Evaluation of the cardiotoxicity potential of bisphenol analogues in human induced pluripotent stem cells derived cardiomyocytes.

The importance of evaluating the cardiotoxicity potential of common chemicals as well as new drugs is increasing as a result of the development of animal alternative test methods using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Bisphenol A (BPA), which is used as a main material in plastics, is known as an endocrine-disrupting chemical, and recently reported to cause cardiotoxicity through inhibition of ion channels in CMs even with acute exposure. Accordingly, the need for the development of alternatives to BPA has been highlighted, and structural analogues including bisphenol AF, C, E, F, and S have been developed. However, cardiotoxicity data for analogues of bisphenol are not well known. In this study, in order to evaluate the cardiotoxicity potential of analogues, including BPA, a survival test of hiPSC-CMs and a dual-cardiotoxicity evaluation based on a multi-electrode array were performed. Acute exposure to all bisphenol analogues did not affect survival rate, but spike amplitude, beat period, and field potential duration were decreased in a dose-dependent manner in most of the bisphenols except bisphenol S. In addition, bisphenols, except for bisphenol S, reduced the contractile force of hiPSC-CMs and resulted in beating arrest at high doses. Taken together, it can be suggested that the developed bisphenol analogues could cause cardiotoxicity even with acute exposure, and it is considered that the application of the MEA-based dual-cardiotoxicity evaluation method can be an effective help in the development of safe alternatives.

Randomized Controlled Trial: Subcutaneous vs Intravenous Infliximab CT-P13 Maintenance in Inflammatory Bowel Disease.

BACKGROUND & AIMS: This study compared pharmacokinetics, symptomatic and endoscopic efficacy, safety, and immunogenicity of a subcutaneous formulation of the infliximab biosimilar CT-P13 (CT-P13 SC) vs intravenous CT-P13 (CT-P13 IV) in patients with inflammatory bowel disease (IBD). METHODS: This randomized, multicenter, open-label, parallel-group, phase 1 study enrolled tumor necrosis factor inhibitor-naïve patients with active ulcerative colitis (total Mayo score 6-12 points with endoscopic subscore ≥2) or Crohn's disease (Crohn's Disease Activity Index 220-450 points) at 50 centers. After CT-P13 IV induction at Week (W) 0/W2, patients were randomized (1:1) to receive CT-P13 SC every 2 weeks (q2w) from W6 to W54 or CT-P13 IV every 8 weeks from W6 to W22. At W30, all patients receiving CT-P13 IV switched to CT-P13 SC q2w until W54. The primary endpoint was noninferiority of CT-P13 SC to CT-P13 IV for observed predose CT-P13 concentration at W22 (Ctrough,W22), concluded if the lower bound of the 2-sided 90% confidence interval (CI) for the ratio of geometric least-squares means exceeded 80%. RESULTS: Overall, 66 and 65 patients were randomized to CT-P13 SC and CT-P13 IV, respectively. The primary endpoint of noninferiority was met with a geometric least-squares means ratio for Ctrough,W22 of 1154.17% (90% CI 786.37-1694.00; n = 59 [CT-P13 SC]; n = 57 [CT-P13 IV]). W30/W54 clinical remission rates were comparable between arms. Other efficacy, safety, and immunogenicity assessments were also broadly comparable between arms, including after switching. CONCLUSIONS: The pharmacokinetic noninferiority of CT-P13 SC to CT-P13 IV, and the comparable efficacy, safety, and immunogenicity profiles, support the potential suitability of CT-P13 SC treatment in IBD. ClinicalTrials.gov ID: NCT02883452.

Effect of Radiocephalic Anastomotic Length on the Maturation of Arteriovenous Fistula.

BACKGROUND: A radiocephalic arteriovenous fistula (RCAVF) is associated with better long-term patency and fewer complications. However, RCAVF have lower maturation rate for hemodialysis compared with upper AVF or arteriovenous graft. We performed this study to determine the effect of the radiocephalic (RC) anastomotic length on the AVF maturation. METHODS: We reviewed the patients who underwent RCAVF creation with a side-to-end manner from March 2015 to December 2018. AVF maturation was defined as successful hemodialysis (HD) in at least two consecutive sessions. We compared the possible factors including the RC anastomotic length between the initial HD success group and initial HD failure group. RESULTS: A total of 114 patients underwent RCAVF creation: 72 males and 42 females (63.2% and 36.8%, respectively). The mean preoperative arteriotomy length of the AVF was 14.1 mm (range 11.0-16.0 mm). Out of 114 patients, initial HD was executed successfully in 83 patients (72.8%). Among the 31 patients with initial HD failure (27.2%) balloon angioplasty was successfully performed in 17 patients, failed in 4 patients, and not performed in 10 patients. The secondary success rate after balloon angioplasty was 87.7%. After factor analysis, pre-emptive AVF (P = 0.01), vein diameter (P < 0.001), and flow rate (P < 0.001) were revealed significant factors for initial HD success, but not RC anastomotic length of AVF (P = 0.55). CONCLUSION: The length of the radiocephalic anastomosis does not affect the RCAVF maturation rate statistically. However, lengthening of arteriotomy on the radial artery may increase the initial success rate of HD.

Exposure Levels and Contributing Factors of Various Arsenic Species and Their Health Effects on Korean Adults.

Arsenic is a human carcinogen. Data on urinary arsenic species analyses of Koreans are limited. This study evaluated the arsenic exposure level, contributing factors, and health effects in Korean adults. Dietary intake information and urine samples were obtained from 2044 participants. Arsenic exposure was assessed based on urinary concentrations of arsenic species, such as inorganic arsenic, As(III) and As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AsB), using high-performance liquid chromatography with inductively coupled plasma mass spectrometry, followed by determination of biomarkers, malondialdehyde and c-peptide. The geometric mean concentrations were 30.9 µg/L for the sum of inorganic arsenic and their metabolites, and 84.7 µg/L for the total sum of arsenic measured. Urinary concentrations of arsenic species were influenced by age, inhabitant area (inland or coastal), and seafood intake, which was positively correlated with inorganic arsenic, DMA, and AsB. Rice intake was positively correlated with inorganic arsenic and its metabolites but not with AsB. Additionally, malondialdehyde and c-peptide levels were significantly associated with urinary concentrations of various arsenic species. Seafood and rice are major sources of organic/inorganic arsenic exposure in Korean adults; however, it is necessary to evaluate whether their overconsumption could have a potentially detrimental effect on human health.

Development and validation of dual-cardiotoxicity evaluation method based on analysis of field potential and contractile force of human iPSC-derived cardiomyocytes / multielectrode assay platform.

A recent in vitro cardiovascular safety pharmacology test uses cardiomyocytes derived from human induced pluripotent stem cells (hiPSCs) to overcome the limitations of the classical test systems, such as species differences and local channel analysis. The Comprehensive in vitro Proarrhythmia Assay (CiPA) is a new proarrhythmia screening paradigm proposed by a CiPA steering expert group, which essentially requires iPSCs derived cardiomyocyte-based electrophysiological evaluation technology. Moreover, the measurement of the contractile force is also emerging as an important parameter to recapitulate non-proarrhythmic cardiotoxicity. Therefore, we constructed an multielectrode assay (MEA) evaluation method that can measure the electrophysiological changes with 6 reference drugs in hiPSC-derived cardiomyocytes. Subsequently, it was confirmed that the electrophysiological were changed in accordance with the mechanism of action of the drugs. Furthermore, based on the multi-probe impedance, we confirmed the decrease in contractile force due to treatment with drugs, and developed a platform to evaluate cardiotoxicity according to drugs along with field potential changes. Our excitation-contraction coupling cardiotoxicity assessment is considered to be more supportive in cardiac safety studies on pharmacologic sensitivity by complementing each assessment parameter.

Efficacy, pharmacokinetics and safety of subcutaneous versus intravenous CT-P13 in rheumatoid arthritis: a randomized phase I/III trial.

OBJECTIVE: To assess non-inferiority of s.c. to i.v. CT-P13 in RA. METHODS: Patients with active RA and inadequate response to MTX participated in this phase I/III double-blind study at 76 sites. Patients received CT-P13 i.v. 3 mg/kg [week (W) 0 and W2] before randomization (1:1) at W6 to CT-P13 s.c. via pre-filled syringe (PFS) 120 mg biweekly until W28, or CT-P13 i.v. 3 mg/kg every 8 weeks until W22. Randomization was stratified by country, W2 serum CRP and W6 body weight. From W30, all patients received CT-P13 s.c. In a usability sub-study, patients received CT-P13 s.c. via auto-injector (W46-54) then PFS (W56-64). The primary endpoint was change (decrease) from baseline in disease activity score in 28 joints (DAS28)-CRP at W22 (non-inferiority margin: -0.6). RESULTS: Of 357 patients enrolled, 343 were randomized to CT-P13 s.c. (n = 167) or CT-P13 i.v. (n = 176) at W6. The least-squares mean change (decrease) from baseline (standard error) in DAS28-CRP at W22 was 2.21 (0.22) for CT-P13 s.c. (n = 162) and 1.94 (0.21) for CT-P13 i.v. [n = 168; difference 0.27 (95% CI: 0.02, 0.52)], establishing non-inferiority. Efficacy findings were similar between arms at W54. Safety was similar between arms throughout: 92 (54.8%; CT-P13 s.c.) and 117 (66.9%; CT-P13 i.v.) patients experienced treatment-emergent adverse events (from W6). There were no treatment-related deaths or new safety findings. Usability was similar for CT-P13 s.c. via auto-injector or PFS. CONCLUSION: CT-P13 s.c. was non-inferior to CT-P13 i.v. in active RA. The convenience of s.c. administration could benefit patients. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT03147248.

Lucanthone, Autophagy Inhibitor, Enhances the Apoptotic Effects of TRAIL through miR-216a-5p-Mediated DR5 Upregulation and DUB3-Mediated Mcl-1 Downregulation.

A lucanthone, one of the family of thioxanthenones, has been reported for its inhibitory effects of apurinic endonuclease-1 and autophagy. In this study, we investigated whether lucanthone could enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in various cancer cells. Combined treatment with lucanthone and TRAIL significantly induced apoptosis in human renal carcinoma (Caki and ACHN), prostate carcinoma (PC3), and lung carcinoma (A549) cells. However, combined treatment did not induce apoptosis in normal mouse kidney cells (TCMK-1) and normal human skin fibroblast (HSF). Lucanthone downregulated protein expression of deubiquitinase DUB3, and a decreased expression level of DUB3 markedly led to enhance TRAIL-induced apoptosis. Ectopic expression of DUB3 inhibited combined treatment with lucanthone and TRAIL-induced apoptosis. Moreover, lucanthone increased expression level of DR5 mRNA via downregulation of miR-216a-5p. Transfection of miR-216a-5p mimics suppressed the lucanthone-induced DR5 upregulation. Taken together, these results provide the first evidence that lucanthone enhances TRAIL-induced apoptosis through DR5 upregulation by downregulation of miR-216a-5p and DUB3-dependent Mcl-1 downregulation in human renal carcinoma cells.

Farrerol Induces Cancer Cell Death via ERK Activation in SKOV3 Cells and Attenuates TNF-α-Mediated Lipolysis.

Farrerol (FA) is a flavanone isolated from the Chinese herbal medicine "Man-shan-hong" (Rhododendron dauricum L.). In the present study, FA decreased the viability of SKOV3 cells in a dose- and time-dependent manner, and it induced G2/M cell cycle arrest and cell apoptosis. Cell cycle distribution analysis via flow cytometry showed that FA decreased G1 populations and increased G2/M populations in SKOV3 cells. Additionally, Western blotting confirmed an increase in the expression level of proteins involved in the cell cycle, e.g., CDK and cyclins. FA-induced apoptosis in SKOV3 cells was also investigated using a TUNEL assay, and increased expression levels of proapoptotic factors, including Caspase-3 and poly ADP ribose polymerase (PARP), through the Extracellular signal-regulated kinase (ERK)/MAPK pathway were investigated. Proinflammatory cytokines (e.g., IL-6, TNF-α, and IL-1) have been identified as a driver of the pathological mechanisms underlying involuntary weight loss and impaired physical function, i.e., cachexia, during cancer; in the present study, we showed that farrerol attenuates TNF-α-induced lipolysis and increases adipogenic differentiation in 3T3-L1 cells. Thus, farrerol could potentially be used as an anticancer agent or anticachetic drug.

Vitrification for cryopreservation of 2D and 3D stem cells culture using high concentration of cryoprotective agents.

BACKGROUND: Vitrification is the most promising technology for successful cryopreservation of living organisms without ice crystal formation. However, high concentrations (up to ~ 6-8 M) of cryoprotective agents (CPAs) used in stem cell induce osmotic and metabolic injuries. Moreover, the application of conventional slow-freezing methods to cultures of 3-D organoids of stem cells in various studies, is limited by their size. RESULTS: In this study, we evaluated the effect of high concentrations of CPAs including cytotoxicity and characterized human mesenchymal stem cell (MSC) at single cell level. The cell viability, cellular damage, and apoptotic mechanisms as well as the proliferation capacity and multipotency of cells subjected to vitrification were similar to those in the slow-freezing group. Furthermore, we identified the possibility of vitrification of size-controlled 3-D spheroids for cryopreservation of organoid with high survivability. CONCLUSIONS: Our results demonstrate successful vitrification of both single cell and spheroid using high concentration of CPAs in vitro without cytotoxicity.

A Subset of Paracrine Factors as Efficient Biomarkers for Predicting Vascular Regenerative Efficacy of Mesenchymal Stromal/Stem Cells.

Mesenchymal stromal/stem cells (MSCs) have been developed as a promising source for cell-based therapies of ischemic disease. However, there are some hurdles in their clinical application such as poor cell engraftment and inconsistent stem cell potency. In this study, we sought to find biomarkers for predicting potency of MSCs for proangiogenic therapy to improve their beneficial effects. Large variations were observed in proangiogenic factor secretion profiles of conditioned media derived from nine different donor-derived Wharton's jelly (WJ)-derived MSCs and 8 factors among 55 angiogenesis-related factors were secreted at considerable levels. Two distinct WJ-MSCs that had the lowest or the highest secretion of these eight factors showed corresponding proangiogenic activities in in vitro angiogenesis assays. When four additional different donor-derived WJ-MSCs were further examined, proangiogenic activities in migration and tube formation of endothelial cells and in in vivo Matrigel plug assay were highly consistent with secretion levels of four major factors (angiogenin, interleukin-8, monocyte chemoattractant protein-1, and vascular endothelial growth factor). Such correlation was also observed in vascular regenerative effect in a mouse hind limb ischemia model. Blocking of these four factors by neutralizing antibodies or knockdown of them by siRNA treatment resulted in significant inhibition of proangiogenic activities of not only WJ-MSCs, but also bone marrow-derived MSCs. These results suggest that these four factors may represent efficient biomarkers for predicting vascular regenerative efficacy of MSCs. Stem Cells 2019;37:77-88.

Functional Equivalency in Human Somatic Cell Nuclear Transfer-Derived Endothelial Cells.

The derivation of human embryonic stem cells (hESCs) by somatic cell nuclear transfer (SCNT) has prompted a re-emerging interest in using such cells for therapeutic cloning. Despite recent advancements in derivation protocols, the functional potential of CHA-NT4 derived cells is yet to be elucidated. For this reason, this study sought to differentiate CHA-NT4 cells toward an endothelial lineage in order to evaluate in vitro and in vivo functionality. To initial differentiation, embryoid body formation of CHA-NT4 was mediated by concave microwell system which was optimized for hESC-endothelial cell (EC) differentiation. The isolated CD31+ cells exhibited hallmark endothelial characteristics in terms of morphology, tubule formation, and ac-LDL uptake. Furthermore, CHA-NT4-derived EC (human nuclear transfer [hNT]-ESC-EC) transplantation in hind limb ischemic mice rescued the hind limb and restored blood perfusion. These findings suggest that hNT-ESC-EC are functionally equivalent to hESC-ECs, warranting further study of CHA-NT4 derivatives in comparison to other well established pluripotent stem cell lines. This revival of human SCNT-ESC research may lead to interesting insights into cellular behavior in relation to donor profile, mitochondrial DNA, and oocyte quality. Stem Cells 2019;37:623-630.

Therapeutic Effect of Seaweed Derived Xanthophyl Carotenoid on Obesity Management; Overview of the Last Decade.

Present-day lifestyles associated with high calorie-fat intake and accumulation, as well as energy imbalance, have led to the development of obesity and its comorbidities, which have emerged as some of the major health issues globally. To combat the disease, many studies have reported the anti-obesity effects of natural compounds in foods, with some advantages over chemical treatments. Carotenoids, such as xanthophyll derived from seaweeds, have attracted the attention of researchers due to their notable biological activities, which are associated mainly with their antioxidant properties. Their involvement in oxidative stress modulation, the regulation of major transcription factors and enzymes, and their antagonistic effects on various obesity parameters have been examined in both in vitro and in vivo studies. The present review is a collation of published research over the last decade on the antioxidant properties of seaweed xanthophyll carotenoids, with a focus on fucoxanthin and astaxanthin and their mechanisms of action in obesity prevention and treatment.

Sargassum miyabei Yendo Brown Algae Exert Anti-Oxidative and Anti-AdipogenicEffects on 3T3-L1 Adipocytes by Downregulating PPARγ.

Background and objectives: Sargassum miyabei Yendo, belonging to the family Sargassaceae, has been reported to have various biological effects such as anti-tyrosinase activity and anti-inflammation. However, the anti-obesity effect of Sargassum miyabei Yendo has not yet been reported. Materials and Methods: The effects of Sargassum miyabei Yendo extract (SME) on 3T3-L1 adipocytes were screened by3-(4,5)-dimethylthiazo-2-yl-2,5-diphenyltetrazolium bromide (MTT), Oil red O staining, western blot, and Real-time reverse transcription polymerase chain reaction analyses. Results: Here, we show that SME had potent 2,2'-azinobis-3-ehtlbezothiazoline-6-sulfonic acid radical decolorization (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity with half maximal inhibitory concentration (IC50) value of 0.2868 ± 0.011 mg/mL and 0.2941 ± 0.014 mg/mL, respectively. In addition, SME significantly suppressed lipid accumulation and differentiation of 3T3-L1 preadipocytes, as shown by Oil Red O staining results. SME attenuated the expression of adipogenic- and lipogenic-related genes such as peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT-enhancer-binding protein alpha (C/EBPα), CCAAT-enhancer-binding protein delta (C/EBPδ), adiponectin, adipose triglyceride lipase (ATGL), fatty acid synthase (FAS), hormone-sensitive lipase (HSL), and lipoprotein lipase (LPL). Conclusions: These findings suggest that SME may have therapeutic implications for developing a new anti-obesity agent.

Selective Self-Assembly of a Rectangular Ruthenium Supramolecule from an Unsymmetrical Bridging Unit.

Herein, we report the synthesis of an unsymmetrical diruthenium bridging unit containing a multidentate oxamate ligand and the subsequent formation of a rectangular supramolecule. The reaction of oxamate 1, 2-((4-bromo-2,6-dimethylphenyl)amino)-2-oxo-acetic acid, and [(p-cymene)RuCl2]2 affords a novel unsymmetrical diruthenium acceptor clip 2, where two ruthenium metal centers are ligated with either [O,O] or [N,O]. The molecular clip 2 and bipyridine donor self-assemble to form two-dimensional rectangular supramolecule 3. Self-assembly can produce seven possible isomers depending on the position of the substituted bromoaryl groups. However, 1H NMR spectroscopic investigation indicated only two different isomers in the reaction mixture. A single isomer is isolated via crystallization, and X-ray crystallography confirms that the product is a C1 symmetric two-dimensional rectangular supramolecule, in which two bromoaryl groups are located in the farthest position from each other. Theoretical calculations suggest that the self-assembly of supramolecule 3 occurred via 1:1 adducts of the diruthenium molecular clip and bipyridine as an intermediate to predominantly form a single isomer.

Beneficial Effects of Natural Bioactive Compounds from Hibiscus sabdariffa L. on Obesity.

Obesity is a condition associated with the accumulation of excess fat in the body, energy imbalance, lipogenesis, etc., which increases adipose tissue mass through adipogenesis and poses a health risk. Its prevalence has become an economic burden to the health care system and the world at large. One of the alternatives to tackling obesity involves the use of bioactive compounds. We critically examined the effects of Hibiscus sabdariffa extract (HSE) on various parameters associated with the development of obesity such as; the effect of HSE on body weight, the effect of HSE on lipid accumulation, cholesterol metabolism and plasma parameters, the inhibitory effect of HSE on pancreatic lipase, and the effect of HSE on adipocyte differentiation/adipogenesis. This review has gathered reports on the various anti-obesity effects of H. sabdariffa bioactive compounds in cell and animal models, as well as in humans. Available toxicology information on the consumption of H. sabdariffa revealed that its toxicity is dose-dependent and may cause an adverse effect when administered over a long period of time. Reports have shown that H. sabdariffa derived bioactive compounds are potent in the treatment of obesity with an evident reduction in body weight, inhibition of lipid accumulation and suppression of adipogenesis through the PPARγ pathway and other transcriptional factors.

Autophagy mediates enhancement of proangiogenic activity by hypoxia in mesenchymal stromal/stem cells.

Mesenchymal stromal/stem cells (MSCs) have been promising source for regenerative cell therapy in ischemic diseases. To improve efficacy of MSC therapy, various priming methods have been developed, and hypoxic priming has been reported to enhance therapeutic efficacy of MSCs by increasing secretion level of growth factors and cytokines. Recently, it has been reported that bone marrow MSCs primed with hypoxic condition show an increase of autophagy. Here, we addressed whether proangiogenic activity increased by hypoxic condition is associated with autophagy. Wharton's jelly derived MSCs primed with hypoxia showed increase of autophagy with increased hypoxia inducible factor-1α level, and conditioned medium (CM) derived from these cells showed increased levels of migration and tube formation of human umbilical vein endothelial cells (HUVECs) compared to non-primed MSCs-derived CM. Pretreatment with autophagy inhibitor 3-methyladenine or chloroquine prior to exposure of hypoxia resulted in reduction of migration and tube formation of HUVECs. CM obtained under hypoxic condition from MSCs in which autophagy activity was inhibited by ATG5 and ATG7 siRNA treatment also showed decrease of migration and tube formation of HUVECs. Accordingly, secretion levels of angiogenin and VEGF that were markedly increased upon hypoxia exposure was decreased by ATG5/7 knockdown. Therefore, it may be suggested that autophagy plays an important role in hypoxia-driven enhancement of paracrine effect of MSCs.

Salinomycin ameliorates oxidative hepatic damage through AMP-activated protein kinase, facilitating autophagy.

Salinomycin, a monocarboxylic ionophore in Streptomyces albus, has been studied as an anti-cancer agent. However, we wondered whether salinomycin has another effect such as an anti-oxidant and hepatic protectant, because some chemical drugs treating human diseases were sometimes related with their toxic effects. Therefore, this study was conducted to examine the effects of salinomycin against oxidative stress and mitochondrial impairment in vivo and in vitro as well as the cellular mechanisms of action. In hepatocyte, salinomycin inhibited arachidonic acid (AA) + iron-induced apoptosis, mitochondrial dysfunction and ROS production. As a molecular mechanism, salinomycin induced autophagy through AMP-activated protein kinase (AMPK) activation, as assessed by the accumulation of acidic vesicle organelles, p62 and LC3-II. Moreover, these protective effects were blocked by AMPK inhibition, which indicates the importance of AMPK in the process of salinomycin's effects. In mice, oral administration of salinomycin protected against carbon tetrachloride (CCl4)-induced oxidative stress and liver injury, and also activated AMPK as well as autophagy-related proteins in the liver. Collectively, salinomycin had the ability to protect hepatocytes against AA+iron-induced reactive oxygen species production and mitochondrial dysfunction, as well as CCl4-induced liver injury. Although this beneficial effect was demonstrated under severe oxidative stress, this study showed that salinomycin protected the liver against the oxidative stress and liver damage through AMPK and autophagy, and suggest that salinomycin has a possibility to treat a broad range of diseases.

Tetra-, Hexa-, Dodeca-Nuclear Ir Supramolecules via Bridge-Driven Self-Assembly of Tetrazolyl Ligands.

Herein, we report the formation of multinuclear Ir4, Ir6, and Ir12 supramolecular complexes via the bridge-driven self-assembly of tetrazolyl ligands. The synthesis of dimeric half-sandwich Ir units was made by the reaction of half-sandwich Ir units and tetrazolyl ligands in a molar ratio of 1:2. The use of different ligands containing multiple tetrazolyl units resulted in the formation of different Ir supramolecular architectures. The reaction of [Cp*IrCl2]2, AgOTf, and 1,2- or 1,3-ditetrazolyl benzene in a molar ratio of 1:3:1 resulted in the formation of rectangular tetranuclear or truncated trigonal pyramidal hexanuclear Ir complexes, respectively. On the other hand, the reaction of [Cp*IrCl2]2, AgOTf, and 1,3,5-tritetrazolyl benzene in a molar ratio of 6:18:4 produced a supramolecular dodecanuclear iridium complex. The molecular structure of the complex resembled a truncated tetrahedral structure with a large inner cavity, as determined by X-ray crystallography.

Endo- and Exocyclic Coordination of a 20-Membered N2O2S2-Macrocycle and Cascade Complexation of a 40-Membered N4O4S4-Macrocycle.

A 20-membered N2O2S2-macrocycle (L1) and a 40-membered N4O4S4-macrocycle (L2) were employed as a [1:1] and a [2:2] cyclization product, respectively, for the preparation of diverse types of supramolecular complexes including a cascade complex. Six complexes (1-6) of the smaller macrocycle L1 including discrete to continuous forms, mono- to heteronuclear, and endo- to exo- and endo/exocoordination were prepared and their coordination modes were discussed systemically. First, the reaction of L1 with CuI in the presence of trifluoroacetic acid afforded an exocyclic 1-D coordination polymer {[(µ4-Cu4I4)(HL1)2](CF3COO)2} n (1). Meanwhile, the reaction of L1 with Cu(ClO4)2·6H2O afforded a typical endocyclic mononuclear complex [CuII(L1)](ClO4)2·H2O (2). In the reactions of L1 with CdX2 (X = Br and I), isostructural sandwich-type complexes [Cd(L1)2Br2] (3) and [Cd(L1)2I2] (4) were isolated. The treatment of L1 with Hg(ClO4)2 also afforded a sandwich-type complex [Hg(L1)2](ClO4)2 (5). One-pot reaction of L1 with a mixture of HgI2 and CdI2 afforded a dumbbell-type heteronuclear complex {[Cd(L1)]2(µ-Hg2I6)}[Hg2I6] (6), in which the Cd(II) ion occupies the macrocyclic cavity. Further, such two endocyclic Cd(II) complex units are bridged by a square-type (µ-Hg2I6)2- cluster remaining another same cluster separately. The comparative NMR data exhibited a higher affinity of Cd(II) over Hg(II) toward L1, in the parallel to the situation occurred in the solid state. Meanwhile, complexations of the extra-large macrocycle L2 is more challenging to afford some interesting dimercury(II) coordination products including a cascade complex. In solution, the dimercury(II) perchlorato complex of L2 as a metalloligand shows a preferential binding of dabco (1,4-diazabicyclo[2,2,2]octane), but its dimercury(II) iodo complex has a much smaller affinity for dabco. In order to explain these results, the solid dimercury(II) complexes with different anions [Hg2(L2)X4] (7: X = I, 8: X = ClO4) were prepared and characterized. Further, the dimercury(II) perchlorato complex 8 reacts with dabco to forms a cascade complex [Hg2(L2)(µ-dabco)(ClO4)2](ClO4)2·2DMF·2ether (9), exhibiting its formation being metal-driven and coordinated anion-regulated. The observed cascade complexation both in solution and solid states is an example of the adaptive guest binding.

Yonsei Experience of 5000 Gasless Transaxillary Robotic Thyroidectomies.

BACKGROUND: Since the use of robot systems in thyroid surgery was introduced in 2007, we have advanced a novel method of robotic thyroidectomy (RT) using a gasless transaxillary approach (TAA). We report our experience with this technique and detail the surgical outcome of 5000 robotic thyroidectomies. METHODS: From October 2007 to May 2016, we successfully performed 5000 robotic thyroidectomies using a gasless TAA at the Department of Surgery, Yonsei University Health System. The medical records of the patients are reviewed retrospectively, and the details of clinicopathologic characteristics, operation times, perioperative complications, and oncologic outcomes are analyzed. RESULTS: The 5000 patients with thyroid tumor (4804 with cancer and 196 with benign tumor) underwent RT using a gasless TAA. Mean operation time was 134.5 ± 122.0 min. The most common histologic subtype of thyroid cancer was papillary (98%), and the mean tumor size was 8.0 ± 6.0 mm. Stage I was found in 85.4% patients regarding tumor nodes metastasis staging. The 196 benign tumors consisted of 104 adenomatous hyperplasias (53.0%), 43 follicular adenomas (21.9%), 30 Graves' diseases (15.3%), and 19 others (9.7%). Postoperative complication occurred in 24.1% without any serious one, and overall morbidity tended to decrease over time. No disease-specific mortality was observed during the follow-up period. Locoregional recurrence was developed in 26 patients (0.5%). CONCLUSION: The authors have tried to improve RT technique using gasless TAA and achieved acceptable surgical outcomes. The rapid evolution of surgical robot technology and our constant effort to advance RT technique using gasless TAA would make it possible to reduce the perioperative morbidity and gain the best possible operative and oncologic outcomes.