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Biomedical subjects

S Miyazaki

Publications and source records attributed to S Miyazaki.

At least 487 records · Page 27Linked to original sources
PubMed1992

Separate isolation of Clostridium difficile spores and vegetative cells from the feces of newborn infants.

A modified taurocholate-cefoxitin-cycloserine-fructose agar medium, pH 5.5, on which vegetative cells alone could grow, was newly devised for separate isolation of Clostridium difficile vegetative cells and spores from feces. The ratio of C. difficile-positive feces from healthy newborn infants younger than 10 days of the age was 30.8%, and 93.3% of feces from healthy infants older than 20 days were positive for C. difficile. C. difficile spores alone were detected in twenty-one samples (75%) of C. difficile-positive Twenty-eight specimens. Only 10.7% (3/28) C. difficile vegetative cells alone were detected. C. difficile spores alone were detected in one of nine healthy adults. These collective results offer potential explanations for high frequent isolations of C. difficile from newborn infants without occurrence of pseudomembranous colitis.

Bottle Feeding↗
PubMed1992

The other mediator for adherence of Haemophilus influenzae organisms without involvement of fimbriae.

The number of the nontypeable Haemophilus influenzae (HiN) organisms that adhered to the primary mouse fetal lung cells was significantly more than type b Haemophilus influenzae (Hib) organisms. The average number of HiN organisms adherent to host cells was 2,291/100 host cells (range, 1,654-3,182), but that of Hib was markedly reduced to 147/100 host cells (range, 102-238). In this case, P value was less than 0.05 by using a paired Student t-test. The sonicated extract from HiN TMS11 organisms inhibited adherence of H. influenzae TMS11 organisms to monolayer at 76.3% and it inhibited adherence of Hib TMS24 organisms at 92.3%. This result indicates that a mediator existing on the surface of HiN organisms may be the same as that on type b organisms. The number of detected organisms in broncho and lung tissues 3 days after intranasal infection with HiN strains was significantly greater than that in infection with Hib strains. Therefore, in vitro adhesive capacity of H. influenzae organisms was correlative to infectivity by intranasal injection.

Animals↗
PubMed1992

T cell activation and T cell receptor variable region gene usage in measles.

T cell activation and T cell receptor variable (V) regions were studied with monoclonal antibodies in peripheral blood lymphocytes from 22 patients with measles. Increased (greater than 5%) activated T cells (HLA-DR+ CD3+ cells) were noted in 14 of the 22 patients. Elevations of V beta 5+ and V beta 8+ T cells were observed in two and four patients, respectively, and appeared to be associated with T cell activation. The duration of fever was significantly prolonged in those with increased (greater than 10%) activated T cells (p less than 0.01). These results suggest that T cell activation and the preferential expansion of V beta 8+ and V beta 5+ T cells are associated with the pathogenic process of measles.

Adolescent↗
PubMed1992

The pH dependent uptake of enoxacin by rat intestinal brush-border membrane vesicles.

The mechanism of the intestinal transport of enoxacin, an orally active fluoroquinolone antibiotic, has been investigated using brush-border membrane vesicles isolated from rat small intestine. The initial rate and time-course of enoxacin uptake were considerably dependent upon the medium pH (pH 5.5 greater than pH 7.5) and upon the percent ionization of the carboxyl group (pKa 6.2, anionic charge), namely, the degree of uptake of cationic form was higher than that of the zwitterionic form. There was evidence of transport into the intravesicular space as shown by the effect of extravesicular medium osmolarity on enoxacin uptake at steady state (30 min). This transport across the brush-border membrane was stimulated by the valinomycin-induced K(+)-diffusion potential (interior negative) and an outward H(+)-diffusion potential. Furthermore, changing the pH of the medium from 5.5 to 7.5 significantly decreased the effect of valinomycin-induced K(+)-diffusion potential on the enoxacin uptake. These results suggest that the uptake behaviour of the cationic form of enoxacin plays an important role in the intestinal absorption process of enoxacin.

Animals↗
PubMed1992

[A case of tracho-bronchial aspergillosis complicated with acute myeloblastic leukemia].

A 59-year-old male was admitted to our hospital in Jan. 1991 with complaints of general malaise and palpitation. Laboratory findings on admission showed anemia, thrombocytopenia and leukopenia consisted of 2.0% myeloblasts with Auerbodies. The bone marrow study showed granuloid hyperplasia with 45.5% myeloblasts. The diagnosis of acute myeloblastic leukemia (M1) was made. After BHAC-AMP therapy, he obtained complete remission. However, he complained of fever and cough, and his chest X ray film showed a focal infiltrative shadow in the right upper lung field. Antibiotics for bacteria and fungus were administered and the abnormal shadow improved in a week. However, as he had hemosputum, the bronchoscopic examination was performed, and multiple ulcers covered by yellow-white tissue were revealed on the wall of the trachea and bilateral main bronchi. Biopsy specimens obtained by transbronchial biopsy showed bronchial aspergillosis. Though intravenous infusion and inhalation of amphotericin B were effective for aspergillosis, he had a relapse of the leukemia and died in autumn, 1991.

Aspergillosis↗
PubMed1992

[Changes in serotypes of clinical isolates of Pseudomonas aeruginosa by anti-pseudomonal drugs].

Forty-two isolates of P. aeruginosa from various infections were each incubated in Mueller-Hinton broth including piperacillin, cefsulodin, ceftazidime, imipenem, gentamicin or norfloxacin (1MIC-4MIC) at 35 degrees C for 18 hours, and serotyped using monoclonal antibodies. Serotypes of 4 (9.5%)-8 (19.0%) of the 42 isolates each changed to different groups after incubation. No relationship was found between serotypes of the formed variants and anti-pseudomonal drugs used. When P. aeruginosa TA-2 was exposed to cefsulodin at different concentrations (1MIC and 2MIC) under the above conditions, the distinct variants different in serotypes were formed according to the drug concentrations. Furthermore, P. aeruginosa TA-2 and TA-13 were incubated in Mueller-Hinton broth including cefsulodin (1/2 or 2MIC) and gentamicin (1/2MIC), respectively, and the growth curves of parent and variant cells were determined. In the experiments, the variants appeared 6 hours after onset of the incubation and grew with the parents. The present results may explain our findings previously reported; coexistence of colonies different in serotype of P. aeruginosa isolated from some individual patients. The results indicate the possibility that alteration in bacterial surfaces in association with changes in serotypes might occur in vivo in these patients infected with P. aeruginosa and treated with anti-pseudomonal drugs.

Anti-Bacterial Agents↗
PubMed1992

[The study of pathogenic mechanisms of chronic Pseudomonas aeruginosa lung infections by mucoid strains].

Chronic Pseudomonas aeruginosa lung infection with mucoid strains is the predominant cause of death in cystic fibrosis (CF) or diffuse panbronchiolitis (DPB). This infection is characterized by a chronic course without spread of the bacteria to the blood when compared with other infections due to the non-mucoid strains. However, the mechanism of P. aeruginosa lung infection with the mucoid strains remains obscure. Intra-tracheal and systemic infection in mice, susceptibility to the bactericidal activity of fresh human and mouse serum, and adherent activity to mouse fetal lung cell were examined for mucoid and non-mucoid strains of P. aeruginosa. After intra-tracheal infection, the mucoid strains were distributed to other organs anormously but not the non-mucoid stains, and the bacterial number of the mucoid strains in the blood were significantly lower than that of the non-mucoid strains. On the other hand, when these strains were inoculated into the tail vein of mouse, the mucoid strain was eliminated more rapidly from blood as compared with the non-mucoid strain. The mucoid strains showed reduced bacteremic virulence when compared with non-mucoid strains with a 50% lethal dose (LD50) of 1.5 x 10(7) CFU/mouse as the mean value in a systemic infection. In contrast to the non-mucoid strains, the mucoid strains were sensitive to human fresh serum but were resistant to mouse fresh serum. The mucoid strains adhered to the monolayer of the mouse fetal lung cell 7-fold better than did non-mucoid strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

In vitro and in vivo antibacterial activities of a new quinolone, OPC-17116.

The in vitro and in vivo antibacterial activities of OPC-17116 were compared with those of ofloxacin, enoxacin, ciprofloxacin, and tosufloxacin. The MICs of OPC-17116 for 90% of the strains tested were 0.125 to 8 micrograms/ml against gram-positive bacteria such as members of the genera Staphylococcus, Streptococcus, and Enterococcus: less than or equal to 0.063 to 16 micrograms/ml against members of the family Enterobacteriaceae; and less than or equal to 0.063 to 16 micrograms/ml against glucose-nonfermentative bacilli such as Pseudomonas aeruginosa. The activity of OPC-17116 against gram-positive organisms was comparable to that of tosufloxacin and higher than those of other reference drugs. The in vitro activity of OPC-17116 against gram-negative bacteria was similar to those of the reference drugs. In experimental systemic infections in mice with various organisms, the efficacy of OPC-17116 was similar to that of tosufloxacin and greater than those of ofloxacin, enoxacin, and ciprofloxacin. In a pyelonephritic model in mice with P. aeruginosa KU-1, OPC-17116 was as active as ciprofloxacin and more active than ofloxacin, enoxacin, and tosufloxacin. In respiratory tract infections in mice with Staphylococcus aureus Smith, Streptococcus pneumoniae TMS 3, and Klebsiella pneumoniae 3K25, the efficacy of OPC-17116 was generally greater than that of tosufloxacin. The peak level of OPC-17116 in the lungs of mice was 10 times higher than that in serum and was significantly greater than levels in lung achieved with an equivalent dose of the other quinolones. The therapeutic efficacy of OPC-17116 may depend not only on its in vitro activity but also on its high concentration in tissue.

Administration, Oral↗
PubMed1992

Influence of the force-frequency relation on left ventricular function during exercise in conscious dogs.

BACKGROUND: The magnitude of the force-frequency effect on myocardial contractility in the conscious animal has been studied at rest, but it has not been assessed during exercise. METHODS AND RESULTS: The influence of heart rate (HR) changes were evaluated during treadmill exercise in eight preinstrumented, conscious dogs in which high-fidelity left ventricular (LV) pressure, LV volume (by sonomicrometry), and aortic pressure were measured. Under resting conditions, end-systolic pressure-volume relations were obtained using inferior vena caval occlusion. Dogs were run on a treadmill, and the intrinsic exercise HR was reduced by infusion of a specific bradycardic drug (UL-FS 49 0.5 mg/kg) during continuing exercise while HR was maintained at 240 beats per minute by atrial pacing. At 6 minutes of running at a fixed, paced HR when a stable drug effect had been achieved, no effects of UL-FS 49 on measures of LV contractility were detected compared with exercise before drug administration. HR was then reduced stepwise from 240 to 210, 180, or 150 beats per minute in a random manner, returning to 240 beats per minute between steps. Progressive reductions in measures of myocardial contractility occurred as the HR was slowed, and reduction of rate from 240 to 150 beats per minute reduced the LV maximum positive dP/dt by 31% and (dP/dt)DP40 by 21% despite increases in LV end-diastolic pressure. The entire end-systolic pressure-volume could not be determined during exercise, but beat-averaged end-systolic pressure-volume points during exercise were progressively shifted to the right and downward by slowing the exercise HR. Thus, a pronounced negative inotropic influence of slowing the heart was observed during exercise, and the rate of ventricular relaxation (tau) was also significantly prolonged. CONCLUSIONS: These findings indicate that force-frequency effects on the inotropic state of the intact LV are markedly enhanced by exercise.

Animals↗
PubMed1992

Antitumor effect of pluronic F-127 gel containing mitomycin C on sarcoma-180 ascites tumor in mice.

Pluronic F-127 (PLF-127) gels were evaluated as a sustained-release vehicle for intraperitoneal administration of mitomycin C (MMC) in order to enhance the therapeutic effects of MMC against a Sarcoma-180 ascites tumor in mice. Tumor cell injections were made on day 0 and injections of MMC in 25% (w/w) PLF-127 on day 1, both intraperitoneally. A prolongation of the life span of tumor-bearing mice following injection of therapeutic PLF-127 was noted, and PLF-127 containing MMC was therapeutically more active than free drug. The high chemotherapeutic efficiency of MMC in PLF-127 was striking at high doses, which would be toxic in the case of the drug alone. PLF-127 gels exhibit reverse thermal behavior and are fluid at refrigerator temperature, but are soft gels at body temperature. The in vitro release experiments indicated that Pluronic gel might serve as a rate-controlling barrier and be useful as a vehicle for sustained-release preparations of MMC to be administered intraperitoneally. These results suggest that sustained-release occurs in the peritoneum and that effective drug concentrations can be maintained by the preparation.

Animals↗
PubMed1992

External control of drug release and penetration. VI. Enhancing effect of ultrasound on the transdermal absorption of indomethacin from an ointment in rats.

The effect of an ultrasound (1 MHz) on transdermal absorption of indomethacin from an ointment was studied in rats. Ultrasound energy was supplied for between 5 and 20 min at a range of intensities (0.25, 0.5, 0.75, and 1 W cm-2), energy levels commonly used for therapeutic purposes. For evaluating skin penetration of indomethacin, the change of plasma concentration was measured. The pronounced effect of ultrasound on the transdermal absorption of indomethacin was observed at all ultrasound energy levels studied. The intensity and the time of application were found to play an important role in the transdermal phonophoretic delivery system of indomethacin; 0.75 W cm-2 appeared to be the most effective intensity in improving the transdermal absorption of indomethacin, while the 10 min ultrasound treatment was the most effective. Although the highest penetration was observed at an intensity of 0.75 W cm-2, 0.5 W cm-2 was preferred because intensities of less than 0.5 W cm-2 of ultrasound for 10 min did not result in any significant skin temperature rise nor did it have any destructive effect on rat skin. Progressively more skin damage was noted as the intensity and the time of application of ultrasound increased. When used at a proper intensity and time of application, ultrasound appears to be a safe technique for enhancing the passage of various drug molecules through human skin.

Administration, Cutaneous↗
PubMed1992

[The mechanism of the renal excretion of disopyramide in rats. I].

The mechanism involved in the renal excretion of disopyramide (DPM) is still incompletely understood. The purpose of this study was to examine the renal handling of DPM and the interactions between DPM and several organic anionic or cationic drugs related to the renal tubular secretion, using the renal clearance and renal cortical slices uptake techniques in rats. The clearance ratio of DPM was greater than that of glomerular filtration and this suggests the tubular secretion of DPM. The clearance ratio of DPM did not change after infusion of either anionic drugs (p-aminohippurate and probenecid) or a cationic drug (cimetidine). The results of time and concentration-dependent experiments using renal cortical slices demonstrated that DPM was accumulated against a concentration gradient by a saturable process. Inhibition of uptake by 2,4-dinitrophenol and cyanide indicated an energy dependence. DPM uptake was considerably inhibited by the cationic drugs, cimetidine and quinine, suggesting that DPM was transported by the cation transport mechanism. Probenecid, a competitor for the anion transport mechanism, moderately inhibited DPM uptake.

Animals↗
PubMed1992

Pathogenesis, treatment and prognosis of impending myocardial infarction and early post-infarction angina--relation between ST-segment shift during myocardial ischemia and the pathogenesis.

We studied 141 patients to evaluate the pathogenesis and clinical picture of high-risk unstable angina (UA), designated as impending myocardial infarction (IMI) in this study, or severe early post-infarction angina (PIA). IMI and PIA were diagnosed when chest pain appeared at rest and lasted 15 min or more despite extensive pharmacological therapy during hospital stay among consecutive 510 patients with UA. All patients underwent coronary angiography urgently within 72 h after chest pain, and were divided into 2 subgroups according to ST segment shifts during chest pain. In IMI, 42 patients with ST depression had higher incidences of prior myocardial infarction (MI), worsening UA, multivessel disease and complex lesions such as eccentric irregular lesion or ulceration. On the contrary, in 44 with ST elevation, new onset UA, single vessel disease and coronary thrombus (CT) were dominant. In PIA, 32 patients with ST elevation revealed higher incidences in Q wave MI, ST elevation at the MI onset, single vessel disease and CT, compared to 23 with ST depression who showed a high proportion of complex lesions. Thus, it was evident that there was a common link between the pathogenesis of IMI and PIA. The therapeutic options were also different in the groups according to ST segment shift. We conclude that ST segment shifts during chest pain may be useful for determining the pathogenesis and clinical features of high-risk UA.

Angina, Unstable↗
PubMed1992

Isolation and characterization of type 1 fimbriae from a chicken pathogenic Escherichia coli serotype O78.

Type 1 fimbriae from chicken pathogenic Escherichia coli strain PDI-386 (serotype O78) was purified and characterized. Because of the acid-induced autoagglutination (T. Sekizaki, Y. Nakasato, and I. Nonomura, J. Vet. Med. Sci. 54, 493-499, 1992), the fimbriae could be easily purified by repeating acid sedimentation, washing, and dissolving in buffer (pH 8.0). In electron microscopy, the purified fimbriae showed a filament of 8 nm in diameter and 10 microns in average length. The molecular mass of the protein subunit of the purified fimbriae estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 19,000 daltons. The amino acid composition and its NH2-terminal sequence were similar to the previously described one of the Klebsiella pneumoniae type 1 fimbriae. Moreover, there was an immunological relatedness between them. These results indicated that a molecular diversity found between the fimbriae of E. coli and that of K. pneumoniae has already been existed among chicken pathogenic E. coli strains.

Amino Acid Sequence↗
PubMed1992

Prorenin-renin axis in synovial fluid in patients with rheumatoid arthritis and osteoarthritis.

This study was undertaken 1) to determine whether or not renin is present in synovial fluid in patients with rheumatoid arthritis and osteoarthritis, and, if present, 2) to investigate whether it is synthesized in synovial fluid, or it is only transported from the circulation into the synovial cavity. The active renin concentration (indirect) was measured with angiotensin I radioimmunoassay kits. Inactive renin was converted into active renin with Sepharose-bound trypsin. Both active and inactive forms of renin were found in synovial fluid. They were significantly higher in patients with rheumatoid arthritis (n = 9) than in those with osteoarthritis (n = 16). In plasma, the concentration of inactive renin was significantly higher (P less than 0.001) in the former. Albumin, transferrin, alpha 2-macroglobulin, ceruloplasmin and immunoglobulins G and M were also found in synovial fluid. In each disease, a plot of the log ratio of synovial fluid to the serum concentration against the log molecular weight of each protein gave an approximately straight line curve, suggesting that these proteins are derived from the circulation and are transported into the synovial cavity. In contrast, the ratio of synovial fluid to plasma concentrations of active renin was significantly higher than that predicted on the basis of the above-mentioned interrelationships in both diseases, whereas the ratio of inactive renin was significantly lower. These findings suggest that 1) inactive and active renin are filtered into the synovial fluid from the circulation, and that 2) inactive renin is converted into the active form in the fluid.

Aged↗
PubMed1992

Secretory regulation of 19-hydroxyandrostenedione in normal man.

To evaluate the secretory regulation of 19-hydroxyandrostenedione (19-OH-AD), its plasma concentration was measured before and after stimulation and inhibition tests for the ACTH-adrenal axis and the renin-angiotensin system in 50 normal subjects. Basal levels of plasma 19-OH-AD did not correlate with either those of plasma renin activity (PRA) or the plasma aldosterone concentration (PAC), but positively correlated with those of plasma cortisol. Plasma 19-OH-AD was stimulated by 0.25 mg ACTH-(1-24) and was suppressed by 1 mg dexamethasone (DEX) as were plasma cortisol and PAC. On the other hand, with 2-h standing alone or iv 40 mg furosemide plus 2-h standing, plasma 19-OH-AD and cortisol did not increase but PRA and PAC did. With iv furosemide plus 2-h standing with 3 mg DEX pretreatment, plasma 19-OH-AD and cortisol did not respond either, but PRA and PAC increased. With 25 mg oral captopril following 1-h standing with 3 mg DEX pretreatment, plasma 19-OH-AD and cortisol did not change but PAC decreased. These results indicate that the secretion of 19-OH-AD is mainly under the control of the ACTH-adrenal axis rather than the renin-angiotensin system.

Adolescent↗