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N Fujiwara

Publications and source records attributed to N Fujiwara.

At least 145 records · Page 8Linked to original sources
PubMed1991

Mechanoreceptors of the hard palate of the Mongolian gerbil include special junctions between epithelia and Meissner lamellar cells: a comparison with other rodents.

As a part of our comparative morphological study of mechanoreceptors in rodent oral mucosae, the hard palate of the mongolian gerbil (a kind of sand rat) was investigated by light and electron microscopy. Subepithelial connective tissue papillae of palatine rugae contained a dense distribution of lamellated corpuscles that showed an ultrastructure similar to that of Meissner corpuscles of primates. The corpuscles in the palate of the mongolian gerbil, however, frequently formed compound large corpuscles with a palisade-like extension. Antemolar rugae predominated in containing such compound "Meissner" corpuscles. Superficial cytoplasmic lamellae of the corpuscles closely adhered to overlying epithelial cells without an intervening basal lamina. Although a small number of simple corpuscles was seen in the first antemolar rugae, no similar corpuscles were encountered in other parts of the palate. On the other hand, numerous Merkel cell-nerve endings were seen in epithelial pegs and sometimes in epithelial ridges of palatine rugae. Quinacrine labelling showed that intermolar rugae contained a rather dense distribution of Merkel cells in comparison with antemolar rugae. The present and previous data indicate that the pattern of palatine mechanoreceptors of the mongolian gerbil is analogous to that of the mouse, but not of the rat.

Animals↗
PubMed1991

Observation of spinal canal and cisternae with the newly developed small-diameter, flexible fiberscopes.

Small-diameter (0.5-, 0.9-, and 1.4-mm) flexible fiberscopes were developed for visual diagnosis of spinal canal diseases. The fiberscopes were introduced via a Tuohy needle into the subarachnoid and epidural spaces of ten patients with various pain syndromes. Clear visualization of the subarachnoid space was achieved using the fiberscopes. The epidural space could be visualized only during withdrawal of the fiberscope. In five cases, the fiberscope could be advanced up to the level of the cisternae without causing the patient any discomfort. A slight headache and transient fever were noted after the examination in five and two cases, respectively, but no other complications occurred. Interestingly, preexisting pain diminished (two cases) or disappeared (one case) after the myeloscopy in three of five cases in which the myeloscopy revealed aseptic adhesive arachnoiditis. Further studies should be carried out to evaluate the usefulness of this technique.

Adult↗
PubMed1991

Stimulatory effect of guanine nucleotides on prostaglandin E1 binding to murine renal outer medulla.

Prostaglandin E1 (PGE1) specifically bound to the membrane prepared from murine renal outer medulla. The extent of binding of [3H]PGE1 to the membrane was increased about 4-fold by guanosine triphosphate (GTP) and its analogs, but the dissociation of bound [3H]PGE1 from the membrane was in turn enhanced by GTP gamma S. Scatchard plot analyses revealed that GTP gamma S increased the binding affinity more than 2-fold without a major change in the number of binding sites. When [3H]PGE1-bound proteins were cross-linked in the membrane by dithiobis (succinimidyl propionate), bound [3H]PGE1 was no longer dissociated by GTP gamma S treatment, suggesting that cross-linking produced a stable complex of PGE receptor with a GTP-binding protein. The cross-linked [3H]PGE1-specifically bound proteins solubilized from the membranes labeled with [3H] PGE1 in the presence or absence of GTP gamma S were eluted as an apparently single radioactive peak at the same position of Mr = 15000 by gel filtration, indicating that the PGE receptor forms a complex with a GTP-binding protein regardless of the treatment with GTP gamma S by which [3H]PGE1 binding is promoted. The ability of GTP gamma S to stimulate [3H]PGE1 binding was eliminated by pretreatment of the membrane with pertussis toxin, but not cholera toxin, indicating that the PGE receptor is coupled to a pertussis toxin-sensitive GTP-binding protein.

Alprostadil↗
PubMed1991

Short-term mineralization of dentin and enamel in the mouse embryonic molars cultured in serum-free, chemically-defined medium.

The present study was designed to demonstrate the short term mineralization of dentin and enamel, and to investigate the effects of sodium beta-glycerophosphate (Na-beta-GPO4) on calcification in a serum-free, chemically-defined medium. The first mandibular molars at the bell stage dissected from 18-day-old mouse embryos were used as explants, which were cultured by an improved flotation method. Calcification of enamel in the 18-day-old embryonic molars occurred within the 6th day of culture. In another experiment, the molar germs were cultured in a serum-free, chemically-defined medium supplemented with 1, 5 and 10 mM Na-beta-GPO4. Promotion of tooth mineralization was recognizable at very low concentrations, such as 1 mM Na-beta-GPO4, in 18-day-old embryonic tooth germs. The culturing system reported here shortens the time required for dentin and enamel calcification to one half or one third of that reported previously and therefore should prove useful for examining regulations for cytodifferentiation and morphogenesis in tooth germs and the mineralization of dentin and enamel.

Ameloblasts↗
PubMed1991

[Anesthetic management of pheochromocytoma by continuous intravenous injection of prostaglandin E1].

We had five cases of surgical removal of pheochromocytoma by continuous intravenous injection of prostaglandin E1. During anesthesia, we used Swan-Ganz catheter for circulatory monitoring and measured plasma catecholamines. When PGE1 dose was increased from 0.05 to 0.1 and 0.15 microgram.kg-1.min-1, total systemic vascular resistance and mean arterial pressure were decreased but heart rate and cardiac output were not significantly altered from the preanesthetic values. Plasma catecholamines were also similar to the preanesthetic values. Therefore, the results suggest that the mechanism of suppression of hypertension by PGE1 is by affecting vascular beds directly rather than by diminishing catecholamine excretion from sympathetic nerve and adrenal medulla. During manipulation of pheochromocytoma, mean arterial blood pressure increased extremely. Although PGE1 was injected at a rate of 0.3 to 0.5 microgram.kg-1.min-1 in some cases, we could not suppress the elevation of blood pressure. PGE1 alone could not normalize blood pressure and heart rate, and other cardiovascular agents were necessary.

Adolescent↗
PubMed1990

A comparative electron microscopic analysis of mechanoreceptors in the hard palate of the mouse (Mus musculus; Rodentia) and the musk shrew (Suncus murinus; Insectivora).

These mechanoreceptors were studied with particular regard to their type and the distribution. In both species they were concentrated in the crests of transverse palatine rugae. In the mouse, Meissner corpuscles, glomerular corpuscles, and Merkel cell nerve endings were seen in every palatine ruga, though the first antemolar ruga also contained simple and atypical lamellated corpuscles. In contrast, the palatine rugae of the musk shrew contained only simple corpuscles and Merkel cell nerve endings. Meissner corpuscles in the mouse palate were frequently aggregated to form a palisade-like, huge corpuscle. Anterior intermolar rugae especially contained a larger number of such huge corpuscles. Simple corpuscles in the palate of the musk shrew were more densely distributed in the anterior than in the posterior rugae. In both species Merkel cell nerve endings were localized within epithelial downgrowths of the rugal crest. These downgrowths tended to increase in number anteroposteriorly.

Animals↗
PubMed1990

Effects of isoflurane on spinal inhibitory potentials.

The effects of isoflurane on segmental spinal cord potentials and heterosegmental slow positive potentials in response to fore- and hindpaw stimulation were studied in the rat. The heterosegmental slow positive potential and late (second) component of the slow positive wave (P2) of segmental spinal cord potential, thought to be primary afferent depolarization, an agent of presynaptic inhibition activated by a feedback loop via supraspinal structures, were greatly suppressed by the anesthetic. In contrast the negative wave (N1) of segmental spinal cord potential, believed to be synchronized activity of dorsal horn neurons, was only minimally affected. No differential effects of isoflurane on spinal cord potentials activated by fore- and hindpaws were found. Thus, the inhibitory activities of the spinal cord, particularly those produced by a feedback loop via supraspinal structures, are suggested to be highly vulnerable to isoflurane.

Animals↗
PubMed1990

Endothelial modulation of norepinephrine-induced constriction of rat aorta at normal and high CO2 tensions.

Endothelial modulation of norepinephrine (NE)-induced constriction of the isolated rat aorta was studied at normal (PCO2, 41 +/- 0 mmHg) and high CO2 tensions (PCO2, 91 +/- 1 mmHg). In preparations with intact endothelium, increased CO2 tension resulted in rightward shift of the NE dose-response curve with attenuation of maximal contraction. This effect of CO2 was not modified by indomethacin. Treatment with hemoglobin or rubbing of the endothelium meant that increased CO2 tension still resulted in rightward shift of the NE dose-response curve but without altering the maximal contractile response. The basal guanosine 3',5'-cyclic monophosphate (cGMP) levels in control and NE-treated aortic preparations were not affected by increasing the CO2 tension. Thus the inhibitory action of CO2 on NE-induced contraction in the presence of endothelium may not be derived from facilitation of endothelium-derived relaxation factor (EDRF)-induced cGMP synthesis. Increasing the CO2 tension attenuated the sustained contraction induced by the addition of NE and Ca2+ (2.5 mM) to intact endothelium preparations previously bathed in Ca2(+)-free solution. Further addition of Ca2+ (total 5.0 mM) did not increase the contraction. These findings suggest that the intrinsic activity of NE is greatly modified by endothelium at a high CO2 tension. Vasodilation during hypercapnia may be induced at least in part by synergistic actions of EDRF and CO2 on smooth muscle cells.

Animals↗
PubMed1990

Incidence of skin cancer among Nagasaki atomic bomb survivors (preliminary report).

Among a total of 65,268 Nagasaki atomic bomb survivors recorded in the Scientific Data Center of Atomic Bomb Disaster, Nagasaki University School of Medicine, 140 cases with skin cancer were collected from 31 hospitals in Nagasaki City from 1961 through 1987. Subsequently, these cases of skin cancer in Nagasaki atomic bomb survivors were statistically analyzed in relation to the estimated distance from the hypocenter by age, sex, histology and latent period. The results were as follows: 1. A high correlation was observed between the incidence of skin cancer and the distance from the hypocenter. 2. The incidence of skin cancer in Nagasaki atomic bomb survivors now appears to be increasing in relation to exposure distance. 3. Among 140 cases, basal cell epithelioma was observed in 67 cases (47.9%) and squamous cell carcinoma in 43 cases (30.7%).

Basal Cell Carcinoma↗
PubMed1990

The ultrastructure of the ganglionated nerve plexus in the nasal vestibular mucosa of the musk shrew (Suncus murinus, insectivora).

A ganglionated nerve plexus (GNP) found in the nasal vestibular mucosa of the adult musk shrew, and most likely belonging to the nervus terminalis, was studied by electron microscopy. The GNP, which contained ganglion cells and both myelinated and unmyelinated nerve fibers, was located in the subepithelial layer of the mesial vestibular mucosa of the snout processes. The ganglion cells were characterized by an eccentrically located round nucleus, dispersed mitochondria and Golgi apparatuses, and many small vesicles. Nissl bodies were rare. The ganglion cells, solitary or in a small group, were entirely covered with satellite cell sheaths. Semiserial sections suggested that a given ganglion cell directly extends one nerve process and plural modified cilia. There were no synaptic contacts between the ganglion cells and efferent nerve elements. On the other hand, it was seen that the epithelium overlying the GNP contained many nerve terminals which probably originated from the GNP. It is suggested that the ganglion cells in the nasal vestibular GNP of the musk shrew represent primary sensory neurons.

Animals↗
PubMed1990

Endochondral calcification by hypertrophic chondrocytes in the Meckel's cartilage grafted into the isogenic mouse spleen.

We found that when the midsection of Meckel's cartilage bars obtained from mice on the eighteenth day of gestation were grafted into isogenic mouse spleen, chondrocytes induced an endochondral calcification. Concurrent with the onset of calcification throughout Meckel's cartilage matrix, periodic banded thick collagen fibrils and matrix vesicles were observed around the chondrocytes. Although most of the chondrocytes prior to grafting were hypertrophic cells, they survived for seven days in the splenic tissue and had well-developed secretory organelles. The cells which were surrounded by calcified matrix were relatively small, spherical, and showed a morphology closely resembling that of osteocytes. These findings suggest that the life span of hypertrophic chondrocytes is influenced by the microenvironment of the spleen.

Animals↗
PubMed1990

[Surgical treatment of hypoplastic left heart syndrome: a successful case report].

A successful case of Norwood operation for a 5-day-old infant with hypoplastic left heart syndrome is reported. Norwood procedure and central shunting with a 4 mm PTFE tube was performed. Cerebral and coronary artery were perfused independently during reconstruction of aorta in order to shorten the time of circulatory arrest. Post operative UCG documented un-obstructive systemic output from the right ventricle, well regulated pulmonary arterial blood flow and widely patent interatrial communication. This baby was discharged the hospital 66 days after surgery. He has been clinically well for six month after the operation.

Anastomosis, Surgical↗
PubMed1989

Structure of phosphonoglycosphingolipid containing pyruvylated galactose in nerve fibers of Aplysia kurodai.

A phosphonoglycosphingolipid, designated as FGL-IIb, was identified in nerve fibers of Aplysia kurodai by two-dimensional thin layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). FGL-IIb was isolated from the nervous system of A. kurodai by Iatrobeads column chromatography using three solvent systems. Pyruvic acid was identified by thin layer chromatography as its 2,4-dinitrophenylhydrazone and established by permethylation studies to be attached as a ketal to O-3 and O-4 of the terminal galactose of the oligosaccharide chain in FGL-IIb. By sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, and proton magnetic resonance spectrometry, the structure of FGL-IIb was concluded to be [3,4-O-(1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3(Fuc alpha 1----2) (2-aminoethylphosphonyl----6)Gal beta 1----4Glc beta 1----1ceramide. Its major aliphatic components were palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. This is the first report of the occurrence of pyruvylated galactose as a constituent of animal sphingolipid.

Acidic Glycosphingolipids↗
PubMed1989

Epithelial cytodifferentiation and extracellular matrix formation in enamel-free areas of the occlusal cusp during development of mouse molars: light and electron microscopic studies.

Mandibular first molars in mice ranging in age from 18 days prenatal to 5 days postnatal were used for light and electron microscopic examinations of the enamel-free area (EFA) during development of the occlusal cusp (mesiobuccal cusp). Notable morphological changes in the inner enamel epithelium and the cells of the stratum intermedium were observed. At prenatal age of 18 days, the inner enamel epithelium of the EFA (EFA epithelium) was composed of a layer of columnar cells and covered by the cells of the stratum intermedium. Two days after birth, the EFA epithelium was made up largely of preameloblasts, with mitochondria located in the proximal side of the cells toward the stratum intermedium. The cells of the stratum intermedium were irregularly shaped, with wide intercellular spaces between them. At a postnatal age of 3 days, most of the EFA epithelial cells resembled maturation-stage ameloblasts, being short and columnar in shape and having nuclei located in their proximal side. Distal cell membranes were folded, and mitochondria were scattered throughout the cytoplasm. In 4-day-old mice, the EFA epithelium was found to be formed of short columnar or cuboidal cells with distinct intercellular spaces. The cells of the stratum intermedium could no longer be detected, and cells of the EFA epithelium could not be distinguished from those of the stellate reticulum. Odontoblasts of the EFA were arranged and polarized parallel to the basal lamina, and odontoblastic processes extended toward the cusp tip. The orientation of thin and thick collagen fibers within predentin and dentin was also parallel to the basal lamina. Even after dentin mineralization, disrupted basal lamina and long, aperiodic, fine fibrils were found between the epithelium and the dentin. Following the disappearance of the basal lamina and fine fibrils, stippled material and crystals appeared on the dentin surface. The mineralized matrix, which x-ray microanalytical energy peaks identified as containing calcium and phosphorus, was continuous with enamel in the distal slope of the cusp at the cusp tip. Thus, the inner enamel epithelium of the EFA differentiated into secretory cells capable of enamel-like matrix formation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

NMR study on [1-13C]glucose metabolism in the rat brain during hypoxia.

The metabolism of [1-13C]glucose in the rat brain during hypoxia was investigated by 13C NMR spectroscopy. Male Wistar rats, weighing 100-120g, were anesthetized with ketamine (50 approximately 75 mg/kg i.p.) and ventilated mechanically with a mixture of 30% oxygen, 69.5% nitrogen and 0.5% halothane. [1-13C]glucose (250 mg/kg) was infused twice, at 10 minute intervals, through the femoral vein. For the control group (n = 4), the oxygen concentration of the inspiratory gas was maintained at 30% by vol throughout the experiments. For the hypoxia group (n = 6), the oxygen concentration in the inspiratory gas was reduced to 6-7% (93-94% nitrogen) and maintained for 30 min following [1-13C]glucose infusion. 13C NMR spectra were measured by a gated proton-decoupling method without a nuclear Overhauser effect. The [1-13C]glucose infusion gave apparent signals of the C1 carbon in the alpha- and beta-anomers of [1-13C]glucose at 92.7 and 96.7 ppm, respectively. Signals of the C2, C3 and C4 carbon atoms in glutamate and/or glutamine (glx) also appeared at 55, 27 and 34 ppm, respectively. The intensity of glx-C2 and glx-C3 signals increased later than that of glx-C4. The time lag between the different glx signals may reflect the turnover rate of the TCA cycle. Under the hypoxic condition, the signal of C3 carbon in lactate appeared at 21 ppm and increased. The alpha-glucose signal diminished during hypoxia, whereas the beta-glucose signal kept its intensity. The difference in changes of the signal intensity between alpha- and beta-glucose suggests that alpha-glucose is consumed more than beta-glucose in the hypoxic brain.

Animals↗
PubMed1989

Intraperineural localization of lamellated sensory corpuscles in the skin and oral mucosae of the adult cat and miniature pig.

Lamellated sensory corpuscles in the perioral tissues of the adult cat and the adult miniature pig were studied by light and electron microscopy. In the cat lip, over half of the lamellated corpuscles existed in an aggregate form associated with other nerve elements and blood capillaries in peripheral nerve swellings, while the remainder existed in an isolated form. Conversely, almost all the lamellated corpuscles in the miniature pig existed in an aggregate form in nerve swellings. Most of the intraperineural lamellated corpuscles showed ultrastructural characteristics of simple corpuscles. However, some of the intraperineural lamellated corpuscles exhibited interlaced arrangements of tortuous axon terminals and cytoplasmic lamellae resembling the arrangement in Meissner corpuscles. Immunohistochemical staining using anti-neuron specific enolase also revealed the presence of intraperineural, Meissner-like corpuscles in the cat lip. This study indicates that intraperineural localization of lamellated corpuscles is common in carnivora and artiodactyla and that the intraperineural lamellated corpuscles are heterogeneous in their ultrastructural pattern.

Animals↗
PubMed1989

A simple, disposable, and improved organ culture system for maintaining three-dimensional development of mouse embryonic molars.

Mandibular first molars from 17-d-old mouse embryos were cultured in vitro for 2 to 4 d by a simple, disposable, improved floatation method. This method consisted of using a 24-well multidish and a plastic culture chamber with a membrane filter. The improved floatation method, as well as our previous method, was capable of the three-dimensional development of tooth germs. Cytodifferentiation of odontoblasts and ameloblasts and formation of extracellular matrices were accelerated by the present culture system, in comparison with our previous method. All the molars cultivated by this method were very similar in morphology to in vivo. On Day 2 of culture the terminal cytodifferentiation of odontoblasts and the formation of predentin were ascertained in the bucco-lingual sections of the cultured molars. A thick layer of predentin was formed at the tip of the cusp and gradually decreased toward the cervical loop and the fissure between the buccal and lingual cusps. On Day 4 in vitro, secretory ameloblasts produced enamel matrix, and the mineralized enamel showed showed prismatic structure very similar to that in vivo. Dentin and predentin also were normal in ultrastructure. The extracellular matrices (enamel, dentine, and predentin) were formed in line with the pattern of the cusp and the formation of matrices normally started at the tip of the cusp. We conclude that the three-dimensional development of whole tooth germs in vitro may be very important for normal expression of the developmental program intrinsic to mouse embryonic molars.

Animals↗