Chimeric MLL products with a Ras binding cytoplasmic protein AF6 involved in t(6;11) (q27;q23) leukemia localize in the nucleus.

In infantile leukemias and therapy-related leukemias, the MLL gene is frequently found to be disrupted and fused to various translocation partner genes, such as AF4/FEL, LTG9/AF9 and LTG19/ENL as a result of 11q23 translocations. We previously showed that the N-terminal portion common to various chimeric MLL products, as well as to MLL-LTG9 and MLL-LTG19, localizes in the nuclei, and therefore suggested that it might play an important role in leukemogenesis. In the present study, MLL-AF6 chimeric products found in the t(6;11)(q27;q23) translocation were analysed since AF6, a Ras-binding protein, exhibits a different subcellular localization from that of LTG9/AF9 and LTG19/ENL. Immunofluorescence staining data and cell fractionation analyses demonstrated that MLL-AF6 chimeric products localize in the nuclei despite the fact that AF6 itself localizes in the cytoplasm, confirming the importance of the nuclear localization of chimeric MLL products. The region in the N-terminal portion of MLL responsible for this nuclear localization was examined and found to be a region containing AT-hook motifs.

Stool smears for diagnosis of intestinal acute graft-versus-host disease.

A patient with severe diarrhea was successfully diagnosed as having acute intestinal GVHD on stool smear through detection of detached intestinal epithelial cells with apoptosis. Since a stool smear can be easily obtained non-invasively, it is a possible tool for the diagnosis of acute intestinal GVHD.

Identification and characterization of the ackA (acetate kinase A)-pta (phosphotransacetylase) operon and complementation analysis of acetate utilization by an ackA-pta deletion mutant of Escherichia coli.

The pta gene encoding phosphotransacetylase was cloned on a high copy plasmid with or without the ackA gene encoding acetate kinase in Escherichia coli. The acetate kinase and phosphotransacetylase were overproduced in cells harboring the plasmid possessing both genes. Nucleotide sequencing of the pta gene revealed that it is able to produce a polypeptide comprising 714 amino acid residues, which starts at 70 base pairs downstream from the stop codon of the ackA gene. The 77-kDa protein band of overproduced phosphotransacetylase was observed on SDS-polyacrylamide gel electrophoresis, of which the amino terminal sequence corresponds to that of the deduced polypeptide without the amino terminal methionine. Two transcripts of pta of different sizes were found in the cells. A 3,700 nucleotide transcript, which covers the ackA and pta genes, seemed to be produced by the first promoter in the operon and a 2,300 nucleotide transcript, which covers just pta, seemed to be produced by the second promoter. In a synthetic medium containing acetate as the sole carbon source, the growth of an ackA-pta double mutant was greatly impaired. Complementation analyses revealed that both the acetate kinase and phosphotransacetylase were required for the rapid growth in the acetate medium.

HIV infection of megakaryocytic cell lines.

Thrombocytopenia is a common hematologic disorder in HIV infection and occurs in both asymptomatic and AIDS patients. An autoimmune mechanism has been postulated for the platelet destruction associated with some forms of thrombocytopenia. However, recent studies revealed that megakaryocytes are susceptible to HIV infection and suggested the possibility that HIV can directly impair the platelet production from megakaryocytes. This study was designed to characterize the HIV receptor expression in megakaryocytic cells and the responsiveness to HIV infection. Four different megakaryocytic cell lines at different stages of differentiation were established from the peripheral blood of different individuals with hematologic malignancies. CMK and CMY cells (differentiated cell lines) expressed CD4, but CMS and CTS cells (poorly differentiated cell lines) did not. The HIV coreceptor CXCR4 was also expressed in CMY and CMK cells. HIV-1 (HTLV-IIIB) replicated in CMY cells persistently but not in other three cell lines. CMY cells as well as CMK cells were also susceptible to the lytic infection of HIV-2 (LAV2). Pretreatment of the CMY cells with anti-CD4 antibody inhibited the infection by both HIV-1 and HIV-2. Our results indicate that mature megakaryocytic cells express CD4 along with HIV coreceptors and are susceptible to HIV infection.

Expression of MDR-1/P-glycoprotein in childhood acute megakaryoblastic leukemia cells.

Multidrug resistance is a major clinical problem in chemotherapy of malignant disease. Acute megakaryoblastic leukemia (AMKL) is a rare form of childhood leukemia, and is often more resistant to many anticancer chemotherapeutic drugs compared to other types of childhood leukemia. There have been reports of the increased expression in hematologic malignancy of multidrug resistant (mdr-1) gene, which encodes for a transmembrane glycoprotein P-glycoprotein that acts as an efflux pump for structurally unrelated chemotherapeutic drugs. We investigated the malignant cells of 15 newly diagnosed childhood AMKL patients by immunocytochemical analysis and found P-glycoprotein expression in all samples from these patients. RNA prepared from five patients at the time of presentation confirmed the expression of mdr-1 specific message in all cases by Northern blot analysis. These results imply that malignant cells from all childhood AMKL might express the mdr-1/P-glycoprotein.

Expression of multidrug resistant gene (mdr-1/P-glycoprotein) in a megakaryoblastic cell line, CMK, and its enhancement during megakaryocytic differentiation.

Multidrug resistance is a severe clinical problem in the chemotherapy of malignant disease. Acute megakaryoblastic leukemia (AMKL) is a rare form of childhood leukemia, and is often resistant to many anti-cancer chemotherapeutic drugs. Here we report the expression of the mdr-1/P-glycoprotein in a cell line, CMK, established from a patient with AMKL. Expression of mdr-1 mRNA in CMK11-5 cells, a well differentiated subline, was higher than in CMK6 cells, a poorly differentiated subline. The level of P-glycoprotein was also higher in CMK11-5 cells. The cytokines interferon-gamma (IFN-gamma), GM-CSF and IL-3, which were shown to induce megakaryocytic differentiation of CMK cells, enhanced the expression of the mdr-1 mRNA and levels of P-glycoprotein. These results imply that differentiated megakaryocytic cells may have higher levels of the P-glycoprotein expression, suggesting a possible normal physiological function of P-glycoprotein in mature megakaryocytes.

Establishment of a new human megakaryoblastic cell line, CMY, with chromosome 17p abnormalities.

A new megakaryoblastic cell line CMY was established from a Down's syndrome patient suffering from acute megakaryoblastic leukemia. The karyotypes of CMY showed deletion of chromosome 17 or the translocation of 17p, whereas the blasts of the patient did not reveal these abnormalities of chromosome 17 by conventional karyotype analysis. Blasts of the patient failed to respond to chemotherapy and complete remission could not be attained. The abnormalities of 17p became progressively predominant in the patient. These results suggest that the blasts of a minor clone which had the abnormalities of chromosome 17p might have existed in the patient from the beginning and CMY was established from the minor clone. Investigation of p53 gene by PCR-SSCP analysis revealed that blasts of the patient showed normal patterns, while CMY showed an abnormally migrating band in exon 5 alone. This result suggests that another novel oncogenic factor(s) besides p53 might be present on chromosome 17p and other tumor suppresser genes need to be studied.

[The intervention against an outbreak of pulmonary tuberculosis in the dormitory of construction laborers--Connection with approaches from public health, medical treatment, social welfare, and labor management].

An outbreak of pulmonary tuberculosis (TB) in a dormitory of construction laborers took place, and this outbreak was presumed to be caused by the same sourse of infection, based on the results of restriction fragment length polymorphism (RFLP) analysis and other findings. After the first patient was admitted to the hospital with active TB, 18 new other TB patients were discovered by repeated contacts examinations. They were all male and single, and were aged from 41 to 67 years old (mean age 51.7). Among 19 patients, only 4 patients had a health insurance. As these patients lived together in the same dormitory, to prevent infection through close contact in the dormitory, repeated contacts examinations were further performed. In addition, several medical, social, and economical interventions were needed for these patients. It was also required to improve labor conditions in this construction company. It was concluded that comprehensive approaches including public health, medical treatment, social welfare, and labor management aspects were indispensable to prevent TB among relatively poor laborers.

Local current density measurement using a Rogowski probe in Tokyo Spherical Tokamak-2.

A Rogowski probe consisting of a small multi-layer Rogowski coil, five magnetic pick-up coils, and a Langmuir probe was developed to measure the local current density and its direction. It can be moved along the major radius and can be turned around its axis. This probe was used to measure the current density profile near the last closed flux surface of Ohmic plasmas in Tokyo Spherical Tokamak-2. The current density profile was measured successfully with a signal to noise ratio of greater than 20.

Demonstration of improvement in the signal-to-noise ratio of Thomson scattering signal obtained by using a multi-pass optical cavity on the Tokyo Spherical Tokamak-2.

The multi-pass Thomson scattering (TS) scheme enables obtaining many photons by accumulating multiple TS signals. The signal-to-noise ratio (SNR) depends on the accumulation number. In this study, we performed multi-pass TS measurements for ohmically heated plasmas, and the relationship between SNR and the accumulation number was investigated. As a result, improvement of SNR in this experiment indicated similar tendency to that calculated for the background noise dominant situation.

Note: Multi-pass Thomson scattering measurement on the TST-2 spherical tokamak.

In multi-pass Thomson scattering (TS) scheme, a laser pulse makes multiple round trips through the plasma, and the effective laser energy is enhanced, and we can increase the signal-to-noise ratio as a result. We have developed a coaxial optical cavity in which a laser pulse is confined, and we performed TS measurements using the coaxial cavity in tokamak plasmas for the first time. In the optical cavity, the laser energy attenuation was approximately 30% in each round trip, and we achieved a photon number gain of about 3 compared with that obtained in the first round trip. In addition, the temperature measurement accuracy was improved by accumulating the first three round trip waveforms.

Construction of a Bacillus subtilis (natto) with high productivity of vitamin K2 (menaquinone-7) by analog resistance.

To invent a functional natto promoting bone formation, the construction of a strain with high productivity of vitamin K2 (menaquinone-7: MK-7), which is important in the carboxylation of a kind of bone protein participating in bone formation, osteocalcin, was investigated. To screen for a strain appropriate to making natto (a Japanese traditional fermented soybean food) with high productivity of MK-7, a combination of analog resistance to the compounds on the biosynthetic pathway of menaquinones with mutation was done. Consequently, strain OUV23481, with 2-fold higher productivity (1,719 microg/100 g natto) of MK-7 than that of a commercial strain, was constructed as a mutant with analog resistance to 1-hydroxy-2-naphthoic acid (HNA), p-fluoro-D,L-phenylalanine (pFP), m-fluoro-D,L-phenylalanine (mFP), and beta-2-thienylalanine (betaTA). This strain was classified as Bacillus subtilis (natto). The natto made using this strain was evaluated to have a good quality as natto in all the viewpoints of appearance, flavor, taste, texture, and stringiness.

Decreasing accumulation of acetate in a rich medium by Escherichia coli on introduction of genes on a multicopy plasmid.

Escherichia coli excretes acetate during aerobic growth in a rich medium, L-broth containing 0.4% glucose, and growth ceases before depletion of glucose because of the decrease in pH caused by the accumulation of acetate. The addition of sodium phosphate buffer to the medium allows cells to reuse the acetate accumulated. Reuse of the acetate, however, does not occur in the presence of remaining glucose. A gene on a multicopy plasmid was found to significantly decrease the accumulation of acetate by the transformant and the growth did not cease until depletion of both the glucose and acetate in the medium. The gene was tentatively named mlc (making large colonies). The putative Mlc protein has high hology with the NagC protein, which is a regulator protein in the nag operon responsible for the use of N-acetylglucosamine. The nagC gene on a multicopy plasmid also decreased the accumulation of acetate. Although the function of the genes in the phenomenon described is still unclear, transformants harboring the mlc gene or nagC gene on a multicopy plasmid will be useful for condensed cultivations involving glucose.

Intake of fermented soybean (natto) increases circulating vitamin K2 (menaquinone-7) and gamma-carboxylated osteocalcin concentration in normal individuals.

Changes in circulating vitamin K2 (menaquinone-7, MK-7) and gamma-carboxylated osteocalcin concentrations in normal individuals with the intake of fermented soybeans (natto) were investigated. Eight male volunteers were given sequentially fermented soybeans (natto) containing three different contents of MK-7 at an interval of 7 days as follows: regular natto including 775 micrograms/100 g (MK-7 x 1) or reinforced natto containing 1298 micrograms/100 g (MK-7 x 1.5) or 1765 micrograms/100 g (MK-7 x 2). Subsequently, it was found that serum MK-7 and gamma-carboxylated osteocalcin concentrations were significantly elevated following the start of dietary intake of MK-7 (1298 or 1765 micrograms/100 g). Serum undercarboxylated osteocalcin concentrations were significantly decreased by dietary MK-7 (1765 micrograms/100 g) supplementation. Moreover, the changes in serum MK-7 level with the frequency of dietary natto intake were examined in 134 healthy adults (85 men and 39 women) without and with occasional (a few times per month), and frequent (a few times per week) dietary intake of regular natto including MK-7 (775 micrograms/100 g). Serum MK-7 and gamma-carboxylated osteocalcin concentrations in men with the occasional or frequent dietary intake of natto were significantly higher than those without any intake. The present study suggests that intake of fermented soybean (natto) increases serum levels of MK-7 and gamma-carboxylated osteocalcin in normal individuals.

Construction of Pta-Ack pathway deletion mutants of Escherichia coli and characteristic growth profiles of the mutants in a rich medium.

Escherichia coli grown in a rich medium excreted acetate and reused the acetate. Using cloned genes and a plasmid with a temperature-sensitive replication origin, three kinds of Pta-Ack pathway deletion mutants were constructed. Acetate production and reuse by wild-type cells grown in the rich medium was confirmed to largely occur through the Pta-Ack pathway. The deletion mutants of the gene encoding phosphotransacetylase secreted pyruvate before the secretion of acetate into the medium. A deletion mutant of the gene encoding acetate kinase grew at a slow rate, but its secretion and use of acetate were rapid. These results indicated that a pathway(s), other than the Pta-Ack pathway, functions in the control of excess carbon flow in the mutants.

Prolonged intake of fermented soybean (natto) diets containing vitamin K2 (menaquinone-7) prevents bone loss in ovariectomized rats.

The effect of the prolonged intake of dietary vitamin K2 (menaquinone-7, MK-7) on bone loss in ovariectomized (OVX) rats was investigated. OVX rats were freely given experimental diets containing the fermented soybean (natto; including 9.4 micrograms MK-7/100 g diet) without or with supplemental MK-7 (containing 14.1 or 18.8 micrograms of MK-7 as total per 100 g diet) for 150 days. Feeding produced a significant elevation of MK-7 concentration in the serum of OVX rats. In this case, the femoral MK-4 content was significantly increased, but MK-7 was not detected in the femoral tissues, indicating degradation of MK-7. Serum gamma-carboxylated osteocalcin concentration was significantly decreased by OVX. This decrease was significantly prevented by the feeding of the natto diets with supplemental MK-7 (18.8 micrograms/100 g diets). OVX caused a significant decrease in femoral dry weight, femoral calcium content, and mineral density. These decreases were significantly prevented by feeding with diets containing natto with MK-7 (total, 18.8 micrograms/100 g diets). This study demonstrates that the prolonged intake of natto dietary including MK-7 has a preventive effect on bone loss induced by OVX. Dietary MK-7 may be useful in the prevention of osteoporosis.

Interleukin 6, a possible autocrine growth and differentiation factor for the human megakaryocytic cell line, CMK.

CMK is a human cell line derived from a megakaryoblastic leukaemia. It has characteristics of the megakaryocytic lineage, such as the presence of platelet peroxidase, membrane glycoproteins (GP)Ib and GPIIb/IIIa, alpha-granules, and demarcation membranes. The cell line proliferates autonomously in serum-containing medium. Here we report that the cell line expresses the gene for IL-6 and releases small quantities of the cytokine into the medium. Addition of exogenous IL-6 to cultures seeded into medium was found to promote growth of the cells. Conversely, addition of a neutralizing anti-IL-6 antibody inhibited cell growth. These data support the notion that autocrine IL-6 is one of the factors accounting for autonomous growth of the cell line.

Inhibitory effects on HIV-1 protease of constituents from the wood of Xanthoceras sorbifolia.

From a methanolic extract of the wood of Xanthoceras sorbifolia, two new compounds, 29-hydroxy-3-oxotirucalla-7,24-dien-21-oic acid (3, xanthocerasic acid) and epigallocatechin-(4beta-->8, 2beta-->O-7)-epicatechin (6), were isolated, together with 11 known compounds. Of the isolated compounds, 3-oxotirucalla-7, 24-dien-21-oic acid (2), oleanolic acid (4), and 6 were found to be inhibitory substances against human immunodeficiency virus (HIV-1) protease, with their 50% inhibitory concentrations (IC(50)) being 20, 10, and 70 microg/mL, respectively. Condensed tannins of high molecular weights with epicatechin and epiafzelechin as the main extender units were found to be the most active principles of this plant (IC(50) values ca. 6.0 microg/mL).

A novel human leukaemic cell line, CTS, has a t(6;11) chromosomal translocation and characteristics of pluripotent stem cells.

A novel human leukaemic cell line, designated CTS, was established from the peripheral blood of a 13-year-old girl suffering from acute myeloblastic leukaemia (AML) in relapse. CTS cells expressed CD7, CD13, CD33, CD34 and HLA-DR antigens, and showed ultrastructural myeloperoxidase activity. In addition, CTS cells showed DNA rearrangements of the immunoglobulin heavy chain gene and the light kappa chain gene, and deletions of the T-cell receptor delta 1 gene. Cytogenetic analysis revealed a human female diploid karyotype with a t(6;11)(q27;q23) chromosomal translocation. Molecular studies demonstrated a DNA rearrangement of the MLL gene, the expression of a truncated 11.0 kb MLL mRNA and the detection of the MLL/AF-6 fusion transcript in CTS cells. To our knowledge, this cell line is the first report of a human leukaemic cell line with a t(6;11) chromosomal translocation. CTS cells showed no significant proliferative response to the cytokines, IL-2, IL-3, IL-6, IL-11, GM-CSF, G-CSF, EPO, SCF, but were induced to differentiate to the T-cell, B-cell, erythroid or megakaryocytic lineage in the presence of particular cytokines. This CTS cell line may provide a useful tool in the study of the oncogenesis of mixed lineage leukaemia with 11q23 abnormalities and for the analysis of growth and differentiation of pluripotent stem cells.