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Biomedical subjects

M Mitsuhashi

Publications and source records attributed to M Mitsuhashi.

At least 55 records · Page 3Linked to original sources
PubMed1996

Colorimetric ELISA measurement of specific mRNA on immobilized-oligonucleotide-coated microtiter plates by reverse transcription with biotinylated mononucleotides.

In this study, alpha-globin mRNA was captured on plastic plates to which alpha-globin-specific oligonucleotides had been covalently immobilized; the captured mRNA was immediately reverse-transcribed into cDNA in the presence of biotinylated dUTP. Addition of alkaline phosphatase-conjugated streptavidin to react with the biotin was followed by addition of substrate (p-nitrophenyl phosphate), and the resulting colorimetric development was measured at 405 nm. Because multiple biotin molecules are incorporated into cDNA during reverse transcription, and because synthesized cDNA is more stable than mRNA, we could successfully quantify by conventional colorimetry the amount of alpha-globin mRNA on the plate within a linear range of 100 pg to 10 ng. This is more sensitive than conventional Northern blotting. Therefore, the present method may be applicable to measurements of specific mRNAs in various test materials.

Animals↗
PubMed1996

Fluorometric determination of total mRNA with oligo(dT) immobilized on microtiter plates.

We have developed a rapid and nonradioactive method of quantifying cytosolic mRNA from crude cell lysates by using plastic plates to which oligonucleotides containing poly(dT) sequences were previously immobilized. Captured mRNA on the plate was mixed with Yoyo-1 fluorescent indicator dye, and the resulting Yoyo-1 fluorescence of the mRNA-Yoyo-1 complex was measured in a fluorometer. Because Yoyo-1 signals were linearly increased in proportion to the amount of applied mRNA in the range 10-250 ng, the amount of mRNA in test samples can be determined by comparing their Yoyo-1 fluorescence with that of known concentrations of calibrator mRNA. Using this system, we found that the amount of cytosolic mRNA in undifferentiated U937 and HL-60 cells was 268.6 +/- 13.1 and 282.0 +/- 7.8 ng/10(6) cells, respectively, significantly (P < 0.01) more than that of phorbol ester-induced differentiated U937 and HL-60 cells (145.3 +/- 13.9 and 164.7 +/- 11.6), respectively. Therefore, the present system may be applicable to both medical molecular biology research and diagnostics.

Animals↗
PubMed1995

Quantification of mitogen induced human lymphocyte proliferation: comparison of alamarBlue assay to 3H-thymidine incorporation assay.

Proliferation of human lymphocytes in response to various stimuli has traditionally been assessed by measuring uptake of radiolabeled nucleotides such as 3H-thymidine. We have evaluated a fluorometric assay, which uses the commercially available reagent, alamarBlue, as a potential substitute for the 3H-thymidine assay in measuring proliferation of human lymphocytes. In this assay, alamarBlue is added to a population of cells where it is reduced by mitochondrial enzyme activity. The reduced form of the reagent is fluorescent and can be quantitatively detected. The safety and convenience of the alamarBlue assay make it very attractive for use in the clinical laboratory. In this study peripheral blood mononuclear cells (PBMC) from healthy donors were stimulated using the mitogen Concanavalin A, and proliferation was assessed using either the 3H-thymidine or the alamarBlue assay. The alamarBlue assay reliably detects human PBMC and we found that the linear range of detection was 10(4) cells/well (96-well plate) to 5 x 10(5) cells/well. Detection of human PBMC is highly reproducible and the alamarBlue assay may be suitable in a number of applications where detection or relative quantitation of human PBMC is required. The alamarBlue assay also detected mitogen induced proliferation of PBMC although with a significantly lower level of sensitivity than the standard 3H-thymidine assay.

Cell Count↗
PubMed1994

Oligonucleotide probe design--a new approach.

The use of oligonucleotides for gene amplification, as diagnostic probes or antisense-based drugs can be optimized by minimizing the possibility of nonspecific hybridization.

Base Sequence↗
PubMed1994

Epidermal growth factor induces biphasic activation of ornithine decarboxylase in human stomach-derived KATO-III cells.

Effect of epidermal growth factor (EGF) on ornithine decarboxylase (ODC) was examined in human gastric cancer-derived KATO-III cells, because 125I-EGF binding studies indicated a presence of specific binding sites for EGF on these cells. Upon stimulation with EGF, both ODC mRNA expression and ODC enzyme activity were significantly increased in KATO-III cells. However, unlike in other cellular systems, both EGF-induced ODC mRNA expression and ODC enzyme activation were biphasic with the peaks at 15 +/- 10 min and 2.1 +/- 1.5 hrs (mean +/- SE) for mRNA, and 3.1 +/- 1.5 and 7.7 +/- 1.8 hrs (mean +/- SE) for enzyme activity, respectively. Therefore, KATO-III cell line may provide a unique model for the biochemical analysis of EGF action on ODC activation.

Cell Line↗
PubMed1994

Cough variant asthma: a case study with antigen, histamine and methacholine inhalation challenge tests.

This paper presents a 7 year old girl with cough variant asthma, in which house dust challenge test provoked fine crackles on auscultation without any changes of lung function test. Pretreatment with DL-chlorpheniramine maleate for 7 days inhibited the appearance of fine crackles. On histamine inhalation test, fine crackles and rhonchi appeared on auscultation without bronchoconstriction (% fall of one-second forced expiratory volume < 10%). These data suggest that the cause of cough variant asthma is mainly an immunoglobulin E-mediated allergic reaction in the mucus secreting system.

Asthma↗
PubMed1994

Henoch-Schönlein purpura in rheumatoid arthritis.

This is the first report of Henoch-Schönlein purpura associated with permanent joint damage due to rheumatoid arthritis, which was observed in 3 of the 10 adults we treated for Henoch-Schönlein purpura since 1974. Each of 3 women had been admitted with palpable purpura of the lower extremities. The diagnosis was based on various findings including arthralgia, stiffness, and/or swelling of the joints, and on the results of radiographic, immunofluorescence and other studies. Renal biopsy revealed slight mesangial proliferation in 2 of the patients. The nephropathy did not deteriorate following discharge. However, bilateral swelling of the wrists with destructive joint changes was subsequently observed on radiographs in all patients. Since 2 patients showed positivity for human leukocyte antigen DR4, this antigen may have been a genetic factor in the joint disease in these patients.

Adult↗
PubMed1994

[Novel computerized method for designing nucleotide sequence used for DNA probes and PCR primers].

There is no consensus on how to determine optimal sequences of oligonucleotides used as DNA probes and PCR primers, which exhibit high sensitivity with minimum chance of cross-hybridization to other unrelated genes in the target tissues and cells. Here, we propose new strategy for designing oligonucleotide sequence using newly developed computer program, in which candidate oligonucleotides having similar melting temperature (Tm) are extracted from every position of the target gene, then extensive homology analysis is carried out between each candidate oligonucleotide and all the sequences in the user-defined databases using an efficient proprietary algorithm. The new computer program allows researchers to design any probes and primers easily and quickly without having detailed information of the target gene.

Algorithms↗
PubMed1993

Induction of cytochrome P450 1A1 and 1A2 by hyperoxia.

The effect of hyperoxia (O2 > 95%) for 48 hours on the induction of pulmonary and hepatic cytochrome P450 has been investigated in adult male rats. Northern blot analysis using six "specific" oligonucleotide probes indicated that CYP 1A1 and CYP 1A2 mRNAs in liver and CYP 1A1 mRNA in lung were significantly increased by hyperoxic exposure, whereas the major constitutive P450 mRNAs, CYP 2C11 in liver and CYP 2B1 in lung, were decreased. Since induction of CYP 1A1 has only been reported with the use of exogenously administered xenobiotics, further studies were carried out to confirm the results obtained with Northern blot analysis. cDNAs were synthesized for CYP 1A1 and 1A2 in the liver and CYP 1A1 in the lungs and amplified by reverse PCR. These results indicate that these cDNAs were amplified significantly more in the hyperoxia group than in the control animals. Futhermore, CYP 1A1 and 1A2 proteins in liver and CYP 1A1 protein in lungs as well as the corresponding monooxygenase activities were increased by hyperoxia. Hyperoxic induction of CYP 1A1 and 1A2 is the first demonstration of nonexogenous CYP 1A induction in animals and indicates the needs to pursue the changes of Ah receptor-ligand-DNA interaction in hyperoxia.

Animals↗
PubMed1993

Suppression of murine IgE responses with ovalbumin-pullulan conjugates: comparison of the suppressive effect of different conjugation methods and different molecular weights of pullulan.

Ovalbumin (OVA)-pullulan conjugates were made using four different conjugation methods and eight different molecular weights of pullulan ranging from 4,200 to 600,000. Pretreatment of mice by the administration of conjugates made by using cyanulic chloride or cyanogen bromide and pullulan of molecular weight 40,000 or more, anti-OVA IgE antibody response was suppressed completely and anti-OVA IgM and IgG antibody response was enhanced. In contrast, by the administration of conjugates made by using an oxidation or thiol activation method, only partial suppression of anti-OVA IgE antibody response was achieved and no enhancement of anti-OVA IgM and IgG antibody production was observed.

Animals↗
PubMed1992

Activation of mouse macrophages by in vivo and in vitro treatment with a cyanine dye, lumin.

The cyanine photosensitizer, lumin, is a potent macrophage activating agent: 4 days after administration of small amounts of lumin to mice (20-40 ng mouse-1), peritoneal macrophages exhibited a greatly enhanced Fc-mediated ingestion activity; higher doses (more than 3000 ng mouse-1) did not have this effect. The in vitro photodynamic activation of macrophages in mouse peritoneal cells exposed to white fluorescent light (3 J m-2 s-1) was also studied in media containing various concentrations of lumin. A short light exposure (45 J m-2) with 10 ng lumin ml-1 produced a maximum ingestion activity of macrophages. Lumin has absorption peaks at 670 and 760 nm. Therefore we designed experiments in which peritoneal cells were exposed to a red fluorescent light (emission, 660 nm; 0.5 J m-2 s-1). In a medium containing 3 ng lumin ml-1 with 7.5 J m-2 of red light, a markedly enhanced ingestion activity of macrophages was observed. The photodynamic treatment of peritoneal macrophages alone did not stimulate phagocytic activity, but the photodynamic treatment of a mixture of non-adherent (B and T) cells and macrophages resulted in a greatly enhanced ingestion activity of macrophages. Thus non-adherent cells are required for the photodynamic activation of macrophages, implying that an activating factor is generated within the non-adherent cells and transmitted to the macrophages. This hypothesis was confirmed by the observation that co-cultivation of photodynamically treated non-adherent cells with untreated macrophages resulted in a greatly enhanced ingestion capacity.

Animals↗
PubMed1992

Multiple intracellular signaling pathways of the neuropeptide substance P receptor.

The rat substance P (SP) receptor cDNA has been transfected into cultured rat KNRK cells, and a stable cell line expressing functional SP receptors established. Upon stimulation with SP, these cells responded by simultaneously activating two signaling pathways: the mobilization of intracellular Ca2+ and the raising of cyclic adenosine triphosphate (cAMP) levels. Both Ca2+ and cAMP responses were elicited in a similar dose-dependent manner with half maximal concentrations of approximately 5 x 10(-10) M. Following ionomycin treatment SP-dependent Ca2+ responses were abolished, whereas cAMP responses were preserved. Forskolin eliminated the SP-dependent cAMP elevation, however, the SP-induced Ca2+ mobilization remained unchanged. Furthermore, treatment with phorbol esters had no significant effect on either of the two SP-induced responses. Thus it appears that the SP receptor is capable of independently activating Ca2+ mobilization and cAMP pathways. These results may provide new insights for further understanding the diverse activities of SP in various systems in vitro and in vivo.

Animals↗