摘要:

New approaches and techniques for improving source material collection and factor VIII production at Blood Bank level have been reported recently. Heparin has shown to be of great importance in increasing both yield and stability of factor VIII in the purification and concentration process. Work has been done to develop on a routine scale a heparin double cold‐precipitation technique for the production of freeze‐dried high yield purified factor VIII concentrate. As a spin‐off of the method red cell concentrate (RCC) and cryosupernatant plasma (SDP), both containing small amounts of heparin besides the standard CPDA‐1 anticoagulant, are recovered for clinical use. Results of the tests done:RCC ‐in vitro: Normal Adenosin Tri‐Phosphate (ATP), 2 3 Di‐Phospho‐Glycerate (DPG) and shelf‐life, Heparin 0.7 IU/ml (±0.3).‐in vivo: Normal half51Cr‐survival, no side effects.SDP ‐in vitro: Protein and chemical analysis normal, shelf‐life normal, Heparin 3.5 IU/ml (±0.7).‐in vivo: No side‐effects, mild effect on activated Partial Thromboplastin Time (aPTT) 5 minutes post transfusion.Factor VIII concentrate ‐in vitro: Yield 56.2 (±8.2) percent, purity 0.8 (±0.15) FVIII:C IU/mg protein, potency 25.2 (±3.2), FVIII:C IU/ml Heparin 6.2 (±0.7) IU/ml.‐in vivo: Normal recoveries and half‐lifes after injection of 15–20 IU/kg in 4 severe hemophilia A patients.This heparin small pool high yield principle is expected to have great impact on availability, access to and safety of ade

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02552.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A newly introduced purification method has been shown to yield in a final product of good characteristics when prime quality plasma was used in small scale. In order to assess the importance of the plasma quality in production of very high purity AHF concentrate, cryopre‐cipitates originating from various kinds of starting plasmas were fractionated according to the purification method. The parameters investigated in this study were: a) the blood group, b) age of plasma, c) storage time of plasma and d) the role of thrombin activation as monitored by FPA level. The yield of FVIII:C in the cryoprecipitate varied depending on the quality of starting plasma. In average, the relative proportion of FVIII:C which could be recovered in the final product was independent from the quality of starting plasma. The overall yields per liter of plasma were, however, decreased when starting plasma of low quality was use

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02553.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Plasma was frozen in two types of ampoules with different freezing equipments. Changes in temperature were recorded with thermocouples and the quality of frozen plasma determined by analysis of F VIII:C. Temperature decreased rapidly to the freezing point where it stayed during the phase change to ice and was followed by a second rapid decrease down to the final temperature. The time for duration at the freezing point decreased with thinner plasma layers. Freezing was accomplished faster with ‐40°C ethanol baths than with different types of freezeboxes. Use of flat 750 ml ampoules resulted in shorter freezing times than with cylindric 1,500 ml ampoules. The factor VIII:C recovery in frozen plasma increased with faster rate of freezing. The purity and recovery of F VIII:C in cryoprecipitates increased with fast freezing of plas

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02554.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Reference standards for factor VIII are necessary because of the wide variation of factor VIII:C in normal plasma and its instability. A stable freeze‐dried concentrate was established as the 1st International Standard by comparison with fresh normal plasma in many laboratories. Replacement standards have since been calibrated against the previous standards and also compared with average normal plasma collected from large numbers of donors. National standards have been established in several countries and have existed for many years in the U.K. and U.S.A. These are calibrated against the international standard in collaborative studies. Concentrate standards should be used for assay of therapeutic concentrates. Plasma standards are most appropriate for patients' plasma samples, and calibration of these against the international standard concentrate has led to discrepancies between laboratories and between assay methods. An international reference preparation of factor VIII plasma has therefore been established, and this has been calibrated for other VIII‐related activities as well as VII

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02555.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A chromogenic method for the determination of factor VIII:C in plasma and concentrate has been developed. Bovine factor Xais generated in a system containing bovine factors IXaand X, Ca2+and phospholipid. The amount of factor Xaformed is directly proportional to the amount of factor VIII:C. Thus, after hydrolysis of the factor Xaselective chromogenic substrate S‐2222, the colour produced by released p‐nitroaniline is linearly related to the concentration of factor VIII:C in the sample. Hydrolysis of the substrate by thrombin is prevented by including the thrombin inhibitor I‐2581. A major methodological advantage is the exclusion of hemophilia A plasma or artificially prepared factor VIII deficient plasma.The detection limit is 1 per cent factor VIII:C, and the CV is lower than 5 per cent in both the earlier defined ranges, 1–20 per cent and 15 ‐ 100 per cent factor VIII:C and in the recently introduced extended range 20–150 per cent factor VIII:C. The resolution in the 15–100 per cent range is about 0.008 absorbance units per per cent factor VIII:C, allowing a good discrimination between samples containing e.g. 30–70 per cent factor VIII:C.Comparative studies between the chromogenic assay and clotting assays have been performed in other laboratories with both plasma and concentrate samples and the correlation coefficient was in a

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02556.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02557.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

In view of reports of less than labelled F VIII:C content in some lots of commercially available f VIII concentrates, a multi‐center prospective study of f VIII concentrate potency was organized in collaboration with the United States Bureau of Biologics (BoB). Phase one of the study was aimed at evaluating the reproducibility of F VIII:C assays (one stage) in the participating laboratories, using: 1) A uniform assay method, and 2) Each lab's in‐house method. Reproducibility was better with the latter. Phase two consisted of: 1),In vitroassays of currently available F VIII concentrates, and 2)In vivoF VIII:C recovery studies in two severe hemophilia A subjects. Three different lots of concentrate from each of eight different products were used for these studies. Lots were randomly selected from those available in spring‐summer 1982.Each lab used its in‐house F VIII:C method, with lyophilized standards provided by BoB. All values were read against three standards: In‐house, BoB A (concentrate standard) and BoB s (plasma standard). Baseline, 15 and 45 minute samples from thein vivorecovery studies were snap‐frozen and stored at ‐70°C, then shipped in dry ice. All plasma samples were assayed as unknowns in each of nine participating labs (the authors‘, Hyland, Cutter and BoB). Statistical analysis of data for 24 lots of concentrate (three lots each from Cutter, Hyland, Alpha, Armour, N.Y. Blood Center, American Red Cross‐Cutter, American Red Cross‐Hyland, Michigan Department of Health) revealed the following: Inter‐lab values of in vitro assays of concentrate compared best when BoB A (concentrate standard) was used. Mean values corresponded to those on the manufacturers' labels, and in some instances were higher. In vivo studies revealed better than “expected” F VIII:C recovery with each product tested. In the in vivo studies inter‐lab values (for f VIII:C assays of the plasma samples) compared very well when BoB 5 (plasma standard) was used. In bothin vitroand in vivo studies there was much greater inter‐laboratory variation in results whe

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02558.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Factor VIII preparations available to the clinician are numerous and vary greatly in their mode of preparation, potency, purity and potential side effects. In vivo behaviour of Factor VIII:C from each product should be studied systematically. Collection of useful and valid information on VIII:C recovery and half‐life requires the observance of rather strict rules.1Standards. The dose of infused VIII:C can be calculated either from the labeled value or from local measurement using as reference a concentrate calibrated against the WHO concentrate standard. VIII:C plasma levels are tested using a plasma reference calibrated against the WHO plasma standard.2Patients. Severe hemophilia A patients non bleeding or bleeding in small capacity joint and not treated for at least five days without inhibitor are selected.3Dose. At least 20 u/kg body weight of VIII:C are infused.4Sampling. Plasma samples collected before,15, 30 and 60 minutes post‐infusion allow to identify the peak of VIII:C activity from whichin vivorecovery is calculated. Samples collected 4,8–12,24 and 36–48 h post‐infusion allow to evaluate F VIII:C half‐life on the basis of VIII:C plasma levels measured in 4 of these samples.5Assays. VIII:C one or two‐stage assays are equally acceptable although only one‐stage assays detect activated VIII:C. Plasma samples from a patient are stored at ‐70°C and all tested in one session.6Calculations.In vivorecovery is estimated as percent of a theoretical value obtained either on the basis of 1 u/kg VIII:C provides 0.02 u VIII:C/ml plasma or of a calculated plasma volume. Various calculation programs seem suitable for evaluation o

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02559.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

In vivo recovery. Differences between laboratories depend on the time of sampling, factor VIII:C assay method, factor VIII:C plasma standard and the calculation of the patients' plasma volume. The results depend on whether the manufacturer's labelled potency or the factor VIII:C potency of the laboratory is used. In some countries the vials are labelled with a nominal potency ± 20 percent.Half‐life. Most publications have shown that the factor VIII:C activity‐time curve fits a two‐compartment model. The elimination half‐life is about 12 h. The initial half disappearance time or distribution half‐life is used by some authors. However, very often the half‐life has not been defined. The data collection period has been too short and the formula for the calculation has not been presented. The large intersubject variability may be due to the quality of the data collection and analysis. There are many pitfalls in deriving pharmacokinetic variables. Do we need a pharmacokinetic model, and, if s

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02560.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0036-553X    

DOI:10.1111/j.1600-0609.1984.tb02561.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY