Targeted Rapamycin Delivery via Magnetic Nanoparticles to Address Stenosis in a 3D Bioprinted in Vitro Model of Pulmonary Veins

Vascular cell overgrowth and lumen size reduction in pulmonary vein stenosis (PVS) can result in elevated PV pressure, pulmonary hypertension, cardiac failure, and death. Administration of chemotherapies such as rapamycin have shown promise by inhibiting the vascular cell proliferation; yet clinical success is limited due to complications such as restenosis and off-target effects. The lack of in vitro models to recapitulate the complex pathophysiology of PVS has hindered the identification of disease mechanisms and therapies. This study integrated 3D bioprinting, functional nanoparticles, and perfusion bioreactors to develop a novel in vitro model of PVS. Bioprinted bifurcated PV constructs are seeded with endothelial cells (ECs) and perfused, demonstrating the formation of a uniform and viable endothelium. Computational modeling identified the bifurcation point at high risk of EC overgrowth. Application of an external magnetic field enabled targeting of the rapamycin-loaded superparamagnetic iron oxide nanoparticles at the bifurcation site, leading to a significant reduction in EC proliferation with no adverse side effects. These results establish a 3D bioprinted in vitro model to study PV homeostasis and diseases, offering the potential for increased throughput, tunability, and patient specificity, to test new or more effective therapies for PVS and other vascular diseases.

Leveraging 3D Bioprinting and Photon-Counting Computed Tomography to Enable Noninvasive Quantitative Tracking of Multifunctional Tissue Engineered Constructs

3D bioprinting is revolutionizing the fields of personalized and precision medicine by enabling the manufacturing of bioartificial implants that recapitulate the structural and functional characteristics of native tissues. However, the lack of quantitative and noninvasive techniques to longitudinally track the function of implants has hampered clinical applications of bioprinted scaffolds. In this study, multimaterial 3D bioprinting, engineered nanoparticles (NPs), and spectral photon-counting computed tomography (PCCT) technologies are integrated for the aim of developing a new precision medicine approach to custom-engineer scaffolds with traceability. Multiple CT-visible hydrogel-based bioinks, containing distinct molecular (iodine and gadolinium) and NP (iodine-loaded liposome, gold, methacrylated gold (AuMA), and Gd2 O3 ) contrast agents, are used to bioprint scaffolds with varying geometries at adequate fidelity levels. In vitro release studies, together with printing fidelity, mechanical, and biocompatibility tests identified AuMA and Gd2 O3 NPs as optimal reagents to track bioprinted constructs. Spectral PCCT imaging of scaffolds in vitro and subcutaneous implants in mice enabled noninvasive material discrimination and contrast agent quantification. Together, these results establish a novel theranostic platform with high precision, tunability, throughput, and reproducibility and open new prospects for a broad range of applications in the field of precision and personalized regenerative medicine.

Cells resident to precision templated 40-µm pore scaffolds generate small extracellular vesicles that affect CD4+ T cell phenotypes through regulatory TLR4 signaling

Precision porous templated scaffolds (PTS) are a hydrogel construct of uniformly sized interconnected spherical pores that induce a pro-healing response (reducing the foreign body reaction, FBR) exclusively when the pores are 30-40µm in diameter. Our previous work demonstrated the necessity of Tregs in the maintenance of PTS pore size specific differences in CD4+ T cell phenotype. Work here characterizes the role of Tregs in the responses to implanted 40µm and 100µm PTS using WT and FoxP3+ cell (Treg) depleted mice. Proteomic analyses indicate that integrin signaling, monocytes/macrophages, cytoskeletal remodeling, inflammatory cues, and vesicule endocytosis may participate in Treg activation and the CD4+ T cell equilibrium modulated by PTS resident cell-derived small extracellular vesicles (sEVs). The role of MyD88-dependent and MyD88-independent TLR4 activation in PTS cell-derived sEV-to-T cell signaling is quantified by treating WT, TLR4ko, and MyD88ko splenic T cells with PTS cell-derived sEVs. STAT3 and mTOR are identified as mechanisms for further study for pore-size dependent PTS cell-derived sEV-to-T cell signaling. STATEMENT OF SIGNIFICANCE: Unique cell populations colonizing only within 40µm pore size PTS generate sEVs that resolve inflammation by modifying CD4+ T cell phenotypes through TLR4 signaling.

Extrusion-Based 3D Bioprinting of Adhesive Tissue Engineering Scaffolds Using Hybrid Functionalized Hydrogel Bioinks

Adhesive tissue engineering scaffolds (ATESs) have emerged as an innovative alternative means, replacing sutures and bioglues, to secure the implants onto target tissues. Relying on their intrinsic tissue adhesion characteristics, ATES systems enable minimally invasive delivery of various scaffolds. This study investigates development of the first class of 3D bioprinted ATES constructs using functionalized hydrogel bioinks. Two ATES delivery strategies, in situ printing onto the adherend versus printing and then transferring to the target surface, are tested using two bioprinting methods, embedded versus air printing. Dopamine-modified methacrylated hyaluronic acid (HAMA-Dopa) and gelatin methacrylate (GelMA) are used as the main bioink components, enabling fabrication of scaffolds with enhanced adhesion and crosslinking properties. Results demonstrate that dopamine modification improved adhesive properties of the HAMA-Dopa/GelMA constructs under various loading conditions, while maintaining their structural fidelity, stability, mechanical properties, and biocompatibility. While directly printing onto the adherend yields superior adhesive strength, embedded printing followed by transfer to the target tissue demonstrates greater potential for translational applications. Together, these results demonstrate the potential of bioprinted ATESs as off-the-shelf medical devices for diverse biomedical applications.

3D bioprinting of nanoparticle-laden hydrogel scaffolds with enhanced antibacterial and imaging properties

Biomaterial-associated microbial contaminations in biologically conducive three-dimensional (3D) tissue-engineered constructs have significantly limited the clinical applications of scaffold systems. To prevent such infections, antimicrobial biomaterials are rapidly evolving. Yet, the use of such materials in bioprinting-based approaches of scaffold fabrication has not been examined. This study introduces a new generation of bacteriostatic gelatin methacryloyl (GelMA)-based bioinks, incorporated with varying doses of antibacterial superparamagnetic iron oxide nanoparticles (SPIONs). The SPION-laden GelMA scaffolds showed significant resistance against the Staphylococcus aureus growth, while providing a contrast in magnetic resonance imaging. We simulated the bacterial contamination of cellular 3D GelMA scaffolds in vitro and demonstrated the significant effect of functionalized scaffolds in inhibiting bacterial growth, while maintaining cell viability and growth. Together, these results present a new promising class of functionalized bioinks to 3D bioprint tissue-engineered scaffold with markedly enhanced properties for the use in a variety of in vitro and clinical applications.

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Functionalized bioinks with bacteriostatic properties are developed and thoroughly characterized

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The 200 μg/mL group yielded an optimal balance of printed scaffold properties

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Incorporating nanoparticle also enabled noninvasive imaging of the bioprinted scaffold

A 3D Bioprinted in vitro Model of Neuroblastoma Recapitulates Dynamic Tumor-Endothelial Cell Interactions Contributing to Solid Tumor Aggressive Behavior

Neuroblastoma (NB) is the most common extracranial tumor in children resulting in substantial morbidity and mortality. A deeper understanding of the NB tumor microenvironment (TME) remains an area of active research but there is a lack of reliable and biomimetic experimental models. This study utilizes a 3D bioprinting approach, in combination with NB spheroids, to create an in vitro vascular model of NB for exploring the tumor function within an endothelialized microenvironment. A gelatin methacryloyl (gelMA) bioink is used to create multi-channel cubic tumor analogues with high printing fidelity and mechanical tunability. Human-derived NB spheroids and human umbilical vein endothelial cells (HUVECs) are incorporated into the biomanufactured gelMA and cocultured under static versus dynamic conditions, demonstrating high levels of survival and growth. Quantification of NB-EC integration and tumor cell migration suggested an increased aggressive behavior of NB when cultured in bioprinted endothelialized models, when cocultured with HUVECs, and also as a result of dynamic culture. This model also allowed for the assessment of metabolic, cytokine, and gene expression profiles of NB spheroids under varying TME conditions. These results establish a high throughput research enabling platform to study the TME-mediated cellular-molecular mechanisms of tumor growth, aggression, and response to therapy.

Tissue engineered drug delivery vehicles: Methods to monitor and regulate the release behavior

Tissue engineering is a rapidly evolving, multidisciplinary field that aims at generating or regenerating 3D functional tissues for in vitro disease modeling and drug screening applications or for in vivo therapies. A variety of advanced biological and engineering methods are increasingly being used to further enhance and customize the functionality of tissue engineered scaffolds. To this end, tunable drug delivery and release mechanisms are incorporated into tissue engineering modalities to promote different therapeutic processes, thus, addressing challenges faced in the clinical applications. In this review, we elaborate the mechanisms and recent developments in different drug delivery vehicles, including the quantum dots, nano/micro particles, and molecular agents. Different loading strategies to incorporate the therapeutic reagents into the scaffolding structures are explored. Further, we discuss the main mechanisms to tune and monitor/quantify the release kinetics of embedded drugs from engineered scaffolds. We also survey the current trend of drug delivery using stimuli driven biopolymer scaffolds to enable precise spatiotemporal control of the release behavior. Recent advancements, challenges facing current scaffold-based drug delivery approaches, and areas of future research are discussed.

Self-care behaviours mediate the effect of educational intervention on health-related quality of life of patients with heart failure: causal mediation analysis

Background/Introduction

Educational interventions have been developed and tested in an attempt to improve health-related quality of life (HRQOL) for patients with heart failure (HF). While some have shown satisfactory results, the mechanism of the intervention effect on HRQOL remains unclear.

Purpose

To explore whether HF knowledge, self-care behaviours, self-care maintenance, self-care confidence, or social support mediates the effect of intervention on HRQOL of patients with HF

Methods

We analysed data from a randomized controlled trial testing the effect of an educational intervention for patients with HF. The intervention group (n=60) received 1-hour single session education followed by 8-week telephone follow-ups, and the control group (n=62) received care as usual. Study variables were measured at baseline and at 3 and 6 months. Using causal mediation analysis described by Valeri & VanderWeele (2013), we explored the causal pathway between intervention allocation and HRQOL at 6 months with HF knowledge, self-care behaviours, self-care maintenance, self-care confidence, and social support measured at 3 months as potential mediators (Figure 1).

Results

Intervention allocation was significantly associated with HF knowledge, self-care behaviours, self-care maintenance, and self-care confidence at 3 months (all p<0.05), but not with social support at 3 months (p=0.57). In unadjusted models, none of the potential mediators had a significant indirect effect between intervention and HRQOL. When adjusting for age and gender, the indirect effect of self-care behaviours on 6-month HRQOL became significant (indirect effect −6.24, 95% CI: −12.88 to −1.18). When baseline values of the mediator and HRQOL were adjusted in addition to age and gender, the indirect effect of self-care behaviours remained significant (indirect effect −7.18, 95% CI: −13.48 to −2.35) and the indirect effect of self-care maintenance became significant (indirect effect −3.02, 95% CI: −7.94 to −0.07).

Conclusion

Our findings support the mediating role of self-care behaviours on the relationship between the educational intervention and HRQOL of patients with HF. In order to successfully improve HRQOL of patients with HF, educational interventions should aim to promote self-care behaviours, especially by encouraging treatment adherence and self-monitoring.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Seoul National University, College of Medicine Figure 1. Mediation model

Abstract P403: Three-dimensional Bioprinting Of Adhesive Cardiac Patch Systems

Rapid advancements in 3D bioprinting have enabled the design of functionalized bioinks to create scaffolds with robust adhesive properties. These constructs are of great interest in cardiac tissue engineering, where the integration of grafted patch with the host myocardium, through sutures, staples, or adhesives, faces risks such as bleeding, cytotoxicity, and infection. We introduce the first generation of functional adhesive bioinks that can be bioprinted through various modalities to fabricate patch structures with intrinsic adhesive properties. A dopamine-modified hyaluronic acid methacrylate (HAMA-Dopa) and gelatin methacrylate (gelMA) composite bioink is used to create the patch via air and embedded bioprinting. Constructs are crosslinked onto a collagen sheet substrate simulating the host cardiac tissue ( Figure 1A-C ).

We developed novel in vitro methods to assess adhesion properties of printed patch under shear, tension, or dynamic loading ( Figure 1C ). Our approach allowed for steady and precise application of stress to the adhesion interface. Embedded-printed HAMA-Dopa/gelMA scaffold showed significantly enhanced adhesion strength (1025 Pa) compared to gelMA (495 Pa) and HAMA (477 Pa) control groups under tension, and under shear (548 Pa vs. 234 and 239 Pa). The adhesion strength of air-printed HAMA-Dopa/gelMA constructs was markedly higher (10,128 Pa) than the embedded ones, possibly due to the more effective, in-situ crosslinking. We also investigated the dynamic adhesive properties in aqueous environment using an ex vivo beating heart model. Air-printed HAMA-Dopa/gelMA showed the greatest adhesion under wet conditions, tolerating 345,600 cycles. We further characterized printing fidelity, mechanical properties, swelling, and biocompatibility of HAMA-Dopa/gelMA constructs, demonstrating adequate functionality of this bioprinted adhesive scaffold for cardiac tissue engineering applications.

Figure 1 . Summary of workflow to develop bioprinted adhesive scaffolds. A: Embedded (top) or air (bottom) bioprinting was used to create 3D patch geometries. B: Printing fidelity assessment and optimization. C: Different adhesion mechanisms were assessed using novel customized tools and approaches to apply tensile ( C-i ), shear ( C-ii ), and dynamic ( C-iii ) loading.

3D Bioprinting of Neural Tissues

The human nervous system is a remarkably complex physiological network that is inherently challenging to study because of obstacles to acquiring primary samples. Animal models offer powerful alternatives to study nervous system development, diseases, and regenerative processes, however, they are unable to address some species-specific features of the human nervous system. In vitro models of the human nervous system have expanded in prevalence and sophistication, but still require further advances to better recapitulate microenvironmental and cellular features. The field of neural tissue engineering (TE) is rapidly adopting new technologies that enable scientists to precisely control in vitro culture conditions and to better model nervous system formation, function, and repair. 3D bioprinting is one of the major TE technologies that utilizes biocompatible hydrogels to create precisely patterned scaffolds, designed to enhance cellular responses. This review focuses on the applications of 3D bioprinting in the field of neural TE. Important design parameters are considered when bioprinting neural stem cells are discussed. The emergence of various bioprinted in vitro platforms are also reviewed for developmental and disease modeling and drug screening applications within the central and peripheral nervous systems, as well as their use as implants for in vivo regenerative therapies.

Biomechanical factors in three-dimensional tissue bioprinting

3D bioprinting techniques have shown great promise in various fields of tissue engineering and regenerative medicine. Yet, creating a tissue construct that faithfully represents the tightly regulated composition, microenvironment, and function of native tissues is still challenging. Among various factors, biomechanics of bioprinting processes play fundamental roles in determining the ultimate outcome of manufactured constructs. This review provides a comprehensive and detailed overview on various biomechanical factors involved in tissue bioprinting, including those involved in pre, during, and post printing procedures. In preprinting processes, factors including viscosity, osmotic pressure, and injectability are reviewed and their influence on cell behavior during the bioink preparation is discussed, providing a basic guidance for the selection and optimization of bioinks. In during bioprinting processes, we review the key characteristics that determine the success of tissue manufacturing, including the rheological properties and surface tension of the bioink, printing flow rate control, process-induced mechanical forces, and the in situ cross-linking mechanisms. Advanced bioprinting techniques, including embedded and multi-material printing, are explored. For post printing steps, general techniques and equipment that are used for characterizing the biomechanical properties of printed tissue constructs are reviewed. Furthermore, the biomechanical interactions between printed constructs and various tissue/cell types are elaborated for both in vitro and in vivo applications. The review is concluded with an outlook regarding the significance of biomechanical processes in tissue bioprinting, presenting future directions to address some of the key challenges faced by the bioprinting community.

Bioprintability: Physiomechanical and Biological Requirements of Materials for 3D Bioprinting Processes

Three-dimensional (3D) bioprinting is an additive manufacturing process that utilizes various biomaterials that either contain or interact with living cells and biological systems with the goal of fabricating functional tissue or organ mimics, which will be referred to as bioinks. These bioinks are typically hydrogel-based hybrid systems with many specific features and requirements. The characterizing and fine tuning of bioink properties before, during, and after printing are therefore essential in developing reproducible and stable bioprinted constructs. To date, myriad computational methods, mechanical testing, and rheological evaluations have been used to predict, measure, and optimize bioinks properties and their printability, but none are properly standardized. There is a lack of robust universal guidelines in the field for the evaluation and quantification of bioprintability. In this review, we introduced the concept of bioprintability and discussed the significant roles of various physiomechanical and biological processes in bioprinting fidelity. Furthermore, different quantitative and qualitative methodologies used to assess bioprintability will be reviewed, with a focus on the processes related to pre, during, and post printing. Establishing fully characterized, functional bioink solutions would be a big step towards the effective clinical applications of bioprinted products.

Neutral plane control by using polymer/graphene flake composites for flexible displays

PMMA/graphene composites with varying graphene content can control the modulus and thus the neutral plane of flexible displays while enhancing barrier properties.

Effect of RGO deposition on chemical and mechanical reliability of Ag nanowire flexible transparent electrode

The role of RGO in chemical and mechanical reliability was studied for Ag nanowire/RGO hybrid electrode. RGO deposition can be effective in reducing the oxidation while maintaining the superior mechanical reliability under cyclic bendings.

Abstract P4-06-15: BP1 Upregulates Twist and Induces EMT in Breast Cancer Cells

Background: We have cloned a gene, BP1, which is a member of the homeobox gene family of transcription factors. Our recent studies have shown that BP1 may play a role in breast cancer cell survival, aggressiveness and metastasis. BP1 protein (pBP1) is expressed in 80% of invasive ductal breast tumors, and is associated with estrogen receptor negativity and tumors of African American women, both associated with aggressive tumors. BP1 is also expressed in metastatic tumors, shown by immunostaining of 46 samples of inflammatory breast cancer; all cases were BP1 positive. Nine cases had metastasized, and all nine metastatic lymph nodes were BP1 positive. BP1 positive cells were observed in lymph channels and blood vessels. Here, we demonstrated BP1 induces the epithelial to mesenchymal transition (EMT), resulting in increased migratory ability. EMT, a process by which cancer cells lose their epithelial features and gain mesenchymal markers, enables tumor cells become more invasive, migratory and can lead to metastasis. Twist, a basic helix-loop-helix (bHLH) transcription factor which triggers EMT, is activated by BP1.

Materials and Methods: RNA levels of markers of EMT were verified by real-time PCR and their protein levels by Western blotting and, in some cases, by confocal microscopy. Chromatin immunoprecipitation (ChIP) was performed to verify the BP1 binding site on the Twist promoter. A scratch test was used to measure migratory ability. BP1 knockdown by siRNA transfection was also performed. Recombinant BP1 (rpBP1) was produced in E. coli.

Results: Increased expression levels of Twist were observed on microarrays after probing with RNA from MCF-7 cell lines overexpressing BP1. We demonstrated that BP1 can upregulate Twist expression in two different breast cancer cell lines, MCF-7 and Hs578T cells, by binding to the Twist promoter. BP1 upregulates mesenchymal marker expression and down-regulates epithelial marker expression, consistent with EMT. BP1 also promotes breast cancer cell migratory ability, shown by the scratch test. In addition, cells grown in medium supplemented with rpBP1 showed increased Twist expression and migration. Experiments evaluating the effects of siBP1 on EMT are underway.

Conclusions: BP1 stimulates Twist expression in MCF-7 and HS578T breast cancer cells, resulting in a more mesenchymal cell phenotype. We therefore hypothesize that BP1 induces EMT by upregulating Twist expression, and may result in metastasis. If BP1 is involved in EMT, it may be a good target for therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-06-15.

Comparison of heart failure in children with enterovirus 71 rhombencephalitis and cats with norepinephrine cardiotoxicity

The mechanism of heart failure in patients with enterovirus 71 rhombencephalitis (brain stem encephalitis) remains unknown. Our previous reports hypothesized that a catecholamine storm induced by rhombencephalitis may account for the heart failure. The aim of this study was to develop a novel feline model of norepinephrine cardiotoxicity and compare the resulting heart failure to that in children with enterovirus 71 rhombencephalitis. Nine of 75 children (12%) with enterovirus 71 rhombencephalitis (5 boys and 4 girls; age, 4-28 months; median age, 16 months) were complicated with left ventricular hypokinesia (ejection fraction, 31 +/- 9%). Six cats (weight, 3.03 +/- 0.64 kg) were administered intravenous norepinephrine 30 microg/kg/min for 3 hours. Echocardiography assessed the left ventricular diameter and function before and after the administration of norepinephrine. Pathology studies included hematoxylin and eosin stain and in situ terminal deoxyribonucleotidyl transferase-mediated dUTP nick end-labeling assay. In the feline model, norepinephrine induced significant left ventricular dilatation (end diastolic diameter from 1.18 +/- 0.19 to 1.62 +/- 0.22 cm, p = 0.001; endsystolic diameter from 0.54 +/- 0.09 to 1.36 +/- 0.32 cm, p = < 0.001) and hypokinesia (ejection fraction from 87.5 +/- 4.1 to 35.2 +/- 16.3%, p = 0.001). Heart specimens from 4 patients and six cats showed similar pathology findings, including myocardial hemorrhage, cardiomyocyte apoptosis, and coagulative myocytolysis, which is characterized by sarcoplasmic coagulation, granulation, vacuolization, myofibrillar waving, and disruption. Both groups showed no significant inflammatory reaction. In conclusion, heart failure in patients with enterovirus 71 rhombencephalitis is similar to that in cats with norepinephrine cardiotoxicity. Norepinephrine cardiotoxicity may play a role in the pathogenesis of heart failure in enterovirus 71 rhombencephalitis.

Optimizing a canine survival model of orthotopic lung transplantation

INTRODUCTION

While acute models of orthotopic lung transplantation have been described in dogs, the technical considerations of developing a survival model in this species have not been elaborated. Herein, we describe optimization of a canine survival model of orthotopic lung transplantation.

METHODS

Protocols of orthotopic left lung transplantation and single lung ventilation were established in acute experiments (n=9). Four dogs, serving as controls, received autologous, orthotopic lung transplants. Allogeneic transplants were performed in 16 DLA-identical and 16 DLA-mismatched unrelated recipient dogs. Selective right lung ventilation was utilized in all animals. A Malecot tube was left in the pleural space connected to a Heimlich valve for up to 24 hours. To date, animals have been followed up to 24 months by chest radiography, pulmonary function tests, bronchoscopy with lavage, and open biopsies.

RESULTS

Long-term survival was achieved in 34/36 animals. Two recipients died intraoperatively secondary to cardiac arrest. All animals were extubated on the operating table, and in all cases the chest tube was removed within 24 hours. Major complications included thrombosis of the pulmonary artery and subcritical stenosis of bronchial anastamosis. One recipient underwent successful treatment of a small bowel intussusception.

CONCLUSIONS

We report our experience in developing a survival canine model of orthotopic single lung transplantation. While short-term survival following canine lung transplantation is achievable, we report particular considerations that facilitate animal comfort, early extubation, and lung reexpansion in the immediate postoperative period, further optimizing use of this species for experimental modeling of long-term complications after lung transplantation.

Effect of mycelial culture broth of Ganoderma lucidum on the growth characteristics of human cell lines

Two types of purified samples, water-soluble (sample A; M. W, 1.2 x 10(6) dalton) and water-insoluble (sample C; M. W., 1.0 x 10(6) dalton) samples, were obtained through consecutive separation processes from the culture broth of Ganoderma lucidia mycelium. It was found that both samples from the culture broth were very effective in inhibiting the growth of several human cancer cell lines, having a 93-85% growth inhibition on Hep3B, AGS and A549 with the least cytotoxicity on the normal human lung cell line, WRL68 of less than 25% the highest supplementation concentration of 1.0 mg/l. In general, the sample C showed greater inhibition of cancer cell growth than the sample A. The same trend was also observed in antimutagenicity using the Chinese hamster ovary cell line (CHO test) or Salmonella typhimurium (Ames test). The CHO test showed that sample C had higher antimutagenicity on mutagens 4NQO or MMNG than sample A (approximately 40% vs approximately 25%). The percentage of antimutagenicity from the Ames test was lower than that from the CHO test, possibly due to the difference in the sensitivity of mutagens. The water-insoluble sample greatly enhanced the growth of the human T cell line (H9) up to 1 x 10(5) with sample supplementation at 1.0 mg/l concentration from 4.3 x 10(4) without sample supplementation as well as improved the secretion level of both IL-6 and TNF-alpha up to 100 pg/ml from approximately 40 pg/ml without sample supplementation. The kinetics of response to the immune cell growth was illustrated by the response time obtained when the sample concentration was increased. The water-insoluble sample can be used for effectively treating cancer in that it accelerated apoptosis of human carcinoma cells up to 70% compared to less than 50% for the control. The sample also increased the differentiation ratio of HL-60 cells up to 58% after four days of cultivation, compared to 18% in the case of no sample supplementation. These results can be used in implying that the insoluble part of G. lucidium mycelium culture broth must be related to controlling signal transduction, resulting in the regulation of cancer cell growth.

Transcatheter closure of a large patent ductus arteriosus in a young child using the Amplatzer duct occluder

The Amplatzer duct occluder (ADO) provides a safe and effective therapy for patients with moderate- to large-sized patent ductus arteriosus (PDA), but there have been few reports of transcatheter closure of very large PDAs in young children and infants. We report a successful transcatheter closure of a very large PDA, 10.5 mm in diameter at the narrowest point, with a 14/12-mm ADO. To our knowledge, this is the largest PDA ever closed by an interventional method in such a young child.

Contribution of genetic factors to neonatal transient hypothyroidism

BACKGROUND

The causes of neonatal transient hypothyroidism (NTH) remain incompletely understood. Whether it is influenced by genetic background is rarely discussed and remains unproven. A defect in thyroid peroxidase is a common cause of dyshormonogenesis of the thyroid gland in Taiwanese, with a novel mutation (2268insT) present in nearly 90% of alleles studied.

OBJECTIVE

To determine if the presence of this common mutation is associated with NTH in Taiwan.

METHODS

A mismatched primer was designed and used for this specific 2268insT mutation to screen 1000 normal babies and 260 babies with confirmed NTH.

RESULTS

The carrier rate for 2268insT in normal babies (1/200) was significantly lower than in babies with NTH (1/13; p<0.0001).

CONCLUSIONS

The results strongly suggest that the presence of this thyroid peroxidase mutation contributes to the development of NTH. Likely pathogenetic explanations include the effect of the stress of extrauterine adaptation during labour on an immature pituitary-thyroid axis in genetically predisposed individuals, combined with environmental triggers such as iodine deficiency, perinatal iodine exposure, and/or goitrogen contamination.

Stimulation of asiaticoside accumulation in the whole plant cultures of Centella asiatica (L.) urban by elicitors

The effects of a number of different elicitors on asiaticoside production in whole plant cultures of Centella asiatica were studied, including yeast extract, CdCl(2), CuCl(2) and methyl jasmonate (MJ). Only MJ and yeast extract stimulated asiaticoside production--1.53 and 1.41-fold, respectively. Maximum asiaticoside production was achieved following treatment with 0.1 mM MJ (116.8 mg/l). The highest asiaticoside production (342.72 mg/l) was obtained after 36 days of elicitation in cultures treated with 0.1 mM MJ and 0.025 mg/l 1-phenyl-3-(1,2,3-thidiazol-5-yl)urea (TDZ). Interestingly, MJ not only stimulated the production of asiaticoside but also had an important role in the senescence of C. asiatica. Although asiaticoside content did not change when TDZ was added to medium containing an elicitor, TDZ did increase shoot growth of C. asiatica. We discuss the interactive roles of MJ and TDZ in secondary metabolic production and biomass in whole plants of C. asiatica.

Contributions of bone maturation measurements to the differential diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism

AIM

To a) evaluate the contribution of bone maturation in the diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism in full-term newborns, and b) use bone maturation to test the hypothesis that neonatal transient hypothyroidism is perinatal in onset.

MATERIALS AND METHODS

The study included 20 patients with dyshormonogenetic and 43 with transient hypothyroidism. Thyroid function and measurements of the distal femoral epiphysis area, obtained at the time of first confirmatory diagnosis, were compared between the two groups. The epiphysis area in two control groups with normal thyroid function was also measured and compared with that in patients with transient hypothyroidism, at age 1-3 d (control A), or at the age when normal thyroid function was confirmed (control B).

RESULTS

Mean epiphysis area was 0.04 cm2 in patients with dyshormonogenetic versus 0.22 cm2 in patients with transient hypothyroidism (p < 0.0001). An area <0.05 cm2 was limited to patients with dyshormonogenetic hypothyroidism. Conversely, a normal area (>0.2 cm2) was only observed in patients with transient hypothyroidism. Mean epiphysis areas in control A (0.20 cm2) and in patients with transient hypothyroidism were similar (p = 0.37), consistent with perinatal onset of transient hypothyroidism. Mean epiphysis area in control B (0.31 cm2) was significantly greater than in patients with transient hypothyroidism (p < 0.01).

CONCLUSIONS

A short duration of hypothyroidism can significantly delay bone maturation. Examination of bone maturation at initial confirmatory evaluation yields important information pertaining to congenital hypothyroidism, not only to predict intellectual development, but also to evaluate the risk of dyshormonogenetic hypothyroidism.

Cardiac complications of enterovirus rhombencephalitis

BACKGROUND

Epidemics of enterovirus 71 infection have caused the death of many children throughout the world. Rhombencephalitis, brain stem encephalitis, and heart failure were present in all of the fatal cases. However, no evidence of myocarditis was noted in the heart specimens, and the mechanism of heart failure remains unknown.

AIMS

To characterise the presentation of cardiac complications in children with enterovirus rhombencephalitis and discuss its pathogenesis.

METHODS

Ninety one consecutive patients with enterovirus rhombencephalitis underwent echocardiography. Of these, 17 patients (nine male, eight female; median age 14 months, range 4-57 months) with left ventricular dysfunction were studied.

RESULTS

Tachycardia was noted in all patients and systemic hypertension in 12. Muscle-brain fraction of creatine kinase was >5% in 14 patients. Plasma norepinephrine and epinephrine levels were significantly raised in the three patients in whom these were analysed. Electrocardiographic abnormalities were noted in eight patients. Pulmonary oedema was complicated in 15 patients. The initial ejection fraction of the left ventricle was 22-58% (mean 37%, SD 11%). All patients deteriorated to hypotensive shock within 12 hours and 13 died. Heart specimens from seven patients showed no evidence of myocarditis, but significant coagulative myocytolysis, myofibrillar degeneration, and cardiomyocyte apoptosis were observed.

CONCLUSIONS

Acute heart failure was noted in 19% of patients with enterovirus rhombencephalitis, which had a fatality rate of 77%. It was not caused by myocarditis but possibly by neurogenic cardiac damage.

Separation of benzene, toluene, ethylbenzene, and xylenes by micellar electrokinetic capillary chromatography

The use of sodium dodecyl sulfate, urea, beta-cyclodextrin, and methanol as additives to the electrophoretic medium containing a Na2HPO4-boric acid buffer in the micellar electrokinetic capillary chromatography of benzene, toluene, ethylbenzene, and three isomers of xylene (collectively known as BTEX) was investigated. The results showed that with the addition of sodium dodecyl sulfate only, higher selectivity and sensitivity and shorter migration time could be achieved, which consequently resulted in better separation of BTEX studied. For this buffer system, good linearity (R2>0.99) was found over the range of 5 to 500 microg ml(-1) for individual BTEX compound and separation time of less than 5 min for BTEX was possible.

Poor agreement between dipyridamole-stress technetium-99m-tetrofosmin myocardial perfusion single photon emission computed tomography and two-dimensional echocardiography in Kawasaki disease

To establish a noninvasive diagnostic method for early assessment of cardiac involvement in Kawasaki disease (KD), 28 children with KD were included in this study. Two-dimensional echocardiography (2D-Echo) to detect the aneurysms of coronary arteries (CA), as well as rest and dipyridamole-stress technetium-99m tetrofosmin (Tc-TF) myocardial perfusion single photon emission computed tomography (SPECT) to detect abnormal myocardial perfusion were performed in all of the 28 children with KD and to compare each other. The results showed that (1). 42.9% of cases had no aneurysm and 57.1% had significant aneurysms detected by 2D-Echo; (2). 42.9% of cases had normal perfusion and 57.1% of cases had abnormal myocardial perfusion assessed by Tc-TF myocardial perfusion SPECT; (3). 25.0% of cases showed both normal 2D-Echo and Tc-TF myocardial perfusion SPECT findings and 39.3% of cases showed both abnormal 2D-Echo and Tc-TF myocardial perfusion SPECT findings; and (4). there was poor agreement between 2D-Echo and Tc-TF myocardial perfusion SPECT findings (P>0.05). We concluded that poor agreement exists between aneurysms and abnormal myocardial perfusion detected by 2D-Echo and Tc-TF myocardial perfusion SPECT findings in patients with KD.

Clinical and electrophysiological characteristics in children with atrioventricular nodal reentrant tachycardia

Atrioventricular (AV) nodal reentrant tachycardia is one of the most common supraventricular tachycardias in childhood. However, information about AV nodal reentrant tachycardia in childhood is limited, especially about the variant and multiple forms. The purpose of this retrospective study was to investigate the clinical and electrophysiological characteristics in pediatric patients with AV nodal reentrant tachycardia. Forty-eight pediatric patients with AV nodal reentrant tachycardia were included (ages 11-18 years; 25 males and 23 females). The age of onset and duration of symptoms were significantly younger and shorter in pediatric patients, respectively. A higher incidence of antegrade dual AV nodal pathways was found in adult patients than pediatric patients (72.9 vs 52.1% p = 0.003). Both antegrade and retrograde slow pathway functions were better in pediatric than adult patients. There was no significant difference between children and adults in the occurrence of variant and multiple forms of AV nodal reentrant tachycardia. This study demonstrated that pediatric patients have different electrophysiologic characteristics from those of adult patients.

Nonmyeloablative allogeneic bone marrow transplantation for orbital granulocytic sarcoma associated with t(8;21)(q22;q22) in acute myeloid leukemia

We report a nonmyeloablative allogeneic bone marrow transplant (allo-BMT) from an HLA-matched unrelated donor in a case of acute myeloid leukemia (AML), M2 with t(8;21)(q22;q22) and the presence of orbital granulocytic sarcoma (GS), who had residual tumor after conventional chemotherapy. The course of BMT was well tolerated, with no major procedure-related toxicity. The residual orbital GS regressed completely 4 months after BMT. She is currently 19 months post BMT, disease-free. To our knowledge, this is the first reported pediatric patient with AML, GS and t(8;21)(q22;q22) who received a nonmyeloablative allo-BMT.

Breath hydrogen responses in infants using lactose-rice formula and regular lactose formula

Starch thickened infant formulas have been shown to relieve regurgitation and increase caloric retention. We compared the completeness of digestion of the carbohydrates in lactose-rice formula (study formula) with routine infant formula in infants with GER. A prospective open study of 30 normal, well-nourished infants with simple regurgitation was conducted. The clinical history on regurgitation, stool pattern and baseline breath hydrogen (bH2) test were obtained at entry, with the infants still using their original routine infant formula, and after a wash out period of 7 days, during which they were fed only with study formula. Analysis of bH2 results showed lower levels of bH2 at 1, 2 and 3 hours with study formula compared with the original formula at the 2nd and 3rd hour (p<0.05). The effectiveness of the study formula in managing GER was demonstrated by the fact that 26 out of 30 had either "some improvement" or a "good response." Hardening of the stool pattern was reported in 13 of the 30 infants after 1 week of study formula. The mean of peak bH2 in study formula fed subjects with formed and firm/hard stool was significantly lower than in those with soft and pasty stool. In conclusion, this study has shown the effectiveness of rice thickened infant formulas in managing infants with GER. Rice-starch has an additional advantage of ease of digestion. The hardening of stool pattern was also frequently observed.

Intravenous gamma-globulin therapy in myocarditis complicated with complete heart block: Report of one case

Myocarditis complicated with complete heart block is rare in childhood. We report a case of 4-year-old child presented with complete heart block which may have been caused by Mycoplasma pneumoniae. Under emergent temporal pacing, patient experienced cardiogenic shock with pulmonary edema eventually. The cardiopulmonary function was improved with atrial rhythm at the 6th hour later after intravenous infusion with high-dose gamma-globulin (IVIG). The IVIG therapy may have immunomodulatory effects and serve as a potential adjunctive therapy for fulminant myocarditis.

Families of Chinese children with malignancy: the factors impact on mother's anxiety

This study examines the impact of the stress experienced by mothers during a child's cancer treatment. A descriptive correlation study has been designed to examine the relationships between uncertainty, sense of mastery, boundary ambiguity, and anxiety. The sample consists of 100 mothers recruited in two teaching hospitals in Taiwan. The sense of mastery was found to act as a mediator between uncertainty and anxiety, whereas uncertainty was a good predictor of boundary ambiguity. The first 2 months of treatment and the incidence of cancer recurrence represented a significant special experience for mothers. Nursing intervention to improve the mothers' sense of mastery and to assist families in establishing functional patterns of parent-child interaction is discussed.

Absence of mutations in human ubiquitin fusion-degradation protein gene in tetralogy of Fallot

Congenital defects in human chromosome 22q11 deletion syndromes are associated with the 3rd and 4th pharyngeal pouch during fetal development. In the cardiovascular system, these disorders are usually apparent as conotruncal heart defects and aortic arch anomalies. UFD1L, a gene that is downregulated in dHAND-deficient mice, expressed in the mouse embryo at the branchial arch and mapped to human chromosome 22q11, has recently been strongly suspected to be responsible for the phenotypes expressed in 22q11 deletion syndromes. Its putative causal role in relevant congenital cardiovascular malformations was studied by gene dosage analysis, mutation screening and sequence analyses. Sixty cases of tetralogy of Fallot with no detectable chromosome deletion at 22q11 or 10p13 were examined, including 51 cases of simple tetralogy of Fallot, and 9 cases of tetralogy of Fallot with pulmonary atresia. None of these patients revealed deletion limited to a portion of the UFD1L gene. Although mobility shift was found by heteroduplex analysis in 24 cases at exon 4 and flanking sequences, further sequence analysis demonstrated only two silent nucleotide variations and a single nucleotide polymorphism in intron 4. Our data suggest that, although the UFD1L gene is mapped to 22q11 and is expressed during early murine development at both cardiac and cranial neural crests, it is not responsible for the majority of tetralogy of Fallot cases in humans.

Chromosome 22q11 microdeletion in conotruncal heart defects: clinical presentation, parental origin and de novo mutations

Using genotype analysis and multiplex quantitative polymerase chain reaction (PCR), chromosome 22q11 deletions were examined in 252 patients with syndromic or isolated conotruncal heart defect. Of these patients, 19 (7.5%) were found to be hemizygous for chromosome 22q11. Parental origin of the deleted chromosome was determined in 16 cases: one patient (6.3%) inherited a deleted chromosome 22 from his mother; all the others (93.7%) consisted of de novo mutations. One-third (5/15) of the de novo 22q11 deletions were of paternal origin and the remainder derived maternally. These results lend further support to our current knowledge of chromosome 22q11 microdeletion syndromes and their implications for the genetic counseling of individuals diagnosed with conotruncal heart defects. Possible mechanisms for gender-biased parental origin are discussed.