Comparative transcatheter occlusion of patent ductus arteriosus: multicenter collaborative study across pediatric and veterinary cardiology centers.

INTRODUCTION/OBJECTIVE: Transcatheter therapeutics have revolutionized treatment of patent ductus arteriosus (PDA). Greater understanding of corrective interventions across species can advance best practices, protocols, and outcomes while minimizing adverse events. The objective of this study was to describe characteristics and outcomes in children and dogs undergoing transcatheter PDA occlusion. ANIMALS, MATERIALS AND METHODS: This was a multicenter, retrospective cohort study from two pediatric and three veterinary centers. Demographics, procedural characteristics, and outcomes were assessed. RESULTS: Data included 202 children and 106 dogs treated from July 2019 to June 2021. Forty-five (23%) children and 19 (18%) dogs had congestive heart failure prior to catheterization. Transvenous and transarterial approaches for deployment were most used in children and dogs, respectively. All children had percutaneous vascular access compared to 17 (16%) dogs. Intraprocedural anticoagulation was standard for children (100% of 165 reported), but not for dogs (2/103). The median (interquartile range) pulmonary ostium diameter in children was 2.2 mm (1.5-3.0 mm) and 3.0 mm (2.0-4.2 mm) in dogs when all body sizes were considered (P<0.001). Amplatzer™ Duct Occluder was most commonly used in children (64/202, 32%); the Amplatz® Canine Duct Occluder was used in dogs (96/100, 96%). Closure was manual compression in all children, whereas vessel ligation was most used in dogs (74/104, 73%). Successful device deployment was achieved in 197 (98%) children and 98 (93%) dogs (P=0.03). Major reasons for failure included device embolization in six (2.9%) children and PDA morphology concerns in four (3.8%) dogs. CONCLUSIONS: Transcatheter PDA occlusion is successful in children and dogs. Study data might be useful for optimizing transcatheter therapeutics and animal models for interventional cardiology.

Experimental investigation of gamma-ray interaction parameters and buildup factors in lanthanide compounds: Insights into penetration depth.

This experimental investigation focuses on the gamma-ray interaction parameters and the buildup factor in lanthanide compounds (CeO2, Ce(SO4)2, Dy2(SO4)3, C3O9Sm2, C3Gd2O9, Pr2O3). These compounds were exposed to weak radioactive gamma sources with energies of 356, 511, 662, 1173, 1275, and 1332 keV by adopting narrow and broad beam geometry experimental arrangements. The incident and transmitted radiation intensities were measured using a NaI (Tl) detector. Experimentally measured values of mass attenuation coefficient and effective atomic number of lanthanide compounds were found to be in precise agreement with theoretical values obtained from NIST XCOM and Direct-Zeff database respectively. Additionally, the experimentally determined buildup factor values were compared with energy absorption buildup factor (EABF) and exposure buildup factor (EBF) values obtained from Phy-X/PSD software, providing insights into the gamma-ray penetration depth in terms of mean free path (MFP). At 356 keV, the EABF analysis showed that most compounds had a penetration depth of around 8 mean free paths. In contrast, the EBF analysis indicated penetration depths exceeding 10 mean free paths for all compounds except Ce (SO4)2. This new approach holds immense potential for transformative advancements in medical diagnostics, therapy, and the development of innovative technologies in nuclear sciences.

An experimental approach to determine the gamma radiation interaction mean free path and exposure buildup factor for biomolecules.

This experimental approach was designed to understand the gamma interaction parameters for the essential biomolecules, including starch soluble, cholesterol, myristic acid, glucose, oxalic acid, dextrose, salicylic acid, ethyl cellulose and sucrose. The empirical determination of gamma interaction parameters, such as interaction mean-free-path (MFP), buildup factor, and effective atomic number (Zeff) was performed by measuring mass attenuation coefficient (µ/ρ) at energies of 356 keV, 511 keV, 662 keV, 1173 keV, 1275 keV and 1332 keV. This was achieved using weak radioactive sources and a NaI(Tl) scintillation spectrometer with collimated and non-collimated transmission geometry. The experimentally determined values of gamma-ray interaction parameters were obtained non-destructively and precisely agreeing with the expected values from simulations and codes. In addition, the research findings also revealed a novel trend in gamma interaction mean free path as a function of energy and variable buildup factors for the selected biomolecules. These research findings provide valuable insight into the process of gamma radiation interaction. This approach may fulfil the increasing demand of medical, technical and academic research laboratories for a cost-effective and reliable empirical methodology to understand gamma radiation interaction with matter.

Investigation of the nuclear radiation interaction parameters of selected polymers for radiation therapy and dosimetry.

The mass attenuation coefficient (MAC), effective atomic number (Zeff), equivalent atomic number (Zeq), fast neutron removal cross-section (FNRCS), energy absorption buildup factor (EABF), mass-energy absorption coefficient (MenAC), relative kerma, and computed tomography (CT) numbers were calculated for the alginates, bisphenol A-glycidyl methacrylate (Bis-GMA), chitin, hyaluronic acid, polycaprolactone (PCL), polyether ether ketone (PEEK), polyethylene glycol (PEG), polyglycolide (PGA), polylactic acid (PLA), poly lacto-co-glycolic acid (PLGA), poly methyl methacrylate (PMMA), poly vinyl alcohol (PVA), polyvinylpyrrolidone (PVP), triethylene glycol dimethacrylate (TEGDMA), and urethane dimethacrylate (UDMA) polymers using the Phy-X/PSD and Py-MLBUF software. The total stopping power (TSP) of electrons, protons, and alpha particles was calculated for the selected polymers using the ESTAR, PSTAR, and ASTAR programs. The effective atomic number for absorption and charged particle (electron, proton, alpha, and carbon ion) interactions were estimated for the selected polymers using Phy-X/ZeXTRa software. The FNRCS values of Bis-GMA, PCL, PEG, PMMA, and PVP were similar to those of the human tissues. For the selected polymers, the Zeff values for electron, proton, alpha, and carbon ion interactions of PCL, PEG, PLGA, and PVA were similar to those of human tissues, except for the cortical bone, across the entire energy range. These results are expected to assist in selecting suitable polymers as tissue-equivalent materials in the desired energy range for photon, neutron, and charged-particle interactions. This study is expected to be useful for radiation therapy and dosimetry.

Investigation of gamma-ray shielding parameters of bismuth phospho-tellurite glasses doped with varying Sm2O3.

The gamma ray shielding parameters such as mass attenuation coefficient, effective atomic number, equivalent atomic number, exposure buildup factor, and energy absorption buildup factor were determined for the 47.5P2O5+45ZnO+(5-x) Bi2O3+2.5TeO2 +xSm2O3 glass system using Phy-X/PSD software in the energy range from 0.015 to 15 MeV at penetration depths of 1-40 MFP. To understand the effect of Sm2O3 on gamma ray shielding parameters in selected glass system, the Sm2O3 was varied in the glass from 0.01 to 1 mol%. The calculated results show that the mass attenuation coefficient decreases with increasing photon energy but not influenced by the addition of Sm2O3. The Zeq values are lower in low (≤100 keV) and high energy regions (1 MeV-15 MeV) and higher in the medium energy region, indicating that the Compton scattering is significant in the medium energy region. The values of exposure buildup factors and energy absorption buildup factors are smaller in the low and high energy regions than in the intermediate energy region, indicating that the photo absorption and pair creation processes are important in the low and high energy regions, respectively. The 1% mole concentration of Sm2O3 in the selected glass shows higher exposure buildup factor and energy absorption buildup factor values in the intermediate energy region. The high density, high effective atomic number, and transparency to visible light of these materials indicate that they can be used as shielding materials in nuclear reactors and nuclear technology.

Impact of balloon atrial septostomy in neonates with transposition of great arteries.

OBJECTIVE: To examine the impact of balloon atrial septostomy (BAS) on cardio-respiratory status, need for prostaglandin E(1) (PGE(1)) and postoperative outcomes in infants with transposition of great arteries (TGA). STUDY DESIGN: Single-center retrospective review of consecutive neonates with dTGA. RESULT: BAS was performed in 42 (70%) infants and resulted in a significant increase in minimum (61 to 76%) and maximum (80 to 90%) oxygen (O(2)) saturations and a drop in FiO(2). BAS was 'successful,' that is, PGE(1) was discontinued in 16 (38%) infants. Three infants died; four infants developed strokes, all of whom had undergone BAS. The duration of hospitalization, ventilation and O(2) need did not differ between infants without BAS, 'successful' BAS and unsuccessful BAS. PGE(1) duration correlated with duration of hospitalization, ventilation, O(2) need and peak respiratory severity score (P<0.03). CONCLUSION: We speculate that limiting BAS for clinical hypoxemia and aggressive weaning of PGE(1) following BAS would improve outcomes.

Associations between retinal nerve fiber layer abnormalities and optic nerve examination.

OBJECTIVE: Retinal nerve fiber layer (RNFL) abnormalities detected by optical coherence tomography (OCT) are useful markers for axonal loss and visual dysfunction in multiple sclerosis (MS), but their role in routine clinical management is not well-studied. METHODS: Clinical and OCT examinations were performed on 240 patients attending a neurology clinic. Using OCT 5th percentile to define abnormal RNFL thickness, we compared eyes classified by neurologists as having optic atrophy to RNFL thickness, and afferent pupillary defect (APD) to RNFL thickness ratios of eye pairs. RESULTS: Mean RNFL thickness was less in eyes classified by neurologists as having optic atrophy (79.4 ± 21 µm; n=63) vs those without (97.0 ± 15 µm; n=417; p < 0.001, t test) and in eyes with an APD (84.1 ± 16 µm; n=44) than without an APD (95.8 ± 17 µm; n=436; p < 0.001). Physicians' diagnostic accuracy for detecting pallor in eyes with an abnormal RNFL thickness was 79% (sensitivity=0.56; specificity=0.82). Accuracy for detecting a RAPD in patients with mean RNFL ratio (affected eye to unaffected eye) <0.90 was 73% (sensitivity=0.30; specificity=0.86). Ability to detect visual pathway injury via assessment of atrophy and APD differed between neurologists. CONCLUSIONS: OCT reveals RNFL abnormality in many patients in whom eyes are not classified by neurologic examiners as having optic atrophy. Further study is needed to define the role of OCT measures in the context of examinations for optic atrophy and APD by neuroophthalmologists. OCT-measured RNFL thickness is likely to have an important future role in the clinical setting.

Clinical risk factors associated with extubation failure in ventilated neonates.

We conducted this study to find out the incidence of extubation failure (EF) in ventilated neonates and associated clinical risk factors. Eighty two ventilated neonates were followed up to 48 hours post extubation to look for EF. Twenty two babies (26.8%) had EF. The common risk factors for EF were presence of patent ductus arteriosus, post-extubation lung collapse and acquired pneumonia. The duration of ventilation, and maximum and pre-extubation alveolar arterial oxygen gradients (AaDO2) were significantly higher (P<0.05) in EF group. The incidence of sepsis (P=0.034), anemia (P=0.004) and pneumonia (P=0.001) were significantly higher in EF group. Detection of significant PDA and adequate post extubation care may help to reduce rate of extubation failure in neonates.

Vitamin D status and effect of low-dose cholecalciferol and high-dose ergocalciferol supplementation in multiple sclerosis.

BACKGROUND: Vitamin D is important for bone health and immune regulation, and has been shown to be low in multiple sclerosis (MS). We sought to determine the effect of over the counter low dose cholecalciferol (LDC) and high dose ergocalciferol (HDE) on the vitamin D levels in MS patients. METHODS: We retrospectively evaluated serum 25-hydroxy-vitamin D [25(OH)D] levels of 199 patients (CIS, n = 32; RRMS, n = 115; PPMS, n = 10; SPMS, n = 16; Transverse Myelitis (TM), n = 9; other neurological diseases, n = 16) attending our clinic between 2004 and 2008. We examined the change in 25(OH)D levels in 40 MS patients who took either LDC (< or =800 IU/day) or HDE (50,000 IU/day for 7-10 days, followed by 50,000 IU weekly or biweekly). RESULTS: The average 25(OH)D level was 71 +/- 39 nmol/L (Mean +/- SD), and 167(84%) patients had insufficient levels (< or =100 nmol/L) of 25(OH)D. The patients supplemented with LDC did not have a significant increase in their 25(OH)D levels. However, 25(OH)D levels increased by 42 nmol/L (P = 0.01) in the patients originally taking LDC and then prescribed HDE. Optimal levels (> or =100 nmol/L) were only achieved in less than 40% of patients. CONCLUSIONS: We conclude that large numbers of patients with MS and TM in our cohort are deficient in vitamin D. HDE significantly elevated 25(OH)D levels in MS patients and was more effective at increasing 25(OH)D levels than LDC. Prospective studies are required to determine appropriate dosing regimen to achieve optimal levels in the majority of MS patients and to ascertain the safety, immunological response, and ultimately the clinical efficacy of vitamin D replacement therapy.