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1.
Thromb Haemost ; 55(1): 58-60, 1986 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-3085265

RESUMO

Factor VIII coagulant activity (VIII:C) has been shown by several investigators to exhibit increased stability in vitro when physiological levels of plasma ionized calcium are maintained by anticoagulation with heparin rather than citrate. An increase in initial activity of VIII:C in heparin over that of VIII:C in citrate has been reported but this has not been confirmed. In order to assay VIII:C in heparinized plasma, the heparin anticoagulant effect must be excluded without interfering with the validity of the assay. A one-stage clotting assay for VIII:C has been developed where heparin is neutralized by Polybrene, a synthetic polymerized quaternary ammonium salt. VIII:C may be accurately measured by this method which satisfies the requirements for a valid assay of parallelism and linearity.


Assuntos
Fator VIII/análise , Brometo de Hexadimetrina , Testes de Neutralização/métodos , Poliaminas , Heparina/sangue , Humanos
2.
Thromb Haemost ; 73(2): 194-202, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7792729

RESUMO

Individuals with severe factor XI deficiency are prone to excessive bleeding after injury or surgery, but the existence of a haemorrhagic tendency in partial factor XI deficiency is controversial. In this study, 172 members of 30 kindreds (20 non-Jewish) transmitting factor XI deficiency in North West England were interviewed and a bleeding history questionnaire completed. Blood was taken for coagulation assays. The questionnaires were categorised independently by two assessors to determine presence or absence of a bleeding tendency, in the absence of information about the factor XI level or family history. Analysis shows that 48% of heterozygotes have a bleeding tendency. Eighteen (60%) families came to attention because of bleeding problems in heterozygotes. Comparison of histories between partially deficient and non-deficient individuals demonstrated a higher incidence of menstrual problems, an increase in significant bruising, and an increased likelihood of excessive bleeding after tonsillectomy and dental extractions. The incidence of von Willebrand's disease was not increased, but individuals with heterozygous factor XI deficiency who were bleeders tended to have lower levels of factor VIIIc and von Willebrand factor, and were more commonly of blood group 0. These features may contribute to the bleeding tendency. There was no evidence of alteration in factor VII activity (as defined by the ratio of activity to antigen) between the bleeders and non-bleeders. This is convincing evidence for abnormal bleeding in factor XI deficiency which is not confined to severely deficient patients.


Assuntos
Deficiência do Fator XI/genética , Genes Recessivos , Hemorragia/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Tempo de Sangramento , Estudos de Casos e Controles , Criança , Pré-Escolar , Inglaterra , Fator VIII/análise , Feminino , Genótipo , Heterozigoto , História da Medicina , Humanos , Judeus , Masculino , Pessoa de Meia-Idade , Linhagem , Fator de von Willebrand/análise
3.
Thromb Haemost ; 67(3): 314-9, 1992 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-1641821

RESUMO

Factor XI deficiency is an uncommon bleeding disorder usually manifested by excessive bleeding after surgery or trauma. Until recently the only effective therapy has been fresh-frozen plasma (FFP) infusion. We describe the efficacy and safety of a new factor XI concentrate produced from human donor plasma by a modification of the method used for antithrombin III concentrate. The mean recovery of factor XI in the circulation measured on 62 occasions was approximately 91% of the injected dose, and the mean half-disappearance-time was 52 h. The concentrate was used for 31 invasive procedures in 30 patients, including 16 patients who had a definite bleeding tendency on previous occasions, with normal haemostasis being achieved in all but 1. Only 1 patient (previously experiencing allergy to FFP) experienced adverse effects during infusion. Monitoring of liver function tests and viral antibody status in suitable patients has shown no evidence of transmission of hepatitis viruses, HIV-1 or parvovirus B19. We conclude that this concentrate provides effective treatment for patients with factor XI deficiency. Preliminary results suggest safety from virus transmission, but this needs to be established in further studies of previously untreated patients.


Assuntos
Fator XI/uso terapêutico , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Fator XI/efeitos adversos , Fator XI/isolamento & purificação , Hepatite Viral Humana/transmissão , Humanos , Pessoa de Meia-Idade
4.
J Clin Pathol ; 46(5): 470-3, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8320330

RESUMO

AIMS: To develop a rapid, sensitive, and safe method for the analysis of von Willebrand factor (vWf) multimers in plasma or platelet lysates. METHOD: Analysis of vWf multimers was carried out by sodium dodecyl sulphate-agarose discontinuous gel electrophoresis followed by protein transfer to nitrocellulose membranes by western blotting. Blots were probed using horseradish peroxidase (HRP) conjugated rabbit anti-vWf; visualisation of vWf multimers was achieved using a commercially available enhanced chemi-Luminescence (ECL) kit for detecting HRP labelled antibodies on western blots. RESULTS: Electrophoretic transfer of vWf multimers to nitrocellulose membranes, including the higher molecular weight forms, was achieved satisfactorily and there was good resolution of individual multimer bands and of the triplet sub-band structure. Type II vWD variants were readily identifiable. The use of ECL conferred a high degree of sensitivity to the method and the end result on autoradiography film provided a permanent record which did not fade and which was suitable for scanning densitometry. CONCLUSION: The method for vWf multimer analysis described here is sensitive, simple to carry out, uses minimal amounts of reagents, produces results within 48 hours, and does not require the use of potentially hazardous radioactive materials or carcinogenic enzyme substrates.


Assuntos
Kit de Reagentes para Diagnóstico , Fator de von Willebrand/análise , Autorradiografia , Plaquetas/química , Western Blotting , Eletroforese em Gel de Ágar , Estudos de Avaliação como Assunto , Peroxidase do Rábano Silvestre , Humanos , Técnicas Imunoenzimáticas , Isomerismo , Medições Luminescentes
5.
Thromb Res ; 41(1): 43-56, 1986 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-3961726

RESUMO

This study was carried out to investigate the effects on the activated partial thromboplastin time test (APTT) when heparin in plasma was neutralized with protamine, Polybrene(R), poly-DL-lysine, or heparin neutralizing activity (HNA) extracted from platelets; or removed by means of the anion exchange resins TEAE cellulose or ECTEOLA cellulose. The effect on the APTT of adding the polycations protamine, Polybrene or poly-DL-lysine to citrated plasma was examined. The formation of heparin/polycation complexes was studied by means of their light scattering properties. The low yields of platelet HNA obtained excluded this from practical use as an in vitro heparin antagonist. ECTEOLA cellulose was unable to remove plasma heparin at levels as low as 1 U/ml by the technique employed. TEAE cellulose was able to efficiently remove at least 40 U of heparin from 1 ml of plasma but also caused a non-specific prolongation of the APTT. The polycations protamine, Polybrene, and poly-DL-lysine, possessed clot promoting activity at low concentrations and acted as anticoagulants in their own right at higher concentrations. At a plasma heparin concentration of 4 U/ml, protamine was the most efficient neutralizer of heparin, while at 10 U/ml, Polybrene was the most effective in this respect. It was concluded that care must be taken in the interpretation of the APTT after heparin neutralization or removal as heparin antagonist induced non-specific effects may be present.


Assuntos
Testes de Coagulação Sanguínea , Antagonistas de Heparina/farmacologia , Heparina/sangue , Tempo de Tromboplastina Parcial , Resinas de Troca Aniônica , Brometo de Hexadimetrina/farmacologia , Humanos , Técnicas In Vitro , Polilisina/farmacologia , Protaminas/farmacologia
7.
Vox Sang ; 38(4): 222-8, 1980.
Artigo em Inglês | MEDLINE | ID: mdl-6774480

RESUMO

The effect on cryoprecipitate factor VIII recovery of three imortant variables has been investigated. The design of the study was such as to eliminate, for the purpose of internal comparisons, spurious effects such as those due to the variation in factor VIII levels in donor plasma. The choice of anticoagulant was shown to be of particular significance, plasma collected into CPD anticoagulant giving higher cryoprecipitate factor VIII yield thoughout the study. The effect on cryoprecipitate factor VIII recovery of delay before separation and freezing of the plasma was more complex. Very fresh plasma (separated and frozen within 2 h of collection) gave the highest recovery of factor VIII, but no difference was detected between cryoprecipitate factor VIII recovery of plasma separated and frozen at 4 h and at 18 h after blood collection. Controlled rapid thawing of the plasma was also shown to be advantageous, at least for the preparation of cryoprecipitates from plasma anticoagulated with CPD anticoagulant.


Assuntos
Anticoagulantes/farmacologia , Fator VIII/isolamento & purificação , Congelamento , Doadores de Sangue , Precipitação Química , Humanos , Fatores de Tempo
8.
Br Med J ; 281(6252): 1388-9, 1980 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-6777018

RESUMO

Plasma exchanges were combined with human factor VIII concentrate therapy in the treatment of major bleeding episodes in five patients with haemophilia A and factor VIII inhibitors. All patients had a good clinical response to combined treatment. Inhibitor levels showed satisfactory falls before rapid secondary increases of inhibitor levels took place. A sixth patient with von Willebrand's disease and a factor VIII clotting activity inhibitor was successfully prepared for operation using plasma exchange. Postoperative haemostasis and healing were normal. In two patients the plasma exchanges were relatively more effective than the administered human factor VIII in reducing the levels of factor VIII inhibitor. Combined plasma exchange and human factor VIII treatment may offer a rapidly effective means of reducing factor VIII inhibitor levels in this group of patients, together with significant saving of costs.


Assuntos
Fator VIII/antagonistas & inibidores , Fator VIII/uso terapêutico , Hemofilia A/terapia , Troca Plasmática , Hemofilia A/sangue , Humanos , Masculino , Doenças de von Willebrand/sangue , Doenças de von Willebrand/terapia
9.
Vox Sang ; 58(4): 264-9, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2119086

RESUMO

Donor blood, primarily anticoagulated by acid citrate dextrose formula A (ACD-A), was separated by means of the HemaScience Autopheresis C plasmapheresis device. The citrated plasma was collected directly into a solution of heparin and calcium chloride to achieve a final plasma-ionised calcium concentration of approximately 2 mM, and a heparin concentration of 1.0 IU/ml. Heparin at this concentration provided adequate anticoagulation, and did not result in insoluble cryoprecipitates. Three pairs of donor-matched 4-kg plasma pools (anticoagulant-exchanged variant and ACD-A-anticoagulated control) were constructed and subsequently fractionated to an intermediate stage. The mean recovery of factor VIII from 3 anticoagulant-exchanged pools (394 IU/kg) was 23% greater than the mean recovery from the matched control pools (319 IU/kg). This increased recovery was not achieved at the expense of specific activity.


Assuntos
Anticoagulantes/farmacologia , Ácido Cítrico , Fator VIII/isolamento & purificação , Produtos de Degradação da Fibrina e do Fibrinogênio , Glucose/análogos & derivados , Heparina/farmacologia , Cálcio/análise , Fator VIII/metabolismo , Fibrinopeptídeo A/análise , Fibrinopeptídeo B/análise , Glucose/farmacologia , Humanos , Fragmentos de Peptídeos/análise , Plasmaferese
10.
Hum Genet ; 89(2): 194-8, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1587530

RESUMO

We have used the polymerase chain reaction to amplify two variable number of tandem repeats (VNTRs) within a region of repetitive DNA located in intron 40 of the von Willebrand factor (vWf) gene. Heterozygosity for VNTR I was observed in 30 out of 39 normal unrelated individuals tested (77%), and for VNTR II in 29 out of 44 (66%) similar individuals. Family studies were carried out on 11 kindreds with von Willebrand disease (vWD). Ten of these families were found to be informative for one or other of the VNTRs or for a combination of data from both VNTRs. This method can be used for antenatal diagnosis and for carrier diagnosis in recessive forms of vWD. It is also useful for tracking the gene associated with vWD in type I families where there may be one or more individuals with a phenotypically uncertain diagnosis.


Assuntos
Sequências Repetitivas de Ácido Nucleico/genética , Doenças de von Willebrand/genética , Fator de von Willebrand/genética , Sequência de Bases , Feminino , Frequência do Gene/genética , Triagem de Portadores Genéticos , Humanos , Íntrons/genética , Masculino , Dados de Sequência Molecular , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Genético/genética , Doenças de von Willebrand/diagnóstico
11.
Br J Haematol ; 75(2): 234-9, 1990 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2115374

RESUMO

This study was carried out to assess the efficacy of NHS 8Y concentrate in the treatment of patients with von Willebrand's disease (vWD). Eight patients (two type I vWD, one type IIA vWD, two type IIB vWD, and three type III vWD) were treated on a total of 10 occasions with 8Y. Following each treatment episode there was a temporary correction of patients' bleeding time (BT) measurements. Other laboratory parameters--von Willebrand factor ristocetin cofactor activity (vWf:RiCo), vWf antigen (vWf:Ag) levels, and factor VIII coagulant activity (factor VIII:C)--were also corrected. Plasma vWf multimers temporarily reflected those present in the infused concentrate. An effective clinical response was observed in each case despite, as revealed by autoradiography and scanning densitometry of SDS-agarose electrophoresis gels, a reduction in the concentration of the largest vWf multimers in 8Y compared with normal plasma. Overall, the clinical effectiveness of 8Y in vWD was comparable to that seen with cryoprecipitate. We conclude that NHS 8Y concentrate may be used as an alternative to cryoprecipitate for the treatment of vWD.


Assuntos
Fator VIII/uso terapêutico , Doenças de von Willebrand/tratamento farmacológico , Adulto , Idoso , Antígenos/metabolismo , Tempo de Sangramento , Eletroforese em Gel de Poliacrilamida , Fator VIII/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peso Molecular , Doenças de von Willebrand/sangue , Doenças de von Willebrand/imunologia , Fator de von Willebrand/metabolismo
12.
Clin Endocrinol (Oxf) ; 4(2): 131-8, 1975 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-165913

RESUMO

Seventeen oophorectomized women were treated for 3 month periods, in random sequence, with ethinyl oestradiol 20 and 50 mug daily and conjugated equine oestrogens (Premarin)0-625 and 1-25 mg daily. The serum cholesterol, clot lysis time, plasma fibrinogen, platelet adhesiveness and activated partial thromboplastin time remained unchanged throughout the different oestrogen regimes. There was a significant rise of serum triglyceride levels on both doses of ethinyl oestradiol but no significant change with Premarin. Serum luteinizing hormone levels were depressed most by ethinyl oestradiol 50 mug daily, although no down to the levels in premenopausal women.


Assuntos
Castração , Estrogênios Conjugados (USP)/farmacologia , Etinilestradiol/farmacologia , Adulto , Coagulação Sanguínea/efeitos dos fármacos , Eletroforese das Proteínas Sanguíneas , Colesterol/sangue , Estrogênios Conjugados (USP)/efeitos adversos , Fadiga/induzido quimicamente , Feminino , Fibrinogênio/análise , Humanos , Hormônio Luteinizante/sangue , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Adesividade Plaquetária/efeitos dos fármacos , Radioimunoensaio , Tromboplastina , Triglicerídeos/sangue
13.
Clin Lab Haematol ; 14(1): 9-17, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1600698

RESUMO

A microcomputer database system for the storage, retrieval, and statistical analysis of data associated with the treatment of haemophilia and other defects of haemostasis is described. The hardware requirements are an IBM compatible PC with both hard and floppy disc drives and a suitable printer. The system was written using Smartware II, a powerful integrated software package which incorporates database, word processor, spreadsheet and communications functions. The programs were written with flexibility in mind and can be readily adapted to accommodate the work patterns of any haemophilia centre. This system has now been operational in the Regional Haemophilia Centre at the Manchester Royal Infirmary since January 1990. Its introduction has led to a marked improvement in the efficiency of patient data handling with significant savings in staff time.


Assuntos
Hemofilia A , Sistemas Computadorizados de Registros Médicos , Inglaterra , Controle de Formulários e Registros , Hemofilia A/terapia , Humanos , Sistemas Computadorizados de Registros Médicos/instrumentação , Microcomputadores , Sistema de Registros , Software , Doenças de von Willebrand/terapia
14.
Br J Haematol ; 55(4): 649-55, 1983 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6671085

RESUMO

Successful percutaneous liver biopsy was carried out on 12 multi-transfused haemophiliacs from the Manchester area with persistently abnormal liver function tests. Only one patient showed evidence of chronic active hepatitis with progression to active micronodular cirrhosis although a further four patients showed some evidence of mild chronic active hepatitis. This represents a much lower incidence of severe histological liver damage than many previous reports and implies that liver biopsy in asymptomatic haemophiliacs may not be indicated as a routine procedure, particularly in the absence of proven therapy. Dynamic liver function tests may prove to be a useful indicator of deteriorating liver function in the otherwise asymptomatic haemophiliac.


Assuntos
Hemofilia A/complicações , Hepatite Crônica/complicações , Adolescente , Adulto , Galactose/metabolismo , Hemofilia A/patologia , Hepatite Crônica/sangue , Hepatite Crônica/patologia , Humanos , Fígado/patologia , Testes de Função Hepática , Transaminases/sangue
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