Active site engineering of Zn-doped mesoporous ceria toward highly efficient organophosphorus hydrolase-mimicking nanozyme

Hydrolase-mimicking nanozymes have received increasing attention in recent years, but the effective rational design and development of these materials has not been realized, as they are not at present considered a critical research target. Herein, we report that Zn-doped mesoporous ceria (Zn-m-ceria) engineered to have an abundance of two different active sites with different functions-one that allows both co-adsorption binding of organophosphate (OP) and water and another that serves as a general base-has significant organophosphorus hydrolase (OPH)-like catalytic activity. Specifically, Zn-m-ceria exhibits a catalytic efficiency over 75- and 25-fold higher than those of m-ceria and natural OPH, respectively. First-principles calculations reveal the importance of Zn for the OPH-mimicking activity of the material, promoting substrate adsorption and proton-binding. The OPH-like Zn-m-ceria catalyst is successfully applied to detect a model OP, methyl paraoxon, in spiked tap water samples with excellent sensitivity, stability, and detection precision. We expect that these findings will promote research based on the rational engineering of the active site of nanozymes and efficient strategies for obtaining a diverse range of catalysts that mimic natural enzymes, and hence the utilization in real-world applications of enzyme-mimicking catalysts with properties superior to their natural analogs should follow.

Updated assessment of occupational safety and health hazards of climate change

Workers, particularly outdoor workers, are among the populations most disproportionately affected by climate-related hazards. However, scientific research and control actions to comprehensively address these hazards are notably absent. To assess this absence, a seven-category framework was developed in 2009 to characterize the scientific literature published from 1988-2008. Using this framework, a second assessment examined the literature published through 2014, and the current one examines literature from 2014-2021. The objectives were to present literature that updates the framework and related topics and increases awareness of the role of climate change in occupational safety and health. In general, there is substantial literature on worker hazards related to ambient temperatures, biological hazards, and extreme weather but less on air pollution, ultraviolet radiation, industrial transitions, and the built environment. There is growing literature on mental health and health equity issues related to climate change, but much more research is needed. The socioeconomic impacts of climate change also require more research. This study illustrates that workers are experiencing increased morbidity and mortality related to climate change. In all areas of climate-related worker risk, including geoengineering, research is needed on the causality and prevalence of hazards, along with surveillance to identify, and interventions for hazard prevention and control.

Method for 3D atomic structure determination of multi-element nanoparticles with graphene liquid-cell TEM

Determining the 3D atomic structures of multi-element nanoparticles in their native liquid environment is crucial to understanding their physicochemical properties. Graphene liquid cell (GLC) TEM offers a platform to directly investigate nanoparticles in their solution phase. Moreover, exploiting high-resolution TEM images of single rotating nanoparticles in GLCs, 3D atomic structures of nanoparticles are reconstructed by a method called "Brownian one-particle reconstruction". We here introduce a 3D atomic structure determination method for multi-element nanoparticle systems. The method, which is based on low-pass filtration and initial 3D model generation customized for different types of multi-element systems, enables reconstruction of high-resolution 3D Coulomb density maps for ordered and disordered multi-element systems and classification of the heteroatom type. Using high-resolution image datasets obtained from TEM simulations of PbSe, CdSe, and FePt nanoparticles that are structurally relaxed with first-principles calculations in the graphene liquid cell, we show that the types and positions of the constituent atoms are precisely determined with root mean square displacement values less than 24 pm. Our study suggests that it is possible to investigate the 3D atomic structures of synthesized multi-element nanoparticles in liquid phase.

Tuning the Site-to-Site Interaction in Ru-M (M = Co, Fe, Ni) Diatomic Electrocatalysts to Climb up the Volcano Plot of Oxygen Electroreduction

The modulating of the geometric and electronic structures of metal-N-C atomic catalysts for improving their performance in catalyzing oxygen reduction reactions (ORRs) is highly desirable yet challenging. We herein report a delicate "encapsulation-substitution" strategy for the synthesis of paired metal sites in N-doped carbon. With the regulation of the d-orbital energy level, a significant increment in oxygen electroreduction activity was demonstrated in Ru-Co diatomic catalyst (DAC) compared with other diatomic (Ru-Fe and Ru-Ni) and single-atomic counterparts. The Ru-Co DAC efficiently reduces oxygen with a halfwave potential of 0.895 V vs RHE and a turnover frequency of 2.424 s^-1 at 0.7 V, establishing optimal thermodynamic and kinetic behaviors in the triple-phase reaction under practical conditions. Moreover, the Ru-Co DAC electrode displays bifunctional activity in a gas diffusion Zn-air battery with a small voltage gap of 0.603 V, outperforming the commercial Pt/C|RuO₂ catalyst. Our findings provide a clear understanding of site-to-site interaction on ORR and a benchmark evaluation of atomic catalysts with correlations of diatomic structure, energy level, and overall catalytic performance at the subnanometer level.

Two-Dimensional Palladium Phosphoronitride for Oxygen Reduction

Two-dimensional (2D) catalysts often show extraordinary activity at low mass loading since almost all their atoms are exposed to electrolyte. Palladium (Pd) holds great promise for catalyzing oxygen reduction reaction (ORR) but 2D Pd-based ORR catalyst has rarely been reported. Herein, 2D ternary palladium phosphoronitride (Pd₃P₂N_x) is synthesized, for the first time, for ORR catalysis. The synthesis is guided by a rational design using first-principles density functional theory calculations, and then realized via a postsynthesis substitutional doping of ternary palladium thiophosphate (Pd₃P₂S₈), which almost completely replaces sulfur atoms by nitrogen atoms without destroying the 2D morphology. The doping process exposes the interlocked Pd atoms of Pd₃P₂S₈ and introduces ligands that improve the affinity of oxygen intermediates, resulting in greater kinetics and lower activation energy for ORR. The mass activity of the pristine Pd₃P₂S₈ is dramatically increased as much as 5-fold (from 0.03 to 0.151 mA μg^-1 _Pd in Pd₃P₂N_x). The ORR diffusion-limited current density of Pd₃P₂N_x (6.2 mA cm^-2) exceeds that of commercial Pt/C, and it shows fast kinetics and robust long-term stability. Our theoretical calculations not only guide the experimental doping process, but also provides insights into the underlying mechanism of the outstanding ORR activity and stability.

Metastable hexagonal close-packed palladium hydride in liquid cell TEM

Metastable phases-kinetically favoured structures-are ubiquitous in nature^1,2. Rather than forming thermodynamically stable ground-state structures, crystals grown from high-energy precursors often initially adopt metastable structures depending on the initial conditions, such as temperature, pressure or crystal size^1,3,4. As the crystals grow further, they typically undergo a series of transformations from metastable phases to lower-energy and ultimately energetically stable phases^1,3,4. Metastable phases sometimes exhibit superior physicochemical properties and, hence, the discovery and synthesis of new metastable phases are promising avenues for innovations in materials science^1,5. However, the search for metastable materials has mainly been heuristic, performed on the basis of experiences, intuition or even speculative predictions, namely 'rules of thumb'. This limitation necessitates the advent of a new paradigm to discover new metastable phases based on rational design. Such a design rule is embodied in the discovery of a metastable hexagonal close-packed (hcp) palladium hydride (PdH_x) synthesized in a liquid cell transmission electron microscope. The metastable hcp structure is stabilized through a unique interplay between the precursor concentrations in the solution: a sufficient supply of hydrogen (H) favours the hcp structure on the subnanometre scale, and an insufficient supply of Pd inhibits further growth and subsequent transition towards the thermodynamically stable face-centred cubic structure. These findings provide thermodynamic insights into metastability engineering strategies that can be deployed to discover new metastable phases.

Species and characteristics of volatile organic compounds emitted from an auto-repair painting workshop

Volatile organic compounds (VOCs) are secondary pollutant precursors having adverse impacts on the environment and human health. Although VOC emissions, their sources, and impacts have been investigated, the focus has been on large-scale industrial sources or indoor environments; studies on relatively small-scale enterprises (e.g., auto-repair workshops) are lacking. Here, we performed field VOC measurements for an auto-repair painting facility in Korea and analyzed the characteristics of VOCs emitted from the main painting workshop (top coat). The total VOC concentration was 5069-8058 ppb, and 24-35 species were detected. The VOCs were mainly identified as butyl acetate, toluene, ethylbenzene, and xylene compounds. VOC characteristics differed depending on the paint type. Butyl acetate had the highest concentration in both water- and oil-based paints; however, its concentration and proportion were higher in the former (3256 ppb, 65.5%) than in the latter (2449 ppb, 31.1%). Comparing VOC concentration before and after passing through adsorption systems, concentrations of most VOCs were lower at the outlets than the inlets of the adsorption systems, but were found to be high at the outlets in some workshops. These results provide a theoretical basis for developing effective VOC control systems and managing VOC emissions from auto-repair painting workshops.

First-Principles-Based Machine-Learning Molecular Dynamics for Crystalline Polymers with van der Waals Interactions

Machine-learning (ML) techniques have drawn an ever-increasing focus as they enable high-throughput screening and multiscale prediction of material properties. Especially, ML force fields (FFs) of quantum mechanical accuracy are expected to play a central role for the purpose. The construction of ML-FFs for polymers is, however, still in its infancy due to the formidable configurational space of its composing atoms. Here, we demonstrate the effective development of ML-FFs using kernel functions and a Gaussian process for an organic polymer, polytetrafluoroethylene (PTFE), with a data set acquired by first-principles calculations and ab initio molecular dynamics (AIMD) simulations. Even though the training data set is sampled only with short PTFE chains, structures of longer chains optimized by our ML-FF show an excellent consistency with density functional theory calculations. Furthermore, when integrated with molecular dynamics simulations, the ML-FF successfully describes various physical properties of a PTFE bundle, such as a density, melting temperature, coefficient of thermal expansion, and Young's modulus.

Unique design of superior metal-organic framework for removal of toxic chemicals in humid environment via direct functionalization of the metal nodes

Unique chemical and thermal stabilities of a zirconium-based metal-organic framework (MOF) and its functionalized analogues play a key role to efficiently remove chemical warfare agents (ex., cyanogen chloride, CNCl) and simulant (dimethyl methylphosphonate, DMMP) as well as industrial toxic gas, ammonia (NH₃). Herein, we for the first time demonstrate outstanding performance of MOF-808 for removal of toxic chemicals in humid environment via special design of functionalization of hydroxo species bridging Zr-nodes using a triethylenediamine (TEDA) to form ionic frameworks by gas phase acid-base reactions. In situ experimental analyses and first-principles density functional theory calculations unveil underlying mechanism on the selective deposition of TEDA on the Zr-bridging hydroxo sites (μ₃-OH) in Zr-MOFs. The crystal structure of TEDA-grafted MOF-808 was confirmed using synchrotron X-ray powder diffraction (SXRPD). Furthermore, operando FT-IR spectra elucidate why the TEDA-grafted MOF-808 shows by far superior sorption efficiency to other MOF varieties. This work provides design principles and applications how to optimize MOFs for the preparation for versatile adsorbents using diamine grafting chemistry, which is also potentially applicable to various catalysis.

Critical differences in 3D atomic structure of individual ligand-protected nanocrystals in solution

Precise three-dimensional (3D) atomic structure determination of individual nanocrystals is a prerequisite for understanding and predicting their physical properties. Nanocrystals from the same synthesis batch display what are often presumed to be small but possibly important differences in size, lattice distortions, and defects, which can only be understood by structural characterization with high spatial 3D resolution. We solved the structures of individual colloidal platinum nanocrystals by developing atomic-resolution 3D liquid-cell electron microscopy to reveal critical intrinsic heterogeneity of ligand-protected platinum nanocrystals in solution, including structural degeneracies, lattice parameter deviations, internal defects, and strain. These differences in structure lead to substantial contributions to free energies, consequential enough that they must be considered in any discussion of fundamental nanocrystal properties or applications.

[Interpretation for diagnosis of Yersiniosis]

Yersiniosis is one of the "other infectious diarrhea" of the notifiable infectious diseases and also an important food-borne disease. However, it lacked the basis or standard for diagnosis. The Chinese Preventive Medicine Association coordinated experienced researchers from National Institute for Communicable Disease Control and Prevention, China CDC and other institutes to produce the group standard entitled "Diagnosis of Yersiniosis" (T/CPMA 005-2019). Based on the principle of "legality, scientificity, advancement, and feasibility" , the standard gives a clear definition for Yerisiniosis, stipulates diagnosis basis, principles and main differential diagnosis and provides two informative appendixes for epidemiological and clinical characteristics and a normative appendix for laboratory detection. The standard provides accurate basis and methods of Yersiniosis diagnosis for hospitals and CDCs at all levels in China. It will solve the problems that Yersiniosis cannot be clearly diagnosed for clinical cases and in the outbreaks.

Astrocytic water channel aquaporin-4 modulates brain plasticity in both mice and humans: a potential gliogenetic mechanism underlying language-associated learning

The role of astrocytes in brain plasticity has not been extensively studied compared with that of neurons. Here we adopted integrative translational and reverse-translational approaches to explore the role of an astrocyte-specific major water channel in the brain, aquaporin-4 (AQP4), in brain plasticity and learning. We initially identified the most prevalent genetic variant of AQP4 (single nucleotide polymorphism of rs162008 with C or T variation, which has a minor allele frequency of 0.21) from a human database (n=60 706) and examined its functionality in modulating the expression level of AQP4 in an in vitro luciferase reporter assay. In the following experiments, AQP4 knock-down in mice not only impaired hippocampal volumetric plasticity after exposure to enriched environment but also caused loss of long-term potentiation after theta-burst stimulation. In humans, there was a cross-sectional association of rs162008 with gray matter (GM) volume variation in cortices, including the vicinity of the Perisylvian heteromodal language area (Sample 1, n=650). GM volume variation in these brain regions was positively associated with the semantic verbal fluency. In a prospective follow-up study (Sample 2, n=45), the effects of an intensive 5-week foreign language (English) learning experience on regional GM volume increase were modulated by this AQP4 variant, which was also associated with verbal learning capacity change. We then delineated in mice mechanisms that included AQP4-dependent transient astrocytic volume changes and astrocytic structural elaboration. We believe our study provides the first integrative evidence for a gliogenetic basis that involves AQP4, underlying language-associated brain plasticity.

First principles computational study on hydrolysis of hazardous chemicals phosphorus trichloride and oxychloride (PCl3 and POCl3) catalyzed by molecular water clusters

Using first principles calculations we unveil fundamental mechanism of hydrolysis reactions of two hazardous chemicals PCl₃ and POCl₃ with explicit molecular water clusters nearby. It is found that the water molecules play a key role as a catalyst significantly lowing activation barrier of the hydrolysis via transferring its protons to reaction intermediates. Interestingly, torsional angle of the molecular complex at transition state is identified as a vital descriptor on the reaction rate. Analysis of charge distribution over the complex further reinforces the finding with atomic level correlation between the torsional angle and variation of the orbital hybridization state of phosphorus (P) in the complex. Electronic charge separation (or polarization) enhances thermodynamic stability of the activated complex and reduces the activation energy through hydrogen bonding network with water molecules nearby. Calculated potential energy surfaces (PES) for the hydrolysis of PCl₃ and POCl₃ depict their two contrastingly different profiles of double- and triple-depth wells, respectively. It is ascribed to the unique double-bonding O=P in the POCl₃. Our results on the activation free energy show well agreements with previous experimental data within 7kcalmol^-1 deviation.

First-principles database driven computational neural network approach to the discovery of active ternary nanocatalysts for oxygen reduction reaction

An elegant machine-learning-based algorithm was applied to study the thermo-electrochemical properties of ternary nanocatalysts for oxygen reduction reaction (ORR).

Visible light communication using InGaN optical sources with AlInGaP nanomembrane down-converters

We report free space visible light communication using InGaN sources, namely micro-LEDs and a laser diode, down-converted by a red-emitting AlInGaP multi-quantum-well nanomembrane. In the case of micro-LEDs, the AlInGaP nanomembrane is capillary-bonded between the sapphire window of a micro-LED array and a hemispherical sapphire lens to provide an integrated optical source. The sapphire lens improves the extraction efficiency of the color-converted light. For the case of the down-converted laser diode, one side of the nanomembrane is bonded to a sapphire lens and the other side optionally onto a dielectric mirror; this nanomembrane-lens structure is remotely excited by the laser diode. Data transmission up to 870 Mb/s using pulse amplitude modulation (PAM) with fractionally spaced decision feedback equalizer is demonstrated for the micro-LED-integrated nanomembrane. A data rate of 1.2 Gb/s is achieved using orthogonal frequency division multiplexing (ODFM) with the laser diode pumped sample.

First principles computational study on the adsorption mechanism of organic methyl iodide gas on triethylenediamine impregnated activated carbon

We study the removal of gas-phase organic methyl iodide (CH₃I) from an ambient environment via adsorption onto triethylenediamine (TEDA) impregnated activated carbon (AC).

A trial of questionnaire administration modalities for measures of sexual risk behaviour in the uniformed services of Peru

Summary

Modalities of questionnaire administration may affect data quality, particularly when conducting Biological and Behavioral Surveillance Surveys (BBSS) of uniformed personnel. We aimed to examine differences in administration, reporting and data quality across several common modalities of administration for BBSS endeavors. Prior to a large-scale BBSS endeavor with the uniformed services of Peru, we pilot tested three modes of questionnaire administration among personnel engaged in internal combat: face-to-face interview (FFI), self-administered paper-based interview (SAPI), and audio computer-assisted self-interview (ACASI). Individuals who took the survey using ACASI were less likely to have missing data on measures of sexual risk and alcohol abuse and were more likely to report sexual risk behaviours and symptoms of alcohol abuse; however, more individuals took the survey using SAPI given inadequate time to devote to sitting through an entire FFI or ACASI. Sexually transmitted infections did not vary significantly across modes of questionnaire administration. While more logistically complicated for BBSS efforts in resource-constrained settings, we recommend the use of ACASI in collecting BBSS data from uniformed personnel if conditions are permissible.

High-throughput on-chip leukemia diagnosis

Advances in lab-on-a-chip technologies enabled programmable, reconfigurable, and scalable manipulation of a variety of laboratory procedures. Samples, reagents, and fluids can be precisely controlled; buffer temperature, pH, and concentration control systems as well as a variety of detection systems can be integrated on a small chip. These advantages have attracted attention in various fields of clinical application including leukemia diagnosis and research. A lot of research on lab-on-a-chip based diagnosis has been reported and the field is rapidly expanding. This review describes recent developments of lab-on-a-chip technologies as solutions to challenges for high-throughput leukemia diagnosis.

Relationship between response rate and median survival in patients with advanced nonsmall cell lung-cancer - comparison of onconase(r) with other anticancer agents

The role of systemic cytotoxic therapy for the treatment of advanced non-small cell lung cancer (NSCLC) remains controversial. The response rate (RR) and the median survival time (MST) are the two most frequently used parameters for the assessment of efficacy of the anti-cancer therapies. The relationship between the previously reported RRs and MSTs from published chemotherapy trials in patients with advanced NSCLC was examined using linear regression analysis. The MST of the thirty patients with advanced NSCLC treated with ONCONASE (ONC) as a single agent was 7.7 months which compared favorably with the MSTs of patients treated with a variety of chemotherapeutic regimens either as single agents or combinations, as well as placebo and supportive care only. Moreover, the toxicity profile of ONC compared favorably to the profiles of other chemotherapy regimens. ONC had a favorable impact on the overall MST, including patients with stage IV disease, patients with poor performance status, and patients previously treated with radiotherapy and chemotherapy. The MST of 5 patients who had a stabilization of previously progressive disease was 9.3 months. Based on its positive impact on the MST, ONC appears to have a single agent activity in patients with advanced NSCLC, and it should be further investigated, particularly in combination with synergistic drugs, in concurrently controlled and prospectively randomized clinical trials. The duration and the quality of survival should be considered as the most meaningful parameters in assessing clinical efficacy of anti-cancer agents.

Bilayer graphene grown on 4H-SiC (0001) step-free mesas

We demonstrate the first successful growth of large-area (200 × 200 μm(2)) bilayer, Bernal stacked, epitaxial graphene (EG) on atomically flat, 4H-SiC (0001) step-free mesas (SFMs) . The use of SFMs for the growth of graphene resulted in the complete elimination of surface step-bunching typically found after EG growth on conventional nominally on-axis SiC (0001) substrates. As a result heights of EG surface features are reduced by at least a factor of 50 from the heights found on conventional substrates. Evaluation of the EG across the SFM using the Raman 2D mode indicates Bernal stacking with low and uniform compressive lattice strain of only 0.05%. The uniformity of this strain is significantly improved, which is about 13-fold decrease of strain found for EG grown on conventional nominally on-axis substrates. The magnitude of the strain approaches values for stress-free exfoliated graphene flakes. Hall transport measurements on large area bilayer samples taken as a function of temperature from 4.3 to 300 K revealed an n-type carrier mobility that increased from 1170 to 1730 cm(2) V(-1) s(-1), and a corresponding sheet carrier density that decreased from 5.0 × 10(12) cm(-2) to 3.26 × 10(12) cm(-2). The transport is believed to occur predominantly through the top EG layer with the bottom layer screening the top layer from the substrate. These results demonstrate that EG synthesized on large area, perfectly flat on-axis mesa surfaces can be used to produce Bernal-stacked bilayer EG having excellent uniformity and reduced strain and provides the perfect opportunity for significant advancement of epitaxial graphene electronics technology.

HIV infection, sexual risk behaviour and condom use in the Belize defense force

This study is the first Biological and Behavioral Surveillance Survey to be conducted among personnel in the Belize Defense Force. The purpose of the study was to understand the prevalence of HIV infection and risk behaviours, and to identify key correlates of sexual risk behaviours. A representative sample of personnel underwent serological testing and an Audio Computer-Assisted Self Interview. Of those sampled, 351 completed a blood test and 334 completed a behavioural interview. The prevalence of HIV was 1.14%. Twelve percent had ever reported being diagnosed with a sexually transmitted infection (STI) or screened positive for HIV infection. The odds of ever having an STI/HIV were higher among those who had less education, those who had sex with a commercial sex worker (CSW), those who ever engaged in receptive anal sex and those with post-traumatic stress disorder (PTSD). Alcohol abuse and PTSD were prevalent and associated with HIV risk behaviours. These results are being used to inform current prevention efforts.

Ethanol-induced DNA damage and the expression of repair-related molecules in human gastric carcinoma AGS cells with use of an acid pump antagonist and proton pump inhibitor

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Background: Proton pump inhibitor (PPI) inhibits gastric acid secretion by strongly suppressing H + / K +- ATPase of parietal cells and is a major drug for peptic ulcers and gastroesophageal reflux. Recently it was reported that PPI has antioxidant and anti- inflammatory effects as well as a powerful acid inhibitory effect. To analyze the DNA repair capacity from the antioxidant effect of acid pump antagonist (Revanex-RN) and proton pump inhibitor (Omeprazole-OP), this study examined ethanol-induced DNA damage and the expression of repair related molecules in human gastric cancer AGS cells pretreated with an acid pump antagonist and a proton pump inhibitor.

Methods: AGS, a human gastric cancer cell line was obtained from ATCC, was treated with ethanol (0, 2, 4, 6, 8, 10%) during 1hr. MTT and Comet assay were performed to evaluate ethanol-induced DNA damage. The optimum concentration of ethanol which caused DNA damage was established. And AGS cells were cultured in proper concentration of RN or OP overnight. Then, these cells were treated with 5% ethanol during 1hr. DNA damage and recovery were represented the value of Olive tail moment in comet assay. Western blot was also performed to detect expression of DNA polymerase beta, APE/ref-1, PCNA, and GADD45.

Results: The DNA damage of AGS cell depended upon ethanol concentration distinctly. Damaged cells showed up recovered tendency in the group treated with low dose RN or OP. In addition, DNA repair enzymes including DNA polymerase beta and APE/ref-1 which were associated with mechanism of base excision repair (BER) were increased. A relevant protein such as GADD45 was also increased significantly.

Conclusions: PPI has capacity to recover damaged DNA, which is associated with increased expression of GADD45 directly. Therefore, PPI offers cancer prevention by reducing the level of DNA damage in the gastric mucosa. GADD45 is also likely to suggest that it could be used a major factor on the injury mechanism and an indicator of mucosal damage in stomach. Moreover, RN, an acid pump antagonist is expected to have the higher safety compared to the existing PPIs and considered to be equal to PPIs in terms of anti-cancer effect.

No significant financial relationships to disclose.

Novel multiphoton microscopy probe and feasibility study for colon cancer: Probe on trace elements–related antioxidant

463

Background: Multiphoton microscopy (MPM) has gained increasing popularity during the past few years because of the distinct advantages over single-photon microscopy, which includes increased penetration depth and low out-of-focus photodamage. However, there had been no report on multiphoton probes for malignancy. Previous studies reported that Zn and Cu ions which are co-factor of antioxidants such as superoxide dismutase (SOD), altered in malignancy tissue. The aim of this study was to evaluate application of the multiphoton (MP) probe of Zn and Cu for colon cancer tissues.

Methods: We monitored the Zn/Cu ions in the colon cancer cell lines with multiphoton probe Microscopy. The multiphoton probe AZn2+ (C38H38N6O3) and ACu+ (C34H47N3O3S4), we developed and obtained the patent on it, were stained in live cancer cell lines. The tissues of colon cancer, adenoma and normal mucosa were obtained by biopsy during colonoscopy. Then the tissues were stained with 20μM of the MP probes for Zn/Cu ions. The distribution and concentration of zinc and copper ions were monitored by MPM by following the change in MPEF along the depth of tissue.

Results: The majority of Zn2+ and Cu+ ions distributed in cytosole. The average multi-photon excited fluorescence (MPEF) intensities due to Cu, Zn, and Cu/Zn ratio were remarkably different between the normal mucosa and adenoma/adenocarcinoma tissues. The Zn2+ content was significantly lower and the Cu2+ content was significantly higher to result in a much lower the Zn/Cu ratio in adenoma/adenocarcinoma than in normal mucosa tissues.

Conclusions: We have obtained multiphoton microscopy images of normal and cancer cell lines as well as mucosa and adenoma/adenocarcinoma tissues labeled with newly developed MP probes AZn1 and ACu1.

No significant financial relationships to disclose.

Polymorphism of nucleotide excision repair genes as predictors for clinical outcome in advanced gastric cancer patients treated with oxaliplatin-based chemotherapy

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Background: The individual variations in treatment response and the toxicity of combination regimen of oxaliplatin and 5-fluorouracil with leucovorin (FOLFOX) for advanced gastric cancer patients have been reported. The aim of this study is to evaluate the influence of polymorphism of nucleotide excision repair genes that are involved in the metabolism of cisplatin on the clinical outcomes of gastric cancer patients treated with modified FOLFOX-6 chemotherapy. Methods: From March 2006 to December 2007, eighty-two patients with advanced gastric cancer were treated with modified FOLFOX-6 as the primary chemotherapy in our institution. Of these patients, 55 patients who were available for peripheral blood sampling before starting chemotherapy were enrolled in this study. Genomic DNA was extracted from mononuclear cells of patients’ blood. Four polymorphisms were investigated in three genes, ERCC, GSTP and XRCC. Results: The overall response rate (RR) was 40.0%. Median time to progression (TTP) and overall survival (OS) was 6 months (C.I.: 5.0 - 7.0 months) and 15.0 months (C.I.: 9.7 - 20.3 months). Grade 3 or 4 hematologic toxicities were presented in 17 patients (30.9%), gastrointestinal toxicities in 5 patients (9.1%), peripheral neuropathy in 5 patients (9.1%) and hepato-toxicity in 4 patients (7.3%). Most common types of polymorphism were G/G (67.3%) in XRCC1 Arg399Gln, A/A (74.5%) in GSTP1 Ile105Val, C/C (60.0%) in ERCC1 Asn118Asn and C/A (49.1%) in ERCC1 C8092A. The RR was significantly lower in patients with C/C type in ERCC1 C8092A gene than those with other type (25.0% vs 51.6%, p=0.046). However, there were no differences of TTP and OS among the polymorphisms in three genes. The rate of grade 3 or 4 hematologic toxicity was higher in patients with C/T or T/T in ERCC1 codon 118 gene than those with C/C type (45.5% vs 21.2%, p=0.057). Conclusions: We demonstrated that modified FOLFOX-6 chemotherapy was effective and tolerable. The polymorphism of C/C type in ERCC1 C8092A gene was found to be a predictive marker of the poor response and C/C type in ERCC1 Asn118Asn gene was to be a predictive marker of the hematologic toxicity.

No significant financial relationships to disclose.

A phase I study of TPI287: A third generation taxane administered weekly in patients with advanced cancer

2575

Background: TPI 287 is an investigational taxane designed to not be a substrate for mdr-1 and to bind to mutant tubulin. In preclinical studies, TPI 287 demonstrated activity against multiple human tumor xenografts in nude mice, including xenografts that expressed mdr-1 and that were resistant to other taxanes. The safety and tolerability of TPI 287 when administered weekly for 3 weeks followed by a 1 week rest (4 week cycle) was examined in this Phase 1 dose escalation study in patients (pts) with advanced neoplasms. Materials and Methods: TPI 287 was administered over 1 hour weekly for 3 weeks followed by 1 week of no treatment. Treatment cohorts consisted of 3 pts and were expanded to 6 pts in the face of dose-limiting toxicity (DLT); pts could remain on study until the development of progressive disease or an intolerable adverse event. DLT was defined as Gr 4 heme toxicity lasting 7 days; febrile neutropenia, Gr 3 thrombocytopenia with bleeding, Gr 3 elevation of transaminases lasting 7 days or any other Gr 3/4 toxicity other than nausea or vomiting. Results: 25 pts (M:F 16:9, median age 60, range 24 - 86) were enrolled in 7 dose levels ranging from 7–185 mg/m2. Pts’ cancers included colorectal (6 pts); NSCLC (2); prostate (2); squamous cell carcinoma (2) and 1 pt each with cervical, breast, ovarian, gastric, pancreatic, bladder endometrial, NSCLC, SCLC, glioblastoma, melanoma, renal cell and hepatocellular carcinoma. All pts but 1 had received prior chemotherapy (median no. prior treatments: 3 (range, 1–7). Drug related adverse events included nausea, vomiting, diarrhea, fatigue, anorexia, rash, anemia and peripheral neuropathy. 1 pt., who was inadvertently treated with inadequate marrow reserve, experienced Gr 4 neutropenia and died of sepsis. DLT of Grade 3 peripheral neuropathy has been observed. PK data to date reveal that AUC is generally dose linear. At a dose of 127.5 mg/m2, clearance was 30.2 + 11.9 L/hr/m2 and t1/2 8.6 + 1.3 hrs. Results are similar with non-compartmental methods and 2-compartment modeling. Conclusions: TPI 287 can be safely administered in doses of up to 127.5 mg/m2 weekly x 3.

No significant financial relationships to disclose.

Prognostic Significance of β-catenin in Colorectal Cancer with Liver Metastasis

AIMS

A decreased expression of beta-catenin has been known to be associated with tumour metastasis. The prognostic value of beta-catenin expression in colorectal cancer (CRC) patients with liver metastasis was evaluated.

MATERIALS AND METHODS

Seventy patients who underwent curative resection for CRC with liver metastasis were included. Tissue samples from normal colon mucosa, primary CRC and metastatic liver lesions were prepared in tissue microarrays, and were stained by immunohistochemistry with beta-catenin antibody. The beta-catenin expression of primary CRC tissues and metastatic liver tissues was analysed.

RESULTS

A high expression of beta-catenin (score > 6) was observed in 42.0% and 21.9% of primary colorectal tissues and metastatic liver tissues, respectively. The beta-catenin expression in metastatic liver tissues was significantly lower than in primary CRC tissues (P = 0.022). The patients were classified into two groups according to the difference in the beta-catenin expression score between the primary CRC and the liver metastasis. Group A was defined as patients showing a remarkably decreased expression of beta-catenin in their metastatic liver tissue and group B was defined as patients showing a maintained or increased beta-catenin expression in their metastatic liver tissue in comparison with their primary CRC. The overall survival and disease-free survival rates were better in group B than in group A, and this was statistically significant (P = 0.02, P = 0.002).

CONCLUSION

The decreased expression of beta-catenin in a metastatic liver lesion may be a poor prognostic marker in CRC with liver metastasis and further investigation is necessary.

Therapeutic use of granulocyte-colony stimulating factor could conceal residual malignant cells in patients with AML1/ETO+ acute myelogenous leukemia

We have experienced a number of cases of AML1/ETO+ acute myelogenous leukemia that showed remission based on bone marrow (BM) morphological criteria, but that revealed clonal abnormalities in most cells by fluorescence in situ hybridization (FISH). Interestingly, most of these cases had AML with AML1/ETO rearrangement. The malignant cells were differentiated and considered mature cells after granulocyte-colony stimulating factor (G-CSF) treatment. To clarify the possible mechanisms underlying this phenomenon, we investigated the expression levels of G-CSFR in AML cells with AML1/ETO rearrangement by flow cytometry and real-time polymerase chain reaction (PCR). The number of AML1/ETO+ cells expressing G-CSFR at baseline was significantly higher than that of AML1/ETO- AML cells (2673 vs 522). In addition, the G-CSFR gene was more highly expressed in AML1/ETO+ cells than in AML1/ETO- cells by real-time PCR. This study reveals that cases showing remission after treatment with G-CSF mostly had leukemia with AML1/ETO rearrangement. This finding might be explained by the higher expression of G-CSF receptor in AML1/ETO+ cells than in AML1/ETO- cells. We recommend that remission should be confirmed by FISH, because malignant clones can be differentiated and masked in morphological examination or chromosome test, especially for AML with AML1/ETO rearrangement.

A Q7D phase I study of TPI 287, a novel taxane, in advanced malignancies: Imaging studies, pharmacokinetics (PK) and circulating tumor cell (CTC) quantitation

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Background: Taxanes have demonstrated activity across a broad range of cancers, but resistance remains an issue. TPI 287 is a third generation taxane designed to overcome issues of resistance secondary to mdr and mutant tubulin. The purpose of this Phase I study was to determine the maximum tolerated dose and pharmacokinetics of IV TPI 287. Methods: Phase I study: TPI 287 is administered IV on days 1, 8, 15 of a 28 day cycle (Q7D) with at least 3 patients treated per dose escalation, in a typical phase I design. Dosing began at 7 mg/m2 and has advanced to the fifth cohort of patients, who are being treated at a dose of 85 mg/m2. Tumor response is assessed after every second cycle via imaging and tumor measurements. Samples are collected for PK analysis and circulating tumor cell (CTC) quantitation. Results: Sixteen pts have been enrolled (9 males, median years = 60.11; 7 females, median years = 50.71: median number of previous chemotherapies = 4). Diagnoses included colorectal (4), prostate (3), breast, kidney, cervical, brain, lung, osteosarcoma, basal cell, endometrial, ovarian cancers. Of 16 pts, 8 and 5 have completed 1, 2 cycles, respectively. Only one drug related grade 3 adverse event (hypersensitivity reaction) occurred, at 14 mg/m2. No other reported toxicities are related to TPI 287. PK and CTC studies are ongoing. Conclusions: These initial results show that TPI 287 is well tolerated at a dose up to 56 mg/m2 administered Q7D, and dose escalation continues.

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Transanal endoscopic microsurgery and radical surgery for T1 and T2 rectal cancer

BACKGROUND

Transanal endoscopic microsurgery (TEM) has gained increasing acceptance as a local treatment of early rectal cancer. The purpose of this study was to compare the results of TEM and radical surgery in patients with T1 and T2 rectal cancer.

METHODS

From October 1994 to December 2000, 74 patients with T1 and T2 rectal adenocarcinoma treated with TEM were compared with 100 patients with T1N0M0 and T2N0M0 rectal adenocarcinoma treated with radical surgery. Retrospective analysis was performed regarding to recurrence and survival rate. Neither group received adjuvant chemoradiation. There was no significant difference in age, gender, tumor location, or follow-up period between the two groups. The only difference was in tumor size.

RESULTS

Of the 74 patients in TEM group, 52 were T1 (70.3%) and 22 were T2 (29.7%). Of the 100 patients in radical surgery group, 17 were T1 (17%) and 83 patients were T2 (83%). The 5-year local recurrence rates were 4.1% for T1, 19.5% for T2 after TEM, 0% for T1, and 9.4% for T2 after radical surgery. There was no statistical difference between the TEM and radical surgery groups for T1 rectal cancer ( p = 0.95), but for T2 rectal cancer, the 5-year local recurrence rate was higher after TEM than after radical surgery ( p = 0.04). There were no significant statistical difference between the two groups in terms of the 5-year disease-free survival rate and the survival rate.

CONCLUSIONS

For T1 rectal cancer, there was no difference in recurrence or 5-year survival rate between the TEM and the radical surgery groups. For T2 rectal cancer, there was no statistical difference in the 5-year survival rate between the two groups, but TEM carried higher risk of local recurrence. Therefore, careful selection of the patients is required for TEM, and when proper muscle invasion is proven, the TEM procedure should be supplemented by further treatment, or radical surgery should be performed.

Molecular and electronic structure of octahedral o-aminophenolato and o-iminobenzosemiquinonato complexes of V(V), Cr(III), Fe(III), and Co(III). Experimental determination of oxidation levels of ligands and metal ions

The coordination chemistry of the ligands 2-anilino-4,6-di-tert-butylphenol, H[L(AP)], and N,N"'-bis[2-(4,6-di-tert-butylphenol]diethylenetriamine, H(2)[(L(AP))N(L(AP))], has been studied with the first-row transition metal ions V, Cr, Fe, and Co. The ligands are noninnocent in the sense that the aminophenolato parts, [L(AP)](-) and [L(AP)-H](2)(-), can be readily oxidized to their o-iminobenzosemiquinonato, [L(ISQ)](-), and o-iminobenzoquinone, [L(ISB)], forms. The following neutral octahedral complexes have been isolated as crystalline materials, and their crystal structures have been determined by X-ray crystallography at 100 K: [Cr(III)(L(ISQ))(3)] (1), [Fe(III)(L(ISQ))(3)] (2), [Co(III)(L(ISQ))(3)] (3), [V(V)(L(ISQ))(L(AP)-H)(2)] (4), [V(V)(L(AP)-H)(2)(L(AP))] (5), and [V(V)O[(L(AP))N(L(AP)-H)]] (6). From variable-temperature magnetic susceptibility measurements and X-band EPR spectroscopy it has been established that they possess the ground states: 1, S = 0; 2, S = 1; 3, S = (3)/(2); 4, S = (1)/(2); 5, S = 0; 6, S = 0. The o-iminobenzosemiquinonato radicals (S(rad) = (1)/(2)) couple strongly intramolecularly antiferromagnetically to singly occupied orbitals of the t(2g) subshell at the respective metal ion but ferromagnetically to each other in 3 containing a Co(III) ion with a filled t(2g)(6) subshell. It is demonstrated that the oxidation level of the ligands and metal ions can be unequivocally determined by high-quality X-ray crystallography in conjunction with EPR, UV-vis, and Mössbauer spectroscopies. The spectro- and electrochemistry of these complexes have also been studied in detail. Metal- and ligand-based redox chemistry has been observed. The molecular and electronic structures are compared with those of their o-semiquinonato analogues.