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T Yamaai

Publications and source records attributed to T Yamaai.

31 records · Page 2Linked to original sources
PubMed1995

Hepatocyte growth factor/scatter factor modulates cell motility, proliferation, and proteoglycan synthesis of chondrocytes.

Hepatocyte growth factor/scatter factor (HGF/SF) is a multifunctional growth factor that promotes proliferation, motility, and morphogenesis in epithelial cells. Recently the HGF receptor, c-met protooncogene product, has been shown to be expressed in developing limb buds (Sonnenberg, E., D. Meyer, M. Weidner, and C. Birchmeiyer, 1993. J. Cell Biol. 123: 223-235), suggesting that some populations of mesenchymal cells in limb buds respond to HGF/SF. To test the possibility that HGF/SF is involved in regulation of cartilage development, we isolated chondrocytes from knee joints and costal cartilages of 23-d embryonic and 4-wk-old rabbits, and analyzed the effects of HGF/SF on migration and proliferation of these cells. We found that HGF/SF stimulated migration of cultured articular chondrocytes but did not scatter limb mesenchymal fibroblasts or synovial fibroblasts in culture. HGF/SF also stimulated proliferation of chondrocytes; a maximum three-fold stimulation in DNA synthesis was observed at the concentration of 3 ng/ml of HGF/SF. Moreover, HGF/SF had the ability to enhance proteoglycan synthesis in chondrocytes. The responsiveness of chondrocytes to HGF/SF was also supported by the observation that they expressed the HGF/SF receptor. Addition of the neutralizing antibody to rat HGF/SF affected neither DNA synthesis nor proteoglycan synthesis in rat chondrocytes, suggesting a paracine mechanism of action of HGF/SF on these cells. In situ hybridization analysis showed that HGF/SF mRNA was restrictively expressed in the areas of future joint regions in developing limb buds and in the intercostal spaces of developing costal cartilages. These findings suggest that HGF/SF plays important roles in cartilage development through its multiple activities.

Animals↗
PubMed1995

Microgravity generated by space flight has little effect on the growth and development of chick embryonic bone.

Seven days' space flight of fertilized chicken eggs pre- incubated for 7 and 10 days on earth caused no differences in the morphology of osteoblasts, osteoclasts, and osteocytes of humerus and tibia from those of control embryos. Bone-resorbing and -forming activities of the femur were not different between control and flight groups. As a consequence, calcium and phosphorus contents of the femora between control and flight groups were not changed. Alkaline phosphatase activity of 3 different regions (resting cartilage, growth cartilage, and cortical bone) of tibia showed no significant difference between control and flight groups. No significant difference of gene expressions of hepatocyte growth factor and receptors of fibroblast growth factor was observed in perichondrium, trabecula, and skeletal muscles and tendons of hind limbs between control and flight groups. Unlike the results of previous space flight experiments in which young growing mammals were used, these morphological and biochemical results indicate that microgravity has little effect on bone metabolism of the chick embryo.

Actins↗
PubMed1995

Expression of a dopamine transporter in PC12h cells: an immunohistochemical study with an antipeptide antibody.

Two kinds of oligopeptides, based on the amino acid sequences of No. 217-232 and 374-387 of a rat dopamine transporter, were designed and chemically synthesized. Five clones of the monoclonal antibodies against these peptides were produced with the in vitro immunization method. Two of them have recognized a protein of M(r) approximately 85,000 in a synaptosomal fraction of the rat striatum. It is probable that the protein M(r) approximately 85,000 corresponds to a dopamine transporter in the nerve terminal of the dopamine neurons in the striatum. The expression of dopamine transporter was immunohistochemically examined with these antibodies in PC12h cells. The immunoreactivity was detected on the surface membrane of the cells.

Animals↗
PubMed1994

Neural parvalbumin and calretinin in the tooth pulp.

Parvalbumin- and calretinin-immunoreactivities (CR-irs) were examined in the molar tooth pulp of the rat using immunohistochemical methods. CR-ir fibers were further classified based on the tachykinin-ir revealed by a double immunofluorescence method. The rat root pulp contained three types of nerve fibers; parvalbumin-ir smooth fibers, CR-ir (TK-negative) smooth fibers and CR-ir (TK-ir) varicose fibers. These fibers projected toward the roof of the pulp chamber and pulp horn without marked ramification. In the subodontoblastic layer at the roof of the pulp chamber and pulp horn, parvalbumin-ir smooth fibers repeatedly ramified and extended varicose terminals into the odontoblastic layer. CR-ir (TK-negative) smooth fibers reached the subodontoblastic layer without marked ramification and gave rise to varicose terminals that appeared to terminate within the subodontoblastic layer. On the other hand, CR-ir (TK-ir) varicose fibers proceeded to the subodontoblastic layer at the roof of the pulp chamber and pulp horn, where they ramified and penetrated the odontoblastic layer. The present study indicates that the rat tooth pulp contains myelinated parvalbumin-ir and CR-ir (TK-negative) fibers, and unmyelinated CR-ir (TK-ir) fibers, and that they project varicose terminals to the subodontoblastic and odontoblastic layers. The central projection sites of these sensory fibers have yet to be revealed.

Animals↗
PubMed1994

Parvalbumin-like immunoreactivity in nerve fibres within human molar tooth pulps.

The root pulp contained two types of parvalbumin-immunoreactive nerve fibres, smooth and varicose. The smooth were relatively thick (mostly 3-5 microns in diameter) and sometimes had large swellings, whereas the varicose consisted of oval varicosities of 1-3 microns in long diameter with very fine strands interconnecting them. Most of the parvalbumin-immunoreactive root fibres were smooth, and the varicose were rare. Upon entering the pulp chamber, both types of fibre splayed out and ran towards the roof of the chamber and the pulp horn. In the subodontoblastic layer of the roof and horn, parvalbumin-immunoreactive fibres showed relatively straight chains of granules; they sent their granular terminals to the odontoblastic layer. Some parvalbumin-immunoreactive granules were observed in the predentine and some even in the dentine. The diameter of axons in the root pulp and the spatial distribution of terminals strongly suggest that the parvalbumin-immunoreactive fibres are mostly myelinated and sensory.

Dental Pulp↗
PubMed1993

Persistent sciatic artery. Case report.

A case of a persistent sciatic artery in a 60-year-old Japanese man is reported. The right persistent sciatic artery (5 mm in diameter) was joined to the internal iliac artery proximally and to the popliteal artery distally. The terminal vessel of the femoral artery (3 mm in diameter) was connected to the sciatic artery at the popliteal fossa.

Arteries↗
PubMed1992

Parasympathetic postganglionic nerve fibers in the fungiform papillae of the bullfrog, Rana catesbeiana.

An investigation was made of the precise origin of the unmyelinated nerve fibers in the fungiform papillae of the bullfrog's tongue. Some unmyelinated nerve fibers in the fungiform papillae originate from the parasympathetic postganglionic cells in the glossopharyngeal nerve. Axonal enlargements of the parasympathetic nerve fibers were in close contact with the Merkel-like basal or supporting cells in the taste disk. These results seem to provide morphological evidence for the existence of an efferent control system in the taste disk.

Animals↗
PubMed1990

Expression pattern of acidic and basic fibroblast growth factor genes in adult rat eyes.

Although the retinal angiogenic and mitogenic factors have been identified to be acidic and basic fibroblast growth factors (aFGF and bFGF), little information has so far been available about the cells producing them and their function in retinal tissues. We found, by in situ hybridization, that the expression pattern of the aFGF gene differed remarkably from that of the bFGF gene in adult rat eyes. Our results demonstrated that the aFGF gene was produced by photoreceptor visual cells, neuronal cells in the inner nuclear layer and ganglion cells of the retina, in addition to pigment epithelial cells of the choroid, iris and ciliary body, and epithelial cells of the cornea, conjunctiva and lens, while bFGF was synthesized solely by the photoreceptor visual cells.

Animals↗
PubMed1989

Expression of retinoic acid receptor genes in keratinizing front of skin.

We found, by an in situ hybridization method with riboprobes synthesized from human cDNA of the retinoic acid receptor (RAR), that the RAR genes (predominantly gamma-subtype) are intensively expressed in the epidermis of normal and psoriasic human skins, and also in keratinizing fronts of 4-day-old mouse skins, nail matrices and hair follicles. Thus, target cells of retinoic acid in the skins are concluded to be keratinocytes, which is quite consistent with the fact that retinoic acid regulates keratinization of epidermis in vivo and also modulates expression of the keratin gene in vitro.

Animals↗
PubMed1989

Spatial and temporal expression pattern of retinoic acid receptor genes during mouse bone development.

Spatial and temporal expression pattern of retinoic acid receptor (RAR) genes was investigated in mouse finger bones during development by an in situ hybridization method with riboprobes synthesized from a human cDNA of the RAR-alpha. We found that the RAR genes are expressed intensively and specifically in calcifying fronts of the mouse finger bones, whereas the expression pattern is rather uniform in the limb buds and cartilage matrices of the embryonic fingers. Our findings are consistent with the fact that vitamin A is essential for normal mammalian bone development.

Animals↗
PubMed1989

A case of complete ureteropelvic duplication.

A case of complete ureteropelvic duplication is reported. In this case, two ureters, i.e. a ureter from the superior renal pelvis and one from the inferior renal pelvis, began within the sinus of the left kidney. This case was in agreement with the "Weigert-Meyer Law".

Abnormalities, Multiple↗
PubMed1989

[Localization of epidermal growth factor and nerve growth factor mRNAs in mouse submandibular gland by a simplified in situ hybridization with riboprobes].

We simplified procedures of in situ hybridization with riboprobes on serial sections of paraffin-embedded tissues. We found that when tissues were fixed with 4% paraformaldehyde, embedded in paraffin, and cut serial sections with 5 microns thick, excellent results were obtained without proteolytic, heat, or HCl treatment. With our simplified method, both EGF and NGF mRNAs were detected intensively and specifically in granular convoluted tubule (GCT) cells of a male mouse submandibular gland, but not detected in either the acini or ducts other than the GCT. Accumulation of the silver grains was localized in the basal side of the GCT cells. No significant hybridization was observed in those cells with the sense probe and in the parotid and sublingual gland even with the anti-sense probe. Since our results were not only very consistent with other data, but also much more excellent than other results obtained by in situ hybridization on the similar tissues, our simplified method should be very useful to study gene expression on tissue sections.

Animals↗