Inhibitory effects of ticlopidine on platelet function as assessed by three different methods

Synthesis and Molecular Docking of New Thiophene Derivatives as Lactate Dehydrogenase-A Inhibitors

BACKGROUND & OBJECTIVE

A series of novel derivatives possessing the thiophene moiety were synthesized using ethyl 5'-amino-2,3'-bithiophene-4'-carboxylate as the starting material.

METHODS

The new synthesized derivatives were screened as lactate dehydrogenase (LDH) inhibitors. LDH plays an important role in glucose metabolism in cancer cells and can affect tumor genesis and metastasis.

RESULTS

3-Substituted p-tolylthieno[2,3-d]pyrimidin-4(3H)-ones 4 were the most potent inhibitors in this study compared to Galloflavin reference drug.

CONCLUSION

Molecular docking studies on the Human Lactate Dehydrogenase active site were carried out on the synthesized compounds and the MolDock scores ranged between -127 to -171.

Impairment of platelet retention rate in patients with severe aortic valve stenosis

BACKGROUND

Recent reports revealed the presence of acquired von Willebrand syndrome type 2A in patients with aortic valve stenosis (AS). von Willebrand factor (vWF) has been shown to play a vital role in platelet adhesion. Therefore, we measured the platelet retention rates, which reflect platelet adhesion, in patients with severe AS.

METHODS

In addition to echocardiography, routine blood screening tests were performed and the platelet retention rates were measured using collagen-coated bead columns in 21 patients with severe AS and in 21 control subjects.

RESULTS

Patients with severe AS showed the maximum aortic valve pressure gradients of 110.9±22.7 mmHg, and effective orifice areas of 0.59±0.20 cm2. The results of routine blood tests in patients with severe AS were comparable to those of control subjects; however, the platelet retention rates in the AS patients (7.3±5.0%) were significantly lower than those in control subjects (30.5±11.8%, p<0.001). A significant negative correlation was observed between maximum aortic valve pressure gradients and platelet retention rates (r = -0.81, p<0.001). In 8 patients with severe AS, the platelet retention rates increased from 5.8±3.6% to 16.0±2.4% after aortic valve replacement (p<0.001).

CONCLUSION

These findings suggest that impairment of platelet retention rate is seen in almost all patients with severe AS. Clinicians should be aware of the possibilities of vWF-mediated platelet dysfunction and bleeding tendency in patients with severe AS.

Association of recurrent cerebral infarction with adenosine diphosphate- and collagen-induced platelet aggregation in patients treated with ticlopidine and/or aspirin

Although the platelet aggregation test is the most common method for evaluating response to antiplatelet therapy, little is known about the association of recurrent cerebral infarction with platelet aggregation in the presence of various different antiplatelet drugs. We prospectively evaluated adenosine diphosphate (ADP)- and collagen-induced platelet aggregation and followed the incidence of recurrent infarction in patients categorized into 3 groups based on treatment; aspirin (n = 144), ticlopidine (n = 100), and aspirin + ticlopidine (n = 96). The patients in each treatment group were stratified into quartiles according to platelet aggregation, and the association of recurrent infarction with platelet aggregation was investigated. ADP-induced platelet aggregation values were significantly lower in the ticlopidine group and the aspirin + ticlopidine group compared with the aspirin group (P < .001), and collagen-induced platelet aggregation values were significantly lower in the aspirin group and the aspirin + ticlopidine group compared with the ticlopidine group (P < .001). In the aspirin group, the recurrence rate was somewhat higher in the higher aggregation quartiles than in the lower aggregation quartiles of 2 μg/mL collagen, the differences were not statistically significantly (P = .243). In the ticlopidine group, the recurrence rate was significantly higher in the lower aggregation quartiles compared with the higher aggregation quartiles of 1 μmol/L ADP (P = .025). No tendencies were found in the aspirin + ticlopidine group. Although the study is limited by its small sample size, the results suggest a possible difference between aspirin therapy and ticlopidine therapy in the pattern of association of recurrent infarction with platelet aggregation.