Differential Cross Section and Photon-Beam Asymmetry for the γ[over →]p → π^{-}Δ^{++}(1232) Reaction at Forward π^{-} Angles for E_{γ}=1.5-2.95 GeV

Differential cross sections and photon-beam asymmetries for the γ[over →]p→π^{-}Δ^{++}(1232) reaction have been measured for 0.7<cosθ_{π}^{c.m.}<1 and E_{γ}=1.5-2.95  GeV at SPring-8/LEPS. The first-ever high statistics cross-section data are obtained in this kinematical region, and the asymmetry data for 1.5<E_{γ}(GeV)<2.8 are obtained for the first time. This reaction has a unique feature for studying the production mechanisms of a pure uu[over ¯] quark pair in the final state from the proton. Although there is no distinct peak structure in the cross sections, a non-negligible excess over the theoretical predictions is observed at E_{γ}=1.5-1.8  GeV. The asymmetries are found to be negative in most of the present kinematical regions, suggesting the dominance of π exchange in the t channel. The negative asymmetries at forward meson production angles are different from the asymmetries previously measured for the photoproduction reactions producing a dd[over ¯] or an ss[over ¯] quark pair in the final state. Advanced theoretical models introducing nucleon resonances and additional unnatural-parity exchanges are needed to reproduce the present data.

Interference Effect between ϕ and Λ(1520) Production Channels in the γp→K^{+}K^{-}p Reaction near Threshold

The ϕ-Λ(1520) interference effect in the γp→K^{+}K^{-}p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between ϕ and Λ(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K^{+}K^{-} pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the sqrt[s]=2.1  GeV bump structure in forward differential cross sections for ϕ photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.

Prostacyclin promotes oligodendrocyte precursor recruitment and remyelination after spinal cord demyelination

Adult oligodendrocyte precursor cells (OPCs) are located adjacent to demyelinated lesion and contribute to myelin repair. The crucial step in remyelination is the migration of OPCs to the demyelinated area; however, the mechanism of OPC migration remains to be fully elucidated. Here we show that prostacyclin (prostaglandin I2, PGI2) promotes OPC migration, thereby promoting remyelination and functional recovery in mice after demyelination induced by injecting lysophosphatidylcholine (LPC) into the spinal cord. Prostacyclin analogs enhanced OPC migration via a protein kinase A (PKA)-dependent mechanism, and prostacyclin synthase expression was increased in the spinal cord after LPC injection. Notably, pharmacological inhibition of prostacyclin receptor (IP receptor) impaired remyelination and motor recovery, whereas the administration of a prostacyclin analog promoted remyelination and motor recovery after LPC injection. Our results suggest that prostacyclin could be a key molecule for facilitating the migration of OPCs that are essential for repairing demyelinated areas, and it may be useful in treating disorders characterized by demyelination.

Spin-density matrix elements for γp→K*0Σ+ at Eγ=1.85-3.0 GeV with evidence for the κ(800) meson exchange

The exclusive reaction γp→K(+)π(-)Σ(+) was measured for the first time using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. Angular distributions in the rest frame of the K(+)π(-) system were fitted to extract spin-density matrix elements of the K(*0) decay. The measured parity spin asymmetry shows that natural-parity exchange is dominant in this reaction. This result clearly indicates the need for t-channel exchange of the κ(800) scalar meson.

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.

HtrA2/Omi-immunoreactive intraneuronal inclusions in the anterior horn of patients with sporadic and Cu/Zn superoxide dismutase (SOD1) mutant amyotrophic lateral sclerosis

AIMS

HtrA2/Omi is a mitochondrial serine protease that promotes the apoptotic processes, but the relationship between HtrA2/Omi and amyotrophic lateral sclerosis (ALS) is still unknown. The purpose of the present study was to determine whether abnormal expression of HtrA2/Omi occurs in patients with ALS.

METHODS

We prepared autopsied spinal cord tissues from 7 control subjects, 11 patients with sporadic ALS (SALS) and 4 patients with Cu/Zn superoxide dismutase (SOD1)-related familial ALS (FALS). We then performed immunohistochemical studies on HtrA2/Omi using formalin-fixed, paraffin-embedded sections from all of the cases.

RESULTS

In the control subjects, the anterior horn cells were mildly to moderately immunostained with HtrA2/Omi. In the patients with SALS, strong HtrA2/Omi immunoreactivity was found in some skein-like inclusions and round hyaline inclusions as well as many spheroids, but Bunina bodies were immunonegative for HtrA2/Omi. In the patients with SOD1-related FALS, Lewy body-like hyaline inclusions were observed in three cases and conglomerate inclusions were observed in the remaining case, and both types of inclusions were intensely immunopositive for HtrA2/Omi.

CONCLUSIONS

These results suggest that abnormal accumulations of HtrA2/Omi may occur in several types of motor neuronal inclusions in the anterior horn from SALS and SOD1-linked FALS cases, and that HtrA2/Omi may be associated with the pathogenesis of both types of ALS.

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.

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.

Aberrantly spliced alpha-dystrobrevin alters alpha-syntrophin binding in myotonic dystrophy type 1

BACKGROUND

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder caused by a CTG repeat expansion in the DMPK gene. Aberrant messenger RNA (mRNA) splicing of several genes has been reported to explain some of the symptoms in DM1, but the cause of muscle wasting is still unknown. By contrast, many forms of muscular dystrophy are caused by abnormalities of the dystrophin-glycoprotein complex (DGC). alpha-Dystrobrevin is a key component of the DGC in striated muscle and plays important roles in maturation and signal transduction by interacting with alpha-syntrophin. The goal of this study was to investigate alternative splicing of alpha-dystrobrevin in DM1 and examine alpha-syntrophin binding of different alpha-dystrobrevin splice isoforms.

METHODS

Splicing patterns of alpha-dystrobrevin in DM1 muscle were studied by reverse-transcriptase PCR. Expression of the variant splice isoform was examined by immunoblotting and immunohistochemistry. Alternatively spliced isoforms were expressed in cultured cells to investigate interaction with alpha-syntrophin. alpha-Syntrophin expression was examined by immunoblotting.

RESULTS

alpha-Dystrobrevin mRNA including exons 11A and 12 was increased in both skeletal and cardiac muscle of DM1 patients. The aberrantly spliced alpha-dystrobrevin isoform was localized to the sarcolemma, and showed increased binding with alpha-syntrophin. Furthermore, levels of alpha-syntrophin associated with the DGC were increased in DM1 muscle.

CONCLUSION

Alternative splicing of alpha-dystrobrevin is dysregulated in myotonic dystrophy type 1 (DM1) muscle, resulting in changes in alpha-syntrophin binding. These results raise the possibility that effects on alpha-dystrobrevin splicing may influence signaling in DM1 muscle cells.

Neuronal intranuclear hyaline inclusion disease with rapidly progressive neurological symptoms

This report describes a male patient who presented with symptoms suggestive of spinocerebellar degeneration and who died of respiratory failure at the age of 7 years but was diagnosed, at autopsy, as having neuronal intranuclear hyaline inclusion disease. Neuronal intranuclear hyaline inclusion disease is a progressive and degenerative disease; diagnosis is possible only by neuropathological analysis. This is a rare disorder; few cases with early childhood onset and rapidly progressive neurologic symptoms have been documented. According to previous reports, most neurons in the central nervous system exhibited intranuclear eosinophilic inclusion bodies; neuronal depletion appeared to be restricted to the cerebellar cortex and the medullary inferior olivary nuclei, consistent with the fact that clinical deficit appears to correspond to the site of neuronal depletion and not to where eosinophilic bodies are detected. Immunohistochemical analysis revealed that these inclusions were positive for ubiquitin. The case presented herein clearly indicates that neuronal intranuclear hyaline inclusion disease should be considered as a differential diagnosis of cases involving spinocerebellar degeneration with childhood onset.

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.

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.

Excitation and decay of the isovector giant monopole resonances via the 208Pb(3He,t p) reaction at 410 MeV

The excitation and subsequent proton decay of the isovector spin-flip giant monopole resonance (IVSGMR) is studied via the 208Pb(3He,t) reaction at 410 MeV. In the inclusive spectrum (60+/-5)% of the non-energy-weighted sum-rule strength for this 2 variant Planck's over 2h omega resonance was found in the region 29<Ex(208Bi)<51 MeV. The central excitation energy and width of the IVSGMR are 37+/-1 MeV and 14+/-3 MeV, respectively. It is found that the branching ratio for proton decay is (52+/-12)% and that the deep neutron-hole states in 207Pb are strongly fed.

Decreased hepatobiliary transport of methotrexate in adjuvant arthritis rats

1. We investigated the difference in hepatobiliary transport of methotrexate in normal and adjuvant arthritis (AA) rats and substantiated the expression level of multidrug resistance-associated protein 2 (MRP2) in the liver. 2. Biliary clearance of methotrexate in normal and AA rats was calculated from plasma concentrations and biliary excretion following intravenous infusion and hepatic uptake clearance was estimated from an integration plot using methotrexate concentrations in plasma and liver. 3. Biliary clearance of methotrexate in AA rats was 2.30 +/- 0.23 ml min(-1) kg(-1) (mean SD) and significantly lower than in normal rats (8.42 +/- 0.81 ml min(-1) kg(-1)). The uptake clearance of methotrexate in AA rats was also lower than in normal rats (0.138 versus 0.278 ml min(-1) g liver(-1)). 4. MRP2 in the liver was detected by fluorescein isothiocyanate-labelled antibody and visualized using a confocal laser microscope system. The expression level of MRP2 in AA rats was very low compared with normal rats, indicating a down-regulation in AA rats. 5. In conclusion, biliary clearance of methotrexate was decreased due to the lower activities in both uptake and canalicular secretion, suggesting that several active transporters in the liver, including MRP2, are down-regulated in AA rats.

Recovery process of arthritis induced by 6-sulfanilamidoindazole (6SAI) in rats

6-Sulfanilamidoindazole (6SAI) is known to induce not only an acute arthritis but also serositis and arteritis which resemble those induced by some vasodilators in rats. In this study, the recovery process of ankle lesions was examined histopathologically for up to 12 weeks of recovery period in rats bearing arthritis induced by administration of 6SAI (500 mg/kg) for 2 weeks. At 2 weeks of 6SAI-treatment, exudative synovitis and exudative/edematous periarthritis with marked formation of granulation tissues and periosteal reactive bone formation were noted in the ankles, but no remarkable neutrophil infiltration was detected in those lesions. The ankle swelling induced by 6SAI diminished by 4 weeks of recovery period, and the elevated plasma fibrinogen levels were normalized by 2 weeks of recovery period. Although fibrosis and newly-formed periosteal bone were still observed after 2 weeks of recovery period, no inflammatory lesion was detected at that point. At 4 or 12 weeks of recovery periods, the ankles showed an almost normal appearance. These results indicate that 6SAI-induced arthritis is reversible in nature and does not develop into chronic phase.

Optimal doses of paclitaxel and carboplatin combination chemotherapy for ovarian cancer: a phase I modified continual reassessment method study

BACKGROUND

A multicenter, phase I study of combination therapy with paclitaxel and carboplatin for epithelial ovarian cancer was conducted to determine the safety and recommended dosages for Japanese women.

METHODS

Paclitaxel was administered intravenously over a 3-h period, followed by carboplatin administered intravenously over a 1.5-h period. A modified continual reassessment method (mCRM) was used in two treatment arms to establish the maximum tolerated dose (MTD) and recommended doses of the combination. In group A, the dose of paclitaxel (175 mg/m2) was constant and the dose of carboplatin was increased from 4 to 7 in terms of the target area under the plasma concentration-versus-time curve (AUC). In group B, the dose of carboplatin was constant (AUC 6) and paclitaxel was administered at two dose levels (160 and 175 mg/m2). In both groups, the carboplatin dose was limited to a maximum of 800 mg/body for each administration.

RESULTS

Because the calculated probability of toxicity was greatest at a dose of paclitaxel 175 mg/m2 and carboplatin AUC 7, this dose was designated the MTD in group A. Based on this result, treatment in group B was initiated at doses of paclitaxel of 160 mg/m2 and carboplatin AUC 6. While the dose of paclitaxel was escalated to 175 mg/m2, the safety of the combination was confirmed. The most frequent adverse effect was neutropenia, which resolved promptly with the appropriate use of granulocyte-colony stimulating factor (G-CSF). No other severe hematologic or nonhematologic toxicities were observed.

CONCLUSIONS

Our study demonstrated that the recommended dose for this combination regimen should be paclitaxel 175 mg/m2 plus carboplatin AUC 6 (maximum dose, 800 mg/body).

Improvement of anti-Hu-associated paraneoplastic sensory neuropathy after chemoradiotherapy in a small cell lung cancer patient

A 66-year-old man developed progressive painful dysesthesia in his hands and feet over 3 months. His vibration sense was impaired and sensory nerve action potentials of the limbs were not evoked. Biopsy of the peroneal nerve revealed sensory neuropathy. Positive anti-Hu antibody facilitated delineation of a right hilar mass and a metastatic lymph node in thoracic CT scan. He was diagnosed as small cell lung cancer associated with paraneoplastic sensory neuropathy. A complete response was achieved through chemotherapy (carboplatin and etoposide) and subsequent radiation therapy. Notably, his neurological conditions, although not changed during the hospitalization, gradually improved afterwards.

Leptomeningeal signet-ring cell carcinomatosis presenting with ophthalmoplegia, areflexia and ataxia

We report a very rare case of occult leptomeningeal carcinomatosis (LC) in whom repeated cytological examination did not show malignant cells in cerebrospinal fluid (CSF) and the primary focus was not discovered by extensive survey. The patient presented with ophthalmoplegia, ataxia and areflexia mimicking Miller Fisher syndrome (MFS) at the initial stage, and later, the clinical profile and laboratory findings including CSF examination simulated tuberculous meningitis. Postmortem autopsy disclosed metastatic signet-ring cell carcinoma infiltrating into cranial nerves and leptomeninges. We would like to emphasize that LC sometimes shows symptoms and signs similar to MFS or tuberculous meningitis.

Dipole excitation of alpha clusters in (6)Li and (7)Li

Dipole excitations in highly excited energy regions of (6)He and (7)He nuclei were investigated via the ((7)Li,(7)Be) reaction with an incident energy of 65A MeV at forward scattering angles. The resonances at Q approximately equal to -30 MeV observed commonly for both (6)Li and (7)Li targets were found to be excited via both spin-flip and spin-nonflip transitions with DeltaL = 1. Based on the observed excitation energy, width, and cross section of each resonance, the relevant resonances are inferred to be analogs of the dipole resonances of alpha clusters in the (6)Li and (7)Li nuclei.

Copper chaperone for superoxide dismutase co-aggregates with superoxide dismutase 1 (SOD1) in neuronal Lewy body-like hyaline inclusions: an immunohistochemical study on familial amyotrophic lateral sclerosis with SOD1 gene mutation

The copper chaperone for superoxide dismutase (CCS) interacts with Cu/Zn-binding superoxide dismutase 1 (SOD1) specifically and delivers copper to SOD1. To determine the role of the CCS-SOD1 interaction in the pathogenesis of SOD1-mutated familial amyotrophic lateral sclerosis (FALS) patients, we produced an affinity-purified rabbit antibody against CCS and investigated the immunohistochemical localization of both CCS and SOD1 in neuronal Lewy body-like hyaline inclusions (LBHIs) in the spinal cords of two FALS patients with a two-base pair deletion at codon 126 in the SOD1 gene and three FALS patients with an Ala to Val substitution at codon 4. The LBHIs in anterior horn cells from the five FALS patients showed identical immunoreactivities for CCS: the reaction product deposits with the antibody against CCS were generally restricted to the periphery of the core and halo-type LBHIs. The localizations of the immunoreactivities for CCS and SOD1 were similar in the inclusions: both CCS and SOD1 colocalized in neuronal LBHIs in the five mutant SOD1-linked FALS patients. Our results suggest that the specific interaction and aggregation of CCS-SOD1 (probably CCS-mutant SOD1) in SOD1-mutated FALS patients may amplify the formation of inclusions and emphasize a more marked mutant SOD1-mediated toxicity.

Dynamics of antigen-specific helper T cells at the initiation of airway eosinophilic inflammation

Bronchial asthma is characterized by chronic eosinophilic inflammation of the bronchial mucosa in which Th2 cells play crucial roles. Ovalbumin-reactive Th2 clones were labeled with a fluorescent-probe then infused into unprimed mice to elucidate the dynamics of antigen-specific T cells involved in allergic inflammation. Infiltration of not only labeled antigen-specific T cells, but also unlabeled nonspecific CD4(+) T cells into the bronchial mucosa following inhaled antigen challenge was detectable under confocal microscopy and flow cytometry. Accordingly, labeled T cells in the spleen were decreased, whereas those in hilar lymph nodes were increased upon antigen challenge. Approximately 45% of antigen-specific T cells that migrated into the lungs bore CD25, while another early activation marker, CD69, was expressed on 80% of the migrated T cells. Accordingly, antigen challenge to the mice induced in situ proliferation of antigen-specific T cells as well as bronchial epithelial cells in the lungs. Expression of vascular cell adhesion molecule (VCAM)-1, but not intercellular adhesion molecule (ICAM)-1, on the vascular endothelium in the lungs was enhanced following antigen challenge. Nevertheless, treatment with anti-VCAM-1 antibody, and also anti-ICAM-1 antibody strongly suppressed the accumulation of T cells, suggesting that both VCAM-1 and ICAM-1 are essential for antigen-stimulated T cell mobilization into peripheral tissues. Our current study visualized the kinetics and the mechanism of antigen-specific T cell migration in response to local challenge with a protein antigen.

Reduction of metallothioneins promotes the disease expression of familial amyotrophic lateral sclerosis mice in a dose-dependent manner

We previously reported that abnormal copper release from mutated Cu, Zn-superoxide dismutase (SOD1) proteins might be a common toxic gain-of-function in the pathogenesis of familial amyotrophic lateral sclerosis (FALS) [Ogawa et al. (1997) Biochem. Biophys. Res. Commun., 241, 251-257.]. In the present study, we first examined metallothioneins (MTs), known to bind copper ions and decrease oxidative toxicity, and found a twofold increase in MTs in the spinal cord of the SOD1 transgenic mice with a FALS-linked mutation (G93A), but not in the spinal cord of wild-type SOD1 transgenic mice. We then investigated whether the clinical course of FALS mice could be modified by the reduced expression of MTs, by crossing the FALS mice with MT-I- and MT-II-deficient mice. FALS mice clearly reached the onset of clinical signs and death significantly earlier in response to the reduction of protein expression. These results indicated that the copper-mediated free radical generation derived from mutant SOD1 might be related to the degeneration of motor neurons in FALS and that MTs might play a protective role against the expression of the disease.