carboxymethylcellulose resin at pHs from 7.0 to 10.0, and do not elute with HbA. However, when chemically prepared hemoglobin H (Hbb 4 ) is added to the fresh hemolysates, the free a-chains are readily recovered in the HbA peak. This indicates that the free a-chains are able to combine normally with b-chains to form HbA. Freshly labeled hemolysates were also subjected to Sephadex G-100 chromatography. The free a-chains eluted as a broad peak migrating between myoglobin and hemoglobin, […]
Late-stage erythroid development is largely dedicated to the produc- tion of the oxygen carrier hemoglobin (Hb) A, a tetramer consisting of two pairs of α-globin and β-globin protein subunits with each mono- mer bound to a heme moiety. Hb A synthesis is exquisitely coordinat- ed to minimize the accumulation of freeα- or β-Hb subunits, which are cytotoxic. Excessive α-Hb is particularly damaging, as evidenced by β-thalassemia, a common inherited anemia in which mutations in the β-globin gene impair the production of β-Hb with consequent buildup of the unpaired α-subunit (1–5). Intact monomeric α-Hb generates ROS that damage cellular proteins, lipids, and nucleic acids (6). In addition, α-Hb is structurally unstable, with a tendency to denature upon oxidation, filling the cytoplasm and cell membrane with precipitated α-globin polypeptides, free heme, porphyrins, and iron, which further propagate ROS production (reviewed in ref. 7). Together, these effects reduce the lifespan of circulating erythrocytes and also impair the viability of erythroid precursors in hematopoietic tissues, causing ineffective erythropoiesis.
activity of b Leiden was 1.3-2 times b A . These results indicate preferential destruction of the unstable hemoglobin Leiden. However, in contrast to previous studies of other unstable hemoglobins, there was excess synthesis of a-chains. The total b/a synthesis ratio was 0.47-0.63 in peripheral blood and 0.82 in marrow. A pool of free a-chains was demonstrated by starch gel electrophoresis and DEAE column chromatography. The synthesis of globin chains was balanced in family members […]
synthesis of the abnormal b-chains than b A -chains. The ratio of the specific activities of the a-chains of hemoglobin Gun Hill to the a-chains of hemoglobin A was 20: 1. There was evidence of a free pool of a-chains in the reticulocytes containing hemoglobin Gun Hill. After 10 min of incubation approximately 40% of the total a-chain radioactivity was in the free pool. When protein synthesis was blocked by incubation of reticulocytes with
oxoesters . The importance of thioesters in the cell is well established: biological systems use their relative reactivity in many enzymatic reactions by employing, for example, acetyl coenzyme A, cysteine proteases, or polyketide and fatty acid synthases . Their enhanced reactivity compared to that of oxoesters has been employed successfully in a wide range of synthetic organic transformations, some inspired directly by related biosynthetic pathways. Stereoselective aldol reactions often depend on the distinctive reactivity of thioesters  and their synthetic versatility is further illustrated by many other well-known transformations including α-alkylations,  selective reductions [29, 30], and Pd-catalyzed coupling reactions  among others . Considering these importance, A. W. van Zijl and his coworkers  found a mild and scalable new route to S-ethyl thioacrylate 15 (Scheme 5). The feasibility of the use of this olefin in cross-metathesis reactions with the Hoveyda-Grubbs second generation catalyst is demonstrated. The high functional group tolerance of the reaction allows the preparation of a broad range of versatile functionalized α, β-unsaturated thioesters.
In the presence of PEI-F, the transfection efficiency of TMC-P is significantly improved for both the expression of EGFP and luciferase (Figures 2A, S3, and S4). At high por- tions of PEI-F, the transfection efficiency of TMC-P/PEI-F is even better than that of TMC-P/TMC-F at the optimal N/P ratio, indicating that PEI-F functions better than TMC-F. Moreover, PEI-F can accelerate the gene expression rate of TMC-P in comparison with TMC-F (Figure 2B), which also suggests that PEI-F is superior to TMC-F. Because the addition of PEI-Fs to TMC-P does not lead to a change of its particle size (Figure 1C) and zeta-potential (Figure S9), free polycationic chains may not function by affecting these factors. Interestingly, in later studies, the free polycationic chains added prior to the addition of polyplexes were also found to promote their transfection efficiency (Figure S5) and accumulate intracellularly (Figure 5). The differences between PEI-F and TMC-F are possibly due to their different intracellular functions.
In Italian and Chinese patients with the a-thalassemia syndromes the production of a-chain of normal hemoglobin is decreased relative to that of b-chain in reticulocytes. In this study the relative rates of a- and b-chain synthesis were determined in members of three Negro families with a-thalassemia. Two of the families had members with hemoglobin H disease and a-thalassemia trait, while the mother of several children with a-thalassemia trait in the third family was doubly heterozygous for a-thalassemia and an a-chain mutant. The a/b ratios of globin synthesis in the patients with hemoglobin H disease and a-thalassemia trait indicated less severe biochemical defects in the peripheral blood than those previously determined in Italian and Chinese patients. In the third family, there was a heterogeneity of expression of the gene for a-thalassemia, including patients with normal red cell indices and synthesis ratios. These findings differ from those previously described in patients with a-thalassemia from other racial groups. Hydrops fetalis due to homozygous a-thalassemia may not occur in the Negro because of the relatively mild thalassemic defect.
tests commonly used; however, sensitivity and specificity are low . Genotyping using polymerase chain reaction (PCR) is the standard technique to detect α-thalassemia 1 carriers with high sensitivity [11, 12]. However, compli- cated procedures, time consumption and the requirement for a well-equipped laboratory and expert staff make the genotyping methods unaffordable, especially in resource- limited countries. In (−-(SEA)) α-thalassemia-1 trait, ζ- globin chains have been reported to be present in red blood cells [13–16]. Consequently, immunoassays have been developed for the detection of ζ-globin chains in blood samples and applied for screening of (−-(SEA)) α- thalassemia-1 carriers [13, 14, 16–20]. Previously, we have developed the modified ELISA for the detection of ζ- globin chains using our generated monoclonal antibodies (mAbs) against ζ-globin chains, named mAb PL2 and mAb PL3 . However, the developed ELISA was not appropriate for routine screening of thalassemia.
Out of the 400 cases of microcytosis, only 60 cases were suspected to have β-TT based on the indices. Out of these 60 cases, 40 were confirmed to have β-TT, 2 were diagnosed as sickle cell trait by HPLC. Remaining 18 out of 60 cases were reported to have normal hemoglobin pattern. The remaining 358 cases had been referred to as Microcytic, Hypochromic group. Further testing of 25 females who turned up with their husbands was done and two are positive for thalassaemic trait.
The mechanisms by which the Corfu dele- tion of γ–δ intergenic sequences upregulate γ-globin and HbF expression remain to be determined. One model for this activity is that chromatin remodeling complexes that are developmental stage specific might act by changing the conformation of chroma- tin in the γ–δ region and thus modifying the interactions between the β-LCR and the downstream globin structural genes (Figure 2) (8). Our group has described such a chromatin remodeling complex, the polypyrimidine (PYR) complex, so named because of its PYR-rich DNA-binding site 1 kb upstream of the human δ-globin gene and located within the Corfu dele- tion (Figure 1) (8, 9). PYR complex is adult
Interestingly, Several proteins that were over-expressed in patients were identified as apoptotic proteins. Of these, five proteins were characterized as common in the apoptotic pathway including cytochrome C, apoptosis inducing factor 1 (AIFM1), caspase 6, tumor necrosis fac- tor ligand 6 (TNFL 6) and tumor necrosis factor receptor super family 12A (TNFR 12A or TWEAK). These pro- teins were involved in both mitochondrial dependent apoptosis (intrinsic mechanism) and death receptor mediated apoptosis (extrinsic mechanism). Previous evi- dence suggests that the pathology and disease progres- sion of b -thalassemia relates to the accumulation of reactive oxygen species (ROS), which can generate DNA adducts in the nucleus and induce the DNA damage pathway. In this study, six proteins encoded by four genes were identified and found to be responsible for DNA damage and responsive mechanisms such as the p53 pathway. Interestingly, we found the isoforms sigma, zeta/delta and gamma of the 14-3-3 protein were over- expressed in patients more than 2 fold as compared with normal donors. These 14-3-3 proteins are involved in cellular pathways including apoptosis and phosphatidyl inositol 3 kinase activity by PANTHER pathway analysis. A schematic diagram of the apoptotic pathway including the identified phosphoproteins in HbE/ b -thalassemic stem cells was proposed (Figure 4).
Thalassemia, a major public health problem in India, especially in tribal populations, is an autosomal recessive inherited blood disorder in which blood transfusion is the mainstay of treatment which in turn may lead to iron- induced injury in the heart, liver, pancreas and endocrine system. The Paediatric tribal population receiving multiple blood transfusions for treatment of β-thalassemia had been studied for evaluating the relationship between iron overload with thyroid dysfunction. Information pertaining to demographics, blood transfusion and the nature of chelation therapy etc. was obtained on one hundred patients, attending Bankura Sammilani Medical College, Bankura, and receiving multiple blood transfusions. Blood samples were analyzed for assessment of serum Ferritin, TSH, fT3 and fT4 concentrations by ELISA and serum iron by auto-analyzer and compared with age and sex matched one hundred healthy comparison group. The study group was found to have higher average serum ferritin, iron and TSH levels but lower fT3 and fT4 levels compared to that of the comparison group but and the difference was statistically significant. There were positive correlations between serum TSH and serum ferritin while TSH had no relation with serum iron. Serum ferritin also possessed positive correlation with serum iron. Serum fT3 and fT4 had no relation with serum ferritin and iron. And it was also found that subclinical hypothyroidism was more than overt hypothyroidism among β-thalassemia major patients and female patients affected much in hypothyroidism than the males.
Thalassemia is the genetic disorder occur primarily due to defective formation of globin chain of the hemoglobin moiety of the RBC. It is a specific type of blood disease which results in consequences of excessive destruction of red blood cells which in turn leads to anemia. In this, RBC breakdown occur at an early stage due to abnormal globin chain unable to protect RBC in oxidative stress. Ultimately, resulting in destruction of RBC. In thalassemia the rate of destruction of RBC is so rapid that it exceeds the liver capacity to metabolize the excess billirubin. Thalassemia is a major health problem, and approximately 1 in 14 of the population is carriers for one of the sub types.
This prospective family study is based on nine index cases of sickle cell-beta-thalassemia and seven index cases of hemoglobin-E-beta- thalassemia. They were selected out of 1500 routinely referred cases, sent for investigation for the cause of anemia and suspected to be suffering from hemoglobinopathies before first blood transfusion, from different peripheral Primary Health Centres (PHCs) and hospitals in the state of Orissa during the period between 2001 to April 2006. Details diagnosis and analysis of the referral cases in Orissa have already been reported elsewhere ,. All the above mentioned index cases and their other available family members such as parents, brothers and sisters were also subjected to clinical examination and investigation for the cause of anemia and genetic/marriage counseling after taking informed consent. In all, there were 30 subjects related with sickle cell-β-thalassemia and 22 for hemoglobin E-β-thalassemia. Background information for each family such as name, age, sex, caste, native place, reproductive history, family pedigree, and clinical signs and symptoms were recorded.
Recently, the small protein αhemoglobin–stabilizing protein (AHSP) was identified and found to specifically bind α-globin, stabilize its structure, and limit the toxic effects of excess α-globin, which are manifest in the inherited blood disorder βthalassemia. In this issue of the JCI, Yu, Weiss, and col- leagues show that AHSP is also critical to the formation and stabilization of normal amounts of hemoglobin, even when α-globin is deficient, indicating unique and previously unidentified roles for this molecule (see the related article beginning on page 1856).
manifestations. Her hemoglobin, like that of the deceased sister, contains hemoglobins A, H, and Bart's. In addition, however, two minor components have been detected. These minor components appear to have abnormal a-chains and are also present in the maternal grandmother, the mother, a maternal aunt, and three other siblings but only in about one- tenth the amount. One of the minor components may be the same as Hb-Thai (25). The father has the characteristics of classical a-thalassemia. These results are discussed in relation to current concepts of a-thalassemia as they relate to “silent” and “classical” a- thalassemia and to possible multiple a-chain loci.
Northern and Central Nations than in Southern Euro- pean Nations, due to migration [15,16]. Further, these rising frequencies of hemoglobinopathies in developed countries will likely increase in the next decades. Firstly because the immigration’s waves from poor regions of the world cannot be stopped and secondly because im- migrant people are young and tend to get married in their same ethnic group and to have a high birth-rate, with a founder effect. In addition, immigrants have often consanguineous marriages which increase the frequency of all the Mendelian recessive disorders, and the major- ity of children affected by hemoglobinopathies in developed countries survive into adulthood because can receive optimal medical care. Therefore, nowadays hemoglobin disorders represent a significant health pub- lic health problem also in developing countries where precocious diagnosis of carriers or of affected individuals is crucial to enable the most appropriate actions of pre- vention and care.
convenient markers for globin synthesis due to the nonthalassemic and thalassemic alleles in patients with sickle b-thalassemia. The unbalanced globin synthesis in the peripheral blood of these patients is explained by the decrease in relative synthesis of b S -chain, in comparison with that of a-chain. This instability is not present in sickle cell trait. The b A - chain synthesis was only unstable in the two patients who had the most marked anemia. The major mechanism for achieving balanced globin production in the bone marrow in the presence of one thalassemic gene appears to be increased synthesis […]