Biomedical subjects

M Koguchi

Publications and source records attributed to M Koguchi.

At least 19 recordsLinked to original sources

PubMed2001

Three-dimensional STEM for observing nanostructures.

A new scanning transmission electron microscope has been developed for three-dimensional (3D) observations of nanostructures. Using double spherical fulcra, accurate eucentric rotation was achieved. Cylindrical specimens for 3D-observation were prepared by a microsampling technique using a focused ion beam. Copper via-holes of a semiconductor memory device and ZnO particles were observed by the 3D-STEM from different directions, and 3D-data of the ZnO particles were successfully reconstructed in a topography mode.

Journal Article↗

PubMed1996

[Antimicrobial activities of meropenem against clinically isolated strains].

In order to evaluate antimicrobial activity of meropenem (MEPM), minimum inhibitory concentrations (MICs) of MEPM and control drugs were determined against clinical isolates in 1993. The results were as follows; 1. Antimicrobial activities of MEPM against Gram-positive bacteria were stronger than those of cephems (CEPs), were approximately equal to those of panipenem (PAPM), and were weaker than those of imipenem (IPM). 2. Carbapenems showed strong antimicrobial activities against Enterobacteriaccae, glucose non-fermentative Gram-negative rods and Bacteroides fragilis group that were multiple drug resistant including the third generation CEPs. Antimicrobial activities of MEPM against these organisms were stronger than those of IPM and PAPM. 3. MIC-ranges of MEPM against Enterobacteriaceae and Haemophilus influenzae were lower than those of IPM and PAPM. We observed that MEPM had better permeability into the cells of H. influenzae, higher affinities to 3 to 5 different penicillin-binding protein and high stability against beta-lactamase than those of IPM and PAPM.

Bacteria↗

PubMed1996

[Antibacterial activities of combination uses of isepamicin and beta-lactams in vitro against clinically isolated strains. Part 1. Activities against Staphylococcus aureus].

In order to evaluate antibacterial activities of combination uses of isepamicin (ISP) and beta-lactams in vitro, minimum inhibitory concentrations (MICs) these drugs were examined singly and in combination against clinically isolated Staphylococcus aureus. The results are summarized as follows; 1. MICs of ISP + cefazolin (CEZ), ISP + cefotiam (CTM) and ISP + flomoxef (FMOX) were low and the activities against methicillin (DMPPC)-susceptible S. aureus (MSSA) were dependent on the concentration of ISP. Combined effects were observed when the concentrations of ISP were at sub-MIC levels (1/2 approximately 1/4 concentrations). 2. MICs of ISP + CEX, ISP + CTM, ISP + FMOX, ISP + imipenem and ISP + panipenem were low and the activities against DMPPC-resistant S. aureus (MRSA) were dependent on the concentration of ISP, and were similar to those against MSSA. Combined effects were observed when the concentrations of ISP were at sub-MIC levels of ISP. Lower MIC50 or MIC90 was observed at ISP concentrations of 4 approximately 16 micrograms/ml. 3. The blood Cmax of ISP exceeded 20 micrograms/ml at one-time administration of ISP 400 mg, and these results suggested that antibacterial activities of combination uses of ISP and beta-lactams was clinically effective against MRSA infections.

Anti-Bacterial Agents↗

PubMed1996

[Antibacterial activities of combination uses of isepamicin and beta-lactams in vitro against clinically isolated strains. Part 3. The results against Pseudomonas aeruginosa].

We investigated antibacterial activities of combination uses of isepamicin (ISP) and beta-lactams in vitro against Pseudomonas aeruginosa, and the following conclusions were obtained. 1. ISP + piperacillin, ISP + ceftazidime, ISP + aztreonam, ISP + imipenem and ISP + panipenem against P. aeruginosa showed strong combined effects. 2. The minimum inhibitory concentrations (MICs) of these combinations were low and dependent on concentrations of ISP. And strong antibacterial activities were observed at ISP concentrations of sub-MIC levels. These results were similar to the results of previous reports, parts 1 and 2. 3. Concentrations of ISP sufficient to lower MIC90 values when by combined with beta-lactam agents were 4 approximately 8 micrograms/ml. These effects made it possible to lower the ISP dose to 400 mg at a single dose and the enhancement of activities by combinations resulted in strong antibacterial activities against multiple drug resistant stains at sub-MIC levels of ISP. Strong antibacterial activities were also obtained against beta-lactams-resistant strains of ISP-susceptible strains when ISP was combined with beta-lactam agents. 4. All results reported in parts 1 approximately 3 indicated that no antagonisms were produced by combining ISP + penicillins, ISP + cephems, ISP + monobactams and ISP + carbapenems against Staphylococcus aureus, Enterobacteriaceae and P. aeruginosa. These combinations showed strong antibacterial activities that were enhanced synergistically with wider spectra.

Anti-Bacterial Agents↗

PubMed1996

[Antimicrobial activities of meropenem against clinically isolated strains. The result against strains isolated from blood and cerebrospinal fluid].

In order to evaluate the antimicrobial activity of meropenem (MEPM), minimum inhibitory concentrations (MICs) of MEPM and control drugs were determined against clinical isolates from blood and cerebrospinal fluid that were obtained from January, 1993 to December, 1994. The results are summarized as follows; 1. The MIC-range, 50% MIC (MIC50) and 90% MIC (MIC90) of MEPM were equal to those of imipenem (IPM) and panipenem (PAPM) against Streptococcus pneumoniae including benzylpenicillin (PCG)-insensitive or -resistant S. pneumoniae, Streptococcus agalactiae and Listeria monocytogenes which are Gram-positive strains, and were stronger than those of ampicillin (ABPC) and cefotaxime (CTX). 2. The MIC-range, MIC50 and MIC90 of these 3 drugs of carbapenems (MEPM, IPM and PAPM) were different against Escherichia coli and Haemophilus influenzae which are Gram-negative strains. The MIC90 of MEPM was < or = 0.025 microgram/ml and those of IPM and PAPM were 0.2 microgram/ml against E. coli. The MIC90 of MEPM was 0.1 microgram/ml, that of IPM was 25 micrograms/ml and that of PAPM was 6.25 micrograms/ml against H. influenzae. Thus, the antimicrobial activity of MEPM was stronger than those of IPM and PAPM. The MIC90's of IPM and PAPM against H. influenzae were high with the MIC of IPM at 12.5 approximately 25 micrograms/ml and the MIC of PAPM at 3.13 approximately 12.5 micrograms/ml against 3 IPM-resistant strains among 17 isolates. 3. The MIC90 of ABPC was 0.39 microgram/ml and that of CTX was 0.1 microgram/ml against 20 strains of S. pneumoniae including 6 strains of PCG-insensitive or resistant S. pneumoniae. The MIC90 of ABPC and CTX were higher than those of 3 carbapenem drugs. There were E. coli of 8 strains with ABPC-high resistance (the MIC of ABPC was > 100 micrograms/ml) and 2 strains for which MIC of CTX were 0.39 microgram/ml and 3.13 micrograms/ml. It was found that 29.4% of H. influenzae were beta-lactamase producing strains. 4. It appeared that antimicrobial activities of carbapenems, particularly MEPM were strong against clinical isolates from blood and cerebrospinal fluid. MEPM will be first choice drug by empiric therapy in infections including sepsis and purulent meningitis.

Ampicillin↗

PubMed1996

[Antimicrobial activities of cefozopran against Streptococcus pneumoniae from children].

In order to evaluate antimicrobial activity of cefozopran (CZOP), minimum inhibitory concentrations (MICs) of CZOP and control drugs were determined against Streptococcus pneumoniae from children that were isolated from October of 1995 to January of 1996. Determinations were made for the detection frequency of penicillin-insensitive or resistant strains in biovar utilizing hydrolysis products, and for the correlation of antibacterial susceptibility and macrolides (MLs)-resistant patterns. The results are summarized as follows; 1. MIC90 of CZOP was < or = 0.025 micrograms/ml against benzylpenicillin (PCG)-susceptible S. pneumoniae (PSSP, 50 strains). MIC distribution of CZOP against these strains was approximately equal to that of PCG, and showed stronger activities of CZOP than those of ceftazidime (CAZ), flomoxef (FMOX) and erythromycin (EM). 2. MIC90 of CZOP was 0.39 micrograms/ml against 50 strains of PCG-insensitive S. pneumoniae (PISP) and PCG-resistant S. pneumoniae (PRSP). Antimicrobial activities of CZOP against these strains were stronger than those of CAZ, FMOX, PCG and EM. 3. These isolated strains of PISP and PRSP did not show type III biovar, but showed types I and II. The detection frequency of MLs-constitutive resistant strains were high among type III PSSP and those of MLs-inductive resistant strains were high among types I and II PISP and PRSP. These data suggested that CZOP had strong antimicrobial activities against multiple drug resistant S. pneumoniae including penicillin-resistant strains. CZOP will be effective against S. pneumoniae which often are causative organisms in infections of children.

Anti-Bacterial Agents↗

PubMed1996

[Antibacterial activities of combination uses of cefpirome with various antibiotics in vitro against clinically isolated glucose non-fermentative gram-negative rods: part 1. the results against Pseudomonas aeruginosa].

In order to evaluate antibacterial activities of combination uses of cefpirome (CPR) and various antibiotics in vitro, minimum inhibitory concentrations (MICs) of CPR alone and combinations of CPR+other drugs against freshly isolated clinical strains of Pseudomonas aeruginosa. The results are summarized as follows; 1. Combined effects of CPR+beta-lactams, piperacillin (PIPC), aztreonam (AZT), imipenem (IPM) showed wider antibacterial spectra and stronger antibacterial activities than CPR alone with drugs concentrations of CPR and other drugs at sub-MIC levels. At concentrations of sub-MIC levels, antibacterial effects of CPR+PIPC and CPR+AZT combination were strong but CPR+IPM was weaker than those of the former two combinations. It appeared that stronger effects were demonstrated by some combinations against strains that were susceptible to both drugs of combination, but little additive effects were shown against strains that were resistant to both drugs. Antibacterial effect of CPR+fosfomycin combination was the same as those of CPR+PIPC and CPR+AZT combinations. 2. Combined effects of CPR+aminoglycosides (AGs), gentamicin, tobramycin, amikacin showed wider antibacterial spectra and stronger antibacterial activities at sub-MIC levels of CPR or ATs. The effect against CPR-resistant strains was same. But the combined effect was weak against AGs-resistant strains. 3. Effectiveness of combinations of CPR+beta-lactams and CPR+AGs depended on drug susceptibilities of strains tested. We cannot estimate effects of those combinations without investigating drug susceptibility of bacteria being tested. 4. In none of the combinations tested, antagonism was observed.

Amikacin↗

PubMed1996

[Antimicrobial activities of ceftriaxone against fresh, clinically isolated strains].

In order to evaluate antimicrobial activity of ceftriaxone (CTRX), minimum inhibitory concentrations (MICs) of CTRX and control drugs were determined against clinically isolated strains including those from purulent meningitis and liver and biliary tract infections in 1995. The results are summarized as follows; 1. MIC90 of CTRX was 0.05 micrograms/ml against benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae or PCG-resistant S. pneumoniae and it was < or = 0.025 micrograms/ml against beta-lactamase producing strains of Haemophilus influenzae. Antimicrobial activities of CTRX against these strains were stronger than control drugs. 2. MIC distribution of CTRX was in a lower concentration range than those of ceftazidime and flomoxef against extend broad-spectrum beta-lactamase (EBLA)-producing Escherichia coli and Klebsiella pneumoniae subsp. pneumoniae. 3. These results suggested that CTRX will be effective against community-acquired pneumonia, purulent meningitis and liver & biliary tract infections.

Biliary Tract Diseases↗

PubMed1996

[Antibacterial activities of combination uses of isepamicin and beta-lactams in vitro against clinically isolated strains. Part 2. The results against enterobacteriaceae].

We investigated antibacterial activities of combination uses of isepamicin (ISP) and beta-lactams in vitro against Klebsiella pneumoniae and Enterobacter cloacae, and the following conclusions were obtained. 1. ISP+cefazolin, ISP+cefotiam and ISP+flomoxef against K. pneumoniae and ISP+piperacillin, ISP+ceftazidime, ISP+aztreonam, ISP+imipenem and ISP+panipenem against E. cloacae showed strong combined effects. 2. The minimum inhibitory concentrations (MICs) of these combinations were low due to the dependence of ISP concentrations. Strong antibacterial activities were observed at sub-MIC levels of ISP. These combined effects were stronger than those against Staphylococcus aureus described in the first report at sub-MIC levels of ISP. 1/4 MIC approximately 1/8 MIC of ISP showed enhanced activities of beta-lactams. Similarly strong combined effects were observed against both beta-lactam-sensitive and -resistant strains.

Anti-Bacterial Agents↗

PubMed1996

[Antimicrobial activities of clarithromycin against clinical isolates].

To examine the antimicrobial activity of clarithromycin (CAM) against strains clinically isolated from outpatients in 1994, minimum inhibitory concentrations (MICs) were determined for CAM and the control drugs. The results were as follows; 1. MIC50 and MIC90 of CAM were similar to those investigated in 1980's against many bacterial species. 2. CAM showed strong antimicrobial activities against beta-lactamase producing Moraxella subgenus Branhamella catarrhalis, Bordetella pertussis, Campylobacter jejuni subsp. jejuni and Peptostreptococcus spp. 3. It appears that resistance to MLs including CAM is increasing among Streptococcus pneumoniae.

Anti-Bacterial Agents↗

PubMed1995

[Antimicrobial activities of norfloxacin against clinical isolates from ocular infections].

In order to evaluate antimicrobial activity of norfloxacin (NFLX), minimum inhibitory concentration (MICs) of NFLX and control drugs were determined against clinical isolates from ocular infections that were obtained in our laboratory from July, 1993 to December, 1994. The results are summarized as follows; 1. Compared to MIC distributions of NFLX against clinical isolates from ocular infections studied in 1986 and 1987, the MIC80 of NFLX against Corynebacterium spp., Enterobacter spp., Serratia spp., Burkholderia cepacia, Flavobacterium spp., Alcaligenes spp. increased 8 times. Almost all of NFLX-resistant strains among them were ofloxacin (OFLX)-resistant, new quinolones resistant strains, and a part of them were aminoglycosides, beta-lactams-resistant as well, thus all of these strains were multiple drug resistant. 2. MIC of NFLX against Pseudomonas aeruginosa were lower than that of OFLX. 3. NFLX showed strong antimicrobial activities against so-called "particular bacteria" including Staphylococcus aureus subsp. aureus, Moraxella spp., Haemophilus spp., and P. aeruginosa from ocular infections. And MIC80 of NFLX against these bacteria was 0.05-1.56 microgram/ml. We observed that NFLX eye drops was administered so that concentrations above the MIC against these clinical isolates were maintained.

Anti-Infective Agents↗

PubMed1995

[Study of clinically isolated new quinolones-resistant Haemophilus influenzae. Part 1].

A study was done to determine susceptibilities of Haemophilus influenzae that were obtained in our laboratory in 1994 to new quinolones (NQ) and other drugs. The results were as follows; 1. Among the 300 isolates, the detection frequency of NQ-resistant strains was 8.7% (26 strains), including isolates from chronic lower respiratory tract infections (22 strains) and those from middle meatus of nose (2 strains), etc. NQ-resistant strains were not isolated from children. 2. The cross resistance was studied for different NQs against NQ-resistant strains. Clavulanic acid/amoxicillin, cefteram, cefpodoxime, cefditoren, cefodizime (CDZM) and cefpirome showed strong antimicrobial activities against NQ-resistant strains. MIC90 of CEPs against all isolated strains including NQ-resistant strains and beta-lactamase producers was low. And the MIC90 of CDZM was < or = 0.025 microgram/ml, which was the lowest among all the antibiotics tested. 3. We found 47 strains (15.7%) of beta-lactamase producers among the 300 isolates, the frequency of beta-lactamase producing strains was high among strains obtained from children.

Anti-Infective Agents↗

PubMed1995

[Frequency of clinical isolation of glucose non-fermentative gram-negative rods and their susceptibilities to antibacterial agents].

A comparison was made for frequencies of isolation o glucose non-fermentative Gram-negative rods ((G)NF-GNR) from clinical specimens during a period from July, 1986 to June, 1987 (the first period) and that from January, 1994 to December, 1994 (the second period). Also, minimum inhibitory concentrations of principal drugs were determined against these isolates. The obtained results are summarized as follows: 1. Thirty four (34) species of (G)NF-GNR were found from 35,200 clinical specimens in the two periods. Numbers of strains of (G)NF-GNR obtained were 4,575 during the first period and 4,704 during the second period, thus no significant difference existed in numbers of strains isolated in the two periods. 2. Among the 34 species to which the 4,704 strains were classified into, Pseudomonas aeruginosa comprised 68.4%, Stenotrophomonas maltophilia 6.9%, Acinetobacter baumannii 5.6%, Burkholderia cepacia 3.1%, Acinetobacter Iwoffii 2.6%, Alcaligenes xylosoxidans subsp. xylosoxidans 2.4%, Flavobacterium indologenes 1.7%, Pseudomonas putida 1.1%, Acinetobacter junii 1.1% and Moraxella subgenus Moraxella lacunata 0.9%. When these frequencies of isolation were compared with those in the first period, it was found that B. cepacia decreased significantly (P < 0.01) and that S. maltophilia increased significantly (P < 0.001). 3. MIC determinations revealed multiple drug resistance strains in many different species of bacteria. Minocycline, however, were active against many such strains, and ofloxacin was found to have strong antibacterial activity against some strains.

Anti-Bacterial Agents↗

PubMed1995

[Clinical and bacteriological effects of cefetamet pivoxil against community-acquired respiratory tract infections].

We investigated clinical and bacteriological effects of cefetamet pivoxil (CEMT-PI) in community-acquired respiratory tract infections and obtained the following findings. 1. Of the 420 respiratory tract infection cases that were treated with CEMT-PI according to a same protocol at a total of 42 institutions in Tokyo, Kanagawa-ken, Saitama-ken and Chiba-ken from February to the beginning of April 1994, 359 cases in which clinical evaluations were considered possible were selected as the subjects of the clinical study. Regarding genders of patients, slightly more females (56.3%) than males were included. Diagnoses given to these patients included laryngopharygealitis (60.7%), tonsillitis (14.2%) and acute bronchitis (13.6). Outpatients accounted for 94.4% of the subjects. 2. For the bacteriological study, a written material describing the method of collecting specimens, storage and transport in detail was distributed to the above mentioned institutions. The isolation and identification of suspected causative bacteria, determination of minimum inhibitory concentrations (MIC) and investigation of beta-lactamase production were conducted all together. Suspected causative bacteria were detected from 238 (66.3%) out of the 359 cases. They included 85 strains of Haemophilus influenzae, 76 strains of Streptococcus pneumoniae, 20 strains of Streptococcus pyogenes and 17 strains of Moraxella subgenus Branhamella catarrhalis. 3. Clinical efficacy rates (the ratio of those excellent+good) among those who were treated with 1 CEMT-PI tablet (194 mg, titer) twice a day was 76.5% and among those who were given 2 tablets twice a day was 87.4%. The improvement rate of the latter was higher at a significant level of P < 0.05. 4. The clinical efficacies classified by suspected causative bacteria (single bacterium) were 93.3% against M.(B.) catarrhalis, 91.7% against beta-streptococci, 87.1% against H. influenzae and 78.4% against S. pneumoniae, etc. Though 7 (9.2%) of the 76 strains of S. pneumoniae were benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP), the bacteriological efficacy was assessed either excellent or good in all of the 7 patients from whom PISP were detected. The clinical efficacy was assessed 100.0% in those from which a plural number of bacteria were detected. The 13 cases from which small numbers of Staphylococcus aureus was detected with other bacterium were also included in these cases.

Administration, Oral↗

PubMed1995

[Antibacterial activities of cefmenoxime against recent fresh clinical isolates from patients in sinusitis].

In order to evaluate antimicrobial activity of cefmenoxime (CMX), minimum inhibitory concentrations (MICs) of CMX and control drugs were determined against clinical isolates from patients of sinusitis that were obtained in our laboratory from October of 1993 to March of 1994. The results are summarized as follows; 1. CMX showed strong antimicrobial activities against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella subgenus Branhamella catarrhalis that were 3 major aerobic bacteria from sinusitis. Antimicrobial activities of CMX against benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP) and PCG-resistant S. pneumoniae (PRSP) were stronger than those of ampicillin (ABPC), and these strong activities suggested that CMX might have strong antimicrobial activities against beta-lactamase producing H. influenzae and M. (B.) catarrhalis. 2. Antimicrobial activities of CMX against microaerophiles, Streptococcus constellatus, Streptococcus intermedius and Gemella morbillorum and against Peptostreptococcus spp., from chronic sinusitis and odontogenic maxillary sinusitis, were stronger than those of most of the control drugs. 3. The MIC90's of CMX against isolates from patients of sinusitis were < or = 0.025-0.39 micrograms/ml. These values were lower than transitional concentrations in mucous membrane of maxillary sinus obtained when "1% CMX nasal solution" was used with nebulizer. It appears likely that sufficient concentrations exceeding MICs against main organisms would be obtained by nebulizer treatment using CMX nasal solution.

Cefmenoxime↗

PubMed1995

[Detection of bacteria in urine using dip-slides (1). Possible occurrence of false-negative results when dip-slides are used for urine containing antibacterial agents].

Dip-slides are used as semiquantitative microbial sampling devices that are simple to use in routine testing of urine to detect the presence of bacteria, and are recommended for use in "Standard evaluation of drug efficacy in UTI". Bacterial growth on currently available dip-slides, however, may conceivably be influenced by the presence of antibacterial agents in urine. We studied clinical performance of, and effects of antibacterial agents on, such dip-slides, using two types of dip-slides, URICULTE and DIASLIDE, both of which are newly developed urine culture devices. The quantitative conventional culture method was also used as the control. 1. When single species of bacteria are present in urine specimens of patients, results obtained using URICULTE and DIASLIDE agreed very well, and they, in turn agreed well with results obtained using the quantitative, conventional culture method, also. 2. When urine specimens were spiked with Gram-negative rods and Gram-positive cocci together, URICULTE fail to provide quantitative results because colonies were not well separated and confluent growth often resulted because of a large sample volume this device employs. DIASLIDE which used a smaller amount of sample, on the other hand, provided quantitative results with adequate separation of colonies. 3. When three antibacterial agents were added to urine specimens that were spiked with bacteria, DIASLIDE produced significantly higher numbers of colonies than URICULTE. The difference probably are due to the difference in volumes of specimens used in the two devices, the former device employs approximately 1/100 as much volume of specimen as the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1995

[Antibacterial activities of fosfomycin against recent clinical isolates from patients of otitis media and otitis externa].

Clinical isolates from patients with otitis media and/or otitis externa were collected at otorhinology clinics nationwide and sent to us during 1989, 1991 and 1993. Minimum inhibitory concentrations (MICs) of fosfomycin (FOM) and of reference drugs against these strains were determined to investigate year-to-year antibacterial activity of FOM. A comparative analysis of the results revealed trends described below. 1. The MIC90 of FOM against Staphylococcus aureus subsp. aureus increased 4 times by 1993 as compared to those measured for strains isolated in 1984 and 1985, when FOM for otic use was under development. This was thought to be due to the recent increase in the detection frequency of methicillin-resistant S. aureus (MRSA) which is also resistant to FOM. 2. No annual changes were seen for MIC distribution of FOM against Proteus group and Pseudomonas aeruginosa. 3. Since there was no large annual change in the antibacterial activity of FOM against recent clinical isolates obtained from patients with otitis media and/or otitis externa, FOM may be considered as one of the useful drugs even now, in the mid-1990's.

Drug Resistance, Microbial↗

PubMed1995

[Beta-lactamase production of clinically isolated bacteria].

We examined beta-lactamase productions by clinically isolated strains of bacteria. The results were as follows; 1. It appears that beta-lactamases produced by strains of five species of Staphylococcus spp. are mostly penicillinase (90%). Source of beta-lactamase producing strains of Haemophilus influenzae (23%) and all of Moraxella subgenus Branhamella catarrhalis: strains (100%) are "High & Low producer" strains. 2. A large proportion of beta-lactamase producing strains of Enterobacteriaceae and Bacteroides fragilis group appeared to be "High producer" 3. beta-lactamase producing abilities are different among glucose non-fermentative Gram-negative rods. It appears that some of the strains appeared to be "High producers".

Bacteria↗