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Search Results: 1 - 10 of 685 matches for " Tetsuji Nagata "
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Studies on mitochondrial macromolecular syntheses in various organs of aging animals labeled with 3H-precursors as revealed by electron microscopic radioautography  [PDF]
Tetsuji Nagata
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.14034
Abstract: In order to study the aging changes of intramitochondrial macromolecular synthesis in various organs of aging animals during the development and aging, 10 groups of developing and aging mice, each consisting of 3 individuals, total 30, from fetal day 19 to postnatal newborn at day 1, 3, 9, 14 and adult at month 1, 2, 6, 12 to 24 were injected with 3H-thymidine a DNA precurson, another 10 groups consisting of 3 individuals, total 30, were injected with 3H-uridine a RNA precursor, and another 10 groups of 30 individuals were injected with 3H-leucine a protein precursor, total 90 individuals. Then, all the animals were sacrificed 1 hr after the injections and the liver tissues, the lung tissues, the kidney tissues, the testis and ovary tissues, the adrenal tissues were taken out, fixed and processed for electron microscopic radioautography. On electron microscopic radioautograms obtained from each animal, ten photographs in respective groups, numbers of mitochondria per cell profile area, numbers of labeled mitochondria per cell and the mitochondrial labeling index (LI) labeled with 3H-thymidine showing DNA synthesis, LI labeled with 3H-uridine showing RNA synthesis, and LI labeled with 3H-leucine showing protein synthesis, in various organs, were counted and the results in various organs in respective aging groups were compared, respectively. From the results, it was demonstrated that the numbers of mitochondria in hepatocytes as well as in 3 zones of the adrenal cortex, the zona glomerulosa, fasciculata and reticularis of mice at various ages increased from fetal day 19 to postnatal month 1 due to development and aging of animals. On the other hand, the numbers of labeled mitochondria and the labeling indices of intramitochondrial DNA syntheses incorporating 3H-thymidine in hepatocytes and 3 zones of cortical cells increased from fetal day 19 to postnatal month 1 and decreased to month 24. The numbers of labeled mitochondria and the labeling indices of intramitochondrial RNA syntheses incorporating 3H-uridine in hepatocytes and 3 zones of cortical cells increased from fetal day 19 to postnatal month 1 and decreased to month 24. The numbers of labeled mitochondria and the labeling indices of intramitochondrial RNA syntheses incorporating 3H-uridine in hepatocytes and 3 ones of cortical cells increased from fetal day 19 to postnatal month 1 and decreased to month 24. Moreover, some other organs such as the lung and the testis were also review and discussed. From the results, it was shown that the activity of intramitochnodrial DNA synthesis, RNA synthesis,
Electron microscopic radioautographic study on mitochondrial RNA synthesis in adrenal cortical and medullary cells of aging mice  [PDF]
Tetsuji Nagata
Journal of Biomedical Science and Engineering (JBiSE) , 2011, DOI: 10.4236/jbise.2011.43031
Abstract: In order to study the aging changes of intramito-chondrial RNA synthesis of mouse adrenal cells, 10 groups of developing and aging mice, each consisting of 3 individuals, total 30, from fetal day 19 to postna-tal newborn at day 1, 3, 9, 14, adult at month 1, 2, 6 and senescent animals at month 12 (year 1) and 24 (year 2) were injected with 3H-uridine, an RNA pre-cursor, sacrificed 1 hr later and the adrenal tissues were fixed and processed for electron microscopic radioautography. On electron microscopic radio-autograms obtained from each animal, the number of mitochondria per cell, the number of labeled mito-chondria with 3H-uridine showing RNA synthesis per cell and the mitochondrial labeling index in each adreno-cortical cells, in 3 zones, as well as in each adreno-medullary cells, 2 types of cells in the medulla, the adrenalin cells and the noradrenalin cells, were calculated and the results in respective aging groups were compared with each others. The results demon-strated that the number of mitochondria in adreno-cortical cells in 3 zones, the zona glomerulosa, fasciculata and reticularis of respective mice at vari-ous ages increased from fetal day 19 to postnatal month 1 reaching the plateau from month 1 to 24 due to development and aging of animals, respectively, while the number of labeled mitochondria per cell and the labeling index of intramitochondrial RNA synthesis incorporating 3H-uridine increased from fetal day 19 to postnatal month 2, reaching the maxima and decreased slightly from month 6 to month 24. On the other hand, the number of mito-chondria per cell in the medulla increased from fetal day 19 to postnatal month 1 reaching the plateau from month 1 to 24, while the number of labeled mi-tochondria per cell and the labeling index of in-tramitochondrial RNA synthesis increased from fetal day 19 to postnatal day 14, reaching the maxima and decreased from month 1 to 24. From the results, it was demonstrated that the activity of intramitochno-drial RNA synthesis in both the cortical and me-dullary cells in developing and aging mice adrenals changed due to aging of individual animals.
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Tetsuji Nagata
The Open Anatomy Journal , 2009, DOI: 10.2174/1877609400901010013]
Abstract: For the purpose of clarifying the aging changes of DNA synthesis of mouse mitochondria in adrenal medullary cells, 10 groups of aging mice, each consisting of 3 individuals, total 30, from fetal day 19 to postnatal newborn at day 1, 3, 9, 14, adult at month 1, 2, 6, 12 and 24, were injected with 3H-thymidine, sacrificed 1 hr later and the adrenal tissues were fixed and processed for electron microscopic radioautography. On electron microscopic radioautograms obtained from each animal, number of mitochondria and the number of labeled mitochondria labeled with silver grains due to 3Hthymidine showing DNA synthesis in each adrenalin cell and noradrenalin cell were counted and the results of labeling indices in respective developing groups were compared respectively. From the results, it was demonstrated that the numbers of mitochondria in both adrenalin and noradrenalin cells in the adrenal medullae of mice at various ages increased from fetal day 19 to postnatal month 6 due to aging of animals, respectively, and decreased to month 24, while the number of labeled mitochondria and the labeling indices of intramitochondrial DNA synthesis incorporating 3H-thymidine increased from fetal day 19 to postnatal day 14 (2 weeks), reaching the maxima, and decreased to month 24. It was shown that the activity of intramitochnodrial DNA synthesis in the adrenal medullary cells in aging mice increased and decreased due to aging of animals.
THREE-DIMENSIONAL OBSERVATIONS ON THICK BIOLOGICAL SPECIMENS BY HIGH VOLTAGE ELECTRON MICROSCOPY
Tetsuji Nagata
Image Analysis and Stereology , 2000, DOI: 10.5566/ias.v19.p51-56
Abstract: Thick biological specimens prepared as whole mount cultured cells or thick sections from embedded tissues were stained with histochemical reactions, such as thiamine pyrophosphatase, glucose-6-phosphatase, cytochrome oxidase, acid phosphatase, DAB reactions and radioautography, to observe 3-D ultrastructures of cell organelles producing stereo-pairs by high voltage electron microscopy at accerelating voltages of 400-1000 kV. The organelles demonstrated were Golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes, peroxisomes, pinocytotic vesicles and incorporations of radioactive compounds. As the results, those cell organelles were observed 3- dimensionally and the relative relationships between these organelles were demonstrated.
Radioautographic studies on dna synthesis of the lungs of aging salamanders
Tetsuji Nagata
International Journal of Biological and Medical Research , 2011,
Abstract: The DNA synthesis and morphological changes of the lungs of the salamanders, Hynobiusnebulosus, were studied by light microscopic radioautography. The lung tissues of 21 salamanders in 7 groups at various aging stages, from juvenile animals at 4, 6 and 8 weeks after metamorphosis, young adults at 3, 8 and 12 months after metamorphosis, and senescent adults at 5 years after metamorphosis were used for this study. They were injected intraperitoneally with 3H-thymidine (370 KBq/g body weight), and after 1 hr the lung tissues were fixed in buffered 2.5% glutaraldehyde solution for 2 hr and postfixed in 1% osmium tetroxide solution for 1 hr. The tissues were embedded in epoxy resin Quetol-812. Thick sections were cut at 2 mm on a Porter-Blum MT-6000 ultramicrotome and were coated with Konica NR-M2 emulsion by a dipping procedure for light microscopic radioautography. After exposure for 2 months, the radioautographs were developed in SDX-1 developer, stained with 0.1% toluidine blue and were observed with an Olympus Vanox light microscope, and analyzed quantitatively. As the results, the labeling indices in the nuclei of the pneumocytes, the mucous cells, the basal cells and the ciliated cells in the superficial layer as well as the fibroblasts and the endothelial cells in the deep layer changed due to aging. The labeling indices of the 3 types of cells in the superficial layer, the mucous cells, the pneumocytes and the basal cells were high from 4 weeks to 8 weeks but dropped down at 8, 12 and 60 months. These results showed that the 3 types of cells proliferated in the early stages of development from 4 to 8 weeks and completed the development in the adult stages. The labeling index of the ciliated cells was very low, which showed that they had no activity to proliferate but replaced by the immature basal cells which differentiated to the ciliated cells. To the contrary, the labeling indices of the 2 cell types in the deep layer, the fibroblasts and the endothelial cells, were lower than the cells in the superficial layer and kept very low levels at 8, 12 and 60 months after metamorphosis. Thus, it was concluded that the 4 types of cells in the superficial layer belonged to the renewing cell population and the 2 types of cells in the deep layer to the stable cell population.
Electron Microscopic Radioautographic Study on Protein Synthesis in Mitochondria of Binucleate Hepatocytes of Aging Mice
Tetsuji Nagata
The Scientific World Journal , 2007, DOI: 10.1100/tsw.2007.140
Abstract:
Electron Microscopic Radioautographic Study on Mitochondrial DNA Synthesis in Adrenal Cortical Cells of Developing and Aging Mice
Tetsuji Nagata
The Scientific World Journal , 2008, DOI: 10.1100/tsw.2008.93
Abstract:
Electron Microscopic Radioautographic Study on Protein Synthesis in Hepatocyte Mitochondria of Aging Mice
Tetsuji Nagata
The Scientific World Journal , 2006, DOI: 10.1100/tsw.2006.265
Abstract:
Edgeworth Approximation of a Finite Sample Distribution for an AR(1) Model with Measurement Error  [PDF]
Shuichi Nagata
Open Journal of Statistics (OJS) , 2012, DOI: 10.4236/ojs.2012.24046
Abstract: In this paper, we consider the finite sample property of the ordinary least squares (OLS) estimator for an AR(1) model with measurement error. We present the Edgeworth approximation for a finite distribution of OLS up to O(T1/2). We introduce an instrumental variable estimator that is consistent in the presence of measurement error. Finally, a simulation study is conducted to assess the theoretical results and to compare the finite sample performances of these estimators.
Reply to “Comments on ‘There Is No Axiomatic System for the Quantum Theory’”  [PDF]
Koji Nagata
Journal of Quantum Information Science (JQIS) , 2014, DOI: 10.4236/jqis.2014.44018
Abstract: Barros discusses that [Jose Acacio de Barros, Int. J. Theor. Phys. 50, 1828 (2011)] Nagata derives inconsistencies from quantum mechanics [K. Nagata, Int. J. Theor. Phys. 48, 3532 (2009)]. Barros considers that the inconsistencies do not come from quantum mechanics, but from extra assumptions about the reality of observables. Here we discuss the fact that there is a contradiction within the quantum theory. We discuss the fact that only one expected value in a spin-1/2 pure state 〈σxrules out the reality of the observable. We do not accept extra assumptions about the reality of observables. We use the actually measured results of quantum measurements (raw data). We use a single Pauli observable. We stress that we can use the quantum theory even if we give up the axiomatic system for the quantum theory.
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