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Biomedical subjects

M Inoue

Publications and source records attributed to M Inoue.

At least 109 records · Page 6Linked to original sources
PubMed1994

Antimicrobial activity of arbekacin, a new aminoglycoside antibiotic, against methicillin-resistant Staphylococcus aureus.

Arbekacin has excellent antibacterial activity and is also effective against methicillin-resistant Staphylococcus aureus (MRSA) resistant to aminoglycosides such as gentamicin, tobramycin, and methicillin-susceptible Staphylococcus aureus (MSSA). By coagulase typing, four different coagulase types were identified from 358 strains out of 387 MRSA isolated during 1993 in Japan. Among isolates collected in the survey period, about 89% had type 2 coagulase, and only a few had type 3 (4.5%), 4 (2.5%) or 7 (3.6%) coagulase. The distribution of coagulase types in Japan is quite different from those outside Japan which had type 4 coagulase. More than 72% of strains with types 2, 7 and untyped coagulase had high resistance to methicillin. All of the isolates with types 2, 3, 4, and 7 coagulase were highly resistant to gentamicin and tobramycin. 89% of isolates with type 7 coagulase, 2.5% of those with type 2 coagulase and 6.3% of those with type 3 coagulase were found to be arbekacin-resistant. No arbekacin-resistant MRSA was detected among the isolates with type 4 coagulase. In the present study, the authors attempted to determine the strong antibiotic activity of arbekacin against MRSA and particularly gentamicin-resistant MRSA. Arbekacin is not modified by the aminoglycoside-modifying enzyme, ANT (4')-1. Although arbekacin is inactivated by the enzyme APH (2")/AAC (6') which can modify both gentamicin and tobramycin, the rate of modification of arbekacin by this enzyme is only 17% or less of that of gentamicin.

Aminoglycosides↗
PubMed1993

Epitopic structure of Tn glycophorin A for an anti-Tn antibody (MLS 128).

Glycophorin A was digested with glycoprotease (Pasteurella haemolytica) and the digest was fractionated by a combination of high-pressure column chromatographies to produce the glycopeptides GPA-1 to GPA-6. Sequence analysis of the glycopeptides revealed that two serine residues (Ser-14 and Ser-15) are not glycosylated, Thr-17 and Ser-19 being glycosylated instead, in disagreement with the accepted structure. The glycopeptides thus obtained were treated with sialidase and beta-galactosidase. The Tn antigenicity, as assayed by the binding to a monoclonal anti-Tn antibody (MLS 128), was found exclusively in the glycopeptides including three (cluster I) or four (cluster II) consecutive residues of GalNAc-Ser/Thr, whereas the glycopeptide (GPA-2) containing two nonconsecutive GalNAc-Ser/Thr residues had practically no Tn antigenicity. The immunoreactivities of GPA-1 and GPA-3, containing both clusters I and II, and GPA-4, containing cluster II, were 63% (calcd. 67%), 81% (calcd. 86%), and 50% (calcd. 50%), respectively, of the immunoreactivity of GPA-5 or GPA-6, containing cluster I (the average being taken as the basis), based on the reactivity per GalNAc residue. These results indicate that clusters I and II react with the antibody to the same extent. The structure consisting of three consecutive glycosylated Ser/Thr residues may be essential for Tn antigenicity in the light of previous results for ovine submaxillary mucin.

Amino Acid Sequence↗
PubMed1993

Effects of treatment with methyl methanesulfonate during meiotic and postmeiotic stages and maturation of spermatozoa in mice.

DNA damage and its related effects were quantitatively measured in germ cells at various meiotic and postmeiotic stages in male mice treated with methyl methanesulfonate (MMS). Unscheduled DNA synthesis (UDS) took place most efficiently in germ cell stages from middle to late spermatocytes at the time of MMS treatment, and essentially no UDS was detected in the stages from late spermatid to maturing spermatozoa, suggesting the absence of DNA repair in late spermatids and maturing spermatozoa. Late spermatids and immature spermatozoa were, on the other hand, most sensitive to MMS in producing DNA single-strand breaks (SSB) as well as chromosome aberrations in eggs fertilized by the treated males. The storage of the spermatozoa in the reproductive tract appeared to enhance the production of SSB. DNA damages induced by MMS should cause various genetic effects during the postmeiotic stages and maturation of spermatozoa through mechanisms not related to excision repair.

Animals↗
PubMed1993

Characterization of Yersinia pseudotuberculosis serogroups O9, O10 and O11; subdivision of O1 serogroup into O1a, O1b, and O1c subgroups.

In this study, three new antigens (O9, O10 and O11) of Yersinia pseudotuberculosis are described. The O1 antigen is further subdivided into O1a, O1b and O1c. The methods used to prepare specific antisera for O-antigen identification are also described. Furthermore, the H antigens of these new serogroups are determined and their biochemical characteristics analysed. The antigenic formulae of the known serogroups within the basic antigenic scheme introduced by the authors' laboratories are presented.

Antigenic Variation↗
PubMed1993

Protective effect of the protease inhibitor leupeptin against myocardial stunning.

To elucidate whether activation of intracellular protease causes the contractile dysfunction of post-ischemic reperfused heart (stunned myocardium), the effect of leupeptin, a cysteine-protease inhibitor, was evaluated in isolated guinea pig hearts. Left ventricular (LV) isovolumic pressure was measured in hearts reperfused after global ischemia (15 min, 37 degrees C). Recovery of developed pressure during reperfusion in hearts treated with 50 microM leupeptin was significantly greater than that in untreated hearts [94.3 +/- 3.2% of control, n = 11 (mean +/- SEM] vs. 78.1 +/- 3.1%, n = 14), and was almost identical to that in nonischemic control (93.5 +/- 1.6%, n = 11). Maximal Ca(2+)-activated pressure, the intact-heart correlate of maximal Ca(2+)-activated force, was also evaluated at the end of experiments during tetani elicited by rapid pacing after exposure to ryanodine. Maximal Ca(2+)-activated pressure in hearts treated with leupeptin (168 +/- 4.6 mm Hg) was significantly higher than in untreated stunned hearts (144.5 +/- 5.7 mm Hg), but significantly lower than in nonischemic control (198.4 +/- 5.5 mm Hg). These results indicate that leupeptin has a protective effect against myocardial stunning. In coupling with previous reports of transient increase in intracellular [Ca2+] during ischemia and/or reperfusion, activation of proteases by Ca2+ overload is suggested to play a significant role in myocardial stunning.

Animals↗
PubMed1993

Phosphorylation-dependent regulation of nonselective cation channels in guinea pig chromaffin cells.

In guinea pig chromaffin cells, acetylcholine induces a nonselective cation current by activating a muscarinic receptor, probably m4. We investigated activation and deactivation processes of this current. The calmodulin antagonists trifluoperazine and calmidazolium reversibly suppressed the muscarinic activation of the nonselective cation current in a dose-dependent manner; the former was about six times less potent than the latter. H-7, a kinase inhibitor, also reversibly inhibited the muscarinic current with a concentration eliciting 50% of maximal inhibition of 277 microM. Internal application of vanadate, a nonspecific phosphatase inhibitor, enhanced the muscarinic current and markedly slowed the time course of its deactivation, but the phosphatase 1 and 2A inhibitors okadaic acid and calyculin A had no effects. Lowering Mg2+ concentration in the patch solution mimicked the effects of vanadate on the muscarinic current. Internal dialysis with vanadate or low-Mg2+ solution gradually led to development of an inward current, and the related voltage dependence was similar to that seen with the muscarinic cation current. These results suggest that kinase and Mg(2+)-dependent phosphatase are responsible for activation and deactivation of nonselective cation channels. The channels seem to be under the influence of both enzymes, even in the absence of external signals.

Animals↗
PubMed1993

Role of vagal nerves and atrial natriuretic hormone in vasopressin release and a diuresis under hypertonic volume expansion.

To assess whether increases in circulating atrial natriuretic hormone (ANH) in response to the plasma volume expansion, besides the volume receptor-mediated mechanisms, attenuate the arginine vasopressin (AVP) response to increased plasma osmolality and whether changes in plasma AVP and ANH affect renal solute excretion under hypertonic plasma volume expansion, hypertonic saline (0.95 mol/l saline) alone, hypertonic saline with 6% dextran (6D-HS) and hypertonic saline with 9% dextran (9D-HS) were administered into anesthetized dogs. In the control study, 0.15 mol/l NaCl alone was administered. Plasma AVP and ANH and cardiovascular and renal functions were determined. Hypertonic saline and 9D-HS also were administered into the vagotomized and sham operated dogs, and the same parameters were determined. Mean blood pressure and heart rate never changed in all the groups, but central venous pressure and plasma volume increased markedly in 6D-HS and 9D-HS groups. In the control and hypertonic saline groups, central venous pressure increased slightly but plasma volume never changed. Plasma AVP increased in the order of hypertonic saline, 6D-HS and 9D-HS, but plasma ANH increased in reverse order. Vagotomy restored the AVP response to 9D-HS to 75% of its response to hypertonic saline, with a marked rise in plasma ANH. Urine sodium and potassium excretion and urine flow increased in hypertonic saline, 6D-HS and 9D-HS groups, but these increases were comparable among the groups. In the control group, these parameters never changed. These results suggest that the volume receptor-mediated vagal neural and ANH responses to the plasma volume expansion may have an effect on the suppression of the AVP response to osmotic stimuli, and increased plasma ANH release never potentiated the natriuresis under the hypertonic plasma volume expansion.

Animals↗
PubMed1993

[The role of G-CSF in host defense mechanisms of the elderly].

It has been generally agreed that the elderly had a greater susceptibility, morbidity, and mortality in regard to a variety of bacterial infections. To clarify the host defence mechanism in the elderly, we studied the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on neutrophil functions, the production of G-CSF by peripheral blood monocytes in response to lipopolysaccharide (LPS) and the serum levels of G-CSF in patients with bacterial pneumonia. There was no significant difference in the phagocytic activity of neutrophils between the elderly and control young adults. rhG-CSF enhanced phagocytosis by neutrophils, and a similar degree of enhancement was obtained in both group. Killing activity of neutrophils assessed by the new nitroblue tetrazolium reduction test in the elderly was significantly lower than that in young adults (p < 0.001), however, pretreatment with rhG-CSF resulted in an increase of killing activity in the elderly, raising their response to a level compatible to that of young adults pretreated with rhG-CSF. The amount of G-CSF in the culture supernatants from LPS-stimulated peripheral blood monocytes of the elderly was significantly lower than that of young adults (p < 0.05). The serum levels of G-CSF in the acute phase of bacterial pneumonia in the elderly were significantly lower than those of young adults (p < 0.01). These results indicated that impaired monocyte function may contribute, at least in part, to susceptibility to bacterial infection in the elderly.

Adult↗
PubMed1993

Comparison of neural network and k-NN classification methods in medical image and voice recognitions.

We make a comparison of classification ability between BPN (Back Propagation Neural Network) and k-NN (k-Nearest Neighbor) classification methods. Voice data and patellar subluxation images are used. The result was that the average recognition rate of BPN was 9.2 percent higher than that of the k-NN classification method. Although k-NN classification is simple in theory, classification time was fairly long. Therefore, it seems that real time recognition is difficult. On the other hand, the BPN method is long in learning time but is very short in recognition time. Especially if the number of dimensions of the samples is large, it can be said that BPN is better than k-NN in classification ability.

Algorithms↗
PubMed1993

[UV-microspectrophotometric and flow cytometric analysis of the same samples using DAPI/HP staining].

A simple one-step double staining with DAPI and hematoporphyrin (HP) was used for UV-microspectrophotometric (UV-MSPM) and flow cytometry (FCM) analysis of the same samples. The specimens analyzed included fresh biopsy and/or surgical materials, trimmed 50 microns-thick paraffin sections and smears (with the latter not available for FCM). We provided the special technology for preserving the cytoplasm as far as possible to permit measurement of cell size and N/C ratio. DAPI indicates DNA content under 365 nm and HP of total protein content under 670 nm UV-MSPM. The DAPI can measure the nuclear size and the latter the cell size. DAPI/HP staining yielded much more accurate measurements than staining with FITC and PI. The use of both MSPM and FCM with cell sorting on the same samples is very helpful in cytology and histopathology for evaluating and differentiating borderline lesions and grade of malignancy, as well as oncostatic effectivity. Our goal is to combine this technology with the automated cytologic screening system CYBEST, which was developed by Tanaka et al, based on a morphometric device.

Adenocarcinoma↗
PubMed1992

[MR imaging evaluation of plica synoviallis mediopatellaris of the knee joint].

To evaluate the diagnostic ability of MR imaging for plica synoviallis mediopatellaris (PSM), we retrospectively reviewed the MR imaging findings of patellofemoral space in 20 knee joints of 11 patients. In all 20 knee joints, arthroscopy and MR imaging were available. MR imaging was performed with a 1.5 Tesla Magnetom (Siemens) using a round surface coil. Pulse sequences were SE (TR 600 ms/TE 26 ms), SE (TR 200 ms/TE 26, 70 ms) and FLASH (TR 450 ms/TE 15 ms/FA 90 degrees). In six of the 20 knees with PSM proved by arthroscopy, a low intensity band was shown above the medial condyle of the femur on both T1- and T2-weighted MR images, and on FLASH images this band was shown as intermediate intensity. In the other 14 knees with no PSM observed by arthroscopy, the low intensity band was not shown on MR imaging. In all 20 knees, a similar low intensity band was shown about 1 cm cranial to the medial condyle of the femur. This should not be diagnosed as PSM. The low intensity band seen on T1- and T2-weighted MR images and its anatomical relation to the medial condyle are important in diagnosing PSM.

Adolescent↗
PubMed1992

Histogenetic analysis of ovarian germ cell tumors by DNA fingerprinting.

The histogenesis of ovarian germ cell tumors (11 mature teratomas, three malignant transformations of mature teratomas, two immature teratomas, and four dysgerminomas) was investigated genetically using minisatellite DNA probes 33.15 and 33.6 for person-specific restriction fragment length polymorphism (DNA fingerprint) analysis. The DNA fingerprints of six ovarian teratomas were identical with those of mononuclear cells from each host, while some polymorphic bands observed in the host mononuclear cells were lost in the DNA fingerprints of the other five cases. The cases of malignant transformation of mature teratoma and immature teratoma showed that some polymorphic bands of DNA fingerprints from the host mononuclear cells were absent in the tumor tissues. In four cases with dysgerminomas, the DNA fingerprints of tumors were completely identical with those of the respective host mononuclear cells. The present results suggest that mature cystic teratomas of the ovary arise from germ cells arrested at various stages of meiosis, while immature teratomas are derived from postmeiotic germ cells. Malignant transformation may occur exclusively in the mature teratomas arising from postmeiotic germ cells. Dysgerminomas develop from premeiotic oogonia (primordial germ cells). Thus, DNA fingerprints are a useful and sensitive tool for identifying the pathogenesis of germ cell tumours.

Adolescent↗
PubMed1992

Crystal structure of papain-succinyl-Gln-Val-Val-Ala-Ala-p-nitroanilide complex at 1.7-A resolution: noncovalent binding mode of a common sequence of endogenous thiol protease inhibitors.

Succinyl-Gln-Val-Val-Ala-Ala-p-nitroanilide corresponding to a common sequence of endogenous thiol protease inhibitors is a noncompetitive reversible inhibitor of papain. In order to elucidate the binding mode of the inhibitor at the atomic level, its complex with papain was crystallized at ca. pH 7.0 using the hanging drop method, and the crystal structure was analyzed at 1.7-A resolution. The crystal has space group P2(1)2(1)2(1), with a = 43.09, b = 102.32, c = 49.69 A, and Z = 4. A total of 47,215 observed reflections were collected on the imaging plates using the same single crystal, and 19,833 unique reflections with Fo > sigma (Fo) were used for structure determination and refinement. The papain structure was determined by use of the atomic coordinates of papain previously reported, and then refined by the X-PLOR program. The inhibitor molecule was located on a difference Fourier map and fitted into the electron density with the aid of computer graphics. The complex structure was finally refined to R = 19.6% including 118 solvent molecules. The X-ray analysis of the complex crystal shows that the inhibitor is located at the R-domain side, not in the center of the binding site created by the R- and L-domains of papain. Such a binding mode of the inhibitor explains well the biological behavior that the inhibitor exhibits against papain. Comparison with the structure of papain-stefin B complex indicates that the structure of the Gln-Val-Val-Ala-Gly sequence itself is not necessarily the essential requisite for inhibitory activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Role of tyrosyl phosphorylation in neutrophil priming by tumor necrosis factor-alpha and granulocyte colony stimulating factor.

The ability of human tumor necrosis factor-alpha (TNF-alpha) and human granulocyte colony stimulating factor (G-CSF) to induce phosphorylation of protein tyrosyl residues in human peripheral neutrophils (PMN) was investigated by Western blot analysis with antiphosphotyrosine antibody. Both TNF-alpha and G-CSF increased the tyrosyl phosphorylation of various proteins, such as species of 54-, 63-, 72-, 83-, 98-, 108-, and 115-kDa proteins. The ligand-stimulated tyrosyl phosphorylation of the 115-kDa protein was time- and concentration-dependent. When the 115-kDa protein was phosphorylated, it was recovered from membrane fractions. The phosphorylation of the 115-kDa protein was inhibited by genistein and alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamide (ST 638), inhibitors of tyrosine kinase (TK), and was enhanced by 1-(5-isoquinoline-sulfonyl) methyl-piperazine dihydrochloride (H-7) and staurosporine, inhibitors of Ca(2+)- and phospholipid-dependent protein kinase (PKC). Similar inhibition by the TK inhibitors and stimulation by the PKC inhibitors were also observed with formylmethionyl-leucyl-phenylalanine (FMLP)-induced superoxide (O2.-) generation by TNF-alpha- or G-CSF-primed PMN. Phosphorylation of the 115-kDa protein occurred in parallel with the ligand-dependent generation of O2.-. These and other observations suggested that substrate proteins for tyrosine kinase, such as the 115-kDa protein, might play critical roles in the mechanism for priming of neutrophils. This is the first report describing that tyrosyl phosphorylation is involved in the priming of neutrophils by G-CSF and TNF-alpha.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Crystal structure of papain-E64-c complex. Binding diversity of E64-c to papain S2 and S3 subsites.

In order to investigate the binding mode of E64-c (a synthetic cysteine proteinase inhibitor) to papain at the atomic level, the crystal structure of the complex was analysed by X-ray diffraction at 1.9 A (1 A is expressed in SI units as 0.1 nm) resolution. The crystal has a space group P2(1)2(1)2(1) with a = 43.37, b = 102.34 and c = 49.95 A. A total of 21,135 observed reflections were collected from the same crystal, and 14811 unique reflections of up to 1.9 A resolution [Fo > 3 sigma(Fo)] were used for the structure solution and refinement. The papain structure was determined by means of the molecular replacement method, and then the inhibitor was observed on a (2 magnitude of Fo-magnitude of Fc) difference Fourier map. The complex structure was finally refined to R = 19.4% including 207 solvent molecules. Although this complex crystal (Form II) was polymorphous as compared with the previously analysed one (Form I), the binding modes of leucine and isoamylamide moieties of E64-c were significantly different from each other. By the calculation of accessible surface area for each complex atom, these two different binding modes were both shown to be tight enough to prevent the access of solvent molecules to the papain active site. With respect to the E64-c-papain binding mode, molecular-dynamics simulations proposed two kinds of stationary states which were derived from the crystal structures of Forms I and II. One of these, which corresponds to the binding mode simulated from Form I, was essentially the same as that observed in the crystal structure, and the other was somewhat different from the crystal structure of Form II, especially with respect to the binding of the isoamylamide moiety with the papain S subsites. The substrate specificity for the papain active site is discussed on the basis of the present results.

Amino Acid Sequence↗
PubMed1992

Left-sided substrate binding of lysozyme: evidence for the involvement of asparagine-46 in the initial binding of substrate to chicken lysozyme.

The "right-sided" and "left-sided" substrate binding modes at the lower saccharide binding subsites (D-F sites) of chicken lysozyme were investigated by utilizing mutant lysozymes secreted from yeast. We constructed the following mutant lysozymes; "left-sided" substitution of Asn46 to Asp, deletion of Thr47, and insertion of Gly between Thr47 and Asp48 and "right-sided" substitution of Asn37 to Gly. Analyses of their activities and substrate binding abilities showed that Asn46 and Thr47 are involved in the initial enzyme-substrate complex and Asn37 is involved in the transition state. These results support an earlier proposal that interactions between substrate and residues at the left side of lysozyme stabilize a catalytically inactive enzyme-substrate complex, while interactions between substrate and residues at the right side stabilize the catalytically active complex [Pincus, M. R., & Scheraga, H. A. (1979) Macromolecules 12, 633-644]. These results are also consistent with the proposed kinetic mechanism for lysozyme reaction that the rearrangement of an initial enzyme-substrate complex (beta-complex) to another complex (gamma-complex) is required for catalytic hydrolysis [Banerjee S. K., Holler, E., Hess, G. P., & Rupley, J. A. (1975) J. Biol. Chem. 250, 4355-4367].

Amino Acid Sequence↗
PubMed1992

[MR imaging of thyroid masses].

Magnetic resonance (MR) imaging was performed in 35 patients with histologically proved thyroid masses. Gadopentetate dimeglumine was used in 25 of these cases. The thyroid tumors were analyzed by MR imaging as to shape, margin, pseudocapsulation, homogeneity, and enhanced pattern. Gd-DTPA was helpful in identifying pseudocapsules and showing the extent of the tumor. Papillary carcinoma tended to display unclear margins, heterogeneous intensity, and inhomogeneously enhanced patterns. In follicular adenoma, the tumor margin was smooth and pseudocapsules were clearly detected. Follicular adenoma was enhanced homogeneously, but it was difficult to distinguish follicular adenoma from follicular carcinoma by MR imaging. Adenomatous goiter was delineated as multiple nodules with smooth margins, but without pseudocapsules. These nodules were enhanced in various ways after Gd-DTPA administration.

Female↗