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Biomedical subjects

E Bidwell

Publications and source records attributed to E Bidwell.

At least 19 recordsLinked to original sources

A factor VII concentrate for therapeutic use.

A concentrate of factor VII suitable for therapeutic use has been prepared from human plasma by a method forming part of a comprehensive scheme of large-scale plasma fractionation. Factor VIII was separated as cryoprecipitate and factors II, IX and X were adsorbed on DEAE-cellulose. Most of the factor VII remained in the supernatant. By batch adsorption on DEAE-Sepharose, followed by elution on a chromatographic column, factor VII was concentrated about 25-fold, and purified about 50-fold compared with original plasma, without the need for further dialysis or concentration steps. Data are presented from 10 batches, each from 80-120 kg plasma. Following doses of factor VII to six congenitally deficient patients, the mean rise in plasma factor VII was 95-100% of theoretical; the half-disappearance time was about 4 h. The treatment of four patients with acquired deficiency of factor VII is also described. No untoward side effects were observed.

Adult↗

Anti-A haemagglutinins in factor VIII concentrates.

Experimental evidence has been obtained that cryoprecipitation concentrates anti-A in mixtures of group O and group A plasma by a mechanism that does not operate in group O plasma alone. It has been concluded that the anti-A/A polysaccharide complex is less soluble during cryoprecipitation than anti-A immunoglobulin, and this complex dissociates to give free anti-A when the cryoprecipitate is redissolved. From a practical point of view, factor VIII concentrates prepared from cryoprecipitate obtained from single donations of plasma unselected for ABO group contain significantly less anti-A than those prepared from mixing pools of plasma in which partial neutralisation of anti-A has occurred before cryoprecipitation.

ABO Blood-Group System↗

Coagulation factor concentrate in the treatment of the haemorrhagic diathesis of fulminant hepatic failure.

To assess the value of clotting factor concentrate infusions in fulminant hepatic failure, a controlled trial was performed in which nine patients were randomly allocated to treatment with either concentrate alone or concentrate plus heparin. The five patients receiving concentrate alone all died, with major bleeding as the direct cause of death in three, whereas in the four receiving heparin as well there was only one instance of bleeding and one patient survived. Clinical evidence of intravascular coagulation appeared in two patients treated with concentrate alone and the laboratory evidence of this progressed during the period of infusions in all patients in both treatment groups, although to a lesser extent in those receiving heparin. Additional evidence for intravascular coagulation came from the changes observed in factor VIII levels which, although initially high in all patients, fell subsequently, particularly in those given concentrate alone. There was some improvement in the prothrombin ratio in both groups of patients but not complete correction, and serial assays of clotting factors showed that although factor II rose to high levels during treatment, factors IX and X showed little response. Thus, the use of concentrate of factor IX in this trial, as well as potentiating intravascular coagulation, was inadequate as replacement for the clotting factor deficiencies.

Acute Disease↗

Cross-reacting material in genetic variants of haemophilia B.

Cross-reacting factor IX material (CRM) was immunologically detected in the plasma of 38 normal individuals and 21 out of 22 haemophilia B patients using a rabbit antibody to factor IX. The same reacting material was detected in only nine of these patients using a human antibody. These results indicate that the plasma of the majority of haemophilia B patients contains a protein-lacking biological activity but having antigenic determinants in common with normal factor IX.

Animals↗