Two-Dimensional Superconductor with a Giant Rashba Effect: One-Atom-Layer Tl-Pb Compound on Si(111).

A one-atom-layer compound made of one monolayer of Tl and one-third monolayer of Pb on a Si(111) surface having √3×√3 periodicity was found to exhibit a giant Rashba-type spin splitting of metallic surface-state bands together with two-dimensional superconducting transport properties. Temperature-dependent angle-resolved photoelectron spectroscopy revealed an enhanced electron-phonon coupling for one of the spin-split bands. In situ micro-four-point-probe conductivity measurements with and without magnetic field demonstrated that the (Tl, Pb)/Si(111) system transformed into the superconducting state at 2.25 K, followed by the Berezinskii-Kosterlitz-Thouless mechanism. The 2D Tl-Pb compound on Si(111) is believed to be the prototypical object for prospective studies of intriguing properties of the superconducting 2D system with lifted spin degeneracy, bearing in mind that its composition, atomic and electron band structures, and spin texture are already well established.

High-yield synthesis of conductive carbon nanotube tips for multiprobe scanning tunneling microscope.

We have established a fabrication process for conductive carbon nanotube (CNT) tips for multiprobe scanning tunneling microscope (STM) with high yield. This was achieved, first, by attaching a CNT at the apex of a supporting W tip by a dielectrophoresis method, second, by reinforcing the adhesion between the CNT and the W tip by electron beam deposition of hydrocarbon and subsequent heating, and finally by wholly coating it with a thin metal layer by pulsed laser deposition. More than 90% of the CNT tips survived after long-distance transportation in air, indicating the practical durability of the CNT tips. The shape of the CNT tip did not change even after making contact with another metal tip more than 100 times repeatedly, which evidenced its mechanical robustness. We exploited the CNT tips for the electronic transport measurement by a four-terminal method in a multiprobe STM, in which the PtIr-coated CNT portion of the tip exhibited diffusive transport with a low resistivity of 1.8 kOmega/microm. The contact resistance at the junction between the CNT and the supporting W tip was estimated to be less than 0.7 kOmega. We confirmed that the PtIr thin layer remained at the CNT-W junction portion after excess current passed through, although the PtIr layer was peeled off on the CNT to aggregate into particles, which was likely due to electromigration or a thermally activated diffusion process. These results indicate that the CNT tips fabricated by our recipe possess high reliability and reproducibility sufficient for multiprobe STM measurements.

[Intestinal permeability in Crohn's disease and effects of elemental dietary therapy].

Enteral intake of non-metabolic monosacharide and disaccharide, followed by measurement of the urinary excretion ratio of the two, is a method used to investigate intestinal permeability. L/R ratio (lactulose/1-rhamnose urinary excretion ratio) is considered an indicator of permeability of the small intestine. An increased L/R ratio is caused by mucosal disorders of the small intestine. The L/R ratio in all patients (n = 92) with Crohn's disease was 0.079 +/- 0.081 (mean +/- S.D.), which was significantly higher than the value in normal controls (0.027 +/- 0.009, n = 20, p < 0.05). In 39 patients with Crohn's disease, we assessed intestinal permeability before after treatment with an elemental diet, and during remission. The L/R ratio was 0.120 +/- 0.092, before treatment and 0.065 +/- 0.097 after treatment (p < 0.05), showing increased intestinal permeability before elemental dietary treatment. During remission, the L/R ratio was 0.035 +/- 0.028; this did not differ significantly from the value obtained after treatment. We conclude that intestinal permeability is useful for investigating disease activity in patients with Crohn's disease.

Efficacy of treatment with chimeric monoclonal antibody (Infliximab) to tumor necrosis factor-alpha for Crohn's disease in Japan: evaluation by rapid turnover proteins, and radiologic and endoscopic findings.

BACKGROUND: Several studies have reported that the chimeric monoclonal antibody to tumor necrosis factor (TNF)-alpha (Infliximab) is extremely valuable in the treatment of Crohn's disease. The aim of this study was to clarify the efficacy of this treatment in Japanese patients with Crohn's disease. METHODS: A 12-week multicenter, open trial of Infliximab was carried out and involved 25 patients with moderate to severe Crohn's disease who were resistant to conventional treatment. Patients received a single 2-h intravenous infusion of Infliximab at a dose of 1, 3, 5 or 10 mg/kg bodyweight. Clinical evaluation of this treatment response was defined as a reduction in the index of the inflammatory bowel disease (IOIBD) and of the Crohn's disease activity index scores (CDAI), and in serum levels of C-reactive protein (CRP) at 2, 4, 8 and 12 weeks, and as an increase in serum levels of rapid turnover proteins as well as improvement of radiologic and endoscopic findings at 4 weeks. RESULTS: The IOIBD score was reduced after 4 weeks in 66.7% of the group receiving 1 mg/kg Infliximab, 71.4% in the group receiving 3 mg/kg, 80.0% in the group receiving 5 mg/kg, and 85.7% in the group receiving 10 mg/kg. Improvement was better maintained over 12 weeks in the 5 and 10 mg/kg groups compared with the 1 and 3 mg/kg groups. Similar results were obtained for the CDAI scores. Serum levels of rapid turnover proteins significantly increased to within the normal ranges after infusion in all groups. Seven of the 11 (63.6%) patients evaluated showed improvement of radiologic and endoscopic findings. CONCLUSIONS: A single infusion of Infliximab was effective for the treatment of Japanese patients with Crohn's disease. Serum rapid turnover proteins reflected the clinical response to antibody for TNF-alpha well.

Investigation of the association between infection with Helicobacter pylori and with TT virus, a novel DNA virus, in patients with gastroduodenal ulcer or ulcer scar.

OBJECTIVE: Recently, a novel DNA virus (TT virus; TTV) has been isolated. Enteric transmission is suggested as a route of transmission of TTV, with high prevalence of this virus infection in the general population, and age and geographical distributions of TTV prevalence very similar to those of Helicobacterpylori infection. We analysed an association between TTV and H. pylori infection in patients with gastroduodenal ulcer or ulcer scar. METHODS: In 181 patients with a gastroduodenal ulcer or ulcer scar (102 with a gastric lesion, 60 with a duodenal lesion, and 19 with both sites involved), specimens were cultured for H. pylori and TTV infection was sought in serum by a polymerase chain reaction. RESULTS: H. pylori infection was demonstrated in 152 patients (84.0%) and TTV was detected in 168 patients (92.8%). Patients with TTV were significantly older than those without TTV (P = 0.0001), while no age difference was observed between patients with and without H. pylori infection. No difference was apparent in the prevalence of TTV infection between patients with and without H. pylori infection, and vice versa. CONCLUSIONS: We found no association between TTV infection and H. pylori infection in patients with peptic ulcer diseases, which is consistent with a lack of association between TTV infection and peptic ulcer. However, larger studies including surveys of the general population will be required to analyse the overall association between TTV and H. pylori.

[Unusual form of ulcerative colitis].

Segmental colitis which showed the similar findings of ulcerative colitis and right-sided colitis with back-wash ileitis has been considered as the unusual form of ulcerative colitis. Today, we have few opportunities to come across those cases, because modern diagnosis of colon disease could make differential diagnosis easily with the sense of broad spectrum of IBD. We presented three cases of segmental colitis and one case of so-called indeterminate colitis associated of carcinoma in the cecum and discussed the clinical significance for diagnosis and finding the step of studying the etiology of IBD. Especially, in the third case, thirteen years old man was showing the sign of early stage of Crohn disease with non-caseating granuloma in the biopsy specimen at first, the findings of the segmental ulcerative colitis with crypt abscess were seen after six months in the second examination. To observe the detail changes of the mucosal lesion in this kind of cases will present the new idea for studying the etiology of IBD.

[Treatment of advanced gastric and colorectal cancer with 5-FU, leucovorin and interferon-alpha].

Twenty-four patients with advanced or relapsed gastric or colorectal cancer were treated with a combination of 5-fluorouracil (5-FU), leucovorin (LV) and interferon-alpha (IFN-alpha). 5-FU was administered by rapid intravenous infusion at 350 mg/m2 for 5 consecutive days. Intravenous bolus administration of LV 20 mg/m2 was given before each 5-FU administration. This combination was repeated every 3 to 4 weeks. IFN-alpha (HLBI), 6MU, was administered subcutaneously daily. Of 13 patients with gastric cancer, there were 2 PR, 4 NC and 7 PD, and among 11 patients with colorectal cancer, there were 1 CR, 8 NC and 2 PD. All 16 previously treated patients had no clinical response. Responses were seen in patients with no prior chemotherapy and with good performance status. Most common toxicities observed were leucopenia, fever, stomatitis and diarrhea, which were all tolerable and reversible.

Effect of thiamine and thiamine levels on experimental alloxan induced diabetes mellitus.

The effects of thiamine (T) on diabetes mellitus (DM) and the T levels in the brain, heart, liver, kidneys pancreas, muscle, adipose tissue and blood were measured. For the experimental DM model, alloxan (170 mg/kg, i.v.) was injected into male ddY mice and insulin was also administered for 5 days to prevent death by hyperglycemia (DM group). After 14 days, blood glucose level increased to 455 mg/dl, compared to 166 mg/dl in the normal control group (NC group). In the DM mice, the T level in the liver decreased to 7.71 micrograms/g, compared to 16.29 micrograms/g in the NC group. The T levels in the heart, pancreas, muscle and adipose tissue increased to 18.63 micrograms/g, 3.99 micrograms/g, 2.53 micrograms/g and 5.07 micrograms/g in the DM group, compared to 14.99 micrograms/g, 3.27 micrograms/g, 1.98 micrograms/g and 4.04 micrograms/g in the NC group, respectively. The T levels in the brain and kidney were 2.38 micrograms/g and 14.00 micrograms/g in the DM group, compared to 2.34 micrograms/g and 13.72 micrograms/g in the NC group, respectively. But, in the heart, an active form of a T co-enzyme decreased to 27%, compared to 95% for the NC group. These results indicate a T deficiency or an endogenous T deficiency in the DM group. All DM mice without insulin treatment died within 7 days but about 40% of the mice survived up to 14 days with the administration of T.

[Effect of oxythiamine and pyrithiamine on thiamine levels in the blood, liver and urine of rats (author's transl)].

Thiamine (T) deficient state and various functional and morphological changes in rat liver were induced, after several days, with T antagonists, oxythiamine (OT) or pyrithiamine (PT), and a thiamine deficient diet (TDD). The relationship between the extent of liver damage and T levels in blood, liver and urine were studied in OT treated rats fed a TDD (OTD group). PT treated rats fed a TDD (PTD group), OT treated rats (OT group), PT treated rats (PT group) and rats fed a TDD (TDD group). The T levels in blood and liver of OT group, PT group, OTD group, PTD group and TDD group were 89% and 91%, 76% and 88%, 25% and 14%, 33% and 16%, 24% and 15% compared with the data in the control group, respectively. Effects of OT or PT on T levels were not remarkable in some cases, and such may be due to the duration time of T antagonists, which was considered to be 3-15 hours in PT treated rats, and 0-18 hours in PT treated rats, as assessed by urinary T measurements. Treatment of T antagonist twice daily is recommended to obtain a definite T deficient state. Our results suggest that the extent of liver damage is related to the T levels in tissue.

Erythrocytosis in thiamine deficient rats.

A thiamine (T) deficient state in rats was produced by feeding the rats a T deficient diet (TDD). At the stage of 13 days (TDD13 group), the number of red blood cells (RBC) and white blood cells (WBC), hematocrit (Ht) and hemoglobin (Hb) values decreased. On the other hand, after 30 days on the TDD (TDD30 group), the number of RBC was 819 x 10(4)/mm3 as against 631 x 10(4)/mm3 in the normal control group (NC group). Ht and Hb values also increased in the TDD30 group. These changes observed in the TDD30 group were significantly different from findings in the equal weight control group (EWC group) or in the pair fed control group (PFC group). The number of reticulocytes increased, the levels of 2,3-diphosphoglycerate (2,3-DPG) of RBC decreased and plasma erythropoietin levels increased in the TDD30 group. T levels of blood in the TDD13 group were 62 (39-79) ng/ml as against 275 (196-412) ng/ml in the NC group. T levels of blood in the TDD30 group were 102 (17-365) ng/ml, and widely varied. Decrease in 2,3-DPG produces an increase in O2 affinity to Hb, and hypoxia is induced in the peripheral tissues. Furthermore these conditions stimulate erythropoietin production and finally the number of RBC increases. T deficiency produces anemia at an early stage and absolute erythrocytosis occurs at the late stage of T deficiency. The increased osmotic resistance of RBC in hypotonic solution was also observed in the TDD30 group. This increase in osmotic resistance correlated with the decrease in cholesterol and phospholipid levels in the membrane of RBC.

[Effect of pyrithiamine on rat sciatic nerve. (I) Morphological changes during the early stage of thiamine deficiency (author's transl)].

We observed under light and electron microscopes morphological changes in the rat sciatic nerve during the early stages of a thiamine deficient state as induced by a pyrithiamine (PT: 50 microgram/100g X 6 days) and thiamine deficient diet (TDD). We simultaneously determined thiamine levels in the whole sciatic nerve of rats. Experiments were undertaken with normal control, TDD (rats fed a TDD), PT (PT treated rats) and PTD (PT treated rats fed a TDD) groups. Microscopically, there were numerous shrunken myelinated axons with myelin ovoids of folds in the PT group and many swollen ones in the PTD group. Electron microscopically, we found more advanced lesions in the PTD group than in the other groups. These ultrastructural changes were swelling of Schwann cells, enlarged rough-surfaced endoplasmic reticulum, axonal degeneration with shrinkage, loss of organelle or abnormal myelin sheath, and proliferation of fibroblasts. The thiamine level in the PTD group decreased to 18 approximately 30% that of control in proportion to the morphological changes. On the other hand, the thiamine level in the PT group (55 approximately 61%) decreased slightly more than that of the TDD group (50 approximately 56%), but changes in morphology were vice versa. These results suggest that the morphological changes in the sciatic nerve caused by PT-induced thiamine deficiency differs from changes seen in cases of dying-back neuropathy caused by TDD-induced deficiency, and that PT itself directly affects the nervous system

[Effect of oxythiamine and pyrithiamine on rat brain--morphological changes in the thiamine deficient rat brain (author's transl)].

We observed under light and electron microscopes morphological changes in the brains of rats in a thiamine deficient state as induced by an oxythiamine, pyrithiamine and thiamine deficient diet (OT, PT and TDD). We simultaneously determined thiamine levels in the whole brain of rats. The rats were separated into six groups-normal control, OT or PT treated rats (OT or PT group), OT or PT treated rats fed a TDD (OTD or PTD group), rats fed a TDD (TDD group)-. Microscopically, there were symmetrically distributed lesions containing spongy reticulation mainly in the vestibular nucleus. Electron microscopically, we found more advanced lesions in the OTD and PTD groups than in the TDD group. These ultrastructural changes were seen in the vicinity of capillaries and such consisted of abnormal endothelial cells and pericytes, excrescence of microglias, swelling or vacuolation of astrocytes, nerve cells containing distorted organelle and myelin degeneration, besides extracellular edema. The thiamine level in the TDD group decreased to 56% that of control. No effect of OT on the thiamine level was observed either in case of ingestion of a regular diet or when TDD was given. On the other hand, the thiamine level decreased to 43% in the PT group and to 17-23 in PTD. These results suggest that encephalopathy caused by the OT or PT-induced thiamine deficiency has the same selective vulnerable site as does the TDD-induced deficiency, however cellular sensitivity may differ slightly with the various ultrastructural changes.