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P Labrude

Publications and source records attributed to P Labrude.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Professor A.-C. Hollande at the School of Pharmacy of Nancy, 1912-1922].

André-Charles Hollande, born in Chambéry in 1881, obtained his pharmacy degree and science doctorate in Lyon and Grenoble. He came to the School of Pharmacy in Nancy in 1912 as director of studies in micrography and lecturer in natural history. During the war, while he was mobilized (1914-1917), he was head of the chemical and bacteriological laboratory of Chambéry and worked on clinical chemistry and bacteriology. Professor of natural history in Nancy in January 1920, professor of bacteriology some months after, he left Nancy for Montpellier in 1922. His research in Nancy was devoted to zoology (cytology of insects), parasitology, bacteriology (discovery of 5 bacterial species), clinical chemistry and technics (determination of simulations, histology), and finally cytology and colorations. He was also pharmacist inspector for the towns of Chaumont (Haute-Marne) and Epinal (Vosges).

Bacteriology↗
PubMed1992

Possible importance of chromatographic purification position in a blood substitute elaboration process.

Purification of hemoglobin (Hb) solutions suggested as oxygen carriers is an imperative necessity. All processes currently used clear out the solutions of almost the totality of impurities that are able to negatively influence the transfusional efficiency of Hb. We have studied the stability (metHb measurement) of Hb purified by DEAE dextran chromatography (Spherodex, 10 mM phosphate buffer, pH 7.20) which eliminates lipopolysaccharides, enzymes and non heminic-proteins ... without denaturing Hb. In spite of the improvements due to this purification method on the transfusional efficiency of non modified Hb solutions, the lack of enzymes involved in the protection of Hb against autooxidation (superoxide dismutase, peroxidase, catalase ...) makes it much more vulnerable to the reagents used during the following chemical processes: pyridoxylation, polymerization or macromolecule binding, thereby leading to an important oxidation to metHb. These observations led us to question the optimal position of purification in a process of modified Hb preparation. We have shown the importance of this chromatographic position in working on pyridoxylated Hb bound to monomethoxypolyoxyethylene. Spherodex chromatography appears to be a very satisfactory purification method, provided it occurs only at the last step of the process. Many authors have not been attentive to this phenomenon which could be found with other Hb modifications. This therefore imposes to study the best place to incorporate a particular purification step into a hemoglobin preparatory procedure.

Blood Substitutes↗
PubMed1992

A potential blood substitute from carboxylic dextran and oxyhemoglobin. II. Physicochemical and physiological assessments. Preliminary results on guinea pig.

The hemoglobin solution covalently linked to dextran benzene tetracarboxylate (dex-BTC) described in Part I, offered the following characteristics: [Hb] = 70 g/l, non modified Hb less than 15%, metHb less than 5%, P50 close to blood value, viscosity and oncotic pressure near to physiological values (37 degrees C). It was biocompatible, stable in plasma, non hypotensive in rat model, non pyrogenic and did not present abnormal toxicity (on mice, according to the french Pharmacopea). Nevertheless, on account of the presence of dextran in the conjugate and due to the literature, we observed an anaphylactoïd reaction in rats consecutive to the injections: absence of hypotension but presence of a massive oedema resulting from an important increase in the capillary permeability with harmful consequences to the vascular retention and survival time. As guinea pigs are insensitive to dextran, we are beginning to assess this conjugate solution in this animal. The first results are very promising: a lack of mortality after large injection, an almost complete vascular retention, a weak urinary loss (only non conjugated Hb), and a plasmatic half-disappearance time close to 7h. Results from haemorrhagic shocks to a final hematocrit less than 0.10 l/l and total and isovolemic exchange transfusions seem to prove a real oxygen-carrying capacity of this new Hb solution.

Animals↗
PubMed1992

A potential blood substitute from carboxylic dextran and oxyhemoglobin. III. Evaluations by perfusion of normal and ischemic guinea-pig heart.

Hemodynamic parameters of six groups of guinea-pig hearts were studied by the working heart technic of Neely. Three groups were respectively perfused with: Krebs-Henseleit, purified native hemoglobin 1gm/dl and hemoglobin conjugated to dextran benzene tetracarboxylate 1 gm/dl. Three other groups were perfused under the same conditions except that after 30 mn of perfusion, 10 mn of total ischemia were produced followed by 30 mn of reperfusion with the previous solutions. All solutions contained 10 g/l of BSA. Hearts perfused with Hb solutions without ischemia or after ischemia show better parameters than with Krebs-Henseleit. These observations suggest that contrary to previously published results, purified Hb and more, dextran-BTC-Hb appear to be perfusable and are less deleterious for heart than saline without hemoglobin.

Animals↗
PubMed1992

[Current research on oxygen carriers for transfusion: hemoglobin solutions and fluorocarbon emulsions].

Although products currently under study are usually called "artificial blood" or "blood substitutes", it concerns only, for the moment, to achieve preparations able to carry and release oxygen to tissues while allowing also a temporary restoration of "blood" volume. The most advanced scopes are related to hemoglobin solutions and fluorocarbons emulsions. The limitations of free hemoglobin impose to modify it. The reestablishment of a normal, even reduced, affinity for oxygen is obtained by the fixation on hemoglobin of a 2,3-DPG substitute whose most known example is pyridoxal phosphate. The enhancement of vascular retention may be achieved by intramolecular cross-linking, intermolecular polymerization or covalent binding of hemoglobin on macromolecules. The two modifications of hemoglobin must be performed successively et numerous possibilities have been proposed. Bovine and recombinant hemoglobins are also promising. Originally and logically, fluorocarbons are synthetic compounds derived from hydrocarbons by an important or maximal substitution of hydrogen by fluorine. The physical properties of these molecules, impose, for transfusion, their emulsification in an aqueous physiological solution. They need an oxygen enriched atmosphere and their storage in tissues is often extended. At present, the most known emulsion is Fluosol DA, a mixture of perfluorodecalin and perfluorotripropylamine. It allowed to realize numerous researches and the proposal of the multiple possible employment for this category of oxygen carriers. The limitations of Fluosol DA led to fluorocarbons under investigation such as F dimethyl bicyclononanes, F methyladamantane, bis (F-butyl) ethene or F-octylbromide. The new hemoglobin solutions and fluorocarbons emulsions start to meet the requirements of potential users.

Blood Substitutes↗
PubMed1991

Assessment of histocompatibility of different hemoglobin solutions using mesenteric perfusion on the small bowel of the male Wistar rat.

Histocompatibility assessment of 70 g/l stroma-free hemoglobin solutions pyridoxylated or not, and purified or not, was carried out using vascular perfusion of the intestine of rats. Mechanical and ultrastructural changes in the organ and the arteriovenous difference of PO2 were compared to those obtained with albumin, gelatin and dextran. Overlapping epithelium conserves its structure in the presence of hemoglobin, whereas it is partially or totally destroyed with the plasma substitutes. Nevertheless, with non pyridoxylated hemoglobin there is a strong detachment of the epithelium from the lamina propria. The intestine, irrigated by the hemoglobin solutions shows efficient peristalsis, but this totally disappears with plasma substitutes. For similar arterial PO2, for all the solutions, the arteriovenous difference was of 100 mmHg for the hemoglobin solutions, whereas they never exceeded 60 mmHg for the plasma substitutes. Hemoglobin pyridoxylation led to an arteriovenous difference significantly superior (p less than 0.001) to those obtained using non modified hemoglobin. With their O2 supply hemoglobin solutions appear able to limit the development of hypoxia in the tissue. The continuation of peristalsis and the weak ultrastructural modifications confirm the slight histological improvement gained when using pyridoxylated hemoglobin. Nevertheless an extravasation appeared constantly, as well as flow reduction during perfusion with the hemoglobin solutions.

Animals↗
PubMed1991

Importance of purification on transfusional efficacy of hemoglobin solutions.

It has only been realized quite recently how important is the purification of hemoglobin solution for use in transfusion and several techniques have been published. We used ion exchange chromatography with which the main "contaminants" (glycoproteins, enzymes, phospholipids) are absorbed by the gel, whereas hemoglobin is not retained. The solutions studied here are non-modified hemoglobin and its homologue pyridoxylated hemoglobin (PLP-Hb). Physico-chemical analyses, usually undertaken to characterize hemoglobin solutions, show no difference before and after purification, except that the enzymatic activity almost disappears. In order to appreciate the benefits of purification, total exchange transfusions were carried out on rats. Without reperfusion, purification of the hemoglobin solution allowed a significantly longer survival time which was even more significant with PLP-Hb solution. Urinary loss did not seem to be affected by purification. With reperfusion in order to compensate these renal losses, PLP-Hb solutions gave survival times up to three days. However, the inevitable death of the animals poses the problem of instability of these purified solutions following enzyme loss.

Animals↗
PubMed1991

Does Tris-HCl effectively participate in transamination during hemoglobin pyridoxylation?

To test whether Tris is required for covalent binding of pyridoxal phosphate (PLP) to hemoglobin, we carried out the reaction in solutions of Tris homologues, carrying a blocked amine function. With the exception of Mono-Tris, these compounds permitted the synthesis of modified hemoglobins with acceptable spectral properties, P50 values, cooperativity and methemoglobin content, refuting Tris HCI participation during hemoglobin pyridoxylation.

Hemoglobins↗
PubMed1991

Physico-chemical and pharmacological comparison of pyridoxylated hemoglobin bound to polyoxyethylene or polymerized by glutaraldehyde.

Two modified hemoglobin solutions were assessed using the same physico-chemical and pharmacological techniques. The first was prepared by covalent binding of monomethoxypolyoxyethylene (MPOE) 1.9 kDa to pyridoxylated hemoglobin (PLP-Hb). The resulting conjugate had a molecular size of 100 kDa (MPOE-PLP-Hb). The solution was cleared of non-fixed MPOE through ion exchange chromatography on Spherodex, thus bringing viscosity and oncotic pressure back to physiological values. The second was prepared by limited polymerization of pyridoxylated hemoglobin with glutaraldehyde (POLY-PLP-Hb). Tangential flow ultrafiltration achieved a satisfactory polymer/oligomer return. Quality controls showed no difference between the solutions. Total isovolemic exsanguinotransfusions in the rat did not help differentiate the two solutions. Hemorrhagic shock (80% of blood volume, rat) gave definitive survival for 8 of the 14 animals tested with MPOE-PLP-Hb (57%) but only 3 of the 8 animals tested with POLY-PLP-Hb (38%). None of the chemical approaches to reduce hemoglobin loss proved any more efficient than another, with the evaluation techniques employed.

Animals↗
PubMed1990

Haemoglobin pyridoxalation in phosphate buffer: comparison of results with those obtained with Tris-HCl buffer.

Most workers studying haemoglobin solutions re-establish a P50 close to physiological values by covalent fixation of pyridoxal phosphate (PLP) using the method first described by Benesch. This is performed with deoxyhaemoglobin in a Tris-HCl buffer, considered to be necessary for transimination. To simplify the chemical procedure of the conjugation of a macromolecule to Hb-PLP we have performed the pyridoxalation in a phosphate buffer. Physico-chemical analysis of pyridoxalated haemoglobin solutions show a slight degradation of the protein, a amount of fixed PLP to the haemoglobin and a right-shift of the dissociation curve similar whether the coupling is performed in the phosphate or the Tris buffer. The pharmacological evaluation by total and isovolumic exchange transfusion in rats, of solutions prepared from both methods of pyridoxalation show identical survival times, vascular persistence and stability of the conjugates. Thus the pyridoxalation takes place with a comparable yield whatever reagent is used, proving that Tris is not essential to haemoglobin pyridoxalation.

Animals↗
PubMed1990

Usual physicochemical criteria provide insufficient evidence that a functional hemoglobin solution can be used for transfusions after storage for 36 months at +4 degrees C.

Hemoglobin solutions will be of clinical interest only if they are easy to use, efficient and can be stored for long periods. While most studies are concerned with hemoprotein improvement (P50 and plasmatic half-life) few deal with long term stability of liquid state solutions. Physicochemical and physiological analyses were carried out on a 70 g/l ready-to-use hemoglobin solution after 1.5, 2.5 and 3 years storage at +4 degrees C, away from light and without any protective additives. The evaluation of hemoglobin stability by tests used in clinical biology shows few structural and functional alterations. However, after 1.5 year total transfusional exchanges carried out on rats cause rapid death, which seems to point to hemoprotein modifications undetected by biological techniques. It therefore appears that physicochemical tests do not provide adequate grounds for claiming that a hemoglobin solution kept for over a year and a half at +4 degrees C can still be used effectively in transfusions.

Blood Preservation↗
PubMed1990

[Hemoglobin niosomes. II. In vitro interactions of plasma proteins and phagocytes].

We have studied the in vitro interactions versus some blood components of the hemoglobin niosomes whose preparation and physicochemical and oxyphoric properties have been published in a precedent paper (this journal, 1989, No. 7, p. 192). This work was devoted to the research of 1) Agglutination phenomena with ABO blood group substances, plasma, some of its components and three plasma expanders, finally main erythrocytic phenotypes. 2) Adsorption of plasma proteins by immunoelectrophoresis. 3) Effects of niosomes on blood coagulation by thromboelastography. 4) Interactions between niosomes and phagocytes by electron microscopy, chemotactic migration, oxygen consumption, superoxide generation and oxydases function. These assays allow to observe and conclude that: 1) The agglutination phenomena are almost constant except with red blood cells. The agglutinates are dissociable by shaking. The agglutination appears to be nonspecific of a niosome component but is not observed with "classical" DPPC-chol-DCP liposomes. 2) Albumin and eventually transferrin are adsorbed at the surface of niosomes but without destabilizing them. 3) The vesicules show no important effects on coagulation factors, the enhancement of clotting time appearing essentially the consequence of blood dilution. 4) Niosomes phagocytosis is important but all the measurements fail to show any cellular metabolism activation: cell oxygen consumption, oxygenated metabolites generation and oxydases activity are not enhanced whatever the "electric" charge or the niosomes/phagocytes ratio used.

Blood Proteins↗
PubMed1989

Protective effect of sucrose on spray drying of oxyhemoglobin.

As far as we know, spray drying has previously not been applied to oxyhemoglobin, undoubtedly because of the sensitivity of oxyhemoglobin to temperature and oxidation. Our experience with freeze drying encouraged us to perform spray-drying trials in order to compare the results of the two methods, in the absence and the presence of protective compounds. Spray drying of hemoglobin without a protective compound led, as in freeze drying, to formation of a percentage of methemoglobin (50%) that makes it unsuitable for transporting oxygen. In the presence of 0.25 M sucrose (optimum) and at 80-100 degrees C, the functional properties of the hemoglobin were well preserved (methemoglobin approximately 4%), and the residual humidity was limited to approximately 3%. Structural investigation by optical circular dichroism confirmed the results obtained by freeze drying: in the presence of an effective protector, the spectra were similar to those of control hemoglobin and the immediate environment of the heme did not undergo any major change. Electron spin resonance absorption bands in all samples were similar for each value of the spectral decomposition factor, g. This suggests that the structure of the heme is not altered by desiccation and that the protector does not penetrate into the heme pocket since it would have disturbed the symmetry of the crystalline field. Fundamentally, these results are equivalent or similar to those observed with freeze drying; since spray drying is a different process of dehydration, the results indicate a lack of specificity in the phenomena of oxidation or of protection affecting hemoglobin.

Chemistry, Pharmaceutical↗