Platelet factor 4 (PF4) and heparin released platelet factor 4 (HR-PF4) in diabetes mellitus. Effect of the duration of the disease

Several investigators have reported an altered platelet function in diabetes mellitus as measured by elevated levels of platelet specific proteins platelet factor 4 (PF4) and B-thromboglobulin (BTG). We studied 20 insulin dependent (IDD), 20 non insulin dependent (NIDD) diabetic males without overt clinical symptoms of cardiovascular disorders and 30 normal controls. We evaluated PF4, BTG and heparin released platelet factor 4 (HR-PF4) as measured 2.5 minutes after a bolus injection of 5,000 I.U. of a commercial mucous heparin. The patients showed normal levels of both PF4 and BTG. Furthermore HR-PF4 failed to show statistically significant variation between patients and controls. However when the diabetics were divided on the basis of the duration of the disease, the IDD had an increased HR-PF4 mean level and the trend became statistically significant when diabetes existed more than 17 years (patients HR-PF4 149.1 ng/ml, range 17.3-194; controls HR-PF4 110.9 ng/ml range 50-160, less than p less than 0.05). NIDD failed to reveal the same pattern. Although the significance of HR-PF4 is unknown, insulin dependent diabetes mellitus after many years could cause a potentially dangerous, silent vascular damage with enhanced platelet vessel wall interaction as measured by an elevated HR-PF4.     

The role of Willebrand factor in platelet - blood vessel interaction, including a discussion of resistance to atherosclerosis in pigs with von Willebrand's disease

Von Willebrand pigs have all the manifestations of the severe human disease. The role of Willebrand antigen (VIII R:AG) and ristocetin cofactor (VIII: RWF) was assessed in these pigs by (1) transfusion and (2) "in vitro" bleeding time assay. The skin bleeding time became normal when the level of transfused Willebrand factor (VIII R:AG/RWF) was raised in the plasma above 30 U/dl. After single or repeated transfusions, skin capillary endothelium and platelets were still distinguished from normal by VIII R:AG deficiency. When incisions in excised porcine skin ("in vitro" bleeding time) were perfused with blood and plasma fractions, haemostasis occurred when plasmatic Willebrand factor exceeded 30 U/dl whether the skin or platelets came from normal or from von Willebrand pigs. The platelet plug occluding the skin incision contained VIII R:AG by immunofluorescence. Willebrand factor appears to coat surfaces and to serve as a platelet attachment protein. These bleeder pigs are resistant to atherosclerosis. If platelets are involved in early atherosclerotic lesions, the role of Willebrand factor in platelet - blood vessel interaction may be important.     

Gray platelet syndrome: selective alpha-granule deficiency and thrombocytopenia due to increased platelet turnover

Clinical and laboratory studies of two siblings, both suffering from gray platelet syndrome (GPS) are described. The patients had a mild bleeding disorder, their platelets were blue-gray in panoptic stains, and alpha-granules were markedly reduced, as shown by electron microscopy. The platelet content of platelet factor 4 and that of beta-thromboglobulin were significantly reduced (3%-7% of normal). Platelet count was decreased (33-150 X 10(9)/1) and small platelets were increased in platelet volume distribution. Bleeding time was prolonged on most occasions. Bone marrow aspiration was performed in one patient and revealed increased reticulin fibers, however, megakaryocyte count was normal. The mean platelet survival was 4.8 days using 111indium-labelled platelets. In this patient, platelet-associated IgG was within the normal range. Prednisone therapy failed to increase platelet count. Dental surgery was performed under cover of desmopressin and no bleeding complication occurred; however, no improvement of bleeding time was observed. The patient delivered a healthy male infant without hemorrhaging while under concurrent platelet transfusion therapy.     

High-dose intravenous therapy with immune globulin before delivery for idiopathic thrombocytopenic purpura.

A 15-year-old girl with a 9-year history of idiopathic thrombocytopenic purpura resistant to high-dose steroid therapy and to splenectomy was admitted to hospital at 35 weeks'' gestation with a platelet count of 10 X 10(9)/L. The bleeding time was normal, and measures of platelet aggregation were nearly so. Treatment with high intravenous doses of polyvalent immune globulin led to a rise in the platelet count to more than 110 X 10(9)/L within 5 days. An elective cesarean section was performed through the lower uterine segment with good hemostasis. After delivery the platelet count fell to its former level, but no postpartum bleeding occurred. There was a brief episode of thrombocytopenia in the infant, with some petechiae but no other hemorrhagic manifestations. No untoward effects of the immune globulin infusion were observed in either mother or daughter.     

Aspirin-Induced Prolongation of the Ivy Bleeding Time—Its Diagnostic Usefulness

Ivy bleeding time values before and two hours after ingestion of 600 mg of aspirin (aspirin tolerance test) were studied in normal persons, in patients with a disorder of primary hemostasis and in patients with various coagulation factor deficiencies. Aspirin produced a significant prolongation of the bleeding time in patients with von Willebrand''s disease, uremia, and primary platelet disease, and in two patients with Factor XI deficiency. Dextropropoxyphene hydrochloride caused no prolongation of the bleeding time in normal persons.     

Bleeding time in patients with hepatic cirrhosis.

OBJECTIVE--To determine the frequency of an abnormal bleeding time in patients with cirrhosis and to relate this to known factors that affect primary haemostasis and to the severity of liver disease. DESIGN--Prospective clinical and laboratory study in patients admitted for complications or investigations of liver disease. SETTING--Royal Free Hospital hepatobiliary and liver transplantation unit. SUBJECTS--100 Consecutive inpatients aged 17-74 with various forms of cirrhosis, including alcoholic, biliary, autoimmune, viral, and cryptogenic. At least 10 days had elapsed since any episodes of bleeding, resolution of sepsis, or alcohol intake. No patient was taking any drug known to affect primary haemostasis. MAIN OUTCOME MEASURES--Bleeding time as measured with the Simplate double blade template device. A bleeding time longer than 10 minutes was considered abnormal. Other measures were platelet count, prothrombin time, partial thromboplastin time, packed cell volume, and blood urea, serum bilirubin, and serum albumin concentrations, all measured on each subject at the same time by standard laboratory methods. RESULTS--A weak but significant correlation existed between the bleeding time and the platelet count (rs = 0.483; p less than 0.001). There were significantly lower platelet counts, longer prothrombin times, and higher blood urea and serum bilirubin concentrations in the 42 patients with bleeding times of 10 minutes or more compared with the 58 patients with bleeding times less than 10 minutes. Multiple linear regression analysis showed that the bilirubin concentration as well as the platelet count was independently correlated with the bleeding time. The combination of a platelet count greater than 80 x 10(9)/l and a prothrombin time less than 17 seconds (usually taken as safe limits for performing routine liver biopsy) did not predict a normal bleeding time. Ten of 39 patients fulfilling these criteria had a prolonged bleeding time. CONCLUSIONS--Prolonged bleeding time is common in patients with cirrhosis, even in those with prothrombin times and platelet counts within "safe limits" for invasive procedures. The severity of liver disease as assessed by the bilirubin concentration plays an important part in determining the bleeding time in cirrhosis. The bleeding time should be measured when assessing patients for invasive procedures who have a raised bilirubin concentration or poor hepatic function, even if the platelet count and prothrombin time are considered adequate.     

Platelet adhesiveness and aggregation in combined factor V and factor VIII deficiency and in combined factor VII and factor VIII deficiency.

Platelet aggregation and adhesiveness were studied in 3 patients with combined factor V and factor VIII deficiency and in 3 patients with combined factor VII and factor VIII deficiency. The first three patients belonged to three different kindreds whereas the second group belonged to the same kindred. Serotonin C14 uptake and release was also found to be normal in these patients. These studies indicate that platelet function is normal in combined defects of factor VIII. These findings were in agreement with the presence of a normal bleeding time and a normal factor VIII antigen level in all these patients.     

A novel approach for improving the yield of Bacillus subtilis transglutaminase in heterologous strains

The transglutaminase (BTG) from Bacillus subtilis is considered to be a new type of transglutaminase for the food industry. Given that the BTG gene only encodes a mature peptide, the expression of BTG in heterologous microbial hosts could affect their normal growth due to BTG’s typical transglutaminase activity which can catalyze cross-linking of proteins in the cells. Therefore, we developed a novel approach to suppress BTG activity and reduce the toxicity on microbial hosts, thus improving BTG yield. Genes encoding the respective regions of transglutaminase propeptide from seven species of Streptomyces were fused to the N-terminal of the BTG gene to produce fusion proteins. We found that all the fused propeptides could suppress BTG activity. Importantly, BTG activity could be completely restored after the removal of the propeptides by proteolytic cleavage. Of the seven propeptides tested, the propeptide proD from Streptomyces caniferus had the strongest suppressive effect on BTG activity (70 % of the activity suppressed). Moreover, fusion protein proD-BTG (containing proD) also exhibited the highest yield which was more than twofold of the expression level of BTG in an active form in Escherichia coli. Secretion expression of BTG and proD-BTG in Corynebacterium glutamicum further showed that our novel approach was suitable for the efficient BTG expression, thus providing a valuable platform for further optimization of large-scale BTG production.     

Abnormalities of platelet aggregation in chronic myeloproliferative disorders

A large variety of platelet dysfunctions has been described in chronic myeloproliferative disorders. These abnormalities may be due to deficiency of platelet granules, arahidonic acid metabolism defects or platelet membrane glycoproteins abnormalities. In this study we intend to detect the incidence of platelet function defects in 76 patients with various types of chronic myeloproliferative disorders. The platelet activity was studied in vitro by measuring platelet aggregation in response to ADP, epinephrine, collagen, arachidonic acid and ristocetin. These results were subsequently correlated with bleeding time and clinical aspects (bleeding or thrombosis). We found complex changes in platelet response with all agonists, in varied proportions. These abnormalities include absent, decreased or abnormal platelet aggregation response. In a few cases we found a markedly decreased, almost absent platelet response to all agonists while in some patients a normal platelet aggregation was noted. The correlation between these results and template bleeding time, thrombotic or hemorrhagic events and the type of diseases was difficult to establish and sometimes conflictual. Despite this fact, we consider that investigating platelet aggregation may be useful not only for the assesment of the hemostatic balance in chronic myeloproliferative disorders but also for a better insight into cell abnormalities occuring in these pathologic conditions.     

APRO家族基因在胃癌中的表达及预后意义

目的:基于大数据挖掘分析BTG/Tob抗增殖蛋白家族(anti-proliferativeprotein family,APRO)基因在胃癌组织的表达及其对胃癌患者预后的影响。方法:采用Oncomine数据库分析APRO家族6个成员在胃癌组织中的m RNA表达情况,通过Kaplan-Meier Plotter数据库进行胃癌患者总生存期的分析。结果:相比正常胃组织,BTG2在胃癌组织中呈低表达;BTG3在肠型胃癌组织中呈高表达,而在总体胃癌组织中呈低表达。BTG3低表达的患者总生存期较短;对5-氟尿嘧啶辅助化疗的胃癌患者,低表达BTG2的预后较差。结论:BTG2、BTG3的m RNA表达在胃癌和正常胃组织中有明显差异。BTG3低表达的胃癌患者预后较差;BTG2可能参与调节胃癌患者5-氟尿嘧啶治疗的敏感性。     

A biochemical study on the level of lipids and glycoproteins in the serum and platelets of liver cirrhotic bleeders

Bleeding complication and abnormal platelet functions are associated with liver cirrhosis. The aim of the present investigation was to assess the functional integrity of platelets in terms of lipids like cholesterol and phospholipids, glycoproteins and membrane-bound enzymes. Liver cirrhotic patients with bleeding complications were studied. Age and sex matched normal healthy volunteers were also involved in this study as a control group. Levels of cholesterol, phospholipids, glycoproteins and adenosine triphosphatases were assessed in isolated platelet membrane fraction. The level of glycoproteins and the activity of adenosine triphosphatases were found to be decreased significantly in cirrhotic patients. The cholesterol/phospholipid ratio was found to be altered significantly, indicating an alteration in the fluidity of platelet membrane. The results of this study reveal that the functional impairment of platelets in liver cirrhotic patients which is responsible for their bleeding tendency might also be due to altered lipid and enzyme levels in platelet membrane.     

Frequent promoter hypermethylation and transcriptional downregulation of BTG4 gene in gastric cancer

The BTG4 gene belongs to the BTG family of genes endowed with antiproliferative properties. In this study, we have found that BTG4 undergoes promoter CpG island hypermethylation-associated inactivation in gastric cancer and 5′-aza-2′-deoxycytidine (DAC) treatment restores BTG4 expression. We also found BTG4 levels were significantly reduced in primary gastric cancer but not in normal gastric tissues. BTG4 reexpression in gastric cancer causes growth inhibition of colony assays and nude mice. Taken together, our data support BTG4 as a candidate tumor suppressor gene that is epigenetically silenced in the majority of gastric cancers.     

Variability in response to cryoprecipitate treatment for hemostatic defects in uremia

Cryoprecipitate is frequently administered as treatment for hemostatic defects in patients with uremia. The only published data supporting this approach however, involves seven patients described by Janson and colleagues in whom bleeding times were shortened and bleeding complications reduced after cryoprecipitate infusion. We retrospectively reviewed our institution's experience with cryoprecipitate in this setting. Five patients had sufficiently complete data for evaluation of the efficacy of therapy with cryoprecipitate, including pretreatment bleeding time greater than 15 minutes, normal coagulation studies, and platelet count greater than 100,000/microliters. Two patients had normalization of their bleeding time and a favorable clinical outcome after cryoprecipitate infusion. Three patients failed to shorten their bleeding time after cryoprecipitate infusion or, in one case, multiple infusions. One of these latter patients had correction of his abnormal bleeding time after subsequent administration of deamino-8-D-arginine vasopressin (DDAVP). We conclude that the hemostatic response to cryoprecipitate therapy is variable, and that cryoprecipitate therapy does not achieve restoration of normal hemostasis in some patients with uremic bleeding.     

Enzymological and immunological studies on a clinical case of platelet cyclooxygenase abnormality

A peroxidase-linked immunoassay of the sandwich type was developed for a quantitative determination of the amount of human cyclooxygenase. Two species of monoclonal antibodies (hPES01 against the human enzyme and PES-5 against the bovine enzyme) were utilized, which recognized different epitopes on the cyclooxygenase of human platelets. The peroxidase activity of the immunoprecipitate was correlated with the amount of cyclooxygenase. The enzyme immunoassay was applied to platelets from 15 normal subjects and a clinical case of platelet cyclooxygenase abnormality with a prolonged bleeding time. Almost the same level of immunoreactive protein was found in platelets of both normal subjects and the patient. However, the solubilized enzyme from the patient's platelets did not transform arachidonic acid to prostaglandin H2 (PGH2) while thromboxane production from PGH2 was observed at a normal level.     

Coagulation and fibrinolysis in acute mountain sickness and beginning pulmonary edema

To examine whether intravascular coagulation and/or decreased fibrinolysis precedes high-altitude pulmonary edema (HAPE) we examined 25 male mountaineers (median age 40 yr) at low altitude (550 m) and after 6, 18, and 42 h at an altitude of 4,559 m, which was climbed in 24 h. In 14 subjects, 2 of whom showed radiological evidence of HAPE after 42 h, symptoms of acute mountain sickness (AMS) were mild or absent. Eleven subjects suffered from AMS, six of whom developed radiologically documented HAPE after 18 or 42 h. In the absence of AMS there were no significant changes at high altitude, with the exception of a decrease in bleeding time from 246 +/- 18 to 212 +/- 13 (SE) (P less than 0.05). In AMS, partial thromboplastine time decreased from 34.2 +/- 0.8 to 31.1 +/- 0.5 s (P less than 0.001) and factor VIII procoagulant activity and von Willebrand factor antigen were increased by 57 +/- 12 and 70 +/- 13%, respectively (P less than 0.001), whereas there were no significant changes in beta-thromboglobulin (BTG), fibrinopeptide A (FPA), and fibrin fragment B beta 15-42. In subjects with HAPE, BTG, FPA, and B beta 15-42 were normal before and in beginning HAPE. Preceding HAPE, euglobulin clot lysis time declined at high compared with low altitude from 289 +/- 48 to 201 +/- 42 min without venous occlusion (VO) and from 107 +/- 36 to 86 +/- 31 min after VO (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Combined deficiency of factor V and factor VIII. A report of another case.

A patient with combined factor V and factor VIII deficiency is presented. The bleeding manifestations were: easy bruising, post-traumatic bleeding, bleeding after tooth extractions. The main laboratory feature was a prolonged partial thromboplastin time which was corrected by the addition of adsorbed normal plasma but not by the addition of normal serum, hemophilia A plasma of another patient with combined factor V and factor VIII deficiency. The thromboplastin generation test was clearly abnormal and was corrected by the addition of adsorbed normal plasma but not by addition of normal serum. Prothrombin consumption was also defective. Prothrombin time was slightly prolonged too, Thrombin time, platelet and vascular tests were within normal limits and there was no hyperfibrinolysis. Factor VIII was 8% of normal, whereas factor V was 14% of normal. Factor VIII associated antigen was normal. All other clotting factors were within normal limits. The parents of the propositus were consanguineous (first cousins) but had normal factor V and factor VIII activity and normal factor VIII antigen. The same was true for other family members. The hereditary transmission of the condition appears autosomal recessive.     

Blood coagulation abnormalities in Fischer strain rats bearing tumors

This study reports an unusual subpopulation of rats bearing transplanted tumors approximately 50% of the total and apparently unrelated to the presence of metastases, that exhibited shortened bleeding times despite reduced platelet numbers and/or fibrinogen levels. The remaining rats exhibited the expected inverse relationships between bleeding time and platelet numbers and/or fibrinogen level. Tumors were hepatomas and squamous cell carcinomas initially induced in the Fischer strain of rats and carried by passage through tissue culture or syngenic recipient animals.     

A study of platelet function and morphology in a new family with May-Hegglin anomaly

A new family with May-Hegglin anomaly is presented. 9 patients were found to be affected, namely to present thrombocytopenia, giant platelets, and leukocytes inclusion bodies. A mild to moderate hemorrhagic diathesis was present in 8 patients (easy bruising, excessive bleeding after tooth extraction, menomethrorrhagia). One patient was asymptomatic. The bleeding tendency seemed to be relatively more pronounced in those patients who have larger platelets. Bleeding time was slightly prolonged in 4 of the affected patients. Platelet aggregation to Ristocetin and serotonin release was normal; on the contrary, platelet adhesiveness was slightly decreased in all patients. Plasma Btg was investigated in 7 patients, found to be normal in 5 and elevated in 2. Platelet Btg was found to be increased in all patients investigated. The ratio between Btg and platelet number was elevated in every instance. The circulating platelet mass (Btg platelet mass microgram/ml) was investigated in 7 patients, found normal in two and decreased in the remaining three. The disorder is transmitted as an autosomal dominant trait but there seems to be a variable phenotypic expression from one patient to the other.     

Aberrant Expression of the p53-Inducible Antiproliferative Gene BTG2 in Hepatocellular Carcinoma is Associated with Overexpression of the Cell Cycle-Related Proteins

We previously reported that the abnormal BTG2 expression was related to genesis/development of hepatocellular carcinoma (HCC). The aim of this study was to evaluate the BTG2 expression in HCC compared with p53, cyclin D1, and cyclin E. For this purpose, modified diethylnitrosamine (DEN)-induced primary HCC rat model was established. Target proteins and mRNAs were measured by western blot and RT-PCR/northern blot, respectively. In rat liver, expression of BTG2 and other proteins was determined by western blot, and BTG2 mRNA in HCC/normal tissues was detected by high-flux tissue microarray (TMA) and in situ hybridization (ISH). BTG2 mRNA/protein expression was increased in fetal liver, 7701, and LO2 cell lines but decreased in HepG2 cells. BTG2/p53 were expressed early after DEN treatment, peaked at 5?weeks and decreased gradually thereafter. Cyclin-D1/Cyclin-E expression increased significantly with the tumor progression. BTG2 mRNA was expressed in 71.19% HCC by ISH and correlated with differentiation. Expression of p53/cyclin D1/cyclin E was positive in 82.35/94.12/76.47% BTG2 mRNA-negative tissues, respectively. BTG2 protein expression was lost in 32.2% (19/59) HCC tissues, and the mRNA/protein expression correlated significantly with the increasing tumor grade (P?相似文献   

血小板功能负性调控机制

在血液循环系统中,血小板在抑制因子的作用下,处于静息状态。当机体出血或外界因素刺激时,血小板活化,产生聚集、黏附和释放反应,释放出二磷酸腺苷(ADP)、花生四烯酸(AA)、血小板活化因子和5-羟色胺等物质,招募更多的血小板黏附于出血处,从而启动凝血过程,发挥止血作用。当止血反应完成后,血小板发生解聚,恢复到静息状态。然而,在病理条件下,血小板的内在解聚能力下降,形成过度活化的血小板,产生病理性血栓,导致急性缺血性心血管疾病的发生。临床使用抗血小板药物控制血小板的活化,治疗急性缺血性心血管疾病。然而,目前临床上常用的抗血小板药物发挥抗血小板活化作用的同时,影响了血小板正常的生理性止血作用,产生出血等副作用。因此,我们需要研发新型抗血小板药物,使其既能发挥抗血小板作用,又能减少出血等副作用。本文将对血小板负性调控机制进行综述,为进一步研究抗血小板药物提供思路。