Desnaturação de oxihemoglobinas humanas A, A2 e S pelo metodo de tampão isopropanol

Human oxyhaemoglobin A and A2 from normal individuals and oxyhaemoglobin S from patients with sickle cell anaemia and sickle cell trait were studied using Isopropanol/buffer method at 37°C and 40°C. Hb S was less stable than Hb A, whereas Hb A2 was considerably more stable than either. Denaturation of Hb S was dependent on temperature and its concentration. Between the patients with sickle cell trait it was not possible to verify the influence of the concentration probably due to the small range used (from 38% to 44%).

Caracterização molecular e laboratorial da talassemia beta e da interação hemoglobina s/talassemia beta

Beta thalassemia arises as a consequence of the reduction (β+, β++, βsilent) or absence (β0) of beta globin chain synthesis and results from a number of mechanisms that lead to genetic defects. The inheritance of beta thalassemia is characterized by the existence of heterozygous individuals, compound heterozygotes, homozygotes and those with coinheritance of beta thalassemia allele and other thalassemias and/or hemoglobin variants. The aim of this study was to perform molecular and laboratory characterization of beta thalassemia in heterozygous and homozygous individuals and in those with coinheritance of S beta thalassemia. A total of 48 individuals were included (35 heterozygotes, 4 homozygotes and 9 S beta thalessemia carriers) referred to the Integrated Laboratory of Clinical Analyses of the Federal University of Rio Grande do Norte (UFRN) and the Hematology Ambulatory Facility of the Dalton Barbosa Cunha Hemocenter (Hemonorte Natal, Brazil). Peripheral blood samples form each patient underwent the following laboratory examinations: erythrogram, hemoglobin electrophoresis at alkaline pH, measurements of Hb A2, Fetal Hb and serum ferritin. DNA was extracted using the illustra blood genomicPrep Mini Spin Kit and molecular characterization was performed by the PCR/RFLP technique, which involves digestion with specific restriction enzymes for IVS-1 nt 1 (G®A), IVS-1 nt 6 (T®C) and codon 39 (CAG®TAG) mutations. Of the 35 heterozygotes, 37.1% showed IVS-1 nt 6 mutation, 42.9% IVS-1 nt 1 and 20% were carriers of other mutations not identified by the technique used. The four homozygous patients presented with the IVS-1 nt 6 mutation, while 66.7% of the individuals with S beta thalassemia had the IVS-1 nt 1 mutation. Codon 39 was not detected in any of the patients investigated. Of the thallasemic alleles found, 40.4% were IVS- 1 nt 1, 40.4% IVS-1 nt 6 and 19.2% were not identified. Laboratory data showed that the heterozygotes exhibited microcytosis and hypochromia, evidenced by MCV ranging from 57 to 75fL and MCH from 15.9 to 23.6 pg. Hemoglobin A2 varied between 3.7 and 7.2%. The homogygotes also showed reduced MCV and MCH and elevated HbA2.. Comparison of laboratory data between heterozygous individuals with IVS-1 nt 1 and IVS-1 nt 6 mutations showed that heterozygotes for the IVS1-1 mutation had significantly lower mean MCV and MCH (p = 0.023 and 0.007, respectively) and significantly higher hemoglobin A2 (p < 0.001) when compared to heterozygotes for the IVS-1 nt 6 mutation. PCR/RFLP was useful in identifying the presence or absence of IVS-1 nt 6, IVS-1 nt 1 and codon 39 mutations in most of the patients investigated here. This is the first study conducted in the state of Rio Grande do Norte, Brazil aimed at identifying beta thalassemia mutations and represents an important contribution to the knowledge regarding the molecular profile of beta thalassemia in our country

Determinação de haplótipos do gene βs em portadores de anemia falcifome

Haplotypes linked to the βS gene represent patterns of DNA polymorphisms along chromosome 11 of individuals bearing the βS gene. Analysis of haplotypes, in addition to serving as an important source for anthropological studies about the ethnic origin of a population, contributes to a better understanding of the variations in clinical severity of sickle cell anemia. The aim of the present study was to determine βS gene haplotypes in a group of patients with sickle cell anemia treated at the Dalton Barbosa Cunha Hematology Center (Hemonorte) in Natal, Brazil and the Oncology and Hematology Center in Mossoró, Brazil. Blood samples were obtained from 53 non-related patients (27 males and 26 females), aged between 3 months and 61 years (mean age: 16.9 ± 12.1 years). Laboratory analyses consisted of the following: erythrogram, reticulocyte count, hemoglobin electrophoresis at alkaline pH, measurement of hemoglobin A2 and Fetal hemoglobin, solubility test and molecular analysis to determine βS gene haplotypes. DNA samples were extracted by illustra blood genomicPrep Mini Spin kit and βS gene haplotypes were determined by PCR-RFLP, using Xmn I, Hind III, Hinc II and Hinf I restriction enzymes for analysis of six polymorphic restriction sites in the beta cluster. Of 106 βS chromosomes studied, 75.5% were Central African Republic (CAR) haplotype, 11.3% Benin (BEN) and 6.6% Cameroon (CAM). The atypical haplotypes had a frequency of 6.6%. More than half the patients (58.5%) were identified as CAR/CAR genotype carriers, 16.9% heterozygous CAR/BEN, 13.2% CAR/CAM and 1.9% BEN/BEN. Patients with atypical haplotype in one or two chromosomes accounted for 9.5% (CAR/Atp, BEN/Atp and Atp/Atp). The genotype groups showed no statistically significant difference (p < 0.05) in their laboratory parameters. This is the first study related to βS haplotypes conducted in state of Rio Grande do Norte and the higher frequency of Cameroon halotype found, compared to other Brazilian states, suggests the existence of a peculiarity of African origin

HPLC determination of hemoglobins to establish reference values with the aid of statistics and informatics

The purpose of the present study was to establish reference values for hemoglobins (Hb) using HPLC, in samples containing normal Hb (AA), sickle cell trait without alpha-thalassemia (AS), sickle cell trait with alpha-thalassemia (ASH), sickle cell anemia (SS), and Hb SC disease (SC). The blood samples were analyzed by electrophoresis, HPLC and molecular procedures. The Hb A2 mean was 4.30 ± 0.44% in AS, 4.18 ± 0.42% in ASH, 3.90 ± 1.14% in SS, and 4.39 ± 0.35% in SC. They were similar, but above the normal range. Between the AS and ASH groups, only the amount of Hb S was higher in the AS group. The Hb S mean in the AS group was 38.54 ± 3.01% and in the ASH it was 36.54 ± 3.76%. In the qualitative analysis, using FastMap, distinct groups were seen: AA and SS located at opposite extremes, AS and ASH with overlapping values and intermediate distribution, SC between heterozygotes and the SS group. Hb S was confirmed by allele-specific polymerase chain reaction. The Hb values established will be available for use as a reference for the Brazilian population, drawing attention to the increased levels of Hb A2, which should be considered with caution to prevent incorrect diagnoses. ©FUNPEC-RP.

Avaliação da expressão da talassemia Beta no Brasil pela coherança com defeitos de hemocromatose

Pós-graduação em Genética - IBILCE

Polimorfismo XmnI e haplótipos do gene beta globina e suas relações com os níveis de hemoglobina Fetal em beta talassemia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de Hb A2 e Hb F em doadores de sangue de região malarígena da Amazônia Oriental brasileira por HPLC

In malaria endemic regions of Africa, resistance to infection by Plasmodium has been observed in under 6-month-old children, when there are higher fetal hemoglobin (Hb F) levels. Research performed in the São José do Rio Preto region, central-east Brazil, reported increased levels of Hb F in blood donors. The purpose of this work was to evaluate the A2 hemoglobin (Hb A2) and Hb F concentrations in blood donors deriving from the Brazilian malaria endemic region. Forty-five blood donor samples from Macapá, from patients with varying genders, ages and ethnic origins, were collected by venous puncture after informed consent was obtained. The samples were analyzed by High Performance Liquid Chromatography (HPLC) - System Variant (Bio-Rad). The HPLC demonstrated sensitivity and rapidity in the identification and measurement of the hemoglobins and gave precise results. Moreover, it provided measurement of hemoglobin variants, even when they were present in small amounts, providing a diagnosis of hemoglobinopathies. Hb F levels above the normal were observed in 33.3% of the analyzed samples. The presence of increased Hb F can suggest resistance to infection by Plasmodium falciparum, as there have been reports that infected red blood cells interfere in the development of the parasite.

A free weekly iron-folic acid supplementation and regular deworming program is associated with improved hemoglobin and iron status indicators in Vietnamese women

Background Anemia due to iron deficiency is recognized as one of the major nutritional deficiencies in women and children in developing countries. Daily iron supplementation for pregnant women is recommended in many countries although there are few reports of these programs working efficiently or effectively. Weekly iron-folic acid supplementation (WIFS) and regular deworming treatment is recommended for non-pregnant women living in areas with high rates of anemia. Following a baseline survey to assess the prevalence of anemia, iron deficiency and soil transmitted helminth infections, we implemented a program to make WIFS and regular deworming treatment freely and universally available for all women of reproductive age in two districts of a province in northern Vietnam over a 12 month period. The impact of the program at the population level was assessed in terms of: i) change in mean hemoglobin and iron status indicators, and ii) change in the prevalence of anemia, iron deficiency and hookworm infections. Method Distribution of WIFS and deworming were integrated with routine health services and made available to 52,000 women. Demographic data and blood and stool samples were collected in baseline, and three and 12-month post-implementation surveys using a population-based, stratified multi-stage cluster sampling design. Results The mean Hb increased by 9.6 g/L (95% CI, 5.7, 13.5, p < 0.001) during the study period. Anemia (Hb<120 g/L) was present in 131/349 (37.5%, 95% CI 31.3, 44.8) subjects at baseline, and in 70/363 (19.3%, 95% CI 14.0, 24.6) after twelve months. Iron deficiency reduced from 75/329 (22.8%, 95% CI 16.9, 28.6) to 33/353 (9.3%, 95% CI 5.7, 13.0) by the 12-mnth survey, and hookworm infection from 279/366 (76.2%,, 95% CI 68.6, 83.8) to 66/287 (23.0%, 95% CI 17.5, 28.5) over the same period. Conclusion A free, universal WIFS program with regular deworming was associated with reduced prevalence and severity of anemia, iron deficiency and ho

High-resolution refinement of orthorhombic bovine pancreatic phospholipase A2

The X-ray structure of recombinant bovine pancreatic phospholipase A(2) (PLA2), which specifically catalyzes the cleavage of the sn-2 acylester bond of phospholipids, has been refined at 1.5 Angstrom resolution. The crystal belongs to the space group P2(1)2(1)2(1) with unit-cell parameters a = 47.12, b = 64.59 and c = 38.14 Angstrom similar to the native enzyme reported previously by Dijkstra et nl. [J. Mel. Biol. (1981), 147, 97-123]. The refinement converged to an R value of 18.4% (R-free = 22.8%) for 16 374 reflections between 10.0 and 1.5 Angstrom resolution. The surface-loop residues (60-70) art: ordered in the present orthorhombic recombinant enzyme, but disordered in the trigonal recombinant enzyme. The active-site residues, His48, Asp99, and the catalytic water superimpose well with the trigonal form. Besides the catalytic water which is hydrogen bonded to His48, it is often seen that there is a second water attached to the same N atom of His48 and simultaneously hydrogen bonded to the O atom of Asp49. It is thought that the second water facilitates the tautomerism of His48 for enzyme catalysis, The catalytic water is also hydrogen bonded to the equatorial water coordinated to the calcium ion, In addition to the equatorial water, there is also an axial calcium water and the additional structural water. These five common water molecules are hydrogen bonded to the additional 16 water molecules in the present orthorhombic structure which may further enhance the structural integrity of the active site. Besides the protein and one calcium ion, a total of 134 water molecules were located in the present high-resolution refinement.