Publications by authors named "Soo-Hyeon Kim"

64 Publications

High removal efficiency of industrial toxic compounds through stable catalytic reactivity in water treatment system.

Chemosphere 2022 Jan 9;287(Pt 2):132204. Epub 2021 Sep 9.

Division of Material Analysis and Research, Korea Basic Science Institute, Gwahak-ro, Yuseong-gu, Daejeon, 34133, Republic of Korea. Electronic address:

We identified optimal conditions for the disposal of high concentration of organic contaminants within a short time using a hybrid advanced oxidation process (AOP) combining various oxidizing agents. Plasma-treated water (PTW) containing many active species, that play dominant roles in the degradation of organic substances like hydroxyl radicals, atomic oxygen, ozone, and hydrogen peroxide, was used in this study as a strategy to improve degradation performance without the use of expensive chemical reagents like hydrogen peroxide. In particular, the optimal decomposition conditions using PTW, which were combined with 10 mg/h ozone, 2 g/L iron oxide, and 4 W UV light, demonstrated excellent removal abilities of a high concentration of reactive black 5 (RB5; 100 mg/L, >99%, [k] = 4.15 h) and tetracycline (TC; 10 mg/L, >96.5%, [k] = 3.35 h) for 25 min, approximately 1.5 times higher than that without PTW (RB5; 100 mg/L, 94%, [k] = 2.80 h). These results confirmed that the production of strong reactive hydroxyl radicals from the decomposition process, as well as various reactive species included in PTW efficiently attacked pollutant substances, resulting in a higher removal rate. This suggests that a water treatment system with this optimal condition based on complex AOP systems using PTW could be useful in critical environmental and biomedical applications.
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http://dx.doi.org/10.1016/j.chemosphere.2021.132204DOI Listing
January 2022

High-throughput sorting of nanoliter droplets enabled by a sequentially addressable dielectrophoretic array.

Electrophoresis 2021 Oct 2. Epub 2021 Oct 2.

Department of Chemistry, The University of Tokyo, Tokyo, Japan.

Droplet microfluidics has emerged as a powerful tool for a diverse range of biomedical and industrial applications such as single-cell analysis, directed evolution, and metabolic engineering. In these applications, droplet sorting has been effective for isolating small droplets encapsulating molecules, cells, or crystals of interest. Recently, there is an increased interest in extending the applicability of droplet sorting to larger droplets to utilize their size advantage. However, sorting throughputs of large droplets have been limited, hampering their wide adoption. Here, we report our demonstration of high-throughput fluorescence-activated droplet sorting of 1 nL droplets using an upgraded version of the sequentially addressable dielectrophoretic array (SADA), which we reported previously. The SADA is an array of electrodes that are individually and sequentially activated/deactivated according to the speed and position of a droplet passing nearby the array. We upgraded the SADA by increasing the number of driving electrodes constituting the SADA and incorporating a slanted microchannel. By using a ten-electrode SADA with the slanted microchannel, we achieved fluorescence-activated droplet sorting of 1 nL droplets at a record high throughput of 1752 droplets/s, twice as high as the previously reported maximum sorting throughput of 1 nL droplets.
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http://dx.doi.org/10.1002/elps.202100057DOI Listing
October 2021

Canine mammary cancer in overweight or obese female dogs is associated with intratumoral microvessel density and macrophage counts.

Vet Pathol 2021 Sep 21:3009858211040481. Epub 2021 Sep 21.

Konkuk University, Gwangjin-gu, Seoul, Republic of Korea.

Obesity is a major health condition owing to its effects on chronic diseases and cancers in humans, but little information is available regarding the role of obesity in canine mammary cancer (CMC). In the present study, we performed immunohistochemistry to investigate the effect of obesity on CMC by analyzing the number of tumor-associated macrophages, intratumoral microvessel density (iMVD), and the expression of prognostic factors including epidermal growth factor receptor (EGFR), cyclooxygenase 2 (COX-2), and Ki67 in CMC specimens. These data were compared in CMC specimens from lean or ideal body weight (Group 1) versus overweight or obese (Group 2) female dogs ( = 60 for each group). Associations between obesity status and histologic characteristics, such as histologic subtype, grading, and lymphatic invasion, were also investigated. Compared with lean or ideal body weight dogs, TAM (tumor-associated macrophage) counts ( < .005) and iMVD ( < .001) were significantly higher in overweight or obese dogs. CMC specimens of dogs in the overweight or obese group also showed higher histologic grade ( < .001). In addition, although no association was found between obesity status and either COX-2 or EGFR expression, Ki67 expression was greater in CMC specimens of overweight or obese dogs ( < .005). The results of this study suggest that obesity may influence CMC development and progression, being associated with higher histologic grade, greater infiltration of TAMs, and increased tumor angiogenesis.
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http://dx.doi.org/10.1177/03009858211040481DOI Listing
September 2021

Arginase-1 and P-glycoprotein are downregulated in canine hepatocellular carcinoma.

J Vet Sci 2021 Sep 12;22(5):e61. Epub 2021 Jul 12.

Department of Veterinary Pathology, Small Animal Diagnostic Center, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.

Background: Hepatocellular carcinoma is the most common primary hepatic malignancy in humans and dogs. Several differentially expressed molecules have been studied and reported in human hepatocellular carcinoma and non-neoplastic liver lesions. However, studies on the features of canine hepatocellular carcinoma are limited, especially related to the differential characteristics of neoplastic and non-neoplastic lesions.

Objectives: The study's objective was 1) to examine and evaluate the expression of arginase-1, P-glycoprotein, and cytokeratin 19 in canine liver tissues and 2) to investigate the differential features of hepatocellular carcinomas, liver tissue with non-neoplastic lesions, and paracancerous liver tissues in dogs.

Methods: The expression levels of three markers underwent immunohistochemical analysis in 40 non-neoplastic liver tissues, 32 hepatocellular carcinoma tissues, and 11 paracancerous liver tissues. Scoring of each marker was performed semi-quantitatively.

Results: Arginase-1 and P-glycoprotein were significantly downregulated in hepatocellular carcinoma, compared with hepatic tissues with non-neoplastic diseases ( < 0.001). Expression levels of arginase-1 and P-glycoprotein were also significantly lower in hepatocellular carcinoma than in paracancerous liver tissues (arginase-1, 0.0195; P-glycoprotein, 0.047). Few cytokeratin 19-positive hepatocytes were detected and only in one hepatocellular carcinoma and one cirrhotic liver sample.

Conclusions: The results of this study suggest that downregulation of arginase-1 and P-glycoprotein is a feature of canine hepatocellular carcinoma; thus, those markers are potential candidates for use in differentiating hepatocellular carcinomas from non-neoplastic liver lesions in dogs.
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http://dx.doi.org/10.4142/jvs.2021.22.e61DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8460467PMC
September 2021

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) loss in canine mammary carcinoma.

Vet Comp Oncol 2021 Aug 23. Epub 2021 Aug 23.

Department of Veterinary Pathology, Small Animal Diagnostic Center, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.

Escaping apoptosis is a hallmark of cancer. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), a central molecule that regulates the extrinsic apoptotic pathway, has been widely investigated in human oncology; however, investigations focusing on the endogenous expression of TRAIL in canine tumours are lacking. Therefore, we aimed to examine the expression of endogenous TRAIL in canine mammary tumours and analysed its correlation with downstream molecules Fas-associated protein with death domain (FADD) and caspase-3, and to the apoptotic index. A total of 147 samples, classified as normal mammary gland (n = 9), mammary adenoma (n = 30), low-grade carcinoma (n = 42) and high-grade carcinoma (n = 66), were included in the immunohistochemical analyses, and 43 samples with sufficient levels of RNA were analysed via RNA in situ hybridization and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay. In immunohistochemistry, TRAIL protein expression was significantly decreased in high-grade carcinoma compared to those in normal mammary gland and adenoma, with similar downregulation of TRAIL mRNA expression. Also, FADD and caspase-3 expression positively correlated with TRAIL expression. However, the apoptotic index was paradoxically elevated in high-grade tumours. Overall, these results suggest that the loss of TRAIL accompanied by dysregulation of TRAIL-induced extrinsic apoptotic pathway molecules could affect malignant progression of canine mammary tumours.
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http://dx.doi.org/10.1111/vco.12767DOI Listing
August 2021

Dysregulation of PI3K/Akt/PTEN Pathway in Canine Mammary Tumor.

Animals (Basel) 2021 Jul 12;11(7). Epub 2021 Jul 12.

Department of Veterinary Pathology, College of Veterinary Medicine, Konkuk University, Seoul 05025, Korea.

The PI3K/Akt/PTEN axis is one of the most important signaling pathways in tumorigenesis. Recently, mutation of PIK3CA has been highlighted due to the similarities of mutational hotspots in both dogs and humans. PIK3CA H1047R (c.3140A > G) has been discovered as the most common mutational hot spot in canine mammary tumor in recent studies, while the feature of PIK3CA-mutated canine mammary tumor is obscure.

Methods: A total of 83 mammary samples classified as normal ( = 13), adenoma ( = 25), low-grade carcinoma ( = 21), and high-grade carcinoma ( = 24) were included in this study. Genomic DNA from each sample was extracted, amplified by conventional PCR, and analyzed through Sanger sequencing. Analysis for the expression of PIK3CA, Akt, p-Akt, and PTEN was performed by immunohistochemistry, and of Akt2 by RNA in situ hybridization.

Results: PIK3CA H1047R mutation was detected in 14.3% (10/70) of tumor samples. Dysregulation of p-Akt, Akt2, and PTEN was observed in mammary tumor samples, but only PTEN dysregulation was associated with PIK3CA H1047R mutation.

Conclusions: The present study showed that dysregulation of components in the PI3K/Akt/PTEN pathway is a feature of canine mammary tumors, but this dysregulation is not directly correlated to the PIK3CA H1047R mutation except for PTEN expression.
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http://dx.doi.org/10.3390/ani11072079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8300234PMC
July 2021

Impact of Histological Subtype on Survival in Canine Mammary Carcinomas: a Retrospective Analysis of 155 Cases.

J Comp Pathol 2021 Jul 7;186:23-30. Epub 2021 Jun 7.

Department of Veterinary Pathology, Small Animal Tumor Diagnostic Center, Department of Veterinary Surgery, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea. Electronic address:

Canine mammary carcinoma (CMC) is the most common type of neoplasm in intact female dogs. While a previous study in Western countries validated the 2011 classification as an independent prognostic indicator in CMC, its role in CMC prognostication in Asian countries such as Korea remains unclear. In the present study, we estimate the survival rates in CMC types defined by the 2011 classification, elucidate the prognostic significance of the histological subtype and grade and that of the lymphatic invasion status in CMC, and validate the 2011 classification as an independent prognostic indicator in a large cohort of CMCs (excluding cases of multicentric CMCs). A total of 155 CMC cases retrieved from archived formalin-fixed, paraffin-embedded tissues, along with 2-year follow-up data, were retrospectively analysed. A significant association was found between the histological subtype of the 2011 classification and the tumour-specific survival. Carcinosarcoma, adenosquamous carcinoma and anaplastic carcinoma subtypes were associated with the poorest prognosis. Dogs with comedocarcinoma and solid carcinoma followed a disease course that was more aggressive than that observed in dogs with a carcinoma arising in a benign mixed tumour. Moreover, age, histological grade and lymphatic invasion status significantly correlated with tumour-specific survival in univariate analysis. In multivariate analysis, histological subtype, age and lymphatic invasion status remained independent prognostic factors for CMC.
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http://dx.doi.org/10.1016/j.jcpa.2021.05.002DOI Listing
July 2021

Soluble Prokaryotic Overexpression and Purification of Human GM-CSF Using the Protein Disulfide Isomerase b'a' Domain.

Int J Mol Sci 2021 May 17;22(10). Epub 2021 May 17.

Department of Physiology, Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, Korea.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a member of the colony-stimulating factor (CSF) family, which functions to enhance the proliferation and differentiation of hematopoietic stem cells and other hematopoietic lineages such as neutrophils, dendritic cells, or macrophages. These proteins have thus generated considerable interest in clinical therapy research. A current obstacle to the prokaryotic production of human GM-CSF (hGM-CSF) is its low solubility when overexpressed and subsequent complex refolding processes. In our present study, the solubility of hGM-CSF was examined when combined with three N-terminal fusion tags in five strains at three different expression temperatures. In the five strains BL21 (DE3), ClearColi BL21 (DE3), LOBSTR, SHuffle T7 and Origami2 (DE3), the hexahistidine-tagged hGM-CSF showed the best expression but was insoluble in all cases at each examined temperature. Tagging with the maltose-binding protein (MBP) and the b'a' domain of protein disulfide isomerase (PDIb'a') greatly improved the soluble overexpression of hGM-CSF at 30 °C and 18 °C. The solubility was not improved using the Origami2 (DE3) and SHuffle T7 strains that have been engineered for disulfide bond formation. Two conventional chromatographic steps were used to purify hGM-CSF from the overexpressed PDIb'a'-hGM-CSF produced in ClearColi BL21 (DE3). In the experiment, 0.65 mg of hGM-CSF was isolated from a 0.5 L flask culture of these and showed a 98% purity by SDS-PAGE analysis and silver staining. The bioactivity of this purified hGM-CSF was measured at an EC of 16.4 ± 2 pM by a CCK8 assay in TF-1 human erythroleukemia cells.
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http://dx.doi.org/10.3390/ijms22105267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8156066PMC
May 2021

EGFR Overexpression and Sequence Analysis of KRAS, BRAF, and EGFR Mutation Hot Spots in Canine Intestinal Adenocarcinoma.

Vet Pathol 2021 07 30;58(4):674-682. Epub 2021 Apr 30.

34965 Konkuk University, Gwangjin-gu, Seoul, Republic of Korea.

Epidermal growth factor receptor (EGFR) is overexpressed in many human colorectal cancers and anti-EGFR agents are employed as immunotherapies. However, , , and gene mutations can influence the activity of the anti-EGFR agents. We evaluated EGFR expression at protein and mRNA levels in canine intestinal adenocarcinomas using immunohistochemistry (IHC) and RNA in situ hybridization (RNA-ISH). We also investigated the mutation status of , , and to aid the development of anti-EGFR agents for canine intestinal adenocarcinoma. EGFR expression was highest in adenocarcinoma, followed by intramucosal neoplasia (adenoma and in situ carcinoma), and nonneoplastic canine intestinal tissue, at both protein ( = .000) and mRNA ( = .005) levels. The , , and genes showed wild-type sequences at the mutation hot spots in all 13 specimens. Thus, EGFR might serve as a promising diagnostic marker in canine intestinal adenocarcinoma, and further studies would be needed to develop EGFR-targeted anticancer therapies.
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http://dx.doi.org/10.1177/03009858211009778DOI Listing
July 2021

CDX-2 Protein and mRNA Expression in Canine Intestinal Adenocarcinoma.

J Comp Pathol 2021 Apr 26;184:24-30. Epub 2021 Feb 26.

Department of Veterinary Pathology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea. Electronic address:

Caudal-related homeobox transcription factor 2 (CDX-2) is a specific cell marker employed in the diagnosis of human colorectal cancer. Reduced CDX-2 expression is associated with several indicators of poor prognosis in human colorectal cancer. In the present study, CDX-2 protein levels were evaluated and patterns of CDX-2 mRNA accumulation are described for the first time in canine intestinal adenocarcinoma (CIA). Canine intestinal epithelial biopsies from 21 CIAs and 14 non-neoplastic control tissues were retrospectively evaluated for CDX-2 expression and CDX-2 mRNA levels by immunohistochemistry and RNA in-situ hybridization (RNA-ISH), respectively. The mean percentage or intensity of expression was decreased in the CIA group (P = 0.000). RNA-ISH demonstrated a significant correlation between the decrease in CDX-2 mRNA levels and CDX-2 protein expression (P = 0.000). CDX-2 downregulation, in terms of protein as well as mRNA levels, may serve as a diagnostic marker in CIA.
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http://dx.doi.org/10.1016/j.jcpa.2021.01.010DOI Listing
April 2021

Surface-Enhanced Raman Scattering-Based Dual-Flow Lateral Flow Assay Sensor for the Ultrasensitive Detection of the Thyroid-Stimulating Hormone.

Anal Chem 2021 05 20;93(17):6673-6681. Epub 2021 Apr 20.

Department of Chemistry, Chung-Ang University, Seoul 06974, South Korea.

The surface-enhanced Raman scattering (SERS)-based lateral flow assay (LFA) strip has been considered a high-sensitivity sensor that can overcome the low sensitivity and the difficulty of quantitative analysis problems inherent in the colorimetric LFA sensor. In the SERS-based LFA strip reported so far, a liquid sample flows through the nitrocellulose membrane in a single pathway. In some cases, however, this single-flow approach still has a limitation in detection sensitivity. This study developed a conceptually new SERS-based dual-flow LFA sensor to improve the detection sensitivity in a single-flow LFA sensor. First, a 25 nm Raman reporter-labeled gold nanoparticle (AuNP) solution flowed through one way, and a 45 nm AuNP solution continuously flowed through another path. This sequential flow of two different AuNP solutions enables forming additional bright hot spots between 25 and 45 nm AuNPs in the test line, and the SERS signal is strongly enhanced. Using this SERS-based dual-flow LFA sensor, it was possible to detect thyroid-stimulating hormone less than 0.5 μIU/mL that cannot be measured with a SERS-based single-flow LFA sensor.
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http://dx.doi.org/10.1021/acs.analchem.0c05336DOI Listing
May 2021

Dynamics of D-amino acid oxidase ain kidney epithelial cells under amino acid starvation.

J Biochem 2021 Sep;170(1):119-129

Division of Enzyme Pathophysiology, Institute for Enzyme Research, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan.

D-amino acid oxidase (DAO) is a flavoenzyme catalyzing the oxidation of D-amino acid (AA)s. In the kidney, its expression is detected in proximal tubules, and DAO is considered to play a role in the conversion of D-form AAs to α-keto acids. LLC-PK1 cells, a pig renal proximal tubule cell line, were used to elucidate the regulation of DAO protein synthesis and degradation. In this study, we showed that trypsinization of LLC-PK1 cells in culture system rapidly reduced the intracellular DAO protein level to ∼33.9% of that before treatment, even within 30 min. Furthermore, we observed that the DAO protein level was decreased when LLC-PK1 cells were subjected to AA starvation. To determine the degradation pathway, we treated the cells with chloroquine and MG132. DAO degradation was found to be inhibited by chloroquine, but not by MG132 treatment. We next examined whether or not DAO was degraded by autophagy. We found that AA starvation led to an increased accumulation of LC3-II, suggesting that DAO protein is degraded by autophagy due to AA starvation conditions. Furthermore, treatment with cycloheximide inhibited DAO protein degradation. Taken together, DAO protein is degraded by autophagy under starvation. The present study revealed the potential dynamics of DAO correlated with renal pathophysiology.
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http://dx.doi.org/10.1093/jb/mvab029DOI Listing
September 2021

Morphological Manipulation of DNA Gel Microbeads with Biomolecular Stimuli.

Nanomaterials (Basel) 2021 Jan 22;11(2). Epub 2021 Jan 22.

LIMMS, CNRS-Institute of Industrial Science, UMI 2820, University of Tokyo, Tokyo 153-8505, Japan.

Hydrogels are essential in many fields ranging from tissue engineering and drug delivery to food sciences or cosmetics. Hydrogels that respond to specific biomolecular stimuli such as DNA, mRNA, miRNA and small molecules are highly desirable from the perspective of medical applications, however interfacing classical hydrogels with nucleic acids is still challenging. Here were demonstrate the generation of microbeads of DNA hydrogels with droplet microfluidic, and their morphological actuation with DNA strands. Using strand displacement and the specificity of DNA base pairing, we selectively dissolved gel beads, and reversibly changed their size on-the-fly with controlled swelling and shrinking. Lastly, we performed a complex computing primitive-A Winner-Takes-All competition between two populations of gel beads. Overall, these results show that strand responsive DNA gels have tantalizing potentials to enhance and expand traditional hydrogels, in particular for applications in sequencing and drug delivery.
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http://dx.doi.org/10.3390/nano11020293DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7912653PMC
January 2021

Ovarian adenocarcinoma with metastases in a white rhinoceros.

J Vet Diagn Invest 2021 Mar 10;33(2):366-369. Epub 2021 Jan 10.

Department of Veterinary Pathology, College of Veterinary Medicine, Konkuk University, Seoul, Korea.

A 36-y-old white rhinoceros () was presented with respiratory distress, sanguineous vaginal exudate, and anorexia. The clinical signs progressed over 40 d, and the rhinoceros died. Autopsy revealed significant ascites; a unilateral, 12.5-cm diameter, polypoid mass in the left ovary; a white, firm transmural mass in the right uterine horn; a white, friable mass in the lung; and white-to-tan, friable small nodules in the diaphragm. Histologic examination revealed similar neoplastic cells in the masses in all 4 locations, composed predominantly of epithelial cells proliferating in a tubulopapillary pattern with significant nuclear atypia and numerous atypical mitotic figures (18-42 per 2.37 mm). Immunohistochemistry for CK7 (cytokeratin 7) and CK20 (cytokeratin 20) suggest that the ovarian, pulmonary, and diaphragmatic lesions were of ovarian origin and that the ovary was the primary tumor site.
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http://dx.doi.org/10.1177/1040638720986789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953103PMC
March 2021

In situ c-KIT mRNA quantification of canine cutaneous mast cell tumours and its relationship to prognostic factors.

Vet Comp Oncol 2021 Mar 3;19(1):132-139. Epub 2020 Nov 3.

Department of Veterinary Pathology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.

Cutaneous mast cell tumours (MCTs) are the most frequent malignant skin tumours in dogs. Mutations in the c-KIT proto-oncogene are correlated with the pathogenesis and aggressiveness of MCTs. To date, studies have focused on c-KIT mutations and KIT protein localization, with a general lack of mRNA-level analyses. In this study, c-KIT mRNA expression was investigated in canine MCTs by RNA in situ hybridization (RNA-ISH). Furthermore, we evaluated associations between c-KIT mRNA expression and the histological grade, KIT immunohistochemical staining pattern and other clinicopathological parameters. c-KIT mRNA expression was observed in all MCT samples, appearing as clusters of dots in the cytoplasm of neoplastic cells. A significant correlation was detected between c-KIT mRNA expression (quantified according to the H-score and the percentage of positive cells) and the histological grade (determined using two-and three-tier grading systems; P < .05). We also found a significant positive correlation (all P < .05) between c-KIT mRNA expression and the proliferation indices (mitotic index, Ki-67, and Ag67). However, no significant associations with c-KIT expression from RNA-ISH were found with respect to different KIT staining patterns. Overall, these results demonstrate that c-KIT mRNA expression might be an additional tool for measuring the c-KIT status in canine cutaneous MCTs and could serve as a potential prognostic factor. Further studies should evaluate the prognostic significance of c-KIT mRNA expression in a large and uniform cohort of canine MCTs.
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http://dx.doi.org/10.1111/vco.12650DOI Listing
March 2021

P219L substitution in human D-amino acid oxidase impacts the ligand binding and catalytic efficiency.

J Biochem 2020 Nov;168(5):557-567

Division of Enzyme Pathophysiology, Institute for Enzyme Research, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan.

Human D-amino acid oxidase (DAO) is a flavoenzyme that is implicated in neurodegenerative diseases. We investigated the impact of replacement of proline with leucine at Position 219 (P219L) in the active site lid of human DAO on the structural and enzymatic properties, because porcine DAO contains leucine at the corresponding position. The turnover numbers (kcat) of P219L were unchanged, but its Km values decreased compared with wild-type, leading to an increase in the catalytic efficiency (kcat/Km). Moreover, benzoate inhibits P219L with lower Ki value (0.7-0.9 µM) compared with wild-type (1.2-2.0 µM). Crystal structure of P219L in complex with flavin adenine dinucleotide (FAD) and benzoate at 2.25 Å resolution displayed conformational changes of the active site and lid. The distances between the H-bond-forming atoms of arginine 283 and benzoate and the relative position between the aromatic rings of tyrosine 224 and benzoate were changed in the P219L complex. Taken together, the P219L substitution leads to an increase in the catalytic efficiency and binding affinity for substrates/inhibitors due to these structural changes. Furthermore, an acetic acid was located near the adenine ring of FAD in the P219L complex. This study provides new insights into the structure-function relationship of human DAO.
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http://dx.doi.org/10.1093/jb/mvaa083DOI Listing
November 2020

Noise suppression beyond the thermal limit with nanotransistor biosensors.

Sci Rep 2020 07 29;10(1):12678. Epub 2020 Jul 29.

LIMMS-CNRS/IIS, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan.

Transistor biosensors are mass-fabrication-compatible devices of interest for point of care diagnosis as well as molecular interaction studies. While the actual transistor gates in processors reach the sub-10 nm range for optimum integration and power consumption, studies on design rules for the signal-to-noise ratio (S/N) optimization in transistor-based biosensors have been so far restricted to 1 µm device gate area, a range where the discrete nature of the defects can be neglected. In this study, which combines experiments and theoretical analysis at both numerical and analytical levels, we extend such investigation to the nanometer range and highlight the effect of doping type as well as the noise suppression opportunities offered at this scale. In particular, we show that, when a single trap is active near the conductive channel, the noise can be suppressed even beyond the thermal limit by monitoring the trap occupancy probability in an approach analog to the stochastic resonance effect used in biological systems.
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http://dx.doi.org/10.1038/s41598-020-69493-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7391715PMC
July 2020

Quantitative analysis of HER2 mRNA expression by RNA in situ hybridization in canine mammary gland tumors: Comparison with immunohistochemistry analysis.

PLoS One 2020 14;15(2):e0229031. Epub 2020 Feb 14.

Department of Veterinary Pathology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.

Spontaneously occurring canine mammary gland tumors share many features with human breast cancer, including biological behavior and histologic features. Compared to transgenic murine model, canine models have advantages including naturally occurring models of human diseases and cancer. In humans, breast cancer is divided into molecular subtypes based on ER, PR, and HER2 expression. In contrast with humans, few studies have evaluated these subtypes in canine mammary gland tumors, including expression of HER2. HER2 expression in canine mammary tissues has been further complicated by controversy regarding the antibody's specificity. This study aimed to investigate c-erbB2 mRNA expression in retrospective formalin-fixed paraffin embedded samples, using RNA in situ hybridization with a novel quantitative assay and to compare this method with immunohistochemistry. Using 48 canine mammary tumor samples and 14 non-neoplastic canine mammary tissues, RNA in situ hybridization was performed with RNAscope® using a canine-specific target gene probe (ERBB2), and quantitative measurement was performed using the housekeeping gene (POLR2A) to calculate the target gene/housekeeping gene ratio. The ratio of ERBB2/POLR2A was quantified using open-source image analysis programs and compared with the immunohistochemistry results. A significant correlation was observed between the HER2 immunohistochemistry score and ERBB2/POLR2A RNA in situ hybridization (P < 0.001). When the HER2 immunohistochemistry score was 3+, significantly higher expression of HER2 mRNA was observed by RNA in situ hybridization. Interestingly, HER2 mRNA was also observed in non-neoplastic mammary tissues by RNA in situ hybridization. This assay potentially facilitates the reliable quantification of mRNA expression levels in retrospective formalin-fixed paraffin-embedded samples. Further studies are required to elucidate the role of HER2 in canine mammary gland tumors and to implement clinical trials in dogs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229031PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7021316PMC
May 2020

Sequential Cell-Processing System by Integrating Hydrodynamic Purification and Dielectrophoretic Trapping for Analyses of Suspended Cancer Cells.

Micromachines (Basel) 2019 Dec 30;11(1). Epub 2019 Dec 30.

Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.

Microfluidic devices employing dielectrophoresis (DEP) have been widely studied and applied in the manipulation and analysis of single cells. However, several pre-processing steps, such as the preparation of purified target samples and buffer exchanges, are necessary to utilize DEP forces for suspended cell samples. In this paper, a sequential cell-processing device, which is composed of pre-processing modules that employ deterministic lateral displacement (DLD) and a single-cell trapping device employing an electroactive microwell array (EMA), is proposed to perform the medium exchange followed by arraying single cells sequentially using DEP. Two original microfluidic devices were efficiently integrated by using the interconnecting substrate containing rubber gaskets that tightly connect the inlet and outlet of each device. Prostate cancer cells (PC3) suspended in phosphate-buffered saline buffer mixed with microbeads were separated and then resuspended into the DEP buffer in the integrated system. Thereafter, purified PC3 cells were trapped in a microwell array by using the positive DEP force. The achieved separation and trapping efficiencies exceeded 94% and 93%, respectively, when using the integrated processing system. This study demonstrates an integrated microfluidic device by processing suspended cell samples, without the requirement of complex preparation steps.
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http://dx.doi.org/10.3390/mi11010047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019789PMC
December 2019

Renal interstitial cell tumor in a dog: clinicopathologic, imaging, and histologic features.

J Vet Diagn Invest 2020 Jan 26;32(1):124-127. Epub 2019 Dec 26.

Small Animal Tumor Diagnostic Center, Department of Veterinary Pathology, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea (Cho, Seung, Kim, Lim, Sur).

Renal interstitial cell tumors are benign tumors of renomedullary origin; however, malignant features have not been reported in dogs, to our knowledge. A 17-y-old spayed female Maltese dog was presented to a local animal hospital with a mass in the right abdomen. Clinicopathologic findings prior to surgery revealed renal insufficiency and anemia. Imaging revealed that the right kidney was enlarged by an amorphous mass with opaque areas, indicative of mineralization. Upon histologic examination, the mass was comprised of malignant mesenchymal cells that produced mucinous matrix. The tumor cells were positive for vimentin and COX-2, but negative for pancytokeratin; the matrix stained positively with alcian blue. Therefore, the mass was diagnosed as a renal interstitial cell tumor, with malignant features. COX-2 may be useful in the diagnosis of canine renal interstitial cell tumors, similar to its diagnostic role in humans.
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http://dx.doi.org/10.1177/1040638719897585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7003225PMC
January 2020

On-chip immunofluorescence analysis of single cervical cells using an electroactive microwell array with barrier for cervical screening.

Biomicrofluidics 2019 Jul 30;13(4):044107. Epub 2019 Jul 30.

Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan.

Several specific tests for cervical screening have been developed recently, including p16/Ki67 dual immunostaining for diagnosing high-risk human papillomavirus positive squamous intraepithelial lesion in the cervix. However, manual screening of cells in an entire glass slide is currently a standard clinical procedure for quantification and interpretation of immunocytochemical features of the cells. Here, we developed a microfluidic device containing an electroactive microwell array with barriers (EMAB) for highly efficient single-cell trapping followed by on-chip immunofluorescence analysis with minimum loss of the sample. EMAB utilizes patterned electrodes at the bottom of cell-sized microwells to trap single cells using dielectrophoresis (DEP) and cell-holding structures behind the microwells to stabilize the position of trapped cells even without DEP. Using the device, we evaluated the performance of p16/Ki67 dual immunostaining of HeLa cells on the chip. The device shows 98% cell-trapping efficiency as well as 92% cell-holding efficiency against the fixed HeLa cells, and we successfully demonstrated high-efficiency on-chip immunofluorescence analysis with minimal loss of sample. p16/Ki67 dual immunostaining using EMAB may be useful for complementary tests for cervical screening in confirming the histopathological diagnosis.
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http://dx.doi.org/10.1063/1.5089796DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6697034PMC
July 2019

Blood lead level and infection in a healthy population: A cross-sectional study.

Arch Environ Occup Health 2020 20;75(6):333-338. Epub 2019 Aug 20.

Department of Occupational and Environmental Medicine, Chonnam National University Hwasun Hospital, Hwasun, Republic of Korea.

The aim of this study was to investigate whether elevated blood lead level (BLL) is a risk factor for infection. Upper gastrointestinal endoscopy was performed on 2,625 subjects who visited a university hospital for general health examination. infection was detected using histologic examination with Giemsa staining, and BLLs were measured. The mean BLL was 2.83 ± 1.31 μg/dL. The prevalence of infection was 27.8%. The BLL was significantly higher in the infection-positive group compared to the non-infected group (2.96 ± 1.33 μg/dL vs. 2.78 ± 1.30 μg/dL,  < 0.001), which remained significant after adjusting for other confounders. infection significantly increased as the BLL increased (OR: 1.143, 95% CI 1.068-1.223). We found a relationship between BLL elevation and infection rate.
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http://dx.doi.org/10.1080/19338244.2019.1654969DOI Listing
August 2020

Classification, bacteriological findings, and analysis of sex hormone receptors and cytokine expression in mammary lesions of abattoir sows.

J Vet Sci 2019 Mar 15;20(2):e11. Epub 2019 Mar 15.

Department of Veterinary Pathology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.

Mammary lesions in sows can prevent suckling piglets from consuming colostrum that provides fundamental nutrients and protective immunity. Although mammary gross lesions are frequently found in sows at farms or slaughterhouses, with the exception of mastitis, they have received little research attention. In this study, we investigated mammary lesions observed in South Korean sows between 2015 and 2016. Mammary tissue samples of 82 sows showing gross lesions during meat inspection were histologically classified and immunohistochemical analysis was conducted to assess the expression of estrogen receptor (ER)-α, ER-β, and progesterone receptor (PR) for mammary hyperplastic lesions as well as that of cluster of differentiation (CD) 3, CD79a, interleukin (IL)-1α, IL-1β, IL-6, and IL-8 for mastitis. Furthermore, 20 swab samples were cultured, and the isolated bacteria were identified using polymerase chain reactions for 16S ribosomal RNA genes. The lesions were classified as hyperplasia, mastitis, or hyperplasia with mastitis. Immunohistochemistry results revealed that there was neither expression of ER-α nor of ER-β, but all examined hyperplastic samples expressed PR. In addition, there was a significant correlation between CD3 and IL-1β expressions, as well as between IL-1β and IL-6 expressions. Regarding the identity of the isolated bacteria, spp. were most frequently detected. The results of this study have revealed the incidence and characteristics of porcine mammary lesions.
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http://dx.doi.org/10.4142/jvs.2019.20.e11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6441806PMC
March 2019

Age- and gender-dependent D-amino acid oxidase activity in mouse brain and peripheral tissues: implication for aging and neurodegeneration.

J Biochem 2019 Aug;166(2):187-196

Division of Enzyme Pathophysiology, Institute for Enzyme Research, Tokushima University, 3-18-15 Kuramoto, Tokushima, Japan.

D-amino acid oxidase (DAO) is a flavoenzyme, catalysing oxidative deamination of D-amino acids to produce corresponding α-keto acids, ammonia and hydrogen peroxide. In our search for DAO activity among various tissues, we developed a sensitive assay based on hydrogen peroxide production involving enzyme-coupled colorimetric assay with peroxidase. We first optimized buffer components to extract DAO protein from mouse tissues. Here we show that DAO activity was detected in kidney, cerebellum, medulla oblongata, midbrain and spinal cord, but not in liver. In addition, we observed that DAO activity and expression were decreased in thoracic and lumbar regions of spinal cord in aged mice when compared with young mice, indicating that decreased DAO is involved in motoneuron degeneration during senescence. We also found gender difference in DAO activity in the kidney, suggesting that DAO activity is influenced by sexual dimorphism. We newly detected DAO activity in the epididymis, although undetected in testis. Furthermore, DAO activity was significantly higher in the caput region than corpus and cauda regions of epididymis, indicating that D-amino acids present in the testis are eliminated in epididymis. Taken together, age- and gender-dependent DAO activity in each organ may underlie the human pathophysiology regulated by D-amino acid metabolism.
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http://dx.doi.org/10.1093/jb/mvz025DOI Listing
August 2019

Evaluation of the prevalence of musculoskeletal symptoms, presumptive diagnosis, medical care use, and sick leave among female school meal service workers.

Ann Occup Environ Med 2019 15;31. Epub 2019 Jan 15.

1Department of Occupational and Environmental Medicine, Chosun University Hospital, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Background: Most of the school meal service workers in Korea are middle-aged individuals. They have high workload, which increases their incidence of musculoskeletal disorders. This study aimed to evaluate the prevalence and risk factors of subjective musculoskeletal symptoms, presumptive diagnosis, medical care use, and sick leave among female school meal workers.

Methods: We analyzed the results of musculoskeletal disease screening of 1581 female school meal workers. The screening consisted of self-administered questionnaire, history taking by occupational physicians, and physical examination. The prevalence of subjective musculoskeletal symptoms, presumptive diagnosis after initial examination by occupational physicians, use of medical care for more than 7 days, and sick leave due to musculoskeletal diseases during the past year were evaluated in this study. The relative risk of four outcome indicators of musculoskeletal disorders was compared with respect to potential factors, such as age, subjective physical loading, present illness, injury experience, and type of school, using log-binomial regression.

Results: The prevalence of subjective musculoskeletal symptom was 79.6%; presumptive diagnosis, 47.6%; hospital visits over 7 days, 36.4%; and sick leave, 7.3%. The relative risk of musculoskeletal symptoms by age (≥50 years vs < 50 years) was 1.04 (95% confidence interval (CI): 1.00-1.09); presumptive diagnosis of musculoskeletal disease, 1.17 (95% CI: 1.06-1.30); hospital visits over 7 days, 1.26 (95% CI: 0.85-1.85); and sick leave, 1.17 (95% CI: 1.02-1.34). The relative risk of musculoskeletal symptoms due to subjective physical loading (very hard vs low) was 1.45 (95% CI: 1.33-1.58); presumptive diagnosis, 2.92 (95% CI: 2.25); hospital visits over 7 days, 1.91 (95% CI: 1.02-3.59); and sick leave, 2.11 (95% CI: 1.63-2.74).

Conclusions: Subjective physical loading was a more important factor in musculoskeletal disorders than the age of female school meal workers.
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http://dx.doi.org/10.1186/s40557-019-0281-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6334380PMC
January 2019

Cancer marker-free enrichment and direct mutation detection in rare cancer cells by combining multi-property isolation and microfluidic concentration.

Lab Chip 2019 02;19(5):757-766

Institute of Industrial Science, The University of Tokyo, Tokyo, Japan.

Genetic analysis, rather than simply counting the number of circulating tumor cells (CTCs), which are rare cancer cells in peripheral blood, has great potential for non-invasive biopsy or "liquid biopsy." However, a practical problem in conventional enrichment of CTCs is that the isolated target cells are mixed with numerous residual leukocytes, and are suspended in a large volume. Hence, further isolation (i.e., cytokeratin (CK)-positive cell picking) or DNA purification is required for downstream genetic analysis after isolation. Here, we propose a novel cancer marker-free method of CTC enrichment by size-based Filtration and Immunomagnetic Negative selection followed by Dielectrophoretic concentration (CTC-FIND) for direct detection of genetic mutations in rare cancer cells suspended in whole blood. A combination of two independent isolation methods based on physical (filtration) and biochemical properties (immunomagnetic negative selection) in CTC-FIND allowed highly efficient cancer marker-free purification (5.1-log depletion of leukocytes). The isolated cells were trapped and concentrated using a microfluidic step-channel device using dielectrophoresis for discrimination and downstream genetic analysis. The feasibility of cancer marker-free enrichment by CTC-FIND was successfully demonstrated by directly detecting mutations in various cancer cells with a very high sensitivity of 1 cell per mL, including EpCAM and CK-negative cells, which were used to spike 8 mL of whole blood. Thus, CTC-FIND can be used with liquid biopsy to detect genetic mutations in wide-ranging CTC subsets, independent of cancer cell-specific marker expression.
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http://dx.doi.org/10.1039/c8lc00772aDOI Listing
February 2019

Increased p63 Expression in Canine Perianal Gland Tumours.

J Vet Res 2018 Jun 24;62(2):229-235. Epub 2018 Oct 24.

Small Animal Tumour Diagnostic Centre, Department of Veterinary Pathology, Konkuk University, 05029, Seoul, Republic of Korea.

Introduction: p63 is a homologous molecule of p53 and was recently identified as playing important roles in several key cellular processes, including epithelial development and proliferation. Since then, several studies have demonstrated altered p63 expression in various cancers of epithelial origin. Canine perianal gland tumour is one of the most common skin neoplasms in dogs; however, the molecular characteristics of this tumour remain poorly understood. The objective of the present study was to analyse and compare the expression of p63 in canine perianal gland adenomas and carcinomas.

Material And Methods: Haematoxylin and eosin-stained slides were examined and immunohistochemistry was conducted for a total of 65 samples. Immunohistochemical data for p63 expressions were compared between groups using the Mann-Whitney U test.

Results: The p63 expression level was increased in perianal gland carcinomas compared to that in the adenoma samples (P < 0.0001). The percentage of cells expressing p63 was higher in perianal gland carcinomas than in adenomas, although the intensity of immunostaining did not differ significantly between the two groups.

Conclusion: p63 is a candidate factor contributing to the malignant transformation and progression of canine perianal gland tumours.
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http://dx.doi.org/10.2478/jvetres-2018-0020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6200288PMC
June 2018

Ferroelectric-mediated filamentary resistive switching in P(VDF-TrFE)/ZnO nanocomposite films.

Phys Chem Chem Phys 2018 Jun;20(23):16176-16183

School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Oryong-Dong, Buk-Gu, Gwangju 61005, South Korea.

In ferroelectric (FE) polymer-semiconducting polymer blend based organic resistive random access memory devices (ReRAM), the carriers are injected into the semiconductor region of the blend because of the polarization originated internal electric field in the FE polymer. A higher concentration of semiconducting polymer in the FE polymer-semiconducting polymer blends usually generate a high leakage current and degrades the FE characteristics of the FE polymer resulting in a high OFF current and consequently a low ON/OFF ratio. In order to achieve a high ON/OFF ratio in the FE polymer/semiconducting polymer blends, the FE properties of the FE polymer should be preserved. In this study, organic ReRAMs based on ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) and ZnO nanoparticle (NPs) blends exhibiting bipolar resistive switching and a high ON/OFF ratio were realized using a low-cost solution process. Unlike conventional ferroelectric polymer-semiconducting polymer blend systems where FE characteristics are suppressed in ReRAMs, our Au/P(VDF-TrFE)_ZnO NPs/n++Si devices retain the FE characteristics of the P(VDF-TrFE) polymers. Our devices switch between bi-stable resistance states via the ferroelectric-assisted filamentary conduction mechanism. Based on ex situ transmission electron microscopy and elemental mapping analyses, we found that the resistive switching occurs through the formation of conduction paths consisting of Zn-rich/F-deficient regions. The device fabricated at a blend ratio of 20 wt% ZnO NPs in P(VDF-TrFE) matrix exhibited optimal stable resistive switching behavior with an ON/OFF ratio of up to 2 × 107 and a retention time of 104 s.
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http://dx.doi.org/10.1039/c8cp02024hDOI Listing
June 2018

CD204-Expressing Tumor-Associated Macrophages Are Associated With Malignant, High-Grade, and Hormone Receptor-Negative Canine Mammary Gland Tumors.

Vet Pathol 2018 05 17;55(3):417-424. Epub 2018 Jan 17.

1 Department of Veterinary Pathology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University, Gwangjin-gu, Seoul, Republic of Korea.

Tumor-associated macrophages (TAMs) are an important component of leukocyte infiltration in tumors. TAMs can be classified into M1 and M2 phenotypes. In the present study, the expression of CD204, an M2-polarized macrophage receptor, was investigated by immunohistochemistry in the area surrounding TAMs in 101 cases of canine mammary gland tumor (CMT). We examined the relationship between M2-polarized TAMs and malignancy, histological subtype, histological grade, molecular subtype, hormone receptor (HR) status, and clinical obesity indices. The mean number of CD204-positive macrophages was significantly higher in malignant CMTs than in benign CMTs ( P = .000). The number of CD204-positive macrophages differed significantly between histological grades ( P = .000) and were significantly higher in grade III than in grades I and II. Moreover, the mean number of CD204-positive macrophages was significantly higher in HR-negative malignant CMTs than in HR-positive malignant CMTs ( P = .035) and in malignant CMTs with lymphatic invasion compared to malignant CMTs without lymphatic invasion ( P = .000). These findings suggest that CD204-positive macrophages might affect the development and behavior of CMTs and highlight the potential of CD204 as a prognostic factor.
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http://dx.doi.org/10.1177/0300985817750457DOI Listing
May 2018

Novel transparent collagen film patch derived from duck's feet for tympanic membrane perforation.

J Biomater Sci Polym Ed 2018 May - Jun;29(7-9):997-1010. Epub 2017 Sep 7.

a School of Medicine , Nano-Bio Regenerative Medical Institute, Hallym University , Chuncheon , Republic of Korea.

To increase healing rate of tympanic membrane (TM) perforations, patching procedure has been commonly conducted. Biocompatible, biodegradable patching materials which is not limited across cultures is needed. The authors evaluated the effectiveness of novel transparent duck's feet collagen film (DCF) patch in acute traumatic TM perforation. This procedure was compared with spontaneous healing and paper patching. Cell proliferation features were observed in paper and DCF patches. Forty-eight TMs of 24 rats were used for animal experiment, perforations were made on each TMs, and divided into three groups according to treatment modality. Sixteen were spontaneously healed, 16 were paper patched and 16 were DCF patched. The gross and histological healing results were analyzed. Both paper and DCF patch showed no cytotoxicity, but cell proliferations were more active in DCF than paper in early stage. In animal study, the healing of TM perforations were completed within 14 days in all three groups, but found to be faster in DCF patch group than paper patch or spontaneous healing group. The DCF patches were transparent and size of DCF patches were gradually decreased, so there were no need to remove the DCF patches to check the wound status or after the completion of healing. According to this result, authors concluded that DCF patch is transparent, biocompatible and biodegradable material, and can induce fast healing in acute traumatic TM perforations.
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http://dx.doi.org/10.1080/09205063.2017.1374031DOI Listing
June 2019
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