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Biomedical subjects

C M Redman

Publications and source records attributed to C M Redman.

83 records · Page 5Linked to original sources
PubMed1971

Phospholipid metabolism in intact and modified erythrocyte membranes.

Erythrocyte membranes incorporated labeled phosphate from gamma-adenosine triphosphate (AT(32)P) into phosphatidic acid and the polyphosphoinositides. Inositol-(3)H and palmitate-(14)C were also incorporated into the phospholipids but alpha-glycerophosphate-(32)P was not. The incorporation of gamma-AT(32)P into phospholipids was increased when the erythrocyte ghosts were incubated in hypotonic media which lysed the cells. Lysis had little or no effect on the incorporation of inositol-(3)H and palmitate-(14)C into the phospholipids. If erythrocyte membranes were prepared in 1 mM ethylenediaminetetraacetate (EDTA), instead of 1 mM MgCl(2), then the tonicity of the incubating medium did not influence the incorporation of gamma-AT(32)P into the phospholipids. Erythrocyte ghosts, prepared by lysis in water, EDTA, or 1 mM calcium, lead, mercury, zinc, or cadmium, failed to reconstitute when placed in isotonic medium, inasmuch as they did not retain potassium against a chemical gradient. Ghosts prepared by lysis in 1 mM magnesium, barium, or strontium could be reconstituted. Ghosts which failed to reconstitute incorporated more labeled phosphate from gamma-AT(32)P into the phospholipids than did intact or reconstituted ghosts. The larger incorporation of labeled phosphate by leaky ghosts was not due to a greater entrance of gamma-AT(32)P into those cells. Primaquine phosphate and digitonin, at concentrations which are known to cause cells to form smaller vesicles or to lyse cells by removing cholesterol, did not increase the incorporation of labeled phosphate into the phospholipids. It is suggested that the increased metabolism of phospholipids may be involved in a membrane repair mechanism.

Adenosine Triphosphate↗
PubMedDate not supplied

Isolation of Kell-active protein from the red cell membrane.

Kell blood-group-active protein has been isolated by labeling red cell surface proteins with 125I, sensitizing intact cells with anti-K1, anti-K2, anti-K7, or anti-K22, solubilizing the cell membranes, isolating immune complexes, and separating their components by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Each antibody separated a protein of approximately 93,000 daltons. Periodic-acid Schiff (PAS) staining of Kell protein showed that it was glycosylated. When separated under non-reducing conditions, Kell protein had different SDS-PAGE characteristics with protein bands of approximately 85,000 daltons and 115,000 daltons. This suggests that in the red cell membrane Kell protein is complexed with other proteins. Quantitative experiments made with anti-K7, anti-K22, and a mixture of anti-K7 and anti-K22 indicate that both antigen specificities are present in the same molecule. These biochemical data support serological studies which indicate that K22 is part of the Kell system.

Antigens, Surface↗
PubMedDate not supplied

K23. A low-incidence antigen in the Kell blood group system identified by biochemical characterization.

An antibody in the serum of a gravida 4, para 3 woman reacted with red cells from two of her children, her husband, and his mother, but with none of more than 2100 reference red cell samples and blood samples from donors. The reactive antigen was inactivated by 2-aminoethylisothiouronium bromide or dithiothreitol-papain treatment. The antigen was immunoprecipitated from paternal red cells with maternal antibody and shown to migrate by sodium dodecylsulfate polyacrylamide gel electropheresis as a single protein of approximately 93,000 daltons. After transfer to nitrocellulose paper by Western blotting, the protein reacted with a rabbit antibody specific for Kell protein. The chemical inactivation and electrophoretic findings were characteristic of Kell group antigens. The reaction with the rabbit antibody establishes that the "new" low incidence antigen was an epitope on Kell group protein and must be coded for by the Kell gene. It has been designated K23.

Blood Group Antigens↗
PubMedDate not supplied

Comparison of human and chimpanzee Kell blood group systems.

Kell antigens on chimpanzee (Pan troglodytes) red cells were determined using specific human alloimmune and murine monoclonal antibodies. After avoidance of interspecies reactions, chimpanzee red cells were found to react with most Kell system antibodies. The chimpanzees had phenotypes similar to those of humans. The main difference was that all of 27 chimpanzee red cell samples tested were of the K:6, -7, phenotype, while in humans most are K:-6, 7. The most common chimpanzee Kell blood group phenotype was K:-1,2,-3,4,5,6,-7,11,12,13,14, 15,18,19,22. Murine monoclonal anti-K2 and -K14 immunoprecipitated a 97-kD protein from chimpanzee red cells and a 93-kD protein from human red cells. Enzymatic deglycosylation yielded proteins of about 79 kD for humans and 77 kD for chimpanzees. Both human and chimpanzee Kell proteins reacted equally well on Western blots with polyclonal rabbit antibody to human Kell protein, which indicated close homology.

Adult↗
PubMedDate not supplied

Molecular basis for the high-incidence antigens of the Kell blood group system.

BACKGROUND: The Kell blood group system is complex, containing at least 21 antigens. Some antigens are organized in five allelic sets; other, mostly high-incidence antigens, may be independently expressed. In this study, the molecular basis of five high-incidence antigens in the Kell system are described. STUDY DESIGN AND METHODS: Genomic DNA sequences from K:-12 (KEL:-12), K:-18 (KEL:-18), K:-19 (KEL:-19), K:-22 (KEL:-22), and TOU-(KEL:-26) persons were sequenced and compared to those from persons with a common Kell phenotype. RESULTS: The various Kell phenotypes are due to point mutations that encode amino acid substitutions. In KEL:-18, two mutations in the same codon were noted. In the various phenotypes, the following KEL mutations were noted: in KEL:-12: A1763G, His548Arg; in KEL:-18: C508T and G509A, Arg130Trp and Arg130Gln; in KEL:-19: G1595A, Arg492Gln; in KEL:-22: C1085T, Ala322Val; and in TOU-:G1337A, Arg406Gln. A son of one of the two people with the TOU-phenotype was heterozygous, and he also had the G1337A mutation. CONCLUSION: The high-incidence antigens of the Kell blood group system are characterized by point mutations leading to amino acid substitutions. The KEL:-18 phenotype could be due to either of two point mutations in the same codon replacing arginine with tryptophan or glutamine. TOU was confirmed as a Kell system antigen, and the inheritance of the mutation was demonstrated.

Alleles↗