Production of H2 and Glucaric Acid Using Electrocatalyst Glucose Oxidation by the Ta NiFe LDH Electrode

The slow anodic oxygen evolution reaction (OER) significantly limits electrocatalytic water splitting for hydrogen production. We proposed the electrocatalyst for glucose oxidation by Ta-doping NiFe LDH nanosheets to simultaneously obtain glucaric acid (GRA) and hydrogen gas as a useful byproduct. Superior glucose oxidation reaction (GOR) activity is demonstrated by the optimized Ta-NiFe LDH, which has a low overpotential of 192 mV, allowing for a small Tafel slope of 70 mV dec-1 and a current density of 50 mA cm-2. The Ta NiFe LDH-oxidized glucose to GRA with a 72.94% yield and 64.3% Faradaic efficiency at 1.45 VRHE. Herein, we report the Ta NiFe LDH/NF electrode for the GOR&hydrogen evolution reaction (HER), which exhibits a cell voltage of 1.62 V to reach a current density of 10 mA cm-2, which is 250 mV lower compared to OER&HER (1.87 V). This study reveals that GOR is an energy-efficient and cost-effective method for producing H2 and valorizing biomass.

A systematic review on green and natural polymeric nanofibers for biomedical applications

Electrospinning is the simplest technique to produce ultrathin nanofibers, which enables the use of nanotechnology in various applications. Nanofibrous materials produced through electrospinning have garnered significant attention in biomedical applications due to their unique properties and versatile potential. In recent years, there has been a growing emphasis on incorporating sustainability principles into material design and production. However, electrospun nanofibers, owing to their reliance on solvents associated with significant drawbacks like toxicity, flammability, and disposal challenges, frequently fall short of meeting environmentally friendly standards. Due to the limited solvent choices and heightened concerns for safety and hygiene in modern living, it becomes imperative to carefully assess the implications of employing electrospun nanofibers in diverse applications and consumer products. This systematic review aims to comprehensively assess the current state of research and development in the field of "green and natural" electrospun polymer nanofibers as well as more fascinating and eco-friendly commercial techniques, solvent preferences, and other green routes that respect social and legal restrictions tailored for biomedical applications. We explore the utilization of biocompatible and biodegradable polymers sourced from renewable feedstocks, eco-friendly processing techniques, and the evaluation of environmental impacts. Our review highlights the potential of green and natural electrospun nanofibers to address sustainability concerns while meeting the demanding requirements of various biomedical applications, including tissue engineering, drug delivery, wound healing, and diagnostic platforms. We analyze the advantages, challenges, and future prospects of these materials, offering insights into the evolving landscape of environmentally responsible nanofiber technology in the biomedical field.

Electrocatalytic Reactions for Converting CO2 to Value-Added Products: Recent Progress and Emerging Trends

Carbon dioxide (CO₂) emissions are an important environmental issue that causes greenhouse and climate change effects on the earth. Nowadays, CO₂ has various conversion methods to be a potential carbon resource, such as photocatalytic, electrocatalytic, and photo-electrocatalytic. CO₂ conversion into value-added products has many advantages, including facile control of the reaction rate by adjusting the applied voltage and minimal environmental pollution. The development of efficient electrocatalysts and improving their viability with appropriate reactor designs is essential for the commercialization of this environmentally friendly method. In addition, microbial electrosynthesis which utilizes an electroactive bio-film electrode as a catalyst can be considered as another option to reduce CO₂. This review highlights the methods which can contribute to the increase in efficiency of carbon dioxide reduction (CO₂R) processes through electrode structure with the introduction of various electrolytes such as ionic liquid, sulfate, and bicarbonate electrolytes, with the control of pH and with the control of the operating pressure and temperature of the electrolyzer. It also presents the research status, a fundamental understanding of carbon dioxide reduction reaction (CO₂RR) mechanisms, the development of electrochemical CO₂R technologies, and challenges and opportunities for future research.

Photoelectrochemical Epoxidation of Cyclohexene on an α-Fe2O3 Photoanode Using Water as the Oxygen Source

This study developed a safe and sustainable route for the epoxidation of cyclohexene using water as the source of oxygen at room temperature and ambient pressure. Here, we optimized the cyclohexene concentration, volume of solvent/water (CH₃CN, H₂O), time, and potential on the photoelectrochemical (PEC) cyclohexene oxidation reaction of the α-Fe₂O₃ photoanode. The α-Fe₂O₃ photoanode epoxidized cyclohexene to cyclohexene oxide with a 72.4 ± 3.6% yield and a 35.2 ± 1.6% Faradaic efficiency of 0.37 V vs Fc/Fc⁺ (0.8 V_Ag/AgCl) under 100 mW cm^-2. Furthermore, the irradiation of light (PEC) decreased the applied voltage of the electrochemical cell oxidation process by 0.47 V. This work supplies an energy-saving and environment-benign approach for producing value-added chemicals coupled with solar fuel generation. Epoxidation with green solvents via PEC methods has a high potential for different oxidation reactions of value-added and fine chemicals.

Photoelectrochemical Performance of a CuBi2O4 Photocathode with H2O2 as a Scavenger

Photoelectrochemical (PEC) water splitting is an eco-friendly method for producing clean and sustainable hydrogen fuels. Compared with the fabrication of solar hydrogen using n-type metal oxide semiconductor photoanodes, that of solar hydrogen using p-type metal oxide semiconductor photocathodes has not been researched as thoroughly. Therefore, this study investigated the effect of drop casting time on the PEC performance of a prepared CuBi2O4 photocathode. XPS, HRTEM, UV-DRS, Raman spectroscopy, XRD, and SEM analyses were used to characterize the prepared CuBi2O4 photocathode. Owing to the high charge separation and transfer, the photocurrent density of the CuBi2O4 photocathode was ~0.6 mA cm−2 at 0.3 V vs. RHE. The nanoporous CuBi2O4 photocathode exhibited a high photocurrent density of up to 1.2 mA cm−2 at 0.3 V vs. RHE with H2O2 as a sacrificial agent. Mott–Schottky and impedance measurements were also performed on the CuBi2O4 photocathode to estimate its acceptor density and charge-transfer resistance.

Development of Low-Shrink Epoxy Putty to Solve Appearance-Quality Defects of Carbon-Fiber-Reinforced Plastic Automotive Exterior Parts

In this study, epoxy putties with novel compositions were developed for the filling of structural voids in carbon-fiber-reinforced plastics (CFRPs), which are used to fabricate automotive parts. Two constituent solutions—one consisting of epoxy resins and the other consisting of a hardener—were formulated, mixed, and then coated on CFRP surfaces, followed by curing. The surfaces were then evaluated to determine the shrinkage rates (calculated based on the liquid densities and cured mixtures), adhesion properties (determined by a peel test), and color differences (measured with a colorimeter) of the synthesized putties. The last two properties were compared with those of the commercially available putties to ascertain the thermal resistance of the developed putties. The results indicated that the synthesized epoxy putties were more strongly adhesive and exhibited less difference in color. Furthermore, after thermal impact, both the adhesive properties and color stabilities of the synthesized epoxy putties were found to be superior to those of the commercial putty.

Potential application of immunotherapy for modulation of pulp inflammation: opportunities for vital pulp treatment

Caries results in the demineralization and destruction of enamel and dentine, and as the disease progresses, irreversible pulpitis can occur. Vital pulp therapy (VPT) is directed towards pulp preservation and the prevention of the progression of inflammation. The outcomes of VPT are not always predictable, and there is often a poor correlation between clinical signs and symptoms, and the events occurring at a molecular level. The inflamed pulp expresses increased levels of cytokines, including tumour necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-4, IL-6, IL-8, IL-17 and IL-23, which recruit and drive a complex cellular immune response. Chronic inflammation and sustained cytokine release can result in irreversible pulp damage and a decreased capacity for tissue healing. Other chronic inflammatory diseases, such as psoriasis, inflammatory bowel diseases and rheumatoid arthritis, are also characterized by an dysregulated immune response composed of relatively high cytokine levels and increased numbers of immune cells along with microbial and hard-soft tissue destructive pathologies. Whilst anti-cytokine therapies have been successfully applied in the treatment of these diseases, this approach is yet to be attempted in cases of pulp inflammation. This review therefore focuses on the similarities in the aetiology between chronic inflammatory diseases and pulpitis, and explores how anti-cytokine therapies could be applied to manage an inflamed pulp and facilitate healing. Further proof-of-concept studies and clinical trials are justified to determine the effectiveness of these treatments to enable more predictable outcomes in VPT.

Redox-Initiated Reversible Addition-Fragmentation Chain Transfer (RAFT) Miniemulsion Polymerization of Styrene using PPEGMA-Based Macro-RAFT Agent

Redox-initiated reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerizations are successfully conducted with an employment of trithiocarbonate-based macro-RAFT agents and surfactant. Two macro-RAFT agents-hydrophilic poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA₂₇ ) and amphiphilic poly(poly(ethylene glycol) methyl ether methacrylate)-b-polystyrene (PPEGMA₂₇ -b-PS₃₃ )- are examined for the miniemulsion polymerization of styrene. The use of PPEGMA₂₇ (in the presence of sodium dodecyl sulfate (SDS)) results in a slow polymerization rate with a broad particle size. In the absence of SDS, the use of PPEGMA₂₇ -b-PS₃₃ results in a broad particle size distribution due to its inability to form uniform initial droplets whereas the same amphiphilic block copolymer in the presence of SDS yields resulting products with a uniform particle size distribution. The latter exhibits a fashion of controlled polymerization with a high consumption of monomer (98% in 100 min) and a narrow molecular weight distribution throughout the polymerization. This is attributed to the formation of uniform droplets facilitated by SDS in a miniemulsion. The amphiphilic macro-RAFT agent is able to anchor efficiently on the monomer droplet or particle/water interface and form stabilized particles of well-defined PPEGMA₂₇ -b-PS block copolymer, confirmed using dynamic light scattering and transmission electron micrographs.

Flame Retardant Submicron Particles via Surfactant-Free RAFT Emulsion Polymerization of Styrene Derivatives Containing Phosphorous

The reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization of diethyl-(4-vinylbenzyl) phosphate (DEVBP) was performed using PEG-TTC as a macro RAFT agent. PEG-TTC (M_W 2000, 4000) was synthesized by the esterification of poly (ethylene glycol) methyl ether with a carboxylic-terminated RAFT agent, composed a hydrophilic poly (ethylene glycol) (PEG) block and a hydrophobic dodecyl chain. The RAFT emulsion polymerization of DEVBP was well–controlled with a narrow molecular size distribution. Dynamic light scattering and confocal laser scanning microscopy were used to examine the PEG-b-PDVBP submicron particles, and the length of the PEG chain (hydrophilic block) was found to affect the particle size distribution and molecular weight distribution. The submicron particle size increased with increasing degree of polymerization (35, 65, and 130), and precipitation was observed at a high degree of polymerization (DP) using low molecular weight PEG-TTC (DP 130, A3). The flame retardant properties of the PEG-b-PDVBP were evaluated by thermogravimetric analysis (TGA) and micro cone calorimeter (MCC). In the combustion process, the residue of PEG-b-PDEVBP were above 500 °C was observed (A1 ~ B3, 27 ~ 38%), and flame retardant effect of PEG-b-PDEVBP submicron particles/PVA composite were confirmed by increasing range of temperature and decreasing total heat release with increasing contents of PEG-b-PDEVBP. The PEG-b-PDEVBP submicron particles can provide flame retardant properties to aqueous, dispersion and emulsion formed organic/polymer products.

An additional potential donor-bearing alkylidene-containing latent NHC–ruthenium-based catalyst for olefin metathesis polymerization

Introduction of an additional donor, by tethering substituted pyridine, in the alkylidene ligand of a NHC-based ruthenium complex initiates latent olefin metathesis polymerization.

Modified Epoxy Resin Synthesis from Phosphorus-Containing Polyol and Physical Changes Studies in the Synthesized Products

Epoxy resins are commonly used to manufacture the molding compounds, reinforced plastics, coatings, or adhesives required in various industries. However, the demand for new epoxy resins has increased to satisfy diverse industrial requirements such as enhanced mechanical properties, thermal stability, or electrical properties. Therefore, in this study, we synthesized new epoxy resin (PPME) by modifying phosphorous-containing polyol. The prepared resin was analyzed and added to epoxy compositions in various quantities. The compositions were cured at high temperatures to obtain plastics to further test the mechanical and thermal properties of the epoxy resin. The measured tensile and flexural strength of epoxy compositions were similar to the composition without synthesized epoxy resin. However, the heat release rates of the compositions exhibited tendencies of a decrease proportional to the amount of PPME.

Human papillomavirus and oral and oropharyngeal carcinoma: the essentials

There is a global increase in the prevalence of human papillomavirus (HPV)-driven oropharyngeal squamous cell carcinoma (OPSCC) in Australia and New Zealand. Risk factors for HPV-positive OPSCC are male gender, white race, age older than 40 but younger than 59 years old, having multiple lifetime sex partners, having oro-genital and oro-anal sex. High-risk HPV subtypes play a major role in the pathogenesis of OPSCC, however, they play a much lesser role in oral squamous cell carcinoma (OSCC). Among the laboratory tests used to detect oncogenic HPV infection, polymerase chain reaction is a sensitive method but does not reflect the role of HPV in oncogenesis. While widely used, p16 immunohistochemistry is both a sensitive and a specific surrogate marker for oncogenic HPV infection in OPSCC, but not in OSCC. However, it is a useful prognostic marker in OPSCC. The current gold standard to accurately detect oncogenic HPV infection is E6/E7 mRNAin situ hybridization. Because both HPV-positive and p16-positive OPSCC have better short-term prognoses there is current debate and trials on treatment de-escalation in HPV-positive OPSCC. Dental practitioners can play an important role in early diagnosis of HPV-positive OPSCC.

Mechanical and Thermal Properties of Epoxy Composites Containing Zirconia-Impregnated Halloysite Nanotubes with Different Loadings

Epoxy resins are widely used in various industrial fields due to their low cost, good workability, heat resistance, and good mechanical strength. However, they suffer from brittleness, an issue that must be addressed for further applications. To solve this problem, additional fillers are needed to improve the mechanical and thermal properties of the resins; zirconia is one such filler. However, it has been reported that aggregation may occur in the epoxy composites as the amount of zirconia increases, preventing enhancement of the mechanical strength of the epoxy composites. Herein, to reduce the aggregation, zirconia was well dispersed on halloysite nanotubes (HNTs), which have high thermal and mechanical strength, by a conventional wet impregnation method. The HNTs were impregnated with zirconia at different loadings using zirconyl chloride octahydrate as a precursor. The mechanical and thermal strengths of the epoxy composites with these fillers were investigated. The zirconia-impregnated HNTs (Zr/HNT) were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and tunneling electron microscopy (TEM). The hardening conditions of the epoxy composites were analyzed by differential scanning calorimetry (DSC). The thermal strength of the epoxy composites was studied by thermomechanical analysis (TMA) and micro-calorimetry and the mechanical strength of the epoxy composites (flexural strength and tensile strength) was studied by using a universal testing machine (UTM). The mechanical and thermal strengths of the epoxy composites with Zr/HNT were improved compared to those of the epoxy composite with HNT, and also increased as the zirconia loading on HNT increased.

Incidence of cephalosporin-induced anaphylaxis and clinical efficacy of screening intradermal tests with cephalosporins: A large multicenter retrospective cohort study

BACKGROUND

Few studies have investigated the incidence of anaphylaxis induced by individual or structurally similar cephalosporins. The aims of the study were to assess the incidence of cephalosporin-induced anaphylaxis and evaluate the clinical efficacy of screening skin tests.

METHODS

In this retrospective cohort study, we obtained information on total cephalosporin use and cephalosporin-induced anaphylaxis in intravenous cephalosporin recipients in 12 general hospitals between 2013 and 2015. Cephalosporins were divided into 4 groups according to similar side-chain structures. The incidence of cephalosporin-induced anaphylaxis was assessed for each cephalosporin, cephalosporin generation, and side-chain group. To verify the efficacy of screening intradermal tests (IDT) with cephalosporin, the 12 hospitals were assigned to the intervention or control group depending on whether they performed screening IDT before the administration of cephalosporins.

RESULTS

We identified 76 cases of cephalosporin-induced anaphylaxis with 1 123 345 exposures to intravenous cephalosporins (6.8 per 100 000 exposures), and the incidence of fatal anaphylaxis by cephalosporin was 0.1 cases per 100 000 exposures. The highest incidences of anaphylaxis occurred in the ceftizoxime (13.0 cases per 100 000 exposures) and side-chain group 1 (cefepime, cefotaxime, ceftizoxime, ceftriaxone, and cefuroxime; 9.3 per 100 000). There was no case of anaphylaxis induced by cefoxitin, cefmetazole, cefminox, and cefotiam. The clinical effectiveness of routine screening IDT was not significant (P = .06).

CONCLUSIONS

The incidence of cephalosporin-induced anaphylaxis differed according to individual drugs and side-chain structure. Screening IDT showed no clinical efficacy at a population level.

Synthesis of Benzene Tetracarboxamide Polyamine and Its Effect on Epoxy Resin Properties

Epoxy resins have found various industrial applications in high-performance thermosetting resins, high-performance composites, electronic-packaging materials, adhesives, protective coatings, etc., due to their outstanding performance, including high toughness, high-temperature performance, chemical and environmental resistance, versatile processability and adhesive properties. However, cured epoxy resins are very brittle, which limits their applications. In this work, we attempted to enhance the toughness of cured epoxy resins by introducing benzene tetracarboxamide polyamine (BTCP), synthesized from pyromellitic dianhydride (PMDA) and diamines in N-methyl-2-pyrrolidone (NMP) solvent. During this reaction, increased viscosity and formation of amic acid could be confirmed. The chemical reactions were monitored and evidenced using ¹H-NMR spectroscopy, FT-IR spectroscopy, water gel-phase chromatography (GPC) analysis, amine value determination and acid value determination. We also studied the effect of additives on thermomechanical properties using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamical mechanical analysis (DMA), thermomechanical analysis (TMA) and by measuring mechanical properties. The BTCP-containing epoxy resin exhibited high mechanical strength and adhesion strength proportional to the amount of BTCP. Furthermore, field-emission scanning electron microscopy images were obtained for examining the cross-sectional morphology changes of the epoxy resin specimens with varying amounts of BTCP.

Surface treatment of halloysite nanotubes with sol–gel reaction for the preparation of epoxy composites

Halloysite nanotubes (HNTs) are naturally occurring aluminosilicates that have received attention for their high aspect ratio and low cost, which makes them suitable for commercial applications.

Control of silica-zirconia nanoparticles for uniform porous SiO2-ZrO2 membranes

Silica-zirconia composite sols were prepared by means of a sol-gel method, using tetraethylorthosilicate (TEOS) and zirconium tetra-n-butoxide (ZrTB) precursors. TEOS, ZrTB, HCl, H2O and EtOH were mixed at 70 degrees C for 24 hours to give molar ratios of 1:1:8-80:0.2-1.0:100-300. The mean particle size of the silica-zirconia sol was controlled by the concentration of the alkoxides and catalyst, as well as the water molar ratio in the starting solution. The particle size of the SiO2-ZrO2 sol, which was analyzed by dynamic light scattering (DLS) and field emission scanning electron microscopy (FE-SEM), was in the range of 20 to 350 nm. The SiO2-ZrO2 sol solutions of different sol sizes were coated onto porous stainless steel supports (O.D. 10 mm, length: 20 mm, 316L SUS, Mott corp. USA) by a dipping-rolling-freezing-fast drying (DRFF) and soaking-rolling-freezing-fast drying (SRFF) method. After coating with SiO2-ZrO2 sol, the single gas permeation characteristics (He, H2 and N2) of the resulting SiO2-ZrO2 membranes were evaluated at room temperature. This produced a decrease in the mean flow diameter and H2/N2 permselectivity in the range of 2.0-3.5. Finally, following the results of gas permeation testing, the pore size of the membranes was controlled by changing their particle size.

Comprehensive analysis of Excision repair complementation group 1, Glutathione S-transferase, Thymidylate synthase, and Uridine diphosphate glucuronosyltransferase 1A1 polymorphisms predictive for treatment outcome in patients with advanced gastric cancer treated with FOLFOX or FOLFIRI

e15580

Background: Pharmacogenetic advances in cancer chemotherapy have the potential to predict clinical benefit to particular regimens. Oxaliplatin and irinotecan have shown to be effective in the treatment of gastric cancer. We assessed whether single nucleotide polymorphisms (SNPs) in ERCC1, GST, TS, and UGT1A1predicted overall survival in gastric cancer patients receiving FOLFOX and/or FOLFIRI chemotherapy. Methods: Total genomic DNA was extracted from whole blood of patient. The PCR- restriction fragment length polymorphism (RFLP) method was applied to detect the known variant sites of ERCC1, GST, TS, and UGT1A1. Results: Response rate of FOLFOX (N=75) was 24%. Grade 3–4 neutropenia and neurotoxicity were observed 34.7% and 16%, respectively. TTP and OS of 1st line administration of FOLFOX (N=35) was 3.1 months (95% CI, 0.1–6.1 months) and 13.9 months (95% CI, 12.2–15.6 months). Only the GSTM1 positive genotype showed a significantly better time to progression (P=0.023). But significant genotype variation of TS, GST and ERCC1,which assumed to affect to activity of oxaliplatin was not observed to RR, toxicity, and overall survival. Response rate of FOLFIRI (N=74) was 23%. Grade 3–4 neutropenia and diarrhea were observed 55.4% and 9.5%, respectively. TTP and OS of 1st line administration of FOLFIRI (N=33) was 4.9 months (95% CI, 3.5–6.4 months) and 19.0 months (95% CI, 8.5–29.5months). Low expression type (2R/2R, 2R/3C, and 3C/3C) of TS was associated with high incidence of grade ≥3 neutropenia. But significant genotype variation of UGT1A1,which assumed to affect to toxicity of irinotecan was not observed to RR, toxicity, and survival. Conclusions: In this study, GSTM1 positive genotype showed a significantly better time to progression in the advanced gastric cancer treated with FOLFOX. Low expression type (2R/2R, 2R/3C, and 3C/3C) of TS was associated with high incidence of grade ≥3 neutropenia in the advanced gastric cancer treated with FOLFIRI. Well designed prospective trial will be clearly identifying relations between chemotherapy and genetic variations.

No significant financial relationships to disclose.

Apocrine carcinoma of the breast: clinical presentations, multimodality imaging findings and pathologic correlation

Abstract #4029

Background : 
 Apocrine carcinoma (AC) of the breast is a rare malignant tumor and is lack of standardized criteria for the diagnosis. Thus clinicopathological features and radiologic findings have not been determined. We retrospectively analyzed the clinical presentation and the multimodality imaging findings of mammography, ultrasography and MRI and correlated with pathologic results.
 Materials and Methods : 
 We retrospectively examined data on 850 patients who had been surgically treated for primary breast carcinoma between 2003 and 2008. Among them, there were 10 cases with the diagnosis of apocrine carcinoma.
 Ten patients underwent mammography and ultrasonography and six patients underwent MR imaging. Eight patients underwent pre-operative US-guided core needle biopsy. We analyzed the radiologic findings and pathologic results.
 Results : 
 The present study showed that the frequency of apocrine carcinoma was 1.2%. Almost all patients were symptomatic and painless lump was the most common complaint. Patient ranged in age from 38 to 62 year (mean, 50.5 years). The mean lesion size was 1.9cm (range, 1.1-3.5cm).
 Common imaging features were as follows: mass or focal asymmetry without microcalcifications (n=7), mass with microcalcifications (n=3) on mammography; a mass with an round to irregular shape (n=9), indistinct-margin(n=8) on ultrasonography. On six dynamic contrast-enhanced MRI, enhancing masses in 3, mass with spotty nodular enhancement adjacent to the tumor in 3, which showed rapid enhancement and delayed washout pattern in five cases and plateau enhancement pattern in one case. Specifically, 3 patients had unilateral multifocal cancer. Two patients showed ipsilateral axillary lymphadenopathy.
 Pathologic examination revealed AC (n=3), AC with apocrine carcinoma in situ (n=3), apocrine carcinoma in situ (n=1) and, AC with intraductal component and EIC positivity (n=3). Mass with spotty nodular enhancement on MRI was correlated with intraductal component and EIC positivity.
 Conclusion : 
 The radiologic findings of apocrine carcinoma of the breast are not specific. Occasionally, apocrine carcinoma shows mass with spotty nodular enhancement adjacent to the tumor on MRI and this finding is correlated with intraductal component and EIC positivity.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4029.

Estrogen affects vascular tone differently according to vasoactive substances in ovariectomized Sprague-Dawley rat

The favorable effects of estrogen on cardiovascular diseases can be explained by several mechanisms such as changes in serum lipid profiles and thrombogenecity. Estrogen also affects the vascular tone, but there has been no report in which the effect of estrogen was tested comprehensively for several vasoactive substances, especially after long-term administration. Two weeks after bilateral ovariectomy in 8-week old female Sprague-Dawley rats, placebo or 17 beta-estradiol (E2) pellets (0.5 mg; released over 3 weeks) were implanted subcutaneously. Two weeks after pellet implantation, organ chamber experiments were performed using aortae. Compared with control, E2-treated vessels showed impaired endothelium-dependent relaxation to acetylcholine. E2 enhanced the contraction to norepinephrine and U46619 and had no effect on endothelin-1-induced contraction. In contrast, the contraction to angiotensin (AT)-II was inhibited by E2. Northern blot analysis for AT1 receptor expression using cultured aortic smooth muscle cells showed no difference between control and E2-treated cells, suggesting that AT1 receptor downregulation is not the likely mechanism. These results suggest that E2 affects the vascular tone variably according to vasoactive substances.

Pasteurella multocida toxin stimulates mitogen-activated protein kinase via G(q/11)-dependent transactivation of the epidermal growth factor receptor

The dermatonecrotic toxin produced by Pasteurella multocida is one of the most potent mitogenic substances known for fibroblasts in vitro. Exposure to recombinant P. multocida toxin (rPMT) causes phospholipase C-mediated hydrolysis of inositol phospholipids, calcium mobilization, and activation of protein kinase C via a poorly characterized mechanism involving G(q/11) family heterotrimeric G proteins. To determine whether the regulation of G protein pathways contributes to the mitogenic effects of rPMT, we have examined the mechanism whereby rPMT stimulates the Erk mitogen-activated protein kinase cascade in cultured HEK-293 cells. Treatment with rPMT resulted in a dose and time-dependent increase in Erk 1/2 phosphorylation that paralleled its stimulation of inositol phospholipid hydrolysis. Both rPMT- and alpha-thrombin receptor- stimulated Erk phosphorylation were selectively blocked by cellular expression of two peptide inhibitors of G(q/11) signaling, the dominant negative mutant G protein-coupled receptor kinase, GRK2(K220R), and the Galpha(q) carboxyl-terminal peptide, Galpha(q)-(305-359). Like alpha-thrombin receptor-mediated Erk activation, the effect of rPMT was insensitive to the protein kinase C inhibitor GF109203X, but was blocked by the epidermal growth factor receptor-specific tyrphostin, AG1478 and by dominant negative mutants of mSos1 and Ha-Ras. These data indicate that rPMT employs G(q/11) family heterotrimeric G proteins to induce Ras-dependent Erk activation via protein kinase C-independent "transactivation" of the epidermal growth factor receptor.

Barbarin as a new tyrosinase inhibitor from Barbarea orthocerus

A tyrosinase inhibitor was isolated from the whole plant of Barbarea orthocerus Led. (Brassicaceae) by activity-guided fractionation, and identified as (R)-5-phenyl-2-oxazolidinethione (barbarin) by structural analysis followed by comparison with reported spectral data. The compound exhibited significant inhibitory effects on mushroom and murine tyrosinases at more than 1.6 x 10(-5) M. Barbarin exhibited IC50 values of 4.2 x 10(-5) M on mushroom tyrosinase and of 4.8 x 10(-5) M on murine tyrosinase. Kojic acid as a positive control exhibited IC50 values of 3.4 x 10(-5) M and 6.0 x 10(-5) M on mushroom and murine tyrosinases, respectively. Therefore, barbarin exhibited a similar level of inhibitory potency with kojic acid used as a positive control. In a kinetic study with various concentrations of L-dopa as the substrate, barbarin was identified as an uncompetitive inhibitor and kojic acid as a mixed inhibitor of both mushroom and murine tyrosinases. Barbarin exhibited KEIS values of 3.3 x 10(-5) M and 3.6 x 10(-5) M on mushroom and murine tyrosinases, respectively. Kojic acid exhibited KEIS and KEI values of 2.4 x 10(-5) M and 2.2 x 10(-5) M on mushroom tyrosinase and those of 8.9 x 10(-5) M and 7.2 x 10(-5) M on murine tyrosinase, respectively.

Toluene distribution of glue sniffers' biological fluid samples in Korea

We have studied the distribution of toluene in glue sniffers' biological fluid samples by gas chromatography or gas chromatography/mass spectrometry. The determined toluene concentrations ranged from 0.1 to 40.3 mg/L in urine samples and from 0.1 to 74.7 mg/L in blood samples, respectively. Among the 120 urine samples, 61% of all cases ranged between 0.1 and 1.0 mg/L and 27% was between 1.0 and 5.0 mg/L, respectively. On the other hand, 39% and 46% of all 99 blood samples ranged between 0.1 and 1.0 mg/L, or 1.0 and 5.0 mg/L, respectively. In the fatal cases (36 cases), the distribution of toluene ranged from 0.3 to 40.5 mg/L in the blood samples.

ETA and ETB receptors mediate contraction to endothelin-1 in renal artery of aging SHR. Effects of FR139317 and bosentan

We characterized vascular endothelin receptors of the renal artery from adult (12 to 16 weeks of age) and old (72 to 76 weeks) spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY). Vessels were suspended in organ chambers (37 degrees C, aerated with 95% O2/5% CO2), and isometric tension was recorded. The endothelin-A (ETA) receptor antagonist FR139317, the combined ETA/ETB receptor antagonist bosentan, and the ETB-selective agonist sarafotoxin S6c were used. In old (and less so in adult) SHR, cumulative concentration-contraction curves to endothelin-1 showed a small contraction resistant to FR139317 (10(-5) mol/L) at 3 x 10(-9) to 10(-8) mol/L endothelin-1, which was completely inhibited by bosentan (10(-5) mol/L). This FR139317-resistant contraction to endothelin-1 was not present in WKY. Furthermore, in the presence of FR139317 (10(-5) mol/L), sarafotoxin S6c induced a stronger contraction in old SHR than in WKY (P < .05). In rings contracted with norepinephrine, sarafotoxin S6c caused endothelium-dependent relaxations in both strains; these relaxations were blocked by N omega-nitro-L-arginine methyl ester, indicating that nitric oxide is the mediator. In WKY but not SHR, release of nitric oxide by sarafotoxin S6c increased with age (P < .05). Thus, both ETA and ETB receptors mediate contraction to endothelin-1 in the renal artery from SHR but not WKY. ETB receptors on vascular smooth muscle seem to be unmasked with age in SHR, whereas those on endothelium (mediating nitric oxide release) exhibit more efficient responses with age in WKY.

Both ETA and ETB receptors mediate contraction to endothelin-1 in human blood vessels

BACKGROUND

Endothelin (ET)-1 has potent vascular effects. Two endothelin receptors have been cloned, namely, the ETA receptor, which preferentially binds ET-1, and the ETB receptor, which equally binds ET-1 and ET-3 and preferentially sarafotoxin S6c. We characterized endothelin receptor subtypes on vascular smooth muscle and endothelium of isolated human internal mammary artery (IMA) and vein (IMV) and porcine coronary artery (PCA) using the ETA antagonists FR139317 and BQ-123, the ETB ligand sarafotoxin S6c, and the ETA/ETB antagonist Ro 47-0203 (bosentan).

METHODS AND RESULTS

In endothelium-denuded IMA and PCA and less so in IMV, FR139317 and BQ-123 (in PCA only) shifted the concentration-contraction curves to ET-1 parallel to the right. However, even at 10(-5) mol/L, FR139317 did not inhibit a high-sensitivity portion of the concentration-contraction curve. Moreover, the ETB receptor agonist sarafotoxin S6c induced contraction in vessels preincubated with FR139317. IMV was significantly more sensitive to the contractile effect of ET-1 and sarafotoxin S6c than was IMA (P < .05). Prolonged incubation with sarafotoxin S6c (to downregulate ETB receptors) and FR139317 eliminated the contraction resistant to FR139317. The ETA/ETB receptor antagonist bosentan caused a parallel shift of the concentration-contraction curve to the right at all concentrations of endothelin. ETB receptor mRNA was detected by Northern blot analysis in IMA and aortic smooth muscle cells. In precontracted IMA and PCA with endothelium, sarafotoxin S6c did not cause endothelium-dependent relaxations, whereas transient responses occurred in IMV.

CONCLUSIONS

Vascular smooth muscle cells of human IMA, IMV, and PCA contain both ETA and ETB receptors, whereas the endothelium of IMA and PCA does not express functional ETB receptors linked to nitric oxide and/or prostacyclin production. Hence, inhibition of endothelin-induced contraction in patients requires the use of combined ETA/ETB antagonists.