Publications by authors named "Changsik Park"

Diabetic foot ulcer represents the primary cause of hospital admissions, amputations, and mortality in diabetic patients. The development of diabetic foot ulcers is influenced by peripheral neuropathy, infection, and ischemia, with diabetes contributing to peripheral artery disease. Free tissue transfer combined with revascularisation of the lower extremity provides the potential opportunity for limb salvage in individuals with lower extremity defects due to critical limb ischemia and diabetic foot.

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Background:  Among the many factors involved in reconstructive microsurgery, identifying a good recipient vessel is one of the key elements leading to a successful result.

Methods:  Multiple modalities have been used to identify recipient vessels from simple palpation of axial arteries to hand-held Doppler, duplex ultrasound, computed tomography angiograms, and other advanced techniques. Although these various modalities bring their own unique advantages, using the duplex ultrasound can provide far superior and real-time information based on the anatomy and physiology of the recipient vessel.

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Background:  The local flaps, especially perforator and keystone flaps, are used as first-line treatment option in reconstruction of small tomoderate-sized defect of the extremity. However, the high complication rate associated with these flaps may hinder this usage.

Methods:  This article reviews the technical and clinical aspect of using color duplex ultrasound )CDU) in the preoperative, intraoperative, and postoperative period for propeller and keystone flaps.

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c-Met, as a receptor expressed on the cell membrane, contributes to the growth and metastasis of tumors, as well as angiogenesis, mainly through the hepatocyte growth factor (HGF)/c-Met axis during tumor progression. Although several c-Met inhibitors, including small molecules and monoclonal antibody inhibitors, are currently being investigated, their clinical outcomes have not been promising. Development of an antibody-drug conjugate (ADC) against c-Met could be an attractive therapeutic strategy that would provide superior antitumor efficacy with broad-spectrum c-Met expression levels.

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Successful reconstruction of diabetic ulcers using free flap surgery can prevent further amputation and promote limb salvage to maintain normal gait of the patient and increase the quality of life after surgery. To minimize the postoperative complication and days of stay in hospital, surgeons should thoroughly investigate the risk factors and underlying conditions, including the general condition and local factors.

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Background: Accurate prediction of fall likelihood is advantageous for instituting fall prevention program in rehabilitation facilities.

Objective: This study was designed to determine the clinical measures, which can predict the risk of fall events in a rehabilitation hospital.

Methods: Medical records of 166 patients (114 males and 52 females) who were hospitalized in an adult inpatient unit of a rehabilitation hospital were retrospectively analyzed for this study.

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Background:  Successful lower extremity reconstruction using free flaps begins by identifying a good recipient vessel and understanding the surrounding environment of the defect.

Methods:  One should consider multiple factors when selecting the recipient vessel such as the status of the axial arteries, trying to preserve flow as much as possible, extent and severity of the defect, and ultimately what type of anastomosis will be ideal.

Results:  Multiple factors of importance are reviewed and show the relevance in decision making and provide an algorithm.

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[Purpose] To establish the test-retest reliabilities, minimal detectable change of the Short form Barthel Index and associations with stroke-specific impairments. [Subjects and Methods] The Short form-Barthel Index assessment was tested on 24 chronic stroke patients twice, 7 days apart. A relative reliability index (ICC), Weighted Kappa Coefficients was used to examine the level of agreement of test-retest reliability for SF-BI, Absolute reliability indices, including the standard error of measurement and the minimal detectable change.

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[Purpose] The purpose of this study was to evaluate the functional effects of additional action observational training for functional electrical stimulation treatment on weight bearing, stability and gait velocity of hemiplegic patients. [Subjects and Methods] Twenty subjects were randomized into two groups. Subjects more than six months post-stroke participated.

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Reprogramming errors, which appear frequently in cloned animals, are reflected by aberrant gene expression. We previously reported the aberrant expression of TIMP-2 and PBEF in cloned placenta and differential expression of PBEF genes during pregnancy. To examine the epigenetic modifications that regulate dynamic gene expression in developing placentae, we herein analyzed the mRNA and protein expression levels of PBEF and TIMP-2 in the placentae of normal mice during pregnancy and then examined potential correlations with epigenetic modifications.

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Dihydroavenanthramide D (DHAvD) is a synthetic analog to naturally occurring avenanthramide, which is the active component of oat. Previous study demonstrates that DHAvD strongly inhibits activation of nuclear factor-kappa B (NF-κB), which is a major component in cancer cell invasion. The present study investigated whether DHAvD can modulate MMP-9 expression and cell invasion in MCF-7 human breast cancer cells.

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Xenotransplantation of porcine organs has the potential to help overcome the severe shortage of human tissues and organs available for human transplantation. However, numerous hurdles such as immune-mediated xenograft rejection remain before clinical xenotransplantation. In this study, we elucidated the role of human TNF-alpha-inducing factor, Interleukin-32 (IL-32), in porcine kidney cells (PK-15) during cell-mediated rejection by examining host cell responses.

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Proteolysis of ubiquitinated sperm and oocyte proteins by the 26S proteasome is necessary for the success of mammalian fertilization, including but not limited to acrosomal exocytosis and sperm-zona pellucida (ZP) penetration. The present study examined the role of PSMD4, an essential non-ATPase subunit of the proteasomal 19S regulatory complex responsible for proteasome-substrate recognition, in sperm-ZP penetration during porcine fertilization in vitro (IVF). Porcine sperm-ZP penetration, but not sperm-ZP binding, was blocked in the presence of a monoclonal anti-PSMD4 antibody during IVF.

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The 26S proteoasome is a multi-subunit protease specific to ubiquitinated substrate proteins. It is composed of a 20S proteasomal core with substrate degradation activity, and a 19S regulatory complex that acts in substrate recognition, deubiquitination, priming and transport to the 20S core. Inhibition of proteolytic activities associated with the sperm acrosome-borne 20S core prevents fertilization in mammals, ascidians and echinoderms.

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The aim of the present study was to investigate the effect of erdosteine on renal reperfusion injury. Twelve male Landrace and Yorkshire mixed pigs were randomly divided into two groups: untreated control group (I/R), erdosteine treated group (I/R + erdosteine). Each group is composed of six pigs, and the pigs were unilaterally nephrectomized and their contralateral kidneys were subjected to 30 min of renal pedicle occlusion.

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Three indirect enzyme-linked immunosorbent assays (iELISA) based on the North American like (NA-like), European like (EU-like) and co-expressed NA- and EU-like recombinant nucleocapsid proteins (N-protein) of porcine reproductive and respiratory syndrome virus (PRRSV) were validated for the detection of the antibodies in porcine sera. A total of 422 serum samples from unvaccinated pigs were tested. The cut-off value was optimized by a two-graph receiver operating characteristics analysis at a 95% confidence level.

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Article Synopsis
  • * The 26S proteasome, which is present on the sperm acrosomal surface, requires ATP for the proteolytic degradation of ubiquitinated proteins essential for successful fertilization.
  • * Treatment with apyrase, an enzyme that depletes sperm-surface associated ATP, significantly reduced fertilization rates in porcine IVF, indicating that ATP is necessary for maintaining the integrity of the proteasomal 19S complex, while blocking proteasomal activity with MG132 had different outcomes.
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The objective of this study was to investigate the potential of various formulation strategies to achieve sustained release of the peptide, from injectable poly(D,L-lactide-co-glycolide) (PLGA) and d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) microparticles. The microparticles were prepared by a solvent evaporation method. Peptide loaded PLGA microparticles exhibited a pronounced initial burst release (22.

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Streptolysin O (SLO) is a known bacterial protein that forms very large pores in the plasma membranes of mammalian cells. SLO has been used in the delivery of proteins into living cells following permeabilization. The objective of this study was to investigate the effects of SLO treatment in donor cells that generate pores in the plasma membrane during in vitro development of porcine reconstructed embryos.

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Although the fertilizing ability of spermatozoa is greatly reduced after freezing, complete understanding of alterations induced by cryopreservation has not been elucidated. The present study evaluates the effects of cryopreservation on the Ca2+ handling of boar spermatozoa using several sperm activators. Intracellular Ca2+ signals from single spermatozoa were measured using confocal Ca2+ imaging of unfrozen samples and of other spermatozoa after having been frozen.

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The resumption of oocyte meiosis in mammals encompasses the landmark event of oocyte germinal vesicle (GV) breakdown (GVBD), accompanied by the modification of cell-to-cell communication and adhesion between the oocyte and surrounding cumulus cells. The concomitant cumulus expansion relies on microfilament-cytoskeletal remodeling and extracellular matrix (ECM) deposition. We hypothesized that this multifaceted remodeling event requires substrate-specific proteolysis by the ubiquitin-proteasome pathway (UPP).

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Tumor necrosis factor receptor (TNFR)-associated factors (TRAFs) are key adaptor molecules in the TNFR-signaling complexes that promote a wide variety of signaling cascades including cell proliferation, activation, differentiation, and apoptosis. TRAF-interacting protein (TRIP) is required for the inhibitory regulation of TNF-induced NF-kappaB signaling via the TNFR/TRAF-signaling complexes in vitro. TRIP also directly interacts with the familial cylindromatosis tumor suppressor gene (CYLD) and negatively regulates NF-kappaB activation in vitro.

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The 26S proteasome, which is a multi-subunit protease with specificity for substrate proteins that are postranslationally modified by ubiquitination, has been implicated in acrosomal function and sperm-zona pellucida (ZP) penetration during mammalian fertilization. Ubiquitin C-terminal hydrolases (UCHs) are responsible for the removal of polyubiquitin chains during substrate priming for proteasomal proteolysis. The inhibition of deubiquitination increases the rate of proteasomal proteolysis.

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TNF-alpha plays a variety of biological functions such as apoptosis, inflammation and immunity. PTEN also has various cellular function including cell growth, proliferation, migration and differentiation. Thus, possible relationships between the two molecules are suggested.

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Various cell types in higher multicellular organisms are genetically homogenous, but are functionally and morphologically heterogeneous due to the differential expression of genes during development, which appears to be controlled by epigenetic mechanisms. However, the exact molecular mechanisms that govern the tissue-specific gene expression are poorly understood. Here, we show that dynamic changes in histone modifications and DNA methylation in the upstream coding region of a gene containing the transcription initiation site determine the tissue-specific gene expression pattern.

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