Identification of the Optimal Framework for Nitroxyl Radical/Hydroxylamine in Copper-Cocatalyzed Aerobic Alcohol Oxidation.

8-Azabicyclo[3.2.1]octan-8-ol (ABOOL) and 7-azabicyclo[2.2.1]heptan-7-ol (ABHOL) are the main homologues of hydroxylamine 2-azaadamantan-2-ol (AZADOL) and 9-azabicyclo[3.3.1]nonan-9-ol. Both homologues feature a small bicyclic backbone and are known to be stable; however, to date, they have not been used as catalysts for alcohol oxidation. Herein, we report that these hydroxylamines can efficiently catalyze the oxidation of various secondary alcohols to their corresponding ketones using molecular oxygen in ambient air as the terminal oxidant and copper cocatalysts at room temperature. Furthermore, we show that ABOOL and ABHOL can be easily synthesized from commercially available materials.

Nitroxyl Radical/Copper-Catalyzed Electrooxidation of Alcohols and Amines at Low Potentials.

Nitroxyl radicals, such as 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO), can catalyze the electrochemical oxidation of alcohols and amines. Because the oxidation current obtained in this process depends on the concentration of alcohols and amines, this process can be applied to their sensing. However, the relatively high oxidation potentials required by nitroxyl radicals can induce interfering oxidation currents from various reductive substances in biological samples, which affects the accuracy of analyte measurements. In this study, we examined the electrooxidation of alcohols and amines at a low potential by applying cooperative oxidation catalysis using a nitroxyl radical and a copper salt. Nortropine N-oxyl (NNO), which showed higher catalytic activity than TEMPO was used as the nitroxyl radical. An increase in the oxidation current was observed at the low potential, and this increase depended on the alcohol concentration. In the case of the electrooxidation of amines, a positive correlation between oxidation current and amine concentration was observed at low amine concentrations. Therefore, low-potential cooperative catalysis can be applied to alcohol and amine electrooxidation for the development of accurate sensors suitable for clinical settings.

Thymine DNA glycosylase modulates DNA damage response and gene expression by base excision repair-dependent and independent mechanisms.

Thymine DNA glycosylase (TDG) is a base excision repair (BER) enzyme, which is implicated in correction of deamination-induced DNA mismatches, the DNA demethylation process and regulation of gene expression. Because of these pivotal roles associated, it is crucial to elucidate how the TDG functions are appropriately regulated in vivo. Here, we present evidence that the TDG protein undergoes degradation upon various types of DNA damage, including ultraviolet light (UV). The UV-induced degradation of TDG was dependent on proficiency in nucleotide excision repair and on CRL4CDT2 -mediated ubiquitination that requires a physical interaction between TDG and DNA polymerase clamp PCNA. Using the Tdg-deficient mouse embryonic fibroblasts, we found that ectopic expression of TDG compromised cellular survival after UV irradiation and repair of UV-induced DNA lesions. These negative effects on cellular UV responses were alleviated by introducing mutations in TDG that impaired its BER function. The expression of TDG induced a large-scale alteration in the gene expression profile independently of its DNA glycosylase activity, whereas a subset of genes was affected by the catalytic activity of TDG. Our results indicate the presence of BER-dependent and BER-independent functions of TDG, which are involved in regulation of cellular DNA damage responses and gene expression patterns.

Sonographic sequential change of the anteroinferior labrum following arthroscopic Bankart repair: quantitative and qualitative assessment.

OBJECTIVE: Although arthroscopic Bankart repair is widely performed, little is known concerning the healing process of the Bankart lesion. This study aimed to describe the sonographic sequential change of the anteroinferior labrum following arthroscopic Bankart repair, both quantitatively and qualitatively. MATERIALS AND METHODS: Twenty-five subjects who had undergone arthroscopic Bankart repair were investigated using a sonographic diagnostic device equipped with shear-wave elastographic technology. In addition to measuring the elasticity of the anteroinferior labrum, the B-mode echogram of the anteroinferior labrum was classified into three grades based on the relative echogenicity. Assessment was performed in the affected shoulder 1, 2, 3, 4, 5, 6, and 12 months postoperatively and in the contralateral shoulder 1 month postoperatively for the control. RESULTS: The mean elasticity of the anteroinferior labrum in the affected shoulder 1 and 2 months postoperatively was significantly lower than in the contralateral shoulder (p < 0.001 for both). However, no significant difference was found after 3 months postoperatively. B-mode echograms of the anteroinferior labrum in the contralateral shoulder were classified as grade 0 in all subjects (100%), whereas the percentage of grade 0s in the affected shoulder was 0, 4, 96, and 100% at 1, 2, 3, and 4 months postoperatively. CONCLUSION: Both quantitative and qualitative assessment of repaired anteroinferior labrum using ultrasound became comparable with the contralateral shoulder 3-4 months postoperatively. Ultrasound is a useful decision-supporting tool to prescribe postoperative rehabilitation protocol following arthroscopic Bankart repair, although functional recovery should also be evaluated on an individual basis.

Dose and dose-rate effects of ionizing radiation: a discussion in the light of radiological protection.

The biological effects on humans of low-dose and low-dose-rate exposures to ionizing radiation have always been of major interest. The most recent concept as suggested by the International Commission on Radiological Protection (ICRP) is to extrapolate existing epidemiological data at high doses and dose rates down to low doses and low dose rates relevant to radiological protection, using the so-called dose and dose-rate effectiveness factor (DDREF). The present paper summarizes what was presented and discussed by experts from ICRP and Japan at a dedicated workshop on this topic held in May 2015 in Kyoto, Japan. This paper describes the historical development of the DDREF concept in light of emerging scientific evidence on dose and dose-rate effects, summarizes the conclusions recently drawn by a number of international organizations (e.g., BEIR VII, ICRP, SSK, UNSCEAR, and WHO), mentions current scientific efforts to obtain more data on low-dose and low-dose-rate effects at molecular, cellular, animal and human levels, and discusses future options that could be useful to improve and optimize the DDREF concept for the purpose of radiological protection.

A parental report of children's anxiety symptoms in Japan.

Using parental reports, the current study investigated anxiety symptoms among Japanese children as part of the process of developing the Japanese version of the Spence Children's Anxiety Scale for Parents (SCAS-P). The participants were 677 parents and children aged 9-12 years. Confirmatory factor analysis on 568 parents and children supported that the SCAS-P had a 6-factor structure. The scale showed satisfactory internal consistency and good convergent validity. A MANOVA indicated no significant gender or age differences except for the obsessive-compulsive disorder subscale. Among Japanese children, the most prevalent symptoms within the parental report were items related to fear of the dark and of insects/spiders. Finally, we observed very low correlations between parental and child reports of anxiety symptoms; the relationships between child and parental reports were rather poor among Japanese children. We briefly discuss the utility of the SCAS-P as a screening instrument assessing parental reports of anxiety symptoms.

Skin can control solar UVR-induced mutations through the epidermis-specific response of mutation induction suppression.

Skin exposure to solar ultraviolet radiation (UVR) has been a major public concern because of its genotoxicity. We established recently three action spectra of UVR biological effects using inflammation, mutagenicity, and mutation induction suppression (MIS) as indicators to evaluate UVR risk for mammalian skin. MIS is an antigenotoxic epidermis-specific response by which the increase of the mutant frequency (MF) levels off above a certain UVR dose. Here, based on these spectra, the mutation load of the skin after sunlight exposure was evaluated utilizing the spectral solar-UVR intensity data which had been measured at Tsukuba, Japan by the Japan Meteorological Agency. We estimated the daily variation of the solar-UVR effectiveness (effect per second) for the three indicators, and revealed that the effectiveness efficiency (effect per dose) of midday sunlight is 3-4-fold higher than those in the early morning and late afternoon. Based on the daily variations of mutagenicity and MIS effectiveness, we further estimated MFs induced after every one-hour sunlight exposure and reached a remarkable prediction that MFs should be suppressed to a constant level during 9:00-15:00 by MIS. The estimates agreed well with the equivalent values directly determined at Sendai, a site close to Tsukuba, although a small difference was detected for the epidermis at the dose range where the suppressed MFs were predicted. We propose the use of observed minimum inflammation/erythema doses to improve the difference. Our method could provide reliable estimates of sunlight genotoxicity to evaluate skin cancer probabilities.

Solar-UV-signature mutation prefers TCG to CCG: extrapolative consideration from UVA1-induced mutation spectra in mouse skin.

UVA1 exerts its genotoxicity on mammalian skin by producing cyclobutane pyrimidine dimers (CPDs) in DNA and preferentially inducing solar-UV-signature mutations, C → T base substitution mutations at methylated CpG-associated dipyrimidine (Py-mCpG) sites, as demonstrated previously using a 364 nm laser as a UVA1 source and lacZ-transgenic mice that utilize the transgene as a mutational reporter. In the present study, we confirmed that a broadband UVA1 source induced the same mutation profiles in mouse epidermis as the UVA1 laser, generalizing the previous result from a single 364 nm to a wider wavelength range of UVA1 (340-400 nm). Combined with our previous data on the mutation spectra induced in mouse epidermis by UVB, UVA2 and solar UVR, we proved that the solar-UV-signature mutation is commonly observed in the wavelength range from UVB to UVA, and found that UVA1 induces this mutation more preferentially than the other shorter wavelength ranges. This finding indicates that the solar-UV-signature mutation-causing CPDs, which are known to prefer Py-mCpG sites, could be produced with the energy provided by the longer wavelength region of UVR, suggesting a photochemical reaction through the excitation of pyrimidine bases to energy states that can be accomplished by absorption of even low-energy UVR. On the other hand, the lower proportions of solar-UV-signature mutations observed in the mutation spectra for UVB and solar UVR indicate that the direct photochemical reaction through excited singlet state of pyrimidine bases, which can be accomplished only by high-energy UVR, is also involved in the mutation induction at those shorter wavelengths of UVR. We also found that the solar-UV signature prefers 5'-TCG-3' to 5'-CCG-3' as mutational target sites, consistent with the fact that UVA induces CPDs selectively at thymine-containing dipyrimidine sites and that solar UVR induces them preferably at Py-mCpG sites. However, the mutation spectrum in human p53 gene from non-melanoma skin cancers shows the opposite preference for 5'-CCG-3' sites. This apparent discrepancy in the site preference seems to result from the lack of 5'-TCG-3' sites mutable to missense mutations on the nontranscribed strand of human p53 gene, which should be evolutionally acquired under selective pressure from the sun.

Fully functional global genome repair of (6-4) photoproducts and compromised transcription-coupled repair of cyclobutane pyrimidine dimers in condensed mitotic chromatin.

During mitosis, chromatin is highly condensed, and activities such as transcription and semiconservative replication do not occur. Consequently, the condensed condition of mitotic chromatin is assumed to inhibit DNA metabolism by impeding the access of DNA-transacting proteins. However, about 40 years ago, several researchers observed unscheduled DNA synthesis in UV-irradiated mitotic chromosomes, suggesting the presence of excision repair. We re-examined this subject by directly measuring the removal of UV-induced DNA lesions by an ELISA and by a Southern-based technique in HeLa cells arrested at mitosis. We observed that the removal of (6-4) photoproducts from the overall genome in mitotic cells was as efficient as in interphase cells. This suggests that global genome repair of (6-4) photoproducts is fully functional during mitosis, and that the DNA in mitotic chromatin is accessible to proteins involved in this mode of DNA repair. Nevertheless, not all modes of DNA repair seem fully functional during mitosis. We also observed that the removal of cyclobutane pyrimidine dimers from the dihydrofolate reductase and c-MYC genes in mitotic cells was very slow. This suggests that transcription-coupled repair of cyclobutane pyrimidine dimers is compromised or non-functional during mitosis, which is probably the consequence of mitotic transcriptional repression.

Septic pulmonary embolism induced by dental infection.

Dental infection can be an important source for septic pulmonary embolism (SPE), but only a few cases of SPE accompanying dental infection have been reported. The aim of this study was to characterize the clinical features of SPE induced by dental infection. Patients who fulfilled the diagnostic criteria described in the text were recruited in a retrospective fashion. All 9 patients were men, with a median age of 59 years (range:47 to 74 years). Eight patients had chest pain (88.9%), 5 had a preceding toothache (55.6%) and 3 had preceding gingival swelling (33.3%). Blood cultures obtained from 7 patients were negative. Periodontitis was found in all of the cases, periapical periodontitis in 5 cases, and gingival abscess in 3 cases. The median duration of hospitalization was 15 days, and symptoms were mild in some cases. In addition to antimicrobial therapy, tooth extraction was performed in 3 cases, tooth scaling in 6. SPE induced by dental infection has prominent clinical characteristics such as male preponderance, chest pain, preceding toothache, and mild clinical course.

[Electrochemical Analysis Using Organic Nitroxyl Radicals].

Organic nitroxyl radicals represented by 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) are known to be compounds that catalyze alcohol oxidation reactions. These catalytic reactions can be applied to a wide range of compounds with hydroxy and amino groups. It is also possible to selectively oxidize primary alcohols by designing the skeleton around the nitroxyl radical moiety for use in organic synthesis. Reactions can also be carried out by electrochemical methods, and the electrical current measured during the reaction can be used to quantify the substrates. Therefore, the combination of reactions catalyzed by nitroxyl radicals and electrochemical techniques is expected to be applied as a new analytical method. However, since the reaction does not proceed rapidly in neutral aqueous solutions, it has mostly been applied in basic aqueous solutions or organic solvents, and there have been no reports on sensor applications under physiological conditions. Herein, we have developed a novel catalyst, nortropine N-oxyl (NNO), which is highly active even in neutral aqueous solutions, and have found that it can be used for the analysis of biological components and drugs under physiological conditions. The combination of this method with enzymatic reactions made it possible to specifically detect certain compounds. In this review, we describe a novel analytical method that combines these nitroxyl radicals with electrochemical methods.

Determination of antibiotics by amperometry using nortropine N-oxyl, a highly active nitroxyl radical.

Nitroxyl radical compounds oxidize hydroxy groups and some amino groups upon application of an electric potential. The resulting anodic current depends on the concentration of these functional groups in solution. Thus, it is possible to quantify compounds containing these functional groups by electrochemical methods. Cyclic voltammetry has been used to evaluate the catalytic activity of nitroxyl radicals, and the ability of such radicals to sense biological and other compounds. In this study, we evaluated a method for quantifying compounds using constant-potential electrolysis (amperometry) of nitroxyl radicals for application in flow injection analysis and high-performance liquid chromatography as an electrochemical detector. When amperometry was performed using 2,2,6,6-tetramethylpiperidine 1-oxyl, a common nitroxyl radical compound, little change was observed even with 100 mM glucose due to its low reactivity in neutral aqueous solutions. In contrast, 2-azaadamantane N-oxyl and nortropine N-oxyl, which are highly active nitroxyl radicals, showed a concentration-dependent response in neutral aqueous solution. Responses of 33.8 and 125.9 µA, respectively, were observed. By recognition of hydroxy and amino groups, we have succeeded in the electrochemical detection of some drugs by amperometry. Streptomycin, an aminoglycoside antibiotic, was quantifiable in the range of 30-1000 µM.

Electrochemical reactions of highly active nitroxyl radicals with thiol compounds.

Nitroxyl radicals are known to electrochemically oxidize thiols as well as alcohols and amines. In this study, a preliminary investigation of the electrochemical reaction of thiols with 9-azabicyclo[3.3.1]nonane N-oxyl (ABNO), 2-azaadamantane N-oxyl (AZADO), and nortropine N-oxyl (NNO), which are highly active due to their bicyclo structures, for use in electrochemical analysis was performed and the results were compared with those for a typical nitroxyl radical compound, 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO). Mercaptopropane sulfonic acid (MPS) was used as a model compound to investigate the electrochemical response in aqueous solution. In addition, electrochemical detection of glutathione, a biological thiol molecule, was performed.

Functional interactions between BLM and XRCC3 in the cell.

Bloom's syndrome (BS), which is caused by mutations in the BLM gene, is characterized by a predisposition to a wide variety of cancers. BS cells exhibit elevated frequencies of sister chromatid exchanges (SCEs), interchanges between homologous chromosomes (mitotic chiasmata), and sensitivity to several DNA-damaging agents. To address the mechanism that confers these phenotypes in BS cells, we characterize a series of double and triple mutants with mutations in BLM and in other genes involved in repair pathways. We found that XRCC3 activity generates substrates that cause the elevated SCE in blm cells and that BLM with DNA topoisomerase IIIalpha suppresses the formation of SCE. In addition, XRCC3 activity also generates the ultraviolet (UV)- and methyl methanesulfonate (MMS)-induced mitotic chiasmata. Moreover, disruption of XRCC3 suppresses MMS and UV sensitivity and the MMS- and UV-induced chromosomal aberrations of blm cells, indicating that BLM acts downstream of XRCC3.

Role of the Msh2 gene in genome maintenance and development in mouse fetuses.

In an attempt to evaluate the roles of the mismatch repair gene Msh2 in genome maintenance and in development during the fetal stage, spontaneous mutations and several developmental indices were studied in Msh2-deficient lacZ-transgenic mouse fetuses. Mutation levels in fetuses were elevated at 9.5 dpc (days post coitum) when compared to wild-type mice, and the level of mutations continued to increase until the fetuses reached the newborn stage. The mutation levels in 4 different tissues of newborns showed similar magnitudes to those in the whole body. The levels remained similar after birth until 6 months of age. The molecular nature of the mutations examined in 12.5 dpc fetuses of Msh2(+/+) and Msh2(-/-) revealed unique spectra which reflect errors produced during the DNA replication process, and those corrected by a mismatch repair system. Most base substitutions and simple deletions were reduced by the presence of the Msh2 gene, whereas G:C to A:T changes at CpG sequences were not affected, suggesting that the latter change was not influenced by mismatch repair. On the other hand, analysis of developmental indices revealed that there was very little effect, including the presence of malformations, resulting from Msh2-deficiencies. These results indicate that elevated mutation levels have little effect on the development of the fetus, even if a mutator phenotype appears at the organogenesis stage.

Embryonic lethality in mice lacking mismatch-specific thymine DNA glycosylase is partially prevented by DOPS, a precursor of noradrenaline.

Thymine DNA glycosylase (TDG) is involved in the repair of G:T and G:U mismatches caused by hydrolytic deamination of 5-methylcytosine and cytosine, respectively. Recent studies have shown that TDG not only has G-T/U glycosylase activities but also acts in the maintaining proper epigenetic status. In order to investigate the function of TDG in vivo, mice lacking Tdg, Tdg (-/-), were generated. Tdg mutant mice died in utero by 11.5 days post coitum (dpc), although there were no significant differences in the spontaneous mutant frequencies between wild type and Tdg (-/-) embryos. On the other hand, the levels of noradrenaline in 10.5 dpc whole embryos, which is necessary for normal embryogenesis, were dramatically reduced in Tdg (-/-) embryos. Consequently, we tested the effect of D, L-threo-3, 4-dihydroxyphenylserine (DOPS), a synthetic precursor of noradrenaline, on the survival of the Tdg (-/-) embryos. DOPS was given to pregnant Tdg (+/-) mice from 6.5 dpc through drinking water. Most of the Tdg (-/-) embryos were alive at 11.5 dpc, and they were partially rescued up to 14.5 dpc by the administration of DOPS. In contrast, the administration of L-3, 4-dihydroxyphenylalanine (L-DOPA) had marginal effects on Tdg (-/-) embryonic lethality. No embryo was alive without DOPS beyond 11.5 dpc, suggesting that the lethality in (-/-) embryos is partially due to the reduction of noradrenaline. These results suggest that embryonic lethality in Tdg (-/-) embryos is due, in part, to the reduction of noradrenaline levels.

Electrical Stimuli-Responsive Decomposition of Layer-by-Layer Films Composed of Polycations and TEMPO-Modified Poly(acrylic acid).

We previously reported that layer-by-layer (LbL) film prepared by a combination of 2,2,6,6-tetramethylpiperidinyl N-oxyl (TEMPO)-modified polyacrylic acid (PAA) and polyethyleneimine (PEI) were decomposed by application of an electric potential. However, there have been no reports yet for other polycationic species. In this study, LbL films were prepared by combining various polycationics (PEI, poly(allylamine hydrochloride) (PAH), poly(diallydimethylammonium chloride) (PDDA), and polyamidoamine (PAMAM) dendrimer) and TEMPO-PAA, and the decomposition of the thin films was evaluated using cyclic voltammetry (CV) and constant potential using an electrochemical quartz crystal microbalance (eQCM). When a potential was applied to an electrode coated on an LbL thin film of polycations and TEMPO-PAA, an oxidation potential peak (Epa) was obtained around +0.6 V vs. Ag/AgCl in CV measurements. EQCM measurements showed the decomposition of the LbL films at voltages near the Epa of the TEMPO residues. Decomposition rate was 82% for the (PEI/TEMPO-PAA)5 film, 52% for the (PAH/TEMPO-PAA)5 film, and 49% for the (PDDA/TEMPO-PAA)5 film. It is considered that the oxoammonium ion has a positive charge, and the LbL films were decomposed due to electrostatic repulsion with the polycations (PEI, PAH, and PDDA). These LbL films may lead to applications in drug release by electrical stimulation. On the other hand, the CV of the (PAMAM/TEMPO-PAA)5 film did not decompose. It is possible that the decomposition of the thin film is not promoted, probably because the amount of TEMPO-PAA absorbed is small.

A case of mediastinal lymph node carcinoma of unknown primary site treated with docetaxel and cisplatin with concurrent thoracic radiation therapy.

Mediastinal lymph node carcinoma of unknown primary site is rare and may have a better prognosis if extensive treatment is performed. Case, A 69-year-old-male presented with a persistent cough. Chest computed tomography (CT) demonstrated a large tumor 9.5 × 8.2 cm, in the mediastinum, compressing the right main bronchus, the right pulmonary artery, and the superior vena cava. Because fiberoptic bronchoscopy was insufficient for diagnosis, mediastinoscopic tumor biopsy under general anesthesia was undertaken. Histological examination revealed adenocarcinoma. Extensive examinations revealed no other neoplastic lesion except in the mediastinum. Mediastinal lymph node carcinoma of unknown primary site was diagnosed. The patient was treated with docetaxel and cisplatin with concurrent thoracic radiation therapy. A month after the start of chemoradiotherapy, the mediastinal tumor regressed markedly. The patient remained free of symptoms without regrowth of the primary site. Exploration of the body showed no further abnormalities 20 months after disease onset.

Voltammetric response of ferroceneboronic acid to diol and phenolic compounds as possible pollutants.

A voltammetric determination of possible organic pollutants such as diol and phenolic compounds in water was studied using ferroceneboronic acid (FBA) as a redox-active marker. A cyclic voltammogram of FBA exhibited a pair of oxidation and reduction peaks at 230 and 170 mV at pH 7.0, respectively, while another pair of redox peaks was observed in the presence of diol or phenolic compounds tested. The results were rationalized based on the formation of boronate esters of FBA with the added compounds. The changes in the redox peak currents were dependent on the concentration of the additives, suggesting a usefulness of FBA in the electrochemical determination of these compounds in water.

Chemical reduction of Ag+ to Ag employing organic electron donors: evaluation of the effect of Ag+-mediated cytosine-cytosine base pairing on the aggregation of Ag nanoparticles.

Ag+-mediated base pairing is valuable for synthesising DNA-based silver nanoparticles (AgNPs) and nanoclusters (AgNCs). Recently, we reported the formation of a [Ag(cytidine)2]+ complex in dimethyl sulfoxide (DMSO), which facilitated the evaluation of the effect of cytosine-Ag+-cytosine (C-Ag+-C) base pairing on the degree of AgNP aggregation in solution. As an aprotic solvent, DMSO was expected to dissolve the [Ag(cytidine)2]+ complex, and powerful reducing agents, such as organic electron donors. In this study, the chemical reduction of a cytidine/Ag+ system using a powerful reducing agent tetrakis(dimethylamino)ethylene (TDAE) was investigated. 1H/13C/15N NMR spectroscopic evidence was obtained to identify the iminium dication (TDAE2+), which is an oxidised form of TDAE. The results were compared with those obtained using another organic electron donor, tetrathiafulvalene (TTF), which exhibits a relatively lower reduction activity than TDAE. AgNPs prepared via redox reaction between [Ag(cytidine)2]+ and organic electron donors (TDAE and TTF) were characterised using UV-Vis spectroscopy and nanoparticle tracking analysis. It was found that the formation of C-Ag+-C base pairing inhibited the aggregation of AgNPs in solution. In addition, in the presence of cytidine, the total concentration of the AgNP solution was affected by the reduction activity of the reducing agent.