Search PubMed⌕ Search

Biomedical subjects

K Shimokata

Publications and source records attributed to K Shimokata.

At least 109 records · Page 6Linked to original sources
PubMed1996

Evaluation of Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test and Roche PCR-microwell plate hybridization method (AMPLICOR MYCOBACTERIUM) for direct detection of mycobacteria.

We evaluated the clinical utility of an rRNA amplification-based Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (AMTD) system and a PCR-based Roche AMPLICOR MYCOBACTERIUM system for direct detection of Mycobacterium tuberculosis, M. avium, and M. intracellulare. Of the 422 sputum samples from 170 patients, 137 (121 of M. tuberculosis, 14 of M. avium-M. intracellulare complex [MAC], 2 of mycobacterium other than M. tuberculosis or MAC) were culture positive with the Septi-Chek AFB system. One sample of a contaminated culture results was excluded for further analyses. The AMTD system detected all of the 121 samples which grew M. tuberculosis (sensitivity, 100%). Of the 284 culture negative samples, 28 were positive by this system (specificity, 90.1%). After resolution of the discrepant samples, based on a positive history for culture of the patient, the specificity of this system increased to 99.3%. On the other hand, the AMPLICOR system gave a positive result for 132 out of the 135 culture positive samples for M. tuberculosis or MAC (sensitivity, 97.8%). Of the 284 culture-negative samples, 37 were positive by this system (specificity, 87.0%). The specificity for this system after resolution of the discrepant samples increased to 98.9%. The agreement between the results from the AMTD system and the AMPLICOR system was 98.7%. Both of the systems are highly sensitive and specific for detecting M. tuberculosis and/or MAC directly from sputum samples within hours, and they should be recommended for routine use in the clinical microbiology laboratory.

Bacteriological Techniques↗
PubMed1996

PCR detection of metallo-beta-lactamase gene (blaIMP) in gram-negative rods resistant to broad-spectrum beta-lactams.

We applied PCR to the rapid detection of the metallo-beta-lactamase gene, blaIMP, in clinically isolated gram-negative rods. A total of 54 high-level ceftazidime-resistant strains (MICs, > 128 micrograms/ml) were subjected to PCR analyses with the blaIMP-specific primers, since the blaIMP-bearing clinical isolates tested in our previous study always demonstrated high-level resistance to ceftazidime. Twenty-two blaIMP-positive strains including 9 Pseudomonas aeruginosa, 9 Serratia marcescens, 2 Alcaligenes xylosoxidans, 1 Pseudomonas putida, and 1 Klebsiella pneumoniae strains were newly identified from 18 different hospitals in Japan. These strains were mostly isolated from urine samples and showed high-level resistance to almost every cephem, while their levels of resistance to carbapenems were diverse. The PCR analyses with novel integrase gene-specific (intI3) and acc(6')-Ib gene-specific primers suggested that the integron structure found in a large plasmid harbored by S. marcescens AK9373 was also well conserved among blaIMP-positive strains. These results imply that the blaIMP gene cassettes have been dispersing into various gram-negative rods with the help of the newly identified integron element. Thus, the PCR-aided rapid detection will be helpful for the early recognition of emerging blaIMP-positive clinical isolates which demonstrate consistent resistance to beta-lactams.

Alcaligenes↗
PubMed1996

Evaluation of immunochromatographic assay systems for rapid detection of hepatitis B surface antigen and antibody, Dainascreen HBsAg and Dainascreen Ausab.

We evaluated two immunochromatographic assays (ICAs), Dainascreen HBsAg for detecting human hepatitis hepatitis B surface antigen (HBsAg) and Dainascreen Ausab for detecting human hepatitis B surface antibody (anti-HBs) in human serum. The ICA systems are composed of a comb-shaped device that contains nitrocellulose strips on which complexes of HBsAg and anti-HBs can be visualized. The results can be read within 15 min of incubation. The limit of detection for HBsAg was 3.1 ng/ml and that for anti-HBs was 42 mIU/ml. Results of HBsAg detection agreed completely with those of conventional enzyme immunoassays (EIAs) and showed a 100% sensitivity (158 of 158 samples) and a 100% specificity (304 of 304 samples). The Dainascreen Ausab detected 184 of the 199 EIA-positive samples (sensitivity, 92.5%) and yielded 6 positive results among the 281 EIA-negative samples (specificity, 97.9%). The ICA systems are rapid and sensitive methods for detecting HBsAg and anti-HBs. They are low-cost systems that need no complex instrumentation for analysis and can be recommended for routine use in clinical microbiology laboratories.

Chromatography↗
PubMed1996

Calnexin acts as a molecular chaperone during the folding of glycoprotein B of human cytomegalovirus.

Human cytomegalovirus glycoprotein B (gB) is synthesized as a 105-kDa nonglycosylated polypeptide and cotranslationally modified by addition of N-linked oligosaccharides to a 160-kDa precursor in the endoplasmic reticulum (ER). It is then transported to the Golgi complex, where it is endoproteolytically cleaved to form the disulfide-linked mature gp55-116 complex. Pulse-chase experiments demonstrate that the 160-kDa gB precursor was transiently associated with calnexin, a membrane-bound chaperone, in the ER. The association was maximal immediately after synthesis, and they dissociated with a half-time of 15 min. Complete inhibition of binding by tunicamycin or castanospermine indicates the importance of N-linked oligosaccharides for it. Nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that during an initial stage in the biogenesis, the 160-kDa gB precursor was first synthesized as a fully reduced form and rapidly converted to an oxidized form, with a half-time of 18 min. Both forms of the gB precursor could bind to calnexin. The kinetics of the conversion from the fully reduced to the oxidized form coincided with that of dissociation of the 160-kDa gB precursor from calnexin, suggesting that the two steps are closely related.

1-Deoxynojirimycin↗
PubMed1996

[Commemorative lecture of receiving Imamura Memorial Prize. Analysis of cellular immunity against tuberculosis in man with special reference to tuberculous pleurisy and cytokines].

Because of containing of numerous immunocompetent cells, tuberculous pleurisy is a good model for analysis of local cellular immunity. When lymphocytes in pleural effusion were cocultured with purified protein derivative (PPD), they reacted to PPD and produced far more interleukin 2 (IL-2) and interferon-gamma (IFN-gamma) than did peripheral blood lymphocytes. Analysis using monoclonal antibody and complement revealed that at least the OKT4+/OKT8- T-cell subset is responsible for the antigen-specific IFN-gamma production in pleural fluid T lymphocytes. Tuberculous pleural fluid itself had far higher levels of IL-2 and IFN-gamma than malignant pleural fluid. Therefore, it is indicated that activated T lymphocytes in tuberculous pleural fluid concern the production of lymphokines at the morbid site. Treatment with IFN-gamma resulted in an increased percentage of human alveolar macrophages ingesting BCG and an increased number of ingested BCG in individual alveolar macrophage in patient with pulmonary tuberculosis. The IFN-gamma treatment also showed increased killing activity of alveolar macrophages. Through these studies, IFN-gamma is an essential cytokine which activates human alveolar macrophages and induces antimycobacterial activity. In conclusion, we could elucidate from the study of tuberculous pleurisy that exudative sensitized pleural fluid T-lymphocytes play a major role in the defence of tuberculosis at the morbid site.

Humans↗
PubMed1996

[Infection with Mycobacterium avium presenting as polypoid lesions in left upper-lobe bronchus of an immunocompetent host].

In April 1993, a 51-year-old woman had a fever, and an infiltrative shadow was seen in the left upper lobe on a chest X-ray film. Repeated sputum cultures were positive for Mycobacterium avium complex. She underwent antituberculosis therapy consisting of pyrazinamide, ofloxacin, and streptomycin. Her symptom disappeared and the abnormal shadow resolved. In January 1994, she was admitted to the hospital because of bloody sputum and abnormal chest X-ray findings consisting of a left hilar mass and atelectasis of the left upper lobe. Bronchoscopy revealed multiple polypoid lesions without necrosis in the left upper-lobe bronchus. Histological examination showed that the tumor consisted of an aggregation of lymphocytes and plasma cells, and was positive for Ziehl-Neelsen stain. The acid-fast bacillus was identified as Mycobacterium avium by the DNA probe method. Anti-tuberculosis treatment was given: rifampicin, isoniazid, sparfloxacin, and clarithromycin. Three months later, the atelectasis and the polypoid mass in the left upper-lobe bronchus had disappeared. We believe that the polypoid lesions in the left upper-lobe bronchus were due to infection by Mycobacterium avium. The patient was HIV-negative and immunocompetent. Such endobronchial lesions caused by Mycobacterium avium are rare in HIV-negative hosts.

Bronchial Neoplasms↗
PubMed1995

Analysis of elements in the substrate required for processing by mitochondrial processing peptidase.

We have recently demonstrated that synthetic peptides modeled on the extension peptide of malate dehydrogenase can be a good substrate of mitochondrial processing peptidase and that arginine residues present at positions -2 or -3 and distant from the cleavage point were important for recognition by the enzyme (Niidome, T., Kitada, S., Shimokata, K., Ogishima, T., and Ito, A. (1994) J. Biol. Chem. 269, 24719-24722). We further investigated the elements required for substrates of the protease. To analyze the reaction by a more rapid yet quantitative method, we have developed intramolecularly quenched fluorescent substrates. Using the fluorogenic substrates we demonstrated that at least one of the proline and glycine between the distal and proximal arginine residues was also important while other connecting sequences were dispensable. In addition, the protease showed considerable preference for aromatic and, to a lesser extent, hydrophobic amino acids in the P1'-position. These results together with the previous data suggest that the proximal and distal arginine residues, proline and/or glycine between them, and P1' amino acid could be critical determinants for the specific cleavage of the substrates by the protease.

Amino Acid Sequence↗
PubMed1995

Retroviral transfer of HSV1-TK gene into human lung cancer cell line.

We used a recombinant retrovirus as one of the potential vectors for human gene therapy to transfer a drug sensitivity gene into human lung cancer cells. The gene encoding the thymidine kinase (TK) of herpes simplex virus type 1 (HSV1) was used as the drug sensitivity gene. The antiherpes drugs acyclovir (ACV) and ganciclovir (GCV) were chosen to test the HSV1-TK activity transferred into the human lung cancer cell lines. The rationale for this approach was that ACV and GCV are nucleoside analogs specifically converted by HSV1-TK to a toxic form capable of inhibiting DNA synthesis or disrupting cellular DNA replication. The results obtained from our experiments demonstrate that the retroviral vector-mediated HSV1-TK gene transfer leads to ACV- and GCV-dependent cytotoxicity in human lung cancer cell lines, including both small-cell carcinoma and non-small-cell carcinoma. Although the gene transfer of HSV1-TK gene into tumor cells would be one model for gene therapy to control lung cancer, further investigations are necessary for the proper choice of the therapeutic gene and vector targeting such as tumor cell specific delivery of the gene or tumor cell specific expression of the transduced gene.

Acyclovir↗
PubMed1995

A putative metal-binding site in the beta subunit of rat mitochondrial processing peptidase is essential for its catalytic activity.

Mitochondrial processing peptidase (MPP) consists of alpha- and beta-subunits (alpha-MPP and beta-MPP). beta-MPP has a putative metal-binding sequence (HXXEH). To determine whether the sequence of beta-MPP is essential for the enzymatic activity, we individually mutated the histidines and glutamic acid to arginines and glutamine, respectively. The wild-type and mutated beta-MPPs were co-expressed with alpha-MPP in Escherichia coli. All three mutants had completely lost the activity, whereas the lost activity was recovered on the addition of wild-type beta-MPP. The activity of the wild-type enzyme was reduced by the mutant beta-MPPs. We conclude from these observations that the HXXEH region is involved in the formation of the active site and that beta-MPP is the catalytic subunit of MPP.

Adrenodoxin↗
PubMed1995

Cerebral infarction due to a spontaneous tumor embolus from lung cancer.

A cerebral infarction of the left occipital lobe developed in a 65-year-old man with squamous cell carcinoma of the right lung. Neurological examinations and brain CT showed findings typical of ordinary infarction. Postmortem examination revealed a tumor embolus within the posterior cerebral artery. Such spontaneous tumor emboli large enough to obstruct a larger-sized artery are rare.

Aged↗
PubMed1995

Expression of tumor necrosis factor receptors in human lung cancer cells and normal lung tissues.

The purpose of this study was to investigate the expression of tumor necrosis factor (TNF) receptors for the control of the biologic action of TNF-alpha in lung cancer cells and normal lung tissues. Lung cancer specimens and normal lung tissues were freshly obtained in pairs from 15 patients who underwent surgery for lung cancer. Thirteen lung cancer specimens expressed the 55 kDa TNF receptor messenger RNA (mRNA), whereas only six lung cancer specimens expressed the 75 kDa TNF receptor mRNA by Northern blot analysis. The 55 kDa and 75 kDa TNF receptors mRNA were detected in all and 11 normal lung tissues, respectively. All four lung carcinoma cell lines examined expressed the 55 kDa TNF receptor mRNA, but only RERF-LC-MS (MS) expressed both the 55 kDa and 75 kDa TNF receptors mRNA. Immunohistochemical examination revealed that lung cancer cells expressed the 55 kDa TNF receptor, but not the 75 kDa TNF receptor at the protein level. In normal lung tissues, the 55 kDa TNF receptor was detected in alveolar macrophages, bronchioles, and some small vessels. The 75 kDa TNF receptor was detected in alveolar macrophages. All four lung carcinoma cell lines examined exhibited the only 55 kDa TNF receptor. TNF-mediated tumor cell lysis was observed in all lung carcinoma cell lines that exhibited the 55 kDa TNF receptor except A549, which is a TNF-insensitive cell line. In surface binding assays, specific surface binding of TNF-alpha to TNF-insensitive cell line A549 was observed to be about half that of TNF-sensitive cell lines. We demonstrated the expression of two distinct TNF receptors in human lung cancer and normal lung tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1995

Clinical and pharmacologic analysis of hyperfractionated daily oral etoposide.

PURPOSE: The antitumor effect of etoposide is increased by maintaining a low blood level, whereas high peak levels may cause myelotoxicity. We investigated whether a constant low blood level could be obtained by the administration of oral etoposide three times daily. PATIENTS AND METHODS: Nineteen patients with non-small-cell lung cancer were treated with oral etoposide (25 mg three times daily for 21 days) as monotherapy or in combination with cisplatin 80 mg/m2. A pharmacokinetic model that predicted the mean blood concentration (Cmean) was developed in the 10 patients on etoposide monotherapy and validated in the nine patients on combination chemotherapy. Pharmacodynamic relationships were evaluated in each group. RESULTS: Etoposide dose per body-surface area ranged from 45 to 63 mg/m2/d (median, 53), but did not correlate with plasma level. Cmean was 1.1 +/- 0.3 micrograms/mL. Peak concentrations ranged from 0.6 to 2.5 micrograms/mL. The intrapatient coefficient of variation for plasma etoposide concentrations was 22% +/- 10%. Cmean was accurately estimated as follows: Cmean = 0.098 + 0.413 x C0 + 0.458 x C2 (r = .97, P = .0001), where C0 and C2 represent concentrations before and 2 hours after administration. This model was unbiased (mean predictive error [MPE], 0.0 microgram/mL) and precise (root mean square error [RMSE], 0.1 microgram/mL). Leukopenia was the major toxicity. The surviving fraction of leukocytes (SF; nadir count/pretreatment count) was correlated to Cmean as follows: SF = 0.87 - 0.34 x Cmean (r = .67, P = .03) in the monotherapy group and SF = 0.64 - 0.33 x Cmean (R = .77, P = .03) in the combination chemotherapy group. Two and four patients treated with monotherapy and combination chemotherapy showed responses, respectively. All responders had a Cmean > or = 1.0 microgram/mL. CONCLUSION: Hyperfractionated oral etoposide achieveda stable plasma level that could be predicted by measurement at only two times.

Administration, Oral↗
PubMed1995

Expression of cell adhesion molecules in the lungs of patients with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic inflammatory disorder restricted to the lungs. Leukocyte entry into the area of inflammation is regulated, at least partly, by endothelial expression of leukocyte-selective cell adhesion molecules (CAMs). To investigate the relevance of these CAMs to the accumulation of leukocytes in IPF, we examined the expression of E-selectin (endothelial leukocyte adhesion molecule-1; ELAM-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) by immunohistochemistry in lung tissue from nine patients with IPF and five nonsmoking normal subjects. The results demonstrated that in normal lungs, ICAM-1 was weakly expressed on endothelial cells, but neither E-selectin nor VCAM-1 was detected. In the lungs of patients with IPF, E-selectin expression on endothelial cells was restricted to honeycombing regions. Endothelial expression of ICAM-1 was increased throughout the tissue, but VCAM-1 was not detected in IPF. The distribution of leukocytes in lungs with IPF consisted of mostly lymphocyte accumulation in the interstitium and neutrophil accumulation within the airspaces of honeycomb regions. These results suggest that E-selectin may play a role in the recruitment of neutrophils in regions of honeycombing and that ICAM-1 may play a role in lymphocyte recruitment into the interstitium in addition to contributing to neutrophil recruitment in regions of honeycombing in patients with IPF.

Aged↗
PubMed1995

Detection of Pneumocystis carinii, Mycobacterium tuberculosis, and cytomegalovirus in human immunodeficiency virus (HIV)-infected patients with hemophilia by polymerase chain reaction of induced sputum samples.

The purpose of this study was to diagnose the initial stage of acute pulmonary infections due to Pneumocystis carinii (P. carinii), Mycobacterium tuberculosis (M. tuberculosis), and cytomegalovirus (CMV) by polymerase chain reaction (PCR) combined with the induced sputum method in hemophilia patients infected with human immunodeficiency virus (HIV). Induced sputum and PCR were obtained at each outpatient visit or when any respiratory symptoms were present during a one-year period. All patients with a CD4+ count of less than 200 x 10(6)/l were given prophylactics against P. carinii pneumonia (PCP). PCR was conducted 111 times in 29 patients. M. tuberculosis DNA was detected in 1 patient and CMV DNA in 4 patients. P. carinii DNA was not detected. PCR on induced sputum samples is sensitive for the rapid detection of the initial stage of respiratory events. PCP prophylaxis changes the clinical manifestations of HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Survey of the state of bronchography in Japan].

Bronchography is not routinely done. We analyzed the state of bronchography with questionnaires returned from 57 hospitals. Bronchography is now done at 30 hospitals. The number done in 1992 ranged from 1 to 27 (median 3). Peripheral lung cancer and bronchiectasis were the two most frequent diseases for which bronchography was done. In other hospitals, bronchography was once done, but had been stopped. Two reasons for discontinuation of bronchography are: recent progress in radiographic diagnostic techniques such as high resolution CT, and discomfort of the patient. Now that propyliodone is no longer available, some hospitals may use iopydol-iopydone or iopamidol instead. It is necessary to elucidate the true need for bronchography and for an appropriate contrast medium to take the place of propyliodone.

Bronchography↗
PubMed1995

[Some problems concerning local cellular immunity in tuberculosis].

Tuberculous pleurisy is restricted to the pleural cavity and profuse pleural fluid, which contains numerous immunocompetent cells, is easily obtained. Therefore, tuberculous pleurisy is a good model for the study of local cellular immunity. The characteristics and function of lymphocytes in both pleural exudate and peripheral blood were studied. The pleural fluid had more T-lymphocytes than the peripheral blood. To evaluate predominant T-lymphocyte function in tuberculous pleural exudate, we studied the reactions of the lymphocytes to the specific antigen. When lymphocytes in pleural effusion were cocultured with purified protein derivative (PPD), they reacted to PPD and produced far more interferon-gamma (IFN-gamma) than did peripheral blood lymphocytes. Thus, exudative-sensitized lymphocytes in morbid sites reacted to the specific antigen more strongly. These observations indicate the presence of local cellular immunity in tuberculous pleurisy at the morbid site. It would be very interesting to know which T-cell subset produces IFN-gamma. When pleural fluid T lymphocytes were treated with OKT4 monoclonal antibody and complement, a significant decrease in IFN-gamma production was observed in all patients examined, whereas no definite decrease in IFN-gamma production was found after treatment with OKT8 monoclonal antibody and complement. These results suggest that at least the OKT4+/OKT8- T-cell subset is responsible for the antigen-specific IFN-gamma production in pleural fluid T lymphocytes. With the cooperation of macrophages or monocytes, pleural fluid T lymphocytes produced a significant level of interleukin 2 (IL-2) in the presence of PPD. Tuberculosis pleural fluid macrophages promoted greater IL-2 production than blood monocytes from either tuberculosis pleural fluid or blood T lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1995

[Future directions of gene therapy for lung cancer].

Failure to achieve sustained therapeutic responses with conventional medical therapies has presented a challenge to gene therapy as a new approach to lung cancer. We used an allo-major histocompatibility complex class I gene (H-2Kb), and a gene encoding the thymidine kinase of herpes simplex virus type (HSV1-TK) as a drug sensitivity gene. The H-2Kb gene-transfected clones of mouse tumor cells were rejected completely by syngeneic DBA/2 mice. Furthermore, the mice that had rejected the H-2Kb gene-transfected clone became immune to and rejected the parental mouse tumor cells. Transfer of the retroviral vector-mediated HSV1-TK gene led to ganciclovir-dependent cytotoxicity in human lung cancer cells both in vivo and in vitro. Although these findings may lead to gene therapy to control lung cancer, further study is needed to determine the proper gene for targeting distant tumor cells, and the cell-specific promoter/enhancer sequences that regulate the tumor cell-specific expression of the transduced gene.

Animals↗