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Biomedical subjects

S Tachi

Publications and source records attributed to S Tachi.

At least 19 recordsLinked to original sources
PubMed1999

[Networked robotics: its present status and future prospect].

One of the most promising technologies today is the integration of virtual reality and robotics on a network. This is called network robotics in general and R-cubed (real-time remote robotics) in particular. R-cubed is a Japanese national R&D scheme to realize augmented telexistence (tele-existence) through various kinds of networks including the Internet. Telexistence is a concept named for the technology that enables people to have a real-time sensation of being present at a location other than the place where they actually exist, and to interact with a remote and/or virtual environment. They can thus "telexist" in a real environment that the robot is present or in a virtual environment that a computer has generated. It is also possible to telexist in a mixed environment of real and virtual which can be called augmented telexistence. The concept of telexistence, i.e., virtual existence in a remote or computer-generated environment, has developed into the national R-cubed R&D scheme to create an advanced and comfortable life for the network society of the 21st century. Based on the national R&D scheme of R-Cubed, the Humanoid Robotics Project (HRP) was launched in April 1998. This is an effort to integrate telerobotics, network technology, and virtual reality into networked telexistence, and significant results are expected.

Forecasting↗
PubMed1997

Cell-cell contact down-regulates expression of membrane type metalloproteinase-1 (MT1-MMP) in a mouse mammary gland epithelial cell line.

Membrane type matrix metalloproteinase (MT-MMP), which possesses a C-terminal transmembrane domain, is expressed on the cell membrane (Sato et al., 1994, Nature 370: 61-65). It was suspected, therefore, that the expression of MT-MMPs might be regulated by cell-cell interactions. We examined the patterns of MT1-MMP expression in a mouse mammary gland epithelial cell line, HC11, which is capable of responding to prolactin in vitro. HC11 cells form well-differentiated monolayer of cuboidal epithelium at confluence. During the log growth phase, cells which are well dispersed and seemingly migrating actively, or located at the periphery of small colonies, reacted strongly with an anti-MT1-MMP antibody, whereas no MT1-MMP immunoreactivity was detected in the cells which established cell-cell contact with adjacent cells. At confluence, the HC11 cells lost MT1-MMP immunoreactivity completely. Northern blot analysis revealed that MT1-MMP mRNA is present at a high level in HC11 cells during the log phase of growth. Although MT1-MMP immunoreactivity disappeared by the 1st day confluence was reached, the decline of MT1-MMP mRNA levels started only a few days later. The discrepancy in the timing of decrease of MT1-MMP protein and that of the transcripts suggests the presence of translational control mechanisms for MT1-MMP expression during cell-cell interaction.

Animals↗
PubMed1993

Formation of the myelinated nerve fiber layer in the chicken retina.

Oligodendrocytes in the ganglion cell layer, the myelinating cells in the chicken retina, were investigated morphologically and quantitatively. Oligodendroblasts divided in the inner retinal layer around the 14th day of incubation and differentiated into oligodendrocytes. The oligodendrocytes started sheathing an axon in the nerve fiber layer at the 14th day of incubation. The number of myelin lamellae increased rapidly during the first week after chicks had hatched. An immunological reaction of anti-myelin basic protein was observed on the myelin sheaths in the nerve fiber layer and on the oligodendrocytes in the ganglion cell layer. These results suggest that the oligodendrocytes form the myelinated nerve fiber layer of the chicken and that they act independently of the Müller cells during myelination.

Age Factors↗
PubMed1984

Electron microscopic analysis of the effect of progesterone upon the hormone-sensitive solitary cilia and centriolar complexes in the luminal epithelial cells of the uterus of the ovariectomized-adrenalectomized rat.

The time course of the hormonally controlled deciliation cycles of the centriolar complexes in the cells of the luminal epithelium of the uterus of the ovariectomized and adrenalectomized rat was analyzed at ultrastructural levels. The results were expressed quantitatively. The half-life of the solitary cilia after progesterone administration in the cell population was 14.6 hr, longer approximately by 1 hr than that previously reported for the estrogen-induced deciliation of the same cells. The time course of the progesterone-induced loss of solitary cilia strongly suggested that the phenomenon is biphasic. After the initial loss of 50%, the process progressed slowly. Twenty-four hours after the injection of the hormone, 35% of the cilia remained; after 60 hours, 4% were still present. This is in striking contrast to the effect of estrogen, which causes almost complete deciliation within 24 hr after the injection of the hormone. Prolonged exposure of the deciliated luminal epithelial cells to progesterone leads to disarrangement of the diplosome relationship. The phenomenon might be causally correlated with the block of estrogen-induced mitoses by this hormone; this view, however, needs further experimental corroboration.

Adrenalectomy↗
PubMed1981

Possible involvement of macrophages in embryo--maternal relationships during ovum implantation in the rat.

Distribution of phagocytic cells in the rat endometrium during the estrous cycle and early gestation was examined by histological, electron microscopic, and histochemical techniques. The results show that numerous macrophages emerge around the nidus shortly after the onset of ovum implantation. Such macrophages, however, were not present within the decidua, suggesting that this tissue may be a protective barrier against the migration of phagocytic cells towards the implants. Approximately 48 hours after the onset of implantation, the number of endometrial macrophages decreased dramatically.

Animals↗