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T Koga

Publications and source records attributed to T Koga.

At least 667 records · Page 37Linked to original sources
PubMed1984

A possible mechanism for the cellular coaggregation between Actinomyces viscosus ATCC 19246 and Streptococcus sanguis ATCC 10557.

The cells of Actinomyces viscosus ATCC 19246 (Av19246) and Streptococcus sanguis ATCC 10557 (Ss10557) coaggregated immediately after mixing in 40 mM-Tris/HCl buffer. Optimal conditions were pH 7.5 in the presence of Ca2+ at 0.1 mM or higher. Na2 EDTA and its analogues, Na2MgEDTA and Na2MnEDTA at 7.5 mM inhibited the coaggregation. Trypsin and heat treatment impaired the reactive site on Av19246 cells, but not on Ss10557 cells. The coaggregates, once formed, dissociated gradually during extended incubation at 37 degrees C; this was prevented by addition of sufficient Ca2+. The disaggregation appears to be a spontaneous denaturation of the proteinaceous reactive site on Av19246 cell surface. Thus, the coaggregation involves the interaction of a lectin-like substance on the surface of Av19246 with a carbohydrate site on Ss10557. Native Ss10557 cell walls possessed reactivity with Av19246 cells but 5% (w/v) TCA-extracted cell wall residues did not. A carbohydrate moiety extracted from Ss10557 exhibited a high potency in blocking coaggregation, and coaggregates were dissociated upon addition of the carbohydrate. Lactose, galactose and N-acetyl-D-galactosamine (the latter two are major constituents of the antigen extract) also significantly inhibited the coaggregation, but the other antigen components, glucose and rhamnose, did not. Relative inhibitory activity, expressed as molar potency, of carbohydrate antigen, lactose, galactose and N-acetyl-D-galactosamine respectively, was approximately 26 X 10(3):16:4:1. Ss10557 cells and cell walls reacted only with a Ricinus communis (castor bean) agglutinin-120 but not with Glycine max (soybean) agglutinin, Arachis hypogaea (peanut) agglutinin or Phaseolus vulgaris agglutinin (phytohaemagglutinin).(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces↗
PubMed1984

Immunochemical characteristics of Streptococcus mutans serotype h carbohydrate antigen.

Serotype h carbohydrate antigen was prepared from cell walls of Streptococcus mutans strain MFe28 of monkey origin. The h antigen was extracted from the cell walls with 5% trichloracetic acid at 4 C, and purified by DEAE-Sephadex A-25 ion exchange chromatography followed by Sephacryl S-300 gel filtration. The purified antigen was composed of galactose (75%), glucose (16%), and rhamnose (3%). Although the antiserum against whole cells of S. mutans MFe28 gave a strong cross reaction with serotype d S. mutans, serotype h-specific antiserum could be obtained by adequate adsorption. The precipitin reactions and hapten inhibition test using serotype h-specific antiserum showed that galactose, glucose, and their derivative sugars were markedly potent inhibitors. It was concluded that the serotype h antigen is immunologically distinguishable from the known serotypes of S. mutans, although it is closely related to serotype d antigen of S. mutans.

Antigens, Bacterial↗
PubMed1984

Ability of various oral bacteria to bind human plasma fibronectin.

The present study describes the ability of various oral bacteria to bind human plasma fibronectin (PFN). Avid binding of 125I-PFN was found for Streptococcus mutans (serotypes a to h), Streptococcus sanguis, group A Streptococcus pyogenes and Staphylococcus aureus, while other gram-positive bacterial species tested demonstrated only weak or negligible PFN binding ability. Two gram-negative bacterial species, Bacteroides gingivalis and Escherichia coli, did not significantly bind PFN. 125I-PFN binding to S. mutans 6715 cells was decreased by pretreatment with unlabeled PFN, and the radiolabeled PFN bound to the cell surface was released on addition of unlabeled PFN. Strong inhibition of 125I-PFN binding to S. mutans 6715 cells was obtained by protease pretreatment, while partial inhibition was also observed following treatment with acid, alkali, lipase, and monoclonal anti-polyglycerophosphate. These results suggest that PFN binding to S. mutans cells is reversible and that PFN receptors on the cell surface appear to be heat-stable multiple proteins.

Bacteria↗
PubMed1984

Partial characterization of thymocyte-activating factor derived from MDP-stimulated guinea pig fibroblasts.

The activity of fibroblast-derived thymocyte activating factor (FTAF) of the guinea pig was measured, and the factor was partially characterized. The FTAF activity was heat labile, and destroyed by treatment with trypsin, chymotrypsin, and Streptomyces griseus protease, suggesting the protein nature of FTAF. FTAF bound to DEAE-Sepharose CL-6B in Tris-HCl buffer at pH 8.0, and was eluted with 0.1-0.2 M NaCl. FTAF was absorbed with Blue Sepharose CL-6B. The factor bound to a hydroxylapatite column in 10 mM phosphate buffer and was eluted in two major fractions, one fraction with 40 mM phosphate buffer, the other with 70-110 mM phosphate buffer. Finally, FTAF did not have as much effect on the proliferation of lymph node T cells as T-cell-activating monokines which exhibited marked stimulating effects on both T lymphocytes and thymocytes.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1984

Clinical isolates of Streptococcus mutans serotype c with altered colony morphology due to fructan synthesis.

Streptococcus mutans MT6801 , MT6861 , and MT6879 , which form large mucoid colonies on mitis salivarius agar, were isolated from a mother and her two daughters. These isolates were identified as serotype c by immunodiffusion with serotype-specific antisera. The large colonies formed on sucrose-containing agar were found to contain water-soluble fructan . The cell-free fructosyltransferase ( FTase ) activity of the strains which formed large colonies was five to eight times higher than that of serotype c S. mutans which produced small, rough colonies typical of this serotype. Furthermore, greater quantities of fructan were synthesized from sucrose by growing cells of MT6801 when compared with MT8148 , a typical serotype c S. mutans. Glucosyltransferase and FTase could be isolated by chromatofocusing from culture supernatants of MT6801 and MT8148 . The FTase activity of both strains was eluted at pH 4.5, and glucosyltransferase was released by elution with an NaCl linear gradient. The eluted FTase activity of MT6801 was significantly higher than that of MT8148 . Strains MT6861 and MT6879 were also found to possess a similar property in terms of FTase activity. These results suggest that formation of large mucoid colonies by these strains is a consequence of high FTase activity.

Adult↗
PubMed1984

Classification of Vibrio bacteriophages.

85 Vibrio phages, 84 of them tailed and 1 filamentous, were surveyed. The tailed phages belonged to six basic morphotypes and to the Myoviridae, Siphoviridae, or Podoviridae families. 63 phages were classified into 18 species. The filamentous phage is a member of the Inovirus genus of the Inoviridae family. Vibrio phages are very heterogenous and include some morphologically interesting viruses. Several Vibrio phages closely resemble phages of other gram-negative bacteria, possibly indicating phylogenetic relationships between their hosts.

Bacteriophages↗
PubMed1984

Virulence factors of Streptococcus mutans and dental caries prevention.

Streptococcus mutans possesses the abilities to adhere to pellicle-coated tooth surfaces and to form acids - two characteristics associated with the cariogenicity of this micro-organism. De novo synthesis of insoluble glucan by S. mutans glucosyltransferase from sucrose is essential in the adherence process. Therefore, agents which interfere with the adherence ability of S. mutans would be useful for controlling dental caries. In the present report, we have summarized our recent findings concerning virulence factors of S. mutans and means for prevention of S. mutans-induced dental caries.

Adhesiveness↗
PubMed1984

[Fundamental and clinical studies of sulbactam/cefoperazone in the pediatric field].

To 6 cases of children in 2 groups of 3 each, newly developed sulbactam/cefoperazone (SBT/CPZ) was given at 20 and 40 mg/kg by intravenous bolus injection, respectively, and the serum and urinary concentrations and recoveries of SBT and CPZ were determined. To 1 case of purulent meningitis, this drug was given at 40 mg/kg by intravenous bolus injection, and the cerebrospinal fluid and serum concentrations of SBT and CPZ were determined. Susceptibility tests to SBT/CPZ and CPZ of total 289 strains were conducted; Gram-positive cocci tested consisted of 26 S. aureus strains, 20 S. pyogenes strains and 21 S. pneumoniae strains, and Gram-negative bacilli consisted of 24 H. influenzae strains, 22 E. coli strains, 26 K. pneumoniae strains, 24 E. cloacae strains, 21 E. aerogenes strains, 19 Citrobacter sp. strains, 20 S. marcescens strains, 23 P. mirabilis strains, 23 indole-positive Proteus sp. strains and 20 P. aeruginosa strains. SBT/CPZ was given to total 43 cases at a mean daily dosage of 80.4 mg/kg, in 3 or 4 divided doses (6 cases in 3 and 37 cases in 4), 1 case receiving the drug by drip infusion over 30 minutes (in 3 divided doses) and all the other 42 cases by intravenous bolus injection, for 7 days on an average. They consisted of 2 cases of tonsillitis, 1 case of otitis media, 1 case of otitis media associated with mastoiditis, 30 cases of pneumonia, 1 case of suspected septicemia, 1 case of purulent meningitis, 5 cases of urinary tract infection, 1 case of purulent lymphadenitis and 1 case of submaxillaritis. And the clinical and bacteriological effects were evaluated. Also, side reactions and laboratory examinations for abnormal values due to administration of this drug were made on 47 cases including 4 drop-outs. The following results were obtained: After administration of this drug to 2 groups of 3 children each at 20 and 40 mg/kg by intravenous bolus injection, mean serum concentrations of both SBT and CPZ reached the peaks in 5 minutes; SBT levels were 60.9 and 124.7 micrograms/ml for the 2 groups and CPZ levels were 105.0 and 214.1 micrograms/ml, respectively. In either group, CPZ levels were 1.7 times as high as SBT levels, and there was observed a dose-response in both. In the 20 mg/kg group, mean half-lives of SBT and CPZ were 0.96 and 1.24 hours, respectively, and in the 40 mg/kg group, they were 1.01 and 1.32 hours, CPZ values tending to be longer.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Fundamental and clinical evaluation of ceftriaxone in the pediatric field].

Fundamental and clinical evaluation on ceftriaxone (Ro 13-9904, CTRX), a newly-developed injectable cephem antibiotic was performed as follows. The serum and urine concentrations of CTRX as well as the urinary recovery rate were determined in 7 children at 3 different dose levels; 3 cases administered with 10 mg/kg, 3 with 20 mg/kg and 1 with 48 mg/kg by one shot intravenous injection. The concentration in the cerebrospinal fluid was determined in 1 case of purulent meningitis associated with bacteremia, administered by one shot intravenous injection with 47.6 mg/kg. CTRX was also examined in its clinical and bacteriological efficacies by one shot intravenous injection for 8 days on average in a mean daily dose of 46.5 mg/kg, divided into twice a day in 31 cases, 3 times in 1 case, and 4 times changed from twice in 1 case; in a total of 33 children consisting of 3 with tonsillitis, 1 with chronic bronchitis, 20 with pneumonia, 2 with purulent meningitis associated with bacteremia, 3 with urinary tract infections, 1 with osteomyelitis associated with phlegmon, 3 with purulent lymphadenitis. The adverse reactions and laboratory test values were examined in a total of 40 cases, i.e., the above-mentioned 33 cases plus the 7 drop-out cases in which the clinical efficacy could not be evaluated. The results were as follows. The serum levels of CTRX in 7 cases consisting of 3 administered with 10 mg/kg, 3 with 20 mg/kg and 1 with 48 mg/kg reached their peaks 5 minutes after one shot intravenous injection and the mean values of them were 93.6 mcg/ml, 143.0 mcg/ml and 558.0 mcg/ml, respectively, indicating the existence of a dose-response among these groups, while the half-life times were 4.41, 5.86 and 4.09 hours. Among the 7 cases examined in the urinary levels as well as the serum levels, the 3 cases administered with 10 mg/kg reached the mean peak of 334.0 mcg/ml 2 to 4 hours after administration, while another 3 cases administered with 20 mg/kg showed peaks of 793.0, 522.0 and 536.0 mcg/ml, respectively, 2 to 4 hours, 4 to 6 hours and 6 to 12 hours after injection; this dispersion being partly because of that the urine specimen was unable to be collected regularly every hour in this dose group. In the case administered with 48 mg/kg, urinary level reached the highest value of 6,100.0 mcg/ml from 0 to 2 hours.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1984

[Fundamental and clinical studies of ceftazidime in the pediatric field].

Ceftazidime ( CAZ ), a newly-developed parenteral cephem antibiotic, was administered to 8 children; by one shot intravenous (i.v.) injection in the doses of 20 and 40 mg/kg each to 2 children, and by 30 minutes' i.v. drip infusion in the doses of 10 and 20 mg/kg each to 2 children, and the serum levels, urinary levels and recovery rates were determined. CAZ was also administered to 2 patients with purulent meningitis, one complicated with subdural abscess and the other with bacteremia, in the doses of 19.2 and 50.7 mg/kg, respectively, by one shot i.v. injection, and the CSF level of CAZ was determined. In addition, CAZ was administered to 2 children with acute bronchitis, 1 with chronic bronchitis, 37 with pneumonia, 3 with pleuropneumonia, 1 each for purulent meningitis, purulent meningitis accompanied with subdural abscess and purulent meningitis with bacteremia, 5 with urinary tract infections and 3 with purulent lymphadenitis (total 54 children), in the mean dose of 85.8 mg/kg/day mostly in 4 divided doses by one shot i.v. injection for 9 days on the average, and clinical effectiveness and bacteriological response were evaluated in these cases, and adverse events and abnormal laboratory findings were examined in the 66 cases which included 12 drop-out cases. 1. After the administration of CAZ to 4 children; 20 and 40 mg/kg each to 2 children, by one shot i.v. injection, the mean serum levels got to the peak of 115.8 and 199.5 mcg/ml, respectively, at 5 minutes. The results were good, showing dose response. The mean half-lives were 1.48 and 1.37 hours, respectively. After the administration of 10 and 20 mg/kg of CAZ each to 2 children by 30 minutes' i.v. drip infusion, the mean serum levels got to the peak of 58.5 and 80.0 mcg/ml, respectively, on completion of the administration, showing dose response. The mean half-lives were 1.06 hours in the former 2 cases, and 1.38 and 3.26 hours, respectively, in the latter 2 cases. The reason for the prolongation observed in 1 case was not clear. 2. In the above mentioned each 2 cases receiving one i.v. injection, the mean urinary levels got to the peak of 4,240 and 4,445 mcg/ml, respectively, at 0-2 hours after the administration , and the urinary recovery rates during the first 6 hours were high, 95.7% and 99.5%, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Clinical trials of cefmetazole for pneumonia and pyothorax caused by Staphylococcus aureus resistant to cefazolin].

Cefmetazole (CMZ), an antibiotic agent of the cephamycin group, is resistant to beta-lactamase and has a broad antibacterial spectrum covering Gram-positive cocci and Gram-negative bacilli. However, it has not been indicated for Gram-positive cocci. We examined its clinical, bacteriological and side effects in 2 infants with pneumonia and 2 with pyothorax, which had been suggested to be caused by CEZ-resistant and CMZ-sensitive Staphylococcus aureus or other inflammatory organisms by a disc sensitivity test, for 2 years and 3 months from January, 1981 to March, 1983. The patients aged 1 to 22 months, and a mean daily dose of 108 to 115 mg/kg was divided into 2 to 4 equal doses and injected into the vein at one shot for a mean fo 19 days. The following results were obtained: The clinical effect of CMZ was evaluated to be good in 1 and fair in 1 of 2 infants with pneumonia, and excellent in 1 and good in 1 of 2 with pyothorax. Bacteriologically, S. aureus was removed in an infant with pneumonia and in 2 with pyothorax. Bacteriological test was not conducted in the remaining 1 with pneumonia. No side effects were found in any cases. Eosinophilia appeared as an abnormal clinical test value in a case, but the number of eosinophils became normal after termination of the medication. As mentioned above, CMZ manifested an excellent clinical effect in infants with pneumonia or pyothorax caused by S. aureus although the number of the patients was small. From the results the antibiotic agent can be expected to be effective in these disease.

Age Factors↗
PubMed1984

[Ultrasonic diagnosis of tumors of the spleen].

Neoplasms of the spleen, either primary or secondary, are rare, and knowledge of them is insufficient. Actually, the spleen had been a difficult organ clinically to assess until the ultrasonic technique was introduced for medical diagnostic purposes. Nowadays, one can easily determine splenic size by using one of the largest cross sectional area of several ultrasonic scans taken parallel to the IXth ribs). Ultrasonic appearance of the spleens in the tomograms taken by our method is classified into three basic patterns. Splenotomograms of our own cases with diffuse and localized splenic tumors were shown in this study. Ultrasonic scanning of the spleen is a non-invasive and valuable diagnostic technique for estimation of its configuration and size, and for detection and some degree of tissue characterization of space occupying lesions. However, further extensive investigation is needed for more accurate tissue characterization of the splenic lesions.

Aged↗
PubMed1984

Specificity of anti-type II collagen antibody response in rats.

Specificity of the rat antibody against type II collagen was investigated using rat, bovine and human type II collagen preparations. PVG/c rats showed the highest antibody level in assays with autologous rat type II collagen than with heterologous (bovine or human) type II collagen even when immunized with heterologous one. On the other hand, the rat exhibited significantly low antibody response when they were immunized with autologous type II collagen. The results indicate that rats develop strong antibody response against self type II collagen when immunized with heterologous collagen and this unique specificity of anti-type II collagen antibody response suggests that autoimmunity is involved in the pathogenesis of collagen-induced arthritis in rats.

Animals↗