Biomedical subjects

Y Hirakata

Publications and source records attributed to Y Hirakata.

At least 37 records · Page 2Linked to original sources

PubMed2000

Toxic shock-like syndrome caused by T serotype B3264 streptococcus.

A 45-year-old woman was transferred from a local hospital to our hospital because of shock-like manifestations in addition to septic polyarthritis and necrotizing cellulitis of the left leg. Since Streptococcus pyogenes was isolated from the blood culture examined one day before admission, the diagnosis of streptococcal toxic shock-like syndrome (TSLS) was made. Antibiotic treatment together with supportive care started at the time of admission, resulting in clinical improvement, although poststreptococcal acute glomerulonephritis occurred during the period. TSLS is a life-threatening disease, but early recognition of the disease and prompt initiation of appropriate treatment may lead to successful outcome.

Anti-Bacterial Agents↗

PubMed1999

Paradoxical synergistic effects of tumour necrosis factor and interleukin 1 in murine gut-derived sepsis with Pseudomonas aeruginosa.

The authors evaluated the synergistic effect of tumour necrosis factor (TNF) and interleukin 1 (IL-1) in gut-derived sepsis in mice. After colonization of Pseudomonas aeruginosa strain D4 in the gastrointestinal tract, cyclophosphamide was administered to induce bacterial translocation of the P. aeruginosa and thereby to cause gut-derived sepsis. In this model, treatment either with 8 microg/kg of recombinant human TNF-alpha (rhTNF-alpha) or 2 microg/kg of recombinant human interleukin 1alpha (rhIL-1alpha) solely did not affect the mortality, whereas combined administration of the same doses of rhTNF-alpha and rhIL-1alpha significantly increased the mortality rate in comparison with saline-treated mice. Bacterial counts in liver and blood were significantly higher in rhTNF-alpha and rhIL-1alpha treated mice than in saline-treated mice. Endogenous TNF-alpha and IL-1beta productions were stimulated after combined treatment with rhTNF-alpha and rhIL-1alpha. On the contrary to these adverse effects, combined treatment with 500 microg/kg of rhTNF-alpha and 50 microg/kg of rhIL-1alpha on the day before the administration of cyclophosphamide significantly reduced the mortality from septic infection. We conclude that TNF and IL-1 synergistically affect the mortality of mice after gut-derived sepsis due to P. aeruginosa in mice and the timing of treatment with these cytokines causes both extremes in their effects.

Animals↗

PubMed1999

Qualitative and quantitative characterization of Fas (APO-1/CD95) on leukemic cells derived from patients with B-cell neoplasms.

Expression density and function of Fas (APO-1/CD95) on malignant B-cells, an antigen thought responsible for abnormal tumor biology, remains to be fully understood. Fifty-five cases with B-cell neoplasms of acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), hairy cell leukemia (HCL), B-cell malignant lymphoma (ML), and myeloma (MM) were studied for qualitative and quantitative expression and function of Fas using flow cytometry and annexin-V staining methods. Fas expression was flow cytometrically unimodal with heterogeneous density and showed quantitatively characteristic features among different diseases; weak in ALL, faint in CLL, moderate in HCL, and strong in ML, respectively. Not only full-length but also alternatively spliced truncated mRNAs were detected even in leukemic B-cells with qualitatively faint or negative Fas, and then band density of the former transcripts by RT-PCR was correlated to the Fas protein expression level. Short-term culture of freshly isolated cells gave rise to increases of Fas density and susceptibility for apoptosis, suggesting that the mRNA and inducible Fas are functional at least in vitro. These results show that Fas is a biological marker for characterizing B-cell neoplasms reflecting various stages of B-cell ontogeny and may have clinical utility as a therapeutic strategy.

Apoptosis↗

PubMed1999

Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study.

Antimicrobial susceptibility of 996 isolates of Streptococcus pneumoniae from clinical specimens was investigated in 11 Asian countries from September 1996 to June 1997. Korea had the greatest frequency of nonsusceptible strains to penicillin with 79.7%, followed by Japan (65.3%), Vietnam (60.8%), Thailand (57.9%), Sri Lanka (41.2%), Taiwan (38.7%), Singapore (23.1%), Indonesia (21.0%), China (9.8%), Malaysia (9.0%), and India (3.8%). Serotypes 23F and 19F were the most common. Pulsed-field gel electrophoresis (PFGE) of 154 isolates from Asian countries showed several major PFGE patterns. The serotype 23F Spanish clone shared the same PFGE pattern with strains from Korea, Japan, Singapore, Taiwan, Thailand, and Malaysia. Fingerprinting analysis of pbp1a, pbp2x, and pbp2b genes of 12 strains from six countries also showed identical fingerprints of penicillin-binding protein genes in most strains. These data suggest the possible introduction and spread of international epidemic clones into Asian countries and the increasing problems of pneumococcal drug resistance in Asian countries for the first time.

Aminoacyltransferases↗

PubMed1999

Relationship between genetic alteration of the rpsL gene and streptomycin susceptibility of Mycobacterium tuberculosis in Japan.

We have investigated the effect of genetic alterations in the rpsL gene on the MICs of streptomycin for Mycobacterium tuberculosis strains. Direct DNA sequencing showed a point mutation in 23/121 strains; in 18 strains the mutation was associated with an amino acid change. The MICs of streptomycin in 22 out of 23 point-mutated strains were > or = 256 mg/L. Restriction fragment length polymorphism (RFLP) analysis showed mutations at codon 43 in all 18 strains with point mutations in the same codon. Our results suggest that both RFLP and base sequencing analysis of the rpsL gene are useful for the rapid prediction of highly streptomycin-resistant strains of M. tuberculosis.

Deoxyribonucleases, Type II Site-Specific↗

PubMed1999

Fosfomycin alters lipopolysaccharide-induced inflammatory cytokine production in mice.

To determine the mechanisms of immunomodulating action of fosfomycin (FOF), we examined its effect on the production of inflammatory cytokines in mice injected with lipopolysaccharide (LPS). Treatment with FOF significantly lowered the peak serum levels of tumor necrosis factor alpha and interleukin-1 beta, indicating that FOF alters inflammatory cytokine production after LPS stimulation.

Animals↗

PubMed1999

Effect of antiflagellar human monoclonal antibody on gut-derived Pseudomonas aeruginosa sepsis in mice.

We evaluated the effect of antiflagellar human monoclonal antibody on gut-derived Pseudomonas aeruginosa sepsis. Mice were given a suspension of P. aeruginosa SP10052 in their drinking water and were simultaneously treated with ampicillin (200 mg/kg of body weight) to disrupt the normal bacterial flora. Cyclophosphamide was then administered to induce leukopenia and translocation of the P. aeruginosa that had colonized the gastrointestinal tract, thereby producing gut-derived generalized sepsis. In this model, intraperitoneal injection of 100 microg of antiflagellar human monoclonal antibody (SC-1225) per mouse for 5 consecutive days significantly (P < 0.01) increased the survival rate compared with that for mice treated with bovine serum albumin (BSA). Treatment with SC-1225 significantly reduced the average number of viable bacteria in portal blood, liver, and heart blood compared with the average number after treatment with BSA. Furthermore, the presence in serum of the inflammatory cytokines tumor necrosis factor alpha and interleukin 6 were evaluated as markers of severity of infection, and the results showed that the levels of these cytokines in mice treated with SC-1225 were significantly decreased in comparison with those in BSA-treated control mice. Although there was no significant difference in the number of bacteria that colonized the intestine, SC-1225 treatment significantly increased bacterial opsonophagocytosis by cultured peritoneal macrophages from mice with or without cyclophosphamide pretreatment. Our results indicate that antiflagellar human monoclonal antibody SC-1225 protects mice against gut-derived sepsis caused by P. aeruginosa and suggest that such an effect is due to its opsonophagocytic activity and the reduced motility of the translocated bacteria once the bacteria move from the intestine into the bloodstream.

Animals↗

PubMed1999

Comparison between PCR and detection of antigen in sera for diagnosis of pulmonary aspergillosis.

We evaluated the usefulness of PCR and antigen detection for the diagnosis of pulmonary aspergillosis. Forty-four serum samples from patients with pulmonary aspergillosis (33 with pulmonary aspergilloma, 4 with allergic bronchopulmonary aspergillosis, 4 with invasive pulmonary aspergillosis, and 3 with aspergillus pyothorax) were used in this study. PCR detection of Aspergillus DNA in serum samples was successful in 39 patients. Galactomannan antigen was detected by sandwich enzyme-linked immunosorbent assay in 25 patients and by latex agglutination test in 13 patients. Detection of Aspergillus DNA in serum samples by nested PCR had the highest sensitivity of the three methods tested for the diagnosis of pulmonary aspergillosis.

Antigens, Fungal↗

PubMed1999

Clonal analysis of B-cell leukemias and lymphomas using the polymerase chain reaction for the third complementarity determining region of the IgH gene: a study of 75 cases from Nagasaki Japan.

Using semi-nested polymerase chain reaction (PCR), we examined 75 Japanese cases of hematologic malignancies with B-cell antigens including 25 common acute lymphoblastic leukemia (ALL), 13 chronic lymphocytic leukemia (CLL), 28 B-cell malignant lymphoma (B-ML), 2 hairy cell leukemia (HCL), 7 acute myelogenous leukemia with B-cell antigens (AML-B), and 23 controls. When amplified products were analysed by a standard polyacrylamide gel electrophoresis, the sensitivity for detection of clonal IgH rearrangements in each group of ALL, CLL, B-ML, HCL, and AML-B was 88%, 92.3%, 71.4%, 100%, and 57.1%, respectively, with an overall sensitivity of 80.0%. There were no false positive results in any of the control samples. Single strand conformation polymorphism (SSCP) analysis of the amplified products gave rise to a much greater sensitivity, up to 84% overall. The false negative samples were mainly encountered in B-ML with SmIgG and non-Ig, suggesting miss-annealing between the primers used and the template DNA because of somatic hypermutation of IgH genes in such clones. This indicates that PCR analysis is very useful in detecting the clonal IgH rearrangements in B-cell malignancies, especially in ALL and CLL, but not in B-ML corresponding to neoplasms originating from pre-germinal center naive B-cells.

Clone Cells↗

PubMed1999

[Itraconazole-induced hypokalemia in a patient with pulmonary aspergilloma].

An 80-year-old man was admitted to the hospital with a diagnosis of pulmonary aspergilloma. A new azole antifungal agent, D 0870, was administered to the patient for 7 days orally, and itraconazole (400 mg/day) was started on March 5, 1997. After 1 month of chemotherapy, facial and pretibial edema were observed and the patient's serum potassium concentration decreased to 2.5 mEq/l. A chest radiograph disclosed cardiomegaly with cardiac effusion and right pleural effusion on admission. The serum potassium concentration rose after the cessation of itraconazole therapy. The serum ITCZ concentration remained high for 2 weeks after admission. Although reports of hypopotassemia induced by ITCZ are rare, we concluded that blood concentrations should be monitored more carefully when treating pulmonary aspergilloma patients with high-dose regimens of ITCZ.

Aged↗

PubMed1999

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1997). III Secular changes in susceptibility].

Susceptibilities to various antimicrobial agents were examined for Enterococcus faecalis, Staphylococcus aureus, Echerichia coli, Klebsiella spp., and Pseudomonas aeruginosa that were isolated from patients with urinary tract infections (UTIs) in 9 hospitals during June 1997 to May 1998, and the results were compared with those obtained during the same period in earlier years. 1. E. faecalis The MIC90s of quinolones for E. faecalis isolated from uncomplicated UTIs have changed better state during the latest period. Among E. faecalis strains, those with high susceptibilities to ampicillin (ABPC) and minocycline (MINO) appeared to had decreased during period of 1995-1997, which recovered during the latest period. 2. S. aureus The sensitive strains of S. aureus to imipenem (IPM) and clindamycin (CLDM) had increased during the period of 1996-1997, but those have decreased again during the latest period. 3. E. coli The susceptibilities of E. coli to MINO have been better in the latest period with the MIC90 was ranged from 2 to 4 micrograms/ml. The susceptibilities to quinolones of E. coli isolated from complicated UTIs had decreased during the period of 1995-1997, but those have recovered during the latest period. 4. Klebsiella spp. Among Klebsiella spp. strains isolated from uncomplicated UTIs, those with low susceptibilities to almost cephems have increased in the latest period. To other antimicrobial agents, the susceptibilities of Klebsiella spp. did not show any changes during the latest period. 5. P. aeruginosa The susceptibilities to most agents of P. aeruginosa did not show any changes, the decreased susceptibilities to cefozopran (CZOP), carbapenems and monobactams of P. aeruginosa observed in 1996 appeared to have been retrieved in 1997. These susceptibility changes should be utilized in determining clinical treatments.

Anti-Bacterial Agents↗

PubMed1998

Interleukin-15 (IL-15) can replace the IL-2 signal in IL-2-dependent adult T-cell leukemia (ATL) cell lines: expression of IL-15 receptor alpha on ATL cells.

Interleukin-15 receptor (IL-15R) and IL-2R have the same beta and gamma chains, but IL-15R has a specific alpha chain distinct from that of IL-2Ralpha, which is indispensable for the high affinity binding of IL-15. In the present study, we examined four IL-2-dependent adult T-cell leukemia (ATL) cell lines for their IL-15R expression. All cell lines bound IL-15, which was not inhibited by a 100-fold excess amount of IL-2, proliferated in response to IL-15 to the same degree as to the stimulation with IL-2, and were maintained without IL-2. The responses to 1L-15 were inhibited by the antibodies against IL-2R beta or gamma chains but was not by the IL-2R alpha chain antibody. [125I]-IL-15 exhibited a single high-affinity binding with an apparent kd of 0.17 nmol/L. Reverse transcription-coupled polymerase chain reaction (RT-PCR) showed that the cell lines had the mRNA of IL-15R alpha. The cell lines also had IL-15 mRNA. Despite the presence of IL-15 mRNA, the cell lines did not secrete IL-15, and the culture supernatants of fresh ATL cells and plasma from the patients did not contain a detectable amount of IL-15 with a few exceptional cases, although fresh ATL cells also responded to IL-15. These results suggest that ATL cells have the complete form of IL-15R and respond to IL-15. Such an IL-15-dependent cell proliferation mechanism might be used in the development of ATL and for the invasion and proliferation of ATL cells in the visceral organs.

Adult↗

PubMed1998

Infections caused by multiple strains of methicillin-resistant Staphylococcus aureus--a pressing epidemiological issue.

The genotype of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from several foci in the same patient was studied to identify the rate of infections caused by multiple MRSA strains during hospitalization. Twenty-one patients with MRSA bacteraemia and other specimens diagnosed between 1990-1994 were studied. Clinical data were retrospectively collected from the medical records. Genotyping of 113 MRSA isolates was performed by pulsed-field gel electrophoresis (PFGE), using the Gene Navigator System. More than one type of MRSA was detected from different foci in eight of 21 (38%) patients, and three types were identified in a single patient. Our results indicate that epidemiological investigations must be conducted carefully, especially in immunocompromised hosts with MRSA bacteraemia, as the probability of infection with multiple strains among these patients is relatively high.

Adult↗

PubMed1998

Escherichia coli O157 interactions with human intestinal Caco-2 cells and the influence of fosfomycin.

It is not clear how Escherichia coli O157 invades human enteric epithelium and causes the haemolytic uraemic syndrome (HUS), and nor has the most appropriate treatment of E. coli O157 infection been established. Verotoxins, leucocytes and proinflammatory cytokines, such as tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and IL-8, are considered essential for the development of HUS. We used the Caco-2 cell monolayer system, well-known as an in-vitro model of human intestinal infection, to determine how E. coli O157 interacts with intestinal epithelial cells and also studied the influence of fosfomycin on the virulence of the bacteria. Results showed that the E. coli O157 used in this study did not penetrate the Caco-2 cell monolayer system, unlike Salmonella typhimurium SL1344, and verotoxin 1 (VT 1), but not VT 2, translocated across the system. In an in-vitro conventional assay, fosfomycin increased the amount of verotoxins but it did not influence penetration of bacteria and translocation of verotoxins in the Caco-2 cell monolayer system. The production of both IL-8 (a potent neutrophil activator) and TNF-alpha in the human monocytic THP-1 cell line was reduced by fosfomycin-treated basolateral medium in this system. These results indicate that fosfomycin may be a potent drug for preventing HUS caused by E. coli O157 infection.

Anti-Bacterial Agents↗

PubMed1998

Relationship between antimycobacterial activities of rifampicin, rifabutin and KRM-1648 and rpoB mutations of Mycobacterium tuberculosis.

We compared the in-vitro antimycobacterial activities of rifabutin and KRM-1648, two rifamycin derivatives, with that of rifampicin against 163 strains of Mycobacterium tuberculosis. We also evaluated the correlation between the level of resistance to rifampicin, rifabutin and KRM-1648 and genetic alterations in the rpoB gene. All 82 strains susceptible to rifampicin or resistant to rifampicin with MICs < or = 16 mg/L were susceptible to rifabutin and KRM-1648 with MICs < or = 1 mg/L. Seventy-six of 81 strains resistant to rifampicin with MICs > or = 32 mg/L were resistant to both rifabutin and KRM-1648, but with lower MICs than those of rifampicin. KRM-1648 showed more potent antimycobacterial activity than rifabutin against organisms with low MICs (< or = 1 mg/L), while rifabutin was more active than KRM-1648 against organisms with high MICs (> or = 2 mg/L). A total of 96 genetic alterations around the 69 bp core region of the rpoB gene were detected in 92 strains. Alterations at codons 515, 521 and 533 in the rpoB gene did not influence the susceptibility to rifampicin, rifabutin and KRM-1648. Point mutations at codons 516 and 529, deletion at codon 518 and insertion at codon 514 influenced the susceptibility to rifampicin but not that to rifabutin or KRM-1648. With the exception of one strain, all alterations at codon 513 and 531 correlated with resistance to the three test drugs. The resistant phenotype of strains with an alteration at codon 526 depended on the type of amino acid substitution. Our results suggest that analysis of genetic alterations in the rpoB gene might be useful not only for predicting rifampicin susceptibility, but also for deciding when to use rifabutin for treating tuberculosis. Further studies may be required to determine the usefulness of KRM-1648.

Amino Acid Sequence↗

PubMed1998

Effect of immunisation with Pseudomonas aeruginosa on gut-derived sepsis in mice.

The protective efficacy of immunisation with heat-killed Pseudomonas aeruginosa on murine gut-derived sepsis was evaluated. Mice were immunised intraperitoneally six times with heat-killed bacteria. This induced mean (SEM) serum IgG and IgM antibodies of 1792 (374.7) and 37.3 (8.9) ELISA units, respectively. Specific pathogen-free mice given P. aeruginosa strain D4 orally died of bacteraemia after administration of cyclophosphamide. Immunisation with heat-killed bacteria significantly increased the survival rate compared with that of control mice immunised with bovine serum albumin. Macroscopic observation revealed marked production of liver abscesses in mice immunised with bovine serum albumin but not in those immunised with heat-killed bacteria. Only low titres of antibody against the exoenzymes alkaline protease, elastase and exotoxin A were observed, and no significant difference between antibody titres to boiled and unboiled suspensions of sonicated P. aeruginosa was detected. This suggests that the main protective antibodies might be those specific to the heat stable antigen (lipopolysaccharide). Immunisation with heat-killed bacteria provided complete protection against death from gut-derived P. aeruginosa sepsis.

ADP Ribose Transferases↗

PubMed1998

Efficacies of alkaline protease, elastase and exotoxin A toxoid vaccines against gut-derived Pseudomonas aeruginosa sepsis in mice.

The protective efficacies of vaccines prepared from Pseudomonas aeruginosa alkaline protease, elastase and exotoxin A toxoids against gut-derived P. aeruginosa sepsis in mice were evaluated. Specific pathogen-free mice given P. aeruginosa strain D4 orally followed by cyclophosphamide (to promote translocation across the gut wall) died of bacteraemia. Mice immunised with one of the three individual toxoid vaccines were not significantly protected when compared to control mice immunised with bovine serum albumin. Combined immunisation with alkaline protease and elastase toxoids likewise showed no significant protective activity. However, combined immunisation with alkaline protease and exotoxin A toxoids significantly increased the survival rate, which reached 60% (compared with a 7.1% survival rate in the control group). These results show that alkaline protease and exotoxin A play important roles as pathogenic factors in gut-derived sepsis and that a combination of the two exoenzyme toxoids represents a logical candidate for vaccination against P. aeruginosa sepsis.

ADP Ribose Transferases↗

PubMed1998

Analysis of genetic relationships and antimicrobial susceptibility of verotoxin-producing Escherichia coli strains isolated in Nagasaki Prefecture, Japan in 1996.

A total of 19 Escherichia coli O157 isolates were obtained in Nagasaki Prefecture, in the south-western part of Japan, between 1990 and 1996. Pulsed-field gel electrophoresis (PFGE) and computer-assisted analysis were applied to determine genetic relationships among these strains. Fragment patterns of the isolates in Nagasaki, as determined by PFGE, were compared with those of isolates in other areas where large outbreaks and sporadic cases of E. coli O157 infection occurred. Similarity values of all the strains isolated in Nagasaki Prefecture were over 0.65 except for E. coli O26. Some strains were identical to the strains isolated from the areas where large outbreaks occurred. All strains were susceptible to ampicillin, fosfomycin, minocycline, amikacin, ofloxacin and sulfamethoxazole-trimethoprim.

Anti-Bacterial Agents↗