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Biomedical subjects

K Kurihara

Publications and source records attributed to K Kurihara.

At least 253 records · Page 14Linked to original sources
PubMed1987

Hemorrhagic cyst of the mandible associated with a retained root apex of the lower third molar.

An unusual case of hemorrhagic cyst of the mandible, associated with a retained root of the lower right third molar, is reported. The cyst was revealed by routine radiologic examination as part of treatment of the lower right second molar. Radiologically, a faintly outlined cavity with radiopaque mass was found in the third molar region. A final diagnosis of this condition was made after surgical intervention and histologic examination. A nonepithelial lining cavity was found, and the radiopaque mass was identified as a root apex.

Adult↗
PubMed1987

Cell suspensions from porcine olfactory mucosa. Changes in membrane potential and membrane fluidity in response to various odorants.

A suspension of olfactory epithelial cells was prepared from porcine olfactory mucosa and the physiological functions of the suspension were examined. The membrane potential of the cell suspension, which was monitored by measuring the fluorescence changes of rhodamine 6G, was depolarized by an increase in the K+ concentration in the external medium. Various odorants depolarized the cell suspension in a dose-dependent fashion. The magnitude of depolarization by odorants was either unchanged or slightly increased by a reduction of the concentration of Na+, Ca2+, and Cl- in the external medium, which suggests that changes in the permeabilities of specific ions are not involved in depolarization by odorants. The application of various odorants to the cell suspension induced changes in the membrane fluidity at different sites of the membrane that were monitored with various fluorescent dyes [8-anilino-1-naphthalene sulfonate, n-(9-anthroyloxy) stearic acids, 12-(9-anthroyloxy) oleic acid, and (1,6-diphenyl-1,3,5-hexatriene)], which suggests that the odorants having different odors are adsorbed on different sites in the membrane. On the basis of these results, a possible mechanism of odor discrimination is discussed.

Animals↗
PubMed1987

Pathological characteristics of metastatic carcinoma in the human mandible.

Based on the large celloidin-embedded section method, human mandibles from 62 autopsied carcinoma cases were examined histologically to determine the pathological characteristics of any mandibular metastases. Metastasis was confirmed histologically in 10 (16%) of the 62 cases and was comparatively frequent with gastric and pulmonary carcinomas. The hemopoietic areas in the mandibular marrow seemed to favor the early deposition of tumor cells. These micrometastatic foci seemed to increase in size, spreading to all parts, including the periodontal tissue or anterior part of the mandibular body. Increased hemopoietic activity following lodgement, seemed to play an important role for further metastases. Roentgenographic examination did not seem to be the best method of detecting metastasis.

Adenocarcinoma↗
PubMed1987

Androgen responsiveness of proteinase F in the submandibular salivary glands of inbred mice.

Using the radioimmunoassay technique, we studied androgenic regulations of proteinase F in the submandibular salivary glands (SMG) of various mouse strains (ICR, BALB/CA, C3H/HeN, C57BL/10N, and DBA/2N). The proteinase contents in BALB/CA and DBA/2N mice were almost the same between males and females. However, prominent sex differences in enzyme content were seen in all other strains; i.e., male glands of C3H/HeN and C57BL/10N contained more proteinase F than female glands did. On the contrary, the enzyme level in the ICR was exceedingly higher in females than in males. The enzyme contents in ICR SMG increased in males following castration and decreased after androgen injection in both castrated males and normal females. On the contrary, the enzyme level in C3H/HeN was decreased by castration and increased by androgen injection. Therefore, these sex differences in ICR and C3H/HeN mice depend on androgen, though the direction of the response is opposite.

Animals↗
PubMed1986

Contribution of electrostatic and hydrophobic interactions of bitter substances with taste receptor membranes to generation of receptor potentials.

The effects of changed ionic environments on the frog taste nerve responses to the bitter substances were examined. The responses to quinine and strychnine carrying a positive charge were suppressed by an increase in ionic strength of stimulating solutions. It was concluded that electrostatic interaction of these positive bitter substances with the receptor membranes greatly contributes to the adsorption of the substances on the membranes and that this interaction was suppressed by an increase in ionic strength. The responses to neutral bitter substances (caffeine and theophylline) were unchanged by an increase in salt concentration. The zeta potential of the mouse neuroblastoma (N-18 clone), which was depolarized by various bitter substances similarly to a taste cell, was measured in the presence of the bitter substances. The zeta potential was a little changed by quinine and practically unchanged by strychnine, caffeine and theophylline. The membrane fluidity of the N-18 cell monitored with 2-(9-anthroyloxy)stearic acid was changed in response to the bitter substances, while the fluidity monitored with 12-(9-anthroyloxy)stearic acid or 1,6-diphenyl-1,3,5-hexatriene was unchanged. This suggested that the bitter substances are adsorbed on the hydrophobic region near the surface and induce a conformational change at the region. The depolarization by the bitter substances seems to stem from changes in the "boundary potential" at the region near the surface within the membrane interior.

Adsorption↗
PubMed1986

Relative degradation of different arachidonoyl molecular species of choline glycerophospholipids in opsonized zymosan-stimulated rabbit alveolar macrophages.

The relative degradation of arachidonoyl molecular species of glycerophospholipids prelabeled with [3H]20:4 caused by opsonized zymosan was studied in rabbit alveolar macrophages using a recently developed high-performance liquid chromatographic method. The opsonized zymosan caused the release of [3H]20:4 only from choline glycerophospholipids, no significant changes being observed in the radioactivities of other glycerophospholipids and triacylglycerol. Choline glycerophospholipids were resolved into seven arachidonoyl molecular species, which differed as to the alkyl ether or acyl residue bound at the 1-position, by high-performance liquid chromatography. Arachidonate was predominantly located in the alkyl type having 16:0 at the 1-position which comprised more than half of the total arachidonoyl molecular species of choline glycerophospholipids. The radioactivities of all arachidonoyl molecular species of choline glycerophospholipids, except for the 18:2-20:4 and 18:1-20:4 species of diacylglycerophosphocholine, decreased to 80-85% of the control values as a result of the challenge with opsonized zymosan for 1 h. However, 50% of the released 20:4 came from the 16:0-20:4 species of alkylacylglycerophospholipids, which were the most predominant species of choline glycerophospholipids. The present results indicate that the 16:0-20:4 species of alkylacylglycerophosphocholine is a significant source of arachidonate and 1-O-alkyl-2-lysoglycerophosphocholine, the precursor of the platelet-activating factor, relative to other arachidonoyl species in activated alveolar macrophages.

Animals↗
PubMed1986

Synergistic effects of 5'-nucleotides on rat taste responses to various amino acids.

Synergism between 5'-nucleotides and L-amino acids in the rat taste nerve responses was investigated. The synergism was examined between low concentration of the nucleotides which induce only a negligibly small response and various concentrations of amino acids. A marked synergism was found between 5'-nucleotides and all the amino acids examined. Purine 5'-nucleotides such as GMP, deoxy GMP, GDP, GTP, AMP or IMP exhibited the synergistic effect on the responses to amino acids, while pyrimidine 5'-nucleotides such as CMP or UMP exhibited practically no synergistic effect. The presence of GMP led to a shift of the concentration-response curves for amino acids to a lower concentration region without affecting the response of the saturation level. These curves were analyzed under the assumption that there exist two types of receptor sites with different dissociation constants for each amino acid. The results suggest that GMP leads to a decrease in dissociation constants, especially for high affinity sites without affecting maximal responses. Monosodium glutamate (Glu) itself, which is known as a typical 'flavor potentiator', exhibited no enhancing effect on the responses to 4 primary taste stimuli. The mechanism of how Glu and the 5'-nucleotides 'potentiate' flavor of food is discussed.

Amino Acids↗
PubMed1986

Tridimensional observation of fluorescent granular perithelial (FGP) cells in rat cerebral blood vessels.

The tridimensional appearance and distribution of FGP (fluorescent granular perithelial) cells was studied by means of light and scanning electron microscopy. In young rats they first appeared as hexagonal cells in that were closely associated; later they transformed into slender forms and were loosely arranged. Scanning electron microscope observation gave a general view of FGP cells, their globular vacuolated inclusions, and their hypertrophied protrusion into the luminal surface of blood vessels. The nodular protrusions may be related to the limitation of blood flow in small cerebral blood vessels.

Animals↗
PubMed1986

Localization of the Trypanosoma cruzi-specific Mr 25,000 antigen by immune electron microscopy using monoclonal antibodies.

Two monoclonal antibodies reacted with the Trypanosoma cruzi-specific antigen of an apparent Mr 25,000 from all developmental forms (Tachibana et al. 1986). This T. cruzi-specific antigen was found at the plasma membrane by immunoperoxidase electron microscopy using the monoclonal antibodies TCF48 and TCF87. The TCF48 and TCF87-treated cells showed stain deposits at the plasma membrane clearly distinguishable from those in cells treated with a monoclonal antibody against a surface antigen. This suggests that the epitope(s) of the Mr 25,000 antigen is located on the inner surface or in the matrix of the plasma membrane. TCF48 and TCF87 also reacted with an antigen on the microtubules of the axoneme, but not with the subpellicular microtubules. These results suggest that the T. cruzi-specific Mr 25,000 antigen is common to both the plasma membrane and axoneme but it is not located at the subpellicular microtubules. Its identity and that of the surface antigen, Gp25 (Scharfstein et al. 1983) as well as its role in the pathogenicity of the parasite are discussed.

Animals↗
PubMed1986

Promotion of cell-substratum adhesion of clonal rat pheochromocytoma cells (PC12) by factors contained in glioma-conditioned medium (GCM): separation of two active factors contained in GCM.

Culture medium conditioned over C6 glioma cells (GCM) contains factors which induce neurite outgrowth from clonal rat pheochromocytoma (PC12) cells. The effects of GCM on the cell-substratum adhesion of PC12 cells, which is an early event required for the neurite outgrowth, were investigated. The results obtained are as follows. Addition of GCM promoted the adhesion of PC12 cells specifically to collagen-coated tissue culture dish. The GCM-promoted adhesion of PC12 cells was prevented by the treatment of the cells with cytochalasin B, concanavalin A and glycosidase mixture suggesting the contribution of microfilaments and cell surface carbohydrates in the cell adhesion. GCM did not increase significantly the intracellular content of cAMP and the extent of cell adhesion promoted by cAMP or dibutyryl-cAMP was much less than that by GCM. Two active factors contained in GCM were separated by either gel filtration or chromatofocusing using the cell adhesion assay as an index. The first factor with an apparent mol. wt. around 40,000 had the abilities to induce the neurite outgrowth and to enhance the choline acetyltransferase activity in addition to the ability to promote the adhesion of PC12 cells. The second factor with an apparent mol. wt. around 10,000 was devoid of the ability to induce the neurite outgrowth, but had the abilities to enhance the choline acetyltransferase activity and to promote the adhesion of PC12 cells. Both factors were sensitive to trypsin digestion and relatively heat stable. The significance of these factors in the neuronal differentiation was discussed.

Adrenal Gland Neoplasms↗
PubMed1986

Cholinergic differentiation of clonal rat pheochromocytoma cells (PC12) induced by factors contained in glioma-conditioned medium: enhancement of high-affinity choline uptake system and reduction of norepinephrine uptake system.

The effects of glioma-conditioned medium (GCM) and factors contained in GCM on the neurochemical differentiation of the PC12 clone of rat pheochromocytoma cells were investigated. The results obtained are as follows. The accumulation of choline into PC12 cells proceeded through two uptake systems with high (Km = 3.20 microM) and low (Km = 65.2 muM) affinities as revealed by least-squares iterative fitting of a substrate-velocity curve to the data. Culturing of PC12 cells in the presence of GCM led to a 5-fold increase in the Vmax value of the high-affinity uptake system without affecting the Km of the high-affinity uptake system. Both Km and Vmax of the low-affinity uptake system were unaffected by the GCM treatment. The high-affinity choline uptake system in both GCM-treated and untreated PC12 cells was devoid of Na+ dependency and showed low sensitivity to hemicholinium-3. The ratio of [3H]acetylcholine converted from [3H]choline taken up by PC12 cells at 1 muM choline for 1 h was two-fold higher than that by untreated cells. PC12 possess a high-affinity norepinephrine uptake system. Culturing of PC12 cells in the presence of GCM led to a decrease in the rate of uptake of 3 muM norepinephrine to 43% of that in control cells. The 40-K and 10-K fractions isolated by gel filtration of GCM had both abilities to enhance the high-affinity choline uptake system and to suppress the high-affinity norepinephrine uptake system. From these observations it was concluded that GCM contains factors which induce the cholinergic neuronal differentiation of PC12 cells.

Acetylcholine↗
PubMed1986

Taste receptor mechanism of salts in frog and rat.

Salts carrying impermeable organic cations elicited large responses in the frog and rat taste nerves. Amiloride suppressed the responses of the frog and rat taste nerves to NaCl, KCl and the organic salts to a similar extent. The estimated equilibrium potentials for Na+ and K+ at the thresholds determined were more negative than the resting potentials of the taste cells. The results obtained suggest that the taste responses to salts including NaCl are not induced by entry of cations via apical membranes of taste cells.

Amiloride↗
PubMed1986

[n-Hexane polyneuropathy due to sniffing bond G10--clinical and electron microscopic findings].

Two cases of n-hexane polyneuropathy due to glue sniffing were reported and the clinical features, laboratory data and sural nerve biopsy findings were discussed. Case 1 was a 31-year-old man and case 2 was a 24-year-old man. Both of them developed motor dominant polyneuropathy subacutely after inhalating Bond G10 for about 3 months. Their weakness deteriorated further for about 3 months even after discontinuing Bond G10 inhalation and they became almost confined to wheel chairs. Thereafter, however, they started to recover fairly rapidly. Gas chromatographic analysis of Bond G10 revealed that it contains 47.7% of n-hexane and 21.8% of toluene. Almost all reported cases of glue sniffer's neuropathy were motor dominant type, but those of n-hexane polyneuropathy of factory workers were sensory or sensorimotor neuropathy. Therefore our cases are thought to be typical of glue sniffer's neuropathies. Sural nerve biopsies were done in both patients, and examinations of photomicroscope, teased method and electronmicroscope were performed. From our photomicroscopic examinations we found only mild changes such as reduction of number of myelinated fibers, and from our electronmicroscopic examinations we noted marked accumulation of neurofilaments and loss of neurotubules in swelled axons. Some axons were normal in appearance by photomicroscopic examination, but the same axons under electronmicroscopic examination further revealed that neurotubules were oppressed by accumulation of neurofilaments to the margin of an axon. These findings seem to indicate the pathological processes of axonal swellings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗