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Biomedical subjects

M Konno

Publications and source records attributed to M Konno.

At least 109 records · Page 6Linked to original sources
PubMed1985

Occurrence of a beta-lactam-inducible penicillin-binding protein in methicillin-resistant staphylococci.

The mechanism of methicillin resistance was investigated in methicillin-resistant staphylococci (MRS) and in variants which had lost methicillin resistance. Phase-contrast microscopy showed that cells swelled at low concentrations of beta-lactam antibiotics in both MRS and variants which had lost methicillin resistance. Cells of variants which had lost methicillin resistance were lysed easily when higher concentrations of antibiotic were used. In contrast, MRS cells remained swollen at even higher concentrations of antibiotics. Furthermore, bacterial growth was inhibited at antibiotic concentrations much lower than MICs for MRS. Examination of the penicillin-binding proteins (PBPs) in MRS revealed that a new PBP-2' (molecular weight, 74,000) was induced in large quantity by exposure to beta-lactams. PBP-2' was produced constitutively in variants of MRS which had lost a penicillinase plasmid. The induction of PBP-2' by beta-lactams was not detected in variants which had lost methicillin resistance. High concentrations of beta-lactam were required for saturation of PBP-2'. The optimum antibiotic concentration for the induction of PBP-2' varied with the beta-lactam used as the inducer, and PBP-2' was produced in a larger amount at 32 degrees C than at 37 degrees C. From these results, we suggest that the mechanism of methicillin resistance depends on the induction of PBP-2', which may function as a detour enzyme for PBP-2 or PBP-3 or may be a particular enzyme involved in peptidoglycan synthesis.

Anti-Bacterial Agents↗
PubMed1984

Purification and characterization of aminoglycoside-modifying enzymes from Staphylococcus aureus and Staphylococcus epidermidis.

Several strains of Staphylococcus aureus and Staphylococcus epidermidis, exhibiting characteristic resistance patterns to aminoglycoside antibiotics, were examined. The aminoglycoside-modifying enzymes from these strains were purified by DEAE-Sephadex A-50 chromatography, affinity chromatography, and Sephadex G-100 gel filtration. Three enzymes, a 3'-phosphotransferase III (molecular weight, 31,000; pI 4.1), a bifunctional enzyme having 6'-acetyltransferase and 2"-phosphotransferase (molecular weight, 56,000; pI 4.1) activity, and a 4'4"-adenylytransferase (molecular weight, 34,000; pI 4.7), were isolated from crude extracts of the resistant strains. Aminoglycoside-modifying enzymes with identical enzymatic properties derived from S. aureus and S. epidermidis were also immunologically identical.

Acetyltransferases↗
PubMed1983

Synthesis and 5-lipoxygenase inhibitory activities of eicosanoid compounds.

Ten eicosanoid compounds (3, 6, 9, 11, 12, 15, 18, 21, 23, and 25), methyl (6E,8Z,11Z,14Z)-5-hydroxy-6,8,11,14-eicosatetraenoate (5-HETE, 10), leukotriene A4 (26), and (5S,6E,8E,10E,12RS,14E)-5,12-dihydroxy-6,8,10,14-eicosatetraenoic acid (5,12-diHETE, 27) were prepared and their inhibitory activities against the 5-lipoxygenase from guinea pig polymorphonuclear leukocytes (PMNL) were tested. 5,6-Methanoleukotriene A4 (18) was especially a potent and specific inhibitor of the 5-lipoxygenase without inhibiting the cyclooxygenase and the 12-lipoxygenase. Leukotriene A4, 5-HETE, and 5,12-diHETE also have inhibitory activities against the 5-lipoxygenase at micromolar concentrations, which can regulate the formation of slow-reacting substance of anaphylaxis intracellulary.

Animals↗
PubMed1983

[Oyster-associated hepatitis A].

We have experienced ten cases of hepatitis, type A, from March to April in 1983. All patients have taken raw oyster before hepatitis developed. The symptoms such as fever and/or diarrhea developed within 4 weeks after the patients have taken oyster. No cases of hepatitis in children were found out. From these results, it was concluded that the causes of hepatitis, type A, which we have experienced, are associated with raw oyster. HAV was not detected in shellfish by the method of radioimmunoassay.

Adult↗
PubMed1983

[Experiences with blood component transfusion and plasmapheresis during the last 6 months].

Our experiences with blood component transfusion and plasma exchange therapy during the last 6 months were reported. Total amounts used were 1,100 units with thrombocytes and 15 times (1 X 10(10) cells each time) with granulocytes obtained by centrifugation. Plasmapheresis was done 11 times with 7 patients and results obtained were compared with those of filtration leucapheresis which was done 100 times. Advantages and disadvantages of these methods are discussed.

Adolescent↗