scholarly journals An Automated one Stage Assay Technique for the Routine Evaluation of Factor VIII Concentrates

1977 ◽  
Author(s):  
M. Miller-Andersson ◽  
M.J. Seghatchian ◽  
T. Kirkwood ◽  
I.M. Nilsson
Keyword(s):  
Large Scale ◽  
Assay System ◽  
Automated System ◽  
Collaborative Studies ◽  
Factor Viii Concentrates ◽  
Assay Methods ◽  
The Given ◽  
In Vivo Recovery ◽  
Good Agreement

There is a general need for a reliable automated F VIII assay system with a large capacity for block bioassays. We present a method fulfilling these requirements. A rebuilt device for APTT determinations based on an optically clear activator and an artificial F VIII deficient substrate plasma has been used continously for 2 years. The substitution of hemophilia plasma by an artificial substrate plasma is a necessary feature for any satisfactory large scale automated system. There was no evidence of any differences between results obtained using this substrate and congenital deficient plasma. The reproducibility of the assay system was very good.(S.D. ≈ 10 %). And the results obtained by two different machines where indistingquish-able. The results showed very good agreement between the relative potency estimates of known F VIII standards obtained with this method and those found at recent international collaborative studies. However, comparison of assay results of clinical F VIII preparations with estimates of in vivo recovery shows that this method estimates lower potency of the given concentrates. These finding is in accordance with several other studies, that has shown that different assay methods detect relatively differing activities in preparations of different purity. Since it is important that the labeled unitage of the clinical material should continue to produce the same measured in vivo recovery at the “Reference Hemophilia Centre” (Malmö, Sweden), we have calculated simple convertion factors to apply to the assay results eliminating the appearent différencies.

HALF-LIFE AND IN-VIVO RECOVERY OF HEATED FACTOR VIII CONCENTRATES

The Lancet ◽  
1986 ◽  
Vol 328 (8506) ◽  
pp. 571-572 ◽  
Author(s):  
M. Morfini ◽  
A. Messori ◽  
G. Longo ◽  
S. Cinotti ◽  
M. Matucci ◽  
...  
Keyword(s):  
Factor Viii ◽  
Half Life ◽  
Factor Viii Concentrates ◽  
In Vivo Recovery

In Vivo Recovery and Survival of Monoclonal-Antibody-Purified Factor VIII Concentrates

1991 ◽  
Vol 66 (06) ◽  
pp. 730-733 ◽  
Author(s):  
Carol K Kasper ◽  
Hugh C Kim ◽  
Edward D Gomperts ◽  
Kenneth J Smith ◽  
Phyllis M Salzman ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Factor Viii ◽  
In Vitro Assays ◽  
Two Stage ◽  
Double Blind ◽  
One Stage ◽  
Factor Viii Concentrates ◽  
In Vivo Recovery

SummaryIn response to reports of discrepant in vitro assays of high-purity concentrates, a double-blind crossover study of in vivo recovery and half-life of two brands of monoclonal-antibody-purified factor VIII concentrates (Monoclate and Hemofil-M) was performed in 23 patients with hemophilia A. In vivo recoveries were close to values predicted from the labelled unitage when plasma samples were assayed by a one-stage method. When a two-stage assay was used, lower recoveries were calculated and the recovery with Hemofil-M was slightly but significantly lower than that with Monoclate. The concentrates were re-assayed in vitro by the two-stage method. Monoclate (which is assayed by the manufacturer using a two-stage method) contained 97% of the labelled potency and Hemofil-M (which is assayed by the manufacturer using a one-stage method) contained 81% of the labelled potency. Differences in in vitro and in vivo assay methods contribute to disparities between expected and observed factor VIII recovery. Clearance of Hemofil-M was significantly faster than that of Monoclate, but volume of distribution at the steady state, mean residence time, and plasma half-disappearance times of the two concentrates were not significantly different.

scholarly journals A semi-automated system for quantifying the oxidative potential of ambient particles in aqueous extracts using the dithiothreitol (DTT) assay: results from the Southeastern Center for Air Pollution and Epidemiology (SCAPE)

2014 ◽  
Vol 7 (7) ◽  
pp. 7245-7279 ◽  
Author(s):  
T. Fang ◽  
V. Verma ◽  
H. Guo ◽  
L. E. King ◽  
E. S. Edgerton ◽  
...  
Keyword(s):  
Air Pollution ◽  
Large Scale ◽  
Limit Of Detection ◽  
Water Soluble ◽  
Automated System ◽  
Oxidative Potential ◽  
Data Set ◽  
Ambient Particles ◽  
Southeastern Us

Abstract. A variety of methods are used to measure the capability of particulate matter (PM) to catalytically generate reactive oxygen species (ROS) in vivo, also defined as the aerosol oxidative potential. A widely used measure of aerosol oxidative potential is the dithiothreitol (DTT) assay, which monitors the depletion of DTT (a surrogate for cellular antioxidants) as catalyzed by the redox-active species in PM. However, a major constraint in the routine use of the DTT assay for integrating it with the large-scale health studies is its labor-intensive and time-consuming protocol. To specifically address this concern, we have developed a semi-automated system for quantifying the oxidative potential of aerosol liquid extracts using the DTT assay. The system, capable of unattended analysis at one sample per hour, has a high analytical precision (Coefficient of Variation of 12% for standards, 4% for ambient samples), and reasonably low limit of detection (0.31 nmol min−1). Comparison of the automated approach with the manual method conducted on ambient samples yielded good agreement (slope = 1.08 ± 0.12, r2 = 0.92, N = 9). The system was utilized for the Southeastern Center for Air Pollution and Epidemiology (SCAPE) to generate an extensive data set on DTT activity of ambient particles collected from contrasting environments (urban, road-side, and rural) in the southeastern US. We find that water-soluble PM2.5 DTT activity on a per air volume basis was spatially uniform and often well correlated with PM2.5 mass (r = 0.49 to 0.88), suggesting regional sources contributing to the PM oxidative potential in southeast US. However, the greater heterogeneity in the intrinsic DTT activity (per PM mass basis) across seasons indicates variability in the DTT activity associated with aerosols from sources that vary with season. Although developed for the DTT assay, the instrument can also be used to determine oxidative potential with other acellular assays.

In Vivo and In Vitro Comparison of Various Factor VIII Concentrates

1977 ◽  
Author(s):  
I.M. Nilsson ◽  
U. Hedner
Keyword(s):  
Factor Viii ◽  
Half Life ◽  
The Other ◽  
Crossed Immunoelectrophoresis ◽  
Factor Viii Concentrates ◽  
Fibrinogen Content ◽  
In Vivo Recovery ◽  
In Vitro Comparison

Five different factor VIII concentrates, AHF-Kabi(=fraction 1-0), Krynativ-Kabi(=cryoprecipitate), Hemofil-Hyland, AHF-Profilate-Abbott, Kryobulin-Immuno, available in Sweden for treatment of haemophiliacs were compared with respect to in vivo recovery of F VIII:C and survival time and in vitro properties. The parameters studied were F VIII:C, F VIIIR:AG, crossed Immunoelectrophoresis, F VIII:Rcof, fibrinogen content and F XIII activity. All the preparations had higher values for F VIIIR:AG than for F VIII:C. The quotient was highest for Hemofil, Krynativ-Kabi and Kryobulin and varied between 4 and 7. The lowest quotient, 1.3 to 4, showed AHF-Kabi. The units of F VIII:Rcof were almost the same as the units of F VIII:C. AHF-Kabi had the highest fibrinogen content and was the only preparation with high amounts of F XIII. In cross Immunoelectrophoresis AHF-Kabi showed a similar pattern to that of normal plasma. The other preparation had a different pattern suggesting less hetero-genicity of the molecule. The in vivo recovery was about the same for all the concentrates but AHF-Kabi had a significantly longer half-life (18-26 hrs); the corresponding figures for Hemofil were 8-16 hrs when given to the same patients. Only AHF-Kabi was able to completely normalize the defect in von Willebrand’s disease.

scholarly journals A semi-automated system for quantifying the oxidative potential of ambient particles in aqueous extracts using the dithiothreitol (DTT) assay: results from the Southeastern Center for Air Pollution and Epidemiology (SCAPE)

2015 ◽  
Vol 8 (1) ◽  
pp. 471-482 ◽  
Author(s):  
T. Fang ◽  
V. Verma ◽  
H. Guo ◽  
L. E. King ◽  
E. S. Edgerton ◽  
...  
Keyword(s):  
Air Pollution ◽  
Large Scale ◽  
Limit Of Detection ◽  
Water Soluble ◽  
Automated System ◽  
Oxidative Potential ◽  
Data Set ◽  
Ambient Particles ◽  
Southeastern Us

Abstract. A variety of methods are used to measure the capability of particulate matter (PM) to catalytically generate reactive oxygen species (ROS) in vivo, also defined as the aerosol oxidative potential. A widely used measure of aerosol oxidative potential is the dithiothreitol (DTT) assay, which monitors the depletion of DTT (a surrogate for cellular antioxidants) as catalyzed by the redox-active species in PM. However, a major constraint in the routine use of the DTT assay for integrating it with large-scale health studies is its labor-intensive and time-consuming protocol. To specifically address this concern, we have developed a semi-automated system for quantifying the oxidative potential of aerosol liquid extracts using the DTT assay. The system, capable of unattended analysis at one sample per hour, has a high analytical precision (coefficient of variation of 15% for positive control, 4% for ambient samples) and reasonably low limit of detection (0.31 nmol min−1). Comparison of the automated approach with the manual method conducted on ambient samples yielded good agreement (slope = 1.08 ± 0.12, r2 = 0.92, N = 9). The system was utilized for the Southeastern Center for Air Pollution & Epidemiology (SCAPE) to generate an extensive data set on DTT activity of ambient particles collected from contrasting environments (urban, roadside, and rural) in the southeastern US. We find that water-soluble PM2.5 DTT activity on a per-air-volume basis was spatially uniform and often well correlated with PM2.5 mass (r = 0.49 to 0.88), suggesting regional sources contributing to the PM oxidative potential in the southeastern US. The correlation may also suggest a mechanistic explanation (oxidative stress) for observed PM2.5 mass-health associations. The heterogeneity in the intrinsic DTT activity (per-PM-mass basis) across seasons indicates variability in the DTT activity associated with aerosols from sources that vary with season. Although developed for the DTT assay, the instrument can also be used to determine oxidative potential with other acellular assays.

The Importance of Corticoids Added to Continued Treatment with Factor VIII Concentrates in the Suppression of Inhibitors in Haemophilia A

1984 ◽  
Vol 51 (02) ◽  
pp. 217-221 ◽  
Author(s):  
J A Aznar ◽  
J I Jorquera ◽  
A Peiró ◽  
I Garcia
Keyword(s):  
Factor Viii ◽  
Prophylactic Treatment ◽  
Haemophilia A ◽  
Progressive Reduction ◽  
Anamnestic Response ◽  
Factor Viii Concentrates ◽  
Rehabilitation Exercises ◽  
Therapeutic Administration ◽  
In Vivo Recovery

SummaryA protocol is presented to suppress inhibitors in haemophilia A using continued treatment with f. VIII (50 U/kg b.w./day) and fluprednisolone (0.5 mg/kg b.w., for 21 days) until reaching correct in vivo recovery after therapeutic administration.5 high responder patients were treated whose inhibitors were detected at least 2 years before beginning the treatment. The inhibitors were eradicated in 4 patients using continued treatment for between 4 and 24 months. Patient 1 was treated exclusively with factor and the others also with corticoids when the level was 0 B.U. (or 20 B.U., patient 4). The patients began tri-weekly prophylactic treatment and rehabilitation exercises after recovery test normalization. After progressive reduction of the prophylactic treatment they started on demand treatment. After more than 5 months of this treatment no anamnestic response has been detected in any patient, in spite of several factor VIII administrations.

In Vivo Recovery of Factor VIII Following Transfusion: A Survey of Recent Data and Publications to Assess the Influence of Standards Used for Potency Assignment

1995 ◽  
Vol 74 (04) ◽  
pp. 1191-1196 ◽  
Author(s):  
C V Prowse
Keyword(s):  
Factor Viii ◽  
Coagulation Factor ◽  
Target Level ◽  
Limited Data ◽  
Plasma Coagulation ◽  
Chromogenic Assay ◽  
Post Infusion ◽  
Assay Methods ◽  
In Vivo Recovery

SummaryIn the therapy of factor VIII deficiency, experience has taught the value of achieving a target level of plasma coagulation factor VIII. There is a consensus that an empirical value of 2 iu/dl/iu/kg may be used to estimate recovery, and hence plasma levels, of factor VIII. This may be influenced by the methods used to assign label potency to the products and for assessment of patient post-infusion plasmas. To assess a possible influence of the standard used to assign product potency on in vivo recovery, a survey was undertaken of recent in vivo recovery studies. Analysis of submitted data, in combination with published studies over the last ten years, revealed a significant influence of the standard used to assign potency to products on the measured in vivo recovery. Furthermore, from limited data the potency determined in post-infusion patient plasmas was found not to be influenced by the use of one-stage or chromogenic assay methods.

Potency and In Vivo Recovery of High Purity Factor VIII Concentrates

1994 ◽  
Vol 72 (01) ◽  
pp. 160-161 ◽  
Author(s):  
Marianne Mikaelsson ◽  
Ulla Oswaldsson ◽  
Inga Marie Nilsson
Keyword(s):  
Factor Viii ◽  
High Purity ◽  
Factor Viii Concentrates ◽  
In Vivo Recovery

Purification of the Antihemophilic Factor by Gel Filtration on Agarose

1969 ◽  
Vol 22 (03) ◽  
pp. 577-583 ◽  
Author(s):  
M.M.P Paulssen ◽  
A.C.M.G.B Wouterlood ◽  
H.L.M.A Scheffers
Keyword(s):  
Factor Viii ◽  
Plasma Proteins ◽  
Large Scale ◽  
Gel Filtration ◽  
Large Scale Preparation ◽  
Scale Preparation ◽  
Antihemophilic Factor

SummaryFactor VIII can be isolated from plasma proteins, including fibrinogen by chromatography on agarose. The best results were obtained with Sepharose 6B. Large scale preparation is also possible when cryoprecipitate is separated by chromatography. In most fractions containing factor VIII a turbidity is observed which may be due to the presence of chylomicrons.The purified factor VIII was active in vivo as well as in vitro.

A Comparative Ex Vivo Study of Plasminogen Activators and Proteases for Fibrinolytic Activity and Side Effects in Rabbits

1977 ◽  
Vol 37 (01) ◽  
pp. 154-161 ◽  
Author(s):  
B. A Janik ◽  
S. E Papaioannou
Keyword(s):  
Side Effects ◽  
Effective Dose ◽  
Fibrinolytic Activity ◽  
Ex Vivo ◽  
Plasminogen Activators ◽  
Assay System ◽  
Coagulation Parameters ◽  
Ex Vivo Assay

SummaryUrokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose, were administered to monitor potential toxicity revealing that Brinase, trypsin, and SN 687 were very toxic at this concentration.Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo.The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.

Sign in / Sign up

Export Citation Format

Share Document