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1.
Med Vet Entomol ; 33(3): 407-419, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31032960

RESUMO

In total, 366 birds representing 55 species in 24 families and eight orders, were examined for chewing lice (Phthiraptera: Amblycera, Ischnocera) in two high-altitude localities in Yunnan Province, China. In Ailaoshan, almost all of the birds examined were resident passeriforms, of which 36% were parasitized by chewing lice. In Jinshanyakou, most birds were on migration, and included both passerine and non-passerine birds. Of the passerine birds caught in Jinshanyakou, only one bird (0.7%) was parasitized by chewing lice. The prevalence of Myrsidea and Brueelia-complex lice on birds caught in Ailaoshan was higher than in previous reports. Of the chewing lice identifiable to species level, three represent new records for China: Actornithophilus hoplopteri (Mjöberg, 1910), Maculinirmus ljosalfar Gustafsson & Bush, 2017 and Quadraceps sinensis Timmermann, 1954. In total, 17 new host records are included, of which we describe two as new species in the Brueelia-complex: Guimaraesiella (Cicchinella) ailaoshanensis sp. nov. ex Schoeniparus dubius dubius (Hume, 1874) and G. (C.) montisodalis sp. nov. ex Fulvetta manipurensis tonkinensis Delacour & Jabouille, 1930. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:9FC3D8EE-2CED-4DBE-A1DB-471B71260D27.


Assuntos
Altitude , Amblíceros/fisiologia , Doenças das Aves/epidemiologia , Aves , Iscnóceros/fisiologia , Infestações por Piolhos/veterinária , Distribuição Animal , Migração Animal , Animais , Doenças das Aves/parasitologia , China/epidemiologia , Infestações por Piolhos/epidemiologia , Infestações por Piolhos/parasitologia , Prevalência , Especificidade da Espécie
2.
Clin Exp Immunol ; 191(2): 240-251, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28984903

RESUMO

A child, 2 years with the 'hypercalprotectinaemia with hyperzincaemia' clinical syndrome, presented with atypical symptoms and signs, notably persistent fever of approximately 38°C, thrombocythaemia of > 700 × 109 /l and a predominance of persistent intestinal symptoms. In an effort to find a cure by identifying the dysregulated pathways we analysed whole-genome mRNA expression by the Affymetrix HG U133 Plus 2·0 array in blood on three occasions 3-5 months apart. Major up-regulation was demonstrated for the Janus kinase/signal transducer and activators of transcription (JAK/STAT) pathway including, in particular, CD177, S100A8, S100A9 and S100A12, accounting for the thrombocytosis; a large number of interleukins, their receptors and activators, accounting for the febrile apathic state; and the high mobility group box 1 (HMBG1) gene, possibly accounting for part of the intestinal symptoms. These results show that gene expression array technology may assist the clinician in the diagnostic work-up of individual patients with suspected syndromal states of unknown origin, and the expression data can guide the selection of optimal treatment directed at the identified target pathways.


Assuntos
Proteínas Sanguíneas/genética , Complexo Antígeno L1 Leucocitário/metabolismo , Erros Inatos do Metabolismo dos Metais/diagnóstico , Pré-Escolar , Tomada de Decisão Clínica , Feminino , Febre , Gastroenteropatias , Estudo de Associação Genômica Ampla , Humanos , Complexo Antígeno L1 Leucocitário/genética , Erros Inatos do Metabolismo dos Metais/genética , Análise em Microsséries , Patologia Molecular , Transdução de Sinais , Trombocitose , Sequenciamento Completo do Genoma
3.
Med Vet Entomol ; 30(2): 200-8, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26753998

RESUMO

Documenting patterns of host specificity in parasites relies on the adequate definition of parasite species. In many cases, parasites have simplified morphology, making species delimitation based on traditional morphological characters difficult. Molecular data can help in assessing whether widespread parasites harbour cryptic species and, alternatively, in guiding further taxonomic revision in cases in which there is morphological variation. The duck louse genus Anaticola (Phthiraptera: Philopteridae), based on current taxonomy, contains both host-specific and widespread species. Mitochondrial and nuclear DNA sequences of samples from this genus were used to document patterns of host specificity. The comparison of these patterns with morphological variations in Anaticola revealed a general correspondence between the groups identified by DNA sequences and morphology, respectively. These results suggest that a more thorough taxonomic review of this genus is needed. In general, the groups identified on the basis of molecular data were associated with particular groups of waterfowl (e.g. dabbling ducks, sea ducks, geese) or specific biogeographic regions (e.g. North America, South America, Australia, Eurasia).


Assuntos
Doenças das Aves/parasitologia , Patos , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Infestações por Piolhos/veterinária , Ftirápteros/fisiologia , Animais , Núcleo Celular/genética , DNA/genética , DNA Mitocondrial/genética , Feminino , Infestações por Piolhos/parasitologia , Masculino , Ftirápteros/genética , Filogenia , Análise de Sequência de DNA/veterinária , Especificidade da Espécie
4.
J Thromb Haemost ; 13(8): 1494-502, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26096765

RESUMO

BACKGROUND: Based on animal and human data, phosphoinositide 3-kinase (PI3K)ß is a promising antithrombotic target. However, the relation between efficacy and bleeding when combined with current antiplatelet therapies is unclear. OBJECTIVE: To strengthen the PI3Kß target validation using the short-acting inhibitor AZD6482 alone and in different combinations with P2Y12 and cyclooxygenase (COX)-1 inhibition in vitro (human platelets), in vivo (dog), and in healthy subjects. METHODS AND RESULTS: Evaluation of complete target inhibition of PI3Kß (by AZD6482), P2Y12 (by ticagrelor), and COX-1 (by aspirin) alone and in the different combinations vs. concentration responses for a panel of platelet agonists in vitro (adenosine diphosphate, collagen, thrombin receptor activating peptide) indicates that the rank order of antiplatelet efficacy is P2Y12  > PI3Kß > COX-1 as monotherapy and P2Y12 plus PI3Kß > P2Y12 plus COX-1 > PI3Kß plus COX-1 as dual therapy, with little additional effect with triple therapy. Use of a conscious dog model to assess ex vivo antiplatelet effect in parallel with bleeding time prolongation (standard incision in the ear) confirms the wide separation of efficacy vs. bleeding for PI3Kß inhibition and that this separation is reduced when combined with aspirin and more reduced when combined with clopidogrel. In healthy subjects, AZD6482, in combination with aspirin, shows a potential for greater antiplatelet potency but less bleeding potential compared with clopidogrel plus aspirin. CONCLUSIONS: PI3Kß inhibition, in comparison with P2Y12 and COX-1, delivers medium antiplatelet effect but with minimal bleeding. PI3Kß inhibition, in combination with aspirin, in healthy subjects, provides a potential for greater overall antiplatelet effect compared with clopidogrel plus aspirin, but with significantly less bleeding potential.


Assuntos
Adenosina/análogos & derivados , Aspirina/administração & dosagem , Plaquetas/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase/administração & dosagem , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores da Agregação Plaquetária/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Antagonistas do Receptor Purinérgico P2Y/administração & dosagem , Pirimidinonas/administração & dosagem , ortoaminobenzoatos/administração & dosagem , Adenosina/administração & dosagem , Adenosina/efeitos adversos , Adulto , Animais , Aspirina/efeitos adversos , Plaquetas/enzimologia , Estudos Cross-Over , Ciclo-Oxigenase 1/sangue , Inibidores de Ciclo-Oxigenase/efeitos adversos , Cães , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Hemorragia/induzido quimicamente , Humanos , Masculino , Modelos Animais , Fosfatidilinositol 3-Quinase/sangue , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/efeitos adversos , Testes de Função Plaquetária , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/farmacocinética , Antagonistas do Receptor Purinérgico P2Y/efeitos adversos , Pirimidinonas/efeitos adversos , Pirimidinonas/farmacocinética , Receptores Purinérgicos P2Y12/sangue , Receptores Purinérgicos P2Y12/efeitos dos fármacos , Suécia , Ticagrelor , Adulto Jovem , ortoaminobenzoatos/efeitos adversos , ortoaminobenzoatos/farmacocinética
5.
J Thromb Haemost ; 13(7): 1293-300, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25944555

RESUMO

BACKGROUND: The present study was carried out to investigate the impact of FII levels, and their increase, on the hemostatic potential in plasma from hemophilia A and B patients with and without inhibitors. METHOD: Recombinant human factor (F) II (rhFII) was added ex vivo to plasma from 68 patients with hemophilia A and B, with or without inhibitors. The hemostatic potential as measured by thrombin generation (calibrated automated thrombogram [CAT]) was focused on the endogenous thrombin potential (ETP) as it has been shown to correlate with the clinical phenotype of bleeding in hemophilia patients and has also been used to guide bypassing therapy in hemophilia patients with inhibitors before elective surgery. The factor eight inhibitor bypassing agent (FEIBA(®) ) was used as a reference to the clinical situation. RESULTS: The study shows that rhFII concentration-dependently increased ETP by a similar magnitude in hemophilia A and B, both with and without inhibitors. Compared with FEIBA, rhFII showed a shallower concentration-response curve. In both types of hemophilia 100 mg L(-1) of rhFII roughly doubled the ETP. A corresponding response was obtained by 0.5 U mL(-1) of FEIBA. CONCLUSION: These data support the theory that FII is one of the major components responsible for the efficacy of FEIBA. The data also indicate that rhFII may be useful, alone or in combination with other coagulation factors, in some of the conditions for which FEIBA is used today, although more data are needed to substantiate this.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Coagulantes/farmacologia , Hemofilia A/sangue , Hemofilia B/sangue , Protrombina/farmacologia , Trombina/metabolismo , Adolescente , Adulto , Idoso , Anticorpos Neutralizantes/sangue , Autoanticorpos/sangue , Fatores de Coagulação Sanguínea/farmacologia , Testes de Coagulação Sanguínea , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Fator VIII/imunologia , Hemofilia A/diagnóstico , Hemofilia A/tratamento farmacológico , Hemofilia A/imunologia , Hemofilia B/diagnóstico , Hemofilia B/tratamento farmacológico , Hemofilia B/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/farmacologia , Índice de Gravidade de Doença , Fatores de Tempo , Adulto Jovem
6.
Nat Nanotechnol ; 8(1): 25-30, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23223187

RESUMO

The symmetry of Cooper pairs is central to constructing a superconducting state. The demonstration of a d(x²-y²)-wave order parameter with nodes represented a breakthrough for high critical temperature superconductors (HTSs). However, despite this fundamental discovery, the origin of superconductivity remains elusive, raising the question of whether something is missing from the global picture. Deviations from d(x²-y²)-wave symmetry, such as an imaginary admixture d(x²-y²)+ is (or id(xy)), predict a ground state with unconventional properties exhibiting a full superconducting gap and time reversal symmetry breaking. The existence of such a state, until now highly controversial, can be proved by highly sensitive measurements of the excitation spectrum. Here, we present a spectroscopic technique based on an HTS nanoscale device that allows an unprecedented energy resolution thanks to Coulomb blockade effects, a regime practically inaccessible in these materials previously. We find that the energy required to add an extra electron depends on the parity (odd/even) of the excess electrons on the island and increases with magnetic field. This is inconsistent with a pure d(x²-y²)-wave symmetry and demonstrates a complex order parameter component that needs to be incorporated into any theoretical model of HTS.

7.
J Thromb Haemost ; 10(10): 2127-36, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22906130

RESUMO

BACKGROUND: Based on in vitro and animal data, PI3Kß is given an important role in platelet adhesion and aggregation but its role in insulin signaling is unclear. OBJECTIVE: To strengthen the PI3Kß target validation using the novel, short-acting inhibitor AZD6482. METHODS AND RESULTS: AZD6482 is a potent, selective and ATP competitive PI3Kß inhibitor (IC(50) 0.01 µm). A maximal anti-platelet effect was achieved at 1 µm in the in vitro and ex vivo tests both in dog and in man. In dog, in vivo AZD6482 produced a complete anti-thrombotic effect without an increased bleeding time or blood loss. AZD6482 was well tolerated in healthy volunteers during a 3-h infusion. The ex vivo anti-platelet effect and minimal bleeding time prolongation in the dog model translated well to data obtained in healthy volunteers. AZD6482 inhibited insulin-induced human adipocyte glucose uptake in vitro (IC(50) of 4.4 µm). In the euglycemic hyperinsulinemic clamp model, in rats, glucose infusion rate was not affected at 2.3 µm but reduced by about 60% at a plasma exposure of 27 µm. In man, the homeostasis model analysis (HOMA) index increased by about 10-20% at the highest plasma concentration of 5.3 µm. CONCLUSIONS: This is the first human target validation for PI3Kß inhibition as anti-platelet therapy showing a mild and generalized antiplatelet effect attenuating but not completely inhibiting multiple signaling pathways with an impressive separation towards primary hemostasis. AZD6482 at 'supratherapeutic' plasma concentrations may attenuate insulin signaling, most likely through PI3Kα inhibition.


Assuntos
Plaquetas/efeitos dos fármacos , Fibrinolíticos/farmacologia , Hemostáticos/farmacologia , Resistência à Insulina , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores da Agregação Plaquetária/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinonas/farmacologia , ortoaminobenzoatos/farmacologia , Adipócitos/efeitos dos fármacos , Adipócitos/enzimologia , Adolescente , Adulto , Animais , Tempo de Sangramento , Plaquetas/enzimologia , Linhagem Celular Tumoral , Classe Ia de Fosfatidilinositol 3-Quinase/sangue , Modelos Animais de Doenças , Cães , Relação Dose-Resposta a Droga , Método Duplo-Cego , Fibrinolíticos/administração & dosagem , Fibrinolíticos/efeitos adversos , Fibrinolíticos/farmacocinética , Glucose/metabolismo , Hemostasia/efeitos dos fármacos , Hemostáticos/administração & dosagem , Hemostáticos/efeitos adversos , Hemostáticos/farmacocinética , Humanos , Masculino , Fosforilação , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/administração & dosagem , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/farmacocinética , Testes de Função Plaquetária , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirimidinonas/administração & dosagem , Pirimidinonas/efeitos adversos , Pirimidinonas/farmacocinética , Ratos , Transdução de Sinais/efeitos dos fármacos , Trombose/sangue , Trombose/prevenção & controle , Fatores de Tempo , Adulto Jovem , ortoaminobenzoatos/administração & dosagem , ortoaminobenzoatos/efeitos adversos , ortoaminobenzoatos/farmacocinética
8.
Nano Lett ; 10(12): 4824-9, 2010 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-21080664

RESUMO

We have developed a new method to fabricate biepitaxial YBa2 Cu3 O7-δ (YBCO) Josephson junctions at the nanoscale, allowing junctions widths down to 100 nm and simultaneously avoiding the typical damage in grain boundary interfaces due to conventional patterning procedures. By using the competition between the superconducting YBCO and the insulating Y2 BaCuO5 phases during film growth, we formed nanometer sized grain boundary junctions in the insulating Y2 BaCuO5 matrix as confirmed by high-resolution transmission electron microscopy. Electrical transport measurements give clear indications that we are close to probing the intrinsic properties of the grain boundaries.

10.
Acta Paediatr ; 94(6): 682-8, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16188769

RESUMO

AIM: In Sweden, paediatricians or general practitioners treat most adolescents with asthma. This study compares management, treatment goals and quality of life for adolescents aged 15-18 y in paediatric or primary care. MATERIAL AND METHODS: A random sample of patients answered a disease-specific and a quality-of-life (MiniAQLQ) questionnaire. RESULTS: The 146 adolescents in paediatric care had more years with asthma, better continuity of annual surveillance, higher use of inhaled steroids and a stated better knowledge of their asthma than the 174 patients in primary care. No difference could be detected in asthma control or quality of life. Of all 320 adolescents, approximately 20% had woken at night due to asthma symptoms during the last week. About 15% had made unscheduled, urgent care visits and a third had used short-acting beta-agonist relievers more than twice a week. Quality-of-life scores were high and similar in both settings. CONCLUSIONS: Swedish adolescents with asthma are managed and treated somewhat differently in paediatric and primary care but with equal and, for the most part, satisfying results. The difference between the two settings probably reflects both differences in severity of asthma and different treatment traditions. For all adolescents, better fulfilment of goals regarding symptoms and exacerbations would be desirable, whereas a good quality of life including normal physical activity seems to have been achieved.


Assuntos
Asma/terapia , Qualidade de Vida , Adolescente , Asma/psicologia , Criança , Serviços de Saúde da Criança , Estudos Transversais , Humanos , Atenção Primária à Saúde , Suécia
11.
J Intern Med ; 254(4): 322-34, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12974871

RESUMO

Thrombin has long been a target for development of oral anticoagulants but it has been difficult to find synthetic inhibitors with a desirable combination of pharmacodynamic and pharmacokinetic properties. However, there are now two oral direct thrombin inhibitors (DTIs) in clinical development, ximelagatran (ExantaTM) and BIBR 1048. Both are prodrugs with two protecting groups that are eliminated after absorption from the gastrointestinal tract. Their main active substances, melagatran and BIBR 953, are both potent and selective DTIs. In experimental models of thrombosis, melagatran has been shown to have a shallower dose-response curve than warfarin and, therefore, a better separation between efficacy and bleeding. Oral bioavailability, measured as the plasma concentration of the active metabolite, seems to be higher for ximelagatran (20%) than for BIBR 1048 (estimated to 5%). BIBR 953 has a longer half-life (about 12 h) than does melagatran (3-5 h) after oral administration of BIBR 1048 and ximelagatran, respectively. Both melagatran and BIBR 953 are mainly eliminated via the renal route. The variability of the plasma concentration of melagatran after oral administration of ximelagatran is low. There are no clinically relevant interactions with food or cytochrome P450 metabolized drugs and ximelagatran. In clinical studies, ximelagatran has been administered in a twice-daily fixed-dose regimen without coagulation monitoring. Results of published clinical studies are encouraging, both with regard to efficacy and bleeding. Major indications in Phase III studies with ximelagatran are the prevention of venous thromboembolism (VTE) in hip and knee replacement surgery, treatment and long-term secondary prevention of VTE and prevention of stroke in patients with nonvalvular atrial fibrillation. It is anticipated that with a favourable outcome of the Phase III clinical studies new oral DTIs, with the oral fixed-dose regimen without routine coagulation monitoring, will ease the use of today's anticoagulant therapy.


Assuntos
Anticoagulantes/uso terapêutico , Glicina/análogos & derivados , Trombina/antagonistas & inibidores , Trombose/prevenção & controle , Azetidinas/química , Azetidinas/farmacocinética , Azetidinas/uso terapêutico , Benzimidazóis/uso terapêutico , Benzilaminas , Dabigatrana , Glicina/farmacocinética , Glicina/uso terapêutico , Hemostasia/efeitos dos fármacos , Humanos , Pró-Fármacos/uso terapêutico , Piridinas/uso terapêutico , Acidente Vascular Cerebral/prevenção & controle , Trombose Venosa/prevenção & controle , Vitamina K/antagonistas & inibidores
12.
J Thromb Haemost ; 1(5): 999-1004, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12871368

RESUMO

BACKGROUND: Thrombin plays a major role in thrombus formation through activation of platelets and conversion of fibrinogen to fibrin. OBJECTIVES: To investigate the antithrombotic effects of the oral direct thrombin inhibitor (DTI) ximelagatran and the parenteral DTI r-hirudin in humans. SUBJECTS AND METHODS: Healthy male volunteers randomized into four parallel groups each with 15 subjects received either ximelagatran (20, 40 or 80 mg orally) or r-hirudin (0.4 mg kg-1 intravenous bolus + infusion of 0.15 mg kg-1 h-1 for 2 h and 0.075 mg kg-1 h-1 for 3 h). Antithrombotic effects were assessed as changes in total thrombus area (TTA) and total fibrin area (TFA) from baseline, using the Badimon perfusion chamber model at baseline and 2 h and 5 h after drug administration. RESULTS: Two hours postdosing, ximelagatran showed antithrombotic effects at both high and low shear rates (TTA% of mean baseline value +/- SEM was 76 +/- 13% and 71 +/- 17% [both P < 0.05] for the 20-mg dose, 85 +/- 11% [P > 0.05] and 62 +/- 15% [P < 0.05] for the 40-mg dose and 60 +/- 11% and 26 +/- 7% [both P < 0.05] for the 80-mg dose, respectively). r-Hirudin also showed a significant antithrombotic effect at high and low shear rates (76 +/- 11% [P = 0.05] and 57 +/- 17% [P < 0.05] of baseline values, 2 h postdosing, respectively). The inhibitory effects on TFA were similar to those on TTA. CONCLUSIONS: The oral DTI ximelagatran shows antithrombotic effects under both high and low shear conditions. The antithrombotic effect of 40-80 mg ximelagatran appeared comparable to that of parenterally administered r-hirudin, which has been previously demonstrated to be clinically effective in acute coronary syndromes.


Assuntos
Azetidinas/farmacocinética , Fibrinolíticos/farmacocinética , Trombina/antagonistas & inibidores , Trombose/prevenção & controle , Adulto , Arteriopatias Oclusivas/tratamento farmacológico , Arteriopatias Oclusivas/prevenção & controle , Azetidinas/administração & dosagem , Azetidinas/farmacologia , Benzilaminas , Testes de Coagulação Sanguínea , Fibrina/efeitos dos fármacos , Fibrinolíticos/administração & dosagem , Fibrinolíticos/farmacologia , Hirudinas/administração & dosagem , Hirudinas/farmacologia , Humanos , Masculino , Perfusão , Farmacocinética , Estresse Mecânico , Trombose/tratamento farmacológico , Veias
13.
J Thromb Haemost ; 1(1): 41-7, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12871538

RESUMO

This randomized, controlled, multicentre study evaluated the efficacy and tolerability of the oral direct thrombin inhibitor ximelagatran, compared with a low-molecular-weight heparin (dalteparin) followed by warfarin, in the treatment of deep vein thrombosis (DVT) of the lower extremity. Patients with acute DVT received oral ximelagatran (24, 36, 48 or 60 mg twice daily) or dalteparin and warfarin for 2 weeks. Evaluation of paired venograms from 295 of 350 patients showed regression of the thrombus in 69% of patients treated with ximelagatran and 69% of patients treated with dalteparin and warfarin. Progression was observed in 8% and 3% of patients, respectively. Changes in thrombus size according to the Marder score were similar in all groups. Treatment discontinuation due to bleeding occurred in two patients receiving ximelagatran (24- and 36-mg groups) and in two patients receiving dalteparin and warfarin. Reduction in pain, edema and circumference of the affected leg was similar in all groups. Oral ximelagatran appears to be a promising alternative to current anticoagulant therapy to limit the progression of acute DVT, and it seems to possess a wide therapeutic window.


Assuntos
Anticoagulantes/administração & dosagem , Azetidinas/administração & dosagem , Dalteparina/administração & dosagem , Trombose Venosa/tratamento farmacológico , Varfarina/administração & dosagem , Doença Aguda , Administração Oral , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Benzilaminas , Relação Dose-Resposta a Droga , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Perna (Membro)/irrigação sanguínea , Masculino , Pessoa de Meia-Idade , Flebografia , Pró-Fármacos/administração & dosagem , Cintilografia , Resultado do Tratamento , Trombose Venosa/diagnóstico por imagem
15.
Thromb Haemost ; 87(4): 580-5, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12008938

RESUMO

Patients (n = 1600) from 12 European countries, scheduled for elective orthopaedic hip or knee surgery, were screened for Factor V Leiden and prothrombin gene G20210A mutations, found in 5.5% and 2.9% of the populations, respectively. All patients underwent prophylactic treatment with one of four doses of melagatran and ximelagatran or dalteparin, starting pre-operatively. Bilateral ascending venography was performed on study day 8-11. The patients were subsequently treated according to local routines and followed for 4-6 weeks postoperatively. The composite endpoint of screened deep vein thrombosis (DVT) and symptomatic pulmonary embolism (PE) during prophylaxis did not differ significantly between patients with or without these mutations. Symptomatic venous thromboembolism (VTE) during prophylaxis and follow-up (1.9%) was significantly over-represented among patients with the prothrombin gene G20210A mutation (p = 0.0002). A tendency towards increased risk of VTE was found with the Factor V Leiden mutation (p = 0.09). PE were few, but significantly over-represented in both the Factor V Leiden and prothrombin gene G20210A mutated patients (p = 0.03 and p = 0.05, respectively). However, since 90% of the patients with these genetic risk factors will not suffer a VTE event, a general pre-operative genotyping is, in our opinion, of questionable value.


Assuntos
Resistência à Proteína C Ativada/complicações , Artroplastia de Quadril , Artroplastia do Joelho , Fator V/genética , Glicina/análogos & derivados , Complicações Pós-Operatórias/epidemiologia , Protrombina/genética , Trombofilia/complicações , Trombose Venosa/epidemiologia , Resistência à Proteína C Ativada/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Azetidinas/uso terapêutico , Benzilaminas , Análise Mutacional de DNA , Dalteparina/uso terapêutico , Método Duplo-Cego , Europa (Continente)/epidemiologia , Feminino , Predisposição Genética para Doença , Genótipo , Glicina/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/prevenção & controle , Regiões Promotoras Genéticas/genética , Estudos Prospectivos , Embolia Pulmonar/epidemiologia , Embolia Pulmonar/etiologia , Embolia Pulmonar/genética , Embolia Pulmonar/prevenção & controle , Fatores de Risco , Trombofilia/genética , Trombose Venosa/etiologia , Trombose Venosa/genética , Trombose Venosa/prevenção & controle
16.
Thromb Res ; 101(6): 477-82, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11323005

RESUMO

Oral thrombin inhibitors are under development as potential drugs for prophylaxis and treatment of thrombotic events. The effect of pretreatment with two direct thrombin inhibitors, melagatran and inogatran, was evaluated in a rat model of cerebral infarction. Ischaemic stroke was induced by photochemical reaction after an injection of Rose Bengal and focused posterior and to the right of the intersection of the coronal and sagittal sutures on the intact calvarium. A single oral dose of melagatran (30 micromol/kg) significantly reduced the volume of the cortical infarct by 53% (P<.05) compared with control. In addition, following intravenous inogatran (6 micromol/kg) or oral inogatran (100 micromol/kg), the volume of the cortical infarct decreased by 83% and 19%, respectively, compared with control. This study showed that experimental focal ischaemic infarction, elicited by photochemically induced endothelial cell damage, can be significantly reduced with melagatran and inogatran, direct thrombin inhibitors.


Assuntos
Antitrombinas/farmacologia , Infarto Encefálico/tratamento farmacológico , Infarto Encefálico/etiologia , Luz/efeitos adversos , Administração Oral , Animais , Antitrombinas/administração & dosagem , Azetidinas , Benzilaminas , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/patologia , Córtex Cerebral/efeitos da radiação , Avaliação Pré-Clínica de Medicamentos , Glicina/administração & dosagem , Glicina/análogos & derivados , Glicina/farmacologia , Hipertensão/complicações , Injeções Intravenosas , Masculino , Fotoquímica , Piperidinas/administração & dosagem , Piperidinas/farmacologia , Ratos , Ratos Endogâmicos SHR
17.
Thromb Res ; 101(3): 145-57, 2001 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11228338

RESUMO

UNLABELLED: Melagatran is the active form of the oral, direct thrombin inhibitor H 376/95. In several animal models of thrombosis, the antithrombotic properties of melagatran have been demonstrated, without any increase in experimental bleeding. However, as with all anticoagulants, in emergency situations, reversal of the anticoagulation may be necessary. In this study, increasing doses of activated prothrombin complex concentrate (APCC, Feiba) or recombinant factor VIIa (r-F VIIa, NovoSeven) were superimposed on high doses of melagatran, or saline, in anaesthetised rats. The haemostatic effect was evaluated in two bleeding time models and a potential prothrombotic effect was evaluated in an arterial thrombosis model. Compared with melagatran alone (0.5 micromol/kg/h), Feiba in doses of > or =25 U/kg significantly shortened the prolonged bleeding time and reduced blood loss. In addition, Feiba > or =50 U/kg when added to melagatran (2 micromol/kg/h), significantly reduced bleeding time. No potentiation of thrombus formation was observed when Feiba was added to melagatran, compared with controls. NovoSeven at high doses (2-10 mg/kg) produced a nonsignificant trend in reduction of blood loss and with the highest dose (10 mg/kg) producing only a mild nonsignificant reduction in bleeding time. The prolonged prothrombin time (PT) and the ecarin clotting time (ECT) were more effectively shortened by Feiba than by NovoSeven. In contrast, whole blood clotting time (WBCT) was more effectively shortened by NovoSeven than by Feiba. Activated partial thromboplastin time (APTT) was shortened by NovoSeven but was prolonged by Feiba. Thrombin-antithrombin (TAT) complex formation was increased in a dose-dependent fashion more effectively by Feiba than by NovoSeven. CONCLUSION: Feiba (APCC) reversed prolonged bleeding time and blood loss in rats treated with high doses of melagatran and compared with the control group thrombus formation was not potentiated. NovoSeven (r-F VIIa) at high doses had less pronounced effects on blood loss and bleeding times compared with Feiba.


Assuntos
Anticoagulantes/farmacologia , Fatores de Coagulação Sanguínea/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Fator VII/farmacologia , Glicina/farmacologia , Proteínas Recombinantes/farmacologia , Animais , Azetidinas , Benzilaminas , Tempo de Sangramento , Interações Medicamentosas , Fator VIIa , Glicina/análogos & derivados , Masculino , Ratos , Ratos Sprague-Dawley , Trombose/tratamento farmacológico , Trombose/fisiopatologia
18.
Thromb Res ; 101(3): 159-70, 2001 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11228339

RESUMO

Melagatran is the active form of the oral, direct thrombin inhibitor, H 376/95, that is under evaluation in clinical trials for the prevention and treatment of thromboembolism. In this study, a single dose, calculated on body weight basis, of antifibrinolytic treatment, factor VIIa, factor VIII with and without von Willebrand factor (vWF), factor IX, activated (APCC) or nonactivated (PCC) prothrombin complex concentrates was given intravenously to rats and rabbits, in an attempt to reverse the prolonged bleeding time during intensive anticoagulation with melagatran (2 micromol/kg/h). The doses used were at or above human therapeutic doses. The cutaneous tail bleeding time in the rat, as well as the ear incision bleeding time and cuticle bleeding time, and the blood loss in the rabbit were used for evaluation of the hemostatic effects of these agents. In vivo Feiba (APCC) and Prothromplex-T (PCC) shortened the prolonged cutaneous bleeding times in rats (P<.05); Feiba and Autoplex (APCC) shortened the cutaneous bleeding times in rabbits (P<.05). In contrast, Prothromplex-T prolonged bleeding times and blood loss in the rabbits (P<.05). Ex vivo Feiba, Autoplex and NovoSeven (rF VIIa) significantly (P<.05) shortened the prolonged whole blood clotting time (WBCT). Prothromplex-T significantly prolonged WBCT, activated clotting time (ACT) and activated partial thromboplastin time (APTT). Feiba, Autoplex, and Prothromplex-T increased thrombin generation measured as increased thrombin-antithrombin complex (TAT) formation. In conclusion, APCCs were found to be the most effective agents for reversing bleeding time induced by a very high plasma concentration of melagatran. APCC and recombinant activated factor FVII (rF VIIa) effectively shortened the prolonged WBCT. Thus, stimulating thrombin generation with the use of APCC may counteract the anticoagulant effect observed with a very high dose of a thrombin inhibitor.


Assuntos
Anticoagulantes/farmacologia , Tempo de Sangramento , Glicina/farmacologia , Hemorragia/tratamento farmacológico , Animais , Anticoagulantes/uso terapêutico , Azetidinas , Benzilaminas , Fatores de Coagulação Sanguínea/farmacologia , Fatores de Coagulação Sanguínea/uso terapêutico , Fator IX/farmacologia , Fator IX/uso terapêutico , Fator VIII/farmacologia , Fator VIII/uso terapêutico , Fator VIIa/farmacologia , Fator VIIa/uso terapêutico , Glicina/análogos & derivados , Glicina/uso terapêutico , Humanos , Coelhos , Ratos , Trombina/antagonistas & inibidores , Fator de von Willebrand/farmacologia , Fator de von Willebrand/uso terapêutico
19.
Thromb Res ; 101(3): 171-81, 2001 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11228340

RESUMO

UNLABELLED: Suboptimal gastrointestinal absorption is a problem for many direct thrombin inhibitors. The studies presented herein describe the new oral direct thrombin inhibitor H 376/95, a prodrug with two protecting residues added to the direct thrombin inhibitor melagatran. Absorption properties in vitro: H 376/95 is uncharged at intestinal pH while melagatran is charged. H 376/95 is 170 times more lipophilic (octanol water partition coefficient) than melagatran. As a result, the permeability coefficient across cultured epithelial Caco-2 cells is 80 times higher for H 376/95 than for melagtran. Pharmacokinetic studies in healthy volunteers: H 376/95 is converted to melagatran in man. Oral bioavailability, measured as melagatran in plasma, is about 20% after oral administration of H 376/95, which is 2.7-5.5 times higher than after oral administration of melagatran. The variability in the area under the drug plasma concentration vs. time curve (AUC) is much smaller with oral H 376/95 (coefficient of variation 20%) than with oral melagatran (coefficient of variation 38%). Pharmacodynamic properties: H 376/95 is inactive towards human alpha-thrombin compared with melagatran [inhibition constant (K(i)) ratio, 185 times], a potential advantage for patients with silent gastrointestinal bleeding. In an experimental thrombosis model in the rat, oral H 376/95 was more effective than the subcutaneous low molecular weight heparin dalteparin in preventing thrombosis. CONCLUSION: By the use of the prodrug principle, H 376/95 endows the direct thrombin inhibitor melagatran with pharmacokinetic properties required for oral administration without compromising the promising pharmacodynamic properties of melagatran.


Assuntos
Anticoagulantes/farmacocinética , Glicina/farmacocinética , Mucosa Intestinal/efeitos dos fármacos , Administração Oral , Anticoagulantes/administração & dosagem , Azetidinas/administração & dosagem , Azetidinas/farmacocinética , Benzilaminas , Células CACO-2 , Glicina/administração & dosagem , Glicina/análogos & derivados , Humanos , Absorção Intestinal , Mucosa Intestinal/metabolismo , Masculino , Pró-Fármacos/administração & dosagem , Pró-Fármacos/farmacocinética , Trombina/antagonistas & inibidores
20.
Phys Rev Lett ; 86(3): 516-9, 2001 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-11177869

RESUMO

We consider a magnetic S = 1/2 impurity in the antiferromagnetic spin chain as a function of two coupling parameters: the symmetric coupling of the impurity to two sites in the chain J1 and the coupling between the two sites J2. By using field theory arguments and numerical calculations we can identify all possible fixed points and classify the renormalization flow between them, which leads to a nontrivial phase diagram. Depending on the detailed choice of the two (frustrating) coupling strengths, the stable phases correspond either to a decoupled spin with Curie law behavior or to a non-Fermi-liquid fixed point with a logarithmically diverging impurity susceptibility as in the two-channel Kondo effect. Our results resolve a controversy about the renormalization flow.

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