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Jean-pierre Cartron - One of the best experts on this subject based on the ideXlab platform.

  • RhBG and RhCG, the Putative Ammonia Transporters, Are Expressed in the Same Cells in the Distal Nephron
    Journal of the American Society of Nephrology, 2003
    Co-Authors: Fabienne Quentin, Jean-pierre Cartron, Yves Colin, Dominique Eladari, Lydie Cheval, Claude Lopez, Dominique Goossens, Michel Paillard, Régine Chambrey
    Abstract:

    Two nonerythroid homologs of the Blood Group Rh proteins, RhCG and RhBG, which share homologies with specific ammonia transporters in primitive organisms and plants, could represent members of a new family of proteins involved in ammonia transport in the mammalian kidney. Consistent with this hypothesis, the expression of RhCG was recently reported at the apical pole of all connecting tubule (CNT) cells as well as in intercalated cells of collecting duct (CD). To assess the localization along the nephron of RhBG, polyclonal antibodies against the Rh type B glycoprotein were generated. In immunoblot experiments, a specific polypeptide of Mr approximately 50 kD was detected in rat kidney cortex and in outer and inner medulla membrane fractions. Immunocytochemical studies revealed RhBG expression in distal nephron segments within the cortical labyrinth, medullary rays, and outer and inner medulla. RhBG expression was restricted to the basolateral membrane of epithelial cells. The same localization was observed in rat and mouse kidney. RT-PCR analysis on microdissected rat nephron segments confirmed that RhBG mRNAs were chiefly expressed in CNT and cortical and outer medullary CD. Double immunostaining with RhCG demonstrated that RhBG and RhCG were coexpressed in the same cells, but with a basolateral and apical localization, respectively. In conclusion, RhBG and RhCG are present in a major site of ammonia secretion in the kidney, i.e., the CNT and CD, in agreement with their putative role in ammonium transport.

  • Immunopurification of the Blood Group RhD protein from human erythrocyte membranes.
    Journal of chromatography. B, Biomedical sciences and applications, 1999
    Co-Authors: Sylvie Cochet, Francis Roubinet, Claude Hattab, Antoine Blancher, Jean-pierre Cartron, O Bertrand
    Abstract:

    Rh proteins are membrane proteins encoded by genes at the Blood Group Rh locus. They are of paramount importance in transfusion medicine, but their function is still unknown. Biochemical and biophysical studies of these proteins are scarce since only minute amounts of the very hydrophobic Rh proteins, can be purified from human erythrocytes. Recently, a human monoclonal antibody (LOR-15C9) was described as having the unique property to recognize the Rh30 protein carrying the major Blood Group D specificity (RhD protein), either in a membrane detergent extract or when blotted on a membrane. In this report, we describe one-step purification of the RhD protein from detergent extracts of red cell membranes, based on immunoaffinity chromatography carried out with immobilized LOR-15C9 IgG. The technique yielded RhD protein with high purity which was devoid of other associated proteins (RhAG, CD47, LW and GPB) that comprise the Rh complex in the erythrocyte membrane. By contrast immunoprecipitation performed with the same antibody led to co-isolation of both RhD and RhAG.

  • Molecular analysis of Blood Group Rh transcripts from a rGr variant
    British journal of haematology, 1996
    Co-Authors: I Mouro, Jean-pierre Cartron, Pierre Gane, Yves Colin, Emmanuel Collec, Teresa Zelinski, Caroline Le Van Kim
    Abstract:

    The Rh Blood Group antigens D, Cc and Ee are encoded by two related genes, RhD and RhCE. The RhG antigen (Rh12) is associated with the expression of RhC and/or RhD, except in rare variant red cells. Here we have determined the molecular basis of G expression in the absence of D and C in the r G r phenotype. Nucleotide sequence analysis revealed that the r G allele resulted either from a segmental DNA exchange between part of exon 2 of the Rhce gene and the equivalent region of the RhCE or RhD genes or from a crossing over between positions nt150 and nt178 of the Rhce and RhCe genes. The predicted protein encoded by the hybrid r G gene (c-C-e or c-D-e) carries Ile60, Ser68 and Ser103 (as C and D polypeptides) ; any of these positions appear to be critical in the formation of the G antigen. In addition, Cys16 was found to be important in the phenotypic expression of C.

  • Structural analysis of the Rh-like Blood Group gene products in nonhuman primates
    Immunogenetics, 1995
    Co-Authors: Isabelle Salvignol, Caroline Kim, W W Socha, Patrick Bailly, Y. Colin, J Ruffie, Patrick Calvas, Jean-pierre Cartron, Antoine Blancher
    Abstract:

    Rh-related transcripts present in bone marrow samples from several species of nonhuman primates (chimpanzee, gorilla, gibbon, crab-eating macaque) have been amplified by RT-polymerase chain reaction using primers deduced from the sequence of human Rh genes. Nucleotide sequence analysis of the nonhuman transcripts revealed a high degree of similarity to human Blood Group Rh sequences, suggesting a great conservation of the Rh genes throughout evolution. Full-length transcripts, potentially encoding 417 amino acid long proteins homologous to Rh polypeptides, were characterized, as well as mRNA isoforms which harbored nucleotide deletions or insertions and potentially encode truncated proteins. Proteins of 30–40 000 Mr, immunologically related to human Rh proteins, were detected by western blot analysis with antipeptide antibodies, indicating that Rh-like transcripts are translated into membrane proteins. Comparison of human and nonhuman protein sequences was pivotal in clarifying the molecular basis of the Blood Group C/c polymorphism, showing that only the Pro103Ser substitution was correlated with C/c polymorphism. In addition, it was shown that a proline residue at position 102 was critical in the expression of C and c epitopes, most likely by providing an appropriate conformation of Rh polypeptides. From these data a phylogenetic reconstruction of the Rh locus evolution has been calculated from which an unrooted phylogenetic tree could be proposed, indicating that African ape Rh-like genes would be closer to the human RhD gene than to the human RhCE gene.

  • Localization of the human Rh Blood Group gene structure to chromosome region 1p34.3–1p36.1 by in situ hybridization
    Human Genetics, 1991
    Co-Authors: B. Chérif-zahar, Jean-pierre Cartron, M. G. Mattéi, C. Kim, P. Bailly, Y. Colin
    Abstract:

    A cDNA clone, RhIXb (1384 bp), encoding the entire protein sequence of a human Blood Group Rh polypeptide has been used to map the Rh locus, by in situ hybridization, to the region p34.3–p36.1 of chromosome 1. Two other unrelated cDNA clones, pUCA2 (750bp) and pUCIII (1600 bp), isolated during the cloning procedure of the Rh cDNA were investigated simultaneously, and assigned to chromosome 3p21.1–3p22 (clone pUCA2) and to chromosome 22q12.1–22q13.1 (clone pUCIII).

Sartajbegam N. Pathan - One of the best experts on this subject based on the ideXlab platform.

  • Utility of cord Blood bilirubin as a predictors of significant neonatal Hyperbilirubinemia in healthy term neonate
    International Journal of Contemporary Pediatrics, 2019
    Co-Authors: Rajkumar M. Meshram, Saira Merchant, Swapnil Bhongade, Sartajbegam N. Pathan
    Abstract:

    Background: Clinical jaundice is evident in more than two-third neonates in their early neonatal life. Early identification of neonates at risk might allow early intervention and prevent complication. Objective of the study was to assess the cord Blood bilirubin level as a tool to screen the risk of development of subsequent significant neonatal hyperbilirubinemia in term neonates.Methods: A prospective observational study was conducted over a period of 2 years on 1040 healthy term neonates. Demographic profile, relevant maternal and neonatal information were recorded. Measurement of cord Blood bilirubin, Blood Group/Rh typing and serum bilirubin at the end of 24 & 72 hours was done to predict significant hyperbilirubinemia.Results: Incidence of significant hyperbilirubinemia was 11.53%. Gender, gestational age, mode of delivery and birth weight had no correlation with development of significant jaundice. 800 (76.93%) neonates had cord Blood bilirubin level ≤3.0mg/dl and 240 (23.07%) neonate had cord Blood bilirubin level >3.0mg/dl. Out of 240 (23.07%) neonates with higher cord bilirubin (>3.0 mg/dl), 108 (45%) had significant hyperbilirubinemia at the end of 24 hours with sensitivity 90.00%, specificity 85.65%, positive predictive value 45.00% and negative predictive value 98.50% while 110 (45.83%) neonates were observed with serum bilirubin >17mg/dl at the end of 72 hours with cord Blood bilirubin >3mg/dl with sensitivity 91.67%, specificity 84.52% positive predictive value 45.83% and negative predictive value-98.61% and this difference was statistically significant.Conclusions: Neonates with cord Blood bilirubin level ≤3mg/dl can be safely discharged early whereas neonates with bilirubin >3mg/dl will need close follow up to check for development of subsequent significant jaundice. Hence cord Blood bilirubin levels help to determine and predict the possibility of significant jaundice among healthy term neonates.

  • Utility of Cord Blood Albumin as a Predictors of Significant Neonatal Hyperbilirubinemia in Healthy Term Neonate.
    Asian Journal of Clinical Pediatrics and Neonatology, 2019
    Co-Authors: Rajkumar M. Meshram, Saira Merchant, Sartajbegam N. Pathan
    Abstract:

    Background: Approximately 60% of term and 80% of preterm neonates develop jaundice in first week of life and significant neonatal hyperbilirubinemia occurs in 3-5% of healthy term neonates. Objective:  To assess the cord Blood albumin level as a tool to screen the risk of development of subsequent significant neonatal hyperbilirubinemia in term neonate. Subjects and Methods: A prospective observational study was conducted over a period of 2 years on 1040 healthy term neonates. Demographic profile, relevant maternal and neonatal information were recorded. Measurement of cord Blood albumin, Blood Group/Rh typing and serum bilirubin at the end of 24 & 72 hours was done to predict significant hyperbilirubinemia. Results: A total of 1040 healthy term neonates were enrolled with male to female ratio of 1.4:1. 120 neonates had developed significant hyperbilirubinemia and required phototherapy while 2 of them  did not respond to phototherapy and needed exchange transfusion. Out of 245(23.55%) neonates with low cord albumin level (

Antoine Blancher - One of the best experts on this subject based on the ideXlab platform.

  • Immunopurification of the Blood Group RhD protein from human erythrocyte membranes.
    Journal of chromatography. B, Biomedical sciences and applications, 1999
    Co-Authors: Sylvie Cochet, Francis Roubinet, Claude Hattab, Antoine Blancher, Jean-pierre Cartron, O Bertrand
    Abstract:

    Rh proteins are membrane proteins encoded by genes at the Blood Group Rh locus. They are of paramount importance in transfusion medicine, but their function is still unknown. Biochemical and biophysical studies of these proteins are scarce since only minute amounts of the very hydrophobic Rh proteins, can be purified from human erythrocytes. Recently, a human monoclonal antibody (LOR-15C9) was described as having the unique property to recognize the Rh30 protein carrying the major Blood Group D specificity (RhD protein), either in a membrane detergent extract or when blotted on a membrane. In this report, we describe one-step purification of the RhD protein from detergent extracts of red cell membranes, based on immunoaffinity chromatography carried out with immobilized LOR-15C9 IgG. The technique yielded RhD protein with high purity which was devoid of other associated proteins (RhAG, CD47, LW and GPB) that comprise the Rh complex in the erythrocyte membrane. By contrast immunoprecipitation performed with the same antibody led to co-isolation of both RhD and RhAG.

  • Structural analysis of the Rh-like Blood Group gene products in nonhuman primates
    Immunogenetics, 1995
    Co-Authors: Isabelle Salvignol, Caroline Kim, W W Socha, Patrick Bailly, Y. Colin, J Ruffie, Patrick Calvas, Jean-pierre Cartron, Antoine Blancher
    Abstract:

    Rh-related transcripts present in bone marrow samples from several species of nonhuman primates (chimpanzee, gorilla, gibbon, crab-eating macaque) have been amplified by RT-polymerase chain reaction using primers deduced from the sequence of human Rh genes. Nucleotide sequence analysis of the nonhuman transcripts revealed a high degree of similarity to human Blood Group Rh sequences, suggesting a great conservation of the Rh genes throughout evolution. Full-length transcripts, potentially encoding 417 amino acid long proteins homologous to Rh polypeptides, were characterized, as well as mRNA isoforms which harbored nucleotide deletions or insertions and potentially encode truncated proteins. Proteins of 30–40 000 Mr, immunologically related to human Rh proteins, were detected by western blot analysis with antipeptide antibodies, indicating that Rh-like transcripts are translated into membrane proteins. Comparison of human and nonhuman protein sequences was pivotal in clarifying the molecular basis of the Blood Group C/c polymorphism, showing that only the Pro103Ser substitution was correlated with C/c polymorphism. In addition, it was shown that a proline residue at position 102 was critical in the expression of C and c epitopes, most likely by providing an appropriate conformation of Rh polypeptides. From these data a phylogenetic reconstruction of the Rh locus evolution has been calculated from which an unrooted phylogenetic tree could be proposed, indicating that African ape Rh-like genes would be closer to the human RhD gene than to the human RhCE gene.

Caroline Le Van Kim - One of the best experts on this subject based on the ideXlab platform.

  • Molecular analysis of Blood Group Rh transcripts from a rGr variant
    British journal of haematology, 1996
    Co-Authors: I Mouro, Jean-pierre Cartron, Pierre Gane, Yves Colin, Emmanuel Collec, Teresa Zelinski, Caroline Le Van Kim
    Abstract:

    The Rh Blood Group antigens D, Cc and Ee are encoded by two related genes, RhD and RhCE. The RhG antigen (Rh12) is associated with the expression of RhC and/or RhD, except in rare variant red cells. Here we have determined the molecular basis of G expression in the absence of D and C in the r G r phenotype. Nucleotide sequence analysis revealed that the r G allele resulted either from a segmental DNA exchange between part of exon 2 of the Rhce gene and the equivalent region of the RhCE or RhD genes or from a crossing over between positions nt150 and nt178 of the Rhce and RhCe genes. The predicted protein encoded by the hybrid r G gene (c-C-e or c-D-e) carries Ile60, Ser68 and Ser103 (as C and D polypeptides) ; any of these positions appear to be critical in the formation of the G antigen. In addition, Cys16 was found to be important in the phenotypic expression of C.

Michael J. A. Tanner - One of the best experts on this subject based on the ideXlab platform.

  • Studies on the glycoprotein associated with Rh (Rhesus) Blood Group antigen expression in the human red Blood cell membrane.
    The Journal of biological chemistry, 1994
    Co-Authors: K Ridgwell, David J. Anstee, S. A. C. Eyers, W. J. Mawby, Michael J. A. Tanner
    Abstract:

    The Blood Group Rh antigens are associated with non-glycosylated 30-kDa erythrocyte membrane proteins (the Rh30 polypeptides) and the Rh glycoprotein. We used antipeptide antibodies to study the Rh glycoprotein in human erythrocyte membranes. The Rh glycoprotein was present in Rhnull U+ve cells. However, the N-glycan chain of the Rh glycoprotein in Rhnull U+ve cells was smaller than in normal cells. In contrast, the N-glycan chain of the Rh glycoprotein was larger than normal in glycophorin B-deficient red cells. We suggest that this observation reflects a lower rate of movement of newly synthesized Rh glycoprotein through intracellular membranes to the cell surface in the absence of glycophorin B, and that in normal red cells glycophorin B facilitates the movement of the Rh protein complex to the cell surface. Our results provide evidence for the intracellular interaction of at least three proteins, the Rh glycoprotein, Rh30 polypeptides, and glycophorin B during the biosynthesis and cell surface expression of the Rh complex. These observations are likely to be important for the successful design of expression systems for the Blood Group Rh antigens.

  • Biochemical aspects of the Blood Group Rh (Rhesus) antigens.
    Bailliere's clinical haematology, 1993
    Co-Authors: David J. Anstee, Michael J. A. Tanner
    Abstract:

    Despite their importance in clinical haematology, the details of the structures and possible functions of the proteins associated with Rh antigen expression have only recently begun to emerge. The antigens are carried by a multimeric complex between a M(r) 30,000 polypeptide which is not glycosylated (the Rh30 polypeptide), and a heavily glycosylated glycoprotein (the Rh50 glycoprotein). The N-terminal amino acid sequences of the two types of proteins were determined and used to isolated cDNA clones. The Rh30 and Rh50 proteins are both very hydrophobic membrane proteins, each containing up to 12 membrane spans. The two proteins are homologous in sequence and clearly belong to the same family. They are erythroid-specific and not related to any other known family of proteins. The Rh30 polypeptides are the genetic determinants of Rh Blood Group antigen activity. One polypeptide (Rh30A) is probably associated with CcEe antigen activity, while another (Rh30B) is responsible for the D antigen. The proteins have structures typical of transporters but their functions are still unclear. A number of other red cell membrane proteins (LW, CD47, glycophorin B and Fy) show alterations in red cells lacking Rh antigens (Rhnull). These proteins may have a role in the biosynthesis or function of the Rh30 and Rh50 proteins.