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Kim YS, Seo N, Kim JH, Kang S, Park JW, Park KD, Lee HA, Park M. Exploring the Functional Heterogeneity of Directly Reprogrammed Neural Stem Cell-Derived Neurons via Single-Cell RNA Sequencing. Cells 2023; 12:2818. [PMID: 38132138 PMCID: PMC10742074 DOI: 10.3390/cells12242818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/08/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
The therapeutic potential of directly reprogrammed neural stem cells (iNSCs) for neurodegenerative diseases relies on reducing the innate tumorigenicity of pluripotent stem cells. However, the heterogeneity within iNSCs is a major hurdle in quality control prior to clinical applications. Herein, we generated iNSCs from human fibroblasts, by transfecting transcription factors using Sendai virus particles, and characterized the expression of iNSC markers. Using immunostaining and quantitative real time -polymerase chain reaction (RT -qPCR), no differences were observed between colonies of iNSCs and iNSC-derived neurons. Unexpectedly, patch-clamp analysis of iNSC-derived neurons revealed distinctive action potential firing even within the same batch product. We performed single-cell RNA sequencing in fibroblasts, iNSCs, and iNSC-derived neurons to dissect their functional heterogeneity and identify cell fate regulators during direct reprogramming followed by neuronal differentiation. Pseudotime trajectory analysis revealed distinct cell types depending on their gene expression profiles. Differential gene expression analysis showed distinct NEUROG1, PEG3, and STMN2 expression patterns in iNSCs and iNSC-derived neurons. Taken together, we recommend performing a predictable functional assessment with appropriate surrogate markers to ensure the quality control of iNSCs and their differentiated neurons, particularly before cell banking for regenerative cell therapy.
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Affiliation(s)
- Yoo Sung Kim
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si 28159, Republic of Korea; (Y.S.K.); (N.S.); (J.-H.K.); (S.K.); (J.W.P.); (K.D.P.)
| | - NaRi Seo
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si 28159, Republic of Korea; (Y.S.K.); (N.S.); (J.-H.K.); (S.K.); (J.W.P.); (K.D.P.)
| | - Ji-Hye Kim
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si 28159, Republic of Korea; (Y.S.K.); (N.S.); (J.-H.K.); (S.K.); (J.W.P.); (K.D.P.)
| | - Soyeong Kang
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si 28159, Republic of Korea; (Y.S.K.); (N.S.); (J.-H.K.); (S.K.); (J.W.P.); (K.D.P.)
| | - Ji Won Park
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si 28159, Republic of Korea; (Y.S.K.); (N.S.); (J.-H.K.); (S.K.); (J.W.P.); (K.D.P.)
| | - Ki Dae Park
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si 28159, Republic of Korea; (Y.S.K.); (N.S.); (J.-H.K.); (S.K.); (J.W.P.); (K.D.P.)
| | - Hyang-Ae Lee
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon 34114, Republic of Korea;
| | - Misun Park
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju-si 28159, Republic of Korea; (Y.S.K.); (N.S.); (J.-H.K.); (S.K.); (J.W.P.); (K.D.P.)
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Kim YG, Yun JH, Park JW, Seong D, Lee SH, Park KD, Lee HA, Park M. Effect of Xenogeneic Substances on the Glycan Profiles and Electrophysiological Properties of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Int J Stem Cells 2023; 16:281-292. [PMID: 37105557 PMCID: PMC10465332 DOI: 10.15283/ijsc22158] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/30/2022] [Accepted: 02/12/2023] [Indexed: 04/29/2023] Open
Abstract
Background and Objectives Human induced pluripotent stem cell (hiPSC)-derived cardiomyocyte (CM) hold great promise as a cellular source of CM for cardiac function restoration in ischemic heart disease. However, the use of animal-derived xenogeneic substances during the biomanufacturing of hiPSC-CM can induce inadvertent immune responses or chronic inflammation, followed by tumorigenicity. In this study, we aimed to reveal the effects of xenogeneic substances on the functional properties and potential immunogenicity of hiPSC-CM during differentiation, demonstrating the quality and safety of hiPSC-based cell therapy. Methods and Results We successfully generated hiPSC-CM in the presence and absence of xenogeneic substances (xeno-containing (XC) and xeno-free (XF) conditions, respectively), and compared their characteristics, including the contractile functions and glycan profiles. Compared to XC-hiPSC-CM, XF-hiPSC-CM showed early onset of myocyte contractile beating and maturation, with a high expression of cardiac lineage-specific genes (ACTC1, TNNT2, and RYR2) by using MEA and RT-qPCR. We quantified N-glycolylneuraminic acid (Neu5Gc), a xenogeneic sialic acid, in hiPSC-CM using an indirect enzyme-linked immunosorbent assay and liquid chromatography-multiple reaction monitoring- mass spectrometry. Neu5Gc was incorporated into the glycans of hiPSC-CM during xeno-containing differentiation, whereas it was barely detected in XF-hiPSC-CM. Conclusions To the best of our knowledge, this is the first study to show that the electrophysiological function and glycan profiles of hiPSC-CM can be affected by the presence of xenogeneic substances during their differentiation and maturation. To ensure quality control and safety in hiPSC-based cell therapy, xenogeneic substances should be excluded from the biomanufacturing process.
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Affiliation(s)
- Yong Guk Kim
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea
| | - Jun Ho Yun
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea
| | - Ji Won Park
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea
| | - Dabin Seong
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea
| | - Su-hae Lee
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea
| | - Ki Dae Park
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea
| | - Hyang-Ae Lee
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Korea
| | - Misun Park
- Advanced Bioconvergence Product Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea
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Sohng C, Han MH, Park D, Park KD, Jang YH, Lee WJ, Lee SJ, Kim JY. Clinical features of subungual melanoma according to the extent of Hutchinson's nail sign: a retrospective single-centre study. J Eur Acad Dermatol Venereol 2020; 35:380-386. [PMID: 32562580 DOI: 10.1111/jdv.16762] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/27/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND Hutchinson's nail sign (HS) is among the diagnostic criteria for subungual melanoma (SUM). However, there is minimal evidence supporting the overall clinical significance of HS in SUM. OBJECTIVES To identify clinicopathological features of SUM according to the extent of HS. METHODS Retrospective cohort study was performed with consecutive SUM patients at a single centre from January 2006 to December 2017. The extent of HS was defined by the number of affected nail folds (range 0-4). Comparison groups were organized as follows: patients with HS (affecting ≥1 nail folds) vs. without HS; patients with HS affecting ≥2 nail folds vs. HS affecting <2 nail folds; patients with HS affecting ≥3 nail folds vs. HS affecting <3 nail folds. Clinicopathological characteristics of SUM were compared between the groups. RESULTS Sixty-one SUM patients were included. Forty-six (75.4%) exhibited HS; 22 (47.8%) on a toe and 24 (52.2%) on a finger. In multivariate analysis, nail destruction [hazard ratio (HR), 10.00; 95% confidence interval (CI), 2.61-38.30; P = 0.001] was significantly associated with the presence of HS and amputation was significantly associated with HS affecting ≥2 nail folds (HR, 4.75; 95% CI, 1.36-16.61; P = 0.015). High T stage (HR, 1.85; 95% CI, 1.20-2.85; P = 0.005, Fig. 2) was significantly associated with HS appearing in ≥3 nail folds. CONCLUSION Besides its value of detecting SUM, HS provides useful clinical information. The number of nail folds exhibiting HS could be a useful clinical clue for planning therapeutic strategies for SUM.
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Affiliation(s)
- C Sohng
- Department of Dermatology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea
| | - M H Han
- Department of Pathology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea
| | - D Park
- Department of Physical Medicine and Rehabilitation, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea
| | - K D Park
- Department of Dermatology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea
| | - Y H Jang
- Department of Dermatology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea
| | - W J Lee
- Department of Dermatology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea
| | - S J Lee
- Department of Dermatology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea
| | - J Y Kim
- Department of Dermatology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea
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Park HJ, Jang H, Kim JH, Lee JH, Shin HY, Kim SM, Park KD, Yim SV, Lee JH, Choi YC. Discovery of pathogenic variants in a large Korean cohort of inherited muscular disorders. Clin Genet 2016; 91:403-410. [PMID: 27363342 DOI: 10.1111/cge.12826] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 06/06/2016] [Accepted: 06/17/2016] [Indexed: 01/31/2023]
Abstract
Inherited muscular disorders (IMDs) are clinically and genetically heterogeneous genetic disorders. We investigated the mutational spectrum and genotype-phenotype correlations in Korean patients with IMD. We developed a targeted panel of 69 known IMD genes and recruited a total of 209 Korean patients with IMD. Targeted capture sequencing identified 994 different variants. Among them, 98 variants were classified as pathogenic/likely pathogenic variants; 38 were novel variations. A total of 39 patients had the pathogenic/likely pathogenic variants. Among them, 75 (36%) patients were genetically confirmed, and 18 (9%) patients had one heterozygous variant of recessive myopathy. However, two genetically confirmed patients had an additional heterozygous variant of another recessive myopathy. Four patients with one heterozygous variant of a recessive myopathy showed different phenotypes, compared with the known phenotype of the identified gene. The major causative genes of Korean patients with IMDs were DMD (19 patients), COL6A1 (9), DYSF (9), GNE (7), LMNA (7), CAPN3 (6), and RYR1 (5). This study showed the mutational and clinical spectra in Korean patients with IMD and confirmed the usefulness of strategies utilizing targeted sequencing.
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Affiliation(s)
- H J Park
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea.,Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - H Jang
- Department of Chemistry, Yonsei University, Seoul, Korea
| | - J H Kim
- Department of Clinical Pharmacology and Therapeutics, College of Medicine, Kyung Hee University, Seoul, Korea
| | - J H Lee
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - H Y Shin
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - S M Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - K D Park
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - S-V Yim
- Department of Clinical Pharmacology and Therapeutics, College of Medicine, Kyung Hee University, Seoul, Korea
| | - J H Lee
- Department of Clinical Pharmacology and Therapeutics, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Y-C Choi
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
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Kim SH, Bang SH, Kang SY, Park KD, Eom JH, Oh IU, Yoo SH, Kim CW, Baek SY. Human amniotic membrane-derived stromal cells (hAMSC) interact depending on breast cancer cell type through secreted molecules. Tissue Cell 2014; 47:10-6. [PMID: 25441616 DOI: 10.1016/j.tice.2014.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 09/06/2014] [Accepted: 10/10/2014] [Indexed: 12/26/2022]
Abstract
Human amniotic membrane-derived stromal cells (hAMSC) are candidates for cell-based therapies. We examined the characteristics of hAMSC including the interaction between hAMSC and breast cancer cells, MCF-7, and MDA-MB-231. Human amniotic membrane-derived stromal cells showed typical MSC properties, including fibroblast-like morphology, surface antigen expression, and mesodermal differentiation. To investigate cell-cell interaction via secreted molecules, we cultured breast cancer cells in hAMSC-conditioned medium (hAMSC-CM) and analyzed their proliferation, migration, and secretome profiles. MCF-7 and MDA-MB-231 cells exposed to hAMSC-CM showed increased proliferation and migration. However, in hAMSC-CM, MCF-7 cells proliferated significantly faster than MDA-MB-231 cells. When cultured in hAMSC-CM, MCF-7 cells migrated faster than MDA-MB-231 cells. Two cell types showed different profiles of secreted factors. MCF-7 cells expressed much amounts of IL-8, GRO, and MCP-1 in hAMSC-CM. Human amniotic membrane-derived stromal cells interact with breast cancer cells through secreted molecules. Factors secreted by hAMSCs promote the proliferation and migration of MCF-7 breast cancer cells. For much safe cell-based therapies using hAMSC, it is necessary to study carefully about interaction between hAMSC and cancer cells.
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Affiliation(s)
- Sun-Hee Kim
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea; Laboratory of Biopharmaceutical Process, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
| | - So Hee Bang
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea
| | - So Yeong Kang
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea
| | - Ki Dae Park
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea
| | - Jun Ho Eom
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea
| | - Il Ung Oh
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea
| | - Si Hyung Yoo
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea
| | - Chan-Wha Kim
- Laboratory of Biopharmaceutical Process, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea
| | - Sun Young Baek
- National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Chuncheongbuk-do 363-700, Republic of Korea
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An HS, Kim HY, Kim JB, Chang DS, Park KD, Lee JW, Myeong JI, An CM. Genetic characterization of hatchery populations of Korean spotted sea bass (Lateolabrax maculatus) using multiplex polymerase chain reaction assays. Genet Mol Res 2014; 13:6701-15. [PMID: 25177950 DOI: 10.4238/2014.august.28.14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The spotted sea bass, Lateolabrax maculatus, is an important commercial and recreational fishery resource in Korea. Aquacultural production of this species has increased because of recent resource declines, growing consumption, and ongoing government-operated stock release programs. Therefore, the genetic characterization of hatchery populations is necessary to maintain the genetic diversity of this species and to develop more effective aquaculture practices. In this study, the genetic diversity and structure of three cultured populations in Korea were assessed using multiplex assays with 12 highly polymorphic microsatellite loci; 144 alleles were identified. The number of alleles per locus ranged from 6 to 28, with an average of 13.1. The mean observed and expected heterozygosities were 0.724 and 0.753, respectively. Low levels of inbreeding were detected according to the inbreeding coefficient (mean FIS = 0.003-0.073). All hatchery populations were significantly differentiated from each other (overall fixation index (FST) = 0.027, P < 0.01), and no population formed a separate cluster. Pairwise multilocus FST tests, estimates of genetic distance, mantel test, and principal component analyses did not show a consistent relationship between geographic and genetic distances. These results could reflect the exchange of breeds and eggs between hatcheries and/or genetic drift due to intensive breeding practices. For optimal resource management, the genetic variation of hatchery stocks should be monitored and inbreeding controlled within the spotted sea bass stocks that are being released every year. This genetic information will be useful for the management of both L. maculatus fisheries and the aquaculture industry.
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Affiliation(s)
- H S An
- Biotechnology Research Division, National Fisheries Research and Development Institute, Busan, Korea
| | - H Y Kim
- Fisheries Resources and Environment Division, Southwest Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Yeosu, Korea
| | - J B Kim
- Fisheries Resources and Environment Division, Southwest Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Yeosu, Korea
| | - D S Chang
- Fisheries Resources and Environment Division, Southwest Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Yeosu, Korea
| | - K D Park
- Fishery Resource Research Institute, Gyongsangnamdo, Korea
| | - J W Lee
- Aquaculture Management Division, National Fisheries Research and Development Institute, Busan, Korea
| | - J I Myeong
- Aquaculture Management Division, National Fisheries Research and Development Institute, Busan, Korea
| | - C M An
- Biotechnology Research Division, National Fisheries Research and Development Institute, Busan, Korea
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Kang JS, Park KD, Ahn B, Han BS. Decreased Diethylnitrosamine-induced Liver Preneoplastic Lesions by Estradiol-3-benzoate Treatment. Toxicol Res 2013; 27:247-51. [PMID: 24278579 PMCID: PMC3834389 DOI: 10.5487/tr.2011.27.4.247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 10/12/2011] [Accepted: 10/21/2011] [Indexed: 11/22/2022] Open
Abstract
To clarify whether inhibitory effect of estrogen on liver tumor is associated with cell proliferation, we investigated its role in diethylnitrosamine (DEN)-induced rat preneoplastic lesions, with time sequenced manners. F344 male rats (n = 90) were divided into three groups at 5 weeks of age. The mini-osmotic pumps providing a continuous infusion of DEN was implanted into the abdominal cavity of each animal in group 1, 2 and 3 at 6 weeks of age. To see the effect of estrogen, pellet containing 1 or 10 μg of estradiol- 3-benzoate (EB) was implanted subcutaneously in the animals of groups 2 or 3, respectively, one week prior to DEN treatment. Ten animals of each group were euthanized at 10, 14 and 18 weeks after DEN treatment. Liver tissues at each time point were fixed in 10% phosphate-buffered formalin and were processed and embedded in paraffin and 5 μm sections mounted on a silanized slide. Glutathione S-transferase placental form (GST-P) positive foci and 5-bromo-2-deoxyuridine (BrdU) labeling cells were detected at each time point. Area of GST-P positive foci in DEN+EB 1 or 10 μg group was significantly decreased compared to DEN alone at 14 weeks (p < 0.01 or p < 0.05, respectively) an at 18 weeks (p < 0.05 or p < 0.01, respectively). BrdU index in DEN+EB 1 or 10 μg groups was significantly decreased compared to DEN alone at 14 weeks and at 18 weeks (p < 0.01). Taken together, we conclude that EB treatment decrease the DEN-induced liver preneoplastic lesions and this may be associated with decrease of cellular proliferation.
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Affiliation(s)
- Jin Seok Kang
- Department of Biomedical Laboratory Science, Namseoul University, Cheonan 330-707, Korea
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Kim SH, Bang SH, Park SA, Kang SY, Park KD, Oh IU, Yoo SH, Kim H, Kim CH, Baek SY. Character comparison of abdomen-derived and eyelid-derived mesenchymal stem cells. Cell Prolif 2013; 46:291-9. [PMID: 23692088 DOI: 10.1111/cpr.12027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 01/03/2013] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES While most human adipose tissues, such as those located in the abdomen, hip and thigh, are of mesodermal origin, adipose tissues located in the face are of ectodermal origin. The present study has compared stem cell-related features of abdomen-derived adult stem cells (A-ASCs) with those of eyelid-derived adult stem cells (E-ASCs). MATERIALS AND METHODS Adipose tissue-derived cells were maintained in DMEM supplemented with 10% FBS. Before passage 6, cells were analysed using FACS, immunocytochemistry and quantitative real time PCR (qRT-PCR). To examine multi-differentiational potential, early passage ASCs were cultivated in each of a commercial Stempro(®) Differentiation kit. RESULTS Unlike fibroblast-like morphology of A-ASCs, E-ASCs had bipolar morphology. Both types of cell exhibited similar surface antigens, and neuronal cell-related genes and proteins. However, there were differences in mRNA expression levels of CD90 and CD146; neuron-specific enolase (NSE) and nuclear receptor-related protein 1 (Nurr1) were different between the two cell types. There was no difference in multi-differentiational potential between 3 E-ASCs lines, however, E-ASCs had higher expression levels of chondrocyte-related genes compared to A-ASCs. These cells underwent senescence and maintained normal karyotypes. CONCLUSIONS Although isolated from similar adipose tissues, both types of cells displayed many contrasting characteristics. Understanding defining phenotypes of such cells is useful for making suitable choices in differing clinical indications.
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Affiliation(s)
- S-H Kim
- National Institute of Food and Drug Safety Evaluation, Korea Food and Drug Administration, Cheongwon-gun, Chuncheongbuk-do 363-700, South Korea
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Kang JW, Park KD, Choi Y, Baek DH, Cho WS, Choi M, Park JH, Choi KS, Kim HS, Yoo TM. Biodistribution and in vivo efficacy of genetically modified human mesenchymal stem cells systemically transplanted into a mouse bone fracture model. Arch Pharm Res 2013; 36:1013-22. [PMID: 23615814 DOI: 10.1007/s12272-013-0132-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 04/14/2013] [Indexed: 10/26/2022]
Abstract
Human mesenchymal stem cells (hMSCs) have generated a great deal of interest in clinical application due to their ability to undergo multi-lineage differentiation. Recently, ex vivo genetic modification of hMSCs was attempted to increase their differentiation potential. The present study was conducted to evaluate the biodistribution and in vivo efficacy of genetically modified hMSCs. To accomplish this, Runx2, which is a key transcription factor associated with osteoblast differentiation, was transduced into hMSCs using lentiviral vectors expressing green fluorescent protein (GFP) or luciferase. Here, we developed an experimental fracture in mice femur to investigate the effects of Runx2-transduced hMSCs on bone healing and migration into injury site. We conducted bio-luminescence imaging (BLI) using luciferase-tagged vector and quantitative real-time PCR using GFP probe to investigate the biodistribution of Runx2-transduced hMSCs in the fracture model. The biodistribution of hMSC cells in the fractured femur was observed at 14 days post-transplantation upon both BLI imaging and real-time PCR. Moreover, the fractured mice transplanted with Runx2-transduced hMSCs showed superior bone healing when compared to mock-transduced hMSC and MRC5 fibroblasts which were used as control. These data suggested that transplanted genetically modified hMSCs systemically migrate to the fractured femur, where they contribute to bone formation in vivo.
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Affiliation(s)
- Jin Wook Kang
- Biotechnological Development Assistance Team, National Institute of Food and Drug Safety Evaluation, Korea Food & Drug Administration, Osong Health Technology Administration Complex, 187 Osongsaengmyeong2(i)-ro, Osong-eup, Chengwon-gun, Chungcheongbuk-do 363-700, Republic of Korea.
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Choi BO, Park MH, Chung KW, Woo HM, Koo H, Chung HK, Choi KG, Park KD, Lee HJ, Hyun YS, Koo SK. Clinical and histopathological study of Charcot-Marie-Tooth neuropathy with a novel S90W mutation in BSCL2. Neurogenetics 2012; 14:35-42. [PMID: 23142943 DOI: 10.1007/s10048-012-0346-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/17/2012] [Indexed: 11/28/2022]
Abstract
The objective of the study was to investigate the disease-causing mutation in an autosomal dominant Charcot-Marie-Tooth disease type 2 family and examine the clinical and histopathological evaluation. We enrolled a family of Korean origin with axonal Charcot-Marie-Tooth disease neuropathy (FC305; 13 males, six females) and applied genome-wide linkage analysis. Whole exome sequencing was performed for two patients. In addition, sural nerve biopsies were obtained from two patients. Through whole exome sequencing, we identified an average of 20,336 coding variants from two patients. We also found evidence of linkage mapped to chromosome 11p11-11q13.3 (LOD score of 3.6). Among these variants in the linkage region, we detected a novel p.S90W mutation in the Berardinelli-Seip congenital lipodystrophy 2 (BSCL2) gene, after filtering 31 Korean control exomes. Our p.S90W patients had frequent sensory disturbances, pyramidal tract signs, and predominant right thenar muscle atrophy in comparison with reported p.S90L patients. The phenotypic spectra were wide and demonstrated intrafamilial variability. Two patients with different clinical features underwent sural nerve biopsies; the myelinated fiber densities were increased slightly in both patients, which differed from two previous case reports of BSCL2 mutations (p.S90L and p.N88S). This report expands the variability of the clinical spectrum associated with the BSCL2 gene and describes the first family with the p.S90W mutation.
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Affiliation(s)
- B-O Choi
- Department of Neurology, Ewha Womans University School of Medicine, Seoul, Korea
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Seo SH, Ahn HS, Yu YS, Kang HJ, Park KD, Cho SI, Park JS, Hyun YJ, Kim JY, Seong MW, Park SS. Mutation spectrum of RB1 gene in Korean bilateral retinoblastoma patients using direct sequencing and gene dosage analysis. Clin Genet 2012; 83:494-6. [PMID: 22963398 DOI: 10.1111/j.1399-0004.2012.01954.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/24/2012] [Accepted: 08/07/2012] [Indexed: 11/29/2022]
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Baek DH, Park SH, Park JH, Choi Y, Park KD, Kang JW, Choi KS, Kim HS. Embryotoxicity of lead (II) acetate and aroclor 1254 using a new end point of the embryonic stem cell test. Int J Toxicol 2012; 30:498-509. [PMID: 22013134 DOI: 10.1177/1091581811416522] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We developed a new end point of the mouse stem cell test (EST) for developmental neurotoxicity. We tested 2 developmental neurotoxicants, namely, lead (II) acetate and Aroclor 1254, using this EST. Our results showed that lead (II) acetate is nonembryotoxic, and Aroclor 1254 is weakly embryotoxic. To identify a new end point for developmental neurotoxicity, we used the default method of neuronal differentiation for D3 mouse embryonic stem cells with basic fibroblast growth factor (bFGF) and ascorbic acid. Flow cytometry and real-time polymerase chain reaction were used to quantify the inhibition of neuronal differentiation. Our results showed that both lead (II) acetate and Aroclor 1254 reduced the percentage of microtubule-associated protein 2 (MAP-2)-positive cells and the messenger RNA (mRNA) expression level of MAP-2 in a dose-dependent manner. These results suggested that these methods can be used to develop an additional end point of the EST for developmental neurotoxicity using default differentiation of mouse embryonic stem cells.
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Affiliation(s)
- Dae Hyun Baek
- National Institute of Food and Drug Safety Evaluation, Korea Food and Drug Administration, Cheongwon-gun, Chungcheongbuk-do, Korea
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Abstract
X-linked dominant Charcot-Marie-Tooth disease (CMTX) is an inherited peripheral neuropathy, caused mainly by a mutation of connexin 32 (Cx32) gene. We performed a mutation analysis of Cx32 by direct sequencing of the coding sequence, then identified 23 mutations from 28 Korean CMTX families. Nine mutations were not reported previously: Gly5Ser, Ser26fs, Val37Leu, Thr86Ile, Val152fs, Phe153Cys, Asp178X, Ala197Val, and Ile214Asn. The extracellular 2 (EC2) domain of Cx32 protein was the hot spot mutation domain in 44% of Koreans. Transmembrane domain 4 was rarely affected in Koreans (4%), compared with 14% of Europeans. The EC1 and intracellular domain was not affected in Koreans, although they were frequently affected in Europeans. This study revealed that the frequencies of CMTX with Cx32 mutations are specific to different ethnic groups. The frequency of CMTX (5.3%) caused by Cx32 mutation in Koreans is similar to those in Asians but lower than those in Europeans. This study suggests differences between CMTX patients with Cx32 mutations and ethnic background.
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Affiliation(s)
- Y Kim
- Department of Neurology, Ewha Womans University School of Medicine, Mok-dong, Yangchun-Gu, Seoul, South Korea
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Baek DH, An SY, Park JH, Choi Y, Park KD, Kang JW, Choi KS, Park SH, Whang MY, Han J, Kim JH, Kim HS, Geum D, Yoo TM. Transferability of a modified embryonic stem cell test using a new endpoint for developmental neurotoxicity. Toxicol Mech Methods 2011; 22:118-30. [PMID: 22082211 DOI: 10.3109/15376516.2011.603394] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We developed and analyzed a new surrogate endpoint of the mouse embryonic stem cell test (EST) for developmental neurotoxicity. To determine the sensitivity, specificity, and transferability of the new endpoint, a pre-validation team from three independent laboratories optimized and standardized the protocol for neuronal differentiation of mouse embryonic stem cells (mESCs) by measuring the neuronal differentiation rates of mESCs under different culture conditions, such as the presence or absence of basic fibroblast growth factor (bFGF) in the growth media and varying lengths of culture. In addition, a component ratio of neuronal cells was measured by using flow cytometry analysis of β-III tubulin (Tuj1)-positive cells and real-time polymerase chain reaction analysis of microtubule-associated protein 2 (MAP2) mRNA. Our results showed that the best growth was achieved by culturing mESCs for 12 d in N2B27 medium without bFGF or ascorbic acid. Lead (II) acetate and aroclor 1254 were used to test the usefulness of the new endpoint. When we used the known ID(50) values for lead (II) acetate in the EST model, it was classified as non-embryotoxic; however, when we used the new ID(50) values that we determined in this study, it was classified as weakly embryotoxic. Aroclor 1254 and penicillin G were also classified as weakly embryotoxic and non-embryotoxic compounds, respectively, when cardiac and neuronal differentiation ID(50) values were used. Therefore, our new surrogate endpoint for developmental neurotoxicity is not only sensitive and specific but also transferable among laboratories.
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Affiliation(s)
- Dae Hyun Baek
- National Institute of Food and Drug Safety Evaluation, Korea Food and Drug Administration , Cheongwon-gun, Chungcheongbuk-do Republic of Korea
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15
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An HS, Kim EM, Lee JH, Noh JK, An CM, Yoon SJ, Park KD, Myeong JI. Population genetic structure of wild and hatchery black rockfish Sebastes inermis in Korea, assessed using cross-species microsatellite markers. Genet Mol Res 2011; 10:2492-504. [PMID: 22009861 DOI: 10.4238/2011.october.13.6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The population structure of the black rockfish, Sebastes inermis (Sebastidae), was estimated using 10 microsatellite loci developed for S. schlegeli on samples of 174 individuals collected from three wild and three hatchery populations in Korea. Reduced genetic variation was detected in hatchery strains [overall number of alleles (N(A)) = 8.07; allelic richness (A(R)) = 7.37; observed heterozygosity (H(O)) = 0.641] compared with the wild samples (overall N(A) = 8.43; A(R) = 7.83; H(O) = 0.670), but the difference was not significant. Genetic differentiation among the populations was significant (overall F(ST) = 0.0237, P < 0.05). Pairwise F(ST) tests, neighbor-joining tree, and principal component analyses showed significant genetic heterogeneity among the hatchery strains and between wild and hatchery strains, but not among the wild populations, indicating high levels of gene flow along the southern coast of Korea, even though the black rockfish is a benthic, non-migratory marine species. Genetic differentiation among the hatchery strains could reflect genetic drift due to intensive breeding practices. Thus, in the interests of optimal resource management, genetic variation should be monitored and inbreeding controlled within stocks in commercial breeding programs. Information on genetic population structure based on cross-species microsatellite markers can aid in the proper management of S. inermis populations.
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Affiliation(s)
- H S An
- Genetics and Breeding Research Center, National Fisheries Research and Development Institute, Gyeongsangnamdo, Korea.
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16
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Park KD, Seong SK, Park YM, Choi Y, Park JH, Lee SH, Baek DH, Kang JW, Choi KS, Park SN, Kim DS, Kim SH, Kim HS. Telomerase reverse transcriptase related with telomerase activity regulates tumorigenic potential of mouse embryonic stem cells. Stem Cells Dev 2010; 20:149-57. [PMID: 20486780 DOI: 10.1089/scd.2009.0523] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Embryonic stem cell (ESC) research gave rise to the possibility that stem cell therapy could be used in the treatment of incurable diseases such as neurodegenerative disorders. However, problems related to the tumorigenicity of undifferentiated ESCs must be resolved before such cells can be used in the application of cell replacement therapies. In the present study, we attempted to determine biomarkers that predicted tumor formation of undifferentiated ESCs in vivo. We differentiated mouse ESCs (R1 cell line) into neural lineage using a 5-step method, and evaluated the expression of oncogenes (p53, Bax, c-myc, Bcl2, K-ras), telomerase-related genes (TERT, TRF), and telomerase activity and telomere length during differentiation of ESCs. The expression of oncogenes did not show a significant change during differentiation steps, but the expression of telomerase reverse transcriptase (TERT) and telomerase activity correlated with mouse ESCs differentiation. To investigate the possibility of mouse TERT (mTERT) as a biomarker of tumorigenicity of undifferentiated ESCs, we established mTERT knockdown ESCs using the shRNA lentivirus vector and evaluated its tumorigenicity in vivo using nude mice. Tumor volumes significantly decreased, and appearances of tumor formation in mice were delayed in the TERT-knockdown ESC treated group compared with the undifferentiated ESC treated group. Altogether, these results suggested that mTERT might be potentially beneficial as a biomarker, rather than oncogenes of somatic cells, for the assessment of ESCs tumorigenicity.
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Affiliation(s)
- Ki Dae Park
- Department of Pharmaceutical and Medical Device Research, National Institute of Food and Drug Safety Evaluation, Seoul, Korea
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Chung KW, Suh BC, Shy ME, Cho SY, Yoo JH, Park SW, Moon H, Park KD, Choi KG, Kim S, Kim SB, Shim DS, Kim SM, Sunwoo IN, Choi BO. Different clinical and magnetic resonance imaging features between Charcot-Marie-Tooth disease type 1A and 2A. Neuromuscul Disord 2008; 18:610-8. [PMID: 18602827 DOI: 10.1016/j.nmd.2008.05.012] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 05/23/2008] [Accepted: 05/28/2008] [Indexed: 01/01/2023]
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A) is the more frequent cause of demyelinating CMT, and CMT2A is the most common cause of axonal CMT. We conducted a magnetic resonance imaging (MRI) study on 39 CMT1A and 21 CMT2A patients to compare their neuroimaging patterns and correlate with clinical features. CMT1A patients showed selective fatty infiltration with a preference for anterior and lateral compartment muscles, whereas CMT2A patients showed a preference for superficial posterior compartment muscles. Early-onset CMT2A patients showed more severe leg fatty atrophy than late-onset CMT2A patients. In late-onset CMT2A, soleus muscle was the earliest, and most severely affected than the other leg muscles. Selective involvement of intrinsic foot muscles is a characteristic pattern of minimal CMT1A and CMT2A. Our MRI study demonstrates different patterns of fatty infiltration involving superficial posterior compartment muscles in CMT2A (partial T-type), and peroneal nerve innervated muscles in CMT1A (P-type).
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Affiliation(s)
- K W Chung
- Department of Biological Science, Kongju National University, Gongju, Republic of Korea
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18
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Kang JW, Choi Y, Park JH, Kim JS, Park KD, Baek DH, Seong SK, Choi KS, Lim SY, Kim HS. The effects of cyclin-dependent kinase inhibitors on adipogenic differentiation of human mesenchymal stem cells. Biochem Biophys Res Commun 2008; 366:624-30. [DOI: 10.1016/j.bbrc.2007.11.080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Accepted: 11/12/2007] [Indexed: 12/15/2022]
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19
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Muthukumarasamy R, Kang UG, Park KD, Jeon WT, Park CY, Cho YS, Kwon SW, Song J, Roh DH, Revathi G. Enumeration, isolation and identification of diazotrophs from Korean wetland rice varieties grown with long-term application of N and compost and their short-term inoculation effect on rice plants. J Appl Microbiol 2007; 102:981-91. [PMID: 17381741 DOI: 10.1111/j.1365-2672.2006.03157.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM This study has been aimed (i) to isolate and identify diazotrophs from Korean rice varieties; (ii) to examine the long-term effect of N and compost on the population dynamics of diazotrophs and (iii) to realize the shot-term inoculation effect of these diazotrophs on rice seedlings. METHODS AND RESULTS Diazotrophic and heterotrophic bacterial numbers were enumerated by most probable number method and the isolates were identified based on morphological, physiological, biochemical and 16s rDNA sequence analysis. Long-term application of fertilizer N with compost enhanced both these numbers in rice plants and its environment. Bacteria were high in numbers when malate and azelaic acids were used as carbon source, but less when sucrose was used as a carbon substrate. The combined application promoted the association of diazotrophic bacteria like Azospirillum spp., Herbaspirillum spp., Burkholderia spp., Gluconacetobacter diazotrophicus and Pseudomonas spp. in wetland rice plants. Detection of nifD genes from different diazotrophic isolates indicated their nitrogen fixing ability. Inoculation of a representative isolate from each group onto rice seedlings of the variety IR 36 grown in test tubes indicated the positive effect of these diazotrophs on the growth of rice seedlings though the percentage of N present in the plants did not differ much. CONCLUSIONS Application of compost with fertilizer N promoted the diazotrophic and heterotrophic bacterial numbers and their association with wetland rice and its environment. Compost application in high N fertilized fields would avert the reduction of N(2)-fixing bacterial numbers and their association was beneficial to the growth of rice plants. SIGNIFICANCE AND IMPACT OF THE STUDY The inhibitory effect of high N fertilization on diazotrophic bacterial numbers could be reduced by the application of compost and this observation would encourage more usage of organic manure. This study has also thrown light on the wider geographic distribution of G. diazotrophicus with wetland rice in temperate region where sugarcane (from which this bacterium was first reported to be associating and thereon from other plant species) is not cultivated.
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Affiliation(s)
- R Muthukumarasamy
- Main Bio-Control Research Laboratory, Goodwill Avenue, Venpakkam, Chengalpattu, India
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Chung KW, Kim SB, Park KD, Choi KG, Lee JH, Eun HW, Suh JS, Hwang JH, Kim WK, Seo BC, Kim SH, Son IH, Kim SM, Sunwoo IN, Choi BO. Early onset severe and late-onset mild Charcot-Marie-Tooth disease with mitofusin 2 (MFN2) mutations. Brain 2006; 129:2103-18. [PMID: 16835246 DOI: 10.1093/brain/awl174] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Mutations in the mitofusin 2 (MFN2) gene, which encodes a mitochondrial GTPase mitofusin protein, have recently been reported to cause both Charcot-Marie-Tooth 2A (CMT2A) and hereditary motor and sensory neuropathy VI (HMSN VI). It is well known that HMSN VI is an axonal CMT neuropathy with optic atrophy. However, the differences between CMT2A and HMSN VI with MFN2 mutations remained to be clarified. Therefore, we studied the phenotypic characteristics of CMT patients with MFN2 mutations. Mutations in MFN2 were screened in 62 unrelated axonal CMT neuropathy families. We calculated CMT neuropathy scores (CMTNSs) and functional disability scales (FDSs) to quantify disease severity. Twenty-one patients with the MFN2 mutations were studied by brain MRI. Ten pathogenic mutations were identified in 26 patients from 15 families (24.2%). Six of these mutations had not been reported, and de novo mutations were observed in five families (33.3%). The electrophysiological patterns of affected individuals with the MFN2 mutations were typical of axonal CMT; however, the clinical and electrophysiological characteristics were markedly different in early (<10 years) and late disease-onset (> or =10 years) groups. All patients with an early onset had severe CMTNS (> or =21) and FDS (6 or 7), whereas most patients with late onset had mild CMTNS (< or =10) and FDS (< or =3). We identified two HMSN VI families with the R364W mutation in the early onset group; however, two other families with the same mutation did not have optic atrophy. In addition, two early onset families with R94W mutations, previously reported for HMSN VI, did not have visual impairment. Interestingly, eight patients had periventricular and subcortical hyperintense lesions by brain MRI. In the late-onset group, three patients had sensorineural hearing loss and two had bilateral extensor plantar responses. We found that MFN2 mutations are the major cause of axonal CMT neuropathy, and that they are associated with variable CNS involvements. Phenotypes were significantly different in the early and late disease-onset groups. Our findings suggest that HMSN VI might be a variant of the early onset severe CMT2A phenotype.
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Affiliation(s)
- K W Chung
- Department of Neurology and Ewha Medical Research Center, Ewha Woman's University, College of Medicine, Dongdaemun Hospital, 70 Jongno 6-ga, Jongno-gu, 110-783, Seoul, Korea E-mail:
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Chung KW, Sunwoo IN, Kim SM, Park KD, Kim WK, Kim TS, Koo H, Cho M, Lee J, Choi BO. Two missense mutations of EGR2 R359W and GJB1 V136A in a Charcot-Marie-Tooth disease family. Neurogenetics 2005; 6:159-63. [PMID: 15947997 DOI: 10.1007/s10048-005-0217-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 03/09/2005] [Indexed: 01/28/2023]
Abstract
During mutational analysis of Charcot-Marie-Tooth (CMT) causative genes, we identified a CMT family with two missense mutations in different genes. A R359W mutation in EGR2 was shared by the affected daughter (proband) and her father. In addition, she had a V136A mutation in GJB1, which was determined to be a de novo mutation. The daughter with two different gene mutations showed more severe clinical, electrophysiological and histopathological phenotypes than her father who had only the EGR2 mutation. We suggest that these phenotypic differences between the proband and her father may have been caused by an altered effect of the genetic modifier in EGR2, or by the additive effect of the EGR2 and GJB1 mutations.
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Affiliation(s)
- K W Chung
- Department of Biological Science, Kongju National University, Kongju, South Korea
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Lee JW, Jung MC, Park HD, Park KD, Ryu GH. Synthesis and characterization of thermosensitive chitosan copolymer as a novel biomaterial. J Biomater Sci Polym Ed 2005; 15:1065-79. [PMID: 15461190 DOI: 10.1163/1568562041526496] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Novel water-soluble thermosensitive chitosan copolymers were prepared by graft polymerization of N-isopropylacrylamide (NIPAAm) onto chitosan using cerium ammonium nitrate (CAN) as an initiator. The physicochemical properties of the resulting chitosan-g-NIPAAm copolymers were characterized by Fourier transform infrared (FT-IR) spectroscopy, 1H-nuclear magnetic resonance, X-ray diffraction measurement, thermogravimetric analysis (TGA) and solubility test. Sol-gel transition behavior was investigated by the cloud point measurement of the chitosan-g-NIPAAm aqueous solution. The gelling temperature was examined using the vial inversion method. The percentage of grafting (%) and efficiency of grafting (%) were investigated according to concentrations of monomer and initiator. The maximum grafted chitosan copolymer was obtained with 0.4 M NIPAAm and 6 x 10(-3) M CAN. Water-soluble chitosan-g-NIPAAm copolymers were prepared successfully and they formed thermally reversible hydrogel, which exhibits a lower critical solution temperature (LCST) around 32 degrees C in aqueous solutions. A preliminary in vitro cell study showed nontoxic and biocompatible properties. These results suggest that chitosan-g-NIPAAm copolymer could be very useful in biomedical and pharmaceutical applications as an injectable material for cell and drug delivery.
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Affiliation(s)
- J W Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 442-749, South Korea
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Park KD, Kim J, Yang SJ, Yao A, Park JB. Preliminary study of interfacial shear strength between PMMA precoated UHMWPE acetabular cup and PMMA bone cement. J Biomed Mater Res B Appl Biomater 2003; 65:272-9. [PMID: 12687720 DOI: 10.1002/jbm.b.10006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Followed by successful demonstration of high interfacial tensile strength in a new design of cemented all-polyethylene acetabular cup, interfacial shear strength was investigated in this study, with the use of canine-size prototypes of polymethylmethacrylate (PMMA) precoated UHMWPE acetabular cups. In addition to the PMMA precoated prototypes, three different types of controls were also prepared and tested: grooved UHMWPE cups, PMMA (bone cement) cups, and noncoated, plain UHMWPE cups. The interfacial shear strength of the precoated prototypes was 10.1 +/- 0.69 MPa (n = 6), whereas it was 24.3 +/- 0.78 MPa (n = 2) for the PMMA cup, 6.95 +/- 0.21 MPa (n = 2) for the grooved UHMWPE cup, and 0.34 +/- 0.47 MPa (n = 2) for the UHMWPE cup. These results indicate benefits of the PMMA precoating to stabilize the polyethylene acetabular cup securely when applied with bone cement in simulated clinical applications. Analysis of the failed PMMA precoated UHMWPE prototype cups suggested that the chemically induced bonds between precoated PMMA layer and bone cement played a key role in developing high shear strength. After the interfacial shear test of the PMMA precoated prototypes, major disruptions at the interface between treated UHMWPE and precoated PMMA layer were observed by scanning electron microscopy (SEM), which was a unique failure pattern, not found with other prototypes.
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Affiliation(s)
- K D Park
- Department of Biomedical Engineering, 330 Engineering Technology Building, The University of Memphis, Memphis, Tennessee 38152, USA.
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Kwon IK, Park KD, Choi SW, Lee SH, Lee EB, Na JS, Kim SH, Kim YH. Fibroblast culture on surface-modified poly(glycolide-co-epsilon-caprolactone) scaffold for soft tissue regeneration. J Biomater Sci Polym Ed 2002; 12:1147-60. [PMID: 11853383 DOI: 10.1163/15685620152691904] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Novel porous matrices made of a copolymer of glycolide (G) and epsilon-caprolactone (CL) (51 : 49, Mw 103000) was prepared for tissue engineering using a solvent-casting particulate leaching method. Poly(glycolide-co-epsilon-caprolactone) (PGCL) copolymer showed a rubber-like elastic characteristic, in addition to an amorphous property and fast biodegradability. In order to investigate the effect on the fibroblast culture, PGCL scaffolds of varying porosity and pore size, in addition to surface-hydrolysis or collagen coating, were studied. The large pore-sized scaffold (pore size >150 microm) demonstrated a much greater cell adhesion and proliferation than the small pore-sized one. In addition, the higher porosity, the better the cell adhesion and proliferation. The surface-hydrolyzed PGCL scaffold showed enhanced cell adhesion and proliferation compared with the unmodified one. Type I collagen coating revealed a more pronounced contribution for increased cell interactions than the surface-hydrolyzed one. These results demonstrate that surface-modified PGCL scaffold can provide a suitable substrate for fibroblast culture, especially in the case of soft tissue regenerations.
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Affiliation(s)
- I K Kwon
- Biomaterials Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul
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Park KD, Khang GS, Lee HB, Park JB. Characterization of compression-molded UHMWPE, PMMA and PMMA/MMA treated UHMWPE: density measurement, FTIR-ATR, and DSC. Biomed Mater Eng 2002; 11:311-23. [PMID: 11790863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Considered one of the weak links in the total hip replacement (THR), efforts to enhance the interfacial strength between bone cement and ultra-high molecular weight polyethylene (UHMWPE) acetabular cup had been conducted in this laboratory. Following the successful demonstration of high interfacial strengths for our new acetabular component design, the nature of physical, chemical, and thermal property of the compression-molded specimens, including UHMWPE, PMMA/MMA treated UHMWPE, and PMMA has been investigated in this study. Density results from a density gradient column showed that the molding processes and conditions were adequate for complete sintering of UHMWPE and PMMA powders. FTIR-ATR results gave a direct evidence that PMMA did exist in the PMMA/MMA treated UHMWPE matrix. It also revealed a clear diffusion-related behavior across the interface. Under the high temperature and pressure, the UHMWPE powders undergo drastic changes of their morphology and crystalline structures. These changes were examined by differential scanning calorimeter (DSC) which showed a large difference in terms of % crystallinity. The percent of PMMA deposited in the treated UHMWPE was 17.8%, 18.8%, and 24.3% from the analyses of density, FTIR-ATR, and DSC, respectively. Finally, an evidence of diffusive behavior at the interface exhibited diffusion of PMMA occurring across the interfaces between the treated UHMWPE and UHMWPE or PMMA.
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Affiliation(s)
- K D Park
- Department of Biomedical Engineering, The University of Iowa, Iowa City, IA 52242, USA.
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Kong HS, Lee JH, Park KD, Ku SK, Lee HS. Immunohistochemical Study of the Endocrine Cells in the Pancreas of the Carp,Cyprinus carpio (Cyprinidae). J Vet Sci 2002. [DOI: 10.4142/jvs.2002.3.4.303] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hee Sun Kong
- Laboratory of Histology, College of Veterinary Medicine, Kyungpook National University, Taegu 702-701, Korea
| | - Jae Hyun Lee
- Laboratory of Histology, College of Veterinary Medicine, Kyungpook National University, Taegu 702-701, Korea
| | - Ki Dae Park
- Laboratory of Histology, College of Veterinary Medicine, Kyungpook National University, Taegu 702-701, Korea
| | - Sae Kwang Ku
- Laboratory of Histology, College of Veterinary Medicine, Kyungpook National University, Taegu 702-701, Korea
| | - Hyeung Sik Lee
- Laboratory of Histology, College of Veterinary Medicine, Kyungpook National University, Taegu 702-701, Korea
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Watanabe J, Ooya T, Park KD, Kim YH, Yui N. Preparation and characterization of poly(ethylene glycol) hydrogels cross-linked by hydrolyzable polyrotaxane. J Biomater Sci Polym Ed 2001; 11:1333-45. [PMID: 11261875 DOI: 10.1163/156856200744363] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PEG hydrogels cross-linked by a hydrolyzable polyrotaxane were prepared and their hydrolytic erosion characterized in terms of supramolecular dissociation of the polyrotaxane. The hydrolyzable polyrotaxane, in which many alpha-cyclodextrins (alpha-CDs) are threaded onto a poly(ethylene glycol) (PEG) chain capped with L-phenylalanine via ester linkages, was used as a multifunctional cross-linker: the PEG network was covalently bound to hydroxyl groups of alpha-CDs in the polyrotaxane. The contact angle and water content of the hydrogels were varied with the polyrotaxane content in the feed. In vitro hydrolysis study revealed that the time to reach complete gel erosion was shortened by increasing the polyrotaxane content in the feed in relation to the decreased number of chemical cross-links between PEG and alpha-CDs in the polyrotaxane. The hydrogel degradation in a physiological condition was found to be followed by bulk mechanism. These findings suggest that changing the preparative conditions such as polyrotaxane content will make it possible to control programmed gel erosion for tissue engineering.
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Affiliation(s)
- J Watanabe
- School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa
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Ko YG, Kim YH, Park KD, Lee HJ, Lee WK, Park HD, Kim SH, Lee GS, Ahn DJ. Immobilization of poly(ethylene glycol) or its sulfonate onto polymer surfaces by ozone oxidation. Biomaterials 2001; 22:2115-23. [PMID: 11432591 DOI: 10.1016/s0142-9612(00)00400-2] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel surface modification method has been developed to improve biocompatibility of polymeric biomaterials. This approach involves ozonation and then followed by graft polymerization with acrylates containing PEG, sulfonated PEG or by coupling of PEG derivatives. All the reactions were confirmed by ATR FT-IR and ESCA. The degree of ozonation measured by the iodide method was dependent on the ozone permeability of the polymers used. Surface hydrophilicity was investigated by measuring the contact angles. Ozonation itself yielded a slight increase in hydrophilicity and a decrease in platelet adhesion, but PEG immobilization showed a significant effect on surface hydrophilicity and platelet adhesion to confirm well-known PEG's passivity which minimize the adhesion of blood components on polymer surfaces. Both graft polymerization and coupling were effective for PU. In contrast, only grafting gave enough yields for PMMA and silicone. Platelet adhesion results demonstrated that all PEG modified surfaces adsorbed lower platelet adhesion than untreated or ozonated ones. Polymers coupled with sulfonated PEG exhibited the lowest platelet adhesion when compared with control and PEG coupled ones by virtue of the synergistic effect of non-adhesive PEG and negatively charged SO3 groups. This PEG or sulfonated PEG immobilization technology using ozonation is relatively simple for introducing uniform surface modification and therefore very useful for practical application of blood contacting medical devices.
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Affiliation(s)
- Y G Ko
- Biomaterials Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul, South Korea
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Lee JH, Ku SK, Park KD, Lee HS. Comparative study of endocrine cells in the principal pancreatic islets of two teleosts, Silurus asotus (Siluridae) and Siniperca scherzeri (Centropomidae). J Vet Sci 2001; 2:75-80. [PMID: 14614274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
The regional distribution and relative frequency of some endocrine cells in the principal pancreatic islets of two teleosts, Silurus asotus Linne (Siluridae) and Siniperca scherzeri Steindachner (Centropomidae), which have similar feeding habits, were observed using specific antisera against insulin, glucagon, somatostatin and bovine pancreatic polypeptide (bovine PP) using the peroxidase antiperoxidase (PAP) method. Spherical to spindle shaped cells were demonstrated in the principal pancreatic islets in both species of teleost fishes. However, they were not detected in the exocrine portions nor the pancreatic ducts. Insulin-immunoreactive cells were located in the central regions of the principal pancreatic islets at high frequency in both species. Glucagonimmunoreactive cells were restricted to the peripheral regions of the principal pancreatic islets in both species. They formed a mantle zone in the peripheral regions of Silurus asotus with moderate frequency, and occupied a narrower mantle zone in Siniperca scherzeri with moderate frequency. In addition, glucagonimmunoreactive cell cores were also found in the peripheral zone of some principal pancreatic islets of Siniperca scherzeri. Somatostatin-immunoreactive cells were dispersed in the central zone of the principal pancreatic islets of Silurus asotus with moderate frequency, but were located in the peripheral regions with low frequency in Siniperca scherzeri. Bovine PPimmunoreactive cells were found in the peripheral region and the mantle zone of the principal pancreatic islets with low and rare frequency, respectively in both species. In conclusion, the regional distribution and relative frequency of endocrine cells in the principal pancreatic islets of Silurus asotus showed general patterns similar to those of other teleostean fishes. But, some speciesdependent distributional patterns and/or relative frequencies, particularly in glucagon-, somatostatin- and bovine PP-immunoreactive cells, were detected in the principal pancreatic islets of Siniperca scherzeri.
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Affiliation(s)
- J H Lee
- Laboratory of Histology, College of Veterinary Medicine, Kyungpook National University, Taegu 702-701, Korea.
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31
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Lee WK, Park KD, Kim YH, Suh H, Park JC, Lee JE, Sun K, Baek MJ, Kim HM, Kim SH. Improved calcification resistance and biocompatibility of tissue patch grafted with sulfonated PEO or heparin after glutaraldehyde fixation. J Biomed Mater Res 2001; 58:27-35. [PMID: 11152994 DOI: 10.1002/1097-4636(2001)58:1<27::aid-jbm40>3.0.co;2-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A novel chemical modification of biological tissues was developed aimed at improving biocompatibility and calcification resistance. This method involved the additional grafting of sulfonated PEO (PEO-SO(3)) or heparin after conventional glutaraldehyde (GA) fixation of bovine pericardium (BP). The amino groups of PEO-SO(3) or heparin were utilized to react to the GA residues to block them. The PEO-SO(3) or heparin grafted tissues demonstrated a slightly higher shrinkage temperature and tensile strength, but greater resistance to collagenase digestion, than GA treated ones. These results suggest that modified tissues have improved durability due to the grafting and filling effect of PEO-SO(3) or heparin in addition to the GA cross-linking. At the direct contact cytotoxicity test in vitro, PEO-SO(3) or heparin grafted tissue was shown to be nontoxic, while relatively significant cytotoxicity was observed for the GA treated tissues, possibly due to the release of GA. From the in vivo calcification study, calcium contents deposited on the modified tissues were much less than those on GA treated tissues. Such a decreased calcification might be explained by the decrease of residual GA groups during the additional treatment, and the space-filling effect and the nonadhesive property and/or the blood compatibility of PEO-SO(3) or heparin grafted covalently. The newly modified tissue patch was observed to show improved pathological assessibility including less inflammation and tissue reactions. This simple modification method may be useful for calcification-resistant and blood-compatible tissue patches for cardiovascular implants.
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Affiliation(s)
- W K Lee
- Korea Institute of Science and Technology, Biomaterials Research Center, P.O. Box 131, Cheongnyang, Seoul 130-650, Korea
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32
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Abstract
To investigate the effects of basement membrane proteins on the reconstruction of mucosa equivalent, oral mucosa substitute were cultured on (1) type I collagen gels, (2) type IV collagen-coated type I collagen gels, (3) laminin-coated type I collagen gels, and (4) type I collagen gels containing both type IV collagen and laminin. H/E and PAS staining showed that the characteristics of the oral mucosa were preserved under all the experimental conditions. However, the basal keratinocytes appeared cuboidal when the type I collagen gels were coated with type IV collagen plus laminin. The expression of the differentiation markers was similar, but weak staining of filaggrin, K13, and involucrin was observed with the type IV collagen plus laminin coating. Furthermore, electron microscopy revealed that the size of the basal keratinocytes was relatively small and uniform when both type IV collagen and laminin were used. These findings suggested that these two major basement membrane proteins are important in the process of differentiation in mucosal keratinocytes.
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Affiliation(s)
- S W Kim
- Department of Plastic and Reconstructive Surgery, Seoul National University, College of Medicine, Seoul, Korea
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Kim MK, Park IS, Park HD, Wee WR, Lee JH, Park KD, Kim SH, Kim YH. Effect of poly(ethylene glycol) graft polymerization of poly(methyl methacrylate) on cell adhesion. J Cataract Refract Surg 2001; 27:766-74. [PMID: 11377910 DOI: 10.1016/s0886-3350(00)00701-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To investigate the effect of surface modification of poly(methyl methacrylate) (PMMA) by poly(ethylene glycol) (PEG) grafting on cell adhesion. SETTING Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea. METHODS The PMMA surface was oxidized with ozone, and PEG acrylate was then graft polymerized. To verify the PEG grafting on the surface, the oxygen content was measured by electron spectroscopy for chemical analysis. The contact angle was measured using the Wilhelmy plate method. The adhesion of keratocytes on modified PMMA was investigated in vitro. Cultured rabbit keratocytes (4 x10(5) cells/mL) were layered on each PMMA disk, cultured in a carbon dioxide incubator for 24 hours, harvested by trypsinization, and counted. A commercially available intraocular lens was modified as described and then inserted in the anterior chamber of a white rabbit. The cell adherence pattern on the modified IOL was examined by scanning electron microscopy. RESULTS The PEG-grafted PMMA revealed a higher oxygen content and lower dynamic receding contact angles than the untreated PMMA. The mean number of adhered cells was 72.5 +/- 22 x 10(4)/mL for untreated PMMA. After PEG grafting of 1 hour and ozone oxidation of 2 hours, the adherent cell counts significantly decreased to 6.5 +/- 1.7 x 10(4)/mL and 7.6 +/- 1.6 x 10(4)/mL, respectively (P =.002). Scanning electron microscopy showed small round cells sparsely scattered on the modified PMMA in contrast to the untreated PMMA. CONCLUSION Surface modification of PMMA using PEG grafting reduced cell adhesion. This may decrease the incidence of retroprosthetic membrane formation after keratoprosthesis surgery.
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Affiliation(s)
- M K Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
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34
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Ku SK, Lee HS, Park KD, Lee JH. An immunohistochemical study on the pancreatic islets cells of the Mongolian gerbils, Meriones unguiculatus. J Vet Sci 2001; 2:9-14. [PMID: 14614288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
In order to study the regional distribution and relative frequency of the immunoreactive endocrine cells in the pancreatic islets of the Mongolian gerbil, pancreatic sections of Meriones unguiculatus were immunostained using an immunohistochemical (PAP) method with four types of specific antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). The pancreatic islets were subdivided into three portions (central region, mantle zone and peripheral region) according to their composition of immunoreactive cells. Spherical to spindle shaped insulin, glucagon, somatostatin and PP-immunoreactive cells were observed in this study. Insulin-immunoreactive cells were present in the central regions with high frequency, and a few of these cells were also demonstrated in the mantle zones. Glucagon-immunoreactive cells were mainly restricted to the mantle zones. However, rare examples were found in the peripheral regions. As for the glucagon-immunoreactive cells, somatostatin-immunoreactive cells were detected in the mantle zones and peripheral regions with moderate and rare frequencies, respectively. PP-immunoreactive cells were found in the mantle zones and peripheral regions with rare and moderate frequencies, respectively. In the mantle and the peripheral regions, cytoplasmic process of glucagon-, somatostatin- and PP-immunoreactive cells were intermingled. In conclusion, the regional distribution of endocrine cells in the pancreatic islets of Mongolian gerbil was found to be similar to that of other mammals, especially other rodents, except for the topographical different distribution of somatostatin which differs that of other rodents.
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Affiliation(s)
- S K Ku
- Pharmacology & Toxicology Lab., Central Research Laboratories, Dong-Wha Pharm. Ind. Co., Anyang 430-017, Korea
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35
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Park KD, Park JB. Interfacial strength of compression-molded specimens between PMMA powder and PMMA/MMA monomer solution-treated ultra-high molecular weight polyethylene (UHMWPE) powder. J Biomed Mater Res 2001; 53:737-47. [PMID: 11074434 DOI: 10.1002/1097-4636(2000)53:6<737::aid-jbm17>3.0.co;2-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The interface between bone cement and ultra-high molecular weight polyethylene (UHMWPE) has been considered a weak link of cemented UHMWPE acetabular cup in total hip replacement (THR). For the improvement of this weak interface, adhesion between the UHMWPE acetabular cup and bone cement made of polymethylmethacrylate (PMMA) has been investigated in our laboratory. Virgin UHMWPE powders were treated with methyl methacrylate (MMA) monomer and PMMA/MMA solution. The treated UHMWPE powders were then compression-molded with virgin UHMWPE powders or PMMA powders, creating two different interfaces, i. e., treated/virgin UHMWPE powder and treated UHMWPE/PMMA powder. For the present study, the interfacial strengths between PMMA powder and the treated UHMWPE power were investigated following the same protocol previously set. The maximum interfacial strength was 17.0 +/- 0.25MPa with the same molding condition of 166.5 degrees C, 38.7 MPa and l h. In addition to the molding condition, we tested the strengths for the treated UHMWPE powders, which have different ratios between PMMA/MMA solution and MMA-treated UHMWPE powders. Significant differences on the interfacial strengths resulted due to the ratio change; more PMMA in the PMMA/MMA solution-treated UHMWPE powder exhibited higher interfacial strength. Scanning electron microscopic (SEM) pictures showed that the interface is composed of three major portions: PMMA powder, UHMWPE, and coated PMMA, indicating strong mechanical interlocking of UHMWPE and PMMA powder matrix and chemical bonding between PMMA powder and the precoated PMMA onto the UHMWPE. In addition, another interfacial strength between PMMA powder, which is equivalent to the outermost part of the cup, and bone cement was investigated. The average strength reached up to 42.4 +/- 3.6 MPa, close to the tensile strength of bone cement itself.
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Affiliation(s)
- K D Park
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242-1527, USA
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36
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Ku SK, Lee HS, Lee JH, Park KD. An immunohistochemical study on the endocrine cells in the alimentary tract of the red-eared slider (Trachemys scripta elegans). Anat Histol Embryol 2001; 30:33-9. [PMID: 11284161 DOI: 10.1046/j.1439-0264.2001.00284.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The regional distribution and relative frequency of endocrine cells in the alimentary tract of the red-eared slider, Trachemys scripta elegans, were investigated by immunohistochemical methods using 10 antisera. Most of the immunoreactive cells in the intestine were spherical or spindle-like in shape (open-type cells), while round cells (closed-type cells) were occasionally found in the stomach. These immunoreactive cells were located in the basal portion of the intestine, including the oesophagus, and in the gastric glands of the stomach. Cg A-immunoreactive cells were restricted to the pylorus and duodenum and were few in number. Serotonin-immunoreactive cells, which were most commonly found in the pylorus, were found in the epithelia throughout the alimentary tract at various frequencies. Gastrin-immunoreactive cells were found in the pylorus, duodenum and jejunum at moderate, low and very low frequencies, respectively. Somatostatin-immunoreactive cells were found throughout the alimentary tract except for the rectum, at various frequencies. Glucagon-immunoreactive cells were detected in the fundus, pylorus, jejunum and ileum at low or very low frequencies. CCK-8-immunoreactive cells were found in the pylorus, fundus and duodenum at very low, low and moderate frequencies, respectively. Bombesin-immunoreactive cells were restricted to the fundus and pylorus at low frequencies. No secretin-, BPP- or VIP-immunoreactive cells were found in this study.
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Affiliation(s)
- S K Ku
- Department of Biology, Faculty of Basic Science, Kyungsan University, Kyungsan, Republic of Korea
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37
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Lee JH, Ku SK, Park KD, Lee HS. Comparative study of endocrine cells in the principal pancreatic islets of two teleosts, Silurus asotus (Siluridae) and Siniperca scherzeri (Centropomidae). J Vet Sci 2001. [DOI: 10.4142/jvs.2001.2.2.75] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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38
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Ku SK, Lee HS, Park KD, Lee JH. An immunohistochemical study on the pancreatic islets cells of the Mongolian gerbils, Meriones unguiculatus. J Vet Sci 2001. [DOI: 10.4142/jvs.2001.2.1.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Park JC, Hwang YS, Lee JE, Park KD, Matsumura K, Hyon SH, Suh H. Type I atelocollagen grafting onto ozone-treated polyurethane films: cell attachment, proliferation, and collagen synthesis. J Biomed Mater Res 2000; 52:669-77. [PMID: 11033549 DOI: 10.1002/1097-4636(20001215)52:4<669::aid-jbm11>3.0.co;2-u] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
An approach is presented for the graft copolymerization of type I atelocollagen onto the surface of polyurethane (PU) films treated with ozone. Through inducing oxidization to modify PU surface by ozone, peroxide groups are easily generated on the surface. Those peroxides are broken by redox-polymerization, and provide active species which initiate graft polymerization by reacting with amines in the collagen molecules. The ozone oxidation time and voltage could readily control the amount of peroxide production. The surface density of generated peroxides on PU surface was determined by iodide method. The maximum concentration of peroxide was about 10.20 x 10(-8)mol/cm(2) when ozone oxidation was performed at 60 V for 30 min. After the reaction of PU by ozone oxidation, type I atelocollagen was graft-copolymerized onto the PU film. All the physical measurements on the collagen-grafted surface indicated that the PU surface was effectively covered with type I atelocollagen. The interaction of the collagen-grafted PU surface with fibroblasts could be greatly enhanced by the surface graft polymerization with type I atelocollagen. Attachment and proliferation of fibroblasts on the grafted type I atelocollagen were significantly enhanced, and it is assumed that the atelocollagen matrix supported the initial attachment and growth of cells. In the early stage of proliferation, collagen synthesis in fibroblasts was not activated and remained at a relatively low level due to the grafted type I atelocollagen, increasing only with fibroblast differentiation.
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Affiliation(s)
- J C Park
- Department of Medical Engineering, Yonsei University College of Medicine, 134, Shinchon-dong, Seodaemun-ku, Seoul 120-752, Korea
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Abstract
Tissue engineering can serve as an alternative treatment for a malfunctioning or lost organ. Isolated and expanded cells adhere to a temporary scaffold, proliferate, and secrete their own extracellular matrices (ECM) replacing the biodegrading scaffold. The genitourinary system, composed of the kidney, ureter, bladder, urethra, and genital organs, is exposed to a variety of possible injury sites from the time of fetal development. All the urinary organs are mainly composed of smooth muscle and uroepithelial cells and which may be approached by tissue engineering techniques. A large number of materials, including naturally-derived and synthetic polymers have been utilized to fabricate prostheses for the genitourinary system. Usually, whenever there is a lack of native urologic tissue, reconstruction is considered with native non-urologic tissue, such as, gastrointestinal segments, or skin or mucosa from multiple body sites. Engineering tissues using selective cell transplantation may provide a means to create functional new genitourinary tissues. This review concerns urinary tissues reconstructed with bladder uroepithelial cells and smooth muscle cells (SMCs) implanted on biodegradable polymer matrices.
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Affiliation(s)
- K D Park
- Department of Molecular Science and Technology, Ajou University, Suwon, Korea.
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41
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Abstract
A novel chemical modification of biological tissues was developed by the direct coupling heparin to bovine pericardium (BP). The heparinization involves pretreatment of BP using GA and followed by grafting heparin to BP by the reaction of residual aldehyde and amine group of heparin. BP was modified by direct coupling of heparin and the effect of heparin coupling on calcification was evaluated in vitro and in vivo. Heparinized BP was characterized by measuring shrinkage temperature, mechanical properties, digestion resistance to collagenase enzyme, in vitro cytotoxicity, and in vivo calcification. Thermal and mechanical properties showed that the durability of heparin-treated tissue increased as compared with fresh tissue and GA-treated tissue. Resistance to collagenase digestion revealed that heparin-treated tissue has greater resistance to enzyme digestion than did fresh tissue and GA-treated tissue. Heparinized tissue had shown to be non-cytotoxic, however, relatively high cytotoxicity was observed in the GA-treated tissues due to the release of GA. In vivo calcification study demonstrated much less calcium deposition on heparin-treated BP than GA-treated one. Obtained results attest to the usefulness of heparinized BP for cardiovascular bioprostheses.
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Affiliation(s)
- W K Lee
- Biomaterials Research Center, Korea Institute Science and Technology, Seoul , South Korea
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Park KD, Kang YH, Park JB. Interfacial strength between molded UHMWPE and PMMA-MMA monomer treated UHMWPE. J Long Term Eff Med Implants 2000; 9:303-18. [PMID: 10847970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
To solve aseptic loosening of cemented acetabular cup and tibial plateaus of hips and knee joint prostheses in total joint replacement, adhesion between the polymeric prostheses made of ultra-high molecular weight polyethylene (UHMWPE) and bone cement made of polymethyl-methacrylate (PMMA) has been investigated. Previous studies using xylene, PMMA, and MMA monomer solution to treat bulk surfaces of UHMWPE resulted in 11.5 +/- 0.65 MPa as the maximum interfacial strength between the treated UHMWPE and bone cement. The present study eliminates the use of xylene; instead, UHMWPE powders were treated with MMA monomer and PMMA-MMA solution, dried, and then compression-molded with untreated UHMWPE powders. The interfacial tensile strengths were measured and the best molding conditions investigated by varying temperature, pressure, and time. Temperature was the predominant factor when compared to that of pressure or time. The maximum interfacial strength between the treated UHMWPE and untreated UHMWPE was 16.3 +/- 0.94 MPa with the molding conditions of 166.5 degrees C, 38.7 MPa, and 1 h. Scanning electron microscopic (SEM) pictures show the coating of the nodules and fibrils of UHMWPE powder with PMMA. Pulled out aggregated nodular space and coated PMMA after fracture could be seen easily from PMMA-MMA treated UHMWPE powder.
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Affiliation(s)
- K D Park
- Department of Biomedical Engineering, University of Iowa, Iowa City 52242-1527, USA
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Moon JS, Sunwoo IN, Kim SM, Lee SA, Cho KH, Park KD, Kim WK, Choi BO, Chun HY. Clinical analysis of 12 Korean Lambert-Eaton myasthenic syndrome (LEMS) patients. Yonsei Med J 1999; 40:454-9. [PMID: 10565256 DOI: 10.3349/ymj.1999.40.5.454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The Lambert-Eaton myasthenic syndrome (LEMS) heralds the occurrence of malignancy, especially small-cell lung cancer (SCLC), but it can also occur in the absence of cancer. Twelve patients were diagnosed as LEMS by clinical features and the classical electrophysiological triad, which includes a low amplitude of compound muscle action potentials (CMAP), decremental responses on low-rate stimulation, and incremental responses on high-rate stimulation on the repetitive nerve stimulation (RNS) test. There were 6 male and 6 female patients, ranging in age from 49 to 66 years. Malignancy(all were SCLC) was found in 7 patients. Males predominantly expressed the paraneoplastic form; whereas the primary autoimmune form was found only in women, who showed a good response to corticosteroid treatment. The neurological features were similar in both groups: proximal lower limb weakness, depressed muscle stretch reflexes, and dryness of mouth in nearly all patients. Bulbar dysfunction and limb paresthesia were a little more frequent in the paraneoplastic form. In RNS tests, the characteristic electrophysiological abnormalities were found in all patients and were more profound in the paraneoplastic form. We concluded that LEMS is commonly associated with malignancy, especially SCLC, but it should also be stressed that there are many female LEMS patients who do not harbor any malignancy at all, and that other treatment strategies such as immunotherapy should be considered for these patients.
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Affiliation(s)
- J S Moon
- Department of Neurology, Yonsei University Wonju College of Medicine, Seoul, Korea
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Lee HW, Koo H, Choi KG, Park KD, Lee BC. The effects of peripheral leukocytes on the hippocampal neuronal changes in transient global ischemia and unilateral cerebral hemispheric infarction. J Korean Med Sci 1999; 14:304-14. [PMID: 10402174 PMCID: PMC3054372 DOI: 10.3346/jkms.1999.14.3.304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The participation of activated leukocytes and subsequent production of chemical mediators has been well accepted in the pathophysiology of hypoxic-ischemic injury. This study was performed to see the effects of leukocytes on hippocampal neuronal damage in transient global ischemia induced by 10-min occlusion of bilateral common carotid arteries (CCAs) with reperfusion for various times, and in complete unilateral ischemia induced by 24-hr ligation of left CCA. Leukopenia was induced by intraperitoneal injection of cyclophosphamide for 4 days. The results showed that hippocampal neuronal damages were worse at 6-hr reperfusion in leukopenic experimental group than in the control group. In comparison, 24-hr and 3-day reperfusion leukopenic groups showed less numbers of damaged neurons and milder changes. The 5-day reperfusion group showed inconsistent changes. Unilateral CCA occlusion showed extensive infarction in 83.3% of gerbils in the control group, compared to 25% of gerbils in the experimental group (p<0.05). These results strongly suggest that the number of peripheral leukocytes were closely related to the development of delayed neuronal damage of hippocampus in transient global ischemia and the incidence of infarction induced by 24-hr unilateral CCA ligation.
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Affiliation(s)
- H W Lee
- Department of Neurology, Ewha Womans University College of Medicine, Seoul, Korea.
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Abstract
Wilson disease (WD), an autosomal recessive disorder of copper transport, is marked by impaired biliary excretion and incorporation of copper into ceruloplasmin. Molecular mechanism regulating the expression of the WD gene was studied. We isolated, sequenced, and characterized approximately 1.3 kb of the 5'-flanking region of the WD gene from the human genomic library. The approximately 1.3 kb of the WD sequence directed high level of luciferase activity in HepG2 cells. Interestingly, the 5'-flanking region contained four metal response elements (MREs) and six MRE-like sequences (MLSs), usually found in the metallothionein genes. It also contained a number of putative regulatory elements such as Sp1, AP-1, AP-2, and E-box, but lacked TATA box. The transcription start site was located at 335 base pairs upstream of the translation initiation site. Successive 5'-deletion analyses suggested that the 159-base pair region from -811 to -653, which includes MLS2 (-802 to -796) and MLS3 (-785 to -779), contained one or more positive regulatory element(s). A negative element was also identified at region -1038 to -812. A protein-MLS complex was identified through electrophoretic mobility shift and competition assay using MLS2/MLS3 and HepG2 cell nuclear proteins.
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Affiliation(s)
- W J Oh
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Taejon, 305-701, Korea
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46
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Abstract
Polyurethane (PU), based on poly(dimethyl siloxane) (PDMS) as a soft segment, with monomethoxy poly(ethylene glycol) (MPEG) grafted onto it, was synthesized as a new polymeric biomaterial for coating PDMS-based biomedical devices. Two different chain extenders, ethylene glycol (EG) and diethyl bis(hydroxymethyl) malonate (DBM), were used for the synthesis of PDMS-based PUs and then MPEG was grafted onto them by allophanate and esterification reactions, respectively. Their molecular structures were confirmed qualitatively and quantitatively using FT-IR and 1H-NMR measurements. PDMS-based PU was more hydrophobic than Pellethane, which is a commercial biomedical-grade poly(ether urethane), due to the PDMS-rich phase at the polymeric surface. However, the incorporation of MPEG in PDMS-based PU induced an increase in hydrophilicity. Analyses of their morphology using dynamic mechanical analysis and differential scanning calorimetry showed that the degree of phase separation increased with the content of hard segments. It also showed that MPEG is compatible with a hard segment consisting of 4,4'-diphenylmethane diisocyanate (MDI) and DBM, while being incompatible with one consisting of MDI and EG. Platelet adhesions with PDMS-based PUs were significantly reduced when compared with Pellethane. It was also observed from a platelet adhesion experiment that the incorportion of MPEG further reduced platelet adhesion. PDMS-based PUs with MPEG grafts, which have few hard segments and a distinct PEG phase, exhibited the least platelet adhesion among the polymer samples tested.
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Affiliation(s)
- J H Park
- Center for Biomaterials and Biotechnology, Department of Materials Science and Engineering, Kwangju Institute of Science and Technology, South Korea
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47
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Han DK, Park KD, Hubbell JA, Kim YH. Surface characteristics and biocompatibility of lactide-based poly(ethylene glycol) scaffolds for tissue engineering. J Biomater Sci Polym Ed 1998; 9:667-80. [PMID: 9686334 DOI: 10.1163/156856298x00082] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Novel lactide-based poly(ethylene glycol) (PEG) polymer networks (GL9-PEGs) were prepared by UV copolymerization of a glycerol-lactide triacrylate (GL9-Ac) with PEG monoacrylate (PEG-Ac) to use as scaffolds in tissue engineering, and the surface properties and biocompatibility of these networks were investigated as a function of PEG molecular weight and content. Analysis by ATR-FTIR and ESCA revealed that PEG was incorporated well within the GL9-PEG polymer networks and was enriched at the surfaces. From the results of SEM, AFM, and contact angle analyses, GL9-PEG networks showed relatively rough and irregular surfaces compared to GL9 network, but the mobile PEG chains coupled at their termini were readily exposed toward the aqueous environment when contacting water such that the surfaces became smoother and more hydrophilic. This reorientation and increase in hydrophilicity were more extensive with increasing PEG molecular weight and content. As compared to GL9 network lacking PEG, protein adsorption as well as platelet and S. epidermidis adhesion to GL9-PEG networks were significantly reduced as the molecular weight and content of PEG was increased, indicating that GL9-PEG networks are more biocompatible than the GL9 network due to PEG's passivity. Based on the physical and biological characterization reported, the GL9-PEG materials would appear to be interesting candidates as matrices for tissue engineering.
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Affiliation(s)
- D K Han
- Biomaterials Research Center, Korea Institute of Science and Technology, Seoul, Korea
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48
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Lee JH, Ju YM, Lee WK, Park KD, Kim YH. Platelet adhesion onto segmented polyurethane surfaces modified by PEO- and sulfonated PEO-containing block copolymer additives. J Biomed Mater Res 1998; 40:314-23. [PMID: 9549627 DOI: 10.1002/(sici)1097-4636(199805)40:2<314::aid-jbm17>3.0.co;2-l] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Polyethylene oxide (PEO) surfaces were prepared by the addition of PEO- and sulfonated PEO-containing amphiphilic block copolymers as surface-modifying additives in a segmented polyurethane (PU). PEO-PPO-PEO triblock copolymers (Pluronics) with different PEO chain lengths (from 2 to 80) were used as additives. The prepared film surfaces were characterized by the measurement of dynamic water contact angles and electron spectroscopy for chemical analysis. It was observed that the PU films containing 10 wt% of PEO additives were surface-saturated with the additives regardless of their PEO chain length, but the PEO chains were more projected from the film surfaces containing the additives with longer PEO chains. The water absorption of the films increased largely with the increasing PEO chain length of the additives. The addition of PEO additives produced film surfaces that were in a gel-like state. The films demonstrated some extraction of the PEO additives. However, the additives with higher molecular weights were entrapped more stably into the PU matrix. The mechanical properties (tensile strength and elongation) of the films were changed by the addition of PEO additives, but the differences were not significant compared to the control PU. The platelet adhesion on the film surfaces decreased with increasing PEO chain length of the additives. The film surface containing additives with long PEO chains (chain length of 80) was particularly effective in preventing platelet adhesion. The effect of negatively charged sulfonate groups on the prevention of platelet adhesion appeared only on the film surfaces containing additives with short PEO chains. For longer PEO chains, the chain mobility effect was more dominant than the negative charge effect on the prevention of platelet adhesion.
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Affiliation(s)
- J H Lee
- Department of Macromolecular Science, Hannam University, Taejon, Korea
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49
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Abstract
Polyurethane surface was modified with poly(ethylene glycol) (mol. wt. 1000, PEG1k) carrying terminal hydroxyl, amino and sulfonate groups, poly(ethylene glucol) (mol. wt. 3350, PEG3.4k) and PEG3.4k-Heparin, respectively. These surfaces were investigated for bacterial adhesion using S. epidermidis and E. coli in tryptic soya broth (TSB), brain heart infusion (BHI), and human plasma. All PEG modified surfaces reduced bacterial adhesion significantly and the adhesion level differs depending on surfaces as well as media. In the case of PEG1k surfaces, no reduction of S. epidermidis adhesion was demonstrated in TSB media, regardless of terminal functional groups of PEG1k. However, adhesion in plasma was reduced to the different degree, depending on terminal groups of PEG1k (least adhesion on sulfonated PEG surface). Relatively longer PEG surface (PEG3.4k) and PEG3.4k-heparin surface minimized bacterial adhesion in both media. In the case of E. coli adhesion, significant reduction in adherent bacteria was observed on all PEG1k, PEG3.4k, and PEG-heparin surfaces in both media compared to controls. In contrast, no reduction in bacterial adhesion was demonstrated on poly(propylene glycol) (PPG1k) grafted PU surface as compared to control PU. These results suggest that surface modification with PEG1k-SO3, PEG3.4k and PEG3.4k-heparin seems to be effective for prevention of bacterial adhesion and subsequent infection.
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Affiliation(s)
- K D Park
- Biomaterials Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul, South Korea.
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50
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Abstract
Sulfonated poly(ethylene oxide) (PEO-SO3)-grafted polyurethane (PU) copolymer (PU-PEO-SO3) was developed for utilization as a material for biomedical applications. Its bulk properties and biocompatibility were investigated and the results were compared to those of PU and PU-PEO (not sulfonated). PU-PEO-SO3 copolymer showed higher water uptake than PU and PU-PEO, indicative of increased hydrophilicity due to the grafting of PEO-SO3. Compared with PU, PU-PEO-SO3 displayed lower glass transition temperature (Tg) and melting endotherm from DSC analysis, suggesting the increase of microphase separation and the suppression of hard-segment packing. PU-PEO-SO3 had practically similar mechanical properties to PU, indicating that the chemical modification of PU was accomplished without reducing its bulk properties. From the results of biocompatibility tests, PU-PEO-SO3 copolymer showed significantly lower adhesion of platelets and S. epidermidis than PU control and PU-PEO. In addition, the platelet factor 4 (PF4) released from platelets was the lowest in PU-PEO-SO3 among the test materials. PU-PEO-SO3 copolymer, which has excellent mechanical properties and biocompatibility, is expected to be useful as coating, molding, and blending materials for artificial organs and medical devices.
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Affiliation(s)
- D K Han
- Biomaterials Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul
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