Analgesic Effects of Tetrodotoxin Combined with Acetylsalicylic Acid on Acetic Acid-induced Abdominal Constriction and Formalin Test in Mice

Aim To study the effects of tetrodotoxin （TTX） combined with acetylsalicylic acid （ASA） on nociceptive stimulus in mice. Methods To assess the antinociceptive effects of TTX, ASA or TTX plus ASA, the acetic acid-induced abdominal constriction test and formalin pain test were used. Results TTX （0.5 - 4.0 μg· kg^-1 ） or ASA （25 - 200 mg· kg^-1 ） im produced a significant inhibition of acetic acid-induced abdominal constriction. The median inhibitory doses （ID508） were 2.1 μg· kg^-1 for TTX（ and 64 mg· kg^-1 for ASA. TTX and ASA also showed a dose-dependent inhibition of the second phase response in the formalin pain model, the ID508, being 2.3μg·kg^-1 and 74.2 mg· kg^-1, respectively. The ihteraction between TTX and ASA was synergistic, as evidenced by the fact that （1） when ASA alone compared with the combination of TTX （0.79 μg · kg^-1 or 0.39μg· kg^-1 ） and ASA, the ID508, of ASA reduced from 64.0 mg· kg^-1 to 5.8 mg· kg^-1 or 12.6 mg· kg^-1, and from 74.2 mg· kg^-1 to 7.4 mg· kg^-1 or 13.0 mg· kg^-1 on tile two models of nociceptive tests, respectively; and that （2） synergism in the analgesic effects was shown by isobiolographic analysis. Conclusion TTX, ASA and the combination of the two drags produce analgesic effects in acetic acid-induced abdominal constriction test and formalin-induced pain test. The interactions between TTX and ASA may be useful in developing novel analgesic agents.

果树抗旱保水剂

每年7-9月高温干旱缺水，影响果树果实膨大，造成落果、裂果、小果，降低产量和品质。在缺少水源的果园中，使用化学保水剂、抗蒸腾剂，可节水、防旱，有利于柑桔增产。

Mechanisms underlying aspirin-mediated growth inhibition and apoptosis induction of cyclooxygenase-2 negative colon cancer cell line SW480

AIM： To investigate the effects of aspirin （acetylsalicylic acid） on proliferation and apoptosis of colorectal cancer cell line SW480 and its mechanism. METHODS： Cyclooxygenase （COX）-2 negative colorectal cancer cell line SW480 was treated with aspirin at concentrations of 2.5 mmol/L, 5.0 mmol/L, 10.0 mmol/L for different periods in v/tro. Anti-proliferation effect of aspirin on SW480 was detected by 3-（4,5-dimeth- ylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Cell cycle and apoptosis were observed by flow cytometry （FCM）. Transmission electron microscope （TEM） was used for morphological study. Apoptosis-associated genes were detected by immunohistochemical staining and Western blotting. RESULTS： Aspirin inhibited SW480 proliferation and induced apoptosis in a dose- and time-dependent manner. Treatment with different concentrations of aspirin significantly increased the proportions of cells at the G0/G1 phase and decreased the proportions of cells at the S- and G2/M phases in a concentration-dependent manner. Aspirin not only induced apoptosis but also caused cell necrosis at a high concentration as well. After treatment with aspirin, SW480 cells displayed typically morphological features of apoptosis and necrosis under TEM, and increased the Bcl-2 expression in cells, but the expression of Bax was down regulated. CONCLUSION： Aspirin inhibits proliferation and induces apoptosis of SW480 cells. Its anti-tumor mechanism may arrest cell cycle and shift Bax/Bcl-2 balance in cells.

Role of Helicobacter pylorieradication in aspirin or non-steroidal anti-inflammatory drug users

Helicobacter pylori (H pylori) infection and the use of nonsteroidal anti-inflammatory drugs (NSAIDs) including aspirin at any dosage and formulation represent well-established risk factors for the development of uncomplicated and complicated peptic ulcer disease accounting for the majority of such cases. Although the interaction between H pylori and NSAID/aspirin use in the same individuals was questioned in some epidemiological studies, it has now become widely accepted that they are at least independent risk factors for peptic ulcer disease. According to data from randomized intervention trials, naive NSAID users certainly benefit from testing for H pylori infection and, if positive,H pylori eradication therapy prior to the initiation of NSAID. A similar strategy is also suggested for naive aspirin users, although the efficacy of such an approach has not been evaluated yet. Strong data also support that chronic aspirin users with a recent ulcer complication should be tested for H pyloriinfection and, if positive, receive H pylori eradication therapy after ulcer healing, while they appear to benefit from additional long-term therapy with a proton pump inhibitor (PPI).A similar approach is often recommended to chronic aspirin users at a high risk of ulcer complication. H pylori eradication alone does not efficiently protect chronic NSAID users with a recent ulcer complication or those at a high-risk, who certainly should be treated with long-term PPI therapy, but H pylori eradication may be additionally offered even in this setting. In contrast, testing for H pylorior PPI therapy is not recommended for chronic NSAID/aspirin users with no ulcer complications or those at a low risk of complications.

Effect of pretreatment with aspirin and ticlopidine on the change of platelet aggregability after radiofrequency catheter ablation

Eighty-two patients with supraventricular tachycardia undergoing radiofrequency catheter ablation (RFCA) were studied to observe the inhibition effect of aspirin and ticlopidine on platelet aggregability (PAG) and thromboxane B 2(TXB 2) of the blood samples. Patients were divided into aspirin group A, ticlopidine group B, aspirin+ticlopidine group C and control group D. PAG and TXB 2 were increased clearly after RFCA in all groups (P<0.001). Treatment with aspirin or ticlopidine before operation could reduce the platelet aggregability caused by RFCA and the joint effect of two drugs(change rate of group A:52.51±12.51%; group B:54.78±11.27%;group C: 30.51±10.59%;group D:91.75±21.43%; P<0.05)was studied. The much decreased platelet aggregability after antiplatelet therapy was evidence of the potential benefit of the treatment in preventing thromboembolism after ablation. Pretreatment with aspirin and ticlopidine together is a good way to decrease palatelet aggregability after RFCA.