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Biomedical subjects

R Miki

Publications and source records attributed to R Miki.

12 recordsLinked to original sources
PubMed2001

Delineating developmental and metabolic pathways in vivo by expression profiling using the RIKEN set of 18,816 full-length enriched mouse cDNA arrays.

We have systematically characterized gene expression patterns in 49 adult and embryonic mouse tissues by using cDNA microarrays with 18,816 mouse cDNAs. Cluster analysis defined sets of genes that were expressed ubiquitously or in similar groups of tissues such as digestive organs and muscle. Clustering of expression profiles was observed in embryonic brain, postnatal cerebellum, and adult olfactory bulb, reflecting similarities in neurogenesis and remodeling. Finally, clustering genes coding for known enzymes into 78 metabolic pathways revealed a surprising coordination of expression within each pathway among different tissues. On the other hand, a more detailed examination of glycolysis revealed tissue-specific differences in profiles of key regulatory enzymes. Thus, by surveying global gene expression by using microarrays with a large number of elements, we provide insights into the commonality and diversity of pathways responsible for the development and maintenance of the mammalian body plan.

Animals↗
PubMed2001

Preprocessing implementation for microarray (PRIM): an efficient method for processing cDNA microarray data.

cDNA microarray technology is useful for systematically analyzing the expression profiles of thousands of genes at once. Although many useful results inferred by using this technology and a hierarchical clustering method for statistical analysis have been confirmed using other methods, there are still questions about the reproducibility of the data. We have therefore developed a data processing method that very efficiently extracts reproducible data from the result of duplicate experiments. It is designed to automatically filter the raw results obtained from cDNA microarray image-analysis software. We optimize the threshold value for filtering the data by using the product of N and R, where N is the ratio of the number of spots that passed the filtering vs. the total number of spots, and R is the correlation coefficient for results obtained in the duplicate experiments. Using this method to process mouse tissue expression profile data that contain 1,881,600 points of analysis, we obtained clustered results more reasonable than those obtained using previously reported filtering methods.

Animals↗
PubMed1998

Cloning of rabbit TR4 and its bone cell-specific activity to suppress estrogen receptor-mediated transactivation.

To clone a new nuclear receptor, we screened a rabbit heart complementary DNA (cDNA) library with degenerate oligonucleotide probes corresponding to the DNA-binding domain of nuclear receptors, which is highly conserved among receptors. One of the cDNA clones, clone 23, encodes a novel protein of 596 amino acids, and predicted molecular mass is 66 kDa. Homology search analysis identified this protein as rabbit TR4 (TR4-0). We also cloned the cDNA encoding a rabbit TR4 isoform (TR4-1), which lacks the putative C-terminal ligand-binding domain (350 amino acids) caused by a 23-bp exon deletion, which probably occurred during messenger RNA (mRNA) splicing. Northern blot analysis showed that TR4s are expressed with two kinds of mRNAs (9.0 kb and 2.8 kb), both of which are relatively abundant in brain, testis, and bone. RT-PCR analysis, using pairs of primers specific for each TR4, showed that both types of receptor express in various tissues. Furthermore, both are present in primary osteoblasts and bone marrow cells, though the mRNA levels of TR4-0 were much higher than those of TR4-1. A functional study, using a transient transfection assay, showed that both receptors suppressed retinoid X receptor (RXR)-retinoid acid receptor, RXR-TR, and RXR-VDR-mediated transactivation significantly in COS-1 and osteosarcoma cells (UMR-106, ROS17/2.8) and that TR4-0 was much more effective than TR4-1. Unexpectedly, we found that the TR4s effectively suppressed estrogen receptor-mediated transactivation in bone cells, but neither in kidney (COS-1) nor breast cancer cells (MCF-7, one of the major target cells of the estrogen action). Thus, the present study shows a novel property of the TR4 orphan receptor, acting as a bone cell-specific repressor in the estrogen receptor-mediated signaling pathway.

Amino Acid Sequence↗
PubMed1995

Gene expression of retinoic acid receptors, retinoid-X receptors, and cellular retinol-binding protein I in bone and its regulation by vitamin A.

We investigated the gene expression of retinoic acid (RA) receptors (RARs) and retinoid-binding proteins, and the effect of vitamin A on gene expression in the rat tibia to understand the actions of vitamin A on bone tissue. The transcripts of all three subtypes of all-trans RAR (alpha, beta, and gamma) and two of three subtypes of retinoid-X receptor (alpha and beta) were detected by Northern blotting. Among cellular retinol-binding protein I (CRBP-I) and CRBP-II and cellular retinoic acid-binding protein I and II, only the CRBP-I gene was expressed. These results indicated that in bone, the actions of vitamin A are exerted through these nuclear receptors by regulating target gene expression, and through CRBP-I by modulating the intracellular transport of vitamin A. Moreover, using rats of various retinoid status, we investigated whether the expression of target genes for vitamin A (RAR beta and CRBP-I) is regulated by retinoic acid (RA) in the adult rat tibia. The messenger RNA levels of these genes in vitamin A-deficient rats decreased to half of those in normal rats and were quickly restored (4 h) by either all-trans-RA or 9-cis-RA. Excess RA given to normal rats doubled the messenger RNA levels of these two genes. These results verified that, like other target tissues, bone is a target for vitamin A in terms of gene expression. In addition, we examined the effect of RAs on the expression of the target genes for vitamin D, because it is possible that 9-cis-RA is involved in the transcriptional control of vitamin D receptor by forming a heterodimer complex with retinoid-X receptor. The vitamin D-regulated osteopontin gene was induced 4 h after the administration of RA regardless of retinoid or vitamin D status. RA also induced osteopontin gene expression in concert with vitamin D in normal rats. Specific inhibitors of transcription showed that gene expression may be regulated by RA at the transcriptional level. Thus, the results presented here clarified at the molecular level that bone is a target organ for vitamin A in terms of gene expression.

Animals↗
PubMed1993

Chronic melioidosis: a report of the first case in Japan.

A 41-year-old Japanese male with uncontrolled diabetes mellitus and alcoholic liver dysfunction developed melioidosis after his business trip to Indonesia and Singapore in 1988. His disease started with spiked fever on the following day after extraction of a tooth, and a liver abscess developed, followed by abscesses in the spleen and in the subphrenic space. In spite of splenectomy and intensive antimicrobial treatments for three months, he developed parotitis, prostatitis, and abscess of the right submandibular gland at 5 to 16-month interval. Pseudomonas pseudomallei was isolated from the blood and pus from each abscess. The lung was not involved. At present, he has returned to work, with continued intravenous instillation of imipenem/cilastatin.

Adult↗
PubMed1993

[Detection and identification of mycobacterial DNA with sputa and AIDS samples by nested-polymerase chain reaction (nested-PCR)].

We have demonstrated the nested-polymerase chain reaction (nested-PCR) assay detected from 14 mycobacterial species. We have further demonstrated the species specific restriction sites within amplified dnaJ gene, which allowed us to differentiate the mycobacterial DNA by combination of the PCR with the restriction fragment length polymorphism (PCR-RFLP). Nested-PCR-RFLP was used to detect and identified mycobacterial DNA in the sputa samples and HIV related samples. The target DNA was a 196-base pair segment of dnaJ gene. Of 68 sputum samples tested, 7 were smear positive for acid-fast bacilli and culture. The 7 samples were also identified with Mycobacterium tuberculosis by PCR-RFLP. We tested 69 HIV related samples (19 frozen samples, 22 paraffin embedded samples and 28 lymphocyte from HIV infected people). Of 38 samples were positive for nested-PCR, 8 M. tuberculosis complex, 7 M. avium, 8 M. intracellulare, and 16 others were detected by PCR-RFLP. The PCR method is useful for the rapid diagnosis of mycobacterial infection.

AIDS-Related Opportunistic Infections↗
PubMed1992

[Detection of mycobacteria by DNA amplification].

Polymerase Chain Reaction (PCR) was used to detect and to identify Mycobacterium species. In this study, 13 out of 14 Mycobacterium species were detected by using six pairs of oligonucleotide primers. The PCR product was detected by non-isotopic southern blot hybridization even when as little as 10 fg of purified M. tuberculosis DNA was used. And 8 mycobacterial species were identified by PCR-Restriction Fragment Length Polymorphism (RFLP) using two kinds of endonuclease.

Base Sequence↗
PubMed1990

[Zygomycosis caused by Cunninghamella bertholletiae].

Cunninghamella bertholletiae, an uncommon cause of human fungal infection, has been reported with increasing frequency in recent years in Western countries. We report a case of acute myelogenous leukemia terminated by an uncommon complication of zygomycosis caused by C. bertholletiae, which seems to be the first human case reported in Japan. In this case, the fungus disseminated many organs, including the thyroid gland.

Adult↗
PubMed1989

[Dosimetry of fast neutrons in 1W nuclear reactor with plastic nuclear-track detectors].

A nuclear reactor at Kinki University is operated at the maximum of 1W. It produces fission neutrons as much as gamma-rays. To facilitate its use for neutron radiobiology, fast neutrons inside the reactor were measured with nuclear-track detectors TS 16 N and a pair of ion chambers. The angular dependence of TS 16 N response, an anisotropy of fast neutron fluxes in the reactor and misuse of the kerma factor assumed for radiation protection business are the major causes of discrepancy is measured doses by the two methods. Correction factors for the three causes are proposed. After correction, neutron doses estimated with TS 16 N and chambers agree within 5%. The dose-rate at the reactor's center is about 20 tissue-cGy/h. This is the first in situ dosimetry of fast neutrons in a reactor with track detectors attached to biologic samples. Our routine usage has demonstrated that, if used with caution, TS 16 N elements are handy, reliable monitors for fast neutron dosimetry as they are insensitive to contaminated gamma-rays and small enough to be attached to biologic samples.

Fast Neutrons↗