Identification of integrated human herpesvirus 6 DNA in early pre-B cell acute lymphoblastic leukemia.
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Biomedical subjects
Publications and source records attributed to H Taguchi.
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The abnormal lymphocytes in adult T cell leukemia (ATL) reveal a peculiar morphology that is characterized by indented or lobulated nuclei. While human T lymphotropic virus type I (HTLV-I) is thought to be integrated in ATL cells, the correlation between the nuclear irregularities and HTLV-I infection is obscure. We have devised a novel single cell polymerase chain reaction (PCR) technique to examine the integration of HTLV-I provirus genome in cells from two patients with ATL. To isolate single cells, peripheral blood smears were prepared on thin polyester slides and stained with May-Grünwald-Giemsa. Morphologically defined single cells were cut out after light microscopy. The HTLV-I DNA sequences were detected not only in ATL cells but also in normal-looking lymphocytes. This novel PCR method may provide a valuable tool for understanding the molecular events associated with HTLV-I infection at the single cell level.
Human herpesvirus 6 (HHV-6) genome has been found in several human lymphoid malignancies, but configuration of the HHV-6 genome has not been well delineated. We established the HHV-6-positive, Epstein-Barr virus-negative Burkitt's lymphoma cell line Katata. In this study we investigated the status of the HHV-6 genome in Katata cells. Neither linear nor circular HHV-6 DNA was detected by Gardella gel analysis. The fluorescence in situ hybridization technique enabled us to directly visualize the integrated HHV-6 DNA at the single-cell level. Only one integrated site of viral DNA was detected in metaphase chromosomes and it was preferentially located at the long arm of chromosome 22 (22q13). Treatment of the cells with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or with calcium ionophore A23187 led to induction of the HHV-6 immediate-early gene as well as the late gene. Sodium n-butyrate also gave rise to expression of the HHV-6 genes. The TPA inducibility was synergistically enhanced when combined with A23187 or n-butyrate. Our study provides, for the first time, an in vitro model system of latent HHV-6 infection whose genome is integrated into host DNA of lymphoma cells.
Ataxia-telangiectasia (A-T) is a multisystem recessive disease characterized by cerebellar ataxia, oculocutaneous telangiectasias, immunodeficiency and increased risk of cancer. The ATM gene, responsible for A-T, was recently cloned at human chromosome band 11q22-23, a region of frequent alterations in childhood acute lymphoblastic leukaemia (ALL). Children with A-T frequently develop T-ALL. We investigated 18 T-ALL samples for ATM mutations and loss of heterozygosity (LOH) at the ATM locus. No mutations of ATM were found within the coding region in the 18 T-ALL samples, and LOH at the ATM locus was detected in three. The ATM gene appears to be an infrequently altered tumour suppressor gene in childhood T-ALL.
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A case of pure red cell aplasia (PRCA), myasthenia gravis (MG) and thymoma is reported. A 70-year-old woman presented with severe anemia. She had been diagnosed as having MG 8 years earlier and her symptoms were adequately controlled with ambenonium chloride. When she visited our hospital, her hematocrit was 13.7% with a hemoglobin concentration of 4.7 g/dl and her reticulocyte counts were persistently abnormal at 0.1%. Although both direct and indirect Coombs' tests were positive, there was no evidence of hemolysis. Routine screening tests for other etiologies of anemia were negative. Serological tests for anti-DNA and anti-acetylcholine receptor antibodies gave positive results. A bone marrow examination revealed severe erythroid hypoplasia. PRCA was diagnosed and the patient was treated with periodic transfusions. A lateral view chest roentgenogram and a computed tomography scan of the thorax showed the presence of an anterior mediastinal mass which was suspected to be thymoma. The patient underwent thymothymectomy and the tumor was diagnosed as a thymoma. Although the patient received no treatment for MG and PRCA after surgery, her hematological test results rapidly improved and she was discharged from the hospital on the 29th postoperative day. At that time, her hematocrit was 33.2%, her hemoglobin concentration was 10.0 g/dl, her peripheral reticulocyte level was 1.8% and her left partial ptosis had improved. She is doing well, 9 months after surgery. For a patient to remain in remission without treatment for PRCA and MG after thymothymectomy is extremely rare.
Among the various virulence factors of Helicobacter pylori the role of its heat shock protein 60 (HSP60, HspB) in mucosal inflammation after H. pylori infection was examined. In flow cytometric analysis, the expression of HSP60 on the cell surface was different, depending on the H. pylori strain used. The HSP60 epitope was also detected on the surface of both human gastric cancer cells (MKN45, KATOIII, and MKN28) and human gastric biopsy specimens. The intensity of the expression of HSP60 on the cell surface correlated significantly with the adhesion of H. pylori to MKN45 cells, but not with urease activity and production of vacuolating cytotoxin. A monoclonal antibody to H. pylori HSP60 inhibited the adhesion of H. pylori to MKN45 cells. These results suggest that HSP60 of H. pylori might act as an important virulence factor after H. pylori infection.
Monoclonal antibodies (MAbs) that inhibit adhesion of Helicobacter pylori to human gastric cancer (MKN45) cells were established to clarify the mechanism of adhesion of H. pylori. Of 53 hybridoma clones screened by the primary inhibition assay for adhesion, MAb A20 of IgM class was selected on the basis of both its reactivity to whole cells of H. pylori by ELISA and its inhibitory effect on adhesion of H. pylori. The adhesion of H. pylori strain TK1029 to MKN45 cells was inhibited by MAb A20, depending on the concentration of the MAb. The MAb recognised the surface antigen, lipopolysaccharide (LPS) of H. pylori, suggesting that LPS is associated with adhesion of H. pylori to human gastric epithelial cells.
The in vitro antifungal activity of D0870 against eight isolates of fluconazole-resistant Candida albicans was compared with that of itraconazole, ketoconazole and miconazole. The colorimetric MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide] assay was used to assess the antifungal activities. The 50% minimum inhibitory concentration (MIC50) of D0870 was below 0.031 microgram ml-1 for seven isolates and 0.25 microgram ml-1 for one isolate. The activity of D0870 was superior to that of the other azoles. Ketoconazole was the most effective azole next to D0870. Therefore, the new bis-triazole, D0870, is expected to be promising for the therapy of fluconazole-resistant candidosis. The present data also confirmed that the MTT assay may be useful for evaluation of resistance and detection of resistant C. albicans.
The mitochondrial morphology of live Candida albicans samples treated with several imidazoles (miconazole, econazole and clotrimazole) was observed with a fluorescent carbocyanine probe, 3,3'-dihexyloxacarbocyanine [diO-C6-(3)], under a fluorescence microscope. Nearly all non-treated C. albicans cells carried only long tubular mitochondria. Treatment with antimycotics at half the minimum inhibitory concentrations (MIC100) rapidly induced mitochondrial cleavage or fragmentation, which was followed by recovery to the normal tubular morphology within 1 h. Exposing the yeast to drugs at concentrations higher than the MICs resulted in the development of swollen mitochondria or amorphous bodies. These phenomena were concentration dependent. The fluorescence images were also compared with ultrastructural images obtained by transmission electron microscopy.
BACKGROUND: It has been postulated that interstitial cystitis can be induced by an allergy. This is partly based on the observation that many patients with interstitial cystitis also have allergic diseases. In this study, an allergic evaluation was conducted on patients with interstitial cystitis complicated by bronchial asthma, a typical allergic disease. METHODS: Clinical histories were obtained and biopsy specimens from the vesical walls of the study patients were examined histologically. Cutaneous tests and IgE radioallergosorbent tests (RAST) were performed. Further, intravesical provocation tests were carried out using IgE RAST-positive antigens, and histamine release assays were performed on the vesical biopsy specimens using anti-IgE antibodies. RESULTS: Five of 6 patients alternately exhibited symptoms of allergic disease and bladder symptoms. The eosinophil and mast cell counts in the vesical biopsy specimens of these 5 patients were increased. Furthermore, an intravesical provocation test performed using the IgE RAST-positive antigen was positive in 4 patients. The mean vesical biopsy specimen histamine release was 17.7% for patients with interstitial cystitis with bronchial asthma which was significantly higher than that for interstitial cystitis patients without bronchial asthma (8.9%) or the control group (4.5%). The prognosis of patients with interstitial cystitis with allergic complications was relatively good. CONCLUSION: Patients with bronchial asthma exhibited hypersensitivity both generally and locally in the bladder. The alternation phenomenon was observed between the hypersensitive organs.
Two hundreds and twenty-six children under five years of age with pneumonia were recruited from an urban poor area in Nairobi, Kenya, and examined for pathogens for 1 year from February 1997. One hundred and twenty-eight of the 226 patients were pathogen-positive cases. The patients under 1-year-old were 61.8% of the pathogen-positive cases. A total 192 organisms were isolated from 128 pathogen-positive patients. Streptococcus pneumoniae had the highest prevalence rate of 31.3%, followed by respiratory syncytial virus with 10.4%, Candida albicans with 9.9%, Moraxella (B) catarrhalis with 7.8%. In S. pneumoniae, 66.7% of the organism was resistant to oxacillin. It was also shown that 51.1% and 65.1% of the S. pneumoniae strains were resistant to gentamicin and trimethoprim/sulfam, respectively. From these results, it is clear that a lot of multi-drug resistant S. pneumoniae strains including penicillin-resistant S. pneumoniae were frequently detected in an urban poor area.
Adhesion of Helicobacter pylori to both human gastric carcinoma cell lines (MKN45, MKN28 and KATO III) and prepared primary human gastric epithelial cells were analyzed with flow-cytometry. All strains adhered to human gastric carcinoma cells. Especially, these strains strongly adhered to MKN45 cells. Adhesion of H. pylori strains to prepared primary human gastric epithelial cells was also observed. However, the adherence rates of H. pylori to these cells were different among the cells used. These results suggested that the host factor might be important for adhesion of the bacteria to human gasgric cells. In addition, H20 monoclonal antibody directed to H. pylori HSP60 inhibited the adhesion of H. pylori to both cells. These results indicate that H. pylori HSP60 might be associated with the adhesion of the bacteria to human gastric epithelial cells.
By an immunomagnetic-bead (IMB) separation technique, isolation of Helicobacter pylori from gastrointestinal and fecal samples of gnotobiotic mice infected with the microorganism was tried. The isolation rate of H. pylori from stomach samples after IMB separation was not higher than that of direct culture of the samples. After IMB separation of feces, H. pylori was detectable by PCR, although H. pylori was not culturable.
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An amino group was introduced to the 3 or 6 position of a pyrazinone ring by cyclization of dipeptidyl chloromethyl ketones. Boc-Tyr-OH was coupled with the amino function, followed by removal of the Boc group to give pyrazinone ring-containing tyrosine derivatives. Of the various tyrosine derivatives prepared, 5-methyl-6-beta-phenethyl-3-tyrosylaminobutyl-2(1H)-pyrazinone exhibited strong binding to the mu-opioid receptor with a Ki value of 55.8 nM and to the delta-opioid receptor with a Ki value of 2165 nM and with a Ki mu/Ki delta value of 0.026.
Human NP220 (hNP220) is a novel DNA-binding nuclear protein, which has an arginine/serine-rich motif and polypyrimidine tract-binding motif, and NP220s and matrin 3 are thought to form a novel family of nuclear proteins. We have determined a chromosomal localization of the cDNA encoding human NP220 to 2p13.1-p13.2 by using fluorescence in situ hybridization. Human matrin 3 cDNA was mapped to chromosomes 1p13.1-p21.1 and 5q31.3, demonstrating that these novel nuclear proteins with similar functions are on different chromosomes.
We have investigated whether niacin-related compounds act as inducers of apoptosis in HL-60 cells. In this study, we found that picolinic acid, dipicolinic acid, and isonicotinamide strongly induce apoptosis. After treatments with these compounds, apoptosis started within 4 h and was induced in about 50% of the cells within 8 h. These compounds induced apoptosis at 5-10 mM, but did not at 1 mM. An ICE-like protease inhibitor (Z-Asp-CH2-DCB) completely blocked the apoptosis, but a caspase-1 inhibitor (Ac-YVAD-CHO) and a caspase-3 inhibitor (Ac-DEVD-CHO) did not block the apoptosis, suggesting that other caspases have the critical roles in the execution process of apoptosis induced by niacin-related compounds.