Major bleeding risks of different low-molecular-weight heparin agents: a cohort study in 12 934 patients treated for acute venous thrombosis.

Essentials Low-molecular-weight-heparins (LMWH) kinetics differ which may result in different bleeding risks. A cohort of 12 934 venous thrombosis patients on LMWH was followed until major bleeding. The absolute major bleeding risk was low among patients registered at the anticoagulation clinic. Once-daily dosing was associated with a lower bleeding risk as compared with twice-daily. SUMMARY: Background Low-molecular-weight heparins (LMWHs) are considered members of a class of drugs with similar anticoagulant properties. However, pharmacodynamics and pharmacokinetics between LMWHs differ, which may result in different bleeding risks. As these agents are used by many patients, small differences may lead to a large effect on numbers of major bleeding events. Objectives To determine major bleeding risks for different LMWH agents and dosing schedules. Methods A cohort of acute venous thrombosis patients from four anticoagulation clinics who used an LMWH and a vitamin K antagonist were followed until they ceased LMWH treatment or until major bleeding. Exposures were classified according to different types of LMWHs and for b.i.d. and o.d. use. Cumulative incidences for major bleeding per 1000 patients and risk ratios were calculated and adjusted for study center. Results The study comprised 12 934 patients with a mean age of 59 years; 6218 (48%) were men. The cumulative incidence of major bleeding was 2.5 per 1000 patients (95% confidence interval [CI], 1.7-3.5). Enoxaparin b.i.d. or o.d. was associated with a relative bleeding risk of 1.7 (95% CI, 0.2-17.5) compared with nadroparin o.d. In addition, a nadroparin b.i.d. dosing schedule was associated with a 2.0-fold increased major bleeding risk (95% CI, 0.8-5.1) as compared with a nadroparin o.d. dosing schedule. Conclusions Absolute major bleeding rates were low for all LMWH agents and dosing schedules in a large unselected cohort. Nevertheless, twice-daily dosing with nadroparin appeared to be associated with an increased major bleeding risk as compared with once-daily dosing, as also suggested in a meta-analysis of controlled clinical trials.

Monitoring of treatment with vitamin K antagonists: recombinant thromboplastins are more sensitive to factor VII than tissue-extract thromboplastins.

Essentials Differences in sensitivity to factor VII (FVII) have been suggested between thromboplastins. FVII-induced International Normalized Ratio (INR) changes differ between commercial reagents. Recombinant human thromboplastins are more sensitive to FVII than tissue-extract thromboplastins. Thromboplastin choice may affect FVII-mediated INR stability. SUMMARY: Background Differences regarding sensitivity to factor VII have been suggested for recombinant human and tissue-extract thromboplastins used for International Normalized Ratio (INR) measurement, but the evidence is scarce. Differences in FVII sensitivity are clinically relevant, as they can affect INR stability during treatment with vitamin K antagonists (VKAs). Objectives To determine whether commercial thromboplastins react differently to changes in FVII. Methods We studied the effect of addition of FVII on the INR in plasma by using three tissue-extract (Neoplastin C1+, Hepato Quick, and Thromborel S) and three recombinant human (Recombiplastin 2G, Innovin, and CoaguChek XS) thromboplastins. Three different concentrations of purified human FVII (0.006, 0.012 and 0.062 µg mL-1 plasma), or buffer, were added to five certified pooled plasmas of patients using VKAs (INR of 1.5-3.5). Changes in FVII activity were measured with two bioassays (Neoplastin and Recombiplastin), and relative INR changes were compared between reagents. Results After addition of 0.062 µg mL-1 FVII, FVII activity in the pooled plasmas increased by approximately 20% (Neoplastin) or 32% (Recombiplastin) relative to the activity in pooled normal plasma. All thromboplastins showed dose-dependent INR decreases. The relative INR change in the pooled plasmas significantly differed between the six thromboplastins. No differences were observed among recombinant or tissue-extract thromboplastins. Pooled results indicated that the FVII-induced INR change was greater for recombinant than for tissue-extract thromboplastins. Conclusions Differences regarding FVII sensitivity exist between various thromboplastins used for VKA monitoring. Recombinant human thromboplastins are more sensitive to FVII than tissue-extract thromboplastins. Therefore, thromboplastin choice may affect FVII-mediated INR stability.

Statin use decreases coagulation in users of vitamin K antagonists.

PURPOSE: The purpose of the study is to determine the immediate and long-term effect of statins on coagulation in patients treated with vitamin K antagonists (VKAs). METHODS: We selected patients on VKAs of two Dutch anticoagulation clinics who initiated treatment with a statin between 2009 and 2013. Patients who initiated or stopped concomitant drugs that interact with VKAs or were hospitalised during follow-up were excluded. The VKA dosage (mg/day) after statin initiation was compared with the last VKA dosage before the statin was started. Immediate and long-term differences in VKA dosage (at 6 and 12 weeks) were calculated with a paired student t test. RESULTS: Four hundred thirty-five phenprocoumon users (mean age 70 years, 60 % men) and 303 acenocoumarol users (mean age 69 years, 58 % men) were included. After start of statin use, the immediate phenprocoumon dosage was 0.02 mg/day (95 % CI, 0.00 to 0.03) lower. At 6 and 12 weeks, these phenprocoumon dosages were 0.03 (95 % CI, 0.01 to 0.05) and 0.07 mg/day (95 % CI, 0.04 to 0.09) lower as compared with the dosage before first statin use. In acenocoumarol users, VKA dosage was 0.04 mg/day (95%CI, 0.01 to 0.07) (immediate effect), 0.10 (95 % CI, 0.03 to 0.16) (at 6 weeks), and 0.11 mg/day (95 % CI, 0.04 to 0.18) (after 12 weeks) lower. CONCLUSIONS: Initiation of statin treatment was associated with an immediate and long-term minor although statistically significant decrease in VKA dosage in both phenprocoumon and acenocoumarol users, which suggests that statins may have anticoagulant properties.

Platelet reactivity in patients with venous thrombosis who use rosuvastatin: a randomized controlled clinical trial.

UNLABELLED: Essentials Statins, especially rosuvastatin, may reduce venous thrombosis risk, but the mechanism is unclear. We performed a randomized trial investigating the effect of rosuvastatin on platelet reactivity. Thromboxane-A2 mediated platelet aggregation was measured before and after rosuvastatin therapy. Rosuvastatin did not inhibit thromboxane-mediated platelet aggregation in venous thrombosis patients. SUMMARY: Background Statins may exert a protective effect against the risk of venous thrombosis (VT), but the mechanism is unclear. Objectives In this open-label, randomized clinical trial (www.clinicaltrials.gov NCT01613794), we aimed to determine the ex vivo effect of rosuvastatin on platelet reactivity in patients with a history of VT. Methods Platelet reactivity, in platelet reaction units (PRUs), was measured at baseline and after 28 days with VerifyNow, which uses arachidonic acid to determine thromboxane-mediated platelet aggregation, in 50 consecutive patients included in our study (25 receiving rosuvastatin and 25 without intervention). Results Forty-seven of 50 (94.0%) consecutively enrolled patients had two valid PRU measurements. The mean PRUs in rosuvastatin users were 609 at baseline and 613 at the end of the study (mean change 5; 95% confidence interval [CI] - 18 to 27). The mean PRUs in non-users were 620 at baseline and 618 at the end of the study (mean change - 2; 95% CI - 15 to 12). The mean difference in PRU change between users and non-users was 6 (95% CI - 20 to 33). After exclusion of patients who used antiplatelet medication, or had thrombocytopenia, similar results were obtained, i.e. no apparent effect of rosuvastatin on PRUs, with a mean difference in PRU change between users and non-users of - 1 (95% CI - 20 to 19). Conclusions Rosuvastatin does not affect platelet reactivity when arachidonic acid is used as an agonist in patients with a history of VT.

Impact of point-of-care international normalized ratio monitoring on quality of treatment with vitamin K antagonists in non-self-monitoring patients: a cohort study.

BACKGROUND: Point-of-care (POC) international normalized ratio (INR) monitoring by healthcare professionals could eliminate the need for venous blood sampling in non-self-monitoring (NSM) patients on vitamin K antagonists (VKA). However, few studies have investigated the impact of POC INR monitoring on the quality of treatment in these patients and real-world data on this issue are lacking. OBJECTIVES: To investigate the safety, efficacy and quality of anticoagulant control during POC INR monitoring as compared with laboratory INR monitoring in NSM patients. METHODS: We performed a retrospective cohort study using data from the anticoagulation clinic of the Star-Medical Diagnostic Center (Rotterdam, the Netherlands). Patients who received treatment with VKA between 29 May 2012 and 29 May 2014 were eligible. Percentage of time in therapeutic range (TTR) and incidence rates of major clinical events (all-cause mortality, hospitalization, major bleeding and ischemic stroke) were compared for the year before and year after introduction of POC monitoring. Cox proportional hazard models were used to estimate hazard ratios and 95% confidence intervals for major clinical events between exposure groups. RESULTS: In total, 1973 patients during the 1-year laboratory-monitoring observation period and 1959 patients during the 1-year POC-monitoring observation period were included. Median TTR was significantly lower during POC monitoring (77.9%; 95% CI, 67.2-87.4) than during laboratory INR monitoring (81.0%; 95% CI, 71.1-90.5). Adjusted hazard ratios for major clinical events were all around unity. CONCLUSIONS: Although associated with lower TTR, POC INR monitoring is a safe and effective alternative to laboratory INR monitoring in NSM patients on VKA.

Mental health needs and availability of mental health care for children and adolescents with intellectual disability in Berlin.

BACKGROUND: The increased risk of mental health problems in children and adolescents with intellectual disability (ID) has been reported in several studies. However, almost no research has been conducted on parents' experiences with the general mental health system. We have investigated the prevalence of emotional and behavioural problems in children with ID as well as the availability and quality of mental health care from the parents' point of view. METHODS: Teachers of specialised schools for ID in Berlin were asked to complete the Teacher's Report Form (TRF) of the Child Behavior Checklist. Information was collected for 1226 children and adolescents aged 6-18 years with mild to profound ID (response 70.5%). The availability and quality of mental health care was assessed by a questionnaire given to parents who had already been seeking help for their children. A total of 330 parents completed the questionnaires (response 62.0%). In addition to univariate analysis, we conducted multiple logistic regressions regarding the psychopathology reported by teachers (TRF-syndrome scales) and difficulties concerning mental health care reported by parents for a paired sample of 308 children. RESULTS: Overall, 52.4% of the children and adolescents with ID had a total problem score on the TRF in the deviant range (47.1% when eliminating four items reflecting cognitive deficits). Compared with the general population normative sample of children, this is a three-time higher prevalence. The most striking problems were thought problems (schizoid and obsessive-compulsive), aggressive behaviour, attention problems and social problems. Parents whose children had more severe behavioural or emotional dysfunction reported more difficulties with the mental health system. From the parents' point of view, mental health professionals frequently did not feel responsible or were not sufficiently skilled for the treatment of children with ID. As a consequence, 96% of all parents were longing for specialised in- and outpatient services. CONCLUSIONS: This study confirms the findings from other studies regarding the high rate of co-occurrence of ID and mental health problems in youths. Results indicate that both are strongly requested by parents: specialised in- and outpatient services, as well as more professional general services and equitable treatment for all children, with and without ID.

Developmental changes in pedunculopontine nucleus (PPN) neurons.

The developmental decrease in rapid-eye-movement (REM) sleep in man occurs between birth and after puberty. We hypothesize that if this decrease in REM sleep does not occur, lifelong increases in REM sleep drive may ensue. Such disorders are characterized by hypervigilance and sensory-gating deficits, such as are present in postpubertal onset disorders like schizophrenia, panic attacks (a form of anxiety disorder), and depression. The decrease in REM sleep in the rat occurs between 10 and 30 days of age. We studied changes in size and physiological properties of pedunculopontine nucleus (PPN) cells involved in the control of arousal, i.e., waking and REM sleep. During the largest decrease in REM sleep (12-21 days), cholinergic PPN neurons doubled in cell area, the hypertrophy peaking at 15-16 days, then decreasing in area by 20-21 days. Noncholinergic PPN cells did not change in area during this period. We confirmed the presence of two populations of PPN neurons based on action potential (AP) duration, with the proportion of short-AP-duration cells increasing and long AP duration decreasing between 12 and 21 days. Most cholinergic and noncholinergic cells had short AP durations. Afterhyperpolarization (AHP) duration became segregated into long and short AHP duration after 15 days. Cells with short AP duration also had short AHP duration. The proportion of PPN cells with Ih current increased gradually, peaking at 15 days, then decreased by 21 days. These changes in morphological and physiological properties are discussed in relation to the developmental decrease in REM sleep.

Polyphasic characterization of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (p(HB-co-HV)) metabolizing and denitrifying Acidovorax sp. strains.

For the purpose of denitrification in small drinking water plants, a bacterial mixed population was isolated from a packed bed column bioreactor with poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P(HB-co-HV)) as a substrate for the denitrification of ground water (10 degrees C). Isolates 2nIII from the mixed culture, with the ability to denitrify and metabolize P(HB-co-HV), were used as starter cultures for the elimination of nitrate in ground water. The strains were characterized by diverse techniques. Classical phenotypic studies lead to rRNA group III of the genus Pseudomonas. Results obtained by molecular techniques demonstrated that the 2nIII strains are members of the Comamonadaceae and shows similarities to the genus Acidovorax. However, an integration of the 2nIII isolates within one of the known Acidovorax species is not possible for the moment. The 2nIII starter cultures clustered close to Av. temperans according to their whole cell proteins and fatty acids, whereas in DNA/DNA hybridization no significant DNA binding (< 25%) was found. In contrast a significant but low degree of DNA/DNA hybridization was found between the 2nIII strains and Av. facilis and Av. delafieldii. Our polyphasic results lead to the conclusion that the 2nIII strains may constitute a separate Acicdovorax species.

Interaction between poly-3-hydroxybutyrate-co-3-hydroxyvalerate and a denitrifying Pseudomonas strain.

In a laboratory-scale system, dentrification activity of a heterotrophic microbial starter culture changed when different lots of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P(HB-co-HV)) were used as the solid carbon source in the heterotrophic denitrification reactor. In this study, possible influences of physical and chemical properties of commercially produced P(HB-co-HV) (Biopol) on biofilm formation and metabolic activity of a denitrifying starter culture were investigated. These parameters indicate the polymers' suitability for the application as the matrix substance in the bioreactor. No differences in microstructure were detected between the different lots of polymers. Growth inhibitory effects by chemical additives were found in the case of triacetine, which was included as a plasticizer in seven of eight tested lots. The amount of hydroxyvaleric acid in the polymer was not assumed to affect denitrification activity. Relevant differences could be detected regarding primary adhesion of the starter culture Pseudomonas sp. strain 2nIII. It showed good adsorption properties to hydrophobic substances with a dependence on precultivation conditions. Pseudomonas sp. strain 2nIII degraded poly-3-hydroxybutyrate acid homopolymer and P(HB-co-HV) copolymers but was unable to break up poly-3-hydroxyvaleric acid. A possible reason for these findings is the substrate specifity of the polyhydroxyalkanoate depolymerase.

Mesopontine neurons in schizophrenia.

Findings reported here show that there is a significant increase in the number of neurons in the pedunculopontine nucleus in most schizophrenic patients compared to age-matched controls. Nicotinamide adenine dinucleotide phosphate diaphorase histochemistry was used to label putative cholinergic neurons in the pedunculopontine nucleus and laterodorsal tegmental nucleus, while noradrenergic locus coeruleus neurons were labeled immunocytochemically using an antibody to tryosine hydroxylase. Cell counts of these neuronal groups were carried out using a Biographics image analysis system. We found significantly increased cell numbers in the pedunculopontine nucleus of schizophrenic patients compared to controls. The number of laterodorsal tegmental nucleus neurons was increased but this was not statistically significant. However, the total cell counts for pedunculopontine and laterodorsal tegmental nuclei were significantly higher in schizophrenic subjects. The number of locus coeruleus noradrenergic neurons was similar in both groups. These results implicate the brainstem reticular formation as a pathophysiological site in at least some patients with schizophrenia. In addition, these findings suggest a developmental etiology for the disease and account for some, but not all, of the symptoms of schizophrenia, including sensory gating abnormalities, sleep-wake disturbances and, perhaps, hallucinations. Overdriving of thalamic and substantia nigra function by cholinergic afferents from the midbrain may account for some of the symptoms seen in schizophrenia. These findings suggest that, at least in some schizophrenic patients, there is an increased number of neurons in the cholinergic arm of the reticular activating system. This may explain some of the symptoms of schizophrenia and points to a prenatal disturbance as one of the possible causes of the disease.

Fibroblast growth factor-induced increased survival of cholinergic mesopontine neurons in culture.

Basic fibroblast growth factor (bFGF) was found to increase the survival of immunocytochemically-identified cholinergic mesopontine neurons in dissociated cell cultures of embryonic rat midbrain. In contrast, cultures exposed to, (a) bFGF and an antibody to bFGF, (b) antibody to bFGF alone, or (c) untreated, contained approximately half the number of cholinergic neurons compared to bFGF-treated cultures.

The brain stem reticular formation in schizophrenia.

Post-mortem brain tissue was obtained from four patients with schizophrenia and five controls to study cell groups in the brain stem reticular formation. Cholinergic neurons in the pedunculopontine nucleus (PPN) and lateral dorsal tegmental nucleus (LDT) were labeled using nicotinamide adenosine dinucleotide phosphate (NADPH)-diaphorase histochemistry, while catecholaminergic neurons of the locus ceruleus (LC) were labeled immunocytochemically using an antibody to tyrosine hydroxylase. In schizophrenic patients, there were increased numbers of neurons in the PPN labeled by NADPH-diaphorase and reduced cell size in the LC. These results implicate the reticular formation as a possible pathophysiological site for at least some patients with schizophrenia. This also suggests that some of the deficits observed may be based on faulty neurodevelopment.

Locomotor projections from the pedunculopontine nucleus to the medioventral medulla.

Retrograde tracers were injected into the rat medioventral medulla (MED) and the injection site was identified as a locomotion- inducing area by electrical stimulation in the decerebrate preparation. Histological reconstructions showed that about 10% of cholinergic pedunculopontine (PPN) and laterodorsal tegmental (LDT) neurons project to the MED. Also, large numbers of non-cholinergic cells in and around the PPN and LDT were found to project to the MED.

Two stereoisomeric imidazoline derivatives: synthesis and optical and alpha 2-adrenoceptor activities.

Two eight-step pathways for synthesizing the stereoisomeric compounds (-)-2-[1-(2,6-dichlorophenoxy)ethyl]-2-imidazoline hydrochloride ("levlofexidine" hydrochloride; (-)-lofexidine hydrochloride) and (+)-2-[1-(2,6-dichlorophenoxy)ethyl]-2-imidazoline hydrochloride ("dexlofexidine" hydrochloride; (+)-lofexidine hydrochloride) and the optical resolution of (+/-)-lofexidine are described. (-)-Lofexidine, a stereoselective alpha 2-adrenoceptor agonist, due to its center of asymmetry, is demonstrated to be a potent drug for the treatment of hypertension (doses 0.561 microgram/kg) and to have the highest affinity and a concentration dependency for alpha 2-adrenoceptors in direct binding studies (0.36 nmol/L). (+)-Lofexidine is 10 times less potent.

Chemistry of lofexidine.

The systematic syntheses and pharmacological studies of numerous imidazolines aryloxyalkyl-substituted in the 2-position show that substitution of the aryl residue in the 2,6-position by halogen and addition of a side-chain to the alkyl residue results in compounds with marked antihypertensive activity. 2-[1-(2,6-Dichlorphenoxy)-ethyl-2-imidazoline hydrochloride (lofexidine, Lofetensin and Loxacor) exhibits the most marked hypotensive activity. The synthesis and physico-chemical properties of lofexidine are described.