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At least 163 records · Page 9Linked to original sources
PubMed1994

Locus-Control-Region-Coupled Beta (S)(Antilles)- and Alpha(2)-Hemoglobin Genes Select for High Alpha(2)-Hemoglobin Expression in Adult Transgenic Mice.

Two transgenic lines of mice were produced which contained the beta(S)(Antilles)- and alpha(2)-hemoglobin genes tandemly coupled to the 'micro' locus control region (&mgr;LCR). The &mgr;LCRbeta(S)(Antilles)alpha(2)-hemoglobin transgenic mice expressed high levels of alpha(2)-hemoglobin while beta(S)(Antilles)-hemoglobin expression was virtually undetectable. Abundant alpha(2)-hemoglobin protein was observed in the blood of transgenic mice, while beta(S)(Antilles)-hemoglobin chains could not be detected. Transgenic red blood cells had substantially decreased sensitivity to osmotic lysis. Attempts to produce homozygotes containing the transgene were unsuccessful. The phenotype of these mice closely resembles that of beta-thalassemic mice. The &mgr;LCRbeta(S)(Antilles)alpha(2) transgenic mice demonstrate that if the &mgr;LCR is coupled to the beta(S)(Antilles)- and alpha(2)-hemoglobin genes in tandem, only the distal alpha(2)-hemoglobin gene is selected for expression to significant levels in adult mice. These results support a reciprocally competitive model for LCR-hemoglobin developmental switching. Copyright 1994 S. Karger AG, Basel

Journal Article↗
PubMed1988

Amino acid sequences of hemoglobins I and II from root nodules of the non-leguminous Parasponia rigida-rhizobium symbiosis, and a correction of the sequence of hemoglobin I from Parasponia andersonii.

The amino acid sequence of hemoglobins I (pI 6.15 as oxyhemoglobin) and II (pI 5.64 as oxyhemoglobin) from the nitrogen-fixing root nodules of Parasponia rigida have been determined by protein sequencing. The sequence of hemoglobin I (pI 6.16, as oxyhemoglobin) from Parasponia andersonii was re-examined and the corrected primary structure, now in agreement with that predicted from the DNA sequence, is reported. The three Parasponia hemoglobins contain 161 amino acid residues (Mr approximately equal to 18,700 including the heme) with a single cysteine residue and five methionine residues. The N-terminal serine is blocked by an acetyl group. The primary structure of the Parasponia hemoglobins is highly conserved. Hemoglobins I from the two species of Parasponia are identical; both show microheterogeneity at position 30 (Asp/Glu substitution) and hemoglobin I from P. rigida shows microheterogeneity at position 150 (Ala/Val) while hemoglobin I from P. andersonii has only an Ala at 150. P. rigida hemoglobin II shows no microheterogeneity at these positions, having Asp and Val residues respectively, and it contains a single amino acid change of a Gln for an Arg at position 85, which accounts for the 0.5 unit difference in isoelectric point observed between hemoglobins I and II. The sequence data are consistent with allelic heterogeneity at a single locus rather than different genes.

Amino Acid Sequence↗
PubMed2002

[A simple lightweight device for measurement of low hemoglobin concentrations: the Hemo Cue Low Hemoglobin Photometer].

To determine low hemoglobin concentrations in the washed fluid is useful for calculation of blood loss and that in the supernatant is also useful for evaluation of hemolysis during extracorporeal circulation or in the blood preparations. The HemoCue Low Hemoglobin Photometer is a new lightweight device, which is easily movable anywhere and is able to determine hemoglobin concentration in low ranges (0.03-3.00 g.dl-1). We investigated the accuracy and reliability of the HemoCue Low Hemoglobin Photometer. Blood samples were diluted with saline containing heparin into six tubes. The hemoglobin concentrations of each diluted sample were measured by the HemoCue Low Hemoglobin Photometer, and were compared with the calculated values. A high positive correlation was found between the values measured by the HemoCue Low Hemoglobin Photometer (Y) and the calculated values (X); Y = 1.047 X, r = 0.999, P < 0.0001. It took only 11-54 seconds (mean value: 31.4 seconds) for the measurement. It is concluded that the HemoCue Low Hemoglobin Photometer is a reliable and useful device for measurement of low hemoglobin concentration.

Evaluation Studies as Topic↗
PubMed2001

Hemoglobin of the Antarctic fishes Trematomus bernacchii and Trematomus newnesi: structural basis for the increased stability of the liganded tetramer relative to human hemoglobin.

Hemoglobins extracted from fishes that live in temperate waters show little or no dissociation even in the liganded form, unlike human hemoglobin (HbA). To establish whether cold adaptation influences the tendency to dissociate, the dimer-tetramer association constants (L(2,4)) of the carbonmonoxy derivatives of representative hemoglobins from two Antarctic fishes, Trematomus newnesi (Hb1Tn) and Trematomus bernacchii (Hb1Tb), were determined by analytical ultracentrifugation as a function of pH in the range 6.0-8.6 and compared to HbA. HbA is more dissociated than fish hemoglobins at all pH values and in particular at pH 6.0. In contrast, both fish hemoglobins are mostly tetrameric over the whole pH range studied. The extent of hydrophobic surface area buried at the alpha(1)beta(2) interface upon association of dimers into tetramers and the number of hydrogen bonds formed are currently thought to play a major role in the stabilization of the hemoglobin tetramer. These contributions were derived from the X-ray structures of the three hemoglobins under study and found to be in good agreement with the experimentally determined L(2,4) values. pH affects oxygen binding of T. bernacchii and T. newnesi hemoglobins in a different fashion. The lack of a pH effect on the dissociation of the liganded proteins supports the proposal that the structural basis of such effects resides in the T (unliganded) structure rather than in the R (liganded) one.

Animals↗
PubMed1983

An immunohistochemical study of hemoglobin A, hemoglobin F, muramidase, and transferrin in erythroid hyperplasia and neoplasia.

The bone marrow biopsy specimens of 35 patients with benign and malignant erythroid hyperplasias were examined for the presence of hemoglobin A, hemoglobin F, muramidase (lysozyme), and transferrin, using an indirect immunoperoxidase method (PAP) on Zenker's-fixed paraffin-embedded bone marrow biopsy specimens and particles. Five cases of each of the following entities were studied: erythroleukemia and erythremic myelosis, acute granulocytic leukemia with maturation (FAB M2), polycythemia rubra vera, myeloproliferative syndrome in childhood, megaloblastic anemia (B12 and folate deficiency), erythroid hyperplasia (regenerating bone marrow and hemolytic anemia), and Ph' chromosome positive chronic granulocytic leukemia. Hemoglobin A was present in both the early and late erythroid precursors in all conditions. Hemoglobin F was the predominant hemoglobin in early erythroblasts of pernicious anemia and in both early and late erythroid elements in erythroleukemia and erythremic myelosis. Small quantities of hemoglobin F were present in a few isolated clusters in other conditions. Staining for hemoglobin F may be useful in identifying immature erythroid precursors and in distinguishing some cases of dysplastic erythroid hyperplasia from neoplasia. Additionally, these findings suggest that the maturational switch in hemoglobin synthesis operates with distinct pathways under different conditions.

Bone Marrow↗
PubMed1973

Hemoglobin brigham (alpha2Abeta2100 Pro--Leu). Hemoglobin variant associated with familial erythrocytosis.

Erythrocytosis associated with the presence of a hemoglobin with increased oxygen affinity has been reported for 10 hemoglobin variants, most of which demonstrate altered electrophoretic mobility. Several members of a family were found to have erythrocytosis, and both the whole blood and the hemoglobin exhibited increased oxygen affinity. Phosphate-free hemoglobin solutions had a normal Bohr effect and reactivity to 2,3-diphosphoglycerate. The electrophoretic properties of the hemoglobin were normal, but on peptide mapping of a tryptic digest of the isolated beta-chains, a normal betaT11 peptide and an abnormal betaT11 with greater R(f) were seen. Analysis of the abnormal peptide showed the substitution of leucine for the normal proline at beta100 (helical residue G2).The hemoglobin variant, designated Hb Brigham, serves to emphasize the necessity for detailed evaluation of the structure and function of hemoglobin in familial erythrocytosis even with electrophoretically "normal" hemoglobin.

Amino Acids↗
PubMed1967

The electrophoretic pattern of hemoglobin in newborn babies, and abnormalities of hemoglobin F synthesis in adults.

On routine electrophoretic analyses on filter paper and starch gel in an alkaline or neutral medium, no abnormal hemoglobin fractions were found in the blood of 600 newborn infants or their mothers. Trace amounts of hemoglobin Barts were noted in many of the blood samples from newborns when the starch gels (phosphate buffer pH 7.0) were stained with a benzidine/H(2)O(2) reagent. In one infant, precocious cessation of synthesis of hemoglobin F was postulated to account for the small amounts of this hemoglobin found in a cord-blood specimen. Analysis of 15,000 blood samples from adults revealed two instances in which the hemoglobin F level was 20 and 35%, respectively. The former was attributed to a hereditary persistence of hemoglobin F, while the latter was associated with acute leukemia.In an addendum, the finding of an infant with an abnormal hemoglobin variant, resembling in many of its properties hemoglobin F Texas, is reported.

Adult↗
PubMed1980

Solubilization of hemoglobin S by other hemoglobins.

The polymerization of mixtures of Hb S with hemoglobins A, A2, and F has been investigated by analysis of the proportions of S and non-S hemoglobin both in the supernate and in the pellet after centrifugation. In all cases the non-S hemoglobin was incorporated into the polymer even in the absence of hybrids in the order A > A2 > F. The solubility of Hb S is substantially increased by the other hemoglobins, especially by Hb F, which would account for its antisickling effect. It appears that the excluded volume effect of the other hemoglobin on Hb S is largely counterbalanced by the solubilizing effect arising from the interaction between the two hemoglobins in solution. The ability of hybrid hemoglobins to gel was demonstrated directly with tetramers in which alpha beta s dimers were covalently linked to alpha beta A, alpha delta A2, and alpha gamma F dimers.

Centrifugation↗
PubMed1981

Interaction of organic phosphates with bovine hemoglobin. II. Oxygen binding equilibria of newborn and adult hemoglobin.

We investigated oxylabile H+ binding and pH dependent oxygen binding of adult and newborn bovine hemoglobin as influenced by the organic phosphates 2,3-disphosphoglycerate (DPG), adenosine-5'-triphosphate (ATP), and myoinositol hexaphosphate (IHP). The oxygen affinity of newborn bovine hemoglobin is higher than that of adult hemoglobin over a pH over a pH range of 6.5 to 8. Both DPG and IHP decrease the oxygen affinity of adult bovine hemoglobin. IHP not only decreases the oxygen affinity, but also reduces the apparent cooperativity, whereas DPG does not affect cooperativity. The rise in logP50 upon addition of DPG is about equal for adult and newborn bovine hemoglobin: at pH 7.0 we find delta logP50 values of 0.14 and 0.13 respectively upon addition of a fivefold excess of organic phosphate. This agrees with the identical nature of the presumed organic phosphate binding site in these two hemoglobins, but contrasts with the situation in man: newborn human hemoglobin is much less influenced by organic phosphates than adult human hemoglobin.

Aging↗
PubMed1985

Uptake of iron from hemoglobin and the haptoglobin-hemoglobin complex by hemolytic bacteria.

The abilities of Staphylococcus aureus and Streptococcus pyogenes to remove iron from mouse 59Fe hemoglobin that was either in free form or complexed with human haptoglobin, were evaluated. 59Fe hemoglobin from the amphibian Taricha granulosa was also used in free form or complexed with the amphibian's hemoglobin-binding proteins. Contrary to what was reported from a study using pathogenic Escherichia coli, haptoglobin failed to exhibit a bacteriostatic influence when complexed with hemoglobin. In our study, more 59Fe was removed by the bacteria from the haptoglobin-hemoglobin complex than from free mouse hemoglobin. The hemoglobin and hemoglobin-plasma protein complexes of Taricha were stripped of 59Fe at similar rates and extents by both bacterial species.

Amphibians↗
PubMed1983

Demonstration of a minor hemoglobin with modified alpha chains and additional modified hemoglobins in normal and diabetic adults.

We have attempted to separate various hemoglobins in 10 normal and 11 diabetic persons by Bio-Rex 70 chromatography at 4 degrees C with an exponentially increasing sodium phosphate gradient. Minor hemoglobins, namely AIa1, AIa2, AIb1, AIb2, AIb3, AIc, AId1, AId2 and AId3, have been separated and eluted in that order. Most of these minor hemoglobins were newly observed and could not be detected by the previous chromatographic techniques. On the basis of colorimetric assay protein-bound ketoamine was present in all the minor hemoglobins, which was confirmed by chromatographic separation of hemoglobins after reduction with NaB3H4. All the minor hemoglobins, with the exception of Hb AIa1, HbIa2, and Hb AIb1, showed a 2-fold increase in the diabetic patients. Hb AIc (5.0% in normals; 9.0% in diabetics) and Hb AId3 (1.9% in normals; 3.2% in diabetics) were present in the largest amounts. Both Hb AId3 and Hb Ao showed a decrease in oxygen affinity in the presence of 2,3-diphosphoglycerate, whereas Hb AIc showed no effect. Separation of globin chains by cellulose acetate electrophoresis at pH 8.6 showed that the cathodal mobility of the alpha chains of Hb AId3 was slower than those of Hb Ao. Glycosylation of Hb with [14C]glucose followed by separation of hemoglobins by two Bio-Rex 70 chromatographic methods indicated that the minor Hb formed by glycosylation of the alpha-chain amino-terminus was separated from Hb Ao, while the minor hemoglobins formed by the glycosylation of epsilon-NH2 groups chromatographed with Hb Ao.

Chromatography, Ion Exchange↗