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T Shimamura

Publications and source records attributed to T Shimamura.

At least 163 records · Page 9Linked to original sources
PubMed1991

Influence of dietary fish oil on the aortic, myocardial, and renal lesions of SHR.

To examine the effects of menhaden oil on the progressive glomerulosclerosis, arteriosclerosis, plasma cholesterol and triglyceride levels, and myocardial damage, spontaneously hypertensive rats (SHR) were fed Purina rat chow supplemented either with 6 g % of menhaden oil or with 6 g % of corn oil. They were sacrificed on the 12th and 18th months, and the kidneys, aorta, and heart were examined by light microscopy. At sacrifice, body weight, plasma creatinine, systolic blood pressure, 24 h' urinary protein output, total plasma cholesterol and triglyceride, glomerular filtration rate (GFR), and glomerulosclerosis index were measured. There was no significant difference between the experimental and control groups in the average body weight, plasma creatinine level, systolic blood pressure, total 24 h urinary protein output, and glomerular filtration rate. Rats with menhaden oil had, however, statistically significant less aortic arteriosclerosis, myocardial damage, plasma cholesterol and triglyceride levels, and renal interstitial fibrosis than those with corn oil. The glomerular damage of the former as expressed by glomerulosclerosis index was numerically less than that of the latter. The data indicated that menhaden oil lessened the hypertensive damage to the renal and cardiovascular systems.

Animals↗
PubMed1991

[Antifungal and fungicidal activities of tea extract and catechin against Trichophyton].

We examined tea extract, (-) epigallocatechin gallate (EGCg) and theaflavin digallate (TF3) for their antifungal and fungicidal activities against Trichophyton mentagrophytes, T. rubrum, Candida albicans and Cryptococcus neoformans. Tea extract (2.5%) inhibited completely the growth of both T. mentagrophytes and T. rubrum. EGCg at 2.5 mg/ml failed to inhibit their growth, whereas TF3 at 0.5 mg/ml inhibited the growth. EGCg (1mg/ml) showed no fungicidal activity against Trichophyton. TF3 (1mg/ml) killed Trichophyton by a long time contact (72-96 hrs). Tea extract showed a fungicidal activity against Trichophyton in a dose- and contact time-dependent manner. It did not inhibit the growth of C. albicans, but at a high concentration, inhibited slightly the growth of C. neoformans. It had no fungicidal activity against C. albicans or C. neoformans.

Antifungal Agents↗
PubMed1991

[Antibacterial and bactericidal activities of tea extracts and catechins against methicillin resistant Staphylococcus aureus].

We examined tea extract, (-) epigallocatechin gallate (EGCg) and theaflavin digallate (TF3) for their antibacterial and bactericidal activities against methicillin resistant Staphylococcus aureus (MRSA) and food poisoning strains of S. aureus. Twenty percent tea extract (50 microliters), EGCg (63 micrograms) and TF3 (125 micrograms) added to one ml of culture medium each inhibited the growth of all strains of MRSA and food poisoning S. aureus tested. Tea extract showed also a bactericidal activity against MRSA even at the same concentration of as in ordinarily brewed tea. EGCg at a concentration of 250 micrograms/ml showed a bactericidal activity against MRSA but not against food poisoning S. aureus, but at 500 micrograms/ml reduced markedly the viable number within 48h. These results suggest that tea and catechin can be used as prophylactic agents against MRSA infection.

Biflavonoids↗
PubMed1991

Inhibition of rotavirus and enterovirus infections by tea extracts.

Epigallocatechin gallate from green tea and theaflavin digallate from black tea inhibited infections of cultured rhesus monkey kidney MA 104 cells with rotaviruses and enteroviruses. Their antiviral effects were maximally induced when directly added to virus, and their pre- and post-treatment of the cells produced much weak antiviral activity. Antiviral activity of the extracts therefore seems to be attributable to interference with virus adsorption.

Animals↗
PubMed1991

Effects of pirenzepine, AF-DX 116 and gallamine on the release of catecholamines from the dog adrenal gland in response to splanchnic nerve stimulation: interaction of M1 and M2 receptors with nicotinic receptors.

The present study was undertaken to examine how muscarinic antagonists modify the release of catecholamines evoked by splanchnic nerve stimulation (SNS) from the dog adrenal gland in vivo, in an attempt to elucidate whether muscarinic receptors play a functional role in catecholamine release. Output of epinephrine and norepinephrine was determined from adrenal venous blood by using high-performance liquid chromatography with electrochemical detection. SNS (1 and 3 Hz) produced increases in catecholamine output in a frequency-dependent manner. Intravenous administration of pirenzepine (10-100 micrograms/kg), a selective M1 receptor antagonist, or AF-DX 116 (30-300 micrograms/kg) and gallamine (0.3-3 mg/kg), selective M2 receptor antagonists, did not modify the SNS-induced increases in catecholamine output. C6 (hexamethonium) inhibited the SNS-induced increases in catecholamine output partially in a dose of 1 mg/kg and remarkably in a dose of 10 mg/kg. The combination of C6 (1 mg/kg) with pirenzepine (10 micrograms/kg), AF-DX 116 (30 micrograms/kg) or gallamine (0.3 mg/kg) inhibited the SNS-induced increases in catecholamine output more potently than C6 did by itself. The inhibition by C6 alone was about 50%, but that by each combination reached to about 80%. These results suggest that M2 receptors as well as M1 receptors play a facilitatory role in catecholamine release from the adrenal gland in response to SNS when the nicotinic receptor-mediated mechanism is partially inhibited.

Adrenal Glands↗
PubMed1990

A rapid microassay for hemolytic antibody--its application to immunotoxicological study.

A rapid microassay for hemolytic antibody using an automatic spectrophotometer was developed. This microassay was parallel to hemolytic plaque forming cell (PFC) assay most commonly used to detect antibody formation. The former had more advantages than the latter did. The data obtained using arsenic and some metallic compounds as immunomodifiers suggested that this microassay was suitable for the screening of immunomodifiers in immunotoxicological and immunopharmacological studies which deal with a large number of samples within limited time.

Animals↗
PubMed1990

[Antibacterial and anti-hemolysin activities of tea catechins and their structural relatives].

Among catechins tested, (-)epigallocatechin (EGC), (-)epicatechin gallate (ECg), (-) epigallocatechin gallate (EGCg) inhibited the growth of Staphylococcus aureus, Vibrio cholerae O1 classical Inaba 569B and El Tor Inaba V86. S. aureus was more sensitive than V. cholerae O1 to these compounds. EGCg showed also a bactericidal activity against V. cholerae O1 569B. Pyrogallol showed a stronger antibacterial activity against S. aureus and V. cholerae O1 than tannic and gallic acid. Rutin or caffein had no effect on them. ECg and EGCg showed the most potent anti-hemolysin activity against S. aureus alpha-toxin, Vibrio parahaemolyticus thermostable direct hemolysin (Vp-TDH) and cholera hemolysin. Among catechin relatives, only tannic acid had a potent anti-hemolysin activity against alpha-toxin. These results suggest that the catechol and pyrogallol groups are responsible for the antibacterial and bactericidal activities, while the conformation of catechins might play an important role in the anti-hemolysin activity.

Antitoxins↗
PubMed1990

[Relationship between the anti-hemolysin activity and the structure of catechins and theaflavins].

We examined the corresponding isomers of catechins and theaflavins for anti-hemolysin activities against Staphylococcus aureus alpha-toxin and Vibrio cholerae O1 hemolysin. Catechins and theaflavins showed anti-hemolysin activities in a dose-dependent manner. Among the catechins tested, (-)catechin gallate, (-)epicatechin gallate and (-)epigallocatechin gallate having galloyl groups in their molecules showed more potent anti-hemolysin activities against both toxins. On the other hand, free catechins, i. e. (-)catechin, (-)gallocatechin, (-) epicatechin and (-)epigallocatechin had low anti-hemolysin activities against alpha-toxin. Although (-)catechin or (-)gallocatechin had no effect on cholera hemolysin, (-) epicatechin and (-)epigallocatechin were slightly inhibitory. Among dextrocatechins, (+) epicatechin and (+)epigallocatechin proved to be more effective than (+)catechin and (+) gallocatechin. The anti-hemolysin activities of theaflavins against alpha-toxin and cholera hemolysin were dependent on the number of the galloyl group in their structure. These results suggest that the tertiary structure of the catechin or theaflavin and the active site of hemolysin, that affects the interaction between them, plays an important role in the anti-hemolysin activity.

Biflavonoids↗
PubMed1990

An experimental study on the healing process after excision of the articular disc of the mandible--effect of short-term intermaxillary fixation.

In the present study, intermaxillary fixation for a period of 1 or 2 weeks after excision of the articular disc was administered to maturing rats. After removal of the fixation, the animals were allowed unrestricted mandibular movement. Histological observations were made at the postoperative 3rd month in those rats which demonstrated normal occlusion. As a result, it was found that the normal articular disc did not regenerate. However, in the articular cavity, both connective tissue and articular disc-like structures were found. The major changes in the mandibular fossa were tylosis of the outer fibrous layer of the fossa and an accompanying shallowing tendency. The major changes in the condyle were tylosis and morphological deformation of the fibrous layer of the parietal region. The deformation was mainly manifested by a fan-shaped hypertrophy. In the cases in which neither connective tissue nor articular disc-like structures were present in the articular cavity, changes in the mandibular fossa and condyle were remarkable. The appearance of the articular disc-like structure was more frequent in cases with 2-week intermaxillary fixation than in those with 1-week fixation.

Animals↗
PubMed1990

Atherosclerosis and glomerulosclerosis in WHHL rabbits and obese Zucker rats.

The aorta and the kidney of 12 month old hyperlipidemic WHHL and obese Zucker rats, were examined morphologically. The WHHL developed severe and premature atherosclerosis but did not develop glomerulosclerosis. In contrast, the Zucker rats did not manifest atherosclerosis of the aorta, but developed glomerulosclerosis. These two animal models could be useful in understanding the roles of heterogeneous lipoprotein particles, genetic susceptibility, hemodynamic stress, and mesangial interactions with lipoproteins in the development of glomerulosclerosis.

Animals↗
PubMed1990

Prevention of 11-deoxycorticosterone-salt-induced glomerular hypertrophy and glomerulosclerosis by dietary phosphate binder.

The effects of dietary phosphate binder on deoxycorticosterone (DOC)-salt-hypertensive rats were examined. DOC-treated and non-DOC-treated rats were fed the diet either with or without phosphate binder, dihydroxyaluminum aminoacetate. All rats drank 1% NaCl. DOC-salt-treated rats without binder demonstrated marked glomerular hypertrophy, many globally sclerosed glomeruli, severe proteinuria, focal cardiac fibrosis, and splenomegaly. A significant reduction of glomerular hypertrophy, glomerulosclerosis, severity of proteinuria, splenomegaly, and the myocardial lesion took place when the DOC-salt-treated rats were given phosphate binder. The globally sclerosed glomeruli exhibited remarkable hypertrophy while structurally preserved glomeruli showed little evidence of enlargement. The plasma phosphate level was low in rats with dietary phosphate binder. In conclusion, the dietary phosphate binder ameliorated glomerular hypertrophy, glomerulosclerosis, proteinuria, myocardial fibrosis, and splenomegaly occurring in DOC-salt-treated rats. The data indicated that there was an association between glomerular hypertrophy and glomerulosclerosis in this model. The exact mechanisms of action of the phosphate binder, however, remain far from clear.

Aluminum Hydroxide↗
PubMed1989

A cytocidal tissue kallikrein isolated from mouse submandibular glands.

A cytocidal factor against mouse thymocytes was purified from the submandibular glands of female BALB/c mice using Sephadex G-50 gel filtration chromatography and reverse-phase HPLC. SDS-PAGE and amino acid sequence analysis revealed that the cytocidal factor was mouse glandular kallikrein (mGK)-6. mGK-6 showed an optimal enzyme activity at pH 10 and a cytocidal activity against thymocytes in a dose-dependent manner.

Amino Acid Sequence↗
PubMed1989

Biotinylation of human interleukin-2 for flow cytometry analysis of interleukin-2 receptors.

We designed a method to analyze receptors for interleukin-2 (IL-2R) using biotinylated IL-2 (b-IL-2). To optimize the condition of biotinylation of IL-2 for flow cytometry, the degree of biotinylation was controlled by monitoring the relative biotin contents in b-IL-2 with a newly developed ELISA. The b-IL-2 prepared by incubating 150 micrograms IL-2 in 150-300 micrograms/ml N-hydroxysuccinimidyl biotin retained biological activity and was appropriate for flow cytometry analysis. Positive fluorescence appeared in the IL-2R-bearing cell lines but not in those without IL-2R. This binding was inhibited by preincubation of the cells with unlabelled IL-2. The b-IL-2 bound to both low and high affinity IL-2Rs, but the binding to the latter was more intense. The advantage of this method is that expression of IL-2Rs of these two categories of affinity can be separately monitored.

Antibody Affinity↗
PubMed1989

A cytotoxic serine proteinase isolated from mouse submandibular gland.

We have isolated a novel cytotoxic factor from the submandibular glands of male BALB/c mice by Sephadex G-50 gel filtration chromatography and reverse-phase HPLC. The cytotoxic factor is a serine proteinase, which belongs to the mouse glandular kallikrein (mGK) family, with an Mr of approximately 27,000. The purified serine proteinase showed cytotoxic activity against mouse thymocytes in a dose-dependent manner, and a serine proteinase inhibitor, diisopropyl fluorophosphate, blocked its cytotoxic activity.

Animals↗
PubMed1989

[Antibacterial and bactericidal activities of Japanese green tea].

We found that extracts of Japanese green tea leaves inhibited the growth of various bacteria causing diarrheal diseases. All tea samples tested showed antibacterial activity against Staphylococcus aureus, S. epidermidis, Vibrio cholerae O1, V. cholerae non O1. V. parahaemolyticus, V. mimicus, Campylobacter jejuni and Plesiomonas shigelloides. None of the tea samples had any effect on the growth of V. fluvialis, Aeromonas sobria, A. hydrophila, Pseudomonas aeruginosa, Salmonella enteritidis, enteroinvasive Escherichia coli, enterohemorrhagic E. coli, enteropathogenic E. coli, enterotoxigenic E. coli, Enterobacter cloacae or Yersinia enterocolitica. Salmonella and Shigella showed susceptibilities different depending on the kind of Japanese green tea. Japanese green tea showed also bactericidal activity over S. aureus, V. parahaemolyticus and even enteropathogenic E. coli which was not sensitive when tested by cup method. The bactericidal activity was shown even at the drinking concentration in daily life.

Bacteria↗
PubMed1988

Involvement of antigen and I-J determinants in the induction of effector T suppressor cells by immune B cells.

Immune B cells induce effector T suppressor cells in vitro. The B cells act as antigen-presenting cells, and express both I-A and I-J determinants. Antigen and I-J determinants are required for the induction of suppressor T cells by immune B cells, but I-A determinants are not. These findings indicate that precursors of suppressor T cells appear to recognize antigen in the context of I-J determinants on the surface of immune B cells.

Animals↗
PubMed1988

The different roles of two distinct Fc gamma receptors on guinea pig macrophages in the phagocytosis of sensitized sheep erythrocytes.

The functional roles of two distinct types of Fc gamma receptors (Fc gamma 1/gamma 2R specific for both IgG1 and IgG2, and Fc gamma 2R specific for IgG2 alone) on the surface of guinea pig macrophages in the phagocytosis of sensitized sheep erythrocytes (EA) were investigated by the use of two Fab's of monoclonal anti-Fc gamma 1/gamma 2R and anti-Fc gamma 2R antibodies. The binding and subsequent ingestion of IgG1 antibody-sensitized erythrocytes (EA gamma 1) by macrophages were completely inhibited by anti-Fc gamma 1/gamma 2R Fab', indicating that the reactions are mediated only by Fc gamma 1/gamma 2R. On the other hand, the binding and subsequent ingestion of IgG2 antibody-sensitized erythrocytes (EA gamma 2) were substantially inhibited by anti-Fc gamma 2R Fab', but not by anti-Fc gamma 1/gamma 2R Fab'. The inhibitory activities of anti-Fc gamma 2R Fab' were dependent upon the amount of IgG2 antibody bound on erythrocytes; increasing the amount of bound IgG2 antibody from 0.15 to 0.91 micrograms/2 X 10(8) erythrocytes resulted in a decrease in the inhibition of binding of EA gamma 2 by anti-Fc gamma 2R Fab' from 50 to 0%, and also a decrease in the inhibition of ingestion of EA gamma 2 from 100 to 50%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗