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1.
Health Aff (Millwood) ; 38(9): 1420-1424, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31479361

RESUMO

A new model moves high-need patients out of the emergency department and into a rich network of social supports.


Assuntos
Acessibilidade aos Serviços de Saúde , Pessoas sem Cobertura de Seguro de Saúde , Melhoria de Qualidade , Provedores de Redes de Segurança/normas , População Urbana , Tennessee
2.
Health Aff (Millwood) ; 38(1): 8-13, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30615533

RESUMO

In Maryland communities such as Annapolis, Health Enterprise Zones have spurred investment and experimentation in care delivery.


Assuntos
Atenção à Saúde/organização & administração , Recursos em Saúde/organização & administração , Acessibilidade aos Serviços de Saúde , Atenção Primária à Saúde/organização & administração , Populações Vulneráveis , Humanos , Maryland
3.
Cardiovasc Res ; 28(8): 1226-30, 1994 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7954625

RESUMO

OBJECTIVE: The aim was to determine if neutrophils are activated and sequestered as they pass through postischaemic human myocardium. METHODS: The occurrence of neutrophil activation during the reperfusion of the ischaemic myocardium was investigated in 16 selected patients undergoing coronary artery bypass surgery. Neutrophils were counted and elastase and lactoferrin released into the plasma were measured simultaneously in myocardial venous blood and in peripheral venous blood, before aortic cross clamping (T0), and two (T1), 10 (T2), and 20 (T3) min after unclamping. RESULTS: At T0, no statistically significant difference was noted between peripheral and myocardial blood with respect to the three variables studied. Reperfusion was associated with a significantly lower neutrophil count in myocardial blood compared to peripheral blood (p < 0.001), suggesting that neutrophils were trapped within the myocardium during reperfusion. In addition, levels of elastase (T1, T2, and T3), and lactoferrin (T1) were significantly higher in myocardial blood as compared to peripheral blood (p < 0.001), suggesting that activated neutrophils released their granular content into the plasma milieu. CONCLUSION: We provide evidence consistent with local neutrophil activation during myocardial reperfusion in patients undergoing coronary artery bypass surgery, in addition to the well described systemic activation related to cardiopulmonary bypass.


Assuntos
Ponte de Artéria Coronária , Isquemia Miocárdica/imunologia , Reperfusão Miocárdica , Miocárdio/imunologia , Neutrófilos/imunologia , Adulto , Idoso , Circulação Coronária , Feminino , Humanos , Lactoferrina/sangue , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/sangue , Elastase Pancreática/sangue , Estudos Prospectivos
4.
Atherosclerosis ; 71(1): 71-6, 1988 May.
Artigo em Inglês | MEDLINE | ID: mdl-3377881

RESUMO

Associations of plasma testosterone and estradiol with some haemostatic factors (factor VII activity, fibrinogen, antithrombin III and alpha 2-antiplasmin) were cross-sectionally examined in 251 healthy, middle-aged men participating in the Paris Prospective Study II on risk factors for ischaemic heart disease. Testosterone levels were negatively correlated to factor VII activity and alpha 2-antiplasmin, the main inhibitor of fibrinolysis. No association was found either between testosterone levels and both fibrinogen and antithrombin III, or between estradiol levels and the set of haemostatic variables. The associations between testosterone and both factor VIIc and alpha 2-antiplasmin were independent of HDL-cholesterol, LDL-cholesterol, triglycerides, smoking, alcohol, body mass index and blood pressure. These results suggest that low circulating testosterone levels might be associated with a hypercoagulability state and therefore could contribute to an increased risk of IHD.


Assuntos
Antígenos/metabolismo , Antitrombina III/metabolismo , Estradiol/sangue , Fator VII/imunologia , Fibrinogênio/metabolismo , Testosterona/sangue , alfa 2-Antiplasmina/metabolismo , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Doença das Coronárias/etiologia , Fator VII/metabolismo , França , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Triglicerídeos/sangue
5.
Atherosclerosis ; 119(1): 119-27, 1996 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-8929253

RESUMO

This paper describes the relationship of factor VII coagulant activity (FVIIc), FVII Arg/Gln353 genotype and risk of myocardial infarction (MI) in the ECTIM (Etude Cas Témoin sur l'Infarctus du Myocarde) study, a multi-centre case-control study on MI. FVIIc was significantly higher in controls from all four centres: Belfast, Lille, Strasbourg and Toulouse, perhaps because elevated FVIIc may predispose to fatal rather than non-fatal MI. Major influences on FVIIc were FVII Arg/Gln353 genotype, triglyceride and cholesterol levels. There was no significant effect of genotype on MI risk however there was a non-significant trend towards increased MI risk in FVII Arg353 homozygotes. Confirming previous observations, FVIIc was highest in FVII Arg353 homozygotes, intermediate in heterozygotes and lowest in FVII Gln353 homozygotes (except Toulouse cases) these differences being highly statistically significant (except Strasbourg cases P = 0.1). In Belfast, consistent with previous findings, there was significant interaction between FVII Arg/Gln353 genotype and triglyceride level in determining FVIIc, whilst this was absent in the French centres. In conclusion, FVII Arg/Gln353 genotype strongly determines FVIIc although neither factor has a strong impact on MI risk in the ECTIM study.


Assuntos
Fator VII/genética , Infarto do Miocárdio/sangue , Adulto , Coagulação Sanguínea , Estudos de Casos e Controles , Fator VII/metabolismo , França/epidemiologia , Humanos , Irlanda/epidemiologia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/genética , Polimorfismo Genético , Fatores de Risco
6.
Thromb Haemost ; 71(4): 434-40, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8052959

RESUMO

To assess the role of genetic and environmental factors in the predisposition to atherosclerosis, 682 students whose father had suffered a myocardial infarction before the age of 55 ("cases") and 1312 controls matched for age and sex, were recruited from 14 Universities in Europe. Fibrinogen, factor VIIc and PAI-1 were compared between cases and controls across European regions. Fibrinogen and factor VIIc were positively correlated with BMI, smoking and contraception. PAI-1 was positively and independently correlated with BMI and waist-to-hip ratio, and negatively with contraception. Factor VIIc and PAI-1 were correlated with cholesterol and triglycerides, and fibrinogen was weakly correlated with LDL-cholesterol. After adjustment for covariates and lipids, fibrinogen level was significantly higher in male cases than in controls (2.38 vs 2.29, p < 0.01). No such difference was found in females (2.59 vs 2.57 - NS). There was no significant case/control difference for factor VIIc and PAI-1. These results support the hypothesis that fibrinogen is a transmissible risk factor of coronary artery disease in males. No such evidence was provided for factor VIIc and PAI-1.


Assuntos
Pai , Fibrinogênio/análise , Infarto do Miocárdio/genética , Adolescente , Adulto , Consumo de Bebidas Alcoólicas , Antígenos/análise , Constituição Corporal , Índice de Massa Corporal , Estudos de Casos e Controles , Anticoncepção , Suscetibilidade a Doenças , Europa (Continente)/epidemiologia , Fator VII/análise , Feminino , Humanos , Lipídeos/sangue , Masculino , Infarto do Miocárdio/sangue , Infarto do Miocárdio/epidemiologia , Inibidor 1 de Ativador de Plasminogênio/análise , Fatores de Risco , Fumar
7.
Thromb Haemost ; 70(4): 584-7, 1993 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-8115983

RESUMO

Large cohort studies have shown that postmenopausal estrogen use was associated with a reduction in the risk of coronary heart disease. This putative beneficial effect of hormone replacement therapy (HRT) may be partly mediated through changes in clotting factors and fibrinolytic system. We have measured haemostatic variables in 293 consecutive healthy women aged 45-54 years who attended a health check-up centre in Paris (IPC). Premenopausal women taking hormonal therapy were excluded (n = 34). Most women using HRT were given 17-beta estradiol in combination with progestin. Mean levels (m +/- sd) of plasma fibrinogen, factor VII coagulant activity and plasminogen activator inhibitor (PAI) were significantly higher in postmenopausal women not taking HRT (n = 99) than in premenopausal women (n = 139) within the same decade (319 +/- 52 mg/dl vs 304 +/- 60 mg/dl, 107 +/- 17% vs 96 +/- 16%, 9.73 +/- 5.71 U/ml vs 7.61 +/- 4.36 U/ml respectively). Allowance for main cardiovascular risk factors made no substantial differences to the results, although the effect of the menopause on fibrinogen was no longer significant. HRT (n = 21) significantly reversed the menopause-related changes in factor VII (94 +/- 15%), even after adjustment for confounding factors. The same trend in both fibrinogen (294 +/- 46 mg/dl) and PAI (8.22 +/- 5.51 U/ml) was observed. Similar results were found in women using oral or percutaneous estrogen. Our findings suggest that 17-beta estradiol in combination with progestins may protect against an increased thrombotic tendency in postmenopausal women. Randomized clinical trials are urgently needed for a better understanding of HRT effect on atherothrombotic process.


Assuntos
Estradiol/uso terapêutico , Terapia de Reposição de Estrogênios , Hemostasia/efeitos dos fármacos , Menopausa/sangue , Doença das Coronárias/prevenção & controle , Feminino , Humanos , Menopausa/efeitos dos fármacos , Pessoa de Meia-Idade , Fatores de Risco
8.
Thromb Haemost ; 74(3): 928-32, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8571323

RESUMO

Several studies have suggested a dose-response relation between the oestrogen content of oral contraceptive (OC) and the risk of both venous thrombosis and arterial disease, when oestrogen doses were higher than 50 micrograms. However, there is no clear epidemiological evidence for a decrease in thrombotic risk with formulations containing less than 50 micrograms oestrogen. Therefore, we investigated haemostatic variables in users of OC containing either 30 micrograms (35 women) or 50 micrograms (29 women) ethinyl estradiol as compared with non users (64 women) matched for age and smoking status. Mean values of antithrombin activity were significantly lower in 30 micrograms or 50 micrograms oestrogen users than in non users (96% and 98% vs 105%, respectively, p < 0.001), but they were not significantly different between the two groups of OC users. There was a significant increase in mean values of factor VII antigen in women taking either 30 micrograms or 50 micrograms oestrogen as compared with non users (96% and 101% vs 85%, respectively, p < 0.005). Although the difference between both groups of OC users was not significant, a positive linear trend in factor VII levels was observed within the 0-50 micrograms oestrogen range (p < 0.001). Mean levels of fibrinogen were slightly higher in 30 micrograms or 50 micrograms oestrogen users than in non users (2.71, 2.66 g/l vs 2.55 g/l, respectively), but there was no significant difference between the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)


PIP: In Paris, France, clinicians compared data on 64 women aged 19-40 who used combined oral contraceptives (OCs) for 6-200 months with data on 64 healthy women who did not use OCs for the last two months and who were matched for age and smoking status to investigate activity of plasminogen activator inhibitor 1 (PAI-1), factor VII antigen, fibrinogen concentration, and antithrombin activity in users of OCs containing either 30 mcg or 50 mcg estrogen and in nonusers. OC users exhibited lower mean values of PAI-1 activity than nonusers (4.63-4.89 vs. 6.47 AU/ml; p 0.02). There was no dose-dependent effect of estrogen on PAI-1 activity, however. Antithrombin activity values were much lower in OC users than nonusers (96-98% vs. 105%; p 0.001). The difference between the two groups of OC users was not significant, however. The mean values of factor VII antigen in women using either 30 mcg or 50 mcg estrogen were higher than those for nonusers (96% and 101% vs. 85%, respectively; p 0.005). The difference in factor VII antigen values between the two OC groups was not significant, yet there was a positive linear trend in factor VII levels within the 0-50 mcg estrogen range (p 0.001). No significant difference in the mean fibrinogen levels between the three groups (30 mcg estrogen OC group, 50 mcg estrogen OC group, and nonusers) was observed. Hemostatic variables were not significantly different between 30 mcg estrogen OCs containing 100 mcg, 150 mcg, or 200 mcg levonorgestrel. The researchers could not conduct a valid assessment of the progestogen effect in 50 mcg estrogen OCs due to the wide range of different types of progestogens. These findings suggest an alteration of blood coagulation and fibrinolysis in OC users within the 30-50 mcg estrogen range. Estrogen appears to have a dose-dependent effect on factor VII but no significant effect on PAI-1 activity and other markers of thrombogenic risk and arterial disease risk.


Assuntos
Anticoncepcionais Orais Combinados/efeitos adversos , Anticoncepcionais Orais Hormonais/efeitos adversos , Estrogênios/efeitos adversos , Hemostasia/efeitos dos fármacos , Inibidor 1 de Ativador de Plasminogênio/sangue , Adulto , Antígenos/sangue , Antitrombina III/metabolismo , Estudos de Casos e Controles , Relação Dose-Resposta a Droga , Fator VII/imunologia , Feminino , Fibrinogênio/metabolismo , Humanos , Fatores de Risco
9.
Thromb Haemost ; 60(1): 75-8, 1988 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-3187948

RESUMO

Acid-soluble collagen samples were prepared from individual skins of 24 month old rats (n = 8), 2 month old young controls (n = 8) and from 6 month old streptozotocin-diabetic rats (n = 5) and their age-matched controls (n = 10). Less collagen was obtained by acid extraction and salt precipitations from skins of diabetic and aged rats than from those of their respective controls. The collagen preparations from diabetic and aged rats showed an increased ratio of beta/alpha components. The rate of "in vitro" fibrillogenesis was less for collagen from diabetic rats than from controls. It was not modified for collagens from aged rats. The aggregating potency towards normal human platelets was markedly increased for collagens from aged and diabetic rats: reduced latency time (p less than 0.01) and increased velocity (p less than 0.01) were observed for collagens from aged rats when compared with young rats (16.5 micrograms/ml). Increased velocity (p less than 0.01) was also observed for collagens from diabetic rats (8.25, 11 and 16.5 micrograms/ml), without modification of latency time.


Assuntos
Envelhecimento/fisiologia , Colágeno/fisiologia , Diabetes Mellitus Experimental/fisiopatologia , Agregação Plaquetária , Pele/fisiopatologia , Animais , Diabetes Mellitus Experimental/sangue , Eletroforese em Gel de Poliacrilamida , Humanos , Masculino , Ratos , Ratos Endogâmicos
10.
Thromb Haemost ; 74(3): 837-41, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8571307

RESUMO

We have investigated the interrelationships of plasma PAI-1 activity, the PAI-1 4G/5G polymorphism and risk of myocardial infarction (MI) in the ECTIM study, a case-control study of MI based in Belfast, Lille, Strasbourg and Toulouse. Mean PAI-1 levels in cases were similar across all centres but in controls, levels in the French centres were significantly higher. Only in Belfast were PAIl1 levels higher in cases (11.7 AU/ml) than controls (10.5 AU/ml). The PAI-1 4G allele frequency was similar in cases and controls (0.55 and 0.54). In all groups, 4G homozygotes had the highest mean plasma PAI-1 level (4G4G vs 5G5G; cases overall: 14.2 vs 12.1AU/ml; controls overall: 15.0 vs 12.6AU/ml), with the heterozygotes generally intermediate. The data from Belfast are consistent with the literature implicating PAI-1 level as an MI risk factor. In ECTIM, the PAI-1 4G/5G polymorphism is not a genetic risk factor for MI but is associated with PAI-1 activity. Thus homozygosity for the 4G allele may predispose to elevated PAI-1 and impaired fibrinolysis, perhaps requiring interaction with other genetic or environmental factors to influence MI risk.


Assuntos
Infarto do Miocárdio/sangue , Inibidor 1 de Ativador de Plasminogênio/genética , Polimorfismo Genético , Regiões Promotoras Genéticas , Adulto , Alelos , Sequência de Bases , Estudos de Casos e Controles , França/epidemiologia , Genótipo , Heterozigoto , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/genética , Irlanda do Norte/epidemiologia , Inibidor 1 de Ativador de Plasminogênio/sangue , Fatores de Risco , Organização Mundial da Saúde
11.
Thromb Haemost ; 79(2): 359-61, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9493591

RESUMO

The histidin-rich glycoprotein (HRG) may contribute to coronary heart disease as a consequence of its possible thrombophilic properties. To test this hypothesis we have investigated the Pro186/Ser polymorphism of the HRG gene, which is known to strongly affect plasma HRG levels, in a large multicenter case-control study of myocardial infarction (MI). The results failed to demonstrate any association between the polymorphism and MI or angiographically assessed coronary stenosis.


Assuntos
Infarto do Miocárdio/genética , Proteínas/genética , Adulto , Alelos , Proteínas Sanguíneas/genética , Estudos de Casos e Controles , Glicoproteínas/genética , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético
12.
Drugs ; 52 Suppl 7: 8-14; discussion 14-5, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9042555

RESUMO

Studies on the pharmacological and pharmacodynamic properties of heparins are complicated by the heterogeneity of heparin preparations. It is important to consider the molecular weight distribution, which may differ from one preparation to another. Molecules with a molecular weight ranging from about 2000 to 5000D are abundant in low molecular weight heparins (LMWHs), while they are present at a very low concentration in standard heparin. The clinical relevance of this difference is not fully understood. Recent work from our laboratory demonstrates that factor VII activation to factor VIIa in vitro is significantly inhibited by heparins. This is another aspect of some importance in understanding the mechanism of action of heparins. The bioavailability and plasma clearance of anti-Xa activity are well documented. In contrast, clear results regarding the bioavailability of anti-IIa activity are still missing. Recent data indicate that the anti-Xa activity of different molecules of heparin does not increase in parallel with the molecular weight of the heparin chain. In contrast, the anti-IIa activity of different molecules of heparin increases in parallel with the molecular weight. This could explain why activated partial-thromboplastin time is less prolonged with LMWHs than with standard heparin. There is growing evidence that anti-Xa activity contributes to the antithrombotic effect of heparins, although it is generally accepted that anti-IIa activity plays a major role. There have been 3 important findings from recent work on the pharmacology of heparins: i) heparin at a very low dose has thrombopoietic activity; ii) in hip surgery, the incidence of heparin-induced thrombocytopenia is significantly lower in patients receiving subcutaneous LMWHs for 2 weeks compared with patients receiving unfractionated heparin; and iii) the risk of osteoporosis with long term treatment with LMWHs seems lower than with standard heparin.


Assuntos
Anticoagulantes/farmacologia , Heparina de Baixo Peso Molecular/farmacologia , Heparina/farmacologia , Animais , Anticoagulantes/farmacocinética , Antitrombina III/agonistas , Disponibilidade Biológica , Proteínas Sanguíneas/metabolismo , Hemorragia/induzido quimicamente , Heparina/efeitos adversos , Heparina/farmacocinética , Heparina de Baixo Peso Molecular/efeitos adversos , Heparina de Baixo Peso Molecular/farmacocinética , Humanos , Osteoporose/induzido quimicamente , Ligação Proteica , Trombocitopenia/induzido quimicamente
13.
J Clin Pharmacol ; 28(7): 609-18, 1988 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2851016

RESUMO

The pharmacokinetics of enoxaparine, a low molecular weight heparin, was randomly studied in 12 healthy male volunteers. Doses of 20, 40, 60, and 80 mg were injected subcutaneously in randomized cross-over fashion. Anti-IIa and anti-Xa activities (using amidolytic methods), and calcium thrombin time, were measured over 36 hours. The maximum Amax of the anti-IIa and anti-Xa activities appeared 3 to 4 hours after administration. The terminal half-lives of anti-IIa and anti-Xa activities were approximately 2 and 4 hours, respectively, with no significant variation between the different doses. For the anti-Xa activity, there was a highly significant positive correlation between the dose injected and individual values of Amax (r = +0.915; P less than .001) and AUC (r = +0.913; P less than .001). Enoxaparine displays a relatively small apparent volume of distribution (about 7.0 L) and its total body clearance is about 1.25 L/hr. The mean residence time ranges from 4.6 to 7.6 hours. Thus, the pharmacokinetic profile of enoxaparine is characterized by a linear relationship between dose and absorption, a relatively low clearance and long elimination half-life, and a high anti-Xa/anti-IIa ratio.


Assuntos
Heparina de Baixo Peso Molecular/farmacologia , Adulto , Antitrombina III/metabolismo , Meia-Vida , Heparina de Baixo Peso Molecular/administração & dosagem , Heparina de Baixo Peso Molecular/farmacocinética , Humanos , Injeções Subcutâneas , Masculino
14.
Thromb Res ; 57(4): 585-92, 1990 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-2158152

RESUMO

The Heptest heparin assay has recently been introduced, and evaluated for the laboratory monitoring of patients receiving low molecular weight heparins (LMWH). The aim of the present study was to elucidate the relative role on the Heptest assay of the anti-factors Xa and IIa activities present in the three types of compounds that possess: 1. exclusively anti-Xa activity (LF1: LMWH fractions with MW ranging from 1,200 to 4,200 D.); 2. both anti-Xa and anti-IIa activities (LF2 with MW from 4,800 to 12,000 D.); 3. exclusive anti-IIa activity (Hirudin and Dermatan Sulfate). All compounds studied demonstrated dose-dependent activities in both amidolytic and clotting assays. The LF2 in contrast to the LF1, additionally enhanced the clotting times of Heptest. This enhancement was shown to be due to the anti-Factor IIa activity of the agents. Heptest does not exclusively reflect Anti-Xa activity since it is influenced by agents containing exclusive anti-IIa activity like Hirudin and Dermatan Sulfate. At low concentrations of LF2, Heptest measures predominantly the anti-factor Xa activity while at higher concentrations it is influenced by the combined activity of anti-factor Xa and anti-factor IIa. However, Heptest sensitivity to anti-factor IIa is significantly lower than for anti-Xa activity.


Assuntos
Condroitina/análogos & derivados , Dermatan Sulfato/análise , Inibidores do Fator Xa , Heparina de Baixo Peso Molecular/análise , Hirudinas/análise , Protrombina/antagonistas & inibidores , Dermatan Sulfato/farmacologia , Relação Dose-Resposta a Droga , Heparina de Baixo Peso Molecular/farmacologia , Hirudinas/farmacologia , Humanos , Monitorização Fisiológica , Tempo de Coagulação do Sangue Total
15.
Thromb Res ; 65(4-5): 641-50, 1992 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-1319619

RESUMO

A total of 1290 patients (Pts) undergoing general surgery were enrolled in a randomized, multicentre double-blind study in order to investigate the efficacy and safety of two different doses of a low molecular weight heparin (LMWH) (Logiparin) for the prevention of deep vein thrombosis. Patients were randomized to either 5,000 IU unfractionated heparin twice daily, 2,500 anti-Xa or 3,500 anti-Xa units of Logiparin once daily. Each treatment was given subcutaneously two hours before surgery and continued for seven to ten days. All coagulation tests were performed blindly in a core laboratory. Blood samples were collected before surgery and then 3 hours after injection on Day 3 and 5 after surgery. Anti-Xa amidolytic activities were significantly higher in the two LMW Heparin groups than in the unfractionated heparin group (mean peak levels +/- s.e.m. on Day 3: 0.097 +/- 0.004; 0.152 +/- 0.004 and 0.034 +/- 0.003 IU respectively). As expected a significant correlation was observed between anti-Xa activity and the dose of LMW Heparin injected. The correlation coefficient was higher when the doses were expressed in anti-Xa units/kg body weight. However, the body weight accounts for only 16% of the interindividual variability of anti-Xa activity. Therefore, there is no clear evidence to suggest that weight-adjusted doses should be recommended when this LMW Heparin is used as prophylactic treatment in general surgery. A weak negative correlation was found between anti-Xa activity and thrombosis as demonstrated by a positive radiolabelled fibrinogen uptake test and confirmed by positive phlebography. No significant correlation was demonstrated between anti-Xa activity and the occurrence of postoperative bleeding.


Assuntos
Inibidores do Fator Xa , Hemorragia/prevenção & controle , Heparina de Baixo Peso Molecular/farmacologia , Heparina/farmacologia , Trombose/prevenção & controle , Peso Corporal , Método Duplo-Cego , Esquema de Medicação , Fator VII/análise , Fator VII/antagonistas & inibidores , Feminino , Humanos , Lipoproteínas/análise , Masculino , Período Pós-Operatório , Tromboplastina/análise , Tromboplastina/antagonistas & inibidores
16.
Thromb Res ; 68(2): 167-74, 1992 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-1475779

RESUMO

The in vitro anticoagulant activity of recombinant desulphated hirudin (HBW 023) and its antithrombotic activity in a rabbit venous stasis model were assessed in comparison to unfractionated heparin (UH). The specific activity of r-hirudin in rabbit plasma is similar to that of unfractionated heparin on a weight basis when using the whole blood clotting time or APTT, while it was five times more potent according to the thrombin clotting time (TCT). Forty-eight (6x8) anaesthetized New Zealand male rabbits were randomized to receive HBW 023 (12.5, 25, 50, 100, 200, 400 micrograms.kg-1), standard heparin (90 micrograms.kg-1) or placebo. Five minutes after administration of the drug, the experimental thrombosis was induced by an injection of glass activated overnight human serum into the marginal vein of the ear and ligation of the jugular vein (Wessler model). The jugular vein was removed after 10 min stasis and examined by a researcher unaware of the treatment administered. In the Wessler stasis model the fresh thrombus weight and a score as well as the circulating level of r-hirudin using a chromogenic substrate assay were used to determine the inhibitory effect of the drug. Highly significant inverse correlations were found between fresh thrombus weight and the injected doses as well as r-hirudin plasma levels. The ID50 which was the dose of the drug that induced a complete inhibition of thrombosis in 50% of the dose group tests was about 200 micrograms.kg-1.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Hemostasia , Heparina/farmacologia , Hirudinas/farmacologia , Animais , Constrição , Modelos Animais de Doenças , Técnicas In Vitro , Veias Jugulares , Masculino , Coelhos , Distribuição Aleatória , Proteínas Recombinantes/farmacologia
17.
Thromb Res ; 28(1): 37-46, 1982 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-7157229

RESUMO

In previous papers, we have described the preparation and heparin-like properties of insoluble modified polystyrene resins. We now report results about the interactions of several coagulation factors with some of these materials. Most of the non-activated factors are neither adsorbed nor modified, except factor V and prekallikrein. In contrast thrombin, antithrombin III and factor Xa adsorb on the surface of such insoluble polymers. Thrombin can be desorbed by addition of a polycationic compound. The inactivation of thrombin or factor Xa by antithrombin is catalysed by the presence in the mixture of these insoluble materials as it is with soluble heparin. The initial velocity of these reactions is second order for both types of catalysis-homogeneous or heterogeneous - as previously reported for soluble heparin. In the case of these insoluble materials, the inhibition of protease by antiprotease seems to be accelerated when complexes are formed between the polymer and the proteins.


Assuntos
Anticoagulantes , Fatores de Coagulação Sanguínea , Poliestirenos/farmacologia , Resinas Sintéticas/farmacologia , Adsorção , Humanos , Técnicas In Vitro , Cinética
18.
Thromb Res ; 58(5): 445-54, 1990 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-2164262

RESUMO

The effect of different heparins and a synthetic pentasaccharide on the inhibition of intrinsic prothrombinase and of its generation was studied by a new technique, using a defibrinated prothrombin poor human plasma, supplemented with phospholipids and calcium. Prothrombinase activity was evaluated on purified prothrombin with a chromogenic substrate. This technique is designed to bypass the interference of massive endogenous thrombin generation on the measurement of prothrombinase activity. We first validated the specificity of the technique by using specific Xa and IIa inhibitors. Then, the inhibition of prothrombinase generation and the inhibition of generated prothrombinase were both studied. The results showed that anti-Xa activity measured on exogenous bovine factor Xa added to plasma was not correlated with the inhibition of prothrombinase generation or prothrombinase activity. The concentrations required for unfractionated heparin (the 4th International Standard: 4th IS UH), 1st International Standard Low Molecular Weight Heparins (1st IS LMWH), enoxaparin, Fraxiparine, and pentasaccharide in order to inhibit preformed prothrombinase were significantly higher than those necessary to inhibit prothrombinase generation. These data suggest that anti-Xa activity of unfractionated heparin and its derivatives does not completely reflect the extent of the inhibition of intrinsic prothrombinase generation by UH, LMWH, and pentasaccharide. On the other hand, anti-IIa activity of heparins could be responsible for the inhibition of prothrombinase generation. The action of pentasaccharide devoid of anti-IIa activity on prothrombinase generation appears related to its indirect effect on the formation of initial thrombin traces. This new technique provides a tool to study the essential role played by thrombin during the early steps of coagulation.


Assuntos
Heparina/farmacologia , Protrombina/metabolismo , Tromboplastina/antagonistas & inibidores , Inibidores do Fator Xa , Heparina de Baixo Peso Molecular/farmacologia , Humanos , Hipoprotrombinemias/sangue , Técnicas In Vitro , Oligossacarídeos/farmacologia , Protrombina/antagonistas & inibidores , Trombina/metabolismo
19.
Thromb Res ; 75(5): 577-80, 1994 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-7992258

RESUMO

Tissue Factor Pathway Inhibitor (TFPI), is known, to be released in plasma after injection of intravenous or subcutaneous injection of heparin or low molecular weight heparin (1,2). Addition of protamine or polybrene in plasma can neutralize anticoagulant effects of heparin in vitro but not completely ex vivo in patients treated with heparin (3). It was believed for many years that this post-heparin anticoagulant effect was due to another activity released by heparin. More recently it has been shown that post-heparin anticoagulant effect could be inhibited by anti-TFPI antibodies (4). Since we have shown in a previous work (5), that in healthy volunteers, pharmacokinetics of TFPI were more closely related to anti IIa activity than anti Xa activity we hypothesized that fragments with anti-IIa activity may be required for this release, possibly from vascular wall. In order to determine if a very low molecular weight glycosaminoglycan can release TFPI in plasma, in the present study, we compared plasma TFPI amidolytic activity after intravenous injection in rabbits of pentasaccharide (PS), a synthetic fragment of very low molecular weight and with a strong and exclusive anti Xa activity, and unfractionated heparin (UFH).


Assuntos
Fibrinolíticos/sangue , Heparina/farmacologia , Lipoproteínas/sangue , Oligossacarídeos/farmacologia , Animais , Fibrinolíticos/farmacocinética , Heparina/administração & dosagem , Heparina de Baixo Peso Molecular/administração & dosagem , Heparina de Baixo Peso Molecular/farmacologia , Injeções Intravenosas , Lipoproteínas/farmacocinética , Masculino , Oligossacarídeos/administração & dosagem , Coelhos
20.
Thromb Res ; 70(3): 275-80, 1993 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-8327993

RESUMO

PIP: The relation between oral contraceptive (OC) use and changes in factor VII activation using standard factor VII clotting test and enzyme-linked immunosorbent assay (ELISA) for the quantification of antigen factor VII (factor YIIag) in view of the increased risk of thromboembolism in OC users was studied. 30 healthy women using OC and 30 women matched for age and smoking status were recruited from a health check-up center in Paris. The combined OC contained 50 mcg of ethinyl estradiol with any progestogen. Controls had not taken any hormonal therapy for the 2 previous months. The mean duration of OC use was 50 months with a range of 6-204 months. Fasting venous blood (9 volumes) was collected during the menstrual cycle into siliconized vacutainer tubes containing 3.2% trisodium citrate (1 volume). Factor VIIc was assayed using a human factor VII-deficient plasma. Factor VIIag was measured by ELISA using a commercial kit (Diagnostic Stago, France). The activity of factor VII was assessed by calculating the ratio of factor VIIc to factor VIIag. Serum cholesterol and triglyceride concentrations were determined by enzymatic methods using automated procedure and reagents from Boehringer Mannheim. There was a significant difference between the 2 groups only in serum triglyceride concentrations. There was a positive correlation between factor VIIc and factor VIIag in both controls and OC users (r = 0.71 and 0.87, respectively; p 0.0001). Both factor VIIc and factor VIIag levels were positively associated with serum triglyceride concentrations (correlation coefficients ranged from 0.26 (p 0.10) to 0.46 (p 0.05) with the 2 groups). Mean levels of factor VIIc and factor VIIag were significantly higher in OC users than in controls (about 17% and 21%, respectively). The ratio of factor VIIc and factor VIIag was not significantly higher in OC users than in controls. The raised factor VII coagulant activity in OC users failed to provide evidence of an enhanced activation of factor VII relative to OCs.^ieng


Assuntos
Anticoncepcionais Orais Combinados/farmacologia , Fator VII/metabolismo , Fator VIIa/biossíntese , Tromboembolia/induzido quimicamente , Adulto , Antígenos/análise , Pressão Sanguínea , Índice de Massa Corporal , Anticoncepcionais Orais Combinados/efeitos adversos , Ativação Enzimática/efeitos dos fármacos , Fator VII/análise , Feminino , Humanos , Lipídeos/sangue , Tromboembolia/sangue
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