Nonmagnetic Ground State in RuO_{2} Revealed by Muon Spin Rotation.

The magnetic ground state of single crystalline RuO_{2} was investigated by the muon spin rotation and relaxation (µSR) experiment. The spin precession signal due to the spontaneous internal magnetic field B_{loc}, which is expected in the magnetically ordered phase, was not observed in the temperature range 5-400 K. Muon sites were evaluated by first-principles calculations using dilute hydrogen simulating muon as pseudohydrogen, and B_{loc} was simulated for the antiferromagnetic structures with a Ru magnetic moment |m_{Ru}|≈0.05µ_{B} suggested from diffraction experiments. As a result, the possibility was ruled out that muons are localized at sites where B_{loc} accidentally cancels. Conversely, assuming that the slow relaxation observed in µSR spectra was part of the precession signal, the upper limit for the magnitude of |m_{Ru}| was estimated to be 4.8(2)×10^{-4}µ_{B}, which is significantly less than 0.05µ_{B}. These results indicate that the antiferromagnetic order, as reported, is unlikely to exist in the bulk crystal.

Precise spectroscopy of 167Er:Y2SiO5 based on laser frequency stabilization using a fiber laser comb.

Precise spectroscopy of the hyperfine level system of 167Er-doped Y2SiO5 was achieved in the frequency domain. By using an optical frequency comb to stabilize the light source frequency to an accuracy on the order of hertz on a long-term scale, Allan deviation < 10 Hz was achieved for an integration time of 180 s. As a result, spectral hole-burning experiments yielded a more accurate hole spectrum with a narrow homogeneous linewidth. The method opens the way to the straightforward exploration of relaxation mechanisms in the frequency domain by simple steady-state measurements.

Activities of thymidylate synthetase and thymidine kinase in gastric cancer.

In a previous clinical study, sequential methotrexate and 5-fluorouracil has shown improved efficacy for treating advanced gastric cancer of the poorly differentiated type. In this study, we investigated whether difference in the levels of thymidylate synthetase (TS) and thymidine kinase (TK) activities in gastric cancer tissue account for selectivity of the treatment. Activity of TS was higher in 19 cases of the poorly differentiated type than in 16 cases of the well differentiated type (P < 0.02), whereas TK activity was lower in the poorly differentiated type than in the well differentiated type (P < 0.01). Thus, the TS/TK ratio was significantly higher in poorly differentiated gastric cancers than in well differentiated cancers (P < 0.001). These results suggest that a greater dependence upon the de novo pathway of pyrimidine synthesis in poorly differentiated gastric carcinomas may enhance the efficacy of sequential methotrexate and 5-fluorouracil treatment.

Therapeutic efficacy and toxicity of sequential methotrexate and 5-fluorouracil in gastric cancer.

The therapeutic efficacy and toxicity of sequential methotrexate and 5-fluorouracil in 64 inoperable gastric cancer patients are reported. An intermediate-dose treatment was given to 48 patients, and a low-dose treatment to 16 patients. In the intermediate-dose treatment, leukopenia was observed in 11 patients, nausea and vomiting in six patients and diarrhea and stomatitis in two patients each. In the low-dose treatment, no patient developed toxic symptoms of grade 3 or 4. All 9 responders had adenocarcinoma of the poorly differentiated type and the response rate in patients who belonged to this type was 32.1%.

Mastoid pneumatization in children with congenital cholesteatoma: an aspect of the formation of open-type and closed-type cholesteatoma.

OBJECTIVES: To clarify mastoid pneumatization in children with congenital cholesteatoma and compare their clinical characteristics. STUDY DESIGN: The mastoid pneumatization of 34 children with congenital middle ear cholesteatoma, of 34 age-matched children with unilateral acquired cholesteatoma, and of 17 age-matched control children without middle ear diseases was studied. METHODS: The sizes of the mastoid cells were measured from 1.5-mm sliced semiaxial sections of a temporal bone computed tomography scan. The sum of the two areas from the two images, one showing the lateral semicircular canal and the other, 3 mm below this, was defined as the area of the pneumatized mastoid cells. RESULTS: The mastoid cells in ears of children with congenital cholesteatoma were poorly pneumatized compared with those of control children without middle ear diseases, but were better pneumatized compared with those of children with acquired cholesteatoma. In children with congenital cholesteatoma, the degree of pneumatization in the cholesteatoma side was significantly poorer than that in the opposite side. A well-pneumatized mastoid was seen in ears with no episode of otitis media, in ears with the open-type cholesteatoma, and in ears with ossicular anomalies. CONCLUSIONS: The presence of cholesteatoma matrix accelerates the inflammatory response when middle ear infections occur, and this probably leads to the suppression of mastoid pneumatization. The authors also propose the hypothesis that cholesteatoma in most congenital cases is the open type, and that middle ear inflammation may contribute to the formation of cystic and closed-type cholesteatoma.

Pressure-jump apparatus suitable for repetitive experiments.

A repetitive pressure-jump apparatus has been devised and used for the measurement of a small relaxation effect in solution. Although the pressure rise time of the apparatus is inferior to the usual method, signal averaging has enhanced signal-to-noise ratio of the relaxation spectrum.

Portal tumor thrombi due to gastric cancer.

A patient with a primary gastric carcinoma complicated with a tumor thrombus in the portal vein is described. Pancreatoduodenectomy with tube pancreatostomy was performed. The location and size of tumor thrombi in the portal vein could be determined accurately by intraoperative ultrasonography and removed with the wall of the portal vein and superior mesenteric vein. There was no evidence of recurrence one year after the operation. Tumor thrombus in the portal vein in gastric cancer is rarely reported and has a poor prognosis. If there is no associated liver metastasis, aggressive surgical approach followed by appropriate chemotherapy may prolong the life of the patient.

Hepatoid adenocarcinoma of the stomach: a case report.

A patient with primary gastric carcinoma showing a high level of serum a-fetoprotein (AFP) (368 ng/ml) is described. Subtotal gastrectomy was performed, and a month after surgery the level of serum AFP fell rapidly to within normal limits. Histologically, two types of cells coexisted in the tumor: medullary-type cells resembling trabecular-type hepatocellular carcinoma, and moderately differentiated adenocarcinoma cells. The cells of the former type were arranged mostly in a trabecular pattern with bile granules, but also showed a scirrhous pattern in a restricted area. Immunohistochemistry demonstrated that both types of tumor cells stained positively for AFP. This tumor, which should be classified as a hepatoid adenocarcinoma of the stomach, is of interest because of its rarity, bile secretion (indicating marked differentiation toward a hepatocyte form), and two cellular arrangements-trabecular and scirrhous.

Plasma collection using nafamostat mesilate and dipyridamole as an anticoagulant.

Nafamostat mesilate (FUT-175) is a strong protease inhibitor and is used as an anticoagulant in extracorporeal circulation. In the present study, we administered FUT and dipyridamole as anticoagulants during donor plasmapheresis, and the additional effect of dipyridamole was examined. In dogs weighing about 15 Kg, donor plasmapheresis was performed using a cellulose triacetate membrane plasmaseparator (PEX-15, Nipro), and 300 ml of filtrated plasma was obtained within 30 minutes. These dogs were divided into two groups, 50 mg/h of FUT alone was infused (group A, n = 10), and the same dose of FUT and 25 mg/h of dipyridamole were infused (group B, n = 5) during plasmapheresis. Changes of the coagulation system, blood cell counts and complement system were investigated. In clinical cases, an artificial liver support therapy using FUT as an anticoagulant was performed on 8 patients with acute liver failure, and blood compatibility was examined. In dogs, RBC counts and hematocrits were almost stable, but WBC counts were decreased to about 70% of the previous value. Platelets counts were about 60% and 80% of the previous value, in group A and group B, respectively, at the end of the plasmapheresis (P less than 0.01). Clotting factor VII was diminished to about 20% and 35% of the previous value in group A and B, respectively. In clinical cases, all patients received the plasma exchange combined with hemodialysis using FUT as an anticoagulant, and no distinct side effect was observed during plasma exchange.

Effect of oral adsorbent on blood metabolites in hepatic failure dogs.

AST-120 is a specially synthesized carbonaceous adsorbent for oral use. It mainly adsorbs low to middle molecules in the alimentary tract. In the present study, AST-120 was administered to hepatic failure dogs, and blood metabolites were analyzed by high performance liquid chromatography (HPLC). Thirty adult mongrel dogs underwent posta-cavae (P-C) shunts with 40% and 70% hepatectomies. They were divided into two groups, the AST group (n = 19) and control group (n = 11). The AST group received about 0.5 g/kg of the adsorbent intermittently with diet after the operation. The control group was fed the ordinary diet. Body weight, blood ammonia, plasma bile acids were measured, and blood metabolites were analyzed by the multi-column HPLC system. P-C shunt dogs with 70% hepatotectomies died within three months showing about 40-50% body weight loss. HPLC analysis of their plasma showed some specific peaks for middle molecules, about 3000-5000 daltons. After administration of the adsorbent, these peaks were not detected, so it was considered that these substances had been adsorbed.

[Clinical evaluation of sequential MTX/5-FU therapy for gastric cancer].

Sequential MTX/5-FU therapy was performed on 64 patients with unresectable or recurrent gastric cancer. The therapy was most effective in patients with poorly differentiated type gastric cancer. We adopted the intermediate (MTX: 100mg/m2, 5-FU: 800mg/m2) and low (MTX: 30mg/m2, 5-FU: 600 mg/m2) dose regimens. The latter was performed at the outpatient clinic every 2 weeks. This therapy was used for patients with Borrmann type 4 gastric cancer or advanced gastric cancer of poorly differentiated type as postoperative adjuvant chemotherapy. The response rate was 25% in 44 evaluable patients, and 33% in patients with poorly differentiated type cancer. As an adverse effect, leukopenia (grade 3, 4) was observed in 4 patients (9%). The 5-year cumulative survival rate of the sequential MTX/5-FU therapy group (52.6%) was much better than the conventional adjuvant chemotherapy group (32.1%) in patients who underwent curative resection with Borrmann type 4 gastric cancer. One patient survived more than 900 days after non-curative resection with peritoneal dissemination (P 3) after low dose therapy of sequential MTX/5-FU. For the patients who did not respond to the MTX/5-FU therapy, MTX/CDDP/LV/5-FU therapy was adopted. This protocol consisted of MTX (30 mg/m2 iv; day 1), CDDP (60 mg/m2 div; day 2 and day 9), Leucovorin (30 mg iv; day 2-9) and 5-FU (250 mg/m2 div; day 2-9). We also performed MTX/CDDP/LV/5-FU therapy for the treatment of differentiated type gastric cancer.

[Mechanism of synergism and clinical results of sequential methotrexate and 5-fluorouracil in the treatment of gastric cancer].

Mechanism of synergism and clinical results of methotrexate and 5-fluorouracil (MTX/5-FU) combination therapy for gastric cancer were studied. The response rate against poorly differentiated gastric cancers was 35% in this treatment. This treatment also showed a remarkable effect against cases with pleural and abdominal effusion caused by cancerous disseminations. A promising result was obtained by this treatment as neoadjuvant and postoperative chemotherapy against Borrmann type 4 gastric cancer. A greater dependence on the de novo pathway of pyrimidine synthesis against poorly differentiated gastric carcinoma, which was estimated by the fact that the thymidylate synthetase/thymidine kinase ratio was significantly higher in poorly differentiated gastric cancer than in well differentiated cancer, may potentiate therapeutic results of this treatment.

[Adjuvant chemotherapy with UFT or UFT with OK-432 to patients with gastric and colorectal cancer. Kanto Adjuvant Study Group].

In Japan, long-term oral therapy with tegafur in combination with immunopotentiators is commonly used as adjuvant therapy after curative resection of gastric or colorectal can for gastric and colorectal cancer. When the outcome was analyzed in terms of the relative performance (R.P.) and the individual dose intensity (I.D.I.) of OK-432, gastric cancer patients with a R.P. of 0.5 or higher tended to have a better survival curve. There were no marked differences in lymphocytes subsets, except that the Leu 7 level at 3 months after gastric cancer resection was significantly higher (p < 0.05) in group B than in group A. Thus, no inhibition of the anticancer effect of UFT was noted during long term combination therapy with UFT and an immunopotentiator as postoperative adjuvant therapy for patients who underwent curative resection of gastric or colorectal cancer. The results suggest that UFT combined with long-term OK-432 maintenance therapy may contribute to improve survival rates in gastric cancer patients.

[Effect of sequential MTX/5-FU therapy for a case of disseminated intravascular coagulation syndrome associated with recurrence of gastric cancer--a case report].

Although a 39-year-old male received the curative operation of total gastrectomy for advanced scirrhous carcinoma of the stomach, recurrence of cancer was occurred soon after the surgery, accompanied by hemorrhagic diathesis from DIC. The abdominal CT scan examination revealed the rapid enlargement in the size of the several lymphnodes around the abdominal aorta, and the blood chemistry tests showed marked increase of the serum CEA value. The sequential chemotherapy with intermediate dose of MTX and 5-FU in conjunction with OK-432 was started to treat the case. This chemotherapy was carried out once a week for 5 times and consequently DIC was led to the perfect remission. Furthermore, CEA level decreased within normal range, and the size of the enlarged lymphnodes at paraaortic area diminished remarkably. Although he complained of nausea and loss of appetite during the treatment, no severe adverse effects such as granulocytopenia, diarrhea, or loss of hair were observed. The successful result in this patient suggests that sequential therapy of intermediate dose of MTX and 5-FU with administration of OK-432 may be effective in the treatment of advanced scirrhous carcinoma of the stomach.

[A case of alpha-fetoprotein-producing gastric carcinoma with unique macroscopical configuration].

A gastric carcinoma with unique macroscopical configuration was resected from a 63-year-old male patient. Serum level of alpha-fetoprotein (AFP) was markedly elevated (19,000 ng/ml), and AFP-positive cells were found in the carcinomatous tissues. The cytoplasm of the carcinoma cells appeared to be watery-clear by light microscopy, however, electron microscopy revealed abundant amorphous substances in their cytoplasmic matrix. The unique macroscopical configuration of the gastric carcinoma may reflect its biological resemblance to hepatocellular carcinoma. Such a case may be rare, but AFP production, per se, seems to be a rather universal phenomenon of gastric carcinomas.

Insular superconductivity in a Co-doped iron pnictide CaFe1-xCoxAsF.

The presence of a macroscopic phase separation between the superconducting and magnetic phases in CaFe1-xCoxAsF is demonstrated by muon spin rotation measurements conducted across their phase boundaries (x=0.05-0.15). The magnetic phase tends to retain the high transition temperature (Tm>Tc), while Co doping induces strong randomness. The volumetric fraction of the superconducting phase is nearly proportional to the Co content x with a constant superfluid density. These observations suggest the formation of superconducting "islands" (or domains) associated with Co ions in the Fe2As2 layers, indicating a very short coherence length.

Multigap superconductivity in sesquicarbides La2C3 and Y2C3.

A complex structure of the superconducting order parameter in Ln2C3 (Ln=La,Y) is demonstrated by muon spin relaxation measurements in their mixed state. The muon depolarization rate sigma v(T)] exhibits a characteristic temperature dependence that can be perfectly described by a phenomenological double-gap model for nodeless superconductivity. While the magnitude of two gaps is similar between La2C3 and Y2C3, a significant difference in the interband coupling between those two cases is clearly observed in the behavior of sigma v(T).

The effect of oral adsorbent on surgically induced hepatic failure.

The oral adsorbent AST-120 is one type of activated carbon for oral use. In the present study, AST-120 was administered, to clarify its effect, on surgically induced hepatic failure in dogs and rats. Portacaval shunts and varying extents of hepatectomies were performed on 44 dogs. Eleven dogs were given an ordinary diet (control group), and 33 dogs received the oral adsorbent with an ordinary diet after the operation (AST group). Plasma bile acids and ammonia increased, and body weight decreased in both groups. However, after the administration of AST-120, the plasma bile acids and ammonia decreased significantly, and the body weight tended to increase in the AST group. Portacaval shunts and about 70 per cent hepatectomy were performed on 59 Sprague-Dawley rats. These rats were divided into two groups, diet with the oral adsorbent (AST group, n = 19) and an ordinary diet alone (control group, n = 40). DNA synthesis and protein synthesis of the liver were measured on the 5th, 10th and 20th postoperative days using radioisotopes in these rats. Both DNA and protein synthesis of the liver were increased significantly in the AST group. Histological examination revealed many more glycogen granules in the cytoplasm of hepatocytes in the AST group compared to the control group on the 5th postoperative day. It was suggested that some metabolic toxin was adsorbed by AST-120 in the alimentary tract.