Biomedical subjects

B Brimhall

Publications and source records attributed to B Brimhall.

60 records · Page 4Linked to original sources

PubMed1967

Hemoglobin Yakina. I. Clinical and biochemical studies.

Three members of a family who have erythrocytosis and a new hemoglobin, designated hemoglobin Yakima, are described. The abnormal hemoglobin is characterized by the substitution of histidine for aspartic acid at residue 99 in the beta-chain. Of three possible structure-function relations which would account for the increased oxygen affinity of hemoglobin Yakima, only two seem likely. These are: (a) an intrachain shift in the normal relations between the F and G helices and the heme group, or (b) an effect of the substituted side chain at a region of contact between nonpolar residues of the alpha- and beta-chains which favors the oxyhemoglobin quarternary structure.

Aspartic Acid↗

PubMed1966

Hemoglobin Freiburg: abnormal hemoglobin due to deletion of a single amino acid residue.

Structural characterization of a new variant of human hemoglobin (adult), designated hemoglobin Freiburg, indicates the deletion of the valyl residue No. 23 from an otherwise normal beta-chain. The formula may be written (alpha2)beta(2)(23val-0). The abnormal hemoglobin is present with hemoglobin A in the proposita and in two of her three living children, but is not detectable in her parents. We postulate that this variant represents a triplet base deletion which most likely resulted from an unequal crossing-over between two normal betachain loci during meiosis in one of the parents of the proposita.

Adult↗

PubMed1966

Hemoglobin Sphakiá: a delta-chain variant of hemoglobin A2 from Crete.

A new variant of the normal minor component Hb A(2) has been detected in a family that lives in Sphakiá, Crete. Chemical studies of this abnormal hemoglobin, designated Hb A(2) delta Sphakiá, indicates a substitution of the histidyl residue number two of the delta-chain by an arginyl residue.

Adult↗

PubMedDate not supplied

Gamma chain variants in Jamaican newborns.

15,661 cord bloods from Jamaican infants were examined for abnormal hemoglobins using alkaline cellulose acetate electrophoresis for the initial screening, supplemented by acid agar gel electrophoresis for samples exhibiting abnormal hemoglobin bands. Of the 16 electrophoretic variants which were detected, six were fully characterized and found to be: four Hb F Port Royal (alpha2 Ggamma2 125 Glu replaced by Ala) and two Hb F Victoria Jubilee (alpha2Agamma2 80 Asp replaced by Tyr). The Hb F Port Royal samples each constituted about one eighth of the total Hb F as did seven additional samples presumed to be Hb F Port Royal. The infants with this variant exhibited no special hematological characteristics or other consistent associations. Both Hb F Victoria Jubilee samples occurred in somewhat lower proportions of the total Hb F compared with Hb F Port Royal and exhibited an apparent increase of free alpha chains in the whole hemolysate. The data available on detectable gamma chain variants suggest that a specific point mutation may occur in either a HbGgamma or a HbAgamma locus.

Chromatography, Gel↗

PubMedDate not supplied

Hemoglobin British Columbia (alpha2beta2 101(G3)Glu replaced by Lys). A new variant with high oxygen affinity.

Hemoglobin British Columbia was found in an East Indian living in Vancouver, British Columbia, Canada. Its structure was demonstrated to be alpha2beta2 101(G3)Glu replaced by Lys. It has a significant increase in oxygen affinity, decrease in heme-heme interaction, but normal Bohr effect. Unlike Hb Rush (beta101 Glu replaced by Glu), it is as stable as Hb A to heat and alcohol denaturation. By both cellulose acetate electrophoresis and chromatography the undissociated Hb British Columbia moves between Hb S and Hb A rather than behaving like Hb C. However, the dissociated abnormal beta chain behaves like beta C. The substitution is at the alpha2beta2 contact region. Except for a mild erythrocytosis, the propositus has normal hematological findings.

Adult↗

PubMedDate not supplied

Hemoglobin Baylor (alpha2beta281(EF5) leu replaced by Arg)--an unstable mutant with high oxygen affinity.

The amino acid substitution in a new hemoglobin variant, Hb Baylor (alpha2beta281 (EF5) Leu replaced by Arg), has been determined by application of column chromatography and amino acid analysis of the tryptic peptides. The hemoglobin is somewhat unstable and it has a high oxygen affinity. The propositus shows the opposing hematologic effects of these two properties--the instability being associated with increased destruction, and the high O2 affinity with increased production, of erythrocytes.

Adult↗