Chemically induced Jahn-Teller ordering on manganite surfaces.

Physical and electrochemical phenomena at the surfaces of transition metal oxides and their coupling to local functionality remains one of the enigmas of condensed matter physics. Understanding the emergent physical phenomena at surfaces requires the capability to probe the local composition, map order parameter fields and establish their coupling to electronic properties. Here we demonstrate that measuring the sub-30-pm displacements of atoms from high-symmetry positions in the atomically resolved scanning tunnelling microscopy allows the physical order parameter fields to be visualized in real space on the single-atom level. Here, this local crystallographic analysis is applied to the in-situ-grown manganite surfaces. In particular, using direct bond-angle mapping we report direct observation of structural domains on manganite surfaces, and trace their origin to surface-chemistry-induced stabilization of ordered Jahn-Teller displacements. Density functional calculations provide insight into the intriguing interplay between the various degrees of freedom now resolved on the atomic level.

Tunable metallicity of the La5/8Ca3/8MnO3(001) surface by an oxygen overlayer.

We studied the surface structure of La_{5/8}Ca_{3/8}MnO_{3}(001) thin films using in situ scanning tunneling microscopy (STM). Atomically resolved STM images reveal that a (sqrt[2]xsqrt[2])R45;{ degrees } reconstructed surface and a (1x1) surface can be converted back and forth through adsorption and desorption of oxygen at the surface. The electrical properties of the surfaces are investigated by scanning tunneling spectroscopy. I-V curves clearly show that the presence of an oxygen overlayer renders the surface insulating while the (1x1) surface without the oxygen overlayer is metallic.

Reemergent metal-insulator transitions in manganites exposed with spatial confinement.

The metal-insulator transition is characterized as a single peak in the temperature-dependent resistivity measurements; exceptions to this have never been seen in any single crystal material system. We show that by reducing a single crystal manganite thin film to a wire with a width comparable to the mesoscopic phase-separated domains inherent in the material, a second and robust metal-insulator transition peak appears in the resistivity versus temperature measurement. This new observation suggests that spatial confinement is a promising route for the discovery of emergent physical phenomena in complex oxides.

Absolute number of circulating CD34+ cells is abnormally low in refractory anemias and extremely high in RAEB and RAEB-t; novel pathologic features of myelodysplastic syndromes identified by highly sensitive flow cytometry.

We scored absolute numbers of circulating CD34+ cells by a highly sensitive triple-color flow cytometric analysis using CD45 monoclonal antibody, CD34 monoclonal antibody and propidium iodide. Forty-one patients with MDS (RA: 27, RARS: 1, RAEB: 6, RAEB-t: 3,CMML: 4), 12 patients with aplastic anemia (AA) and 36 age-adjusted normal subjects were studied. RA had significantly decreased numbers of cells expressing CD34 (0.21 +/- 0.29 x 10(6)/l) compared with normal subjects (0.81 +/- 0.36 x 10(6)/l)(P < 0.001). This low number of CD34+ cells in RA resembles the case of AA (0.39 +/- 0.73 x 10(6)/l). In light-scatter analysis, the CD34+ cells of RA patients were distributed mainly in low forward scatter (FSC) (lymphocyte region). In contrast, the CD34+ cell counts were extremely high in patients with RAEB (46.54 +/- 71.37 x 10(6)/l) and RAEB-t (57.00 +/- 52.36 x 10(6)/l) (P < 0.001) and the CD34+ cells were observed in high FSC (blast region).CMML patients showed moderately increased numbers of CD34+ cells (3.69 +/- 4.64 x 10(6)/l). Thus, there was a distinct difference in cell size and number of circulating CD34+ cells between RA and RAEB/RAEB-t. In univariate and multivariate analysis, a high CD34+ cell count (> or = 1.0 x 10(6)/l) was a poor prognostic factor. This method allows one to distinguish RA from other MDS subtypes more reliably than by morphology alone and provides early signs of progression to acute leukemia.

Microwave Spectrum, Structure, and Nuclear Quadrupole Coupling Constants of 1-Bromo-1-fluoroethane.

The microwave spectrum of 1-bromo-1-fluoroethane, CHBrF-CH(3) and CHBrF-CH(2)D ((79/81)Br), has been studied for the first time from 8 to 41 GHz. A least-squares analysis of the observed a- and b-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows: A = 8979.428(5) MHz, B = 2883.898(3) MHz, C = 2310.535(3) MHz, Delta(J) = 0.74(2) kHz, Delta(JK) = 2.49(3) kHz, Delta(K) = 5.3(5) kHz, delta(J) = 0.146(1) kHz, delta(K) = 2.75(4) kHz, chi(aa) = 493.49(29) MHz, chi(bb) - chi(cc) = -38.89(11) MHz, and ||chi(ab) || = 161.8(28) MHz for the CH(79)BrF-CH(3) species; A = 8979.257(5) MHz, B = 2859.072(3) MHz, C = 2294.572(3), Delta(J) = 0.76(2) kHz, Delta(JK) = 2.51(3) kHz, Delta(K) = 4.5(4) kHz, delta(J) = 0.145(1) kHz, delta(K) = 2.70(4) kHz, chi(aa) = 412.42(27) MHz, chi(bb) - chi(cc) = -32.56 (11) MHz, and ||chi(ab) || = 133.3(3) MHz for the CH(81)BrF-CH(3) species. The structural parameters are calculated from the 24 observed rotational constants, and electronic properties of the carbon-bromine bond in 1-bromo-1-fluoroethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules. The molecular structure of 1-bromo-1-fluoroethane is found to be very close to that of 1,1-difluoroethane except for the C-Br bond. Copyright 1999 Academic Press.

New system for assessing the prognosis of refractory anemia patients.

Refractory anemia (RA) is a very heterogeneous disease regarding biological and clinical features. The International Prognostic Scoring System (IPSS) was useful for assessing the prognosis in the whole group of 219 myelodysplastic syndrome (MDS) patients. However, the IPSS was not sufficient in 132 RA patients. To predict survival and freedom from acute myeloid leukemia (AML) evolution, we investigated individual prognostic factors based on the clinical parameters (age, gender, morphologic features, cytopenias and cytogenetics) of 132 RA patients using univariate and multivariate analyses. Based on the results, we devised a new system for assessing the prognosis of RA patients. In our system, RA patients with pseudo-Pelger-Huët anomalies >/=3% were classified as high risk (12 patients); of patients without pseudo-Pelger-Huët anomalies >/=3%, those with intermediate/poor karyotype according to IPSS, Hb /=10% were classified as intermediate risk (57 patients); and those without high or intermediate risk were classified as low risk (67 patients). In our system, the analyses of both survival times and leukemia-free survival times revealed significant differences among the three groups (P < 0.0001).

Fas antigen (CD95) in pure erythroid cell line AS-E2 is induced by interferon-gamma and tumor necrosis factor-alpha and potentiates apoptotic death.

We investigated the expression of Fas antigen (CD95) in the pure erythroid cell line AS-E2 in the presence and absence of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). TNF-alpha induced apoptosis in AS-E2 cells, whereas IFN-gamma did not. In culture containing no IFN-gamma or TNF-alpha, AS-E2 cells expressed little Fas antigen. However, IFN-gamma and IFN-gamma and TNF-alpha both induced expression of Fas antigen and its mRNA within 24 hours after the stimulation. When anti-Fas monoclonal antibody (IgM) was added to AS-E2 cells after the induction of Fas expression, AS-E2 cells underwent apoptosis as shown by the induction of DNA fragmentation. This apoptotic change was inhibited by an inhibitor of caspase-3-like proteases (Ac-DEVD-CHO) and an inhibitor of CED-3/ICE family proteases (Z-Asp-CH2-DCB) but not by an inhibitor of caspase-1-like proteases (Ac-YVAD-CHO), suggesting a role for caspase-3-like proteases in Fas-receptor signaling. Although AS-E2 cells expressed Fas ligand mRNA, treatment with ZB4, an antibody that inhibits Fas-mediated cell death, failed to suppress IFN-gamma- or TNF-alpha-mediated cytotoxicity. These findings suggest that the late erythroid progenitor cells are negatively regulated by IFN-gamma and TNF-alpha, both of which are capable of inducing functional Fas expression.

The Wilms' tumor gene WT1 is a good marker for diagnosis of disease progression of myelodysplastic syndromes.

The Wilms' tumor gene, WT1, is a tumor marker for leukemic blast cells. The WT1 expression levels were examined for 57 patients with myelodysplastic syndromes (MDS) (refractory anemia (RA), 35; RA with excess of blasts (RAEB) 14; RAEB in transformation (RAEB-t), six; and MDS with fibrosis, two) and 12 patients with acute myeloid leukemia (AML) evolved from MDS. These levels significantly increased in proportion to the disease progression of MDS from RA to overt AML via RAEB and RAEB-t in both bone marrow (BM) and peripheral blood (PB). WT1 expression levels in PB significantly correlated with the evolution of RAEB or RAEB-t to overt AML within 6 months. Therefore, WT1 expression levels in PB were superior to those in BM for early prediction of the evolution to AML by means of quantitation of the WT1 expression levels. Furthermore, WT1 expression in PB of patients with overt AML evolved from MDS was significantly decreased by effective chemotherapy or allogeneic stem cell transplantation and became undetectable in long-term survivors. These results clearly showed that WT1 expression levels are a tumor marker for preleukemic or leukemic blast cells of MDS and thus reflect the disease progression of MDS. Therefore, monitoring of WT1 expression levels has made continuous assessment of the disease progression of MDS possible, as well as the prediction of the evolution of RAEB or RAEB-t to overt AML within 6 months. The results also showed that quantitation of WT1 expression levels is useful for diagnosis of minimal residual disease of MDS with high sensitivity, thus making it possible to evaluate the efficacy of treatment for MDS.

Paroxysmal nocturnal haemoglobinuria clones in patients with myelodysplastic syndromes.

Among acquired stem cell disorders, pathological links between myelodysplastic syndromes (MDS) and aplastic anaemia (AA), and paroxysmal nocturnal haemoglobinuria (PNH) and AA, have been often described, whereas the relationship between MDS and PNH is still unclear. We analysed blood cells of patients with MDS to determine the incidence of the PNH clone, and analysed the PIG-A gene to find mutations characteristic of the PNH clone in MDS. In four (10%) of 40 patients with MDS, flow cytometry showed affected erythrocytes and granulocytes negative for decay-accelerating factor (DAF) and CD59. The population of affected erythrocytes was smaller in MDS patients with PNH clone (MDS/PNH) than in patients with de novo PNH, and haemolysis was milder in the MDS/PNH patients. PIG-A mutations were found in granulocytes of all patients with MDS/PNH. In type and site, the PIG-A mutations were heterogeneous, similar to that observed in de novo PNH; i.e. no mutation specific to MDS/PNH was identified. Of note, three of four patients with MDS/PNH each had two PNH clones with different PIG-A mutations, suggesting that PIG-A is mutable in patients with MDS/PNH. In a MDS/PNH patient with trisomy 8, FISH detected a distinct karyotype in a portion of granulocytes with PNH phenotype, indicating that PNH and MDS partly shared affected cells. Thus, MDS predisposes to PNH by creating conditions favourable to the genesis of PNH clone. Considering the increasing prevalence and incidence of MDS, these disorders could be useful for investigating the mechanism by which PIG-A mutation is induced.

Human erythropoietin receptor increases GATA-2 and Bcl-xL by a protein kinase C-dependent pathway in human erythropoietin-dependent cell line AS-E2.

Erythropoietin (Epo) is a cytokine known to stimulate proliferation and differentiation of erythroid cells. However, recent gene disruption experiments demonstrated that Epo receptor signaling is not an obligatory step in erythroid differentiation. Here, we describe the role of Epo in proliferation, terminal differentiation, and apoptosis in a novel human Epo-dependent cell line, AS-E2. Upon withdrawal of Epo, the cells ceased to proliferate and underwent apoptotic death. Accompanying this cell death, an increase in the number of hemoglobin-positive cells of approximately 2-fold was observed. This was associated with immediate up-regulation of the GATA-1:GATA-2 ratio and down-regulation of Bcl-xL. Treatment with Epo or 12-O-tetradecanoyl-phorbol-13-acetate (TPA) up-regulated expression of GATA-2 and Bcl-xL, and these elevations were inhibited by inhibitors of protein kinase C (PKC), H7 and H8. HA1004, a structural analogue of H7 but a poor inhibitor of PKC, had no inhibitory effect. Therefore, in AS-E2 cells, it is likely that Epo plays a role in (a) proliferation, (b) inhibition of differentiation, and (c) survival, by maintaining GATA-2 and Bcl-xL expression through activation of PKC.

MRI of posterior knee masses.

A wide variety of masses may be visualized in the posterior knee. Some are encountered incidentally on MRI obtained for seemingly unrelated symptoms; others are palpable and present for MRI characterization. We describe the appearance, significance and pathophysiology of some of the most common lesions found in the popliteal fossa as well as several of the less common entities we have encountered. Thorough understanding of the appearance and location of the more specific masses should augment precise diagnosis in a majority of cases. In turn, this will eliminate unnecessary additional investigations and enable prompt and appropriate treatment.

Meniscal ossicle: radiographic and MR imaging findings.

PURPOSE: To determine the magnetic resonance (MR) imaging appearance of meniscal ossicles and correlate that with the radiographic and clinical features. MATERIALS AND METHODS: Radiographs and MR images were studied retrospectively in six patients with meniscal ossicles; all patients had intermittent discomfort in the knee, and five patients had experienced knee trauma. Imaging findings were correlated with the clinical history. Four patients underwent arthroscopy. RESULTS: All patients had a visible ossicle on conventional radiographs initially interpreted as a loose joint body. MR imaging features included a corticated marrow-containing structure within the substance of the medial meniscus near the tibial attachment that appeared as a rounded focus of increased signal intensity on T1-weighted images that decreased in signal intensity on T2-weighted images. CONCLUSION: Meniscal ossicles have a characteristic MR appearance that may help distinguish them from loose bodies. They should be considered diagnostically when a circumscribed ossification is identified near the posterior horn of the medial meniscus on radiographs.

Clinical evaluation of severe ischemic limbs by tissue reflection spectrophotometry.

The clinical usefulness of tissue reflection spectrophotometry in the prognosis of ischemic limbs was evaluated. The diseased group (n = 12) consisted of 7 cases of femoral artery thrombosis, 4 cases of chronic obstructive arteriosclerosis and 1 case of femoral vein thrombosis. The normal control group consisted of 14 limbs in 7 normal subjects (n = 14). Index of tissue hemoglobin concentration (IHb) was 37.3 +/- 4.5 (n = 14) in the normal control group and 38.5 +/- 16.9 (n = 12) in the diseased group, which was not significantly different. In a subgroup of patients who required amputation or developed necrosis (severe subgroup), the value was 54.2 +/- 1.7 (n = 6). This was significantly higher than the value of 22.8 +/- 8.5 (n = 6) obtained in a subgroup of patients who received the conservative treatment of thrombectomy (mild subgroup) (p < 0.05). Index of tissue oxygen saturation (ISO2) was 28.0 +/- 4.9 (n = 14) in the normal control group, and 9.1 +/- 2.7 (n = 12) in the diseased group (p < 0.05). ISO2 was 7.0 +/- 1.6 (n = 6) in the severe subgroup which was significantly lower than 11.2 +/- 1.9 (n = 6) in the mild subgroup (p < 0.05). Tissue reflection spectrophotometry therefore appears to provide clinically useful information for the prognosis of ischemic limbs.

[A study of organizational communication in a school during the pre- and post-innovation periods].

The purpose of this study was to examine changes in organizational communication behavior in an elementary school during the pre- and post-innovation periods. The turning point of the pre- and post-innovation periods were determined by transference of decision making systems in the school. Data were collected through participant observation, and the analyses indicated the following results. Compared to the pre-innovation period, during the post-innovation period, 1) overall communication level increased; 2) discussions, rational persuasion , and proposals increased, while assertions decreased as the contents of communication; and 3) the number of those who spoke at teaching staff meetings increased. Concerning downward communication, 1) rational persuasive communication was used most frequently throughout the pre- and post-innovation periods; and 2) communication suggesting a compromise increased during the post-innovation period. These findings were discussed in terms of organizational effectiveness of the school.

[Effects of leader behavior on subordinate's upward influence tactics and relationship between subordinate and leader].

This study aimed at examining the upward influence tactics employed by subordinates toward their immediate superiors (the leader) in relation to the cohesiveness of a given group, leadership behavior on the part of the leader, and leadership behavior on the part of the group's top leader. The survey involved a sample of 120 nurses. Each nurse was asked to complete a questionnaire, which was prepared on the basis of an earlier preliminary study. The results of the group survey were as follows: (1) A nurse (the subordinate) generally gave play to the tactics of rationality and enthusiasm vis-a-vis a democratically inclined head nurse (the immediate superior); (2) coalition behavior was widely practiced in groups that were highly cohesive, while higher authority was employed vis-a-vis a democratically inclined top head nurse (the top leader); (3) the above-mentioned actions employing tactics of influence [(1) to (2)] had, in turn, an effect on the degree of response on the part of the head nurse (the leader) and on the ex post factor relationship between the two parties (nurse and head nurse).

[Studies on distribution and excretion of squalane in dogs administered for 2 weeks].

In the previous papers, we demonstrated, by using rats, that squalane (2,6,10,15,19, 23-hexamethyltetracosane) could stimulate the fecal excretion of 2,3,4,7,8-pentachlorodibenzofuran, the most important etiologic agent of Yusho, which was accumulated in the body of rat. We also reported that, in rats and dogs, squalane did not show any appreciable toxic signs during 3-month treatment, though a part of squalane was absorbed from gastrointestinal tract of dogs. In the present paper, we have investigated the elimination of absorbed squalane in beagle dogs. During the treatment with squalane orally at a dose of 1200 mg/kg/day for 14 days, the fecal excretion of squalane per day was 65-90% of the daily dose. After the treatment (on the day 14), squalane levels in blood and hair were about 30 ppm and 14640 ppm, respectively. On the day 56 after the first dosing, squalane was not detected in blood. On the day 70, squalane level in hair was reduced to about 1% of that on the day 14. Squalane levels in skin, liver, adipose tissue and small intestine on the day 70 were also reduced compared with that on the day 42. Moreover, small amount of squalane was still excreted into feces from the day 15 to the day 70. These results suggested that absorbed squalane was gradually excreted through feces and skin in dogs.

[Reproductive and developmental toxicity study of mofezolac (N-22) (3)--Teratogenicity study in rabbits by oral administration].

Mofezolac (N-22) is a new developed analgesic and anti-inflammatory agent. A teratogenicity study of N-22 was carried out in New Zealand White rabbits to examine the effect on the dams and the teratogenic potentiality. N-22 was administered orally at the dose levels of 12.5, 50 and 200 mg/kg during the organogenesis from day 6 to day 18 of gestation. All pregnant females were sacrificed on day 28 of gestation and their fetuses were examined. There were no growth retardation and teratogenic effects on fetuses from the dams administered N-22, although the administration of 200 mg/kg produced a decrease in food consumption of the dams concomitant with the embryocidal effects as shown by an increase in the early resorption rate. Thus, non-toxic dose level of N-22 on the dams and fetuses was considered to be 50 mg/kg.

Anaplastic ependymoma of the spinal cord in childhood. A case report.

We report a 6-year-old girl with anaplastic ependymoma probably originating in the region of the conus medullaris and probably spreading retrogradely to the region of the interventricular foramen (Monro) through the cerebrospinal fluid (CSF). Since ependymoma of the spinal cord rarely occurs in children, and retrograde spreading is extremely rare, the histological features and mechanism of metastasis of the tumor are discussed.

[Effects of the intensity of unstable status structures on the powerholders' power maintaining tendency].

The purpose of the present study was to investigate effects of the intensity of unstable status structures on the powerholders' power maintaining tendency. In advance aptitude test was administered to the subjects (24 male undergraduates). Each subjects was led to believe that he was screened and supervised four performing groups as a powerholder (Top-leader). Each subjects was also assigned to either the status change condition (12 males) or the non status change condition (12 males). The following results were obtained. Compared to the powerholders under the non status change condition, the powerholders under the status change condition (1) evaluated less subleaders' contributions to the high performance group, (2) gave more difficult tasks to the high performance group. These results were compared with the study by this author (1987) and discussed in terms of the relation between the power maintaining tendency and intensity of unstable status structures.