Helicobacter pylori infection enhances N-methyl-N-nitrosourea-induced stomach carcinogenesis in the Mongolian gerbil

No previous report has demonstrated the relationship between Helicobacter pylori (HP) infection and gastric carcinogenesis in an experimental animal model. A total of 170 male Mongolian gerbils (MGs) were divided into nine groups (18 < or = n < or = 20 for each group). MGs of four groups were inoculated with HP before or after continuous N-methyl-N-nitrosourea (MNU) administration via the drinking water. Both intestinal-type and diffuse-type adenocarcinomas, including signet ring-cell carcinomas, were found at 40 weeks after the study commenced, but only in the HP inoculation groups with MNU exposure and not in the MNU alone or HP inoculation alone control groups. The present findings demonstrate that HP infection increases the incidence of MNU-induced adenocarcinoma of the glandular stomach in MGs.     

Simulation of Mode Interaction in the Gyrotron FU CW I

A series of experiments carried out in order to study the operational performance and oscillation characteristics of a 300 GHz/3.5 kW gyrotron FU CW I have demonstrated a complicated behaviour which is attributed to multimoding phenomena. In this paper we present and discuss some initial results from computer simulation of mode interaction in this tube. They give a better insight in the underlying processes, possible excitation conditions of various competing modes and suggest some directions for continuation of this investigation.     

Characteristics of the mode converter of Gyrotron FU CW GII radiating Gaussian beams in both the fundamental and second harmonic frequency bands

Gyrotron FU CW GII, the second gyrotron of the Gyrotron FU CW G-series with an internal quasi-optical mode converter, was recently developed at the Research Center for Development of Far-Infrared Region, University of Fukui (FIR FU) [Y. Tatematsu et al., J. Infrared, Millimeter, Terahertz Waves 35, 169 (2014)]. The design oscillation mode of this gyrotron is TE_8,3 with a corresponding frequency of 393.4 GHz in the second harmonic cyclotron resonance. We observed oscillations of different modes including fundamental harmonic modes in the 200-GHz band upon varying the strength of the magnetic field in the cavity. Radiation patterns corresponding to these modes emitted from the window were Gaussian although the internal mode converter was designed for the TE_8,3 mode. The directions of the radiated Gaussian beams were found to depend on the oscillation modes with a relation similar to that obtained for another gyrotron that was also equipped with a mode converter. This relation is explained based on geometrical optics. Moreover, numerical calculation with the electromagnetic wave code developed in FIR FU confirmed the same relation. The observed features of the Gyrotron FU CW GII show that it can serve as a unique power source with two frequency bands at 200 and 400 GHz. This result provides a way of developing multiple-frequency gyrotrons.     

Bacteriological study of oral open abscesses

Although studies of bacteriology of closed oral abscesses have been extensively done, there are few studies on microorganisms involving open oral abscesses. We examined bacteriologically three open abscesses with precaution against bacterial contamination with oral normal flora and saliva, when sampling. The specimens were subjected to aerobic and anaerobic cultures within 2 hours after sampling. All three cases were infected with 5 to 14 species of aerobic and anaerobic bacteria; Streptococcus spp., Prevotella intermedia and other Prevotella spp. were predominant in all three cases. All six Prevotella spp. isolated were beta-lactamase producers, being resistant to beta-lactam antibiotics. These results emphasize the importance of prompt anaerobic culture for the bacteriological study of open oral abscess and the significance of nitrocefin test to detect beta-lactamase produced by oral isolates, especially Prevotella spp.     

Sparse distribution of hepatocyte growth factor-producing cells inside hepatocellular foci in rats treated with hepatocarcinogens

The distribution of hepatocyte growth factor (HGF)-synthesizing cells in rat liver during development of glutathione S-transferase P form (GST-P)-positive nodules after diethylnitrosamine initiation followed by promotion with 2-acetylaminofluorene plus partial hepatectomy (PH) was investigated using in situ hybridization. HGF-producing cells were non-parenchymal in nature, and were suspected to be mainly of Kupffer type. They were mostly located outside GST-P-positive lesions, in the surrounding parenchyma. In the oval cell proliferation phase 1 week after PH, they increased and they were mainly localized around the portal triads. It is concluded that HGF is directly involved in an endogenous paracrine growth pathway controlling proliferation in oval cells and in normal, but not GST-P-positive, hepatocytes.     

Effect of tetracycline and some pharmaceutical adjuvants on the capillary and the lymphatic transport of sulfanilic acid from the rat small intestine

Three children with hypothalamic mass lesions and continued linear growth in the absence of circulating growth hormone are presented. Serum growth hormone levels were either undetectable or very low both basally and following insulin-induced hypoglycaemia, whereas serum somatomedin levels were normal. Two subjects had elevated serum levels of prolactin, and in one of these prolactin suppression with bromoergocryptine failed to influence either somatomedin levels or urinary excretion of nitrogen, hydroxyproline and calcium. Although only one case was studied in detail these data suggest that maintenance of serum somatomedin and of normal growth in these children was not dependent upon prolactin secretion.     

Development of a kW Level-200 GHz Gyrotron FU CW GI with an Internal Quasi-optical Mode Convertor

Development of gyrotrons with an internal mode convertor has started in Research Center for Development of Far-Infrared Region, University of Fukui (FIR FU). As the first gyrotron of such a kind, we have designed and manufactured Gyrotron FU CW GI. It operates at 203 GHz at fundamental cyclotron resonance. We have designed a cavity and a mode convertor under some constraints such as reuse of an electron gun and small diameter of a magnet bore. Designed output power is about 1 kW. We have succeeded in observation of a circular radiation pattern. The maximum observed output power is 0.5 kW for the setting cathode voltage of 20 kV and the beam current of 0.5 A. This success makes gyrotron development in FIR FU to proceed to a new stage.     

Analysis of discrepancies between VCG and ECG interpretation of anterior wall myocardial infarction

In 247 cases in which an old anterior myocardial infarction (MI) was suspected and in which SVEC III-lead system vectorcardiograms (VCGs) and matching conventional 12-lead electrocardiograms (ECGs) were available, records were analyzed to investigate the diagnostic agreement or discrepancy between the two techniques. The frequency of agreement (155 cases) exceeded the frequency of disagreement (92 cases), but the frequency of disagreement even with lumped subgroups was high. Eighty percent of this disagreement was between positive VCG and negative ECG diagnostic consensus. The positive MI group by ECG diagnosis showed smaller R waves and larger S waves and larger S waves in leads V2 and V3 and smaller R/S ratios in leads V2 and V4 than the negative MI groupe by ECG, while small R waves or QS patterns and large S waves in just lead V1 were the only positive finding in the positive MI group by VCG. The important VCG characteristic for positive MI diagnosis was abnormal posterior deviation of the initial QRS vectors. The high incidence of discrepancies shown by positive VCG and negative ECG diagnoses resulted from the fact that, in spite of the presence of a fairly well developed R wave in precordial leads, the initial QRS vectors were displaced posteriorly. In 8 of 18 cases classified into negative VCG and positive ECG diagnostic group, poor R wave progression did not necessarily result in the posterior displacement of the initial QRS vectors. In contrast to the difficulties in applying ECG criteria for anterior MI (variability of QRS patterns in precordial leads), an orthogenal VCG (representing the phasic changes in the depolarization process) seems to clarify the equivocal situation in the ECG diagnosis of MI.