Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Baraprost sodium (sodium (+/-)-(1R*,2R*,3aS*,8bS*)-2,3,3a.8b- tetrahydro-2-hydroxy-1-[(E)-(3S*)-3-hydroxy-4-methyl-1-octen-6- 1H-cyclopenta[b]benzo-furan-5-butyrate, TRK-100) is a novel stable epoprostenol (prostaglandin I2, PGI2) analogue having antiplatelet and vasodilating actions. Its effect on platelet aggregation in whole blood ex vivo and platelet suspension in vitro, formation of cyclic AMP(cAMP), production of malondialdehyde(MDA), and 45Ca++-influx into platelets were studied in rats. Oral administration of TRK-100 (0.3-1 mg/kg) showed a dose-dependent inhibition of platelet aggregation induced by ADP and collagen in whole blood and also inhibited in vitro thrombin-induced aggregation of platelet suspension in the presence or absence of external Ca++. Oral TRK-100 (0.3-3 mg/kg) dose-dependently increased plasma cAMP levels and this action was confirmed in vitro with platelet rich plasma in the presence or absence of theophylline. 45Ca++-influx into platelets stimulated by thrombin was dose-dependently inhibited by TRK-100 (3-100 nmol/l). TRK-100 (3-100 nmol/l) also suppressed MDA production induced by thrombin in platelet suspension but not that induced by arachidonic acid. From these results, TRK-100 which is orally active was suggested to exert its antiplatelet action through the increase of cAMP in platelets by activation of adenylate cyclase, concomitantly followed by the inhibition of Ca++-influx and thromboxane A2 formation.
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PMID:Studies on the antiplatelet effect of the stable epoprostenol analogue beraprost sodium and its mechanism of action in rats. 254 30

TRK-100 is a chemically stable analogue of prostacyclin and effective in inhibiting platelet aggregation when orally administered in experimental animals. In the present study we compared the potency of TRK-100 with those of PGI2 and PGE1 to cause an activation of adenylate cyclase activity in rat and human platelet membranes. TRK-100 was half as effective as PGI2, and 10 times more effective than PGE1 in both platelet membranes. TRK-100 also induced an activation of phosphodiesterase activity when directly added to intact platelets probably as a feedback mechanism of intracellular cAMP level like PGI2 did. TRK-100 would mimic PGI2 in the regulation of cAMP metabolism.
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PMID:Effects of TRK-100, a stable prostacyclin analogue, on regulation of cyclic AMP metabolism in platelets. 254 34

We had previously detected a transforming oncogene, designated PTC, in 25% of 20 papillary thyroid carcinomas. In order to characterize further the transforming activity of this tumour histotype, a new panel of tumour specimens from 16 patients was analysed by using a modified calcium phosphate-DNA coprecipitation transfection protocol. Tumour DNA from 10 patients (62%) displayed a transforming activity due to activation of three different oncogenes identified in four cases as PTC, in four cases as TRK, and in two cases as N-RAS. The same structural alterations of PTC and TRK (gene rearrangements) as well as of N-RAS (point mutation) detected in the NIH3T3 transformants, were also found in the original tumour DNAs, thus indicating that their activation was not due to transfection procedures. Since both PTC, a novel rearranged form of RET, and TRK display a tyrosine protein kinase activity, it is proposed that the activation of this class of oncogenes is specifically involved in the pathogenesis of papillary thyroid cancer.
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PMID:High frequency of activation of tyrosine kinase oncogenes in human papillary thyroid carcinoma. 259 68

We investigated the influence of the diabetic state on the contractile response of longitudinal segments of isolated mesenteric vein to prostanoids and leukotriene (LT), and the contribution of the vascular endothelium to modulation of the contractile response was determined. The normal mesenteric vein and de-endothelialized veins of normal (ddY), diabetic KK-CAy and streptozotocin ddY mice (150 mg/kg, i.v., 6 weeks) were used. In the diabetic state, the contractions produced by noradrenaline (60 microM), high K+ solution (143.4 mM), and the thromboxane A2 analogue U-46619 (29 nM-29 mM) were not affected, and LTD4 (0.1 nM-1 microM)-induced contraction was suppressed. Contractions induced by prostaglandin (PG) E2 (0.2 microM-2 mM), PGF2 alpha (0.3 microM-0.3 mM) and the prostacyclin derivatives PGI2-Na (10-100 microM) and TRK-100 (0.2 microM-2 mM) were significantly enhanced in the presence of an intact vascular endothelium, but not in de-endothelialized segments. The increase in PGF2 alpha (0.28 mM) contractions was dependent on age (correlation coefficient r = 0.36, significant difference, P less than 0.05) and blood glucose (r = 0.88, significant difference, P less than 0.01), but was independent of obesity. The contractile response to PGD2 (0.3-0.9 mM) was enhanced in both intact and de-endothelialized segments. These results indicate that the diabetic state affects prostanoid responses in an endothelium-dependent manner, except for the PGD2 response, which is independent of the endothelium.
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PMID:Diabetes-induced enhancement of prostanoid-stimulated contraction in mesenteric veins of mice. 262 93

Binding of beraprost sodium (sodium dl-4-[(1R,2R,3aS,8bS)-1,2,3a,8b-tetrahydro-2-hydroxy-1-[(3S, 4RS)- 3-hydroxy-4-methyl-oct-6-yne-(E)-1-enyl] -5- cyclopenta[b]benzofuranyl]butyrate, TRK-100), a new potent antithrombotic agent, to washed platelets of humans and rats was studied. [11-3H]-TRK-100 binding was rapid, reversible, saturable, and highly specific. Scatchard analysis of concentration-dependent binding to human platelets revealed a single class of specific binding sites with an equilibrium dissociation constant (Kd) of 133 nmol/l and a maximal concentration of binding sites (Bmax) of 46 fmol/10(8) platelets (275 sites/cell). Similar binding was observed on rat platelets. The Kd and Bmax were 66 nmol/l and 124 fmol/10(8) platelets (750 sites/cell), respectively. Competitive studies indicated that TRK-100 was 1.5 times less active than prostacyclin (epoprostenol, PGI2), but was 3 times more potent than PGE1 in displacing [3H]-TRK-100 from the binding sites on rat platelets. PGE2, PGD2, PGF2 alpha, and pinane thromboxane A2, a stable thromboxane A2 analogoue, had no affinity for the binding sites. The relative affinity of the four enantiomers of TRK-100--APS-314d, 315d, 3141 and 3151--for the binding sites was 100: 14: less than 1: less than 1, respectively. These results suggest that TRK-100 is a useful tool for studying biological roles of PGI2 as well as for use as an antithrombotic agent since TRK-100 mimics its actions via specific interaction with PGI2 receptors.
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PMID:Specific binding of the new stable epoprostenol analogue beraprost sodium to prostacyclin receptors on human and rat platelets. 266 58

Effect of beraprost sodium (TRK-100), a stable PGI2 analog, on experimentally induced skin ulcer was studied in rats. An experimental skin ulcer was developed by intradermal injection of acetic acid. Injection of glacial acetic acid to the skin in the left hind leg instep of rats resulted in the necrosis of the skin, and a skin ulcer developed in 3 days. The ulcer area reached its peak on the 5th day, and recovered to its control level within 4 weeks. The effects of TRK-100 and indomethacin on the ulcer were tested. TRK-100 showed suppressive effects on the development of the ulcer. A dose of 30 micrograms/kg (p.o.) accelerated healing of the ulcer when scored macroscopically on the 9th or 15th day. At a dose of 100 micrograms/kg (p.o.), it reduced the development of the ulcer and accelerated healing with statistical significance from the 5th day and thereafter. Indomethacin also reduced the development of the ulcer and accelerated healing with statistical significance from the 7th day and thereafter. These results suggest TRK-100 may be effective on the inhibition of the development and accelerated the healing of the skin ulcer formed in various pathological states.
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PMID:Effect of beraprost sodium (TRK-100) on acetic acid-induced skin ulcer. 267 30

The effects of the active principles of crude ginger (a traditional Sino-Japanese medicine), the gingerols, on the contractile responses to eicosanoids were compared using isolated mouse and rat blood vessels. Leukotrienes (LT) C4 and D4, a thromboxane (TX) A2 derivative (U-46619), prostaglandins (PG) F2 alpha, PGI2-Na, PGE2, the stable PGI2 derivative TRK-100, and PGD2 induced contraction in longitudinal segments of mouse mesenteric veins in that order of potency. Exogenous arachidonic acid and PGE1 did not cause contraction. The mesenteric veins also contracted in response to noradrenaline (NA) and phenylephrine (PhE), but not to clonidine. The gingerols alone relaxed the muscle transiently and then augmented the response to PGF2 alpha, PGE2, PGI2-Na, and TRK-100, but suppressed the response to PGD2, U-46619, LTC4, LTD4, NA and PhE. (+/-)-[6]-Gingerol also potentiated the PGF2 alpha-induced contraction in longitudinal segments of rat mesenteric vein and vena cava, but inhibited it in circular segments of rat aorta and longitudinal segments of mouse mesenteric arteries. These results showed that (+/-)-[6]- and (+/-)-[8]-gingerols potentiated the contraction induced by prostanoids (except PGD2) and inhibited that produced by PGD2, TXA2, and LT, suggesting the modulation of eicosanoids-induced responses by (+/-)-[6]- or (+/-)-[8]-gingerol.
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PMID:Modulation of eicosanoid-induced contraction of mouse and rat blood vessels by gingerols. 276 Nov 27

Effect of TRK-100, a stable PGI2 analog, on platelet function was tested in vitro and ex vivo. TRK-100 at the dose range of 0.5-300 nM inhibited platelet aggregation induced by arachidonic acid, adenosine 5'-diphosphate and collagen in several species including human platelets. The potency of TRK-100 was 1/2 to 1/5 that of PGI2. The effect was strong in human and cat platelets. In conscious rabbits and rats, oral TRK-100 at the dose range of 0.1-1 mg/kg inhibited ex vivo platelet aggregation up to 80% in the rat and 70% in the rabbit, and the effect lasted over 5 hr. However, in both species, the effect on blood pressure was minimal. In anesthetized rabbits, inhibition of platelet aggregation was the same level as in the conscious animal, but blood pressure depression was observed. Cyclic AMP levels of human platelets, 2 min after incubation, was elevated up to 2.4 microM/10(9) platelets by 100 ng/ml of PGI2 and 1.5 microM by 100 ng/ml of TRK-100. It was shown that TRK-100 has a potent antiplatelet effect both in vitro and ex vivo in many species through elevation of platelet cAMP. These results suggest that TRK-100 may be a potential oral antithrombotic drug.
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PMID:The in vitro and ex vivo antiplatelet effect of TRK-100, a stable prostacyclin analog, in several species. 284 29

Helically cut strips of dog coronary and mesenteric arteries of proximal and distal portions contracted in response to angiotensin (ANG) II in a dose-dependent fashion. The contractions were greater in the distal portions than in the proximal portions. Mesenteric arteries responded to the peptide with a greater contraction than coronary arteries. The peptide-induced contraction was suppressed by treatment with saralasin and was potentiated by indomethacin; magnitudes of the potentiation were similar in coronary and mesenteric arteries and in proximal and distal portions. Concentrations of TRK-100, a stable analog of PGI2, equipotent to those of PGI2 released by ANG II, estimated from dose-response curves for TRK-100 and enhancement by indomethacin of ANG II-induced contractions, did not differ in proximal and distal portions. It appears that differences in the contractile response to ANG II depend on heterogeneity in ANG II receptors responsible for the arterial contraction, but not on differences in the PGI2 generation via ANG II receptor activation.
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PMID:Comparison of the response to angiotensin II of isolated dog coronary and mesenteric arteries of proximal and distal portions. 304 21

We evaluated the effect of a stable synthetic prostacyclin analogue, TRK-100, on the microcirculatory derangement occurring in feline pial vessels with endothelial damage after middle cerebral artery occlusion. Fifteen adult cats were divided into an untreated group (Group 1, n = 8) and a treated group (Group 2, n = 7). Thirty minutes after 10 minutes of ultraviolet irradiation, which selectively damaged endothelium in the pial vessels, the middle cerebral artery was occluded in both groups and maintained for 30 minutes. In Group 2, 50 ng/kg/min TRK-100 was continuously infused intravenously following ultraviolet irradiation. In both the pial arteries and veins, platelet aggregate adhesion to the endothelium with subsequent thrombus formation was significantly (p less than 0.01 and p less than 0.05, respectively) inhibited during middle cerebral artery occlusion in Group 2 compared with Group 1. Similarly, blood flow stasis in the pial veins was effectively prevented in Group 2 during occlusion. Furthermore, the pial artery diameter returned to the control level during the late period of occlusion, whereas in Group 1 the pial artery remained constricted. Our data suggest that TRK-100 can prevent microcirculatory derangement in the acute stage of ischemic stroke.
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PMID:Stable prostacyclin analogue preventing microcirculatory derangement in experimental cerebral ischemia in cats. 265 89


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