Platelet aggregability and fibrinolytic activity in different phases of menstrual cycle.

Background:- Sexual dimorphism in coronary artery disease (CAD) mortality is attributed to the cardioprotective effects of estrogen.This is reinforced by the observation that incidence of myocardial infarction is higher in menstrual phase, corresponding with low estrogen levels, in people who are predisposed to CAD due to the presence of modifiable risk factors. Cyclical variability of estrogen and progesterone in normal menstruating women may be associated with variability of platelet aggregation and fibrinolytic activity.There exists a delicate balance between fibrinolytic activity and platelet aggregation governing the haemostatic status. Objectives:- Platelet aggregability and fibrinolytic activity were measured and compared during menstrual (1-5 days), follicular ( 9-12 days) and luteal (20-25days) phases of menstrual cycle. Method:- In this cross sectional study of 50 normal menstruating females in age group of 18-35yrs, Platelet aggregability was measured by ADP induced platelet aggregation on a spectrophotometer. Fibrinolytic activity was estimated by euglobulin clot lysis time. Results :- Results were analyzed by students unpaired ‘t’ test. Change in platelet aggregability was found 0.12 ± 0.15, 0.04 ± 0.04 and 0.08 ± 0.07 in menstrual, follicular and luteal phase respectively. Platelet aggregability was found significantly (p < 0.001) higher in menstrual and luteal phases than follicular phase. The mean euglobulin clot lysis time was found 277.6 ± 43.96, 147.6 ± 52.78 and 244.6 ± 59.12 in menstrual, follicular and luteal phase respectively. Fibrinolytic activity was found significantly (p < 0.0001) lower in menstrual and luteal phases than follicular phase. Conclusion :- According to the present study, in both luteal and menstrual phases, not only platelet aggregability was found higher, but fibrinolytic activity was also found lower as compared to follicular phase, thereby pointing towards thrombotic tendency in these phases. Hence, these phases require careful monitoring in women who are susceptible to thrombotic disorders. However, follicular phase with lower platelet aggregability and higher fibrinolytic activity is relatively free from thrombotic risk.

Effect of dauricine on platelet aggregation of patients with acute myocardial infarction / 中国药理学通报

AIM: To investigate the possibility of dauricine (DAU) to inhibit the irreversible platelet aggregation of patients with acute myocardial infarction (AMI). METHODS: Glycoprotein IV (GP IV) and thrombospondin(TSP) levels on the membrane surface of the stationary platelet or platelet activated by thrombin(50,100, 500, 1 000 U·L-1) in 12 patients with AMI were measured with a washed platelet flowcytometric assay and compared with those of the healthy (n = 14). RESULTS: The GP IV, TSP level of stationary platelet and activated platelet in patients with AMI were higher than those in the healthy significantly (P<0.05, 0.01), DAU (50 μmol·L-1) inhibited the GPIV membrane redistribution and the release of TSP from intracellular αgranules induced by thrombin (50 U·L-1, 100 U·L-1, 500 U·L-1) apparently (P<0.05, 0.01), inhibitory effect of DAU was not found in platelets activated with high concentraction of thrombin (1 000 U·L-1). CONCLUSION: The activity and reactivity to thrombin of platelets increased in patients with AMI and DAU may have a blocking effect on the consolidation of platelet aggregation in AMI.

Platelet Aggregability in the Patients with Peripheral Vestibulopathy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Circulatory disturbance to vestibular organ has been regarded as one of the causes that bring about vertigo, and alteration of the platelet function is known to be an important factor inducing circulatory deficit. This study was designed to evaluate platelet aggregability in the patients with peripheral vestibulopathy, and to evaluate difference according to duration of illness. MATERIALS AND METHODS: Platelet aggregation tests to adenosine diphosphate (ADP), ristocetin, epinephrine and collagen were performed in 10 normal subjects and 15 patients with peripheral vestibulopathy. Maximum aggregation rates from aggregation curves were compared between the two groups, and also between the two groups of patients who had different duration of illness. RESULTS: In the patient group, platelet aggregations to ADP, ristocetin and collagen were increased compared to normal subjects and significant differences were found in aggregations to ADP and ristocetin. However, there was no significant difference according to different duration of illness in the patient group. CONCLUSION: These results suggest that platelet aggregability is increased in the patients with peripheral vestibulopathy, and duration of illness does not affect platelet aggregability.

Balneotherapy and Platelet Glutathione Metabolism / 日本温泉気候物理医学会雑誌

Two experiments were performed to clarify the effects of balneotherapy on platelet glutathione metabolism. One experiment, in which healthy men were subjected to water immersion at temperatures of 25°C, 36°C, and 42°C for 10min, showed that the level of platelet lipid peroxides (LPO) tended to increase at 25°C and 42°C, suggesting the presence of oxidative stress at these temperatures. When an antioxidative defense system was induced at these temperatures, the levels of platelet glutathione (GSH), glutathione peroxidase (GPX) and glutathione reductase (GR) activities increased. The other experiment, in which 4 weeks of balneotherapy was applied to type II (non-insulin-dependent) diabetic patients, showed that the level of GSH on admission correlated well with that of fasting plasma glucose (FPG, r=0.692, p<0.050). After 4 weeks of balneotherpy, the level of GSH increased (p<0.01) in well-controlled patients (FPG<150mg/dl) and decreased (p<0.05) in poorly controlled patients (FPG≥150mg/dl), There was a negative correlation between GPX activities and the level of FPG (r=-0.430, p<0.05). After the balneotherapy, the activity increased in five patients, decreased in three patients, and showed no changes in four patients.<br>These results indicate that, in diabetic patients, 1) platelet GSH synthesis is obviously induced in response to oxidative stress, 2) lowered GPX activities suggest an impaired antioxidative defense system, and 3) platelet glutathione metabolism was partly improved by 4 weeks of balneotherapy but depended on the control status of plasma glucose levels. From these findings, we conclude that 1) patients whose platelet antioxidative defense system is damaged such as those with diabetes mellitus should not take hot or cold bath, and that 2) balneotherapy improves platelet glutathione metabolism, leading to normalization of platelet aggregability.