Biomedical subjects

M Inoue

Publications and source records attributed to M Inoue.

At least 73 records · Page 4Linked to original sources

PubMed1992

Construction of mutants of Actinobacillus actinomycetemcomitans defective in serotype b-specific polysaccharide antigen by insertion of transposon Tn916.

Mutants of Actinobacillus actinomycetemcomitans strain Y4 defective in the capsular-like serotype b-specific polysaccharide antigen (SPA) were constructed by inserting the transposon Tn916. Southern blot analysis suggested that the transposon was inserted into a variety of different sites on the chromosome. Whole cells from two mutants (strains ST1 and ST2) lacked reactivity with a monoclonal antibody to SPA of A. actinomycetemcomitans Y4 (mAb S5) in enzyme-linked immunosorbent assay, but those from another nine mutants (e.g. strains ST3 and ST5) reacted very weakly with mAb S5. Immunodiffusion tests showed that mAb S5 or rabbit antiserum against whole cells of strain Y4 produced a fused precipitin band with purified SPA and autoclaved extract from strain Y4, but no precipitin band with autoclaved extracts from these four mutants. The hydrolysate of autoclaved extract from strain Y4 contained equal amounts of rhamnose and fucose, component sugars of SPA. The hydrolysates of autoclaved extracts from strains ST1 and ST2 contained a trace amount of rhamnose, but not fucose. Those of autoclaved extracts from strains ST3 and ST5 contained a trace amount of fucose, but not rhamnose. All of these SPA-defective mutants reacted with a mAb to lipopolysaccharide of strain Y4. The cell hydrophobicity of SPA-defective mutants was higher than that of the parent strain. These mutant clones will be useful for analysing the gene complex responsible for the synthesis of SPA of A. actinomycetemcomitans and the regulation of expression of the polysaccharide.

Aggregatibacter actinomycetemcomitans↗

PubMed1992

Serological and biological characteristics of "Streptococcus milleri" isolates from systemic purulent infections.

Ninety-one Streptococcus milleri strains isolated from various systemic purulent lesions of 68 patients were examined by physiological and serological tests. Most strains formed a smooth colony (66 strains), did not form spontaneous aggregation of cells in BHI broth culture (79), were non-beta-haemolytic (alpha-35 or non-41), and belonged to biotype Ia (49) or Ib (34) and to API taxa S. milleri I (41) or II (38). Almost all of the beta-haemolytic strains as well as two-fifths of the non-beta-haemolytic belonged to API taxon I; strains of API taxa II and III were non-beta-haemolytic and non-haemolytic, respectively. Two-fifths (38) of the isolates belonged to one of eight serotypes, a-g and k, and more than half (47) to Lancefield groups A, C, F or G, the most frequent being type b (19) and group F (33). Fifteen strains carried simultaneously type a/group A, b/C, c/C, e/G, f/F or k/G antigens. Nineteen were neither typable nor groupable. All the 38 serotypable isolates were non-beta-haemolytic and not members of API taxon III, and were serologically and physiologically similar to oral S. milleri. The isolates from various infected sites--sputum, thorax, abdomen, urogenitalia, skin, eye and dental--exhibited distinct combinations of biological and serological properties. These results suggest that serotyping, haemolytic properties and API taxon, and their combinations, would be useful methods to trace oral S. milleri in systemic infections.

Abdomen↗

PubMed1992

Restricted distribution of Streptococcus milleri carbohydrate type antigens amongst other viridans streptococci.

The distribution of oral Streptococcus milleri carbohydrate type antigens in other viridans streptococcus species was examined. Rantz-Randall extracts of cells of the test strains grown in broth containing glucose were allowed to react with typing or grouping antisera for S. milleri serotypes a-k, or Lancefield groups A-G and K. Of 93 strains comprising more than 12 streptococcal species that included S. mutans and S. sanguis complexes, only 15 S. salivarius strains and one S. mitis strain were immunologically related to S. milleri serotype f. Unlike S. milleri strains, S. salivarius type f strains belonged to Lancefield group K, whereas the S. mitis strain was closely related to S. milleri serotype f but did not react with any of the Lancefield grouping antisera tested. Results suggest that oral S. milleri strains can be distinguished serologically from other oral viridans streptococci and that the typing antisera used in our researches might differentiate S. milleri isolates from the mouth from those associated with systemic purulent infections.

Antigens, Bacterial↗

PubMed1992

Differential expression of vinculin between weakly and highly metastatic B16-melanoma cell lines.

We previously reported on the altered expression of a third actin in mouse-B16 melanoma associated with malignant progression. While further investigating the relationship of cytoskeletal proteins to malignancy, we found that the expression of vinculin was higher in weakly metastatic B16-F1 cells than in highly metastatic B16-F10 cells. By Northern blot analysis, the mRNA expression of vinculin in B16-F1 was also shown to be higher than in B16-F10. Immunofluorescence staining showed a clear dotted distribution of vinculin in B16-F1, but only a weak and diffuse distribution in B16-F10. The dotted distribution tended to be larger in B16-F1 and when cultured on Matrigel and fibronectin than on laminin and type IV collagen. An alteration in the expression of vinculin was also observed in other cell systems. Vinculin was detected in both normal 3Y1 and in relatively weakly malignant transformed 3Y1 cell lines, while vinculin was either scarcely detected or not detected at all in more malignant cell lines. These results suggest that the suppression of vinculin is closely related to malignant progression in both the B16-melanoma and 3Y1 cell systems.

Actin Cytoskeleton↗

PubMed1992

Identification of antibodies against human papillomavirus type 16 E6 and E7 proteins in sera of patients with cervical neoplasias.

We have developed a sensitive and specific ELISA method using the s10-fusion proteins of human papillomavirus (HPV) 16 E6 and E7, expressed in E. coli. Sera from 97 women (30 patients with invasive cervical cancers, 26 patients with cervical intraepithelial neoplasia III (CIN III) and 38 healthy women) were tested for the presence of antibodies to E6 and E7 proteins. Eight (27%) of the 30 cervical cancer sera, five (19%) of the 26 CIN sera and none of the 38 normal sera were reactive with E6 proteins (cut-off point: absorbance (A) = 0.59, x +3SD). Ten (33%) of the 30 cervical cancer sera, two (8%) of the 26 CIN III sera and none of the 38 normal sera were reactive with E7 proteins (cut-off point: A = 0.40, x +3SD). The mean absorbance for anti-E7 antibody in positive cases was higher in cancer patients than in CIN III patients, while that for E6 did not differ between these two groups. Interestingly, six (50%) of 12 cancer sera which reacted with either E6 or E7 proteins were reactive for both proteins, whereas none of the sera from the CIN III patients reacted with both proteins. The high prevalence rates and high absorbance values for HPV 16 E6 and E7 antibodies in association with malignant transformation suggest that detection of these antibodies may be a useful diagnostic aid for cervical cancer-associated HPV 16.

Adult↗

PubMed1992

Mixed phenotype of blasts in acute megakaryocytic leukaemia and transient abnormal myelopoiesis in Down's syndrome.

Blasts from eight cases with acute megakaryoblastic leukaemia (AMKL) and seven with transient abnormal myelopoiesis in Down's syndrome (TAM) were investigated to clarify their phenotypic characteristics. CD41 and CD7 were the most frequently expressed in both disorders. CD41 was positive in six TAM and five AMKL cases, and CD7 was positive in five TAM and five AMKL cases, respectively. CD33 was detected in four TAM and five AMKL cases. Other myeloid-lineage associated antigens such as CD13 and CD11b could not be found in TAM but were expressed in five AMKL cases. Interestingly, CD56, a neural adhesion molecule, was expressed in three of four TAM and one of five AMKL cases. Cytoplasmic CD3 antigen was also noted in three of five examined cases. A short-term culture study was conducted on blasts from two TAM cases and five AMKL cases. In two cases in which CD41 was not expressed before culture, the expression of CD41 was enhanced after culture with or without 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The expression of CD7 remarkably was depressed, while that of CD13 was enhanced after culture with TPA. These findings suggest that blasts of TAM and AMKL originate from very immature cells and represent a mixed phenotype. In the present study, distinction of phenotypical differences between blast in TAM and AMKL was not possible.

Antigens, CD↗

PubMed1992

Crystal structure and molecular conformation of achatin-I (H-Gly-D-Phe-Ala-Asp-OH), an endogenous neuropeptide containing a D-amino acid residue.

In order to investigate the active conformation of achatin-I (H-Gly-D-Phe-Ala-Asp-OH), an endogenous neuropeptide from the Achatina fulica ganglia, its crystal structure and molecular conformation were analysed by the X-ray diffraction method. Crystals from methanol/dioxane are monoclinic, space group P2(1) with a = 5.083(1), b = 9.125(1), c = 20.939(3) A, beta = 94.73(1) degrees. The structure was solved by direct methods and refined to R = 0.051 for 1714 independent reflections with /Fo/ greater than sigma (Fo). The molecule exists as a zwitterion with the Gly N-terminal end protonated and Asp beta-carboxyl deprotonated; the C-terminal of Asp is in a neutral state. The molecule takes a kind of beta turn structure with the D-Phe-Ala residues at the corner of the bend. This turn conformation is primarily formed by the strong intramolecular hydrogen bonds of NH(Gly)...O delta 1 (Asp) and NH(Asp)...O delta 1 (Asp) pairs, thus forming a 15-membered ring structure. Judging from the published data concerning the structure-activity relationship, this turn conformation may reflect an important feature related to the neuroexcitatory activity of achatin-I.

Amino Acid Sequence↗

PubMed1992

Slow kinetic property of mexiletine in guinea pig atrium.

We studied the onset and offset of use-dependent block (UDB) of maximum rate of rise of action potential (Vmax) with 3 x 10(-5)M mexilietine in guinea pig left atrium. A large decrease of Vmax was observed between the first and the second excitation when the preparations were stimulated at 4Hz after two minutes of rest period. UDB after the second excitation developed slowly to reach steady state within 30 sec. These two onset rates were 1.016 +/- 0.055 and 0.070 +/- 0.009/action potential. Recovery process was also fitted with two exponential equations. The time constant of the fast recovery was 528 +/- 23 msec. and the slow one was 3099 +/- 435 msec. The relative contribution of the slow component was 38.3 +/- 2.6% in the onset and 29.7 +/- 3.1% in the recovery. In spite of elevated maximum diastolic potential at 4 Hz stimulation, the relationship between resting membrane potential and Vmax disclosed voltage-dependent block of Vmax was no more than 5%. It is concluded that mexiletine has a slow kinetic component as well as a fast one. When atrial muscle is depolarized, Vmax decreases further. Therefore, mexiletine may be more effective against the atrial arrhythmias than predicted previously.

Action Potentials↗

PubMed1992

Acute and subacute effects of doxorubicin on postextrasystolic potentiation in guinea pig papillary muscles.

To investigate the effects of doxorubicin on postextrasystolic potentiation (PESP), isolated guinea pig papillary muscles were field-stimulated and the resulting isometric force was recorded. Postextrasystolic contraction was evoked following trains of 37 regular stimulations. The effects of acute doses of doxorubicin (0.2 mM) on regular contractions and postextrasystolic contractions were examined for 2 hr. The effects of subacute doses of doxorubicin (total dose 5 mg/kg intraperitoneally) on the relationship between %PESP (postextrasystolic/regular contraction) and both the extra-stimulus coupling interval and the postextrasystolic interval were examined. Acute administration of doxorubicin decreased the amplitude of postextrasystolic contractions more than that of regular contractions. Thus, %PESP in the doxorubicin-treated group decreased significantly over time. There was no similar decrease in the control papillary muscles. Both the extra-stimulus coupling interval and the postextrasystolic interval had less of an effect on %PESP in doxorubicin-treated animals than in control animals. Since PESP depends upon sarcoplasmic reticulum activity, our results indicate that acute and subacute exposure to doxorubicin impairs the activity of the sarcoplasmic reticulum of guinea pig papillary muscles.

Animals↗

PubMed1992

Effect of mammalian lignans on fMLP-induced oxidative bursts in human polymorphonuclear leucocytes.

We examined the effects of mammalian lignans, enterolactone, prestegane B and 2,3-dibenzylbutane-1,4-diol (DBB) on superoxide production and luminol-dependent chemiluminescence (LCL) response in human polymorphonuclear leucocytes (PMNs). The three lignans had no direct effect on the responses of human PMNs. DBB and prestegane B enhanced the superoxide production and LCL response induced by formylmethionyl-leucyl-phenylalanine (fMLP), but enterolactone inhibited fMLP-induced effects. The effects of DBB were stronger than those of prestegane B and the effects of DBB were inhibited by bromophenacyl bromide, mepacrine, N-(6-aminophenyl)-5-chloro-1-naphthalene, sulphonamide and trifluoroperazine, but not by gossypol, nordihydroguaretic acid, indomethacin, staurosporine, 1-(5-isoquinolinesulphonyl)-2-methylpiperazine dihydrochloride or (R,S)-2-methoxy-3-(octadecyl-carbamoyloxy)-propyl-2-(2-thiazoli o)-ethylphosphate. These results suggest that DBB primes the responses of human PMNs, and the priming effect is caused by the activation of phospholipase A2--and Ca(2+)-calmodulin-pathways, but not by the activation of lipoxygenase, cyclo-oxygenase and protein kinase C or by the release of platelet activating factor.

Humans↗

PubMed1992

In vitro activity of T-3761, a new fluoroquinolone.

The in vitro activity of T-3761, a new fluoroquinolone antimicrobial agent which has an oxazine ring structure with a cyclopropyl moiety at C-10, was compared with those of other agents against 2,854 clinical isolates. T-3761 had a broad spectrum of activity and had potent activity against gram-positive and -negative bacteria. The MICs of T-3761 against 90% of the methicillin-susceptible Staphylococcus aureus, methicillin-susceptible and -resistant Staphylococcus epidermidis, and Clostridium spp. tested were 0.39 to 6.25 micrograms/ml. Its activity was comparable to those of ciprofloxacin and ofloxacin and four- to eightfold greater than those of norfloxacin and fleroxacin, but its activity was two- to eightfold less than that of tosufloxacin. Some isolates of ciprofloxacin-resistant S. aureus (MIC of ciprofloxacin, greater than or equal to 3.13 micrograms/ml) were still susceptible to T-3761 (MIC of T-3761, less than or equal to 0.78 micrograms/ml). The MICs of T-3761 against 90% of the streptococci and enterococci tested were 3.13 to 100 micrograms/ml. Its activity was equal to or 2- or 4-fold greater than those of norfloxacin and fleroxacin, equal to or 2- or 4-fold less than those of ofloxacin and ciprofloxacin, and 4- to 16-fold less than that of tosufloxacin. The activity of T-3761 against gram-negative bacteria was usually fourfold greater than those of norfloxacin, ofloxacin, and fleroxacin. Many isolates which were resistant to nonfluoroquinolone agents, such as minocycline- or imipenem-resistant S. aureus, ceftazidime-resistant members of the family Enterobacteriaceae, gentamicin- or imipenem-resistant Pseudomonas aeruginosa, and ampicillin-resistant Haemophilus influenzae and Neisseria gonorrhoeae, were susceptible to T-3761. The MBCs of T-3761 were either equal to or twofold greater than the MICs. The number of viable cells decreased rapidly during incubation with T-3761 at one to four times the MIC. At a concentration of four times the MIC, the frequencies of appearance of spontaneous mutants resistant to T-3761 against S. aureus, Escherichia coli, Serratia marcescens, and P. aeruginosa were 2.2 x 10(-8) to less than or equal to 1.2 x 10(-9). The 50% inhibitory concentrations of T-3761 for DNA gyrases isolated from E. coli and P. aeruginosa were 0.88 and 1.9 micrograms/ml, respectively.

Anti-Infective Agents↗

PubMed1992

Lack of effect of carbonyl cyanide m-chlorophenylhydrazone on KB-5246 accumulation by Staphylococcus aureus.

The accumulation of KB-5246 in a quinolone-susceptible strain of Staphylococcus aureus was about 70 times that of norfloxacin. Carbonyl cyanide m-chlorophenylhydrazone increased the accumulation of norfloxacin about eightfold, but it did not influence that of KB-5246. The low efflux of KB-5246 from S. aureus may contribute to its potent antibacterial activity.

Anti-Infective Agents↗

PubMed1992

Detection and identification of Yersinia pseudotuberculosis and pathogenic Yersinia enterocolitica by an improved polymerase chain reaction method.

We developed a polymerase chain reaction method in order to detect and identify both Yersinia pseudotuberculosis and pathogenic Yersinia enterocolitica. Polymerase chain reaction was performed by using a mixture of primers against the inv gene from Y. pseudotuberculosis and the ail gene from pathogenic Y. enterocolitica. Further addition of primers against the plasmid-coded virF gene from Y. enterocolitica made it possible to detect a virulence-associated gene of both species at the same time. This method was proved to be an adequate and convenient procedure for routine detection and identification of these bacilli.

Animals↗

PubMed1992

Delayed shortening and shrinkage of cochlear outer hair cells.

Slow shortening of cochlear outer hair cells has been speculated to modify cochlear sensitivity. Tetanic electrical field stimulation of isolated outer hair cells from guinea pigs shortened the cells for 2-3 min. Electrical stimulation reduced cell length and volume (-13.5 +/- 1.5 and -37.3 +/- 3.0% of initial values, respectively, n = 16) and decreased the intracellular Cl- concentration. Cytochalasin B (100 microM) inhibited electrical stimulation-induced shortening but not volume reduction. The following chemicals or manipulations inhibited the responses: 10 microM furosemide, 0.1 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), 1 mM anthracene-9-carboxylic acid (AC9), 25 mM tetraethylammonium, 2.3 microM charybdotoxin (ChTX), 250 nM omega-conotoxin, and Ca(2+)-free medium. These findings suggest that both electrical stimulation-induced shortening and shrinkage of outer hair cells result not only from an actin-mediated contractile force, but also from Cl- efflux through furosemide-, DIDS-, and AC9-sensitive Cl- channels, and K+ efflux through ChTX-sensitive K+ channels.

Actins↗

PubMed1992

Interaction of ANP with endothelin on cardiovascular, renal, and endocrine function.

To assess the interaction of endothelin (ET) with atrial natriuretic peptide (ANP) on cardiovascular and renal function, arginine vasopressin (AVP) release, and the renin-angiotensin-aldosterone system, either a low or high dose of ET (4 or 12 pmol.kg-1.min-1) was administered with ANP (26 pmol.kg-1.min-1) for 45 min after the initial infusion of ANP alone in anesthetized dogs. In the other groups, either ANP or saline alone was administered for 90 min. ANP alone decreased blood pressure (BP), cardiac output (CO), plasma aldosterone, and plasma renin activity (PRA), increased urinary Na and K excretion (UNaV and UKV, respectively) and urine flow (UF), but did not affect plasma AVP. The low dose of ET had no effect on these ANP-induced changes. However, the high dose of ET curtailed the responses to ANP, increased BP and PRA, and decreased UNaV, UKV, and UF associated with decreased renal plasma flow and glomerular filtration rate. High ET also further potentiated the decrease in CO and the increase in total peripheral resistance induced by ANP and increased plasma AVP. These results indicate that a dose of ET one-half that of ANP (on the molar ratio) may have completely counteracted vascular, hormonal, and renal responses to ANP.

Aldosterone↗

PubMed1992

Central effects of endothelin-1 on vasopressin release, blood pressure, and renal solute excretion.

To assess central effects of endothelin-1 (ET-1) on plasma arginine vasopressin (AVP), plasma atrial natriuretic peptide (ANP), blood pressure, heart rate, and renal solute excretion, ET-1 dissolved in the artificial cerebrospinal fluid was infused intracerebroventricularly (icv) at a dose of either 0.35 ng.kg-1.min-1 (0.14 pmol; LET) or 3.5 ng.kg-1.min-1 (1.4 pmol; HET) for 45 min in conscious rats. In the control study, ET-1 was omitted from the vehicle. Moreover, [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid),2-O-methyl-tyrosine]AVP (TMeAVP), a V1-blocker, and prazosin, an alpha 1-blocker, were peripherally administered. In the LET group, mean arterial blood pressure (MABP) increased without any changes in heart rate, plasma AVP and ANP, and renal solute excretion. In the HET group, MABP markedly increased with rises in plasma AVP and ANP, but urine flow, urinary osmolality, and urinary Na and K excretion decreased. TMeAVP attenuated the pressor response to ET-1, abolished rises in plasma ANP, and partially restored falls in urine flow. Prazosin after TMeAVP obviated the pressor response to ET-1. In the control, these parameters did not change, except for an increase in urinary solute excretion. These results showed that icv ET-1 stimulates the sympathetic nervous activity and plasma AVP, leading to increased blood pressure and renal vasoconstriction, with a reduction in renal water and electrolyte excretion.

Analysis of Variance↗

PubMed1992

Neutrophil accumulation in ischemic reperfused rat liver: evidence for a role for superoxide free radicals.

Oxygen-derived free radicals and leukocytes have been implicated in the pathogenesis of ischemia-reperfusion injury. This study aimed at determining, by using biochemical and histochemical techniques, whether an accumulation of neutrophils occurs in the ischemic reperfused rat liver and whether superoxide free radicals play a role in mediating this neutrophil accumulation. Hepatic ischemia was induced by occluding blood supply to the left and median lobes, and reperfusion was reinstituted by releasing the occlusion. Myeloperoxidase activity of the liver was measured with a tetramethylbenzidine-H2O2 assay after removal of glutathione (by dialysis) and in the presence of 3-aminotriazole (catalase inhibitor). A modification of Graham and Karnovsky's method was used to stain neutrophils in liver frozen sections, and the number of neutrophils was counted. Results showed that ischemia-reperfusion of the liver produced a 4.4-fold increase in myeloperoxidase activity (from 0.073 +/- 0.009 to 0.320 +/- 0.017 units/mg liver, means +/- SE), which was proportional to the number of neutrophils (3.1-fold increase from 18 +/- 7 to 57 +/- 4 cells/mm2) in the liver tissue. Pretreatment with long-acting superoxide dismutase significantly attenuated the elevated myeloperoxidase activity and the number of neutrophils. These results indicate that reperfusion after a period of ischemia induces an accumulation of neutrophils in the liver, and superoxide anion free radicals are important mediators in the mechanism of this neutrophil accumulation.

Animals↗

PubMed1992

Endogenous adenosine blunts beta-adrenoceptor-mediated inotropic response in hypoperfused canine myocardium.

BACKGROUND: Adenosine attenuates beta-adrenoceptor-mediated inotropic responses through GTP-binding protein in vitro. The goal of the present study was to test the hypothesis that endogenous adenosine released from the ischemic myocardium blunts the inotropic response to beta-adrenergic stimulation. METHODS AND RESULTS: In 45 open-chest dogs, the left anterior descending coronary artery was perfused through an extracorporeal bypass tube from the carotid artery. Coronary perfusion pressure was reduced so that coronary blood flow was decreased to 60% of the basal level by partial occlusion of the bypass tube, and the reduced coronary perfusion pressure was kept constant thereafter. Inotropic responses to isoproterenol were assessed by fractional shortening of the myocardium in the perfused area. After the onset of hypoperfusion, lactate extraction ratio (18.8 +/- 1.2%) and fractional shortening (20.7 +/- 1.1%) were significantly decreased to -8.4 +/- 8.0% and 5.9 +/- 1.5%, respectively, and coronary arteriovenous differences of adenosine were increased from 4.6 +/- 3.6 to 89.4 +/- 10.5 pmol/ml. In the untreated condition, an intravenous infusion of isoproterenol (150 ng/kg/min) augmented fractional shortening from 5.9 +/- 1.5% to 13.6 +/- 0.8%. When adenosine release was attenuated by administration of prazosin (4 micrograms/kg/min i.c.) during hypoperfusion, the response of fractional shortening to isoproterenol (from 5.3 +/- 1.2% to 20.5 +/- 1.4%) was much greater (p less than 0.05) than that in the untreated control condition. Exogenous administration of adenosine significantly attenuated the inotropic response to isoproterenol in the prazosin-treated hearts. In contrast, an adenosine receptor antagonist, 8-phenyltheophylline, also enhanced the inotropic response to isoproterenol. The attenuation of beta-adrenoceptor-mediated inotropic response by adenosine could not be attributed to the inhibition of norepinephrine release from the sympathetic nerve endings, because identical results were observed in the chemically denervated hearts. CONCLUSIONS: Endogenous adenosine released from the ischemic myocardium attenuates beta-adrenoceptor-mediated inotropic response in the ischemic heart.

Adenosine↗