TY - JOUR TI - Future of Orthopaedic Sports Medicine and Soft Tissue Healing: The Important Role of Engineering AU - Woo, Savio L-Y. AU - Liang, Rui AU - Fisher, Matthew B. T2 - Cellular and Molecular Bioengineering DA - 2009/6/27/ PY - 2009/6/27/ DO - 10.1007/S12195-009-0065-7 VL - 2 IS - 3 SP - 448-461 J2 - Cel. Mol. Bioeng. LA - en OP - SN - 1865-5025 1865-5033 UR - http://dx.doi.org/10.1007/S12195-009-0065-7 DB - Crossref KW - Orthopaedics KW - Ligaments KW - Tendons KW - Functional tissue engineering KW - Biomechanics ER - TY - JOUR TI - Real time in vitro measurement of oxygen uptake rates for HEPG2 liver cells encapsulated in alginate matrices AU - Mishra, Anuja AU - Starly, Binil T2 - Microfluidics and Nanofluidics DA - 2009/1/23/ PY - 2009/1/23/ DO - 10.1007/s10404-008-0396-z VL - 6 IS - 3 SP - 373-381 J2 - Microfluid Nanofluid LA - en OP - SN - 1613-4982 1613-4990 UR - http://dx.doi.org/10.1007/s10404-008-0396-z DB - Crossref KW - Oxygen uptake rate (OUR) KW - Fiber optic sensor KW - Alginate KW - HEPG2 liver cells ER - TY - JOUR TI - Computer Aided Biomodeling and Analysis of Patient Specific Porous Titanium Mandibular Implants AU - Parthasarathy, Jayanthi AU - Starly, Binil AU - Raman, Shivakumar T2 - Journal of Medical Devices AB - Custom implants for the reconstruction of mandibular defects have recently gained importance due to their better performance over their generic counterparts. This is attributed to their precise adaptation to the region of implantation, reduced surgical times, and better cosmesis. Recent introduction of direct digital manufacturing technologies, which enable the fabrication of implants from patient specific data, has opened up a new horizon for the next generation of customized maxillofacial implants. In this article, we discuss a representative volume element based technique in which precisely defined porous implants with customized stiffness values are designed to match the stiffness and weight characteristics of surrounding healthy bone tissue. Dental abutment structures have been incorporated into the mandibular implant. Finite element analysis is used to assess the performance of the implant under masticatory loads. This design strategy lends itself very well to rapid manufacturing technologies based on metal sintering processes. DA - 2009/9/1/ PY - 2009/9/1/ DO - 10.1115/1.3192104 VL - 3 IS - 3 LA - en OP - SN - 1932-6181 1932-619X UR - http://dx.doi.org/10.1115/1.3192104 DB - Crossref KW - CT reconstruction mandibular implants KW - porous titanium layered manufacturing ER - TY - JOUR TI - A Lindenmayer system-based approach for the design of nutrient delivery networks in tissue constructs AU - Yasar, Ozlem AU - Lan, Shih-Feng AU - Starly, Binil T2 - Biofabrication AB - Large thick tissue constructs have reported limited success primarily due to the inability of cells to survive deep within the scaffold. Without access to adequate nutrients, cells placed deep within the tissue construct will die out, leading to non-uniform tissue regeneration. Currently, there is a necessity to design nutrient conduit networks within the tissue construct to enable cells to survive in the matrix. However, the design of complex networks within a tissue construct is challenging. In this paper, we present the Lindenmayer system, an elegant fractal-based language algorithm framework, to generate conduit networks in two- and three-dimensional architecture with several degrees of complexity. The conduit network maintains a parent–child relationship between each branch of the network. Several L-system parameters have been studied—branching angle, branch length, ratio of parent to child branch diameter, etc—to simulate several architectures under a given L-system notation. We have also presented a layered manufacturing-based UV-photopolymerization process using the Texas Instruments DLP™ system to fabricate the branched structures. This preliminary work showcases the applicability of L-system-based construct designs to drive scaffold fabrication systems. DA - 2009/12/1/ PY - 2009/12/1/ DO - 10.1088/1758-5082/1/4/045004 VL - 1 IS - 4 SP - 045004 J2 - Biofabrication OP - SN - 1758-5082 1758-5090 UR - http://dx.doi.org/10.1088/1758-5082/1/4/045004 DB - Crossref ER - TY - JOUR TI - Validation of the Cardiosphere Method to Culture Cardiac Progenitor Cells from Myocardial Tissue AU - Davis, Darryl R. AU - Zhang, Yiqiang AU - Smith, Rachel R. AU - Cheng, Ke AU - Terrovitis, John AU - Malliaras, Konstantinos AU - Li, Tao-Sheng AU - White, Anthony AU - Makkar, Raj AU - Marbán, Eduardo T2 - PLoS ONE AB - At least four laboratories have shown that endogenous cardiac progenitor cells (CPCs) can be grown directly from adult heart tissue in primary culture, as cardiospheres or their progeny (cardiosphere-derived cells, CDCs). Indeed, CDCs are already being tested in a clinical trial for cardiac regeneration. Nevertheless, the validity of the cardiosphere strategy to generate CPCs has been called into question by reports based on variant methods. In those reports, cardiospheres are argued to be cardiomyogenic only because of retained cardiomyocytes, and stem cell activity has been proposed to reflect hematological contamination. We use a variety of approaches (including genetic lineage tracing) to show that neither artifact is applicable to cardiospheres and CDCs grown using established methods, and we further document the stem cell characteristics (namely, clonogenicity and multilineage potential) of CDCs.CPCs were expanded from human endomyocardial biopsies (n = 160), adult bi-transgenic MerCreMer-Z/EG mice (n = 6), adult C57BL/6 mice (n = 18), adult GFP(+) C57BL/6 transgenic mice (n = 3), Yucatan mini pigs (n = 67), adult SCID beige mice (n = 8), and adult Wistar-Kyoto rats (n = 80). Cellular yield was enhanced by collagenase digestion and process standardization; yield was reduced in altered media and in specific animal strains. Heparinization/retrograde organ perfusion did not alter the ability to generate outgrowth from myocardial sample. The initial outgrowth from myocardial samples was enriched for sub-populations of CPCs (c-Kit(+)), endothelial cells (CD31(+), CD34(+)), and mesenchymal cells (CD90(+)). Lineage tracing using MerCreMer-Z/EG transgenic mice revealed that the presence of cardiomyocytes in the cellular outgrowth is not required for the generation of CPCs. Rat CDCs are shown to be clonogenic, and cloned CDCs exhibit spontaneous multineage potential.This study demonstrates that direct culture and expansion of CPCs from myocardial tissue is simple, straightforward, and reproducible when appropriate techniques are used. DA - 2009/9/25/ PY - 2009/9/25/ DO - 10.1371/journal.pone.0007195 VL - 4 IS - 9 SP - e7195 J2 - PLoS ONE LA - en OP - SN - 1932-6203 UR - http://dx.doi.org/10.1371/journal.pone.0007195 DB - Crossref ER - TY - JOUR TI - EVALUATION OF THE SERRATIA MARCESCENS NUCLEASE (NucA) AS A TRANSGENIC CELL ABLATION SYSTEM IN PORCINE AU - Caballero, I. AU - Piedrahita, J. A. T2 - ANIMAL BIOTECHNOLOGY AB - The efficiency of the Serratia marcescens nuclease encoded by the NucA gene, with or without a nuclear localization signal (NLS), and the commonly used diphtheria toxin A (DTA) were compared for their ability to ablate cells in culture. Constructs containing the test genes driven by the beta-actin promoter coupled with enhancer elements from the cytomegalovirus promoter and rabbit beta-globin gene (pCAG) and the blasticidin resistance gene driven by the phosphoglycerate kinase (PGK) promoter were generated and electroporated into porcine fetal fibroblasts. Three independent replicates were completed. Following blasticidin selection, the number of surviving colonies was counted to assess the efficiency of the toxic gene. Both NucA and DTA proved to be effective in killing porcine fibroblasts compared to controls. However, the efficiency of cell ablation was significantly higher with DTA than with NucA or NucANLS (p < 0.05). Gene expression analysis of surviving colonies indicated that survival is related to low or absent expression of the toxic genes. These results indicate that the NucA gene, while capable of mammalian cell ablation, is less efficient than DTA. DA - 2009/// PY - 2009/// DO - 10.1080/10495390903048235 VL - 20 IS - 4 SP - 177-185 SN - 1532-2378 KW - Ablation KW - DTA KW - Fibroblasts KW - NucA KW - Porcine ER - TY - JOUR TI - Characterization of Conserved and Nonconserved Imprinted Genes in Swine AU - Bischoff, Steve R. AU - Tsai, Shengdar AU - Hardison, Nicholas AU - Motsinger-Reif, Alison A. AU - Freking, Brad A. AU - Nonneman, Dan AU - Rohrer, Gary AU - Piedrahita, Jorge A. T2 - BIOLOGY OF REPRODUCTION AB - To increase our understanding of imprinted genes in swine, we carried out a comprehensive analysis of this gene family using two complementary approaches: expression and phenotypic profiling of parthenogenetic fetuses, and analysis of imprinting by pyrosequencing. The parthenote placenta and fetus were smaller than those of controls but had no obvious morphological differences at Day 28 of gestation. By Day 30, however, the parthenote placentas had decreased chorioallantoic folding, decreased chorionic ruggae, and reduction of fetal-maternal interface surface in comparison with stage-matched control fetuses. Using Affymetrix Porcine GeneChip microarrays and/or semiquantitative PCR, brain, fibroblast, liver, and placenta of Day 30 fetuses were profiled, and 25 imprinted genes were identified as differentially expressed in at least one of the four tissue types: AMPD3, CDKN1C, COPG2, DHCR7, DIRAS3, IGF2 (isoform specific), IGF2AS, IGF2R, MEG3, MEST, NAP1L5, NDN, NNAT, OSBPL1A, PEG3, APEG3, PEG10, PLAGL1, PON2, PPP1R9A, SGCE, SLC38A4, SNORD107, SNRPN, and TFPI2. For DIRAS3, PLAGL1, SGCE, and SLC38A4, tissue-specific differences were detected. In addition, we examined the imprinting status of candidate genes by quantitative allelic pyrosequencing. Samples were collected from Day 30 pregnancies generated from reciprocal crosses of Meishan and White Composite breeds, and single-nucleotide polymorphisms were identified in candidate genes. Imprinting was confirmed for DIRAS3, DLK1, H19, IGF2AS, NNAT, MEST, PEG10, PHLDA2, PLAGL1, SGCE, and SNORD107. We also found no evidence of imprinting in ASB4, ASCL2, CD81, COMMD1, DCN, DLX5, and H13. Combined, these results represent the most comprehensive survey of imprinted genes in swine to date. DA - 2009/11// PY - 2009/11// DO - 10.1095/biolreprod.109.078139 VL - 81 IS - 5 SP - 906-920 SN - 1529-7268 KW - assisted reproductive technology KW - comparative genomic imprinting KW - epigenetics KW - gene regulation KW - genomic imprinting KW - parthenogenesis KW - placenta KW - swine parthenote ER -