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T Nakadate

Publications and source records attributed to T Nakadate.

At least 55 records · Page 3Linked to original sources
PubMed1990

Differential effects of various skin tumor-promoting agents on prostaglandin E2 release from primary cultures of mouse epidermal cells.

Prostaglandin E2 (PGE2) release from primary cultures of mouse epidermal cells was markedly stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA), mezerein and 1-oleoyl-2-acetyl-glycerol but not by 4 alpha-phorbol-12,13-di-decanoate in low Ca2+ (50 microM) medium. TPA-evoked PGE2 release was inhibited by mepacrine, indomethacin and H-7 but not by HA1004. These findings suggest that TPA stimulates PGE2 release through activation of protein kinase C, phospholipase A2 and the cyclooxygenase pathway. Of the non-TPA type of tumor promoting agents, i.e. anthralin, chrysarobin, 7-bromomethylbenz[a]anthracene, benzoylperoxide, okadaic acid and palytoxin, only anthralin stimulated PGE2 release. Anthralin-evoked PGE2 release was not inhibited by H-7. In normal Ca2+ (1.8 mM) medium, PGE2 release increased markedly compared to the release in low Ca2+ medium. In normal Ca2+ medium, PGE2 release was stimulated by TPA, anthralin and okadaic acid but not by other tumor promoting agents. In mouse peritoneal macrophages, TPA, palytoxin and okadaic acid stimulated PGE2 release, but other tumor-promoting agents failed to stimulate it. These results suggest that skin tumor promoting agents are not necessarily effective stimulators of prostaglandin production either in macrophages or in epidermal cells, the target cells of skin tumor promotion.

Animals↗
PubMed1990

Anti-tumor promoting action of phthalic acid mono-n-butyl ester cupric salt, a biomimetic superoxide dismutase.

Skin tumor promotion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) was inhibited by a concurrent and topical application of phthalic acid mono-n-butyl ester cupric salt (PAMBCu) in CD-1 mice initiated with 7,12-dimethylbenz[a]anthracene. PAMBCu inhibited TPA-caused epidermal ornithine decarboxylase (ODC) induction and ear edema formation, i.e. skin inflammation. However, neither PAMBCu nor superoxide dismutase (SOD) inhibited TPA-caused ODC induction in primary cultured mouse epidermal cells. 7-Bromomethylbenz[a]anthracene (BrMBA) is known to be a non-TPA type of tumor promoting agent. Epidermal ODC induction and inflammation caused by BrMBA were not inhibited by a concurrent application of PAMBCu. When mice were topically treated twice with PAMBCu, i.e. concurrently with and 7 h after BrMBA treatment, BrMBA-caused ODC induction was markedly suppressed. The same dose regimen of PAMBCu, however, failed to inhibit tumor promotion and inflammation caused by BrMBA. PAMBCu showed SOD-mimetic activity in superoxide generating systems, i.e. xanthine-xanthine oxidase reaction and TPA-stimulated polymorphonuclear leukocytes (PMN). Mono-n-butyl phthalate, which lacks SOD-mimetic activity, failed to inhibit TPA-caused ODC induction and skin inflammation. Therefore, inhibition by PAMBCu of TPA-caused tumor promotion, epidermal ODC induction and inflammation may be attributable to its SOD-mimetic activity. The results also support the contention that a superoxide anion of non-epidermal cell origin, such as PMN and macrophages, plays a role (probably some enhancing role) in in vivo ODC induction and tumor promotion caused by TPA. Failure of PAMBCu to inhibit BrMBA-caused tumor promotion suggests that superoxide anion generation is not involved in the tumor promoting action of this agent and that the anti-tumor promoting action of PAMBCu is dependent on the nature of the tumor promoting agents.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

[Longitudinal analysis of the development of pulmonary function in childhood].

In order to evaluate, longitudinally, the development of pulmonary function in childhood, maximal expiratory flow volume (MEFV) curves, height, and weight of 441 fourth grade school children were measured in 1980, and again two and four years later. The same instruments were used to measure pulmonary function, height, and weight in all three surveys. In addition, pulmonary function tests were performed by the same examiner in all three surveys. Three hundred and twenty five children had acceptable results for MEFV curves at all of three surveys. Two simple linear models were fitted to the distribution of pulmonary function measurements. One has age, height, functional level of the individual child, and the interaction of age and height as explanatory variables. In the other model, the natural logarithm of pulmonary function measurements was considered as a dependent variable, and age, height, and functional level of the individual child were employed as explanatory variables. The models explained the distribution of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and maximal expiratory flows (MEFs) quite well both in males and in females. These results suggest that the development of FVC and FEV1 against height was not linear, and that age was an independent contributor to the development even after adjusting for height. Tracking in the development of MEFs as well as FVC and FEV1 was observed, suggesting that functional development of MEFs for an individual child could be evaluated accurately utilizing percentile curves as in the case of FVC and FEV1.

Adolescent↗
PubMed1989

Inhibition by lipoxygenase inhibitors of 7-bromomethylbenz[a]anthracene-caused epidermal ornithine decarboxylase induction and skin tumor promotion in mice.

7-Bromomethylbenz[a]anthracene (BrMBA) has been shown to have a tumor-promoting action in mouse skin without an initial direct interaction with protein kinase C, which is believed to be a receptor for phorbol ester tumor promoters such as 12-O-tetradecanoylphorbol-13-acetate (TPA). An application of BrMBA to mouse dorsal skin caused epidermal ornithine decarboxylase (ODC) induction in a dose-dependent manner with a peak of activity at 12 h after the application. A single topical application of BrMBA failed to induce mouse ear edema formation, i.e. inflammation. However, repeated applications of BrMBA, i.e. twice a week for 3-4 times, caused a significant edema. Unlike TPA, BrMBA failed to stimulate the superoxide anion generation of rabbit peritoneal polmorphonuclear leukocytes. Lipoxygenase inhibitors such as 3,4,2',4'-tetrahydroxychalcone, nordihydroguaiaretic acid, quercetin and 2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone (AA861) effectively inhibited BrMBA-caused epidermal ODC induction and ear edema formation. In addition, BrMBA-caused skin tumor promotion was also potently inhibited by 3,4,2'4'-tetrahydroxychalcone and quercetin. These results indicate that a mechanism susceptible to lipoxygenase inhibitors plays a role not only in the TPA-caused but also in the BrMBA-caused epidermal ODC induction, skin inflammation and tumor promotion. It seems unlikely that superoxide anion generation is involved in the mechanism of BrMBA-caused skin tumor promotion.

Animals↗
PubMed1989

Differential inhibition by staurosporine, a potent protein kinase C inhibitor, of 12-O-tetradecanoylphorbol-13-acetate-caused skin tumor promotion, epidermal ornithine decarboxylase induction, hyperplasia and inflammation.

The effect of staurosporine on 7,12-dimethylbenz[a]anthracene (DMBA)-initiated and 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted skin papilloma formation was examined in CD-1 mice. A topical application of staurosporine 15 min prior to each TPA treatment resulted in a dose-related inhibition of tumor formation. Staurosporine by itself had no tumor producing activity in DMBA-initiated mice. Staurosporine failed to prevent TPA-induced edema formation, whereas quercetin markedly suppressed it. Staurosporine by itself did not induce a significant edema. Histological studies revealed that staurosporine failed to inhibit TPA-induced inflammation but rather augmented TPA-induced polymorphonuclear leukocyte (PMN) infiltration. Staurosporine by itself induced a slight PMN infiltration 1 h after the drug application, but the effect was only transient. Although staurosporine failed to inhibit the TPA-induced epidermal hyperplasia and DNA synthesis significantly, nuclear atypism of the superficial layer of the epidermis appeared to be less remarkable in staurosporine-pretreated mice. TPA-caused epidermal ornithine decarboxylase (ODC) induction was not inhibited by staurosporine but rather augmented by this agent. TPA enhanced the phosphorylation of 34 kd protein in intact epidermal cells in a concentration-dependent manner. Staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) suppressed the TPA-stimulated phosphorylation of 34 kd protein, but palmitoylcarnitine failed to suppress it. In addition, TPA-stimulated superoxide generation of rabbit peritoneal PMN was potently inhibited by staurosporine. It is possible that TPA induces inflammation, ODC activity, epidermal hyperplasia and tumor promotion through the activation of different type(s) of protein kinase C and staurosporine inhibits only certain type(s) of protein kinase C. Another possible explanation is that the protein kinase C inhibition by staurosporine depends on the nature of the substrate proteins or the intracellular localization of the enzyme.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

The mechanism of skin tumor promotion caused by phorbol esters: possible involvement of arachidonic acid cascade/lipoxygenase, protein kinase C and calcium/calmodulin systems.

12-O-Tetradecanoylphorbol-13-acetate (TPA) has been used as a potent tumor promoter in mouse skin. The mechanisms of TPA actions were studied by using several types of inhibitors. TPA-caused responses in mouse skin such as skin tumor promotion, epidermal ornithine decarboxylase (ODC) induction and skin inflammation were inhibited by various lipoxygenase inhibitors of the arachidonic acid cascade. Lipoxygenase inhibitors also inhibited TPA-caused ODC induction in isolated epidermal cells or cultured epidermal cells. Therefore, it is possible that these drugs inhibit TPA-caused ODC induction in mouse skin by directly acting on epidermal cells. TPA actions were also inhibited by either protein kinase C inhibitors, calmodulin antagonists or calcium blockers. These results suggest that arachidonic acid/lipoxygenase, protein kinase C and calcium-calmodulin systems play essential roles in the mechanism of tumor promotion by TPA.

Animals↗
PubMed1989

Transit time analysis of forced expiration in workers exposed to dust: a cross-sectional study.

Maximal expiratory flow at 25% forced vital capacity (V25), V25 divided by height (V25/HT), and mean transit time (MTT) were calculated from the same forced expiratory maneuver performed in welding workers. The values were compared to determine variations between individuals and changes with age and chest X-ray findings. The results showed that MTT may be a less variable and equally sensitive measurement of the function of peripheral airways as compared with V25 and V25/HT. Its usefulness in the detection of the early changes of pneumoconiosis, however, must be further investigated in a prospective cohort study on workers exposed to various kinds of dust.

Adult↗
PubMed1989

H-7, a protein kinase C inhibitor, inhibits phorbol ester-caused ornithine decarboxylase induction but fails to inhibit phorbol ester-caused suppression of epidermal growth factor binding in primary cultured mouse epidermal cells.

12-O-tetradecanoylphorbol-13-acetate (TPA) induced ornithine decarboxylase (ODC) and suppressed 125I-epidermal growth factor (EGF) binding in primary cultured mouse epidermal cells. TPA (30 nM)-caused ODC induction was almost completely blocked by 30 microM H-7 [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine], a well known protein kinase C inhibitor, but the same concentration of H-7 failed to restore the 125I-EGF binding suppressed by TPA (10 nM). On the other hand, sphingosine, another protein kinase C inhibitor, blocked not only TPA-caused ODC induction but also TPA-caused suppression of 125I-EGF binding. Concentration-response curves of sphingosine for these two TPA-caused cellular responses were almost identical. 1,2-Diacylglycerols such as 1,2-dioctanoylglycerol (30-300 microM) and 1-oleoyl-2-acetylglycerol (OAG) (30-300 microM) mimicked TPA actions. Similar to the case of TPA, suppression of 125I-EGF binding by OAG was barely inhibited by H-7, whereas sphingosine was more effective in inhibiting the OAG-caused suppression of 125I-EGF binding than was H-7. In TPA (50 nM)-pretreated epidermal cells, TPA (10 nM) failed to suppress 125I-EGF binding. H-7 (30 microM) did not affect TPA (30 nM)-caused translocation of protein kinase C. These results clearly demonstrate the differential inhibition by H-7 of the TPA-caused cellular responses and indicate that TPA-caused suppression of 125I-EGF binding to epidermal cells is mediated through protein kinase C function, which is barely inhibited by H-7.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

Comparison of protein kinase C functional assays to clarify mechanisms of inhibitor action.

The effects of inhibitors of protein kinase C on the activities of the intact enzyme, the proteolytically-generated catalytic domain, and [3H]phorbol 12,13-dibutyrate (PDBu) binding were compared in an effort to evaluate this approach for clarifying mechanisms of inhibitor action. Staurosporine, H-7 [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine], and quercetin inhibited the catalytic fragment with similar potencies as for the intact enzyme while having little or no effect on binding, consistent with reports that they are competitive with ATP. Adriamycin, trifluoperazine, and tamoxifen, suggested to disrupt hydrophobic interactions between the regulatory domain of protein kinase C and phospholipid, were all most effective on the intact enzyme. They appear to possess a mixed mechanism, however, inhibiting activity of the catalytic domain with approximately 3-fold lower potencies. Gossypol inhibited intact enzyme, catalytic fragment, and PDBu binding with similar potencies. In light of multiple apparent sites of action for such protein kinase C inhibitors, comparison of their activities on the individual functional domains of the kinase may provide a useful complement to studies with the intact enzyme.

Animals↗
PubMed1988

Palmitoylcarnitine reverses 12-O-tetradecanoylphorbol-13-acetate-induced refractory state for the TPA-caused ornithine decarboxylase induction in mouse epidermis.

When a single topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA) was performed 12 h before the second application, ornithine decarboxylase (ODC) induction by the second application of TPA was markedly suppressed (refractory state). However, at intervals of 96 h between the first and the second application, the ODC activity induced by the second application of TPA was higher (enhanced state) than the activity induced by the single application. When various anti-tumor promoting agents, i.e. p-bromophenacyl bromide, nordihydroguaiaretic acid, quercetin, 1-tosylamide-2-phenylethyl chloromethyl ketone, retinoic acid and palmitoylcarnitine, were applied concurrently with the first TPA application, the ODC induction in the refractory state was restored only by palmitoylcarnitine, but not by other antitumor promoting agents. None of these anti-tumor promoting agents affected the ODC induction in the enhanced state. Stearoylcarnitine also had the restorative effect but was less effective than palmitoylcarnitine. Acetylcarnitine and palmitic acid were not effective. Pretreatment of mice with TPA 12 h or 96 h before the second TPA application resulted in the reduction or the increase in the Vmax values of ODC both for ornithine and pyridoxal-5'-phosphate, respectively. Palmitoylcarnitine restored these reduced Vmax values to the control values. Twelve hours after TPA treatment, the epidermal protein kinase C activity of both cytosol and particulate fractions decreased moderately. At 96 h after TPA application, protein kinase C activities of both cytosol and particulate fractions were fully or at least partially restored to the control levels. Protein kinase C activities both in the cytosol and the particulate fractions tended to be restored by palmitoylcarnitine, but the effect was not always reproducible. The TPA-induced refractory state and the enhanced state for ODC induction appear to result from the changes in the protein kinase C activities caused by TPA. However, it is not known whether such changes in the protein kinase C activities are the major causes for the TPA-induced refractory and/or enhanced state for ODC induction and whether or not the restorative effect of palmitoylcarnitine is due to its modulating action on protein kinase C activity.

Animals↗
PubMed1987

Modulation by palmitoylcarnitine of protein kinase C activation.

Palmitoylcarnitine, a reported protein kinase C inhibitor, enhanced the phorbol ester dependency of the enzyme, augmenting protein kinase C activity in the presence of phorbol esters such as phorbol 12,13-dibutyrate while inhibiting the basal activity measured in the presence of calcium plus phosphatidylserine. Weakly potent phorbol esters such as phorbol 12,13-diacetate and 4-O-methylphorbol 12-myristate 13-acetate were full agonists like phorbol 12,13-dibutyrate for activation of protein kinase C in the presence of palmitoylcarnitine. On the other hand, 1,2-diacylglycerols such as 1,2-diolein were only partially stimulatory. Palmitoylcarnitine did not interfere with the association of protein kinase C with phosphatidylserine, suggesting that its action was on protein kinase C activation per se rather than on priming. A long fatty acid ester, quaternary amine, and anionic charge were needed for the palmitoylcarnitine-like action. Phosphatidylcholine, which possesses these features, partially mimicked the action of palmitoylcarnitine. Palmitoylcarnitine thus appears to be a lipophilic modulator of protein kinase C rather than a simple inhibitor. The results raise the possibility that differences in response between phorbol esters and diacylglycerols may reflect differential ability to activate protein kinase C in the appropriate lipid environment rather than the existence of unique targets for one or the other compound.

Animals↗
PubMed1987

The induction of ornithine decarboxylase caused by 12-O-tetradecanoylphorbol-13-acetate in isolated epidermal cells is inhibited by lipoxygenase inhibitors but not by cyclooxygenase inhibitors.

The effects of lipoxygenase and cyclooxygenase inhibitors on ornithine decarboxylase (ODC) induction by a potent tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA) were examined in vitro in isolated mouse epidermal cells. Lipoxygenase inhibitors such as quercetin, nordihydroguaiaretic acid (NDGA), 3,4,2',4'-tetrahydroxychalcone, 3-amino-1-(3-trifluoromethylphenyl)-2-pyrazoline (BW755C) inhibited the TPA-caused ODC induction. Indomethacin, a selective cyclooxygenase inhibitor, failed to inhibit it. These results suggest that the lipoxygenase inhibitors inhibit TPA-caused epidermal ODC induction in mouse skin at least in part by acting directly on epidermal cells while cyclooxygenase inhibitor inhibits it indirectly by acting on cells other than epidermal cells, e.g. cells which are involved in the prostaglandin-dependent inflammatory process.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1987

Effect of phospholipid on substrate phosphorylation by a catalytic fragment of protein kinase C.

Limited tryptic digestion of protein kinase C purified from mouse brain generated a 36-kDa fragment which no longer required Ca2+ and phospholipid for activity or bound phorbol ester. Under appropriate conditions, the isolated fragment was stable for several months at 4 degrees C or upon freezing and storage at -70 degrees C. Kinetic characteristics of the fragment were similar to those for the intact protein kinase. Although the fragment did not require phospholipid for activity, anionic phospholipids affected the extent of its activity in a pH-, substrate-, and substrate concentration-dependent manner. This effect appeared to be due to complex formation between the phospholipid and substrate. The catalytic fragment thus permits detection of a second point of interaction of phospholipid with the protein kinase C system in addition to the already described phospholipid regulatory domain.

Calcium↗
PubMed1986

Some properties of lipoxygenase activities in cytosol and microsomal fractions of mouse epidermal homogenate.

Lipoxygenase activity in microsomal fraction of mouse epidermal homogenate was characterized in comparison with cytosol lipoxygenase activity. The major activity was identified as 12-lipoxygenase in microsomal fraction as well as in cytosol fraction by the analyses with high-performance liquid chromatography and gas chromatography-mass spectrometry. Apparent Km values of cytosol and microsomal 12-lipoxygenase for arachidonic acid were 5.0 microM and 6.2 microM respectively. Apparent Vmax values were 14 pmol/min/mg protein for the cytosol enzyme and 32 pmol/min/mg protein for the microsomal enzyme. Net activities of cytosol and microsomal 12-lipoxygenase were 214 and 109 pmol/min/g wet tissue, respectively. Both cytosol and microsomal lipoxygenase activities were neither dependent on calcium nor ATP. Carbon monoxide failed to affect these enzyme activities. There were considerable differences either in the effect of glutathione or in the sensitivities toward several lipoxygenase inhibitors, indicating that the cytosol and the microsomal 12-lipoxygenase activities are derived from two different enzymes. Alternatively, the differences could be attributable to the different microenvironments of these enzymes.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

Inhibition of 12-O-tetradecanoylphorbol-13-acetate-mediated epidermal ornithine decarboxylase induction and skin tumor promotion by new lipoxygenase inhibitors lacking protein kinase C inhibitory effects.

Both 2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone (AA861) and 3,4,2',4'-tetrahydroxychalcone inhibited 12-lipoxygenase of mouse epidermis. The IC50 of AA861 and 3,4,2',4'-tetrahydroxychalcone for epidermal 12-lipoxygenase were 1.9 and 0.2 microM, respectively. These agents showed very weak inhibitory actions on epidermal cyclooxygenase, with the potency of inhibition for cyclooxygenase less than 1/50 of that for lipoxygenase. Induction of epidermal ornithine decarboxylase by 12-O-tetradecanoylphorbol-13-acetate (TPA; 10 nmol/mouse) was potently inhibited by these agents in a dose-dependent manner (1-30 mumol/mouse). TPA (5 nmol/mouse)-induced skin tumor formation was also strongly suppressed by these agents (15 mumol/mouse). Both AA861 and 3,4,2',4'-tetrahydroxychalcone failed to inhibit partially purified epidermal protein kinase C activity. These results support the proposed involvement of lipoxygenase product(s) of arachidonic acid in TPA-induced skin tumor promotion.

Animals↗
PubMed1986

Inhibition of 12-O-tetradecanoylphorbol-13-acetate-induced epidermal ornithine decarboxylase activity and tumor promotion by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) in mouse skin.

N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) inhibited epidermal ornithine decarboxylase (ODC) induction caused either by 12-O-tetradecanoylphorbol-13-acetate (TPA) or teleocidin in CD-1 mice. Inhibitory effect of W-7 on TPA-caused ODC induction was also observed in 7,12-dimethylbenz[a]anthracene (DMBA)-initiated skin and even after repetitive TPA treatment. TPA-induced skin tumor promotion was also suppressed by W-7. Meanwhile, W-7 showed only slight inhibitory effects on calcium-activated, phospholipid-dependent protein kinase (protein kinase C) activity of mouse epidermis stimulated either by Ca2+ or TPA in the presence of phosphatidylserine. Thus, it is unlikely that the anti-ODC-inducing and anti-tumor-promoting actions of W-7 are due to its inhibitory effect on protein kinase C. It may be possible that a calmodulin-mediating process is involved in the mechanism of epidermal ODC induction and tumor promotion caused by tumor promoters such as TPA and teleocidin.

Animals↗