multimodality imaging plays an important role in diagnosis, follow-up, surgical planning and post-operative care. This review provides anatomical tips for the cardiac imagers caring for patients with Ebstein anomaly and will help provide image-based personalized medicine.

Super Stretchable and Compressible Hydrogels Inspired by Hook-and-Loop Fasteners.

Inspired by hook-and-loop fasteners, we designed a hydrogel network containing α-zirconium phosphate (ZrP) two-dimensional nanosheets with a high density of surface hydroxyl groups serving as nanopatches with numerous "hooks," while polymer chains with plentiful amine functional groups serve as "loops." Our multiscale molecular simulations confirm that both the high density of hydroxyl groups on nanosheets and the large number of amine functional groups on polymer chains are essential to achieve reversible interactions at the molecular scale, functioning as nano hook-and-loop fasteners to dissipate energy. As a result, the synthesized hydrogel possesses superior stretchability (>2100% strain), resilience to compression (>90% strain), and durability. Remarkably, the hydrogel can sustain >5000 cycles of compression with torsion in a solution mimicking synovial fluid, thus promising for potential biomedical applications such as artificial articular cartilage. This hook-and-loop model can be adopted and generalized to design a wide range of multifunctional materials with exceptional mechanical properties.

Bridging the Cardiac Needs of a Large, Underserved Immigrant and Resettled Refugee Population.

OBJECTIVE: To describe a monthly outreach pediatric cardiology clinic established to better understand the cardiac needs of immigrant/resettled refugee children. STUDY DESIGN: Data obtained between 2014 and 2017 from a monthly pediatric cardiology clinic at a Federally Qualified Health Center were analyzed using descriptive statistics. RESULTS: A total of 366 patients (222 male, 61%) were evaluated. Indications for referral included murmur (242, 66%), nonexertional symptoms (31, 9%), exertional symptoms (16, 4%), history of cardiac surgery/transcatheter interventions (15, 4%), previous diagnosis of heart conditions without intervention (13, 4%), arrhythmia/bradycardia (13, 4%), and others (36, 10%). Echocardiograms were performed on 136 patients (67 were abnormal, 49%). The most common final diagnoses include innocent murmur in 201 (55%), simple congenital heart disease in 61 (16%), complex congenital heart disease in 3 (1%), and acquired heart disease in 3 (1%). A total of 15 patients (4%) were ultimately determined to require surgical or cardiac catherization as an intervention. Patients have been followed for a median of 0.7 years (range 0-3.3 years). CONCLUSIONS: Rates of abnormal echocardiograms suggest a greater likelihood of congenital or acquired heart disease at time of initial consultation compared with nonimmigrant/refugee populations. The most common indication for referral to the outreach pediatric cardiology clinic was a murmur. Collaborative efforts between physicians and support services are essential in assisting this vulnerable population access pediatric subspecialty care.

Delayed puberty and abnormal anthropometry and its associations with quality of life in young Fontan survivors: A multicenter cross-sectional study.

INTRODUCTION: We sought to evaluate the prevalence of delayed puberty and abnormal anthropometry and its association with quality of life (QoL) in young Fontan survivors. METHODS: This was a cross-sectional study at 11 Pediatric Heart Network centers. Demographic and clinical data, anthropomety, and Tanner stage were collected. Anthropometric measurements and pubertal stage were compared to US norms. QoL was assessed using Pediatric Quality of Life inventory (PedsQL). Mixed effects regression modeling adjusting for clustering by center was used to evaluate factors associated with abnormal anthropometry and delayed puberty and associations with QoL. RESULTS: Of the 299 subjects, 42% were female. The median enrollment age was 13.9 years, and the median age at Fontan was 3 years. Fontan survivors had a higher prevalence of short stature relative to normative data (20% vs 5%, P < .0001) and an increased prevalence of abnormal BMI (16% vs 10%, P < .0001) (low [43%] and high [57%]). Fontan subjects, both males (58%) and females (58%), had a delay of 1.5-2 years in ≥1 Tanner stage parameter compared to normal population. There was no association between delayed puberty and QoL. Abnormal anthropometry was associated with lower overall (62.3 ± 17.3 vs 72.5 ± 16.6; P < .001) and physical appearance scores (72.2 ± 27.4 vs 79.8 ± 21.5; P < .01). Lower exercise capacity was associated with abnormal anthropometry and >2 surgeries before Fontan was associated with delayed puberty. Lower family income (<$25 000) and hypoplastic left heart syndrome were associated with lower QoL. CONCLUSION: Compared to the normal population, Fontan survivors have high prevalence of short stature, abnormal BMI and delayed puberty. Abnormal anthropometry, but not delayed puberty, was associated with lower overall QoL and perceived physical appearance scores. Routine screening for abnormal anthropometry, especially in HLHS and in lower socioeconomic status families, should be considered to allow interventions, which might ameliorate the negative psychosocial impact.

Radiopathologic correlation of a tricuspid valve papillary fibroelastoma detected in an infant.

Papillary fibroelastomas are benign primary cardiac tumors that usually arise from the valve apparatus and are rare in the pediatric population. Involvement of the tricuspid valve is even less common with only a few cases reported in the literature. Cardiac magnetic resonance imaging is a valuable examination that aids in differentiating a tumor from a thrombus. We present the case of an 11-month-old girl referred by her pediatrician to investigate a murmur noted since birth. To our knowledge, this is the first report of a pathologically proven papillary fibroelastoma arising from the tricuspid valve characterized by magnetic resonance imaging in an infant.

Accessory Mitral Valve Leaflet Causing Severe Left Ventricular Outflow Tract Obstruction in a Preterm Neonate with a Partial Atrioventricular Septal Defect.

Atrioventricular septal defects represent a class of congenital cardiac malformations that vary in presentation and management strategy depending upon the severity of the particular lesions present. We present the case of a premature neonate who had a partial atrioventricular septal defect and an accessory mitral (or left atrioventricular) valve leaflet. The latter caused severe left ventricular outflow tract obstruction and severely depressed left ventricular function. We found only one other report of this atrioventricular valve abnormality in association with atrioventricular septal defect. To our knowledge, our patient (at a body weight of 1,800 g) is the smallest to survive corrective surgery of an accessory mitral valve leaflet with severe left ventricular outflow tract obstruction. In addition to our patient's case, we discuss the relevant medical literature.

Percutaneous closure of a prosthetic pulmonary paravalvular leak.

Paravalvular leak following prosthetic valve surgery has the potential to cause serious complications such as hemolysis and congestive heart failure. Successful percutaneous closures of prosthetic mitral and aortic paravalvular leaks have been performed as an alternative to reoperation. This case represents the first known report of successful percutaneous closure of a prosthetic pulmonary paravalvular leak in an adult patient with a history of congenital heart disease using two muscular ventricular septal defect occluder devices.

Femoral vein homograft for neoaortic reconstruction in the Norwood stage 1 operation: a follow-up study.

OBJECTIVE: The aim of this study was to analyze our experience with the cryopreserved femoral vein homograft in comparison with standard biomaterials for neoaortic reconstruction in the Norwood stage 1 operation. METHODS: All patients who underwent the Norwood operation from September 2004 to April 2011 were analyzed retrospectively (n = 107). Patients were grouped into group A (cryopreserved femoral vein homograft; n = 72) or group B (other; n = 35). Intergroup comparisons and dimensional analyses of all available angiograms were performed. Two surgical techniques, "standard homograft cuff" and "homograft tube," were compared. RESULTS: Multivariable Cox regression analysis revealed use of biomaterial other than femoral vein (P = .01; hazard ratio, 3.0; 95% confidence interval [CI], 1.4-6.4), weight less than 2.5 kg at the time of stage 1 (P = .01; hazard ratio, 3.7; 95% CI, 1.7-7.8), and need for extracorporeal membrane oxygenator support after stage 1 (P < .001; hazard ratio, 13.8; 95% CI, 5.9-31.9) as significant independent predictors of overall mortality. Improved late survival at 48 months was seen with the femoral vein homograft compared with other biomaterials when a "homograft tube with end-to-side ascending aortic reimplantation technique" was used (group A [75%] vs group B [44%]; P = .03). With the use of the "homograft cuff technique," survival was similar for femoral vein homografts and other biomaterials (group A [67%] vs group B [61%]; P = .85). Similar neoaortic coarctation rates were seen in both groups (A: 25/59 [42%] vs B: 12/26 [46%]; P = .81). A progressive increase in the diameter of the neoaorta was seen over time in both groups with both technical modifications (tube grafts pre-stage 2 vs pre-stage 3: group A [10.61 mm ± 1.93 vs 13.74 mm ± 3.16] [P < .001] and group B [13.93 mm ± 6.71 vs 17.38 mm ± 5.92] [P = .049]); cuff repair pre-stage 2 to pre-stage 3: group A [13.98 mm ± 2.13 vs 19.09 mm ± 4.18] [P = .002] and group B [16.06 mm ± 3.05 vs 19.73 mm ± 2.93] [P < .001]). The neoaortic Z-scores were generous with the use of homograft cuffs and modest when homograft tubes were used and maintained in range over the follow-up time. CONCLUSIONS: Survivals are improved with the use of femoral vein homograft for neoaortic reconstruction for Norwood stage 1 operation, especially when used as a homograft tube with end-to-side aortic reimplantation. Femoral vein homografts have similar recoarctation rates compared with standard biomaterials. Progressive growth/dilation of the neoaorta in proportion to somatic growth is seen with femoral vein tube grafts.

Gold nanoparticles with externally controlled, reversible shifts of local surface plasmon resonance bands.

We have achieved reversible tunability of local surface plasmon resonance in conjugated polymer functionalized gold nanoparticles. This property was facilitated by the preparation of 3,4-ethylenedioxythiophene (EDOT) containing polynorbornene brushes on gold nanoparticles via surface-initiated ring-opening metathesis polymerization. Reversible tuning of the surface plasmon band was achieved by electrochemically switching the EDOT polymer between its reduced and oxidized states.

Poly(allylamine)-encapsulated water-soluble CdSe nanocrystals.

Water-soluble CdSe nanocrystal/poly(allylamine) clusters with sizes ranging between 50 and 200 nm were prepared using 3-amino-1-propanol as a compatibilizing agent. Photoluminescence (PL) quantum yields (QY) up to 20% were achieved in water without the need to clad these CdSe nanocrystals (NCs) with higher band gap inorganic layers. The polymer-to-nanocrystal ratio plays an important role in the internal structure and stability of these polymer/NC clusters, as determined by static and dynamic light scattering in conjunction with PL studies. These results were modeled by using an effective-mass approximation and perturbation theory on the change in dielectric constant of the immediate NC environment. The time evolution of the average cluster radius of gyration and hydrodynamic radius revealed that a higher polymer-to-NC ratio leads to increased PL stability and QY. This is a result of a denser cluster configuration, which affords improved NC passivation. Increasing the ionic strength results in greater nanocluster compaction and higher PL QYs. Decreasing the pH value below 12 resulted in dramatic reduction in PL brightness, despite cluster densification, due to partial ionization and dissolution of the amine-based NC surface-capping agents.

Nanoparticle agglutination: acceleration of aggregation rates and broadening of the analyte concentration range using mixtures of various-sized nanoparticles.

SiO(2) particles of various sizes were prepared and surface modified with biotin-chain-end-functionalized poly(ethylene glycol). Dispersions of these particles were prepared, and their aggregation was induced upon the addition of avidin. The aggregate size and growth rate were monitored by DLS analysis, and SEM and TEM images of freeze-dried samples of the aggregate solutions were used to confirm the DLS data and to image the aggregate size and dimension. A linear correspondence between apparent diameter and time was observed, and both the 20 and 300 nm particles aggregated at slower rates than for the 40 nm particles. These observations were attributed to differences in the average functionality of the systems and the different initial concentrations of particles and avidin. The observed aggregation rates of binary combinations of the three particle sizes (i.e., 20 + 40 nm or 40 + 300 nm) were faster than those of the single-sized mixtures. These results were attributed to the faster flux of smaller particles toward larger particles in the mixture solutions as well as to the potentially larger number of productive collisions possible between mixtures of small particles and large particles versus only similarly sized particles. Combinations of the three sizes of particles were studied to find an empirical optimum formulation for generating large aggregates on a short time scale and over a wide range of analyte concentrations.

Quantitative determination of the chemical composition of silica-poly(norbornene) nanocomposites.

Nanoparticle hybrid materials consisting of a silica core surrounded by a poly(norbornene) brush have been prepared by ring opening metathesis polymerization (ROMP). A quantitative determination of each stage of composite formation has been accomplished, including a determination of the density of surface-bound functional groups, catalyst molecules, and polymer chains. This analysis has enabled the determination of the reaction efficiency between the catalyst and the surface-bound functional groups as well as the determination of the fraction of metal-mediating species that initiate a polymer chain. Control of the chain density was demonstrated by two methods: the use of controlled reaction times between the catalyst and the surface, and the variation of the surface functional group density. Polymer chain densities resulting from composites prepared with different tether structures will also be reported. The resulting brush densities were found to span a wide range, including those previously reported for polymer layers formed by adsorption, grafting of preformed polymer chains, and surface-initiated polymerization (SIP).

Sterile inflammation associated with transradial catheterization and hydrophilic sheaths.

In 1999, we noted the development of inflammation and/or abscesses at the site of radial access in a group of patients. Over a 3-year period, we noted this inflammation in 33 patients out of 2,038 (1.6%) who had catheterization via the radial approach. The radial abscesses occurred in 30 patients out of 1,063 (2.8%) in whom we could confirm the use of a hydrophilic-coated sheath, but in no patient for whom we can document that an uncoated sheath was used. No infectious agent could be implicated, and the time course for the development of the abscess, typically 2 to 3 weeks, seemed long for a bacterial infection. Later patients had biopsies, and granulomatous reactions were seen in most. Additionally, a few of the biopsies showed an amorphous extravascular substance consistent with the catheter coating. All patients had good long-term outcomes.