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F Schooneman

Publications and source records attributed to F Schooneman.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Experimental study of a model for granulocyte storage].

An efficient granulocytes preservation would allow an easier study of their structure and functions, of granulocytes functional diseases (e.g. chronic granulomatous disease) and an easier use of granulocytes as a clinical tool (e.g. for localizing infections or for transfusions). Unfortunately, granulocytes are nearly impossible to preserve, even in a short-term storage (less than 24 hours). This study proposes an experimental model which could improve in vitro granulocyte functions maintenance. Bicarbonate buffer, glucose, adenosine triphosphate, vitamins C and E, nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate, amikacin, and ampicillin supplementation significantly (p 0.05) improve maintenance of one or several granulocyte functions during storage.

Chemotaxis, Leukocyte↗
PubMed1991

[Storage of granulocytes].

Granulocytes transfusions set numerous problems and are less and less used. The very short maintenance of the granulocyte functions (chemotaxis) limits their use are a clinical tool (e.g. for localizing infections and for transfusions). Neither granulocyte collection by centrifugation methods (continuous or discontinuous flow) nor glucocorticoid premedication significantly alter granulocytes functions (in particular chemotaxis). Liquid preservation methods give better results than cryogenic methods. Optimal storage parameters are a temperature of 22 degrees C and a pH level close to 7.4. Chemotaxis is the most sensitive indicator of granulocyte damages in connection with storage. Bicarbonate buffer, glucose, proteins and reducing agents supplementation significantly improve chemotaxis maintenance. Cryogenic methods are less studied and less used. They allow storage of only little amounts of granulocytes. In conclusion, efficient granulocyte storage (over several days) would allow an easier use of these cells in many fields, but unfortunately, no solution is yet available.

Chemotaxis, Leukocyte↗
PubMed1990

[Determination of C3a and C5a in hemapheresis procedures].

Study of the interface between blood and artificial surfaces reveals numerous undesirable reactions. For example, the formation of biologically active peptides, C3a and C5a (anaphylatoxins), is a result of complement activation via the alternative pathway. It cannot be denied that the reinjection of large quantities of these molecules could be at the origin of serious side effects. We report herein the anaphylatoxin levels found with 9 hemapheresis procedures (4 plasma filtration membranes, 3 systems for platelet collection, 2 plasma treatment techniques (dextran sulfate cellulose column and cascade filtration)). All the filtration procedures generated very high levels of anaphylatoxins, especially C3a. In contrast, the centrifugation systems produced lower levels. However, considerable amounts of C3a were found with the Cobe Spectra and V50 Haemonetics blood cell separators. The anaphylatoxins generated by the primary filter were partially retained by the dextran sulfate column. These high toxin levels enable an assessment of the degree of hemo-incompatibility of these systems. However, it remains difficult to evaluate whether these anaphylatoxins are dangerous or not.

Blood Component Removal↗
PubMed1990

[Efficacy of 2 cholesterol apheresis systems].

A new generation of techniques can be applied to the selective removal of some well-defined molecules from plasma. This is the field of plasma treatment. We investigated the selective removal of LDL cholesterol, by double filtration and dextran sulfate cellulose column plasmapheresis, from 3 to 4 liters of plasma from 4 hypercholesterolemic patients. The extraction rate of Apo A1 lipoprotein in dextran sulfate was less than 25% and Apo B was between 50 and 90%. Cascade filtration gave an extraction rate for Apo A1 between 25 and 50%; the extraction rate for Apo B was about the same as that found using the dextran sulfate procedure. Both techniques decreased the concentrations of coagulation factors (V, VIII and fibrinogen). In conclusion, we obtained good removal of LDL cholesterol with both systems. Dextran sulfate (from Kaneka) was more selective but very expansive. However, we observed side effects with this product that probably result from the release of dextran sulfate from the column.

Cholesterol, LDL↗
PubMed1990

[Development of a technique of immunoadsorption of LDL-cholesterol].

An immunoadsorption system for lowering plasma cholesterol was optimized. Several polyclonal and monoclonal antibodies were compared and the best results were obtained with goat polyclonal antibodies. The optimum quantity of antibodies to be immobilized on the gel was 5 mg/ml. Taking into account two variables, i.e., 1) that the regeneration must be as complete as possible and, 2) that immunoadsorbents must be used several times without a loss of adsorption capacity, desorption was achieved with 0.3 M glycine adjusted to pH 2.8. Antibody release from the immunoadsorbent was determined and can be minimized by glutaraldehyde treatment of the immunoadsorbent. Each phase, adsorption and desorption, respectively, was well-defined and synchronized, so that two columns could be used in parallel in an automated procedure. The kinetics of plasma protein removal demonstrated the efficiency and the specificity of the procedure.

Animals↗
PubMed1990

Study of parameters involved in specific immunoadsorption of apolipoprotein B.

A therapeutic immunoadsorption system on immobilized and anti-apolipoprotein B as a plasma cholesterol lowering procedure was optimized. Several antibodies were compared and highest adsorption capacity was obtained with goat polyclonal antibodies. Optimum quantities of antibodies to be immobilized on the gel and quantities of apo-B to be applied to columns were determined. The amount of antibodies released from immunoadsorbents can be minimized by treatment with a 0.005% glutaraldehyde solution with an acceptable reduction rate of adsorption capacity. Each phase, adsorption and desorption respectively, were well-defined and synchronized so two columns could be used in parallel in an automated procedure. In these conditions, the immunoadsorption system can efficiently, specifically and safely remove cholesterol and has to be subjected to clinical trials.

Animals↗
PubMed1990

'Eccentriplate': a new centrifugal plate for platelet concentrates.

The evaluation of Dideco's Double Ring reveals a sensitive improvement on the Single Ring. This system provides a platelet concentrate of over 4x 10(11) platelets in 75 minutes. It is reasonable to envisage yet shorter and more efficient processes, as suggested by VALBONESI et al. However, considering the platelet transfusion requirements, it would be interesting to have a plastic 5-day preservation closed system.

Blood Component Removal↗
PubMed1989

Toxicity of HPA-23 (ammonium-21-tungsto-9-antimoniate) for normal human myeloid progenitor cells (GM-CFU) in vitro.

HPA-23 is a competitive inhibitor of the RNA-dependent DNA polymerase (reverse transcriptase) of the human immunodeficiency virus (HIV). It may therefore potentially benefit patients with HIV infection. This study aimed at defining the haematopoietic toxicity of this drug and particularly its effects on the normal human granulocyte-macrophage progenitor cells (GM-CFU). Our in vitro studies, in semi-solid agar, have shown an inhibitory effect of increasing concentrations of HPA-23 on colony and cluster formation. This effect is probably dose-dependent. An almost complete inhibition of colony formation was observed at doses of more than 20 micrograms/ml. Regarding cluster formation, a similar although much more progressive inhibitory effect was found. Our experimental data should be extrapolated with caution to clinical situations. However, they must be kept in mind for optimal design of HPA-23 therapy in HIV infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Plasma exchange in dermatomyositis and polymyositis. Retrospective study of 38 cases of plasma exchange].

In order to evaluate the efficacity of plasma exchanges (PE) in dermatomyositis and polymyositis, the case histories of 38 patients, who had undergone plasma exchanges between 1980 and 1986 in 10 French plasmapheresis centers, were studied. Large volume PE were performed in 34 patients after failure of conventional therapy and were part of the initial regimen for the 4 others. The initial activity of the muscle disease was acute in 27 patients and subacute or chronic in 11 cases. Clinical results were evaluated on a functional scale based on changes in muscle force: 24 patients improved (10 appreciably and 14 moderately) and 14 remained unchanged. PE were well tolerated in 23 patients. But side effects occurred in 15 patients, necessitating treatment withdrawal in 4 cases. PE seem to be more effective when the dermatomyositis is acute and evolutive than when it is chronic and insidious. The encouraging results of this exhaustive retrospective study prompt us to set up a prospective randomized trial.

Adolescent↗