bluuebunny/crossref_metadata_2025_split huggingface dataset:
Circulating Platelets Show Increased Activation in Patients with Acute Cerebral Ischemia
Authors: Tschoepe Diethelm , Kessler Christof , Zeller Joern 
Published: March 2018

SummaryPlatelet activation plays a central role in acute arterial stenosis as has been shown in coronary heart disease. Likewise it can be assumed to be of importance in the evolution of acute cerebral ischemia (ACI), particularly in patients with large vessel disease. Flow cytometric detection of platelet adhesion molecules as a marker of platelet activation in a group of patients with ACI and different etiologies has not been evaluated. In 72 patients with ACI and 72 controls, the exposure of activation-dependent adhesion molecules was determined using flow cytometry after immunostaining with monoclonal antibodies against CD 62, CD 63 and thrombospondin. The extent of platelet activation differed as a function of the etiology of ACI: platelets from patients with atherosclerosis of brain-supplying arteries expressed significantly more activation markers than did controls, whereas patients with cardioembolic stroke did not. By analyzing platelet adhesion molecules it is possible to describe platelet activation profiles in patients with acute cerebral ischemia. This diagnostic procedure will be useful for monitoring individualized anti-platelet therapy and may enable distinguishing different subgroups of stroke patients.
Genetic Effects for Plasma Factor VII Levels Independent of and in Common with Triglycerides
Authors: Pedersen Nancy , Egberg Nils , Faire Ulf , Hong Yuling 
Published: March 2018

Summary
Background. Coagulation factor VII has been demonstrated as a potential risk factor for cardiovascular disease. Both genes and non-genetic factors are related to plasma levels of factor VII. However, the extent to which genetic effects influence variability in plasma factor VII levels is unknown. Further, increased levels of plasma factor VII are associated with serum triglycerides, yet the reason for this association is not fully understood. Methods and Results. Quantitative genetic analyses were applied to evaluate the relative importance of genetic and different environmental influences on plasma factor VII levels and to test the significance of genetic and environmental factors in common to factor VII and triglycerides in 215 pairs of middle-aged and elderly twins, of whom 104 were reared apart and 120 were women. Genetic influences were found to account for 57% of the individual differences in plasma factor VII levels, whereas shared-rearing and residual-familial environmental factors were not significant. Furthermore, a significant genetic correlation of 0.38 was found between factor VII and triglycerides, but the environmental correlation between these two measures was not significant. Genetic factors in common to factor VII and triglycerides explain about 7% of the total variance for factor VII. Conclusion. The present study suggests that there are substantial genetic influences on plasma factor VII levels. Furthermore, genetic effects explain the phenotypic association between factor VII and triglycerides.
Vitamin K Deficiency Bleeding (VKDB) in Infancy
Authors: von Kries Rüdiger , Cornelissen Marlies , McNinch Andrew , Andrew Maureen , Sutor Anton 
Published: March 2018

Summary
Terminology. Replace the term “Hemorrhagic Disease of the Newborn” (HDN) by “Vitamin K Deficiency Bleeding” (VKDB), as neonatal bleeding is often not due to VK-deficiency and VKDB may occur after the 4-week neonatal period. Definition. VKDB is bleeding due to inadequate activity of VK-dependent coagulation factors (II, VII, IX, X), correctable by VK replacement. Diagnosis. In a bleeding infant a prolonged PT together with a normal fibrinogen level and platelet count is almost diagnostic of VKDB; rapid correction of the PT and/or cessation of bleeding after VK administration are confirmative. Warning signs. The incidence of intracranial VKDB can be reduced by early recognition of the signs of predisposing conditions (prolonged jaundice, failure to thrive) and by prompt investigation of “warning bleeds”. Classification. VKDB can be classified by age of onset into early (<24 h), classical (days 1-7) and late (>1 week <6 months), and by etiology into idiopathic and secondary. In secondary VKDB, in addition to breast feeding, other predisposing factors are apparent, such as poor in-take or absorption of VK. VK-Prophylaxis: Benefits. Oral and intramuscular VK (one dose of 1 mg) protect equally well against classical VKDB but intramuscular VK is more effective in preventing late VKDB. The efficacy of oral prophylaxis is increased with a triple rather than single dose and by using doses of 2 mg vitamin K rather than 1 mg. Protection from oral doses repeated daily or weekly may be as high as from i.m. VK. VK-Prophylaxis: Risks. VK is involved in carboxylation of both the coagulation proteins and a variety of other proteins. Because of potential risks associated with extremely high levels of VK and the possibility of injection injury, intramuscular VK has been questioned as the routine prophylaxis of choice. Protection against bleeding should be achievable with lower peak VK levels by using repeated (daily or weekly) small oral doses rather than by using one i.m. dose. Breast feeding mothers taking coumarins. Breast feeding should not be denied. Supervision by pediatrician is prudent. Weekly oral supplement of 1 mg VK to the infant and occasional monitoring of PT are advisable. Conclusion. VKDB as defined is a rare but serious bleeding disorder (high incidence of intracranial bleeding) which can be prevented by either one i.m. or multiple oral VK doses.
Factor XIII Val34Leu Is a Genetic Factor Involved in the Aetiology of Venous Thrombosis
Authors: Reitsma P. H. , Lourenço D. , Maffei F. H. , Morelli V. , Tavella M. H. , Araújo A. G. , Piccinato C. E. , Zago M. A. , Franco R F. 
Published: March 2018

SummaryA mutation in the factor XIII gene (FXIII Val34Leu) gene was recently reported to confer protection against myocardial infarction, but its relationship with venous thrombosis is unknown. In addition, a mutation in the 5’-untranslated region of the FXII gene (46 C→T) was identified which is associated with low plasma levels of the protein. Its prevalence in patients with venous thrombosis is also unknown. We investigated the frequency of the FXIII Val34Leu and FXII 46 C→T mutations in 189 patients with deep venous thrombosis and in 187 age-, gender- and race-matched controls. FXIII Val34Leu was detected in 38.6% of the patients and in 41.2% of the controls. Interestingly, homozygosity for the FXIII mutation was found in 1.6% of the patients and in 9.6% of the controls, yielding an odds ratio (OR) for venous thrombosis of 0.16 (95% CI: 0.05-0.5). The OR for hetero-zygotes was 1.1 (95% CI: 0.7-1.7). The FXII 46 C→T mutation was detected in 46.0% of the patients and in 48.6% of the controls. The OR for heterozygotes was 0.9 (95% CI: 0.6-1.4) and for homozygotes the OR was 0.8 (95% CI: 0.3-1.9). Our data indicate that the FXII 46 C→T mutation is unlikely to be a major risk factor for venous thrombotic disease. In contrast, the homozygous state for FXIII Val34Leu is a strong protective factor against venous thrombosis, which emerges as a novel genetic factor involved in the aetiology of thrombophilia.
The Relationship of Mutations in the MTHFR, Prothrombin, and PAI-1 Genes to Plasma Levels of Homocysteine, Prothrombin, and PAI-1 in Children and Adults
Authors: Balasa Vinod , Glueck Charles , Stroop Davis , Becker Ann , Pillow Ann , Wang Ping , Gruppo Ralph 
Published: March 2018

SummaryStudies in adults have demonstrated that the genetic mutations C677T methylenetetrahydrofolate reductase (MTHFR), prothrombin 20210A, and the 4G polymorphism of the plasminogen activator inhibitor-1 (PAI-1) gene are associated with elevated plasma levels of homocysteine, prothrombin and PAI-1, respectively and with an increased risk of thrombosis. No similar data is available in children. Therefore, we assessed the relationship of plasma levels of homocysteine, prothrombin and PAI-1 with their respective mutations in 197 normal children, compared to 40 adults. By stepwise multiple regression, homocysteine was positively associated with age, PAI-1 activity was negatively associated with age, while PAI-1 antigen and prothrombin levels were associated with gender, being higher in girls than boys. When the genotypes were added to the regression model as additional explanatory variables, the MTHFR genotype accounted for 2.9% of the variance of homocysteine (p = 0.024), and the PAI-1 gene accounted for 2.7% of the variance of PAI-1 antigen levels (p = 0.023). Of children homozygous for the MTHFR mutation, 35% had homocysteine levels ≥ the age-specific 95th percentile, compared to 2% hetero-zygotes and 5% wild type normals (p = 0.0001). The mean homocysteine level was higher in children homozygous for the MTHFR gene (8.4 μmol/l) than in heterozygotes (5.5 μmol/l), p <0.05. Of children homozygous for the 4G polymorphism of the PAI-1 gene, 19% had PAI-1 activity levels ≥ the age-specific 95th percentile, compared to 2% of heterozygotes and 3% of wild type normals (p = 0.003). Studies of the incidence of the MTHFR, prothrombin, and PAI-1 4G/5G genotypes in children with thrombosis, when compared to these healthy normals, will provide evidence as to which of these genes are associated with thrombophilia.This work was carried out following an institutional research committee approved protocol with signed informed consent.
Effects of Statins in Thrombosis and Aortic Lesion Development in a Dyslipemic Rabbit Model
Authors: Alfon J. , Pueyo Palazon C. , Royo T. , Badimon L. 
Published: March 2018

SummaryHMG-CoA reductase inhibitors (statins) are effective in primary and secondary prevention of coronary heart disease. The mechanism of action is mainly attributed to their plasma cholesterol lowering activity, although additional effects have been suggested. Our objective was to study whether atorvastatin and simvastatin exhibited an inhibitory effect on platelet deposition onto a triggering damaged vessel wall in addition to an antiatherosclerotic effect in the dyslipemic rabbit model. Statins were administered at identical doses of 2.5 mg/kg/day with a hyperlipidemic diet during 10 weeks. Both drugs similarly lowered total cholesterol and, moderately, triglycerides. Mural platelet deposition on damaged vessel wall placed in an ex-vivo flow perfusion system was reduced in atorvastatin treated animals (39.7 ± 6.2 × 106 PLT/cm2) vs. controls (94.8 ± 15.9 × 106 PLT/cm2, p <0.02). Simvastatin reduced aortic fatty streak surface coverage (31,7 ± 5.3%) vs. controls (47.9 ± 4.1%, p <0.005) and intimal thickening in thoracic aorta (0.15 ± 0.05 intima to total area ratio in simvastatin treated animals vs. 0.36 ± 0.03 in control animals, p <0.05). Atherosclerotic fatty streak coverage correlated positively with total cholesterol, tryglicerides and LDL-cholesterol levels in all groups. HMG-CoA reductase inhibitors similarly lowered plasma lipids but exhibited significantly different effects in the modulation of atherosclerotic development and platelet response at the tested dose. Therefore, the effect of statins on the progression and manifestation of cardiovascular disease might be also mediated by regulating platelet response to vessel injury.
The Prothrombin 20210A Allele and Its Association with Myocardial Infarction
Authors: Daly M. E. , Steeds R. P. , Channer K. S. , Samani N. J. , Hampton K. K. , Croft S. A. 
Published: March 2018

SummaryThe relationship between the prothrombin (PT) 20210A allele and arterial disease is controversial. We conducted a case-control study to assess its contribution to risk of myocardial infarction (MI). Five hundred and thirty-nine acute MI patients and 498 control subjects aged <75 years were studied. Two percent of cases carried the PT20210A allele compared to 2.8% of controls. The odds ratio for MI was 0.72 (95% CI 0.32-1.60) indicating that the PT20210A allele confers no increased risk for MI. Subgroup analysis showed no association between the PT20210A allele and either premature MI or MI in females. We conclude the PT20210A allele is not a risk factor for MI and suggest that discrepancies in studies relating the PT20210A allele to MI may be due to difficulties in estimating its low allelic frequency in the general population and thus random differences in the observed frequencies in the control populations studied.
Free and Total Platelet Glycoprotein IIb/IIIa Measurement in Whole Blood by Quantitative Flow Cytometry during and after Infusion of c7E3 Fab in Patients Undergoing PTCA
Authors: Metz Damien , Nazeyrollas Pierre , Nguyen Philippe , Simon Gérard , Daliphard Sylvie , Droullé Chantal , Elaerts Jacques , Potron Gérard , Hézard Nathalie 
Published: March 2018

SummaryA quantitative flow cytometry assay was used to evaluate the ex vivo kinetics of c7E3 Fab platelet effect in 16 patients undergoing PTCA treated with abciximab and compared with aggregometry assay. Immunolabeling of platelets was directly assessed on whole blood, using in parallel two monoclonal antibodies (Mabs) raised against GPIIIa, Mab1, the binding of which is inhibited by c7E3 Fab, and Mab2, the binding of which is not affected by c7E3 Fab. We found a severe and sustained inhibition of both GPIIb/IIIa receptors and platelet functions. The inter-individual variation in response to abciximab was low. A significant transient increase at H24 and H48 in the binding of Mab2 was found as an unexpected result, and confirmed in vitro. Results demonstrate that flow cytometry is a reliable method in agreement with aggregation. In addition, our results show that it is a standardized tool and a time-saving technique.
Lupus Anticoagulant Testing in Europe: An Analysis of Results from the First European Concerted Action on Thrombophilia (ECAT) Survey Using Plasmas Spiked with Monoclonal Antibodies against Human β2-Glycoprotein I
Authors: Meijer P. , Vermylen J. , Arnout J. 
Published: March 2018

SummaryLupus anticoagulants (LA) are immunoglobulins directed to either prothrombin or Beta-2-glycoprotein I (β2GPI) bound to phospholipids. Most patients with LA have both β2GPI- and prothrombin-dependent antibodies. Several recent reports have shown that LA is more strongly associated with thrombosis than anticardiolipin antibodies (aCL). Therefore, an accurate detection of LA is of utmost importance in patients suspected of an antiphospholipid syndrome. We recently raised a series of murine monoclonal antibodies against human Beta-2-glycoprotein I (β2GPI) with LA activity similar to affinity purified human β2GPI-dependent LAs. A normal plasma pool, and the same pool spiked with LA positive anti-β2GPI antibodies at two potency levels, were used as materials in an external quality assessment scheme organised by the European Concerted Action on Thrombosis (ECAT). Fifty nine laboratories participating in this trial were asked to test for the presence of a LA in the 3 samples submitted. The majority (82%) of the participants found the high potency LA sample to be positive. Only 37% of the laboratories considered the weak potency LA sample to be positive. The submission of a normal sample, a weakly positive sample and a clearly positive sample enabled us to compare the relative LA responsiveness of the different screening assays used. Clotting time ratios varied from 0.81 to 3.28 for sample B and from 0.66 to 5.32 for sample D. In general, the highest clotting time ratios were found with the dilute prothrombin time (dPT), the dilute Russell Viper Venom time (dRVVT) and the Kaolin Clotting time. The most frequently used screening tests were the aPTT and the dRVVT. With the various assay systems, LA responsiveness varied largely according to the reagents used. For the β2GPI-dependent LA used in this study, PTT LA clearly showed the highest responsiveness among the aPTT reagents and Innovin among the dPT reagents. The present study also shows that many laboratories still rely on poorly responsive screening assays for their LA tests. Other laboratories rely on sensitive and more specific integrated test systems based on a sensitive screening assay with a low phospholipid content and a confirmatory test employing high phospholipid concentrations. The most used integrated system was dRVVT based. However, also here the LA responsiveness was largely reagent dependent.In conclusion, many laboratories still rely on poorly responsive screening assays by which weakly positive LA samples are misdiagnosed. LA positive anti-β2GPI moabs have a potential for the unlimited production of LA control specimens, that may help hemostasis laboratories choose more LA responsive assay systems and to assess intra-laboratory precision of their LA testing.
Precise Carrier Diagnosis in Families with Haemophilia A: Use of Conformation Sensitive Gel Electrophoresis for Mutation Screening and Polymorphism Analysis
Authors: Williams I. J. , Abuzenadah A. , Winship P. R. , Preston F. E. , Dolan G. , Wright J. , Peake I. R. , Goodeve A. C. 
Published: March 2018

SummaryCausative mutations in the factor VIII gene of seven unrelated patients with severe haemophilia A were identified using the mutation screening procedure conformation sensitive gel electrophoresis (1) and characterised by direct sequencing. Female family members of all patients had requested either carrier status determination or prenatal diagnosis. However, lack of the factor VIII gene inversion, a prior family history or informative polymorphisms prevented diagnosis in these families. Identification of a mutation in each family enabled female carrier status to be determined in all cases. Six mutations were previously unreported. One Afro-Caribbean patient had two sequence changes; A670 2G and A6769G. The latter, resulting in Met2238Val and previously reported as a FVIII mutation, was shown to be polymorphic with a 42% heterozygosity rate in an Afro-Caribbean population. Conformation sensitive gel electrophoresis was found to be technically simple and efficient at locating previously unknown FVIII gene mutations.
Superficial Vein Thrombosis: Incidence in Association with Pregnancy and Prevalence of Thrombophilic Defects
Authors: Ramsay J. E. , Tait R. C. , Walker I. D. , McCall F. , Conkie J. A. , Carty M. J. , Greer I. A. , McColl M. D. 
Published: March 2018

SummarySuperficial venous thrombotic (SVT) events are a feature of thrombophilic abnormalities, particularly those involving the protein C pathway. We have determined the incidence of SVT associated with pregnancy and the early postpartum period in a retrospective study involving 72 000 deliveries. Fourty-nine cases occurring in 47 individuals were recorded, with an overall incidence of 0.68/1000 deliveries (95% CI 0.48-0.88). None had a previous history of deep vein thrombosis or pulmonary embolism. Most events occurred in the early post-partum period (0.54/1000 deliveries). Twenty-four/fourty-seven were screened for established thrombophilic abnormalities, with only 1 abnormality detected (FVLeiden heterozygote). Thrombophilia may play a minor role in the aetiology of SVT associated with pregnancy, although a larger study is required to confirm this.
The Contribution of Anti-prothrombin-antibodies to Lupus Anticoagulant Activity
Authors: Oort Erica van , Derksen Ronald , de Groot Philip , Horbach Daniëlle 
Published: March 2018

SummaryThe presence of lupus anticoagulant (LAC) is strongly correlated with a history of thrombosis in patients with SLE. LAC activity can be caused by anti-prothrombin (FII)- and/or anti-β2glycoprotein I (β2GPI)-antibodies.In the present study, the contribution of anti-FII-antibodies to LAC activity was measured in 28 LAC positive plasmas. Plasmas were incubated with prothrombin or BSA, immobilized on CNBr-activated Sepharose, to absorb all anti-FII-antibodies. In 4 out of the 28 plasmas LAC activity was completely dependent on anti-FII-antibodies. In 7 out of the 28 plasmas, anti-FII-antibodies did not contribute to LAC activity. These anti-FII-antibodies can be regarded as non-functional antibodies. In the majority (17/28) of the samples, LAC activity within a single plasma was caused by a combination of antibodies with different specificities. Both dRVVT and KCT showed comparable sensitivity for the detection of functional anti-FII-antibodies.In conclusion, in most samples LAC activity is not caused by anti-FII-antibodies alone but by a combination of different types of antibodies. The presence of LAC activity and anti-FII-antibodies in one plasma does not automatically implicate that these antibodies are responsible for the LAC activity.
Effects of Skin Mast Cells on Bleeding Time and Coagulation Activation at the Site of Platelet Plug Formation
Authors: Kauhanen Petteri , Kovanen Petri , Reunala Timo , Lassila Riitta 
Published: March 2018

SummaryWe studied the effects of stimulated skin mast cells on bleeding time and thrombin generation which was measured using prothrombin fragment F 1+2 (F 1+2) and thrombin-antithrombin-III-complex (TAT). In 10 patients with urticaria pigmentosa (chronic cutaneous mast cell accumulation) the mean bleeding time was significantly prolonged in wounds made on urticaria pigmentosa lesions vs. normal skin (460 ± 34 vs. 342 ± 27 s, p = 0.005). In 10 atopic subjects skin incisions were made on prick-tested sites 30, 60, 120 and 240 min after administration of an allergen (acute mast cell stimulation), histamine or vehicle. The mean bleeding time was significantly prolonged at all time points, being maximal at 120 min (60% prolonged) in wounds made on allergen-stimulated skin areas (p <0.01) compared with histamine or vehicle sites. Administration of allergen or histamine lowered the TAT concentration in the bleeding-time blood. Furthermore, TAT and F 1+2 levels in the bleeding-time blood were lower at 60, 120 and 240 min after allergen or histamine application in comparison with samples collected at 30 min. We conclude that skin mast cells can regulate primary hemostasis by prolonging bleeding time and by inhibiting thrombin generation.
Superficial Vein Thrombosis of Lower Limbs: Influence of Factor V Leiden, Factor II G20210A and Overweight
Authors: Wutschert Robert , Heinzmann Monica , Perneger Thomas , Reber Guido , Bounameaux Henri , Moerloose Philippe de 
Published: March 2018

SummarySuperficial vein thrombosis (SVT) has been reported in patients with thrombophilia. In the present unmatched case-control study, the two most common thrombophilic abnormalities (factor V Leiden and factor II G20210A) were searched for in 112 consecutive patients with SVT of lower limbs and in 180 healthy donors. FV Leiden was present in 16/112 (14.3%) SVT patients and 11/180 (6.1%) controls (odds ratio 2.51, 95% CI 1.04-6.24) and FII G20210A in 4/112 (3.6%) patients and 2/180 (1.1%) controls (OR 3.28, 95% CI 0.46-36.84). In addition, body mass index (BMI) ≥28 kg/m2 was also associated with SVT (OR 2.81, 95% CI 1.60-5.00). After adjustement for BMI ≥28 kg/m2, the association between FV Leiden and SVT remained strong though no longer statistically significant. Among patients with SVT, the presence of FV Leiden was independently associated with the absence of varicose veins (OR 4.62, 95% CI 1.25-18.0) and with a BMI ≥28 kg/m2 (OR 3.74, 95% CI 1.05-15.1). In conclusion, both FV Leiden and overweight seem to predispose to SVT, a finding that should be confirmed in larger studies.