Biomedical subjects

R Ikegami

Publications and source records attributed to R Ikegami.

35 records · Page 2Linked to original sources

PubMed1986

[Midecamycin acetate-susceptibility of clinical isolates from dental and oral surgical infections].

To investigate the clinical and bacteriological usefulness of orally administered midecamycin acetate (MOM), the susceptibility of clinical isolates to MOM, Mb-12 (the main metabolite of MOM), josamycin (JM), ampicillin (ABPC) and cephalexin (CEX) was determined. The results are summarized as follows. Antibacterial activities of MOM against aerobic Gram-positive cocci, B. catarrhalis, and anaerobic bacteria were inferior to those of JM by 2-fold, but superior to those of CEX. Activities of MOM against S. aureus, Bacteroides spp., Fusobacterium spp., Veillonella spp. were superior to those of ABPC and CEX. Since serum and tissue concentrations of Mb-12 after 200 mg administration in humans have been reported to be 1-2 micrograms/ml, it can be presumed that the causative bacteria would be eradicated by a usual dosage of MOM used in the present study. From these considerations, it is speculated that MOM may be successfully used in the treatment of dental and oral surgical infections.

Ampicillin↗

PubMed1985

[Study on the drug sensitivity of multiple drug-resistant Staphylococcus aureus].

Of clinically isolated Staphylococcus aureus showing resistance to multiple drugs among penicillins (PCs), cephem antibiotics (CEPs), aminoglycosides (AGs), minocycline (MINO) and fosfomycin (FOM), 64 strains were selected for the determination of MIC. Twenty-one drugs were used for the determination of MIC, with ampicillin (ABPC), cloxacillin (MCIPC), cephalothin (CET), cefazolin (CEZ), cefotiam (CTM), cefuroxime (CXM), cefamandole (CMD), cefotaxime (CTX), ceftizoxime (CZX), cefmenoxime (CMX), cefmetazole (CMZ), cefoxitin (CFX), latamoxef (LMOX), cefotetan (CTT), cefoperazone (CPZ), gentamicin (GM), dibekacin (DKB), tobramycin (TOB), amikacin (AMK), MINO, and FOM. MIC80 of each drug at 10(6) CFU/ml were: ABPC, MCIPC, CEZ, CTM, CXM, CTX, CZX, CMX, CFX, LMOX, CTT, CPZ, GM, DKB and TOB greater than 100 micrograms/ml; CET 50 micrograms/ml; CMD and AMK 25 micrograms/ml; CMZ 12.5 micrograms/ml; FOM 6.25 micrograms/ml; and MINO 0.78 micrograms/ml. The ratio of highly resistant strains with MIC greater than 100 micrograms/ml at 10(6) CFU/ml varied according to drug, and a difference tended to be seen in the degree of influence by resistant factors reflected upon MIC, e.g. drugs for which a high resistance of more than 50% was confirmed were ABPC, CXM, CZX, LMOX and TOB, and 20 approximately 30% MCIPC, CTM, CTX, CMX and CFX. MIC on MCIPC which has a correlation of structural activity with methicillin correlated with cephems (CEPs) resistance to a high degree, but many of the so-called new CEPs showed resistance even to the strains with a low MIC on MCIPC. It was assumed that CEPs resistant strains have multiple drug resistant factors based on the fact that such strains showed multiple drug resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminoglycosides↗

PubMed1985

[In vitro susceptibilities of causative organisms isolated from patients with primary respiratory tract infections to BRL 25000 (clavulanic acid/amoxicillin)].

The in vitro susceptibilities of various causative organisms recently isolated from patients with primary respiratory tract infections to BRL 25000 (a formulation of amoxicillin, 2 parts, and potassium clavulanate, 1 part), amoxicillin (AMPC), cefaclor (CCL), cephalexin (CEX), cefadroxil (CDX) and cefroxadine (CXD) were determined. beta-Lactamase producing strains were detected by nitrocefin chromogenic method and PCG acidometric method. The frequency of isolation of beta-lactamase production in strains of S. aureus, H. influenzae, B. catarrhalis and K. pneumoniae was 92%, 18%, 36% and 98%, respectively. Against S. aureus strains with MIC values to AMPC of less than or equal to 100 micrograms/ml and CEX of less than or equal to 25 micrograms/ml BRL 25000 showed MIC values in the range 0.39-6.25 micrograms/ml with inocula of 10(6) CFU/ml, while BRL 25000 required 12.5-100 micrograms/ml of concentrations for inhibition of the strains with MIC values to AMPC of greater than 100 micrograms/ml and CEX of greater than or equal to 25 micrograms/ml. Against S. pyogenes and S. pneumoniae BRL 25000 showed MIC values in the range less than 0.024-0.10 micrograms/ml with inocula of 10(6) CFU/ml, which is much more active than CCL, CEX, CDX and CXD and slight less active than AMPC. Against H. influenzae and B. catarrhalis BRL 25000 showed MIC values in the range 0.20-6.25 micrograms/ml with inocula of 10(6) CFU/ml, which showed most potent activity among the agents tested. The activity of BRL 25000 against K. pneumoniae was approximately equal to that of CCL and superior to that of AMPC, CEX, CDX and CXD.

Amoxicillin↗

PubMed1985

[Distribution and changes in the susceptibility of bacteria isolated from clinical samples. II].

In vitro activity of antimicrobial agents such as ABPC, SBPC, MPC, CEZ, CTM, CMZ, CTX, CMX, CZX, LMOX, CPZ, CFS and GM against major clinical isolates, S. aureus, S. pyogenes, E. coli, K. pneumoniae, P. mirabilis, C. freundii, Enterobacter spp., S. marcescens, P. vulgaris and P. aeruginosa, was examined. In this paper, we will report the susceptibility of S. aureus, S. pyogenes, E. coli, K. pneumoniae and P. mirabilis during a three-year period, 1981 to approximately 1983. CEZ- and GM-resistant S. aureus has markedly increased and occupied 24% and 18%, respectively, in 1983. CMZ and CFS have showed potent activity against CEZ-resistant S. aureus. It seems that the abuse of third generation-cephems and new oral cephalosporins is closely related with the increase of cephems-resistant S. aureus. The penicillin- and cephem-resistant strains of S. pyogenes could not be found in our study. Quite a few strains of E. coli, K. pneumoniae and P. mirabilis are resistant to penicillins, and also there is no appreciable change in susceptibility. Some strains of E. coli, K. pneumoniae and P. mirabilis showed low susceptibility to CPZ, but all strains showed high susceptibility and no change in susceptibility to third generations, and these strains showed no tendency to decrease in susceptibility to GM.

Anti-Bacterial Agents↗

PubMed1985

[Study of clinical bacteriological efficacy in a cefmenoxime ototopical solution].

One percent cefmenoxime (CMX) ototopical solution was administered to 302 patients with purulent otitis media and acute diffuse external otitis in open study fashion, and to 216 patients with purulent otitis media in double blind condition. From among the total of 518 cases various bacteria were detected, except 22 of negative detection after incubation and 3 of impossible determination. The main bacteria detected from the above 493 cases were S. aureus (242 strains = 49.1%), P. aeruginosa (105 strains = 21.3%), S. epidermidis (67 strains = 13.6%), Proteus spp. (indole positive) (31 strains = 6.3%) and P. mirabilis (24 strains = 4.9%) as well as anaerobic bacteria (26 strains = 5.3%). MIC of CMX against those bacteria detected was evaluated at 10(8) CFU/ml and 10(6) CFU/ml, respectively, up to the concentration of 800 micrograms/ml, with MIC of cefazolin (CEZ), chloramphenicol (CP) and fradiomycin (FRM) as the references. With respect to the antibacterial action of CMX against S. aureus, MIC50 of CMX was inferior to that of CEZ by 4-fold, but its MIC80 and MIC90 are almost equivalent to those of CEZ. These results were obtained because there existed relatively few CMX highly resistant strains, while more than 20% strains are said to resist cephem antibiotics. As far as MIC of CMX against P. aeruginosa was concerned, the MIC reached its peak with 100 micrograms/ml at the concentration of 10(8) CFU/ml and with 25 micrograms/ml at 10(6) CFU/ml, respectively, which indicated the real antibacterial value of CMX against P. aeruginosa. However, the strains which showed higher MIC of greater than 800 micrograms/ml were rather few, that is, only 8 out of 105 (7.6%). Antibacterial action of CMX against Streptococcus (except Enterococcus), GNR from intestinal bacteria and anaerobic bacteria was favorable, and the stable and strong antibacterial action was shown against C. freundii, Enterobacter spp., S. marcescens and Proteus spp. (indole positive) which produce chromosome mediated beta-lactamase. On the other hand, the antibacterial action of CMX against GNF-GNR except P. aeruginosa was unfavorable for P. cepacia, P. putida and A. xylosoxidans, but relatively favorable for A. calcoaceticus. As a result of MIC evaluation of reference drugs, S. aureus was resistant to CEZ, and Proteus spp. (indole-positive) was resistant to CP, while FRM was highly resisted by almost all strains of bacteria. However, the resistance rate of S. aureus to CP was relatively low, that is, as low as 16.1%.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Topical↗

PubMed1985

[Distribution and changes in the susceptibility of bacteria isolated from clinical samples. III].

This report presents data concerning in vitro activity of antimicrobial agents against Citrobacter freundii, Enterobacter spp., Serratia marcescens and Proteus vulgaris isolated from patients with complicated urinary tract infections and against Pseudomonas aeruginosa isolated from surgical wounds with postoperative infection and exudate from superficial abscesses. There was a marked increase of resistant strains of C. freundii, Enterobacter spp. and S. marcescens to penicillins, CEPs or GM. The isolates of these species obtained in 1983 showed MIC values of 100 micrograms/ml or more for the so-called new CEPs (CTX, CMX, CZX, LMOX and CPZ). The P. vulgaris isolates exhibited an increasing incidence of strains resistant to penicillins, and data on P. vulgaris isolates in 1983 indicated increase of strains resistant to CEPs. GM-resistant organisms were also noted to be increasing among the isolate of this species. The analysis did not reveal any appreciable change with calendar years among P. aeruginosa in respect of frequency of strains resistant to SBPC or CEPs (except CPZ). The data obtained in 1983, however, showed an indication of increasing incidence of organisms resistant to CPZ and GM. The increasing tendency of emergence of organisms resistant to new CEPs designed to expand activity against C. freundii, Enterobacter spp., S. marcescens and P. vulgaris, observed among the isolates of these species is considered probably to be the consequence of bacterial selective acquisition of R plasmid that carry drug resistant genes against CEPs. These are exactly reflected in the present data obtained in studies initiated in 1981 when the new CEPs became commonly prescribed in the daily clinics. It is concluded, accordingly, that organisms of these species resistant to CEPs have been increasing throughout the country.

Anti-Bacterial Agents↗

PubMed1984

[MICs and MBCs of cefotaxime, desacetylcefotaxime and ceftriaxone against four principal bacteria causing meningitis].

The MICs and MBCs of cefotaxime (CTX), desacetylcefotaxime (Des-CTX) and ceftriaxone (CTRX) were determined in relation to 4 of the principal bacterial species which cause meningitis, i.e., S. pneumoniae, S. agalactiae, H. influenzae and E. coli. These tests were performed using final inocula of 10(8) cells/ml and 10(6) cells/ml. Comparison was made with the MIC and MBC values of benzylpenicillin (PCG) and ampicillin (ABPC). 1. Against 25 strains of S. pneumoniae, the MIC 90 values with inocula levels of 10(8) and 10(6) cells/ml were as follows: CTX, 0.05 and 0.024 micrograms/ml; Des-CTX, 0.39 and 0.20 micrograms/ml; CTRX, 0.10 and 0.05 micrograms/ml, respectively; and PCG, less than 0.012 micrograms/ml at both size. Similarly, the MBC 90 values were: CTX, 0.01 and 0.05 micrograms/ml; Des-CTX, 0.78 and 0.39 micrograms/ml; CTRX, 0.20 and 0.10 micrograms/ml; and PCG, 0.024 and 0.012 micrograms/ml, respectively. It is thus apparent that PCG showed the lowest values for both the MIC and MBC, followed by CTX, CTRX and then Des-CTX. Against 25 strains of S. agalactiae, the MIC 90 values with inocula of 10(8) and 10(6) cells/ml were as follows: CTX, 0.05 and 0.05 micrograms/ml; Des-CTX, 0.39 and 0.20 micrograms/ml; CTRX, 0.10 and 0.05 micrograms/ml; and PCG, 0.39 and 0.20 micrograms/ml, respectively. Similarly, the MBC 90 values of Des-CTX were 0.78 and 0.39 micrograms/ml, while the other 3 antibiotics showed the same values with both the 10(8) and 10(6) cells/ml inocula: 0.10 micrograms/ml for CTX, 0.20 micrograms/ml for CTRX and 0.39 micrograms/ml for PCG. Accordingly, CTX showed the lowest values, followed by CTRX and then PCG being about the same as Des-CTX. Against 25 strains of H. influenzae, the MIC 90 values with inocula levels of 10(8) and 10(6) cells/ml were as follows: CTX, 0.10 and 0.05 micrograms/ml; Des-CTX, 0.39 and 0.39 micrograms/ml; CTRX, 0.10 and 0.05 micrograms/ml; and ABPC, 50 and 6.25 micrograms/ml, respectively. Similarly, the MBC 90 values were: CTX, 0.20 and 0.10 micrograms/ml; Des-CTX, 1.56 and 1.56 micrograms/ml; CTRX, 0.39 and 0.20 micrograms/ml; and ABPC, greater than 100 and 50 micrograms/ml, respectively. Accordingly, in terms of the MIC 90, CTX and CTRX showed the same values, but in terms of the MBC 90 CTX was superior. (ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1984

Establishment of a tumor-specific immunotherapy model utilizing TNP-reactive helper T cell activity and its application to the autochthonous tumor system.

Preinduction of potent hapten-reactive helper T cell activity and subsequent immunization with hapten-coupled syngeneic tumor cells result in enhanced induction of tumor-specific immunity through T-T cell collaboration between anti-hapten helper T cells and tumor-specific effector T cells. On the basis of this augmenting mechanism, a tumor-specific immunotherapy protocol was established in which a growing tumor regresses by utilizing a potent trinitrophenyl (TNP)-helper T cell activity. C3H/He mice were allowed to generate the amplified (more potent) TNP-helper T cell activity by skin painting with trinitrochlorobenzene (TNCB) after pretreatment with cyclophosphamide. Five weeks later, the mice were inoculated intradermally with syngeneic transplantable X5563 tumor cells. When TNCB was injected into X5563 tumor mass, an appreciable number of growing tumors, in the only group of C3H/He mice in which the amplified TNP-helper T cell activity had been generated were observed to regress (regressor mice). These regressor mice were shown to have acquired tumor-specific T cell-mediated immunity. Such immunity was more potent than that acquired in mice whose tumor was simply removed by surgical resection. These results indicate that in situ TNP haptenation of the tumor cells in TNP-primed mice can induce the enhanced tumor-specific immunity leading to the regression of a growing tumor. Most importantly, the present study further investigates the applicability of this TNP immunotherapy protocol to an autochthonous tumor system. The results demonstrate that an appreciable percent of growing methylcholanthrene-induced autochthonous tumors regressed by the above TNP immunotherapy protocol. Thus, the present model provides an effective maneuver for tumor-specific immunotherapy in syngeneic transplantable as well as autochthonous tumor systems.

Animals↗

PubMed1982

The restoration of suppressed T cell activities induced by 7,12-dimethylbenz[a]anthracene with an anti-tumor immunomodulator, BCG-cell wall skeleton.

The restoring effect of Bacille de Calmette et Guérin (BCG)-cell wall skeleton (CWS) on the suppressed T cell reactivities in mice treated with 7,12-dimethylbenz[a]anthracene (DMBA) was studied using a system involving the induction of hapten-reactive cytotoxic T cells and mixed lymphocyte reaction in vitro. When the mice were treated with DMBA, the reactivity of lymphoid cells to generate cytotoxic T cells and proliferative T cell responses against allogeneic spleen cells was markedly suppressed. When BCG-CWS was administered to mice by intravenous injection before and after the treatment with DMBA, these depressed T cell functions reverted completely to the normal level. However, the restoration of the immune functions by BCG-CWS varied depending on the strain of mice. Namely, the reactivity of C57BL/6 mice was restored by BCG-CWS, whereas that of C3H/He mice was not. This strain difference correlates very well with the strain difference in effectiveness of the prevention of the DMBA-induced tumorigenesis by BCG-CWS. The possible relation between the restoration of T cell reactivities by BCG-CWS and prevention of tumorigenesis by BCG-CWS is discussed in the context of the role of host immune surveillance in the regulation of tumor development.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1979

Prophylactic effect of BCG cell-wall skeleton on the tumor induction by 7,12-dimethylbenz[a]anthracene in mice: strain difference.

Prophylactic effect of repeated intravenous administrations of oil-attached BCG cell-wall skeleton (BCG-CWS) on the induction of tumor by 7,12-dimethylbenz[a]anthracene (DMBA) was investigated in various strains of mice. The subcutaneous injection of DMBA emulsified in oil induced squamous cell carcinoma in almost all of the strains of mice. Treatment of C57BL/6, BALB/c, and ddO strains with BCG-CWS with appropriate route and timing resulted in the retardation of DMBA-induced tumor development manifested by a prolonged latent period of tumor outgrowth. In contrast, the same BCG-CWS treatment of C3H/He and BTK mice was incapable in preventing such DMBA-induced carcinogenesis. Thus, the treatment with BCG-CWS was effective for preventing the DMBA-induced carcinogenesis in certain strains of mice, but the effectiveness varied depending on the strain. The implication of such a strain variationof the BCG-CWS effect on the prophylaxis of chemical carcinogenesis was discussed in the context of differences in the magnitude of immunopotentiation of the host by BCG-CWS.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1969