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Biomedical subjects

J Saint-Blancard

Publications and source records attributed to J Saint-Blancard.

At least 19 recordsLinked to original sources
PubMed1995

Properties of red blood cell concentrates stored in PAGGS-sorbitol.

The physiological, biochemical, morphological and rheological characteristics of RBC resuspended in PAGGS-Sorbitol were studied over, and beyond, 49 days. The levels of P50 and 2,3-DPG, as well as the concentration of ATP, stayed above acceptable values for longer periods than those described with other Optional Additive Solutions (OAS). Spontaneous hemolysis was kept below 1%, cell morphology, viscosity, deformability and other factors such as pH, the ratio of glucose consumption to lactate formation, the total adenylates and energetic charge indicate that good properties should be seen after 49 days' storage. In vivo survival studies using a double isotope technique showed that at least 75% of those RBC stored in this OAS for 49 days were still in circulation 24 hours after injection. Therefore RBC stored in PAGGS-S can be kept for 49 days with excellent in vivo survival, as well as maintaining DPG levels for up to 3 weeks. Furthermore, a clinical trial in routine conditions for use has been carried out with surgical and medical patients as well as with hemodialysed patients. The results obtained are those that could at least be expected of normal stored blood. As regards RBC/PAGGS-Sorbitol, it would be reasonable to propose a storage period of 49 days in the liquid state.

Adenine↗
PubMed1991

Large scale production of human albumin: three years experience of an affinity chromatography process.

Immobilized Cibacron Blue is a well-known tool for the separation of a number of proteins and enzymes. Among them, human plasma albumin was easily purified from crude plasma and consequently, this approach represents an interesting way for a production scale. Our data describes about three years of experience in the production of human albumin using large columns of immobilized Cibacron Blue. The amount of albumin produced per cycle was about 250 g on a column of about 50 l. Over 500 cycles the final purity of albumin was very high and constant (98-100%). The albumin yield of the chromatographic fractionation was approximately 82%. The column performance remained acceptable when regeneration operations were applied to the sorbent. The long life of the sorbent renders this approach very attractive and economically acceptable for large scale applications.

Chromatography, Affinity↗
PubMed1989

[Optimization of the purification of human plasma fibronectin by double affinity chromatography using gelatin and heparin Trisacryl LS].

The authors described an optimized method of preparation to obtain pure human plasma fibronectin. The new performances related to the chromatographic and concentration steps, where the saving of time is about 40% and the lyophilization step where the saving of energy is also about 40%. The final product is without any less of either physical and biological activities. The size of the columns, the volumes of the chromatographic supports (gelatin and heparin-Trisacryl LS) and the quantity of the treated plasma are very much important and also the quantities of the final product are very increased.

Acrylic Resins↗
PubMed1989

Blocking activity of mite-specific IgG antibodies studied by skin tests.

The aim of the study was to determine whether IgG antibodies from patients on specific immunotherapy could inhibit skin test reactivity of allergens when mixed with them prior to testing. In a preliminary double-blind study, mite extracts were incubated with glycero-saline solution or non-specific IgG and used in testing 15 patients. Wheal and flare diameters produced with the two mite extracts did not differ significantly. In a second double-blind study with 15 other patients, skin tests using mite extracts incubated with either non-specific IgG or specific IgG showed significantly decreased diameters when mite extracts were preincubated with specific IgG. This result, in vivo, confirms the antigen neutralizing capacity of specific IgG demonstrated in vitro.

Adolescent↗
PubMed1988

The RBC morphological dependence of the RBC disaggregability.

The aim of this study was to determine the red blood cell (RBC) disaggregability dependence upon the RBC shape. The study concentrated on stored blood during bank storage and on suspensions of artificially induced echinocytes. Measurements was performed in autologous plasma of hematocrit 0.45 and at constant plasmatic content. Rheological studies using stationary viscometry, nonstationary viscometry and rheoscopy were made in order to assess different stages of the disaggregability process. Whatever the method of measurement used, the morphological interpretation of the results reveal that beyond 75% of echinocytes within the sample, the disaggregation process is altered. The shear stresses required to dissociate the echinocyte aggregates are significantly higher than those required to disaggregate normal RBC rouleaux.

Erythrocyte Aggregation↗
PubMed1987

Pyridoxylated polymerized hemoglobin solution processing. Interest of a membrane molecular fractionation step.

Glutaraldehyde hemoglobin polymerization gives too many high polymers, resulting in a too viscous solution. We describe here an alternate method leading to superior results, as compared to the classical one. This method includes a molecular fractionation step using a tangential flow ultrafiltration that secondarily lowers the unpolymerized tetramer's content of a mildly polymerized, pyridoxylated hemoglobin solution (Pyr-Poly Hb). This leads to an adequately polymerized product with a lesser high polymer content, implying a lower viscosity. We thus obtain a pyridoxylated, polymerized molecular fractionated solution presenting suitable features as a blood substitute: A 7.5 g% hemoglobin 2 g% albumin solution had a 16% unpolymerized tetramer's ratio, a 1.8 mPas viscosity, a P50 of 2.8 kPa, a Hill coefficient of 2.1, a binding coefficient of 1.3 mL/g, a colloid osmotic pressure of 2.4 kPa, and a methemoglobin concentration of 3% Male-Sprague-Dawley rats undergoing an isovolumic blood exchange with this Pyr-Poly Hb solution, down to a 2% hematocrit, present a mean survival time of 20 h.

Animals↗
PubMed1987

[Functional adjuvant for stored red blood cells: ascorbate or oxalate?].

In stored blood cells the p50 and the 2,3-DPG concentration drop rapidly. To compensate the functional resultant weakness, many different additives have been proposed, in particular ascorbate, which is very unstable, and ascorbate-2-phosphate (AsP), which is a little more stable. We have studied the effect of two commercially available AsP whose impurity content was different. It was found that the more the substance was impure the more it was effective. This led as to doubt the effectiveness of ascorbate itself and to try the impurity (oxalate) with which we have obtained the results published with AsP.

Ascorbic Acid↗
PubMed1987

[Purification of human plasma fibronectin by double affinity chromatography on gelatin and heparin-Trisacryl].

In this work the human plasma fibronectin was purified by affinity chromatography using a tandem column system. The first affinity column was filled with gelatin-Trisacryl whereas the second one contained heparin-Trisacryl. This double affinity chromatography demonstrated its high efficiency in term of purity and yield. Several analytical methods (electrophoresis, immunoelectrophoresis, F.P.L.C. and adhesion assay on cultured eucaryotic cells) evidenced in fact the high purity of the preparation as well as its biological behaviour in term of cell adhesion and spreading. The performances of the sorbents used facilitate the scaling up when large quantities of FNP are needed.

Acrylic Resins↗
PubMed1983

[Changes in the rheologic properties of various samples of blood preserved at +4 degrees C].

Apparent stationary viscosity, viscoelasticity and thixotropy measured with a Couette viscosimeter have been determined on blood samples stored in eight anticoagulant and/or preservative solutions. All the results as well as those obtained in a previous morphological study show clearly the advantages of the SAG or PAGGS storage processes. It is observed that the rheological parameters of RBC stored in protein poor media are, between the 30 th and 35 th days, identical on CPD at the first week and with that measured in CPD concentrates between second and third week (for a same hematocrit value). We want to emphasize that the erythrocytes stored in these new media retain for a long time their ability to circulate in the capillary system.

Adenine↗