Robert D. Koler

Red cell age-related changes of hemoglobins AIa+b and AIc in normal and diabetic subjects.

The minor hemoglobin components, hemoglobin AIa+b and hemoglobin AIc, were measured in the 10% youngest and 10% oldest erythrocytes of 15 normal and 14 diabetic subjects. Erythrocyte fractions were obtained by centrifugation in isopyknic concentrations of dextran: 28.5% of 40,000-mol wt dextran yeilded the 10% lightest of young cells, and 30.5% dextran provided the 10% heaviest or old erythrocytes. Both normal and diabetic erythrocytes contain increased amounts of Hb AIa+b and Hb AIc in old as compared to young cells. In normal subjects, young cells contained 1.2+/-0.2%, and old cells contained 1.8+/-0.4% Hb AIa+b. Corresponding values for diabetic cells were 1.7+/-0.6 and 2.6+/-0.9%. Hb AIc increased from 3.1+/-0.8 to 6.0+/-1.1% in normals and from 5.1+/-2.1 to 10.1+/-3.7% in diabetics. The results indicate that both cell age and diabetes are significant determinants of the amounts of Hb AIa+b and Hb AIc.

Hemoglobin Yakima: 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 8l-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 a- and fl-chains which favors the oxyhemoglobin quarternary structure.

Regulation of C-myc expression during growth and differentiation of normal and leukemic human myeloid progenitor cells.

C-myc proto-oncogene transcripts from serially harvested, colony-stimulating activity (CSA)-stimulated, normal progenitor-enriched human bone marrow cells were compared to those of the promyelocytic leukemia cell line HL-60 and to those of freshly obtained human myeloid leukemic cells. During the early culture period both normal and leukemic cells expressed the c-myc oncogene. In normal cells maximal expression occurred after 24 h of culture and did not occur in the absence of CSA. At this time, progranulocytes predominated in the cultured cells. Although cellular proliferation occurred for 96 h in vitro, c-myc expression ceased after 24-36 h. Terminally differentiated cells predominated in these cultures by 120 h. In contrast, although leukemic cells also expressed c-myc in vitro, transcription persisted throughout the culture period and, in the case of HL-60 cells, occurred in the absence of exogenous CSA. We also noted that normal cells with only one diploid gene copy exhibited, after 24 h of culture, only twofold fewer transcripts than did HL-60 cells in which there were 16 myc copies. Furthermore, c-myc mRNA degradation rates were similar in normal cells and in HL-60 cells. We conclude that c-myc transcription is a normal event in granulopoiesis linked to proliferative activity as well as to primitive developmental stage. Furthermore, the most consistent abnormality in leukemic cells in vitro is their failure to suppress transcriptional activity of this gene. We suggest that c-myc transcription in HL-60 cells may be appropriate for cells arrested at that developmental stage and that the amplified genes in HL-60 cells are quiescent relative to c-myc in normal cells at the same differentiation stage. The techniques described herein may be of value in identifying mechanisms by which normal hematopoietic cells suppress c-myc expression and aberrancies of these mechanisms in leukemic cells.

Hemoglobin casper: β 106 (G8) Leu→Pro: A contemporary mutation

Abstract Two unrelated sporadic patients with hemolytic anemia were found to have the same previously undescribed abnormal hemoglobin (β106 Leu → Pro), named for Casper, Wyoming, where the first proband was born. Both were detected because of anemia and splenomegaly associated with intercurrent infections during the first 2 years of life. Progressive anemia and splenomegaly ensued; and both have showed improvement after splenectomy. No abnormal hemoglobin was detected by electrophoresis at pH 8.6 or 6.9. Freshly drawn blood contained slightly increased amounts of methemoglobin and had no gross alteration in heme to globin ratios. Heinz body generation and heat stability tests for an unstable hemoglobin were positive. Oxygen affinity of their whole blood was greater than normal. Acute hemolytic episodes with increased reticulocytosis have occurred both before and after splenectomy as accompaniments of intercurrent infections. The data reported on unstable hemoglobin variants permit a tentative classification according to clinical severity. Contemporary mutations account for the majority of the reported cases with clinical disease.

Hemoglobin Chico [β66(E10)Lys→Thr]: A New Variant with Decreased Oxygen Affinity

Hemoglobin Chico was discovered in an asymptomatic 3-year-old boy when a mild anemia was detected by a routine blood count. Affected individuals in three generations are also mildly anemic. The abnormal hemoglobin amounts to about 45% of the total. It separates from Hb A by cellulose acetate electrophoresis at pH 8.5 with a mobility similar to Hb J but does not separate in citrate ayar at pH 6.2. Stability in isopropanol is slightly decreased. Its structure differs from the normal by the substitution of a threonyl residue for lysyl residue at position 66(E10) of the 8 chain. The P50 of the oxygen equilibrium curve of whole blood at 37°C was 38 torr compared with controls of 27±2 torr. The P50 binding studies of the isolated Hb Chico revealed a unique right shift of the equilibrium curve with an oxygen binding constant (1/P50) about half of normal. The remaining allosteric properties were essentially normal. This significant decrease in oxygen affinity appears to be due to changes in the heme region which ...

Hemoglobin Linkoping [β36 (C2) Pro→Thr] in a Large Finnish Family from Astoria, Oregon, USA

Eleven members of a large Finnish family from Astoria, Oregon were studied because of an erythrocytosis. No abnormality was detected by the usual hemoglobin electrophoretic tests, but an abnormal variant was separated by reverse phase HPLC. All of the affected individuals have an increased oxygen affinity with a P50 for whole blood at 37 degrees C averaging 18 torr. Fifty percent of their hemoglobin was found to have a threonyl residue in place of the normal prolyl residue at position 36 (C2) of the beta globin chain. This abnormality is identical to Hb Linkoping which was recently reported in a Finnish man living in Sweden.

Hemoglobain Willamette. [α2β2 51PRO→APG (D2)] A New Abnormal Huhah Hemoglobain

A hemoglobin variant with the same electrophoretic mobility as employing S was found in three generations of a black family. No clinical symptoms or findings were present in subjects heterozygous for this mutant. Except for target forms of mature erythrocytes, they have no abnormal hematological findings. Structural studies demonstrated a previously under scribed substitution, β51 Pro→Arg, in the abnormal fraction which accounts for about one-third of the total hemoglobin. This fraction is more unstable in vitro at 65° than normal A hemoglobin. Both whole blood and purified abnormal hemoglobin have increased oxygen affinity and a slightly decreased Bohr effect.