Biomedical subjects

E Abe

Publications and source records attributed to E Abe.

At least 109 records · Page 6Linked to original sources

PubMed1991

Granulocyte-macrophage colony-stimulating factor is a major macrophage fusion factor present in conditioned medium of concanavalin A-stimulated spleen cell cultures.

In 1983, we reported that the conditioned medium (CM) of spleen cell cultures treated with Con A greatly induced fusion of mouse alveolar macrophages within 2 to 3 days at a very high rate of more than 80% (Proc. Natl. Acad. Sci. USA 80:5583, 1983). In the course of examining macrophage fusion factors (MFF) present in Con A-CM, we found that IL-4 induced fusion of alveolar macrophages with a time course similar to that induced by Con A-CM. However, the maximal fusion rate induced by IL-4 (4 ng/ml) was about 35%. Furthermore, the fusion induced by Con A-CM was blocked only partially by adding IL-4 antibody, indicating that there are unknown MFF other than in Con A-CM. Of several other cytokines produced by Con A-stimulated spleen cells, IL-6 (20 ng/ml), IFN-gamma (45 ng/ml) and granulocyte-macrophage (GM)-CSF (10 ng/ml) greatly potentiated the fusion induced by 4 ng/ml of IL-4. The assay of these cytokines in Con A-CM proved that it contained 0.44 +/- 0.04 ng/ml of IL-4, 1.0 +/- 0.24 ng/ml of IL-6, 9.1 +/- 0.07 ng/ml of IFN-gamma, and 11.6 +/- 1.66 ng/ml of GM-CSF. When the potentiating effects of IL-6, IFN-gamma and GM-CSF on macrophage fusion were examined in the presence of 0.4 ng/ml of IL-4, only GM-CSF increased the fusion rate to the maximal level induced by Con A-CM at its physiologic concentration (10 ng/ml). The macrophage fusion induced by Con A-CM was greatly suppressed by adding antibody against GM-CSF. GM-CSF had a biphasic effect on growth and fusion, depending on its dose levels used: 0.01 to 0.1 ng/ml increased proliferation without inducing fusion and 10 ng/ml preferentially induced fusion. There was a negative relationship between macrophage growth and fusion. IL-4 was a potent inhibitor of proliferation of macrophages induced by GM-CSF. These results clearly indicate that GM-CSF is a major MFF present in Con A-CM.

Animals↗

PubMed1991

The specific production of the third component of complement by osteoblastic cells treated with 1 alpha,25-dihydroxyvitamin D3.

A 190 kDa protein was purified from conditioned media of mouse marrow-derived stromal cell (ST2) cultures treated with 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) and identified as the third component of mouse complement (C3). Northern and Western blot analysis revealed that the production of C3 by ST2 and primary osteoblastic cells was strictly dependent on 1 alpha,25(OH)2D3, but the production by hepatocytes was not. Adding 1 alpha,25(OH)2D3 together with mouse C3 antibody to bone marrow cultures greatly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like multinucleated cells. Adding C3 alone induced no TRAP-positive cell formation. These results suggest that, in bone tissues, C3 is specifically produced by osteoblasts in response to 1 alpha,25(OH)2D3 and somehow involved in inducing differentiation of bone marrow cells into osteoclasts in concert with other factors produced by osteoblasts in response to 1 alpha,25(OH)2D3.

Acid Phosphatase↗

PubMed1991

Reversal effect of DM-9384 on scopolamine-induced acetylcholine depletion in certain regions of the mouse brain.

The effect of a new cognition enhancer, DM-9384, N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, on regional acetylcholine (ACh) levels and against scopolamine-induced ACh depletion was examined in mouse brain. In addition, the effects of DM-9384 were compared with those of oxiracetam, physostigmine and tacrine. Independent administration of DM-9384 (1, 3, 10 or 30 mg/kg, PO) or oxiracetam (10 or 50 mg/kg, PO) to mice had no effect on the ACh level in the hippocampus, frontal cortex, amygdala and striatum. Nevertheless, in all brain regions, pretreatment with DM-9384 significantly reduced the depletion of ACh induced by scopolamine (0.5 mg/kg, IP) in a nondose-related bell-shaped manner. By contrast, oxiracetam attenuated the effect of scopolamine in the hippocampus, frontal cortex and striatum but not in the amygdala. Physostigmine (0.2 mg/kg, SC) significantly increased ACh levels and reversed the scopolamine-induced ACh depletion in all brain regions. Unlike physostigmine, tacrine (10 mg/kg, PO) increased ACh levels in the striatum but not in the other regions. Tacrine reversed the effect of scopolamine in the hippocampus, amygdala and striatum, but not in the frontal cortex. In the present study, DM-9384 more effectively inhibited scopolamine-induced depletion of ACh levels than the other agents tested. The results obtained indicate that the protective action of DM-9384 against scopolamine-induced amnesia is due to its ability to reverse the ACh depletion.

Acetylcholine↗

PubMed1991

The enhancement of the hypomotility induced by small doses of haloperidol in the phase of dopaminergic supersensitivity in mice.

Dopaminergic supersensitivity in mice was induced by pretreatment with a single injection of haloperidol (4.8 mg/kg). After the pretreatment, further treatment with haloperidol (0.6 or 0.01 mg/kg) was made at varying intervals, and catalepsy, locomotor activity and homovanillic acid (HVA) were measured. The intensity of the supersensitivity was evaluated by enhanced apomorphine (1 mg/kg)-induced climbing behavior. Supersensitivity was displayed on the 2nd and the 4th day. The cataleptogenic effect of haloperidol (0.6 mg/kg) was significantly weakened on the 1st, 2nd and 4th days. The motor inhibitory effect of haloperidol (0.01 mg/kg) increased on the 1st, 2nd and 4th days. Homovanillic acid was measured in the striatum and the prefrontal cortex on the 2nd day. Haloperidol (0.6 mg/kg) increased the concentrations of HVA in both regions of the brain. The increase in the concentrations of HVA in the striatum was blunted after the pretreatment, but such tolerance did not develop in the prefrontal cortex. Haloperidol (0.01 mg/kg) did not influence the concentration of HVA in both regions. These results suggest that the behavioral effect of a small dose of haloperidol may be enhanced, rather than reduced, in the phase of supersensitivity.

Animals↗

PubMed1991

Transcriptional regulation of the production of the third component of complement (C3) by 1 alpha,25-dihydroxyvitamin D3 in mouse marrow-derived stromal cells (ST2) and primary osteoblastic cells.

We have purified a 190-kDa protein produced by mouse marrow-derived stromal cells (ST2) in response to 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] and unequivocally identified it as mouse complement C3 (C3). In this study we examined the regulation by 1 alpha,25-(OH)2D3 of C3 production in ST2 cells at both the transcriptional and translational levels. 1 alpha,25-(OH)2D3 greatly increased the protein production of C3 at 24 h, and it attained a maximum at 72 h. C3 mRNA stimulation by 1 alpha,25-(OH)2D3 was initiated at 12 h and reached a maximum at 48 h. 1 alpha,25-(OH)2D3 increased the expression of C3 mRNA dose-dependently, ranging from 10(-10)-10(-8) M. The increase in the C3 production in response to 1 alpha,25-(OH)2D3 appeared to occur at a transcriptional level, since actinomycin-D completely inhibited both mRNA expression and protein production of C3 induced by 1 alpha,25-(OH)2D3. Besides 1 alpha,25-(OH)2D3, local bone-resorbing agents, such as interleukin-1 alpha, tumor necrosis factor-alpha, and lipopolysaccharides, also stimulated the expression of C3 mRNA, not only in ST2 cells, but also in primary osteoblastic cells. C3 production by hepatocytes occurred regardless of the presence or absence of 1 alpha,25-(OH)2D3. These results clearly indicate that 1 alpha,25-(OH)2D3 tissue-specifically regulates the synthesis of C3 in bone. Bone C3 may play an important role in bone metabolism.

Animals↗

PubMed1991

[A simple multiple maze test to estimate learning and memory in mice: application to the effect of scopolamine on learning and memory].

The apparatus consists of a home cage, a maze cage and a starting box. A maze with four right-middle-left decisions was placed in the maze cage. The starting box was attached and a water tap was placed at an area corresponding to the entrance of the maze. The exit of the maze and the home cage are connected with a tunnel. Food was placed in the home cage. 1) Mice were housed for 10 hr a day in the apparatus and then removed to another cage for fasting. One trial a day was carried out after fasting for more than 12 hr. In each trial, a mouse was put at the starting box, and then the number of errors (entering a blind alley) and the time until the mouse reached the home cage were counted. The mouse passed through the maze with a small number of errors and time. 2) Administration of scopolamine (0.125-0.5 mg/kg, i.p.) to a mouse that had mastered the maze transiently disturbed the maze performance dose-dependently. 3) Mice were housed for 4 hr a day. Scopolamine (0.25 mg/kg, i.p.) was administered either before or after the housing. Scopolamine disturbed the maze performance in the case of both procedures. These results suggest that the method is useful for estimating the memory in mice.

Animals↗

PubMed1990

Interleukin 1 regulates the expression of osteopontin mRNA by osteoblasts.

Osteopontin is a matrix protein which belongs to the integrin superfamily and is involved in cell adhesion. In the present study, we examined the regulation of the mRNA expression of osteopontin by interleukin 1 alpha (IL-1 alpha) in osteoblasts. IL-1 alpha greatly increased the steady-state level of osteopontin mRNA in both a mouse osteoblastic cell line (MC3T3-E1) and mouse primary osteoblast-like cells. The increase in the osteopontin mRNA expression by IL-1 alpha was dose-dependent at a range of 0.004-0.2 nM. This was most likely due to an increase in the transcriptional rate, not to an increase in the stability of osteopontin mRNA. The in vitro nuclear transcription experiment showed that IL-1 alpha-treated MC3T3-E1 cells increased the synthesis of osteopontin mRNA. Besides IL-1 alpha, tumor necrosis factor alpha (TNF-alpha), lipopolysaccharides (LPS) and 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) increased the osteopontin mRNA expression in both the clonal osteoblasts (MC3T3-E1) and the primary osteoblast-like cells. In response to such bone-resorbing agents, primary osteoblast-like cells expressed osteopontin mRNA much more strongly than primary fibroblast-like cells isolated from mouse calvaria. Both IL-1 alpha and 1 alpha,25(OH)2D3 greatly increased the production of 68 and 62 kDa phosphoproteins in conditioned media of MC3T3-E1 cell cultures, which probably correspond to osteopontin. These results suggest that osteopontin plays an important role in bone remodeling, in particular bone resorption.

Animals↗

PubMed1990

IL-6 is produced by osteoblasts and induces bone resorption.

To examine the possible involvement of IL-6 in bone metabolism, a mouse osteoblastic cell line (MC3T3-E1) and primary osteoblast-like cells from fetal mouse calvaria were cultured with several systemic and local bone-resorbing agents and their expression of IL-6 mRNA was determined. Local bone-resorbing agents such as IL-1 alpha, IL-1 beta, TNF-alpha, and LPS greatly induced IL-6 mRNA expression in both MC3T3-E1 cells and primary osteoblast-like cells. Parathyroid hormone slightly increased expression of IL-6 mRNA in primary osteoblast-like cells but not in MC3T3-E1 cells. Neither IL-6 nor 1 alpha,25-dihydroxyvitamin D3 increased expression of IL-6 mRNA in either of the osteoblast-like cells. In agreement with the expression of IL-6 mRNA, biologically active IL-6 was produced in response to the treatment with IL-1 alpha, TNF-alpha, and LPS in MC3T3-E1 cells. Adding IL-6 dose dependently stimulated the release of 45Ca from prelabeled fetal mouse calvaria. Simultaneously adding suboptimal concentrations of IL-6 and IL-1 alpha induced bone resorption cooperatively. In accord with the increase in the release of 45Ca by IL-6, there were three times as many osteoclasts in the bone sections of calvaria cultured with IL-6 for 5 days as in the controls. IL-6 slightly suppressed alkaline phosphatase activity and collagen synthesis in MC3T3-E1 cells. These results indicate that IL-6 is also produced by osteoblasts, preferentially in response to local bone-resorbing agents, and it induces bone resorption both alone and in concert with other bone-resorbing agents.

Alkaline Phosphatase↗

PubMed1990

Effect of a continuously applied compressive pressure on mouse osteoblast-like cells (MC3T3-E1) in vitro.

Bone metabolism is often affected by a variety of mechanical forces, but the cytological basis of their action is not known. In this study, we examined the effect of a continuously applied compressive pressure (CCP) on the growth and differentiation of clonal mouse osteoblast-like cells (MC3T3-E1) cultured in a specifically devised culture chamber. The gas phase of the chamber was maintained at a pressure of 2 atmospheres (atm) above ambient (3 atm total, 3.1 kg/cm2; 3.0 x 10(5) Pa) by continuously infusing a compressed mixed gas (O2: N2:CO2 = 7.0%:91.3%:1.7%). The pO2, pCO2, and pH in the culture medium at 37 degrees C under 3 atm were maintained at the same levels as those under 1 atm. MC3T3-E1 cells were cultured in alpha-minimal essential medium containing 10% fetal bovine serum under either 3 atm in the CCP culture chamber or 1 atm in an ordinary CO2 incubator. Alkaline phosphatase activity, a marker of osteoblasts, was greatly suppressed by the CCP treatment. The inhibition of alkaline phosphatase activity was rapidly restored when the cells were transferred to an ordinary CO2 incubator under 1 atm, indicating that the inhibition of alkaline phosphatase activity by CCP is reversible. Cell growth was not altered under CCP. The CCP treatment greatly increased the production and secretion of prostaglandin E2 (PGE2). Adding either conditioned medium from the CCP culture or exogenous PGE2 to the control culture under 1 atm suppressed alkaline phosphatase activity dose-dependently. The CCP treatment also suppressed collagen synthesis and calcification. These results suggest that CCP causes the cells to produce and secrete PGE2, which, in turn, inhibits differentiation of osteoblasts and the concomitant calcification.

Animals↗

PubMed1990

Fusion of mouse alveolar macrophages induced by 1 alpha,25-dihydroxyvitamin D3 involves extracellular, but not intracellular, calcium.

We have reported that the active form of vitamin D3, 1 alpha, 25-dihydroxy-vitamin D3 [1 alpha, 25(OH)2D3], directly induces the fusion of mouse alveolar macrophages (Abe et al: Proc. Natl. Acad. Sci. USA 80:5583-5587, 1983). The fusion process can be divided into two phases: the 1 alpha,25(OH)2D3-dependent priming phase (0-18 hr) and the calcium-dependent progression phase (18-72 hr) (Jin et al: J. Cell. Physiol. 137:110-116, 1988). In the present study, we examined the role of calcium in the progression phase of macrophage fusion induced by 1 alpha,25(OH)2D3. Macrophages pretreated with 1 alpha,25(OH)2D3 for 48 hr in a low-calcium (0.13 mM) medium began to fuse quickly 30 min after the culture medium was switched to a normal calcium (1.85 mM) medium. Of various cations tested, calcium was the most effective in inducing fusion, followed by strontium and manganese. Magnesium, potassium, and sodium had no effect. Calcium ionophores such as A23187 and ionomycin did not induce fusion in the low-calcium medium, nor did they potentiate fusion in the media containing higher concentrations of calcium. The intracellular concentration of free Ca2+, measured by a fluorescent method using fura-2 AM, was 116 +/- 1 nM in the macrophages pretreated with 1 alpha,25(OH)2D3 for 48 hr in the low-calcium medium. When calcium chloride was added to the assay system at a final concentration of 1.85 mM, the cytosolic free Ca2+ concentration did not increase appreciably (from 116 to 144 nM). But the macrophages began to fuse quickly when CaCl2 was added. In contrast, adding ionomycin increased cytosolic free Ca2+ from 116 to 440 nM, but no fusion occurred. These results clearly indicate that the extracellular, but not the intracellular, calcium is involved in the progression phase of the fusion of mouse alveolar macrophages primed by 1 alpha,25(OH)2D3.

Animals↗

PubMed1990

Effects of 24-hr fasting on methamphetamine- and apomorphine-induced locomotor activities, and on monoamine metabolism in mouse corpus striatum and nucleus accumbens.

The effects of 24-hr fasting on the vertical (VMA) and horizontal (HMA) locomotor activities, on cage climbing activity and on brain monoamine-related substances, were examined using male ddY mice. Both the VMA and HMA increased with fasting, but not the cage climbing activity. Methamphetamine (2 mg/kg, SC) increased the VMA and HMA in both the feeding and fasting mice, whereas with apomorphine (0.1 mg/kg, SC) both decreased. Furthermore, pretreatment with haloperidol (0.025 mg/kg, SC) showed no influence on the methamphetamine-induced VMA increase in both the feeding and fasting mice. However, pretreatment with haloperidol inhibited the methamphetamine-induced HMA increase in both the feeding and fasting mice and showed a higher level of HMA in fasting mice than in feeding mice. When measuring brain monoamine-related substances, the DA, NE, 5-HT, and 5-HIAA levels in the corpus striatum increased, whereas the 3-MT levels decreased. The monoamine levels in the nucleus accumbens of fasting mice were the same as those in feeding mice, except for a decrease of the 3-MT level. These results suggest that the locomotor activity in fasting mice may be increased by a change in the sensitivity of dopaminergic neurons in the corpus striatum.

Animals↗

PubMed1990

The effect of arsenic trioxide on brain monoamine metabolism and locomotor activity of mice.

The arsenic trioxide (AsT) content, and monoamine levels in the cerebral cortex, hippocampus, hypothalamus and corpus striatum were determined in mice administered AsT (3 and 10 mg/kg) for 14 days. The vertical and horizontal motor activity was also examined. The AsT content in discrete brain areas differed but was clearly dose-dependent. Metabolites of norepinephrine and dopamine increased in the cerebral cortex, hippocampus and hypothalamus and decreased in the corpus striatum in AsT-treated mice. Metabolites of 5-hydroxytryptamine increased in all the discrete brain areas. The vertical and horizontal motor activity was increased by AsT at 3 mg/kg and decreased by AsT at 10 mg/kg. These results show that AsT modifies CNS metabolism and function at low doses. AsT penetrates the blood-brain barrier to cause these effects.

Administration, Oral↗

PubMed1990

[Blood pressure changes in children during minor oral surgery].

The purpose of this study was to evaluate the influence of minor surgery conducted in the oral cavities of children. Changes in blood pressure and pulse during minor surgery were measured using a Pulse-Wave Korotokoff Sound Record Meter GP-303S (PARAMA). The subjects consisted of 28 children (15 boys and 13 girls) who underwent minor surgery at the pediatric dental clinic of Iwate Medical University. An examination of 16 of the 28 children to determine the relationship between their physique, personality, and blood pressure was made. The following results were obtained: 1) The maximum blood pressure formed a peak at the time of the impacted supernumerary teeth extraction. This was more conspicuous in boys than in girls. The pulse rose to the highest values with the infiltration of the anesthesia, the incision, and stripping. However, no significant values based on sex difference were demonstrated. 2) The maximum blood pressure changed more intensely during surgery in boys than in girls. This was distinctly observed during extraction of the impacted supernumerary tooth. 3) Both the maximum blood pressure and pulse increased with the progress of the surgery. After the surgery, it returned nearly to the presurgical level. With extraction of a supernumerary tooth and marsupialization, the return of the blood pressure to the preoperative level was more delayed in boys than in girls. 4. The changes in blood pressure and pulse seemed to be mostly induced by mental disquietude and stress such as anxiety and fear of surgery. 5. The physique and personality were related to the changes in blood pressure and pulse during minor surgery in the oral cavity.

Anesthesia, Dental↗

PubMed1989

Electric fields stimulate DNA synthesis of mouse osteoblast-like cells (MC3T3-E1) by a mechanism involving calcium ions.

A cell culture system was designed to study the effect of an electric field on bone cells. This system subjected cultured bone cells to a series of high-voltage pulses at varying amplitudes of electric field without changing the ion concentrations of the culture medium. When mouse osteoblast-like cells (MC3T3-E1) were stimulated for 5 min to 20 hr by an electric field (3.19 kV/m, 3 msec, 10 Hz pulses), DNA synthesis was greatly increased. The stimulation occurred only during the growth phase. The electric field also increased incorporation of 45Ca into the cells, but it did not stimulate cAMP production. Adding calcium ionophore A23187 stimulated both 45Ca uptake and DNA synthesis, but dibutyryl cAMP did not stimulate either of them. These results suggest that the electric field stimulates the DNA synthesis of growing osteoblasts by a mechanism involving calcium ions.

Animals↗

PubMed1989

Spermidine-dependent proteins are involved in the fusion of mouse alveolar macrophages induced by 1 alpha,25-dihydroxyvitamin D3 and interleukin 4.

We have reported that 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] directly induces fusion of mouse alveolar macrophages by a mechanism involving protein synthesis (H. Tanaka et al., 1984, FEBS Lett. 174, 61). While examining further the mechanism of the fusion, we found that polyamines, most likely spermidine, are involved as an important intracellular mediator of the 1 alpha,25(OH)2D3 action in inducing protein synthesis, which in turn induces fusion of macrophages (T. Hayashi et al., 1986, J. Bone Miner. Res. 1, 235). In this study, spermidine-dependent proteins responsible for inducing fusion were examined by electrophoresis of [35S]methionine-labeled proteins. 1 alpha,25(OH)2D3 increased synthesis of 14 proteins at 24 h after the addition, before it initiated fusion at 36 h. When spermidine synthesis was inhibited by adding methylglyoxal bis(guanylhydrazone) (MGBG), the enhanced synthesis in 9 of the 14 proteins induced by 1 alpha,25(OH)2D3 was greatly diminished with a concomitant inhibition of fusion. Further addition of spermidine restored the synthesis of these 9 proteins and the fusion as well. The synthesis of 3 of the 9 proteins was similarly induced by interferon-gamma, retinoic acid, or lipopolysaccharides, which induced activation but not fusion of macrophages. The apparent molecular weights of the remaining 6 proteins were 142K, 98K, 78K, 60K, 50K, and 42K. Recombinant mouse interleukin 4 (IL-4) also induced fusion of alveolar macrophages by a spermidine-dependent mechanism, and it increased the synthesis of 5 proteins (172K, 98K, 78K, 53K, and 50K). These results suggest that 3 spermidine-dependent proteins (98K, 78K, and 50K) are involved in the fusion of mouse alveolar macrophages induced by 1 alpha,25(OH)2D3 and IL-4.

Animals↗

PubMed1988

A differentiation-inducing factor produced by the osteoblastic cell line MC3T3-E1 stimulates bone resorption by promoting osteoclast formation.

We have reported that the differentiation-inducing factor (DIF) is present in conditioned medium of mouse osteoblast-like cell (MC3T3-E1) cultures. In the present study, the DIF from conditioned medium of MC3T3-E1 cells was partially purified and its biologic activity was examined. The DIF was purified by monitoring the induction of phagocytic activity of mouse myeloblastic leukemia cells (M1). The DIF induced differentiation of not only M1 cells but also mouse myelomonocytic cells (WEHI-3). Furthermore, the DIF increased the in vitro bone-resorbing activity and the osteoclast number in mouse calvaria. The increases were inhibited by the addition of either salmon calcitonin or indomethacin. When mouse bone marrow cells were cultured with the DIF for 8 days, formation of osteoclast-like multinucleated cells was stimulated dose dependently. The DIF from MC3T3-E1 cells appeared to be different from interleukin-1 (IL-1), tumor necrosis factor (TNF), and transforming growth factor beta (TGF-beta). These results suggest that the DIF partially purified from osteoblast-like cell cultures stimulates osteoclastic bone resorption by promoting differentiation and fusion of osteoclast progenitors to form multinucleated osteoclasts.

Animals↗

PubMed1988

Calcium is essential in the fusion of mouse alveolar macrophages induced by 1 alpha,25-dihydroxyvitamin D3.

We have reported that the active form of vitamin D3, 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3], directly induces activation and fusion of mouse alveolar macrophages (Abe et al., 1983, 1984). The activated state appeared to be a prerequisite to the fusion of macrophages. Macrophages began to fuse 36 hr after adding 1 alpha,25(OH)2D3; the fusion rate attained a maximum of 70-80% at 72 hr. During the course of further investigating the mechanisms of fusion induced by the vitamin, we found that the calcium ion is closely involved in the fusion process of macrophages induced by 1 alpha,25(OH)2D3. When alveolar macrophages were cultured with 1 alpha,25(OH)2D3 in medium with graded concentrations (0.13-1.85 mM) of calcium, the fusion rate went down in parallel with the decrease of medium calcium. Neither calcium ionophore A23187 nor 12-O-tetradecanoylphorbol-13-acetate (TPA) induced fusion of freshly isolated macrophages, but the two compounds greatly promoted fusion of the macrophages pretreated for 18 hr with 1 alpha,25(OH)2D3. The vitamin effect for the first 18 hr was similar, irrespective of the medium calcium concentration. In contrast, millimolar amounts of calcium were essential in the subsequent period of incubation(18-72 hr) for inducing fusion. The activation of macrophages measured by the induction of cytotoxicity and the enhancement of glucose consumption by 1 alpha,25(OH)2D3 occurred similarly, irrespective of the medium calcium concentration. These results clearly indicate that the fusion process of alveolar macrophages induced by 1 alpha,25(OH)2D3 can be divided into two phases: 1) the calcium-independent priming phase (0-18 hr) and 2) the calcium-dependent progression phase (18-72 hr). 1 alpha,25(OH)2D3 is necessary only in the priming phase; A23187 and TPA can be substituted for 1 alpha,25(OH)2D3 in the progression phase.

Animals↗

PubMed1988

Alteration in growth, cell morphology, and cytoskeletal structures of KB cells induced by epidermal growth factor and transforming growth factor-beta.

Long-term biological effects of epidermal growth factor (EGF), insulin, insulin-like growth factor-I (IGF-I), and transforming growth factor-beta (TGF-beta) were examined with human epidermoid carcinoma KB cells. EGF inhibited the growth of KB cells in both serum-containing and serum-free synthetic media by reducing the growth rate and by lowering the saturation density. The cells cultured with EGF showed relatively high motility and grew dispersely as single cells, whereas the cells cultured in the absence of EGF grew in clusters. Although TGF-beta itself did not inhibit the growth of KB cells, it augmented the growth inhibition by EGF. TGF-beta also affected the cell morphology. In the presence of TGF-beta, the cells became flattened and actin stress fibers were well developed compared to those cultured in its absence. The effects of EGF on growth, cell motility, and cell morphology were reversible. Tyrosine phosphorylation of EGF receptors was continuously observed for at least 50 h in the presence of EGF. TGF-beta did not increase the phosphorylation induced by EGF. These results suggested that signals continuously transmitted through EGF receptors caused the changes in cell growth and morphology and that TGF-beta did not act on the cells by modulating binding of EGF to its receptors or activation of the receptor kinase. In contrast to EGF and TGF-beta, neither insulin nor IGF-I affected cell morphology or growth, although KB cells express their receptors and the receptor kinases were also continuously activated during exposure of the cells to insulin or IGF-I.

Actin Cytoskeleton↗