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M Katoh

Publications and source records attributed to M Katoh.

At least 217 records · Page 12Linked to original sources
PubMed1995

A mechanism of resistance to partial macrolide and streptogramin B antibiotics in Staphylococcus aureus clinically isolated in Hungary.

A plasmid pEP2104 originated from Staphylococcus aureus was clinically isolated in Hungary during 1977. The plasmid mediates inducible resistance to PMS-antibiotics; partial macrolide [the 14-membered macrolides, erythromycin (EM) and oleandomycin and the 16-membered macrolides mycinamicin I (MCM I) and mycinamicin II (MCM II)and type B streptogramin (MKM-B) antibiotics. The sequence of 31 amino acid residues obtained by N-terminal analysis of the 63kDa protein (MsrSA) present in the membrane from 8325(pEP2104) cells whose PMS-resistance was induced by a concentration of 1.35 micrograms EM/ml [EM-induced 8325(pEP2104)], was identical to the corresponding sequence in a membrane protein MsrA related to promoting efflux of [14C]EM [Ross J.I., et al., Mol. Microbiol., 4, 1207 (1990)]. A constitutive PMS-resistant strain 8325(pMC38) was obtained from the 8325( pEP2104) strain in the presence of 1 microgram MCMI/ml. No inactivation of EM in EM-induced 8325(pEP2104) was observed. Moreover, poly (A)-directed polylysine synthesis by a cell-free system containing ribosomes from EM-induced 8325 (pEP2104) cells and S100 from Escherichia coli was inhibited by not only EM but spiramycin and MKM-B [Matsuoka M., et al., Biol. Pharm. Bull., 16, 1288 (1993)]. In addition, ribosomes from both EM-induced 8325 (pEP2104) and 8325(pMC38) strains showed about the same affinity as those from the host stain. NCTC8325. These results suggest, that like MsrA protein, active drug-efflux due to MsrSA protein may be responsible for PMS-resistance. How can the 8325 (pMC38) strain discriminate PMS-antibiotics from most of 16-membered macrolides and lincosamides? A possible explanation is discussed in terms of the pKa-value related to the physicochemical nature of the antibiotics.

Amino Acid Sequence↗
PubMed1995

[Ameliorating effect of lactitol on experimental hepatic encephalopathy in Eck fistula dogs].

Eck fistula (portacaval shunted) dogs were prepared for use as an experimental model of chronic hepatic encephalopathy. The effect of lactitol on hepatic encephalopathy was investigated by observing the behavior, electroencephalograms (EEGs) and visually evoked potentials (VEPs) of the experimental dogs. Lactitol was administered intragastrically once a day for 12 weeks from the third week after the portacaval-shunt operation and the behavior, EEGs and VEPs of the dogs were observed every two weeks. Dogs not given lactitol became sluggish, then apparently blind, and eventually fell into a coma, over a period of several weeks after the operation. Some dogs died. The EEGs revealed low-voltage slow waves and, at a later stage, displayed flattening in some dogs. The VEPs displayed prolonged latency of both the positive and the negative component as well as an increased amplitude. Lactitol at 1 or 3 g/kg/day suppressed the behavioral symptoms and the changes in the EEGs and the VEPs. These results suggest that lactitol may be useful for the treatment of various nervous symptoms in patients with hepatic encephalopathy accompanied by hyperammonemia.

Animals↗
PubMed1995

[Rupture of dissecting aortic aneurysm associated with the right-sided aortic arch and anomalous course of the left brachiocephalic vein--a case report].

A case of ruptured dissecting aortic aneurysm (DeBakey IIIb) associated with the right sided aortic arch and anomalous course of the left branchiocephalic vein was reported. A sixty-nine-year-old female suddenly had the severe back pain and soon fell into shock. The diagnosis of a ruptured dissecting aortic aneurysm associated with the right sided aortic was obtained on CT scanning. CT films also showed the left brachiocephalic vein behind the ascending aorta. Emergency operation was performed through median sternotomy and left thoracotomy. The descending aorta, forming an aneurysm with the aberrant subclavian artery, prominently protruded far to the left, and was located behind the trachea and the esophagus. Extra-anatomical bypass grafting was performed between the ascending aorta and the distal descending aorta. The patient eventually died of multiple organ failure on the 11th day after operation. These findings were confirmed by autopsy. A rare vascular anomaly with aortic dissection was reported, and a surgical approach to that lesion was discussed.

Aged↗
PubMed1995

[Continuous epidural droperidol for postoperative pain].

We investigated the proper dosage of droperidol continuously infused into the epidural space. Sixty patients who received continuous epidural infusion of buprenorphine for 24 hours were divided into four groups (Group I: only buprenorphine, Group II: 1.25 mg of droperidol added to buprenorphine, Group III: 2.5 mg of droperidol added to buprenorphine, Group IV: 5 mg of droperidol added to buprenorphine). No significant difference was observed in prevention of nausea and vomiting among 4 groups. But in group II, III and IV, there was a tendency of increased analgesic effects of buprenorphine. Especially in group III, the pain level was significantly lower and number of doses of bupivacaine was significantly fewer than in group I. In conclusion, droperidol 2.5 mg continuously infused into epidural space increases analgesic effects of buprenorphine.

Analgesia, Epidural↗
PubMed1995

[Promiscuous T cell hybridoma derived from NOD mouse].

In previous studies of this laboratory, epitope (site contacts with TCR) and agretope (site contacts with MHC molecule) were determined on p43-58 peptide composed of residues 43 to 58 of pigeon cytochrome c. Position 50 was shown to be a major epitopic site. Positions 46 and 54 were agretopic sites and we could determine specific amino acids on the agretopic positions which bound to each relevant I-A or I-E molecule. Using NOD mice, amino acids on the agretopic positions bound to I-Ag7 molecules were analyzed. Arginine (R) at position 46 and alanine (A) at position 54 were shown to be an agretopic motif bound to I-Ag7 molecules. I then established hybridomas specific for a p43-58 analogue, 46R50E54A, which contains R, glutamic acid (E) and A at positions 46, 50 and 54, respectively. Among the 46R50E54A-specific T cell hybridomas, a highly promiscuous hybridoma, NOE33-1-2, which recognized 46R50E54A with a variety of I-A molecules (I-Ad,s,u,v) as well as with I-Ag7 was obtained. Interestingly, NOE33-1-2 cells exhibited almost same responding pattern to various 46R50E54A analogue peptides as bulk lymph node T cells from each I-A bearing mice immunized with a 46R50E54A analogue did. Thus, the responding pattern of NOE33-1-2 appeared to be simply reflected by the binding affinity of the 46R50E54A analogues to the relevant I-A molecule. However, subsequent analysis with I-Ad and mutant I-Ad expressing antigen presenting cells (APC) showed that the floor part of beta chain of the I-Ad molecule was profoundly involved in interaction among TCR of NOE33-1-2, 46R50E54A and the I-Ad molecule. On the other hand, this part appeared not to be important in responses of all other 46R50E54A-specific and I-Ad restricted T cell hybridomas derived from I-Ad or I-Ab mice. No difference was shown in the expression of accessory molecules which might interpret the queer interaction between TCR of NOE33-1-2, antigenic peptide and MHC molecule. When NOE33-1-2 cells were competed with T cell hybridomas derived from I-Ad mice for I-Ad plus peptide Ag, the TCR of NOE33-1-2 cells showed higher affinity to the stimulatory complexes than that of latter hybridoma cells. These findings suggest that NOE33-1-2 hybridoma cells are of peculiar characteristics which may be attributable to negative or positive selection under influence of I-Ag7 molecules.

Amino Acid Sequence↗
PubMed1995

[Clinical analysis of 62 patients with blunt renal trauma].

Sixty two patients with blunt renal trauma were treated and followed in our clinic between 1976 and 1993. Immediate operation was performed in one with major laceration, 3 with ruptures and one with pedicle injury, that is, nephrectomy in 4 and partial nephrectomy in one. Expectant management with the purpose of preserving the injured kidney was performed in 33 contusions, 20 minor lacerations and 5 major lacerations, resulting in no complications. We confirm that expectant management of blunt renal trauma may be reliable if the condition of the patient is stable even in the case of rupture, and the treatment of associated injury is preferential.

Accidents, Traffic↗
PubMed1995

[Chymotrypsin].

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Chymotrypsin↗
PubMed1995

A new method for the assay of exposed platelet fibrinogen receptor using a chemiluminescent label.

Assay of the platelet fibrinogen-binding receptor glycoprotein (GP) IIb/IIIa is widely performed using 125I-labeled fibrinogen (125I-fibrinogen). We successfully devised a receptor binding assay system with high selectivity and sensitivity using a stable chemiluminescent acridinium derivative-I-labeled fibrinogen (acridinium-fibrinogen). Human fibrinogen is saline was labeled with equimolar acridinium dissolved in dimethylformamide, and allowed to react with gel-filtered human platelets in the presence of ADP. Acridinium-fibrinogen binding to GPIIb/IIIa was assayed by measuring chemiluminescence emitted on addition of 0.1 N NaOH containing 0.06% H2O2 in a luminometer. Non-specific binding was measured in the presence of 10 mM EDTA. Acridinium-fibrinogen binding to human platelets was rapid and reversible, specific and saturable, and dependent on ADP concentrations. Scatchard plot analysis revealed one class of binding sites with Kd of 326 nM and Bmax of 7.8 pmol/10(8) platelets. These values were comparable to the data obtained by using 125I-fibrinogen. Unlabeled fibrinogen, RGDS, and HHLGGAKQAGDV (fibrinogen gamma-chain 400-411) displaced acridinium-fibrinogen from its binding site with Ki values of 322 nM, 9.2 microM and 31.3 microM, respectively. Thus, this binding assay system may be useful in measuring the binding between platelet GPIIb/IIIa and fibrinogen without using a radioisotope.

Acridines↗
PubMed1994

RNA/DNA hybrid duplexes with identical nearest-neighbor base-pairs have identical stability.

Energetic behaviors of eight pairs of RNA/DNA hybrid duplexes with identical nearest neighbors have been investigated by UV melting analysis. In the pairs with identical nearest-neighbor pairs, the melting curve traces at the same strand concentration were very similar. The average difference in stabilization energy of these pairs was 4%, which was about expected within experimental error. These results indicate that the nearest-neighbor model is valid for predicting the stability of RNA/DNA hybrid duplexes as well as RNA/RNA and DNA/DNA duplexes.

Base Composition↗
PubMed1994

Inhibitory effect of clentiazem (TA-3090) on platelet aggregation--alone and in combination with aspirin or ticlopidine.

Clentiazem (a novel calcium antagonist) and its basic metabolites (MB1-MB7) showed inhibitory effects on collagen-induced platelet aggregation in human platelets. All the basic metabolites (IC50:8-22 micrograms/ml) had much stronger inhibitory effects than clentiazem itself (IC50:53 micrograms/ml), but the acidic metabolites (MA1-MA4) had no inhibitory effects even at 300 micrograms/ml. Other calcium antagonists (diltiazem, verapamil, nicardipine and nimodipine) also showed similar inhibitory effects although nicardipine and nimodipine were less active than the other drugs. The inhibitory effect of clentiazem was enhanced in the presence of aspirin or ticlopidine. Diltiazem and nicardipine also exhibited a similar potentiation of the anti-platelet effect in combination with aspirin or ticlopidine. Clentiazem also inhibited collagen-induced thromboxane B2 production by the platelets, and this inhibition by clentiazem was additively enhanced by the presence of aspirin. When both clentiazem and aspirin were orally administered to rats, platelet aggregation was additively inhibited. These results indicate that a combination therapy with clentiazem plus aspirin or clentiazem plus ticlopidine may be useful for the prevention and/or treatment of thrombotic disorders.

Animals↗
PubMed1994

NE-100, a novel sigma receptor ligand: effect on phencyclidine-induced behaviors in rats, dogs and monkeys.

Phencyclidine (PCP)-induced psychosis is a useful animal model for studies on schizophrenia. N, N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)-phenyl]- ethylamine monohydrochloride (NE-100) had no effect on conditioned avoidance responses (CAR) in rats, whereas, the PCP-induced impairment of avoidance inhibition was attenuated by NE-100. The PCP-induced ataxia or decreased attention in rhesus monkeys was to some extent overcome by NE-100. In dogs, PCP-induced either head-weaving behavior or ataxia, effects which were blocked by NE-100. Administration of PCP led to an increase in beta-2 and a decrease in delta relative power (RP) activity in cortical background spectral electroencephalographics (ECoG) in dogs. While NE-100 in itself showed no significant change in beta-2 and delta RP, NE-100 did block the PCP-induced beta-2 increase and delta decrease. These findings indicate that NE-100 attenuates the effect of PCP in experimental animals. This drug is being considered as a therapeutic for the treatment of patients in the schizophrenia.

Animals↗
PubMed1994

Studies on mutations in male germ cells of transgenic mice following exposure to isopropyl methanesulfonate, ethylnitrosourea or X-ray.

Transgenic mice have recently been used for mutagenesis assays in vivo. The present study was undertaken to clarify whether such assays can detect mutations induced after treatment of male germ cells in mouse with isopropyl methanesulfonate (iPMS), ethylnitrosourea (ENU) or X-ray irradiation. The transgenic mice used for assay are Muta Mouse (MM) strain, which carries 80 copies of the bacterial lacZ gene per cell as targets for mutagenesis. Male MM animals were given a single intraperitoneal injection of 200 mg/kg iPMS, 150 mg/kg ENU or were irradiated with 500 rads of X-rays. Vasa deferential sperm, caudal epididymal sperm and/or whole testes were extracted at various times after treatment with each agent. After the genomic DNA was extracted from each tissue, mutation analysis at the lacZ locus was carried out by the method of Myhr et al. The spontaneous lacZ- mutant frequencies were on the order of 10(-5)-10(-6). The lacZ- mutant frequencies in all treatment groups were increased over the control animals. The iPMS-induced mutant frequency in postmeiotic stages was low. However, ENU induced relatively high mutant frequencies in the spermatogonia. X-rays induced mutant frequencies in the late spermatid and early spermatid stages that were higher than the mutant frequencies in spermatogonia. Mutant frequencies in MM detected after treatment of male germ cells with ENU or X-rays were lower than mutant frequencies detected by the mouse specific-locus test in previous reports. Hence, considering the lower resolution power of the transgenic animal mutagenesis assays using the target lacZ gene compared with the specific locus test, to detect mutations induced in male germ cells, it is not clear whether this assay is a practical alternative to the specific locus test.

Animals↗
PubMed1994

Expression of MRP14, 27E10, interferon-alpha and leukocyte common antigen by reactive microglia in postmortem human brain tissue.

We have immunohistochemically investigated the localization of a panel of leukocyte-related molecules in postmortem human brain tissue from control subjects and patients with Alzheimer's disease (AD). Microglia constitutively express leukocyte common antigens (LCA) with CD45RB determinants. Depending on the state of activation, microglia become positive for the myeloid cell-specific calcium binding protein MRP14, LCA with CD45RO determinant, interferon-alpha, and an antigen recognized by monoclonal antibody 27E10. In AD lesions, these cells are activated in a manner consistent with a chronic inflammatory state. The results of this study have shown further parallels in protein expression between activated microglia and activated leukocytes of the myeloid lineage.

Aged↗
PubMed1994

Functional studies on MEL-14+ and MEL-14- T cells in peripheral lymphoid tissues.

Functions of MEL-14+ T cells and MEL-14- T cells in peripheral lymphoid tissues were analyzed and compared. The MEL-14- T cells, representing a minor subpopulation of spleen and lymph node T cells, generated considerably higher mixed lymphocyte reaction and mitogen responses than the MEL-14+ T cells in any lymphoid tissues studied. Furthermore, upon stimulation with ConA the MEL-14- CD8+ T cells produced significantly larger amounts of IL-2 and IFN-gamma than MEL-14+ CD8+ T cells did. A similar but less marked observation was obtained with the CD4+ T cell population. Furthermore, when B10.BR mice were immunized with AKR (Mls-1a) spleen cells, the proportion of the Mls-1a reactive V beta 6+ T cells from draining lymph nodes increased and a substantial proportion of the increasing V beta 6+ T cells was shown to be MEL-14-. The present findings on the whole indicate that MEL-14- T cells in the peripheral lymphoid tissues are at functionally high levels and may represent memory cells which have been previously stimulated in vivo.

Animals↗
PubMed1994

Abnormal p53 expression in human lung cancer is associated with histologic subtypes and patient smoking history.

Among the most common mutations in human lung cancer are those affecting the p53 gene. The expression of p53 in the nucleus is considered an immunohistochemical reflection of the nuclear accumulation of mutant p53 protein, which is coded by the p53 gene with missense mutation and has a prolonged half-life. In the present study, p53 expression detected by means of immunohistochemistry occurred frequently in human lung cancer and was associated with histologic subtypes. The alteration in the p53 gene was found to be a relatively early genetic event in the development and progression of lung cancer and to be maintained in the process of metastasis: abnormal p53 expression was found in both the early and late clinical stages, and identical p53 expression was detected consistently among primary and metastatic lesions from the same patients. Furthermore, an observed association between abnormal p53 expression and the patients' smoking history suggests that the p53 gene could be a common target of tobacco-associated carcinogenesis in lung cancer.

Carcinoma, Non-Small-Cell Lung↗
PubMed1994

Epitopes and biological activities of two monoclonal antibodies to platelet integrin alpha IIb beta 3.

We have developed two monoclonal antibodies (MAbs), B6A3 and C4G1. The whole molecules of the two MAbs inhibited in vitro human platelet aggregation induced by either ADP, collagen or thrombin, and their F(ab')2 fragments inhibited ex vivo platelet aggregation induced by ADP in monkey. The concentrations necessary for complete inhibition were 5 and 1 microgram/ml for B6A3 and C4G1, respectively. The Fab fragment of C4G1 but not B6A3 inhibited platelet aggregation. B6A3 and C4G1 bound to activated platelets with dissociation constants of 0.25 and 0.82 nM, respectively. B6A3 recognized an epitope on beta 3, which was sensitive to reduction and alkylation of cystine residues, and C4G1 recognized a conformational epitope on the alpha IIb beta 3 complex, which was sensitive to EDTA. The binding of fibrinogen to activated platelets was inhibited by both MAbs. However, the binding of fibrinogen to isolated alpha IIb beta 3 was inhibited by the whole molecule of C4G1 but not B6A3, although both MAbs bound to the isolated alpha IIb beta 3. The binding of these MAbs to the isolated alpha IIb beta 3 was not inhibited by either Arg Gly Asp Ser (RGDS) or fibrinogen gamma-peptide. In addition, B6A3 but not C4G1 bound to human endothelial cells. These MAbs should contribute to the elucidation of the mechanism of platelet aggregation.

Amino Acid Sequence↗
PubMed1994

Brain perfusion SPECT in a patient with a subtle venous angioma.

Brain SPECT of regional cerebral blood flow using I-123 IMP demonstrated a focally decreased perfusion area immediately adjacent to a venous angioma in a patient with simple partial seizures. A positive correlation was obtained among the location of the venous angioma, the decreased perfusion area on SPECT images, and the electroencephalographic focus. Anomalous venous drainage through a venous angioma may explain a perfusion disturbance in the surrounding brain of the angioma. High-resolution SPECT imaging with magnetic resonance guidance provides useful information on the pathophysiology of venous angiomas.

Adult↗