Development of an operator-independent method for seeding tissue-engineered vascular grafts.

The manual seeding of cells onto a biodegradable scaffold by pipetting is an effective method of cell seeding. However, the widespread use and ultimate clinical utility of this technique is limited by operator variability. This study was conducted to evaluate an operator-independent vacuum-seeding method for use in an upcoming clinical trial.

The development and translation of the tissue-engineered vascular graft.

This lecture will define the classic tissue engineering paradigm, describe cell trafficking with regard to neotissue formation, and explain the role of the host in neotissue formation.

Developmental control of endocycles and cell growth in plants.

Timely progression of the mitotic cell cycle is central for growth and development of plant organs. Many cell types in plants also enter an alternative cell cycle called the endoreduplication cycle or endocycle in which cells increase their ploidy through repeated rounds of chromosomal replication without cell divisions. The transition from the mitotic cycle into the endocycle often coincides with the initiation of cell expansion and cell differentiation, and strong correlations between final ploidy level and cell size have been reported in many plant species.

American Pediatric Surgical Association New Technology Committee review on video-assisted thoracoscopic surgery for childhood cancer.

Background/purpose: Although the use of minimally invasive surgical (MIS) techniques for children with cancer is being practiced by some, its role remains unclearly defined. The purpose of this review was to describe the current literature on MIS for thoracic and mediastinal lesions in children.

Methods: We performed a literature search for English studies that evaluated MIS techniques for biopsy or resection in children with suspected or established cancer.

Therapy-refractory gastrointestinal motility disorder in a child with c-kit mutations.

Constipation and fecal impaction are frequent and distressing complaints in pediatric gastroenterology. Especially in neurologically handicapped children, treatment of severe forms of slow-transit constipation (STC) can be difficult. In the majority of cases, STC is of unknown etiology.

Tissue-engineered vascular grafts: does cell seeding matter?

Purpose: Use of tissue-engineered vascular grafts (TEVGs) in the repair of congenital heart defects provides growth and remodeling potential. Little is known about the mechanisms involved in neovessel formation. We sought to define the role of seeded monocytes derived from bone marrow mononuclear cells (BM-MNCs) on neovessel formation.

Tissue-engineered lungs for in vivo implantation.

Because adult lung tissue has limited regeneration capacity, lung transplantation is the primary therapy for severely damaged lungs. To explore whether lung tissue can be regenerated in vitro, we treated lungs from adult rats using a procedure that removes cellular components but leaves behind a scaffold of extracellular matrix that retains the hierarchical branching structures of airways and vasculature. We then used a bioreactor to culture pulmonary epithelium and vascular endothelium on the acellular lung matrix.

Arabidopsis thaliana GYRB3 does not encode a DNA gyrase subunit.

Background: DNA topoisomerases are enzymes that control the topology of DNA in all cells. DNA gyrase is unique among the topoisomerases in that it is the only enzyme that can actively supercoil DNA using the free energy of ATP hydrolysis. Until recently gyrase was thought to be unique to bacteria, but has now been discovered in plants.

Tissue-engineered vascular grafts transform into mature blood vessels via an inflammation-mediated process of vascular remodeling.

Biodegradable scaffolds seeded with bone marrow mononuclear cells (BMCs) are the earliest tissue-engineered vascular grafts (TEVGs) to be used clinically. These TEVGs transform into living blood vessels in vivo, with an endothelial cell (EC) lining invested by smooth muscle cells (SMCs); however, the process by which this occurs is unclear. To test if the seeded BMCs differentiate into the mature vascular cells of the neovessel, we implanted an immunodeficient mouse recipient with human BMC (hBMC)-seeded scaffolds.

Mandibular aneurysmal bone cyst in a child misdiagnosed as acute osteomyelitis: a case report and a review of the literature.

The aneurysmal bone cyst is a very infrequent, benign bone lesion in children which rarely can be found at the craniofacial skeleton. Here, we describe a case presenting in the mandible as an acute swelling of the cheek, which was initially misdiagnosed as osteomyelitis resulting in a delay to definitive surgical treatment. The cause of misleading diagnosis is often owing to the rapid growth of the lesion, sometimes associated with painful soft tissue swelling indicating an infectious origin or a malignant tumor.

Late-term results of tissue-engineered vascular grafts in humans.

Objective: The development of a tissue-engineered vascular graft with the ability to grow and remodel holds promise for advancing cardiac surgery. In 2001, we began a human trial evaluating these grafts in patients with single ventricle physiology. We report the late clinical and radiologic surveillance of a patient cohort that underwent implantation of tissue-engineered vascular grafts as extracardiac cavopulmonary conduits.

Cell-seeding techniques in vascular tissue engineering.

Previous studies have demonstrated the benefits of cell seeding in the construction of tissue-engineered vascular grafts (TEVG). However, seeding methods are diverse and no method is clearly superior in either promoting seeding efficiency or improving long-term graft function. As we head into an era during which a variety of different TEVG are under investigation in clinical trials around the world, it is important to consider the regulatory issues surrounding the translation of these technologies.

The trihelix transcription factor GTL1 regulates ploidy-dependent cell growth in the Arabidopsis trichome.

Leaf trichomes in Arabidopsis thaliana develop through several distinct cellular processes, such as patterning, differentiation, and growth. Although recent studies have identified several key transcription factors as regulating early patterning and differentiation steps, it is still largely unknown how these regulatory proteins mediate subsequent trichome development, which is accompanied by rapid cell growth and branching. Here, we report a novel trichome mutation in Arabidopsis, which in contrast with previously identified mutants, increases trichome cell size without altering its overall patterning or branching.

Serum levels of gastric-acid-stimulating factors in children undergoing open heart surgery.

Purpose: Upper gastrointestinal (GI) bleeding is a feared consequence of open heart surgery in children. Increased gastric acid secretion is a known key factor in the pathogenesis of gastritis and upper intestinal ulcerations. The aim of this study is to evaluate the serum kinetics of acid-stimulating factors and associated perioperative parameters after heart surgery in children.

Tissue-engineered arterial grafts: long-term results after implantation in a small animal model.

Background: Use of prosthetic vascular grafts in pediatric vascular surgical applications is limited because of risk of infection, poor durability, potential for thromboembolic complications, and lack of growth potential. Construction of an autologous neovessel using tissue engineering technology offers the potential to create an improved vascular conduit for use in pediatric vascular applications.

Methods: Tissue-engineered vascular grafts were assembled from biodegradable tubular scaffolds fabricated from poly-L-lactic acid mesh coated with epsilon-caprolactone and L-lactide copolymer.

Novel utilization of serum in tissue decellularization.

Decellularization of native tissues is a promising technique with numerous applications in tissue engineering and regenerative medicine. However, there are various limitations of currently available decellularization methods, such as alteration of extracellular matrix mechanics and restricted use on certain tissues. This study was conducted to explore the effect of serum on the decellularization of various types of tissues.

Decreasing sports activity with increasing age? Findings from a 20-year longitudinal and cohort sequence analysis.

According to cross-sectional studies in sport science literature, decreasing sports activity with increasing age is generally assumed. In this paper, the validity of this assumption is checked by applying more effective methods of analysis, such as longitudinal and cohort sequence analyses. With the help of 20 years' worth of data records from the German SocioEconomic Panel, the development of sports activity over a lifespan is analyzed.

Deletion of Pax7 changes the tunica muscularis of the mouse esophagus from an entirely striated into a mixed phenotype.

The mechanisms responsible for the different amounts of striated muscle in mammalian esophagi are still enigmatic. A recent ultrastructural analysis in mouse esophagus pointed to a particular role of satellite cells during postnatal growth of striated muscle. The aim of this study was to investigate satellite cell development and the influence of Pax7 on this process.

Development of decellularized human umbilical arteries as small-diameter vascular grafts.

Objective: Developing a tissue-engineered small-diameter (<6mm) vascular graft for reconstructive surgery has remained a challenge for the past several decades. This study was conducted to develop a decellularized umbilical artery and to evaluate its composition, endothelial cell compatibility, mechanical properties, and in vivo stability for potential use as a small-diameter vascular graft.

Methods And Results: Human umbilical arteries were isolated and decellularized by incubation in CHAPS and sodium dodecyl sulfate buffers followed by incubation in endothelial growth media-2.

Tissue-engineered blood vessels in pediatric cardiac surgery.

Pediatric cardiovascular surgeons often encounter patients requiring surgical intervention utilizing foreign materials to repair complex lesions. However, the materials that are commonly used lack growth potential, and long-term results have revealed several material-related failures, such as stenosis, thromboembolization, calcium deposition, and risk of infection. To solve these problems, in particular for children who require the implantation of dynamic material with growth potential, we sought to develop optimal filling materials with biocompatibility and growth potential.

Effective visualization of complex vascular structures using a non-parametric vessel detection method.

The effective visualization of vascular structures is critical for diagnosis, surgical planning as well as treatment evaluation. In recent work, we have developed an algorithm for vessel detection that examines the intensity profile around each voxel in an angiographic image and determines the likelihood that any given voxel belongs to a vessel; we term this the "vesselness coefficient" of the voxel. Our results show that our algorithm works particularly well for visualizing branch points in vessels.

Tissue-engineered vascular grafts demonstrate evidence of growth and development when implanted in a juvenile animal model.

Introduction: The development of a living, autologous vascular graft with the ability to grow holds great promise for advancing the field of pediatric cardiothoracic surgery.

Objective: To evaluate the growth potential of a tissue-engineered vascular graft (TEVG) in a juvenile animal model.

Methods: Polyglycolic acid nonwoven mesh tubes (3-cm length, 1.

Initial evaluation of the use of USPIO cell labeling and noninvasive MR monitoring of human tissue-engineered vascular grafts in vivo.

This pilot study examines noninvasive MR monitoring of tissue-engineered vascular grafts (TEVGs) in vivo using cells labeled with iron oxide nanoparticles. Human aortic smooth muscle cells (hASMCs) were labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles. The labeled hASMCs, along with human aortic endothelial cells, were incorporated into eight TEVGs and were then surgically implanted as aortic interposition grafts in a C.

A non-parametric vessel detection method for complex vascular structures.

Modern medical imaging techniques enable the acquisition of in vivo high resolution images of the vascular system. Most common methods for the detection of vessels in these images, such as multiscale Hessian-based operators and matched filters, rely on the assumption that at each voxel there is a single cylinder. Such an assumption is clearly violated at the multitude of branching points that are easily observed in all, but the most focused vascular image studies.

Splenic infarction in a patient hereditary spherocytosis, protein C deficiency and acute infectious mononucleosis.

Splenic infarction is a common cause of left upper quadrant pain and must be suspected in patients with hematologic or thromboembolic conditions and signs of localized or systemic inflammation. Although several mechanisms have been proposed for splenic infarction in patients with various hematologic disorders, hereditary spherocytosis (HS) is usually not associated with an increased risk for thromboembolic events. We report a 13-year-old male with HS who was referred to our hospital with a 4-day history of fever and left upper quadrant pain.