Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HEMOSTATICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources

Hemorheological and hemostatic parameters in children with nephrotic syndrome undergoing steroid therapy.

Disturbances in hemostatic and hemorheological parameters have been investigated in a group of 29 children with nephrotic syndrome: 23 children classified as steroid-sensitive and 6 as steroid-resistant. Studies were performed before prednisone treatment and 3 weeks later, after initiation of steroid therapy. Before treatment, the alterations in hemostatic system involved moderate thrombocytosis with spontaneous aggregation in 19 patients. High levels of fibrinogen, factor VIII, Willebrand factor, protein C, protein S and alpha 2-macroglobulin (alpha 2M) were observed. Factor XII and alpha 1-antitrypsin (alpha 1AT) were lower than normal. Antithrombin III (ATIII) level was normal in the majority of patients. A plasma and blood hyperviscosity syndrome was also observed as well as an increase in erythrocyte aggregation. During treatment, an improvement in the hemostatic parameters was observed in the patients who responded to prednisone. The expected increase in factor VIII (frequently described in the literature) was not observed, while there was a significant increase in protein C. In the steroid-resistant patients, the only significant changes observed were decreased fibrinogen and increased protein C. The hemorheological parameters showed a tendency towards normality regardless of whether or not the treatment provided remission of NS. The relationship between hemorheological and hemostatic factors changes are discussed.

Adolescent↗

Soluble fibrin monomer complexes and other hemostatic parameters in patients with intrauterine fetal death.

Hemostatic parameters, especially soluble fibrin monomer complexes, have been studied in 114 patients with intrauterine fetal death. The patients were classified into three groups according to the duration of fetal retention. A correlation was observed between a longer duration of fetal retention and the hemostatic alteration. Moreover, in the groups of patients in which this hemostatic disorder was more evident, an improvement in these alterations was detected after fetal evacuation. A hemorrhagic picture with consumption of coagulation factors and cross-linked fibrin oligomers was detected after uterine evacuation in only 1 case and required an emergency hysterectomy and the administration of blood and plasma. In the rest of the patients, fetal evacuation was sufficient to normalize the parameters and no hemorrhagic complications were observed. The favorable evolution and minimal hemostatic alterations in the majority of the patients with intrauterine fetal death, when early obstetric management was established, are discussed.

Adult↗

Lifestyle and hemostatic risk factors for ischemic heart disease : the Caerphilly Study.

We have recently shown that fibrin D-dimer, tissue plasminogen activator (tPA) antigen, von Willebrand factor antigen, fibrinogen, plasma viscosity, and white cell count are associated with subsequent ischemic heart disease (IHD) in men aged 49 to 65 years in the Caerphilly Study from South Wales. We now report the contribution of major lifestyle factors to plasma levels of these new risk predictors for IHD. Results were available for up to 2188 men. The contribution of factors associated with lifestyle (smoking, alcohol, body mass index, leisure and work activity, social class, and use of prescribed medicines) to variation in plasma levels of 8 hemostatic variables was examined. All results were adjusted for other lifestyle variables, age, and time of day. Most hemostatic variables increased with age and smoking habit. Increasing levels of alcohol consumption were associated with increases in tPA and plasminogen activator inhibitor (PAI-1) activity and with decreases in fibrinogen and white cell count. tPA, PAI-1, fibrinogen (nephelometric), and viscosity were positively associated with body mass index. Increasing levels of leisure activity were inversely associated with D-dimer, von Willebrand factor, nephelometric fibrinogen, and viscosity. Use of prescribed medicines (a marker for chronic illness) was associated with adverse levels of D-dimer, fibrinogen, plasma viscosity, and white cell count. tPA, PAI-1, and plasma viscosity were associated with blood pressure, cholesterol, and triglycerides but not with lipoprotein(a) or homocysteine. We conclude that several lifestyle factors are associated with hemostatic risk predictors for IHD. Lifestyle modifications may reduce IHD risk partly by altering hemostatic function; large intervention studies are required to test this hypothesis.

Aged↗

Hypobetalipoproteinemia is associated with low levels of hemostatic risk factors in the Framingham offspring population.

BACKGROUND: Given the importance of thrombosis in causation of acute coronary syndromes, it is possible that the beneficial effect of low lipid levels on the risk of coronary events is achieved by lowering thrombotic potential of the blood. Hypobetalipoproteinemia is characterized by plasma concentrations of apolipoprotein B and LDL cholesterol that are one third of those observed in the general population. The aim of this study was to utilize subjects with hypobetalipoproteinemia to examine the relation between thrombotic potential and low levels of LDL cholesterol. METHODS AND RESULTS: Hemostatic risk factors were measured in 1878 individuals (1003 women and 875 men) participating in cycle 5 of the Framingham Offspring Study. The subjects were divided into five groups on the basis of LDL cholesterol level. Subjects with hypobetalipoproteinemia (LDL cholesterol < 70 mg/dL) had the lowest levels of fibrinogen, plasminogen activator inhibitor-1 antigen, and tissue plasminogen activator antigen. As LDL cholesterol increased, there was a significant increase in the levels of the hemostatic risk factors, with the exception of von Willebrand factor antigen. Adjustment with multivariate regression analyses for the covariates age, sex, body mass index, diabetes mellitus, smoking, alcohol intake, triglyceride level, and use of antihypertensive medication did not materially alter the results. CONCLUSIONS: Decreasing levels of LDL cholesterol are associated with decreasing levels of hemostatic risk factors. Subjects with hypobetalipoproteinemia have the lowest levels of hemostatic risk factors and may be protected against thrombotic complications of atherosclerotic cardiovascular disease because of reduced thrombotic potential. One mechanism by which lipid-lowering therapy may decrease clinical cardiac events is through a reduction in thrombotic tendency.

Apolipoproteins B↗

Prospective study of hemostatic factors and incidence of coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) Study.

BACKGROUND: Although hemostatic factors contribute to acute coronary syndromes and atherogenesis, few studies have prospectively evaluated the association between multiple hemostatic factors and coronary heart disease incidence. METHODS AND RESULTS: The Atherosclerosis Risk in Communities Study recruited 14,477 adults from 45 to 64 years of age who were initially free of coronary heart disease. Coronary disease risk factors and several plasma hemostatic factors were measured, and incidence of coronary heart disease was ascertained during an average follow-up of 5.2 years. Age-, race-, and field center-adjusted relative risks of coronary heart disease were significantly elevated (P < or = .05) per higher value of fibrinogen (relative risk: men, 1.76; women, 1.54), white blood cell count (men, 1.68; women, 2.23), factor VIII coagulant activity (women, 1.25), and von Willebrand factor antigen (men, 1.20; women, 1.18). Adjustment for other risk factors attenuated these associations for fibrinogen (adjusted relative risk: men, 1.48; women, 1.21), and it eliminated the white blood cell count, factor VIII, and von Willebrand factor associations, consistent with the other risk factors either confounding or partly operating through their effects on the hemostatic variables. Adjusted standardized relative risks of total mortality, ranging from 1.13 to 1.37, were also elevated (P < .05) in relation to these four factors. There was no association of coronary disease incidence with factor VII, protein C, antithrombin III, or platelet count. CONCLUSIONS: Elevated levels of fibrinogen, white blood cell count, factor VIII, and von Willebrand factor are risk factors and may play causative roles in coronary heart disease. However, their measurement in healthy adults appears to add little to prediction of coronary events beyond that of more established risk factors.

Aged↗

Which hemostatic markers add to the predictive value of conventional risk factors for coronary heart disease and ischemic stroke? The Caerphilly Study.

BACKGROUND: Few studies have examined whether hemostatic markers contribute to risk of coronary disease and ischemic stroke independently of conventional risk factors. This study examines 11 hemostatic markers that reflect different aspects of the coagulation process to determine which have prognostic value after accounting for conventional risk factors. METHODS AND RESULTS: A total of 2398 men aged 49 to 65 years were examined in 1984 to 1988, and the majority gave a fasting blood sample for assay of lipids and hemostatic markers. Men were followed up for a median of 13 years, and cardiovascular disease (CVD) events were recorded. There were 486 CVD events in total, 353 with prospective coronary disease and 133 with prospective ischemic stroke. On univariable analysis, fibrinogen, low activated protein C ratio, D-dimer, tissue plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) were associated significantly with risk of CVD. On multivariable analyses with conventional risk factors forced into the proportional hazards model, fibrinogen, D-dimer, and PAI-1 were significantly associated with risk of CVD, whereas factor VIIc showed an inverse association (P=0.001). In a model that contained the conventional risk factors, the hazard ratio for subsequent CVD in the top third of the distribution of predicted risk relative to the bottom third was 2.7 for subjects without preexisting CVD. This ratio increased to 3.7 for the model that also contained the 4 hemostatic factors. CONCLUSIONS: Fibrinogen, D-dimer, PAI-1 activity, and factor VIIc each has potential to increase the prediction of coronary disease/ischemic stroke in middle-aged men, in addition to conventional risk factors.

Aged↗

Hemostatic indices in healthy foals from birth to one month of age.

Hemostatic indices were determined in 45 healthy light breed foals, from birth to 1 month of age, and in 20 healthy adult (> 2 years of age) light breed horses. Blood samples were obtained from each foal at 4 ages: 1) < 24 hours, 2) 4-7 days, 3) 10-14 days, and 4) 25-30 days. The following hemostatic indices were determined: platelet count; prothrombin and activated partial thromboplastin times; activity concentrations of protein C, antithrombin III, plasminogen, alpha-2 antiplasmin, tissue plasminogen activator, and plasminogen activator inhibitor-1; plasma protein C antigen and fibrinogen concentrations; and serum fibrin degradation products concentration. Prothrombin and activated partial thromboplastin times were significantly longer at birth than in older foals. The plasma concentrations of the following were significantly lower at birth than in older foals: antithrombin III, plasminogen and tissue plasminogen activator activities, protein C antigen, and fibrinogen. Concentrations of the following were significantly higher at birth than in older foals: protein C and plasminogen activator inhibitor-1 activities and fibrin degradation products. These results indicate that hemostatic indices of neonatal foals differ significantly from those of older foals and adults. With the exceptions of antithrombin III and tissue plasminogen activator activities, all hemostatic indices measured in foals at 1 month of age were equivalent to adult values.

Aging↗

Insulin resistance, hemostatic factors, and hormone interactions in pre- and perimenopausal women: SWAN.

We evaluated the association of hemostatic factors with insulin resistance in relation to reproductive hormones including FSH, estradiol, testosterone, and SHBG. SHBG was used to calculate the free estradiol index and free androgen index. We studied 3,200 women, aged 42-52 yr, in the Study of Women's Health Across the Nation, a prospective multiethnic study of the menopausal transition. We measured the hemostatic factors, fibrinogen, factor VIIc, tissue plasminogen activator (t-PA), and plasminogen activator inhibitor type 1 (PAI-1), as well as glucose and insulin to calculate insulin resistance. After adjustment for body mass index, site, and ethnicity, SHBG was correlated with PAI-1 (partial r = -0.30) and t-PA (partial r = -0.12). Although testosterone was associated with t-PA (partial r = 0.13) and PAI-1 (partial r = 0.07), free androgen index was strongly correlated with t-PA (partial r = 0.18) and PAI-1 (partial r = 0.26). SHBG modified the association of hemostatic factors with insulin resistance. Women with greater insulin resistance had lower SHBG and higher PAI-1. Estrogen measures were not associated with insulin resistance. The influence of sex hormones on hemostatic factors and insulin resistance is poorly understood. SHBG, which influences the amount of bioavailable hormone, significantly modified the association of PAI-1 and t-PA with insulin resistance. The longitudinal Study of Women's Health Across the Nation will help us discern whether this interaction contributes to heart disease and diabetes among postmenopausal women.

Adult↗

Effects of anticoagulation intensity on hemostatic markers in patients with non-valvular atrial fibrillation.

BACKGROUND: Elevation of hemostatic markers may account for the increased risk of ischemic stroke in patients with non-valvular atrial fibrillation (NVAF). The aim of this study was to determine the effects of anticoagulation intensity on hemostatic markers in patients with NVAF. METHODS AND RESULTS: In 509 patients with NVAF, comprising 263 patients treated with warfarin and 246 patients without warfarin, the hemostatic markers of prothrombin fragment F1.2 (F1.2), fibrin D-dimer, platelet factor 4 (PF4), and beta-thromboglobulin were determined and compared with those in 111 patients with sinus rhythm. F1.2 was inversely related with anticoagulation intensity and D-dimer increased with age. All hemostatic markers, except F1.2, were greater in patients with NVAF than in patients with sinus rhythm. F1.2 and D-dimer were significantly lower in patients with international normalized ratio (INR) > or =1.5 than in NVAF patients without warfarin and were not different between NVAF patients with INR of 1.5-1.9 and with INR > or =2.0. CONCLUSIONS: Low intensity of anticoagulation (INR 1.5-1.9) suppresses the elevated concentration of F1.2 and D-dimer in patients with NVAF, and might be favorable in Japanese patients with NVAF in view of the balance between prevention of thromboembolism and the adverse effect by warfarin (ie, bleeding).

Adult↗

Progression of retinopathy after improved metabolic control in type 2 diabetic patients. Relation to IGF-1 and hemostatic variables.

OBJECTIVE: To determine the impact of improved glycemic control on the development and progression of retinopathy after the institution of insulin therapy in patients with type 2 diabetes and to assess the relation to IGF-1 and hemostatic variables. RESEARCH DESIGN AND METHODS: In a prospective observational study, 45 type 2 diabetic patients were examined at baseline and 1, 3, 6, 12, and 24 months after change to insulin therapy. Retinopathy was graded on fundus photographs using the Wisconsin scale; HbA1c, IGF-1, and hemostatic variables were measured. RESULTS: During the observation period of 2 years, 23 patients progressed in the retinopathy scale; 8 progressed > or = 3 levels. After 2 years of insulin treatment, HbA1c and IGF-1 were significantly lower than at baseline, whereas the hemostatic variables had not changed significantly. Progression of retinopathy > or = 3 levels was related to the degree of HbA1c reduction, the duration of diabetes, a higher prothrombin fragment 1 + 2 levels (F1 + 2), but not to other hemostatic variables or IGF-1. The relative risk for progression > or = 3 levels was 2.6 when HbA1c had been reduced > or = 3 percent units (95% CI 1.1-6.1). CONCLUSIONS: The magnitude of improvement of HbA1c by the institution of insulin treatment over a 2-year period may be associated with progression of retinopathy in patients with type 2 diabetes.

Diabetes Mellitus, Type 2↗

Assessment of a point-of-care instrument for identification of primary hemostatic disorders in dogs.

OBJECTIVE: To assess a point-of-care instrument for identification of primary hemostatic disorders in dogs. ANIMALS: 29 healthy dogs and 23 nonanemic dogs with primary hemostatic disorders (thrombocytopenia, n = 6; thrombopathia, 6; von Willebrand disease [vWD], 11). PROCEDURE: Citrated blood was obtained and closure times (CT) were determined by measuring the time required for occlusion of an aperture by a platelet plug within the point-of-care instrument. Reference ranges for CT were established, and CT were determined for dogs with primary hemostatic disorders. RESULTS: CT measured with adenosine diphosphate as the platelet agonist (ADP-CT) ranged from 52 to 86 seconds for healthy dogs (mean +/- 2 SD, 67 +/- 7.8 seconds; median, 65 seconds), and CT measured with epinephrine as the agonist (EPI-CT), from 97 to 225 seconds (151 +/- 38 seconds; 148 seconds). In thrombocytopenic dogs, ADP- and EPI-CT were prolonged (> 165 and > 264 seconds, respectively). Five of 6 dogs with thrombopathia had prolonged ADP-CT, whereas EPI-CT was prolonged in all 6 dogs. In all dogs with vWD, ADP-CT was prolonged; EPI-CT was prolonged in 10 of these dogs. Sensitivity and specificity for ADP-CT were 95.7 and 100%, respectively, and positive and negative predictive values, 100 and 96.7%, respectively, whereas for EPI-CT, these values were 95.7 and 82.8%, respectively, and 81.5 and 96%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The point-of-care instrument allowed quick assessment of primary hemostasis in nonanemic dogs. Use of this instrument may be helpful for making decisions regarding management of dogs with primary hemostatic disorders.

Adenosine Diphosphate↗

Neutrophil activation and hemostatic changes in healthy donors receiving granulocyte colony-stimulating factor.

Granulocyte colony-stimulating factor (G-CSF) enhances neutrophil functions in vitro and in vivo. It is known that neutrophil-derived products can alter the hemostatic balance. To understand whether polymorphonuclear leukocyte (PMN) activation, measured as PMN degranulation and phenotypical change, may be associated to hemostatic alterations in vivo, we have studied the effect of recombinant human G-CSF (rHuG-CSF) administration on leukocyte parameters and hemostatic variables in healthy donors of hematopoietic progenitor cells (HPCs). Twenty-six consecutive healthy donors receiving 10 micrograms/kg/d rHuG-CSF subcutaneously for 5 to 7 days to mobilize HPCs for allogeneic transplants were included in the study. All of them responded to rHuG-CSF with a significant white blood cell count increase. Blood samples were drawn before therapy on days 2 and 5 and 1 week after stopping rHuG-CSF treatment. The following parameters were evaluated: (1) PMN activation parameters, ie, surface CD11b/CD18 antigen expression, plasma elastase antigen levels and cellular elastase activity; (2) plasma markers of endothelium activation, ie, thrombomodulin (TM) and von Willebrand factor (vWF) antigens; (3) plasma markers of blood coagulation activation, ie, F1+2, TAT complex, D-dimer; and (4) mononuclear cell (MNC) procoagulant activity (PCA) expression. The results show that, after starting rHuG-CSF, an in vivo PMN activation occurred, as demonstrated by the significant increment of surface CD11b/CD18 and plasma elastase antigen levels. Moreover, PMN cellular elastase activity, which was significantly increased at 1 day of treatment, returned to baseline at day 5 to 6, in correspondence with the elastase antigen peak in the circulation. This change was accompanied by a parallel significant increase in plasma levels of the two endothelial and the three coagulation markers. The PCA generated in vitro by unstimulated MNC isolated from rHuG-CSF-treated subjects was not different from that of control cells from untreated subjects. However, endotoxin-stimulated MNC isolated from on-treatment individuals produced significantly more PCA compared with both baseline and control samples. All of the parameters were decreased or normal 1 week after stopping treatment. These data show that rHuG-CSF induces PMN activation and transiently affects some hemostatic variables in healthy HPC donor subjects. The clinical significance of these findings remains to be established.

Adolescent↗

[Application of hemostatic molecular markers for diagnosis of thrombosis].

We examined various hemostatic molecular markers in patients with disseminated intravascular coagulation(DIC), deep vein thrombosis(DVT), pulmonary embolism(PE), acute myocardial infarction(AMI), cerebral thrombosis(CT) and thrombotic thrombocytopenic purpura(TTP). Global tests were sensitive for DIC but not for pre-DIC. However, hemostatic molecular markers such as soluble fibrin were sensitive for both DIC and pre-DIC. Hemostatic molecular markers were also useful for analysis of DIC in a baboon DIC model. Activated protein C-protein C inhibitor complex and plasminogen activator inhibitor-I were useful for the diagnosis of DVT, PE, AMI or CT. These findings suggests that hemostatic molecular markers are useful for the diagnosis of various thrombotic disorders.

Animals↗

Hemostatic complications associated with paraproteinemias.

Hemorrhagic events are a common complication at diagnosis, during treatment, and with disease progression of lymphoproliferative disorders that produce monoclonal immunoglobulins or paraproteins. Typical causes of bleeding include vascular infiltration by malignant cells, hyperviscosity syndrome, thrombocytopenia secondary to bone marrow infiltration or treatment, uremia, and coagulopathies secondary to liver dysfunction or sepsis. However, there are several unique hemostatic derangements associated with lymphoproliferative disorders that express paraproteins and these are the subject of this article (eg, inhibition of fibrin polymerization, qualitative platelet dysfunction, acquired von Willebrand factor deficiency, heparin-like circulating anticoagulants, light chain amyloid associated hemostatic disorders, acquired coagulation factor deficiencies, and acquired hypercoagulable states). The exact role that paraproteins play in many of these conditions is unknown or incompletely investigated. Often, abnormal hemostasis test results are not accompanied by clinically apparent hemostatic complications. Management of paraprotein-related hemostatic complications varies in strategy and efficacy, depending on the underlying mechanism and type of lymphoproliferative disease.

Blood Coagulation Disorders↗

Preoperative and postoperative hemostatic profiles of dogs undergoing ovariohysterectomy.

Hemostatic profiles were evaluated in 15 healthy dogs immediately before and 24 hours after celiotomy for routine ovariohysterectomy. Prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin degradation products, antithrombin III activity, platelet count, and hemogram were measured. There were no significant changes in prothrombin time, activated partial thromboplastin time, fibrin degradation products, antithrombin III activity, or platelet count. Fibrinogen concentration was significantly higher following surgery. Postoperative leukocyte differential counts were typical of stress leukograms, and were characterized by leukocytosis, neutrophilia, lymphopenia and eosinopenia. Mild decreases in packed cell volume, red blood cell count and hemoglobin concentration were consistent with minor blood loss during surgery or fluid retention and hemodilution postoperatively. It was concluded that celiotomy and routine ovariohysterectomy in healthy dogs did not alter hemostatic profiles 24 hours after surgery. Abnormal postoperative hemostatic profiles should not be attributed to surgery alone; other causes of abnormal hemostatic profiles should be investigated.

Animals↗

Evaluation of hemostatic analytes after use of hypertonic saline solution combined with colloids for resuscitation of dogs with hypovolemia.

The effects of hypertonic saline solution (HTSS) combined with colloids on hemostatic analytes were studied in 15 dogs. The analytes evaluated included platelet counts, one-stage prothrombin time, activated partial thromboplastin time, von Willebrand's factor antigen (vWf:Ag), and buccal mucosa bleeding times. The dogs were anesthetized, and jugular phlebotomy was used to induced hypovolemia (mean arterial blood pressure = 50 mm of Hg). Treatment dogs (n = 12) were resuscitated by infusion (6 ml/kg of body weight) of 1 of 3 solutions: HTSS combined with 6% dextran 70, 6% hetastarch, or 10% pentastarch. The control dogs (n = 3) were autotransfused. Hemostatic analytes were evaluated prior to induction of hypovolemia (baseline) and then after resuscitation (after 30 minutes of sustained hypovolemia) at 0.25, 0.5, 1, 6 and 24 hours. All treatment dogs responded rapidly and dramatically to resuscitation with hypertonic solutions. Clinically apparent hemostatic defects (epistaxis, petechiae, hematoma) were not observed in any dog. All coagulation variables evaluated, with the exception of vWf:Ag, remained within reference ranges over the 24-hour period. The vWf:Ag values were not statistically different than values from control dogs, and actual values were only slightly lower than reference ranges. Significant (P < or = 0.04) differences were detected for one-stage prothrombin time, but did not exceed reference ranges. The results of this study suggested that small volume HTSS/colloid solutions do not cause significant alterations in hemostatic analytes and should be considered for initial treatment of hypovolemic or hemorrhagic shock.

Animals↗

Evaluation of hemostatic defects secondary to vascular tumors in dogs: 11 cases (1983-1988).

Two populations of dogs with cutaneous hemangiomas and hemangiosarcomas were evaluated retrospectively. One population consisted of 96 dogs seen at the Veterinary Medical Teaching Hospital at the University of California, Davis. The second population consisted of 116 dogs that had skin biopsy specimens submitted to a private veterinary diagnostic laboratory for histologic diagnosis. Nine dogs from the teaching hospital and 2 dogs, from which samples had been submitted to the veterinary diagnostic laboratory, developed hemostatic defects in association with the tumors. Hemostatic defects included hemorrhage directly from the tumor, thrombocytopenia, hypofibrinogenemia, and findings associated with disseminated intravascular coagulation. Because bleeding during surgery can develop in animals with hemostatic defects, dogs with one or more tumors suspected of being vascular in origin should have platelet numbers and hemostatic analytes evaluated prior to surgery, especially if petechiae or ecchymoses are evident.

Anemia↗

Tumor necrosis factor infusions have a procoagulant effect on the hemostatic mechanism of humans.

Several investigators have reported that tumor necrosis factor (TNF) can alter the hemostatic properties of vascular endothelial cells in vitro. We have examined the in vivo effects on the hemostatic mechanism of recombinant human TNF administered as a continuous intravenous infusion to 23 cancer patients with active disease. A battery of sensitive and specific immunochemical techniques were used to monitor changes in blood coagulability. Serial determinations of F1 + 2, the protein C activation peptide (PCP), and fibrinopeptide A (FPA) were obtained prior to the initiation of the TNF infusions and at three and 24 hours after the start of therapy in 12 individuals who received greater than 3 x 10(5) U/m2/24h. The mean levels of F1 + 2, PCP, and FPA were significantly elevated at both time points as compared to the baseline values. The metabolic behavior of 125I-F1 + 2 in an animal model was not affected by infusions of the cytokine. We therefore conclude that the observed elevations in the concentration of this marker in humans receiving TNF result from hemostatic system hyperactivity. In 11 subjects infused with 1 x 10(5) to 2.4 x 10(5) U/m2/24 h of the cytokine, the mean levels of F1 + 2, PCP, and FPA were not significantly greater at 24 hours as compared with the baseline values, indicating that there is a threshold dose at which the cytokine can exert a biochemical effect on the coagulation system. Our studies demonstrate that TNF is able to provide a substantial net procoagulant stimulus to the hemostatic mechanism, and suggest that this cytokine may be a mediator of certain hypercoagulable states in humans.

Blood Coagulation Tests↗