Passband widening of transversely coupled resonator filters using the fundamental symmetric and antisymmetric modes.

This paper describes a method for widening the passband of transversely coupled resonator filters (TCF) using only the fundamental symmetric and antisymmetric modes. The coupling of modes analysis in the transverse direction is applied to the TCF design to investigate the passband width. As a result, it is found that the passband width can be increased by making the surface acoustic wave (SAW) velocity difference between the interdigital transducer (IDT) region and the resonator gap region smaller. It is proposed that a grating structure be applied to the common ground bar, instead of the uniform metal, to reduce the SAW velocity difference. Using the grating-type common ground bar, filters are fabricated on ST-quartz substrate. The passband of a single filter with a center frequency of 248 MHz is widened up to 410 kHz without any increase of the insertion loss. The effect of the impedance mismatch at the junction of two cascaded devices is investigated. It is shown that the filter performance is improved by reduction of the small parasitic capacitance existing at the cascade point. Experimentally, the capacitance formed between the bus bar of the IDT and the bottom surface of the ceramic package is reduced. The insertion loss is reduced by 0.6 dB, and 3-dB passband is widened by 8 kHz for a filter with a center frequency of 248 MHz. On the basis of these two improvements, cascaded TCFs are fabricated. For a filter with a center frequency of 248 MHz, an insertion loss of 5.5 dB and a 3-dB passband width of 270 kHz are obtained.

Effects of medical treatment on gastric mucosal abnormalities in gastroduodenal ulcer disease.

The development of carcinoma in cases of gastric ulcer disease during long-term H(2)-blocker treatment is slowly increasing, and ulcers that require such treatment exhibit the characteristics of intractable conditions, including linear ulcers, simultaneous gastric and duodenal ulcers, immature intestinal metaplasia of the gastric epithelium, and atrophic gastritis accompanied with multiple ulcer cicatrices. The incomplete form of intestinal metaplasia resembling Filipe's type III lesions and showing structural atypia developed in the background gastric mucosa in such cases, and the characteristics of this metaplasia included structural atypia, a residuum of gastric-type mucous cells, rapid proliferative activity, and in some areas abnormal expression of P53 protein. In addition, in rat studies it was demonstrated that prolonged administration of H(2)-blockers while gastric ulcers were present accelerated cell proliferation in the background gastric mucosa in the long term. Accordingly, it was considered possible that the development of the incomplete form of intestinal metaplasia, which was strongly suggested to have some relation to the sites where intestinal-type gastric carcinoma appeared, was accelerated by mucosal injury due to chronic ulcers and by persistent elevation in intragastric pH. The results of the present study of gastric carcinoma as a complication of peptic ulcer disease indicated the possibility that Helicobacter pylori was a major contributory factor to the development of the incomplete form of intestinal metaplasia from damage to the background mucosa, but it was unclear whether H. pylori made any direct contribution to carcinogenesis.

A novel reflector-filter using a SAW waveguide directional coupler.

The SAW waveguide technique was used to form a novel reflector-filter for the realization of compact IF filters in CDMA handsets. The reflector-filter design is an attractive technique to obtain characteristics with steep skirts in a short device length, because the SAW propagation path is folded and the frequency response is synthesized by utilizing both IDT and reflector responses. In this paper, we propose a new reflector-filter structure using a SAW waveguide directional coupler. For the implementation of the proposed reflector-filter, the key technology is the design of SAW waveguides. We have formed SAW waveguides using Al gratings loaded on the surface of the substrate. The pitch of the Al gratings has been chosen unequal to half the acoustical wavelength to avoid the occurrence of the gratings stopband at the filters passband position. Using the proposed reflector-filter structure, PCS-CDMA IF filters were fabricated on quartz substrates. The filter exhibited an insertion loss of 8.5 dB, a 5 dB bandwidth of 1.45 MHz, and a rejection of more than 33 dB at the center frequency +/-1.25 MHz with the package size of 4.8x9.1 mm (2). i.e., half the size of a conventional transversal filter was achieved using the proposed reflector-filter technique.

[Biochemical and immunohistological changes in the gastric mucosa of rats with long-term administration of histamine H2-receptor antagonist].

Effects of long term administration of Histamine H2-receptor Antagonist (H2-RA) in the treatment of peptic ulcer was studied for the influence to the risk of causing precancerous changes in gastric mucosa. Serum gastrin. ODC activities, polyamine and PCNA labeling index were biochemically and immunohistologically observed. Rat's mucosae with experimentally induced peptic ulcer treated with long term H2-RA, showed no morphological changes but at 30 weeks of H2-RA, had significantly higher value in PCNA labeling index and in polyamine (spermidine) quantity compared to control H2-RA alone and ulcer alone groups. These results suggest that long term administration of H2-RA, even after healing of the ulcer, may cause the gastric mucosa to possess a milieu in favour of precancerous changes, due to the increased proliferative activity of the cells.

[Usefulness of contrast-enhanced CT of the peritoneum to evaluate efficacy of neoadjuvant chemotherapy for peritoneal dissemination in an advanced gastric cancer case].

We performed contrast-enhanced CT before and after chemotherapy in a patient with advanced gastric cancer to assess the efficacy of neoadjuvant chemotherapy for peritoneal dissemination. The patient was preoperatively given combined chemotherapy with UFT and CDDP. Hepatic metastatic and peritoneal disseminated foci were markedly reduced on CT. Thus CT proved to be useful for assessing peritoneal dissemination and the efficacy of neoadjuvant chemotherapy.

[Therapy for the gastric cancer in the near future].

Through the review of recent Japanese literatures, anticipated ways of the treatments for the gastric cancer in the near future were discussed. Most hopefully, no surgical intervention with the prevention and early diagnosis of initiation or promotions of the cancer development by genom analyses in individuals who may have high risk gene mutations will be expected. In the near future periods, however, vigorous molecular biological investigations for purpose will be required to clarify the mechanisms and each biological characteristics of the cancer developments. Further improvements of endoscopic ultrasonography and electron endoscopy will be needed for "early" detection of the lesions in the high risk group patients. More finely defined minimally invasive or extended operative procedures will still be challenged for molecular-biologically identified malignancies of the disease. Immuno-chemotherapy and chemotherapy aided by gene therapy will be the greatest hoperfull ways to conquer the disease. Direct concerns at the moment, however, cancer developments in the stomach with benign "ulcer" infected with Helicobacter Pylori must be urgently integrated for the prevention of the disease. Post-operative disorders after any type of surgery will still be one of the great issue in this until the complete achievements of above mentioned future tasks.

[Effect of neoadjuvant chemotherapy (CDDP.UFT therapy) upon cell DNA analysis by flow cytometry in gastric carcinoma].

Neoadjuvant chemotherapy with CDDP and UFT was performed on far advanced gastric carcinoma cases whose curative resection was impossible. These trials were carried out on 10 patients who had Borrmann 4 type carcinoma. PR was found in 6 cases, for an efficacy rate of 60% (6/10). The DNA content in gastric carcinoma was determined before and after treatment by flow cytometry. The relationship between the change of DNA ploidy pattern and effects of chemotherapy was investigated. Aneuploidy was found in 6 of 10 patients (60.0%). DNA ploidy patterns showed no correlation with effectiveness. In aneuploid cases, the group of responders showed seemingly the change of ploidy pattern, from aneuploid to diploid. In non-responders the percentage of aneuploid cells increased. In diploid cases, an accumulation of S-phase fraction was observed in the group of responders. These results suggested that DNA ploidy analysis may provide additional diagnostic criteria for better assessment of chemotherapeutic effects.

In vitro and in vivo evaluation of a sustained release preparation containing phenylpropanolamine hydrochloride.

The relationship between dissolution behaviour and plasma concentration after administration of a sustained-release preparation containing phenylpropanolamine hydrochloride was studied in 11 male volunteers. The testing for dissolution was carried out using the JP X rotating basket procedure, and human plasma samples were assayed for phenylpropanolamine hydrochloride by a specific high-performance liquid chromatography. Three hours after dosing, the mean peak plasma concentration was 104.1 ng/ml and the plasma concentration declined with a half-life of 4.85 h. The time course of plasma and dissolution data were analyzed by a non-linear least squares curve fitting method to compare in vivo and in vitro release behaviour. Plasma concentration changes of phenylpropanolamine hydrochloride were correlated with in vitro release behaviour of the sustained-release preparation.

Bioavailability of indomethacin capsules in humans (III): Correlation with bioavailability in beagle dogs.

The bioavailabilities of five indomethacin capsules were studied in ten beagle dogs and correlations with the in vivo results in humans and dissolution rates were investigated. The difference in bioavailability between two commercial products was smaller in dogs than in humans, which seemed to be due to strong disintegration forces in dogs. The difference in the dissolution rate among the products was reflected less in the Tmax in dogs than in humans, and the Tmax was shorter in dogs which seems to be due to faster gastric emptying and passage of the drug through the absorption site in dogs. Gastric acidity effects on the indomethacin availability found in humans were not observed in dogs. The Cmax and Tmax correlated well with the in vitro dissolution rates, but AUC24 did not. The Cmax and Tmax in dogs also correlated with the corresponding parameters in humans, especially those in high gastric acidity humans, but AUC24 did not.

Determination of the anti-ulcer agent geranylgeranylacetone in serum by gas chromatography-mass spectrometry.

A highly specific and sensitive method for the determination of the anti-ulcer drug geranylgeranylacetone (GGA) in human serum is described. The extract from serum with hexane was saponified with potassium hydroxide and subjected to silica gel column chromatography to remove interfering substances. GGA in the partially purified extract was then reacted with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine and measured by selected ion monitoring using gas chromatography--mass spectrometry. A low detection limit (1 ng/ml) and high precision were obtained.