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Biomedical subjects

M Shibata

Publications and source records attributed to M Shibata.

At least 685 records · Page 38Linked to original sources
PubMed1985

Alahopcin, a new dipeptide antibiotic produced by Streptomyces albulus subsp. ochragerus subsp. nov.

An actinomycete strain No. B-52653 was found to produce an antibiotic selectively active against the in vitro antibiotic resistant mutant of Staphylococcus aureus. Based on taxonomic studies, the name Streptomyces albulus subsp. ochragerus subsp. nov. is proposed for the strain. The microorganism produced two kinds of antibiotics; one identical with gougerotin, the other an amphoteric water soluble dipeptide containing L-alanine. The latter has the molecular formula C9H15N3O6 and is named alahopcin. It has a broad antibacterial spectrum and a synergistic effect with some other antibiotics against some antibiotic resistant staphylococci. Alahopcin has a low toxicity and was effective against experimental infections in mice caused by Staphylococcus aureus.

Animals↗
PubMed1985

[Experimental and clinical studies on BRL 25000 (clavulanic acid-amoxicillin) in the pediatric field].

Fundamental and clinical studies on BRL 25000 granules were carried out in the pediatric field. BRL 25000 is a formulation comprising 1 part of clavulanic acid (CVA) and 2 parts of amoxicillin (AMPC). The MICs of BRL 25000 and AMPC were assessed against 24 clinically isolated strains of S. aureus (including 23 beta-lactamase producing strains), 22 S. pyogenes, 20 E. coli (8 beta-lactamase producing strains), 24 K. pneumoniae (24 beta-lactamase producing strains), 20 H. influenzae (6 beta-lactamase producing strains). BRL 25000 showed MIC80 (cumulatively 80% of strains were inhibited) at 6.25 micrograms/ml against S. aureus, less than or equal to 0.10 micrograms/ml against inst S. pyogenes, 12.5 micrograms/ml against E. coli, 6.25 micrograms/ml against K. pneumoniae and 0.39 micrograms/ml against H. influenzae. BRL 25000 showed no improvement in MIC terms against beta-lactamase nonproducing strains compared with AMPC. However, BRL 25000 was markedly more effective against beta-lactamase producing strains. Thus BRL 25000 was up to 8 fold more active against S. aureus, 2 to 64 fold against E. coli, 4 to 128 fold against K. pneumoniae, 4 to 16 fold against H. influenzae than AMPC. Following oral administration of BRL 25000 granules (at a dose level of 12.5 mg/kg) to 2 children aged 9 and 11 years, the mean peak serum concentrations of AMPC and CVA were 8.33 +/- 2.43 micrograms/ml and 4.44 +/- 1.65 micrograms/ml respectively 1 hour after dosing. The half-lives of AMPC and CVA were 1.35 +/- 0.42 hours and 0.91 +/- 0.05 hour, respectively. The urinary excretion was 48.21 +/- 3.83% for AMPC and 16.90 +/- 7.06% for CVA in the first 6 hours after administration. In clinical studies, 23 pediatric patients aged 2 months to 12 years with bacterial infections were treated with BRL 25000 granules and the clinical effectiveness, bacteriological response and side effects were evaluated. The clinical response was assessed in 23 cases, 3 with acute rhinitis, 6 with acute purulent tonsillitis, 5 with acute bronchitis, 4 with acute pneumonia, 3 with impetigo, 1 with furunculosis and 1 with periproctal abscess. Results were excellent in 13 cases, good in 7, fair in 3 and hence the efficacy rate (excellent and good cases) was 87.0% (20/23). In particular the clinical response in 9 cases with infections due to beta-lactamase producing organisms was excellent in 6, good in 2, fair in 1 and the efficacy rate was 88.9% (8/9).(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗
PubMed1985

[Fundamental and clinical studies on aspoxicillin in the pediatric field].

Fundamental and clinical studies of aspoxicillin (ASPC, TA-058), a new penicillin antibiotic, were performed in pediatric field. Antimicrobial activity MIC of ASPC was compared with that of piperacillin (PIPC), ampicillin (ABPC) and carbenicillin (CBPC) for clinical isolates of S. aureus (24 strains), S. pyogenes (22 strains), H. influenzae (18 strains), E. coli (21 strains) and K. pneumoniae (23 strains). MIC of ASPC against S. pyogenes was distributed in less than 0.39 microgram/ml and this numerical value of MIC was very superior. MIC distributions of ASPC against S. aureus, H. influenzae and E. coli had 2 peaks respectively. It was presumed that the results are due to an existence of beta-lactamase producing strains. The sensitive strains in those were distributed in less than 1.56-12.5, less than or equal to 0.10 and 0.78-3.13 micrograms/ml, respectively, and those numerical value of MIC was superior. While against K. pneumoniae, all strains were distributed in more than 12.5 micrograms/ml and the antimicrobial activity of ASPC was very inferior. ASPC was as active as PIPC and ABPC against S. pyogenes, but more active then CBPC, ASPC was less active against S. aureus than PIPC and ABPC, but more active than CBPC. And ASPC was less active against H. influenzae and E. coli than PIPC, but more active than ABPC and CBPC. Against K. pneumoniae, strains that showed somewhat low numerical value of MIC at only PIPC were observed, but antimicrobial activities of ABPC and CBPC, as well as ASPC were very inferior. Absorption and excretion Serum level and urinary excretion of ASPC in 6 pediatric patients of 4 months to 12 years of age after one shot intravenous injection of 20 mg/kg were examined. The serum mean levels were 51.7 micrograms/ml at 1/4 hour, 38.2 micrograms/ml at 1/2 hour, 22.9 micrograms/ml at 1 hour, 3.0 micrograms/ml at 4 hours and 1.0 microgram/ml at 6 hours after injection, respectively. The mean half-life of serum level was 1.03 hours. The mean urinary levels were 4,646 micrograms/ml for 0-2 hours, 1,773 micrograms/ml for 2-4 hours and 299 micrograms/ml for 4-6 hours. The mean urinary recovery rate within 6 hours after injection was 64.7%. Clinical studies In order to evaluate clinical response, bacteriological response and side effects, ASPC was applied to 28 cases, i.e., 5 cases of acute purulent tonsillitis, 2 cases of acute purulent otitis media, 2 cases of acute bronchitis and 19 cases of acute pneumonia.(ABSTRACT TRUNCATED AT 400 WORDS)

Amoxicillin↗
PubMed1985

[Clinical studies of ceftizoxime suppositories in respiratory tract infections and urinary tract infections in children].

A fundamental and clinical study of ceftizoxime (CZX) suppositories was performed in pre-school and school-age children. The average time courses of CZX serum and urinary concentrations after administration of CZX suppository 250 mg (i.e. per kg body weight doses of 8.3-10.9 mg) to 4 school-age children were as follows. Serum concentrations: 6.1 micrograms/ml at 15 minutes, 6.3 micrograms/ml at 30 minutes, 3.8 micrograms/ml at 1 hour, 1.7 microgram/ml at 2 hours, 0.5 microgram/ml at 4 hours and 0.2 microgram/ml at 6 hours with a biological half-life of 1.43 hours. Urinary concentrations: 885 micrograms/ml for 0-2 hours, 209 micrograms/ml for 2-4 hours and 112 micrograms/ml for 4-6 hours with an average 6-hour urinary recovery rate of 25.6%. The clinical and biological effectiveness and adverse reactions were studied in 11 infants and school-age children afflicted with various infections (acute purulent tonsillitis, 1; acute bronchitis, 3; acute pneumonia, 4; and UTI, 3). The clinical responsiveness was "excellent" in 8, "good" in 2, and "failure" was recorded in 1, with an overall efficacy of 90.9% inclusive of "excellent" and "good". The microbiological effectiveness of CZX suppositories on presumed pathogenic organisms comprising 4 strains of H. influenzae, 1 strain of H. parainfluenzae, and 3 strains of E. coli was satisfactory, as evidenced by the substantially high eradication rate of 87.5%. The only organism that survived CZX suppository treatment was 1 strain of H. influenzae which however was greatly decreased. The only side effect was diarrhea in 1 patient, which however did not necessitate withdrawal of the drug. The only laboratory test abnormality was GOT and GPT elevation in 1 patient which was normalized within 8 days. In conclusion, CZX suppositories were found to be efficacious and safe for treatment of bacterial infections in children.

Bacteria↗
PubMed1985

[Fundamental and clinical studies on cefminox in the field of pediatrics].

A new antibiotic of cephamycin group, cefminox (CMNX, MT-141) was studied both fundamentally and clinically in the field of pediatrics. The minimum inhibitory concentrations (MIC) of CMNX for clinical isolates including 24 strains of S. aureus, 15 strains of S. pyogenes, 21 strains of H. influenzae, 24 strains of E. coli, 22 strains of K. pneumoniae and 22 strains of P. mirabilis were determined and compared to those of cefmetazole (CMZ), latamoxef (LMOX), cefotaxime (CTX), cefoperazone (CPZ) and cefazolin (CEZ). The MIC80 (80% MIC) values of CMNX for H. influenzae, E. coli, K. pneumoniae and P. mirabilis were 1.56, 1.56, 0.39 and 1.56 micrograms/ml, respectively. When compared to antibacterial activities of the control drugs, the activity of CMNX was inferior to those of CTX and LMOX but superior to those of CMZ and CEZ. On the other hand, MIC80 values of CMNX for S. pyogenes and S. aureus were 6.25 and 12.5 micrograms/ml, the activities being inferior to all of CMZ, CTX, LMOX, CPZ and CEZ used as the control drugs. In 3 pediatric patients of 9 to 12 years old, 20 mg/kg of CMNX was given intravenously as one shot and serum and urinary concentrations were determined. The mean serum concentrations in these 3 cases were 124 micrograms/ml, 102 micrograms/ml, 74.0 micrograms/ml, 47.9 micrograms/ml, 20.4 micrograms/ml, 9.2 micrograms/ml and 4.3 micrograms/ml at 1/4, 1/2, 1, 2, 4, 6 and 8 hours, respectively, with a half-life of 1.83 hours. The mean urinary concentrations were 1,968 micrograms/ml at 0 approximately 2 hours, 1,205 micrograms/ml at 2 approximately 4 hours, 761 micrograms/ml at 4 approximately 6 hours and 409 micrograms/ml at 6 approximately 8 hours, with 65.4% of the drug dosed recovered from the urine within the first 8 hours on an average. CMNX was used in the treatment of 22 clinical cases including 3 cases of acute purulent tonsillitis, 3 cases of acute bronchitis, 9 cases of acute pneumonia, 5 cases of acute pyelonephritis and 2 cases of acute enteritis. Clinical results in 20 cases excluded of 2 cases of Mycoplasma pneumonia were rated as excellent in 19 cases and as good in 1 case, with an efficacy rate being 100% taking excellent and good cases as effective cases. Bacteriological results for 5 strains of H. influenzae, 1 strain of H. parainfluenzae, 5 strains of E. coli, 2 strains of K. oxytoca and 1 strain of S. pneumoniae revealed that disappearance was obtained for all strains but 1 strain of P. aeruginosa which persisted.(ABSTRACT TRUNCATED AT 400 WORDS)

Anti-Bacterial Agents↗
PubMed1985

[Fundamental and clinical studies on aztreonam in the pediatric field].

Fundamental and clinical studies on aztreonam (AZT), a new monobactam antibiotic, were performed in the pediatric field. The MICs of AZT were assessed against the clinically isolated strains in the pediatric infections. AZT showed an excellent antibacterial activity against Gram-negative bacteria, i.e., against E. coli (20 strains), K. pneumoniae (9), P. mirabilis (16), P. vulgaris (5), P. aeruginosa (10), S. typhimurium (4) and H. influenzae (11); the MICs of AZT against the above strains were less than 0.39 microgram/ml, 0.10 microgram/ml, 0.024 microgram/ml, 0.024 microgram/ml, 6.25 micrograms/ml, 0.10 microgram/ml and 0.10 microgram/ml, respectively. However, antibacterial activity of AZT against Gram-positive bacteria was inferior to that against Gram-negative bacteria, i.e., against the strains of S. aureus (16) and S. pyogenes (4), those MICs were more than 400 micrograms/ml and 3.13 micrograms/ml, respectively. Serum concentrations and urinary excretion of AZT were measured in 2 children aged 7 and 11 years after a single intravenous injection at the dose of 20 mg/kg. The mean serum concentration of AZT followed by the injection 62.5 micrograms/ml at 1/4 hour, 28.5 micrograms/ml at 1/2 hour, 16.5 micrograms/ml at 1 hour, 12.0 micrograms/ml at 2 hours, 3.6 micrograms/ml at 4 hours and 1.1 micrograms/ml at 6 hours, respectively. The mean half-life (beta-phase) was 1.24 hours. The mean urinary concentrations after the injection were 5,000 micrograms/ml in 0-2 hours, 1,650 micrograms/ml in 2-4 hours and 611 micrograms/ml in 4-6 hours and the mean urinary recovery rate up to 6 hours was 61.2%. These results in our studies were considered to be comparable with those reported in adults. In our clinical studies, AZT was administered to a total of 14 cases, i.e., acute pneumonia (4 cases), acute pyelonephritis (4), acute enteritis (5) and acute sppurative cholangitis (1). Clinical effect of AZT was excellent or good in 13 cases except fair in 1 case with acute enteritis and the efficacy rate (excellent and good) was 92.9%. With regard to bacteriological effect, all the strains of H. influenzae (3), E. coli (2), P. mirabilis (1) and P. vulgaris (1) were eradicated, but, S. typhimurium (4) was not eradicated. Neither side effect nor abnormal laboratory findings were observed during the study.

Age Factors↗
PubMed1984

Effects of leukocytic pyrogen and sodium salicylate on hypothalamic thermosensitive neurons in vitro.

The effects of leukocytic pyrogen and sodium salicylate (Sal) were studied on the single-unit activities of neurons in the preoptic and anterior hypothalamus (PO/AH) recorded in tissue slices in vitro. The pyrogen applied to the immediate vicinity of the recorded neurons decreased the firing rate of the majority of warm-sensitive neurons, but had no effect on the activities of thermally insensitive neurons. The pyrogen-induced inhibition of warm-sensitive neurons was reversibly blocked by local application of Sal. The results support the view that the pyretic and antipyretic effects of intrahypothalamic pyrogen and Sal are caused by their offsetting actions on the PO/AH thermosensitive neurons.

Animals↗
PubMed1984

Potential-derived point-charge model study of electrostatic interactions in DNA base components.

Ab initio electrostatic potentials obtained using STO-3G wavefunctions for guanine, cytosine, adenine, and thymine are used to calculate potential-derived (PD) point charges for these base components. Calculated PD point charges are used to estimate the electrostatic contributions to hydrogen-bonding and stacking interaction energies of ten sequence isomers of B-DNA. These estimates are in excellent agreement with the results of the more elaborate segmental multipole moment expansion technique.

Adenine↗
PubMed1984

Activity of hypothalamic thermosensitive neurons during cortical spreading depression in the rat.

Effects of single waves of cortical spreading depression (CSD) on unit activity of the ipsilateral preoptic and anterior hypothalamic (PO/AH) neurons were studied in urethane-anesthetized rats. When CSD entered the frontal cortex, the firing rate of the majority (85%, 22/26 units) of PO/AH warm-sensitive neurons decreased for 1.4-14.2 min and the remaining 4 neurons were unaffected. In contrast, 10 (77%) of the 13 cold-sensitive neurons increased their firing rates for 1.2-10.4 min after the CSD entrance of the frontal cortex. Of the remaining 3 neurons, two decreased their firing rates and one showed no change during CSD. Thirteen (76%) of the 17 thermally insensitive neurons were not affected by CSD, but the remaining 4 neurons decreased their firing rates slightly for about 1.4 min. The most critical cortical region responsible for the activity change of the PO/AH thermosensitive neurons during CSD was found to lie in the sulcal prefrontal cortex by observing the effect of a single CSD elicited separately from the occipital and the frontal cortex on the same PO/AH neurons (a double-CSD technique). The result, together with the previous ones on thermoregulatory responses during the frontal CSD, suggests that the sulcal prefrontal cortex exerts a tonic influence on the activity of the hypothalamic thermosensitive neurons and is involved in the central control of thermoregulation.

Animals↗
PubMed1984

Potential derived point charge model study of electrostatic interaction energies in some complexes of water with uracil, thymine, and cytosine.

Potential derived (PD) point charges and segmental multipole moments are calculated for water, uracil, thymine, and cytosine using STO-3G quality wave functions. The PD point charges are used to estimate the electrostatic interaction energies for a series of complexes of water with these nucleic acid bases. It is shown here that the results obtained using simple PD charge model is very similar to those obtained from more elaborate segmental multipole moment analysis.

Algorithms↗
PubMed1984

Long-term toxicity and carcinogenicity study of sodium o-phenylphenate in B6C3F1 mice.

Sodium o-phenylphenate (OPP-Na) was given at dietary levels of O (control), 0.5, 1.0 and 2.0% to groups of 50 male and 50 female mice for 96 wk, and all the animals were maintained without OPP-Na for a further 8 wk. Both sexes given 2% OPP-Na and females given 0.5% and 1% OPP-Na showed growth retardation. Serum alkaline phosphatase activity in OPP-Na treated females was significantly increased in a dose-related manner. There were no treatment-related effects on clinical signs, mortality, urinalyses, haematology or organ weights. The incidences of several non-neoplastic and neoplastic lesions achieved statistical significance but none was considered to be related to treatment. There were increased incidences of haemangiosarcomas of the liver in males given 1% and of hepatocellular carcinomas in 1 and 2% males, and haemangiomas and leiomyomas of the uterus, present in the controls, were absent or decreased in all treated females. Therefore, this study did not demonstrate any clear carcinogenic effect of OPP-Na on mice at dietary levels of up to 2%.

Animals↗
PubMed1984

Promotion by ascorbic acid, sodium erythorbate and ethoxyquin of neoplastic lesions in rats initiated with N-butyl-N-(4-hydroxybutyl) nitrosamine.

The promoting effects of ascorbic acid, sodium erythorbate and ethoxyquin on two-stage urinary bladder carcinogenesis in F344 rats initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) at a dose of 0.05% in the drinking water were examined. Administration of 5% sodium erythorbate in the diet significantly increased the incidences of preneoplastic lesions, papilloma and cancer of the urinary bladder, whereas administration of 5% ascorbic acid in the diet did not. Administration of 0.8% ethoxyquin also increased the incidence of neoplastic lesions. Administrations of 5% sodium L-ascorbate and 5% sodium erythorbate caused increases in the pH, the sodium content and crystals of MgNH4PO4 in the urine. These results show that sodium erythorbate and ethoxyquin promote urinary bladder carcinogenesis, while ascorbic acid does not.

Animals↗
PubMed1984

Changes in body temperature and thermosensitivity of preoptic and septal neurons during hippocampal stimulation.

The effects of electrical stimulation of the ventral subiculum (VSB) of hippocampal formation on the thermosensitivity of neurons in the preoptic area and the septum (PO/SP) were studied in the urethane-anesthetized rat. The local thermosensitivity of sixteen of 28 PO/SP thermosensitive neurons (25 warm-units and 3 cold-units) was reduced or lost during low frequency (4.8 Hz) stimulation of VSB. The extent of reduction was positively correlated to the magnitude of inhibition by the VSB stimulation. Thermosensitivity did not change in 11 of the remaining 12 warm-units and increased slightly in one warm-unit during VSB stimulation. In the conscious rat, bilateral stimulation (5 Hz) of VSB for 10 min caused a rise in rectal temperature of 0.28-0.87 degrees C in a warm environment (30-33 degrees C) and a fall of 0.18-0.57 degrees C in a cold (9.4-9.8 degrees C) environment. The results suggest that the predominantly inhibitory input from VSB decreases the thermosensitivity of PO/SP warm- and cold-sensitive neurons and thereby reduces the ability of thermoregulation.

Animals↗