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Mitsuo Kaku

Publications and source records attributed to Mitsuo Kaku.

At least 19 recordsLinked to original sources
PubMed2003

Regulation of YB-1 gene expression by GATA transcription factors.

GATA-1 is a transcription factor essential for erythroid cell development, and knockdown of GATA-1 gene results in maturation arrest and transformation of erythroblasts. To clarify the mechanism that gives rise to this abnormal phenotype, genes that are aberrantly expressed in the spleen of heterozygous GATA-1 knockdown mutant mouse (referred to as GATA-1 mutant mouse) were identified by using cDNA array. One of these genes, YB-1, was found to be highly expressed in the spleen of GATA-1 mutant mouse. Reporter and electrophoretic mobility shift assays revealed that the proximal GATA element in 5'-UTR region of YB-1 gene functions positively in K562 cells. Furthermore, both GATA-1 and GATA-2, which were transiently expressed in COS-7 cells, bound to this element and activated the YB-1 promoter through this element. These results suggest that YB-1 functions under the regulation of GATA factors in erythroid differentiation and aberrant expression of YB-1 gene may result in dyserythropoiesis.

5' Untranslated Regions↗
PubMed2003

Flow cytometry of GATA transcription factors.

BACKGROUND: Although GATA-1 and GATA-2 have been shown to play an important role in hematopoiesis, the expression levels of these GATA proteins in the targeted cell population of clinical samples have not been studied. We applied flow cytometry (FCM) to examine the expression levels of these GATA proteins in the selected subpopulation in heterogeneous blood cells. METHODS: Cells were treated with a fixing solution and methanol followed by staining with specific antibodies to GATA proteins in a permeabilizing solution. Immunofluorescence microscopy and Northern blot analysis using GATA-1 and GATA-2 transfected cell lines and various leukemic cell lines were used to confirm the specificity of this method. Subsequently, the method was applied in two-parameter studies combining GATA expression with surface marker expression in clinical samples. RESULTS: The positive signals were specifically detected in transfected cells and leukemic cell lines by FCM in agreement with the results of Northern blot and immunofluorescence microscopy. The expression of these GATA factors in the targeted cell population was easily detectable by gating with lineage-specific cell surface markers. When the expression of these GATA proteins was examined in glycophorin A-positive cells in clinical samples, the level of GATA-1 was markedly different among the samples. CONCLUSIONS: This detection system is useful to evaluate the relative expression level of each GATA protein in the targeted cell population among heterogeneous cells, and the results suggest an aberrant expression of GATA factors in hematological diseases.

Animals↗
PubMed2003

High expression of YB-1 gene in erythroid cells in patients with refractory anemia.

It has been shown that aberrant expression of a transcription factor, GATA-1, leads to maturation arrest and transformation of erythroid cells. We previously reported that a multifunctional protein, YB-1, was expressed strongly in the spleen of a GATA-1 mutant mouse, which was filled with transformed erythroblasts. This finding suggested that YB-1 has roles in erythropoiesis. In this study, we examined in vivo expression of YB-1 messenger RNA (mRNA) in bone marrow erythroid cells and erythroid leukemic cell lines. During erythroid differentiation of erythroid leukemic cell lines, the expression level of YB-1 mRNA was highest at the early phase of differentiation and then decreased. In human bone marrow cells, the in vivo expression level of YB-1 mRNA was higher in glycophorin A-positive cells than in glycophorin A-negative cells. An interesting finding was that expression of YB-1 was higher in erythroblasts in myelodysplastic syndrome-refractory anemia (MDS-RA) than in normal cells. The findings suggested that YB-1 functions in the early stage of erythropoiesis and that aberrant expression of this protein may induce hematological diseases such as MDS.

Anemia, Refractory↗
PubMed2003

A simple controlled-rate freezing method without a rate-controlled programmed freezer provides optimal conditions for both large-scale and small-scale cryopreservation of umbilical cord blood cells.

BACKGROUND: Umbilical cord blood (CB) is being used as a source of alternative HPCs for transplantation with increasing frequency. The goal of CB banks for unrelated transplantation is to provide good quality-controlled CB units that can be transplanted for HPCs into the largest possible number of patients. STUDY DESIGN AND METHODS: Large CB samples in freezing bags wrapped with insulators and small samples in cryotubes placed into double styrene-foam boxes were cryopreserved at -85 degrees C without a rate-controlled freezing machine, followed by storage in the liquid phase of nitrogen. After thawing these cells, the viability and recovery of cells, as well as the recovery rate of HPCs such as CD34+ cells, CFU-GM, and total CFU were evaluated. RESULTS: Measurement of the freezing rate in CB bags and cryotubes demonstrated that this simple method for cryopreservation of CB cells provided optimal conditions for both large-scale and small-scale cryopreservation. Recovery of CB progenitor cells after cryopreservation was also shown to be potentially acceptable when evaluated with CD34+ cells, CFU-GM, and total CFU. These results were comparable to the method using a rate-controlled programmed freezer. CONCLUSIONS: A simple method for cryopreservation of CB cells without a rate-controlled programmed freezer could provide a sufficient-enough potential for the transplantability of HPCs after thawing.

Blood Banks↗
PubMed2003

Evaluation of a novel automated chemiluminescent assay system for antimicrobial susceptibility testing.

The newly developed Rapid Lumi Eiken/IS60 (RL/IS60) system automatically determines MICs by detecting chemiluminescence produced in the reaction of a chemiluminescent probe and oxygen metabolites from living microorganisms. The present study evaluated this system for accuracy in antimicrobial susceptibility testing. Chemiluminescence intensities after 4 h of cultivation of clinically important strains were plotted against various concentrations of antimicrobial agents, which resulted in curves reflecting the levels of susceptibility. Sixty-percent inhibitory concentrations based on the susceptibility curves agreed with MICs determined by the reference microdilution method. When the MICs of antimicrobial agents for four quality control (QC) strains (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa) were determined by the RL/IS60 system, most (91.1%) of them were within the QC limits proposed by the National Committee for Clinical Laboratory Standards. The system was further assessed for a total of 162 clinical isolates, including E. coli, Citrobacter freundii, Enterobacter cloacae, Klebsiella pneumoniae, Serratia marcescens, Proteus mirabilis, Morganella morganii, P. aeruginosa, Haemophilus influenzae, S. aureus, coagulase-negative staphylococci, Enterococcus faecalis, Enterococcus faecium, and Streptococcus pneumoniae. Overall, there was 90.6% agreement between the RL/IS60 system and the reference microdilution method. Our results suggest that the RL/IS60 system provides rapid and reliable MICs of a variety of antimicrobial agents for clinical isolates as well as QC strains.

Anti-Bacterial Agents↗
PubMed2003

Efficacy of amikacin combinations for nocardiosis.

We isolated five bacterial strains from patients diagnosed as having nocardiosis. Bacterial species were identified based on the similarities in the nucleotide sequences of 16S ribosomal RNAs. Three of the five strains were identified as Nocardia asteroids, but unexpectedly other two were Streptomyces hygroscopicus and Rothia dentocariosa. The latter two species are not members of the family Nocardiaceae. We investigated the susceptibilities of these five strains to the following nine antimicrobial agents: trimethoprim/sulfamethoxazole (TMP/SMX), minocycline (MINO), erythromycin (EM), amikacin (AMK), cefotaxime (CTX), faropenem (FRPM), imipenem (IPM), ciprofloxacin (CPFX), and sparfloxacin (SPFX). The minimum inhibitory concentration (MIC) ranges (mg/ml) were as follows: TMP-SMX, 4- > 32; MINO, 0.125-8; EM, < or = 0.016- > 32; AMK, 1-2; CTX, 0.063- > 32; FRPM, 0.063-16; IPM, 0.125-2; CPFX, 4-32; and SPFX, 0.5-16. Moreover, the synergistic effects of AMK in combination with each of TMP-SMX, MINO, EM, CTX, IPM, and SPFX were investigated by checkerboard synergy testing. No antagonism was recognized for the three N. asteroides strains. Synergistic and additive effects were observed for the combinations of AMK with CTX, IPM, or SPFX.

Adult↗
PubMed2003

[The Autonomic Nervous Activity in Patients with Essential Hypertension who Showed Early Morning Rise of Blood Pressure].

Autonomic nervous function was evaluated by means of power spectral analysis of heart rate variability in patients with essential hypertension who showed early morning rise of blood pressure (BP). We monitored ambulatory (BP) and physical activity in 80 untreated patients using TM 2425 (A&D Co.Ltd.). Early morning rise of BP was defined a patient's blood pressure obtained between 6:00 to 9:00am is 170mmHg or higher. Patients who showed early morning rise of BP were categorized into groups. Twenty patients, whose mean BP obtained between 6:00 to 9:00am were higher than those obtained between 3:00 to 600am by 30mmHg or more, were defined as a surge type. Sixty patients, in whom the difference in BP was less than 30mmHg, were defined as a sustained type. Power spectral analysis of hourly R-R intervals for 24 hours was performed to obtain the low frequency power (LF, 0.04 to 0.15 Hz) and high frequency power (HF, 0.15 to0.04 Hz). LFn and LF/HF ratio were considered to be indexes of sympathetic nervous activity, and HF parasympathetic nervous activity, respectively. Between 3:00 to 6:00am, LFn and LF/HF were significantly higher and HF was significantly lower in the sustained type patients than in the surge type patients. LF/HF and LFn in the surge type elevated significantly beween 6:00 to 9:00am. These results indicate that both the loss of nocturnal decline in BP in the sustained type and the morning rise in BP in the surge type to occurred in association with changes in autonomic nervous system.

Adult↗
PubMed2003

[New medical education of laboratory medicine at Tohoku University].

The purpose of this paper is to give an insight into the medical education program of our division at Tohoku University. Laboratory medicine in medical education is a field of learned basic clinical tests. Students have to learn the clinical laboratory through early clinical exposure in the first grade and try clinical technology through small-group learning in the fifth grade. Finally, they learn laboratory medicine such as infection control in our or another clinical hospital. The objects of our course are to encourage and promote the highest standards of training and post-graduate education of physicians and scientists at our university.

Clinical Laboratory Techniques↗
PubMed2003

[Activities of antimicrobial agents against 8,474 clinical isolates obtained from 37 medical institutions during 2000 in Japan].

A survey was conducted to determine the antimicrobial activity of fluoroquinolones and other antimicrobial agents against 8,474 clinical isolates obtained from 37 Japanese medical institutions in 2000. A total of 25 antimicrobial agents were used, comprising 4 fluoroquinolones, 13 beta-lactams, minocycline, chloramphenicol, clarithromycin, azithromycin, gentamicin, amikacin, sulfamethoxazole-trimethoprim, and vancomycin. A high resistance rate of over 85% against fluoroquinolones was exhibited by methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium. Isolates showing resistance to fluoroquinolones among methicillin-resistant coagulase-negative Staphylococci, Enterococcus faecalis, and Pseudomonas aeruginosa from UTI accounted for 30-60%. However, many of the common pathogens were still susceptible to fluoroquinolones, such as Streptococcus pneumoniae (including penicillin-resistant isolates), Streptococcus pyogenes, methicillin-susceptible S. aureus (MSSA), methicillin-susceptible coagulase-negative Staphylococci, Moraxella catarrhalis, the Enterobacteriaceae family, and Haemophilus influenzae (including ampicillin-resistant isolates). About 85% of P. aeruginosa isolated from RTI were susceptible to fluoroquinolones. In conclusion, this survey of sensitivity to antimicrobial agents clearly indicated trend for increasing resistance to fluoroquinolones among MRSA, Enterococci, and P. aeruginosa isolated from UTI, although fluoroquinolones are still effective against other organisms and P. aeruginosa from RTI as has been demonstrated in previous studies.

Anti-Bacterial Agents↗
PubMed2002

Aberrant iron accumulation and oxidized status of erythroid-specific delta-aminolevulinate synthase (ALAS2)-deficient definitive erythroblasts.

Alas2 encodes the erythroid-specific delta-aminolevulinate synthase (ALAS2 or ALAS-E), the first enzyme in heme biosynthesis in erythroid cells. Mice with the Alas2-null phenotype showed massive cytoplasmic, but not mitochondrial, iron accumulation in their primitive erythroblasts. Because these animals died by day 11.5 in utero, studies of iron metabolism in definitive erythroblasts were not possible using the in vivo model. In this study, embryonic stem (ES) cells lacking the Alas2 gene were induced to undergo differentiation to the definitive erythroblast stage in culture, and the phenotype of Alas2-null definitive erythroblasts was examined. Alas2-null definitive erythroblasts cell pellets were entirely colorless due to a marked deficiency of heme, although their cell morphology was similar to that of the wild-type erythroblasts. The level of expression of erythroid-specific genes in Alas2-null definitive erythroblasts was also similar to that of the wild-type erythroblasts. These findings indicate that Alas2-null definitive erythroblasts developed to a stage similar to that of the wild-type erythroblasts, which were also shown to be very similar to the bone marrow erythroblasts in vivo. In contrast, Alas2-null definitive erythroblasts contained 15 times more nonheme iron than did the wild-type erythroblasts, and electron microscopy found this iron to be distributed in the cytoplasm but not in mitochondria. Consistent with the aberrant increase in iron, Alas2-null definitive erythroblasts were more peroxidized than wild-type erythroblasts. These findings suggest that ALAS2 deficiency itself does not interfere with the development of definitive erythroid cells, but it results in a profound iron accumulation and a peroxidized state in erythroblasts.

5-Aminolevulinate Synthetase↗
PubMed2002

Primary marginal zone lymphoma of the thymus accompanied by chromosomal anomaly 46,X,dup(X)(p11p22).

We report a case of primary marginal zone lymphoma in the thymus of a 34-year-old woman. She was initially suspected of having a mediastinal plasmacytoma because of the presence of dominantly proliferating plasmacytic cells in a small fragment obtained by thoracoscopic biopsy, and an elevated level of serum monoclonal IgA. However, histology of the tissue obtained by a subsequent open surgical biopsy revealed diffuse proliferation of atypical monocytoid B-lymphocyte-like cells, which showed prominent plasmacytic differentiation and a close association with thymic epithelial cells consistent with the histology of a marginal zone lymphoma of the thymus. These lymphoma cells were positive for CD19, CD20, IgA, and kappa, and negative for CD5, CD10, and other T/NK-cell and myelomonocyte antigens. Both G-banded and spectral karyotyping analyses revealed the lymphoma cells carried a chromosomal anomaly, 46,X,dup(X)(p11p22). Although large cell type B-cell lymphoma in the thymus (mediastinal diffuse large B-cell lymphoma), which is categorized as a definite subtype in revised European-American classification of lymphoid neoplasms and the new World Health Organization classification, is not infrequent, primary marginal zone lymphoma of the thymus is extremely rare. To our knowledge, this is the first case report of primary marginal zone lymphoma of the thymus with a detailed chromosomal analysis.

Adult↗
PubMed2002

Chemically modified ribozyme targeting TNF-alpha mRNA regulates TNF-alpha and IL-6 synthesis in synovial fibroblasts of patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is chronic polyarthritis in which a variety of inflammatory cytokines play a role. Since tumor necrosis factor-alpha (TNF-alpha) is one of the most important cytokines in the pathogenesis of RA, we evaluated the feasibility of ribozymes as a therapeutic agent to control the inflammatory process of RA synovium. A hammerhead ribozyme against TNF-alpha was chemically modified to increase nuclease resistance and added to RA fibroblastlike cell cultures without using a delivery system. The cellular uptake of fluorescent-labeled ribozyme into synovial cells was found to last at least 48 hr by confocal laser scanning microscopy. The ribozyme targeting TNF-alpha gene inhibited both the expression of TNF-alpha mRNA and the secretion of TNF-alpha and IL-6. The cytotoxic effect by the ribozyme on synovial cells was negligible when determined by an alamar blue assay. Chemically modified ribozymes designed to suppress the TNF-alpha gene may be potential as a therapeutic agent for rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed2002

Human leukocyte antigen-DR expression on peripheral monocytes as a predictive marker of sepsis during acute pancreatitis.

INTRODUCTION: The mortality associated with severe acute pancreatitis is still high, and death in the later stage of the disease is chiefly due to bacterial infection and sepsis. However, objective parameters for the risk of sepsis in acute pancreatitis have not been established. AIM: To investigate the value of human leukocyte antigen-DR (HLA-DR) on peripheral monocytes for predicting the development of sepsis during acute pancreatitis. METHODOLOGY: The expression of HLA-DR on peripheral monocytes was measured in 64 patients by flow cytometry at admission and 7 and 14 days after the onset of acute pancreatitis. Twenty-eight patients with severe acute pancreatitis and 36 with mild acute pancreatitis, as determined by the Atlanta classification, were enrolled. RESULTS: Six patients had sepsis, and two of them died during the hospital stay. At admission, the percentage of HLA-DR-expressing cells in the monocyte population was significantly lower in the patients who had sepsis in the later course than in the patients who did not have sepsis. A percentage lower than 80% at admission was observed in 17 patients, and the patients who had persistently low percentages of HLA-DR-expressing monocytes throughout the observation period had sepsis in the later clinical course, whereas the patients in whom expression recovered to the normal range were spared the development of sepsis. CONCLUSION: In acute pancreatitis, the low percentage of HLA-DR-expressing cells in the monocyte population is a reliable predictor of the development of sepsis. Monitoring of monocyte HLA-DR expression may be a useful marker for identifying the patients who are at high risk of sepsis in acute pancreatitis.

Acute Disease↗
PubMed2002

Regulation of tumor necrosis factor alpha promoter by human parvovirus B19 NS1 through activation of AP-1 and AP-2.

Human parvovirus B19 frequently causes acute and chronic arthritis in adults. The molecular mechanism of B19 arthritis, however, remains poorly understood. We previously showed that the transmission of B19 from rheumatoid synoviocytes to monocytic cells is associated with enhanced secretion of tumor necrosis factor alpha (TNF-alpha), which triggers inflammation, and interleukin-6. To determine the role of B19 in the production of TNF-alpha, we focused on the function of its nonstructural protein, NS1, and established monocytic U937 lines transduced with the NS1 gene under the control of an inducible promoter. Production of TNF-alpha mRNA and protein was elevated in a manner associated with NS1 expression. Reporter assays revealed that AP-1 and AP-2 motifs on the TNF-alpha promoter were responsible for NS1-mediated up-regulation. Electrophoretic mobility shift assay showed specific binding of nuclear proteins from NS1 gene-transduced cells with the AP-1 or AP-2 probe. Antibodies against transcription factors AP-1 and AP-2 and anti-NS1 antibody inhibited the binding of nuclear proteins to the corresponding probes. These data indicate that NS1 up-regulates TNF-alpha transcription via activation of AP-1 and AP-2 in monocytic cells. The molecular mechanisms of NS1-mediated TNF-alpha expression would explain the pathogenesis of B19-associated inflammation.

DNA-Binding Proteins↗
PubMed2002

Delayed recovery of effector memory CD4+ T cells by highly active antiretroviral therapy in a patient with HIV-1 infection.

Effector memory T cells, which are potentially important in the protection against various pathogens, have been shown to be CCR7 negative. We report a case with HIV-1 infection in whom the change in the cell numbers of the subsets of CD4+ T cells, including CCR7 negative memory CD4 + T cells, in peripheral blood was monitored for more than one year after the initiation of highly active antiretroviral therapy. Percentage of each subsets in lymphocytes was measured by triple staining on lymphocyte fraction in flow-cytometry. The numbers of total CD4+ T cell, naive T cells, and CCR7 positive memory T cells successfully increased within half a month after the initiation of the therapy. Instead, the recovery of the cell number in CCR7 negative memory T cells delayed, and continued to increase untill 10 months after the initiation of the therapy. It suggests the possibility of delay in recovery of immune systems after the initiation of the therapy in HIV-1-infected patients, despite the prompt recovery of total CD4 + T cells.

Adult↗
PubMed2002

[A case of disseminated tuberculosis requiring extended period for the identification of Mycobacterium tuberculosis on culture].

A 80-year-old male visited an outpatient department of a nearby hospital complaining of fever, cough, and poor appetite on June 2000. The patient was diagnosed as bacterial pneumonia and was treated with antibiotics although specific cause could not be identified. After one month, he was hospitalized due to lack of improvement. After admission, acid-fast bacilli (AFB) was found from the bronchial washing. The patient was then transferred to our hospital. Upon admission, sputum smear examination was positive for AFB and MTB was confirmed by PCR. Therapy was initiated with INH 300 mg, RFP 450 mg, EB 1000 mg, and PZA 1000 mg, orally daily. However, on the day following the admission, he became unconscious. Brain MRI showed several small granulomas on the cortex of the bilateral anterior and temporal brain. Although AFB was not detected from the cerebrospinal fluid, tuberculous meningitis was suspected and steroid was given. Nine days after admission, the patient died due to tuberculous meningitis. The isolation of MTB had been attempted on Ogawa culture medium using patient's sputum and liquor, and it took 14 weeks to find colony growth both from sputum and liquor. In the autopsy, numerous granulomas were detected in his lung, liver, kidney, and pancreas. These findings indicate that disseminated growth of MTB occurred in vivo in spite of very slow growth of MTB in vitro.

Aged↗
PubMed2002

[Relationship of polymorphism in CYP2C9 to genetic susceptibility to diclofenac-induced influenza-virus-associated encephalopathy].

The mechanism causing influenza-virus-associated encephalopathy is unclear, even though diclofenac metabolites may induce this pathogenesis. CYP2C9 is known as the major cytochrome P450 gene product that catalyzes diclofenac in human liver. It is uncertain whether the mutation of CYP2C9 is associated the pharmacologic effects of diclofenac in influenza infection. Therefore, we applied a simple and rapid procedure involving real-time fluorescence allele-specific PCR(TaqMan-ASA) assay and denaturing HPLC assay to detect the mutation of CYP2C9 gene. A single-base mutation in the CYP2C9 gene was found in one of thirty subjects in the healthy population. We suggest that this mutation in the CYP2C9 gene may be related to diclofenac-induced influenza-virus-associated encephalopathy.

Aryl Hydrocarbon Hydroxylases↗