Vitamin K1 injection induces severe dose-related anaphylactoid reactions and overdose for the treatment of vitamin K deficiency. We aimed to find an optimal and small dose of vitamin K1 injection to treat vitamin K deficiency and avoid anaphylactoid reactions in animal. Rats were administered a vitamin K-deficient diet and gentamicin to establish vitamin K deficiency model. Behaviour tests were performed in beagle dogs to observe anaphylactoid reactions. The results showed an increased protein induced by vitamin K absence or antagonist II (PIVKA-II) levels, a prolonging of prothrombin time (PT) and activated partial thromboplastin time (APTT) and a decrease in vitamin K-dependent coagulation factor (F) II, VII, IX and X activities in the model group. In vitamin K1 0.01 mg/kg group, the liver vitamin K1 levels increased fivefold and the liver vitamin K2 levels increased to the normal amount. Coagulation markers PT, APTT, FVII and FIX activities returned to normal. Both in the 0.1 and 1.0 mg/kg vitamin K1 groups, coagulation functions completely returned to normal. Moreover, the amount of liver vitamin K1 was 40 (0.1 mg/kg) or 100 (1.0 mg/kg) times as in normal. Vitamin K2 was about 4 (0.1 mg/kg) or 5 (1.0 mg/kg) times as the normal amount. There was no obvious anaphylactoid symptom in dogs with the dose of 0.03 mg/kg, which is equivalent to the dose of 0.01 mg/kg in rats. These results demonstrated that a small dose of vitamin K1 is effective to improve vitamin K deficiency and to prevent anaphylactoid reactions, simultaneously.
The Chinese herbal medicine Tianma (Gastrodia elata) has been used for treating and preventing primary headache over thousands of years, but the exact pharmacological mechanism of the main bioactive ingredient gastrodin remains unclear. In present study, the effects of gastrodin on calcitonin gene-related peptide (CGRP) and phosphorylated extracellular signal-regulated kinase1/2 (pERK1/2) expression were observed in rat trigeminal ganglion (TG) after in vitro organ culture to explore the underlying intracellular mechanism of gastrodin on primary vascular-associated headache. CGRP-immunoreactivity (CGRP-ir) positive neurons count, positive area, mean optical density and integrated optical density by means of immunohistochemistry stain were compared at different concentrations of gastrodin, which was separately co-incubated with DMEM in SD rat TG for 24 hours. Only at 5 or 10 mmol L(-1) concentration, gastrodin demonstrated significantly concentration-dependent reduction of CGRP-ir (+) expression and its action closed to 1.2 mmol L(-1) sumatriptan succinate. While at 2.5, 20, and 40 mmol L(-1) concentration, gastrodin did not show remarkable effects on CGRP-ir (+) expression. The optimal concentration of gastrodin (5 and 10 mmol L(-1)) similarly inhibited CGRP-mRNA expression level separately compared with 1.2 mmol L(-1) sumatriptan succinate and 10 micromol L(-1) flunarizine hydrochloride, which was quantitatively analyzed by real-time PCR (RT-PCR). pERK1/2 level was examined by Western blotting after co-cultured with optimal concentration of gastrodin and effective specific ERK1/2 pathway inhibitors PD98059, U0126. The result indicated that gastrodin significantly reduced pERK1/2 protein actions similarly to ERK1/2 pathway specific blockade. It suggests ERK1/2 signaling transduction pathway may be involved in gastrodin intracellular mechanism. This study indicates gastrodin (5 and 10 mmol L(-1)) can remarkably reduce CGRP-ir (+) neuron, CGRP-mRNA and pERK1/2 expression level in cultured rat TG, with its actions similar to the effective concentration of sumatriptan succinate, flunarizine hydrochloride and specific ERK1/2 pathway blocker. The intracellular signaling transduction ERK1/2 pathway may be involved in the gastrodin reducing CGRP up-regulation in rat TG after organ culture.
Purpose: Absolute bioavailability (F) is calculated as the ratio of the area under the plasma drug concentration-time curve (AUC) between extravascular administration and intravenous injection. However, as distribution of a drug after intravenous administration does not reach an equilibrium in the body during the distribution phase, the plasma drug concentration at this phase does not reflect the total amount of drug in the body. The goal of this paper was to analyze the insufficiencies of the method for calculating on absolute bioavailability and to propose a modification to improve the calculation. Methods: Literature reporting absolute bioavailability published during 1983-2014 was searched for ten drug candidates. Plasma drug concentrations representing the amount of drug in the body were then calculated at each time point during the distribution phase according to the plasma drug concentration-time relationship during the elimination phase. Results: The AUC values based on the distribution equilibrium drug concentrations following intravenous injection were 75%±11% of the actually measured drug concentrations in the literature. The absolute bioavailability values in the literature were 76%±12% of the actual bioavailability based on the AUCs from distribution-equilibrium drug concentrations. Conclusions: The present method underestimates the absolute drug bioavailability and should be modified to represent the data more accurately. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
Cigarette smoking is a strong cardiovascular risk factor and endothelin (ET) receptors are related to coronary artery diseases. The present study established an in vivo secondhand smoke (SHS) exposure model and investigated the hypothesis that cigarette smoke induces ET receptor upregulation in rat coronary arteries and its possible underlying mechanisms.Rats were exposed to SHS for 200 min daily for 8 weeks. The coronary arteries were isolated and examined. The vasoconstriction was studied by a sensitive myograph. The expression of mRNA and protein for receptors was examined by real-time PCR, Western blot and immunofluorescence. Compared to fresh air exposure, SHS increased contractile responses mediated by endothelin type A (ET(A)) and type B (ET(B)) receptors in coronary arteries. In parallel, the expression of mRNA and protein for ET(A) and ET(B) receptors of smoke exposed rats were higher than that of animals exposed to fresh air, suggesting that SHS upregulates ET(A) and ET(B) receptors in coronary arteries in vivo. Immunofluorescence staining showed that the enhanced receptor expression was localized to the smooth muscle cells of coronary arteries. The protein levels of phosphorylated (p)-Raf-1 and p-ERK1/2 in smoke exposed rats were significantly higher than in control rats, demonstrating that SHS induces the activation of the Raf/ERK/MAPK pathway. Treatment with Raf-1 inhibitor GW5074 suppressed SHS-induced enhanced contraction mediated by ET(A) receptors, and inhibited the elevated mRNA and protein levels of ET(A) and ET(B) receptors caused by SHS. The results of correlation and regression analysis showed that phosphorylation of Raf and ERK1/2 were independent determinants to affect protein expression of ET(B) and ET(A) receptors.Cigarette smoke upregulates ET(B) and ET(A) receptors in rat coronary artery, which is associated with the activation of the Raf/ERK/MAPK pathway.
The severe adverse reaction to vitamin K1 injection is always remarkable and is thought to result from anaphylaxis. Paradoxically, however, some patients administered vitamin K1 injection for the first time have adverse reactions. Using beagle dogs, the present study tested the hypothesis that the response to vitamin K1 is an anaphylactoid reaction. The results showed that serious anaphylaxis-like symptoms appeared in beagle dogs after the administration of vitamin K1 injection for the first time. The plasma histamine concentration increased, and blood pressure decreased sharply. After sensitization, dogs were challenged with vitamin K1 injection and displayed the same degree of symptoms as prior to sensitization. However, when the vitamin K1 injection-sensitized dogs were challenged with a vitamin K1-fat emulsion without solubilizers such asTween-80, the abnormal reactions did not occur. Furthermore, there was no significant change in the plasma immunoglobulin E concentration after vitamin K1 challenge. Following treatment with vitamin K1 injection, the release of histamine and β-hexosaminidase by rat basophilic leukemia-2H3 cells as well as the rate of apoptosis increased. The Tween-80 group displayed results similar to those observed following vitamin K1 injection in vivo. However, the dogs in the vitamin K1-fat emulsion group did not display any abnormal behavior or significant change in plasma histamine. Additionally, degranulation and apoptosis did not occur in rat basophilic leukemia-2H3 cells. Our results indicate that the adverse reaction induced by vitamin K1 injection is an anaphylactoid reaction, not anaphylaxis. Vitamin K1 injection induces the release of inflammatory factors via a non-IgE-mediated immune pathway, for which the trigger may be the solubilizer.
The main vitamin K-deficient model, minidose warfarin, is different from the pathological mechanism of vitamin K deficiency, which is a shortage of vitamin K. The objective of this study was to establish a new method of vitamin K-deficient model combining a vitamin K-deficient diet with the intragastrical administration of gentamicin in rats. The clotting was assayed by an automated coagulation analyser. The plasma PIVKA-II was assayed by ELISA. The vitamin K status was detected by an HPLC-fluorescence system. In the diet- and gentamicin-induced vitamin K-deficient 14-day group, the rats had undetected vitamin K1 and vitamin K2 in the liver and a prolonged APTT. In the 21-day group, there was also a prolonged PT and a decrease of the FIX activities. In the 28-day group, the undetected vitamin K1 and vitamin K2, the prolonged PT and APTT, and the decrease of the FII, FVII, FIX, and FX activities prompted the suggestion that there were serious deficiencies of vitamin K and vitamin K-dependent coagulation in rats. It is suggested that the diet- and gentamicin-induced vitamin K-deficient 14-day or 21-day model can be used for studies related to the status of vitamin K. The vitamin K-deficient 28-day model can be applied to research involving both the status of vitamin K and of vitamin K-dependent coagulation. In conclusion, the combination of a vitamin K-deficient diet with the administration of gentamicin results in a useful model of vitamin K-deficieny.
Hydrogen sulphide (H2S) exhibits a dual modulation of isolated artery tension. This study investigated the vasoconstrictive effect of sulphur sodium hydride (NaHS), a donor of gaseous H2S, on rat coronary artery.The contractile response of isolated arteries was recorded using a wire myograph. Fluo-3/AM was used to load vascular smooth muscle, and intracellular calcium was determined using confocal laser microscopy. The protein expression of Rho kinase was examined using Western blot.NaHS induced concentration-dependent contractions of rat coronary artery, and the contraction reached approx. 65% of 60 mm KCl-induced contraction. The NaHS-induced contraction was elevated following the removal of endothelium or the use of the nitric oxide synthase inhibitor L-NAME. The cyclooxygenase inhibitor indomethacin reduced NaHS-induced contraction. The Rho kinase inhibitor Y-27632 significantly attenuated NaHS-induced vasoconstriction. Furthermore, NaHS elevated the protein expression of Rho kinase. NaHS-induced contraction was completely abolished in a Ca(2+)-free solution and suppressed by the Ca(2+) influx blocker nifedipine (100 nm). NaHS also significantly increased the change rate of Ca(2+) fluorescence intensity. However, treatment with a Cl(-)/HCO(3-) exchanger blocker, K(+) channel blockers, the mitogen-activated protein kinase inhibitor U-0126 or cyclic adenosine monophosphate did not affect contraction. Species-dependent differences in NaHS-induced vasoconstriction were observed because these effects were only modest in dog coronary artery and absent in rabbit coronary artery.NaHS induces the contraction of rat coronary artery, which is dependent on the activation of Ca(2+) influx. Rho kinase likely participates in the vasoconstriction.
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