Hemoglobin C Trait in Saskatchewan

In the beta chain of normal adult hemoglobin, the amino acid residues in positions six and seven are glutamic acid. In hemoglobin C, lysine replaces the glutamic acid residue in position six. Two hemoglobin variants have been described in which lysine replaces the glutamic acid residue in position seven.During a search for abnormalities of hemoglobin synthesis detectable by conventional electrophoretic techniques, some 20,000 blood samples were screened from the population of Saskatchewan. Two specimens gave an electrophoretic pattern of hemoglobins A and C. The abnormal hemoglobin was purified and “finger printed” and found to be the same as classical hemoglobin C (i.e. α₂β₂ 6 glu → lys). Both specimens had originated from healthy blood donors, one a Ghanaian student and the other a young white man of immigrant Irish-Scottish parents living near Saskatoon.     

Hemoglobin variation in macaques

A total of 1,333 hemolysates obtained from six different species of macaques,M. fuscata, M. cyclopis, M. mulatta, M. speciosa, M. nemestrina, andM. irus, were examined by starch gel electrophoresis. Three major hemoglobins, tentatively designated S, F, and P, and one minor component were found among the samples, in which P and a minor component were observed only in some samples ofM. irus. The hemoglobin types observed and their incidence in each species agreed, on the whole, with results reported by earlier workers. However, in addition to marked differences among macaque species, there existed striking geographical differences in the distribution of hemoglobin components within the same species. The distribution of hemoglobin types observed among the species are presented, together with the results of the determination of hemoglobin concentration in a two-band type and those of the alkali-resistant pigment of the macaques.     

Hemoglobin abnormalities in neoplastic hematological disorders

Fetal hemoglobin (F) and hemoglobin A₂ were estimated in 35 patients with malignant hematological disorders. In 9 out of 10 patients with morphological and cytochemical features of acute myeloblastic leukemia the hemoglobin F was greater than 2%. Of the other 25 patients investigated only one patient with polycythemia rubra vera had a hemoglobin F level of more than 2%. Estimation of fetal hemoglobin may be of value in the classification of acute leukemias and the increased level observed probably reflects disturbed hemoglobin synthesis in the acute myeloblastic type.     

Hemoglobin of mice with radiation-induced mutations at the hemoglobin loci.

Chemical analyses were done on the abnormal hemoglobins of five (101 × SEC)F₁ offspring of X-irradiated adult SEC mice to determine which hemoglobin genes were expressed in each hemoglobin variant. Three offspring of irradiated SEC males did not express either of the two kinds of α-chains normally found in all SEC mice. The deficient α-chain synthesis caused these mice to exhibit an α-thalassemia similar to human α-thalassemia. Scanning electron microscopy was used to show that many erythrocytes of mice with α-thalassemia have bizarre shapes; e.g. many erthrocytes appeared flattened or had thorny projections (acanthocytes). One mutant with a tandem duplication of a segment of chromosome 7 (site of locus determining β-chain structure) produced twice as much SEC as 101 β-chain polypeptides. One mutant that probably arose by non-disjunction of chromosome 7's in its unirradiated 101 mother and loss of chromosome 7 from the gamete of its irradiated SEC father did not express the SEC β-chain gene.     

Ocular Manifestations of Hemoglobin S-C Disease

Three patients with hemoglobin S-C disease, all with ocular lesions, were studied and contrasted with four other patients who had predominantly either hemoglobin S or C but no ocular lesions. Attention is drawn to the diagnostic value of hemoglobin electrophoresis in such cases. With this technique a diagnosis of hemoglobin S-C disease was made in a patient previously thought to the “Eales'' disease”; one sister was found to have asymptomatic hemoglobin S-C disease and unsuspected early ocular lesions. The number of persons in Canada with hemoglobinopathies is increasing. Awareness of an association between abnormal hemoglobins and ocular disease may lead to the recognition of an unsuspected blood disorder or of an unsuspected retinopathy.     

Absence of messenger RNA and gene DNA for β-globin chains in hereditary persistence of fetal hemoglobin

The relative amounts of α- and β-globin mRNA and globin gene DNA were measured in reticulocyte RNA and lymphocyte DNA of an individual with homozygous hereditary persistence of fetal hemoglobin whose red blood cells contain 100% fetal hemoglobin (Hb F: α₂γ₂). Molecular hybridization assays used as probes full-length DNA copies of human α- and β-globin messenger RNA. The results of these hybridization assays demonstrated the expected amounts of α-globin mRNA and gene DNA, but absence of β-globin mRNA and absence of β-globin gene DNA. In the individual studied, hereditary persistence of fetal hemoglobin is associated with total deletion of the β-globin structural gene.     

Inhibitory effect of deoxyhemoglobin A2 on the rate of deoxyhemoglobin S polymerization.

From a consideration of the primary sequence of hemoglobin A₂ and the reported 5 å molecular contacts between deoxyhemoglobin S molecules in a crystal, it is predicted that hemoglobin A₂ might act as an inhibitor of the polymerization of deoxyhemoglobin S in a manner similar to hemoglobin. F. This has been tested experimentally by measuring the rate of change of the transverse water proton relaxation times (T₂) in equimolar mixtures of hemoglobin S and one of the non-gelling hemoglobins A, F or A₂. Hemoglobins A₂ and F have far more pronounced inhibitory effects on the rate of polymerization than does hemoglobin A. These molecules contain several amino acid differences from hemoglobin A beta chains which are located in the 5 Å molecular crystal contacts and these altered crystal contacts result in a much stronger inhibition of the rate of polymerization. Since hemoglobin A₂ is a normal hemoglobin found in small amounts in all adult red cells, increased delta chain synthesis may have potential importance in therapy for sickle cell disease.     

Effect of Glycation of Hemoglobin on its Interaction with Trifluoperazine

Trifluoperazine (TFZ), a phenothiazine drug, penetrates into human erythrocytes and releases oxygen by interaction with hemoglobin. TFZ-induced oxygen release from hyperglycemic erythrocytes isolated from diabetic patients is considerably less compared to that from the cells of normoglycemic individuals. In diabetes mellitus, hemoglobin is significantly glycated by glucose. Non-glycated hemoglobin, HbA₀ and its major glycated analog, HbA_1c have been separated from the blood samples of diabetic patients. TFZ releases considerable amount of oxygen from HbA₀, but very little from HbA_1c. Spectrofluorimetric studies reveal that TFZ forms excited state complexes with both HbA₀ and HbA_1c. Titration of HbA₀ with TFZ in a spectrophotometric study exhibits two isosbestic points. Similar experiment with HbA_1c causes gradual loss of the Soret peak without appearance of any isosbestic point indicating a possibility of heme loss during interaction, which is also supported by gel filtration experiment and SDS-PAGE experiment followed by heme staining. The results suggest that drug action on hemoglobin is influenced by glycation-induced structural modification of the protein.     

Hemoglobin Roseau-Pointe a Pitre alpha 2 beta 2(90) (F6) Glu----Gly: a new hemoglobin variant with slight instability and low oxygen affinity

A Dominican neonate carrying a new abnormal hemoglobin, hemoglobin Roseau Pointe-à-Pitre alpha 2 beta 2(90)(F6) Glu----Gly, was detected in Guadeloupe during application of a cord blood screening program. This variant behaved in isoelectrofocusing as an Hb D, and displayed instability and low whole blood oxygen affinity. In the affected family it was present, either isolated, or in association with a beta+ thalassemia trait.     

Oxidative Stress-Induced DNA Damage and Repair in Human Peripheral Blood Mononuclear Cells: Protective Role of Hemoglobin

Background

DNA repair is a cellular defence mechanism responding to DNA damage caused in large part by oxidative stress. There is a controversy with regard to the effect of red blood cells on DNA damage and cellular response.

Aim

To investigate the effect of red blood cells on H₂O₂-induced DNA damage and repair in human peripheral blood mononuclear cells.

Methods

DNA breaks were induced in peripheral blood mononuclear cells by H₂O₂ in the absence or presence of red blood cells, red blood cells hemolysate or hemoglobin. DNA repair was measured by ³H-thymidine uptake, % double-stranded DNA was measured by fluorometric assay of DNA unwinding. DNA damage was measured by the comet assay and by the detection of histone H2AX phosphorylation.

Results

Red blood cells and red blood cells hemolysate reduced DNA repair in a dose-dependent manner. Red blood cells hemolysate reduced % double-stranded DNA, DNA damage and phosphorylation of histone H2AX. Hemoglobin had the same effect as red blood cells hemolysate on % double-stranded DNA.

Conclusion

Red blood cells, via red blood cells hemolysate and hemoglobin, reduced the effect of oxidative stress on peripheral blood mononuclear cell DNA damage and phosphorylation of histone H2AX. Consequently, recruitment of DNA repair proteins diminished with reduction of DNA repair. This suggests that anemia predisposes to increased oxidative stress induced DNA damage, while a higher hemoglobin level provides protection against oxidative-stress-induced DNA damage.     

Markedly Low Hemoglobin A1c in a Patient with an Unusual Presentation of ß-Thalassemia Minor

ObjectiveTo describe very low hemoglobin A_1c levels in a patient with type 2 diabetes mellitus and an unusual presentation of β-thalassemia minor.MethodsWe present the clinical and laboratory findings of the study patient.ResultsA 64-year-old African American man with type 2 diabetes mellitus was referred to the endocrinology clinic with a hemoglobin A_1c level of 1.6% despite elevated blood glucose concentrations. A red blood cell survival study with chromium-51 revealed that he had a reduced erythrocyte life span less than 25% of normal. He also had a markedly elevated reticulocyte count ranging from 236 to 534 x 10³/μL (reference range, 25-75 x 103/μL). The laboratory findings, which are not characteristic of ß-thalassemia minor, could be the cause of the markedly low hemoglobin A_1c in this patient.ConclusionsAlthough rare, when associated with marked erythrocyte turnover, β-thalassemia minor can lead to a severe reduction in HbA_1c levels. In this scenario, glycemic control is best assessed by measuring fructosamine. (Endocr Pract. 2010;16:89-92)     

Hemoglobin Koya Dora: high frequency of a chain termination mutant.

Approximately 10% of the members of the Koya Dora tribe from Andhra Pradesh (India) carry an alpha chain hemoglobin variant, Hb Koya Dora (Hb KD), usually in amounts of 0.5%-2% of total hemoglobin. In four presumed homozygotes for Hb KD, up to 10% of the abnormal hemoglobin was present. The alpha chain of Hb KD was found to be elongated by at least 16 residues, possibly as a result of a mutation of the normal alpha chain termination codon UAA TO UCA, coding for serine. A pedigree in which two individuals possess Hb KD as well as the alpha chain variant Hb Rampa and normal Hb A proves the existence of two alpha chain loci in this population. Hb DK resembles the previously described Hb Constant Spring [6, 7] in many aspects, probably also in its alpha thalassemia-like expression.     

Hemoglobin polymorphism in the deer mouse,Peromyscus maniculatus

Horizontal starch gel electrophoresis reveals three hemoglobin phenotypes in natural populations of the deer mouse, Peromyscus maniculatus,from northern Arizona. Phenotypic variation is controlled by a single locus. A sample of deer mice from Michigan was monomorphic for a multiple-banded phenotype. Hemoglobin polymorphism was also observed in Arizona samples of the species Peromyscus boylii.This investigation was supported by Public Health Service Research Grant R01-GM12190.     

Occurrence of fumonisins in asparagus (asparagus officinalis L.) and garlic (allium sativum L.) from Germany

Fusarium proliferatum is able to produce fumonisins and is considered a pathogen of many economically important plants (e.g. corn, rice, asparagus) [1]. The occurrence of fumonisin FB₁ inF. proliferatum infected asparagus spears from Germany was investigated using a liquid chromatography/electrospray ionization-mass spectrometry (LC-ESI-MS) method with isotopically labeled fumonisin FB₁-d₆ as internal standard. Asparagus samples were harvested in July 2000 and screened forFusarium species. AltogetherF. oxysporum, F. proliferatum and F. sambucinum were isolated from the spears. The samples infected with F.proliferatum were subsequently analyzed for fumonisins. FB₁ was detected in 9 of the 10 samples in amounts ranging from 36.4 ng/g to 4513.7 ng/g (based on dry weight). Fumonisins FB₂ and FB₃ were found in six samples in lower concentrations. In asparagus spears of June 2002 we could findF. proliferatum in 6% of the samples, however no fumonisins were detectable. Furthermore the capability of producing FB₁ by the fungus in garlic bulbs was investigated. Therefore garlic was cultured inF. proliferatum contaminated soil and the bulbs were screened for infection with F.proliferatum and for the occurrence of fumonisins by LC-MS. F.proliferatum was detectable in the garlic tissue and all samples contained FB₁ (26.0 ng/g to 94.6 ng/g). This is the first report of the natural occurrence of FB₁ in German asparagus spears and furthermore our findings suggest a potential for natural contamination of garlic bulbs with fumonisins. For detailed results and methods see Ref. [2].     

Prostaglandin E2 mediated effects on the synthesis of fetal and adult hemoglobin in blood erythroid bursts

The effects of prostaglandin E₂ (PGE₂) in association with erythropoietin on the synthesis of fetal and adult hemoglobin in peripheral blood-derived erythroid burst colonies from normal adults and from patients with sickle cell anemia were investigated. The synthesized hemoglobin at the end of 8, 14 or 18 days in culture was separated by DEAE-cellulose chromatography of ³⁵S-methione labelled hemoglobin. Quantitative estimation of the synthesized hemoglobin phenotypes, for the three indicated culture periods, showed preferential synthesis of Hb F in addition to an overall increase in hemoglobin synthesis in PGE₂ treated colonies. Furthermore, the reactivation of fetal hemoglobin production by PGE₂ was more pronounced when the adherent cells were included in the culture dishes. These results indicate that the addition of PGE₂ to culture dishes presumably constitutes an environmental change to promote the functional seen in the blood erythroid bursts in terms of Hb synthesis and switching.     

Hemoglobin attenuates the effects of inspired oxygen on plasma isofurans in humans during upper-limb surgery

Reperfusion injury is characterized by significant oxidative stress. F₂-isoprostanes (F₂-IsoP's) and isofurans (IsoF's), the latter preferentially produced during increased oxygen tension, are recognized markers of in vivo oxidative stress. We aimed to determine whether increasing oxygen tension during reperfusion modified levels of plasma total IsoF's and F₂-IsoP's. Forty-five patients undergoing upper-limb surgery were randomized to receive inspired oxygen concentrations of 30, 50, or 80% during the last 15 min of surgery. Venous blood samples were taken before the change in inspired oxygen, after 10 min (before reperfusion), and after 15 min (5 min after reperfusion). IsoF's and F₂-IsoP's were measured by gas chromatography-mass spectrometry. Venous oxygen tension and hemoglobin concentrations were also measured. Plasma IsoF and F₂-IsoP levels in the 50 and 80% O₂ groups were not significantly different from those of the 30% O₂ group. In secondary analyses, using data combining all groups, levels of IsoF's, but not F₂-IsoP's, associated with higher venous oxygen tension (P = 0.038). Hemoglobin negatively modified the influence of oxygen tension on levels of IsoF's (P = 0.014). This study has shown, for the first time, that plasma IsoF levels associate with higher oxygen tension in a human model of reperfusion, and this effect is significantly attenuated by hemoglobin.     

Metabolism of thromboxane B2 in the cynomolgus monkey

[5,6,8,9,11,12,14,15-³H₈]-Thromboxane B₂ was injected into the saphenous vein of female cynomolgus monkeys, and blood samples were withdrawn from the contralateral saphenous vein. The compound was eliminated from the circulation with a half-life of about 10 min after an initial rapid disappearnace. Some more polar products appeared with time, and also small amounts of material less polar than thromboxane B₂; however, the dominating compound in all blood samples was unconverted thromboxane B₂.About 45% of the given dose of tritium was excreted into urine in 48 hrs. Several metabolites of thromboxane B₂ were found. The major urinary metabolites was identified as dinorthromboxane B₂ (about 32% of urinary radioactivity). Unconverted thromboxane B₂ was also found in considerable amounts (13% of urinary radioactivity).It is concluded that 1) dehydrogenation at C-12 is not a major pathway in the degradation of this compound, in contrast to metabolism at the corresponding C-15 alcohol group of prostaglandins; 2) after having gained access to the circulation, thromboxane B₂ is the main circulating compound; however, assay of thromboxane B₂ in plasma will be complicated or precluded by large artifactual production of the compound by platelets during sample collection.     

Hemoglobin New York in Chinese subjects in Taiwan

Hemoglobin K Kaohsiung has been found, during our population survey in Taiwan, in nine unrelated Chinese subjects with provincial origins from several parts of Mainland China and Taiwan. It also was seen in four relatives of the nine subjects. Present chemical structure studies indicate that it has the same structural anomaly as that previously reported in a variant found in members of a Cantonese Chinese family in New York. That variant, called Hemoglobin New York, has the structural change, β113 Valine→Glutamic acid. Preliminary evaluation suggests that this hemoglobin is one of the most common variants in Chinese population groups although it frequently may be undetected by the usual electrophoretic screening procedures. All of the subjects detected thus far were heterozygotes with nearly equal amounts of Hemoglobin A_o and K Kaohsiung. Hemoglobin K Kaohsiung exhibits slightly reduced heat stability compared with that of Hemoglobin A_o; however, its presence in the heterozygote apparently causes no more than mild anemia.     

Production, Purification, and Characterization of Recombinant Human Hemoglobin Rainier Expressed inSaccharomyces cerevisiae

Hemoglobin Rainier is a naturally occurring hemoglobin variant in which the β145 tyrosine is substituted with cysteine. The α and β^Rainierglobin cDNAs were cloned in a high copy number vector and expressed inSaccharomyces cerevisiaeunder the control of galactose-regulated hybrid promoters. Using this system, we have expressed individual α and β^Rainierglobin chains. Coexpression of both α and β^RainiercDNAs resulted in the production of a functional hemoglobin molecule. Purification of the recombinant protein was accomplished by ion exchange chromatography. The N-termini of the α and β chains were correctly processed, and the molecular mass, as determined by mass spectrometry, indicated amino acid composition identical to that of natural hemoglobin Rainier. The chromatographic properties of the recombinant hemoglobin Rainier were similar to human-derived hemoglobin A₀. The purified recombinant hemoglobin molecule was shown to have an elevated oxygen affinity and a reduced cooperativity as previously reported for natural hemoglobin Rainier. Production of recombinant hemoglobin and especially hemoglobin variants like hemoglobin Rainier has the potential to facilitate use of hemoglobin as a blood substitute as well as in specific applications, such as for use as a therapeutic agent in the treatment of hypotension associated with septic shock.     

Carbon partitioning in Norway spruce: amounts of fructose 2,6-bisphosphate and of intermediates of starch/sucrose synthesis in relation to needle age and degree of needle loss

Summary Intermediates involved in carbon partitioning between starch and sucrose [dihydroxyacetone phosphate + glyceraldehyde 3-phosphate (TP), 3-phosphoglyceric acid, fructose 6-phosphate (F6P), fructose 2,6-bisphosphate (F26BP), in addition to glucose, fructose, sucrose and starch] were analysed in lyophilized needles of Norway spruce (Picea abies L. Karst). Samples were taken from all distinct parts of first and second order branches and the analysed data related to season, needle age, needle position and degree of needle loss (control and class 2 approx. 30%–40% needle loss). Positive and inverse correlations of F26BP, an important regulator of carbon partitioning between starch and sucrose, and F6P or TP existed in all samples. F26BP levels were highest in developing needles and gradually decreased during maturation, which is possibly indicative of changes in the relative sink strength during development (switch from import to export of sucrose). In class 2 needles the amount of F26BP was significantly increased. Together with nearly unaltered levels of sucrose but only slightly decreased amounts of starch the results can be taken as evidence for impaired carbon export in our class 2 samples. The data are discussed with respect to needle development and a possible impact of both air pollutants and mineral deficiency at the location from which the samples were taken.