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F Guillou - One of the best experts on this subject based on the ideXlab platform.

  • Expression of a single betaalpha chain protein of equine LH/CG in milk of transgenic rabbits and its biological activity.
    Molecular and cellular endocrinology, 2001
    Co-Authors: C Galet, C M Le Bourhis, M Chopineau, G Le Griec, A Perrin, T Magallon, J Attal, C Viglietta, L M Houdebine, F Guillou
    Abstract:

    Equine chorionic gonadotropin (eCG) is a heavily glycosylated glycoprotein composed of non-covalently linked alpha- and beta-subunits. eCG possesses the particularity to bind to both LH and FSH receptors in species other than horses and to have a prolonged plasma half-life. All these properties make it of utmost interest for livestock fertilization program. Up to now, the only source of eCG is the serum of pregnant mare. Rabbit mammary gland is considered as a system able to produce Recombinant glycoproteins in sufficient quantity for pharmaceutical use. Here we described the production of a Recombinant single betaalpha chain of eLH/CG in the milk of transgenic rabbit. The construction of a single-chain permits to by-pass the problem of association-dissociation of the subunits. This Recombinant Hormone is greatly expressed (21.7 mg/l) and presents similar in vitro LH and FSH bioactivities. However, betaalphaeLH/CG shows an extremely rapid clearance (approximately 10 min), which could explain the absence of in vivo biological activity. So the rabbit mammary gland is not appropriate for the production of a Recombinant active eLH/CG.

  • Expression of a single βα chain protein of equine LH/CG in milk of transgenic rabbits and its biological activity
    Molecular and Cellular Endocrinology, 2001
    Co-Authors: C Galet, C M Le Bourhis, M Chopineau, G Le Griec, A Perrin, T Magallon, J Attal, C Viglietta, L M Houdebine, F Guillou
    Abstract:

    Abstract Equine chorionic gonadotropin (eCG) is a heavily glycosylated glycoprotein composed of non-covalently linked α- and β-subunits. eCG possesses the particularity to bind to both LH and FSH receptors in species other than horses and to have a prolonged plasma half-life. All these properties make it of utmost interest for livestock fertilization program. Up to now, the only source of eCG is the serum of pregnant mare. Rabbit mammary gland is considered as a system able to produce Recombinant glycoproteins in sufficient quantity for pharmaceutical use. Here we described the production of a Recombinant single βα chain of eLH/CG in the milk of transgenic rabbit. The construction of a single-chain permits to by-pass the problem of association–dissociation of the subunits. This Recombinant Hormone is greatly expressed (21.7 mg/l) and presents similar in vitro LH and FSH bioactivities. However, βαeLH/CG shows an extremely rapid clearance (≈10 min), which could explain the absence of in vivo biological activity. So the rabbit mammary gland is not appropriate for the production of a Recombinant active eLH/CG.

Jacques De Ceaurriz - One of the best experts on this subject based on the ideXlab platform.

  • Detection of continuous erythropoietin receptor activator in blood and urine in anti-doping control
    Haematologica, 2009
    Co-Authors: Françoise Lasne, Laurent Martin, Jean Antoine Martin, Jacques De Ceaurriz
    Abstract:

    Anti-doping control of erythropoietin (Epo) relies on the differentiation by isoelectric profile of natural endogenous Hormone from the Recombinant Hormone used for doping. The first and second generations of Recombinant Epo were detectable in urine.[1][1],[2][2] The third generation, Continuous

  • Detection of isoelectric profiles of erythropoietin in urine: differentiation of natural and administered Recombinant Hormones.
    Analytical Biochemistry, 2002
    Co-Authors: Françoise Lasne, Laurent Martin, Nathalie Crepin, Jacques De Ceaurriz
    Abstract:

    Abstract Erythropoietin (EPO) is normally present in urine at a low concentration (about 1 IU/L, i.e., about 10 ng/L) for a total protein concentration of at least 50 mg/L. A method to study the isoelectric profile of this Hormone from 20-ml urine aliquots without previous purification was developed. This method involves isoelectric focusing of the retentate from ultrafiltered urine. Both the ultrafiltration and the isoelectric focusing required precautionary measures to prevent EPO degradation by the proteases that are present in urine. Because classical immunoblotting gave rise to an unspecific detection of various urinary proteins in the focused retentate, it was essential to use the “double-blotting” process developed to solve this problem. Sufficient sensitivity was achieved using amplified chemiluminiscent detection after the blotting membrane was treated with dithiotreitol. The patterns that were revealed from various urinary samples proved to be highly heterogeneous as they were composed of more than 10 isoforms in a pI range of 3.7–4.7. Clear transformation of the patterns was observed in the case of treatment by the Recombinant Hormone, suggesting that this method can be regarded an efficient tool for indicating Recombinant EPO misuse in sports. It may also open new investigations in the field of physiologic or pathologic exploration.

Robert J. Mattaliano - One of the best experts on this subject based on the ideXlab platform.

  • The effect of posttranslational modifications on the in vitro activity of Recombinant human thyroid-stimulating Hormone.
    Thyroid, 2003
    Co-Authors: Rebecca Sendak, Chandrashekar Ganesa, John J. Harrahy, Roger Théberge, Charles J. Morgan, Edward Cole, Leonard D. Kohn, Robert J. Mattaliano
    Abstract:

    Posttranslational modification can influence the biologic activity of Recombinant proteins. The effects of β-subunit C-terminal truncation, oligosaccharide heterogeneity, and chemical oxidation on the in vitro activity of Recombinant human thyroid-stimulating Hormone (rhTSH) were investigated. β-Subunit C-terminal truncation up to residue 113 did not effect the in vitro activity of the Hormone. The relationship between the heterogeneity of oligosaccharide structures on rhTSH and specific activity of the glycoprotein Hormone was also examined. Oligosaccharide profiles were generated for preparations of rhTSH containing similar sialic acid levels. A weak correlation was observed between relative levels of monosialylated biantennary, bisialylated biantennary, and trisialylated triantennary oligosaccharide species and in vitro activity of the Recombinant Hormone (p < 0.05). To examine the effect of chemically induced methionine oxidation on the activity of rhTSH, the Hormone was treated with tert-butyl hydrop...

C G Winearls - One of the best experts on this subject based on the ideXlab platform.

  • Historical review on the use of Recombinant human erythropoietin in chronic renal failure.
    Nephrology dialysis transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, 1995
    Co-Authors: C G Winearls
    Abstract:

    The success of maintenance haemodialysis in the 1960s was blighted by the problem of anaemia. Treatment with iron, folic acid, androgens and transfusions did no more than minimize its effects. The need for a renewable source of erythropoietin was appreciated very early but the hope took 25 years to realize. Cloning and expression of the human gene was achieved in 1984 and clinical trials planned even before the descriptions of the Recombinant Hormone were published. The Amgen material was tested in parallel studies in Seattle and England and by the end of 1986 the efficacy of Recombinant human erythropoietin (r-HuEPO) given in large intravenous bolus doses in reversing the anaemia of uraemia was established. The benefits were immediately obvious: relief from transfusion dependence was the unequivocal evidence but the effect on 'wellbeing' though subjective was remarkable. Large clinical trials were completed in Europe and the USA so that r-HuEPO was licensed as a therapeutic drug less than two years later. The pilot studies flagged a number of key issues: hypertension, sometimes with encephalopathy, occurred in patients whose blood pressure was labile before treatment; vascular access failure seemed more frequent and hyperkalaemia was thought to reflect less efficient dialysis. Failure to respond focused attention on iron balance as well as on factors such as infection, aluminium, and hyperparathyroidism. A more clear understanding of the pathogenesis of the anaemia of uraemia was made possible by dissection of the specific effects of the exogenous erythropoietin on erythroid function.(ABSTRACT TRUNCATED AT 250 WORDS)

M. Elizabeth Mason - One of the best experts on this subject based on the ideXlab platform.