Publications by authors named "Inpyo Hong"

9 Publications

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Diverse patterns of bone regeneration in rabbit calvarial defects depending on the type of collagen membrane.

J Periodontal Implant Sci 2021 Feb;51(1):40-52

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: Various crosslinking methods have been introduced to increase the longevity of collagen membranes. The aim of this study was to compare and evaluate the degradation and bone regeneration patterns of 3 collagen membranes.

Methods: Four 8-mm-diameter circular bone defects were created in the calvaria of 10 rabbits. In each rabbit, each defect was randomly allocated to 1) the sham control group, 2) the non-crosslinked collagen sponge (NS) group, 3) the chemically crosslinked collagen membrane (CCM) group, or 4) the biphasic calcium phosphate (BCP)-supplemented ultraviolet (UV)-crosslinked collagen membrane (UVM) group. Each defect was covered with the allocated membrane without any graft material. Rabbits were sacrificed at either 2 or 8 weeks post-surgery, and radiographic and histologic analyses were done.

Results: New bone formed underneath the membrane in defects in the CCM and UVM groups, with a distinctive new bone formation pattern, while new bone formed from the base of the defect in the NS and control groups. The CCM maintained its shape until 8 weeks, while the UVM and NS were fully degraded at 8 weeks; simultaneously, sustained inflammatory infiltration was found in the margin of the CCM, while it was absent in the UVM. In conclusion, the CCM showed longer longevity than the UVM, but was accompanied by higher levels of inflammation.

Conclusions: Both the CCM and UVM showed distinctive patterns of enhancement in new bone formation in the early phase. UV crosslinking can be a biocompatible alternative to chemical crosslinking.
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http://dx.doi.org/10.5051/jpis.2004180209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7920838PMC
February 2021

Clinical and Microbiological Efficacy of Pyrophosphate Containing Toothpaste: A Double-Blinded Placebo-Controlled Randomized Clinical Trial.

Microorganisms 2020 Nov 17;8(11). Epub 2020 Nov 17.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea.

(1) Background: Dental calculus works as a niche wherein pathogenic bacteria proliferate in the oral cavity. Previous studies revealed the anticalculus activity of pyrophosphates, however there was no clinical study that evaluated microbiome changes associated with calculus inhibition. Therefore, the aim of this randomized clinical trial was to evaluate the calculus inhibition of pyrophosphate-containing toothpaste and its effect on oral microbiome changes. (2) Methods: Eighty subjects with a calculus index ≥2 on the lingual of the mandibular anterior tooth were randomly allocated to the test group that pyrophosphate-containing toothpaste was given to or the placebo control group. Full mouth debridement and standardized tooth brushing instruction were given before the allocation. Plaque index, gingival index, calculus index, probing depth, and bleeding on probing were measured at the baseline, and at 4, 8 and 12 weeks. Genomic DNA was extracted from the plaque samples collected at the baseline and at 12 weeks, and 16S ribosomal RNA gene amplicon sequencing was applied for microbiome analysis. (3) Results: None of the clinical parameters showed significant differences by visits or groups, except the plaque index of the test group, which reduced significantly between 4 and 12 weeks. A significant difference of microbiome between the baseline and 12 weeks was observed in the test group. Between baseline and 12 weeks, the proportion of decreased in the control group, and the proportions of , and in the phylum level and the proportions of , and in the genus level decreased in the test group. In the test group, as plaque index decreased, increased, and and decreased. (4) Conclusion: The use of pyrophosphate-containing toothpaste effectively inhibited the dysbiosis of the oral microbiome and the proliferation of pathogenic species in periodontal disease. Clinically, plaque formation in the pyrophosphate-containing toothpaste group was effectively decreased, however there was no significant change in calculus deposition.
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http://dx.doi.org/10.3390/microorganisms8111806DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7698517PMC
November 2020

Oral Fluid Biomarkers for Diagnosing Gingivitis in Human: A Cross-Sectional Study.

J Clin Med 2020 Jun 3;9(6). Epub 2020 Jun 3.

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul 120-749, Korea.

Diagnoses based on oral fluid biomarkers have been introduced to overcome limitations of periodontal probe-based diagnoses. Diagnostic ability of certain biomarkers for periodontitis have been identified and widely studied, however, such studies targeting gingivitis is scarce. The aims of this study were to determine and compare the efficacies and accuracies of eight biomarkers in diagnosing gingivitis with the aid of receiver operating characteristic (ROC) curves. The probing depth (PD), clinical attachment loss (CAL), bleeding on probing (BOP), gingival index (GI), and plaque index (PI) were examined in 100 participants. Gingival crevicular fluid was collected using paper points, and whole-saliva samples were collected using cotton roll. Samples were analyzed using enzyme-linked immunosorbent assay kits for the different biomarkers. The levels of matrix metalloproteinase (MMP)-8, MMP-9, lactoferrin, cystatin C, myeloperoxidase (MPO), platelet-activating factor, cathepsin B, and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen were analyzed. MPO and MMP-8 levels in saliva were strongly correlated with gingivitis, with Pearson's correlation coefficients of 0.399 and 0.217, respectively. The area under the curve (AUC) was largest for MMP-8, at 0.814, followed by values of 0.793 and 0.777 for MPO and MMP-9, respectively. The clinical parameters of GI and PI showed strong correlations and large AUC values, whereas PD and CAL did not. MMP-8 and MPO were found to be effective for diagnosing gingivitis. Further investigations based on the results of this study may identify clinically useful biomarkers for the accurate and early detection of gingivitis.
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http://dx.doi.org/10.3390/jcm9061720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356847PMC
June 2020

Distinctive bone regeneration of calvarial defects using biphasic calcium phosphate supplemented ultraviolet-crosslinked collagen membrane.

J Periodontal Implant Sci 2020 Feb 19;50(1):14-27. Epub 2019 Dec 19.

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: To overcome several drawbacks of chemically-crosslinked collagen membranes, modification processes such as ultraviolet (UV) crosslinking and the addition of biphasic calcium phosphate (BCP) to collagen membranes have been introduced. This study evaluated the efficacy and biocompatibility of BCP-supplemented UV-crosslinked collagen membrane for guided bone regeneration (GBR) in a rabbit calvarial model.

Methods: Four circular bone defects (diameter, 8 mm) were created in the calvarium of 10 rabbits. Each defect was randomly allocated to one of the following groups: 1) the sham control group (spontaneous healing); 2) the M group (defect coverage with a BCP-supplemented UV-crosslinked collagen membrane and no graft material); 3) the BG (defects filled with BCP particles without membrane coverage); and 4) the BG+M group (defects filled with BCP particles and covered with a BCP-supplemented UV-crosslinked collagen membrane in a conventional GBR procedure). At 2 and 8 weeks, rabbits were sacrificed, and experimental defects were investigated histologically and by micro-computed tomography (micro-CT).

Results: In both micro-CT and histometric analyses, the BG and BG+M groups at both 2 and 8 weeks showed significantly higher new bone formation than the control group. On micro-CT, the new bone volume of the BG+M group (48.39±5.47 mm) was larger than that of the BG group (38.71±2.24 mm, =0.032) at 8 weeks. Histologically, greater new bone area was observed in the BG+M group than in the BG or M groups. BCP-supplemented UV-crosslinked collagen membrane did not cause an abnormal cellular reaction and was stable until 8 weeks.

Conclusions: Enhanced new bone formation in GBR can be achieved by simultaneously using bone graft material and a BCP-supplemented UV-crosslinked collagen membrane, which showed high biocompatibility and resistance to degradation, making it a biocompatible alternative to chemically-crosslinked collagen membranes.
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http://dx.doi.org/10.5051/jpis.2020.50.1.14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040443PMC
February 2020

Isolation of Abscisic Acid from Korean Acacia Honey with Anti- Activity.

Pharmacogn Mag 2017 Jul 11;13(Suppl 2):S170-S173. Epub 2017 Jul 11.

Department of Agricultural Biology, National Institute of Agricultural Science, Wanju, Korea.

Background: () is linked to the development of the majority of peptic ulcers and some types of gastric cancers, and its antibiotic resistance is currently found worldwide.

Objective: This study is aimed at evaluating the anti- activity of Korean acacia honey and isolating the related active components using organic solvents.

Material And Methods: The crude acacia honey was extracted with -hexane, dichloromethane, ethyl acetate (EtOAc), and -butanol. The EtOAc extract was subjected to octadecyl-silica chromatography. The extracts and fractions were then examined for anti- activity using the agar well diffusion method. The antimicrobial activity of abscisic acid against was investigated by determining the minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), and by performing a time-kill assay.

Results: Abscisic acid related to the botanical origins of acacia honey from Korea has been analyzed using ultra-performance liquid chromatography. The MICs and MBCs of abscisic acid were 2.7 ± 1.3 and 6.9 ± 1.9 μg/mL, respectively. The bactericidal activity of abscisic acid (at 10.8 μg/mL corresponding to 4 × MIC) killed the organism within 36-72 h. These results suggest that abscisic acid isolated from Korean acacia honey has antibacterial activity against .

Conclusion: Abscisic acid isolated from Korean acacia honey can be therapeutic and may be further exploited as a potential lead candidate for the development of treatments for -induced infections.

Summary: The crude acacia honey was extracted with -hexane, dichloromethane, EtOAc, and -butanolThe EtOAc extract yielded eight fractions and four subfractions were subsequently obtained chromatographicallyAbscisic acid was isolated from one subfractionAll the solvent extracts and fractions showed antibacterial activity against Abscisic acid exhibited antibacterial activity against . MeOH: Methanol; EtOAc: Ethyl acetate; TSB: Trypticase soy broth; MIC: Minimum inhibitory concentration; MBC: Minimum bactericidal concentration; CFU: Colony-forming units; UPLC: Ultra-performance liquid chromatography; DAD: Diode array detector; UV: Ultraviolet; ODS: Octadecyl-silica; MS: Mass spectrometry; SE: Standard error.
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http://dx.doi.org/10.4103/0973-1296.210166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5538150PMC
July 2017

Effects of graphene oxides on soil enzyme activity and microbial biomass.

Sci Total Environ 2015 May 7;514:307-13. Epub 2015 Feb 7.

Department of Materials Science and Engineering, Korea University, Seoul 136-713, Republic of Korea.

Due to recent developments in nanotechnology, nanomaterials (NMs) such as graphene oxide (GO) may enter the soil environment with mostly unknown consequences. We investigated the effects of GO on soil microbial activity in a 59-day soil incubation study. For this, high-purity GO was prepared and characterized. Soils were treated with up to 1 mg GO g(-1) soil, and the changes in the activities of 1,4-β-glucosidase, cellobiohydrolase, xylosidase, 1,4-β-N-acetyl glucosaminidase, and phosphatase and microbial biomass were determined. 0.5-1 mg GO g(-1) soil lowered the activity of xylosidase, 1,4-β-N-acetyl glucosaminidase, and phosphatase by up to 50% when compared to that in the control soils up to 21 days of incubation. Microbial biomass in soils treated with GO was not significantly different from that in control soils throughout the incubation period, and the soil enzyme activity and microbial biomass were not significantly correlated in this study. Our results indicate that soil enzyme activity can be lowered by the entry of GO into soils in short term but it can be recovered afterwards.
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http://dx.doi.org/10.1016/j.scitotenv.2015.01.077DOI Listing
May 2015

Insight into the 6-thiopurine-mediated termination of the invasive motility of tumor cells derived from inflammatory breast cancer.

Biochemistry 2011 Jun 2;50(25):5731-42. Epub 2011 Jun 2.

Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, USA.

Our study showed that a combination of 6-thiopurine (6-TP) drugs and a redox agent effectively inhibits the motility of SUM cells derived from human inflammatory breast cancer (IBC) cells and RhoC-overexpressed mammary epithelium cells. This 6-TP-mediated inhibition of cell motility occurs because the treated 6-TPs target and inactivate RhoC. A molecular mechanism for inactivation by the 6-TP-mediated RhoC is proposed by which treated TPs are converted in cells into 6-thioguanosine phosphate (6-TGNP). This 6-TGNP in turn reacts with the Cys(20) side chain of the redox-sensitive GXXXCGK(S/T)C motif of RhoC to produce a 6-TGNP-RhoC disulfide adduct. A redox agent synergistically enhances the formation process of this disulfide. The adduct that is formed impedes RhoC guanine nucleotide exchange, which populates an inactive RhoC. Our results suggest that 6-TGNP can also react with the redox-sensitive GXXXCGK(S/T)C and GXXXXGK(S/T)C motif of RhoA and Rac, respectively, to produce a 6-TGNP-RhoA and 6-TGNP-Rac disulfide adduct. However, given that RhoC has been shown to be overexpressed in ∼90% of IBC lesions, the populated RhoC but not other Rho proteins is likely to be a primary target for 6-TPs and a redox agent to terminate the metastasis of IBC.
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http://dx.doi.org/10.1021/bi200347yDOI Listing
June 2011

Ras-targeting action of thiopurines in the presence of reactive nitrogen species.

Biochemistry 2010 May;49(18):3965-76

Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, USA.

Thiopurine drugs are commonly used in the treatment of certain cancers, autoimmune disorders, organ transplant rejection, and bowel disease. Because long-term treatment with thiopurines for certain diseases is common, the cytotoxic effects associated with chronic exposure to thiopurine drugs are inevitable. The results shown in this study indicate that the oncogenic Ras in model cancer cell lines forms a complex with thioguanine nucleotide that is derived from long-term treatment with thiopurines. This study also showed that the Ras thioguanine nucleotide binary complex is likely to be a direct target of a redox agent, resulting in downregulation of the oncogenic Ras. This study proposes a radical-based molecular mechanism for the path of Ras-targeting thiopurines used in conjunction with redox agents. Given that Ras plays a central role in cellular signaling pathways, any interference with Ras activity by thiopurines and redox agents has the potential for devastating cytotoxic effects.
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http://dx.doi.org/10.1021/bi902090qDOI Listing
May 2010

Simple purification of human antimicrobial peptide dermcidin (MDCD-1L) by intein-mediated expression in E.coli.

J Microbiol Biotechnol 2010 Feb;20(2):350-5

Department of Bioengineering and Technology, Kangwon National University, Chuncheon 200-701, Korea.

Among human antimicrobial peptides (hAMPs), DCD-1L has a broad spectrum of antimicrobial activity over a wide pH range and in high salt concentrations. It offers a promising alternative to conventional antibiotics. The 458-bp-long dermcidin cDNA was amplified by PCR using a human fetal cDNA library as a template. The 147-bp fragment of the MDCD-1L gene encoding an additional methionine residue was subcloned into the pTYB11 vector. Recombinant MDCD-1L was expressed as an intein fusion protein in E. coli, and then purified by affinity chromatography using chitin beads. A small peptide with a molecular mass of about 5 kDa was detected by tricine gel electrophoresis. The recombinant MDCD-1L peptide was purified from the gel and its amino acid sequence was determined by nanoLC-ESI-MS/MS analysis. The initiating amino acid, methionine, remained attached to the N-terminal region of recombinant MDCD-1L. Purified MDCD-1L showed antimicrobial activity against a Micrococcus luteus test strain.
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February 2010