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Biomedical subjects

H Suomela

Publications and source records attributed to H Suomela.

At least 19 recordsLinked to original sources
PubMed1993

Microtiter plate assay for measuring the anticomplementary activity of immunoglobulins.

An anticomplementary activity (ACA) assay on a microtiter plate combined with a computer-controlled plate reader and computerized calculation of the assay result is described. The assay is a simplified version of existing ones and can be used to assay immunoglobulins at low protein concentrations. The method detects the consumption of 0.13 CH50U, corresponding to anticomplementary activity of 7.5 CH50U/g protein. The assay has a coefficient of variation of 20.4%.

Antibodies↗
PubMed1992

Virus inactivation during intravenous immunoglobulin production.

Effects of time, temperature, pH and stabilizers (i.e. medium) on inactivation of lipid-enveloped model viruses, Semliki Forest and vesicular stomatitis viruses in the production process of intravenous immunoglobulin were investigated on a laboratory scale. The lowering of pH, the raising of temperature and the increasing of incubation time improved the inactivation effect. However, small changes in pH and stabilizer concentrations did not influence the results. Inactivation was not linear and a clear tailing off could be seen. Therefore, for complete virus inactivation incubation times longer than 20 h are necessary. Inactivation took place much more rapidly in intravenous immunoglobulin solution than in intramuscular immunoglobulin solution. Processing steps such as freeze-dying in the presence of ethanol or storage of intramuscular immunoglobulin in the liquid state at pH7 only partially inactivated these viruses.

Blood Transfusion↗
PubMed1991

Stability of European anti-D immunoglobulin preparations.

The stability of 18 batches of anti-D immunoglobulin preparations from 7 European manufacturers was studied over 28-day incubation at +37 degrees C and 3-year storage at +4 degrees C. The mean loss of activity after 28 days at +37 degrees C was 12.3 +/- 8.2%, and after 3 years at +4 degrees C 15.2 +/- 9.5%. The correlation coefficient of the loss of activity between these two storages was r = 0.61, p less than 0.05 indicating that short-term incubation can be used to evaluate the shelf life stability of anti-D activity. In general, measurements of IgG fragments or activities of plasmin, plasminogen, or prekallikrein activator were not valuable in predicting the stability of anti-D activity due to the fact that the preparation of each manufacturer has its own unique pattern of enzymes and inhibitors. The anti-D immunoglobulin preparations contained up to at least 7 plasma proteins in addition to IgG. All preparations contained factor B, most of them alpha 2-macroglobulin, alpha 1-antitrypsin, albumin, and alpha 2-HS glycoprotein, alpha-Lysozyme was present in 7, and ceruloplasmin in 2 preparations. Neither purity nor impurity correlated with stability.

Chromatography, High Pressure Liquid↗
PubMed1984

High-performance liquid chromatography in the quality control of immunoglobulin preparations during production and storage.

High-performance liquid chromatography (HPLC) has been used in the routine quality control of immunoglobulin preparations to measure the contents of aggregates, dimers, monomers and degradation products. The correlation coefficients between TSK 3000 SW, Ultrogel AcA 34 and Sephacryl S-300 chromatography were calculated and a reasonable correlation was found. The decrease in the potency of anti-tetanus immunoglobulin at room temperature was accompanied by an increase in degradation products. The speed and high sensitivity of HPLC make it suitable for the detection of aggregates in intravenous immunoglobulin preparations.

Chromatography, High Pressure Liquid↗
PubMed1982

An optimized assay for prekallikrein activator activity in human plasma products.

Prekallikrein activator (PKA) assay is described. PKA was measured indirectly by allowing it to generate kallikrein from prekallikrein and then measuring the amidolytic activity of kallikrein by using the synthetic chromogenic substrate S-2302. It was ensured that sufficient amounts of substrates were included in both enzymatic phases of the assay, and the pH and ionic strength which seemed to be very important in the assay were carefully controlled. Both a kinetic assay and a simple endpoint assay are described. Other amidolytic enzymes probably present in plasma products are also estimated and a correction is made to exclude their role in the assay result. The precision of the kinetic assay is characterized by the coefficient of variation of 3.1% within an assay and the reproducibility by that of 4.8% between assays. For the endpoint assay both values are 4.8%.

Amidohydrolases↗
PubMed1982

The stability of factor IX concentrate during storage.

A storage study of factor IX concentrate was performed on 35 randomly selected batches that had been prepared between 1976 and 1980. Vacuum stability, dissolution time, F IX procoagulant activity, NAPTT, and thrombin generation were measured immediately after the manufacturing process and compared in this study with the results obtained from the spare samples analysed in 1981. No significant changes during storage at cold room temperature for up to 5 years were established. The product can thus be considered to be stable for 5 years at + 4 degrees C.

Drug Stability↗
PubMed1982

Correlation of hypotensive effect of plasma protein fraction with prekallikrein activator activity: a clinical study in patients having open-heart surgery.

We studied the hemodynamic responses to the administration of 20 ml of three protein solutions having different prekallikrein activator (PKA) activities in patients undergoing cardiac operation. PKA levels of the two plasma protein fraction (PPF) solutions studied were 193% and 60%, respectively, while that of the albumin solution was less than or equal to 3%. A significant correlation was found between the PKA activity of the test solutions and the decrease in systemic vascular resistance produced by the solutions during cardiopulmonary bypass and in the postoperative period. Vasodilatation was considerably more marked in the postoperative phase than during cardiopulmonary bypass. Since cardiac output increased simultaneously with the decrease in vascular resistance in the postoperative period, the hypotension observed did not fully reflect the degree of vasodilatation. In some patients, substantial vasodilatation was observed also after the administration of albumin solution with low PKA level. We conclude that although the PPF-induced vasodilatation correlates with the PKA activity of the solution, occasional hypotensive reactions are probably due to mechanisms other than those linked with increased PKA level.

Adult↗
PubMed1979

Stability of IgG solutions, especially anti-D gammaglobulin, with special reference to measured proteolytic activity and degradation.

The stability of IgG solutions during the dating period can be predicted by measuring the degree of degradation after elevated storage conditions at +37 degrees C with added streptokinase. The measurement of proteolytic activity with a synthetic substrate correlates with the results obtained by SDS-disc gel electrophoresis and gel filtration. IgG molecules having Anti-D activity were observed to be essentially more sensitive to proteolytic degradation by plasmin than IgG molecules in general. It seems, therefore, that the methods which are suitable for the study of the stability of normal IgG preparations are not sufficient to predict the stability of anti-D gammaglobulin preparations.

Drug Stability↗
PubMed1977

Preparation and properties of a therapeutic factor IX concentrate.

A method for the large-scale preparation of a coagulation factor IX concentrate from human plasma is described. The method includes absorption of the coagulation factors from cryosupernatant plasma to DEAE-Sephadex, extensive washing of the gel and elution of the coagulation factors with 0.5 M phosphate buffer at 6.85, followed by desalting of the eluate in a column of Sephadex G-25, then by lyophilization, dissolving and sterile filtration, and finally by freeze-drying of the final product. Experiments performed with HBsAg-positive plasma demonstrated a decrease in the HBsAg content by a factor of 10(-5) during the process. The product is inactive in a Na-PTT assay. The process yields an about 100-fold purified factor IX concentrate containing also factors II, VII, and X, but in relatively smaller amounts. The average yield relative to factor IX is 60%. The batch size has been from 16 to 150 litres of plasma and about 300 batches of the concentrate have been prepared. About 5,100 bottle (about 4.0 X 10(6) U of factor IX) of the concentrate have been used in the treatment of patients with haemophilia B. The clinical effect has always been good and the in vivo response to factor IX was 1.15 +/- 0.30%/U/kg body weight. Two cases of HBsAg-negative hepatitis that may have been caused by the concentrate, were detected. No thrombotic complications were found.

Factor IX↗
PubMed1976

Purification of human factor IX by chromatography of a coagulation factor concentrate.

A purification procedure for, and some properties of, coagulation factor IX are described. The coagulation factor concentrate used for the treatment of hemophilia B patients was employed as the starting material. The isolation procedure consists of chromatography in DEAE-cellulose, two chromatographies in hydroxyapatite gel and two gel filtrations in Sephadex G-200. Only trace amounts of factors II, VII and X were present in the final preparation and the specific activity of factor IX was 159 corresponding 10,300 times purification from plasma. The molecular weight was estimated to be 76,000 in gel filtration and 86,000 in sodium dodecyl sulfate disc gel electrophoresis. Three activity peaks with pIs 4.15, 4.25 and 4.40 were obtained by isoelectric focusing.

Chromatography, DEAE-Cellulose↗
PubMed1976

Human coagulation factor IX. Isolation and characterization.

Human coagulation factor IX was purified by two ion-exchange chromatographies on DEAE-Sephadex A-50, heparin-Sepharose chromatography, hydroxyapatite chromatography and immunoadsorbent technique. Factor IX was homogeneous by ordinary and sodium dodecylsulphate disc electrophoresis, N-terminal amino acid analyses and ultracentrifugation and by immunological criteria. The following molecular data were observed: 1. Sedimentation equilibrium indicated a molecular weight of 66100 and sedimentation velocity gave S20,W = 3.97 S. A partial specific volume of -v = 0.712 ml/g was calculated from the amino acid and carbohydrate composition. 2. Sodium dodecylsulphate disc gel electrophoresis suggested a molecular weight of 65000. 3. Gel filtration indicated a Stokes radius of 4.08 nm, and 'a molecular weight' of 72000, as well as a diffusion coefficient D20,W = 5.15 X 10(-7) cm2 s-1 and a frictional ratio f/fo = 1.54. 4. Tyrosine was the N-terminal amino acid. The amino acid composition is described. Factor IX contained approximately 17.5% carbohydrate, which includes 4.7% hexose, 6.8% N-acetylhexosamine and 6% sialic acid. 5. Microheterogeneity of pure factor IX was demonstrated by isoelectric focusing. The isoelectric points of the major components lay within range of pH 4.0 to 4.6. 6. The antibody raised in rabbits against the pure factor IX did not react with the other vitamin-K-dependent coagulation factors measured by coagulation factor assays or immunodiffusion in gels.

Amino Acids↗