Growth of bulk ß-Ga2O3 crystals from melt without precious-metal crucible by pulling from a cold container.

We report the growth of bulk ß-Ga2O3 crystals based on crystal pulling from a melt using a cold container without employing a precious-metal crucible. Our approach, named oxide crystal growth from cold crucible (OCCC), is a fusion between the skull-melting and Czochralski methods. The absence of an expensive precious-metal crucible makes this a cost-effective crystal growth method, which is a critical factor in the semiconductor industry. An original construction 0.4-0.5 MHz SiC MOSFET transistor generator with power up to 35 kW was used to successfully grow bulk ß-Ga2O3 crystals with diameters up to 46 mm. Also, an original diameter control system by generator frequency change was applied. In this preliminary study, the full width at half maximum of the X-ray rocking curve from the obtained ß-Ga2O3 crystals with diameters ≤ 46 mm was comparable to those of ß-Ga2O3 produced by edge-defined film fed growth. Moreover, as expected, the purity of the obtained crystals was high because only raw material-derived impurities were detected, and contamination from the process, such as insulation and noble metals, was below the detection limit. Our results indicate that the OCCC technique can be used to produce high-purity bulk ß-Ga2O3 single crystalline substrate.

Effectiveness of patient and staff cohorting to reduce the risk of vancomycin-resistant enterococcus (VRE) acquisition: a retrospective cohort study during a VRE outbreak in Japan.

BACKGROUND: Patient and staff cohorting is part of a bundle approach in the response to multi-drug-resistant organisms, but its effectiveness is not fully clarified. This study compared the risks of acquiring vancomycin-resistant Enterococcus faecium (VREfm) at a hospital during a VREfm outbreak based on contact characteristics in order to better understand the effectiveness of cohorting. METHODS: Exposure came from contact with patients with VREfm (infectors), including existing patients with VREfm and patients who acquired VREfm during the study period. Contact was defined as length of contact time, degree of sharing space, and care by the same nurses as those caring for infectors between January and March 2018. The outcome was VREfm acquisition as determined through monthly stool or rectal screening cultures. Incidence rates were calculated based on contact patterns, and incidence rate ratios (IRRs) were compared. FINDINGS: Among 272 inpatients (4038 patient-days), 43 patients acquired VREfm with the same or similar pulsotype. Incidence rates were 8.45 per 1000 patient-days when susceptible inpatients were on the same ward as an infector but cared for by different nurses (reference), 16.96 when susceptible inpatients were on the same ward as an infector and cared for by the same nurses [IRR 2.01, 95% confidence interval (CI) 0.62-10.28], and 52.91 when susceptible inpatients shared a room with an infector (IRR 6.26, 95% CI 1.61-35.40). CONCLUSION: Compared with susceptible inpatients in a different room from infectors and not being cared for by the same nurses, the risk of VREfm acquisition could be six times higher for susceptible inpatients who are in the same room as infectors, and could be double for susceptible inpatients cared for by the same nurses as infectors.

JTT-130, a novel intestine-specific inhibitor of microsomal triglyceride transfer protein, ameliorates impaired glucose and lipid metabolism in Zucker diabetic fatty rats.

AIM: Microsomal triglyceride transfer protein (MTP) takes part in the mobilization of triglyceride-rich lipoproteins from enterocytes and hepatocytes. We investigated the effects of JTT-130, a novel intestine-specific MTP inhibitor, on impaired glucose and lipid metabolism in Zucker diabetic fatty (ZDF) rats. METHODS: Male ZDF rats were fed a regular powdered diet with or without JTT-130 as a food admixture (0.01-0.02%) for 6 weeks. Food intake, body weight, blood biochemical parameters, fecal lipid contents, hepatic lipid contents, tissue mRNA levels and glucose utilization in adipose tissues were assessed. An intraperitoneal glucose tolerance test (IPGTT) and histological analysis of the pancreas were performed. RESULTS: JTT-130 treatment decreased food intake, glycated hemoglobin, plasma levels of glucose, triglycerides and total cholesterol, hepatic levels of triglycerides and cholesterol and hepatic mRNA levels of glucose-6-phosphatase, phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase. JTT-130 treatment increased fecal levels of free fatty acids and cholesterol, plasma levels of glucagon-like peptide-1 and peptide YY, mRNA levels of glucose transporter 4 (GLUT4) and lipoprotein lipase in adipose tissues and GLUT4 in muscle and glucose utilization in adipose tissues. Plasma insulin decreased after 2 weeks and increased after 4 weeks of JTT-130 treatment. Plasma glucose in the JTT-130-treated rats was lower with higher plasma insulin than in the control rats during the IPGTT. The islets of the JTT-130-treated rats were larger and contained more insulin than those of the control rats. CONCLUSIONS: JTT-130 ameliorates impaired glucose and lipid metabolism in the ZDF rats thereby suggesting that JTT-130 could be useful for prevention and treatment of type 2 diabetes.

Expression of a transgenic T cell receptor beta chain enhances collagen-induced arthritis.

SWR/J transgenic (tg) mice were generated expressing the TCR beta chain derived from an anticollagen type II (CII) arthritogenic T cell clone. The SWR/J strain was selected because it is resistant to collagen-induced arthritis (CIA) and lacks the V beta gene segment used by the T cell clone. Expression of the tg beta chain on all thymocytes and peripheral lymph node T cells led to a more efficient anti-CII immune response, but did not confer CIA susceptibility to SWR/J mice. Nevertheless, this tg beta chain enhanced predisposition to CIA as (DBA/1 x SWR) F1 beta tg mice were more susceptible than normal F1 littermates. Our results demonstrate that the expression of the tg beta chain contributes to CIA susceptibility, but by itself it is not sufficient to overcome CIA resistance in the SWR/J strain.

Cot/Tpl2 regulates IL-23 p19 expression in LPS-stimulated macrophages through ERK activation.

We have previously reported that a serine/threonine protein kinase, Cot/Tpl2, is a negative regulator of Th1-type immunity through inhibiting IL-12 expression in antigen presenting cells (APCs) stimulated by Toll-like receptor (TLR) ligands. We here show that Cot/Tpl2(-/-) macrophages produce significantly less IL-23, an important regulator of Th17-type response, than the wild-type counterparts in response to lipopolysaccharide (LPS), which is a ligand for TLR4. The decreased IL-23 production in Cot/Tpl2(-/-) macrophages is, at least partly, regulated at the transcriptional level, as the LPS-mediated IL-23 p19 mRNA induction was significantly less in Cot/Tpl2(-/-) macrophages. Chemical inhibition of extracellular signal-regulated kinase (ERK) activity similarly inhibited IL-23 expression in LPS-stimulated wild-type macrophages. As Cot/Tpl2 is an essential upstream component of the ERK activation pathway of LPS, it is suggested that Cot/Tpl2 positively regulates IL-23 expression through ERK activation. These results indicate that Cot/Tpl2 may be involved in balancing Th1/Th17 differentiation by regulating the expression ratio of IL-12 and IL-23 in APCs.

Oxidative stress causes alveolar bone loss in metabolic syndrome model mice with type 2 diabetes.

BACKGROUND AND OBJECTIVE: Alveolar bone loss is caused by a host response to periodontal pathogens, and its progression is often enhanced by systemic conditions such as insulin resistance. Alveolar bone dehiscence has been observed in KK-A(y) mice, which are metabolic syndrome model mice with type 2 diabetes. The aim of this study was to investigate inducements responsible for alveolar bone dehiscence in the KK-A(y) mice. MATERIAL AND METHODS: The expression of endothelial nitric oxide synthase in the mandibles of mice was detected using immunohistochemical staining and the reverse transcription-polymerase chain reaction. After administration of N-acetylcysteine, an antioxidant, to KK-A(y) mice, alveolar bone loss and the expression of endothelial nitric oxide synthase protein in gingival keratinocytes and of hydrogen peroxide concentrations in plasma, were analyzed. The effect of hydrogen peroxide on endothelial nitric oxide synthase expression in keratinocytes was examined using cultured keratinocytes. RESULTS: The expression of endothelial nitric oxide synthase was decreased in gingival keratinocytes from KK-A(y) mice compared with gingival keratinocytes from control mice. Administration of N-acetylcysteine to the mice restored endothelial nitric oxide synthase expression in the gingival keratinocytes, suppressed the alveolar bone loss and decreased the hydrogen peroxide concentrations in plasma without the improvement of obesity or diabetes. In vitro, stimulation with hydrogen peroxide decreased the expression level of endothelial nitric oxide synthase in cultured keratinocytes, which was restored by the addition of N-acetylcysteine. CONCLUSION: Reactive oxygen species, such as hydrogen peroxide, are responsible for the alveolar bone loss accompanied by decreased endothelial nitric oxide synthase expression in KK-A(y) mice. Therefore, we propose a working hypothesis that the generation of oxidative stress is an underlying systemic condition that enhances alveolar bone loss in periodontitis occurring as a complication of diabetes.

Force-induced IL-8 from periodontal ligament cells requires IL-1beta.

During orthodontic tooth movement, mechanical stresses induce inflammatory reactions in the periodontal ligament (PDL). We hypothesized that chemokines released from PDL cells under mechanical stress regulate osteoclastogenesis, and investigated the profiles and mechanisms of chemokine expression by human PDL cells in response to mechanical stress. In vitro, shear stress and pressure force rapidly increased the gene and protein expressions of IL-8/CXCL8 by PDL cells. Consistently, amounts of IL-8 in the gingival crevicular fluid of healthy individuals increased within 2 to 4 days of orthodontic force application. The PDL cells constitutively expressed low levels of IL-1beta, which were not further increased by mechanical stress. Interestingly, neutralization of IL-1beta abolished IL-8 induction by mechanical stresses, indicating that IL-1beta is essential for IL-8 induction, presumably though autocrine or paracrine mechanisms. Finally, experiments with signal-specific inhibitors indicated that MAP kinase activation is essential for IL-8 induction.

Interferon-γ-producing B cells induce the formation of gastric lymphoid follicles after Helicobacter suis infection.

Helicobacter (H.) suis is capable of infecting various animals including humans, and H. suis infections can lead to gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Recently, we reported that interferon-γ (IFN-γ) was highly expressed in the stomachs of H. suis-infected mice, but the direct relationship between the upregulation of IFN-γ expression and the formation of gastric lymphoid follicles after H. suis infection remains unclear. Here, we demonstrated that the IFN-γ produced by B cells plays an important role in the formation of gastric lymphoid follicles after H. suis infection. In addition, IFN-γ-producing B cells evoked gastric lymphoid follicle formation independent of T-cell help, suggesting that they are crucial for the development of gastric MALT induced by Helicobacter infection.

Development of highly sensitive enzyme-linked immunosorbent assays for hepatocyte growth factor/scatter factor (HGF/SF): determination of HGF/SF in serum and urine from normal human subjects.

A sandwich enzyme-linked immunosorbent assay (ELISA) using rabbit anti-hepatocyte growth factor (HGF) IgG for human HGF, also known as the scatter factor, has previously been developed for determining increases in serum HGF levels in various liver diseases. The sensitivity limit of the ELISA is, however, approximately 0.2 ng/ml sample, and HGF concentrations in about 50% of normal subjects are not accurately measurable by this method, because the mean level of HGF in normal serum is close to the sensitivity limit. In the present study, chicken Fab' from egg yolk anti-HGF immunoglobulin Y and rabbit Fab' from rabbit anti-HGF IgG were conjugated with beta-D-galactosidase. With these conjugates as the second antibodies, we developed two sandwich ELISAs for human HGF and found that the sensitivities were about 20 pg/ml with the former conjugate and 2 pg/ml with the latter. The HGF concentration in sera from 138 normal subjects determined by the ELISA with the rabbit conjugate was 244+/-65 (SD) pg/ml serum, and it correlated very well with the number of leukocytes. Moreover, the ELISA with the rabbit conjugate permitted the determination of HGF levels in urine from normal subjects without first concentrating the sample. The determination of HGF in various biological fluids other than blood and urine by these ELISAs may aid the diagnosis and prognosis of various diseases.

Accessory function of human glioma cells for the induction of CD3-mediated T cell proliferation: a potential role of glial cells in T cell activation in the central nervous system.

Accessory function of human glial cells for the induction of anti-CD3 antibody-mediated proliferation of T cells was investigated by using seven glioma cell lines. Three of them were found to function as accessory cells and one of them, U118, was used for further analysis. U118 cells showed the cell-contact-mediated accessory function for T cell proliferation. It was found that protein synthesis was required to reveal this function, suggesting that some surface molecules are synthesized and expressed on U118 cells during interaction with T cells to mediate effective signals in T cells. Intercellular adhesion molecule-1 seemed to be one of such inducible molecules and was shown to contribute to effective accessory cell-T cell interaction, but necessity of other molecule(s) was also suggested.

Expression of prolactin mRNA in rat mammary gland during pregnancy and lactation.

We studied the expression of prolactin (PRL) mRNA in the mammary gland of resting, pregnant, lactating, and weanling rats using in situ and solution reverse transcriptase-polymerase chain reaction (RT-PCR). In mid- to late pregnancy and throughout lactation, PRL mRNA was detected in both in situ and solution RT-PCR. These PRL mRNA signals were clearly identified in the cytoplasm of alveolar and ductal mammary epithelial cells by the in situ RT-PCR method. In mid- to late pregnancy, such as at the initiating point of PRL mRNA expression, we confirmed in some cases a lack of PRL mRNA by solution RT-PCR. In addition, in the early weaning phase, no signals were detected by solution RT-PCR. However, slight focal signals were detected in some poorly vacuolated cytoplasm of regressing acinar cells by in situ RT-PCR. These findings suggest that PRL mRNA in rat mammary gland begins in mid- to late pregnancy in parallel with the development of the mammary gland, continues throughout lactation, and declines in the early phase of weaning, with regression of mammary epithelial cells.

Effects of peroxisome proliferator-activated receptor-alpha and -gamma agonist, JTT-501, on diabetic complications in Zucker diabetic fatty rats.

This study has investigated the effects of JTT-501, a peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-gamma agonist, on the pathogenesis of diabetic complications in the Zucker diabetic fatty (ZDF) rats, a model of type 2 diabetes. Comparison is made with troglitazone, a PPAR-gamma agonist. The ZDF rats exhibited hyperglycaemia and hyperlipidaemia, and developed diabetic complications such as cataract, nephropathy, and neuropathy. Treatment with JTT-501 from the prediabetic stage controlled glycaemia and lipidaemia, and prevented the development of diabetic complications. Troglitazone was less effective in controlling serum cholesterol and neuropathy. ZDF rats developed diabetic osteopenia with reduced bone turnover, and this was prevented by JTT-501 and troglitazone, possibly mediated by increased bone turnover and bone formation. Since JTT-501 controlled glycaemia and lipidaemia in ZDF rats and prevented several diabetic complications, it is suggested that treatment with JTT-501, which activates both PPAR-alpha and PPAR-gamma, could provide a valuable therapeutic approach against diabetic complications in type 2 diabetes.

Induction of cutaneous mast cell tumors by N-methyl-N'-nitro-N-nitrosoguanidine followed by TPA in female mice of 4 out of 5 strains tested.

Appreciable yields of cutaneous mast cell tumors were induced in a two-stage skin carcinogenesis protocol comprising N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) initiation followed by 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion in 4 of 5 strains of mice. Only female mice of each of the 5 strains were studied. The incidences of benign and/or malignant lesions differed considerably between strains; 27% in DBA/2, 22% in BDF1, 11% in BALB/c, 10% in CDF1 and 0% in C57BL/6 mice and no mast cell tumors were detected in any of the strains when treated with the initiator alone. First found in a DBA/2 mouse at week 50, most tumors were observed after 100 weeks of promotion, and were usually small in size (less than 2 mm in diameter) and predominantly located within the corium, although they occasionally extended into the subcutaneous tissue. Histologically, the benign mast cell tumors were composed of non-encapsulated, well circumscribed densely packed sheets of discrete cuboidal or rhomboid cells. Metachromatic granules were clearly visible in the cytoplasm by Toluidine Blue staining. Two of the tumors induced in DBA/2 mice were diagnosed as malignant mast cell tumors on the twin bases of cellular atypia and deep infiltration into the muscular layer. The cutaneous mast cell tumors were constantly accompanied by subepidermal mast cell aggregations which were also commonly observed in tumor-free skin of mice receiving the initiation-promotion procedure.

Long-term follow up study of vertical HTLV-I infection in children breast-fed by seropositive mothers.

Infection of Human T-lymphotropic virus type-I (HTLV-I) was investigated by long-term follow up surveys of mother's milk-fed infants. HTLV-I infections of infants via seropositive mother's milk, that is, anti-HTLV-I antibody-positive infants, increased in number up to the age 2, but no infants became antibody-positive thereafter. Infants who had became antibody positive by age 2 remained so at age 11-12. HTLV-I infection via feeding with mother's milk was established by the age 2. While in epidemiologic surveys an increase of the anti-HTLV-I antibody-positive rate has been reported, this survey revealed that after acquisition of HTLV-I from breast feeding, there was no further horizontal transmission prior to puberty.

Bottle-feeding can prevent transmission of HTLV-I from mothers to their babies.

Breast-feeding is a major factor in the vertical transmission of human T-lymphotropic virus type I (HTLV-I). We studied whether such transmission may be prevented by bottle-feeding. HTLV-I infection was detected by both HTLV-I antigen and antibody tests. Thirty bottle-fed babies were examined 24 months after birth; only one was found to be HTLV-I antigen-positive. This infection rate was lower than that for breast-fed babies in whom HTLV-I antigen was detected in 24 of the 31 24-month-old babies born to HTLV-I positive mothers in a previous study. These results suggest that most vertical transmission of HTLV-I is attributable to breast-feeding and can be prevented by bottle-feeding.

Long-term follow-up study of HTLV-I infection in bottle-fed children born to seropositive mothers.

Human T-lymphotropic virus Type-I (HTLV-I) infects children via mother's milk. Infection of Human T-lymphotropic virus Type-I (HTLV-I) was investigated by long-term follow-up surveys of modified milk-fed children. Our observations of modified milk-fed infants revealed that: 1 of 154 (0.6%) at year 1, 5 of 129 (3.9%) at 1.5 years, and 5 of 108 (4.6%) at year 2 were anti-HTLV-I antibody-positive. No infants or children became newly antibody-positive thereafter. Modified milk feeding could prevent the HTLV-I infection of infants from mothers in many cases, however the infants who had became anti-HTLV-I antibody-positive due to established infection by the age 2 remained positive at age 11-12 with persistent infections. Modified milk-fed infants who had been born from HTLV-I seropositive mothers did not show that they had complete protection from HTLV-I infection, but a low infection rate was seen, showing that modified milk feeding is useful to protect from HTLV-I infection.

The micronucleus assay with peripheral blood reticulocytes by acridine orange supravital staining with 1-beta-D-arabinofuranosylcytosine.

Dose-dependent induction of micronuclei with 1-beta-D-arabinofuranosylcytosine (ara-C) was clearly shown in CD-1 mouse peripheral blood reticulocytes (RETs) using an acridine orange (AO) supravital staining method, as well as in the conventional bone marrow assay. The maximum frequencies of micronucleated RETs (MNRETs) in peripheral blood and of micronucleated polychromatic erythrocytes (MNPCEs) in bone marrow were comparable, as shown in two laboratories independently. The maximum frequencies of MNRETs in peripheral blood lagged about 24 and 12 h behind those of MNPCEs in bone marrow in experiments with 24- and 12-h sampling intervals, respectively. The proportion of each type of RET was examined periodically after treatment with ara-C at doses ranging from 6.25 to 50.0 mg/kg. The proportion of type I RETs among total RETs decreased 24 or 48 h after treatment according to the dose level. This suggest that this ratio could be a good indicator of the bone marrow cell toxicity of test chemicals.

Structure-dependent variation in the mutagenic, prophage-inducing and antibacterial activities of 5-nitro-2-furamide derivatives.

A comparative survey of the mutagenic, prophage-inducing and antibacterial activities of 3 structure-related series of 5-nitro-furan derivatives including 5-nitro-2-furohydrazide imide, 5-nitro-2-furamide oxime and 5-nitro-2-furohydrazide has been undertaken. Among the compounds assayed, the 5-nitro-2-furohydrazide imide series was found to be most active with regard to mutagenic and antibacterial activities against Salmonella typhimurium TA100 and prophage-inducing activity in Escherichia coli GY5027. A clear correlation was observed between the chemical structure and the mutagenic and prophage-inducing activities which were approximately correlated to the antibacterial activity.

Combined mutagenicity of cobalt(II) salt and heteroaromatic compounds in Salmonella typhimurium.

Mutagenic activities of 4-aminopyridine (4AP), 4-aminoquinoline (4AQ), 9-aminoacridine (9AA) and harman (HM) were examined by the Salmonella test system in the presence of cobalt(II) chloride (CoCl2), which itself is non-mutagenic in this system. Mutagenic activity of the mixture of 9AA and CoCl2 was found to be much higher than that of 9AA alone in strains TA1537 and TA2637. A similar enhancing phenomenon was observed in 4AQ-CoCl2 and HM-CoCl2 mixtures but not in that of 4AP-CoCl2. Judging from visible and nuclear magnetic resonance spectral data, this increased mutagenicity may be attributable to the formation of moderate to weak complexes between these chemicals and the Co(II) cation. A survey of the mutagenicity of several Co(II) complexes supported this interpretation.

Genotoxic activities in vivo of cobaltous chloride and other metal chlorides as assayed in the Drosophila wing spot test.

A series of metal chlorides were subjected to the wing spot test of Drosophila melanogaster. In the test, larvae trans-heterozygous for the wing-hair mutations mwh and flr were orally treated at the third instar stage with a test compound and the wings were inspected at the adult stage for spots expressing phenotypes of the markers. CoCl2, MnCl2, MoCl3, NiCl2 and ZnCl2 were clearly effective in inducing spots with one or two mutant hairs (small spots). CoCl2 was clearly effective in inducing spots with three or more mutant hairs (large spots) as well. CrCl3, FeCl2 and FeCl3 were negative under the conditions used. Based on estimated frequencies of small spots induced at the LD50, the genotoxic effectiveness of the positive metal salts were ranked in a sequence of CoCl2 > ZnCl2 > MoCl3 > (MnCl2, NiCl2). Since CoCl2 did not induce large spots in the wings of the mwh/TM3 flies with a suppressed ability of mitotic crossing-over, the large spots induced by this compound in the mwh/flr system were ascertained as mutant clones due to mitotic crossing-overs.