Near-threshold Lambda(1520) production by the gamma(p)-->K{+}Lambda(1520) reaction at forward K+ angles

Differential cross sections and photon-beam asymmetries for the gamma(p)-->K{+}Lambda(1520) reaction have been measured with linearly polarized photon beams at energies from the threshold to 2.4 GeV at 0.6<cos(theta){c.m.}{K}<1. A new bump structure was found at W approximately 2.11 GeV in the cross sections. The bump is not well reproduced by theoretical calculations introducing a nucleon resonance with J<or=3/2. This result suggests that the bump might be produced by a nucleon resonance possibly with J>or=5/2 or by a new reaction process, for example, an interference effect with the phi photoproduction having a similar bump structure in the cross sections.

Near-threshold photoproduction of Lambda(1520) from protons and deuterons

Photoproduction of Lambda(1520) with liquid hydrogen and deuterium targets was examined at photon energies below 2.4 GeV in the SPring-8 LEPS experiment. For the first time, the differential cross sections were measured at low energies and with a deuterium target. A large asymmetry of the production cross sections from protons and neutrons was observed at backward K+/0 angles. This suggests the importance of the contact term, which coexists with t-channel K exchange under gauge invariance. This interpretation was compatible with the differential cross sections, decay asymmetry, and photon beam asymmetry measured in the production from protons at forward K+ angles.

Search for a light pseudoscalar particle in the decay K_{L};{0}-->pi;{0}pi;{0}X

We performed a search for a light pseudoscalar particle X in the decay K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma with the E391a detector at KEK. Such a particle with a mass of 214.3 MeV/c;{2} was suggested by the HyperCP experiment. We found no evidence for X and set an upper limit on the product branching ratio for K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma of 2.4x10;{-7} at the 90% confidence level. Upper limits on the branching ratios in the mass region of X from 194.3 to 219.3 MeV/c;{2} are also presented.

Cross sections and beam asymmetry for K;{+}Sigma;{*-} photoproduction from the deuteron at E_{gamma}=1.5-2.4 GeV

The Sigma(1385) resonance, or Sigma;{*}, is well known as part of the standard baryon decuplet with spin J=3/2. Measurements of the reaction gammap-->K;{+}Sigma;{*0} are difficult to extract due to overlap with the nearby Lambda(1405) resonance. However, the reaction gamman-->K;{+}Sigma;{*-} has no overlap with the Lambda(1405) due to its charge. Here we report the first measurement of cross sections and beam asymmetries for photoproduction of the Sigma;{*-} from a deuteron target. The cross sections at forward angles range from 0.4 to 1.2 mub, with a broad maximum near E_{gamma} approximately 1.8 GeV. The beam asymmetries are negative, in contrast with positive values for the gamman-->K;{+}Sigma;{-} reaction.

Hypoxia appears at pre-arthritic stage and shows co-localization with early synovial inflammation in collagen induced arthritis

OBJECTIVE

The presence of hypoxia in rheumatoid synovium has been well known, but exact correlation between hypoxia and synovitis is unclear. The aim of our study was to investigate the time and spatial relationship and the correlation of severity between hypoxia and synovitis in pre-arthritic or early stage of inflammatory joint disease.

METHODS

DBA/1J mice were injected intradermally with type II collagen and adjuvant solution to induce arthritis; mice injected with only adjuvant were used as a control group. CIA and control mice were sacrificed weekly after the injection to evaluate serial pathological changes. H&E stain and hydroxyprobe-1 stain were performed to look at the status of inflammation and hypoxia.

RESULTS

In serial observations of tissue pathology, we could note the inflammation of synovium developing a week after the injection of type II collagen. Hypoxic change, measured by the hydroxyprobe-1 stain, was also identified in synovium as early as 1 week after the collagen injection, prior to clinically evident arthritis. In addition, we could observe that inflammation and hypoxia co-localize in the synovium and there was a positive correlation between the severity of hypoxia and the degree of synovitis.

CONCLUSION

Our results demonstrate that hypoxia takes place in synovium at the pre-arthritic stage of disease and have a close spatial relationship and a positive severity correlation with synovitis.

Retrobulbar optic neuritis and meningoencephalitis following progressive outer retinal necrosis due to CMV in a patient with AIDS

We report on a 34-year-old male patient with AIDS who developed retrobulbar optic neuritis and meningoencephalitis following bilateral progressive outer retinal necrosis (PORN) caused by cytomegalovirus (CMV). This case documents the presumed association of PORN with retrobulbar optic neuritis, and CMV meningoencephalitis in an AIDS patient.

Behcet's disease associated with bone marrow failure in Korean patients: clinical characteristics and the association of intestinal ulceration and trisomy 8

OBJECTIVES

The aim of this study was to determine the clinical characteristics of Behcet's disease (BD) associated with bone marrow failure (BMF), classified as conditions such as myelodysplastic syndrome (MDS) or aplastic anaemia (AA), in Korea.

METHODS

A retrospective analysis was made of 13 patients with BD associated with BMF (MDS 8 cases, AA 5 cases) and 66 patients with BD not associated with BMF. These patients all fulfilled the diagnostic criteria of the international BD study group.

RESULTS

BD patients with BMF showed significantly lower leucocyte count, haemoglobin level and platelet count when compared with patients without BMF (P < 0.001). BD patients with BMF had significantly higher serum CRP level at the time of BD diagnosis compared with patients without BMF (P = 0.03). Intestinal lesions were more frequent in BD patients with BMF than those without BMF (61.5% vs 13.6%, P = 0.001). Cytogenetic abnormality was observed in 90.9% of BD patients with BMF. Of the cytogenetic abnormalities, trisomy 8 was most common, occurring in 70% of the patients. In four patients with refractory BD associated with BMF, successful treatment of BMF by haematopoietic stem cell transplantation resulted in clinical remission of BD.

CONCLUSIONS

Our study indicates that intestinal ulceration is a characteristic finding in BD associated with BMF. It also suggests that cytogenetic aberration, especially trisomy 8, may play an important role in the pathogenesis of BD associated with BMF.

Search for the Decay K L0-->pi0nu nu[over]

We performed a search for the K L0-->pi0nu nu[over] decay at the KEK 12-GeV proton synchrotron. No candidate events were observed. An upper limit on the branching ratio for the decay was set to be 6.7 x 10(-8) at the 90% confidence level.

[Herpes simplex virus type 1 ICP27 induces apoptotic cell death by increasing intracellular reactive oxygen species]

HSV-1 ICP27, an immediate early protein of herpes simplex virus type 1, is involved in viral replication, transcriptional activation, RNA stability, apoptosis, and reactivation from viral latency. The reactivation from viral latency is closely related to apoptosis and oxidative stress. To understand the effect of ICP27 upon apoptosis, we tested for cell death of ICP27-expressing cells (3-3) in the presence of hydrogen peroxide. Under oxidative stress, 3-3 cells were sensitive to death, displaying typical apoptosis features such as oligonucleosomal DNA fragmentation, chromatin condensation, and G0/G1 accumulation. To dissect the sensitizing mechanism of ICP27 in apoptosis, we analyzed the level of intracellular reactive oxygen species (ROS) in 3-3 cells. We found that 3-3 cells exhibited increased ROS levels compared to Vero cells devoid of ICP27. We also observed that the increased levels of intracellular ROS in 3-3 cells were caused by disturbances in antioxidant enzymes. In 3-3 cells, the elevated ROS increased the AP-1 activity, subsequently the expression of Bax increased, and the expression of Bcl2 was reduced. In addition, 3-3 cells were sensitive to various apoptotic agents. Taken together, these results indicate that HSV-I ICP27 sensitizes the cells to apoptosis by elevating the intracellular levels of ROS.

Role of hypoxia-inducible factor-1alpha in hypoxia-induced expressions of IL-8, MMP-1 and MMP-3 in rheumatoid fibroblast-like synoviocytes

OBJECTIVES

Hypoxia-inducible factor-1alpha (HIF-1alpha) is a master regulator in the cellular response to hypoxic conditions, and rheumatoid synovial tissue is known to exist under hypoxic conditions. Therefore, this study was conducted to determine the contribution of HIF-1alpha to hypoxia-induced MMP and cytokine production in fibroblast-like synoviocytes (FLS).

METHODS

RA FLS were transfected with either a plasmid that expresses HIF-1alpha or an empty vector as a control, and then cultured under normoxia (21% O(2)). Also, FLS were transfected with either HIF-1alpha small interfering RNA (siRNA) or control siRNA, and cultured under hypoxic conditions (1% O(2)). Following transfection, the amounts of MMP and cytokine mRNAs and HIF-1alpha protein were examined using real-time RT-PCR and western blotting, respectively.

RESULTS

The expression of HIF-1alpha, MMP-1, MMP-3, IL-6 and IL-8 was markedly enhanced in FLS that were cultured under hypoxia. We confirmed that transient transfection of HIF-1alpha overexpressing vector or siRNA had occurred using western blotting, and in vitro studies conducted using FLS transfected with HIF-1alpha overexpression vector showed that they had significantly increased MMP-1, MMP-3 and IL-8 expression levels. Further, hypoxia-induced MMP-3 expression was significantly attenuated by knock-down of HIF-1alpha, whereas hypoxia-induced IL-8 or MMP-1 expression was not significantly repressed by HIF-1alpha siRNA.

CONCLUSIONS

Hypoxia-induced MMP-3 expression is exclusively regulated by HIF-1alpha, and hypoxia-induced MMP-1 or IL-8 expression appears to have salvage pathways other than the HIF-1alpha pathway. Together, these data provide new insight regarding the mechanism by which hypoxia participates in joint inflammation and destruction in RA.

Activated Notch1 interacts with p53 to inhibit its phosphorylation and transactivation

We propose a biochemical mechanism for the negative role of Notch signaling on p53 transactivation function. Expression of the intracellular domain of human Notch1 (Notch1-IC) inhibits the expression of p53-responsive genes p21, mdm2, and bax in HCT116 p53(-/-) cells. Furthermore, Notch1-IC expression inhibits the phosphorylation of ectopically expressed p53 in HCT116 p53(-/-) cells as well as the phosphorylation of endogenous p53 in UV-treated HCT116 p53(+/+) cells. Transcriptional downregulation of p53-responsive genes by Notch1-IC was confirmed both by chromatin immunoprecipitation assay and Northern blot analysis. We found the intracellular interaction between Notch1-IC and p53 in HCT116 p53(+/+) cells and suggest that activated Notch1 interaction with p53 is an important cellular event for the inhibition of p53-dependent transactivation. The N-terminal fragment of Notch1-IC, which can interacts with p53, inhibits p53 phosphorylation and represses p53 transactivation. In addition, Notch signaling downregulated p53-dependent apoptosis induced by UV irradiation.

Differential cross section and photon-beam asymmetry for the gamma n --> K+ Sigma- reaction at E gamma = 1.5-2.4 GeV

Differential cross sections and photon-beam asymmetries have been measured for the gamma n --> K+ Sigma- and gamma p --> K+Sigma0 reactions separately using liquid deuterium and hydrogen targets with incident linearly polarized photon beams of E gamma = 1.5-2.4 GeV at 0.6 < cos ThetacmK< 1. The cross section ratio of sigma K+ Sigma-/sigma K+ Sigma0, expected to be 2 on the basis of the isospin 1/2 exchange, is found to be close to 1. For the K+ Sigma- reaction, large positive asymmetries are observed, indicating the dominance of K* exchange. The large difference between the asymmetries for the K+ Sigma- and K+ Sigma0 reactions cannot be explained by simple theoretical considerations based on Regge model calculations.

Near-threshold diffractive psi-meson photoproduction from the proton

Photoproduction of a phi meson on protons was studied by means of linearly polarized photons at forward angles in the low-energy region from threshold to Egamma = 2.37 GeV. The differential cross sections at t = -|t|min do not increase smoothly as Egamma increases but show a local maximum at around 2.0 GeV. The angular distributions demonstrate that phi mesons are photoproduced predominantly by helicity-conserving processes, and the local maximum is not likely due to unnatural-parity processes.

Production of the neutron-rich hypernucleus 10LambdaLi in the (pi-,K+) double charge-exchange reaction

In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.

Efficacy of amblyopia therapy initiated after 9 years of age

AIMS/PURPOSE

To evaluate the efficacy of occlusion therapy initiated after 9 years of age.

METHODS

A total of 16 amblyopes of 9 years or older (range, 9.0-14.5 years; mean, 10.5 years) with a difference in visual acuity of over two lines between the eyes alter 4 weeks of first full-time spectacle wear were included. None of the children had undergone a previous ocular examination, had ever worn spectacles, received occlusion therapy, or had strabismus surgery. Initial worst visual acuity after 4 weeks of full-time spectacle wear was 20/100 in three patients, between 20/80 and 20/40 in 11 patients, and 20/30 in two patients. Full-time occlusion was performed in 14 patients and part-time occlusion in two patients.

RESULTS

The final visual acuity of 15 out of 16 patients (94%) improved at least two lines. The final visual acuities ranged from 20/30 to 20/20 in 14 patients, 20/40 in one patient, and 20/50 in one remaining patient who began amblyopia therapy at 14.5 years of age, with the poorest compliance among the patients.

CONCLUSIONS

Occlusion therapy for anisometropic and strabismic amblyopia can be successful even if initiated after the age of 9 years.

The number of CD8+ T cells and NKT cells increases in the aqueous humor of patients with Behçet's uveitis

To determine whether there are differences in the immunopathogenesis of different endogenous uveitis syndromes, the phenotypic characteristics of immune cells were analysed among patients with endogenous uveitis. The aetiology of the uveitis included idiopathic recurrent acute anterior uveitis (18 patients), idiopathic intermediate uveitis (13 patients), Behçet's uveitis (17 patients), Vogt-Koyanagi-Harada syndrome (7 patients), and so on. Flow cytometric analysis was performed using immune cells of the aqueous humor and the peripheral blood during the active phase of intraocular inflammation, and monoclonal antibodies to CD3, CD4, CD8, CD14, CD19, CD56, TCR gammadelta, pan TCR alphabeta and Valpha24. CD8+ T cells were predominant in the aqueous humor of the patients with Behçet's uveitis, whereas CD4+ T cells were mainly found in the aqueous humor of patients other than those with Behçet's uveitis. The number of NKT (CD3+CD56+) cells was significantly higher both in the aqueous humor and the peripheral blood of the patients with Behçet's uveitis compared with the other groups (P < 0.05). CD8+CD56+ cells were the predominant subtype of the increased NKT cells in patients with Behçet's uveitis. In addition, intraocular infiltration of CD14+ cells significantly differed among the uveitis patients (P < 0.05). These results suggest that the immunopathogenesis of endogenous uveitis can vary between syndromes, and that CD8+CD56+ NKT cells may play an important role in the immunopathogenesis of Behçet's uveitis.

Radon concentrations in groundwater in Busan measured with a liquid scintillation counter method

In this paper, we present the first measurement of radon concentrations in drinking groundwater from private and public deep-bored wells located in the south-eastern area of Korea. The measurements were carried out on 439 samples by using a liquid scintillation method. The results show that the radon concentrations of the samples range from 0 to about 300 Bq l(-1). We find that Sasang ward shows the highest median value of radon concentration among 13 different wards, while Jung ward has the lowest. We find that the radon concentrations are highly dependent on the type of geological rock aquifers.

Beam-polarization asymmetries for the p(gamma-->, K+)Lambda and p(gamma-->, K+)Sigma(0) reactions for E(gamma)=1.5-2.4 GeV

Beam polarization asymmetries for the p(gamma-->,K+)Lambda and p(gamma-->,K+)Sigma(0) reactions are measured for the first time for E(gamma)=1.5-2.4 GeV and 0.6<cos((theta(c.m.)(K+))<1.0 by using linearly polarized photons at the Laser-Electron-Photon facility at SPring-8 (LEPS). The observed asymmetries are positive and gradually increase with rising photon energy. The data are not consistent with theoretical predictions based on tree-level effective-Lagrangian approaches. Including the new results in the development of the models is, therefore, crucial for understanding the reaction mechanism and to test the presence of baryon resonances which are predicted in quark models but are thus far undiscovered.

Evidence for a narrow S = +1 baryon resonance in photoproduction from the neutron

The gamman-->K(+)K(-)n reaction on 12C has been studied by measuring both K+ and K- at forward angles. A sharp baryon resonance peak was observed at 1.54+/-0.01 GeV/c(2) with a width smaller than 25 MeV/c(2) and a Gaussian significance of 4.6sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic five-quark state (uuddsmacr;) that decays into a K+ and a neutron. The resonance is consistent with the lowest member of an antidecuplet of baryons predicted by the chiral soliton model.

Observation of a (6)(LambdaLambda)He double hypernucleus

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.

Production of (4)(double Lambda)H hypernuclei

An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.

Tob-mediated cross-talk between MARCKS phosphorylation and ErbB-2 activation

The biochemical path for the activation of ErbB-2 by PKC activator was investigated in MDA-MB-231 human breast cancer cells. We found that PMA-induced phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS) increased its binding with Tob that exerts an anti-proliferative effect through the binding with ErbB-2. The phosphorylation site domain (PSD) of MARCKS was relevant to its interaction with Tob. Decreased binding of Tob with ErbB-2 and subsequent activation of ErbB-2 were observed in MDA-MB-231 cells in response to PMA treatment. The present study proposes that MARCKS phosphorylation by PKC removes Tob from ErbB-2 by increasing its binding affinity with Tob, and thereby activates the ErbB-2 mediated signal transduction.

Translational suppression by hammerhead ribozymes and inactive variants in S. cerevisiae

The activity of hammerhead ribozymes in S. cerevisiae was assessed using two ribozymes that were designed to intramolecularly attack the hepatitis B viral X mRNA. The ribozymes effectively suppressed the expression of the X-lacZ fusion gene, when they were inserted at the 5' end of the X mRNA. The ribozymes cleaved the target RNA efficiently at the targeted phosphodiester bond, but the inactive mutants carrying G5-to-A substitution in the core did not, as the total RNA preparations of yeast extracts was assayed by primer extension. These G5A mutants, however, exerted the suppression as effectively as the wild-type ribozymes. The results, with several mutations introduced to a ribozyme, suggested that either mere formation of hammerhead-like structures with the three stems, or the formation of any two stems, could inhibit translation. Thus, the hammerhead-like structures, leading to cleavage or not, could effectively suppress translation, especially when formed around the initiation codon. The G5-to-A and U7-to-G mutations and replacement of the stem-II hairpin tetraloop did not appear to affect the formation of the inhibitory structure(s). The inhibition that was observed when stems I and III were directly connected without a loop or with a stem II hairpin was completely relieved when they were connected with only the loop of stem II (not containing the stem portion).

Expression of murine poly(A) binding protein II gene in testis

The poly(A) binding protein II gene (PAB II) has been highly conserved among mouse, bovine, and human. The promoter region of the murine PAB II gene (mPAB II) was investigated in this study. Primer extension analysis demonstrated that there are multiple sites for starting transcription. The promoter region of mPAB II gene contains a CpG island but lacks a TATA box, suggesting that the mPAB II mRNA is transcribed by a TATA-less promoter. Two transcription factor binding sites flanking the major transcription start site were confirmed by gel shift assay. The transcription level of the mPAB II gene in testis increases during spermatogenesis, and mPAB II protein accumulates densely in the nuclei of spermatocytes and round spermatids.