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Biomedical subjects

H Friedli

Publications and source records attributed to H Friedli.

13 recordsLinked to original sources
PubMed1989

[Problems in the development of immunoglobulin preparations].

With the recent introduction of high-dose intravenous immunoglobulin treatment the preparations have to fulfill more stringent requirements with respect to safety and efficacy. Intravenous tolerance may be achieved by mild fractionation methods in combination with the elimination of anticomplementary aggregates. In early preparations enzymatic digestion or chemical modification of all immunoglobulin molecules was applied. Modern methods try to eliminate the anticomplementary aggregates more specifically by, e.g., precipitation, adsorption or mild acid treatment. Viral safety necessitates an adequate plasma quality in combination with the fractionation method and stringent GMP measures. Full efficacy of a polyvalent immunoglobulin preparation can be achieved by the isolation of the complete antibody spectrum in a native state. The fractionation method has to take care of the wide isoelectric region of the antibody population. The treatment used to achieve intravenous tolerance shall not damage the specific physiological functions of the immunoglobulin molecules. An optimization of the yield guarantees the supply and helps to keep the costs on an acceptable level.

Agammaglobulinemia↗
PubMed1986

Combined active and passive immunotherapy in honeybee-sting allergy.

Five honeybee sting-allergic patients in whom bee venom immunotherapy (VIT) had previously been stopped because of repeated allergic side effects (SE) were resubmitted to bee VIT after pretreatment with beekeeper gammaglobulin. The tolerated bee venom dose was increased five to 800 times after this passive immunotherapy, and the maintenance dose of 100 micrograms of honeybee venom (BV) was reached in all patients after 6 to 15 days of a rush hyposensitization. The IgG response to BV was not suppressed by the beekeeper-gammaglobulin infusion. After 2 to 9 weeks of continued bee VIT, SE recurred in all patients. Therapy had to be stopped in one patient. The other four patients are currently on a maintenance dose of 60 to 80 micrograms. The possibility of a qualitative inferiority of the patients own IgG response was studied by crossed radioimmunoelectrophoresis and IgG subclass analysis. Lack of an IgG response to particular BV components to which IgE was present was demonstrated in three patients. The IgG subclass antibody pattern to BV at the time of recurrence of SE was similar to that found in beekeepers with a prominent IgG4 response. In contrast to beekeepers, however, there was no IgG2 response in patients.

Adult↗
PubMed1985

Influence of heparin and calcium chloride on assay, stability, and recovery of factor VIII.

The influence of heparin alone or in conjunction with calcium chloride on the coagulation assay for factor VIII, on the stability of factor VIII in blood and in plasma, and on the recovery of factor VIII in cryoprecipitate and in an intermediate purity concentrate was investigated. A stabilizing effect of heparin and calcium on factor VIII activity in blood and plasma could be confirmed. We were, however, unable to make use of the higher activity that can, under certain circumstances, be recovered in the cryoprecipitates; this was mainly due to the poor solubility of cryoprecipitates prepared from heparinized blood. Heparin (or the absence of a calcium chelator) also interferes with the recovery of plasma components other than factor VIII.

Calcium Chloride↗
PubMed1984

Isolation of fibronectin under mild conditions.

Fibronectin was isolated from human blood plasma by affinity chromatography on immobilized Physiogel, a plasma expander made by chemical degradation of gelatin. Binding of fibronectin to Physiogel is weaker than to gelatin; elution could therefore be performed under rather mild conditions: at pH 6.5 and 30 degrees C. Loading of the sample at low temperature increases the capacity of the affinity column.

Chromatography, Affinity↗
PubMed1980

Fatty acid patterns during plasma fractionation.

When albumin is prepared from human blood plasma by the cold ethanol method, nonesterified long chain fatty acids present in the plasma do not strictly copurify with albumin. About half of them are lost to the varioius globulin fractions precipitated in the first steps of the fractionation procedure. A different behavior is observed for the short chain fatty acid, caprylic acid. On the other hand, if fractionation of plasma proteins is done by ammonium sulfate precipitation, both long and short chain fatty acids remain with the albumin.

Ammonium Sulfate↗
PubMed1976

Studies on new process procedures in plasma fractionation on an industrial scale. I. Determination of the pH value of ethanol containing protein solutions at low temperatures.

A suitable combined pH electode is evaluated which provides reproducible readings under the extreme conditions of the cold ethanol plasma fractionation procedure. Adequately reproducible correlations are found between the pH measurements in protein solutions with an ethanol content of up to 40% at temperatures as low as -8 degrees C and the determination in diluted samples at room temperature using the standard procedure.

Chemical Fractionation↗
PubMed1976

Studies on new process procedures in plasma fractionation on an industrial scale. II. Experiments in concentrating dilute albumin solutions using hollow fiber ultrafiltration.

Ultrafiltration with a hollow fiber device was studied as an alternative method to the lyophilization or thin-layer distillation techniques in the production of salt-poor, concentrated human albumin preparations for clinical use. A number of process parameters are discussed. Combination of gel filtration and ultrafiltration provides an interesting alternative to the currently used systems.

Chemical Fractionation↗
PubMed1976

Studies on new process procedures in plasma fractionation and industrial scale. III. Removal of precipitates by filtration through a horizontal leaf filter with centrifugal cleaning (Funda filter) as an alternative to tubular-bowl centrifuges.

The possibilities for replacing the time-consuming and labor-intensive centrifugation step in the plasma fractionation process with a filtration technique using filter aids were explored using a Funda filter (pat. Dr. Ing. Hans Müller). The filtration technique proved effective in the separation of the impure plasma fractions. On the other hand, its use in the separation of pure albumin and gamma-globulin fractions appears doubtful.

Centrifugation↗