PubMed Health⌕ Search

Biomedical subjects

P Labrude

Publications and source records attributed to P Labrude.

At least 91 records · Page 5Linked to original sources
PubMed1981

Preparation and oxygen binding properties of soluble covalent hemoglobin-dextran conjugates.

Stroma-free hemoglobin solutions present some drawbacks when used as blood substitutes, essentially because the hemoprotein has a low vascular retention, due to its small hydrodynamic volume. Covalent coupling of the protein with dextran derivatives artificially increases its size and affords polymeric conjugates whose oxygen-binding properties (Barcroft's curve, Hill coefficient) depend on the molecular weight.

Chemical Phenomena↗
PubMed1980

[Acquired coagulation inhibitors. 10 cases (author's transl)].

A circulating anticoagulant with antiprothrombinase activity was detected in 10 patients, 4 of whom had systemic lupus erythematosus. Clinically, haemorrhages occurred only in patients with associated thrombopenia; some developed thrombosis. Recalcification time and activated partial thromboplastin time were prolonged in the patients' plasma and in mixed patients' and control plasma. In 5 cases the anticoagulant was isolated by chromatography as IgG or IgM.

Adolescent↗
PubMed1980

[Effect of the addition of albumin on the preservation of hemoglobin solutions lyophilized in the presence of glucose].

In the case of the clinical use of hemoglobin solution, the possibility of storing this preparation in the lyophilized state will be very useful. Freeze-dried preparations containing glucose alone or associated with albumin (25. 50. 75. 100 g/1) have been stored under air in darkness at room temperature or + 4 degrees C. At room temperature, the study has been stopped after one year in consideration of the important oxidation and denaturation of hemoglobin. The samples stored at low temperature have been studied after two years. With glucose alone, freeze-dried hemoglobin has generally a better stability than the four albumin containing preparations in the different assays (methemoglobin and oxyhemoglobin levels, Hill number, shape of the Barcroft's curve). The p 50 and the oxyphoric capacity are always low. Our hypothesis of an enhancement of hemoglobin stability by albumin in presence of glucose is not confirmed; the denaturation is in correspondence with the albumin concentration.

Freeze Drying↗
PubMed1979

Attempts to use carbodiimide (EDCI) to cross-link hemoglobin for transfusions.

The polymerization of hemoglobin for use as a blood substitute and an oxygen carrier would be of interest because high-mol. wt macromolecules would have a longer vascular retention time than the monomer. We found that the molecules resulting from the treatment of hemoglobin with ethyldimethylaminopropylcarbodiimide did not have a higher mol. wt than free hemoglobin and also had a dissociation curve resembling that of monomers, but seemed more stable.

Carbodiimides↗
PubMedDate not supplied

Hemoglobin-based oxygen carrier distribution inside vascular wall and arterial pressure evolution: is there a relationship?

The hemoglobin-based oxygen carriers (HBOC), like dextran-benzene-tetracarboxylate-hemoglobin (Dex-BTC-Hb), which are present at high concentrations in plasma disturb arterial pressure and induce hypertension. To study if the increase of mean arterial pressure (MAP) is due to the presence of cell-free hemoglobin (Hb) inside abdominal aortic wall, we followed on a model of 50% isovolemic exchange transfusion (IET) in anesthetized guinea pigs, the kinetic of Dex-BTC-Hb distribution inside abdominal aortic wall and we investigated the relationship between arterial pressure modifications and modified Hb distribution. The administration of Dex-BTC-Hb induced instantaneously an increase of MAP that reached its maximum (53% of hypertension from baseline) at 17 min after the end of the IET and was maintained maximally up to 30 min. A significantly decrease of MAP (45% of hypertension from baseline) was observed after 60 min and the baseline level was recovered at 180 min. The investigation of tissue at 17 min by confocal microscopy showed the presence of free Hb in or upon endothelial cells (EC) in intima and in vasa vasorum. At 180 min, the free Hb was found in or upon EC and inside all abdominal aortic wall meanwhile MAP recovered its basal value. These results suggest for the first time that Hb in intima seems to induce the hypertension observed upon IET but can not sustain it even if Hb stayed present in intima and in abdominal aortic wall.

Animals↗