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PubMedDate not supplied

Heparin immobilization by surface amplification.

A method to increase the amount and improve the bioactivity of heparin (HEP) immobilized on a polymer surface was developed. The surface of polyurethane-urea (PU) coated glass beads was first modified with diisocyanates, followed by surface grafting of polyfunctional polymers (PFP), including: poly(vinyl alcohol), poly(ethyleneimine), and poly(allylamine). The functional groups of the surface grafted PFP (-OH, -NH, or -NH2) were modified with diisocyanates (TDI) to amplify the surface concentration of isocyanate groups, alpha, omega-diamino-terminated polyethylene oxide (PEO; molecular weight, 4,000 daltons) was then coupled to the surface grafted PFP, and the free amino groups were derivatized with TDI. Finally, HEP was coupled to the amplified surface through free -NCO groups of PU-PFP-PEO. The surfaces were quantified during each step of the procedures for -NCO groups and HEP. All grafted surfaces showed a four to eightfold increase in -NCO content and a twofold increase in immobilized HEP content compared with HEP immobilized directly onto the PU surface. The HEP bioactivity tests (including activated partial thromboplastin time, thrombin times, and factor Xa) demonstrated an increased bioactivity of HEP when immobilized through PFP-PEO compared with PFP and PU alone.

Biocompatible Materials↗
PubMedDate not supplied

Gelfoam and autologous clot embolization: effect on coagulation.

An episode of disseminated intravascular coagulation following therapeutic gelfoam embolization to control bleeding from esophageal varices in a patient with liver disease is presented. We have since followed 13 patients prospectively (six control and seven gelfoam/autologous clot) to determine the effect of this procedure on clotting. We were unable to show significant differences between the two groups as measured by the prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen and platelet count. However, fibrin (ogen) degradation products were significantly elevated (p less than .01) in the gelfoam/autologous clot group. We suspect this occurred secondary to clot lysis at the site of embolization. No subsequent bleeding diathesis attributable to this abnormality occurred in any of the patients.

Disseminated Intravascular Coagulation↗
PubMed2001

Effects of hormone replacement on hemostasis in spontaneous menopause.

OBJECTIVE: To examine the effects of continuous combined estrogen-progesterone replacement therapy on coagulation and natural anticoagulant systems in spontaneous menopause. DESIGN: A randomized, double-blind, placebo-controlled study was conducted during a 6-month period to examine the effect of hormone replacement therapy (HRT) on blood coagulation parameters. One hundred-ten healthy postmenopausal women were randomized into two groups. Those in group 1 were given conjugated estrogen (0.625 mg/d, Premarin) and medroxyprogesterone acetate (5 mg/d, Farlutal), and those in group 2 were given identical tablets of placebo for 6 months. Serum levels of modified activated protein C resistance, antithrombin III, fibrinogen, factor VIIIa, factor VIII, factor IX, activated partial thromboplastin time, prothrombin time, thrombin time, and lipoprotein (a) were measured before and 6 months after the treatment and analyzed for changes in extrinsic and intrinsic coagulation parameters. RESULTS: At the end of the 6-month period, fibrinogen, lipoprotein (a), and activated protein C resistance levels were decreased significantly in the HRT group compared with the control group. Antithrombin III levels were increased, indicating antithrombin activity. Activated partial thromboplastin time, as a measure for intrinsic coagulation cascade, was prolonged in concert with decreased intrinsic coagulation factors, factor VIII, and factor IX (p < 0.05). In the extrinsic coagulation system, prothrombin time was significantly increased, although factor VIIa level was not changed (p > 0.05). CONCLUSION: Significant changes were observed in the coagulation parameters, which may further explain the cardioprotective effect of HRT.

Activated Protein C Resistance↗
PubMed2006

Global assessment of the coagulation status in type 2 diabetes mellitus using rotation thromboelastography.

Clinical and epidemiologic observations have led to the concept of a procoagulant state in type 2 diabetes. This study aimed to determine the coagulation status in type 2 diabetic patients using rotation thromboelastography (ROTEM), which measures the interactive dynamic coagulation process. For this purpose, 51 (30 women, 21 men) type 2 diabetic patients (mean age, 56.1 years) and 40 age-matched, sex-matched and body-mass-index-matched healthy individuals were enrolled. Twenty-seven of the diabetic group had diabetic vascular complications. ROTEM using different activators for the intrinsic and extrinsic systems of coagulation cascade (intrinsic TEM-INTEM, extrinsic TEM-EXTEM, FIBTEM) was used to measure the coagulation time (CT), clot formation time (CFT), alpha angle (alpha) and maximum clot firmness (MCF). No significant difference was found in the prothrombin time, partial thromboplastin time, thrombin time, fibrinogen and platelet count between the two groups. INTEM-CT and INTEM-CFT and EXTEM-MCF were significantly higher in the diabetic group compared with controls (P = 0.012, P = 0.007 and P = 0.029, respectively). INTEM alpha in the diabetic group was significantly lower than the controls (P = 0.001). All other parameters, including INTEM-MCF, EXTEM-CT, EXTEM-CFT, EXTEM-alpha, FIBTEM-CT, FIBTEM-CFT, FIBTEM-MCF and FIBTEM-alpha, were similar between the two groups. Taking into account these data, we conclude that there is subtle activation of the extrinsic pathway with a concomitant decrement in the intrinsic pathway of the coagulation cascade in type 2 diabetes. The exact underlying mechanisms leading to these changes, and their consequences with regard to diabetic complications, remain to be determined.

Blood Coagulation↗
PubMed1990

Coagulation profile in different stages of pregnancy and under consideration of placental expulsion in dairy cattle.

It was the aim of the present study to determine different parameters of blood coagulation in dairy cattle in the course of gestation (n = 19) and during 9 days post partum (n = 40). The coagulation profile comprised prothrombin time, partial thromboplastin time, thrombin time, fibrinogen concentration, and platelet count. Prothrombin time was shorter in the 2nd month of gestation (13.9 s) than in the 7th (15.2 s) month. A reduction of partial thromboplastin time towards the end of gestation by approximately 4 seconds was statistically insignificant (p greater than 0.05). A significant change of fibrinogen concentration was established over a period of 10 days ante partum. Immediately before parturition, fibrinogen level (484 mg/dl) increased compared to one (325 mg/dl) and two (343 mg/dl) days before calving. Cows whose calves were developed per vias naturales displayed pronounced differences of fibrinogen concentration. Animals with retained placenta showed significantly higher fibrinogen concentrations than cows with normal expulsion of the placenta on all days.

Animals↗
PubMed1977

Blood coagulations studies in pregnant patients with infective hepatitis.

Coagulation studies were made on 22 pregnant women with acute infective hepatitis and on 15 normal control pregnant women in third trimester. Fourteen hapatitis patients had clinical evidence of liver failure and all of them had a haemorrhagic diathesis; none of the patients without liver failure showed clinical evidence of haemostatic defects. Coagulopathy was present in most patients, its severity being greater in those with hepatic failure. Significant alterations were observed in bleeding time, whole blood clotting time, prothrombin time, thrombin time, plasma fibrinogen and serum levels of fibrinogen degradation products. The last three disturbances were most frequent in patients with liver failure. Increased fibrinolysis and disseminated intravascular coagulation also appeared to play a contributory role, particularly in patients with hepatic failure.

Adolescent↗
PubMed1999

Correlation of haemostatic abnormalities with tumour stage and characteristics in dogs with mammary carcinoma.

Sixty female dogs with untreated mammary carcinoma, comprising equal numbers of dogs in tumour stages I to IV, were evaluated for haemostatic abnormalities using the following tests: platelet count, prothrombin time, activated partial thromboplastin time, thrombin time, plasma activity of factor V, VIII and X, plasma concentration of fibrinogen, fibrin monomers and fibrinogen degradation products, and plasma antithrombin III activity. Two-thirds of all dogs had one or more haemostatic test abnormality of which the likelihood and frequency was increased in those with stage III and IV neoplasia. Haemostatic abnormalities were more frequently observed in dogs which had mammary tumours with distant metastases, extended tumour necrosis, inflammatory carcinomas, tumours fixed to underlying structures, or tumours in which there was penetration of the tumour capsule by tumour cells. As in humans with mammary carcinoma, these haemostatic abnormalities might be used as prognostic indicators, but their clinical importance remains unknown.

Adenocarcinoma↗
PubMed1985

Effects of apalcillin on platelet function in normal volunteers.

We investigated the effects of apalcillin on blood coagulation and platelet function. The drug was administered to 21 human volunteers in daily intravenous doses of 75, 150, and 225 mg/kg. These doses evoked abnormalities in platelet aggregation similar to those found with piperacillin and mezlocillin and less striking than those produced by carbenicillin and ticarcillin. Plasma coagulation as measured by prothrombin time, activated partial thromboplastin time, thrombin time, and fibrinogen concentration was not affected. There were consistent and major reductions in plasma antithrombin III activity, particularly at the two higher dose levels. Of 21 patients, 7 (33%) also manifested maculopapular skin rashes which resolved after discontinuation of the drug.

Adult↗
PubMed1975

Coagulation studies during experimental hemoglobinemia in humans.

Infusion of autologous hemolyzed blood in humans has served as a model for various experimental investigations for many years. Numerous studies have shown this model to be unattended by any adverse clinical reactions. In this study evidence of subclinical disseminated intravascular coagulation (DIC) was sought in normal humans infused with autologous hemolyzed blood. Hemoglobinemia was induced in 10 experiments by a single injection of frozen-thawed blood and in 4 experiments by such an injection of hemolysate followed by a 5-h maintenance infusion. Mean peak plasma hemoglobin following single dose injections was 540 mg/100 ml, while levels during continuous infusion averaged 240 mg/100 ml. The induction of hemoglobinemia was asymptomatic. Coagulation studies showed no significant alteration in prothrombin time, partial thromboplastin time, thrombin time, clottable fibrinogen, or WBC. Fibrin degradation products were not found. Platelet counts fell slightly in the 5-min postinfusion sample but returned to preinfusion levels within 30 min, suggesting a temporary sequestration of platelets rather than consumption. The induction of moderate brief experimental hemoglobinemia in normal subjects did not result in the development of demonstrable DIC.

Adult↗
PubMedDate not supplied

Disturbances of haemostasis in diabetes mellitus.

UNLABELLED: Diabetes mellitus is associated with disturbances in haemostasis that could contribute to the development of thrombotic complications.The present study was undertaken to determine the behavior of coagulation variables and fibrinolytic system in diabetes mellitus. Forty five diabetic patients and forty five matched controls were evaluated by doing the following haemostatic parameter, prothrombin time, partial thromboplastin time, thrombin time, coagulation factors assay II, VII, IX, & plasma fibrinogen, ADP-induced platelet aggregation, protein C, alpha2- antiplasmin, PAI and FDPs. Generally diabetic patients have high levels of fibrinogen, alpha2- antiplasmin, & PAI and lower level of protein C. Other haemostatic parameters did not show statistically significant difference between diabetic patients and control group. Significantly elevated levels of PAI, alpha2- antiplasmin together with low protein C level in diabetic patients may result in the disturbance of haemostatic balance favoring thrombotic events. CONCLUSION: High levels of plasma fibrinogen, alpha2A- antiplasmin with low plasma protein C activity could lead to a prothrombotic tendency in insulin dependent diabetic patients. Moreover, in non-insulin dependent diabetic patients, the above mentioned parameters together with high levels of ADP-induced platelet aggregation and plasminogen activator inhibitor may increase the risk of thrombotic complications. Obesity can be considered as an additional risk factor for development of thrombosis in diabetic patients.

Diabetes Mellitus↗
PubMed1982

Effect of acute ethanol intoxication on primary haemostasis, coagulation factors and fibrinolytic activity.

The effect of ethanol intoxication on haemostasis was studied by transection of mesenteric microvessels and liver resection in the rat. Plasma concentrations of alcohol were within the range of those found in ethanol intoxication in man. Bleeding time and blood loss were increased 1 h after ethanol administration, regardless of the utilized technique. A significant positive correlation existed between bleeding time following liver resection and bleeding time after simultaneous transection of a mesenteric arteriole and venule. Coagulation mechanisms, assayed by whole blood clotting time, APT time, one-stage prothrombin time, recalcification time, thrombin time, Owren's P & P test and determination of plasma factor V and fibrinogen levels, were not significantly changed in ethanol-intoxicated animals. Administration of alcohol did not affect fibrinolytic activity, while it inhibited significantly ADP and collagen-induced platelet aggregation in the rat.

Alcoholic Intoxication↗
PubMed1987

Coagulation changes in sickle cell disease in early childhood.

Measurements of the coagulation system were carried out in children with sickle cell disease (SCD) in both steady state and on the 1st day of painful crisis and were compared to age- and sex-matched healthy controls. No significant differences were found in prothrombin time, partial thromboplastin time, thrombin time, reptilase time, plasma fibrinogen, antithrombin III, factor VIII:C, ristocetin-cofactor (Ri-Cof) and platelet aggregation responses to ADP, collagen and adrenaline. Abnormal aggregation responses to ristocetin were noted in all patients with SCD when compared to controls. Daily measurements during the first 4 days of painful crisis showed significant elevation of fibrinogen and Ri-Cof and enhancement of aggregation to ADP and adrenaline by the 3rd day of crisis. It was concluded that the changes noted, rather than being primarily responsible for the onset of crisis, can only be secondary changes arising from the aetiological factors of crisis, i.e. stasis and acute-phase proteins.

Anemia, Sickle Cell↗
PubMed1981

Low-dose heparin in gynecologic surgery: effect on blood coagulation tests.

The laboratory control of low-dose heparin therapy is generally regarded as unnecessary. A laboratory study of the effects of low-dose heparin was performed using different methods: an amidolytic method and a method involving the inhibition of factor Xa in a coagulation test. Variations in partial thromboplastin time, recalcification clotting time, thrombin time and the plasma antithrombin III levels were also studied. These tests were repeated (days 0, 1, 3, 8) in 27 women between the ages of 27 and 62 years who were undergoing gynecological surgery. They received 5,000 IU of heparin either twice or thrice daily. There was no correlation between heparin levels in the blood and global clotting tests simultaneously performed. The plasma heparin levels varied between 0 and 0.15 IU/ml with both methods. A detectable heparin concentration on days 1, 3 and 8 was present in only half of the cases receiving the twice daily regimen. The plasma antithrombin III activity and concentration were not modified during treatment.

Adult↗
PubMed1982

Blood coagulation tests of gorillas.

In coagulation tests on five lowland gorillas, values within or close to the normal human range were found with the following tests: partial thromboplastin time, prothrombin time, thrombin time, factor XIII screen, factor II assay, factor V assay, fibrinogen and antithrombin III. Factor XII levels were very high. Factor VIII coagulant activity was moderately elevated but factor VIII antigen was very high in all and ristocetin cofactor activity was low in four of five.

Animals↗
PubMed2003

Pharmacokinetics and anticoagulant properties of the factor VIIa-tissue factor inhibitor recombinant Nematode Anticoagulant Protein c2 following subcutaneous administration in man. Dependence on the stoichiometric binding to circulating factor X.

Recombinant Nematode Anticoagulant Protein c2 (rNAPc2) is a potent (K(i) =10 pM), inhibitor of the factor VIIa/tissue factor (fVIIa/TF) complex that requires the prerequisite binding to zymogen or activated factor X (fX). In two double blind, place-bo-controlled, sequential dose-escalation phase I studies, rNAPc2 was found to be safe and well tolerated following single and repeat subcutaneous administrations in healthy human male volunteers at doses ranging from 0.3 to 5 micro g/kg. There was a dose-dependent elevation of the prothrombin time reaching almost 4-fold above the baseline value in the highest dose group that directly correlated with rNAPc2 plasma concentration. In contrast, there was little or no effect on the activated partial thromboplastin time, thrombin time or template bleeding time. The pharmacokinetic behavior of rNAPc2 revealed a dose-independent and prolonged elimination half-life (t(1/2)beta) with a mean of >50 hours. A high affinity interaction between rNAPc2 and plasma fX was shown to be essential for the prolonged t(1/2)beta in man using crossed immunoelectrophoresis and was confirmed by exploiting the considerably weaker interaction between rNAPc2 and bovine fX which resulted in an attenuated t(1/2)beta of approximately 1.5 hours in calves. The accumulated data suggests that rNAPc2 is safe and well tolerated following repeat subcutaneous administrations at doses up to 5 micro g/kg in healthy volunteers. In addition, the in vivo fate of rNAPc2 in man appears to be governed by its high affinity interaction with circulating fX. This data supports the continued development of this novel anticoagulant for the prevention and treatment of acute thrombotic disorders.

Animals↗
PubMed1979

Congenital deficiency of alpha 2-plasmin inhibitor associated with severe hemorrhagic tendency.

alpha(2)-Plasmin inhibitor (alpha(2)PI) is a recently characterized, fast-reacting plasmin inhibitor in human plasma that appears to play an important role in regulation of in vivo fibrinolysis. We report here a case of complete deficiency of alpha(2)PI in man. The patient, a 25-yr-old Japanese man, had a life-long severe bleeding tendency (hemarthrosis and excessive bleeding after trauma). The following tests were within normal limits: platelet count, bleeding time, thrombin time, prothrombin time, partial thromboplastin time, titers of known clotting factors, platelet glass bead retention, Factor VIII-related antigen, platelet aggregation by ADP, collagen and ristocetin, and clot retraction. Routine liver function tests were also normal. The only abnormal finding was that whole blood clot lysis was extemely rapid and was complete in 4-8 h. The concentration of plasma protease inhibitors, including alpha(2)-macro-globulin, antithrombin III, alpha(1)-antitrypsin, and C1INH, were all normal. The concentration of alpha(2)-PI in the patient's plasma, assayed by immunological methods, was <0.1 mg/100 ml (normal concentration, 6.1+/-0.88 mg/100 ml [mean+/-SE]) and functional assays showed a complete deficiency of alpha(2)PI. Addition of purified alpha(2)PI to the patient's whole blood completely corrected the accelerated fibrinolysis. The patient's parents, four siblings, and four other members of this family were asymptomatic, but the titers of alpha(2)PI in their plasmas were congruent with50% of normal pooled plasma. There were three consanguineous marriages in this family, and the alpha(2)PI deficiency appears to have been inherited as an autosomal recessive trait. We speculate that alpha(2)PI deficiency in this patient has led to uninhibited in vivo fibrinolysis that probably causes the severe hemorrhagic tendency. Thus, this study indicates the important role of alpha(2)PI in hemostasis.

Adult↗
PubMed1987

Functional vascular disorders: treatment with pentoxifylline.

A group of 11 female patients (mean age 33.7 +/- 8 years) with a clearly proven primary Raynaud's syndrome of up to five years' duration were subjected to a two-month oral treatment with 3 X 400 mg pentoxifylline per day. The following parameters were studied without and with exposure to cold conditions: hemodynamics (finger photoplethysmography), red cell deformability (filtration test), various clotting variables (prothrombin activity, antithrombin III, plasma fibrinogen, partial thromboplastin time, thrombin time, thrombelastogram), and clinical symptomatology. After treatment 7 of the 11 patients showed a distinct improvement of peripheral blood flow and of symptoms (decrease or removal of asphyxia attacks, pain, color change) under basal conditions, as well as after exposure to cold. Red cell filtration was significantly (p less than 0.05) improved, increasing by 35% under normal conditions and by 30% after exposure to cold. Positive changes were also found in respect to antithrombin III (increase) and plasma fibrinogen (decrease). The thrombelastogram was unchanged. Clinical and instrumental improvements were probably ascribable to better microcirculatory flow due to increased red cell deformability, reduced viscosity, and decreased fibrinogen, all capable of influencing in various degrees the blood flow at the microcirculatory level.

Adult↗
PubMed2001

Anticoagulant and antiprotease effects of a novel heparinlike compound from shrimp (Penaeus brasiliensis) and its neutralization by heparinase I.

Heparin is usually obtained from mammalian organs, such as beef lung, beef mucosa, porcine mucosa, and sheep intestinal mucosa. Because of the increased use of heparin in the production of low-molecular-weight heparin (LMWH), there is a growing shortage of the raw material needed to produce LMWHs. A previous report described the structural features of a novel LMWH from the shrimp (Penaeus brasiliensis). In order to compare anticoagulant and antiprotease effects of this heparin, global anticoagulant tests, such as the prothrombin time, activated partial thromboplastin time, thrombin time, and Heptest, were used. Amidolytic anti-Xa and anti-IIa activities were also measured. The relative susceptibility of this heparin to flavobacterial heparinase was also evaluated. The United States Pharmacopeia (USP) potency of shrimp heparin (SH) was found to be 28 U/mg. SH produced a concentration-dependent prolongation of all of the clotting tests and exhibited marked inhibition of FXa and FIIa. Heparinase treatment resulted in a marked decrease of the anticoagulant effects and neutralized the in vitro anti-IIa actions. However, the anti-Xa activities were only partially neutralized. Protamine sulfate was only partially effective in neutralizing the anticoagulant and antithrombin effects of SH. SH also produced marked prolongation of activated clotting time, which was neutralized by heparinase but not by protamine sulfate. These results suggest that SH is a strong anticoagulant with comparable properties to mammalian heparins and can be used in the development of clinically useful antithrombotic-anticoagulant drugs.

Animals↗