Biomedical subjects

H Akedo

Publications and source records attributed to H Akedo.

At least 91 records · Page 5Linked to original sources

PubMed1989

Secretion of transforming growth factor-beta by human myelogenous leukemic cells and its possible role in proliferation of the leukemic cells.

Transforming growth factor (TGF)-beta activity was found in the neutral extracts of human myelogenous leukemic cells or K562 cells and the conditioned medium from K562 cell culture. BALB/c 3T3 cells grown in soft agar in the presence of TGF-beta 1 produced an activity that stimulated the growth of K562 cells. This activity was non-dialyzable, acid-stable, heat-sensitive and partially inactivated by pronase treatment. These results suggest a mutual growth reliance between the leukemic cells and fibroblasts mediated by paracrine growth factors produced by these cells.

Animals↗

PubMed1989

Inhibition of in vitro tumor cell invasion by transmethylation inhibitors.

Three inhibitors of S-adenosylmethionine-mediated transmethylation, 5'-methylthioadenosine (MTA), 2'-deoxyadenosine and sinefungin, inhibited in vitro invasion by a highly invasive clone (Cl-30) of rat ascites hepatoma cells, AH 130 (AH cells). Difluoromethylthioadenosine (DFMTA), a non-metabolizable derivative of MTA, also caused strong inhibition of invasion at concentrations that did not suppress the growth of the tumor cells. Cl-30 cells precultured in methionine-depleted medium showed decreased invasiveness. DFMTA was also effective on the invasion by fibrosarcoma, B16 melanoma and human lung carcinoma cell lines.

Adenosine↗

PubMed1989

In vitro invasion of endothelial cell monolayer by rat ascites hepatoma cells.

To study the tissue preference of invasion, we developed an assay system for the invasion of endothelial cells as a modification of the previously established assay of tumor cell invasion of mesothelial cells. Rat ascites hepatoma cells (AH 130) that had been seeded on a monolayer of cultured endothelial cells penetrated and formed tumor cell colonies under the monolayer. The penetration was time-dependent and the number of penetrated tumor cells and colonies was proportional to the number of tumor cells seeded. Comparison of the in vitro tumor cell invasion of endothelial cell monolayer with that of cultured mesothelial cell layer showed that a clone from the tumor cells (Cl-30) which was highly penetrative into the mesothelial cell layer had only limited ability to penetrate the endothelial cell layer.

Animals↗

PubMed1989

Potentiation of invasive capacity of rat ascites hepatoma cells by transforming growth factor-beta.

The in vitro invasive capacity of poorly invasive cells (W1), which were cloned from rat ascites hepatoma cells (AH 130), was potentiated dose- and time-dependently by pretreating the cells with transforming growth factor-beta (TGF-beta). This potentiation of invasive capacity was completely abolished by anti-TGF-beta antibody. When the treated cells were ip inoculated into rats, the cells extensively invaded the peritoneum, and formed penetrating tumor nodules. The effect of TGF-beta was reversed by subculturing the treated cells without TGF-beta. The potentiation of invasive capacity by TGF-beta might participate in platelet-associated enhancement of tumor cell metastasis.

Animals↗

PubMed1989

Ionophoretic activities of oligopeptide lactones and resin-glycosides in human erythrocytes.

Oligopeptide lactones (theonellapeptolides) isolated from the Okinawan marine sponge Theonella swinhoei and resin-glycosides (merremosides) from the tuber of an Indonesian medicinal plant Merremia mammosa were examined regarding their activities in transporting Na+, K+, and Ca++ ions into human erythrocytes. Each of these lactones, which had been shown, using a supported liquid membrane, to have an ionophoretic effect on the alkali metal ions, transported the ions to a different extent. The ion transporting activities of these compounds were completely lost when the macrocyclic lactone structures were cleaved by sodium methylate. Resin-glycosides with an additional branched glycosyl residue showed much greater ion transporting activities than those without it.

Erythrocytes↗

PubMed1989

Quantitative study on the interface between bone tissue and Blade-vent implants using the image processing system.

Undecalcified histopathologic sections of two titanium blade-vent implants (which had survived for five years in a dog) were made, and image analyses of the bone-implant interface were determined. One implant was inserted conventionally in the right mandible, and the other was inserted shallower than usual in the left mandible, so that the shoulder was located at the same level as the residual bone ridge. Using an image analysis technique, we observed, on the deeper implant, a 0-56% rate of bony contact around the implant and a 71-84% rate of bone-vent occupancy in the vents. With the shallower implant, a 0-46% rate of bony contact and a 26-60% rate of bone-vent occupancy were observed. When the two implants were compared, the deeper implant showed relatively higher bony contact and bone-vent occupancy than its less-submerged control in the five-year study.

Animals↗

PubMed1989

Potentiation and inhibition of tumor cell invasion by host cells and mediators.

A culture model for invasion of rat mesothelial cell layer by rat ascites hepatoma cells has been developed. By using this quantitative model, the preculture with macrophages (0.1 less than macrophage/tumor cell less than 1.0) was found to enhance both the in vitro and in vivo invasive potentials of the tumor cells. This potentiation appears to be mediated partly by oxygen radicals generated by the cocultured macrophages. The in vitro invasive capacity was also augmented by pretreating the tumor cells with TGF-beta or with activated platelets. A factor with anti-invasive potential (IIF) was extracted from rat liver. It inhibited the directed migration but not the growth of the tumor cells and was effective on their in vivo invasion and metastasis, as well.

Animals↗

PubMed1988

Factor from rat liver with antiinvasive potential on rat ascites hepatoma cells.

An acid/ethanol extract of normal rat liver, both in vitro and in vivo, inhibited the invasion by a highly invasive subpopulation of rat ascites hepatoma cells, AH 130 (LC-AH cells). The addition of 10-80 micrograms/ml extract inhibited the formation of penetrated colonies of LC-AH cells underneath the cultured mesothelial cell (M-cell) monolayer. The tumor cells pretreated with the extract showed the diminished colony formation. Preincubation of the extract with plasma membranes prepared from LC-AH cells abolished the effect of the extract, suggesting a binding of the inhibitory entity [tentatively termed as "invasion-inhibiting factor" (IIF)] to the tumor cell surface. The extract did not inhibit the growth of LC-AH cells, but suppressed their directed migration underneath the M-cell monolayer. A concomitant i.p. injection of the extract with LC-AH cells into rats prevented the invasion by tumor cells of the peritoneum and formation of tumor nodules in the peritoneum and mediastinum, indicating that IIF inhibited the tumor cell invasion and metastasis in vivo, as well. Upon ultrafiltration and gel fractionation, about 60% of IIF activity was recovered in the fraction corresponding to the molecular weight in the range of Mr 3000-4000. This activity was heat-stable at 100 degrees C at neutral pH but labile at acidic pH and was inactivated by the treatment with pronase. The rest of the activity of IIF was found in the fraction of more than Mr 25,000.

Animals↗

PubMed1988

Enhancement of metastatic capacity of fibroblast-tumor cell interaction in mice.

A low metastatic clone, G6, was isolated from the B16 melanoma cell line by cloning procedure. When the cells were cultured in vitro with fibroblasts from newborn mice, the lung-colonizing potential of G6 cells was substantially increased. The effect of coculture depended on the number of the fibroblasts. The elevated colonizing potential of G6 cells was reversed to the original low potential by subculturing them for 20 days without the fibroblasts. The culture medium conditioned by G6-fibroblast coculture demonstrated an activity to enhance the lung-colonizing potential of G6 cells, whereas the medium from the culture of fibroblasts alone showed only a little activity. The growth rate and plating efficiency of G6 cells cultured with the fibroblasts or in the conditioned medium did not differ from those of uncocultured G6 cells. The potentiating activity in the conditioned medium was nondialyzable and stable to heating at 80 degrees C for 10 min, but was lost after heating for 10 min at 120 degrees C, or by the treatment with trypsin. These results indicate that the enhancement of lung-colonizing potential of G6 cells could be mediated by a soluble factor(s) released from cocultured fibroblasts.

Animals↗

PubMed1988

Differences between the bony interfaces of titanium and hydroxyapatite-alumina plasma-sprayed titanium blade implants.

Histopathologic study was done to reveal the difference of bony interface in the mandibular bone between titanium blade implants and titanium implants coated with the mixture of hydroxyapatite-alumina by the plasma-spray technique, using the improved undecalcified histologic technique and the image analyzing system. In 4 adult shepherd dogs, the implantation was performed in the molar region of the mandible 2 months after tooth extraction. The coated implants and the non-coated ones were inserted respectively in the mandibles. They were sacrificed on the 5th, 7th, 14th and 28th day postoperatively. In 5-day implant after insertion, granulation tissues or fibrous connective tissues were observed around both implants in bone tissues. In 7-day implant, osteoid tissues regenerated around the apex of both implants, but attached a little to them. In 14-day implant, osteoid tissues or woven bone regenerated around both implants and attached more to the coated implant (approximately 13.7%) than the non-coated one (approximately 6.0%). In 28-day implant, regenerative woven or lamellar bone attached much more to the coated implant (approximately 63.4%) than the non-coated one (approximately 8.8%). Bony interface increased remarkably in the coated implants, chronologically. The results showed that the plasma-sprayed hydroxyapatite-alumina coating was effective for the initial fixation of endosseous dental implants.

Aluminum Oxide↗

PubMed1987

Glycylproline dipeptidyl aminopeptidase and gamma-glutamyl transpeptidase in human hepatic cancer and embryonal tissues.

Changes of glycylproline dipeptidyl aminopeptidase (GPDA) and gamma-glutamyl transpeptidase (gamma-GTP) activities and their subcellular distributions were compared in human hepatic cancer and embryonal tissues. The activity of GPDA in cancer tissues was significantly higher than that found in healthy liver, though there were no significant differences between fetal and adult livers. The placenta, however, had the highest GPDA activity. The activity of gamma-GTP, on the other hand, was increased significantly not only in cancer tissues but also in live tissues adjacent to the tumor, and it was higher in the fetal liver but much lower in the placenta. Subcellular distribution of GPDA was also different from that of gamma-GTP in cancer tissues, especially after postmortem changes. These results suggest the possibility that GPDA has carcinoembryonic characters similar to gamma-GTP, but the mechanisms, whereby serum activities of these two enzymes were increased in hepatocellular carcinoma patients, are different from each other.

Adult↗

PubMed1987

Macrophage potentiation of invasive capacity of rat ascites hepatoma cells.

In vitro and in vivo invasive capacities of rat ascites hepatoma cells (AH 130) that had been cultured on the feeder layers of rat macrophages were examined. The in vitro invasive capacity of the tumor cells was measured by their ability to form tumor cell colonies underneath cultured mesothelial cell monolayers; in vivo invasive capacity was examined by the implantation of the tumor cells into the rat peritoneal cavity. When the tumor cells were precultured on a macrophage feeder layer, the in vitro invasive capacity of the tumor cells increased almost 10 times as much as that of uncocultred control cells. The cocultured tumor cells, when implanted in rat peritoneal cavity, infiltrated extensively in the peritoneum and formed many tumor nodules and enlarged metastatic lymph nodes. Implantation of the uncocultured tumor cells did not develop any macroscopically detectable nodules. The effect of macrophages was reversed by subculturing the cocultured tumor cells without macrophages. Treatment of the tumor cells with the medium conditioned by macrophage culture did not result in the increase in invasive capacity. Almost 50% of the macrophage-mediated enhancement of the in vitro invasive capacity was inhibited by the simultaneous addition of superoxide dismutase and catalase at the time of tumor cell-macrophage coculture.

Animals↗

PubMed1987

[Establishment of an experimental model for tumor cell invasion and potentiation and inhibition of the invasive capacity].

Seeding of rat ascites hepatoma cells (AH 130) on cultured mesothelial cell monolayers resulted in the penetration of single tumor cells and subsequent formation of tumor cell colonies underneath the monolayers. Determination of the number of colonies facilitated quantitative estimation of the in vitro invasive ability, which corresponded well with the in vivo invasive capability of the tumor cells. Preculture of AH 130 cells with macrophages greatly potentiated both the in vitro and in vivo invasive capacities of the tumor cells. This potentiation seems to be mediated by certain species of active oxygen radicals generated by macrophages. Acid/ethanol extract of normal rat liver inhibited both the in vitro and in vivo invasion by the tumor cells. The inhibiting entity in the extract was heat-stable and had a molecular weight in the range of 3.5-10 Kd. It did not suppress tumor cell attachment to mesothelial cell layers, or inhibit tumor cell growth, but selectively impaired the penetration step of the tumor cell invasion through its binding to the tumor cell surface.

Animals↗

PubMed1986

Differential effect of sodium butyrate on cyclic AMP phosphodiesterase activities in butyrate sensitive and resistant mastocytoma cells.

The effect of sodium butyrate on the intracellular cyclic AMP levels and the activities of cyclic AMP-regulating enzymes were examined in two types of mastocytoma p-815 cells in culture: one type (S cell) was sensitive and the other (R cell) was resistant to the induction of differentiation by sodium butyrate. In the presence of sodium butyrate, adenylate cyclase activity increased in both S and R cells to the same degree, whereas the level of cyclic AMP was elevated only in S cells. Cyclic AMP phosphodiesterase activity increased in R cells but not in S cells. Cyclic AMP phosphodiesterase activities of two cell populations differed in their response to sodium butyrate and they seem to have an important role in regulating cellular level of cyclic AMP that might be an important factor in controlling cell differentiation.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1986

Superoxide radical potentiates invasive capacity of rat ascites hepatoma cells in vitro.

Effect of superoxide radical (O2-) produced extracellularly by hypoxanthine (HX) and xanthine oxidase (XO) on invasive capacity of rat ascites hepatoma cells was studied. Invasive capacity was estimated in vitro by counting the number of tumor cell colonies penetrated underneath cultured mesothelial cell monolayer. When the tumor cells had been treated with non-toxic doses of HX and XO, the formation of penetrated colonies increased with increasing concentrations of XO. This increment was completely inhibited by scavengers of active oxygen radicals, superoxide dismutase (SOD) in combination with catalase (CAT) added simultaneously at the time of HX-XO treatment.

Animals↗

PubMed1986

Anchorage-independent cell growth-inhibiting factor(s) from normal rat liver and ascites hepatoma.

Acid/ethanol extracts of normal rat liver and rat ascites hepatoma cells (AH 130) were found to inhibit the epidermal growth factor (EGF)-dependent colony formation of Balb/c 3T3 cells. The extracts did not inhibit the growth of the 3T3 cells in monolayer culture. The inhibitory activities were heat- and acid-stable and were not inactivated by the treatment with pronase, RNase and DNase. Upon ultrafiltration, a considerable fraction of the inhibitory activities were found in the fraction corresponding to the molecular size ranging from 3.5 to 10 Kd, in which no appreciable TGF-beta activity was detected.

Animals↗

PubMed1986

Interaction of rat ascites hepatoma cells with cultured mesothelial cell layers: a model for tumor invasion.

Interactions of rat ascites hepatoma cells with primary cultured layers of rat mesentery-derived cells were studied. The mesentery-derived cells were isolated from rat mesentery and cultured in Eagle's minimum essential medium with a 2-fold concentration of amino acids and vitamins supplemented with 10% calf serum. The primary cultured cells, consisting mainly of mesothelial cells in polygonal shape, forms a "paving stone" sheet. Upon seeding the tumor cells on the mesentery-derived cell layers, three different types of tumor cell growth were observed. Type 1 was the formation of piled-up tumor cell nests on mesothelial cell layers. Type 2 was the formation of flattened tumor cell islands underneath mesothelial cell layers. This island formation was clearly observed under a phase contrast microscope 2 days after the tumor cell seeding. Protrusion of cellular processes of the tumor cells beneath mesothelial cells was occasionally seen. Type 3 was the growth of tumor cells in suspension. These types of tumor cell growth closely resemble those in the peritoneal cavity observed after i.p. implantation of the tumor cells. When the tumor cells recovered from the blood of tumor-bearing rats were seeded, flattened tumor cell islands were formed 15 times more frequently than when the tumor cells isolated from host peritoneal cavity were seeded. Shortly after the appearance of small flattened tumor cell islands, a distinct morphological change of mesothelial cells from polygonal to spindle shape was seen preferentially at the marginal area of the cell layers (a partial retraction of cell edges). The retraction of mesothelial cells was induced not only by seeding the tumor cells but by adding the tumor ascites fluid or the medium conditioned by the tumor cell culture. The morphological change was reversed by changing the culture medium to remove the effectors. These results indicate that the system described in this study can provide a useful model to study tumor cell invasion.

Animals↗

PubMed1984

Extrusion of nuclei of murine suspension culture cells with microtubule poisons.

Microtubule poisons such as colchicine, colcemid and vinblastine caused extrusion of nuclei of murine suspension culture cells (mastocytoma p-815 cells, myeloma PU-3 cells, leukemia M1 cells). Enucleation did not follow spontaneously in most cells, but it did occur when the treated cells were centrifuged in Separate-L gradient. These poisons did not induce nuclear extrusion in cells growing in monolayer (L cells, BALB/c 3T3 cells, SV40-transformed BALB/c 3T3 cells, histiocytoma HC-11 cells). Cytochalasin B (CB) that had been reported to cause nuclear extrusion in the cells cultured in monolayer [1] did not induce the extrusion in the suspension culture cells but inhibited the colchicine-induced nuclear extrusion.

Animals↗