Lipoprotein(a), other lipoproteins and hemostatic profiles in patients with ischemic stroke: the relation to cardiogenic embolism.

Lipoprotein and hemostatic profiles including coagulation inhibitors were determined in 136 patients with acute ischemic stroke. Based on clinical examination, cerebral computed tomography, Doppler ultrasonography of precerebral arteries and transthoracic echocardiography, the strokes were classified as cardioembolic (n = 38), non-cardioembolic (n = 92), and mixed cardioembolic/hypertensive (n = 6). Patients with cardioembolic stroke were older than patients with non-cardioembolic stroke. Lipoprotein(a) was higher in the cardioembolic than in the non-cardioembolic group. Lipoprotein(a) was not significantly correlated to the other lipid levels and may represent an independent lipid risk factor. The non-cardioembolic group had higher levels of total cholesterol, triglycerides, total cholesterol/high-density lipoprotein cholesterol ratio, low-density lipoprotein cholesterol, apolipoprotein A1, and apolipoprotein B. The cardioembolic group had higher concentrations of fibrinogen and D-dimer, and lower levels of antithrombin, protein C, protein S and heparin cofactor 2 than the non-cardioembolic group. The differences in the hemostatic profile are consistent with thrombosis due to activated coagulation being more involved in the pathogenesis of cardioembolic than of non-cardioembolic stroke. Lipoprotein(a) seems to be more associated with coagulation markers of thrombosis than with atherosclerosis, whereas the other lipids mainly seem to be risk factors for atherosclerosis.

Evidence of a protein C-like anticoagulant system in bony fish.

Evidence is presented, confirming the presence of an anticoagulant system in the plasma of Atlantic salmon (Salmo salar L) and rainbow trout (Oncorhynchus mykiss Walbaum) (Order: Teleostei, Family: Salmonidae) that bears striking similarities with the protein C anticoagulant system in mammals; its vitamin K-dependence was documented through a warfarin feeding trial. A potent activator of this system is the protein C activator from the venom of the Central American Moccasin, Agkistrodon bilineatus. When activated, the system splits the tripeptide substrate glu-pro-arg-pNa, which is the substrate preferred for the in vitro assay of human protein C. It also prolongates the plasma activated partial thromboplastin time, indicating that the system is of clinical relevance. A temperature dependence of the plasma protein C-like activity was evident, the mean activity being 5- to 10-fold higher, but also more variable, in both species in summer and early fall, than it was in winter. There was also a species difference, with rainbow trout having the higher levels. In man, subnormal values of protein C implies an increased risk of thrombosis. Whether this applies to fish is not known. It is, however, a fact that microvascular thromboses are prevalent in farmed Atlantic salmon in winter, whereas thrombotic disease is not a problem in rainbow trout; in the present study plasma protein C-like activity was 30% (of a human reference plasma) in salmon at 4 degrees C compared to a level of 60% in rainbow trout. A complicating factor for the assay of protein C-like activity in salmonid plasma, is the poor stability of the inhibitory system upon storage. Consequently, assays have to be done with freshly prepared citrated plasma.

Some functional properties of teleost antithrombin.

Antithrombin from bony fish (Teleostei), represented by an ancient salmonid, Atlantic salmon (Salmo salar L.), and a more evolved species from the same family, rainbow trout (Oncorhynchus mykiss Walbaum), functions in vitro as does its human counterpart: it inactivates thrombin almost instantaneously in the presence of heparin and only slowly when heparin is absent. The inhibitory activity of salmonid antithrombin towards the homologous thrombin did not differ noticeably from its inactivating capacity in heterologous (teleost) systems, and enzyme-inhibitor reactions between reagents from fish and man proceeded just as efficiently. In all enzyme-inhibitor reactions with salmonid thrombin the inactivation by salmonid antithrombin or diluted fish plasma was maximal at pH 7.8-8.4. The inactivation was clearly dependent on heparin in all systems and maximal at concentrations between 1.5 and 6 U/ml. What particularly distinguishes the salmonid thrombin-antithrombin interaction from the human one is that the former has to function over a wide range of temperatures. And the thrombin inactivating capacity of purified antithrombin and diluted plasma in the presence of heparin was indeed present at temperatures down to 3 degrees C, a capacity that human antithrombin also has retained. Even more interesting was that the teleost enzyme-inhibitor reaction was nearly independent of temperature under the conditions studied.

An automated C4b binding protein assay compared with an electroimmunoassay in a clinical material.

We have evaluated an automated, simplified, turbidimetric method for the measurement of the C4b binding protein (C4bBP). A comparison with a manually performed electroimmunoassay in plasma samples referred for coagulation analysis (n = 80) revealed a correlation coefficient of 0.88. Lipaemic plasma is not suitable for analysis, whereas moderately haemolytic or icteric plasma may be used with the present method. In young and middle-aged patients (n = 33) investigated 3 or more months after an episode with thrombosis of unknown reason, the mean C4bBP concentration was not significantly different from the mean found in healthy controls (n = 38). This result is in accordance with the hypothesis that C4bBP is an acute phase reactant. The results indicate that the turbidimetric assay may replace the electroimmunoassay in clinical work.

Free protein S deficiency in patients with Crohn's disease.

Multifocal intestinal infarctions, due to thrombosis in small vessels, might be a pathogenetic mechanism for Crohn's disease (CD). Deficiency of free protein S may contribute to the development of such thrombotic occlusions. In the present study free protein S was measured in 54 patients with CD. In 31 patients (57.4%) the plasma concentrations of free protein S were below the lower normal range. The mean value of free protein S in CD patients was 72.2%, as compared with 97.5% in healthy subjects (p < 0.01). The concentrations of C4b-binding protein and protein C were similar in the two groups. Free protein S levels were not correlated to disease activity, previous surgery or complications, extraintestinal manifestations, or current medical therapy. The impairment of the protein S/protein C/thrombomodulin system found in patients with CD favours coagulation and might be of importance for both the development of CD and its thromboembolic complications.

[Familial protein S deficiency]. / Familiaer protein S-mangel.

Protein S deficiency is an autosomal dominant inherited disease. The authors describe a family in which 27 of the 52 members had a deficiency of S protein. Eight family members have suffered from thromboembolic disease.

[Protein S deficiency, acute phase reaction and thrombosis]. / Protein S-mangel, akuttfasereaksjon og trombose.

Protein S deficiency increases risk of thrombosis. At present, we have information on 63 Norwegian individuals with hereditary protein S deficiency belonging to 25 different families. 42 of the individuals have experienced at least one thromboembolic episode, and seven a cerebral infarction before the age of 70 years. The amount of free protein S in plasma is dependent on variation of the acute phase protein C4b-binding protein (C4bBP). Acute phase response with increased C4bBP induces free protein S deficiency, and increases risk of thrombosis. In patients with protein S deficiency, warfarin may reduce free protein S to critically low levels, and thus explain why, in some patients, recurrent thrombosis occurs during warfarin treatment. In this situation, warfarin should be replaced by heparin.

Free protein S deficiency in patients with chronic inflammatory bowel disease.

Free protein S, protein C, and C4b-binding protein (C4b-BP) were measured in randomly selected outpatients: 22 with Crohn's disease (CD) and 16 with ulcerative colitis (UC). Active disease was recorded in 10 patients with CD and 4 with UC. Fourteen patients (63.6%) with CD and 4 (25%) with UC had free protein S values below the normal range, with mean values of 62% and 78% of that found in healthy control subjects (p < 0.01). The C4b-BP level was 127% in patients with CD as compared with 89% in both healthy subjects and UC patients (p < 0.01). The protein C levels were similar in the three groups. The present results add to the factors already known favouring thromboembolic complications in inflammatory bowel disease and which might play a major role both for the pathogenesis and for the increased tendency to venous thromboembolism in these diseases.

Coagulation inhibition and activation in pancreatic cancer. Changes during progress of disease.

BACKGROUND: To elucidate the disturbed hemostatic balance in patients with pancreatic cancer, the levels of plasma coagulation inhibition and coagulation activation were determined. METHODS: Twenty-one patients with adenocarcinoma of the pancreas were followed from time of diagnosis until death, using plasma analyses of coagulation inhibitors and a molecular marker of coagulation activation (thrombin-antithrombin complex, TAT). RESULTS: TAT was increased significantly at the time of diagnosis of pancreatic cancer compared with age-adjusted healthy control subjects (mean, 6.2 +/- 4.6 micrograms/l [standard deviation] versus 2.0 +/- 0.7 micrograms/l). It increased with disease progression (mean in the terminal phase, 14.1 micrograms/l; P < 0.05). Plasma levels of tissue factor pathway inhibitor (TFPI) also were increased significantly at the time of diagnosis compared with the control group (mean, 176 +/- 80% versus 127 +/- 29%; P < 0.05). The TFPI decreased to normal levels (121 +/- 40%) after surgical removal of the pancreatic tumor (n = 4) or relief of the cholestasis using a bypass procedure (n = 6). The TFPI levels increased significantly as the malignant disease progressed (from 1-3 months postoperatively to the terminal phase of disease; mean, 114 +/- 52% versus 154 +/- 60%). There was a significant positive correlation between TFPI levels and bilirubin levels; the correlation coefficient at diagnosis was 0.70 (P < 0.001). The levels of the coagulation inhibitors antithrombin, heparin cofactor II, protein C, and free protein S decreased significantly with disease progression compared with the normal values found at diagnosis. CONCLUSIONS: The mechanism for TFPI increase in cancer is not known. It may be related to the preoperative cholestasis seen in this study, but the increased degree of coagulation activation also may contribute.

Recurrent venous thrombosis during warfarin treatment related to acquired protein S deficiency.

Failure of warfarin to prevent new thrombotic processes was observed in three patients with very low free protein S concentrations and high C4b-binding protein (C4bBP) concentrations, and in one patient with hereditary protein S deficiency. We suggest that an increase in C4bBP reduces the free Protein S level, and warfarin treatment causes an additional decrease of free protein S. The four patients presented indicate that such reductions are of clinical importance. Heparin seems preferable as an anticoagulant in this situation, as warfarin given alone is ineffective, or may even be harmful. In a group of pancreatic cancer patients with advanced disease, subnormal mean free protein S was found, whereas mean total protein S concentration, and mean C4bBP concentrations were significantly higher (p less than 0.01) than in healthy controls. These findings indicate that an increase in C4bBP may induce free protein S deficiency contributing to the increased thrombotic tendency in this group of patients. The correlation between free protein S and C4bBP was 0.11, (n.s.), between total protein S and C4bBP 0.73 (p less than 0.0001).

Protein C in patients with alcoholic cirrhosis and other liver diseases.

The coagulation inhibitor protein C was measured in 151 patients with various liver diseases. The protein C level was significantly decreased in patients with alcoholic cirrhosis (n = 73) compared to patients with steatosis (n = 24) (40 +/- 2%) vs. 88 +/- 4%, mean S.E., p less than 0.001). It was also decreased in cases of acute liver damage (n = 8) and in patients with non-alcoholic cirrhosis (n = 15) (35 +/- 7% and 36 +/- 4%, respectively). A significant correlation was found between protein C and Normotest, antithrombin, heparin cofactor II, (r = 0.83, r = 0.82, r = 0.81, respectively, p less than 0.001). There was also a significant correlation between protein C and serum concentrations of albumin (r = 0.61, p less than 0.001), but a negative association to bilirubin (r = -0.56). No significant association was found between protein C and aspartate aminotransferase, alaline aminotransferase, and gamma-glutamyltranspeptidase. In conclusion, protein C is low in advanced liver diseases and gives the same amount and type of information as Normotest, antithrombin and heparin cofactor II.

Chromogenic substrate assay of extrinsic pathway inhibitor (EPI): levels in the normal population and relation to cholesterol.

A two-stage chromogenic substrate assay was standardized to measure extrinsic pathway inhibitor (EPI) activity in plasma and serum samples. In the first stage, diluted plasma or serum (0-0.8%) was incubated with factor VIIa (25 pM), tissue thromboplastin (tissue factor, TF, 1% v/v) with excess binding sites for factor VIIa, and factor Xa (0.8 nM). In the second stage, excess factor X and chromogenic substrate were added as substrate for residual TF/factor VIIa catalytic activity. Heating the samples at 56 degrees C for 15 min before assay removed greater than 95% of the factor VII amidolytic activity of the samples, defibrinated the plasma, and produced only slight reduction of EPI activity. The coefficient of variation for the same sample assayed on different days was 8.7-10.6% and the intra-assay coefficient of variation was 5.0%. Addition of anti-EPI immunoglobulin to normal plasma completely abolished the EPI activity of the sample. EPI activity was stable in plasma samples stored at -20 degrees C, but in serum, some samples lost greater than 50% activity after 3 months at -70 degrees C. Median EPI activity of umbilical cord blood was 45% (range 33-93%). In a cohort of healthy blood donors (n = 176) EPI activity was significantly correlated with age; the regression line was y = 68% + 0.60x (r = 0.39). The approximated standard deviation for the regression line was 17.9% and the age-adjusted reference limits were determined. Equal levels were seen in males and females.(ABSTRACT TRUNCATED AT 250 WORDS)

[Protein C deficiency and the P pill]. / Protein C-mangel og p-pille.

A 18-year old woman was hospitalized because of vena cava inferior thrombosis, renal vein thrombosis and pulmonary embolism due to inherited protein C deficiency and three months of contraceptive treatment with oestrogen hormones. Protein deficiency was detected in 12 other members of the family. The father had had a pulmonary embolism 12 years earlier, and two other members may have died of thromboembolism.

PIP: An 18 year old woman was hospitalized because of a vena cava inferior thrombosis, renal vein thrombosis, and pulmonary embolism due to an inherited protein C deficiency. She received 3 months of contraceptive treatment with estrogens. Protein deficiency was detected in 12 other members of her family; her father had a pulmonary embolism 12 years earlier and 2 other members of the family may have died of thromboembolism. (author's modified)

The long-term safety of antihyperlipidaemic drugs.

In the hope of reducing the cardiovascular complications of severe hyperlipidaemia a series of lipid-lowering drugs have, in the course of the years, been developed and brought into use. The question of their efficacy/safety balance in long-term prophylaxis has remained an important one, repeatedly prompted by studies suggesting either that the benefit is limited or that there are risks in such prolonged treatment which cannot be detected during premarketing investigations. A long period may elapse before a clear picture emerges of the extent to which such drugs influence the atherosclerotic process or measures such as total mortality, carcinogenesis, mental function or fertility, or if these drugs give rise to interactions. Repeated efforts will be needed to maintain a consensus on the state of knowledge and the information which should be provided to the public and medical media.

Monitoring therapy with LMW heparin: a comparison of three chromogenic substrate assays and the Heptest clotting assay.

Three LMW heparins (LMWH), one unfractionated heparin (UH), and international standards of LMWH and UH were compared in three chromogenic substrate (CS) assays and the 'Heptest' clotting assay. With a two-stage CS assay, linear standard curves were obtained in the 0.1-1.0 U/ml range, nearly coinciding for all preparations. With the one-stage CS assays, standard curves were curvilinear and similar for UH and the LMWH groups. In the Heptest assay, standard curves were linear for UH but not for LMWH. Mean recovery of LMWH, added to patients' plasma samples was 70-98% for the four assays. Variation between individual recoveries was much greater with Heptest (coefficient of variation (CV) 35-44%) than with one-stage CS assays (CV 14-21%) or two-stage CS assays (CV 7-8%). For monitoring LMW heparin therapy, CS assays seem preferable to Heptest. The two-stage CS assay had superior accuracy, but the one-stage CS assays were easier to perform.

Serum levels of vitamin D metabolites in the elderly.

The serum concentrations of 25-dihydroxyvitamin D, 1,25-dihydroxyvitamin D, 24,25-dihydroxyvitamin D, vitamin D-binding protein, PTH and calcitonin were measured in three groups of elderly Norwegian subjects (age 70-96 years): active elderly living at home, warded geriatric patients not supplemented with vitamin D, and warded geriatric patients supplemented with a daily dose of 400 IU vitamin D2. The results were compared with the concentrations of vitamin D metabolites found in a group of young and middle-aged adults (age 22-59 years). Decreased serum concentrations of 25-dihydroxyvitamin D3 were found in all groups of elderly compared with younger adults. Active elderly living at home had higher concentrations of 25-dihydroxyvitamin D3 than geriatric ward patients. Supplementation of geriatric ward patients with 400 IU vitamin D2 resulted in an increase in the median serum 25-dihydroxyvitamin D concentration by about 30 nmol/l. Decreased median concentration of 1,25-dihydroxyvitamin D was found in geriatric ward patients not supplemented with vitamin D, indicating that this group is at risk of vitamin D deficiency. The active elderly living at home and the warded geriatric patients receiving vitamin D supplementation had normal median concentrations of 1,25-dihydroxyvitamin D, indicating that nephrogenous synthesis of 1,25-dihydroxyvitamin D is not generally impaired in the elderly, and that a moderate vitamin D supplementation may correct low 1,25-dihydroxyvitamin D levels, owing to vitamin D deficiency. However, the serum concentrations of 1,25-dihydroxyvitamin D showed great individual variations. No significant differences were observed for vitamin D-binding protein, 'free-1,25-dihydroxyvitamin D, or PTH between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Familial antithrombin deficiency]. / Familiaer antitrombinmangel.

When known causes of a disposition to thrombosis are discovered (e.g. antithrombin, protein C or protein S deficiency) it is important to investigate family members and inform individuals who are deficient in the factor in question. Knowledge about the cause of the thrombophilia will stimulate prophylactic efforts, and may be very important for diagnosis and treatment of the patient. A recently discovered new family with antithrombin deficiency is presented.

The inhibitor of F VIIa in plasma measured with a sensitive chromogenic substrate assay: comparison with antithrombin, protein C and heparin cofactor II in a clinical material.

The plasma inhibitor(s) of factor VIIa-tissue thromboplastin cooperates with factor Xa. This "Extrinsic Pathway Inhibitor" has been quantitated with a sensitive chromogenic substrate assay. Gel filtration of plasma separates 3 EPI peaks. Postoperatively, both EPI and the other coagulation inhibitors decrease. Unlike the other inhibitors, EPI is usually normal in severe liver cirrhosis. In disseminated intravascular coagulation, EPI levels vary considerably.