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Biomedical subjects

M Masuko

Publications and source records attributed to M Masuko.

34 records · Page 2Linked to original sources

Profile of cell cycle in hematopoietic malignancy by DNA/RNA quantitation using 7AAD/PY.

Using 7-amino-actinomycin-D/pyronin Y (7AAD/PY), we analyzed the surface phenotypes and cell cycle of 22 hematopoietic cell lines based on their cellular DNA/RNA content. Populations of G1a, G1b, S, and G2M, the DNA index (DI), and the RNA index of S phase (SRI) were calculated by means of DNA/RNA dot plots. Two new parameters were extracted from the cell-cycle profiles: the nucleic acid index of S phase (NI) and the coefficient of variations in the RNA at S phase (SVC). DNA/RNA dot plots of cell lines revealed four characteristic profiles of the cell cycle, defined with the calculated NI and SCV. These were type 0 (small NI, large SCV), type I (small NI, small SCV), type II (large NI, small SCV), and type III (large NI, large SCV). Type O included four stem cell lines: one t(1;19) leukemia, two Ph1+ acute lymphocytic leukemia (ALL), and one biphenotypic crisis of chronic granulocytic leukemia (CGL). Type I included five ALL cell lines: three T-ALL and two common B-ALL. Type II contained 10 myeloid cell lines: five AML and five myeloid crisis of CGL. Type III contained three relatively immature lymphoma cell lines: two Burkitt's lymphoma and one follicular center lymphoma. Calculated NI/SCV (%) were as follows: type 0, 2.27 +/- 0.19/16.7 +/- 3.7; type I, 2.20 +/- 0.30/11.1 +/- 0.7; type II, 3.64 +/- 0.52/11.8 +/- 1.0; and type III, 3.60 +/- 0.53/17.5 +/- 1.9. Cell-cycle analysis of blasts using 7AAD/PY combined with surface phenotyping may yield important information for classifying hematopoietic malignancy within 2 hours of patient admission.

Antigens, CD↗

Nucleic acid hybridization accompanied with excimer formation from two pyrene-labeled probes.

We developed a novel nucleic acid hybridization method based on excimer formation. We used two different 16-mer oligonucleotide probes that had a combined continuous-sequence run that was complementary to a target 32-mer. Prior to hybridization, the adjacent terminal ends (i.e. the 3'-terminal of one probe and the 5'-terminal of the other probe) were each labeled with one pyrene residue. When these probes simultaneously hybridized to the target, a 495 nm broad fluorescence band was produced. The intensity of this band increased as the intensity of the pyrene monomer bands decreased, indicating that the 495 nm band was attributed to the pyrene excimer. The excimer fluorescence, easily differentiated from the monomer bands for emission wavelength, opens up a new way to perform homogeneous hybridization assays and in vivo imaging of nucleic acids.

Base Sequence↗

Real-time analysis of the transcriptional regulation of HIV and hCMV promoters in single mammalian cells.

The regulation of human cytomegalovirus (hCMV) and human immunodeficiency virus (HIV) gene expression has been studied in single intact mammalian cells. Viral promoters were placed upstream of the firefly luciferase reporter gene and the resulting hybrid reporter constructs were stably integrated into the HeLa cell genome. A highly sensitive photon-counting camera system was used to study the level of gene expression in single intact cells. Luciferase expression was studied in the absence of activators of viral gene expression, in the presence of the HIV-1 TAT transactivator protein, or in the presence of sodium butyrate, a non-viral activator of gene expression. In the absence of any activator of gene expression, while expression was undetectable in most cells, significant levels of basal luciferase activity were observed in a few cells, indicating heterogeneity in gene expression in the cell population. In the presence of the general activator of viral gene expression, sodium butyrate, transcriptional activation from the viral promoters gave rise to significant and relatively homogeneous levels of luciferase expression in a majority of cells. The luciferase imaging technology was used for the real-time analysis of changes of gene expression within a single cell. This non-invasive reporter assay should become important for studies of the temporal regulation of gene expression in single cells.

Animals↗

Excimer formation by hybridization using two pyrene-labeled oligonucleotide probes.

Pyrene excimer formation was achieved in an aqueous solution by nucleic acid hybridization. We used two different 16-mer oligonucleotide probes which had a combined continuous-sequence run complimentary to a target 32-mer. Prior to hybridization, the adjacent terminal ends (i.e., the 3'-terminal of one probe and the 5'-terminal of the other probe) were each labeled with one pyrene residue. The simultaneous hybridization of the probes to the target induced a 495-nm broad fluorescence band characteristic for pyrene excimer. Temperature and molecular configurations of the hybrid influenced the excimer formation.

Base Sequence↗

Rapid detection and counting of single bacteria in a wide field using a photon-counting TV camera.

Using Escherichia coli as a model bacterium, we tested a photon-counting method for enumeration of bacteria. This method is based on the principle that microscopic sized luminous particles in a wide field can be directly detected and counted using a photon-counting TV camera without the use of a microscope. E. coli cells were labeled with peroxidase and luminescence induced by adding a luminol-based reaction mixture. The number of luminous spots in the TV images was in good agreement with the number of bacterial colonies grown from labeled cells. The results show that our method provides a rapid and easy microbial counting system for such purposes as clinical diagnosis, microbial analysis in food, and environmental assessment.

Bacteriological Techniques↗

A novel method for detection and counting of single bacteria in a wide field using an ultra-high-sensitivity TV camera without a microscope.

We describe a novel method for enumeration of bacteria, based on the principle that small, light emitting particles on a flat surface can be easily and rapidly detected and counted using an ultra-high-sensitivity TV camera. To test this method, we obtained TV images of individual cells of a luminous bacterium on a membrane filter without the use of a microscope. The positions of the luminous points in the TV images were almost the same as the positions of the bacterial colonies after growth. Our results show that the single cells can be efficiently detected and counted by our method if they emit light or can be stimulated to emit light.

Colony Count, Microbial↗

Glucose reduces PDGF production and cell proliferation of cultured vascular endothelial cells.

The effect of glucose on PDGF production and cell proliferation was studied on cultured bovine aortic endothelial cells. PDGF levels were measured using an enzyme-linked immunosorbent assay technique newly developed in our laboratory. The cell proliferation rate was determine on the basis of 3H-thymidine incorporation into cellular DNA. PDGF levels in culture medium were below the detection limit of the assay. However, PDGF levels were measurable in cultured endothelial cells at confluence. Both PDGF production and thymidine incorporation were significantly reduced in the endothelial cells cultured with high concentrations of glucose. These results suggest that reduced PDGF production and cell proliferation may be involved in altered vascular endothelial function in diabetics.

Animals↗

[Treatment of eustachian tube using a remodelled fiberscope conformed to the anatomical variety of its orifice].

The structure of the opening of the Eustachian tube of 702 cases were observed with fiberoptic endoscope, and the relationship between the difficulty in ear douche by Eustachian tube catheterization and the shape of the orifice was discussed. The shape of pharyngeal orifice of the tube was classified into two types. The one which is well-known as ordinary shaped was named as type I, while the other which has an arched upper edge by torus tubarius was termed as type II. Type II orifices were found more frequently (54.3%) than type I. Insertion of a catheter was difficult in type II ones because the tip of catheters was apt to slip down from the tubal elevation. Moreover, anatomical irregularities in the nasopharynx, which is observed quite often, seem to be a factor of difficulties in douching the tube. In case of a failure in ear douches, it is necessary for us to detect its cause, and in case of type II orifice, the way of probing the orifice should be changed. I have treated some patients who were suffered from tubal obstruction with an injection of remedies into the auditory tubes, observing with remodelled Olympus NPF-S3 fiberscope, and have got a good result.

Adolescent↗

Spectroscopic evidence for a copper-nitrosyl intermediate in nitrite reduction by blue copper-containing nitrite reductase.

The reactions of nitrogen monoxide (NO) with the blue copper-containing nitrite reductases from Alcaligenes sp. NCIB 11015 and Achromobacter cycloclastes IAM 1013 were investigated spectroscopically. The electron paramagnetic resonance (EPR) signals of the blue coppers vanished in the presence of NO at 77 K, being fully restored by the removal of NO. The additions of NO to the enzyme solutions resulted in the substantial bleaching of the visible absorption bands at room temperature. The reactions were also completely reversible. These results suggest the formation of a cuprous nitrosyl complex (Cu+-NO+), which is likely the intermediate in the enzymatic nitrite reduction.

Alcaligenes↗

Identification of heme axial ligands of cytochrome c' from Alcaligenes sp. N.C.I.B. 11015.

The spectral properties of both ferric and ferrous cytochromes c' from Alcaligenes sp. N.C.I.B. 11015 are reported. The EPR spectra at 77 K and the electronic, resonance Raman, CD and MCD spectra at room temperature have been compared with those of the other cytochromes c' and various hemoproteins. In the ferrous form, all the spectral results at physiological pH strongly indicated that the heme iron(II) is in a high-spin state. In the ferric form, the EPR and electronic absorption spectra were markedly dependent upon pH. EPR and electronic spectral results suggested that the ground state of heme iron(III) at physiological pH consists of a quantum mechanical admixture of an intermediate-spin and a high-spin state. Under highly alkaline conditions, identification of the axial ligands of heme iron(III) was attempted by crystal field analysis of the low-spin EPR g values. Upon the addition of sodium dodecyl sulfate to ferric and ferrous cytochrome c', the low-spin type spectra were induced. The heme environment of this low-spin species is also discussed.

Alcaligenes↗

Effects of freezing on purified nitrite reductase from a denitrifier, Alcaligenes sp. NCIB 11015.

The effects of freezing on Alcaligenes sp. nitrite reductase [nitric-oxide: ferricytochrome c oxidoreductase, EC 1.7.2.1] dissolved in sodium phosphate (pH 7.2) were investigated. The nitrite reductase was gradually activated with time in the frozen state, resulting in an increase in its activity of 2.5-4.5 times. The final freezing temperature influenced the enzyme activation, maximal activation being observed at around -20 degrees C. All the enzymatic activities that the nitrite reductase is known to catalyze were enhanced by freeze-thawing. The activation was followed by neither association-dissociation nor any gross conformational change of the enzyme molecule, but was accompanied by an increase in the fluorescence intensity of 2-p-toluidinonaphthalene-6-sulfonate used as a hydrophobic probe. The results are consistent with the hypothesis that the activation of the NiR is due to a limited conformational change of the enzyme molecule, particularly in the hydrophobic region. The mechanism of the activation of NiR by freeze-thawing is discussed, in comparison with the mechanisms of inactivation by freeze-thawing of many enzymes reported by previous workers.

Alcaligenes↗

Characterization of nitrite reductase from a denitrifier, Alcaligenes sp. NCIB 11015. A novel copper protein.

A copper-containing dissimilatory nitrite reductase [nitric-oxide: ferricytochrome c oxidoreductase, EC 1.7.2.1] was purified from a denitrifier, Alcaligenes sp. NCIB 11015, by ion-exchange chromatography on CM-cellulose, gel filtration on Sephadex G-150, and adsorption on hydroxyapatite. The preparation was homogeneous by SDS-polyacrylamide gel electrophoretic criteria, and its enzymatic activity increased considerably by freezing (at -20 degrees C) and thawing. The enzyme consists of two subunits with a molecular weight of 37,000, and the isoelectric point and redox potential are 8.4 and +260 mV (pH 7.2), respectively. The EPR spectrum and copper analysis clearly indicated that the enzyme contains two type I copper atoms per molecule but no other types of copper. This is the first blue copper protein that exhibits catalytic activity despite possessing only type I copper.

Alcaligenes↗

Effects of transfection of p210bcr-abl and bcr-v-abl into the factor-dependent human leukemia cell line HSM-911.

In order to clarify the action of the bcr-abl, a growth factor dependent human leukemic cell line (HSM-911) was transfected with p210bcr-abl or bcr-v-abl by electroporation. The cells transfected with bcr-v-abl, but not the cells transfected with p210bcr-abl, became growth factor independent. Some clones of the cells transfected with p210bcr-abl demonstrated cellular maturation (nuclear segmentation, becoming positive for naphthol ASD chloroacetate esterase, the disappearance of CD34 expression and the appearance of glycophorin A and CD10 expression). Moreover, these clones transfected with p210bcr-abl demonstrated apoptosis (increased expression of Fas and DNA ladder formation suggesting apoptotic DNA fragmentation). These findings demonstrated the different actions of p210 bcr-abl and bcr-v-abl, the former of which gave the cells the characteristics of maturation like the cells from chronic myelogenous leukemia, and the latter of which rendered the cells grow autonomously.

Apoptosis↗