There is some controversy regarding the effect of general inhalation anesthesia on platelet function. In 20 patients undergoing long operations over 3 hours, and anesthetized with either nitrous oxide-oxygen and enflurane (A group) or nitrous oxide-oxygen and halothane (B group), we could not find any clinically significant impairment of coagulation. Platelet functions were consecutively evaluated on the samples collected at preinduction, during anesthesia (3 hours) and at postoperation (24 hours) using an aggregometer and several aggregating agents including ADP, epinephrine, collagen and ristocetin. There were no statistically significant changes between the maximum aggregation rate of preinduction and that duirng anesthesia in either group.
Adenosine Diphosphate ; Anesthesia ; Anesthesia, Inhalation ; Anesthetics, Inhalation* ; Blood Platelets* ; Collagen ; Enflurane ; Epinephrine ; Halothane ; Humans ; Inhalation* ; Ristocetin

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.
Adenosine Diphosphate ; Blood Platelets* ; Collagen ; Epinephrine ; Humans ; Platelet Aggregation ; Ristocetin ; Vertigo

BACKGROUND: The purpose of this study is to investigate the prevalence of impaired platelet responsiveness to epinephrine in healthy subjects. Also, we compared the platelet aggregability in response to various agonists in normal population. METHODS: A total of 156 healthy subjects aged 21 to 57 years were investigated for the evidence of impaired responsiveness to epinephrine. Aggregometer PACKS-4 (Platelet Aggregation Chromogenic Kinetic System-4, Helena, Beaumont, USA) was used for platelet function test. Aggregating agonists (Helena Haemostasis Systems, UK) used in the study were consisted of ADP (10 micrometer), collagen (10 microgram/mL), epinephrine (300 micrometer) and ristocetin (1500 microgram/mL). Population showing platelet aggregability with more than 60% activity was classified as normal group, while aggregability with less than 20% as impaired responsiveness. RESULTS: Of 156 healthy subjects, 20.5% (32/156) showed impaired responsiveness, while 33.9% (53/156) revealed decreased aggregability with the activity of less than 60% to epinephrine. The mean of maximal percent aggregating activity for collagen was 90.5+/-11.4% and that of epinephrine was 66.5+/-34.4%. The mean aggregation activity (84.4+/-11.8%) for ADP in subjects showing normal response to epinephrine was significantly higher, compared with that (65.7+/-16.2%) of impaired responsiveness group to epinephrine (P<0.01). CONCLUSION: Impaired responsiveness to epinephrine, which is observed in healthy subjects, appears to be a kind of normal variant reaction. And this abnormality is not considered to be associated with any evident bleeding disorders.
Adenosine Diphosphate ; Blood Platelets* ; Collagen ; Epinephrine* ; Hemorrhage ; Platelet Aggregation ; Platelet Function Tests ; Prevalence* ; Ristocetin

OBJECTIVE: To investigate the effect of protein kinase A (PKA) activation on aggregation funetion of platelets in vitro. METHODS: The peripheral blood of healthy adults were collected, and the washed platelets were gained from collected peripheral blood. The washed platelets were treated with PKA activator Forskolin, then the platelet aggregation was induced by using Ristocetin, Thrombin, Collagen and ADP respectively, the platelet aggregation level was detected by the platelet aggregator. RESULTS: Compared with the controls, 5 μmol/L forskolin significantly inhibited ADP and collagen-induced platelet aggregation (P＜0.001), and showed mild inhibiting effect on Thrombin-induced platelet aggregation (P＜0.05). 2.5-10 μmol/L forskolin significantly inhibited ADP and Collagen -induced platelet aggregation (P＜0.001); but not showed significantly inhibitory effects on Ristocetin-induced platelet aggregation (P＞0.05). CONCLUSION PKA activation inhibits agonists-induced platelet aggregation.
Blood Platelets ; Cyclic AMP-Dependent Protein Kinases ; Humans ; Platelet Aggregation ; Platelet Aggregation Inhibitors ; Ristocetin ; Thrombin

We performed platelet aggregation test in sixty three patients (54 ; cerebral infarction, 9 ; transient ischemic attack) who were randomly treated with aspirin 300mg/day or dipyridamole 150mg/day, singlely or in combination or ticlopidine 500mg/day to evaluate the inhibitory effect of commonly used antiplatelet agents on platelet aggregation. All patients had normal baseline platelet aggregation responses to 4 stimuli ; adenosine diphosphate, epinephrine, collagen and ristocetin. Our study showed no inhibitory response to platelet aggregation at least 7 days after antiplatelet administration in 41.1% (14/34) of aspirin group, 9.5% (2/21) of ticlopidine group, and 100% (8/8) of dipyridamole group. In all of the 9 patients with normal aggregation response to aspirin therapy, platelet aggregation test was converted to inhibitory response by ticlopidine. In contrast, in all of the 2 patients with normal aggregation response to ticlopidine therapy, platelet aggregation test was converted to inhibitory response by aspirin. This study confirms previous findings of platelet inhibition by ticlopidine and aspirin in patients with ischemic cerebrovascular disease. And these results suggest that dipyridamole do not inhibit platelet aggregation in vivo.
Adenosine Diphosphate ; Aspirin ; Blood Platelets* ; Cerebral Infarction ; Collagen ; Dipyridamole ; Epinephrine ; Humans ; Infarction ; Platelet Aggregation Inhibitors* ; Platelet Aggregation* ; Ristocetin ; Ticlopidine

BACKGROUND: Although apoptosis occurs in nucleated cells, studies show that this event also occurs in some anucleated cells such as platelets. During storage of platelets, the viability of platelets decreased, storage lesions were observed, and cells underwent apoptosis. We investigated the effects of caspase-3 inhibitor on the survival and function of platelets after different periods of storage. METHODS: Platelet concentrates were obtained from the Iranian Blood Transfusion Organization in plastic blood bags. Caspase-3 inhibitor (Z-DEVD-FMK) was added to the bags. These bags along with control bags to which no inhibitor was added were stored in a shaking incubator at 22degrees C for 7 days. The effects of Z-DEVD-FMK on the functionality of platelets were analyzed by assessing their ability to bind to von Willebrand factor (vWF) and to aggregate in the presence of arachidonic acid and ristocetin. Cell survival was surveyed by MTT assay. RESULTS: At day 4 of storage, ristocetin-induced platelet aggregation was significantly higher in the inhibitor-treated (test) than in control samples; the difference was not significant at day 7. There was no significant difference in arachidonic acid-induced platelet aggregation between test and control samples. However, at day 7 of storage, the binding of platelets to vWF was significantly higher in test than in control samples. The MTT assay revealed significantly higher viability in test than in control samples at both days of study. CONCLUSION: Treatment of platelets with caspase-3 inhibitor could increase their functionality and survival.
Apoptosis ; Arachidonic Acid ; Blood Platelets* ; Blood Transfusion ; Caspase 3* ; Cell Survival ; Incubators ; Plastics ; Platelet Aggregation ; Ristocetin ; von Willebrand Factor

BACKGROUND: The limit and the optimal method of the cryopreservation of platelets have not been determined. Moreover, the functional changes platelets after cryopreservation were not clearly defined. This study was conducted to determine the limit and optimal method for cryopreservation of platelet concentrates. METHODS: We compared the recovery, expression of membrane GpIb, GpIIb/IIIa, and aggregatory function of the platelets preserved in three different conditions. Platelet samples were collected from four healthy volunteer donors by apheresis, and placed in 22degrees C agitator for standard preservation. For cryopreservation, after treating 5% DMSO, platelets were either inserted directly in -80degrees C freezer or in liquid nitrogen after computer-controlled rate freezing. After storage for 5 days, 1 week, 2 weeks, 3 weeks, 4 weeks, and 12 weeks, platelets were thawed and analyzed for the evaluation of in vitro functions. RESULTS: Platelets preserved at 22degrees C or cryopreserved with each condition displayed equivalent recovery (90%). With each cryopreservation procedures, platelets showed moderate loss of GpIb and retained more than 90% of GpIIb/IIIa in comparison with fresh platelets. At the third week, loss of GpIb in the directly frozen platelets was augmented compared with those of controlled rate frozen group. The aggregatory response to ristocetin began to decrease drastically after storage for 5 days in platelets frozen by each procedures and to less than 5% at 12 weeks of storage. However, controlled rate frozen platelets retained more aggregatory response to ristocetin and surface GpIb expression than those of directly frozen platelets at 3, 4, 12 weeks of storage. CONCLUSION: This study showed the possibility of moderate preservation of in vitro functions of frozen-thawed platelets after 12 weeks of storage compared with those of the liquid stored 5-day old platelets.
Blood Component Removal ; Blood Platelets ; Cryopreservation* ; Dihydroergotamine ; Dimethyl Sulfoxide ; Freezing ; Healthy Volunteers ; Humans ; Membrane Glycoproteins ; Membranes ; Nitrogen ; Ristocetin ; Tissue Donors

Epstein's syndrome is a rare disease whish is characterized by the association of thrombocytopenia, macrothrombocytopathia, nephritis and deafness. We experienced a case of Epstein's syndrome in a 12 years old male patient who was presented with a life long history of bleeding, usually as epistaxis, bilateral sensorineural deafness and hematuria with proteinuria starting in late childhood. Hematologic studies showed thrombocytopenia with giant platelets and anemia. A bone marrow aspirate revealed the megakaryocytes to be adequate in number and many giant size platelets. Platelet do not respond to addition of A and epinephrine; collagen and ristocetin induced agglutination response is decreased. It is difficult to be certain the association of thrombocytopenia with giant platelets, nephritis and deafness constitutes a new hereditary disease with a distinct pathogenesis or if it is an expansion of the well recognized Alport's syndrome of hereditary nephritis deafness. We report a case of Epstein's syndrome syndrome with brief review of related literatures.
Agglutination ; Anemia ; Blood Platelets ; Bone Marrow ; Child ; Collagen ; Deafness ; Epinephrine ; Epistaxis ; Genetic Diseases, Inborn ; Hematuria ; Hemorrhage ; Humans ; Male ; Megakaryocytes ; Nephritis ; Nephritis, Hereditary ; Proteinuria ; Rare Diseases ; Ristocetin ; Thrombocytopenia

We tried to analyze the status of 10 units of frozen thawed apheresis platelet concentration by 6% DMSO method for the evaluation of practical applicability. The platelet concentrations were transferred to PL-732(Baxter, USA) cryopreservation bag, and DMSO is added to those bag at slow rate until expected final 6% concentration is achieved, thereafter those were directly placed to -80 degrees C refrigerator for freezing. Someday later from I week to 1 month, those were thawed at 37 degrees C water bath, and then washed by same volume of ABO matched plasma. In the course of cryopreservation, about 7% of platelets were lost and the mean recovery rate of platelet was 93% compared with those of unfrozen status. LDH, the values of platelet lysis, and pH were within normal limits, whereas platelet aggregation test shows decreased aggregation to collagen and ristocetine compared with those of unfrozen status(p<0.05) but they were clinically acceptable. We suggest that the frozen platelets may be useful in a some clinical situation such as hematologic malignancy and solid tumor by autologous transfusion.
Baths ; Blood Component Removal ; Blood Platelets* ; Collagen ; Cryopreservation* ; Dimethyl Sulfoxide* ; Freezing ; Hematologic Neoplasms ; Hydrogen-Ion Concentration ; Plasma ; Platelet Aggregation ; Ristocetin ; Water

BACKGROUND: Essential thrombocythemia (ET) is a rare chronic myeloproliferative disorder characterized by an extremely high platelet count in the circulating blood and abnormal proliferation of the megakaryocytes in bone marrow, resulting in splenomegaly, thromboembolic or hemorrhagic complications. We studied the presence of nuclear hyperploidy of the megakaryocytes in bone marrow, the presence of abnormal response to the individual reagent on platelet aggregation test, and its clinical implication. METHODS: We analyzed the 43 cases of ET at the Asan Medical Center between January, 1989 and March, 1999. The Polycythemia Vera Study Group criteria were used to diagnose ET. RESULTS: Nuclear hyperploidy was observed at 43 cases (100%). Platelet aggregation test was done at 32 (74.4%) cases, of which 27 (84.4%) cases showed abnormal response to more than one reagent, 16 (50%) cases to more than two reagents. Abnormal response to epinephrine and collagen was most common, but 5 cases showed normal response. By individual reagent, 1 (3%) cases to adenosine diphosphate, 1 (3%) case to ristocetin, 22 (69%) cases to epinephrine, 19 (59%) cases to collagen showed abnormal response. CONCLUSION: We observe that nuclear hyperploidy of the megakaryocyts and abnormal response on platelet aggregation test are frequent in ET in this study.
Adenosine Diphosphate ; Blood Platelets* ; Bone Marrow ; Chungcheongnam-do ; Collagen ; Epinephrine ; Indicators and Reagents ; Megakaryocytes* ; Myeloproliferative Disorders ; Platelet Aggregation* ; Platelet Count ; Polycythemia Vera ; Ristocetin ; Splenomegaly ; Thrombocythemia, Essential*