Biomedical subjects

R Ishihara

Publications and source records attributed to R Ishihara.

At least 127 records · Page 7Linked to original sources

PubMed1991

[Combined antibacterial activity of aztreonam and clindamycin against clinically isolated strains].

It has been reported in some studies that the combination of aztreonam (AZT) and clindamycin (CLDM) have high clinical effectiveness in the treatment of intractable infections. We, therefore, studied combined in vitro antibacterial activity of these 2 compounds using many freshly isolated strains. 1. AZT and CLDM in combination had synergistic effects on Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Haemophilus influenzae, which are sensitive or quasi-sensitive to CLDM, in the presence of CLDM at MIC or sub-MIC. 2. For Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter cloacae, Serratia marcescens, and Pseudomonas aeruginosa, which are not sensitive to CLDM, the 2 drugs in combination showed synergistic effects on some species and additive or slightly additive effects on most species in the presence of CLDM at those concentrations which are usually maintained in blood. 3. The 2 drugs showed no antagonism.

Aztreonam↗

PubMed1991

[Bacteriological study on fosfomycin against organisms clinically isolated from paranasal sinusitis].

Multi-center bacteriological and clinical studies on fosfomycin (FOM) nasal solution were performed in subjects with paranasal sinusitis from January, 1988 to May, 1990. In these studies, we were exclusively responsible for bacterial isolation from clinical sources, bacterial identification and the determination of drug susceptibility. Before local administration of FOM nasal solution, many strains of various bacterial species were isolated from sources totalling 396 cases involved in phase II clinical studies, dose-finding and open clinical studies. From antibacterial activities of FOM against those isolates, we obtained the following conclusions. 1. Among the 447 isolates, Streptococcus spp. occupied 25.7%, Staphylococcus spp. 21.7% and anaerobic Gram-positive cocci (GPC) 13.6%, showing high detection frequency of aerobic and anaerobic GPC. Next to these, Haemophilus influenzae, Pseudomonas aeruginosa, Klebsiella spp. and Branhamella catarrhalis also were often obtained. 2. After exclusion of possibly contaminating strains which might have entered into cultures at samplings or transfers, the MIC50 and the MIC80 of FOM against the remaining 354 isolates were determined to be 12.5 and 25 micrograms/ml, respectively, indicating that local use of FOM would be fully effective to eradicate most of the bacteria. 3. FOM nasal solution showed sufficient eradication efficacy against most clinical isolates of possible causative organisms of paranasal sinusitis, and appeared to be useful as a topical preparation for the treatment of this disease.

Administration, Intranasal↗

PubMed1991

[Antimicrobial activity of cefpiramide to fresh clinical isolates].

In the subjects of 835 strains of 37 clinically isolated microbial strains, which were separated and identified among materials collected from patients with various infections and which were sent from medical therapeutic institutions throughout Japan in 1990, for the purpose of examining the antimicrobial activity of cefpiramide (CPM), its minimum inhibitory concentration (MIC), together with those of other cephem antibiotics, was determined, and the following conclusions were obtained. 1. Microbial strains in which no CPM-resistant strains emerged were Streptococcus pyogenes, Streptococcus pneumoniae and Anaerobic Gram-positive cocci. 2. In comparison with reports by many researchers at the former half of the 1980s, microbial stains suggesting an increase in resistance to CPM were Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas cepacia, Pseudomonas putida, Acinetobacter calcoaceticus, and Haemophilus influenzae, but also in other microbial strains the resistance to CPM was observed in high ratios. 3. Among strains used in the test, methicillin-resistant S. aureus, cephamycin and oxime type cephalosporin-resistant Gram-negative bacilli of Enterobacteriaceae, and new quinolone-resistant microbes were observed in high ratios; therefore, it was considered that CPM could not exert sufficient antimicrobial activities to these strains because of many resistant strains being complicated among these "CPM-resistant strains". 4. It was discussed that "the resistance mechanism observed throughout beta-lactam drugs as a while and the study themes in the dimension including social circumstances where resistant strains emerged", as pointed out by the authors in 1989, increased the significance of these days in the evaluation of timecourse changes in microbes resistant to specific drugs including CPM. 5. There are many unfavorable conditions in the antimicrobial activities of CPM to clinically isolated strains in recent years. However, it was jointly confirmed that CPM maintained effective antimicrobial activities to the majority of clinically isolated strains. Furthermore, when it was additionally considered that CPM was one of not many cephem drugs having persistent blood levels, a conclusion was drawn that CPM was one of clincally useful cephem drugs even at present.

Anti-Bacterial Agents↗

PubMed1991

[Antibacterial activities of ofloxacin against recent isolates from patients with community-acquired infections].

In order to survey antibacterial activities of ofloxacin (OFLX) against 1,440 bacterial strains isolated from patients with community-acquired infections in 1987 and 1990, minimum inhibitory concentrations (MICs) of the drug as well as those of other new quinolones and oral cephems were determined. The following conclusions were reached. 1. Comparison of the MIC distribution for strains isolated in 1987 with those in 1990 suggested a tendency toward an increase in the frequency of OFLX-resistant isolates with the passage of time of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Citrobacter spp., Klebsiella ssp., Enterobacter spp., Proteus vulgaris, Morganella morganii, Providencia spp., and Acinetobacter calcoaceticus. Most common elevations of MIC values against these bacteria were observed in MIC80 and MIC90 values, while no significant alteration was observed in MIC50 values. However, MIC50's of OFLX against Serratia marcescens and Pseudomonas aeruginosa were relatively high for strains isolated in both 1987 and 1990. Most of the OFLX-resistant strains of S. aureus seemed to be methicillin-resistant (MRSA). Furthermore, MIC80 of OFLX against coagulase-negative staphylococci was high in strains isolated in both 1987 and 1990. 2. Susceptibility of Streptococcus spp. was evaluated only in strains isolated in 1990. The results were comparable to those reported by others in the early 1980s. 3. Bacteria which showed no or infrequent emergence of OFLX-resistant strains even in 1990 were Proteus mirabilis, Haemophilus influenzae, Neisseria gonorrhoeae, Campylobacter spp. and Peptostreptococcus spp. 4. Recently isolated strains from patients with community-acquired infections showed a tendency toward an increase of the frequency of OFLX-resistant strains among many bacteria. However, the bacteria which contained high percentages of OFLX-resistant strains except for MRSA were so-called less-virulent bacteria, and in the other bacteria elevations of MIC values were only observed in MIC80 and MIC90. These results suggested that OFLX preserved a potent antibacterial activity against bacteria which were major causative pathogens in community-acquired infections.

Bacteria↗

PubMed1991

[Antibacterial activity of ciprofloxacin against fresh clinical isolates from superficial suppurative foci].

The minimum inhibitory concentrations (MICs) of 5 drugs (ciprofloxacin (CPFX), and 4 drugs used as standard) were determined to investigate antibacterial potencies of CPFX against bacterial strains isolated in 1989 from superficial suppurative foci. The clinical isolates tested included 375 strains from 11 aerobic bacterial species, and 50 strains from 2 anerobic bacterial genera (group) for a total of 425 isolates. Interpreting MIC level distributions of these drugs as the expression of antibacterial potencies, the results are as follows. 1. When activities of new-quinolone antibiotics were tested, we found that, CPFX expressed far superior antibacterial potency to ofloxacin (OFLX) and norfloxacin (NFLX) against coagulase-negative staphylococci, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Pseudomonas aeruginosa and Peptostreptococcus spp., although the activity of CPFX against Bacteroides fragilis group was weaker than that of OFLX, and CPFX had similar activity against Staphylococcus aureus to OFLX. 2. In comparison to beta-lactam antibiotics, CPFX was inferior to amoxicillin (AMPC) against E. faecalis and inferior to AMPC and cefaclor (CCL) against Peptostreptococcus spp. Against all other bacterial species, however, CPFX expressed superior antibacterial potency to AMPC and CCL. 3. Scattered findings of low sensitivity or resistance to CPFX were observed among the S. aureus, E. faecalis, E. faecium, P. vulgaris, M. morganii, P. aeruginosa and B. fragilis (group) species, but with an exception of E. faecium, the incidence of resistance strains was low.

Amoxicillin↗

PubMed1990

Distribution patterns of dendrites in motor neuron pools of lumbosacral spinal cord of the chicken.

The morphology of dendritic trees (dendroarchitecture) of motor neurons innervating specific hindlimb muscles (motoneuron pools, MNP) was studied in the chick spinal cord. Motoneurons were labelled by intramuscular injections of horseradish peroxidase conjugated with cholera toxin subunit B. MNPs of posterior iliotibial and femorotibial muscles were located at the dorsolateral part of lateral motor column of lumbosacral segments (LS) 1-4 and 1-3, respectively. Although the dendritic profiles of femorotibialis motoneurons were fewer than those of posterior iliotibialis, these two MNPs had a similar distribution pattern of dendrites. Dendritic profiles were about equally distributed in the gray and white matter. Dendrites from the MNP of posterior iliotibialis radiated in all directions. A large number of dendrites penetrated into the white matter, and some even reached to the subpial regions of the lateral funiculus. One array of dendrites that projected dorsomedialwards extended to the base of the posterior horn. MNPs of both the iliofibularis (LS 4-7) and caudilioflexorius (LS 6-8) had dendritic trees with similar distribution patterns. There were two main arrays of dendritic extensions; one along the dorsal, and another along the ventral border of the lateral motor column. Dendrites from the iliofibularis and caudilioflexorius motoneurons were located more frequently in the white matter than in the gray matter. A large number of dendrites extended in all directions from the MNP of the adductor muscle, which was located in the medial region of lateral motor column of LS 1-2. The distribution of dendrites from a few other MNPs was also examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Identification of early developing axon projections from spinal interneurons in the chick embryo with a neuron specific beta-tubulin antibody: evidence for a new 'pioneer' pathway in the spinal cord.

The early development of interneurons in the chick embryo spinal cord was studied using a monoclonal antibody against a neuron-specific beta-tubulin isoform. Early developing interneurons were divided into two cell groups on the basis of their location and the pattern of growth of their axons. One group is composed of cells that establish a primitive longitudinal pathway (PL-cells), whereas the other group contains cells constituting a circumferential pathway (C-cells). The onset of axonal development in both cell groups occurs at stage (st.) 15 (embryonic day, (E), 2) in the branchial segments, which is prior to axonogenesis of motoneurons. PL-cells develop in the region between the floor plate and the motoneuron nucleus. Their axons are the first neuronal processes ('pioneer axons') to arrive in the ventrolateral marginal zone and they project both rostrally and caudally to establish a primitive longitudinal association pathway at the ventrolateral surface of the neural tube. This pathway is formed before axons of C-cells arrive in the ventrolateral region. The first C-cells are initially located in the most dorsal portion of the neural tube, whereas later appearing C-cells are also located in both intermediate and ventral regions of the neural tube. The axons of C-cells project ventrally, without fasciculating, along the lateral border of the neural tube. Some of their axons enter the ipsilateral ventrolateral longitudinal pathway at st. 17. We often observed apparent contacts and interactions between preexisting axons of PL-cells and newly arriving axons of C-cells. The axons of commissural C-cells first enter the floor plate at st. 17 and cross the midline at st. 18. Axons of C cells begin to join the contralateral ventrolateral longitudinal pathway at st. 18+ to st. 19. In the floor plate region, contacts between growth cones and axons were often observed. However, axons in the floor plate at these stages were not fasciculated. These observations establish the timing and pattern of growth of axons from two specific populations of early developing interneurons in the chick spinal cord. Additionally, we have identified an early and apparently previously undescribed 'pioneer' pathway that constitutes the first longitudinal pathway in the chick spinal cord.

Animals↗

PubMed1990

[Study on susceptibilities of freshly isolated strains to macrolide antibiotics].

Macrolide (ML) susceptibilities of clinically isolated bacteria obtained freshly during 1989 were determined and year to year differences in ML-resistances of the clinical isolates in our laboratory were examined with epidemiological consideration in mind. 1. The distribution of minimum inhibitory concentrations (MICs) of MLs against isolates of Staphylococcus aureus showed 2 peaks, one peak representing S. aureus isolates susceptible to MLs and the other peak representing those resistant to MLs. Proportions of resistant isolates to various MLs were 36% to erythromycin, 24% each to kitasamycin, josamycin, midecamycin and midecamycin acetate. MICs of rokitamycin (RKM), however, distributed themselves into 3 peaks of less than or equal to 0.39 micrograms/ml (76%), 1.56-3.13 micrograms/ml (12%) and greater than or equal to 100 micrograms/ml (12%). Staphylococcus spp. including Staphylococcus epidermidis showed different resistance characteristics to 14-membered ring MLs and to 16-membered ring MLs. Further, the proportion of resistant organisms to RKM was the smallest among proportions of resistant organisms to various 16-membered ring MLs tested. These differences in proportions of resistant organisms to different MLs may have resulted from differences in resistance induction activities of different MLs. The above described ratios of resistant organisms to MLs among S. aureus did not vary since 1975 among clinical isolates tested in our laboratory. 2. Four per cent (4%) of Streptococcus pyogenes isolates were MLs resistant, and 18% of Streptococcus pneumoniae isolates were resistant to MLs. Among the isolates tested in our laboratory since 1985, resistant isolates of S. pyogenes are clearly decreasing and those of S. pneumoniae seem to be increasing.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1990

[Antimicrobial activities of gentamicin against fresh clinical isolates].

Antimicrobial activities of gentamicin (GM), compared with activities of other aminoglycosides (AGs) and beta-lactam antibiotics, were studied against clinical isolates obtained during a period of July-December 1989. 1. GM-resistant strains were noted in 24% of Staphylococcus aureus, 12% of Enterobacter spp., 24% of Serratia marcescens, 7% of Morganella morganii and 26% of Pseudomonas aeruginosa, but no GM-resistant strains were observed among isolates of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Proteus vulgaris. 2. A majority of GM-resistant strains of S. aureus were methicillin-resistant S. aureus (MRSA) and a large number of GM-resistant strains of Enterobacter spp. was also resistant to new quinolones. GM showed, however, strong antimicrobial activities against new quinolones-resistant strains of S. marcescens, M. morganii and P. aeruginosa. 3. Among all the isolates tested of S. marcescens, 24% were GM-resistant, 72% were tobramycin (TOB)-resistant, 86% were dibekacin (DKB)-resistant and 64% were amikacin (AMK)-resistant, hence the incidence of GM-resistant strains was the lowest. This tendency was also observed with P. vulgaris. However, among P. aeruginosa, 26% were GM-resistant, 14% TOB-resistant, 18% DKB-resistant and 22% AMK-resistant, thus the incidence rate for GM-resistance was somewhat higher. These results suggest that different AGs-modification enzymes were produced by various clinical isolates under the present condition. 4. Comparing the ratio of GM-resistant strains in the present study with those in 1980 and 1983, the ratio increased among S. aureus, while decreases were observed among Enterobacter spp., S. marcescens, P. vulgaris and P. aeruginosa, indicating that a unilateral tendency of increases in GM-resistant strains did not exist among clinical isolates over the years.

Anti-Bacterial Agents↗

PubMed1990

[Synergy between sulbactam and ampicillin or cefoperazone in antimicrobial activity against beta-lactamase producing microorganisms. Results with the use of microdilution broth method].

Antimicrobial activities of sulbactam (SBT) with ampicillin (ABPC) or with cefoperazone (CPZ), in other words, the effects of SBT, an beta-lactamase inhibitor, against beta-lactamase producing strains of clinical isolates, were studied using microdilution broth method. 1. beta-Lactamase producing strains such as Staphylococcus aureus, Branhamella catarrhalis, Haemophilus influenzae, Escherichia coli and Klebsiella pneumoniae decompose benzylpenicillin (PCG) which is one of substrates of the acid-metry disc method and show a strong reaction, while they do not decompose cefazolin (CEZ), another substrate, showing no or weak reaction. Thus, it is suspected that beta-lactamases produced by these organisms are mainly penicillinase (PCase). MIC-distributions of ABPC and CPZ against these clinical isolates which seemed to produce PCase shifted to lower MIC ranges with MIC's reduced to 1/4 or below when 0.025 to 0.39 microgram/ml of SBT was added. 2. It appears that beta-lactamase produced by Proteus vulgaris may be oxyiminocephalosporinase (CXase), because P. vulgaris showed strong reaction on CEZ, but moderate reaction on PCG in the acid-metry disc method. MIC-distribution of ABPC and CPZ against P. vulgaris shifted to a lower range with MIC's of 1/4 or below when 0.20 to 0.39 microgram/ml of SBT was added. 3. All the test strains of Pseudomonas aeruginosa showed strong reaction on CEZ but only 56% of the test strains showed reaction on PCG. It appears that the beta-lactamases which showed strong reaction on CEZ is cephalosporinase and is encoded in chromosome, while those beta-lactamase that showed strong reaction on PCG is encoded in a plasmid which was acquired secondarily by P. aeruginosa. MIC-distribution of CPZ against P. aeruginosa shifted to a lower range with MIC values of 1/2 or below with the addition of SBT at 1.56 micrograms/ml. 4. It appears that the synergy of SBT with ABPC or with CPZ against the PCase or CXase producing strains may occur in the presence of SBT at a concentration far less than that reported previously.

Ampicillin↗

PubMed1990

[A study of five cases of traumatic diaphragmatic rupture].

During the last 5 years, 5 cases of traumatic diaphragmatic rupture were surgically treated. These cases were reported and the literature concerning traumatic diaphragmatic hernia in the last one decade in Japan, including 80 cases was studied. The purpose of this study is to discuss the most important early diagnostic tools and to consider the choice of incision and approach. The following two results were gotten. (1) Plain chest X-ray, computed tomography and ultrasonography were the most valuable diagnostic tools. (2) The choice of incision and approach depends on the stage at which the rupture is recognized (early or late), the site of rupture and associate injuries.

Adult↗

PubMed1990

[Annual changes in susceptibility of clinical isolates to midecamycin acetate].

To investigate annual changes in the susceptibility of clinical isolates to midecamycin acetate (MDM-AC), minimum inhibitory concentrations (MICs) of MDM-AC were determined for clinical isolates obtained from outpatients since 1985. MDM-AC-resistant strains of Staphylococcus spp. and Streptococcus spp. have shown similar degrees of resistance to midecamycin and josamycin. Regarding this as macrolide resistance, proportions of macrolide-resistant strains tended to increase for Staphylococcus aureus and Streptococcus pneumoniae but to decrease for Streptococcus pyogenes. 1. For S. aureus, 8% of the strains isolated in 1985, 20% in 1987 and 20% in 1989 were macrolide-resistant. Of these macrolide-resistant strains, 70% or more in 1987 and 80% or more in 1989 were methicillin-resistant S. aureus (MRSA). 2. For S. pneumoniae, 8% of the strains isolated in 1985, 12% in 1987 and 12% in 1989 were macrolide-resistant, indicating a tendency for resistant strains to increase annually. 3. For S. pyogenes, 8% of the strains isolated in 1985, 4% in 1987 and 0% in 1989 were macrolide-resistant, showing a decreasing tendency. 4. MDM-AC is still thought to be a clinically useful antibacterial agent because it still shows antibacterial activity against 80% or more of Gram-positive cocci clinically isolated in recent years and a low degree of induction of macrolide resistance in Staphylococcus spp.

Bacterial Infections↗

PubMed1989

[A case of intractable hepatic hydrothorax treated by pleuro-venous shunt].

A 64-year-old woman with Idiopathic Portal Hypertension was hospitalized for severe respiratory distress. Chest X-ray film showed a massive pleural effusion in the right hemithorax. Though repeated thoracentesis was performed, the patient was suffering from dyspnea frequently. A pleurovenous shunt was inserted. Follow up chest X-ray films showed resolution of pleural effusion and the patient remained free of symptoms. Two months after the placement of the shunt pleural effusion again began to develop with systemic edema caused by development of chronic renal failure. Reduction of effusion was obtained by hemodialysis. Pleurovenous shunting may provide satisfactory palliation for intractable pleural effusions.

Female↗

PubMed1988

Differential innervation of specific motor neuron pools by serotoninergic fibers in the chick spinal cord.

A new technique in which cholera toxin subunit B conjugated to horseradish peroxidase is injected in chick muscles followed by perfusion with Zamboni's fixative for serotonin immunocytochemistry allows one to visualize immunoreactive fibers and retrogradely labelled motoneurons in alternate sections. Using these procedures, we have found that there is a differential innervation by serotoninergic fibers of motoneuron pools that project to specific muscles or muscle groups. Dense clusters of serotonin-positive fibers were located in the motoneuron pools of extensors of the hip joint consisting of the lateral iliotibialis, ischioflexorius, iliofibularis, accessorius and caudilioflexorius muscles.

Animals↗

PubMed1988