A Comparison between Effects of Estradiol Valerate and Low Dose Ethinyl Estradiol on Haemostasis Parameters

Ethinyl estradiol (EE) is still used to some extent as hormonal replacement therapy (HRT) in the climacteric period. As regards oral contraception, it is well known that the induced increase in cardiovascular disease is related to the estrogen component (invariably EE) in a dose-related fashion. Considerably lower doses of EE are needed in HRT compared to oral contraception.

To delineate and compare effects of EE and estradiol valerate (E2V) in doses needed in HRT on haemostasis parameters, 24 postmenopausal women were engaged in a study with an open cross-over design. The doses compared (10 μg EE and 2 mg E2V daily) are the lowest which eliminate climacteric symptoms in a majority of women. Unlike E2V, EE caused increased levels of factor VII: Ag, factor VIII: C and β-thromboglobulin, which may be changes towards hypercoagulability. Both estrogens decreased the AT III activity. Long-term administration (6 + 12 w) of the estrogens induced further changes in haemostatic parameters. 10 μg EE increased factor VII: Ag in contrast to 2 mg E2V. Furthermore both estrogens increased factor VIII :C and factor II-VII-X. A decrease in platelet count was induced by both EE and E2V.

Oral contraception and adjuvant estrogen therapy in men with prostatic carcinoma are known to imply an increased cardiovascular risk. It is noteworthy that the pattern of changes in haemostatic parameters induced by as little as 10 μg of EE is the same as seen after the administration of combined oral contraceptives or the substantially higher doses of EE given as adjuvant therapy to men with prostatic carcinoma.

Animal pharmacokinetics of inogatran, a low-molecular-weight thrombin inhibitor with potential use as an antithrombotic drug

Pharmacokinetics, excretion, and metabolism of inogatran, a low-molecular-weight thrombin inhibitor, were studied in the rat, dog, and cynomolgus monkey. After intravenous administration the half-life was short in all three animal species, due to a small volume of distribution and a relatively high clearance. At doses of 0.1-5 mumol kg-1, the mean residence time was about 10 min in the rat, 35 min in the dog, and 20 min in the cynomolgus monkey. The oral bioavailability of inogatran was incomplete, presumably due to a low membrane permeability, and dose dependent. The bioavailability was 4.8% at 20 mumol kg-1 and 32-51% at 500 mumol kg-1 in rats, 14% at 10 mumol kg-1 and 34-44% at 150 mumol kg-1 in dogs, and 2.1% at 1 mumol kg-1 in cynomolgus monkeys. The radioactivity excreted in urine and faeces was predominantly unchanged inogatran. After intravenous administration the percentage of the radioactivity recovered in faeces was about equal to or higher than the urinary recovery, which indicates biliary excretion of inogatran. After oral dosing, most of the dose was excreted in faeces, as expected from the estimates of oral bioavailability. The plasma protein binding of inogatran in rat, dog, and human plasma, was 20-28%. The blood-plasma concentration ratio was 0.39-0.56, indicating limited distribution into red blood cells.

In vitro effects of inogatran, a selective low molecular weight thrombin inhibitor

The thrombin inhibitor inogatran is a synthetic peptidomimetic with a molecular weight of 439 dalton. In vitro studies have shown that inogatran is a classical competitive inhibitor of the active site of thrombin with a Ki of 15 x 10(-9) mol/l. Inogatran doubles the thrombin clotting time in human plasma at 20 x 10(-9) mol/l, APTT at 1.2 x 10(-6) mol/l, and prothrombin time at 4 x 10(-6) mol/l. The effects on rat and dog plasma are similar although slightly weaker. IC50 for inhibition of thrombin-induced aggregation of human platelets is 17 x 10(-9) mol/l. Inogatran has no effect on platelet aggregation induced by ADP or collagen. Up to a concentration of 10 x 10(-6) mol/l inogatran does not inhibit t-PA-induced fibrinolysis as seen in an ECLT system. Inogatran has good selectivity for thrombin as compared to several other serine proteases occurring in the blood. It is concluded that the properties of inogatran in vitro make the compound suitable for further studies in animals and man.

Inogatran, a novel direct low molecular weight thrombin inhibitor, given with, but not after, tissue-plasminogen activator, improves thrombolysis

Coronary artery often reoccludes after therapy of acute myocardial infarction with recombinant tissue plasminogen activator rt-PA, most likely due to in situ thrombin generation during thrombolysis. Previous studies with high molecular weight thrombin inhibitors, such as hirudin, have shown variable improvement in the frequency of sustained thrombolysis. This study was conducted to examine the modulation of thrombolysis, indices of thrombin generation and activated partial thromboplastin time (APTT) by a novel low molecular weight direct thrombin inhibitor, inogatran. A stable occlusive intracoronary thrombus was created in 19 dogs. Nine dogs were given an intravenous bolus of saline (group A), and 5 dogs were given inogatran (group B) followed by rapid infusion of rt-PA (1 mg/kg over 20 min), whereas saline or inogatran was continuously infused for 2 hr. Five other dogs were given inogatran (bolus and continuous infusion) only after thrombolysis by rt-PA was obtained (group C). Time to reflow was similar in all dogs. None of the reperfused coronary arteries reoccluded in group B dogs (vs. 75% and 40% reocclusion rates in groups A and C, respectively, P < .02). Accordingly, the mean duration of reflow was > 120 min in group B dogs (vs. 39 +/- 7 and 44 +/- 14 min in group A and C dogs, respectively, P < .05). After infusion of inogatran, APTT was increased to 1.6 to 1.9 times the base-line value, and the changes in APTT were similar in group B and C dogs. Thrombin generation and activity, assessed by thrombin-antithrombin complex and fibrinopeptide A levels, increased in all dogs during thrombus formation. The increase in thrombin-antithrombin complex and fibrinopeptide A levels during thrombolysis was not evident in group B dogs. These data show that direct thrombin inhibition with inogatran, when initiated before rt-PA, results in sustained thrombolysis and only a modest increase in APTT. However, inogatran given after thrombolysis only partially prevents reocclusion because large amounts of thrombin generation occur during the early stages of thrombolysis.

Effects of inogatran, a new low-molecular-weight thrombin inhibitor, in rat models of venous and arterial thrombosis, thrombolysis and bleeding time

Inogatran (MW 439 Da), a new, selective, active site inhibitor of thrombin, was evaluated in three rat models of thrombosis. In the venous thrombosis model, inogatran dose-dependently inhibited thrombus formation with a > 80% antithrombotic effect at a plasma concentration of 0.45 mumol l-1. In the arterial thrombosis model, inogatran dose-dependently inhibited thrombus formation, preserved vessel patency and the mean blood flow. Acetylsalicylic acid (ASA) potentiated the effects of low plasma concentrations of inogatran in the arterial thrombosis model. In the model of rt-PA-induced thrombolysis of a thrombus in the carotid artery, inogatran improved the patency time and the cumulative blood flow during the two hour thrombolysis period more than rt-PA alone. At high therapeutic plasma concentration of inogatran, there was only a moderate prolongation of bleeding time compared with the control value. It is concluded that inogatran is an effective antithrombotic agent both in the venous and arterial thrombosis models and also as adjuvant to rt-PA in the thrombolysis model.

Thrombin inhibitors based on ketone derivatives of arginine and lysine

Much attention is currently focused on inhibitors of thrombin as potential anticoagulants. We have previously reported thrombin inhibitors based on fragments of fibrinogen containing a ketomethylene isostere at P1-P'1. We now expand on these early findings by reporting on tripeptide based inhibitors of thrombin containing arginine or lysine ketones at the C-terminus. A large variety of such ketones have been studied and compared in their ability to increase the thrombin time in human plasma. In the case of arginine or lysine ketones the order of activity (i.e. decreasing IC50 TT) was: alkyl ketones < beta-ketoesters < difluoro beta-ketoamides < alkyloxymethyl ketones < fluoroketones. Lysine analogues were generally found to be ca. ten-fold less active than their arginine counterparts. However, in the case of alpha-ketoesters the lysine derivatives were superior to all the types of arginine ketones studied (including the arginine alpha-keto ester derived thrombin inhibitor). A mechanistic explanation of the relative inactivity of the arginine alpha-keto ester derivative is proposed. All the highly electrophilic ketones were found to be slow-binding with thrombin.

Fibrinogen and plasminogen activator inhibitor-1 levels in hypertension and coronary heart disease. Potential effects of beta-blockade

The roles of fibrinolysis, fibrinogen, and plasminogen activator inhibitor-1 in the development of coronary heart disease are reviewed, and possible effects of long-term treatment with beta-blockade are discussed. Decreased fibrinolysis is associated with coronary artery disease, and coronary thrombus formation is the most frequent event precipitating myocardial infarction. Recently, it has also been shown that high levels of fibrinogen and plasminogen activator inhibitor-1 are predictors for myocardial infarction. Because beta-blockers are used to treat hypertension, angina, and myocardial infarction, it is important to determine the impact of beta-blockers on fibrinolysis. Several factors influence fibrinolysis. Some forms of stress and epinephrine infusions increase fibrinolysis, probably by stimulating beta 2-adrenoceptors. Nonselective beta-blockers may adversely affect this process, whereas beta 1-selective antagonists and those with intrinsic sympathomimetic activity may not. Since prostacyclin synthesis is correlated to increased fibrinolytic activity and since beta-blockers may moderate stress-induced reductions in prostacyclin formation, beta-blockers may have the potential to exert a beneficial effect on fibrinolysis in chronic stress situations. The net effect of beta-blockade is not easily predicted and probably depends on the nature of the stress (whether it is acute or chronic), the status of the patient, and the selectivity of the beta-blocker. Nevertheless, it remains a possibility that beta-blockers may exert a positive therapeutic effect in relation to coronary thrombosis by an action on fibrinolytic mechanisms.

Social influences and cardiovascular risk factors as determinants of plasma fibrinogen concentration in a general population sample of middle aged men

OBJECTIVE

To analyse the relation between fibrinogen concentration and social class and other social factors found to be related to mortality. The results regarding cardiovascular disease are unpublished, as yet.

DESIGN

Cross sectional population study.

SETTING

City of Gothenburg, Sweden.

SUBJECTS

639 Men from a population sample of 1016 men aged 50 in 1983. They were all employed and had no history of myocardial infarction or stroke. Fibrinogen values were available for all of them.

MAIN OUTCOME MEASURE

Fibrinogen concentration in relation to socioeconomic state according to occupation, and other social influences determined as number of people in the household and scores of social activities and activities in and outside the house.

RESULTS

Men with low scores for activities at home had a mean plasma fibrinogen concentration of 3.34 g/l (95% confidence interval 3.21 to 3.47), whereas those with an intermediate score had a mean concentration of 3.16 (3.00 to 3.32) g/l and those with a high score 3.02 (2.95 to 3.10) g/l. Similar inverse relations were noted for the two other activity scores and for occupational class (class 1 being unskilled and semiskilled workers and class 5 professionals and executives) and the number of people in the household. Smoking exerted a strong influence on fibrinogen concentration, the relations between fibrinogen concentration and social factors being evident only in non-smokers. The mean difference in fibrinogen value between the non-smokers with the lowest activity scores at home and those with the highest scores was 0.36 (0.19 to 0.54) g/l, and similar differences were seen for the two other activity scores. Multiple regression analyses showed smoking, body mass index, the sum of all activities (inverse relation), and diabetes to be independently associated with fibrinogen value, whereas occupational class (p = 0.81) and the number of people in the household (p = 0.09) were not.

CONCLUSIONS

Psychosocial influences seem to influence the coagulation system in the body in a way that is associated with cardiovascular disease and premature death.

Influence of metoprolol CR/ZOK on plasminogen activator inhibitor (PAI-1) in man: a pilot study

Recent primary and secondary preventive trials have shown that long-term metoprolol therapy reduces the risk of acute cardiovascular complications. To test whether part of this beneficial long-term effect may be due to effects on the fibrinolytic system, three pilot studies were performed; two in healthy individuals, and one in patients with mild hypertension or uncomplicated atrial fibrillation. The effect of metoprolol CR/ZOK (controlled release) 100-200 mg daily, on plasminogen activator inhibitor activity (PAI-1) in plasma was measured. In addition serum triglycerides and orosomucoid were analyzed. All the individuals were included in double-blind placebo controlled cross-over trials with treatment periods ranging from 4 days to 3 weeks. During metoprolol therapy PAI-1 values were reduced, while orosomucoid and triglyceride levels were unchanged. A linear inverse correlation was found between fibrinolysis and PAI-1 activity in plasma, indicating that PAI-1 activity serves as an indicator of fibrinolysis. PAI-1 activity and triglycerides were significantly correlated during placebo and metoprolol therapy. In conclusion, our results in these pilot studies suggest that metoprolol enhances fibrinolytic activity as seen by reduced PAI-1 activity. These results should be further confirmed and put into relation of clinical effects of the therapy.

Effect of disulfiram on the platelet function and fibrinolysis in healthy volunteers

Disulfiram was studied for platelet and fibrinolytic activity in 12 healthy volunteers of both sexes (age 23-75 years). Placebo was given for 7 days, followed by disulfiram, 800 mg for 2 days and 400 mg for an additional 12 days. Finally, there was another placebo period of 14 days. With the exception of an initial platelet activation on day 2, no significant effects were found on the platelet variables studied: platelet aggregation with collagen, ADP and adrenaline, beta-thromboglobulin and platelet factor 4. Treatment for 14 days with disulfiram resulted in a decreased euglobulin clot lysis time: from 421 +/- 82 to 246 +/- 41 min (p less than 0.01). After an initial increase, plasminogen activator inhibitor activity was slightly decreased on disulfiram, from 8.4 +/- 1.6 on placebo to 6.0 +/- 1.2 U/ml (p less than 0.05) after 14 days of treatment. Plasminogen, fibrinogen and alpha 2-antiplasmin were unchanged. It is concluded that disulfiram can increase fibrinolytic activity in healthy subjects.

Thrombosis after hip replacement. Relationship to the fibrinolytic system

Twenty-nine patients were operated on with the Charnley hip prosthesis. All the patients were given dextran 70 as thrombosis prophylaxis. Deep vein thrombosis (DVT) was diagnosed in 10 patients with the radioactive fibrinogen uptake test and phlebography. Variables of coagulation and fibrinolysis were studied before and after surgery. Tissue plasminogen activator (t-PA) activity in the plasma without venous occlusion decreased postoperatively, but there was no correlation with DVT. The t-PA activity in venous occlusion plasma was not reduced after surgery. Plasminogen activator inhibitor (PAI-1) levels were raised immediately postoperatively. There was a significant correlation between preoperative PAI-1 activity and development of postoperative DVT (P less than 0.05). Patients developing DVT had higher levels of PAI-1 postoperatively than patients not developing DVT. A defective fibrinolytic system, as defined by high PAI-1 activity, thus predisposed to postoperative DVT.

A comparison between effects of estradiol valerate and low dose ethinyl estradiol on haemostasis parameters

Ethinyl estradiol (EE) is still used to some extent as hormonal replacement therapy (HRT) in the climacteric period. As regards oral contraception, it is well known that the induced increase in cardiovascular disease is related to the estrogen component (invariably EE) in a dose-related fashion. Considerably lower doses of EE are needed in HRT compared to oral contraception. To delineate and compare effects of EE and estradiol valerate (E2V) in doses needed in HRT on haemostasis parameters, 24 postmenopausal women were engaged in a study with an open cross-over design. The doses compared (10 micrograms EE and 2 mg E2V daily) are the lowest which eliminate climacteric symptoms in a majority of women. Unlike E2V, EE caused increased levels of factor VII:Ag, factor VIII:C and beta-thromboglobulin, which may be changes towards hypercoagulability. Both estrogens decreased the AT III activity. Long-term administration (6 + 12 w) of the estrogens induced further changes in haemostatic parameters. 10 micrograms EE increased factor VII:Ag in contrast to 2 mg E2V. Furthermore both estrogens increased factor VIII:C and factor II-VII-X. A decrease in platelet count was induced by both EE and E2V. Oral contraception and adjuvant estrogen therapy in men with prostatic carcinoma are known to imply an increased cardiovascular risk. It is noteworthy that the pattern of changes in haemostatic parameters induced by as little as 10 micrograms of EE is the same as seen after the administration of combined oral contraceptives or the substantially higher doses of EE given as adjuvant therapy to men with prostatic carcinoma.

Thrombosis prophylaxis with low molecular weight heparin in total hip replacement

In a randomized prospective trial, the efficacy of low molecular weight heparin (LMWH) (Fragmin) and dextran 70 (Macrodex) in preventing deep vein thrombosis (DVT) in the legs was evaluated in 98 consecutive patients undergoing elective total hip replacement. The patients were randomly allocated to receive either 2500 anti-factor Xa units LMWH twice daily for 7 days, with the first dose given 2 h before surgery; or 500 ml dextran 70 twice during the day of operation, followed by a single infusion of 500 ml on the first and again on the third postoperative day. DVT was assessed by 125I-fibrinogen test for 2 weeks postoperatively, a positive test being followed by phlebography. DVT developed in 22 (45 per cent) of 49 patients receiving dextran 70 and in 10 (20 per cent) of 49 patients in the LMWH group (P less than 0.01). LMWH was thus statistically significantly better than dextran 70 in preventing DVT in the legs. It was not firmly established whether this benefit was also valid in the high ileofemoral region. Two patients with non-fatal pulmonary embolism were found in each group. Per- and postoperative blood loss and blood transfusion requirements were significantly lower in the LMWH group.

Ultrastructure and function of thrombocytes in a family with congenital bleeding tendency

Freshly isolated blood from controls and from three members of a family with congenital bleeding tendency were examined with respect to ultrastructure of platelets. The fixation protocol, which included tannic acid, permitted the visualization of substructures in the marginal bundle. Whereas nearly all platelets from the controls had a discoid shape, those from one of the patients (mother of the other two cases) were mostly flat or else roundish with two or three marginal bundles in different orientations. One portion of the thrombocyte fraction of each person was briefly exposed to adenosine diphosphate in order to activate the platelets and thereby to induce shape changes. Most platelets from the controls reacted as expected by rounding up and by projecting some pseudopods. A certain percentage (between 10 and 20%) of the microtubules in these activated platelets had 14 or even 15 protofilaments. The platelets from patients (and in particular the mother) either reacted by an abnormal bulging of the cytoplasm or did not react visibly at all. The microtubules retained their 13-subunit composition or in the abnormally reacted ones often had an open C-shaped cross-sectional profile. The bleeding tendency in this family might be due to a defect in the cytoskeleton of the platelet making it unable to react properly to stimuli.

Platelet reactivity, fibrinogen and smoking

40 young healthy male volunteers (20 habitual smokers and 20 non-smokers) were investigated with respect to platelet reactivity, plasma fibrinogen and coagulation factor VIII. Smokers had significantly lower systolic blood pressures and higher venous platelet counts. The results for ADP-induced platelet aggregation, plasma concentrations for the 2 alpha-granule proteins, beta-thromboglobulin and platelet factor 4, did not differ between the 2 study groups involved; nor was there any difference between serum thromboxane B2 formation or plasma factor VIII:C activity. However, as compared to non-smokers, plasma fibrinogen levels were significantly higher among the smokers.

Early activation of humoral proteolytic systems in patients with multiple trauma

Coagulation, fibrinolytic, kallikrein, and complement systems were studied in 20 patients with multiple trauma. Three of four patients with a trauma score less than 10 on hospital arrival died, compared to one of 16 with a score over 10. Five patients developed disseminated intravascular coagulation. Signs of activated cascade systems were evident in most patients on hospital arrival. Changes were not related to trauma score, but patients with an arterial pressure below 110 mm Hg had significantly lower levels of antithrombin III and alpha 2-antiplasmin than those with higher BP. This study confirms that the cascade systems are activated very soon after multiple trauma.

A sensitive assay for tissue plasminogen activator activity in plasma, using adsorption on lysine-sepharose

Tissue plasminogen activator (t-PA) in plasma was separated from inhibitors by adsorption on lysine-Sepharose. It was then determined indirectly by measuring the plasmin generated from plasminogen with poly-lysine as stimulator, in a chromogenic, parabolic rate assay. The reaction proceeded with tissue plasminogen activator and plasmin(ogen) adsorbed on the gel, and followed the kinetics described for similar parabolic rate assays in soluble systems. The assay was standardized against melanoma plasminogen activator (m-PA) and had the sensitivity range of 0.001-0.020 IU (4-80 pg). Anti-m-PA IgG quenched the activity generated in plasma on venous occlusion and part of the activity in pre-occlusion plasma. The method was sensitive to purified urokinase. The basic plasma values in resting normal individuals were: mean 0.08, range 0.01-0.26 X 10(3) IU/l (n = 19), and after 20 min of venous occlusion: mean 2.48, range 0.24-4.34 X 10(3) IU/l (n = 10). The assay correlates well with a fibrin plate method, r = 0.96.

Fibrinopeptide A and intravascular coagulation in normotensive and hypertensive pregnancy and parturition

Fibrinopeptide A (FpA), fibrin monomers, fibrinogen, fibrin degradation products (FDP) aand platelets have been studied during pregnancy, parturition and during toxemia and compared with normal non-pregnant controls in order to evaluate thrombin activity under these conditions. We found a significant rise in fibrinopeptide A levels in late pregnancy and even more so during parturition with a maximum immediately after placental expulsion. We also found elevated FpA levels in toxemic patients, but no significant differences from normal pregnancies. Fibrin monomers were more often elevated during delivery and toxemia during normal pregnancy. One case report concerning a patient with deficient thrombin activation and heavy postpartum bleeding is added. Our studies indicate an increased thrombin activity and fibrinogen turnover in both normal and toxemic pregnancies. During normal childbirth, coagulation activity seemed to reach a maximum immediately after placental separation.

Effects of tranexamic acid and local fibrin deposition of fibrinolysis and granulation tissue formation in preformed cavities

The effects of locally deposited fibrin and of tranexamic acid-induced antifibrinolysis on forming granulation tissue were studied in the light of a recently developed method for treatment of postoperative fistulas by occlusion with a fibrin clot. Perforated teflon cylinders, either empty or fibrin-filled, were implanted subcutaneously in rats and extracted after 2 weeks. Fibrin deposition was found to stimulate granulation tissue ingrowth into the cylinders but it did not change the fibrinolytic activity in the granulation tissue. A significantly higher fibrinolytic activity was, however, found in the tissue fluid collected from the space between the granulation tissue and the implanted fibrin clot compared to tissue fluid from cylinders implanted empty. Tranexamic acid significantly reduced the fibrinolytic activity on the granulation tissue and delayed lysis of the implanted fibrin clot. It also reduced granulation tissue ingrowth but it did not abolish the positive effects of the clot on granulation tissue formation.

Hereditary ring sideroblastic anaemia and Christmas disease in a Swedish family

The association of hereditary ring sideroblastic anaemia with Christmas disease in a Swedish family is described. We have studied the transmission of the sideroblastic trait, in relation to HLA groups and Christmas disease, and also evaluated the erythrocyte morphology, uroporphyrinogen-I-synthetase activity and S-ferritin for the detection of latent cases of ring sideroblastic anaemia. The proband had ring sideroblastic anaemia, Christmas disease and haemochromatosis. 3 cases of ring sideroblastic anaemia were found among the 12 family members studied. Using the factor IX deficiency as a marker of the X chromosome, it appeared that autosomal transmission of the sideroblastic trait was most likely. The sideroblastic trait did not seem to be linked to HLA-A3-alloantigen. Erythrocyte morphology was normal in all non-anaemic subjects. S-ferritin was found to be increased in all 3 cases of sideroblastic anaemia as well as in 1 non-anaemic relative. Erythrocyte uroporphyrinogen-I-synthetase was elevated in 10 of the 12 family members; those with sideroblastic anaemia had the highest values indicating that uroporphyrinogen-I-synthetase is of importance in the disturbed haem-synthesis of ring sideroblastic anaemia. This interpretation is supported by the positive correlation between S-ferritin values and the uroporphyrinogen-I-synthetase activity.

Influence of local fibrin deposition on granulation tissue formation. A biochemical study in the rat

A recently developed method for occlusion of fistulas with a fibrin clot initiated studies of the effects of deposited fibrin on granulation tissue formation. Perforated Teflon cylinders, empty or fibrin-filled, were implanted subcutaneously in rats for 2, 3 and 4 weeks and the composition of the ingrowing granulation tissue was followed by sequential biochemical analysis. The concentration of fat and water and the cellularity, measured as DNA concentration, were the same throughout the period studied in the granulation tissue from cylinders implanted empty and fibrin filled. After 2 weeks of implantation, the collagen concentration was higher in fibrin-filled cylinders than in cylinders implanted empty. The higher collagen concentration was explained by a higher proportion of mature collagen-synthesising cells. After 3 and 4 weeks of implantation there was no difference in the collagen concentration between cylinders implanted empty and fibrin filled.

Influence of fibrin clots on development of granulation tissue in preformed cavities

To examine the influence of fibrin clots, perforated Teflon cylinders have been implanted subcutaneously in rats. Fibrin clots made from both species specific fibrinogen and from an non-species specific preparation, together with ingrowing granulation tissue, kept the implanted cylinder filled during the four week study period. This was valid for both concentrations investigated. Interaction between granulation tissue and fibrin clot differed between the two fibrin types.

Prostacyclin infusion during extracorporeal circulation foe coronary bypass

The effects of prostacyclin on whole blood platelet count, blood coagulation factors, and postoperative bleeding were investigated in 20 patients undergoing aorta-coronary bypass. Eleven patients received heparin 2 mg/kg and prostacyclin 50 ng/kg/min during cardiopulmonary bypass (CPB). Nine patients received only heparin 3 mg/kg. CPB was by roller pump and bubble oxygenator primed with Ringer's acetate. Hypothermia to 28 degrees C was induced. In the control group, platelet count, corrected for hemodilution, was 70% +/- 15% (mean +/- SD) of pre-CPB value after 30 minutes of bypass and remained at this level 1 hour after CPB. In the prostacyclin group, the platelet count after 30 minutes was 85% +/- 17%, after 120 minutes 111% +/- 20%, and 1 hour after CPB 92% +/- 17%. There was a significant difference between the groups (p less than 0.05) from 60 minutes of CPB up to 1 hour after CPB. Prostacyclin allowed reduction of the heparin dosage while retaining anticoagulation as measured by activated coagulation time (ACT), fibrinopeptide A, and fibrinogen determinations. The ACT was more than 900 seconds in the prostacyclin group after 30 minutes of CPB, as compared to 523 +/- 118 seconds (p less than 0.05) in the control group. This difference diminished later during CPB. In the prostacyclin group, arterial blood pressure was 30 mm Hg or less during the first hour of CPB and the systemic vascular resistance was half of that in the control group. All patients survived. There were no clinical signs of neurologic damage. Postoperative bleeding was 352 +/- 61 ml in the prostacyclin group and 550 +/- 338 ml (NS) in the control group.

alpha 2-Antiplasmin and alpha 2-macroglobulin--the main inhibitors of fibrinolysis--during the menstrual cycle, pregnancy, delivery, and treatment with oral contraceptives

alpha 2-Antiplasmin and alpha 2-macroglobulin have been studied during the menstrual cycle, pregnancy and parturition in healthy women, and during use of various types of contraception in both healthy and diabetic women, and compared with a reference group of healthy men and women. alpha 2-Antiplasmin showed a slight sex difference, with higher values in women. The luteal phase of the menstrual cycle showed slightly higher values than the other phases. alpha 2-Antiplasmin increased during pregnancy, decreased (probably due to consumption) during labor and increased again in the puerperium. Treatment with neither combined contraceptive pills nor low dose progestogen pills gave any changes in alpha 2-antiplasmin. alpha 2-Macroglobulin showed low values during menstruation. The increase during pregnancy and treatment with combined contraceptive pills is in accordance with earlier findings. It is concluded that synthesis and metabolism of alpha 2-antiplasmin are under hormonal influence. The role of alpha 2-antiplasmin in the decreased fibrinolysis in pregnancy is discussed.

Pseudoendothelium formation in expanded polytetrafluoroethylene grafts implanted in the inferior vena cava of normal and defibrinogenated dogs

The outgrowth of endothelial cells in an expanded polytetrafluoroethylene graft implanted in the canine inferior vena cava was studied by scanning electron microscopy. The adjacent endothelial cells of the vena cava started to invade the anastomotic area three days after the implantation and reached approximately the central part of the 2-cm-long graft after 21 days. There was no obvious difference in the process of endothelialization between the control group and the moderately defibrinogenated group, in which the fibrinogen concentration was at most 0.72-0.87 gm/L. A slight delay in the outgrowth of endothelial cells was noted within the first seven days in the severely defibrinogenated group, in which the fibrinogen concentration was below 0.40 gm/L. After 70 days, all grafts were completely covered by endothelial cells. The structural difference of the mural thrombus resulting from reduced fibrin formation might be a major factor influencing the endothelium formation.

Acute hepatitis non-A, non-B following administration of factor VIII concentrates

A retrospective survey on clinical hepatitis in patients with bleeding disorders was performed. Nine episodes of hepatitis non-A, non-B occurred in 8 out of 20 patients (40%) with mild hemophilia A or von Willebrand's disease, who had been treated with commercial factor VIII concentrates. Only two episodes of hepatitis B occurred during the study period. The non-A, non-B attack rate after the first treatment was 40% with factor VIII concentrate obtained from large plasma pools (= 2,000 donors) including professional plasma donors as compared to 8% after treatment with factor VIII concentrate obtained from smaller (100-250 donors) plasma pools from Scandinavian donors.

Haemostatic clot formation at anastomosis of synthetic venous graft in defibrinogenated dogs: a scanning electron microscopic study

A segment of the inferior vena cava was replaced by an expanded polytetrafluoroethylene graft in 13 dogs. Five of them served as a control group, while the other 8 were moderately or severely defibrinogenated with subcutaneous batroxobin. Plasma fibrinogen decreased to extremely low values throughout the experiment in the defibrinogenated dogs except in the moderately treated group in which it temporarily rose to 0.72-0.87 g/l on the first postoperative day. Scanning electron microscopic observations of the haemostatic clot formed at the anastomoses of the graft revealed no significant morphological differences in platelet adhesion and/or aggregation between the three groups. These findings confirmed that platelets play a key role in primary haemostasis during defibrinogenation. The fibrin network was slightly diminished and only short fibrin filaments could be seen in the moderately and severely defibrinogenated groups respectively. These differences in composition of the clots are discussed in relation to their haemostatic capacity.

Pseudointima in expanded polytetrafluoroethylene graft implanted in the inferior vena cava of normal and defibrinogenated dogs

The pseudointimal formation in an expanded polytetrafluoroethylene graft implanted in the canine inferior vena cava was studied by light and transmission electron microscopy. Five of 6 grafts in the control group and all of the 10 grafts in the batroxobin-defibrinogenated group were patent, and provided for the investigation. The thickness of the mural thrombus formed within 3 days was significantly decreased in the severely defibrinogenated dogs, in which the fibrinogen concentration was below 0.40 gm/L, as compared to the controls and the moderately defibrinogenated dogs, in which the fibrinogen concentration was at highest 0.72-0.87 gm/L. In spite of reducing the fibrinogen concentration to unmeasurable levels after 3 days, there was no obvious difference in the process of pseudointimal formation between the moderately defibrinogenated dogs and the controls. In the severely defibrinogenated dogs, loose and spongoid mural thrombus required a longer time to be reorganized.

Intrapleural instillation of streptokinase. Effects on systemic fibrinolysis

Ten consecutive patients aged 25 to 75 with postoperative empyema or hemothorax conventionally treated with drainage without sufficient effect were given intrapleural instillations of streptokinase (Kabikinase, 250,000 IE) for 4 hours). The effects on systemic fibrinolysis were studied. Venous blood samples for determination of fibrinolytic activity on fibrin plates, plasminogen, alpha 2-antiplasmin, alpha 2-macroglobulin, fibrinogen, fibrin(ogen) degradation products (FDP) and thrombin time were taken before instillation, after instillation and then after 24 hours. Preinstillation values were compared to the values 4 and 24 hours after instillation with Student's paired t-test. There were no differences in fibrinolytic activity, alpha 2-macroglobulin and thrombin time. There was a slight increase in plasminogen, alpha 2-antiplasmin and fibrinogen, probably due to an acute phase reaction. Fibrin degradation products showed an increase with border line significance. These changes are not consistent with generalized fibrinolysis, and it is concluded that intrapleural instillations of streptokinase can be given safely in the early posttraumatic or postoperative period.

Natural protease inhibitors to fibrinolysis in liver diseases

The newly discovered alpha 2-antiplasmin and some inhibitors of fibrinolysis were measured in 40 patients with liver diseases. alpha 2-antiplasmin was low in liver cirrhosis, but unchanged in cholestasis when compared with controls.

Determination of fast-acting plasmin inhibitor (alpha2-antiplasmin) in plasma from patients with tendency to thrombosis and increased fibrinolysis

The physiologically important alpha2-antiplasmin has been measured by aid of a chromogenic tripepetide substrate. Low values in patients' plasmas are found in situations with increased fibrinolysis such as streptokinase therapy and liver cirrhosis, whereas high values are found postoperatively, postpartum and after an acute thrombosis.

Determination of a new rapid plasmin inhibitor in human blood by means of a plasmin specific tripeptide substrate

A method for determination of antiplasmin activity is presented. Plasmin and plasma are incubated, and the remaining plasmin activity is measured spectrophotometrically by means of the plasmin specific tripeptide substrate H-d-Val-l-Leu-l-Lys-p-nitroanilide. The method is simple, rapid and easily automatized. By the immunoadsorption technique, and with the aid of purified substances it is shown that the measured activity is mainly due to a new antiplasmin [2,4] and possibly to some extent to alpha1-antitrypsin and C1-esterase inhibitor have no antiplasmin activity in the method. Heparin and epsilonaminocaproic acid interfered with the assay.

Multiple arterial occlusions and hypertension probably caused by an oral contraceptive: a patient in whom the development of renovascular hypertension has been followed

An 18-year-old woman taking an oral contraceptive was admitted to hospital because of a stroke due to occlusion of three branches of the right middle cerebral artery. She later developed renovascular hypertension due to occlusion of one of two renal arteries on the right side. Occlusion of the ceoliac artery was also found. The circumstances suggest that the occlusions were caused by multiple emboli, the source of which could not be identified. The kidney with the circulatory disturbance was shown to have a persistent abnormal renin secretion three and six months after the stroke, but the peripheral renin level was lower at the second investigation. Cardiac function studies revealed an alarming degree of left ventricular hypertrophy, and satisfactory blood pressure control could not be maintained despite increasing antihypertensive therapy. Surgical corrrction of the circulatory disturbance promptly led to normotension without drugs, and the patient has remained normotensive during the postoperative observation period of twelve months. The oral contraceptive was probably responsible for precipitating the vascular occlusions, but no predisposing factors or warning symptoms were present to identify this patient as being at risk.

Incidence of viral hepatitis after administration of factor IX concentrates

A high frequency of viral hepatitis has been reported after treatment with the human factor IX concentrate 'Konyne'. Clinical trials with 'Konyne' and a similar factor IX concentrate, called 'Preconativ', was started in Sweden 1969. During the first 2 years, 26 patients were treated with either one or both preparations. Nine patients developed viral hepatitis within 6 months after treatment. 'Preconativ' alone was introduced on the Swedish market in 1971. During the period 1971-1974, another 26 hemophiliacs were treated but only two cases of hepatitis have occurred. Selection of donors and screening for hepatitis B surface antigen in donor blood used for the manufacturing of 'Preconativ', might be contributing factors to this low hepatitis incidence.

Disseminated intravascular coagulation and congenital neuroblastoma

A newborn infant with congenital neuroblastoma complicated by disseminated intravascular coagulation is described. At birth the infant showed liver and spleen enlargement and shortly thereafter malignant cells were found in the bone marrow. On the fifth day of life the infant started to bleed and coabulation analysis indicated disseminated intravascular coagulation. Heparin therapy corrected the coagulation anomaly and irradiation and chemotherapy temporarily improved the general condition of the infant. The infant finally succumbed from tis primary neoplastic disease.