The prognostic value of prognostic nutritional index in postoperative onset of PAH in children with isolated VSD: a prospective cohort study based on propensity score matching analysis.

Background: The mechanism of pulmonary arterial hypertension (PAH) after surgery/intervention for isolated venticlular septal defect (VSD) in children is unknown. Reliable prognostic indicators for predicting postoperative PAH are urgently needed. Prognostic nutration index (PNI) is widely used to predict postoperative complications and survival in adults, but it is unclear whether it can be used as an indicator of prognosis in children. Methods: A total of 251 children underwent VSD repair surgery or interventional closure in Hunan Children's Hospital from 2020 to 2023 were collected. A 1:1 propensity score matching (PSM) analysis was performed using the nearest neighbor method with a caliper size of 0.2 Logistics regression analysis is used to examine factors associated with the development of PAH. Results: The cut-off value for PNI was determined as 58.0. After 1:1 PSM analysis, 49 patients in the low PNI group were matched with high PNI group. Children in the low PNI group had higher risk of postoperative PAH (P = 0.002) than those in the high PNI group. Multivariate logistics regression analysis showed that PNI (RR: 0.903, 95% CI: 0.816-0.999, P = 0.049) and tricuspid regurgitation velocity (RR: 4.743, 95% CI: 1.131-19.897, P = 0.033) were independent prognostic factors for the development of PAH. Conclusion: PNI can be used as a prognostic indicator for PAH development after surgery/intervention in children with isolated VSD.

COVID-19 vaccination for children with pulmonary hypertension: efficacy, safety and reasons for opting against vaccination.

Objective: To determine the reasons why pulmonary hypertension (PH) children refused vaccination against COVID-19, evaluate the safety and efficacy of COVID-19 vaccine in PH children. Study design: This retrospective cohort study included congenital heart disease-associated pulmonary arterial hypertension (CHD-PAH) and bronchopulmonary dysplasia associated PH (BPD-PH) children who were divided into vaccinated group and non-vaccinated group. Univariate logistic regression analysis and multivariate logistic regression analysis were conducted to explore the reasons why PH children refused COVID-19 vaccine. Then, the prevalence, the number of symptoms, and the severity of COVID-19 disease were compared between the vaccinated and unvaccinated groups. Result: We included 73 children and 61 children (83.6%) were unvaccinated. The main reasons for not being vaccinated were fear of worsening of existing diseases (31%). Age < 36 months (RR: 0.012; P < 0.001) and the presence of comorbidities (RR = 0.06; P = 0.023) were risk factors influencing willingness to vaccinate. The most common adverse events (AEs) were injection site pain (29.6%). COVID-19 vaccines are safe for PH children. The prevalence of COVID-19 disease decreased in PH children after vaccination (RR = 0.51; P = 0.009). 1 month after negative nucleic acid test or negative antigen test, PH children in the vaccinated group had fewer symptoms (P = 0.049). Conclusions: The vaccination rate of COVID-19 vaccine is low in CHD-PAH and BPD-PH children while COVID-19 vaccines are safe. Vaccination can reduce the prevalence of COVID-19 disease and the number of symptoms 1 month after negative nucleic acid or antigen tests.

Lactylation: novel epigenetic regulatory and therapeutic opportunities.

Lactate, which is an end product of glycolysis, has traditionally been considered a metabolic waste. However, numerous studies have demonstrated that lactate serves metabolic and nonmetabolic functions in physiological processes and multiple diseases. Cancer and pulmonary arterial hypertension have been shown to undergo metabolic reprogramming, which is accompanied by increased lactate production. Metabolic reprogramming and epigenetic modifications have been extensively linked; furthermore, posttranslational modifications of histones caused by metabolites play a vital role in epigenetic alterations. In this paper, we reviewed recent research on lactate-induced histone modifications and provided a new vision about the metabolic effect of glycolysis. Based on our review, the cross talk between the metabolome and epigenome induced by glycolysis may indicate novel epigenetic regulatory and therapeutic opportunities. There is a magnificent progress in the interaction between metabolomics and epigenomics in recent decades, but many questions still remained to be investigated. Lactylation is found in different pathophysiological states and leads to diverse biological effects; however, only a few mechanisms of lactylation have been illustrated. Further research on lactylation would provide us with a better understanding of the cross talk between metabolomics and epigenomics.

Meta-Analysis of Pulmonary Artery Denervation for Treatment of Pulmonary Hypertension.

INTRODUCTION: Pulmonary artery denervation (PADN) can reduce the sympathetic nervous system (SNS) activity, reduce pulmonary artery pressure (PAP), and improve the quality of life in patients with pulmonary hypertension (PH). We conducted a systematic meta-analysis of the effectiveness of PADN in the treatment of PH patients. METHODS: This is a comprehensive literature search including all public clinical trials investigating the effects of PADN on PH. Outcomes were mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), cardiac output (CO), right ventricular (RV) Tei index, 6-minute walk distance (6MWD), and New York Heart Association (NYHA) cardiac function grading. RESULTS: A total of eight clinical studies with 213 PH patients who underwent PADN were included. Meta-analysis showed that after PADN, mPAP (mean difference [] -12.51, 95% confidence interval [CI] -17.74 to -7.27, P<0.00001) (mmHg) and PVR ( -5.17, 95% CI -7.70 to -2.65, P<0.0001) (Wood unit) decreased significantly, CO ( 0.59, 95% CI 0.32 to 0.86, P<0.0001) (L/min) and 6MWD ( 107.75, 95% CI 65.64 to 149.86, P<0.00001) (meter) increased significantly, and RV Tei index ( -0.05, 95% CI -0.28 to 0.17, P=0.63) did not change significantly. Also after PADN, the proportion of NYHA cardiac function grading (risk ratio 0.23, 95% CI 0.14 to 0.37, P<0.00001) III and IV decreased significantly. CONCLUSION: This meta-analysis supports PADN as a potential new treatment for PH. Further high-quality randomized controlled studies are needed.

Meta-Analysis of Pulmonary Artery Denervation for Treatment of Pulmonary Hypertension

ABSTRACT Introduction: Pulmonary artery denervation (PADN) can reduce the sympathetic nervous system (SNS) activity, reduce pulmonary artery pressure (PAP), and improve the quality of life in patients with pulmonary hypertension (PH). We conducted a systematic meta-analysis of the effectiveness of PADN in the treatment of PH patients. Methods: This is a comprehensive literature search including all public clinical trials investigating the effects of PADN on PH. Outcomes were mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), cardiac output (CO), right ventricular (RV) Tei index, 6-minute walk distance (6MWD), and New York Heart Association (NYHA) cardiac function grading. Results: A total of eight clinical studies with 213 PH patients who underwent PADN were included. Meta-analysis showed that after PADN, mPAP (mean difference [MD] -12.51, 95% confidence interval [CI] -17.74 to -7.27, P<0.00001) (mmHg) and PVR (MD -5.17, 95% CI -7.70 to -2.65, P<0.0001) (Wood unit) decreased significantly, CO (MD 0.59, 95% CI 0.32 to 0.86, P<0.0001) (L/min) and 6MWD (MD 107.75, 95% CI 65.64 to 149.86, P<0.00001) (meter) increased significantly, and RV Tei index (MD -0.05, 95% CI -0.28 to 0.17, P=0.63) did not change significantly. Also after PADN, the proportion of NYHA cardiac function grading (risk ratio 0.23, 95% CI 0.14 to 0.37, P<0.00001) III and IV decreased significantly. Conclusion: This meta-analysis supports PADN as a potential new treatment for PH. Further high-quality randomized controlled studies are needed.

Progress of Pathogenesis in Pediatric Multifocal Atrial Tachycardia.

Multifocal atrial tachycardia (MAT) is defined as irregular P-P, R-R, and P-R intervals, isoelectric baseline between P waves, and ventricular rate over 100 beats/min. Although the prognosis of pediatric MAT in most patients is favorable, adverse outcomes of MAT have been reported, such as cardiogenic death (3%), respiratory failure (6%), or persistent arrhythmia (7%), due to delayed diagnosis and poorly controlled MAT. Previous studies demonstrated that pediatric MAT is associated with multiple enhanced automatic lesions located in the atrium or abnormal automaticity of a single lesion located in the pulmonary veins via multiple pathways to trigger electrical activity. Recent studies indicated that pediatric MAT is associated with the formation of a re-entry loop, abnormal automaticity, and triggering activity. The occurrence of pediatric MAT is affected by gestational disease, congenital heart disease, post-cardiac surgery, pulmonary hypertension, and infectious diseases, which promote MAT via inflammation, redistribution of the autonomic nervous system, and abnormal ion channels. However, the pathogenesis of MAT needs to be explored. This review is aimed to summarize and analyze the pathogenesis in pediatric MAT.

LncRNA ROR promotes NLRP3-mediated cardiomyocyte pyroptosis by upregulating FOXP1 via interactions with PTBP1.

OBJECTIVE: The purpose of this design was to explore the specific role and related mechanism of long noncoding RNA (lncRNA) regulators of reprogramming (ROR) in viral myocarditis (VMC). METHODS: AC16 cells were infected with coxsackievirus B3 (CVB3) to establish a VMC cell model in vitro. The release of interleukin (IL)-1ß and IL-18 was evaluated by enzyme-linked immunosorbent assay (ELISA). Gene expression was calculated using quantitative real-time (qRT)-PCR. Cell pyroptosis was determined by flow cytometry and Western blot assays. Cell counting Kit-8 (CCK-8) detected cell viability. The molecular associations were verified by employing RNA immunoprecipitation (RIP), RNA pulldown and chromatin immunoprecipitation (ChIP) assays. RESULTS: The lncRNA ROR was more highly expressed in CVB3 virus-infected AC16 cells than in controls. Knockdown of ROR markedly rescued cell viability and reduced the release of IL-1ß and IL-18, cell pyroptosis and pyroptotic proteins such as NLRP3, ASC and cleaved caspase 1. Mechanistically, ROR destroyed the mRNA stability of Forkhead Box P Factor 1 (FOXP1) by binding polypyrimidine tract binding protein 1 (PTBP1). FOXP1 repressed the transcription of NLRP3 by directly interacting with its promoter. Importantly, coinhibition of FOXP1 impeded the protective role of ROR silencing in CVB3-infected AC16 cells. CONCLUSION: In conclusion, these findings elucidated that ROR knockdown inhibited CVB3-induced cardiomyocyte inflammation and NLRP3-mediated pyroptosis by regulating the PTBP1/FOXP1 axis, implying that ROR might be a new inducer in CVB3-infected VMC.

Frequent torsades de pointes in a child with novel AKAP9 mutation: A case report and literature review.

Introduction: The aim of the present study is to report the diagnosis and treatment of a rare case of frequent torsades de pointes (Tdp) in a child with a novel AKAP9 mutation. A 13-year-old girl suffered from repeated syncope and frequent Tdp. An electrocardiogram (ECG) showed frequent multisource premature ventricular contractions with the R-ON-T phenomenon. The QTc ranged from 410 to 468 ms. The genetic test indicated a heterozygous mutation, namely, c.11714T > C (p.M3905T), in the AKAP9 gene, which is a controversial gene in long QT syndrome. After treatment with propranolol, recurrent syncope occurred, and the patient received an implantable cardioverter defibrillator (ICD). Due to frequent electrical storms at home, the child was additionally treated with propafenone to prevent arrhythmia. The antitachycardia pacing (ATP) function in the ICD was turned off, and the threshold of ventricular tachycardia (VT) assessment was adjusted from 180 beats/min to 200 beats/min. The patient was followed up for 12 months without malignant arrhythmia and electric shock. Conclusion: Genetic testing may be a useful tool to determine the origin of channelopathy, but the results should be interpreted in combination with the actual situation. Rational parameter settings for the ICD and application of antiarrhythmic drugs can reduce the mortality rates of children.

A three-dimensional printed model in preoperative consent for ventricular septal defect repair.

BACKGROUND: The 3D printing technology in congenital cardiac surgery has been widely utilized to improve patients' understanding of their disease. However, there has been no randomized controlled study on its usefulness in surgical consent for congenital heart disease repair. METHODS: A randomized controlled study was performed during consent process in which guardians of candidates for ventricular septal defect repair were given detailed explanation of the anatomy, indication for surgery and potential complication and risks using 3D print ventricular septal defect model (n = 20) versus a conventional 2D diagram (n = 20). A questionnaire was finished by each guardian of the patients. Data collected from questionnaires as well as medical records were statistically analyzed. RESULTS: Statistically significant improvements in ratings of understanding of ventricular septal defect anatomy (p = 0.02), and of the surgical procedure and potential complications (p = 0.02) were noted in the group that used the 3D model, though there was no difference in overall ratings of the consent process (p = 0.09). There was no difference in questionnaire score between subjects with different education levels. The clinical outcomes, as represented by the duration of intensive care unit stay, intubation duration was comparable between the two groups. CONCLUSIONS: The results indicated that it was an effective tool which may be used to consent for congenital heart surgery. Different education levels do not affect guardians' understanding in consent. The impact of 3D printing used in this scenario on long term outcomes remains to be defined.

Integrated analysis of m6A mRNA methylation in rats with monocrotaline-induced pulmonary arterial hypertension.

BACKGROUND: N6-methyladenosine (m6A) modification is one of the most common chemical modifications of eukaryotic mRNAs, which play an important role in tumors and cardiovascular disease through regulating mRNA stability, splicing and translation. However, the changes of m6A mRNA and m6A-related enzymes in pulmonary arterial hypertension (PAH) remain largely unexplored. METHODS: MeRIP-seq was used to identify m6A methylation in lung tissues from control and MCT-PAH rats. Western blot and immunofluorescence were used to evaluate expression of m6A-related enzymes. RESULTS: Compared with control group, m6A methylation was mainly increased in lung tissues from MCT-PAH rats. The up-methylated coding genes in MCT-PAH rats were primarily enriched in processes associated with inflammation, glycolysis, ECM-receptor interaction and PDGF signal pathway, while genes with down-methylation were enriched in processes associated with TGF-ß family receptor members. The expression of FTO and ALKBH5 downregulated, METTL3 and YTHDF1 increased and other methylation modification-related proteins was not significantly changed in MCT-PAH rats lung tissues. Immunofluorescence indicated that expression of FTO decreased and YTHDF1 increased in small pulmonary arteries of MCT-PAH rats. CONCLUSION: m6A levels and the expression of methylation-related enzymes were altered in PAH rats, in which FTO and YTHDF1 may play a crucial role in m6A modification.

CD38: A Potential Therapeutic Target in Cardiovascular Disease.

Substantial research has demonstrated the association between cardiovascular disease and the dysregulation of intracellular calcium, ageing, reduction in nicotinamide adenine dinucleotide NAD+ content, and decrease in sirtuin activity. CD38, which comprises the soluble type, type II, and type III, is the main NADase in mammals. This molecule catalyses the production of cyclic adenosine diphosphate ribose (cADPR), nicotinic acid adenine dinucleotide phosphate (NAADP), and adenosine diphosphate ribose (ADPR), which stimulate the release of Ca2+, accompanied by NAD+ consumption and decreased sirtuin activity. Therefore, the relationship between cardiovascular disease and CD38 has been attracting increased attention. In this review, we summarize the structure, regulation, function, targeted drug development, and current research on CD38 in the cardiac context. More importantly, we provide original views about the as yet elusive mechanisms of CD38 action in certain cardiovascular disease models. Based on our review, we predict that CD38 may serve as a novel therapeutic target in cardiovascular disease in the future.

Red blood cell transfusion threshold after pediatric cardiac surgery: A systematic review and meta-analysis.

BACKGROUND: Restrictive red blood cell transfusion strategy is implemented to minimize risk following allogeneic blood transfusion in adult cardiac surgery. However, it is still unclear if it can be applied to pediatric cardiac patients. The purpose of this systematic review and meta-analysis was to determine the effect of postoperative restrictive transfusion thresholds on clinical outcomes based on up-to-date results of randomized controlled trials (RCTs) and observational studies in pediatric cardiac surgery. METHOD: We searched for RCTs and observational studies in the following databases: the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and ClinicalTrials.gov from their inception to October 26, 2017. We also searched reference lists of published guidelines, reviews, and relevant articles, as well as conference proceedings. No language restrictions were applied and no observational study met the inclusion criteria. RESULTS: Four RCTs on cardiac surgery involving 454 patients were included. There were no differences in the pooled fixed effects of intensive care unit (ICU) stay between the liberal and restrictive transfusion thresholds (standardized mean difference SMD, 0.007; 95% confidence interval CI, -0.18-0.19; P = .94). There were also no differences in the length of hospital stay (SMD, -0.062; 95% CI, -0.28-0.15; P = .57), ventilation duration (SMD, -0.015; 95% CI, -0.25-0.22; P = .90), mean arterial lactate level (SMD, 0.071; 95% CI, -0.22-0.36; P = .63), and mortality (risk ratio, 0.49; 95% CI, 0.13-1.94; P = .31). There was no inter-trial heterogeneity for any pooled analysis. Publication bias was tested using Egger, Begg, or the trim-and-fill test, and the results indicated no significant publication bias. CONCLUSION: Evidence from RCTs in pediatric cardiac surgery, though limited, showed non-inferiority of restrictive thresholds over liberal thresholds in length of ICU stay and other outcomes following red blood cell transfusion. Further high-quality RCTs are necessary to confirm the findings.

Atrioventricular reentrant tachycardia in a child with tricuspid atresia: A case report of catheter ablation.

RATIONALE: Atrioventricular reentrant tachycardia (AVRT) is the most common supraventricular tachycardia occurring in children. However, in complex congenital heart disease patients with a different heart anatomy and conduction system morphology, accessory pathway modification may be particularly challenging because of distortion of typical anatomic landmarks. PATIENT CONCERNS: A 10-year-old boy with tricuspid atresia and history of bidirectional Glenn operation had recurrent chest distress and palpitation for 3 months. He had multiple hospitalizations for narrow-QRS tachycardia with poor hemodynamic tolerance, despite the use of adenosine and amiodarone. DIAGNOSES: AVRT. Tricuspid atresia with secundum atrial septal defect, large ventricular septal defect, and right ventricular outflow tract stenosis. INTERVENTIONS: Cardiac catheterization, electrophysiological examination, and ablation. OUTCOMES: The child has not had a recurrent AVRT during 6 months of follow-up and is waiting for Fontan operation. LESSONS: Since there is an increased risk of accessory pathways in patients with tricuspid atresia, all these patients should be checked before the Fontan operation to exclude congenital accessory pathways.

Folate-conjugated nanobubbles selectively target and kill cancer cells via ultrasound-triggered intracellular explosion.

With the rapid development of cancer-targeted nanotechnology, a variety of nanoparticle-based drug delivery systems have clinically been employed in cancer therapy. However, multidrug resistance significantly impacts the therapeutic efficacy. Physical non-drug therapy has emerged as a new and promising strategy. This study aimed to determine whether novel folate-nanobubbles (F-NBs), combined with therapeutic ultrasound (US), could act as a safe and effective physical targeted cancer therapy. Using folate-conjugated N-palmitoyl chitosan (F-PLCS), we developed novel F-NBs and characterised their physicochemical properties, internalization mechanism, targeting ability, therapeutic effects, and killing mechanism. The results showed that the novel F-NBs selectively accumulated in FR-positive endothelial cells and tumour cells via FR coupled with clathrin- and caveolin-mediated endocytosis in vitro and in vivo. In addition, the F-NBs killed target cells by an intracellular explosion under US irradiation. Hoechst/PI staining demonstrated that apoptosis and necrosis accounted for a large proportion of cell death in vivo. F-NBs combined with US therapy significantly inhibited tumour growth and improved the overall survival of tumour-bearing mice. Under US irradiation, the novel F-NBs selectively killed FR-positive tumour cells in vitro and in vivo via intracellular explosion and therefore is a promising alternative for targeted cancer treatment.

An incidental encounter of a rare high take-off right coronary artery: A case report.

RATIONALE: High take-off of the coronary arteries is a rare cardiac anatomic anomaly, which may occur independently or with other congenital heart defects. In the clinical setting, it is noteworthy as a cause of sudden cardiac death. Further, it is vital to identify such anomalies to avoid intraoperative catastrophes in surgeries for congenital heart defects. PATIENT CONCERNS: A II/6 systolic heart murmur on physical examination was incidentally found in a 9-year-old boy; he was confirmed to have a secundum-type atrial septal defect on echocardiography. He was referred to our institution for elective surgery. DIAGNOSES: The preoperative echocardiogram confirmed the presence of an atrial septal defect, and during the surgical procedure, a high take-off right coronary artery was found. INTERVENTIONS: The atrial septal defect was closed surgically, and care was taken to avoid clamping the anomalous right coronary artery when placing the aortic cross-clamp. OUTCOMES: Postoperative echocardiogram verified the presence of the high take-off right coronary artery and a satisfactory repair of the atrial septal defect. The postoperative course was uneventful, and the patient was discharged on postoperative day 5. LESSONS: This case suggests that it is critical to perform echocardiography to assess the anatomy of the coronary arteries, especially in pediatric cardiac patients. In addition, multi-detector computed tomography may be considered if appropriate. Care should be taken to assess the coronary anatomy for anomalies during interventional therapy or surgery, especially in congenital cases.

PDGF Promotes the Warburg Effect in Pulmonary Arterial Smooth Muscle Cells via Activation of the PI3K/AKT/mTOR/HIF-1α Signaling Pathway.

BACKGROUND/AIMS: The enhanced proliferation of pulmonary arterial smooth muscle cells (PASMCs) is a central pathological component in pulmonary arterial hypertension (PAH). Both the Warburg effect and platelet-derived growth factor (PDGF) are involved in the proliferation of PASMCs. However, the mechanism underlying the crosstalk between the Warburg effect and PDGF during PASMC proliferation is still unknown. We hypothesized that PDGF promotes the Warburg effect via activating the phosphatidylinositol 3-kinase (PI3K) signaling pathway and hypoxia-inducible factor 1-α (HIF-1α) in proliferative PASMCs. METHODS: PASMCs were derived from pulmonary arteries of SD rats; cell viability, the presence of metabolites, and metabolic enzyme activities assay were determined by MTT assays, kit assays and western blot analysis, respectively. RESULTS: PDGF promoted PASMC proliferation in a dose- and time-dependent manner, accompanied by an enhanced Warburg effect. Treatment with PDGFR antagonists, Warburg effect inhibitor and PDK1 inhibitor significantly inhibited PI3K signaling activation, HIF-1α expression and PASMC proliferation induced by PDGF, respectively. Furthermore, treatment with PI3K signaling pathway inhibitors remarkably suppressed PDGF-induced PASMC proliferation and the Warburg effect. CONCLUSION: microplate reader (Biotek, Winooski The Warburg effect plays a critical role in PDGF-induced PASMC proliferation and is mediated by activation of the PI3K signaling pathway and HIF-1α.

Molecular targets of the Warburg effect and inflammatory cytokines in the pathogenesis of pulmonary artery hypertension.

Pulmonary arterial hypertension (PAH) is a progressive vascular disease characterized by increased pulmonary arterial pressure and vasoconstriction and structural remolding of pulmonary arterioles. Recent clinical and experimental studies have discovered the relationship between metabolic alterations and the pathogenesis of PAH. The primary metabolic alteration, previously demonstrated in various cancers, is a gradual change in energy generated from complete aerobic cellular respiration to from solely "aerobic glycolysis," termed the "Warburg effect." Understanding the Warburg effect of metabolic dysregulation and its interaction with inflammatory mechanisms in the pathogenesis of PAH has provided a valuable explanation of this disease and has guided formulation of new clinical treatments at the molecular level.

Cor triatriatum sinister: a rare underlying cause of pulmonary hemosiderosis.

Pulmonary hemosiderosis is a disorder with unknown cause and characterized by hemosiderin appreciation in alveolar interstitium from decomposed hemoglobin following alveolar capillary bleeding, which finally leads to pulmonary fibrosis. It can be divided into primary and secondary types in terms of its etiology. While primary types are related to autoimmunity, secondary types can be associated with cardiovascular and pulmonary causes such as mitral stenosis leading to pulmonary congestion. We report a case of cor triatriatum sinister in a child who presented with hemoptysis as a main clinical manifestation and had been previously diagnosed with idiopathic pulmonary hemosiderosis. Based on clinical signs and imaging examinations, we considered the hemoptysis was most likely due to cor triatriatum. The child underwent corrective surgery with uneventful recovery. The hemoptysis has not recurred any more after operation. Cardiovascular disease including cor triatriatum should be considered with regards to the etiology of pulmonary hemosiderosis.

High molecular weight chitosan derivative polymeric micelles encapsulating superparamagnetic iron oxide for tumor-targeted magnetic resonance imaging.

Magnetic resonance imaging (MRI) contrast agents based on chitosan derivatives have great potential for diagnosing diseases. However, stable tumor-targeted MRI contrast agents using micelles prepared from high molecular weight chitosan derivatives are seldom reported. In this study, we developed a novel tumor-targeted MRI vehicle via superparamagnetic iron oxide nanoparticles (SPIONs) encapsulated in self-aggregating polymeric folate-conjugated N-palmitoyl chitosan (FAPLCS) micelles. The tumor-targeting ability of FAPLCS/SPIONs was demonstrated in vitro and in vivo. The results of dynamic light scattering experiments showed that the micelles had a relatively narrow size distribution (136.60±3.90 nm) and excellent stability. FAPLCS/SPIONs showed low cytotoxicity and excellent biocompatibility in cellular toxicity tests. Both in vitro and in vivo studies demonstrated that FAPLCS/SPIONs bound specifically to folate receptor-positive HeLa cells, and that FAPLCS/SPIONs accumulated predominantly in established HeLa-derived tumors in mice. The signal intensities of T2-weighted images in established HeLa-derived tumors were reduced dramatically after intravenous micelle administration. Our study indicates that FAPLCS/SPION micelles can potentially serve as safe and effective MRI contrast agents for detecting tumors that overexpress folate receptors.

Effects of right ventricular hemodynamic burden on intraventricular flow in tetralogy of fallot: an echocardiographic contrast particle imaging velocimetry study.

BACKGROUND: The purpose of this investigation was to test the hypothesis that flow patterns in the right ventricle are abnormal in patients with repaired tetralogy of Fallot (TOF). High-resolution echocardiographic contrast particle imaging velocimetry was used to investigate rotation intensity and kinetic energy dissipation of right ventricular (RV) flow in patients with TOF compared with normal controls. METHODS: Forty-one subjects (16 with repaired TOF and varying degrees of RV dilation and 25 normal controls) underwent prospective contrast imaging using the lipid-encapsulated microbubble (Definity) on Sequoia systems. A mechanical index of 0.4, three-beat high-frame rate (>60 Hz) captures, and harmonic frequencies were used. Rotation intensity and kinetic energy dissipation of flow in the right and left ventricles were studied (Hyperflow). Ventricular volumes and ejection fractions in all subjects were derived from same-day cardiac magnetic resonance (CMR). RESULTS: Measurable planar maps were obtained for the left ventricle in 14 patients and the right ventricle in 10 patients among those with TOF and for the left ventricle in 23 controls and the right ventricle in 21 controls. Compared with controls, the TOF group had higher RV indexed end-diastolic volumes (117.8 ± 25.5 vs 88 ± 15.4 mL/m(2), P < .001) and lower RV ejection fractions (44.6 ± 3.6% vs 51.8 ± 3.6%, P < .001). Steady-streaming (heartbeat-averaged) flow rotation intensities were higher in patients with TOF for the left ventricle (0.4 ± 0.13 vs 0.29 ± 0.08, P = .012) and the right ventricle (0.53 ± 0.15 vs 0.26 ± 0.12, P < .001), whereas kinetic energy dissipation in TOF ventricles was lower (for the left ventricle, 0.51 ± 0.29 vs 1.52 ± 0.69, P < .001; for the right ventricle, 0.4 ± 0.24 vs 1.65 ± 0.91, P < .001). CONCLUSIONS: It is feasible to characterize RV and left ventricular flow parameters and planar maps in adolescents and adults with repaired TOF using echocardiographic contrast particle imaging velocimetry. Intraventricular flow patterns in the abnormal and/or enlarged right ventricle in patients with TOF differ from those in normal young adults. The rotation intensity and energy dissipation trends in this investigation suggest that they may be quantitative markers of RV and left ventricular compliance abnormalities in patients with repaired TOF. This hypothesis merits further investigation.