Degradation Products In Plasma Research Articles

The Mortality Risk and Pulmonary Fibrosis Investigated by Time-Resolved Fluorescence Spectroscopy from Plasma in COVID-19 Patients.

A method of rapidly pointing out the risk of developing persistent pulmonary fibrosis from a sample of blood is extraordinarily needed for diagnosis, prediction of death, and post-infection prognosis assessment. Collagen scar formation has been found to play an important role in the lung remodeling following SARS-CoV-2 infection. For this reason, the concentration of collagen degradation products in plasma may reflect the process of lung remodeling and determine the extent of fibrosis. According to our previously published results of an in vitro study, an increase in the concentration of type III collagen degradation products in plasma resulted in a decrease in the fluorescence lifetime of plasma at a wavelength of 450 nm. The aim of this study was to use time-resolved fluorescence spectroscopy to assess pulmonary fibrosis, and to find out if the lifetime of plasma fluorescence is shortened in patients with COVID-19. The presented study is thus far the only one to explore the fluorescence lifetime of plasma in patients with COVID-19 and pulmonary fibrosis. The time-resolved spectrometer Life Spec II with the sub-nanosecond pulsed 360 nm EPLED® diode was used in order to measure the fluorescence lifetime of plasma. The survival analysis showed that COVID-19 mortality was associated with a decreased mean fluorescence lifetime of plasma. The AUC of mean fluorescence lifetime in predicting death was 0.853 (95% CI 0.735–0.972, p < 0.001) with a cut-off value of 7 ns, and with 62% sensitivity and 100% specificity. We observed a significant decrease in the mean fluorescence lifetime in COVID-19 non-survivors (p < 0.001), in bacterial pneumonia patients without COVID-19 (p < 0.001), and in patients diagnosed with idiopathic pulmonary fibrosis (p < 0.001), relative to healthy subjects. Furthermore, these results suggest that the development of pulmonary fibrosis may be a real and serious problem in former COVID-19 patients in the future. A reduction in the mean fluorescence lifetime of plasma was observed in many patients 6 months after discharge. On the basis of these data, it can be concluded that a decrease in the mean fluorescence lifetime of plasma at 450 nm may be a risk factor for mortality, and probably also for pulmonary fibrosis in hospitalized COVID-19 patients.

Visual and Biochemical Evidence of Glycocalyx Disruption in Human Dengue Infection, and Association With Plasma Leakage Severity.

Background: Dengue is the most common arboviral infection globally; a minority of patients develop shock due to profound plasma leak through a disrupted endothelial barrier. Understanding of the pathophysiology underlying plasma leak is incomplete, but emerging evidence indicates a key role for degradation of the endothelial glycocalyx.Methods: We conducted an observational study in Vietnam to evaluate the sublingual microcirculation using sidestream darkfield imaging in (1) outpatients with confirmed dengue (2) patients hospitalized with dengue and (3) outpatients with other febrile illness (OFI). We estimated the glycocalyx degradation by measuring the perfused boundary region (PBR hf) and an overall microvascular health score (MVHS) with the software application GlycoCheckTM at enrolment, 48 h later and hospital discharge/defervescence. We measured plasma syndecan1 and endocan at the same time-points. We compared PBR hf, MVHS, syndecan1 and endocan, between (1) outpatients with confirmed dengue vs. OFI and (2) patients with dengue subdivided by clinical severity of plasma leak.Results: We included 75 patients with dengue (41 outpatients, 15 inpatients, 19 in intensive care) and 12 outpatients with OFI. Images from 45 patients were analyzed using GlycoCheckTM. There was no significant difference in PBR hf or MVHS between outpatients with dengue and OFI. Median plasma syndecan1 was not significantly different in outpatients with dengue vs. OFI, while median plasma endocan was significantly lower among patients with dengue vs. OFI during the critical phase. In patients with dengue, PBR hf was higher in patients with Grade 2 vs. Grade 0 plasma leakage during the critical phase (PBR hf 1.96 vs. 1.36 μm for Grade 2 vs. Grade 0 plasma leakage on days 4–6, respectively, p < 0.001). Median levels of plasma syndecan1 and endocan were higher in Grade 2 vs. Grade 0 plasma leakage, especially during the critical phase (Syndecan1 2,613.8 vs. 125.9 ng/ml for Grade 2 vs. Grade 0 plasma leakage on days 4–6, respectively, p < 0.001, and endocan 3.21 vs. 0.16 ng/ml for Grade 2 vs. Grade 0 plasma leakage on days 4–6, respectively).Conclusions: We present the first human in vivo evidence of glycocalyx disruption in dengue, with worse visual glycocalyx damage and higher plasma degradation products associated with more severe plasma leak.

Factor V Leiden mutation enhances fibrin formation and dissolution in vivo in a human endotoxemia model

Disseminated intravascular coagulation in sepsis is associated with microvascular thrombosis and organ dysfunction. It was expected that prothrombotic disposition such as factor V Leiden (FVL) mutation would worsen clinical outcome. Astonishingly, clinical trial and animal experimental data indicate that FVL can be associated with improved survival. This study investigated the effect of FVL on the response to endotoxin of the coagulation and fibrinolytic system in humans. Fourteen healthy male subjects without FVL and 15 healthy males with heterozygous FVL received an intravenous bolus dose of endotoxin, 2 ng/kg of body weight. Blood samples were drawn before and 1, 2, 4, 6, and 24 hours after administration of the endotoxin. Injection of endotoxin led to a more pronounced increase in soluble fibrin in patients with FVL than in controls. Patients with FVL displayed a more sustained increase in plasmin-plasmin inhibitor complex after 4, 6, and 24 hours. Patients with FVL mutation also displayed higher levels of D-dimer and fibrinogen-fibrin degradation products in plasma after 24 hours. Patients with FVL generate higher levels of soluble fibrin, which may serve as cofactor in tissue plasminogen activator-induced plasminogen activation, leading to a more sustained activation of fibrinolysis with production of more fibrinogen- and fibrin-degradation products.

Endothelial glycocalyx as potential diagnostic and therapeutic target in cardiovascular disease

The endothelial glycocalyx has emerged as a potential orchestrator of vascular homeostasis. Under physiological conditions, the glycocalyx is an important contributor to the regulation of vascular permeability for macromolecules as well for the adhesion of circulating cells. In line, the potential role of the glycocalyx in maintaining the antiatherogenic properties of the vessel wall may have important clinical implications. In the present review, we provide an overview of recent developments and a glance at the future of establishing endothelial glycocalyx as a crucial player in cardiovascular protection. Novel methods to estimate glycocalyx dimensions in vivo (using Orthogonal Polarization Spectral imaging or Sideview Darkfield imaging) as well as progressive insight into the enzymes involved in glycocalyx synthesis will be crucial in the assessment of this structure as a potential surrogate marker or therapeutic target for cardiovascular risk. The validation of these 'imaging' techniques and the integration with glycocalyx degradation products in plasma will allow us to test the value of the endothelial glycocalyx in estimating cardiovascular risk. The endothelial glycocalyx, protecting the vascular wall against atherogenic influents, could be used for cardiovascular risk stratification. For this purpose, new methods to estimate glycocalyx dimension are promising.

Quantification methods of folpet degradation products in plasma with HPLC-UV/DAD: Application to an in vivo toxicokinetic study in rats

Solid-phase extractions followed by HPLC-UV/DAD methods were developed for occupational biological monitoring or forensic investigations of the fungicide folpet using its degradation products, phthalimide and phthalamic acid as plasma biomarkers. These methods show good linearity ( r > 0.9955), precision (CV < 15%) and accuracy (bias < 14.8%). The lower limits of quantification for phthalimide and phthalamic acid were 10 and 20 ng/ml and the absolute recoveries were higher than 86% and 68%, respectively. Applying these methods, a plasma toxicokinetic study of folpet in rats after intratracheal administration of Folpan 80WG ® showed that inhalation of folpet could be a route of exposure with an important systemic absorption.

Neurotoxic disorders of organophosphorus compounds and their managements.

Organophosphorus compounds have been used as pesticides and as chemical warfare nerve agents. The mechanism of toxicity of organophosphorus compounds is the inhibition of acetylcholinesterase, which results in accumulation of acetylcholine and the continued stimulation of acetylcholine receptors. Therefore, they are also called anticholinesterase agents. Organophosphorus pesticides have largely been used worldwide, and poisoning by these agents, particularly in developing countries, is a serious health problem. Organophosphorus nerve agents were used by Iraqi army against Iranian combatants and even civilian population in 1983 - 1988. They were also used for chemical terrorism in Japan in 1994 - 1995. Their use is still a constant threat to the population. Therefore, medical and health professionals should be aware and learn more about the toxicology and proper management of organophosphorus poisoning. Determination of acetylcholinesterase and butyrylcholinesterase activity in blood remains a mainstay for the fast initial screening of organophosphorus compounds but lacks sensitivity and specificity. Quantitative analysis of organophosphorus compounds and their degradation products in plasma and urine by mass spectrometric methods may prove exposure but is expensive and is limited to specialized laboratories. However, history of exposure to organophosphorous compounds and clinical manifestations of a cholinergic syndrome are sufficient for management of the affected patients. The standard management of poisoning with organophosphorous compounds consists of decontamination, and injection of atropine sulfate with an oxime. Recent advances on treatment of organophosphorus pesticides poisoning revealed that blood alkalinization with sodium bicarbonate and also magnesium sulfate as adjunctive therapies are promising. Patients who receive prompt proper treatment usually recover from acute toxicity but may suffer from neurologic complications.

The Harmonization of Quantitative Test Results of Different D-Dimer Methods

Nowadays D-dimer testing is frequently applied in the diagnosis of venous thromboembolism. However, the test results of different quantitative D-dimer tests can differ significantly. The background of this variability, which is mainly caused by the variety of fibrin degradation products in plasma, the specificity of D-dimer assays, and the calibrators used in the test, is summarized here. Because D-dimer is not a single entity in plasma but a mixture of heterogeneous fibrin degradation products, method standardization is in principle impossible. Efforts undertaken in the past to standardize D-dimer methods are summarized. All these projects failed and it was concluded that only harmonization of D-dimer test results seems to be feasible. The results of a large field study on which a new approach to the harmonization of quantitative D-dimer methods will be based is summarized in this article. This approach seems to be an adequate solution for overcoming the practical problem of variation of test outcome in different D-dimer assays.

Diagnostic aspects of organophosphate poisoning

Organophosphate (OP)-type chemical warfare agents (nerve agents) present a constant threat to the population. Sensitive and specific methods for the detection and verification of exposure to nerve agents are required for diagnosis, therapeutic monitoring, health surveillance and forensic purposes. Determination of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity in blood remains a mainstay for the fast initial screening but lacks sensitivity and specificity. Quantitative analysis of nerve agents and their degradation products in plasma and urine by mass spectrometric methods may prove exposure but is limited to hours or days after the incident due to the short residence time of the analytes. Investigation of protein adducts extends the time interval between exposure and sampling and may be suitable to detect low-level exposure. Definitive prove of exposure requires a spectrum of different methods, expensive and sophisticated equipment and will be limited to specialized laboratories.

PLATSAK, a Potent Antithrombotic and Fibrinolytic protein, Inhibits Arterial and Venous Thrombosis in a Baboon Model

Antiplatelet-antithrombin-staphylokinase (PLATSAK) is a chimeric protein that was recombinantly produced in Escherichia coli cells. The protein was designed to target haemostasis at three different levels. It consists of staphylokinase for activation of fibrinolyis, the Arg-Gly-Asp sequence for the prevention of platelet aggregation, and an antithrombotic peptide for the inhibition of thrombin. The in vivo activity of PLATSAK was evaluated by assessing its effect on platelet deposition in a baboon model of arterial and venous thrombosis. Dacron vascular graft segments and expansion chambers, inserted as extensions into permanent femoral arteriovenous shunts, were used to simulate arterial and venous thrombosis, respectively. PLATSAK (3.68 mg/kg) was administered as a bolus 10 minutes before placement of the thrombogenic devices. Platelet deposition onto the graft surface and in the expansion chamber was imaged in real time with a scintillation camera as the deposition of 111In-labeled platelets. After 2 hours, platelet deposition in the graft segments and expansion chambers was inhibited by 50% and 85%, respectively, when compared to control studies. The activated partial thromboplastin time was lengthened to greater than 120 seconds. Interestingly, the level of fibrinogen degradation products in plasma did not increase after administration of PLATSAK. These results demonstrate that PLATSAK effectively inhibited platelet deposition in both arterial- and venous-type thrombosis in an animal model.

Fibrin and fibrinogen degradation products in plasma of patients with colorectal adenocarcinoma.

The aim of the present study was to correlate the preoperative plasma levels of TDP in patients with colorectal cancer to tumor stage, metastasis, and postoperative thromboembolic complications. Ninety-one patients with colorectal cancer, 20 patients with colorectal adenoma, and 71 patients without neoplastic lesions in the colon or rectum were included in this prospective study. Before surgery, total fibrin and fibrinogen degradation products (TDP) were measured in plasma of all patients with a specific enzyme-linked immunosorbent assay test. Phlebography was performed postoperatively in 82 of 91 patients with colorectal cancer. Median TDP in plasma of patients with colorectal cancer (805 (range, 339-5,024) ng fibrinogen equivalents (ngFE)) was significantly higher than TDP in patients with colorectal adenoma (591 (range, 417-1386) ngFE/ml) and TDP in patients without neoplastic lesions in the colon (632.8 (range, 180-2622) ngFE/ml; P < or = 0.003). In patients with colorectal cancer and liver metastasis, TDP in plasma (1085.5 (range, 468-5024) ngFE/ml) was significantly higher than in patients with localized tumor growth (753 (range, (339-2,780) ngFE/ml; P < or = 0.02). Twenty of 82 patients (24 percent) with cancer developed thromboembolic complications. TDP was preoperatively significantly higher in this group of patients (1,101 (range, 468-2,167) ngFE/ml) compared with patients without thromboembolic complications (753 (range, 339-5024) ngFE/ml; P < or = 0.04). Preoperative plasma levels of TDP were elevated in patients with colorectal cancer, especially in patients with liver metastasis and in patients developing postoperative deep venous thrombosis.

71. A specific test for polymorphonuclear leukocyte-mediated fibrinogenolysis in plasma

In response to inflammatory mediators, polymorphonuclear leukocytes (PMN) are activated and release potent serine proteases, i.e. elastase, cathepsin G and proteinase 3. The aim of this study was to develop an assay to determine PMNmediated fibrinogenolysis in plasma, as a biochemical marker for activated PMN in vivo. On the basis of a special monoclonal antibody, generated against a neo-antigenic site in elastase degraded fibrinogen (EOF), we developed a highly specific plasma test for PMN-generated fibrin(ogen) derivatives. Intact fibrin(ogen) did not cross react in the assay, nor did plasmin-generated fibrin(ogen) derivatives. With this assay we showed, amongst others, that smoking did not affect the values of EDF-like degradation products in plasma of normal healthy volunteers (overall 8.2±1.6 ng/ml; n= 18) and that EDF-values are increased in patients with an ccl-proteinase inhibitor deficiency (18.6±5.3 ng/ml; n=12) and with sepsis (365.7±198.4 ng/ml; n=16). The assay was also applied to assess PMN-mediated fibrinogenolysis in synovial tissue extracts of patients with rheumatoid arthritis; these contained very high levels of EDF (98.2±59.3 ng/ml; n=15), in contrast to synovial tissue extracts of patients with osteoarthritis (6.3±2.7 ng/ml; n=12). The assay may be useful to identify patients with activated PMN, and to monitor drug-efficacy during therapy. This study was partly supported by grants from the Dutch Asthma Foundation (NAF 91.39 and 93.73) and the Praeventiefonds (002819180). © Pearson Professional Ltd 1996.

Fibrin turnover in plasma and peritoneal dialysis effluent of capd patients with and without peritonitis

Fibrin deposition in the peritoneal cavity of patients with chronic renal failure on continuous ambulatory peritoneal dialysis (CAPD) may result in adhesions and peritoneal fibrosis. We used a new fibrin specific monoclonal antibody for demonstrating different turnover of fibrin monomer and fibrin degradation products in plasma compared to dialysis effluent of CAPD patients. In all patients we measured higher levels of fibrin monomer (FM) in dialysate than in plasma, even higher in plasma and effluent of patients with peritonitis. Western blot showed only high molecular bands (310–340 KD) in plasma. In the dialysis effluent we found seven bands up to 100 KD indicating the presence of fibrin degradation products (FbDP).

Pharmacokinetics of degradation products of fibrin and fibrinogen during alteplase therapy of acute myocardial infarction

Pharmacokinetics of fibrin degradation products (FbDP), D-dimers, fibrinogen degradation products (FgDP) and total degradation products (TDP) in plasma were investigated using ELISA methods in 12 patients undergoing therapy with alteplase (100 mg/3 h) for acute myocardial infarction. Peak concentrations of all degradation products occurred significantly later (1.6–2.5 h) than peak alteplase levels (2 min). Peak D-dimer concentrations (mean 2.6 μg/ml) were significantly lower than those of FbDP (7.1 μg/ml) or FgDP (7.8 μg/ml). However, the half-life of D-dimers (mean 13.3 h) was more than 4.5-fold longer than that of FbDP (2.9 h) or FgDP (2.8 h) (p<0.001). Consequently, areas under the plasma concentration-time curve (AUC) of D-dimers were comparable with those of FbDP or FgDP The ratios AUC(FbDP)/AUC(FgDP) and AUC(D-dimers)/AUC(FgDP) are proposed as new indices of fibrin specificity. Their values in this study (geometric mean, 95% CI) were 1.15 (0.60–2.20) and 1.30 (0.52–3.24) respectively. It is concluded that cross-linking may prolong the half-life of fibrin degradation products, and that complete time profiles of fibrin- and fibrinogen degradation products in plasma, rather than single point measurements, are essential for reliable quantification of fibrin specificity.

Elevated Concentrations of Cross-Linked Fibrin Degradation Products in Plasma: An Early Marker of Gram-Negative Bacteremia

Because coagulant and fibrinolytic activity are increased by endotoxin, we hypothesized that concentrations of cross-linked fibrin degradation products, sensitive markers of plasmin activity, would be increased in patients with Gram-negative bacteremia. Cross-linked fibrin degradation products were measured with an enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody specific for cross-linked fibrin degradation products, and with a novel, semiquantitative hemagglutination assay based on the same antibody coupled to FAB' fragments from a monoclonal antibody against a universal red blood cell antigen. Blood samples were obtained from 100 consecutive emergency department patients evaluated for sepsis. Blood cultures were positive in 21 percent of the patients, 75 percent (12/21) with Gram-negative organisms. Elevations of cross-linked fibrin degradation products (normal < 200 ng/ml) were measured by ELISA in all patients (12/12) with Gram-negative bacteremia. The hemagglutination assay was positive in ten of these. Detectable increases in fibrinolytic activity occurred in all patients with Gram-negative bacteremia, even in the absence of clinical signs or laboratory evidence of sepsis or disseminated intravascular coagulation. The ELISA and hemagglutination assay had negative predictive values for Gram-negative bacteremia of 100 percent and 96 percent, respectively. Elevation of cross-linked fibrin degradation products consistent with increased fibrinolytic activity occurs in all patients with Gram-negative bacteremia. Accordingly, the lack of elevation may be clinically useful in identifying patients less likely to have Gram-negative bacteremia.

GPR-phoresis, a novel approach to determining fibrin monomer and other macromolecular derivatives of fibrinogen and fibrin in blood

An electrophoretic method for determining (i) cross-linked fibrin-complexes, (ii) fibrin-monomer, (iii) fibrinogen-dimers, (iv) normal fibrinogen and (v) degradation products in plasma, has been devised. The technique is based on differences in their migration characteristics in the presence and absence of Gly-Pro-Arg (GPR), a specific inhibitor of fibrin aggregation. In buffer containing 2.5 mM GPR, fibrin monomer and fibrinogen co-migrate anodally but, unlike fibrinogen which does not depend on GPR for solubility, the fibrin monomers precipitate when they traverse a boundary between buffer containing and buffer lacking GPR. By limiting the GPR to a 2 cm zone of buffer under the conditions employed, the precipitation of fibrin monomer occurs in a sharp band 4 mm anodally to the sample application point. Cross-linked fibrin complexes have slower mobility than fibrin monomer and precipitate in a broad band behind the monomer, Dimeric fibrinogen, like fibrinogen itself but unlike the fibrin complexes, is not constrained to migration within the GPR boundary and passes through it, but behind the band for normal fibrinogen due to sieving by the gel. Fibrinogen and all but low molecular weight degradation products can be specifically precipitated within electrophoregrams by heat denaturation at 47°C. After washing unrelated protein away, the fibrin(ogen) derivatives can be measured by staining with Coomassic® blue, Since the method does not depend on immunoprobing for specific staining, it provides an inexpensive and rapid means for differential assessment of the prevalence of the fibrinogen derivatives in disease states and in models of disease, regardless of animal species.

GPR-phoresis, a novel approach to determining fibrin monomer and other macromolecular derivatives of fibrinogen and fibrin in blood

An electrophoretic method for determining (i) cross-linked fibrin-complexes, (ii) fibrin-monomer, (iii) fibrinogen-dimers, (iv) normal fibrinogen and (v) degradation products in plasma, has been devised. The technique is based on differences in their migration characteristics in the presence and absence of Gly-Pro-Arg (GPR), a specific inhibitor of fibrin aggregation. In buffer containing 2.5 mM GPR, fibrin monomer and fibrinogen co-migrate anodally, but, unlike fibrinogen which does not depend on GPR for solubility, the fibrin monomers precipitate when they traverse a boundary between buffer containing and buffer lacking GPR. By limiting the GPR to a 2 cm zone of buffer under the conditions employed, the precipitation of fibrin monomer occurs in a sharp band 4 mm anodally to the sample application point. Cross-linked fibrin complexes have slower mobility than fibrin monomer and precipitate in a broad band behind the monomer. Dimeric fibrinogen, like fibrinogen itself but unlike the fibrin complexes, is not constrained to migration within the GPR boundary and passes through it, but behind the band for normal fibrinogen due to sieving by the gel. Fibrinogen and all but low molecular weight degradation products can be specifically precipitated within electrophoregrams by heat denaturation at 47 degrees C. After washing unrelated protein away, the fibrin(ogen) derivatives can be measured by staining with Coomassie blue. Since the method does not depend on immunoprobing for specific staining, it provides an inexpensive and rapid means for differential assessment of the prevalence of the fibrinogen derivatives in disease states and in models of disease, regardless of animal species.

Increased tissue-type plasminogen activator activity in orthotopic but not heterotopic liver transplantation: the role of the anhepatic period.

The major cause of the increased tissue-type plasminogen activator activity during orthotopic liver transplantation is still unclear. Both the lack of hepatic clearance of tissue-type plasminogen activator in the anhepatic period and increased endothelial release from the graft on reperfusion have been proposed as the major causes. Heterotopic liver transplantation avoids the resection of the host liver and is a useful model to help differentiate between these two possibilities. In this study the fibrinolytic system was evaluated in 10 orthotopic liver transplantations, 18 heterotopic liver transplantations and a control group of 10 partial hepatic resections. A marked increment in tissue-type plasminogen activator activity, from 0.2 to 5.2 IU/ml (p less than 0.02), was observed during the anhepatic period of orthotopic liver transplantation, which rapidly normalized after reperfusion. In contrast, tissue-type plasminogen activator activity levels remained normal in heterotopic liver transplantation and partial hepatic resections. In orthotopic liver transplantation and in heterotopic liver transplantation no increase occurred in tissue-type plasminogen activator activity after reperfusion. The first venous hepatic outflow after reperfusion did not contain elevated tissue-type plasminogen activator activity levels. Plasma degradation products of fibrin and fibrinogen increased during the anhepatic period of orthotopic liver transplantation (from 2.60 to 8.80 micrograms/ml [p less than 0.008] and from 0.40 to 1.60 micrograms/ml [p less than 0.04], respectively) and remained elevated thereafter. In heterotopic liver transplantation and partial hepatic resections these levels remained low. In conclusion, the lack of hepatic clearance during the anhepatic period is probably the most important factor in the evolution of increased tissue-type plasminogen activator activity during orthotopic liver transplantation.

Specific identification of fibrin(ogen) degradation products in plasma and serum using blotting and peroxidase labeled antiserum

We describe a method for identifying fibrinogen and fibrin split products using electrophoresis on agarose gel with sodium dodecyl sulfate (SDS) followed by blotting in nitrocellulose paper. Detection of these derivatives after blotting is accomplished with peroxidase-conjugated rather than by isotopically labeled antibodies. This technique can detect diverse fibrinogen derivatives produced in vivo or in vitro by the combined action of thrombin, plasmin, and factor XIII. This methodology is applicable to plasma, serum, and other body fluids including urine and ascitic fluid. This sensitive and specific assay, distinguishing the products of cross-linked fibrin from those of fibrinogen and detecting fibrin polymers in plasma, can be achieved without the use of radioactivity.

Thrombin-antithrombin III-complex & fibrin degradation products in plasma: Surgery and postoperative deep venous thrombosis

Thrombin-antithrombin-III complexes (TAT) & D-dimer in plasma, and fibrin(ogen) degradation products (FDP) in serum, were measured in 48 patients subjected to total hip arthroplasty. Blood samples were collected on days -1, 0, 1, 3, 7 and 10. Five patients developed post-operative deep vein thrombosis (DVT) diagnosed by venography. A characteristic pattern of TAT and D-dimer secondary to surgery was demonstrated. A poor correlation was found between ELISA-and latex-D-dimer concentrations after the operation. Patients with DVT had significantly higher TAT-levels preoperatively, and on day 0, 7 and 10. The concentration of FDP was significantly elevated in patients with DVT on day 7 and that of ELISA D-dimer on days 0 & 10. None of the assays are clinically valuable for purposes of postoperative screening for DVT. The preoperative plasma TAT concentration may represent a valuable predictive marker of postoperative DVT.

SYSTEMIC EFFECTS OF TISSUE PLASMINOGEN ACTIVATOR-ASSOCIATED FIBRINOLYSIS AND ITS RELATION TO THROMBIN GENERATION IN ORTHOTOPIC LIVER TRANSPLANTATION

Orthotopic liver transplantation is frequently associated with hyperfibrinolysis, the origin and clinical relevance of which is largely unknown. In 20 orthotopic liver transplantations, we studied the occurrence and systemic effects of hyperfibrinolysis. Severe fibrinolysis was defined to be present when the euglobulin-clot lysis time and the whole-blood-clot lysis time, as measured by thrombelastography, were shorter than 60 and 90 min, respectively, at some time during the operation. Based on these criteria, 7 patients had minimal fibrinolysis (group I), and 13 patients had severe fibrinolysis (group II). In group II a gradual increase of tissue-type plasminogen activator (t-PA) activity was seen during the anhepatic stage, followed by an "explosive" increase immediately after graft reperfusion (P = 0.0004, compared with group I), and a reduction of plasminogen activator inhibitor (PAI) activity. Plasma degradation products of fibrinogen and fibrin increased parallel to t-PA activity, and levels were significantly higher at 45 min after graft reperfusion in group II compared with group I (P less than 0.04). Thrombin-antithrombin III complexes showed an identical steady increase in both groups, indicating that increased t-PA activity was not related to thrombin formation. A combination of increased endothelial release and reduced hepatic clearance may have caused the increased t-PA activity. The t-PA-associated destruction of fibrinogen and fibrin after graft reperfusion is consistent with the clinical signs of severe oozing often seen in this period. These observations may have important clinical implications for the treatment of bleeding in patients undergoing orthotopic liver transplantation.