Abstract:The importance of scaffold biomaterials has been emphasized for in vitro culture of tissue-engineered cartilage in a three-dimensional (3D) environment. In this study, we examined the feasibility of fibrin glue, mixed with hyaluronic acid (HA) as a composite scaffold. Fibrin glue has been a useful cell delivery matrix for cartilage tissue engineering and HA is a key component of normal articular cartilage. Our hypothesis is that compared to fibrin itself, a fibrin/HA composite can have significantly enhanced properties, due mainly to the added benefits of HA in the matrix. Pieces of cartilage were isolated from rabbit knees and the chondrocytes were harvested through enzymatic digestion. Both fibrin and fibrin/HA composite were prepared and subsequently implanted in nude mice (n = 9, each group) for 1, 2, and 4 weeks, respectively. The retrieved specimens were then analyzed and the results were compared. Cartilage-like tissue formation was detected earlier with fibrin/HA specimens. They produced significantly higher amounts of the extracellular matrix (ECM) molecules, GAG, and collagen at each time point than those in fibrin. Interestingly, the fibrin/HA composite was also competent in maintaining its initial size. Histology-Safranin O/fast green and Alcian blue-of the retrieved specimens found more intense, uniform staining in the fibrin/HA composites. Analysis of the gene expression of the ECM molecules also confirmed the benefits of the composite with added HA in the maintenance of phenotypic stability. The present study suggests that fibrin/HA composite may serve as a dependable cell delivery vehicle as well as a structural basis for tissue-engineered cartilage. Key Words: Cartilage-Chondrocyte-Tissue engineering-Fibrin/hyaluronic acid composite-Fibrin.Biodegradable polymers have been one of the key components in cartilage tissue engineering. These polymers in the form of gel, sponge, and fiber serve as a scaffold in which chondrocytes are able to proliferate and differentiate. This technology allows cell/ polymer constructs to be implanted into cartilage defects and results in successful engraftment and new cartilage formation. General requirements of scaffolds are that they are 3D, highly porous with an interconnected pore network, biodegradable, and biocompatible. They should also carry appropriate surface properties for cell adhesion, proliferation, and differentiation. Proper mechanical properties are also required. Along with the synthetic scaffolds, many naturally derived scaffolds have been developed and examined in vitro and/or in vivo, including hyaluronate (HA) (1-3), fibrin (4-6), collagen (7), alginate (8,9), and chitosan (10). Although these materials have met those criteria in vitro, hyaline cartilage tissue formation is still challenging.It has been common practice that two or more biomaterials are combined to utilize the benefits of each biomaterial. Matrix engineering by adding various components has been successful to produce a composite matrix, such as fibrin-alginate (11), HAalg...

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This study represents the first epidemiological study based on the national registry of primary immunodeficiencies (PID) in Korea. Patient data were collected from 23 major hospitals. A total of 152 patients with PID (under 19 yr of age), who were observed from 2001 to 2005, have been entered in this registry. The period prevalence of PID in Korea in 2005 is 11.25 per million children. The following frequencies were found: antibody deficiencies, 53.3% (n = 81), phagocytic disorders, 28.9% (n = 44); combined immunodeficiencies, 13.2% (n = 20); and T cell deficiencies, 4.6% (n = 7). Congenital agammaglobulinemia (n = 21) and selective IgA deficiency (n = 21) were the most frequently reported antibody deficiency. Other reported deficiencies were common variable immunodeficiencies (n = 16), X-linked agammaglobulinemia (n = 15), IgG subclass deficiency (n = 4). Phagocytic disorder was mostly chronic granulomatous disease. A small number of patients with Wiskott-Aldrich syndrome, hyper-IgE syndrome, and severe combined immunodeficiency were also registered. Overall, the most common first manifestation was pneumonia. This study provides data that permit a more accurate estimation PID patients in Korea.