von Willebrand factor and factor VIII in renal transplant recipients under immunosuppression with cyclosporine and steroids. Sequential measurements over 4 months in 17 patients

In 17 consecutive cadaver kidney transplant recipients treated with cyclosporine (CsA) and steroids, the median of antigenic and functional levels of von Willebrand factor (vWF) and factor VIII (FVIII) before transplantation were elevated (vWF:Ag: 206%, vWF:RCof: 202%; FVIII:Ag: 248%, FVIII:C: 224%; normal values 50-150%). Sequential measurements after transplantation and during CsA treatment revealed a transient significant increase of median values with highest amounts of vWF:Ag of 362% (2 p less than 0.0001), FVIII:Ag of 398% (2 p less than 0.001) and FVIII:C of 360% (2 p less than 0.0001) (Friedman test). vWF:RCof did not show statistically significant changes. After 4 months, levels of vWF and FVIII comparable to those obtained before transplantation were observed. In univariate statistical analysis no correlation was found between vWF of FVIII on the one hand and plasma creatinine levels, CsA dose or CsA whole blood through levels on the other hand. However, multivariate statistics revealed to some extent a positive influence of CsA blood levels on vWF:Ag levels. Patients with vascular rejection or chronic CsA nephrotoxicity showed significantly lower levels of vWF:Ag as compared with patients without endothelial cell damage in the kidney (2 p less than 0.05). However, the difference in vWF:Ag levels already existed before transplantation. In contrast to recent reports, plasma vWF levels were not indicative of vascular injury in kidney graft recipients nor was the marked elevation of vWF and FVIII associated with thromboembolic complications ascribed to CsA treatment.

A randomized comparative study of artemisinine (qinghaosu) suppositories and oral quinine in acute falciparum malaria

In adult patients with acute falciparum malaria in Ho Chi Minh City, Vietnam, a more rapid reduction in parasite count (50% clearance in 11.3 h) and complete clearance (41.8 h) was obtained in 32 adult patients randomly assigned to received artemisinine suppositories than was obtained with 30 patients receiving oral quinine (20.8 h and 68.1 h). There were higher degrees of resistance (RII, 3 cases; RI early, 1 case) with quinine than with artemisinine but in a subgroup of patients quinine reduced parasitaemia as rapidly as artemisinine (50% clearance 13.6 h and 10.1 h respectively). Recrudescence (RI, delayed), occurred in 16 patients receiving artemisinine compared with 6 receiving quinine. Artemisinine suppositories, because of ease of administration, efficacy, and lack of side effects or risk of overdose, have advantages for the early treatment of falciparum malaria by possibly reducing the morbidity and mortality associated with a high or sustained parasitaemia.

Epigenetic and genetic factors affect transgene methylation imprinting

In some lines of transgenic mice, the methylation of MspI sites within or adjacent to the transgene locus is affected by the sex of the parent from which the transgene is inherited. These differences are consistent with a role for DNA methylation in genome imprinting. In a previous report, we noted that in one such line, all offspring of females exhibited hypermethylation of the transgene while only some offspring of males carried a hypomethylated transgene. In this report, we provide evidence that this phenomenon is controlled by at least two factors, one of which acts in cis and is dependent on the transgene locus, and one of which acts in trans and is supplied by the maternal genome. We also provide evidence that there are genetic differences between inbred mouse strains in the trans-acting factor.

Effect of protein malnutrition and maternal caffeine intake on the growth of fetal rat brain

Pregnant dams were divided into two subgroups on day 10 of gestation. Half were fed a 20% protein diet and the other half an 8% protein diet. A second group also subdivided was pair-fed with rats of the first group. Their diet was supplemented with caffeine in amount calculated to provide daily doses of 2 mg/100 g body weight. On days 18, 20, and 22 randomly selected dams were injected with 3H-thymidine intraperitoneally and 1.5 h later their fetuses were delivered surgically in order to determine the rate of DNA synthesis along the gestation. The rest of the fetuses were delivered surgically on day 22. Pups' brains were rapidly removed and DNA, RNA, protein and 3H-thymidine uptake were studied. Average body weights of the fetuses in the caffeine-supplemented control group were smaller than those of the noncaffeine group. Effects of caffeine that were similar in both diet groups included a decrease in brain DNA content and concentration and an increase in brain protein content and concentration. However, the percent decrease and increase, respectively, was different depending on the nutritional status. DNA synthesis was not affected by malnutrition or caffeine supplementation on day 18 of gestation. Caffeine's effect on the rate of DNA synthesis was different on day 20 of gestation depending on nutritional status. Caffeine supplementation resulted in a decrease in DNA synthesis in both groups on day 22 of gestation. These data indicate that caffeine intake during pregnancy produces differential effects on fetal rat brain depending on dietary protein content.

Phenobarbital increases the theophylline requirement of premature infants being treated for apnea

To determine the effect of phenobarbital sodium therapy and subependymal intraventricular hemorrhage (SEp-IVH) on the theophylline requirement of premature infants suffering with apnea and seizure activity, we compared three groups of patients as follows: group 1, those with apnea of prematurity (ten patients); group 2, those with apnea and SEp-IVH (ten patients); and group 3, those with apnea, SEp-IVH, and seizure activity for which they were receiving phenobarbital therapy (nine patients). Patients in groups 1 and 2 required lower dosages and blood levels of theophylline to control their apnea than did those in group 3, who required higher dosages and blood levels of methylxanthines. Theophylline dosages and blood levels did not significantly differ between groups 1 and 2. In group 3, the theophylline requirement for control of apnea was significantly increased after initiation of phenobarbital therapy. There seems to be a direct correlation between the increased requirement for theophylline and concomitant phenobarbital administration. The data suggest that phenobarbital increases theophylline requirement when treating neonatal apnea.

Heparin cofactor II: purification and antibody production

Heparin cofactor II (HCII) was purified from plasma to homogeneity. The procedure includes adsorption with (A1)OH3, fractionation with polyethylene glycol 6000, chromatography on QAE-Sephadex A-50, on heparin-Sepharose 4B and on Sephadex G-150. QAE-Sephadex A-50 chromatography provides a good separation of HCII from antithrombin III (AT) and most contaminants having a heparin affinity similar to that of HCII. HCII is eluted at 0.28 M NaCl from the heparin-Sepharose column. After gel filtration on G-150, contaminating AT was removed by immunoadsorption. Purified HCII shows an apparent Mr of 66,500 daltons as analyzed on SDS-polyacrylamide gel and 62,100 daltons by ultracentrifugation. Antibodies to HCII were raised in rabbits. Former antisera mostly directed to a contaminating protein were used to remove it from the HCII preparation. Antibodies to HCII were made monospecific by immunoadsorption on HCII-free plasma linked to Sepharose 4B. Since many functional AT assays have neglected the presence of HCII in plasma, antibodies to HCII using as immunoadsorbent will provide a more specific test for AT.

Antithrombin III Basel. Identification of a Pro-Leu substitution in a hereditary abnormal antithrombin with impaired heparin cofactor activity

Antithrombin III Basel is a hereditary abnormal antithrombin with normal progressive inhibition activity (normal reactive site) and reduced heparin cofactor activity (impaired heparin binding site). Structures of antithrombin III Basel and normal antithrombin III isolated from the same patient were compared by peptide mapping using the dimethylaminoazobenzene isothiocyanate precolumn derivatization technique. Of the approximately 50 tryptic peptides of normal and abnormal antithrombin III, one peptide comprising residues 40-46 had a different retention time in reversed-phase high performance liquid chromatography. The amino acid sequence of the peptide from antithrombin III Basel had a single substitution of Pro (normal) by Leu (abnormal) at position 41. This substitution is close to an Arg (residue 47) and a Trp (residue 49) which have previously been shown to be critical for heparin binding by antithrombin III. Although additional amino acid substitutions in antithrombin III Basel cannot be ruled out, this Pro-Leu replacement could cause a conformational change by increasing both the helical structure and the hydrophobicity around residue 41. These data suggest that: (i) the heparin binding site of antithrombin III encompasses the region containing residues 41, 47, and 49; and (ii) the impaired heparin cofactor activity of antithrombin III Basel is likely due to a conformational change of the heparin binding site induced by the Pro-Leu substitution at position 41.

Methodology and clinical significance of heparin cofactor II. Probable heparin cofactor II deficiency in a patient with cerebrovascular thrombosis

HC II was functionally determined by thrombin inhibition in the presence of heparin in AT III-free plasma prepared by immunoadsorption on anti-AT III-Sepharose 4B column. HC II antigen concentration was assayed using specific antibodies to HC II. Simultaneously, AT III was measured. Plasma levels of HC II and AT III were determined in 110 patients with thrombotic tendency and two patients with obstetric complications and DIC. Highly significant correlations between activity and antigen prove the suitability of the methods. Reduced levels of HC II to about 50% with normal AT III values were repeatedly found in one patient with thrombotic tendency. The course of AT III and HC II during the process of DIC suggests that HC II may function as a thrombin inhibitor reserve when AT III becomes subnormally low.

Association of hereditary heparin co-factor II deficiency with thrombosis

A family was investigated for heparin co-factor II deficiency. Three of the five members examined had had thrombosis and their levels of heparin co-factor II were reduced to 50%. All five members had antithrombin III levels within the normal range. Analysis on crossed immunoelectrophoresis showed no qualitative abnormality of patient heparin co-factor II antigen. Since heparin co-factor II activity and concentration were reduced to the same extent, the deficiency was due to reduced protein synthesis.

Purification of antithrombin 'Vicenza': a molecule with normal heparin affinity and impaired reactivity to thrombin

Antithrombin III (AT) 'Vicenza', a previously described dysfunctional AT associated with familial thrombosis, has been isolated by heparin affinity chromatography. The purified molecule has been investigated by SDS-polyacrylamide gel electrophoresis and crossed immunoelectrophoresis after incubation with different amounts of thrombin. A normal affinity for heparin has been demonstrated. However, evidence is produced that AT 'Vicenza' poorly inhibits thrombin. Present data suggest that AT 'Vicenza' consists of a population of two molecules, half of which does not form a complex with thrombin however and loses its heparin affinity upon thrombin treatment.

Factor VIII (procoagulant activity VIII:C, and antigen VIII:CAg, related antigen VIIIR:Ag and ristocetin cofactor VIIIR:Cof) in intensive care patients with clinically suspected disseminated intravascular coagulation (DIC)

VIII:C, VIII:CAg, VIIIR:Ag and VIIIR:Cof were determined repeatedly in nine shock patients with suspected DIC and in five patients with uncomplicated acute myocardial infarction and compared with the clinical course and the severity of DIC as reflected by a score based on six routine coagulation and fibrinolysis parameters. All shock patients showed high levels of VIIIR:Ag, VIIIR:Cof, and VIII:CAg, averaging fivefold to sixfold the normal level, of VIII:C averaging threefold the normal level. VIIIR:Cof and VIIIR:Ag significantly correlated in both groups of patients. In shock patients, VIII:C values were lower than VIII:CAg and varied between 40-90% of VIII:CAg. There were significant negative correlations between the DIC score on the one hand and ratios of VIII:C/VIIIR:Ag, VIII:C/VIII:CAg, and VIII:CAg/VIIIR:Ag on the other. The two patients who died from irreversible shock had the highest DIC score and lowest ratios of VIII:C/VIIIR:Ag and VIII:CAg/VIIIR:Ag as well as VIII:C/VIIIR:Cof and VIII:CAg/VIIIR:Cof. Released VIIIR:Ag multimers possess the ristocetin cofactor activity. In DIC, VIII:CAg is partially proteolyzed, however, less than VIII:C. The quotient VIII:C/VIIIR:Cof or VIII:C/VIIIR:Ag is a good indicator of the severity of DIC and may have important prognostic value.

Heparin cofactor II determination--levels in normals and patients with hereditary antithrombin III deficiency and disseminated intravascular coagulation

A technique is described to completely remove antithrombin III (AT) from small amounts of human plasma by immunoaffinity chromatography on antibodies against human AT linked to Sepharose 4B. The level of heparin cofactor II (HCII) was not affected by the immunoadsorption. HCII activity was then determined by measuring the rate of human thrombin inhibition by 3 ways: a) activation with heparin in AT-free plasma, b) activation with dermatan sulfate in normal plasma and c) activation with dermatan sulfate in AT-free plasma. The normal range of HCII varied between 0.7-1.5 U/ml, as compared to a normal plasma pool containing by definition 1 U/ml. Highly significant correlations between assays as obtained from 40 normal plasmas proved the suitability of the 3 assays, although the progressive thrombin inhibition by AT, when not removed, contributed about one fifth to the thrombin inhibition by HCII in the presence of dermatan sulfate. There were also highly significant correlations between HCII activity and antigen, as determined by rocket immunoelectrophoresis using specific antibodies against HCII. Levels of HCII and AT were examined in 7 patients with hereditary AT deficiency and 7 patients with disseminated intravascular coagulation (DIC). In hereditary AT deficiency, whereas the AT activity was reduced by half, levels of HCII activity and antigen were in the normal range. In DIC, a parallel decrease of HCII and AT suggests that HCII may participate in the inhibition of thrombin released during DIC and thus provides an inhibitor reserve, once the AT level becomes subnormally low.

Fifteen coagulation and fibrinolysis parameters in diabetes mellitus and in patients with vasculopathy

Fifteen haemostasis parameters have been measured in 48 normal persons, 36 diabetic without and 44 with complications and 27 with peripheral arterial disease. Since the patient groups are older than normals, part of the differences are due to age. However, the differences are significant between normals and patients. They become highly significant for the diabetics with complications and nephropathy (Table 7). In diabetics without complications factor VIII functions, fibrinogen and thrombin time are related to age whereas there is a negative correlation for the fibrinolytic activity and antithrombin III. The diabetic complications shade off the correlations, which subsist only for VIIIR:CoF, VIIIR:Ag, ATIII and lysis before stasis. With Hbalc as dependent variable VIIIR:CoF is the only significant predictor variable in diabetics (Table 9).

Plasma prekallikrein, factor XII, antithrombin III, C1(-)-inhibitor and alpha 2-macroglobulin in critically ill patients with suspected disseminated intravascular coagulation (DIC)

In nine patients with suspected disseminated intravascular coagulation (DIC) and five controls, the following analyses were performed on admission and 7-29 hours later: Routine coagulation studies (fibrinogen, platelet count, fibrin(ogen) degradation products, ethanol gelation, reptilase time, Factor V) providing a semiquantitative DIC score, prekallikrein (PK), Factor XII, antithrombin III (AT-III), C1(-)-inhibitor and alpha 2-macroglobulin. Significant correlations were found: PK or AT III with the DIC-score, PK with AT-III and Factor XII, AT-III with Factor XII. The changes (expressed as a percentage of normal plasma) of PK and AT-III from the first to the second evaluation were nearly identical. The two patients with rapidly fatal irreversible shock showed the highest DIC score and a pronounced decrease of PK and AT-III, whereas in reversible shock stable or increasing PK and AT-III values were found. The other variables showed an overlap between reversible and irreversible shock. DIC in these shock patients, accompanied by a decrease in PK, probably was mediated via Factor XII activation. PK and AT-III might be of prognostic value in patients with (septic) shock.

[Criteria for hemostasis in kidney transplant patients. Comparison of patients undergoing immunosuppression with cyclosporin and azathioprine steroids]

Studies on one-year function conducted by the European Multicenter Trial showed that, after renal allograft transplantation, bleeding complications were only found in patients treated with cyclosporin as compared with those treated with azathioprin/steroids. To investigate a possible relationship between the bleeding tendency and the cyclosporin treatment, 18 parameters of hemostasis were studied in 11 patients, 6 of whom received cyclosporin A and the other 5 conventional treatment with azathioprin/steroids. Bleeding tendency could not be related to any specific coagulation parameter. Of interest is that clot retraction was significantly lower in the cyclosporin group (88 +/- 9% vs. 125 +/- 10%). Considering the fact that the skin bleeding time according to Ivy was normal in all patients, the clinical significance of the lower levels of the clot retraction appears to be minor. Discriminant analysis showed that these significantly lower clot retraction values could not be related to the lower platelet count levels in platelet rich plasma (205 000 +/- 85 000/mm3 vs. 280 000 +/- 67 000/mm3) but were associated with cyclosporin A treatment. All factor-VIII related activities were elevated in both groups. The main difference between the cyclosporin group and the conventionally treated group was significantly elevated levels of factor VIII procoagulant antigen (VIII: CAg) (cyclosporin A treated group: VIII: CAg 435 +/- 145%, conventionally treated group: VIII: CAg 215 +/- 99%). These results suggest hypercoagulability rather than bleeding tendency under cyclosporin treatment.

In vitro effects of the acylated streptokinase-plasminogen activator complex BRL 33 575 incubated with normal human plasma

Thrombolysis with acylated streptokinase-plasminogen complexes is aimed to achieve fibrinolysis without systemic fibrinogenolysis. The p-aminobenzoyl-streptokinase-(Lys)-plasminogen-complex (BRL 33 575) should be particularly useful due to its slow deacylation rate. Unexpectedly, repeated doses of 10 mg of BRL 33 575 (corresponding to 310'000 streptokinase equivalent units) induced systemic effects in patients though less than streptokinase alone. In vitro incubation of normal human plasma with BRL 33 575 at concentrations used in patients resulted in nearly complete consumption of alpha 2-antiplasmin and plasminogen and significant fibrinogenolysis within 3 hr. This demonstrates that - despite of slow deacylation of BRL 33 575 - the small amounts of activator generated are highly efficacious in activating plasma plasminogen under conditions in which no physiological clearance of the free activator takes place. Simulating the calculated activator release from BRL 33 575 by infusing equivalent amounts of streptokinase into plasma resulted in less pronounced effects. This is probably explained by anti-streptokinase antibodies which will neutralize the initially infused streptokinase but will be bound by BRL 33 575. Our in vitro experiments indicate that further clinical studies should be done with lower doses of BRL 33 575 or prolonged dosage intervals.

[A frequent problem in the laboratory control of heparinization: contamination of blood specimens with exogenous heparin]

If blood for monitoring of heparin therapy is collected through indwelling catheters it may be contaminated by exogenous heparin. A prospective study comparing thrombin times in plasma obtained by venipuncture and by collection through heparin perfused catheters showed that 26 out of 77 catheter samples were contaminated. In 16 of these 26 cases, overestimation of the heparin effect would have led to incorrect dosage recommendations. It is concluded that blood for laboratory monitoring of heparin treatment should be collected by venipuncture.

Assay of Factor XII clotting activity in heparinized plasma

Clotting tests based upon the activated partial thromboplastin time are disturbed by heparin. This brief communication shows that Factor XII clotting activity in plasma samples heparinized in vitro and in vivo can be measured accurately by means of an aPTT-test using congenitally deficient substrate plasma when the plasma dilution buffer contains hexadimethrine bromide (Polybrene), 15 mg/L. This method of neutralizing heparin obviates more complicated procedures such as heparin adsorption to anion exchange resins.

Dissociation of factor VIII procoagulant antigen VIII:CAg and factor VIII related antigen VIIIR:Ag by EDTA - influence of divalent cation on the binding of VIII:CAg and VIIIR:Ag

Assuming 1 U/ml in citrated plasma, the VIII:CAg concentration was found 1.66 U/ml in EDTA-plasma, 1.09 U/ml in heparinized plasma and 0.67 U/ml in serum. Addition of 10 mmol/l EDTA to citrated and heparinized plasmas increased VIII:CAg 1.5fold. There was no increase of VIII:CAg in serum. Gel filtration of plasmas on different anticoagulants showed an elution of VIII:CAg in the void volume Vo and in the later fractions. The VIII:CAg amount detected in the internal volume increased following the series heparin less than citrate less than EDTA. Serum VIII:CAg was eluted at 2.2 Vo. Presence of EDTA in the elution buffer or incubation of plasma with EDTA prior to chromatography caused a displacement of practically all VIII:CAg amount in the internal volume with a peak at 2.2-2.3 Vo. VIIIR:Ag was exclusively detected in the void volume. Removal of divalent cation by chelation likely exposes more antigenic determinants of VIII:CAg, which are otherwise masked by steric hindrance due to VIIIR:Ag in citrated and heparinized milieu. Moreover gel filtration of plasma in the presence of EDTA completely dissociates VIII:CAg from VIIIR:Ag. The VIII:CAg fragment, having an estimated molecular weight of 70,000, might also be present in serum.

Preparation of factor VIII-free plasma by immunoaffinity chromatography on insolubilized antibodies against factor VIII-related antigen

A method is designed to prepare factor VIII-free plasma in large amounts. It is obtained from normal human plasma by immunoaffinity chromatography on insolubilized antibodies against factor VIII-related antigen. Its use in the routine assay of VIII procoagulant activity is well established by testing various samples ranging from 0 to 7 U/ml.

Rabbit antibodies against the procoagulant activity (VIII:C) of human factor VIII. Some theoretical and practical considerations on the human factor VIII molecule using heterologous antibodies

The procoagulant activity VIII:C was separated from factor VIII antigen (VIIIR:Ag) by gel filtration in the presence of 0.25 mol/l calcium chloride. Antibodies (anti-VIII:C) were obtained by immunization of rabbits with VIII:C. The last step of the purification procedure of antibodies consists of an adsorption on VIIIR:Ag-Sepharose 2 BCL as immunoadsorbent to remove contaminating traces of antibodies against VIIIR:Ag. The anti-VIII:C titer remains unchanged during this adsorption (29 Bethesda units per mg). In solution, anti-VIII:C neutralizes factor VIII activity (in plasma, cryoprecipitate or in purified form) and the fragment VIII:C without reacting with VIIIR:Ag. Once immobilized on a solid matrix, i.e. 2% agarose, it loses over 95% of its inhibitory capacity. The immobilized anti-VIIIR:Ag binds stoichiometrically the antigen and the activity of plasma factor VIII. These results together suggest that factor VIII is composed of 2 different entities, but undissociated under physiological conditions. Immunophysical analyses as a function of pH and temperature of anti-VIII:C and its complex with factor VIII show properties similar to those of homologous antibodies. The antigen determinants of VIII:C (VIII:CAg) are destroyed at low pHs or high temperatures, and VIII:C can no more form a complex with anti-VIII:C. Purified anti-VIII:C is also used in a two-stage assay to detect VIII:CAg or cross-reacting material in some severe haemophiliacs.

[Factor VIII (coagulation activity VIII:C, antigen concentration VIIIR:Ag and von Willebrand factor) in patients with clinically expected intravascular coagulation]

Factor VIII procoagulant activity, antigen concentration and von Willebrand activity as ristocetin cofactor were determined several times in 10 patients with DIC. These is a significant negative correlation between the DIC-score and the VIII:C/von Willebrand activity ratio.

Reactivity of a hereditary abnormal antithrombin III fraction in the inhibition of thrombin and factor Xa

Two different AT-III fractions were purified from the plasma of a patient with recurrent superficial thrombophlebitis. The abnormal AT-III fraction (A-AT) was compared to the normal AT-III fraction (N-AT) in the inhibition of thrombin and factor Xa. Without heparin, both inactivate proteases in a similar manner and at the same rate. However, at low heparin concentration the thrombin inhibition proceeds more slowly with A-AT than with N-AT. At high heparin concentration the difference between A-AT and N-AT becomes very small. The inhibition of factor Xa follows a similar pattern. It is suggested that the heparin binding site of A-AT differs from that of N-AT resulting in a decreased heparin cofactor activity.

[Dissociation of human factor VIII and recombination of the fragments VIII-C and VIII-AG]

Human factor VIII has been dissociated into fragment VIII-C and fragment VIII-AG in the presence of calcium chloride (0.25 M). After removing the calcium, recombination of the molecule is obtained. Fragment VIII-C can be activated by thrombin in a similar manner to the coagulant activity of whole factor VIII. This activation is calcium-dependent. In rabbits immunized against purified F VIII, VIII-C and VIII-AG specific antisera against these three entities were obtained.