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Biomedical subjects

M Yamamura

Publications and source records attributed to M Yamamura.

At least 217 records · Page 12Linked to original sources
PubMed1989

Influence of fecal anorexigenic substance (FS-T) on plasma amino acids in Wistar and Zucker obese (fa/fa) rats.

An anorexigenic substance (FS-T), found in feces, isolated and injected intraperitoneally, induced significant feeding suppression in Wistar rats and in genetically obese Zucker rats (fa/fa) and their lean littermates. The concentration of total plasma amino acids 2 h after FS-T injection (the time of maximum feeding suppression) was 71.0, 68.6 and 60.2% of that of controls for Wistar and Zucker obese and lean rats, respectively. By 48 h after injection of FS-T, food intake and the concentration of total plasma amino acids had returned to normal. Plasma tryptophan levels and the ratio of tryptophan to neutral amino acids were also monitored to elucidate the relation between FS-T and appetite. Two h after injection of FS-T, the ratio of tryptophan to neutral amino acids had increased in Wistar rats, while no change was detected in either obese or lean Zucker rats. However, no change was observed in plasma glucagon levels in Wistar rats, but a significant increase was found in both obese and lean Zucker rats at 2 h after FS-T injection.

Amino Acids↗
PubMed1989

Synthesis and central nervous system actions of thyrotropin-releasing hormone analogs containing a 1-substituted 2-oxoimidazolidine moiety.

A series of thyrotropin-releasing hormone (TRH) analogs in which the pyroglutamic acid residue was replaced by (S)-2-oxoimidazolidine-4-carboxylic acid (Oic-OH) and the related derivatives was prepared, and the central nervous system (CNS) actions were examined. Of these, 1-benzyl-Oic-His-Pro-NH2 (2c) showed the most potent activities, which were 1.5-8 times greater than those of TRH. Moreover, the thyrotropin (TSH)-releasing activity of 2c was about 1/16 times weaker than that of TRH.

Animals↗
PubMed1989

Effects of mafoprazine, a phenylpiperazine derivative, on the central dopaminergic system.

The effects of mafoprazine, a new phenylpiperazine derivative, on the central dopaminergic system were studied. Mafoprazine, like chlorpromazine and haloperidol, reduced the apomorphine-induced cage-climbing behavior in mice, emesis in dogs and stereotyped behavior in monkeys; methamphetamine-induced hyperlocomotion and group toxicity in mice; and agitation in rats. Mafoprazine inhibited the unilateral circling behavior induced by methamphetamine and apomorphine in rats with 6-hydroxydopamine-induced lesions in the unilateral nigrostriatal neuronal tract. The potency of mafoprazine in these experiments was almost equal to that of chlorpromazine and about one-tenth that of haloperidol. The cataleptogenic activity of mafoprazine was lower than those of chlorpromazine and haloperidol. Mafoprazine potentiated clonidine-induced hypothermia. These results suggest that mafoprazine has a relatively selective postsynaptic dopamine D2-receptor blocking action in the nucleus accumbens compared with chlorpromazine and haloperidol and suggest that mafoprazine also has alpha 2-adrenoceptor-stimulating actions.

Aggression↗
PubMed1989

Effectiveness of peanut agglutinin-binding glyco-related antigen and cyclophosphamide on metastasis of Lewis lung carcinoma.

Soluble tumor-associated antigens were isolated from Lewis lung carcinoma (3LL) cells by detergent solubilization and purified by affinity chromatography on peanut agglutinin (PNA)-agarose. Subcutaneous injection of PNA-binding glyco-related antigen into 3LL-bearing male C57BL/6 mice significantly augmented delayed-type hypersensitivity (DTH), and also inhibited the growth of the primary 3LL tumors. The effects of combined immunotherapy and chemotherapy with this antigen and cyclophosphamide (CY) were examined following excision of 3LL by determining the number of pulmonary surface nodules and wet weight of the lungs. Injection of PNA-binding glyco-related antigen and CY significantly inhibited pulmonary metastasis and prolonged the survival of the mice. The spleen cells obtained from mice with combined treatment showed higher neutralizing activity against 3LL cells than other groups. Therefore, combined immuno and chemotherapy may be useful in preventing metastasis.

Animals↗
PubMed1989

[Study of objective assessment for pathways in areas of intercuspal position during masticatory movements].

Masicatory function is the result of a highly complicated neuromuscular activity which coordinates in stomatognathie system. Functional directions of masticatory cycles in areas of intercuspal position (IP) were objectively evaluated on each stroke obtained through the Sirognathography Analyzing System (S. G. G./A. S.; Siemens, W. Germany). Twenty seven dantate subjects were selected at random from students and staff members of Kanagawa Dental College. A piece of chewing gum was given to each subject to masticate it for a minute on one side and on the other side respectively. A total of masticatory cycles were successively recorded into S. G. G./A. S.. A statistical analysis, the equal probability for ellipstical variations, was made on the angular measurements from opening and closing phases of each cycle within 3 mm from onset and terminus in areas of IP during masticatory movements. Four characteristic features of angular measurements are presented, namely, subjects who showed different types in position and forms by plotted angles within 80% of total amounts. The following results were obtained from this study. 1. Functional directions of masticatory cycles are clearly recognized in areas of IP from opening and closing phases during masticatory movements. 2. An application of the equal probability for ellipstical variations seems to be efficient for the functional analysis of masticatory cycles. 3. A classification of different types of plotted angles contributes to become a basis for diagnosis of masticatory function and occlusion.

Dental Occlusion↗
PubMed1989

[Mechanical evaluation of crown restoration by means of laser holographic interferometry, with a primary regard to establish a system for an experimental method].

This study was conducted to perform mechanical evaluations of crown restorations by Laser Holographic Interferometry (LHI). However, in an application of LHI, the Fujinon Holox FHLX-II system (He-Ne Gas Laser GLG-5700, NEC Co.) to this experiment, it was mandatory to do some modifications for loading and measuring evaluations, thereby a whole sequence of this system could be successfully carried out. The experiments were conducted in the following manner: Ten pieces of full cast crowns were constructed by a conventional procedure with 12% Au-Ag-Pd alloy and each test-piece was cemented alternately by zinc phosphate cement on a master die (stainless steel) with a chamfer margin. Successive vertical loadings (0kg-30kg) were applied for each test-piece and holograms were taken for crown restorations under loadings of both 15Kg & 30Kg with an accuracy of 0.3 micron. Three-dimensional measurements of nine points on surface of a testpiece were obtained through interference fringes, which were converted into mathematical values and statistical comparisons were performed for mean values under loadings of both 15 Kg & 30 Kg. The following results were obtained from this experiment. 1. It was successfully performed that an application of Laser Holographic Interferometry (a real time) became an efficient method with some modifications for mechanical evaluations of crown restorations. 2. Besides modification for rigid fixation of a test-piece, it made possible to conduct the loading experiment under Kg unit, which was impossible in previous studies. 3. Three-dimensional measurements were also made possible by an application of mathematical calculations, thereby a total system of experimental procedures was established. 4. Reference points were marked on surface of a test-piece, and this made possible to compare with the displacement values of other test-pieces. 5. Displacements of experimental crowns with both 15 Kg & 30 Kg under areas of loadings showed remarkably and they were gradually spread out toward the outer directions of restorations with slight displacements. From this experiment, it was proved that a cemented crown showed a certain deformational behavior under loadings. Therefore, this system contributes to become an efficient method evaluating mechanical features of crown restorations for further studies.

Crowns↗
PubMed1989

[A case of giant leiomyosarcoma that grew exogastrically in a year and four months].

Presented is a 69-year-old female who had gigantic leiomyosarcoma showing a pedunculated and exogastric growth. Though the patient had been diagnosed as having a gastric submucosal tumor (SMT) on being given an upper GI series and an endoscopical examination, she did not enter hospital until a year and 4 months later. On admission, a large SMT was suspected after an upper GI series and an endoscopic examination. Computed tomography (CT), ultrasonography (US), and angiography revealed a gastric SMT that had grown exogastrically. Subsequently, this tumor was resected with the gastric wall. Histologically, tumor was determined as being a leiomyosarcoma. CT and US were found useful in demonstrating the SMT with its exogastric growth.

Aged↗
PubMed1989

[A new high-yield continuous cell culture system and its clinical application in adoptive immunotherapy with LAK cells].

We developed a high-yield culture system, consisting of a culture bag on a rotator. The culture bag has two compartments, an inner compartment separated from an outer compartment by a semipermeable membrane. Cells in an appropriate culture medium are placed in the inner compartment, and medium without serum is placed in the outer compartment. The bag is rotated at an angle of 45 degrees between 0.5 and 5 rpm in a 37 degrees C incubator. The medium is changed in the outer compartment at intervals when needed. The outer compartment acts as the feeder as well as allows catabolites to diffuse through the culture. In addition, since the system is a closed-system, sterile conditions can easily be maintained. Using this system, we demonstrated that up to 20 X 10(6) cells/ml of PBMC could be cultured in IL-2 with sufficient recovery rate and cytotoxicity.

Cytological Techniques↗
PubMed1989

[A case report of Swyer-James syndrome].

A 43-year-old man with Swyer-James syndrome (SJS) was reported. The left side of his chest radiograph and computed tomogram was hyperlucent with decreased vascular markings. Pulmonary angiogram and scintigram showed markedly decreased blood flow of the left lung. Statistical study of the patients with SJS in Japan was done.

Adult↗
PubMed1989

[Tumor metastasis and the fibrinolytic system].

Metastatic spread of malignant tumor appears to correlate with activation of the fibrolytic system. The role of fibrinolysis in growth and metastasis was examined in Lewis lung carcinoma of mice. The inhibition of fibrinolysis or proteases decreased the primary tumor growth and pulmonary metastasis, whereas the activation of fibrinolysis or proteases increased the number of metastatic foci in the lung. Electronmicroscopically, thrombus formation in the primary site prevented tumor invasion and metastasis formation. Plasminogen activator (PA) content of excised tumors was determined by SDS-PAGE, and major PA was found to be urokinase (UK) type. Immunohistochemical study with specific antisera was done. When tumor cells possessed a high level of UK, laminin and type IV collagen, components of the basement membrane, disappeared from tumor tissues. These findings suggest that PA through protease cascade plays a role in tumor invasion and metastasis. Clinically, patients with advanced cancer are usually in a hypercoagulable state with elevated fibrinogen, and fibrin deposition around tumor mass is a serious problem in cancer chemotherapy. UK infusion prior to 5-fluorouracil increased tissue concentration of antitumor agent. However, development of consumption coagulopathy characterized by progression from hypercoagulable state to disseminated intravascular coagulation has also been found in several cases.

Animals↗
PubMed1988

Effect of dietary eicosapentaenoic acid on azoxymethane-induced colon carcinogenesis in rats.

The effects of eicosapentaenoic acid (EPA, n-3 polyunsaturated fatty acid) and linoleic acid (n-6 polyunsaturated fatty acid) on azoxymethane-induced colon carcinogenesis in rats were studied. Male Donryu rats were given two types of semipurified diet containing 4.7% EPA plus 0.3% linoleic acid and 5% linoleic acid. The rats were given s.c. injection of azoxymethane (7.4 mg/kg body weight once a week for 11 weeks) and sacrificed 15 weeks after the last injection of azoxymethane. The tumor incidence and tumor yields (tumors per rat) of the colon were significantly lower in rats on the EPA diet compared to those on the linoleic acid diet; i.e., 33%, 0.41 +/- 0.61 and 69%, 1.66 +/- 1.69, respectively. In the analysis of phospholipid fatty acid composition, the colon tumor showed higher levels of arachidonic acid and lower levels of linoleic acid than those in the normal colon mucosa in both diet groups. Despite the increase of arachidonic acid in colon tumor, the EPA diet suppressed the excessive production of prostaglandin E2, which may be accompanied with neoplastic formation, whereas linoleic acid diet caused a marked increase in the tumor content of prostaglandin E2 compared to normal colon mucosa. These results suggest that EPA exerts its inhibitory effect on colon carcinogenesis by modulating lipid metabolism and inhibiting prostaglandin E2 synthesis in tumor cells.

Animals↗
PubMed1988

The production of anorexigenic substances by intestinal flora.

The role of intestinal flora in the production of anorexigenic substance was investigated. Proteus mirabilis (P. mirabilis) and Escherichia coli (E. coli) were found to produce an anorexigenic substance, while Enterococcus faecalis (E. faecalis, type 1 and 2) and Staphylococcus intermedius (S. intermedius) did not. The anorexigenic substance was purified and was detected as, a single though broad band by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The specific activity of the final form of the purified substance was 120 units/mg carbohydrate. The substance contained no protein residue and appeared to be a lipopolysaccharide. The evidence that intestinal flora produces an anorexigenic substance leads to an interesting assumption that the intestinal flora may be responsible for regulating food intake.

Animals↗
PubMed1988

Heat production as a quantitative parameter of phagocytosis.

Microcalorimetry was applied to measure phagocytosis by human peripheral blood neutrophils and monocytes. Heat production was 9.1 +/- 2.6 microW by 1 X 10(6) unstimulated neutrophils and increased to 28.4 +/- 3.2 microW in association with phagocytosis. The increase in heat production was directly proportional to the number of Saccharomyces cerevisiae particles phagocytosed as well as to the concentration of opsonizing serum. No heat increase was observed in the absence of phagocytosis. An increase in heat production by monocytes was also observed in association with phagocytosis, but it was much less obvious than that by neutrophils. Heat production can thus be used as a quantitative measure of phagocytosis.

Calorimetry↗
PubMed1988

Carcinoma of the colon in children: report of a case and review of the literature.

Carcinoma of the colon seen in an 11-year-old boy is reported herein. The patient had advanced carcinoma of the ascending colon and died 8 months after an ileo-transversostomy had been performed as a palliative procedure. Histologically, the tumor was found to be signet-ring cell carcinoma. 29 cases of colon carcinoma reported in Japanese children under 15 years of age are also reviewed. In 19 of these patients, surgery was done as an elective procedure after the diagnosis of colon cancer had been established, but emergency surgery was performed on 10 patients for perforation or obstruction of the bowel. Curative resection was possible in 14 patients, but of these, only 3 patients survived for more than 10 years.

Adenocarcinoma, Mucinous↗
PubMed1988

Effects of elevated temperature on growth, respiratory-deficient mutation, respiratory activity, and ethanol production in yeast.

Some mesophilic yeasts and a thermotolerant strain of Saccharomyces cerevisiae were found to grow at 40 degrees C in complex media containing 1% yeast extract when an inoculum of 10(6) or more cells.mL-1 was used. Yeast extract (6%) permitted Saccharomyces cerevisiae to grow at 40 degrees C even with a smaller inoculum size (10(5) cells.mL-1). The fraction of respiratory-deficient (petite) mutants in 40 degrees C grown culture was less than 10% except for the thermotolerant strain, which showed greatly increased levels depending on culture conditions. Seven of eight yeast strains exhibited extremely reduced cytochrome oxidase activity when grown at 40 degrees C irrespective of the frequency of the petite mutation. In contrast, the accumulation of ethanol in the medium and the ethanol-producing activity of the cells were not affected by growth at 40 degrees C.

Culture Media↗