Fate of charge order in overdoped La-based cuprates

In high-temperature cuprate superconductors, stripe order refers broadly to a coupled spin and charge modulation with a commensuration of eight and four lattice units, respectively. How this stripe order evolves across optimal doping remains a controversial question. Here we present a systematic resonant inelastic x-ray scattering study of weak charge correlations in La2-xSrxCuO4 and La1.8-xEu0.2SrxCuO4. Ultra high energy resolution experiments demonstrate the importance of the separation of inelastic and elastic scattering processes. Long-range temperature-dependent stripe order is only found below optimal doping. At higher doping, short-range temperature-independent correlations are present up to the highest doping measured. This transformation is distinct from and preempts the pseudogap critical doping. We argue that the doping and temperature-independent short-range correlations originate from unresolved electron-phonon coupling that broadly peaks at the stripe ordering vector. In La2-xSrxCuO4, long-range static stripe order vanishes around optimal doping and we discuss both quantum critical and crossover scenarios.

Evidence for a Square-Square Vortex Lattice Transition in a High-T_{c} Cuprate Superconductor

Using sound velocity and attenuation measurements in high magnetic fields, we identify a new transition in the vortex lattice state of La_{2-x}Sr_{x}CuO_{4}. The transition, observed in magnetic fields exceeding 35 T and temperatures far below zero field T_{c}, is detected in the compression modulus of the vortex lattice, at a doping level of x=p=0.17. Our theoretical analysis based on Eilenberger's theory of the vortex lattice shows that the transition corresponds to the long-sought 45° rotation of the square vortex lattice, predicted to occur in d-wave superconductors near a van Hove singularity.

High-Temperature Charge-Stripe Correlations in La_{1.675}Eu_{0.2}Sr_{0.125}CuO_{4}

We use resonant inelastic x-ray scattering to investigate charge-stripe correlations in La_{1.675}Eu_{0.2}Sr_{0.125}CuO_{4}. By differentiating elastic from inelastic scattering, it is demonstrated that charge-stripe correlations precede both the structural low-temperature tetragonal phase and the transport-defined pseudogap onset. The scattering peak amplitude from charge stripes decays approximately as T^{-2} towards our detection limit. The in-plane integrated intensity, however, remains roughly temperature independent. Therefore, although the incommensurability shows a remarkably large increase at high temperature, our results are interpreted via a single scattering constituent. In fact, direct comparison to other stripe-ordered compounds (La_{1.875}Ba_{0.125}CuO_{4}, La_{1.475}Nd_{0.4}Sr_{0.125}CuO_{4}, and La_{1.875}Sr_{0.125}CuO_{4}) suggests a roughly constant integrated scattering intensity across all these compounds. Our results therefore provide a unifying picture for the charge-stripe ordering in La-based cuprates. As charge correlations in La_{1.675}Eu_{0.2}Sr_{0.125}CuO_{4} extend beyond the low-temperature tetragonal and pseudogap phase, their emergence heralds a spontaneous symmetry breaking in this compound.

Band-dependent superconducting gap in SrFe2(As0.65P0.35)2 studied by angle-resolved photoemission spectroscopy

The isovalent-substituted iron pnictide compound SrFe₂(As_1−xP_x)₂ exhibits multiple evidence for nodal superconductivity via various experimental probes, such as the penetration depth, nuclear magnetic resonance and specific heat measurements. The direct identification of the nodal superconducting (SC) gap structure is challenging, partly because the presence of nodes is not protected by symmetry but instead caused by an accidental sign change of the order parameter, and also because of the three-dimensionality of the electronic structure. We have studied the SC gaps of SrFe₂(As_0.65P_0.35)₂ in three-dimensional momentum space by synchrotron and laser-based angle-resolved photoemission spectroscopy. The three hole Fermi surfaces (FSs) at the zone center have SC gaps with different magnitudes, whereas the SC gaps of the electron FSs at the zone corner are almost isotropic and k_z-independent. As a possible nodal SC gap structure, we propose that the SC gap of the outer hole FS changes sign around the Z-X [(0, 0, 2π) − (π, π, 2π)] direction.

Strain-engineering Mott-insulating La2CuO4

The transition temperature T_c of unconventional superconductivity is often tunable. For a monolayer of FeSe, for example, the sweet spot is uniquely bound to titanium-oxide substrates. By contrast for La_2-xSr_xCuO₄ thin films, such substrates are sub-optimal and the highest T_c is instead obtained using LaSrAlO₄. An outstanding challenge is thus to understand the optimal conditions for superconductivity in thin films: which microscopic parameters drive the change in T_c and how can we tune them? Here we demonstrate, by a combination of x-ray absorption and resonant inelastic x-ray scattering spectroscopy, how the Coulomb and magnetic-exchange interaction of La₂CuO₄ thin films can be enhanced by compressive strain. Our experiments and theoretical calculations establish that the substrate producing the largest T_c under doping also generates the largest nearest neighbour hopping integral, Coulomb and magnetic-exchange interaction. We hence suggest optimising the parent Mott state as a strategy for enhancing the superconducting transition temperature in cuprates.

ARPES studies on new types of electron-doped cuprate superconductors

For more than thirty years since the discovery of superconductivity in cuprates, it has been widely agreed that the superconductivity is realized by doping a charge-transfer insulator with charge carriers through chemical substitution. For electron-doped cuprates, however, the recent development of reduction annealing methods has enabled superconductivity for a very small amount of or even without chemical substitution. In this article, we review recent angle-resolved photoemission spectroscopy studies on the new types of electron-doped cuprates with particular emphasis on the effect of reduction annealing. The presented results provide us with renewed insight into the phase diagram and the nature of the pseudogap not only on the electron-doped side but also in the entire doping range including hole doping.

Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates

We present a soft x-ray angle-resolved photoemission spectroscopy study of overdoped high-temperature superconductors. In-plane and out-of-plane components of the Fermi surface are mapped by varying the photoemission angle and the incident photon energy. No k_{z} dispersion is observed along the nodal direction, whereas a significant antinodal k_{z} dispersion is identified for La-based cuprates. Based on a tight-binding parametrization, we discuss the implications for the density of states near the van Hove singularity. Our results suggest that the large electronic specific heat found in overdoped La_{2-x}Sr_{x}CuO_{4} cannot be assigned to the van Hove singularity alone. We therefore propose quantum criticality induced by a collapsing pseudogap phase as a plausible explanation for observed enhancement of electronic specific heat.

Electronic Structure of Ce-Doped and -Undoped Nd_{2}CuO_{4} Superconducting Thin Films Studied by Hard X-Ray Photoemission and Soft X-Ray Absorption Spectroscopy

In order to realize superconductivity in cuprates with the T^{'}-type structure, not only chemical substitution (Ce doping) but also postgrowth reduction annealing is necessary. In the case of thin films, however, well-designed reduction annealing alone without Ce doping can induce superconductivity in the T^{'}-type cuprates. In order to unveil the origin of superconductivity in the Ce-undoped T^{'}-type cuprates, we have performed bulk-sensitive hard x-ray photoemission and soft x-ray absorption spectroscopy on superconducting and nonsuperconducting Nd_{2-x}Ce_{x}CuO_{4} (x=0, 0.15, and 0.19) thin films. By postgrowth annealing, core-level spectra exhibited dramatic changes, which we attributed to the enhancement of core-hole screening in the CuO_{2} plane and the shift of chemical potential along with changes in the band filling. The result suggests that the superconducting Nd_{2}CuO_{4} film is doped with electrons despite the absence of the Ce substitution.

Direct observation of orbital hybridisation in a cuprate superconductor

The minimal ingredients to explain the essential physics of layered copper-oxide (cuprates) materials remains heavily debated. Effective low-energy single-band models of the copper–oxygen orbitals are widely used because there exists no strong experimental evidence supporting multi-band structures. Here, we report angle-resolved photoelectron spectroscopy experiments on La-based cuprates that provide direct observation of a two-band structure. This electronic structure, qualitatively consistent with density functional theory, is parametrised by a two-orbital (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d_{x^2 - y^2}$$\end{document}dx2-y2 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d_{z^2}$$\end{document}dz2) tight-binding model. We quantify the orbital hybridisation which provides an explanation for the Fermi surface topology and the proximity of the van-Hove singularity to the Fermi level. Our analysis leads to a unification of electronic hopping parameters for single-layer cuprates and we conclude that hybridisation, restraining d-wave pairing, is an important optimisation element for superconductivity.

The essential physics of cuprate superconductors is often described by single-band models. Here, Matt et al. report direct observation of a two-band electronic structure in La-based cuprates.

Epidemiological Survey of Severe Fever with Thrombocytopenia Syndrome Virus in Ticks in Nagasaki, Japan

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease endemic in East Asia. Transmitted to other organisms by infected ticks, the SFTS virus (SFTSV) and is endemic to Nagasaki in western Japan. However, epidemiological information regarding SFTSV in Nagasaki ticks has not been available to date. In this study, we began by examining the sensitivities of SFTSV gene detection by real-time RT-PCR and virus isolation in cultured cells and mice. These methods could detect SFTSV in the samples containing more than 4 × 10⁰ ffu. Next, we attempted to isolate SFTSV and to detect viral gene in 2,222 nymph and adult ticks collected from May to August 2013 among seven regions of Nagasaki. However, neither virus isolation nor viral gene detection were confirmed in the tick pools. SFTSV positivity rates are considered to be very low in ticks, and viral loads are also very limited. Further investigations increasing the number of ticks and including larval samples as well as improved detection methods, may be required to find SFTSV-positive ticks in this region.

Performance of the Japanese glomerular filtration rate equation based on standardized serum cystatin C in potential kidney donors

BACKGROUND

It was reported that the glomerula filtration rate (GFR) equation based on serum creatinine underestimated the GFR in potential kidney donors. Recently, the Japanese GFR equation based on standardized serum cystatin C was reported. Therefore, we assessed the performance of the equation in potential kidney donors.

METHODS

Forty-five potential kidney donors from 2 hospitals were included. GFR was measured (mGFR) using inulin renal clearance. Serum creatinine was measured using the enzymatic method. Serum cystatin C was measured using a nephelometric immunoassay (Siemens) and calibrated to the standardized value traceable to ERM-DA471/IFCC using an equation reported previously. The estimated GFR (eGFR) was calculated using the Japanese GFR equation based on serum creatinine (eGFRcreat) and the Japanese GFR equation based on serum cystatin C (eGFRcys). Bias (mGFR - eGFR) and accuracy (P30) of the equations were evaluated.

RESULTS

Inulin clearance, eGFRcreat, and eGFRcys were 91.0 ± 18.2, 78.5 ± 18.8, and 93.3 ± 16.3 mL/min/1.73 m(2), respectively. Bias of eGFRcreat was 12.4 ± 15.8 mL/min/1.73 m(2) and significantly different from zero, indicating underestimation of GFR. Bias of eGFRcys was -2.3 ± 16.3 mL/min/1.73 m(2) and was not significantly different from zero, suggesting better performance. But, the precision (standard deviation [SD] of bias) and accuracy (P30: Percentage of participants with eGFR within 30% of mGFR) of eGFRcys were not better compared with eGFRcreat. Accuracies (P30) of eGFRcreat and eGFRcys were 87% (95% confidence interval [CI], 74-94) and 82% (95% CI, 69-91), respectively.

CONCLUSION

Bias of eGFRcys was better compared with eGFRcreat. But, the precision (SD of bias) and accuracy of eGFRcys were not superior compared with eGFRcreat in potential kidney donors.

BSL-3 Laboratory User Training Program at NUITM-KEMRI

Pathogens handled in a Biosafety Level 3 (BSL-3) containment laboratory pose significant risks to laboratory staff and the environment. It is therefore necessary to develop competency and proficiency among laboratory workers and to promote appropriate behavior and practices that enhance safety through biosafety training. Following the installation of our BSL-3 laboratory at the Center for Microbiology Research-Kenya Medical Research Institute in 2006, a biosafety training program was developed to provide training on BSL-3 safety practices and procedures. The training program was developed based on World Health Organization specifications, with adjustments to fit our research activities and biosafety needs. The program is composed of three phases, namely initial assessment, a training phase including theory and a practicum, and a final assessment. This article reports the content of our training program.

Bilateralstruktur der Wolle

Die von der Bilateralstruktur herrührende teilweise Färbung der Wollhaare ist nicht nur auf die speziellen Farbstoffe beschränkt, sondern läßt sich auf alle wichtigen Farbstoffklassen erweitern, wenn der pH-Wert des Bades nicht stark von 7 abweicht und die Farbstoffkonzentration nicht zu groß ist.

Die scheinbaren isoelektrischen Punkte der beiden Teile des Cortex, die in den färberischen Eigenschaften voneinander verschieden sind, wurden histochemisch bestimmt. Es wurde vorgeschlagen, den auf der Innenseite der Krümmung liegenden acidophilen Teil (sog. Para-Cortex) „A-Cortex" und den auf der Außenseite liegenden basophilen Teil (sog. Ortho-Cortex) „B-Cortex" zu nennen.

A- und B-Cortex zeigen die voneinander unterschiedenen UV- Absorptionen: bei 3130 A weist der A-Cortex größere Absorption als der B-Cortex auf, während das Verhältnis bei 2800 und 2650 A gerade umgekehrt ist.

Von etwa einem Drittel der unter der Haut befindlichen Länge ab nach der Spitze hin besitzt das Haar eine Bilateralstruktur wie die des Haarteils außerhalb der Haut, während der unmittelbar über der Tiefe der Wurzel stehende Teil gleichmäßig die färberische Eigenschaft wie der B-Cortex aufweist.

Dynamic Measurements on Polymer Liquid Crystals**

The dynamic experiments were made on the solutions of poly (l,4-phenylene-2,6-benzobisthioazole) (PBT) in poly(phosphoric acid) at frequencies from 10−2 to 102 radian· sec−1. For the liquid-crystalline solutions, the logarithmic plots of G′ and G″ against frequency show abnormally small slopes and those of η′ exhibit large slopes at low frequencies in contrast to the plots for the optically isotropic solutions. However, the viscoelastic behavior of liquid-crystalline solutions is regarded as linear. The temperature of anisotropic-isotropic phase transition of solution is higher for high-molecular-weight PBT than for lowmolecular-weight PBT. The dilution of solution lowers the transition temperature. The transition goes through various stages of mixed phases. The method of reduced variables is applicable to the isotropic solutions, and the resulted composite curves were discussed. The method, however, is inapplicable to the anisotropic solutions, suggesting that the configuration, interaction and aggregation state of molecules in liquid-crystalline solutions may change sensitively by temperature. The slow relaxation mechanisms are involved in the mesophase systems, but the quick shrinkage of highly oriented nematic mesophase at the onset of relaxation produces the zigzag-fibrillar structure of fibers and films made by stretch spinning or casting.

The NUITM-KEMRI P3 Laboratory in Kenya: Establishment, Features, Operation and Maintenance

A biocontainment facility is a core component in any research setting due to the services it renders towards comprehensive biosafety observance. The NUITM-KEMRI P3 facility was set up in 2007 and has been actively in use since 2010 by researchers from this and other institutions. A number of hazardous agents have been handled in the laboratory among them MDR-TB and yellow fever viruses. The laboratory has the general physical and operational features of a P3 laboratory in addition to a number of unique features, among them the water-air filtration system, the eco-mode operation feature and automation of the pressure system that make the facility more efficient. It is equipped with biosafety and emergency response equipments alongside common laboratory equipments, maintained regularly using daily, monthly and yearly routines. Security and safety is strictly observed within the facility, enhanced by restricted entry, strict documentation and use of safety symbols. Training is also engrained within the operation of the laboratory and is undertaken and evaluated annually. Though the laboratory is in the process of obtaining accreditation, it is fully certified courtesy of the manufactures’ and constructed within specified standards.

Sleeping arrangement and house structure affect bed net use in villages along Lake Victoria

Background

Although insecticide-treated bed nets are effective tools, use often does not follow ownership. House structure and space arrangements may make the attempt to use bed nets difficult, especially for school age children. The objectives of this study were to explore whether an individual's sleeping arrangements and house structure affect bed net use in villages along Lake Victoria in western Kenya.

Methods

Sleeping arrangements of residents were directly observed for use of a bed net, use of a bed, and location. House size, number and types of rooms, bed availability, and residents' ages were estimated. The family heads and mothers were asked about the reason for not using bed nets. Individual bed net use was examined against age and sleeping arrangement. Net use at the household level was examined against four variables: bed availability, bed net availability, house size, and number of rooms.

Results

Bed net use by children between five and 15 years of age was lower than that among the other age classes. However, age was dropped from the final model, and sleeping arrangement was significantly associated with net use. Net use was significantly associated with bed availability, number of rooms and their interaction.

Conclusion

Net use was affected by sleeping arrangement and availability of suitable locations for hanging nets, in addition to net availability. Most residents had likely not realized that sleeping arrangement was a factor in net use. The ease of hanging a net is particularly important for children.

Evaluation of energy recovery and CO2 reduction potential in Japan through integrated waste and utility management

This paper examines the potential of integrated waste and utility power management over the mid-term planning horizon in Japan. Energy recovery and CO(2) emission reduction were estimated under two situations: (1) energy recovery efforts within the current waste management/power generation framework and (2) integrated waste management with sewage treatment systems and electric power industries. Scenario simulation results showed that under the current policy framework it is not feasible to achieve large energy recovery and CO(2) emission reduction, while the integrated waste management scenarios show the potential of large energy recovery which is equivalent to about an 18 million t-CO(2) emission reduction. The utilization of dry wastes for power generation at existing fossil power stations is significant in achieving the result. We also consider the effects of the 'CO(2) emission per GW generated' for electric power generation on the total CO(2) emission reduction because it varies by country and assumptions selected. Although this research did not include an economic analysis, based on estimated CO(2) emissions and energy recovery, the integrated scenarios indicate a large potential in countries that have high dependence of fossil power generation and relatively low power generation efficiency.

[Extensive educational program for high performance medical technologists]

The education system for medical technologists has recently been revolutionized, their educational periods vary from 2 to 9 years, and some already have doctoral degrees. In such a new situation, our faculty thinks that the most important point for new medical technologists is the ability to have a broad view of the clinical fields, especially the view of patients. Special training in bed-side education and a stint in several divisions, such as the surgical operation room, rehabilitation. radiological examination room, pharmacy, central storage room of medical records, and medical informatics, and so on, of the hospital is a powerful tool to obtain a broad view of the various clinical fields and can be essential for developing high performance medical technologists. As nine years have passed since starting this education, we evaluated this practice through systematic personal communication. As a result, it was found to be extremely effective for many reasons such as having a continuous image of the patient when they examine the blood sample in the hospital laboratory, showing advanced laboratory performance, and having no mental barrier to visiting the wards and so on. The abilities of our alumni are praised highly by many large scale hospitals around the country and 50% of them are working in the clinical laboratory division of these hospitals. About 40% are working in the division of research and development in various companies. We express sincere thanks to the director and all cooperative individuals for this course in the Osaka University Hospital.

Genotypic variation among lineages of Trypanosoma cruzi and its geographic aspects

Isozyme analysis with 18 enzyme loci was conducted on 146 isolates of Trypanosoma cruzi from Mexico, Guatemala, Colombia, Ecuador, Peru, Brazil, Bolivia, Paraguay and Chile. Forty-four different MLGs (groups of isolates with identical multilocus genotypes) were identified and a phylogeny was constructed. The phylogenetic tree consisted of two main groups (T. cruzi I, T. cruzi II), and the latter was further divided into two subgroups (T. cruzi IIa, T. cruzi IIb-e). Evidence of hybridization between different MLGs of T. cruzi II was found, which means that genetic exchanges seem to have occurred in South American T. cruzi. On the other hand, the persistence of characteristic T. cruzi I and T. cruzi II isozyme patterns in single small villages in Bolivia and Guatemala suggested that genetic exchange is very rare between major lineages. A significant difference in genetic diversity was shown between T. cruzi I and T. cruzi II from several indices of population genetics. Two possibilities could explain this genetic variation in the population: differences in evolutionary history and/or different tendencies to exchange genetic material. Broad-scale geographic distributions of T. cruzi I and T. cruzi IIb-e were different; T. cruzi I occurred in Central America and south to Bolivia and Brazil, while T. cruzi IIb-e occurred in the central and southern areas of South America, overlapping with T. cruzi I in Brazil and Bolivia.

Dioxin and fly ash free incineration by ash pelletization and reburning

Dioxins (DXNs) in municipal waste incinerator fly ash were effectively reduced by pelletizing the mixture of ash, cement, and sodium phosphate and reburning the pellets in a laboratory scale bubbling fluidized bed (BFB) furnace. Three types of pellets--A, B and C, of various sizes and compositions were used in the experiments. The efficiency of DXN reduction in the pellet matrix was proportional to the incineration time, temperature, and degree of pellet incineration. At 700 degrees C and incineration time sufficient for a complete burnout, the efficiency of DXN reduction in the pellets of type A and C was found to be 99.9% and 99.7%, respectively. Correspondingly, the DXN concentration in the pellets decreased from 862 ng TEQ/kg to 0.9 ng TEQ/kg for pellets A and 2.2 ng TEQ/kg for pellets C. The residual concentration of coplanar polychlorinated biphenyls (coplanar PCBs) was below 0.2 ng TEQ/kg and 0.4 ng TEQ/kg, respectively. Assuming a tortuosity factor of tau = 3 and the reaction rate constants of 0.013 m/s (at 700 degrees C) and 0.025 m/s (at 800 degrees C), the experimental pellet incineration times were reasonably predicted by using the shrinking core model. Possible DXN evaporation from the pellets was also studied. The amount of DXNs in the flue gas captured by an impinger trap was less than 3% when the reactor was operated at 700 and 800 degrees C. The described method of fly ash pelletization and reburning seems to be a relatively easy and inexpensive way to reduce both the emission of DXNs and the amount of fly ash.

[Making a low cost IPSec router on Linux and the assessment for practical use]

We installed Linux and FreeS/WAN on a PC/AT compatible machine to make an IPSec router. We measured the time of ping/ftp, only in the university, between the university and the external network. Between the university and the external network (the Internet), there were no differences. Therefore, we concluded that CPU load was not remarkable at low speed networks, because packets exchanged via the Internet are small, or compressions of VPN are more effective than encoding and decoding. On the other hand, in the university, the IPSec router performed down about 20-30% compared with normal IP communication, but this is not a serious problem for practical use. Recently, VPN machines are becoming cheaper, but they do not function sufficiently to create a fundamental VPN environment. Therefore, if one wants a fundamental VPN environment at a low cost, we believe you should select a VPN router on Linux.

Risk of Toxoplasma gondii infection in slaughterhouse workers in Kitakyushu City

To clarify the risk of Toxoplasma gondii infection among slaughterhouse workers, we investigated Toxoplasma antibody in workers and swine in the meat center of Kitakyushu City and discussed the result from the standpoint of working conditions. Among 67 slaughterhouse workers, 22 were positive for Toxoplasma antibody (positive rate, 32.8%), while among 208 swine, 19 were positive (positive rate, 9.1%). When classified by ages of workers, positive rates in workers were 0% at the age of 30 or less and around 40% at the age of 31 and over. Especially, positive rate became as high as 66.7% in workers aged 61 and over. Positive rates for Toxoplasma antibody in workers classified by duration of employment were 25% for 5 years or less and 41.5% for 6 years and over. Moreover, there was no difference in positive rates of Toxoplasma antibody between swine slaughterers (positive rate, 32.4%) and cattle slaughterers (33.9%). Although overall positive rate of Toxoplasma antibody in slaughterers was higher, positive antibody in younger slaughterers or that of shorter duration of employment was considerably low. In addition, since positive rate of Toxoplasma antibody in swine brought to the slaughterhouse has decreased remarkably in comparison to the previous study, risk of toxoplasmosis in slaughterhouse workers also seemed to have decreased.

Fluvastatin suppresses oxidative stress and fibrosis in the interstitium of mouse kidneys with unilateral ureteral obstruction

BACKGROUND

Recently, we demonstrated increased oxidative stress in the interstitium of ureteral obstructed kidneys based on the increased expression of heme oxygenase-1 and immunohistochemical detection of advanced glycation end products (AGE) in the interstitium. Antioxidant therapy may have a therapeutic potential toward interstitial fibrosis of unilateral ureteral obstruction (UUO) kidneys. Fluvastatin is an HMG-CoA reductase inhibitor and has been demonstrated to have an antioxidant activity in vitro.

METHODS

The effects of fluvastatin on UUO kidneys from the viewpoints of antioxidant action in vivo and antifibrosis action were studied. To investigate the antioxidant action and its therapeutic efficacy of fluvastatin in UUO kidneys, AGE accumulation and fibrosis in the obstructed kidneys was compared among vehicle-, pravastatin-, or fluvastatin-treated (10 or 40 mg/kg/day) groups.

RESULTS

Tubulointerstitial fibrosis was significantly attenuated in fluvastatin-treated animals. Fluvastatin significantly suppressed the degree of immunostaining of AGE in UUO kidneys.

CONCLUSIONS

These results provide evidence for the antioxidant action of fluvastatin in vivo. The decreased interstitial fibrosis along with a decreased oxidative stress marker in the interstitial lesion strongly suggests the existence of a causal relationship between them. Fluvastatin may have therapeutic value in slowing or preventing interstitial fibrosis in progressive renal disease.

Detection of kinetoplast DNA of Trypanosoma cruzi from dried feces of triatomine bugs by PCR

It is important to clarify the distribution of infected triatomine bugs in the endemic area of Chagas' disease for proper control. In the present study, we tried to detect T. cruzi kinetoplast DNA by PCR from dried triatomine feces collected from the house wall of an endemic area to assess the distribution of infected bugs more easily. The primers (P35/P36) were chosen to amplify the conserved region within the minirepeats of T. cruzi kinetoplast minicircle DNA. The kinetoplast DNA of T. cruzi could be actually detected in the dried feces collected from the wall of a brick-built house in Santa Cruz, Bolivia. Next, we examined the stability of T. cruzi kinetoplast DNA in the feces exposed to artificial environments. T. cruzi DNA was also detected by PCR in the feces left for 26 weeks at 25 degrees C and in those left for 4 weeks at 40 degrees C. The present study indicates that examination of dried feces on the wall can be an effective tool for surveillance of the natural infection of triatomine bugs that live in houses.

Fluvastatin suppresses oxidative stress and fibrosis in the interstitium of mouse kidneys with unilateral ureteral obstruction

BACKGROUND

Recently, we demonstrated increased oxidative stress in the interstitium of ureteral obstructed kidneys based on the increased expression of heme oxygenase-1 and immunohistochemical detection of advanced glycation end products (AGE) in the interstitium. Antioxidant therapy may have a therapeutic potential toward interstitial fibrosis of unilateral ureteral obstruction (UUO) kidneys. Fluvastatin is an HMG-CoA reductase inhibitor and has been demonstrated to have an antioxidant activity in vitro.

METHODS

The effects of fluvastatin on UUO kidneys from the viewpoints of antioxidant action in vivo and antifibrosis action were studied. To investigate the antioxidant action and its therapeutic efficacy of fluvastatin in UUO kidneys, AGE accumulation and fibrosis in the obstructed kidneys was compared among vehicle-, pravastatin-, or fluvastatin-treated (10 or 40 mg/kg/day) groups.

RESULTS

Tubulointerstitial fibrosis was significantly attenuated in fluvastatin-treated animals. Fluvastatin significantly suppressed the degree of immunostaining of AGE in UUO kidneys.

CONCLUSIONS

These results provide evidence for the antioxidant action of fluvastatin in vivo. The decreased interstitial fibrosis along with a decreased oxidative stress marker in the interstitial lesion strongly suggests the existence of a causal relationship between them. Fluvastatin may have therapeutic value in slowing or preventing interstitial fibrosis in progressive renal disease.

Apoptosis induced by hypertonicity in Madin Darley canine kidney cells: protective effect of betaine

BACKGROUND

In mammals, the renal medulla is in a hypertonic environment related to the renal concentrating mechanism. Renal cells accumulate osmolytes such as betaine to protect cells from the perturbing effect of high concentration of electrolytes. Hypertonicity-induced cell death and the effect of betaine were investigated in Madin Darby canine kidney (MDCK) cells.

METHODS

Cell viability was detected by 3-(4,5-dimethylthiazo-2-yl)-2,5-diphenyl tetrazolium bromide assay. DNA fragmentation was determined by FACS analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) staining and agarose gel electrophoresis. Activities of caspase-1, -3, -8, and -9 were measured.

RESULT

When the cells were exposed to 700 mOsm medium for 24 h, 40% of the cells were detached. TUNEL staining showed that about 20% of detached cells were apoptotic, indicating that both necrosis and apoptosis contributed to the hypertonicity-induced cell death in MDCK cells. DNA laddering was demonstrated in hypertonic cells. Caspase-3, -8, and -9 activities of the adherent cells exposed to 700 mOsm for 24 h increased approximately 20-, 3-, and 4-fold the value of isotonic cells, respectively. However, there was no significant change in caspase-1 activity. Addition of 1 mM betaine into the medium protected the cells against the hypertonicity-induced cytotoxicity and apoptosis. Betaine prevented the induction of caspase-3, -8, and -9 activities after hypertonic exposure to about 50%.

CONCLUSIONS

The present study demonstrates that (i) apoptosis is involved in the hypertonicity-induced cell death in MDCK cells; (ii) caspase-3, -8, and -9 may contribute to the apoptosis; and (iii) betaine has protective effect on the hypertonicity-induced apoptosis.

Evaluation of waste pyrolysis characteristics in a pressurized fluidized bed reactor

To obtain the distribution of fuel components to gas, tar and char in a pressurized fluidized bed waste pyrolyzer, experiments were conducted with a laboratory scale fluidized bed reactor. Waste samples were fed batchwise from the top of the reactor into the fluidized bed of silica sand and pyrolyzed by nitrogen/nitrogen-O2 gas and the effects of pressure, particle size, heating rate and oxygen addition were investigated. In the case of rubber, the char yield tended to increase a little and the tar yield decrease over the pressure of 304-709 kPa. In comparison with the thermogravimetry data it was clearly demonstrated that the char yield from fluidized bed pyrolysis is much lower. A small amount of oxygen addition decreased both tar and char yields but its further increase did not affect them very much.

Effect of FK 506 in the treatment of autoimmune glomerulonephritis in Brown Norway rats

Mercuric chloride (HgCl2) induces a lymphoproliferative disorder and autoimmune glomerulonephritis in Brown Norway (BN) rats. The effects of a new immunosuppressant, FK 506, on this model of glomerulonephritis were studied. BN rats were treated with HgCl2 according to a standard protocol (HgCl2 1 mg/kg s.c. 3 times/week). FK 506 was inoculated subcutaneously daily from day 15 to day 28. Animals were divided into 4 groups: group 1, rats were treated with normal saline alone and sacrificed on day 28; group 2, rats were treated with HgCl2 alone and sacrificed on day 14; group 3, rats were treated with HgCl2 alone and sacrificed on day 28, and group 4, rats were treated with HgCl2 and FK 506 (from day 15 to day 28) and sacrificed on day 28. Rats developed proteinuria by day 7, which reached a plateau level by day 14. On day 14, renal histology showed prominent mesangial cellular proliferation and the expansion of mesangial matrix. Electron microscopic study showed the effacement of visceral epithelial foot processes and the microvillous transformation of the visceral epithelium. Immunofluorescence study showed strong linear staining for IgG and the adhesion molecule ICAM-1 in all glomeruli. Treatment with FK 506 (1 mg/kg s.c. daily) resulted in a remarkable reduction in proteinuria on day 28 (493.5 +/- 48.3 vs. 24.4 +/- 13.5 mg/day) and an improvement in the morphological lesions. These findings suggest that FK 506 could be useful in the treatment of some human glomerulonephritides.

Calcium channel blockers inhibit proliferation and matrix production in rat mesangial cells: possible mechanism of suppression of AP-1 and CREB activities

BACKGROUND

Calcium channel blockers (CCBs) are reported to attenuate the loss of renal function in various glomerulonephritides.

METHODS

To determine the mechanism of action of these drugs, we investigated the effects of CCBs on cell proliferation and extracellular matrix (ECM) production in cultured rat mesangial cells.

RESULTS

While stimulation with 5% fetal calf serum (FCS) increased [(3)H]thymidine and [(3)H]proline incorporation into quiescent mesangial cells, incubation with nifedipine and cilnidipine inhibited the increase in a dose-dependent manner. Northern blot analysis demonstrated that 5% FCS increased the expression of transforming growth factor beta (TGF-beta) and fibronectin (FN) mRNA and that CCBs significantly reduced this induction, indicating that CCBs may reduce ECM production through inhibiting TGF-beta and FN. Since activator protein 1 (AP-1) regulates cell proliferation and TGF-beta expression, we evaluated the AP-1 activity by gel mobility shift analysis. Nuclear extracts of FCS-treated cells showed a strong binding to AP-1-specific oligonucleotides which was suppressed by CCBs, suggesting that these agents may inhibit cell proliferation by suppressing AP-1. CCBs also inhibited the binding activity of cyclic adenosine monophosphate responsive element binding protein which regulates FN gene expression. However, neither CCBs nor FCS affected the NFkappaB activity.

CONCLUSION

These results suggest that CCBs may, in part, inhibit the progression of glomerulonephritis through non-hemodynamic actions that include the suppression of mesangial cell proliferation and the production of ECM.

Probucol suppresses ICAM-1 expression in rat mesangial cells: possible role of IL-1

Interleukin-1 (IL-1) participates in the progression of glomerulonephritis by up-regulating intercellular adhesion molecule-1 (ICAM-1) expression in experimental glomerulonephritis. Probucol, an anti-hyperlipidemic agent, ameliorates some types of glomerulonephritis regardless of serum cholesterol levels, and is also reported to inhibit IL-1 release from macrophages in atherosclerotic lesions. However, little is known about the mechanism of this favorable action on glomerular injury. We examined whether or not probucol inhibits ICAM-1 expression by suppression of IL-1 action in cultured rat mesangial cells. In this brief report, we review the actions of probucol on IL-1 secretion and discuss the possible mechanism by which probucol may suppress the glomerular injury.

Enhanced interstitial expression of caldesmon in IgA nephropathy and its suppression by glucocorticoid-heparin therapy

BACKGROUND

With progressive renal disease, structural derangement increasingly encompasses the tubulointerstitial compartment. Tubulointerstitial injury is a critical determinant of renal functional reserve and prognosis in renal disease. Interstitial cells acquiring characteristic of myofibroblasts are an important contributor to interstitial fibrosis. Caldesmon, a calmodulin or actin binding protein, is a molecular marker of differentiation in smooth muscle cells and has recently been shown by us to be a good marker of mesangial cell activation in IgA nephropathy patients. METHODS. We studied whether the expression of caldesmon in interstitium of the kidney was enhanced in the process of glomerular disease and whether it would be a marker of interstitial activation in specific disease states. We performed immunohistochemical staining with anti-caldesmon antibodies in 38 biopsy specimens from IgA nephropathy patients and analysed them quantitatively with a computer-aided manipulator. Interstitial caldesmon expression were compared with histological changes and clinical parameters.

RESULTS

Caldesmon expression was enhanced where interstitial cell infiltration and fibrosis were found. Immunoelectron microscopy revealed that caldesmon staining in the renal interstitium was cytoplasmic, and in the processes of myofibroblast-like cells. Caldesmon expression was more prominent in the intense CD68 infiltrated group than in the low positive cells infiltrated group. Patients showing high intensity of interstitial caldesmon expression had significantly higher urinary protein excretion than those showing low intensity of caldesmon expression. Next, 15 patients were treated with glucocorticoid and heparin for 4-8 weeks and re-biopsies were performed. Caldesmon expression was reduced in concomitant with decreased interstitial cell infiltration. Follow-up of these patients (average 24 months) revealed a significant suppression of urinary protein excretion and significant improvement of creatinine clearance.

CONCLUSION

These results suggest that the interstitial caldesmon expression is associated with the progression of IgA nephropathy, and glucocorticoid--heparin therapy may reverse the phenotypic change of interstitial cells during the disease process of glomerulonephritis.

High water intake ameliorates tubulointerstitial injury in rats with subtotal nephrectomy: possible role of TGF-beta

BACKGROUND

It has been shown that tubulointerstitial injury correlates well with a decline of renal function. In this study, we investigated the effect of high water intake (HWI) on functional and structural parameters in rats with subtotal nephrectomy.

METHODS

Two weeks after the ablative procedure, rats were divided into two groups. One group received the treatment with HWI (3% sucrose added to drinking water) for eight weeks. Functional parameters were compared with sham-operated control (CONT) or nephrectomized rats without treatment (NX). Remnant kidneys were then assessed histologically for evidence of interstitial fibrosis and glomerulosclerosis.

RESULTS

Creatinine clearance was significantly improved in HWI rats compared with NX rats. Simultaneously, urinary protein was also significantly reduced in HWI rats. HWI predominantly ameliorated interstitial lesions and, to a lesser extent, glomerular lesions. Northern blot analysis demonstrated that transforming growth factor-beta (TGF-beta) mRNA expression was significantly suppressed in HWI rats. In situ hybridization revealed that HWI suppressed TGF-beta mRNA expression mainly in the outer medulla. Fibronectin mRNA was also reduced by the HWI treatment. The changes in TGF-beta and fibronectin mRNA were in parallel with Na+/myo-inositol cotransporter (SMIT) mRNA, which is regulated by extracellular osmolarity. Immunohistochemistry demonstrated that protein expression of TGF-beta and fibronectin coincided with the mRNA expression.

CONCLUSION

These results suggest that HWI reduces TGF-beta mRNA expression in medullary interstitium and ameliorates tubulointerstitial injury in rats with reduced renal mass.

Response to hypertonicity in mesothelial cells: role of Na+/myo-inositol co-transporter

BACKGROUND

During peritoneal dialysis, the peritoneal mesothelium is exposed continually to hypertonic dialysates. The purpose of this study is to see if rat mesothelial cells have an osmoregulatory mechanism to adapt to hypertonic environment.

METHODS

The intracellular content of organic osmolytes was measured by HPLC methods. Myo-inositol transport activity was measured by Na+-dependent uptake of [3H]myo-inositol. mRNA abundance for the Na+/myo-inositol co-transporter (SMIT) was examined by Northern and slot-blot analyses.

RESULTS

In isotonic mesothelial cells, only myo-inositol could be detected. After switching to hypertonic medium made by addition of NaCl, myo-inositol content gradually increased and peaked at 48 h after the switch. The myo-inositol content in hypertonic cells increased > 7-fold over the value in isotonic cells. The contents of betaine and glycerophosphorylcholine (GPC) also increased but were less than that of myo-inositol. Sorbitol was not accumulated in this condition. When glucose was used to increase medium osmolality, all of the four osmolytes were increased by hypertonicity (myo-inositol > sorbitol > GPC > betaine). Thus, myo-inositol is the most abundant osmolyte in the mesothelial cells. Na+-dependent myo-inositol uptake in hypertonic cells was approximately 7-fold the uptake in isotonic cells, reaching a maximum 16 h after switching to a hypertonic medium. The uptake rate increased as medium osmolality increased from 300 to 500 mosm/kg. SMIT mRNA rapidly increased after increasing medium osmolality, reaching a maximum 8 h after the switch. The relative increase in the mRNA abundance was approximately 11 times isotonic levels.

CONCLUSIONS

Mesothelial cells respond to extracellular hypertonicity by increasing SMIT mRNA abundance, myo-inositol transport activity and accumulating myo-inositol into the cells.

Effect of hypertonic stress on amino acid levels and system A activity in rat peritoneal mesothelial cells

OBJECTIVE

Peritoneal mesothelial cells (PMC) are exposed to a hypertonic environment during peritoneal dialysis. When exposed to a hypertonic medium, many types of cells accumulate small osmotically active organic solutes, which are called osmolytes, to match the higher external osmolality. However, no information has been available concerning the osmolytes in PMC. To investigate osmoregulation in rat PMC, the levels of amino acids in the cells and the activity of system A, a major neutral amino acid transport, were measured after switching to a medium made hypertonic by the addition of NaCl. System A was measured by Na+-dependent [14C]-2-methylamino-isobutyric acid (MeAIB) uptake.

RESULTS

Total amount of 20 amino acids increased from 306 to 757 nmol/mg protein after 12 hours of hypertonicity. The amount of neutral amino acids accounted for 81% of the increase in total amino acids. Glutamine, alanine, glycine, threonine, and serine were the major neutral amino acids that accumulated in the hypertonic mesothelial cells. The amount of neutral amino acids increased 2.9-fold after 12 hr of hypertonicity, and decreased thereafter. MeAIB uptake increased 36-fold relative to the uptake in isotonic cells after 4-8 hr of hypertonicity. When the culture medium was made hypertonic by adding raffinose or glucose, the activity of system A was also stimulated (raffinose > glucose > NaCl). System A was located on both the apical and basal sides of isotonic PMC, and extracellular hypertonicity stimulated the MeAIB uptake on both sides.

CONCLUSIONS

These data indicate that neutral amino acids and system A transport play an important role in early-phase osmoregulation in rat peritoneal mesothelial cells.

Effect of a novel immunosuppressant, FK 506, on autoimmune glomerulonephritis in Brown Norway rats

Mercuric-chloride (HgCl2) induces a lymphoproliferative disorder and autoimmune glomerulonephritis in Brown Norway rats. The effects of a new immunosuppressant FK 506 on this model of glomerulonephritis were studied. Brown Norway rats were treated with HgCl2 according to a standard protocol (HgCl2 1 mg/kg s.c. 3 times/ week). Rats developed proteinuria at day 7, which reached a plateau level at day 14. On day 14, renal histology showed prominent mesangial cellular proliferation and the expansion of mesangial matrix. Electron microscopic study showed the effacement of visceral epithelial foot processes and the microvillous transformation of the visceral epithelium. Immunofluorescence study showed a strong linear staining for IgG and the adhesion molecule ICAM-1 in all glomeruli. Coadministration of FK 506 (1 mg/kg s.c. daily) prevented the appearance of proteinuria at day 14 (621.4 +/- 30.5 vs. 2.2 +/- 2.7 mg/day) and the morphological lesions. These findings suggest that FK 506 could be useful for the therapy of certain types of human glomerulonephritis.

[Bilateral homonymous hemianopsia with atrial fibrillation]

We encountered an 80-year-old man with sudden bilateral visual disturbance. When he was admitted to the hospital, his blood pressure was 138/70 mmHg, and an ECG revealed atrial fibrillation. Neurological examination showed only bilateral homonymous hemianopsia with no nystagmus or impairment of eye movement. He did not have paralysis cerebellar ataxia, or speech disturbance. Therefore, there was no evidence of obstruction of the thalamogeniculate or thalamoperforating artery. Magnetic resonance imaging of the brain showed cerebral infarctions in both occipital lobes. Perimetry showed bilateral homonymous hemianopsia; the left side of the macula was spared. The lack of neurological deficit other than bilateral homonymous hemianopsia indicates that only the right and left cortical branches of the posterior cerebral artery were occluded.

Up-regulation of HSP47 in the mouse kidneys with unilateral ureteral obstruction

BACKGROUND

Unilateral ureteral obstruction (UUO) is a well established experimental model of renal injury leading to interstitial fibrosis. The molecular and cellular mechanism(s) of interstitial fibrosis in UUO are beginning to be elucidated. In the progression of interstitial fibrosis in UUO, up-regulation of collagen synthesis is commonly observed. HSP47 is a collagen-binding stress protein and is thought to be a collagen-specific molecular chaperone, which plays a pivotal role during the biosynthesis and secretion of collagen molecules in the endoplasmic reticulum. The synthesis of HSP47 has been demonstrated to always parallel that of collagen in physiological and pathophysiological conditions. It is well recognized that renin-angiotensin system (RAS) is enhanced in the setting of UUO and that enhanced RAS has been implicated in the pathogenesis of interstitial fibrosis in the obstructed kidneys.

METHODS

To investigate the role of HSP47 in the progression of interstitial fibrosis in mouse UUO, the expression of HSP47 was examined by Northern blotting, immunohistochemistry and in situ hybridization in the obstructed kidneys. To test the possible involvement of enhanced RAS on the HSP47 expression, we examined the effects of lisinopril, an angiotensin converting enzyme inhibitor, on interstitial fibrosis. HSP47 and type I collagen mRNA expression.

RESULTS

By Northern blot analysis, HSP47 mRNA was significantly up-regulated at 12 hours (about twice that of sham operated kidneys) after the onset of ureteral obstruction, further increased and stayed at the increased level until seven days (about 8 times that of sham operated kidneys). HSP47 mRNA and protein expression were observed in the periglomerular and peritubular interstitial regions of the obstructed kidneys. Distribution of smooth muscle alpha actin and type I collagen immunoreactivity were similar to the HSP47 distribution pattern, suggesting that HSP47 was up-regulated in the myofibroblasts. Lisinopril ameliorated the expansion of cortical interstitium in the obstructed kidneys at four and seven days after ureteral obstruction. HSP47 mRNA expression was suppressed at four and seven days, whereas type I collagen mRNA was suppressed only at seven days after the onset of ureteral obstruction.

CONCLUSIONS

These results demonstrate the early and persistent up-regulation of HSP47 during the progression of interstitial fibrosis in mouse UUO kidneys, and further suggest the potential role of HSP47 in the pathogenesis of interstitial fibrosis in the obstructed kidneys. Partial suppression of HSP47 mRNA expression by lisinopril at day 4 and day 7 after ureteral obstruction suggests that there are other immediate trigger(s) that induce the HSP47 mRNA expression. Identification of the molecular mechanism of HSP47 induction during UUO may give an insight into the novel aspects of the molecular pathophysiology of interstitial fibrosis in obstructive nephropathy.

Effects of hypertonic stress on transforming growth factor-beta activity in normal rat kidney cells

Hypertonicity is known to modulate the expression of some genes and the action of several cytokines. We evaluated whether hypertonicity would increase the expression and/or activity of transforming growth factor-beta (TGF-beta) in normal rat kidney (NRK) cells. The bioassay for TGF-beta showed that mature TGF-beta activity was significantly increased when the cells were cultured in a hypertonic medium (500 mOsm/kg). Comparing to the isotonic medium, hypertonicity accelerated the increase in TGF-beta activity during the initial 24 hours after changing the medium. The activity was increased as the medium osmolality increased from 300 to 500 mOsm/kg. Raffinose was found to be the most effective in increasing TGF-beta activity. NaCl, glucose, and mannitol also increased TGF-beta activity. In contrast, total TGF-beta (mature and latent) activity and TGF-beta mRNA abundance did not change significantly, suggesting that hypertonicity activated TGF-beta without affecting the synthesis of TGF-beta. To determine whether collagen synthesis was increased by hypertonicity, we examined [3H] proline incorporation into NRK cells cultured in hypertonic medium. Proline incorporation increased in an osmolality-dependent manner. Raffinose was also the most effective solute at increasing the proline incorporation. Furthermore, anti-TGF-beta antibody prevented the increase in proline incorporation induced by hypertonicity. These results suggest that hypertonicity promotes the processing of latent TGF-beta to the biologically active form, resulting in the stimulation of collagen synthesis in NRK cells.