High-dimensional single photon based quantum secure direct communication using time and phase mode degrees

Quantum secure direct communication (QSDC) can guarantee security using the characteristics of quantum mechanics even when a message is directly transmitted through a quantum channel without using a secret key. However, the transmission rate of the QSDC is limited by the dead time of a single photon detector (SPD) as well as channel loss over the distance. To overcome this limited transmission rate, we propose a high-dimensional single photon-based QSDC protocol that applies two optical degrees of freedom: time and phase state. First, an N-dimensional time and phase state generation method that considers the dead time is proposed to minimize the measurement loss of a transmitted message. Second, among the two types of quantum states, the phase state with relatively low measurement efficiency is used only for eavesdropping detection, and the time state is used for sending messages with differential delay time bin-based encoding techniques. Lastly, we propose an efficient method for measuring N-dimensional time and phase-based quantum states and recovering classical bit information. This study performs security analysis against various attacks, and verifies the transmission rate improvement effect through simulation. The result indicates that our proposal can guarantee higher security and transmission rates compared to the conventional DL04 QSDC.

EFFECTS OF EVEN FUNCTIONAL GROUP DISTRIBUTION IN EMULSION STYRENE–BUTADIENE RUBBER PREPARED BY REVERSIBLE ADDITION–FRAGMENTATION CHAIN TRANSFER POLYMERIZATION ON THE PROPERTIES OF SILICA-FILLED COMPOUNDS

Recently, considerable attention has been paid to the development of new functionalized polymers to improve the fuel efficiency of vehicles by reducing the rolling resistance of tires to adhere to strict CO2 emission regulations. Accordingly, multifunctionalized (MF) reversible addition–fragmentation chain transfer (RAFT) emulsion styrene–butadiene rubbers (ESBR) were synthesized, in which chain-end and in-chain functionalization were performed simultaneously by introducing a third monomer (glycidyl methacrylate; GMA) using RAFT polymerization. Compared with GMA ESBR, in which GMA is introduced as a third monomer by conventional radical polymerization (CRP), there was an even distribution of GMA per chain in the MF-RAFT ESBR. After preparing the silica-filled compounds, vulcanizate structure analysis and mechanical property evaluation of the compounds were performed. The MF-RAFT ESBR prepared by RAFT polymerization exhibited superior in-chain functionalization efficiency compared with GMA ESBR prepared by CRP because of the even distribution of GMA and higher crosslink density. Consequently, MF-RAFT ESBR compound showed superior silica dispersion, abrasion resistance, and lower rolling resistance compared with the GMA ESBR compound.

Development of a high-resolution typing method for SLA-3, swine MHC class I antigen 3

We developed a high-resolution and comprehensive typing method for swine leukocyte antigen 3 (SLA-3), an MHC class I gene, employing locus-specific genomic PCR followed by subsequent direct sequencing. A total of 292 individuals from nine pure, one cross-breed and six cell lines were successfully typed. A total of 21 SLA-3 alleles were identified, of which four were found to be novel alleles. However, the allelic diversity of SLA-3 was lower than that of previously reported class I genes, SLA-1 and -2. More SLA-3 alleles were observed in the Landrace and Yorkshire breeds than the other breeds. SLA-3*04:01 was identified in seven out of nine breeds and was the most widely distributed allele across all breeds. Therefore, the typing method reported in this study completes our efforts to develop high-resolution typing methods for major SLA molecules, facilitating the combined analysis of major SLA genes from field samples, which is important to understand the relationship between the adaptive immune responses against pathogens and the immunogenetic makeup of an individual.

Effect of Epoxide Content on the Vulcanizate Structure of Silica-Filled Epoxidized Natural Rubber (ENR) Compounds

The demand for truck-bus radial (TBR) tires with enhanced fuel efficiency has grown in recent years. Many studies have investigated silica-filled natural rubber (NR) compounds to address these needs. However, silica-filled compounds offer inferior abrasion resistance compared to carbon black-filled compounds. Further, the use of NR as a base rubber can hinder silanization and coupling reactions due to interference by proteins and lipids. Improved silica dispersion be achieved without the use of a silane coupling agent by introducing epoxide groups to NR, which serve as silica-affinitive functional groups. Furthermore, the coupling reaction can be promoted by facilitating chemical interaction between the hydroxyl group of silica and the added epoxide groups. Thus, this study evaluated the properties of commercialized NR, ENR-25, and ENR-50 compounds with or without an added silane coupling agent, and the filler-rubber interaction was quantitatively calculated using vulcanizate structure analysis. The increased epoxide content, when the silane coupling agent was not used, improved silica dispersion, abrasion resistance, fuel efficiency, and wet grip. Once a basic level of silica dispersion was secured by using the silane coupling agent, both the abrasion resistance and wet grip improved with increasing epoxide content. Furthermore, the silane coupling agent could be partially replaced by ENR due to the high filler-rubber interaction between the ENR and silica. Therefore, epoxidation shows potential for resolving the issues associated with poor coupling reactions and abrasion resistance in silica-filled NR compounds.

Effects of Molecular Weight of Functionalized Liquid Butadiene Rubber as a Processing Aid on the Properties of SSBR/Silica Compounds

Liquid butadiene rubber (LqBR) which used as a processing aid play a vital role in the manufacturing of high-performance tire tread compounds. However, the studies on the effect of molecular weight, microstructure, and functionalization of LqBR on the properties of compounds are still insufficient. In this study, non-functionalized and center-functionalized liquid butadiene rubbers (N-LqBR and C-LqBR modified with ethoxysilyl group, respectively) were synthesized with low vinyl content and different molecular weights using anionic polymerization. In addition, LqBR was added to the silica-filled SSBR compounds as an alternative to treated distillate aromatic extract (TDAE) oil, and the effect of molecular weight and functionalization on the properties of the silica-filled SSBR compound was examined. C-LqBR showed a low Payne effect and Mooney viscosity because of improved silica dispersion due to the ethoxysilyl functional group. Furthermore, C-LqBR showed an increased crosslink density, improved mechanical properties, and reduced organic matter extraction compared to the N-LqBR compound. LqBR reduced the glass transition temperature (T_g) of the compound significantly, thereby improving snow traction and abrasion resistance compared to TDAE oil. Furthermore, the energy loss characteristics revealed that the hysteresis loss attributable to the free chain ends of LqBR was dominant.

Vulcanizate Structures of SBR Compounds with Silica and Carbon Black Binary Filler Systems at Different Curing Temperatures

The tire industry has shown an increasing demand for the reduction in rolling resistance. Efforts have been made to improve the viscoelastic properties of tire compounds and reduce the weight of tires through optimization of the vulcanizate structure, which has become extremely complex. In this study, vulcanizates using carbon black and silica as binary fillers were prepared at various curing temperatures. Vulcanizate structures with respect to curing temperature were classified according to the chemical crosslink density by sulfur, carbon black bound rubber (i.e., physical crosslink due to carbon black), and silica-silane-rubber network. All properties exhibited a decreasing trend under the application of high curing temperatures, and the decrease in the crosslink density per unit content of filler with an increase in curing temperature was shown to be greater in carbon black than in silica. Mechanical and viscoelastic properties were also measured to evaluate the impact that the compound variates have on tire tread performance. These results serve as a guideline for determining the content and filler type and for setting the cure condition during the design of actual compound formulations to increase the crosslink density of rubber while retaining the necessary mechanical and viscoelastic properties for practical application.

VULCANIZATE STRUCTURES AND MECHANICAL PROPERTIES OF RUBBER COMPOUNDS WITH SILICA AND CARBON BLACK BINARY FILLER SYSTEMS

The physical properties of rubber compounds are mainly determined by the filler dispersion within the rubber matrix, filler–rubber interaction, and chemical crosslink structure caused by sulfur. Carbon black or silica is typically used as a reinforcing filler in tire tread compounds; however, binary filler systems comprising the two types of filler are also currently being used to complement each other. This study used binary filler systems to manufacture vulcanizates and classified the vulcanizate structures as chemical crosslinks caused by sulfur, physical crosslinks caused by carbon black (carbon black–bound rubber), and silica–silane–rubber networks caused by silica and silane. The effect of each vulcanizate structure on the physical properties was also calculated. In the proposed binary filler system, silica chemically bonds with rubber molecules, unlike carbon black. Therefore, the crosslink density per unit of silica content was 19% higher than that of carbon black, in which rubber molecules were physically adsorbed on the surface. Tensile properties affected by 1 unit of crosslinking density for each filler were calculated, and silica was found to contribute more in the low-elongation range, whereas carbon black contributed more in the high-elongation range. Regarding tan δ at 60 °C and abrasion resistance per unit crosslink density of filler, carbon black made a greater contribution than silica, whereas silica had a greater contribution to wet traction and snow traction.

EFFECTS OF SILANE AGENTS AND CURING TEMPERATURES ON VULCANIZATE STRUCTURES

Silane coupling agents are commonly used in silica-filled rubber compounds to hydrophobize the silica surface and improve filler–rubber interaction. The coupling agent bis[3-(triethoxysilyl)propyl]tetrasulfide (TESPT) is the most widely used coupling agent. The tetrasulfide is more reactive than the disulfide in bis[3-(triethoxysilyl)propyl]disulfide (TESPD) due to its low decomposition energy, resulting in more coupling reaction with rubber molecules. Meanwhile, vulcanization temperature affects chemical networks. Polysulfide is vulnerable to heat, so it can be easily broken to form shorter crosslinks. Compounds with TESPD or TESPT were vulcanized at 160 and 180 °C. In addition to the decomposition, the reactivity of the silanes was confirmed from the cure characteristics of the compounds without the curatives. TESPD could also cause a coupling reaction without the curatives such as TESPT known to release free sulfur. By analyzing vulcanizate structures, total crosslink density was separated into chemical crosslink density and filler–rubber networks. Applying TESPT or vulcanizing at 180 °C increased the filler–rubber networks, and the higher vulcanization temperature decreased the chemical crosslink density. By correlating physical properties, effects of the vulcanizate structures on performance of tread compounds were investigated. The filler–rubber interaction was dominant for wet traction and mechanical properties in tensile test. The chemical crosslink density affected rolling resistance.

INFLUENCE OF END-FUNCTIONALIZED SOLUTION STYRENE–BUTADIENE RUBBER ON SILICA-FILLED VULCANIZATES WITH VARIOUS SILICA–SILANE SYSTEMS

We investigated how end-functionalized solution styrene–butadiene rubber (SSBR) affects the vulcanizate structures and the physical properties of silica-filled vulcanizates using non-functionalized and end-functionalized SSBRs with aminopropylalkoxysilane. Two silane agents were used. Triethoxy(octyl)silane was used as a covering agent, and bis-[3-(triethoxysilyl)propyl]disulfide was applied as a coupling agent. The effects of three different silica–silane systems with a covering agent (CV), a coupling agent (CP), or with no silane (NS) were analyzed. In the CV and NS systems, the cross-link densities induced by the polymer and curing system were similar with respect to the end-functionalization. Further, the cross-link densities induced by the silica–silane system were similar, regardless of the end-functionalization. However, the CP system exhibited similar cross-link densities, irrespective of functionalization. Both the coupling agent and end-functional group chemically bonded with the silanol groups of silica, thus competing with each other and affecting the vulcanizate structure. However, increasing the silica content decreased the effect of end-functionalization because the content of the coupling agent increased, and the end-functional group was less mobile than the coupling agent's alkoxy group.

Effect of Calcium Chloride as a Coagulant on the Properties of ESBR/Silica Wet Masterbatch Compound

When designing rubber compounds for high-performance tires, increasing the silica content can improve the wet traction performance but decreases the fuel efficiency. This trade-off relation makes it difficult to improve the two factors simultaneously. One approach is the development of silica wet masterbatch (WMB) technology for producing compounds containing a high silica content with good dispersion. The technology involves a step to mix surface-modified silica and rubber latex. The technique requires a coagulant to break up the micelles of the rubber latex and cause the surface-modified silica and the rubber molecules to co-coagulate due to van der Waals forces. In this study, the effect of coagulant type on the characteristics of silica surface, and the mechanical properties of the emulsion styrene-butadiene rubber (ESBR)/silica WMB compounds was investigated, as well as the abrasion properties and the viscoelastic properties of the vulcanizates.

Attosecond nanoscale near-field sampling

The promise of ultrafast light-field-driven electronic nanocircuits has stimulated the development of the new research field of attosecond nanophysics. An essential prerequisite for advancing this new area is the ability to characterize optical near fields from light interaction with nanostructures, with sub-cycle resolution. Here we experimentally demonstrate attosecond near-field retrieval for a tapered gold nanowire. By comparison of the results to those obtained from noble gas experiments and trajectory simulations, the spectral response of the nanotaper near field arising from laser excitation can be extracted.

Photoemission from nanometre-scale structures offer a route toward ultrafast light-field-driven electronic nanocircuits. Here, the authors use attosecond streaking spectroscopy for nanoscale characterization of near-fields in the vicinity of tapered gold nanowires.

Optimization of a nanotip on a surface for the ultrafast probing of propagating surface plasmons

We theoretically analyze a method for characterizing propagating surface plasmon polaritons (SPPs) on a thin gold film. The SPPs are excited by few-cycle near-infrared pulses using Kretschmann coupling, and a nanotip is used as a local field sensor. This geometry removes the influence of the incident excitation laser from the near fields, and enhances the plasmon electric field strength. Using finite-difference-time-domain studies we show that the geometry can be used to measure SPP waveforms as a function of propagation distance. The effects of the nanotip shape and material on the field enhancement and plasmonic response are discussed.

Field propagation-induced directionality of carrier-envelope phase-controlled photoemission from nanospheres

Near-fields of non-resonantly laser-excited nanostructures enable strong localization of ultrashort light fields and have opened novel routes to fundamentally modify and control electronic strong-field processes. Harnessing spatiotemporally tunable near-fields for the steering of sub-cycle electron dynamics may enable ultrafast optoelectronic devices and unprecedented control in the generation of attosecond electron and photon pulses. Here we utilize unsupported sub-wavelength dielectric nanospheres to generate near-fields with adjustable structure and study the resulting strong-field dynamics via photoelectron imaging. We demonstrate field propagation-induced tunability of the emission direction of fast recollision electrons up to a regime, where nonlinear charge interaction effects become dominant in the acceleration process. Our analysis supports that the timing of the recollision process remains controllable with attosecond resolution by the carrier-envelope phase, indicating the possibility to expand near-field-mediated control far into the realm of high-field phenomena.

The localized enhancement of laser light in optical near-fields of nanostructures enables the steering of ultrafast electronic motion. Here, the authors employ field propagation in nanospheres to obtain directional tunability and attosecond control of near-field-induced strong-field photoemission.

Coherent electronic wave packet motion in C(60) controlled by the waveform and polarization of few-cycle laser fields

Strong laser fields can be used to trigger an ultrafast molecular response that involves electronic excitation and ionization dynamics. Here, we report on the experimental control of the spatial localization of the electronic excitation in the C_{60} fullerene exerted by an intense few-cycle (4 fs) pulse at 720 nm. The control is achieved by tailoring the carrier-envelope phase and the polarization of the laser pulse. We find that the maxima and minima of the photoemission-asymmetry parameter along the laser-polarization axis are synchronized with the localization of the coherent electronic wave packet at around the time of ionization.

Cancer cachexia decreases specific force and accelerates fatigue in limb muscle

Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative soleus is also important for normal locomotion, we further performed a fatigue trial in the soleus and found that the decrease in relative force was greater and more rapid in solei from C-26 mice compared to controls. These data demonstrate that severe cancer cachexia causes profound muscle weakness that is not entirely explained by the muscle atrophy. In addition, cancer cachexia decreases the fatigue resistance of the soleus muscle, a postural muscle typically resistant to fatigue. Thus, specifically targeting contractile dysfunction represents an additional means to counter muscle weakness in cancer cachexia, in addition to targeting the prevention of muscle atrophy.

The benzoxathiolone LYR-71 down-regulates interferon-gamma-inducible pro-inflammatory genes by uncoupling tyrosine phosphorylation of STAT-1 in macrophages

BACKGROUND AND PURPOSE

Benzoxathiolone derivatives have shown anti-inflammatory and immunomodulatory potential in acne and psoriatic disorders. However, little is known about the molecular basis for these pharmacological effects. In this study, we decided to investigate the anti-inflammatory actions of a benzoxathiolone derivative LYR-71, 6-methyl-2-propylimino-6,7-dihydro-5H-benzo[1,3]oxathiol-4-one, in interferon (IFN)-gamma-activated macrophages.

EXPERIMENTAL APPROACH

RAW 264.7 macrophages or primary macrophages, derived from bone marrow of C3H/HeJ mice, were stimulated with IFN-gamma in the presence of LYR-71. Nitric oxide (NO) or chemokine production was measured by Griess reaction or enzyme-linked immunosorbent assay. RAW 264.7 cells were used to examine the molecular mechanisms of LYR-71 in modulating IFN-gamma-induced inflammatory responses.

KEY RESULTS

LYR-71 down-regulated IFN-gamma-induced transcription of inducible NO synthase, IFN-gamma-inducible protein-10 and the monokine induced by IFN-gamma genes in macrophages. This effect was mediated by uncoupling tyrosine phosphorylation of the signal transducer and activator of transcription (STAT)-1 in response to IFN-gamma. LYR-71 directly inhibited the in vitro catalytic activity of Janus kinase (JAK)-2. Further, the inhibitory actions of LYR-71 on IFN-gamma-induced STAT-1 phosphorylation and NO production were consistently abolished in the presence of peroxyvanadate, implying another target dependent on protein tyrosine phosphatase.

CONCLUSIONS AND IMPLICATIONS

Taken together, LYR-71 could restrain IFN-gamma-induced inflammatory responses through uncoupling the tyrosine phosphorylation of STAT-1, an activation index of JAK-STAT-1 signalling, in macrophages. These results may provide a molecular mechanism underlying anti-inflammatory actions shown by benzoxathiolone derivatives.

Molecular Monitoring of Wild-Type and Genetically Engineered Colletotrichum coccodes Biocontrol Strains In Planta

Two strains of Colletotrichum coccodes, the wild type (DAOM 183088) and T-20a, engineered with the necrosis- and ethylene-inducing peptide (NEP1) gene for hypervirulence on velvetleaf (Abutilon theophrasti, Medik.), were monitored in planta for the first 2 weeks after infection. Real-time quantitative polymerase chain reaction (QPCR) was used to assess the extent of colonization of both strains on velvetleaf using SYBR Green chemistry. Quantification of both strains was successful as soon as the conidia were sprayed on the leaves and up to 14 days after infection. The increase in fungal DNA amounts corroborated with the appearance of necrotic lesions on velvetleaf leaves infected with the wild-type strain. The wild-type C. coccodes was more efficient at infecting velvetleaf than the transgenic T-20a strain. In addition, detection of host DNA allowed us to quantitatively monitor the decrease in plant DNA amounts in response to wild-type strain infection. Expression of the NEP1 transgene by conventional retro-transcription (RT)-PCR was absent from T-20a growing on either V8 agar or in planta, suggesting that the gene may be silenced. The application of QPCR to monitor fungal growth was proven to detect the target organisms in planta prior to the appearance of symptoms.

Decreased Helicobacter pylori associated gastric carcinogenesis in mice lacking inducible nitric oxide synthase

BACKGROUND AND AIMS

Overproduction of nitric oxide via inducible nitric oxide synthase (iNOS) is suggested to be a significant pathogenic factor in Helicobacter pylori induced gastritis. The purpose of this study was to examine the role of iNOS in H pylori associated gastric carcinogenesis.

METHODS

Two types of mice were used in this study: iNOS deficient mice (iNOS-/-) and wild-type littermates. Gastric cancer was generated in mice using a combination treatment comprising N-methyl-N-nitrosourea administration and H pylori infection. Fifty weeks after treatment, tumours in gastric tissues from both types of mice were examined using histopathology, immunohistochemistry, and immunoblotting for iNOS and 3-nitrotyrosine.

RESULTS

The overall incidence of gastric cancer at week 50 was significantly lower in iNOS-/- compared with iNOS wild-type mice (p<0.05). When analysed according to tumour pathology, the incidence of gastric adenocarcinoma was significantly lower in iNOS-/- compared with iNOS wild-type mice (p<0.05). Immunostaining for iNOS was clearly observed in adenocarcinoma cells of iNOS wild-type mice, and was characterised by a strong cytoplasmic expression pattern. 3-Nitrotyrosine was expressed mostly in the area of the lamina propria of gastritis and adenoma lesions in iNOS wild-type mice. Immunoblotting analyses showed that iNOS and 3-nitrotyrosine were also expressed in both adenoma and adenocarcinoma tissues from iNOS wild-type mice. iNOS and 3-nitrotyrosine expression was greater in tumour tissues than in non-tumour tissues.

CONCLUSIONS

These findings suggest that iNOS contributes to H pylori associated gastric carcinogenesis in mice.

Clinical experience of e-PTFE membrane implant surgery for refractory glaucoma

AIMS

To evaluate the clinical efficacy of membrane tube implant made of expanded polytetrafluoroethylene (e-PTFE, Gore-Tex) membrane and silicone tube in treating refractory glaucoma.

METHODS

A retrospective chart review was performed on 43 eyes of 40 patients who underwent glaucoma tube shunt implant surgery using double layered e-PTFE membrane and silicone tube to treat refractory glaucoma. The surgeries were performed from May 1991 to September 1995, and the subjects were patients with terminal glaucoma without useful vision on the study eye.

RESULTS

The mean follow up period was 32.9 months. The Kaplan-Meier survival for intraocular pressure (IOP) control (IOP between 6 and 21mm Hg without significant complication) was 80.9% at 1 year, 73.9% at 2 years, and 62.2% at 3 years after surgery. After excluding three eyes of three patients who were dropped within 3 months after surgery and did not have any serious complication or problem in IOP control, the average preoperative IOP was 42.5 (SD 14.6) mm Hg and IOP on the last visit was 17.3 (10.2) mm Hg (p = 0.000, n = 40). The number of antiglaucoma medications before surgery (2.2 (0.6)) was reduced to 0.5 (0.8) on the last visit (p = 0.000). The IOP was controlled within the range of 6-21 mm Hg in 26 eyes (65.0%). In the remaining 14 eyes (35%), we could not control the IOP or additional surgery was needed to control the IOP or to treat severe complications. Two cases of endophthalmitis and three of phthisis were found as serious complications. The other complications were similar to those of other commercially available glaucoma implants.

CONCLUSION

A comparable clinical result was obtained with this new implant as with the other commercially available implants. This implant with a thin and non-rigid reservoir has a potential to reduce some complications associated with the large volume and rigid consistency of the other implants, although it is not yet proved. This membrane tube implant may be considered as another substitute in the surgery of refractory glaucoma.

Suppression of intestinal polyposis in Apc(Min/+) mice by inhibiting nitric oxide production

Inducible nitric oxide synthase (iNOS) was shown to be expressed in normal mucosa and adenoma of small and large intestines of Apc(Min/+) mice by reverse transcription-PCR and immunohistochemistry. Administration of the iNOS inhibitor aminoguanidine (1.5 g/liter) in drinking water or an L-arginine-deficient diet to Apc(Min/+) mice resulted in a significant decrease in adenoma development in the small but not the large intestine. Similarly, iNOS-gene knockout Apc(Min/+) mice (Apc(Min/+) iNOS(-/-) or Apc(Min/+) iNOS(-/+)) developed significantly fewer adenomas in both small and large intestines than Apc(Min/+) iNOS(+/+) mice. These results suggest that iNOS-selective inhibitors could be used as a potential chemopreventive agent for colorectal cancers.

Post-initiation treatment of Indole-3-carbinol did not suppress N-methyl-N-nitrosourea induced mammary carcinogenesis in rats

The consumption of cruciferous vegetables (the Family of Cruciferae) such as cabbage, broccoli and Brussels sprouts has been shown to have cancer chemopreventive effects in humans and experimental animals. Indole-3-carbinol (I3C), one component of cruciferous vegetables, has been shown to exert cancer chemopreventive influence in liver, colon, and mammary tissue when given before or concurrent with exposure to a carcinogen. However in some reports, there has been evidence that consumption of I3C after carcinogen treatment might be associated with tumor promotion in some tissues. There have been no reports, to our knowledge, of post-initiation effects of I3C in the N-methyl-N-nitrosourea (MNU)-induced mammary tumor model in rats. Our studies were performed to examine this question. Ninety-six, 4-week-old female Sprague-Dawley rats were randomly divided into five groups. The animals of groups 1, 2 and 3 received an intraperitoneal injection of MNU at the age of 50 days. The animals of groups 4 and 5 were injected with saline only at the same time. Animals of groups 1 and 2 were given diet containing 100 ppm and 300 ppm I3C from week 1 until week 25 after MNU treatment. The animals of group 4 were given basal diet containing 300 ppm I3C without MNU treatment. All animals were killed at week 25. The incidences of mammary tumors in the groups 1, 2 and 3 were 95.8% (23/24), 83.3% (20/24) and 82.4% (28/34), respectively. The average number of tumors in the tumor bearing rats of the MNU and I3C 300 ppm group (group 2; 3.85+/-0.63) was higher than that in the MNU alone group (group 3; 2.46+/-0.31). These results represented that exposure to I3C after carcinogen treatment did not suppress development of mammary tumors.

Esters of 2-(1-hydroxyalkyl)-1,4-dihydroxy-9,10-anthraquinones with melphalan as multifunctional anticancer agents

Eight esters of 2-(1-hydroxyalkyl)-1,4-dihydroxy-9,10-anthraquinone with melphalan were prepared and tested for their antitumor activity (S-180) and cytotoxicity. 2-[1-[4-(p-Bis(2-chloroethyl)-aminophenyl)-butanoyloxy]methyl]-1,4-dihydroxy-9,10-anthraquinone and 2-[1-[4-(p-bis(2-chloroethyl)-aminophenyl)-butanoyloxy]ethyl]-1,4-dihydroxy-9,10-anthraquinone showed remarkable antitumor activity (T/C, 265 and 272%).

Chemopreventive effect of 2-(allylthio)pyrazine (2-AP) on rat colon carcinogenesis induced by azoxymethane (AOM)

An investigation was conducted to assess the chemopreventive effects of 2-(allylthio)pyrazine (2-AP), synthesized for potential use as a chemopreventive agent, after administration during the pre-initiation and post-initiation stages in a rat colon carcinogenesis model with azoxymethane (AOM). One hundred, 5-week-old, male F344 rats were randomly divided into two experiments (n = 50 each). Experiment 1 rats were randomly divided into three groups: Group 1 rats were pre-treated with 2-AP (25 or 50 mg/kg body weight, 3 consecutive days through the route of intragastric intubations) before AOM (20 mg/kg body weight, single subcutaneous (s.c.) injection) initiation. Group 2 rats were treated with AOM alone. Group 3 rats were given 2-AP alone without AOM initiation. The animals were killed at the end of each experiment (week 5) and the aberrant crypt foci (ACF) of the colonic mucosa were assessed after staining with methylene blue. Experiment 2 rats were randomly divided into three groups: Group 1 rats were given 2-AP (10, 25 or 50 mg/kg body weight, five-times intragastric intubations per week for 5 weeks from week 3) after AOM (15 mg/kg body weight, three s.c. injections) initiation for 2 weeks. Group 2 rats were treated with AOM alone. Group 3 rats were given 2-AP alone without AOM initiation. The animals were killed at the end of the experiment (week 8) and the ACF of the colonic mucosa were quantified. Total numbers of ACF/colon in Group 1 rats (pre-treated with 2-AP) tended to decrease (2-AP, 50 mg/kg body weight) or increase (2-AP, 100 mg/kg body weight) depending on the dose level. Total numbers of ACF/colon in Group 1 rats (treated with AOM followed by 2-AP, all subgroups; 160.8 +/- 38.0; 161.8 +/- 38.1; 137.1 +/- 48.4) were decreased significantly compared with the values in Group 2 rats (AOM alone; 214.8 +/- 48.1) (P < 0.05 or 0.01). The highest dose group (2-AP, 50 mg/kg body weight) had the lowest levels of total numbers of ACF/colon among the three subgroups. Total numbers of aberrant crypts (AC)/colon of the highest dose group (340.1+/- 117.9) decreased significantly compared with the value for Group 2 rats (AOM alone; 545.1 +/- 38.3). These results thus suggest that 2-AP may have potential as a chemopreventive agent against rat colon carcinogenesis after administration of AOM during the post-initiation stage.

Excision repair of adozelesin-N3 adenine adduct by 3-methyladenine-DNA glycosylases and UvrABC nuclease

Adozelesin is a synthetic analog of the antitumor antibiotic CC-1065, which alkylates the N3 of adenine in the minor groove in a sequence-selective manner. Since the cytotoxic potency of a DNA alkylating agent can be modulated by DNA excision repair system, we investigated whether nucleotide excision repair (NER) and base excision repair (BER) enzymes are able to excise the bulky DNA adduct induced by adozelesin. The UvrABC nuclease and 3-methyladenine-DNA glycosylase, that exhibit a broad spectrum of substrate specificity, were selected as typical NER and BER enzymes, respectively. The adozelesin-DNA adduct was first formed in the radiolabeled restriction DNA fragment and its excision by purified repair enzymes was monitored on a DNA sequencing gel. The treatment of the DNA adduct with a purified UvrABC nuclease and sequencing gel analysis of cleaved DNA showed that UvrABC nuclease was able to incise the adozelesin adduct. The incision site corresponded to the general nuclease incision site. Excision of this adduct by 3-methyladenine-DNA glycosylases was determined following the treatment of the DNA adduct with a homogeneous recombinant bacterial, rat and human 3-methyladenine-DNA glycosylases. Abasic sites generated by DNA glycosyalses were cleaved by the associated lyase activity of the E. coli formamidopyrimidine-DNA glycosylase (Fpg). Resolution of cleaved DNA on a sequencing gel showed that the DNA glycosylase from different sources could not release the N3-adenine adducts. A cytotoxicity assay using E. coli repair mutant strains showed that E. coli mutant strains defective in the uvrA gene were more sensitive to cell killing by adozelesin than E. coli mutant strain defective in the alkA gene or the wild type. These results suggest that the NER pathway seems to be the major excision repair system in protecting cells from the cytotoxicity of adozelesin.

A physical interaction of UvrD with nucleotide excision repair protein UvrB

The dual-incision nature of the reaction of UV-irradiated DNA catalyzed by the UvrABC complex potentially leads to excision of a damaged fragment. However, neither fragment release under nondenaturing conditions nor the UvrBC proteins are turned over. The addition of the UvrD protein to the incised DNA-UvrBC complex results in excision of the incised damaged strand and in the turnover of the UvrC protein. In an effort to better understand the involvement of UvrD in the excision step, immunoprecipitation was used to detect interacting proteins with UvrD in the DNA repair. In this communication, it is shown that UvrA and UvrB are precipitated with UvrD in solution but the UvrAB complex is not. In the incision complex, UvrB could be precipitated and the preincubation of UvrD with UvrB revealed an inhibitory effect on the turnover of the incision complex. These data imply that UvrB in the incision complex seems to recruit UvrD to the 3' incised site of the incised strand by protein-protein interaction and to allow initiation of unwinding by UvrD from the resulting nick in a 3' to 5' direction.

Effect of high or low frequency electroacupuncture on the cellular activity of catecholaminergic neurons in the brain stem

Although the opioid system plays a pivotal role in the analgesic effect of electroacupuncture (EA), it has been suggested that other peptidergic systems also may be involved in the therapeutic effect of EA. Among several peptides for EA-induced analgesia, catecholamine (CA) is associated with the descending pain inhibitory system. We evaluated whether the different frequencies of EA modified the cellular activity of central CA synthesizing neurons using double labeling immunohistochemistry between Fos-like immunoreactive (FLI) neurons and dopamine-beta-hydroxylase (DBH)/tyrosine hydroxylase (TH)-positive neurons. We observed that different frequencies of EA increased the number of FLI neurons in catecholaminergic neurons, such as the dorsal raphe (DR), hypothalamic arcuate nucleus (Arc), locus coeruleus (LC), A5 noradrenaline cells (A5), and A7 noradrenaline cells (A7). In addition, different frequencies of EA significantly increased the ratio of colocalization between FLI neurons and TH positive neurons in DR, LC and Arc. Only low frequency EA increased the neuronal activity in Arc. The ratio of double labeling between FLI and DBH positive neurons was also elevated at both LC and A5. These data demonstrate that different frequencies of EA increase the cellular activity of central CA synthesizing neurons, suggesting that the CA system plays an important role in EA-induced analgesia.

Effect of DNA topology on plasmid DNA repair in vivo

Escherichia coli nucleotide excision repair (NER) is responsible for removing bulky DNA adducts by dual incisions of the UvrABC endonuclease. Although the activity of the UvrAB complex which can induce DNA conformational change is employed in NER, the involvement of DNA topology and DNA topoisomerases remains unclear. We examined the effect of topoisomerase inhibitions on a NER in vivo system. The repair analysis of intracellular plasmid revealed that the DNA damage on positive supercoils generated by gyrase inhibition remained unrepaired, whereas the DNA damage was repaired in topoisomerase I mutants. These results suggest that DNA topology affects the NER process and the removal of positive supercoils by gyrase is vital for the efficiency of the E. coli NER system.

Conformation-dependent antibody response to Pseudomonas aeruginosa outer membrane proteins induced by immunization in humans

Outer membrane proteins (OMPs) of pathogenic bacteria have been used as protective antigens in developing bacterial vaccines. In the present study, we compared the antibody responses to a Pseudomonas aeruginosa OMP vaccine elicited in humans and rabbits by immunization. Immunization with the vaccine induced high titers of serum IgG antibody both in rabbits and humans but reactivities of the induced antibodies with the OMPs were different. The rabbit immune sera recognized most of the OMPs in the vaccine both in immunoblot and immunoprecipitation analyses. In contrast, a great variation in band pattern and intensity was observed among the human immune sera in immunoblot analysis, but not in immunoprecipitation analysis. Denaturation of the OMPs did not affect the binding activity of the rabbit immune sera as determined by ELISA, but substantially reduced those of the human immune sera and anti-OMP IgG purified from a pooled normal human plasma. These data suggest that antibody response to P. aeruginosa OMPs elicited by immunization in humans is mainly directed against discontinuous or conformation-dependent epitopes, which should be taken into account in developing vaccines, especially for OMP-derived synthetic peptides.

Effect of microstructure of low carbon steels on ultrasonic attenuation

The ultrasonic attenuation in low carbon steel with 0.04 wt% C to 0.80 wt% C was measured over a frequency range of 5 to 15 MHz, and the effects of the carbon content and normalizing temperature were analyzed. In pure iron, the attenuation is determined from the average grain size, which increases as the normalizing temperature increases; there is a noticeable effect caused by a few large grains. In the case of the hypoeutectoid steels, the proeutectoid ferrite grain, the size of which depends on prior austenite grain size, acts as the main scatterer. The prior austenite grain size increases as the carbon content decreases and the normalizing temperature increases. The colony is responsible for scattering in the eutectoid steel; scattering by pearlite is greater than that by ferrite.

Immunohistochemical localization of inducible nitric oxide synthase and 3-nitrotyrosine in rat liver tumors induced by N-nitrosodiethylamine

Human liver cancers have been associated mainly with chronic inflammations such as viral hepatitis B or C. This suggests that prolonged cell damage by chronic inflammation is critical in cancer development. Overproduction of nitric oxide (NO.) and its derivative (NOx, peroxynitrite) has been implicated as a cause of tissue damage by inflammation, thus contributing to tumor promotion. We have demonstrated the expression of the inducible isoform of nitric oxide synthase (iNOS) and 3-nitrotyrosine, a marker of peroxynitrite formation, by immunohistochemistry in preneoplastic and neoplastic rat liver tissues induced by continuous infusion of N-nitrosodiethylamine with mini-pumps. The preneoplastic lesions were characterized by proliferation of phenotypically altered hepatic foci (PAHF), dysplastic hepatocytes and oval cells. Histologically, the tumors were hepatocellular carcinomas (HCCs) of trabecular, (pseudo)glandular and solid types with or without cholangiocellular involvement. iNOS was located mainly in oval cells, capillary endothelial and muscular cells, epithelia of cholangiomas and glandular HCCs. 3-Nitrotyrosine was observed in the cytoplasms of PAHF and dysplastic hepatocytes in preneoplasias and in the cytoplasms of some living or apoptotic HCC cells, connective tissues, proteinaceous fluids, sinusoidal endothelia of tumorous hepatocytes and cholangiomas in tumors. From these observations, we suggest that: (i) chronic tissue damage by chemical carcinogens may act to induce iNOS and peroxynitrite formation; (ii) oval cells play a key role in development and/or growth of tumor tissues by producing NO. via iNOS, which may also cause tissue damage by peroxynitrite; (iii) iNOS can be considered as a phenotypic marker in cells of oval cell lineage and neovascularized capillaries in tumor tissues.

Protein carbonyl formation in blood plasma by cephalosporins

Cephalosporin antibiotics caused the formation of carbonyl groups in the plasma proteins both in vivo and in vitro. After the administration of either moxalactam (3 g/day) or cefotaxime (2 g/day) to patients for 7 days, the carbonyl contents in the plasma proteins increased markedly as determined by the 2,4-dinitrophenylhydrazine (DNPH) method. The increase in protein carbonyl groups was also visualized by the conjugation of plasma proteins with fluorescein thiosemicarbazide (FTSC) and subsequent electrophoresis. When blood plasma was incubated with cephalosporins, most of the cephalosporins tested caused the carbonyl formation in plasma proteins to significant degrees in a concentration-dependent manner. Although a number of plasma proteins and other nonplasma proteins could be modified by cephalosporins in vitro, the plasma albumin was most markedly modified in vivo as well as in vitro. The protein carbonyl formation by cephalosporins was inhibited by ascorbic acid, reduced glutathione, and cysteine, but it was not affected by FeSO4, CuSO4, desferrioxamine, EDTA, catalase, superoxide dismutase, uric acid, alpha-tocopherol, and mannitol. Sodium borohydride, when applied to moxalactam-treated plasma proteins, markedly reduced the reactivities of the protein with FTSC or DNPH, indicating that the observed reactivities of the cephalosporin-treated proteins toward FTSC or DNPH are actually due to the protein carbonyl groups. These data suggest that cephalosporins can oxidatively modify proteins in blood plasma and other tissues and that the oxidative modification of proteins may be involved in the adverse reactions observed frequently following cephalosporin therapy.

Enhancement by indole-3-carbinol of liver and thyroid gland neoplastic development in a rat medium-term multiorgan carcinogenesis model

The modification potential of indole-3-carbinol (I3C), a naturally occurring compound found in cruciferous vegetables, on neoplastic development was assessed using a rat medium-term multiorgan carcinogenesis model. One-hundred male Sprague-Dawley (SD) rats were randomly divided into three groups and sequentially treated with diethylnitrosamine (DEN; 100 mg/kg b.w., a single i.p.), N-methyl-N-nitrosourea (MNU; 20 mg/kg b.w., four times i.p., at days 5, 8, 11 and 14), and dihydroxy-di-N-propyl-nitrosamine (DHPN; 0.1% in the drinking water during weeks 1 and 3) (DMD treatment; groups 1 and 2) or the vehicles alone (group 3) in the first 3-week initiation period. Animals of groups 1 and 3 were then given diet containing 0.25% I3C from week 4 until week 24, followed by a return to basal diet for 28 weeks, and subgroups were killed at weeks 24 and 52. I3C caused significant increases in both number (no./cm2) and area (mm2/cm2) of glutathione S-transferase placental form (GST-P)-positive liver cell foci assessed at week 24 of the experiment (P<0.01, 0.001). The incidence of hepatocellular adenomas in the DMD and I3C group at week 52 showed a tendency for elevation as compared to the DMD alone group, but this was not statistically significant. The thyroid gland tumour incidences in the DMD and I3C groups were significantly increased compared with the DMD alone group values at week 52 (P<0.01). In conclusion, I3C enhanced liver and thyroid gland neoplastic development when given during the promotion stage in the present rat medium-term multiorgan carcinogenesis model.

Potential preventive effects of Chelidonium majis L. (Papaveraceae) herb extract on glandular stomach tumor development in rats treated with N-methyl-N'-nitro-N nitrosoguanidine (MNNG) and hypertonic sodium chloride

The modifying effects of Chelidonium majis L. (Papaveraceae) herb extract (CH), an analgesic traditionally prescribed for gastric and duodenal ulcer patients, on gastric tumor development were studied in rats given N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Sixty-four male 6-week-old Wistar rats were used. Group 1 rats were initially given MNNG (200 mg/kg b.w.) by gavage at days 0 and 14 as well as saturated sodium chloride solution (S-NaCl, 1 ml per rat) every 3 days during weeks 0-3 (six times), and then placed on basal diet containing 0.1 or 0.2% CH for 16 weeks from week 4. Rats of Group 2 and 3 were treated with MNNG together with S-NaCl or saline (0.9% NaCl, 1 ml per rat), respectively, timed as in Group 1 but without further treatment. All surviving animals were killed at week 20 and histopathologically investigated. In the glandular stomach, the number of preneoplastic pepsinogen 1 altered pyloric glands (PAPGs) in the MNNG + S-NaCl-->CH (0.1%) group (Group 1) was significantly smaller than in the MNNG + S-NaCl group (Group 2) (P < 0.02). The incidences of forestomach neoplastic lesions (papillomas and squamous cell carcinomas) also showed a tendency to decrease with the CH treatment. The results thus indicate that CH exerts inhibitory effects on glandular stomach carcinogenesis in the rat, so that it may have potential as a chemopreventive agent for stomach cancer in man.

The topodynamics of incision of UV-irradiated covalently closed DNA by the Escherichia coli Uvr(A)BC endonuclease

The Escherichia coli Uvr(A)BC endonuclease (Uvr(A)BC) initiates nucleotide excision repair of a large variety of DNA damages. The damage recognition and incision steps by the Uvr(A)BC is a complex process utilizing an ATP-dependent DNA helix-tracking activity associated with the UvrA2B1 complex. The latter activity leads to the generation of highly positively supercoiled DNA in the presence of E. coli topoisomerase I in vitro. Such highly positively supercoiled DNA, containing ultraviolet irradiation-induced photoproducts (uvDNA), is resistant to the incision by Uvr(A)BC, whereas the negatively supercoiled and relaxed forms of the uvDNA are effectively incised. The E. coli gyrase can contribute to the above reaction by abolishing the accumulation of highly positively supercoiled uvDNA thereby restoring Uvr(A)BC-catalyzed incision. Eukaryotic (calf thymus) topoisomerase I is able to substitute for gyrase in restoring this Uvr(A)BC-mediated incision reaction. The inability of Uvr(A)BC to incise highly positively supercoiled uvDNA results from the failure of the formation of UvrAB-dependent obligatory intermediates associated with the DNA conformational change. In contrast to Uvr(A)BC, the Micrococcus luteus UV endonuclease efficiently incises uvDNA regardless of its topological state. The in vitro topodynamic system proposed in this study may provide a simple model for studying a topological aspect of nucleotide excision repair and its interaction with other DNA topology-related processes in E. coli.