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Biomedical subjects

A Nagayama

Publications and source records attributed to A Nagayama.

At least 19 recordsLinked to original sources
PubMed2002

In vitro antibacterial activity of S-4661, a new parenteral carbapenem, against urological pathogens isolated from patients with complicated urinary tract infections.

The antibacterial activity of S-4661, a new parenteral carbapenem antibiotic, was assessed against the major urological pathogens isolated from patients with complicated urinary tract infections. S-4661 was slightly less active than imipenem and panipenem, but more active than meropenem and ceftazidime against Gram-positive bacteria. Against Gram-negative bacteria, S-4661 was similar to meropenem, similar to or more effective than imipenem, and more active than panipenem and ceftazidime. Thus S-4661 possesses potent and well-balanced wide-spectrum antibacterial activity against various urological pathogens.

Anti-Bacterial Agents↗
PubMed2001

Effect of moderate exercise on immune senescence in men.

The purpose of this study was to examine the relationship between active compared to inactive lifestyles and immunocompetence in men. Subjects, all male volunteers, regularly exercising moderately were separated into three age groups: young (20-39 years), middle-aged (40-59 years) and elderly (more than 60 years). Age-matched sedentary male subjects served as controls in each group. Immunological assessments were, total leucocyte count, lymphocyte subpopulation counts, natural killer cell activity and neutrophilic phagocytosis. Total leucocyte and T-cell (CD3+) counts were not significantly different among the groups. Among T-cell subsets, there was a slight increase in helper T-cell (CD3+CD4+) and a decrease in cytotoxic/suppressor T-cell (CD3+CD8+) concentrations in the older sedentary subjects, resulting in an age-associated significant increase in the CD4:CD8 ratio among those control groups. However, among the exerciser groups, no such increase and decrease in the T-cell subpopulations or an age-related increase of the CD4:CD8 ratio were observed. Considering the components of innate immunity, the concentration of NK-cells (CD16+CD56+) significantly increased in the elderly exercisers, compared to that of the age-matched control subjects, or of the young group. The phagocytotic activity of neutrophils showed an age-associated decline, but of lesser degree in the elderly exercisers than in the elderly controls. Taken together, these results suggest that habitual and moderate training in later life is associated with a lesser age-related decline in certain aspects of circulating T-cell function and innate immunity.

Adult↗
PubMed1999

Reactivity of a dual amplified chlamydia immunoassay with different serovars of Chlamydia trachomatis.

A study was undertaken with different serovars (D, E, F, L2, MoPn) of Chlamydia trachomatis to determine the analytical sensitivity of a new dual amplified immunoassay (IDEIA PCE Chlamydia) for detecting chlamydial lipopolysaccharide. IDEIA PCE Chlamydia incorporates a polymer conjugate consisting of multiple copies of antibody and enzyme molecules to provide signal amplification. The test was also assessed with different protein A producing strains of Staphylococcus aureus in order to assess whether the use of a multiple antibody conjugate increased nonspecific binding. The detection limits varied for each serovar with a detection limit of 38 IFU/ml obtained with serovar F and 237 IFU/ml obtained with serovar D. The incorporation of the polymer conjugate resulted in a 2-5 fold increase in analytical sensitivity compared to an earlier version of the test using a conventional conjugate. No increase in cross reactivity with protein A producing strains of S. aureus was obtained. The new dual amplified test format offers potential as a sensitive low-cost screening assay for C. trachomatis infections.

Antigenic Variation↗
PubMed1998

[Basic evaluation of Chlamydia antigen detection by EIA using a dual amplification enhanced immunoassay method].

Chlamydia trachomatis is one of the important pathogens of STD in our country. Therefore, rapid accurate, reliable and convenient tests for its detection are required. So far, IDEIA Chlamydia has been employed as a useful diagnostic kit. Now, IDEIA PCE Chlamydia, applied as a dual amplification EIA method, has been developed. In our present studies, the sensitivity, reproducibility, cross reactivity, and reliability of IDEIA PCE Chlamydia were investigated and compared with those of IDEIA Chlamydia and LCR Chlamydia. The sensitivity of IDEIA PCE Chlamydia showed 2.4 x 10(2) IFU/ml for C. trachomatis D, 1.2 x 10(2) IFU/ml for C. trachomatis E, 3.8 x 10 IFU/ml for C. trachomatis F, and 1.25 x 10(2) IFU/ml for C. trachomatis L2. With regard to reproducibility, more than 2.4 x 10(2) IFU/ml of all strains of C. trachomatis and negative samples gave highly reproducible values. Though no cross reactivity was recognized among three strains of Staphylococcus aureus with concentrations of more than 10(9) IFU/ml, non-heated samples of over 10(6) CFU/ml showed cross reactivity. In our observations, phosphate, Mg2+, Ca2+, and Fe3+ inhibited the efficacy of both IDEIA and IDEIA PCE Chlamydia. Ca2+ per se could be an inhibitor in the case of urine samples analyzed by IDEIA and IDEIA PCE Chlamydia. These results indicate that IDEIA PCE Chlamydia kit for detection of C. trachomatis may be clinically useful because of its improved sensitivity over IDEIA Chlamydia and its invariable specificity and reliability.

Antigens, Bacterial↗
PubMed1998

The inhibitory effect of phosphate on the ligase chain reaction used for detecting Chlamydia trachomatis.

AIMS: To examine the detection limit of the ligase chain reaction kit for Chlamydia trachomatis, to study the inhibitory effect of phosphate on the ligase chain reaction, and to clarify the mechanism of inhibition. METHODS: Three reference serovars of C trachomatis--D/UW-3/Cx, F/UW-6/Cx, and L2/434/Bu--were used to test the sensitivity of the chlamydia ligase chain reaction. Comparison was made of the inhibition by phosphate before and after DNA amplification. Phosphate in up to 2.4 mM concentration was added to specimens of C trachomatis serovar D (1 to 50 inclusion forming units (IFU)/reaction) before DNA amplification to examine the concentration dependency of phosphate inhibition of the ligase chain reaction. RESULTS: The detection limits were 0.6 IFU/reaction for serovar D/UW-3/Cx and F/UW-6/Cx, and 0.4 IFU/reaction for L2/434/Bu. Phosphate inhibited the ligase chain reaction only when it was added before the amplification stage. The specimens containing chlamydia at 1 to 50 IFU/reaction were negative when the concentration of phosphate added at the prethermocycle stage was more than 1.2 mM. CONCLUSIONS: Ligase chain reaction analysis is a reliable method of diagnosing C trachomatis infection because of its high sensitivity. It would be clearly superior to the currently used methods if the problem of inhibitors could be eliminated. The mechanism of inhibition of the ligase chain reaction by phosphate was thought to be blockade of the amplification of the target DNA. The efficacy of the ligase chain reaction could be inhibited by phosphate in the urine, so duplicate dilution analysis of some negative specimens should be useful.

Chlamydia Infections↗
PubMed1997

Transgenic potato expressing a double-stranded RNA-specific ribonuclease is resistant to potato spindle tuber viroid.

We have produced transgenic potato lines expressing the yeast-derived double-stranded RNA-specific ribonuclease pac1. Five lines of pac1 potato (Solanum tuberosum L., cultivar Russet Burbank) challenged with potato spindle tuber viroid (PSTVd) suppressed PSTVd infection and accumulation. All of the progeny potato tubers produced by resistant plants were also free of PSTVd. Because the pac1 gene product digested PSTVd in vitro, double-stranded regions in PSTVd molecule and/or replicative intermediates may be targeted by pac1 gene product in the transgenic potato plant.

Endoribonucleases↗
PubMed1997

Tazobactam-piperacillin compared with sulbactam-ampicillin, clavulanic acid-ticarcillin, sulbactam-cefoperazone, and piperacillin for activity against beta-lactamase-producing bacteria isolated from patients with complicated urinary tract infections.

The antibacterial activity of tazobactam-piperacillin was compared with that of sulbactam-ampicillin, clavulanic acid-ticarcillin, sulbactam-cefoperazone and piperacillin against beta-lactamase-producing bacteria isolated from patients with complicated urinary tract infections. Tazobactam-piperacillin showed a broad antibacterial spectrum against gram-negative and gram-positive bacteria. The minimum inhibitory concentrations (MIC90) of tazobactam-piperacillin were 6.25 micrograms/ml against Escherichia coli, 1.56 micrograms/ml against Proteus mirabilis, 3.13 micrograms/ml against Proteus vulgaris, 6.25 micrograms/ml against methicillin-susceptible Staphylococcus aureus, and 6.25 micrograms/ml coagulase-negative methicillin-susceptible staphylococci. Against all beta-lactamase-producing bacteria tested the antibacterial activity of tazobactam-piperacillin was at least 4- to 64-fold stronger than that of piperacillin, clavulanic acid-ticarcillin, and sulbactam-ampicillin, and similar to or greater than that of sulbactam-cefoperazone except for E. coli.

Ampicillin↗
PubMed1995

Effects of sub-minimal inhibitory concentrations of antimicrobial agents on the cell surface of Klebsiella pneumoniae and phagocytic killing activity.

Changes in the phagocytic killing activity, capsule structure, and physicochemical properties such as the hydrophobicity and charge of the cell surface were studied in Klebsiella pneumoniae treated with sub-minimal inhibitory concentrations (MICs) of various antimicrobial agents. The phagocytic killing activity of macrophages was enhanced by penicillins, cephems, and monobactam in the absence of antibodies specific to the capsule or complement. No enhancement was observed with new quinolones, aminoglycosides, macrolide, or carbapenem. The thickness of the capsule structure was considerably reduced after the treatment with penicillins, cephems, and monobactam compared with the untreated control, and it was slightly reduced by new quinolones. No changes were observed in the capsule structure with aminoglycosides, macrolide, and carbapenem. The hydrophobicity on the cell surface of the bacteria was considerably increased after the treatment with penicillins, cephems, and monobactam compared with the control, slightly increased with new quinolones and carbapenem, and not changed with aminoglycosides and macrolide. The negative charge of the cell surface of the bacteria was reduced by penicillins, cephems, and monobactam compared with the control. It was slightly reduced by new quinolones and carbapenem but was not reduced by aminoglycosides and macrolide. These findings suggest that sub-MIC beta-lactam drugs such as penicillins, cephems, and monobactams cause thinning of the capsule of K. pneumoniae with increases in the hydrophobicity and decreases in the negative charge of the cell surface, which reduces the physical repulsion between the K. pneumoniae and phagocytes and enhances the sensitivity of the bacteria to phagocytic killing activity.

Anti-Bacterial Agents↗
PubMed1992

Differential effects of bacterial lipopolysaccharide and interferon-gamma on proliferation of two factor-dependent macrophage cell lines.

We examined the responsiveness of two factor-dependent macrophage cell lines, BDM-1 and its subclone, BDM-1W3, to bacterial lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) for their growth. LPS inhibited the M-CSF-dependent proliferation of BDM-1 cells but it had no effect on the proliferation of BDM-1W3 cells. LPS promoted DNA synthesis and supported the cell viability in the absence of CSFs in BDM-1 and BDM-1W3 cells, suggesting that the intracellular signals are transduced from the interaction of LPS with LPS-binding sites in BDM-1W3 cells as well as in BDM-1 cells. IFN-gamma inhibited the proliferation of BDM-1 and BDM-1W3 cells. However, BDM-1 cells were more susceptible to the inhibitory effect of IFN-gamma than BDM-1W3 cells. In contrast to LPS and IFN-gamma, TNF-alpha did not inhibit the proliferation of BDM-1 and BDM-1W3 cells. These cell lines should be useful for studying the regulatory mechanisms in CSF-dependent macrophage proliferation.

Animals↗
PubMed1991

Opposite effects of bacterial lipopolysaccharide on Fc-receptor-mediated phagocytosis of two bone marrow-derived macrophage cell lines, BDM-1 and BDM-1W3.

We have reported the isolation and characterization of three factor-dependent macrophage cell lines from bone marrow cells of C3H/HeN mice. We have since isolated a subclone, BDM-1W3, from one of these cell lines. We found previously that BDM-1W3 has a different sensitivity to bacterial lipopolysaccharide (LPS) for growth than its parental cell line, BDM-1. In this report, we show that LPS inhibits BDM-1W3 phagocytosis of antibody-coated sheep erythrocytes (Fc-mediated phagocytosis), whereas it enhanced Fc-mediated phagocytosis by BDM-1. It was observed that a loss of Fc-receptor capacity parallels a loss of phagocytic activity in LPS-treated BDM-1W3 cells. LPS stimulated phagocytosis of latex beads by BDM-1 and BDM-1W3, suggesting that Fc-mediated phagocytosis and phagocytosis of latex beads differ in their regulatory mechanisms. When BDM-1 cells were cultured with LPS, they underwent drastic morphological changes, whereas LPS-treated BDM-1W3 cells did not change significantly. Gamma interferon enhanced FC-mediated phagocytosis by BDM-1, while it has no significant effect on that by BDM-1W3. These cell lines should be useful for studying signal transduction mechanisms in LPS-mediated macrophage activation.

Antigens, Surface↗
PubMed1991

Constitutive production of granulocyte colony-stimulating factor by hybrids of a SV40-transformed mouse macrophage and a renal adenocarcinoma cell line.

Mouse macrophage BAM3 cells produced colony-stimulating factors (CSFs) after stimulation with bacterial lipopolysaccharide (LPS). By assaying the CSF using various interleukin 3-dependent cell lines, it was shown that most of the CSFs produced by BAM3 cells were granulocyte CSF (G-CSF). The granulocyte-macrophage CSF (GM-CSF) gene was also expressed in BAM3 cells after stimulation with LPS. When BAM3 cells were fused with the mouse renal adenocarcinoma cell line RAG which does not produce G-CSF, two of four hybrid cell lines constitutively produced large quantities of G-CSF. About 300 bp of the promoter region of mouse G-CSF chromosomal gene was inserted upstream of the Escherichia coli chloramphenicol acetyltransferase gene, and introduced into BAM3, RAG and hybrid cells. The G-CSF promoter was activated by stimulation with LPS, in BAM3 cells, but was inert in RAG cells. On the other hand, there was significant constitutive CAT activity in the hybrid cells.

Adenocarcinoma↗
PubMed1988

Establishment and characterization of factor-dependent macrophage cell lines.

Three macrophage cell lines from bone marrow cells of C3H/HeN mice were isolated by successive transfer of the cells in culture with L-cell-conditioned medium (LCM) or WEHI-3 cell-conditioned medium (WEHI-3CM). These cell lines, which express Fc receptors, are involved in Fc-mediated phagocytosis and possess nonspecific esterase activity. Two (BDM-1 and BDM-2) of three cell lines show dependency for growth on either macrophage colony-stimulating factor (M-CSF) (CSF-1) or granulocyte-macrophage colony-stimulating factor (GM-CSF) and do not respond to interleukin 3 (IL-3). The third clone (BDM-3) proliferates in response to IL-3 as well as to GM-CSF and weakly responds to M-CSF and to interleukin 4 (IL-4). GM-CSF, in combination with the suboptimal concentration of M-CSF, acted synergistically on the proliferation of BDM-1 cells. The tumor-promoting phorbol diester, 12-o-tetradecanoyl-phorbol-13-acetate (TPA) also acted synergistically with the three CSFs (IL-3, GM-CSF, and M-CSF) to stimulate the proliferation of BDM-1 cells. The synergistic effect was observed when cells were pretreated with TPA and subsequently stimulated with IL-3. The calcium ionophore A23187 enhanced the proliferation of BDM-1 cells costimulated with TPA and IL-3. These factor-dependent macrophage cell lines should be useful for studying signal transduction mechanisms in the regulation of cell growth.

Animals↗