Gender Differences in Fibrin Polymerization and Lysability of Fibrin in Patients with Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia for both men and women. The embolic cardiovascular events represent serious complications of AF, and apparently women are affected more seriously than men. Little is known about prothrombotic factors and possible gender differences. The present study aimed to characterize fibrin polymerization, fibrinolysis, and fibrin fiber properties in men and in women with AF. MATERIALS AND METHODS: Forty-six female and 101 male patients with AF and without previous stroke were included. Polymerization kinetics, lysis of preformed clot, and fibrin fiber properties were determined by turbidimetric methods. RESULTS: Women were slightly older than men (P < .01), and the male group had a higher systolic blood pressure (P < .01) and a higher incidence of peripheral arterial disease (P < .01) than the female group. Compared with men, women had a higher Vmax during fibrin polymerization (P < .04) and a lower lysability of fibrin, when recombinant tissue plasminogen activator (rt-PA) was added during clot formation (P < .01), while external lysis (rt-PA added after clot formation), plasma fibrinolytic activity, d-dimer, and fibrin fiber properties did not differ between men and women. A significantly higher number of men received acetylsalicylic acid (ASA) compared with women (P < .004). Subgroup analyses on subjects not receiving ASA demonstrated that women still had higher Vmax (P < .04) and a lower rt-PA-induced fibrinolysis (P < .03). CONCLUSION: Women with AF have a higher velocity of lateral aggregation of fibrin fiber protofibrils and a lower lysis of fibrin clots than men.

Randomized controlled trial of cholecalciferol supplementation in chronic kidney disease patients with hypovitaminosis D.

BACKGROUND: Hypovitaminosis D is common in chronic kidney disease (CKD). Effects of 25-hydroxyvitamin D replenishment in CKD are not well described. METHODS: An 8-week randomized, placebo-controlled, double-blind parallel intervention study was conducted in haemodialysis (HD) and non-HD CKD patients. Treatment consisted of 40,000 IU of cholecalciferol orally per week. Plasma 25-hydroxyvitamin D (25-OHD), plasma 1,25-dihydroxyvitamin D (1,25-diOHD), plasma parathyroid hormone (PTH), serum phosphate, ionized serum calcium and serum fibroblast growth factor 23 (FGF-23) were analysed. We also investigated biomarkers related to cardiovascular disease (plasma D-dimer, plasma fibrinogen, plasma von Willebrand factor antigen and activity, plasma interleukin 6, plasma C-reactive protein, blood pressure, aortic augmentation index, aortic pulse wave velocity and 24-h urinary protein loss). Objective and subjective health variables were assessed (muscle function tests, visual analogue scores and Health Assessment Questionnaire). RESULTS: Fifty-two CKD patients with 25-OHD <50 nmol/L at screening were included. Cholecalciferol supplementation led to a significant increase to a median of 155 nmol/L 25-OHD (interquartile range 137-173 nmol/L) in treated patients (n = 25, P < 0.001). In non-HD patients, we saw a significant increase in 1,25-diOHD (n = 13, P < 0.01) and a lowering of PTH (n = 13, P < 0.001). This was not observed in HD patients. Cholecalciferol supplementation caused a significant increase in serum calcium and FGF-23. CONCLUSIONS: 25-OHD replenishment was effectively obtained with the employed cholecalciferol dosing. In non-HD patients, it had favourable effects on 1,25-diOHD and PTH. Vitamin D-supplemented patients must be monitored for hypercalcaemia. The present study could not identify significant pleiotropic effects of 25-OHD replenishment.

Multivariate analysis of the relation between diet and warfarin dose.

PURPOSE: The vitamin K antagonist (VKA) warfarin is effective for the prevention of thromboembolisms. Maintenance doses differ greatly among patients and are known to be primarily determined by genetic polymorphisms. The relative impact of dietary vitamin K intake is still a matter of debate. We hypothesize that a multivariate model is more suitable for exploring the relation between dietary intake of vitamin K and warfarin dose than conventional uni- or bivariate analyses. METHODS: In a cross-sectional study, we interviewed 244 patients in the maintenance phase of warfarin therapy and detected polymorphisms in the VKORC1 and CYP2C9 genes. Dietary vitamin K intake was estimated from food frequency questionnaires. RESULTS: A univariate correlation analysis and the regression coefficient from the multivariate model showed a small but significant negative relation between vitamin K intake and warfarin dose. A loading plot of the partial least squares regression model illustrated this counter-intuitive observation, which might be explained by the latent structure between variables. The variation in warfarin dose could be divided into two significant latent variables, the so-called components. In component one, pharmacogenetics explained 52% of dose variation. Component two described health-related behavior (diet, physical activity and body weight) and explained 8% of dose variation. Here, vitamin K intake positively correlated with warfarin dose. DISCUSSION: This study highlights the importance of choosing a statistical method that reflects the complexity of data for interpretation of results from observational studies. The multivariate model appears to be well suited to describe the complex relationship between vitamin K intake and VKA dose.

Co-Creation and Co-Production of Health Promoting Activities Addressing Older People-A Scoping Review.

The global population is aging and the promotion of health and well-being for this generation is essential. Co-creative and co-productive practices can be solutions to welfare challenges in local policies. Therefore, this scoping review aimed to understand the extent and type of evidence in relation to the co-creation and co-production of health-promoting activities addressing older people aged 60+ years and to examine the influence of co-creative and co-productive activities on health and well-being, including influential factors for co-creation and co-production. We searched for peer-reviewed and grey literature in ten scientific and five non-scientific databases. From the 2648 studies retrieved, 18 articles were included in this review. Then, an inductive thematic content analysis was applied to the analysis. Three categories related to co-creative and co-productive activities emerged: "Social and physical activities", "Development of age-friendly environments", and "Discussions of healthy and active aging". Facilitating factors for co-creation and co-production were related to the planning and structure of the process and recognition of participants' time and resources, while the recruitment of participants and their time and resources were the main barriers. Future studies should target co-creative and co-productive interventions to concrete areas and specific sub-groups and be aware of factors influencing a co-creative or co-productive relationship with older people.

Effects on markers of inflammation and endothelial cell function of three ad libitum diets differing in type and amount of fat and carbohydrate: a 6-month randomised study in obese individuals.

Diet is important for the prevention of CVD, and diets high in MUFA might be more cardioprotective than low-fat diets. We hypothesise that inflammation and endothelial cell function will be improved most favourably by a high-MUFA diet compared with a low-fat diet. This was tested in a parallel randomised intervention trial on overweight individuals (aged 28·2 (SD 4·6) years) assigned to a diet moderate in the amount of fat (35-45% of energy; >20% of fat as MUFA; MUFA diet, n 39), a low-fat (20-30% of energy) diet (LF diet, n 43) or a control diet (35 % of energy as fat, n 24) for 6 months after weight loss. Protein constituted 10-20 % of energy in all diets. Food was provided free of charge. Fasting blood samples were collected before and after the intervention and analysed for C-reactive protein (CRP), IL-6, intercellular adhesion molecule, von Willebrand factor (vWF) and tissue factor pathway inhibitor. vWF concentrations tended to fall on the LF diet (4·78 (SD 16·44) %; P = 0·07). Concentrations of IL-6 were reduced by the MUFA (0·37 (SD 0·74) pg/ml; P < 0·01) and LF (0·47 (SD 0·69) pg/ml; P < 0·001) diets, and CRP was reduced on all diets (MUFA: 0·48 (SD 1·93) mg/l (P < 0·01); LF: 1·46 (SD 2·89) mg/l (P < 0·001); control: 1·20 (SD 1·97) mg/l (P < 0·01)). No significant differences were observed between changes induced by the different diets. Our findings suggest that in overweight subjects after weight loss, the MUFA and LF diets have similar long-term effects on inflammation and endothelial cell function.

Plenty of pills: polypharmacy prevails in patients of a Danish anticoagulant clinic.

PURPOSE: Vitamin K antagonist (VKA) treatment can successfully prevent thromboembolic complications, but the modality has a narrow therapeutic window and numerous interactions with other pharmaceuticals. The aim of the study reported here was to describe the use of co-medications and the prevalence of polypharmacy among patients treated with VKA. METHODS: In a cross-sectional study, 250 consecutive patients (65% male, median age 68 years, most common indication for VKA treatment: atrial fibrillation) in the maintenance phase of VKA treatment were interviewed about their use of prescription medications, over-the-counter drugs and alternative medicines during the last 7 days. RESULTS: The interviewed patients used a median of five medications (range 1-13), including VKA. Approximately 50% of the patients also took alternative medicines. A wide range of conventional and alternative medicines were used, several of which harbour possible interactions with VKA. Polypharmacy was defined as the use of five or more medications, excluding alternative medicines. The group of polypharmacy patients included 53% of the study population. The use of amiodarone, age >50 years, the indication for VKA treatment being atrial fibrillation or mechanical heart valves and diabetes were independent predictors of polypharmacy. CONCLUSIONS: The results of this study highlight that polypharmacy is a common phenomenon among patients on anticoagulant medication, particularly among elderly patients or those suffering from cardiovascular disease or diabetes.

Simplified method for international normalized ratio (INR) derivation based on the prothrombin time/INR line: an international study.

BACKGROUND: The need to perform local International Sensitivity Index (ISI) calibrations and in particular the requirement for a manual method for prothrombin time (PT) determination, have proved to be obstacles to application of the WHO scheme for PT standardization. METHODS: We used international normalized ratio (INR) derived with a set of only 5 European Concerted Action on Anticoagulation (ECAA) lyophilized calibrant plasmas, certified manually by expert centers with reference thromboplastins, to determine a local PT/INR Line. We compared results of an independent set of validation plasmas with INRs from conventional ISI calibrations and with manually certified INRs. RESULTS: The mean certified INR of 5 lyophilized validation plasmas was 2.41 with human thromboplastin, 2.04 with bovine/combined, and 2.80 with rabbit. With 42 human reagents, the mean observed INR of the validation plasmas was 2.68 (11.2% deviation from certified INR). Deviation was reduced to 0.4% with both local ISI calibration and the PT/INR Line. Eight results based on bovine/combined thromboplastin gave an INR deviation of 4.9%, becoming 0.5% after ISI calibration and 2.4% with the PT/INR Line. Six results with rabbit reagents deviated from certified INR by 2.5%. After ISI calibration, deviation became 1.1%, and with the PT/INR Line, 0.7%. The PT/INR Line gave similar results with both linear and orthogonal regression analysis. The total proportion of validation plasmas giving INR within 10% deviation from certified values was 42.5% with uncorrected INR, which increased to 92.1% with local ISI calibration and 93.2% with the PT/INR Line. CONCLUSIONS: The PT/INR Line procedure with 5 ECAA calibrant plasmas successfully substitutes for local ISI calibrations in deriving reliable INRs.

Long-term effects on haemostatic variables of three ad libitum diets differing in type and amount of fat and carbohydrate: a 6-month randomised study in obese individuals.

Diet is important in the prevention of CVD, and it has been suggested that a diet high in MUFA is more cardioprotective than a low-fat diet. We hypothesised that the thrombotic risk profile is improved most favourably by a high-MUFA diet compared with a low-fat diet. This was tested in a parallel randomised intervention trial on overweight individuals (aged 28·2 (sd 4·6) years) randomly assigned to a diet providing a moderate amount of fat (35-45 % of energy; >20 % of fat as MUFA) (MUFA diet; n 39), to a low-fat (LF; 20-30 % of energy) diet (n 43), or to a control diet (35 % of energy as fat; n 24) for 6 months after a weight loss of about 10 %. Protein constituted 10-20 % of energy in all three diets. All foods were provided free of charge from a purpose-built supermarket. Fasting blood samples were collected before and after intervention and analysed for factor VII coagulant activity (FVII:c), fibrinogen, prothrombin fragment 1+2 (F1+2), D-dimer and plasminogen activator inhibitor (PAI). The fibrinogen concentration was significantly lowered by the LF diet, but not by the MUFA diet. Changes in fibrinogen differed significantly between diet groups. BMI and PAI concentration increased and D-dimer concentrations were reduced irrespective of the diets. No changes were observed for FVII:c and F1+2. Our findings suggest that in overweight subjects after weight loss the thrombotic risk profile is improved most favourably by the LF diet compared with the MUFA diet based on the reduction in fibrinogen concentrations.

A multicentre randomised assessment of the DAWN AC computer-assisted oral anticoagulant dosage program.

Computer-assisted oral anticoagulant dosage is being increasingly used to meet growing demands for oral anticoagulation. The DAWN AC is one of the most widely used computer-dosage programs. Evidence of its value and that of other computer programs has been based previously only on laboratory evidence of "time in target INR range" (TIR) not on clinical safety in practice. A five-year international randomised clinical study of computer assistance with the DAWN AC program compared with manual dosage in 2,631 patients has been performed at 13 centres with established expertise in oral anticoagulation mainly in the EU. Safety assessment have been based on the comparison of bleeding or thrombotic events with DAWN AC compared with manual dosage in a randomised study. Safety of the DAWN AC program has been demonstrated. Clinical events of bleeding and thrombosis were almost identical with the experienced manual dosage group. Therapeutic control improved with DAWN AC to 66.8% from 63.4% TIR. The program failed to provide a dosage recommendation on only 5.7% of occasions. At a group of experienced centres with a special interest in oral anticoagulation, the DAWN AC computer-dosage program proved as safe clinically as manual dosage by experienced medical staff. With DAWN AC, laboratory control was improved, the difference being highly significant. The results should reassure hospitals and community clinics that the DAWN AC program is safe and facilitate greater and longer provision of warfarin treatment where required.

A multicentre randomised clinical endpoint study of PARMA 5 computer-assisted oral anticoagulant dosage.

To meet growing demand for oral anticoagulation worldwide there has been increased dependence on computer-assistance in dosage although the safety and effectiveness of any of the individual computer-assisted dosage programs has not previously been established. This randomised multicentre clinical end-point study assessed a new version of the PARMA 5 program. It compared PARMA 5 safety and effectiveness with manual dosage by experienced medical staff at 19 centres with a known interest in oral anticoagulation. Target recruitment was 8000 patient-years, randomised to medical staff or PARMA-5 assisted dosage. Safety and effectiveness of the PARMA 5 program was compared with manual dosage. A total of 10,421 patients were recruited (15,369 patient-years) in the 5-year study. International normalised ratio (INR) tests numbered 167,791 with manual and 160,078 with PARMA 5 dosage. With parma 5 there was overall a non-significant reduction in clinical events but in the 2542 patients with deep vein thrombosis/pulmonary embolism, clinical events were significantly reduced (P = 0.005). Success in achieving 'time in target INR range' was also significantly greater with PARMA 5 compared with the dosage by experienced medical staff. This study demonstrated the safety and effectiveness of PARMA 5-assisted dosage.

Factor VII-activating protease in patients with acute deep venous thrombosis.

Factor VII-activating protease (FSAP) is involved in haemostasis and inflammation. FSAP cleaves single chain urokinase-type plasminogen activator (scu-PA). The 1601GA genotype of the 1601G/A polymorphism in the FSAP gene leads to the expression of a FSAP variant with reduced ability to activate scu-PA, without affecting the ability to activate coagulation Factor VII (FVII). Previous studies have investigated the association of the 1601GA genotype with incidence and progression of carotid stenosis and deep venous thrombosis (DVT). The present study is the first to evaluate the potential association between the FSAP phenotype and DVT. We studied the association between the 1601G/A polymorphism, FSAP activity, FSAP antigen, Factor VIIa (FVIIa), prothrombin fragment 1+2 (F1+2), and C-reactive protein (CRP) in plasmas of 170 patients suspected for DVT. FSAP genotypes were equally distributed in patients with (n=64) and without DVT (n=106), (P=0.94). The 1601GA genotype was associated with significant reduction of FSAP activity (P<0.001) and FSAP antigen levels (P=0.04). Patients with DVT showed significantly higher FSAP activity (P=0.008), FSAP antigen (P=0.003), and F1+2 levels (P<0.001) than patients without DVT. The association between the FSAP measures and DVT disappeared when adjusted for CRP levels. F1+2 correlated positively to FSAP antigen (P=0.01), while FVIIa-levels were comparable in patients with and without DVT. We conclude that even though FSAP measures are significantly increased in patients with acute DVT, alterations in the scu-PA activating properties of FSAP are presumably not markedly involved in the development of acute DVT, and that the association between FSAP and DVT disappears after adjustment for CRP.

Activity of recombinant factor VIIa under different conditions in vitro: effect of temperature, pH, and haemodilution.

Recombinant activated factor VII (NovoSeven; Novo Nordisk A/S, Måløv, Denmark) is an effective drug for treatment of bleeding in patients with haemophilia A or B and inhibitors. Little is known about physiological conditions influencing the efficacy of recombinant activated factor VII. We investigated the in-vitro effects of pH, temperature, and haemodilution on the activity of recombinant activated factor VII. Samples from eight healthy volunteers were spiked with recombinant activated factor VII (final concentration 1.7 microg/ml) and adjusted to pH 6.0, 6.5, 7.0, and 7.4 or analysed at 30, 33, 37, and 40 degrees C, or diluted 0, 10, 20, 40, and 60% with dextran before analysis. Samples were analysed as rotational thromboelastometry in whole blood (clotting time, clot formation time, and maximum clot firmness) with and without Innovin (tissue factor), and as factor VII coagulant activity in plasma. Significant effects of pH were observed for clotting time, clot formation time, maximum clot firmness, and factor VII coagulant activity in the direction of longer clot formation times and less firm clots with decreasing pH. Temperature had significant effects on clotting time, clot formation time, and factor VII coagulant activity, but no effects on maximum clot firmness indicating that lower temperatures increase clot formation times without affecting clot firmness. Haemodilution had significant effects on clot formation time, maximum clot firmness, and factor VII coagulant activity, but no effects on clotting time indicating that haemodilution does not affect clot formation, but the clot formed at high haemodilution may not be so firm. In conclusion, the activity of recombinant activated factor VII was affected in vitro by pH, temperature, and haemodilution. Additional studies are necessary to demonstrate that these conditions also affect the efficacy of recombinant activated factor VII therapy in vivo.

Tissue factor pathway inhibitor relates to fibrin degradation in patients with acute deep venous thrombosis.

Reduced concentration of tissue factor pathway inhibitor is a risk factor for development of deep venous thrombosis, whereas elevated concentrations of tissue factor pathway inhibitor are observed in patients with acute myocardial infarction and disseminated intravascular coagulation. Presently, we studied the association between inflammation, endothelial cell perturbation, fibrin degradation and the concentration of tissue factor pathway inhibitor in patients suspected for acute deep venous thrombosis. We determined the tissue factor pathway inhibitor -33T/C polymorphism, free and total tissue factor pathway inhibitor, C-reactive protein, von Willebrand factor and D-Dimer in 160 consecutive patients admitted to hospital with a tentative diagnosis of acute deep venous thrombosis. Deep venous thrombosis was identified in 57 patients (18 distal and 39 proximal). The distribution of the tissue factor pathway inhibitor genotypes between patients with and without deep venous thrombosis showed a trend toward significant deviation (P = 0.08). The concentrations of free and total tissue factor pathway inhibitor, C-reactive protein, von Willebrand factor and D-Dimer were significantly higher in patients with deep venous thrombosis than in patients without deep venous thrombosis (P < 0.001 for all quantities). The significant relationship between free and total tissue factor pathway inhibitor and deep venous thrombosis persisted when adjusted for the tissue factor pathway inhibitor -33T/C polymorphism, C-reactive protein, von Willebrand Factor and potentially confounding clinical conditions (P < or = 0.004), but disappeared when adjusted for D-Dimer (P > or = 0.10). We conclude that patients suffering from acute deep venous thrombosis express significantly higher concentrations of tissue factor pathway inhibitor than patients without deep venous thrombosis. The significant relationship is not associated with the -33T/C polymorphism, inflammation or endothelial cell perturbation, but is most likely related to release of tissue factor pathway inhibitor from fibrin deposits.

Susceptibility to thiamethoxam of Musca domestica from Danish livestock farms.

BACKGROUND: Neonicotinoid baits are currently replacing anticholinesterase baits for control of adult houseflies (Musca domestica L.). Introduction of new insecticides includes evaluation of their cross-resistance potential, which was assessed for thiamethoxam in field populations from Denmark. RESULTS: In feeding bioassay with a susceptible strain, thiamethoxam LC(50) at 72 h was 1.7 microg thiamethoxam g(-1) sugar, making it 19-fold, 11-fold and threefold more toxic to houseflies than azamethiphos, methomyl and spinosad respectively. The field populations were 6-76-fold resistant to thiamethoxam. There was no correlation between the toxicities of thiamethoxam and spinosad, dimethoate, methomyl, bioresmethrin or azamethiphos. The toxicity in feeding bioassay at 72 h of imidacloprid in a susceptible strain was 32 microg imidacloprid g(-1) sugar at LC(50), making it 19-fold less toxic to houseflies than thiamethoxam. There was a strong significant correlation between the toxicities of thiamethoxam and imidacloprid in field populations. CONCLUSION: Neonicotinoid-resistant houseflies were present at a detectable and noticeable level before thiamethoxam and imidacloprid were introduced for housefly control in Denmark. The toxicity of thiamethoxam is explained by other parameters than the toxicities of spinosad, dimethoate, methomyl, bioresmethrin or azamethiphos. The cross-resistance between thiamethoxam and imidacloprid indicates a coincidence of mechanism of the toxicity and resistance in the field populations.

Genetic variation in estrogen receptor, C-reactive protein and fibrinogen does not predict the plasma levels of inflammation markers after longterm hormone replacement therapy.

Markers of inflammation, such as C-reactive protein (CRP) and fibrinogen, are associated with the risk of atherothrombosis. Plasma levels of these markers of inflammation are affected by hormone replacement therapy (HRT) and modulated by smoking. We studied whether genetic variation in the estrogen receptor- 1 (ESR1), CRP and fibrinogen-beta genes influences the plasma levels of inflammation markers after HRT. Plasma CRP and fibrinogen were measured after five years follow-up in healthy postmenopausal women (per-protocol group) who were randomised to hormone therapy (n=187) or no treatment (n=249). The effect of HRT, smoking and genetic variations in ESR1 (PvuII and XbaI), CRP (1444C/T) and fibrinogen-beta (FGB, -455G/A) were determined. The plasma concentration of CRP was higher in the HRT group than in the control group (2.03 mg/l and 1.41 mg/l, respectively; p < 0.001), while the concentration of fibrinogen was lower in the HRT group than in the control group (3.02 g/l and 3.20 g/l, respectively; p < 0.001), indicating that it is unlikely that inflammation is the common underlying pathway. There was a significant interaction between smoking and HRT on the fibrinogen (p=0.02), but not on the CRP concentration (n.s.). Genetic polymorphisms in ESR1, CRP and fibrinogen were not associated with an effect of HRT on the CRP and fibrinogen plasma levels, and no significant interaction with smoking was observed. In conclusion, higher plasma levels of CRP and lower plasma levels of fibrinogen were observed in women using HRT; however, genetic polymorphisms in ESR1, CRP and FGB were not associated with these effects of HRT.

Fibrin clot structure - pro-fibrinolytic effect of oral contraceptives in apparently healthy women.

Fibrin metabolism is influenced by many factors. The velocity of fibrin formation, genetic polymorphisms, fibrinolytic features and the structure of the fibrin clot are determinants of fibrin turnover. Oral contraceptives (OCs) have significant impact on the haemostatic system, by increasing the concentration of coagulation factors, plasminogen and tissue plasminogen activator activity, and decreasing the concentration of haemostatic inhibitors. The present study addresses the influence of OCs on fibrin structure and fibrin metabolism. The study included 70 women treated with seven different OC-formulations. Blood was collected at baseline and after six months of OCs. The plasma concentration of fibrinogen, thrombin-antithrombin complex (TAT), plasminogen, plasmin-antiplasmin complex (PAP), D-Dimer and thrombin generation measures were determined. Fibrin structure measures and fibrin clot lysis not affected by the plasma concentration of plasminogen activators and inhibitors were determined. OCs increased the concentration of fibrinogen, TAT, plasminogen, PAP and D-dimer significantly and affected measures of thrombin generation (p<0.001). The maximal optical density of fibrin (p<0.001), the fibrin fibre density (p=0.03), fibrin fibre diameter (p=0.003), fibrin mass-length ratio (p<0.001) and lysis per hour (p<0.001) increased significantly upon OC-treatment. Lysis per hour was not correlated to the concentration of plasminogen. We conclude that the effect of OCs on the coagulation system is balanced by alterations in fibrin structure, facilitating clot lysis and contributing to the fibrinolytic susceptibility already present in women treated with OC. These alterations may counterbalance the OC-induced increased thrombin generation and reduced coagulation inhibitory potential, contributing to maintenance of the haemostatic balance in women receiving OCs.

A national field study of quality assessment of CoaguChek point-of-care testing prothrombin time monitors.

A system for quality assessment (QA) of the CoaguChek (Roche Diagnostics, Mannheim, Germany) point-of-care testing prothrombin time monitor has been developed by the European Concerted Action on Anticoagulation. Hitherto there has not been an adequate rapid method for CoaguChek QA. Sets of 5 certified international normalized ratio (INR) plasma samples were tested on 539 CoaguChek monitors by experienced staff at 9 Netherlands Thrombosis Centers and results compared with certified INR. A 15% or more deviation has been classified as significant deviation. Overall mean and certified INR values were similar, but 20.3% of participants showed a 15% or more deviation from the certified INR on at least 1 of the 5 QA plasma samples. Statistically significant differences in results with different lots of CoaguChek test strips were found. There is need for large scale QA of CoaguChek monitors. The importance of the 5 CoaguChek certified INR QA plasma samples being tested on a single occasion is demonstrated.

Survey of permethrin and malathion resistance in human head lice populations from Denmark.

Head lice, Pediculis capitis De Geer, populations were investigated for permethrin and malathion resistance after initial establishment of a discriminating dose of topical application bioassay with body lice, Pediculus humanus L. For both insecticides, approximately 2 times the lethal dose (LD)95 at 4 h was selected, 2 ng of permethrin and 100 ng of malathion per head louse, respectively. Head lice were collected from heads of infested children in Denmark at 33 primary schools, one kindergarten, and seven boarding schools. The lice were collected by combing of dry hair, with a fine-toothed antilouse comb attached to a vacuum cleaner. A resistance survey covers head lice collected from 208 of 1,441 persons combed. The frequency of permethrin- and malathion-resistant head lice is high in Danish head lice populations. In 17 of 24 samples tested for permethrin resistance, all head lice survived the discriminating dose. Six samples had between 3 and 25% dead head lice, whereas one sample had 60% mortality. In nine of 25 samples tested for malathion resistance, all head lice survived the discriminating dose. Seven samples had <25% dead head lice, and four samples had a mortality of 50% or more at the discriminating dose. The connection between permethrin resistance and kdr-like mutations is confirmed by our findings. The frequency of the double mutation T929I-L932 F in the voltage-sensitive sodium channel gene associated with permethrin resistance was 0.95 in Danish head lice populations.

Variation of Musca domestica L. acetylcholinesterase in Danish housefly populations.

Anti-cholinesterase resistance is in many cases caused by modified acetylcholinesterase (MACE). A comparison was made of toxicological data and AChE activity gathered from 21 field populations and nine laboratory strains of houseflies, Musca domestica L., to elucidate the best way of generating data to provide advice for management strategies and gathering information for resistance risk assessment on the organophosphates azamethiphos and dimethoate and the carbamate methomyl, which have been the primary insecticides used against adult houseflies in Denmark. Cluster analysis was performed and > 2000 houseflies were assigned to one of three phenotypes based on total acetylcholinesterase activity as well as inhibition by azamethiphos, methomyl or omethoate. A cluster, i.e. a phenotype, with high total AChE activity and high sensitivity to azamethiphos and less sensitivity to inhibition by methomyl and omethoate was shown to be linked to methomyl resistance. It was not possible to define any clusters that could be linked to azamethiphos or dimethoate resistance. The five mutations V180L, G262A, G262V, F327Y and G365A causing anticholinesterase resistance in houseflies were all identified in the Danish housefly strains. The data are very heterogeneous, and a correlation of molecular genetic background and resistance of phenotypes is not obvious with the available data.