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Biomedical subjects

Satoshi Ichiyama

Publications and source records attributed to Satoshi Ichiyama.

At least 37 records · Page 2Linked to original sources
PubMed2004

Whole-blood counting immunoassay as a short-turnaround test for detection of hepatitis B surface antigen, anti-hepatitis C virus antibodies, and anti-Treponema pallidum antibodies.

Whole-blood samples were used for a counting immunoassay (CIA) with the aim of developing a short- turnaround test. After optimization of the CIA, hepatitis B surface antigen (HBsAg), anti-hepatitis C virus antibodies (anti-HCV), and anti-Treponema pallidum antibodies (anti-TP) were detected as efficiently as by an enzyme immunoassay (EIA) with serum samples. The correlations between whole-blood CIA and serum EIA were 99.8, 97.1, and 99.4% for HBsAg, anti-HCV, and anti-TP, respectively. Whole-blood CIA may be of value when rapid screening of many samples is required.

Antibodies, Bacterial↗
PubMed2004

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2002].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 899 strains of Gram-positive bacteria, 1500 strains of Gram-negative bacteria, and 158 strains of anaerobic bacteria obtained from 28 medical institutions during 2002 was measured. The results were as follows; 1. MEPM was more active than other carbapenem antibiotics against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae. MIC90 of MEPM against Pseudomonas aeruginosa was the lowest of the drugs tested. MEPM showed low cross-resistant rate against both imipenem-resistant P. aeruginosa and ciprofloxacin-resistant P. aeruginosa. MEPM was active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE). 2. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 3.1% (4 strains) in Escherichia coli and 1.9% (2 strains) in Klebsiella pneumoniae. Carbapenems including MEPM were active against these ESBL strains. In conclusion, the results from this surveillance study suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem; at present, 7 years after available for commercial use.

Bacteria↗
PubMed2003

National surveillance of species distribution in blood isolates of Candida species in Japan and their susceptibility to six antifungal agents including voriconazole and micafungin.

OBJECTIVES: The aim of this study was to evaluate species distribution and antifungal susceptibility of Candida blood isolates in Japan. METHODS: In a 1 year surveillance programme, 535 Candida blood isolates were collected. Identification of species was followed by examination with the broth microdilution method, as described in NCCLS M27-A2, of antifungal susceptibility to six agents, including voriconazole and micafungin, with readings after 24 and 48 h of incubation. RESULTS: The overall species distribution was: 41% Candida albicans, 23% Candida parapsilosis, 18% Candida glabrata, 12% Candida tropicalis and 2% Candida krusei. The concentrations of fluconazole necessary to inhibit 90% of the isolates (MIC(90)) at 24/48 h were 0.25/1 mg/L for C. albicans, 0.5/2 mg/L for C. parapsilosis, 4/32 mg/L for C. glabrata and 4/>128 mg/L for C. tropicalis. Percentages of fluconazole resistance were 1.8% for C. albicans, 0.8% for C. parapsilosis, 5.2% for C. glabrata and 3.2% for C. tropicalis, taking the tendency of trailing growth of C. tropicalis into account. MIC(90) of voriconazole was 0.5 mg/L, although 35% of isolates less susceptible (>/=16 mg/L) to fluconazole showed resistance (>/=2 mg/L). Micafungin was very active against all species (MIC(90), 0.03 mg/L) except for C. parapsilosis (MIC(90), 2 mg/L). CONCLUSIONS: These data suggest that, in Japan, the species distribution of Candida bloodstream infections and the fluconazole resistance rate are similar to those reported previously in North America and Europe. Voriconazole and micafungin appear to have strong in vitro activity against Candida blood isolates, although continuing surveillance and further clinical research are needed.

Amphotericin B↗
PubMed2003

Effects of the tyrosine kinase inhibitor imatinib mesylate on a Bcr-Abl-positive cell line: suppression of autonomous cell growth but no effect on decreased adhesive property and morphological changes.

Expression of the Bcr-Abl oncoprotein alters various aspects of hematopoietic cells. We investigated the effects of a Bcr-Abl tyrosine kinase inhibitor, imatinib mesylate, on the proliferation, adhesive properties, and morphology of a Bcr-Abl-transferred cell line, TF-1 Bcr-Abl, in comparison with parental TF-1. First, the factor-independent growth of TF-1 Bcr-Abl was inhibited in the presence of imatinib mesylate, but this inhibition was overcome by addition of exogenous granulocyte-macrophage colony-stimulating factor. Imatinib mesylate remarkably reduced tyrosine phosphorylation of Bcr-Abl, Cbl, and Crkl in a time-dependent manner, and their complex formation also was affected. Imatinib mesylate inhibited activation of Stat5 rather than the MEK-ERK1/2 pathway. TF-1 Bcr-Abl cells exhibited a round shape, unlike TF-1, and the adhesive property to fibronectin was much lower than that of TF-1. Although the Bcr-Abl oncoprotein may be involved negatively in cell adhesion, the decreased adhesion and altered morphology of TF-1 Bcr-Abl cells were minimally affected by imatinib mesylate and seemed independent of Bcr-Abl kinase activity. The present data indicated that the Bcr-Abl-specific kinase inhibitor cannot control Bcr-Abl-induced cell alterations other than autonomous growth.

Benzamides↗
PubMed2003

Effect of Porphyromonas gingivalis vesicles on coaggregation of Staphylococcus aureus to oral microorganisms.

Vesicles from the outer membrane of Porphyromonas gingivalis have the ability to aggregate a wide range of Streptococcus spp., Fusobacterium nucleatum, Actinomyces naeslundii, and Actinomyces viscosus. We found that in the presence of P. gingivalis vesicles, Staphylococcus aureus coaggregated with Streptococcus spp., and the mycelium-type Candida albicans, but not the yeast type. Autoaggregation of S. aureus in the presence of P. gingivalis vesicles is inhibited by L-arginine, L-lysine, and L-cysteine. Both the methicillin-sensitive (MSSA) and -resistant (MRSA) strains of S. aureus were able to coaggregate with Streptococcus spp., A. naeslundii, and A. viscosus when they were treated with P. gingivalis vesicles. P. gingivalis vesicle-treated mycelium-type C. albicans coaggregated with S. aureus, but the yeast-type did not. These results indicate that strains of S. aureus, including MRSA, could adhere to oral biofilms in dental plaque on the tooth surface or in the gingival crevice when P. gingivalis is present.

Actinomyces↗
PubMed2003

Detection of bacteria and fungi in BacT/Alert standard blood-culture bottles.

Incubation periods of aerobic (AE) and anaerobic (AN) blood-culture bottles with the BacT/Alert system were assessed in our laboratory. We reviewed the results of 6229 blood-culture sets collected at Kyoto University Hospital from January 1999 to December 2000. Of these sets, 731 (11.7%) were positive for bacteria or yeast. Excluding 87 sets with growth evidence on arrival, of the 644 positive blood-culture sets from 341 patients, a total of 691 organisms were isolated. Of the 691 organisms, 413 (59.8%) were recovered from both bottles, 206 (29.8%) were recovered only from the AE bottle, and 72 (10.4%) were recovered only from the AN bottle. The AE bottle was significantly superior to the AN bottle in terms of both recovery rate and detection time for overall organisms, but there was no significant difference in detection time for facultative anaerobic bacteria between the two bottles. Of the 691 organisms, 530 (76.7%) were classified as usual pathogens. Of the 530 usual pathogens, 501 (94.5%) were recovered in at least one bottle of each set within the first 3 days, and 523 (98.7%) within the first 5 days of incubation. Twenty-nine organisms initially isolated on day 4 or later were recovered from 19 patients. Of these, chart reviews indicated that 21 organisms recovered from 11 patients were considered clinically significant bacteria, and the reviews also revealed that no patient had a treatment plan altered based on the results of positive blood culture. Seven organisms initially isolated on day 6 or later were recovered from 7 patients. Chart reviews revealed that 5 of these organisms from 5 patients were considered to be clinically significant. In conclusion, if the incubation period had been less than 3 days, 11 patients with clinically significant bacteremia or fungemia, (3.2% of all patients with bacteremia or fungemia) would have been undiagnosed. Similarly, with an incubation period of 5 days, 5 such patients (1.5%) would have been undiagnosed.

Bacteria, Aerobic↗
PubMed2003

Biliary bacteria in living related liver transplant recipients: microbiology and rapid detection system using flow cytometry.

Since cholangitis is a major complication in living related liver transplant (LRLT) recipients, rapid detection of biliary bacteria is necessary for the management of patients. We have developed a screening method for the detection of biliary bacteria using flow cytometry (FCM). Two hundred and seventy eight bile samples were obtained from 50 patients with biliary drainage tubes after LRLT at Kyoto University Hospital between July and September 2001. Of the 278 samples, 165 (59.3%) were culture-positive. The most common isolates were Enterococcus species, Pseudomonas species, Staphylococcus species, Klebsiella species, and Candida species. As the original FCM system was inadequate for specifically detecting bacteria in bile samples, we established the most appropriate gate and cut-off value from the particle distribution represented on scattergram of the forward-scattered light and fluorescent light intensity. The 3% cut-off value was most preferably related to the culture results. The FCM system detected biliary bacteria with a sensitivity of 93.9%, specificity of 81.4%, positive predictive value of 88.1%, negative predictive value of 90.2%, false-positive rate of 7.6%, false-negative rate of 3.6%, and percent agreement of 88.9% between FCM and culture. Therefore, FCM can be a useful method in clinical laboratories for the rapid screening for biliary bacteria in LRLT recipients.

Adolescent↗
PubMed2003

Anaerobic bacteremia: the yield of positive anaerobic blood cultures: patient characteristics and potential risk factors.

The anaerobic blood culture (AN) bottle is routinely used in Japan with little discussion as to its justification or validity. We retrospectively studied the AN bottle yield of obligate anaerobes and the characteristics of, and potential risk factors in, patients with anaerobic bacteremia during a 2-year period (1999-2000) at four university hospitals and one community hospital. Thirty-four of 18,310 aerobic and anaerobic blood culture sets from 6,215 patients taken at the university hospitals, and 35 of 2,464 samples taken from 838 patients at the community hospital, yielded obligate anaerobes. Bacteroides species and Clostridium species accounted for 60% of the isolates. Fifty-seven patients from 69 blood culture sets containing anaerobes had clinically significant anaerobic bacteremia. Among these 57 patients, 24 (49%) were oncology patients, 40 (70%) had an obvious source of anaerobic infection, 15 (26%) had recent surgery and/or were in an immunosuppressed state. We concluded that the recovery rate of obligate anaerobes isolated from AN bottles was low, and the patients with anaerobic bacteremia had limited number of underlying diseases or potential risk factors for anaerobic infections. Therefore, anaerobic blood cultures may be selectively used according to the potential risk for anaerobic infections.

Adolescent↗
PubMed2003

Automated analysis of differentiation-induced leukemic cells during all-trans retinoic Acid therapy of acute promyelocytic leukemia.

During differentiation-induction therapy of acute promyelocytic leukemia (APL) patients with all-trans retinoic acid (ATRA), a variety of APL-derived bizarre granulocytic cells appear in the peripheral blood. To evaluate the differentiation induction of leukemic cells, we have developed a new scattergram analyzing program with an automated hematology analyzer and compared the data with the flow cytometry measuring the expression of differentiation-associated cell surface antigens, CD11b and CD16. We used the fluorescence intensity and side scatter as parameters of granulocytic maturation in the analysis with the automated hematology analyzer. The analysis of 2 ATRA-treated APL patients and in vitro study using HL-60 cells demonstrated that the levels of fluorescence intensity and side scatter decreased as accompanied with granulocytic maturation, and these changes were parallel with the results of flow cytometry. Our automated scattergram analysis of cell differentiation will contribute to general, objective, and real-time evaluation of differentiation-induction therapy of APL with ATRA.

Adult↗
PubMed2003

[Activities of antimicrobial agents against 8,474 clinical isolates obtained from 37 medical institutions during 2000 in Japan].

A survey was conducted to determine the antimicrobial activity of fluoroquinolones and other antimicrobial agents against 8,474 clinical isolates obtained from 37 Japanese medical institutions in 2000. A total of 25 antimicrobial agents were used, comprising 4 fluoroquinolones, 13 beta-lactams, minocycline, chloramphenicol, clarithromycin, azithromycin, gentamicin, amikacin, sulfamethoxazole-trimethoprim, and vancomycin. A high resistance rate of over 85% against fluoroquinolones was exhibited by methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium. Isolates showing resistance to fluoroquinolones among methicillin-resistant coagulase-negative Staphylococci, Enterococcus faecalis, and Pseudomonas aeruginosa from UTI accounted for 30-60%. However, many of the common pathogens were still susceptible to fluoroquinolones, such as Streptococcus pneumoniae (including penicillin-resistant isolates), Streptococcus pyogenes, methicillin-susceptible S. aureus (MSSA), methicillin-susceptible coagulase-negative Staphylococci, Moraxella catarrhalis, the Enterobacteriaceae family, and Haemophilus influenzae (including ampicillin-resistant isolates). About 85% of P. aeruginosa isolated from RTI were susceptible to fluoroquinolones. In conclusion, this survey of sensitivity to antimicrobial agents clearly indicated trend for increasing resistance to fluoroquinolones among MRSA, Enterococci, and P. aeruginosa isolated from UTI, although fluoroquinolones are still effective against other organisms and P. aeruginosa from RTI as has been demonstrated in previous studies.

Anti-Bacterial Agents↗
PubMed2003

[Nationwide sensitivity surveillance of ciprofloxacin and various parenteral antibiotics against bacteria isolated from patients with severe infections--the first Ciproxan IV special investigation in 2001].

The parenteral injection of ciprofloxacin (CPFX), a fluoroquinolone antimicrobial drug, was approved in September 2000 and a re-examination period of 6 years was set at that time. As a special investigation to apply for re-examination of this drug, it has been planned to conduct 3 nationwide surveillances during the re-examination period by collecting clinically isolated bacteria from patients with severe infections, to whom the drug was mainly indicated, and examining drug susceptibilities of the bacteria to various parenteral antimicrobial drugs including CPFX. This time, we determined the minimum inhibitory concentrations (MICs) of various parenteral antimicrobial drugs including CPFX against 1,220 strains isolated from patients with severe infections by the micro-liquid dilution method and compared susceptibilities of various clinically isolated bacteria to CPFX with those to other antimicrobial drugs. Gram-positive bacteria were less susceptible to CPFX than to carbapenems except 2 bacterial species, Enterococcus faecium and Enterococcus avium but susceptibilities of methicillin-susceptible Staphylococcus aureus (MSSA), Staphylococcus epidermidis and Enterococcus faecalis to CPFX were comparable to those to cefozopran. Susceptibility of Streptococcus pneumoniae to CPFX did not differ among ampicillin (ABPC)-susceptible Streptococcus pneumoniae (MIC of ABPC: < 0.25 microgram/ml), ABPC-intermediate S. pneumoniae (MIC of ABPC: 0.25-2 micrograms/ml) and ABPC-resistant S. pneumoniae (MIC of ABPC: > or = 4 micrograms/ml) MIC90 of CPFX: 1 microgram/ml) and a decrease in the antimicrobial activity seen among cephem and carbapenem antimicrobial drugs against penicillin-intermediate strains was not noted with CPFX. Gram-negative bacteria were susceptible to CPFX similarly to carbapenems and the MIC90 values of CPFX were in the range from < or = 0.063 to 2 micrograms/ml against strains except Stenotrophomonas maltophilia and Burkholderia cepacia. Pseudomonas aeruginosa was most susceptible to CPFX among the antibacterial drugs examined and the MIC90 was 2 micrograms/ml. CPFX also showed the lowest MIC90 value (0.5 microgram/ml) against beta-lactam-resistant P. aeruginosa among the drugs examined. When extended-spectrum beta-lactamase (ESBL) production and class B beta-lactamase production were examined in 439 strains of Enterobacteriaceae and 168 strains of glucose non-fermentative bacteria out of the Gram-negative bacteria collected this time, 3 strains (0.49%) producing ESBL and 7 strains (1.15%) producing class B beta-lactamase were found. The MIC range of CPFX to these 10 strains was between < or = 0.063 to 8 micrograms/ml and 5 strains among those showed susceptibilities (MIC of CPFX: 1 microgram/ml) based on the NCCLS breakpoint. CPFX also showed a satisfactory result concerning susceptibilities of major causal bacteria based on the report of the committee of Japan Society of Chemotherapy on the standard method for determination of susceptibility to antimicrobial agents, the breakpoint of pneumonia. Furthermore, susceptibilities of various bacteria isolated clinically from patients with severe infections this time did not differ much from the result of the nationwide surveillance which we conducted in 1997. Thus, it was concluded that the antimicrobial activity of CPFX was maintained in the post-marketing surveillance for its parenteral preparation.

Adolescent↗
PubMed2002

Sustained activation of MEK1-ERK1/2 pathway in membrane skeleton occurs dependently on cell adhesion in megakaryocytic differentiation.

A human megakaryoblastic cell line, CMK, was treated with 12-o-tetradecanoylphorbol-13-acetate (TPA) for differentiation-induction. We examined TPA-induced activation of the MEK1-ERK1/2 pathway in the 100,000g Triton X-insoluble fraction of CMK cells as the membrane skeleton and researched the relation of the MEK1-ERK1/2 activation with integrin expression. We found that this activation was divided into two phases: the first activation occurred transiently in the membrane skeleton fraction of the suspended cell status and diminished after 1h; and the second sustained activation was maintained by cell adhesion. TPA-treated CMK cells revealed increased expression of integrins alphaIIb and beta3 only when the cell adhesion persisted, regardless of the difference of culture substratum. Sustained activation of the MEK1-ERK1/2 pathway is generated in the membrane skeleton by continuous cell adhesion and seems to be essential to TPA-induced megakaryocytic differentiation of CMK cells.

Butadienes↗
PubMed2002

Thyroid specific T helper cell analysis by ELISPOT assay with thyrotropin receptor (TSH-R) peptides.

We previously reported that a synthetic peptide induced humoral autoimmunity to thyrotropin receptor (TSH-R) and the expansion of antigen-specific type 2 helper T (Th2) cell population in mice. The peptide corresponds to the human TSH-R C-terminal region. In the present study, we undertook a similar approach in patients with Graves' disease (GD). Peripheral lymphocytes from 5 healthy controls and 11 GD patients were prepared and analyzed for cytokines from helper T cells by an antigen specific enzyme-linked immuno spot (ELISPOT) assay. In GD patients, the total number of IL-4 producing cells increased significantly and the number of interferon-gamma(IFN-gamma) producing cells decreased. Further, co-incubation with several of the 20 kinds of TSH-R extracellular peptides increased the number of IL-4 producing cells in patients with GD. Such stimulatory peptides appear frequently in a TSH-R sequence. These peptides did not affect the numbers of IFN-gamma producing cells significantly. These results indicated that GD patients have an expanded Th2 population responding to TSH-R and the dominance of the humoral immune system in such patients.

Antigens↗
PubMed2002

Induction of gamma interferon and nitric oxide by truncated pneumolysin that lacks pore-forming activity.

Pneumolysin (PLY), an important virulence factor of Streptococcus pneumoniae, is known to exert various effects on the host immune cells, including cytokine induction, in addition to its known cytolytic activity as a member of the thiol-activated cytolysins. It is of interest to determine whether cytolytic activity is involved in triggering the cytokine production. In this study, we constructed full-length recombinant PLY and noncytolytic truncated PLYs with C-terminal deletions to examine the response of spleen cells to these PLY preparations. When cytolytic activity was blocked by treatment with cholesterol, full-length PLY was capable of inducing gamma interferon (IFN-gamma) production. Truncated PLYs that originally exhibited no cytolytic activity were also active in IFN-gamma induction. Therefore, the IFN-gamma-inducing ability of PLY appeared to be independent of the cytolytic activity. Furthermore, IFN-gamma-inducing preparations were also capable of inducing nitric oxide synthase expression and nitric oxide (NO) production, and the addition of neutralizing antibody to IFN-gamma abolished the NO production. These results clearly demonstrated that PLY is capable of inducing IFN-gamma production in spleen cells by a mechanism different from pore formation and that the induced IFN-gamma stimulates NO production. These findings were discussed with reference to the contribution of PLY to the virulence of S. pneumoniae in vivo.

Animals↗
PubMed2002

Immature granulocyte count after liver transplantation.

We evaluated the significance of immature granulocyte (IG) count during the clinical course after liver transplantation. We counted IG using the flow cytometric method with CD16, CD11b, and CD45 antibodies. Samples were obtained from 31 patients in the Department of Transplantation and Immunology, and we determined (i) the distribution of IG peak value, (ii) the distribution of IG peak time-points, (iii) the clinical background of patients with high IG, and (iv) the clinical course of high IG cases. We observed the appearance of IG (100/microl or higher) in the majority of the patients (23 out of 31 patients; 74.2%). The IG peak was detected on the 19th day after transplantation. We observed serious complications, such as melena, rejection, or severe infection, in high IG (500/microl or higher) cases. We observed instances of inflammation with low C-reactive protein (CRP) value in the presence of IG. We believe that IG is a useful marker to monitor inflammation.

Biomarkers↗
PubMed2002

Evaluation of a commercially available serologic assay for antibodies against tuberculosis-associated glycolipid antigen.

A commercially available enzyme immunoassay developed to detect antibodies to a tuberculosis-associated glycolipid antigen was evaluated for serologic diagnosis of tuberculosis. This was a multicenter study comparing the assay with other methods in 78 patients with active pulmonary tuberculosis and in 54 controls with non-tuberculous lung diseases. Sensitivities were highest for sputum culture (91.0%), followed by immunoassay (79.5%), nucleic acid amplification (77.3%), and finally acid-fast staining of sputum smear (60.3%). Immunoassay and amplification, both rapid methods, had similarly high sensitivity in smear-positive subjects (89.4 and 88.9%, respectively); in smear-negative subjects these two techniques showed low sensitivity (64.5 and 60.0%, respectively). Concordance between the two methods was relatively low (72.0%). With regard to specificity, seven out of ten patients with old tuberculosis had positive result by immunoassay (30% specificity). In the control group, 10 out of 54 patients had positive immunoassay result (72.2% specificity), with notably limited specificity in the elderly. The tuberculous glycolipid assay is a rapid method sufficiently sensitive for detection of tuberculosis infection, even in smear-negative patients.

Adolescent↗
PubMed2002

[Advances of laboratory testing for the rapid diagnosis of tuberculosis].

Rapid diagnosis and treatment are extensively important for preventing transmission of Mycobacterium tuberculosis: In 1994, The Centers for Disease Control and Prevention, CDC, has published recommendations for the rapid diagnosis in the laboratories, in which smear result should be reported within 24 h, detection and identification within 10 to 14 days, and susceptibility within 15 to 30 days. New technologies, therefore, should be implemented in the laboratory. There have been significant advances in the practice of microbiology. Nucleic acid amplification, rapid culture system, antigen detection, and ATP assay system have provided new approaches to the rapid diagnosis of tuberculosis. In the present paper, we review studies which evaluated the reliability, rapidity, and requisite diagnostic capability for each method. Furthermore, we propose an appropriate test algorithm in the clinical laboratories.

Clinical Laboratory Techniques↗