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A long-standing controversial issue in the quest to understand the superconductivity in cuprates is the nature of the enigmatic pseudogap region of the phase diagram. Especially important is whether the pseudogap state is a distinct thermodynamic phase characterized by broken symmetries below the onset temperature T∗. Here we report torque-magnetometry measurements of anisotropic susceptibility within the ab planes in orthorhombic YBa2Cu3Oywith exceptionally high precision. The in-plane anisotropy displays a significant increase with a distinct kink at the pseudogap onset temperature T∗, showing a remarkable scaling behaviour with respect to T/T∗in a wide doping range. Our systematic analysis reveals that the rotational symmetry breaking sets in at T∗in the limit where the effect of orthorhombicity is eliminated. These results provide thermodynamic evidence that the pseudogap onset is associated with a second-order nematic phase transition, which differs from the recently reported charge-density-wave transition that accompanies translational symmetry breaking.

Abstract: We have studied metallic phases of the title organic conductors by means of STM at room temperature. An image obtained in the salt with M=Rb is very different from a typical one in the salt with M=Cs. We suggest “vertical stripe” charge ordering in the salt with M=Rb at room temperature, which can naturally explain its anomalous metallic behavior.

The aim of this study was to analyze magnetic resonance imaging (MRI) morphometry and cerebral blood flow (CBF) in patients with hypoxic-ischemic encephalopathy, and determine the viability of such measurements for predicting cerebral outcome. The subjects were 26 patients with histories of cardiopulmonary resuscitation who had subsequently developed encephalopathy. We examined the CBF using stable xenon-computed tomography (Xe-CT) and MR images in the subacute period (8-20 days). Three signal-change patterns in the basal ganglia emerged in the MRI study. The first pattern, isointense areas evident in both the T1-weighted image (T1WI) and the T2-weighted image (T2WI), was observed in four patients with favorable outcomes. The second pattern, iso- or hypointense areas evident in the T1WI and hyperintense areas evident in the T2WI, was observed in six patients with favorable outcomes and three patients with poor outcomes. The third pattern, hyperintense areas evident in both the T1WI and T2WI, was observed in 13 patients with poor outcomes. Hemispheric CBFs were 38.9+/-4.6 (mean (SD)) ml/100 g/min in patients with favorable outcomes and 25.3+/-4.3 ml/100 g/min in patients with poor outcomes (P<0.01). The CBF increase after acetazolamide administration was 13.3+/-3.4 ml/100 g/min in patients with favorable outcomes and 6.8+/-5.6 ml/100 g/min in patients with poor outcomes (P<0.05). The presence of hyperintense lesions in the basal ganglia in T1WI, low hemispheric CBF (<30 ml/100 g/min), and low acetazolamide reactivity (<10 ml/100 g/min) are all factors associated with poor outcome in patients with hypoxic-ischemic encephalopathy.

We report evidence from Raman measurements of local lattice distortions in the cuprates, which are induced at room temperature by varying the hydrostatic pressure and correlate with changes in the superconducting transition temperature. Anomalous nonlinear pressure dependence is observed for almost all Agphonons of the YBa2Cu3O6.5, YBa2Cu3Oover, and YBa2Cu4O8superconducting single crystals, which occurs at pressures where the transition temperature shows also characteristic changes. The results are compared with a similar correlation found between transition temperature and spectral modifications in Bi2Sr2CaCu2O8by pressure and in YBa2Cu3Oxand La2−xSrxCuO4by chemical doping. There are strong indications that the saturation of Tcwith pressure or compositional doping in these cuprates is mainly related with lattice instabilities and probably also with phase separation phenomena.

We investigated the microwave surface impedance in Zn doped YBa2Cu3Oy. For low Zn concentrations, crossover frequency ωpand viscosity η of vortex do not change significantly (at maximum, factor of 2). This is in sharp contrast to the dramatic change in the zero-field quasiparticle scattering time. The robust nature of viscosity on the impurity doping suggests that the quasiparticle scattering time in the vortex core is determined by a different mechanism from that outside the core.

We have investigated the spin state of the one-dimensional edge-sharing chain system Ca2+xY2−xCu5O10with 0≤x≤1.667 by means of the magnetic susceptibility and specific heat measurements, using the large-size single-crystals. It has been found that the magnetic ground state is an antiferromagnetically ordered state for 0≤x≤1.0, while a spin-gap state seems to be formed for x≥1.5. Accordingly, it appears that the quantum critical point is located between x=1.0 and 1.5 in Ca2+xY2−xCu5O10.

Abstract. To clarify the relationship between thallium-201 chloride kinetics and proliferative activity in brain tumours, a single-photon emission tomographic (SPET) study was performed and the results correlated with monoclonal antibody MIB-1 staining of the tumour tissue. ²⁰¹Tl SPET was performed 10 min (early scan) and 2 h (delayed scan) after intravenous administration of ²⁰¹Tl (111 MBq) in 34 intra-axial tumours including 24 malignant tumours, and in 27 extra-axial tumours including one malignant tumour. Tumour ²⁰¹Tl kinetic parameters [early and delayed uptake ratios (ER and DR, respectively), retention index (RI), and the ratio of tumour delayed activity to early activity (Td/Te)] were compared with tumour tissue MIB-1 labelling indices (MIB-1 LI) representative of tumour cell proliferative activity. In the intra-axial tumours, ER and DR and MIB-1 LI were significantly higher in the malignant tumours than in the benign tumours. ER and DR were significantly correlated with MIB-1 LI (P&lt;0.01 and P&lt;0.05, respectively), but RI and Td/Te were not. In the extra-axial benign tumours, ER was as high as that in the intra-axial malignant tumours, while MIB-1 LI was equal to that in the intra-axial benign tumours. There were no significant correlations between any ²⁰¹Tl kinetic parameters and MIB-1 LI. This study indicates that ²⁰¹Tl ER may be the most reliable parameter for predicting the proliferative activity of intra-axial tumours.

The effect of a hydrostatic pressure (up to 6GPa) on the Raman spectra of YBa2Cu3Ox(x = 6.5 and overdoped) single crystals is investigated in the temperature range 77-300 K in connection with all available data in the literature for the other oxygen concentrations. All five strong modes (4Ag+1B1g) are examined for both oxygen doping and compared with previously published results. From the systematic investigation of the phonon spectral characteristics with the application of pressure, the formation or disappearance of the phases is examined. The results provide a spectroscopic support for the changes induced by the hydrostatic pressure on the chain ordering and the corresponding phases.

Using digitonin-permeabilized GH3 cells, we investigated both the release of prolactin (PRL) and changes in the cytoskeleton. We determined that permeabilized GH3 cells released PRL in a dose-dependent manner upon addition of micromolar Ca(2+). Phalloidin, a filamentous actin (F-actin) stabilizing agent, inhibited both Ca(2+)-dependent and -independent PRL release, whereas cytochalasin B, a destabilizing agent, had almost no effect on the release. Observation with a confocal laser scanning microscope revealed that F-actin existed mainly in the cortical region in the quiescent state. Increased cytosolic Ca(2+) induced a change in F-actin distribution: F-actin in the cortical region decreased, whereas F-actin inside the cells increased. This change in F-actin distribution was not observed when phalloidin was added. Addition of cytochalasin B induced patchy F-actin spots, but the pattern of the changes of F-actin distribution did not change. The time course of change in F-actin distribution showed that the F-actin network in the cortical region was reduced within 1 min, and Ca(2+)-dependent release of PRL continued for up to 20 min. These results suggest that the F-actin network near the membrane acts as a barrier to exocytosis and that Ca(2+) directly controls the cytoskeletal changes.

Abstract: Acoustic schwannoma is a slow-growing tumor and usually occurs in adult patients. We report a rare pediatric case of acoustic schwannoma with high proliferative potential. A 10-year-old boy was diagnosed as having a right cerebellopontine angle tumor. The tumor was subtotally resected. Histological examination revealed a typical acoustic schwannoma with a few mitotic figures. Chromosomal analysis showed no abnormality on the long arm of chromosome 22 associated with neurofibromatosis type 2. The lesion regrew rapidly as an acoustic schwannoma, necessitating subtotal resection on three occasions and CyberKnife radiosurgery. The immunohistochemical MIB-1 staining indices of the specimens obtained at the first, second, and third operations were 2.3%, 4.6% and 14.7%, respectively. The immunohistochemical proliferative potential of acoustic schwannoma is discussed.

Background: Despite continued progress in the development of immunosuppressive agents, allograft rejection remains an important cause of morbidity and mortality after liver transplantation. We examined the effect of the deletion variant of hepatocyte growth factor (dHGF) on allograft rejection after liver transplantation. Methods: Male Dark Agouti rats (RT1a) were selected as donors and male Lewis rats (RT1l) as recipients for a rejection model. The recipients were divided into 2 groups after orthotopic liver transplantation (OLTx): in the dHGF group dHGF was given intravenously twice a day (1 mg/kg/day) after OLTx, whereas in the control group vehicle buffer was given intravenously daily twice after OLTx. The survival period, serum chemistry studies, and histopathologic findings were then compared between the 2 groups. Results: The mean survival period after OLTx in the dHGF group was significantly longer than that in the control group (21.4 +/- 1.3 days vs 11.8 +/- 0.4 days, P < .001). On the 10th posttransplant day the serum albumin level significantly improved in the dHGF group (P < .01), and the serum total bilirubin and aspartate aminotransferase levels were significantly lower in the dHGF group (P < .01 and P < .05, respectively). On the 10th posttransplant day a histologic examination revealed no apparent difference in the severity of rejection between the 2 groups. The number of proliferating cell nuclear antigen-positive hepatocytes in the dHGF group significantly increased (P < .01), whereas the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling-positive hepatocytes were significantly reduced in the dHGF group (P < .01) in comparison with those in the control group. Conclusion: dHGF has an antiapoptotic property as well as a proliferative and protective effect on hepatocytes under allograft rejection. dHGF might serve as a novel agent for reducing the harmful effects of hepatic allograft rejection in rats. (Surgery 1999;125:602-7.)

Abstract: Giant cell tumor (GCT) of bone was first established as a distinct clinicopathological radiographic entity in 1940 when Jaffe distinguished it from other lesions containing giant cells. GCT is rare in patients under 15 years of age. We report a case of GCT in a 10-year-old boy whose X-ray films showed osteolysis suggesting a malignant bone tumor. We believe this to be the youngest patient with giant cell bone tumor ever reported in the Japanese literature.

The local magnetic induction is measured in the quasi-two dimensional organic superconductor κ-(BEDT-TTF)2Cu(NCS)2by using a micro Hall probe. The small step is observed on the temperature dependence of the local magnetic induction. This result implies the existence of the first-order phase transition of the vortex system in this organic superconductor as is already reported in high-Tcoxide and other organic superconductors.

The so-called 1/8 effect, namely, the anomalous suppression of superconductivity at the hole concentration per Cu in the CuO2plane, p, ∼ 1/8 has been investigated in the partially Zn-substituted Bi-2212 and Y-123 phases by measuring the Hall effect and the muon spin relaxation ( μSR ). The Hall angle has been found to exhibit large enhancement at p ∼ 1/8 in Bi2Sr2Ca1−xYx(Cu1−yZny)2O8+δwith y=0.025. In YBa2Cu3−2yZn2yO7−δwith y=0.025, anomalous enhancement of the muon spin depolarization has been observed at p ∼ 1/8, indicating that the magnetic correlation between Cu spins is enhanced at p ∼ 1/8. These results support the stripe model and the proposition that the 1/8 effect is common to all high-Tccuprates with the CuO2plane.

During a period of 94 months between 1985 and 1993, 474 hepatic resections were performed in 451 patients, of whom 23 (5 per cent) had cardiac problems: ischaemic heart disease in 16 (previous myocardial infarction in five and angina pectoris in 11), arrhythmic disorders in three, valvular disease in three (previous mitral valve replacement in two) and hypertrophic cardiomyopathy in one. The cardiac patients had a higher incidence of cardiac complications (24 versus0 per cent, P< 0·0001) including two myocardial infarctions, and of non-cardiac complications consisting of postoperative liver failure (16 versus4 per cent, P<0·01) and bile leak (16 versus5 per cent, P= 0·02), as well as hospital death (16 versus3 per cent, P< 0·001). However, long-term survival was similar in the two groups. Patients with preoperative cardiac conditions appear to be at increased risk for early postoperative morbidity and mortality after hepatic resection.