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Biomedical subjects

Y Asahi

Publications and source records attributed to Y Asahi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Combinational detection of autolysin and penicillin-binding protein 2B genes of Streptococcus pneumoniae by PCR.

PCR was used to identify penicillin resistance in 1,062 clinical isolates of Streptococcus pneumoniae. Three sets of primers were designed to amplify (i) a 240-bp fragment of the penicillin-binding protein (PBP) 2B gene (pbp2b) of penicillin-susceptible S. pneumoniae (PSSP), (ii) a 215-bp fragment of the class A mutations of the pbp2b gene present in penicillin-resistant S. pneumoniae, and (iii) a 286-bp fragment of the class B mutation. In addition, a set of primers that amplify 273 bp of the autolysin (lytA) gene was applied in combination with the above to identify S. pneumoniae. Of 621 isolates for which MICs of penicillin were < or = 0.06 mu g/ml, 614 (98.9%) were ascertained as having DNA fragments amplified by the PSSP primers. Of 441 isolates for which MICs of penicillin were > or = 0.125 mu g/ml, a class A mutation was detected in only 8 (1.8%), a class B mutation was detected in 310 (70.3%), and neither class A nor class B mutations were found in the remaining 123 (27.9%). However, when analysis was limited to isolates for which MICs of penicillin were > or = 1.0 mu g/ml, 247 isolates (89.8%) of 275 were found to possess a class B mutation. When PBPs were analyzed in 12 isolates with unclear mutations of the pbp2b gene by using [3H]benzylpenicillin, low affinity to PBP 2B was observed in them all. These findings suggest that a pbp2b mutation other than class A or class B is present in these isolates. These results also indicate that it may be possible to identify PSSP and penicillin-resistant S. pneumoniae by applying PCR using a combination of primers to detect the susceptible pbp2b gene, resistant pbp2b gene mutations, and the lytA gene.

Aminoacyltransferases↗
PubMed1995

A unique chromosome translocation, t(11;12;18)(q21;q13;q21) [correction of t(11;12;18)(q13;q13;q12)], in primary lung lymphoma.

A 54-year old man with a primary lung lymphoma of mucosa-associated lymphoid tissue (MALT) origin whose tumor cells had a t(11;12;18)(q13;q13;q12) chromosome abnormality is described. The morphologic, immunologic, and molecular biologic investigations showed that the patient's lung tumor consisted of small lymphoid cells that expressed monoclonal IgM, kappa-type immunoglobulin, and immunoglobulin gene (JH and C kappa) rearrangements. Cytogenetic study revealed that the tumor cells contained a unique chromosome translocation, t(11;12;18)(q13;q13;q12), that has not been reported previously in lymphoma.

Chromosome Aberrations↗
PubMed1995

Insulin resistance in skeletal muscle of the male Otsuka Long-Evans Tokushima Fatty rat, a new model of NIDDM.

The Otsuka Long-Evans Tokushima Fatty rat is a new inbred obese strain with a late onset and chronic course of spontaneous hyperglycaemia in the male, and is considered to be a model of non-insulin-dependent diabetes mellitus [1, 2]. Fat distribution analysis showed a typical accumulation of intra-abdominal visceral fat in Otsuka Long-Evans Tokushima Fatty rats compared with a control strain, Long-Evans Tokushima Otsuka rats. To examine the insulin sensitivity of Otsuka Long-Evans Tokushima Fatty rats, we performed euglycaemic hyperinsulinaemic clamp experiments in vivo in rats under anaesthesia on this strain and on Long-Evans Tokushima Otsuka rats. The Otsuka Long-Evans Tokushima Fatty rats showed lower values for the glucose infusion rate (60% of the control at 12 weeks old and 20-30% of the control at 18, 24, 30 and 39 weeks old) than age-matched controls, indicating the development of insulin resistance with age. Hindlimb perfusion experiments in vitro also showed a 45% decrease of insulin-stimulated glucose uptake in Otsuka Long-Evens Tokushima Fatty rats in the diabetic stage. These results indicate that insulin resistance exists in the skeletal muscle of Otsuka Long-Evans Tokushima Fatty rats. To obtain information on the mechanism of insulin resistance in the skeletal muscle of Otsuka Long-Evans Tokushima Fatty rats, the insulin binding, autophosphorylation and tyrosine kinase activity of their partially-purified insulin receptors in vitro were compared with those from control rats. The results showed no marked differences in these insulin receptor functions between diabetic and control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1995

Direct transplantation of chronic myelogenous leukemia cells into nude mice and establishment of a leukemic stem cell (Ph1+, CD34+) line dependent on mouse bone marrow stromal cells in vitro.

Peripheral blood cells from a female patient with Ph1-positive chronic myelogenous leukemia (CML) in blast crisis were serially transplanted in BALB/c nude mice for 16 passages. This in vivo cell line, designated CML-N-1, had Ph1 chromosome abnormality and BCR gene rearrangement. The cells expressed CD11b, CD13, CD33, CD34, CD38, and HLA-DR antigens until the 11th passage and subcutaneous tumors produced by these passages were composed of admixtures of immature and maturing cells that differentiated to basophils when cultured in vitro. From the 12th passage on, the tumors became composed mainly of immature cells expressing CD13, CD34, and HLA-DR, and no longer differentiated to basophils even upon in vitro culture. In contrast to the vigorous proliferation in vivo, CML-N-1 cells from any passage failed to proliferate in vitro under standard liquid culture conditions with or without growth factors, such as granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, monocyte colony-stimulating factor, interleukin 3, interleukin 6 and stem cell factor. However, a continuously growing cell line, designated CML-C-1, was established by culturing CML-N-1 cells on feeder layers of mouse bone marrow stromal cells. This mouse bone marrow stromal cell-dependent cell line showed immature cell morphology and expressed early myeloid phenotype positive for CD13, CD34, and HLA-DR. These results indicate that mouse bone marrow stromal cells provide a certain growth factor(s) active on human leukemia cells.

Adult↗
PubMed1995

In vitro and in vivo antibacterial activities of BO-2727, a new carbapenem.

BO-2727, a new injectable carbapenem, was evaluated for its in vitro and in vivo antibacterial activities in comparison with those of biapenem, meropenem, imipenem, cefpirome, and ceftazidime. BO-2727 had activity comparable to that of imipenem against methicillin-susceptible staphylococci and streptococci, with MICs at which 90% of strains tested (MIC90s) are inhibited being equal to 0.5 microgram/ml or less. Against methicillin-resistant staphylococci, BO-2727 was the most active among the antibiotics tested, with MIC90s ranging from 4 to 8 micrograms/ml. BO-2727 was highly active against members of the family Enterobacteriaceae, Haemophilus influenzae, and Moraxella catarrhalis, with MIC90s ranging from 0.006 to 2 micrograms/ml. BO-2727 was also highly active against Pseudomonas aeruginosa (imipenem-susceptible strains), for which the MIC90 was 2 micrograms/ml, which was lower than those of imipenem, cefpirome, and ceftazidime and comparable to those of biapenem and meropenem. Differences in activity between BO-2727 and the other carbapenems against imipenem-resistant P. aeruginosa were particularly striking (MIC90, 8 micrograms/ml). Furthermore, BO-2727 displayed a high degree of activity against many of the ceftazidime-, ciprofloxacin-, and/or gentamicin-resistant isolates of P. aeruginosa. The in vivo efficacy of BO-2727 against experimental septicemia caused by gram-positive and gram-negative bacteria, including methicillin-resistant Staphylococcus aureus and imipenem-resistant P. aeruginosa, reflected its potent in vitro activity and high levels in plasma.

Animals↗
PubMed1993

Synergic activity of imipenem/cilastatin combined with cefotiam against methicillin-resistant Staphylococcus aureus.

The synergic activity of imipenem/cilastatin combined with cefotiam was studied in a mouse bacteraemia model. Combinations of imipenem plus cefotiam in ratios from 1:5 to 1:160 were more effective than either imipenem alone or cefotiam alone (P < 0.05). Synergy was observed against both beta-lactamase producing and beta-lactamase non-producing MRSA. Staggered combinations of imipenem with cefotiam (each drug was administered at a different time) were studied in an in-vitro pharmacokinetic system to clarify relationships between killing kinetics and pharmacodynamics of the combinations. In the in-vitro system, cefotiam (1 g over 30 min) administered 2 h after imipenem administration (250 mg over 30 min) reduced viable cell counts to an undetectable level and maintained this for 4 h, while the simultaneous administration of imipenem and cefotiam maintained an undetectable cell count for only 2 h. Furthermore, imipenem administered after cefotiam showed no synergy. These results indicate that the timing of dosing of each antibiotic influences synergy, and administration of cefotiam 2 h after imipenem is more effective than the other regimens.

Animals↗
PubMed1991

In-vitro activity of imipenem combined with beta-lactam antibiotics for methicillin-resistant Staphylococcus aureus.

The in-vitro activity of imipenem combined with beta-lactam antibiotics was studied for 25 strains of methicillin and imipenem-resistant Staphylococcus aureus (MRSA) in comparison with that of fosfomycin combined with cefmetazole. Using the chequerboard agar dilution method, strong synergy was seen for all strains for imipenem with cefoperazone, cefotiam, cefpiramide or piperacillin. All fractional inhibitory concentration indices (FIC indices) of these combinations were less than or equal to 0.12. For the combination of imipenem with cefotiam the synergy was found to be bactericidal, but was not affected by the temperature of incubation, the concentration of sodium chloride in the medium or beta-lactamase production. However, for the combination of fosfomycin with cefmetazole only 44% of the strains with a mean FIC index of 0.55, showed synergy. The remaining 56% of strains showed either partial synergy (44%) or additive activity (12%). The combinations of imipenem with the beta-lactam antibiotics were more effective than that of fosfomycin with cefmetazole.

Anti-Bacterial Agents↗
PubMed1991

Binding position of azathioprine with bovine serum albumin determined by measuring nuclear magnetic resonance relaxation time.

The interaction between azathioprine (AZ) and bovine serum albumin (BSA) is mainly due to hydrophobic binding according to the dependence of the binding constant on the ionic strength obtained by equilibrium dialysis. The binding constant and partition coefficient of AZ were smaller than those of warfarin, phenylbutazone and ibuprofen. Little variation in the proton chemical shift of AZ was observed whether there was an absence or presence of BSA (7.25 x 10(-5) M). The spin-lattice relaxation time (T1) of AZ decreased in the presence of BSA to 6-22%. The spin-spin relaxation rate (1/T2) of AZ increased 16-24 times for the methyl group and the imidazole ring and 8-13 times for the purine ring in the presence of BSA. The ratio of the spin-spin relaxation rate of the free AZ to the bound AZ ((1/T2)b/(1/T2)f) of the methyl group and the imidazole ring was 2-3 times larger than that of the purine ring. The binding of AZ to BSA was concluded to be mainly at the methyl group on the imidazole ring of AZ.

Animals↗
PubMed1990

[A successfully treated case of infective endocarditis due to Candida tropicalis].

A 34-year-old man, a heavy drinker, was admitted with a high fever and hematuria two months previously. Surgery was performed for acute sever pancreatitis and postoperatively antibiotics were administered with intravenous hyperalimentation. After discharge he was readmitted and infective endocarditis was strongly suspected because of high fever, hematuria, Osler's nodes, Janeway's lesions, splinter hemorrhages and mitral regurgitation. Penicillin G in combination with Gentamycine therapy was started on the first hospital day. On the second hospital day, blood culture revealed Candida tropicalis so Miconazole therapy was commenced. On the forth hospital day, he underwent surgery for replacement of a mitral prosthesis with a prosthetic valve because he had embolus in the radial artery. Despite intensive antifungal therapy, he showed no improvement in clinical symptoms. Then we changed the antifungal drug from Miconazole to Amphotericin B and 5-fluorocytosine. On the 109th hospital day, his clinical symptoms improved. Antifungal therapy was halted and at present 10 months later, he is healthy.

Adult↗
PubMed1989

In vitro and in vivo antibacterial activities of BO-1341, a new antipseudomonal cephalosporin.

BO-1341, a new antipseudomonal semisynthetic cephalosporin, was evaluated for in vitro and in vivo antibacterial activities in comparison with ceftazidime, cefotaxime, and cefoperazone. The in vitro activity of BO-1341 was generally superior or comparable to the activities of the reference antibiotics against clinical isolates of the family Enterobacteriaceae. BO-1341 was highly active against Pseudomonas aeruginosa (MIC for 90% of the strains tested, 1.56 micrograms/ml), Pseudomonas maltophilia (MIC for 50% of the strains tested, 1.56 micrograms/ml), and Acinetobacter calcoaceticus (MIC for 90% of the strains tested, 3.13 micrograms/ml). Furthermore, BO-1341 was highly active against P. aeruginosa isolates resistant to the other antibiotics. Of 199 P. aeruginosa isolates tested, only 2 were resistant to BO-1341. These two strains were also resistant to ceftazidime, cefotaxime, and cefoperazone. Haemophilus influenzae, Branhamella catarrhalis, and nonenteric streptococci were also susceptible to BO-1341, but Staphylococcus aureus, Streptococcus faecalis, and Bacteroides fragilis were not susceptible to the compound. The protective efficacy against experimental infections in mice caused by nine strains of gram-negative bacteria, including P. aeruginosa, reflected the potent in vitro activity.

Animals↗
PubMed1989

Binding position of phenylbutazone with bovine serum albumin determined by measuring nuclear magnetic resonance relaxation time.

The binding of phenylbutazone (PB) to bovine serum albumin (BSA) was considered to be predominantly due to hydrophobic interaction based on the thermodynamic parameters obtained by an equilibrium dialysis method. Little variation of proton nuclear magnetic resonance (1H-NMR) chemical shift of PB was found with change in the concentration of PB (0.5-5 mM) or upon the addition of BSA (7.25 x 10(-5) M). The NMR spectrum of PB in 0.1 M phosphate buffer solution at pH 7 showed that PB existed as a mesomeric anion. The spin-lattice relaxation time (T1) of PB was almost concentration-independent, but decreased in the presence of BSA to 36-38% for the phenyl group and 48-100% for the butyl group. The spin-spin relaxation time (T2) of PB was also almost independent of concentration, but was remarkably decreased in the presence of BSA to ca. 2.5% for the phenyl group and ca. 6-9% for the butyl group. The ratios of the spin-spin relaxation rate (1/T2) of the free PB to that of the bound PB were ca. 5000-11000 for the butyl group and ca. 23000 for the phenyl group. The binding of PB to BSA was considered to involve primarily the phenyl group.

Animals↗
PubMed1989

Biochemical properties of beta-lactamase produced by Bacteroides distasonis.

Three of 29 clinical isolates of Bacteroides distasonis strains, GAI2095, GAI2361 and GAI6270 were found to produce high levels of beta-lactamase relative to the remaining 26 strains. The enzymes from these strains showed a broad substrate profile, hydrolyzing cephaloridine, cephalothin, cefazolin, oxyimino-cephalosporins such as cefuroxime, cefotaxime and cefmenoxime, and piperacillin at high rates. Examination of the substrate profiles indicated that the enzymes were mainly oxyimino-cephalosporinases. Inactivation of latamoxef over a long time by crude enzyme extracts of GAI2095 and GAI2361 was detected by a microbiological assay. The enzyme activities were inhibited by imipenem, cefoxitin, clavulanic acid and sulbactam but not by EDTA. The majority of beta-lactamase activity was found in the cell extract prepared by ultrasonic treatment, especially in the precipitate by ultracentrifugation including membrane fraction. When the cells of B. distasonis were subjected to osmotic shock, negligible levels of beta-lactamase activity were found in the supernatant fluid. The enzymes appeared to be tightly associated with the cell envelope since detergents were required to elute these activities.

Anti-Bacterial Agents↗