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Biomedical subjects

Y Koshihara

Publications and source records attributed to Y Koshihara.

At least 19 recordsLinked to original sources
PubMed1992

Interleukin-4 enhances in vitro mineralization in human osteoblast-like cells.

The effect of human interleukin-4 (hIL-4) on mineralization in human osteoblast-like cells was investigated. Confluent cells were incubated with hIL-4 for 16 or 30 days in the presence or absence, respectively, of alpha-glycerophosphate (alpha-GP), which accelerates the mineralization process. hIL-4 (0.3 ng/ml) induced mineralization with 1.9-, 26- and 37-fold increases of hydroxyproline, calcium, and osteocalcin content, respectively, in the presence of alpha-GP. Mineralization was not induced with other cytokines, hIL-1, hIL-2, hIL-6, or mIL-4. hIL-4 also induced mineralization in the absence of alpha-GP in a manner different from that of 1 alpha, 25(OH)2 vitaminD3 (1,25(OH)2VD3). These findings suggest that IL-4 may play an important role in bone formation.

Alkaline Phosphatase↗
PubMed1991

Prostaglandin D2 metabolite stimulates collagen synthesis by human osteoblasts during calcification.

We investigated the effect of the prostaglandin D2 metabolite delta 12-PGJ2 (9-Deoxy-delta 9, delta 12-13,14-dihydroprostaglandin 2D) on collagen synthesis in human osteoblasts. delta 12-PGJ2 at 10(-5) M enhanced collagen synthesis in the presence of 2 mM alpha-glycerophosphate-2Na. The stimulative effect appeared as early as 3 days after addition and continued until 22 days. The enhancement of type I collagen synthesis was confirmed by polyacrylamide gel electrophoresis. The potency was the same as 10(-8) M 1 alpha, 25 dihydroxy vitamin D3 (1,25(OH)2D3). Northern blot analysis showed that 10(-5) M delta 12-PGJ2 and 10(-8) M 1,25(OH)2D3 enhanced the transcription of type I procollagen (alpha 1) mRNA levels in osteoblasts.

Blotting, Northern↗
PubMed1991

Mineralization ability of cultured human osteoblast-like periosteal cells does not decline with aging.

Studies of the mechanisms of osteoporosis have not yet determined whether these conditions result from increased osteoclast activity or decreased osteoblast activity, or perhaps both. Osteoporosis is related to aging and to postmenopausal status. The function and the mitotic capacity of cultured human osteoblast-like cells were investigated in this study. The age at which these cells lose the ability to divide showed a strong negative correlation with donor age (r = .815, p less than .01). There was also significant correlation of maximum cell saturation density with donor age (r = .698, p less than .01). Alkaline phosphatase (ALP) activity and mineralization ability, typical functions of osteoblasts, continue undiminished up to the point at which mitotic capacity ceases. When cells were treated with 1 alpha, 25-dihydroxy vitamin D3 in the presence of 2 mM alpha-glycerophosphate, ALP activity and mineralization ability showed an increase, rather than a decrease, with advancing donor age. However, these functions showed no correlation with in vitro cell aging. We propose that human osteoblast-like cells from elderly subjects do not lose their functions of mineralization and ALP formation, and that loss of these functions with cell aging does not correlate with advancing age.

Adolescent↗
PubMed1991

Enhancement of in vitro mineralization in human osteoblasts by a novel prostaglandin A1 derivative TEI-3313.

Human osteoblasts derived from long bone periosteum were induced to mineralize in culture in the presence of 2 mM alpha-glycerophosphate, with typical characteristics of mineralization, namely, accumulation of hydroxyapatite and increases in alkaline phosphatase activity and in osteocalcin production. Mineralization was also enhanced by 10(-8) M 1 alpha, 25-dihydroxyvitamin D3. In this system, a prostaglandin A1 derivative, TEI-3313, with the chemical structure 5-[(Z,2E)-4,7-dihydroxy-2-heptenyridene]-4-hydroxy-2-methylthio-4- (4- phenoxybutyl)-2-cyclopentenone, was found to enhance mineralization as effectively as 1 alpha, 25-dihydroxyvitamin D3, although its potency was 10 times lower than that of the vitamin D3 metabolite. Osteocalcin, a bone-specific noncollagenous matrix protein, accumulated onto the cell layers by treatment with TEI-3313 to a much greater extent than those released into the culture medium. TEI-3313 also enhanced collagen synthesis. Based on the finding that TEI-3313 enhanced the synthesis of both collagen and noncollagenous protein, it is speculated that TEI-3313 enhanced the mineralization by stimulating the expression of various genes in osteoblasts.

Adult↗
PubMed1989

Prostaglandin D2 stimulates calcification of human osteoblastic cells.

Studies on prostaglandin (PG) regulation of bone formation and resorption metabolism have been complicated by the heterogeneity of the tissue, which involves the interaction between and the activities of two bone cell types, osteoblasts and osteoclasts. In a simplified assay system using a cultured human osteoblastic cell line which has the capacity to form calcified tissue, we determined the effects of PGs on calcification. Of the PGs tested, PGD2 has a remarkable stimulatory activity on osteoblast calcification, but that the effective form is probably a metabolite, delta 12-PGJ2. This calcification function is not cAMP-mediated. PGD2 acts directly on osteoblast to cause stimulation of calcification.

Calcification, Physiologic↗
PubMed1989

Establishment of human osteoblastic cells derived from periosteum in culture.

We isolated osteoblastic cells derived from human periosteum and established them in culture. Their growth depended on the presence of ascorbic acid, and the doubling time was 40 to 60 h. The requirement for ascorbic acid was used to high production of collagen. These cells produced mainly type I collagen and only small amounts of type III collagen determined by reducing sodium dodecyl sulfate SDS-polyacrylamide gel electrophoresis. The total collagen yield was about 10 mg from 2 X 10(7) cells. The cells could be continuously cultured in alpha-minimum essential medium supplemented with 10% fetal bovine serum for 18 to 40 population doubling levels, depending on the age of the donated periosteum. These cells have the ability to calcify when incubated with 2 mM alpha-glycerophosphate-Na2. Calcification as viewed by the naked eye appeared from Day 15 after treatment. Treatment with the active formed vitamin D3, 1, 25 dihydroxyvitamin D3 enhanced calcification significantly and stimulated osteocalcin production. By electron microscopy, cells with many projections on their surfaces showed well-developed rough endoplasmic reticulum and actinlike fibers, and larger numbers of lysosomes, mitochondria, and secretion granules. Many matrix vesicles, in which minerals were initially localized, and well-banded collagen fibrils were seen in the intercellular spaces. These observations demonstrate typical osteoblastic morphology. The above results indicate that cultured cells from human periostem are osteoblastic cells that have the capacity to differentiate into osteocytes and to deposit calcified minerals in response to 1,25 dihydroxyvitamin D3.

Alkaline Phosphatase↗
PubMed1989

Modulation by glycyrrhetinic acid derivatives of TPA-induced mouse ear oedema.

1. The anti-inflammatory effects of glycyrrhetinic acid and its derivatives on TPA (12-O-tetradecanoylphorbol-13-acetate)-induced mouse ear oedema were studied. The mechanisms of TPA-induced ear oedema were first investigated with respect to the chemical mediators. 2. The formation of ear oedema reached a maximum 5 h after TPA application (2 micrograms per ear) and the prostaglandin E2 (PGE2) production of mouse ear increased with the oedema formation. 3. TPA-induced ear oedema was prevented by actinomycin D and cycloheximide (0.1 mg per ear, respectively) when applied during 60 min after TPA treatment. 4. Of glycyrrhetinic acid derivatives examined, dihemiphthalate derivatives (IIe, IIe', IIIa, IIIa', IVa, IVa') most strongly inhibited ear oedema on both topical (ID50, 1.6 mg per ear for IIe, 2.0 mg per ear for IIIa and 1.6 mg per ear for IVa) and oral (ID50, 88 mg kg-1 for IIe', 130 mg kg-1 for IIIa' and 92 mg kg-1 for IVa') administration. 5. Glycyrrhetinic acid (Ia) and its derivatives applied 30 min before TPA treatment were much more effective in inhibiting oedema than when applied 30 min after TPA. A dihemiphthalate of triterpenoid compound IVa completely inhibited oedema, even when applied 3 h before TPA treatment. 6. Glycyrrhetinic acid (Ia) and deoxoglycyrrhetol (IIa), the parent compounds, produced little inhibition by oral administration at less than 200 mg kg-1. 7. These results suggest that the dihemiphthalate derivatives of triterpenes derived from glycyrrhetinic acid by chemical modification are useful for the treatment of skin inflammation by both topical and oral application.

Animals↗
PubMed1989

[Study on two-dimensional tooth mobility].

Tooth mobility was measured with the use of a two-dimensional displacement measuring system. This small-sized system can measure the displacement both in the direction of the tooth axis and the buccolingual direction simultaneously with no contact. As test teeth, lower right first premolars with no clinical mobility were examined. The load was applied from the lingual to the buccal direction, to the vertical direction as well as from the buccal to the lingual direction. The results obtained were as follows: 1. This system possesses sufficient accuracy and reproducibility for tooth mobility measurement (measurement range 500 microns, resolving power 1 microns). 2. Most of the load-displacement curves showed diphasic displacement. 3. As to the amount of displacement in the buccolingual direction, 3 of 8 cases showed greater values by the load in the buccal direction and the remaining 5 by the load in the lingual direction. 4. As to the displacement direction of loaded teeth, the lingual and buccal load displaced teeth to the lingual-coronal and buccal-radicular directions respectively. Teeth under the vertical load were displaced almost to the radicular and slightly to the buccal direction. 5. As to the direction of tooth displacement in relation to load directions, it appeared that the teeth not only rotated within the dental sockets but also indented or extruded into the dental sockets.

Dental Stress Analysis↗
PubMed1988

A new 5-lipoxygenase selective inhibitor derived from Artocarpus communis strongly inhibits arachidonic acid-induced ear edema.

Natural compounds isolated from the Indonesian plant, Artocarpus communis, inhibit 5-lipoxygenase of cultured mastocytoma cells. One of five compounds, AC-5-1, strongly inhibits 5-lipoxygenase with a half-inhibition dose of 5 +/- 0.12 X 10(-8) M. However, prostaglandin synthesizing activity is not inhibited until 10(-5) M. AC-5-1 is a highly selective inhibitor for 5-lipoxygenase. The AC-5-1 at 10(-5) M inhibits 96% of leukotriene C4 synthesis of mouse peritoneal cells facilitated by calcium-ionophore. Arachidonic acid-induced ear edema of mice, an in vivo inflammatory model, involving leukotriene induction, is strongly inhibited by AC-5-1 in a dose-dependent manner. The inhibition is the strongest of any inhibitors of 5-lipoxygenase reported previously. Since the natural compound AC-5-1 can selectively inhibit 5-lipoxygenase and affect in vivo inflammation, it will be interesting to investigate the role of leukotrienes on inflammation and other physiological processes.

Animals↗
PubMed1988

Type V collagen selectively inhibits human endothelial cell proliferation.

Type V collagen from human placenta remarkably inhibited human umbilical vein endothelial cell (HUVEC) proliferation in a dose-dependent manner when coated on the culture dishes. Other types of collagen (I, III, IV) and fibronectin enhanced HUVEC proliferation under the same conditions. The inhibitory activity of type V collagen was seen not only when it was coated on the dishes, but also when it was directly added into cell culture. The attachment effect of type V collagen did not differ from that of type I collagen. The inhibitory activity is a phenomenon selective for endothelial cells, since type V collagen did not affect the proliferation of human umbilical vein smooth muscle cells, aortic smooth muscle cells, or nasal mucosa fibroblasts.

Cell Adhesion↗
PubMed1988

Sulfidopeptide-leukotrienes are major mediators of arachidonic acid-induced mouse ear edema.

The inflammatory response of the mouse ear to topical application of arachidonic acid (2 mg/ear) was examined to study the roles of sulfidopeptide-leukotrienes (LTs) and prostaglandin (PG) E2 as mediators of edema. The increase in ear thickness caused by arachidonic acid (AA) (edema), reached a maximum at 45 to 60 min after AA application. The amounts of immunoreactive LTC4 and immunoreactive PGE2 produced increased significantly in 5 to 10 min, and then diminished gradually over 60 min. 5-lipoxygenase inhibitors, dual cyclooxygenase/lipoxygenase inhibitors and anti-histamines significantly inhibited AA-induced ear edema. Both production of PGE2 and LTC4 were suppressed by NDGA at 1 mg/ear which also inhibited ear swelling. However aspirin, which enhanced LTC4 production in AA-induced ear edema did not inhibit the ear swelling. Hypodermic injection of LTC4 at 25 ng or PGE2 at 500 ng/ear did not cause swelling, but edema was induced when both compounds were injected simultaneously. Moreover ear swelling was induced by injection of both LTD4 at 50 ng and PGE2 at 500 ng/ear. Furthermore, concomitant injection of histamine, at 500 ng or serotonin at 50 ng/ear with LTC4 at 25 ng caused ear swelling but both compounds at the same dose alone did not induce swelling. These results suggest that AA-induced ear edema is predominantly mediated by LTC4 and other lipoxygenase products while PGE2 (in the presence of LTs) acts to facilitated ear swelling, although serotonin and histamine may also contribute.

Animals↗
PubMed1988

Inhibitory effect of glycyrrhetinic acid derivatives on arachidonic acid-induced mouse ear oedema.

The inhibitory effects of glycyrrhetinic acid and its derivatives were examined on arachidonic acid (AA)-induced ear oedema in mice. Of the compounds, dihemiphthalate derivatives of 18 beta-olean-12-ene-3 beta, 30-diol (IId, IId'), 18 beta-olean-9(11)12-diene-3 beta, 30-diol (IIIa, IIIa') and olean-11, 13(18)-diene-3 beta, 30-diol (IVa, IVa') showed a strong inhibition of ear oedema on both tropical (ID50, 1.9, 2.8 and 1.7 mg/ear, respectively) and oral (ID50, 90, 130 and 88 mg kg-1, respectively) administration. Topical ID50 values were approximately the same potency as nordihydroguaiaretic acid (ID50, 2.1 mg/ear). Given topically these compounds were also capable of inhibiting PGE2 and LTC4 formation at an early stage of AA-induced ear oedema. However, glycyrrhetinic acid (Ia) and deoxoglycyrrhetol (IIa), the fundamental skeletons of the derivatives, showed no detectable inhibition of oedema at a dose of 1 mg/ear (topical) or 200 mg kg-1 (oral). The most effective time for the topical administration of the compound IId against ear oedema was 0-30 min before AA application; this is different from dexamethasone which requires a time lag for reaction. The results suggest that the inhibitory effect of the hemiphthalate compounds (IId, IId', IIIa, IIIa', IVa and IVa') is a direct action, and does not involve the anti-inflammatory action of steroids mediated by the secondary formation of a reactive protein.

Administration, Topical↗
PubMed1988

Measurement of sulfidopeptide leukotrienes and their metabolism in human synovial fluid of patients with rheumatoid arthritis.

Leukotriene (LT)C4 in the synovial fluid of patients with osteoarthritis deformans (OA) and rheumatoid arthritis (RA) was measured by radioimmunoassay (RIA) after extraction with Sep-Pak C18 cartridge. The amounts of immunoreactive LTC4 (i-LTC4) in samples from patients with OA and RA were not significantly different, being 0.198 +/- 0.018 pmol/ml (n = 11) and 0.179 +/- 0.016 pmol/ml (n = 12), respectively. After separation by high performance liquid chromatography (HPLC) and measurement by RIA, the levels of other sulfidopeptide LTs, such as LTD4 and LTE4, in synovial fluid from patients with RA were found to be significantly higher than those in fluid from patients with OA. The leukocyte number in synovial fluids did not correlate with the i-LTC4 level. The metabolic activities of these synovial fluids were determined by incubating them with 3H-LTC4 and then separating sulfidopeptide LTs by HPLC. The conversion of LTC4 to LTD4 in synovial fluids of patients with OA and RA were similar, but the dipeptidase activity converting LTD4 to LTE4 was higher in fluid from patients with RA. It is suggested that a high level of LTE4 may contribute to exudation of synovial fluid, since LTE4 increases vascular permeability.

Arthritis, Rheumatoid↗
PubMed1987

In vitro calcification in human osteoblastic cell line derived from periosteum.

Human osteoblastic cell cultures were established from human periosteum, identified on the basis of high alkaline phosphatase activity in the confluent state. The cells in the growing state showed a fibroblastic morphology and grew to form multiple layers. The cells could spontaneously calcify, and the process was accelerated by alpha-glycerophosphate. Minerals deposited on the cells consisted exclusively of calcium and phosphorus, and matured into hydroxyapatite crystals. The calcification was stimulated by the treatment with 1 alpha,25-dihydroxy-vitamin D3. These results indicate that the osteoblastic cells have the capacity to differentiate into osteocytes and form calcified human bone tissue in vitro.

Adult↗