Biomedical subjects

M Ozeki

Publications and source records attributed to M Ozeki.

At least 37 records · Page 2Linked to original sources

PubMed1997

Passive immunization against dental plaque formation in humans: effect of a mouth rinse containing egg yolk antibodies (IgY) specific to Streptococcus mutans.

Passive immunization involving the delivery of antibodies specific to pathogens of infectious diseases to the host has been an attractive approach to establish protective immunity against a variety of microbial pathogens, including Streptococcus mutans, which is the principal etiologic agent of dental caries in humans. The overall purpose of the present study was to determine the effectiveness of a mouth rinse containing antibodies to S. mutans in preventing the establishment of this bacterium in dental plaque of humans. The antibodies were derived from egg yolks obtained from hens immunized with whole cells of S. mutans grown in sucrose-containing medium. The immunoglobulin derived from the yolks (IgY) of immunized hens was characterized in vitro and in vivo in human volunteers. Cross-reactivity tests showed that immune IgY reacted with every serotype, except serotype b, which had lost its GTase activity, when the bacteria were cultured in sucrose-containing medium. Immune IgY inhibited S. mutans adherence to saliva-coated hydroxyapatite discs by 59.2%, while control IgY caused an inhibition of only 8.2%. In the short-term (4-hour) test using a mouth rinse containing 10% sucrose, immune IgY decreased the ratio of the percentage of S. mutans per total streptococci in saliva. In the long-term (7-day) test using a mouth rinse without sucrose, the ratio in saliva was not significantly reduced in the volunteers using the immune IgY due to the large standard deviation. However, comparing the ratios of the percentage of S. mutans per total streptococci in plaque of individual subjects, there was a tendency for a reduction of the ratios in the volunteers receiving the mouth rinse containing immune IgY. These results support the effectiveness of IgY with specificity to S. mutans grown in the presence of sucrose as an efficient method to control the colonization of mutans streptococci in the oral cavity of humans.

Antibodies, Bacterial↗

PubMed1997

Novel benzoxazole 2,4-thiazolidinediones as potent hypoglycemic agents. Synthesis and structure-activity relationships.

A new series of benzoxazole 2,4-thiazolidinediones was synthesized and evaluated for hypoglycemic activity in genetically obese and diabetic yellow KK mice. 2-Arylmethyl- and 2-(heteroarylmethyl)benzoxazole derivatives showed far more potent activity than known 2,4-thiazolidinedione derivatives such as ciglitazone, troglitazone and pioglitazone. A facile synthesis of benzoxazole 2,4-thiazolidinediones was also established using aminophenol 2,4-thiazolidinedione (11) as a key intermediate. Details of synthesis and structure-activity relationships for this series are described.

Animals↗

PubMed1997

Suppression of glucose absorption by extracts from the leaves of Gymnema inodorum.

Gymnema sylvestre (GS) is one of the Asclepiad strains that grows in South-east Asia. Their therapeutic effects for treating diabetes mellitus, rheumatic arthritis and gout have been well known for a long time. However, the problem is that GS suppresses sweetness and tastes bitter. For this study, we chose Gymnema inodorum (GI) instead of GS, since it has an advantage that it does not suppress sweetness nor is it bitter in taste. In this paper, effects of glucose availability of some saponin fractions (F-I to F-IV) extracted from GI leaves, which were obtained by high-performance liquid chromatography were studied on a high K(+)-induced contraction of guinea-pig intestinal smooth muscle, O2 consumption on guinea-pig ileum, glucose-evoked transmural potential difference (delta PD) of guinea-pig everted intestine and blood glucose level in glucose tolerance tests on rats. The extracts of GI leaves suppressed the intestinal smooth muscle contraction, decreased the O2 consumption, inhibited the glucose evoked-transmural potential, and prevented the blood glucose level. Our studies suggest that the component of GI inhibits the increase in the blood glucose level by interfering with the intestinal glucose absorption process.

Animals↗

PubMed1996

Sequence and product analyses of the four genes downstream from the fimbrilin gene (fimA) of the oral anaerobe Porphyromonas gingivalis.

The downstream DNA region of the fimbrilin gene (fimA), which encodes the major subunit protein of Porphyromonas gingivalis fimbriae, was fully sequenced. Gene products, expressed from this region in Escherichia coli, were purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their partial amino acid sequences were determined to verify open reading frames (ORFs) found in the region by DNA sequencing. Four ORFs, designated ORF1, ORF2, ORF3 and ORF4, were found in the 5.8-kb PstI fragment downstream from fimA, which was previously cloned and partially characterized by Yoshimura, Takahashi, Hibi, Takasawa, Kato, and Dickinson (Infect. Immun. 61: 5181-5189, 1993). The direction of transcription of all the ORFs was the same as that of fimA. The 50 and 80 kDa encoded proteins, ORF2 and ORF3, respectively, have been reported to be minor components associated with fimbriae. The 15 and 19 kDa proteins, ORF1 and ORF4, respectively, have been expressed in E. coli but not identified in P. gingivalis. However, all the gene products of the ORFs, expressed in E. coli, appeared to contain intact signal peptides based on their N-terminal amino acid sequences.

Amino Acid Sequence↗

PubMed1996

Purification and characterization of a lectin from Amaranthus hypochondriacus var. Mexico seeds.

A lectin from Amaranthus hypochondriacus var. Mexico (AHML) was purified by affinity chromatography using asialofetuin-Sepharose 4B. AHML is specific for N-acetyl-D-galactosamine as are the other Amaranthus lectins. AHML has no carbohydrate moiety and requires no metal ion for the hemagglutination activity. The pI of AHML is 6.8. AHML has a native molecular mass of 45.0 kDa and is composed of homo-subunits having molecular masses of 36.8 kDa.

Amino Acids↗

PubMed1996

Characterization of a lectin from the leaves of great northern bean, Phaseolus vulgaris L.

A novel lectin (GNLL) was isolated from the leaves of the Great Northern bean, Phaseolus vulgaris. GNLL was purified by affinity chromatography on ovomucoid-Sepharose 4B. GNLL had a molecular mass of 135 kDa on gel filtration and gave two bands on SDS-polyacrylamide gel electrophoresis (PAGE)(band A of 34.0 kDa and band B of 34.2 kDa). Binding assay of horseradish peroxidase (HRP)-glycoproteins to the bands electroblotted onto polyvinylidene difluoride (PVDF) membrane showed that both bands could bind to complex-type N-linked oligosaccharide chains in glycoproteins. The N-terminal amino acid sequences of both bands were identical through the 10 residues and identical to that of alpha-subunit of a pod lectin (pod-alpha-subunit) from the same bean. On the other hand, band B cross-reacted with monoclonal antibody against a seed lectin from the same bean, but band A did not.

Amino Acid Sequence↗

PubMed1996

Langerhans cells in mice with severe combined immunodeficiency (SCID).

The existence of Langerhans cells in the stratified squamous epithelium of severely combined immunodeficient (SCID) mice was studied by enzyme histochemistry, immunohistochemistry and electron microscopy. Considerable numbers of ATPase-positive Langerhans cell were observed in the epidermis (ear and hind limb) as well as in the stratified squamous mucosal epithelium (forestomach and tongue) of SCID mice. The cells also expressed Ia antigen. This indicates that, in spite of the lack of functional T and B lymphocytes, the antigen-presenting function of Langerhans cell was retained in SCID mice. In the epidermis, frequency of Ia expressing Langerhans cells was low, but in the forestomach epithelium, 90% of Langerhans cells had strong Ia positivity. In the forestomach epithelium of SCID mice, the regulation of Langerhans cell maturation was affected differently from the epidermis. As with normal mice, the occurrence of Langerhans cell in female SCID mice was higher than in males; hormonal immuno-regulations may be normal in SCID mice. Under electron microscopy, many Birbeck granules were observed in epidermal Langerhans cells but few in those of the mucosal epithelium. In SCID mice, Langerhans cell exists constitutively in the epidermis and mucosal epithelium, where the cell may function in a defense system independent from T and B lymphocytes.

Adenosine Triphosphatases↗

PubMed1996

Inhibitory effect of roxithromycin on biofilm formation of Pseudomonas aeruginosa.

Biofilm formed by bacteria has recently has been shown to be involved in making infectious diseases intractable. We indirectly measured and evaluated the inhibitory effect of roxithromycin (RXM) on biofilm formation on the inside of a plastic test tube by determining the number of living bacteria in the biofilm. As a result, RXM was found to inhibit biofilm formation even though it does not have antimicrobial activity against Pseudomonas aeruginosa. In addition, this inhibitory effect on biofilm formation was observed at in vivo concentrations which are possible in clinical use of RXM. Thus, there is a possibility that RXM is effective against infectious otolaryngological diseases when biofilm formation is likely to be pathologically involved, even if the detected bacteria are not sensitive to the drug.

Anti-Bacterial Agents↗

PubMed1993

Effect of the rice bran-derived phytosterol cycloartenol ferulic acid ester on the central nervous system.

In order to investigate the effect of cycloartenol ferulic acid ester (CFE, CAS 21238-33-5), a component of gamma-oryzanol which is a phytosterol derived from rice bran, on the central nervous system, a variety of pharmacological tests were performed. It was shown that CFE had a suppressant effect on the central nervous system, but its properties were different from those of existing major and minor tranquilizers. In addition, its efficacy in several models of cerebral dysfunction was demonstrated. Since any clear effects could not be obtained under the treatments with gamma-oryzanol, CFE seems to be more useful than gamma-oryzanol. Thus the results of this study suggest that CFE may serve as a new plant-derived cerebral activator possessing a wide range of pharmacological actions.

Amnesia↗

PubMed1992

Molecular cloning and expression of a major surface protein (the 75-kDa protein) of Porphyromonas (Bacteroides) gingivalis in Escherichia coli.

A major immunodominant surface protein (the 75-kDa protein) of Porphyromonas (Bacteroides) gingivalis 381 has been purified and its amino-terminal amino acid sequence has been determined. Using oligonucleotide probes corresponding to the sequence, we identified a recombinant plasmid clone carrying a single 4.2-kb BamHI fragment from pUC19 libraries of P. gingivalis. The BamHI fragment transferred to the bacteriophage T7 RNA polymerase/promoter expression vector system produced a slightly larger (77-kDa) protein, a precursor form, immunoreactive to the antibody against the 75-kDa protein, suggesting that the cloned DNA fragment probably carried an entire gene for the 75-kDa protein. Genomic Southern analysis revealed a single copy of the 75-kDa protein gene per genome among all P. gingivalis strains tested, and that no homologous genes are present in other black-pigmented Bacteroides species. These observations suggest that the 75-kDa protein gene may be useful as a specific DNA probe to classify or to detect this organism.

Amino Acid Sequence↗

PubMed1992

Invasion of Streptococcus mutans, Streptococcus intermedius and Propionibacterium acnes into the teeth of gnotobiotic rats.

Germ-free rats, fed a modified cariogenic diet 2000 with a reduced sucrose content of 25%, were inoculated with a strain of Streptococcus mutans, Streptococcus intermedius or Propionibacterium acnes, respectively. After 100 days on the diet, the rats were sacrificed. Microscopic examination of stained decalcified tooth sections revealed marked destruction of the outer zones of the dentin infected with S. mutans. The destruction was closely associated with the formation of glucan-mediated large aggregates of S. mutans. The aggregates, however, were rarely formed in the deep zones of the infected dentin. Inoculation with S. intermedius and P. acnes had little effect on the microscopic outline of the decalcified tooth sections. However, the staining behavior of the sections with Mallory's method, Alcian blue-PAS and silver was like that of the tooth sections infected with S. mutans, even in the central and inner zones of the dentin. The histochemical alterations of the deep zones of the dentin induced by the three infected bacteria appeared to be due to their proteolytic rather than to their acidogenic activities.

Animals↗

PubMed1992

Molecular stability of chicken and rabbit immunoglobulin G.

Molecular stability of chicken egg yolk immunoglobulin G (IgY) and that of rabbit IgG were compared by measuring antibody activities and conformational changes. Stability of rabbit IgG to acid denaturation was much higher than that of IgY. Conformation of the IgY molecule was readily changed in acidic conditions, resulting in a rapid loss of antibody activity. Much less stable natures of IgY to heat-treatment and guanidine-HCl denaturation than rabbit IgG were also observed. Differences in the structure between the two immunoglobulins that might participate in their different stability were inferred from their amino acid sequence data. Importance of the intramolecular disulfide linkage in the rabbit light chain and some other structural differences were suggested.

Animals↗

PubMed1991

[Effects of CN-100 on the functions of rat polymorphonuclear leukocytes].

We studied the effects of CN-100 on the functions of rat polymorphonuclear leukocytes (PMN) in vitro. CN-100 showed the inhibitory effects of superoxide production and luminol dependent chemiluminescence induced by opsonized zymosan (OZ) or N-formyl-methionyl-leucyl-phenylalanine (FMLP) in PMN, and its inhibitory activity was almost equipotent to that of indomethacin and more than that of pranoprofen. Preincubation of cytochalasin E-treated PMN with CN-100, indomethacin and pranoprofen resulted in dose-dependent inhibition of lysosomal enzyme release elicited by OZ or FMLP, but pranoprofen was less potent than CN-100 and indomethacin. CN-100 and indomethacin inhibited the increase of intracellular calcium in FuraII loaded PMN stimulated by FMLP. The inhibitions by both agents were reversible. These findings indicated that the reversible interaction between CN-100 and PMN membrane inhibit signal transduction starting from intracellular calcium mobilization in PMN and suppress many PMN's functions. These results suggest that CN-100 has an inhibitory activity on PMN function which is as potent as that of indomethacin.

Animals↗

PubMed1991

Effects of the new anti-ulcer drug nizatidine on prostaglandins in the rat gastric mucosa.

The effects of nizatidine (N-[2-[[[2-[(dimethylamino)methyl]- 4-thiazolyl]methyl]thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine , CAS 76963-41-2), a new histamine H2-receptor antagonist, on the content of prostaglandins (PGs) in the rat gastric mucosa at doses that inhibit basal gastric acid secretion were compared with those of two other histamine H2-receptor antagonists, cimetidine and ranitidine. Nizatidine did not inhibit basal gastric acid secretion at a dose of 0.4 mg/kg but showed dose-dependent inhibition at doses of 10, 30, and 100 mg/kg. This drug had no effects on the content of PG in the gastric mucosa when subcutaneously administered at doses of 0.4, 10, 30 and 100 mg/kg once daily for 5 days. Cimetidine and ranitidine administered at doses that markedly inhibit basal gastric acid secretion (250 and 100 mg/kg/d, respectively) had no effects on the content of PG in the gastric mucosa. On the other hand, nizatidine, cimetidine, or ranitidine at concentrations of 1-100 mumols/l did not inhibit in vitro PGE2 synthesis using sheep seminal vesicle microsomes. These results suggest that nizatidine did not affect in vitro PGE2 synthesis and even doses that markedly inhibit gastric acid secretion had no effects on the content of PGs in the gastric mucosa.

6-Ketoprostaglandin F1 alpha↗

PubMed1990

Bacteriological examination of fissure plaques from seriously mentally retarded adults.

The microfloras of fissure plaque samples removed from a total of 23 seriously mentally retarded adults, resident in two institutions, were examined and compared with the fissure microfloras found in 17 control subjects who were employees in both institutions. The samples were collected from both an intact fissure and a fissure with brown-stained defective enamel surface of the premolars of the lower jaw. Mutans streptococci, selected with MSB medium, were recovered from only one of the defective fissures of 13 patients who became retarded younger than 2 years of age, whereas 14 defective fissures of 17 controls harbored mutans streptococci. Four of 8 patients who became retarded older than 3 years of age harbored mutans streptococci. Lactobacilli were infrequently recovered from both patients and controls. The results are discussed in terms of the microbiological aspect of caries development in adults who became mentally retarded when young.

Adult↗

PubMed1990

[Interaction of CN-100, a novel non-steroidal anti-inflammatory drug, on biopolymers].

Interaction of CN-100, a novel non-steroidal anti-inflammatory drug, with biopolymers were investigated. In collagen induced rat platelet aggregation, the inhibitory effect of CN-100 was almost equipotent as indomethacin (IM) but less potent than that of pranoprofen (PP). The effect of CN-100 on rat platelet aggregation induced by arachidonic acid (AA) was less potent than that of IM and PP. CN-100 inhibited rat platelet functions, serotonin release and malondialdehyde formation, induced by collagen more potently than those induced by AA. In heat-induced rat erythrocyte lysis and Ca2(+)-induced liposome aggregation, the inhibitory effect of CN-100 was less potent than IM but more than those of PP. CN-100 was inhibited with heat denaturation of BSA, and the effect was more potent than IM and PP. The metachromagy based on the binding of an azodye, HABA, to BSA was potentiated weakly by CN-100, but IM had no effect on it. CN-100 and IM increased the fluorescence of the binding of dansyl amide (site I probe) to BSA. These results support that there is considerable interaction between CN-100 and membrane protein, and this effect influences the membrane to increase its stability.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1990

Serogrouping of oral Streptococcus intermedius.

Employing twenty fresh oral isolates of Streptococcus intermedius, studies were carried out to characterize serological relations among the isolates and also between the isolates and the strains of bacterial species closely related to S. intermedius. The Rantz-Randall extracts from the cells were used as antigens. The anti-rabbit serum raised against S. intermedius ATCC 27335T reacted with the cell extracts from only three strains of the isolates, which were designated serogroup I strains. The other isolates were classified into four serogroups, I, III, IV, and V, which specifically reacted with the cell extracts from the homologous serogroup strains. However, the serogroup II antiserum formed in immunodiffusion a common precipitin line between the extracts from the cells of serogroups II and I. The serogroups I, III, IV, and V antisera reacted with none of the extracts from the bacterial cells closely related to S. intermedius, which included Streptococcus anginosus ATCC 33397T, Streptococcus constellatus ATCC 27823T, three NCTC strains of "Streptococcus milleri," and three ATCC strains of Streptococcus MG. The precipitin line formed by the homologous reaction of the serogroup II antiserum was found to be a reaction of identity with that formed by the extract from "S. milleri" NCTC 10708. Conversely, the antiserum against NCTC 10708 strain did not react with the cell extracts of serogroup II.

Animals↗

PubMed1989

Cytotoxicity against various cell lines of lipopolysaccharides purified from Bacteroides, Fusobacterium, and Veillonella isolated from infected root canals.

The cytotoxicity against two mesenchymal cell lines, L-929 and WI-38, and two epithelial cell lines, KB and HeLa S-3, of lipopolysaccharide (LPS) purified from strains of Bacteroides gingivalis, Fusobacterium nucleatum, and Veillonella parvula isolated from infected root canals was investigated. The inhibition of cell growth by these LPS's was considerable for mesenchymal cell lines, but mild for epithelial cell lines. The cytotoxic effect of F. nucleatum LPS was the greatest and that of B. gingivalis LPS was the least.

Bacteroides↗