In vitro and in vivo anti-pigmentation effects of 2-mercaptobenzimidazoles as nanomolar tyrosinase inhibitors on mammalian cells and zebrafish embryos: Preparation of pigment-free zebrafish embryos

Recently, 10 2-mercaptobenzo[d]imidazole (2-MBI) compounds (1-10) were synthesized. Although all 2-MBI compounds are tyrosinase inhibitors that inhibit mushroom tyrosinase at extremely low concentrations (IC50 values: 20-740 nM) and effectively inhibit the browning of apples, to our knowledge, no studies have determined whether 2-MBI compounds inhibit mammalian tyrosinase. Mammalian tyrosinase is different from mushroom tyrosinase in its distribution within the cell and has structural characteristics that are different from mushroom tyrosinase in amino acid sequence and in the presence of a quaternary structure. Thus, the effect of the 10 2-MBI compounds on mammalian tyrosinase activity was investigated in B16F10 cells. Six compounds (1-6) exhibited stronger intracellular tyrosinase inhibition than that of kojic acid and phenylthiourea (PTU), which are known to be the most potent tyrosinase inhibitors; their strong tyrosinase inhibitory activity robustly inhibited intracellular melanin production in B16F10 cells. None of the tested 2-MBI compounds exhibited appreciable cytotoxicity in HaCaT and B16F10 cells. To confirm the anti-melanogenic efficacy of the 2-MBI compounds in vivo, a zebrafish embryo model was used. At concentrations 100 times lower than kojic acid, most 2-MBI compounds demonstrated much stronger depigmentation efficacy than that of kojic acid, and three 2-MBI compounds (2-4) showed depigmentation activity similar to or more potent than that of PTU, resulting in nearly pigment-free zebrafish embryos. These results suggest that 2-MBI compounds may be potential therapeutic agents for hyperpigmentation-related disorders.

Thiazol-4(5H)-one analogs as potent tyrosinase inhibitors: Synthesis, tyrosinase inhibition, antimelanogenic effect, antioxidant activity, and in silico docking simulation

As the β-phenyl-α,β-unsaturated carbonyl (PUSC) structure was previously identified to play a key role in tyrosinase inhibition, 14 analogs with a PUSC structure built on a thiazol-4(5H)-one scaffold were synthesized using Knoevenagel condensation to serve as potential tyrosinase inhibitors. Through mushroom tyrosinase inhibition experiments, two analogs 9 and 11 were identified as potent tyrosinase inhibitors, with 11 exhibiting an IC50 value of 0.4 ± 0.01 μM, which indicates its 26-fold greater potency than kojic acid. Kinetic studies using Lineweaver-Burk plots revealed that 9 and 11 are competitive and mixed-type inhibitors, respectively; these kinetic results were supported by docking simulations. According to the B16F10 cell-based experiments, 9 and 11 inhibited melanogenesis more effectively than kojic acid due to their potent cellular tyrosinase inhibitory activity. In addition, analogs 9 and 11 exhibited moderate-to-strong antioxidant capacity, scavenging ABTS+, DPPH, and ROS radicals. In particular, analog 12 with a catechol moiety exhibited very strong ROS-scavenging activity, similar to Trolox. These results suggest that analogs 9 and 11, which exhibit potent tyrosinase inhibitory activity in mushroom and mammalian cells and anti-melanogenic effects in B16F10 cells, are promising antibrowning agents for crops and skin lightening agents for hyperpigmentation-related diseases.

MHY446 induces apoptosis via reactive oxygen species-mediated endoplasmic reticulum stress in HCT116 human colorectal cancer cells

This study investigated the potential of a newly synthesized histone deacetylase (HDAC) inhibitor, MHY446, in inducing cell death in HCT116 colorectal cancer cells and compared its activity with that of suberoylanilide hydroxamic acid (SAHA), a well-known HDAC inhibitor. The results showed that MHY446 increased the acetylation of histones H3 and H4 and decreased the expression and activity of HDAC proteins in HCT116 cells. Additionally, MHY446 was confirmed to bind more strongly to HDAC1 than HDAC2 and inhibit its activity. In vivo experiments using nude mice revealed that MHY446 was as effective as SAHA in inhibiting HCT116 cell-grafted tumor growth. This study also evaluated the biological effects of MHY446 on cell survival and death pathways. The reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) confirmed that ROS play a role in MHY446-induced cell death by reducing poly(ADP-ribose) polymerase cleavage. MHY446 also induced cell death via endoplasmic reticulum (ER) stress by increasing the expression of ER stress-related proteins. NAC treatment decreased the expression of ER stress-related proteins, indicating that ROS mediate ER stress as an upstream signaling pathway and induce cell death. While MHY446 did not exhibit superior HDAC inhibition efficacy compared to SAHA, it is anticipated to provide innovative insights into the future development of therapeutic agents for human CRC by offering novel chemical structure-activity relationship-related information.

Identification and molecular mechanism of novel 5-alkenyl-2-benzylaminothiazol-4(5H)-one analogs as anti-melanogenic and antioxidant agents

Mushroom tyrosinase is a tetramer, whereas mammalian tyrosinase is a monomeric glycoprotein. In addition, the amino acid sequence of mushroom tyrosinases differs from that of mammalian tyrosinases. MHY2081 exhibits potent inhibitory activity against both mushroom and mammalian tyrosinases. Accordingly, based on the MHY2081 structure, 5-alkenyl-2-benzylaminothiazol-4(5H)-one analogs were designed as a novel anti-tyrosinase agent and synthesized using 2-((3,4-dimethoxybenzyl)amino)thiazol-4(5H)-one (16), a key intermediate obtained via the rearrangement of a benzylamino group. Compounds 6 and 9 (IC50 = 1.5-4.6 µM) exhibited higher mushroom tyrosinase inhibitory activity than kojic acid (IC50 = 20-21 µM) in the presence of l-tyrosine and/or l-dopa. Based on kinetic analysis using Lineweaver-Burk plots, 6 was a mixed inhibitor, whereas 9 was a competitive inhibitor, and docking simulation results supported that these compounds could bind to the active site of mushroom tyrosinase. Using B16F10 mammalian cells, we demonstrated that these compounds inhibited melanogenesis more potently than kojic acid, and their anti-melanogenic effects could be attributed to tyrosinase inhibition. All synthesized compounds could scavenge reactive oxygen species (ROS), with five compounds exhibiting mild-to-strong ABTS+ and DPPH radical-scavenging abilities. Compounds 6 and 9 were potent tyrosinase inhibitors with strong antioxidant activities against ROS, ABTS+, and DPPH radicals. Moreover, the compounds significantly suppressed tyrosinase expression in a dose-dependent manner. Collectively, these results suggest that the novel 5-alkenyl-2-benzylaminothiazol-4(5H)-one analogs, especially 6 and 9, are potential anti-melanogenic agents with antioxidant activity.

U-shaped associations between glycated albumin and obesity and role of IL-10 in hyperacute ischemic stroke

OBJECTIVE

There is growing interest in the use of new biomarkers such as glycated albumin (GA). In contrast to glycated hemoglobin (HbA1c), GA showed an inverse correlation with prestroke obesity status, but data are limited for ischemic stroke (IS).

MATERIALS AND METHODS

We explored the association between GA and body mass index (BMI) and investigated inflammatory cytokines to support the academic background. In total, 155 patients with hyperacute IS (HIS) between 2011 and 2019 were included. To identify the association between GA and BMI, patients were divided into four groups according to BMI quartiles. Levels of inflammatory cytokines, including IL-1β, IL-10, IL-6, TNF-α, and TNF-R1, were determined by ELISA using a ProcartaPlex multiplex immunoassay.

RESULTS

The mean age of the 155 patients was 68 ± 12 years, and 67.1% were men. The lowest BMI group had higher GA levels (GA 2 T and 3 T = 80%) (p-value=0.017), and these U-shaped associations were maintained only for small vessel occlusion etiology (p-value= 0.004). Plasma IL-10 levels were positively correlated with BMI and showed a U-shaped pattern (p-value= 0.001).

CONCLUSION

GA levels and BMI had U-shaped associations with HIS. IL-10, which acts as a protective cytokine for cardiovascular disease, may play a novel role in this association. Although GA is an emerging favorable clinical marker of cardiovascular outcomes, obesity status should be considered when interpreting these associations.

Definitive Radiotherapy in Patients with Clinical T1N0M0 Esophageal Squamous Cell Carcinoma: A Multicenter Retrospective Study

PURPOSE/OBJECTIVE(S)

In this study, we aimed to assess the failure pattern and survival outcomes and to analyze the optimal treatment field of definitive RT for T1N0M0 esophageal squamous cell carcinoma (ESCC).

MATERIALS/METHODS

We performed a retrospective analysis in a multi-institutional cohort of patients with histologically confirmed T1N0M0 ESCC. We included patients who underwent RT with definitive aim from 2010 to 2019. Patterns of failure were demonstrated as in-field locoregional, out-field locoregional and distant metastasis. In the survival analysis, freedom from locoregional recurrence and their association with clinicopathologic risk factors were analyzed. We performed a propensity score matching in the cT1b patients to adjust for the heterogeneity of radiation technique, radiation dose and the use of concurrent chemotherapy.

RESULTS

A total of 168 patients were included with a median follow-up of 34.0 months, and there were 20 cT1a, 94 cT1b and 24 cT1x, (cT1, not otherwise specified) patients. The rates of all and locoregional failure were 26.9% and 23.1% for cT1a and 25.0% and 22.4% for cT1b patients. 10 (10.6%) patients experienced grade ≥ 3 adverse events. Among 116 cT1b patients, 69 patients received elective nodal irradiation (ENI) and 47 patients received involved field irradiation (IFI). After propensity score matching, the 3-year FFLRR rate was 84.5% (95% Confidence Interval, 71.0 - 92.1%). There was no significant difference between the ENI and IFI patients in FFLRR (Log-rank P = 0.831). In the multivariate analysis, the use of concurrent chemotherapy was the only factor marginally associated with FFLRR (Hazard ratio, 0.17; 95% CI, 0.02 - 1.13; P = 0.067).

CONCLUSION

cT1a patients who cannot receive endoscopic resection, showed similar rates of failure compared with cT1b patients, which questioned the accuracy of the staging and raised the need for through treatment such as chemoradiotherapy. In cT1b patients, IFI using dose of 50 to 60 Gy with concurrent chemotherapy could be a reasonable treatment option.

Anti-Browning Effect of 2-Mercaptobenzo[d]imidazole Analogs with Antioxidant Activity on Freshly-Cut Apple Slices and Their Highly Potent Tyrosinase Inhibitory Activity

Ten 2-mercaptobenzimidazole (2-MBI) analogs were synthesized as potential tyrosinase inhibitors because mercapto-containing compounds can bind to copper ions at the active site of tyrosinase to inhibit enzyme activity. Nine 2-MBI analogs showed sub-micromolar IC50 values for mushroom tyrosinase monophenolase activity; analog 4 was 280-fold more potent than kojic acid, and in diphenolase activity, 6 was 970-fold more potent than kojic acid. The inhibition mode of the 2-MBI analogs was investigated using kinetic studies supported by docking simulations. Benzimidazoles without the 2-mercapto substituent of the 2-MBI analogs lost their tyrosinase inhibitory activity, implying that the 2-mercapto substituent plays an important role in tyrosinase inhibition. The 2-MBI analogs exerted potent antioxidant effects against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and reactive oxygen species (ROS). The results obtained from apple slices and human embryonic kidney cells (HEK-293) suggest that most 2-MBI analogs are sufficiently safe candidates to delay the browning of apple slices effectively. Thus, these results support the potential use of 2-MBI analogs as anti-browning agents in foods such as mushrooms, vegetables, and fruits.

CTHRC1 Induces Pancreatic Stellate Cells (PSCs) into Myofibroblast-like Cancer-Associated Fibroblasts (myCAFs)

[BACKGROUND] Collagen triple helix repeat containing-1 (CTHRC1) is a secreted protein that contributes to the progression of various cancers, including pancreatic cancer. The higher expression of CTHRC1 in tumor tissues is associated with poorer survival outcomes. However, its specific roles in tumor extracellular matrix (ECM) remodeling remain unclear. Our study aims to investigate the influences of CTHRC1 on pancreatic stellate cells (PSCs), a main source of ECM production in pancreatic cancer. [METHODS AND RESULTS] The analyses of the publicly available pancreatic cancer patient data revealed that CTHRC1 is mainly expressed in cancer stroma and highly correlated with ECM-related genes. An in vitro study showed that more than 40% of these genes can be upregulated by CTHRC1. CTHRC1 specifically activated PSC into myofibroblast-like cancer-associated fibroblasts (myCAFs), which are characterized by a significantly upregulated POSTN gene expression. Periostin (coded by the POSTN gene) has a central role in the CTHRC1-PSCs-cancer metastasis axis. Furthermore, CTHRC1 promoted pancreatic cancer cell proliferation through PSC activation to a greater extent than via direct stimulation. Proof-of-concept experiments showed that the long-term (4-week) inhibition of CTHRC1 led to significant tumor suppression and ECM reduction, and also resulted in an unexpected shift in the CAF subtype from myCAFs to inflammatory CAFs (iCAFs). [CONCLUSION] PSC activation was demonstrated to be the key molecular mechanism responsible for the tumor-promoting effects of CTHRC1, and CTHRC1 has a critical role in CAF subtype differentiation and tumor microenvironment (TME) remodeling. The inhibition of CTHRC1 as a therapeutic strategy for the treatment of pancreatic cancer warrants further investigation.

Compounds That Have an Anti-Biofilm Effect against Common Bacteria at Very Low Concentrations and Their Antibiotic Combination Effect

Two synthetic compounds, MHY1383, azo-resveratrol and MHY1387, 5-[4-hydroxy-3,5-methoxybenzy]-2-thioxodihydropyrimidine-4,6[1H,5H]-dione have been reported to have an anti-biofilm effect on Pseudomonas aeruginosa at very low concentrations (1-10 pM). Here, we investigated the anti-biofilm effects of these compounds in various bacteria. We found that MHY1383 significantly inhibited Escherichia coli, Bacillus subtilis, and Staphylococcus aureus biofilm formation at 1 pM, 1 nM, and 10 nM, respectively. MHY1387 also inhibited the biofilm formation of E. coli, B. subtilis, and S. aureus at 1 pM, 10 nM, and 100 pM, respectively. Both MHY1383 and MHY1387 showed medium-dependent anti-biofilm effects on Salmonella enterica at high concentrations (10 μM). We also tested the susceptibility to antibiotics by measuring the minimum inhibitory concentration (MIC) in various bacteria. When P. aeruginosa, E. coli, B. subtilis, S. enterica, and S. aureus were treated with MHY1383 or MHY1387 in combination with four different antibiotics, the MICs of carbenicillin against B. subtilis and S. aureus were lowered more than two-fold by the combination with MHY1387. However, in all other combinations, the MIC changed within two-fold. The results of this study suggest that MHY1383 and MHY1387 are effective anti-biofilm agents and can be used at very low concentrations against biofilms formed by various types of bacteria. We also suggest that even if a substance that inhibits biofilm is used together with antibiotics, it does not necessarily have the effect of lowering the MIC of the antibiotics.

Design, Synthesis, In Vitro, and In Silico Insights of 5-(Substituted benzylidene)-2-phenylthiazol-4(5H)-one Derivatives: A Novel Class of Anti-Melanogenic Compounds

(Z)-5-Benzylidene-2-phenylthiazol-4(5H)-one ((Z)-BPT) derivatives were designed by combining the structural characteristics of two tyrosinase inhibitors. The double-bond geometry of trisubstituted alkenes, (Z)-BPTs 1-14, was determined based on the ³J_C,Hβ coupling constant of ¹H-coupled ¹³C NMR spectra. Three (Z)-BPT derivatives (1-3) showed stronger tyrosinase inhibitory activities than kojic acid; in particular, 2 was to be 189-fold more potent than kojic acid. Kinetic analysis using mushroom tyrosinase indicated that 1 and 2 were competitive inhibitors, whereas 3 was a mixed-type inhibitor. The in silico results revealed that 1-3 could strongly bind to the active sites of mushroom and human tyrosinases, supporting the kinetic results. Derivatives 1 and 2 decreased the intracellular melanin contents in a concentration-dependent manner in B16F10 cells, and their anti-melanogenic efficacy exceeded that of kojic acid. The anti-tyrosinase activity of 1 and 2 in B16F10 cells was similar to their anti-melanogenic effects, suggesting that their anti-melanogenic effects were primarily owing to their anti-tyrosinase activity. Western blotting of B16F10 cells revealed that the derivatives 1 and 2 inhibited tyrosinase expression, which partially contributes to their anti-melanogenic ability. Several derivatives, including 2 and 3, exhibited potent antioxidant activities against ABTS cation radicals, DPPH radicals, ROS, and peroxynitrite. These results suggest that (Z)-BPT derivatives 1 and 2 have promising potential as novel anti-melanogenic agents.

Design and Synthesis of (Z)-2-(Benzylamino)-5-benzylidenethiazol-4(5H)-one Derivatives as Tyrosinase Inhibitors and Their Anti-Melanogenic and Antioxidant Effects

In this study, (Z)-2-(benzylamino)-5-benzylidenethiazol-4(5H)-one (BABT) derivatives were designed as tyrosinase inhibitors based on the structure of MHY2081, using a simplified approach. Of the 14 BABT derivatives synthesized, two derivatives ((Z)-2-(benzylamino)-5-(3-hydroxy-4-methoxybenzylidene)thiazol-4(5H)-one [7] and (Z)-2-(benzylamino)-5-(2,4-dihydroxybenzylidene)thiazol-4(5H)-one [8]) showed more potent mushroom tyrosinase inhibitory activities than kojic acid, regardless of the substrate used; in particular, compound 8 was 106-fold more potent than kojic acid when l-tyrosine was used as the substrate. Analysis of Lineweaver-Burk plots for 7 and 8 indicated that they were competitive inhibitors, which was confirmed via in silico docking. In experiments using B16F10 cells, 8 exerted a greater ability to inhibit melanin production than kojic acid, and it inhibited cellular tyrosinase activity in a concentration-dependent manner, indicating that the anti-melanogenic effect of 8 is attributable to its ability to inhibit tyrosinase. In addition, 8 exhibited strong antioxidant activity to scavenge 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals and peroxynitrite and inhibited the expression of melanogenesis-associated proteins (tyrosinase and microphthalmia-associated transcription factor). These results suggest that BABT derivative 8 is a promising candidate for the treatment of hyperpigmentation-related diseases, owing to its inhibition of melanogenesis-associated protein expression, direct tyrosinase inhibition, and antioxidant activity.

Design and Synthesis of (Z)-5-(Substituted benzylidene)-3-cyclohexyl-2-thioxothiazolidin-4-one Analogues as Anti-Tyrosinase and Antioxidant Compounds: In Vitro and In Silico Insights

Many compounds containing the β-phenyl-α,β-unsaturated carbonyl (PUSC) scaffold, including cinnamamide derivatives, have been shown to inhibit tyrosinase potently in vitro and in vivo. Structural changes to cinnamamide derivatives were produced by adding a dithionate functional group to provide eight (Z)-5-(substituted benzylidene)-3-cyclohexyl-2-thioxothiazolidin-4-one analogs with high log p values for skin. These analogs were synthesized using a two-step reaction, and their stereochemistry was confirmed using the ³J_C4-Hβ values of C4 measured in proton-coupled ¹³C mode. Analogs 2 (IC₅₀ = 5.21 ± 0.86 µM) and 3 (IC₅₀ = 1.03 ± 0.14 µM) more potently inhibited mushroom tyrosinase than kojic acid (IC₅₀ = 25.26 ± 1.10 µM). Docking results showed 2 binds strongly to the active site of tyrosinase, while 3 binds strongly to an allosteric site. Kinetic studies using l-tyrosine as substrate indicated 2 and 3 competitively and non-competitively inhibit tyrosinase, respectively, which was supported by our docking results. In B16F10 cells, 3 significantly and concentration-dependently reduced α–MSH plus IBMX induced increases in cellular tyrosinase activity and melanin production and the similarity between these inhibitory patterns implied that the anti-melanogenic effect of 3 might be due to its tyrosinase-inhibitory ability. In addition, 2 and 3 exhibited strong antioxidant effects; for example, they reduced ROS and ONOO^– levels and exhibited radical scavenging activities, suggesting that these effects might underlie their anti-melanogenic effects. Furthermore, 3 suppressed the expressions of melanogenesis-associated proteins and genes in B16F10 cells. These results suggest (Z)-5-(substituted benzylidene)-3-cyclohexyl-2-thioxothiazolidin-4-one analogs offer a means of producing novel anti-melanogenesis agents.

High preoperative gait variability is a prognostic predictor of gait and balance in Parkinson disease patients with deep brain stimulation

INTRODUCTION

The objective biomarker for prediction of gait and balance in the long-term follow-up of Parkinson's disease(PD) patients with subthalamic nucleus deep brain stimulation(STN-DBS) has not yet been elucidated. We investigated the value of pre-operative quantitative gait parameters for the prediction of long-term prognosis of gait in PD patients with DBS.

METHODS

We retrospectively collected gait videos(both medication ON/OFF states) of PD patients recorded as preoperative evaluation before STN DBS. We enrolled patients who were followed-up for more than 5 years after the surgery from 2006 to 2014. We derived objective gait parameters from video-based gait analysis algorithm. We defined the clinical milestones of frequent falling, impaired walking, and loss of autonomy based on the Unified Parkinson's disease rating scale and Hoehn and Yahr stage, which were regularly followed up to 156 months after surgery. We calculated hazard ratios(HRs) of baseline gait parameters for predicting the clinical milestones.

RESULTS

A total of 96 gait videos from 63 PD patients were analyzed. The mean follow-up duration(standard deviation) was 88.0(34.2) months after surgery. Relatively high (>mean + 1 standard deviation) variability for step length, step time and stride time (HR = 2.92[1.02-8.33], 3.91[1.38-11.11] and 7.16[2.09-24.52],respectively) in medication-ON state significantly predicted reaching any of the three clinical milestones of frequent falling, impaired walking and loss of autonomy. Gait parameters from the medication-OFF state did not predict any clinical milestone.

CONCLUSIONS

High preoperative gait variability from the medication-ON state predicts long-term outcomes for gait and balance in PD patients with STN DBS.

Porphyromonas gingivalis Impairs Oral Epithelial Barrier through Targeting GRHL2

Oral mucosa provides the first line of defense against a diverse array of environmental and microbial irritants by forming the barrier of epithelial cells interconnected by multiprotein tight junctions (TJ), adherens junctions, desmosomes, and gap junction complexes. Grainyhead-like 2 (GRHL2), an epithelial-specific transcription factor, may play a role in the formation of the mucosal epithelial barrier, as it regulates the expression of the junction proteins. The current study investigated the role of GRHL2 in the Porphyromonas gingivalis (Pg)-induced impairment of epithelial barrier functions. Exposure of human oral keratinocytes (HOK-16B and OKF6 cells) to Pg or Pg-derived lipopolysaccharides (Pg LPSs) led to rapid loss of endogenous GRHL2 and the junction proteins (e.g., zonula occludens, E-cadherin, claudins, and occludin). GRHL2 directly regulated the expression levels of the junction proteins and the epithelial permeability for small molecules (e.g., dextrans and Pg bacteria). To explore the functional role of GRHL2 in oral mucosal barrier, we used a Grhl2 conditional knockout (KO) mouse model, which allows for epithelial tissue-specific Grhl2 KO in an inducible manner. Grhl2 KO impaired the expression of the junction proteins at the junctional epithelium and increased the alveolar bone loss in the ligature-induced periodontitis model. Fluorescence in situ hybridization revealed increased epithelial penetration of oral bacteria in Grhl2 KO mice compared with the wild-type mice. Also, blood loadings of oral bacteria (e.g., Bacteroides, Bacillus, Firmicutes, β-proteobacteria, and Spirochetes) were significantly elevated in Grhl2 KO mice compared to the wild-type littermates. These data indicate that Pg bacteria may enhance paracellular penetration through oral mucosa in part by targeting the expression of GRHL2 in the oral epithelial cells, which then impairs the epithelial barrier by inhibition of junction protein expression, resulting in increased alveolar tissue destruction and systemic bacteremia.

Clastic cells are absent around the root surface in pulp-exposed periapical periodontitis lesions in mice

INTRODUCTION

Clastic cells, originating from the monocyte-macrophage lineage, resorb mineralized tissues. In periapical periodontitis, alveolar bone around the tooth apex becomes resorbed; however, the roots of the teeth are often left intact by yet unknown mechanisms. Here, we examined the status of clastic cells in a periapical periodontitis model in mice.

METHODS

Periapical periodontitis was induced by performing pulp exposure on the maxillary first molar. The contralateral maxillary first molar was used as a control. The maxillae were harvested, fixed, and subjected to μCT scanning and three-dimensional volumetric analysis. TRAP staining was performed, and osteoclasts were quantified. Immunohistochemical staining was performed for RANKL, OPG, and F4/80, a marker for macrophages.

RESULTS

At the apex of the tooth, pulp exposure resulted in periapical radiolucency with mineralized tissues at the surrounding bone surfaces but not on the root surfaces. Histologically, clastic cells were present on the bone surfaces but absent around the root surfaces. Expression of F4/80 and RANKL was not found at close proximity to the root surfaces, but OPG was globally expressed.

CONCLUSION

The absence of clastic cells around the root surface of pulp-exposed teeth, in part, is associated with the lack of macrophages and RANKL expression.

Cancer upregulated gene 2 induces epithelial-mesenchymal transition of human lung cancer cells via TGF-β signaling

Cancer upregulated gene 2 (CUG2) enhances cell migration and invasion, but the underlying mechanism has not been revealed. Herein, CUG2 decreased the expression of E-cadherin and increased the expression of N-cadherin and vimentin, characteristics of the epithelial-mesenchymal transition (EMT). A CUG2 deletion mutant, lacking interaction with nucleophosmin 1 (NPM1), or suppression of NPM1 reduced wound healing and cell invasion, indicating that CUG2-mediated EMT requires NPM1. CUG2 enhanced activation of Smad2/3 and expression of Snail and Twist, while the CUG2 silence decreased these TGF-β signaling pathways, leading to suppression of EMT. NPM silence also inhibited the CUG2-induced TGF-β signaling. These results suggest that TGF-β signaling is involved in CUG2-induced EMT. Treatment with EW-7197, a novel inhibitor of TGF-β signaling, diminished CUG2-mediated EMT and inhibition of Akt, ERK, JNK, and p38 MAPK, non-canonical TGF-β signaling molecules, also decreased expression of Smad2/3, Snail and Twist, leading to inhibition of EMT. The results confirm that TGF-β signaling is essential for CUG2-mediated EMT. Interestingly, TGF-β enhanced CUG2 expression. We further found that both CUG2-induced TGF-β production and TGF-β-induced CUG2 up-regulation required a physical interaction between Sp1 and Smad2/3 in the CUG2 and TGF-β promoter, as demonstrated by a promoter reporter assay, immunoprecipitation, and ChIP assay. These results indicated close crosstalk between CUG2 and TGF-β. Conversely, suppression of CUG2 or NPM1 did not completely inhibit TGF-β-induced EMT, indicating that the effect of TGF-β on EMT is dominant over the effect of CUG2 on EMT. Collectively, our findings suggest that CUG2 induces the EMT via TGF-β signaling.

Human Papillomavirus 16 E6 Induces FoxM1B in Oral Keratinocytes through GRHL2

High-risk human papillomavirus (HPV) is a major risk factor for oral and pharyngeal cancers (OPCs), yet the detailed mechanisms by which HPV promotes OPCs are not understood. Forkhead box M1B (FoxM1B) is an oncogene essential for cell cycle progression and tumorigenesis, and it is aberrantly overexpressed in many tumors. We previously showed that FoxM1B was the putative target of an epithelial-specific transcription factor, Grainyhead-like 2 (GRHL2). In the current study, we demonstrate that HPV type 16 (HPV-16) E6 induces FoxM1B in human oral keratinocytes (HOKs) and tonsillar epithelial cells (TECs) in part through GRHL2. FoxM1B was barely detectable in cultured normal human oral keratinocytes (NHOKs) and progressively increased in immortalized HOKs harboring HPV-16 genome (HOK-16B) and tumorigenic HOK-16B/BaP-T cells. Retroviral expression of HPV-16 E6 and/or E7 in NHOKs, TECs, and hypopharyngeal carcinoma cells (FaDu) revealed induction of FoxM1B and GRHL2 by the E6 protein but not E7. Both GRHL2 and FoxM1B were strongly induced in the epidermis of HPV-16 E6 transgenic mice and HPV⁺ oral squamous cell carcinomas. Ectopic expression of FoxM1B led to acquisition of transformed phenotype in HOK-16B cells. Loss of FoxM1B by lentiviral short hairpin RNA vector or chemical inhibitor led to elimination of tumorigenic characteristics of HOK-16B/BaP-T cells. Luciferase reporter assay revealed that GRHL2 directly bound and regulated the FoxM1B gene promoter activity. Using epithelial-specific Grhl2 conditional knockout mice, we exposed wild-type (WT) and Grhl2 KO mice to 4-nitroquinolin 1-oxide (4-NQO), which led to induction of FoxM1B in the tongue tissues and rampant oral tumor development in the WT mice. However, 4-NQO exposure failed to induce tongue tumors or induction of FoxM1B expression in Grhl2 KO mice. Collectively, these results indicate that HPV-16 induces FoxM1B in part through GRHL2 transcriptional activity and that elevated FoxM1B level is required for oropharyngeal cancer development.

Sarpogrelate Based Triple Antiplatelet Therapy Improved Left Ventricular Systolic Function in Acute Myocardial Infarction: Retrospective Study

PURPOSE

The purpose of this study was to assess the potential benefit of a 5-hydroxytryptamine receptor antagonist, sarpogrelate-based triple antiplatelet therapy (TAPT) in comparison with dual antiplatelet therapy (DAPT) in patients undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI).

MATERIALS AND METHODS

119 patients of STEMI were retrospectively assessed. All patients received aspirin and clopidogrel per standard of care. Among them, 53 patients received an additional loading dose of sarpogrelate and a maintenance dose for 6 months post-PCI (TAPT group), while others did not (DAPT group).

RESULTS

The rates of complete ST-segment resolution at 30 minutes post-PCI and post-procedural thrombolysis in myocardial infarction flow were not significantly different between the two groups (52.8% vs. 48.5%, p=0.200; 92.5% vs. 89.4%, p=0.080). In addition, no significant differences were observed between the two groups with regard to 30-day and 12-month clinical outcomes (cardiac death, myocardial infarction, stent thrombosis, target vessel revascularization, and severe bleeding). Meanwhile, improvement in left ventricular (LV) systolic function was observed in the TAPT group [ΔLV ejection fraction (LVEF)=17.1±9.4%, p<0.001; Δglobal longitudinal strain (GLS)=-9.4±4.2% , p<0.001] at 6 months, whereas it was not in the DAPT group (ΔLVEF= 8.8±6.5%, p=0.090; ΔGLS=-4.6±3.4%, p=0.106). In multivariate analyses, TAPT was an independent predictor for LV functional recovery (odds ratio, 2.61; 95% confidence interval, 1.16-5.87; p=0.003).

CONCLUSION

Sarpogrelate-based TAPT improved LV systolic function at 6 months in STEMI patients undergoing primary PCI.

Conversion of Normal To Malignant Phenotype: Telomere Shortening, Telomerase Activation, and Genomic Instability During Immortalization of Human Oral Keratinocytes

Normal somatic cells terminate their replicative life span through a pathway leading to cellular senescence, which is triggered by activation of p53 and/or pRb in response to critically shortened telomere DNA. Potentially neoplastic cells must first overcome the senescence checkpoint mechanisms and subsequently activate telomerase to propagate indefinitely. Although telomerase activation is closely associated with cellular immortality, telomerase alone is not sufficient to warrant tumorigenicity. Environmental factors, including chemical carcinogens and viral infection, often contribute to aberrant changes leading to tumorigenic conversion of normal cells. Of particular importance in oral cancer development are tobacco-related chemical carcinogens and human papillomavirus (HPV) infection. To describe the molecular mechanisms by which these environmental factors facilitate the genesis of oral cancer, we first established an in vitro multistep oral carcinogenesis model by sequential exposure of normal human oral keratinocytes (NHOK) to "high risk" HPV and chemical carcinogens. Upon introduction of the HPV genome, the cells bypassed the senescence checkpoint and entered into an extended, but not immortal, life span during which telomere DNA continued to shorten. In a few immortal clones surviving beyond the crisis, we found a marked elevation of telomerase activity and stabilization of telomere length. Furthermore, the E6 and E7 oncoproteins of "high risk" HPV disrupted the cell cycle control and DNA repair in immortalized HOK, and enhanced mutation frequency resulting from genomic instability. However, HPV infection alone failed to give rise to a tumorigenic cell population, which required further exposure to chemical carcinogens in addition to HPV infection. Analysis of the data presented suggests that oral carcinogenesis is a series of discrete genetic alterations that result from a continued genotoxic challenge by environmental risk factors. Our in vitro model may be useful for investigators with interest in furthering our understanding of oral carcinogenesis.

Effects of Bioactive Compounds on Odontogenic Differentiation and Mineralization

Direct pulp capping involves the placement of dental materials directly onto vital pulp tissues after deep caries removal to stimulate the regeneration of reparative dentin. This physical barrier will serve as a "biological seal" between these materials and the pulp tissue. Although numerous direct pulp capping materials are available, the use of small bioactive compounds that can potently stimulate and expedite reparative dentin formation is still underexplored. Here, the authors compared and evaluated the pro-osteogenic and pro-odontogenic effects of 4 small bioactive compounds- phenamil (Phen), purmorphamine (Pur), genistein (Gen), and metformin (Met). The authors found that these compounds at noncytotoxic concentrations induced differentiation and mineralization of preosteoblastic MC3T3-E1 cells and preodontoblastic dental pulp stem cells (DPSCs) in a dose-dependent manner. Among them, Phen consistently and potently induced differentiation and mineralization in vitro. A single treatment with Phen was sufficient to enhance the mineralization potential of DPSCs in vitro. More importantly, Phen-treated DPSCs showed enhanced odontogenic differentiation and mineralization in vivo. Our study suggests that these small bioactive compounds merit further study for their potential clinical use as pulp capping materials.

Epigenetic gene regulation by histone demethylases: emerging role in oncogenesis and inflammation

Histone N-terminal tails of nucleosomes are the sites of complex regulation of gene expression through post-translational modifications. Among these modifications, histone methylation had long been associated with permanent gene inactivation until the discovery of Lys-specific demethylase (LSD1), which is responsible for dynamic gene regulation. There are more than 30 members of the Lys demethylase (KDM) family, and with exception of LSD1 and LSD2, all other KDMs possess the Jumonji C (JmjC) domain exhibiting demethylase activity and require unique cofactors, for example, Fe(II) and α-ketoglutarate. These cofactors have been targeted when devising KDM inhibitors, which may yield therapeutic benefit. KDMs and their counterpart Lys methyltransferases (KMTs) regulate multiple biological processes, including oncogenesis and inflammation. KDMs' functional interactions with retinoblastoma (Rb) and E2 factor (E2F) target promoters illustrate their regulatory role in cell cycle progression and oncogenesis. Recent findings also demonstrate the control of inflammation and immune functions by KDMs, such as KDM6B that regulates the pro-inflammatory gene expression and CD4⁺ T helper (Th) cell lineage determination. This review will highlight the mechanisms by which KDMs and KMTs regulate the target gene expression and how epigenetic mechanisms may be applied to our understanding of oral inflammation.

Atypia of undetermined significance on thyroid fine needle aspiration - risk factors for malignancy

OBJECTIVES

This study is designed to determine the clinical predictors of malignancy in the atypia of undetermined significance (AUS) category resulted from thyroid fine needle aspiration (FNA).

DESIGN

Retrospective cohort study.

SETTING

Dong-A University Medical Center, Busan, Korea.

PARTICIPANTS

Sixty-two patients who underwent thyroid surgery from January 2010 to December 2013, following a diagnosis of AUS from preoperative thyroid FNA.

MAIN OUTCOME MEASURES

We investigated the age, gender, maximum size and site of the nodules, ultrasonographic findings, cytological features, BRAF gene mutation, surgical method, number of AUS on repeated FNA and final pathologic results.

RESULTS

Forty-one of sixty-two patients underwent total thyroidectomy and the rest had lobectomy. The final pathologic results were 41 malignancies and 21 benign diseases. Nodules less than 1.5 cm, ultrasonographic findings suggestive of malignancy were risk factors for malignancy on univariated analysis (P < 0.001). Multivariated analysis showed that nodules less than 1.5 cm, ultrasonographic findings suggestive of malignancy and more than 2 results of atypia from repeated FNAs were significant risk factors for malignancy (P < 0.001). A BRAF gene mutation analysis was performed in 38 patients, and 13 patients had the mutation. All patients with the BRAF gene mutation had been diagnosed with papillary thyroid cancer (P > 0.05).

CONCLUSIONS

We recommend close observation or diagnostic surgery in patients with nodules <1.5 cm and with two or more malignant ultrasound feature and a BRAF mutation, or with two or more AUS findings on repeated FNAs.

The Role of ORAI1 in the Odontogenic Differentiation of Human Dental Pulp Stem Cells

Pulp capping, or placing dental materials directly onto the vital pulp tissues of affected teeth, is a dental procedure that aims to regenerate reparative dentin. Several pulp capping materials are clinically being used, and calcium ion (Ca(2+)) released from these materials is known to mediate reparative dentin formation. ORAI1 is an essential pore subunit of store-operated Ca(2+) entry (SOCE), which is a major Ca(2+) influx pathway in most nonexcitable cells. Here, we evaluated the role of ORAI1 in mediating the odontogenic differentiation and mineralization of dental pulp stem cells (DPSCs). During the odontogenic differentiation of DPSCs, the expression of ORAI1 increased in a time-dependent manner. DPSCs knocked down with ORAI1 shRNA (DPSC/ORAI1sh) or overexpressed with dominant negative mutant ORAI1(E106Q) (DPSC/E106Q) exhibited the inhibition of Ca(2+) influx and suppression of odontogenic differentiation and mineralization as demonstrated by alkaline phosphatase (ALP) activity/staining as well as alizarin red S staining when compared with DPSCs of their respective control groups (DPSC/CTLsh and DPSC/CTL). The gene expression for odontogenic differentiation markers such as osteocalcin, bone sialoprotein, and dentin matrix protein 1 (DMP1) was also suppressed. When DPSC/CTL or DPSC/E106Q cells were subcutaneously transplanted into nude mice, DPSC/CTL cells induced mineralized tissue formation with significant increases in ALP and DMP1 staining in vivo, whereas DPSC/E106Q cells did not. Collectively, our data showed that ORAI1 plays critical roles in the odontogenic differentiation and mineralization of DPSCs by regulating Ca(2+) influx and that ORAI1 may be a therapeutic target to enhance reparative dentin formation.

Label-free detection of ApoE4-mediated β-amyloid aggregation on single nanoparticle uncovering Alzheimer's disease

Beta amyloid (Aβ) deposition is a pathological milestone of Alzheimer's disease (AD). This is facilitated by an isoform of Apolipoprotein E4 (ApoE4), which is a dominant risk factor for AD. However, current in vitro Aβ aggregation assays were performed in extreme conditions not linked to physiological conditions, to understand the mechanism of Aβ induced neurotoxicity. Here, we present a simple method for the ApoE4-mediated Aβ aggregation at physiological conditions using single gold nanoparticle based on localized surface plasmon resonance (LSPR). It can be directly observed by dark-field microscope or even by the naked eye. Following LSPR principles, we used ApoE4 inducing Aβ42 self-assemblies on gold nanoparticles (AuNPs) surface via their surface charge interaction. Using physiologically mimic cerebrospinal fluid, we determined a detection limit of 1.5 pM for Aβ42 corresponding to the ~2.9 nm LSPR-peak shift under ApoE4. Interestingly, the result also shows that ApoE4 induces the aggregation of Aβ42 more specifically and rapidly than that of Aβ40. This is the first biomimetic platform for real-time detection of Aβ aggregation, mimicking biological conditions, which can be used to investigate AD directly.

Grainyhead-like 2 (GRHL2) inhibits keratinocyte differentiation through epigenetic mechanism

We recently identified Grainyhead-like 2 (GRHL2), a mammalian homolog of Grainyhead in Drosophila, to be a novel transcription factor that regulates hTERT gene expression and enhances proliferation of normal human epidermal keratinocytes (NHEK). In the current study, we show that GRHL2 impairs keratinocyte differentiation through transcriptional inhibition of the genes clustered at the epidermal differentiation complex (EDC), located at chromosome 1q21. Gene expression profiling and subsequent in vitro assays revealed consistent downregulation of EDC genes, for example, IVL, KRT1, FLG, LCEs, and SPRRs, in NHEK expressing exogenous GRHL2. In vivo binding assay by chromatin immunoprecipitation revealed GRHL2 association at the promoter regions of its target genes, many of which belong to EDC. Exogenous GRHL2 expression also inhibited recruitment of histone demethylase Jmjd3 to the EDC gene promoters and enhanced the level of histone 3 Lys 27 trimethylation enrichment at these promoters. Survey of GRHL2 expression in human skin tissues demonstrated enhanced protein and mRNA levels in chronic skin lesions with impaired keratinocyte differentiation, for example, atopic dermatitis and psoriasis, compared with normal epidermis. These data indicate that GRHL2 impairs epidermal differentiation by inhibiting EDC gene expression through epigenetic mechanisms and support its role in the hyperproliferative skin diseases.

Rifaximin Plus Levofloxacin-Based Rescue Regimen for the Eradication of Helicobacter pylori

Background/Aims

This study assessed the efficacy of a rifaximin plus levofloxacin-based rescue regimen in patients that had failed both triple and quadruple standard regimens for the eradication of Helicobacter pylori.

Methods

We treated patients for H. pylori between August 2009 and April 2011. The triple regimen consisted of combined treatment with amoxicillin, clarithromycin, and pantoprazole for 1 week. For failed cases, a quadruple regimen of tetracycline, metronidazole, bismuth dicitrate, and lansoprazole for 1 week was administered. The rescue regimen for persistently refractory cases was rifaximin 200 mg t.i.d., levofloxacin 500 mg q.d., and lansoprazole 15 mg b.i.d. for 1 week.

Results

In total, 482 patients were enrolled in this study. The eradication rates associated with the first and second regimens were 58% and 60%, respectively. Forty-seven out of 58 patients who failed with the second-line regimen received rifaximin plus levofloxacin-based third-line therapy. The eradication rate for the third regimen was 65%. The cumulative eradication rates were 58%, 85%, and 96% for each regimen, respectively.

Conclusions

A rifaximin plus levofloxacin-based regimen could be an alternative rescue therapy in patients with resistance to both triple and quadruple regimens for the eradication of H. pylori.

Bacterial diversity on different surfaces in urban freshwater

Microbial loads in freshwater systems have important implications in biogeochemical cycling in urban environments. Immersed surfaces in freshwaters provide surfaces for bacterial attachment and growth. Microorganisms that adhere initially to these surfaces play a critical role in biofilm formation and sustenance. Currently, there is little understanding on the type of organisms that initially adhere to different surfaces in urban canals. In this study, water from an urban stormwater canal was employed to allow bacteria to attach to different surfaces in a flowcell apparatus and understand the differences and changes in bacterial community structure. Bacterial communities were highly diverse on different surfaces as indicated by Jaccard's indices of 0.14-0.56. Bacteria on aluminium were the most diverse and on Plexiglas the least. Bacterial communities were highly dynamic in the early attachment phase and it changed by 59% between 3 and 6 h on aluminium. Specificity of attachment to surfaces was observed for some bacteria. Judicious use of materials in urban aquatic environment would help mitigate microbial load in urban waters.

Clinical and echocardiographic predictors of outcomes in patients with apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy (HC) is considered to have a favorable prognosis, but recent observations have suggested less benign clinical courses. We investigated the outcomes in patients with apical HC and evaluated the predictors. All 454 patients with apical HC (316 men, age 61 ± 11 years) were recruited. Major cardiovascular events (MACE) were defined as unplanned hospitalization because of heart failure, stroke, or cardiovascular mortality. The patients were divided into 2 groups: group 1 with MACE and group 2 without MACE. During the follow-up period (43 ± 20 months), the all-cause mortality rate was 9% (39 of 454), and 110 patients (25%) had MACE. The subjects in group 1 were older and a greater proportion had diabetes, hypertension, and atrial fibrillation. On the echocardiogram, the left atrial volume index (left atrial volume index 36 ± 17 vs 31 ± 12 ml/m(2)), transmitral E velocity (65 ± 17 vs 61 ± 16 cm/s), mitral annulus Ea velocity (4.5 ± 1.4 vs 5.1 ± 1.8 cm/s), Sa velocity (5.8 ± 1.4 vs 6.6 ± 1.4 cm/s), E/Ea ratio (15 ± 5 vs 13 ± 5), and right ventricular systolic pressure (31 ± 8 vs 28 ± 7 mm Hg) were significantly different between groups 1 and 2 (p <0.05 for all). The left atrial volume index (for each 1-ml/m(2) increase, hazard ratio 1.01, 95% confidence interval 1.00 to 1.03; p = 0.047), Sa velocity (hazard ratio 0.83, 95% confidence interval 0.72 to 0.96, p = 0.014), and E/Ea ratio (hazard ratio 1.04, 95% confidence interval 1.00 to 1.09, p = 0.030) were independent predictors of a poor prognosis, along with age and the presence of diabetes or hypertension. In conclusion, the clinical outcomes of patients with apical HC were less benign in older patients and in those with hypertension or diabetes. In addition, the left atrial volume index, Sa velocity, and E/Ea ratio were predicters of a poor prognosis in patients with apical HC.

Bisphosphonates induce senescence in normal human oral keratinocytes

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) commonly occurs in individuals receiving bisphosphonates (BPs) with clinical manifestations of the exposed necrotic bone. Although defective wound healing of soft tissue is frequently, if not always, observed in BRONJ, the effects of BPs on oral soft tissue or cells remain unknown. To investigate the effects of BPs on cells of oral mucosal tissue, we studied the effect of pamidronate (PAM), one of the BPs most commonly administered to cancer patients, on the phenotypes of normal human oral keratinocytes (NHOK) and fibroblasts (NHOF). When exposed to PAM at 10 µM, NHOK, not NHOF, underwent senescence: NHOK overexpressed senescence-associated β-galactosidase (SA-β-Gal), p16INK4A, IL-6, and IL-8. When exposed to a higher level (50 µM) of PAM, NHOK maintained senescent phenotypes, but NHOF underwent apoptosis. PAM-induced senescence in NHOK is mediated, in part, via geranylgeranylation of the mevalonate pathway. Our in vitro 3D oral mucosal tissue construction studies further demonstrated that PAM induced senescence and impaired re-epithelialization of oral mucosa. Analysis of these data indicates that premature senescence of oral mucosal cells and subsequent defective soft-tissue wound healing might be partly responsible for the development of BRONJ in individuals receiving PAM or other BPs.

The role of 18F-FDG PET/CT in the evaluation of gastric cancer recurrence after curative gastrectomy

PURPOSE

(18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) scans are frequently performed for the screening or staging of malignant tumors. This study aimed to assess the usefulness of (18)F-FDG PET/CT in detection of gastric cancer recurrence after curative gastrectomy.

MATERIALS AND METHODS

Eighty nine patients who had undergone curative gastrectomy due to gastric cancer and had (18)F-FDG PET/CT and contrast CT scans within 2 weeks for surveillance in asymptomatic patients (n = 11) or to clarify suspected recurrence (n = 78) were consecutively collected and retrospectively analyzed. They had clinical follow-up for at least 12 months after PET/CT and CT scans.

RESULTS

Fifteen of the 89 patients (16.9%) were diagnosed with recurrent gastric cancer in 21 organs. Forty one organs showed an increase in FDG uptake, and only 9 of these organs were diagnosed with recurrent gastric cancer by (18)F-FDG PET/CT. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the (18)F-FDG PET/CT were 42.9%, 59.7%, 29.3%, 78.2%, and 57.3%, respectively. On the CT scan, 18 of 21 recurrent gastric cancers were detected, and 7 cases were in agreement with the (18)F-FDG PET/CT. The sensitivity and specificity of the CT scan were 85.8% and 87.3%, respectively, which are superior to the (18)F-FDG PET/CT. When we diagnosed a recurrence based on either (18)F-FDG PET/CT or CT scans, the sensitivity increased to 95.2% and the specificity decreased to 45.6%, when compared with the contrast CT scan alone.

CONCLUSION

(18)F-FDG PET/CT is an insufficient diagnostic method in detection of recurrence after curative gastrectomy, and even less accurate than contrast CT scan alone.

Implantable cardioverter-defibrillator implantation in a patient with atrial standstill

We report a 55-year-old female patient who presented with no P waves but with a wide QRS complex escape rhythm at 44 beats/min and prolonged QTc of 0.55 seconds on ECG. The patient had recurrence of ventricular fibrillations and loss of consciousness, and underwent defibrillation and cardiopulmonary resuscitation (CPR) several times because of cardiac arrest. The transthoracic echocardiography showed dilated cardiomyopathy and enlargement of both atria. The Doppler echocardiography documented the absence of A wave in the tricuspid and mitral valve flow. An electrophysiologic study demonstrated electrical inactivity in the right and left atria. Atrial pacing with maximum output did not capture the atria. These findings together with her electrocardiographic finding indicated atrial standstill. Sudden cardiac death was her first clinical manifestation of ventricular arrhythmia. The patient remained asymptomatic after receiving a single chamber implantable cardioverter-defibrillator (ICD) with VVI pacemaker function.

Pharmacokinetic Interaction Between Oltipraz and Silymarin in Rats

ABSTRACT. Purpose: To evaluate the pharmacokinetic interaction between oltipraz and silymarin after intravenous and oral administration of both drugs to male Sprague–Dawley rats. Methods: Oltipraz (single doses of 10 and 30 mg/kg for intravenous and oral administration, respectively), silymarin (single doses of 50 and 100 mg/kg for intravenous and oral administration, respectively, and 14 days oral administration of 100 mg/kg), alone and together were administered to control rats. Results: The pharmacokinetic parameters of oltipraz did not significantly altered by silymarin. However, after intravenous administration of the drugs together, the AUCs of unconjugated, conjugated, and total (unconjugated plus conjugated) silibinin were significantly different (32.7% decrease, and 32.1% and 27.2% increase, respectively), and total and (CL) and non-renal (CLNR ) clearance of unconjugated silibinin were significantly faster (49.4% and 61.1% increase, respectively) than those of silymarin alone (without oltipraz). After oral administration of silymarin with or without oltipraz, however, the pharmacokinetic parameters of unconjugated, conjugated, and total silibinin were comparable. Conclusions: After single intravenous administration of the drugs together, the AUC of unconjugated silibinin was significantly smaller, but that of both conjugated and total silibinin was significantly greater. This could have been due to an increase in the formation of conjugates (glucuronidation and sulfation) of silibinin as induced by oltipraz. After simultaneous oral administration of the drugs, however, the AUCs (or AUC0−12 h) of unconjugated, conjugated, and total silibinin were comparable.

Regulation of the hTERT promoter activity by MSH2, the hnRNPs K and D, and GRHL2 in human oral squamous cell carcinoma cells

Higher expression of human telomerase reverse transcriptase (hTERT) and subsequent activation of telomerase occur during cellular immortalization and are maintained in cancer cells. To understand the mode of hTERT expression in cancer cells, we identified cancer-specific trans-regulatory proteins that interact with the hTERT promoter, using the promoter magnetic precipitation assay coupled to mass spectrometry (PMS-MS). The identified proteins include MutS homologue 2 (MSH2), heterogeneous nuclear ribonucleoprotein (hnRNP) D, hnRNP K, and Grainyhead-like 2 (GRHL2). We noticed higher expression of these proteins in human oral squamous cell carcinoma (OSCC) cells than in normal cells, which do not exhibit telomerase activity. Knockdown of MSH2, hnRNP D and GRHL2 resulted in notable reduction of the hTERT promoter activity in tested cancer cells. Silencing of the above genes resulted in the significant reduction of telomerase activity in OSCC cells. Interestingly, among the four identified genes, silencing of GRHL2 was essential in reducing telomerase activity and viability of tested cancer cells. These results suggest a possible role of GRHL2 in telomerase activation during cellular immortalization.

Interleukin-6 induces proliferation in adult spinal cord-derived neural progenitors via the JAK2/STAT3 pathway with EGF-induced MAPK phosphorylation

INTRODUCTION

In a previous study, we observed cell proliferation 3 days after spinal cord injury, and levels of interleukin-6 (IL-6) and epidermal growth factor (EGF) had significantly increased in the region of the injury.

OBJECTIVES

The purpose of the new study described here was to evaluate the roles of IL-6 and EGF after traumatic damage to the spinal cord having isolated neural progenitor cells (NPC) from adult mice.

METHODS AND RESULTS

Evidence provided by the trypan blue dye exclusion assay, 5-bromodeoxyuridine immunoreactivity and Western blot analysis indicated that IL-6 and EGF induced proliferation of these spinal cord-derived NPCs via phosphorylation of Janus-activated kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) and mitogen-activated protein kinases (MAPK), respectively. Combined treatment with IL-6 and EGF accelerated proliferation of cells synergistically and phosphorylation of STAT3 and extracellular signal-regulated kinase 1/2 (Erk1/2). Furthermore, AG490 and AG1478, JAK2 inhibitor and EGFR inhibitor, respectively, prevented the IL-6- and EGF-induced proliferation of the cells. Interestingly, IL-6-activated MAPKs but EGF did not influence JAK2/STAT3 activation; AG490 specifically inhibited IL-6-induced Erk1/2 phosphorylation without affecting IL-6-induced phosphorylation of Raf and MEK1/2. These results indicate that IL-6 is directly involved in Erk1/2 activation via JAK2 and that Erk1/2 provides a signal bridge between the IL-6-induced JAK2/STAT3 pathway and EGF-induced MAPK pathway.

CONCLUSIONS

Our study is the first demonstration of IL-6- and EGF-stimulated proliferation of spinal cord progenitor cells via JAK2/STAT3 and MAPK signalling pathways. These pathways play key roles in repopulation and regeneration of spinal cord tissue after injury. It may represent novel therapeutic targets for pharmacological intervention in central nervous system disease, including spinal cord injury.

The Antimicrobial Effect of Silver Ion Impregnation into Endodontic Sealer against Streptococcus mutans

Pulpal and periradicular diseases are primarily caused by bacterial invasion of the root canal system as a result of caries progression. The presence of residual bacteria at the time of root canal completion (obturation) is associated with significantly higher rate of treatment failure. Re-infection of obturated root canals can be potentially prevented by enhancing the antibacterial activities of root canal obturation materials. We evaluated, in an in vitro model, the antimicrobial efficacy of silver ions added to a common endodontic sealer. For that purpose we performed growth inhibition studies and bacterial viability tests. We measured the zone of inhibition, optical density and performed confocal laser scanning microscopy. Our results show that the silver ions enhance the antimicrobial activity of the root canal sealer against Streptococcus mutans. This study approach may hold promise for studying other biologically based therapies and therefore increasing the success rate of routine orthograde root canal treatment.

Elevated Bmi-1 expression is associated with dysplastic cell transformation during oral carcinogenesis and is required for cancer cell replication and survival

Bmi-1 is a polycomb group protein that was identified as c-myc cooperating oncogene in murine lymphomagenesis. The current study was undertaken to determine the role of Bmi-1 in human oral carcinogenesis. Bmi-1 protein and RNA expression levels were markedly enhanced in the cells of oral squamous cell carcinomas (OSCC) compared with that of normal human oral keratinocytes (NHOK). Enhanced-Bmi-1 expression was also detected in situ in the archived oral mucosal tissues with cancerous and precancerous histopathology, including that of mild epithelial dysplasia. Thus, Bmi-1 expression occurs at a very early stage in oral carcinogenesis. To determine the biological role of Bmi-1 in cell proliferation, endogenous Bmi-1 was knocked down in actively proliferating SCC4 cells and NHOK by RNA interference. After Bmi-1 knockdown, cell replication was severely retarded. However, the expression of p16^INK4A, a known cellular target of Bmi-1, was not changed in cells with or without Bmi-1 knockdown. Furthermore, Bmi-1 knockdown in HOK-16B-BaP-T cells, in which the p16^INK4A/pRb pathway was abrogated, led to immediate arrest of replication and loss of viable cells. Thus, our data suggest that Bmi-1 may act through p16^INK4A-independent pathways to regulate cellular proliferation during oral cancer progression.

Correlation between levels of N-terminal pro-B-type natriuretic peptide and degrees of heart failure

BACKGROUND

The N-terminal fragment of pro Brain Natriuretic Peptide (NT-pro BNP) is a neuro-hormone synthesized in the cardiac ventricles in response to increased wall tension. The purpose of this study was to assess the correlation between the NT-pro BNP levels and the New York Heart Association function class (NYHA Fc) of dyspnea and echocardiographic findings for the patients who visited our cardiology departments.

METHODS

From October, 2002 to April, 2003, serum NT-pro BNP levels were measured in 348 patients who visited the Samsung Medical Center and the Jong Koo Lee Heart Clinic.

RESULTS

The NT-pro BNP levels were increased with the progression of NYHA Fc of dyspnea (p < 0.001 by ANOVA), the increase in the systolic left ventricular internal dimension (p < 0.05), and the decrease in the ejection fraction (p < 0.01). For the NYHA Fc I patients, the NT-pro BNP levels were positively correlated with age (0 < 0.001) and left atrial size (p < 0.001). For the patients with ischemic heart disease, the NT-pro BNP levels were also positively correlated with the NYHA Fc (p < 0.001 by ANOVA). The NT-pro BNP levels were increased with the increase in the systolic (p < 0.001) and diastolic pressure (p = 0.017), the left ventricular internal dimension as well as the decrease in the ejection fraction (p < 0.001). The area under the receiver operating characteristic (ROC) curve for the NT-pro BNP levels was 0.994 (95% confidence interval, 0.979-0.999), and the most reliable cut-off level for the NT-pro BNP was 293.6 pg/mL.

CONCLUSION

The NT-pro BNP levels were positively correlated with the NYHA Fc of dyspnea and the systolic dysfunction for the patients who visited our cardiology departments. A 300 pg/mL value for the NT-pro BNP cut-off point appears to be a sensitive level to differentiate dyspnea originating from an ailing heart or not for the patients who visited our cardiology departments.

Topographic anatomy of the inferior wall of the maxillary sinus in Koreans

Knowledge of the relationship between the root apex and the inferior wall of the maxillary sinus are crucial for diagnosing and treating a sinus pathosis as well as in assisting in dental implantation. Therefore, identifying the proximity between the root apex and the inferior wall of the sinus and clarifying the cortical thickness of the inferior wall of the sinus is essential for determining the topography of a spreading dental infection into the maxillary sinus. Accordingly, knowledge of the topography between the root apex and the inferior wall of maxillary sinus is important for diagnosing and planning dental implantation, endodontic procedures, and orthodontic treatment. This study was undertaken to clarify the morphological and clinical characteristics of the maxillary sinus, particularly the inferior wall of the sinus in Koreans, and to identify the relationship between the inferior wall of the maxillary sinus and the roots of the maxillary teeth. Twenty-four sides of the maxillae of hemi-sectioned Korean heads were used in this study. All specimens were decalcificated and sectioned coronally. On the sectioned specimens, 21 items were measured using an image analyzing system. The distances between the each root apex and the inferior wall of the maxillary sinus were measured. The distance from the root apex to the inferior wall of the sinus was the shortest in the second molar area and the longest in the first premolar area. The thickness of the cortical plate of the inferior wall of the maxillary sinus was thinnest in the first premolar area but it was thickest in the second premolar area. The vertical relationship between the inferior wall and the roots of the maxillary molars was classified into five types. Type I (the inferior wall of the sinus located above the level connecting the buccal and lingual root apices) dominated (54.5% in the first molar area, 52.4% in the second molar area). The horizontal relationship between the inferior wall of the sinus and the root apex was classified into three types. Type 2 (the alveolar recess of the inferior wall of the sinus was located between the buccal and lingual roots) was most common (80% in the first and second molar area). Overall, this study demonstrated the many anatomical characteristics and determined the relationships between the maxillary sinus and their surrounding structures. These findings may have an impact on the clinical management of patients.

Patterns of failure in gastric carcinoma after D2 gastrectomy and chemoradiotherapy: a radiation oncologist's view

The risk of locoregional recurrence in resected gastric adenocarcinoma is high, but the benefit of adjuvant treatment remains controversial. In particular, after extended lymph node dissection, the role of radiotherapy is questionable. Since 1995, we started a clinical protocol of adjuvant chemoradiotherapy after D2 gastrectomy and analysed the patterns of failure for 291 patients. Adjuvant chemotherapy consisted of five cycles of fluorouracil and leucovorin, and concurrent radiotherapy was given with 4500 cGy from the second cycle of chemotherapy. With a median follow-up of 48 months, 114 patients (39%) showed any type of failure, and the local and regional failures were seen in 7% (20 out of 291) and 12% (35 out of 291), respectively. When the recurrent site was analysed with respect to the radiation field, in-field recurrence was 16% and represented 35% of all recurrences. Our results suggest that adjuvant chemoradiotherapy has a potential effect on reducing locoregional recurrence. Moreover, low locoregional recurrence rates could give a clue as to which subset of patients could be helped by radiotherapy after D2 gastrectomy. However, in order to draw a conclusion on the role of adjuvant radiotherapy, a randomised study is needed.

Hypermethylation of the hTERT promoter inhibits the expression of telomerase activity in normal oral fibroblasts and senescent normal oral keratinocytes

Telomerase activity in human cells closely correlates with the expression of its catalytic subunit, telomerase reverse transcriptase (hTERT). Previously, we reported the lack of telomerase activity in normal human oral fibroblasts (NHOF) and the diminution of telomerase activity during senescence in normal human oral keratinocytes (NHOK). To investigate the underlying mechanisms of telomerase regulation in both cell types, we analysed the expression, promoter activity, and methylation status of the hTERT gene. The expression of hTERT mRNA diminished in senescent NHOK, but was not detected in NHOF at any stage of replication. An exogenous hTERT promoter was active in NHOF and in senescing NHOK, indicating that the lack of hTERT gene expression resulted from alteration of the endogenous hTERT promoter. Since methylation is involved in the silencing of numerous genes, we carried out DNA methylation assays. The assay revealed that the hTERT promoter was hypermethylated in NHOF and was gradually methylated during senescence in NHOK. Treatment of NHOF and senescent NHOK with the demethylating agent 5-aza-2′-deoxycytidine restored the expression of endogenous hTERT mRNA. Our results suggest that hypermethylation of the hTERT promoter plays a critical role in the negative regulation of telomerase activity in normal human oral cells.