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Biomedical subjects

H Tasaka

Publications and source records attributed to H Tasaka.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Identification of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium tuberculosis complex by Gen-Probe Rapid Diagnostic System].

DNA probe testing for Mycobacterium avium, Mycobacterium intracellulare and Mycobacterium tuberculosis complex (MTC) was performed using Gen-Probe Rapid Diagnostic System (Gen-Probe Inc., San Diego, Calif., U.S.A.). By DNA probe test carried out blindfold for 48 mycobacterial strains with code numbers obtained from Kyoto University (Prof. F. Kuze), 13, 7, and 5 strains were identified as to be M. avium, M. intracellulare, and MTC, respectively. The diagnostic specificity and sensitivity of this testing were 100%. In this experiment, % hybridization of M. avium complex (MAC) and MTC were 25-55% and 45-52%, respectively. DNA probe test for 54 MTC strains including M. tuberculosis, M. bovis, M. africanum and M. microti revealed that 53 strains, except for one strain donated as a niacin-negative M. tuberculosis, reacted with MTC probe but not with MAC-probes. The one exceptional strain reacted with both the MTC- and M. avium-probes. However, when ten colonies randomly isolated from this strain on 7H11 agar plate were subjected to the DNA probe test again, all of these colonies reacted with M. avium probe, but not with MTC probe. Moreover, one representative colony was found to have alpha-antigen specific for the MAC.

DNA Probes↗
PubMed1991

[Reactivities of various mycobacteria species against DNA probes (Gen-Probe Rapid Diagnostic System) specific to Mycobacterium tuberculosis complex, Mycobacterium avium and Mycobacterium intracellulare].

Various mycobacterial species (22 species, 178 strains) were studied for their reactivity to DNA probe specific for Mycobacterium tuberculosis complex (MTC), M. avium or M. intracellulare, using Gen-Probe Rapid Diagnostic System (Gen-Probe Inc., San Diego, Calif., U.S.A.). All the MTC strains, including M. tuberculosis, M. africanum, M. bovis and M. microti reacted with MTC-DNA probe at the % hybridization value of 42.8-51.9% (values higher than 10% are regarded as positive), but their reactivity to MAC-DNA probes (0.8-2.5%) was under the cut off value (10%). The test strains (28 strains) of M. avium complex (MAC) segregated into two groups on the basis of reactivity to DNA probes specific for M. avium and M. intracellulare, that is, one group (16 strains) positively reacted with M. avium-probe but not with M. intracellulare-probe, and the other group (12 strains) showed the converse reactivity. The two groups did not show a reactivity with MTC-probe higher than the cut off value. Nontuberculous mycobacteria other than MAC, including M. kansasii, M. marinum, M. simiae, M. asiaticum, M. scrofulaceum, M. gordonae, M. szulgai, M. malmoense, M. xenopi, M. gastri, M. nonchromogenicum, M. terrae, M. triviale, M. fortuitum, and M. chelonae (subsp. abscessus and chelonae) reacted with neither MTC- nor MAC-probe and values for % hybridization (0.6-3.6%) were lower than the cut off value. These findings indicate extremely superior specificity of the DNA probes (Gen-Probe) for MTC, M. avium and M. intracellulare, thereby indicating the usefulness of Gen-Probe Rapid Diagnostic System for the MTC and MAC in clinical use.

Animals↗
PubMed1991

[Study on recombinant BCG].

For the purpose to establish the system to express foreign antigen from Mycobacterium bovis BCG. We have cloned, sequenced and expressed genes for secreting proteins, alpha antigen, MPB64, MPB57 and MPB70 from M. bovis BCG. The upstreams and structural genes were characterized. The gene for alpha antigen of Mycobacterium kansasii was also characterized. The gene for alpha antigen of M. kansasii (k-alpha) was chosen for the further study at first. This gene was fused with shuttle plasmid PIJ666-PAL5000 obtained from T. Kisser and transfected to M. bovis BCG (Tokyo). Transformant was obtained by a selection with kanamycin. It was able to secrete k-alpha antigen. DNA-containing a B-cell epitope (Glu-12-Leu-Asp-Arg-Trp-Glu-Lys-Ile-19) of human immunodeficiency virus type 1 P17 gag was fused to this vector at C terminal of k-alpha. Using this vector, we have succeeded to express foreign antigen in M. bovis BCG. The products were analyzed in one or two dimensional electro-phoresis. The results thus obtained will be reported elsewhere.

Amino Acid Sequence↗
PubMed1990

Acute leukemia with normal platelet count at diagnosis.

Thirty-six (17.8%) of 202 children with acute lymphoblastic leukemia (ALL) and 2 (3.7%) of 54 children with acute nonlymphoblastic leukemia (ANLL) had a platelet count over 150 x 10(9)/l at diagnosis. Children with ALL and a platelet count over 150 x 10(9)/l were analysed in detail. The ALL patients without thrombocytopenia tended to be male predominant and had less frequent bleeding manifestations (p less than 0.01). These patients without thrombocytopenia had also significantly less marked leukocytosis (p less than 0.01), less severe anemia (p less than 0.05) and lower percentages of bone marrow blasts (p less than 0.05) than those with thrombocytopenia. In addition, ALL patients without thrombocytopenia had a significantly higher probability of continuous complete remission than those with thrombocytopenia (p less than 0.01).

Child↗
PubMed1990

Establishment of a foreign antigen secretion system in mycobacteria.

In order to develop recombinant Mycobacterium bovis BCG into a useful multivaccine vehicle, we established a foreign antigen secretion system in mycobacteria in which an extracellular alpha antigen of Mycobacterium kansasii was utilized as a carrier. By using this system, a B-cell epitope (Glu-12-Leu-Asp-Arg-Trp-Glu-Lys-Ile-19) of human immunodeficiency virus type 1 p17gag, which was identified by a fusion protein-based method, has been successfully obtained from BCG along with the alpha antigen. This is the first report of expression and secretion of a foreign viral antigen from BCG. It is possible that the system can become a universal vaccination vehicle applicable to protection against various infectious diseases.

Amino Acid Sequence↗
PubMed1990

Cloning and expression of the gene for the cross-reactive alpha antigen of Mycobacterium kansasii.

The gene for the extracellular alpha antigen of Mycobacterium kansasii was cloned by using the alpha-antigen gene fragments of M. bovis BCG as probes. Gene analysis revealed that this gene encodes 325 amino acid residues, including 40 amino acids for the signal peptide, followed by 285 amino acids for the mature protein. A comparison of the nucleotide sequences of the genes isolated from these two mycobacterial species showed that the levels of DNA and amino acid homology were 84.8 and 89.1%, respectively. The hydropathy profiles were also compared, and two highly changed hydrophilic regions were observed, which might account for the antigenic diversity of this antigen or its acquirement of antigenic specificity.

Amino Acid Sequence↗
PubMed1990

Identification of various serovar strains of Mycobacterium avium complex by using DNA probes specific for Mycobacterium avium and Mycobacterium intracellulare.

Reference strains of the Mycobacterium avium complex (MAC) belonging to serovars 1 to 28 were examined with DNA probes (Gen Probe Rapid Diagnostic System for the MAC; Gen Probe Inc., San Diego, Calif.) specific for either M. avium or Mycobacterium intracellulare. This study revealed that the earlier designations of the MAC serovars, in which serovars 1 to 3 and 4 to 28 were regarded as M. avium and M. intracellular, respectively, should be revised as follows. First M. avium includes serovars, 1 to 6, 8 to 11, and 21. Second, M. intracellulare includes serovars 7, 12 to 20, and 25. However, other serovars, such as serovars 22 to 24 and 26 to 28, involve M. intracellulare, Mycobacterium scrofulaceum, and MAC that are lacking in the reactivity with either DNA probe and that are too disordered to enable a conclusive description here, particularly concerning their taxonomic positions in the MAC.

Antigens, Bacterial↗
PubMed1990

[Prognosis of childhood mediastinal lymphoma].

Between 1973 and 1989, 16 children with non-Hodgkins lymphoma (NHL) with a mediastinal mass (MM) were treated at our institution with multi-agent chemotherapy and radiotherapy. They also received central nervous system (CNS) prophylaxis including intrathecal methotrexate administration (14 cases) and cranial irradiation (7 cases). Twelve were boys and 4 girls. Median age was 11 +/- 3. One patient died of air way obstruction one day after admission. Fourteen of 15 patients entered into complete remission (CR) and one patient partial remission. Five remains in CR 7 to 175 months after diagnosis (median 76 months). Nine patients relapsed in the bone marrow (3 cases), CNS (3), testicles (1), neck lymph node (1) and bones plus kidneys (1). Of these, 7 patients died within 13 months after initial relapse. The disease free survival (DFS) and overall survival of all patients were 27% and 33%, respectively. Analysis of the prognostic factors among patients with MM+ -NHL revealed that the serum LDH level below 1,000IU/l was a good prognostic sign. Other factors such as age, stage, initial WBC count, size of MM and response of the MM to the initial treatment did not correlate with DFS. Because of its rarity and the poor treatment result, we need more aggressive treatment program by a multiinstitutional study for MM+ -NHL.

Adolescent↗
PubMed1990

[Treatment results of bone marrow transplantation in Kyushu Cancer Center. Bone Marrow Transplantation Team].

Twenty children with various hematological malignancies (nine with acute lymphoblastic leukemia, eight with acute non-lymphoblastic leukemia, two with chronic myelogenous leukemia, one with malignant lymphoma and one with 7-monosomy) and four with severe aplastic anemia were treated with allogeneic or syngeneic bone marrow transplantation (BMT) between September 1977 and September 1988. Eleven patients are surviving currently and ten are disease free 8 to 51 months after BMT. Conditioning regimen consisted of total body irradiation (TBI) and cyclophosphamide in twenty patients. Two patients did not receive TBI. Graft failure was observed in five patients and complete recovery of recipient marrow was seen in two of them. Eleven patients developed acute graft-versus-host disease (GvHD) with grade I-II in eight patients. Three patients suffered from chronic GvHD. Seven patients with acute leukemia relapsed and all but one died of leukemia. Early death occurred in two undergone BMT in poor clinical conditions. Performance status in 100% in surviving patients except one. Efforts to improve these results are that BMT should be considered early in the course of their disease for patients who are at risk for relapse with conventional chemotherapy and improved conditioning regimens to reduce leukemia relapse after BMT for patient with the second or subsequent remission.

Adolescent↗
PubMed1989

Improved survival rates in children over 1 year of age with stage III or IV neuroblastoma following an intensive chemotherapeutic regimen.

Combined chemotherapeutic regimens of (1) cyclophosphamide (40 mg/kg x two days), (2) cisplatinum (20 mg/m2 x five days) plus VM-26 (100 mg/m2), and (3) Adriamycin (60 mg/m2) plus DTIC (250 mg/m2 x five days) were prescribed for 42 Japanese children greater than 1 year of age with stage III or IV neuroblastoma. The protocol was separated into three forms (A, B, and C) from the combination pattern of three such high-dose courses. The cumulative survival rates for those with stages III and IV 48 months after initiation of therapy were 76.2% and 20.1%, respectively, and the overall rate was 36.7%. The tumor disappeared during the course of treatment in 25 of 42 children (59.5%). The 48-month survival rate was superior in patients greater than 5 years of age than younger patients (P less than .01). Even in patients with a tumor originating in the suprarenal region, the 48-month survival rate was 30.5%. Among 12 patients in whom the N-myc oncogene was measured, one of five with one to ten copies of amplification died, whereas all seven with greater than ten copies died or had a recurrence. Thus, the present chemotherapeutic regimens, in particular alternate administration of each high-dose course, considerably improved the survival of patients with stage III neuroblastoma. More aggressive protocols are needed for those with stage IV neuroblastoma who are greater than 1 year of age, particularly in those with an amplified N-myc oncogene.

Adolescent↗
PubMed1989

Identification and partial characterization of Mycobacterium avium and Mycobacterium intracellulare by using DNA probes.

We attempted to identify the Mycobacterium avium complex (MAC) isolated in Japan by using DNA probes specific for M. avium or Mycobacterium intracellulare (Gen-Probe Rapid Diagnostic System for MAC; Gen-Probe, Inc., San Diego, Calif.). The source and drug susceptibility distributions were examined. This assay system proved to be rapid, sensitive, specific, and reliable for identification of MAC and of the species as either M. avium or M. intracellulare. The DNA probe test showed that of the generally accepted MAC serovars, serovars 1 to 6, 8 to 11, and 21 belonged to M. avium and 7 and 12 to 20 belonged to M. intracellulare. Moreover, with the DNA probe test we found that the distribution patterns of M. avium and M. intracellulare isolates in Japan differed depending on the district in which MAC was isolated. The ratio of M. avium was much higher in eastern Japan. In Tokai and Shimane districts, the ratio of M. avium and M. intracellulare isolates significant in human disease was related to that of isolates from soil and house dust (natural sources). In M. avium, human disease-associated isolates were more resistant to rifampin, streptomycin, and kanamycin than were isolates from natural sources. However, this source dependence was not evident for M. intracellulare. In human disease-associated MAC, M. avium isolates were more resistant to most agents, except for quinolones, than were M. intracellulare isolates.

Animals↗
PubMed1989

Pulmonary and pleural involvements at initial diagnosis in children with malignant neoplasm.

Seventeen cases of pediatric malignant neoplasm with pulmonary and/or pleural lesions shown by chest radiography at initial diagnosis were reviewed and analyzed. Respiratory symptoms such as dyspnea, tachypnea, and chest pain were observed on admission in approximately one-half of them. The initial chest radiography showed pleural lesions in 7 of the 17, pulmonary lesions in 8, and both pulmonary and pleural lesions in 2. Unilateral or bilateral pleural fluids were observed in all of the seven patients with pleural lesions, and malignant cells were confirmed in the pleural fluid of all patients. The radiographic patterns of the eight patients with pulmonary lesions were solitary nodule in two, multiple nodules in two, diffuse miliary nodules in three, and diffuse honeycomb in one. Histological examination of the pulmonary lesion was performed in six patients at the initial diagnosis or after death, while in the remaining two primary or other metastatic sites were examined. The two patients with both pulmonary and pleural lesions showed multiple nodules or infiltrates with pleural fluid on chest radiography. Increased malignant cells were detected in the pleural fluid of both patients. In all cases, the lesions gradually or rapidly disappeared with multidrug chemotherapy. The review confirms the need for a combination of complete radiographic and pathological analysis at the time of initial diagnosis of malignant neoplasm in children to distinguish other causes such as infectious complications.

Adolescent↗
PubMed1989

[Computed tomography of thymic hyperplasia in older children].

Computed tomography (CT) findings of 8 cases of thymic hyperplasia in children aged 7 to 15 years were retrospectively analyzed in comparison to 8 cases of tumors of anterior mediastinum. All cases of thymic hyperplasia retained a somewhat triangular or arrowhead-like shape at least on one side while tumors showed bilateral globular contour with lobulated border. No compression of the air way or pleural fluid was observed in thymic hyperplasia. These CT features are useful for making a diagnosis of thymic hyperplasia when an older child is presented with an anterior mediastinal mass on chest X-ray.

Adolescent↗
PubMed1988

Dopaminergic neuroblastoma as a poor prognostic subgroup.

Clinical and biological significance of increased urinary excretion of dopamine in Japanese children with neuroblastoma was investigated. There was an increase in dopamine excretion in 19 of 29 patients (66%) and 15 of 19 in stages III and IV (79%). When the ratio of noradrenaline and dopamine was divided into two at the value of 3.5 x 10(-2), the disease-free survival rate was four of 16 (25%) in the low ratio group and nine of 19 (69%) in the high ratio group. In five patients, the urinary analysis revealed that only the level of dopamine was elevated before initiation of the therapy. The common features of these patients were as follows: (1) the age at diagnosis was 1 to 4 years; (2) all originated from the suprarenal region; (3) stages were advanced III or IV; and (4) the prognosis was poor. N-myc oncogene of the primary tumor was evident in three, and all were amplified to 32, 37, and 112 copies. These observations suggested that the immaturity of catecholamine metabolism may correlate to the poor prognosis and that "dopaminergic neuroblastoma" may be a clinical subentity of poor prognostic neuroblastoma.

Adrenal Gland Neoplasms↗
PubMed1988

Cloning and expression of the Mycobacterium bovis BCG gene for extracellular alpha antigen.

The gene for the extracellular alpha antigen of Mycobacterium bovis BCG was cloned by using a single probe restricted to G or C in the third position. This technique should have great potential for the isolation of mycobacterial antigen genes. The gene analysis revealed that the alpha antigen gene encoded 323 amino acid residues, including 40 amino acids for signal peptide followed by 283 amino acids for mature protein. This is the first report on the structure of the mycobacterial signal peptide. The promoter-like sequence and ribosome-binding site were observed upstream of the open reading frame. In the coding region, the third position of the codon showed high G + C content (86%). The gene was expressed as an unfused protein in Escherichia coli by using an E. coli expression vector. This protein, which reacted with polyclonal antibody raised against alpha antigen from Mycobacterium tuberculosis, would be applicable to the immunodiagnosis of tuberculosis.

Amino Acid Sequence↗