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T Koga

Publications and source records attributed to T Koga.

At least 685 records · Page 38Linked to original sources
PubMed1983

Stimulation of Ca2+ efflux by N-formyl chemotactic peptides in guinea-pig peritoneal macrophages.

Effects of N-formyl chemotactic peptides on the Ca2+ influx and efflux were investigated in guinea-pig peritoneal macrophages using an isotope tracer. fMet-Leu-Phe did not enhance the influx of 45Ca2+ into macrophages, whereas it stimulated the efflux of 45Ca2+ from macrophages at concentrations ranging from 10(-10) M to 10(-7) M. fMet-Met-Met and fMet-Leu also stimulated the 45Ca2+ efflux, albeit at much higher concentrations, while there was no stimulation with fMet. The mitochondrial inhibitors, oligomycin and NaN3, did not modify the 45Ca2+ efflux induced by the chemoattractants, yet they did induce the release of 45Ca2+ from the mitochondria. On the other hand, higher concentrations of the calmodulin antagonists, chlorpromazine and trifluoperazine, induced the release of 45Ca2+ from the NaN3-insensitive Ca2+ store site and mimicked the enhancement of the 45Ca2+ efflux by N-formyl chemotactic peptides. Thus, N-formyl chemotactic peptides appear to increase the levels of intracellular free Ca2+ in guinea-pig peritoneal macrophages, probably by inducing the release of Ca2+ from the NaN3-insensitive Ca2+ store site.

Animals↗
PubMed1983

Stimulating effect of MDP and its adjuvant-active analogues on guinea pig fibroblasts for the production of thymocyte-activating factor.

Synthetic muramyl dipeptide (MDP) could stimulate skin fibroblasts of the guinea pig to produce thymocyte-activating factor, which augments the proliferative response of thymocytes to phytohemagglutinin (PHA). Adjuvant-active analogues of MDP also stimulated fibroblasts to produce the factor, whereas adjuvant-inactive analogues failed to do so. Thus a marked parallelism was found between adjuvant activity of these compounds and the stimulating effect on fibroblasts. Thymocyte-activating factor derived from MDP-stimulated fibroblasts was found in the fraction of mol wt 30,000-60,000 by gel filtration on a Sephacryl S-200 column. Furthermore, this factor did not exhibit T cell growth factor activity.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1983

Degradation of the microbial and salivary components participating in human dental plaque formation by proteases elaborated by plaque bacteria.

Twenty-eight strains of facultative, Gram-positive, sporulating bacilli which produce caseinolytic enzymes were isolated from human early dental plaque. A major component of the extracellular caseinolytic enzymes elaborated by strong producers seemed to be neutral zinc proteases. The extracellular proteases inactivated glucosyltransferase of Streptococcus mutans and inhibited the synthesis of adherent glucans from sucrose. The enzymes also degraded the Strep. mutans cell-surface receptor for dextran and glucan, the receptor for salivary agglutinins, located on Streptococcus sanguis cells, and the surface component of Actinomyces viscosus cells involved in co-agglutination with Strep. sanguis cells. The enzymes hydrolysed human whole saliva proteins, which seemed to result in loss of the ability to agglutinate Strep. sanguis cells.

Actinomyces↗
PubMed1983

Ca2+ release in the endoplasmic reticulum of guinea pig peritoneal macrophages.

Passive permeability of the endoplasmic reticulum of saponin-treated macrophages to Ca2+ was studied by the filtration method using 45Ca. The Ca2+ release from the endoplasmic reticulum of macrophages was enhanced by the presence of submicromolar concentrations of Ca2+ in the medium. The Ca2+ release was enhanced by caffeine, and suppressed by MgCl2. These phenomena are similar to the Ca2+-induced Ca2+ release reported for the sarcoplasmic reticulum of skeletal muscle. On the other hand, adenine suppressed the Ca2+ release from the endoplasmic reticulum, while it reportedly enhanced the Ca2+-induced Ca2+ release of the skeletal muscle. The threshold concentration of Ca2+ for the Ca2+-induced Ca2+ release was approximately 10(-8) M in the presence of 0.95 mM MgCl2 in macrophages. The spontaneous spreading of macrophages and spontaneous migration of macrophages were inhibited by adenine, and also by caffeine in spite of the enhancement of the Ca2+-induced Ca2+ release.

Animals↗
PubMed1983

Isolation and characterization of the outer membrane from Vibrio parahaemolyticus.

The outer membrane of Vibrio parahaemolyticus strain 3283-61 (serotype O2:K3) was isolated from blebs released upon spheroplast formation, in the presence of lysozyme and EDTA, by isopycnic sucrose density gradient centrifugation. SDS-PAGE of the outer membrane fraction prepared from cells grown in nutrient broth containing 3% (w/v) NaCl revealed five major proteins, designated a to e, with apparent approximate molecular weights: a, 44 000; b, 36 000; c, 33 500; d, 26 500; e, 22 000. An increase in NaCl concentration in the growth medium resulted in an increase of proteins b and c, whereas a decrease to 0.5% (w/v) induced two additional major proteins with respective molecular weights of about 35 000 and 32 000. Proteins a and b appeared to be loosely associated with the peptidoglycan layer since they were largely retained after extraction with 2% (w/v) SDS at 50 degrees C for 30 min. Proteins c and/or e may play a role in phage VP1-receptors since phage-resistant mutants derived from strain 3283-61 had significantly diminished amounts of both proteins. The major outer membrane proteins varied in number and molecular weight in strains of V. parahaemolyticus belonging to different K-serotypes.

Bacterial Outer Membrane Proteins↗
PubMed1983

Role of primers in glucan synthesis by glucosyltransferases from Streptococcus mutans strain OMZ176.

The effects of isomaltosaccharides of various molecular weights (isomaltose to dextran T2000) on glucan synthesis by a water-soluble glucan-synthesizing glucosyltransferase enzyme (GTase-S) and a water-insoluble glucan-synthesizing enzyme (GTase-I), both from Streptococcus mutans OMZ176, were examined. The activity of GTase-S was not affected by the addition of the isomaltosaccharides, but GTase-I was stimulated increasingly by isomaltosaccharides with degrees of polymerization more than 10. The GTase-I activity first increased and thereafter decreased slightly with increasing amounts of a soluble dextran. Maximal stimulation occurred at concentrations in the range 0.1 to 0.2 mg ml-1, when dextran T10 was used as a primer. The rate of glucan synthesis was highly enhanced by the combined action of GTase-S and GTase-I. The profile of the net activity of GTase-I in the presence of various amounts of GTase-S was similar to that of GTase-I in the presence of increasing amounts of an exogenous dextran. These results collectively suggest that soluble glucan produced by GTase-S from sucrose acts as an intrinsic primer for the glucan synthesis by GTase-I, indicating the contribution of autopriming in glucan synthesis by crude GTase of S. mutans.

Dextrans↗
PubMed1983

Isolation and partial properties of a porin-like protein from Vibrio parahaemolyticus cell envelope.

The cell envelope of Vibrio parahaemolyticus pilot strain K-11 contains a major protein with an apparent molecular weight of 35,000 which was not solubilized with 2% sodium dodecyl sulfate (SDS) at 50 C for 30 min and was resistant to trypsin. The protein was extracted from the SDS-insoluble envelope with SDS containing 0.4 M NaCl and purified by acetone precipitation and gel filtration. The purified protein was completely dissociated into a monomer with a molecular weight of 35,000 in SDS at 60 C. The amino acid composition of the protein was nearly the same as that of porins from Escherichia coli and Salmonella typhimurium. Thus the protein seems to be porin-like.

Amino Acids↗
PubMed1983

Biological activities of guinea pig mitogenic factor from immune lymphocytes stimulated with antigen.

Mitogenic factor was produced by sensitized guinea pig lymph node cells stimulated with a specific antigen. Both T lymphocytes and macrophages were required for the production of this factor. The culture supernatant of lymphocytes containing the mitogenic factor exhibited a strong helping effect on the proliferative response of T lymphocytes to phytohemagglutinin (PHA). Mitogenic factor and the factor with the helping activity coeluted in the molecular weight range of 25,000-35,000 daltons in gel filtration. Furthermore the fraction containing mitogenic factor was found to support the proliferation of lymphoblasts induced by PHA or antigen, suggesting that the mitogenic factor may be the guinea pig equivalent of T cell growth factor (TCGF) reported in the mouse, rat, and human. On the other hand, the T cell-activating monokine of the guinea pig, possessing the helping activity for the proliferative response of T lymphocytes to PHA, never exhibited TCGF-like activity.

Animals↗
PubMed1983

Purification and immunochemical characterization of Streptococcus sanguis serotype I carbohydrate antigen.

The serotype-specific antigen of Streptococcus sanguis ST3 (serotype I, biotype A) was extracted, chromatographically purified, and characterized by immunological and chemical methods. The antigen was extracted from purified cell walls with hot trichloroacetic acid, followed by ion-exchange chromatography on a DEAE-Sephadex A-25 column and gel filtration through a Sephadex G-100 column. A peak fraction was obtained that gave a single precipitin band when reacted with anti-type I serum. The type I antigen was a polysaccharide composed of glucose, rhamnose, and N-acetylglucosamine in a molar ratio of 1.4:2.5:1.0. Quantitative precipitin inhibition tests with various haptenic sugars indicated that an alpha-glucosidic linkage is the immunodeterminant of the type I antigen.

Chromatography, Gel↗
PubMed1983

Purification and immunochemical characterization of Streptococcus sanguis ATCC 10557 serotype II carbohydrate antigen.

Cell wall carbohydrate antigen of Streptococcus sanguis ATCC 10557 (serotype II/biotype B) was extracted from purified cell walls by treatment with 5% trichloroacetic acid at 4 degrees C for 8 h. The extract was purified by chromatography on DEAE-Sephadex A-25 and Sephadex G-100 columns. The purified carbohydrate antigen produced a single precipitin band against anti-type II serum, which fused with the band produced by the autoclaved extract or the phenol-water extract of the S. sanguis cells. The type II antigen was a polysaccharide composed of glucose, galactose, rhamnose, and N-acetylgalactosamine in a molar ratio of approximately 3:6:3:2. Quantitative precipitin inhibition tests with various haptenic sugars indicated that N-acetylgalactosamine was a major determinant of the type II antigen.

Amino Acids↗
PubMed1983

Characterization of a mutant of serotype g Streptococcus mutans strain 6715 lacking dextran-induced agglutination.

A spontaneous mutant of Streptococcus mutans 6715 (serotype g) defective in dextran-induced agglutination ability was isolated. The wild type strain and its mutant were termed as 6715-DP and 6715-DN, respectively. Both strains possessed serotype g antigen, and exerted similar sugar fermentation patterns. Strain 6715-DP was rapidly and strongly agglutinated upon addition of high molecular weight dextran, whereas the mutant strain 6715-DN was not. [14C]Dextran prepared from Leuconostoc mesenteroides dextransucrase and [14C]sucrose bound to fresh or lyophilized 6715-DP cells, but not to the mutant 6715-DN cells. However, both strains adhered to a glass surface in the presence of sucrose. Furthermore, heat-treated (100 degrees C, 10 min) cells of both strains bound cell-free glucosyltransferase, although dextran agglutination ability of strain 6715-DP was destroyed by this treatment, indicating that receptors for dextran and glucosyltransferase were different entities. Furthermore, serotype c, e, and f strains S. mutans did not agglutinate upon addition of dextran, nor did they bind [14C]dextran. However, all these strains and both 6715-DP and 6715-DN strains induced marked dental caries in SPF rats. It is concluded that dextran-induced agglutination ability is not a necessary condition for S. mutans to induce dental caries.

Agglutination↗
PubMed1983

[Clinical evaluation of josamycin for the treatment of Mycoplasma pneumonia in children].

Thirty-one strains of Mycoplasma pneumoniae were tested for drug sensitivity to both josamycin (JM) and erythromycin (EM), to evaluate the efficacy of JM for mycoplasmal pneumonia in children. In addition to the sensitivity tests of 31 M. pneumoniae strains against JM and EM, 50 patients, between the ages of 3 years 1 month and 13 years 3 months, suspected of suffering from mycoplasmal pneumonia were treated with 50 or 200 mg JM tablets at an average daily dose of 43.1 mg/kg t.i.d. or b.i.d. for an average period of 14 days; an additional 31 patients between the ages of 2 years 9 months and 11 years, suspected of suffering from this disease were treated with tablet or dry syrup of EM, with the exception of EM estolate, t.i.d. or b.i.d. at an average daily dose of 72.5 mg/kg for an average period of 15 days. Patients were selected in 37 and 22 mycoplasmal pneumonic patients respectively for JM and EM. Clinical and bacteriological effects, efficacy and side effects of the drugs on this disease were studied and the following results were obtained. Drug sensitivity test Of all 31 strains tested for JM sensitivity the populations which exhibited 0.125 mcg/ml were most abundant (18/31, 58.1%) and MIC pattern of all strains were distributed from 0.0313 to 0.125 mcg/ml. In the EM group, 61.3% (19/31) of the populations were sensitive at 0.015 mcg/ml, exhibiting the dominant distribution pattern and MIC range of all organism varied from 0.0078 to 0.0313 mcg/ml. Resistant strains were found to neither JM nor EM. EM was approximately 2 to 10 times more active than JM in MIC evaluation. Clinical effects of JM by daily doses Clinical effects relative to the daily dose were evaluated in 3, 7, 10 days after administration of drugs. The response was favorable, according to assessments of the attending doctors, in 96.7, 100% and 95.8% of the patient group given JM in a daily dose of 40-49 mg/kg, the group to which the largest number of patients belonged. Similar favorable results were obtained by the assessments of Evaluation Committee, showing 86.7, 96.7% and 100% of favorable response. Upon comparison, in the same interval, of these results with those of the groups given EM in a daily dose of 50 mg/kg, the group in which the largest number of patients were seen, there was no significant difference in the assessments either of the attending doctors or of the Evaluation Committee.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1983

[Clinical effects of an ampicillin suppository (KS-R1) in urinary tract infection of children].

Clinical effects of ampicillin suppository (KS-R1) were examined in 24 children (11 male and 13 female) aged from 5 months to 7 years 5 months with urinary tract infection. KS-R1 was rectally given to the patients at doses of average 45.6 mg/kg/day divided into 3 to 4 times for average 8 days. Clinical effectiveness was 95.8%. Bacteriologically, the eradication of isolated organisms was observed in 10 (71.4%) out of 14 cases, the decrease in 3 (21.4%) and the persistence in 1 (7.1%). The discharge of suppository within 5 minutes after insertion was observed in 8.7% of patients without diarrhea and in 6.9% of patients with diarrhea. The evacuation rate of the bowels within 10 minutes after insertion was observed in 5.9% of patients without diarrhea and in 41.9% of patients with diarrhea. It was suggested that the administration of KS-R1 to childish patients with diarrhea should be careful. As to the side effects, diarrhea was observed in 2 cases (7.1%) and the elevation of GPT and GOT in 1 case (3.6%).

Age Factors↗