Utilization of different methodologies for the characterization of Hb Hasharon heterozygotes

Hb Hasharon has an electrophoretic mobility similar to that of Hb S in cellulose acetate and a mobility between Hb S and C at acid pH. In high-performance liquid chromatography, Hb Hasharon shows a distinct chromatographic profile and retention time. The origin of this variant is a mutation in codon 47 (GAC → CAC) of the α2-globin gene, resulting in the replacement of asparagine by histidine during the translation process. Ten blood samples from individuals suspected of being Hb Hasharon carriers were analyzed. In addition to classic laboratory tests and high-performance liquid chromatography, molecular analysis by polymerase chain reaction with restriction fragment length polymorphism designed in the laboratory was performed to confirm this mutation. The study of these cases showed that a combination of classical and molecular methodologies is necessary in the diagnosis of hemoglobinopathies for a correct hemoglobin mutant identification. The accurate identification of hemoglobin variants is essential for genetic counseling and choice of therapy. ©FUNPEC-RP.

Electrophoretic and chromatographic profile for S-like hemoglobin

Hemoglobin variants originate mainly by simple amino acid substitutions, the result of nucleotide sequence changes. Recently, the number of known abnormal hemoglobins has increased due to improvement in analysis methodologies; however, many laboratories are not prepared to correctly identify mutants. Hb S is a very well-characterized hemoglobin variant that varies in prevalence in different regions of Brazil. However, there is a type of Hb that presents electrophoretic migration in alkaline pH similar to Hb S, named S-like Hb, which can be incorrectly diagnosed; therefore, its frequency is underestimated. We obtained reference ranges for Hb S by HPLC, and we examined the electrophoretic and chromatographic profiles of S-like Hb. Hb Hasharon, Hb D-Los Angeles, Hb Korle-Bu, Hb Lepore, Hb D-Iran, Hb G-like, Hb Queens, Hb Montgomery, and Hb Q-India were found. Cases of association between two beta chain mutants were also found. Electrophoresis in alkaline and acid pH was utilized to initially screen these Hb variants, and globin chain electrophoresis at both high and low pH was performed to identify the globin chain mutant. Chromatographic analysis permitted the identification of the hemoglobin variant and also facilitated the quantification of these variants. Therefore, an association of classical laboratory diagnostic methodologies is fundamental for the correct identification of suspect Hb variants. The S and S-like hemoglobin profiles determined in this study will help in the diagnosis of these variants in health care services.

Abnormal hemoglobin phenotypes in carriers of mild anemia in Latin America.

We looked for abnormal hemoglobins in blood samples sent for diagnosis of anemia. Identification of the hemoglobins was made using electrophoretic, chromatographic and molecular procedures. The 2020 blood samples were of patients from various regions of Brazil and from some other Latin American countries. Among the abnormal hemoglobins that we found, 3.5% are known to be rare, while 51% had an electrophoretic profile similar to that of Hb S at alkaline pH. Differentiation was possible only by combining electrophoretic and chromatographic methods. Hb Hasharon, an alpha globin chain mutant, was the most frequently found variant hemoglobin; it accounted for 14.3% of the abnormal DNA samples. The other abnormal hemoglobin phenotypes displayed distinct electrophoretic profiles; most of them migrated faster than Hb A. The frequencies of the different abnormal hemoglobin profiles that we found reflect the miscegenation of the Latin American population and indicate the importance of hemoglobin studies using various methods in combination for accurate diagnosis and appropriate counseling of carriers and their families.

On the temperature stability of extracellular hemoglobin of Glossoscolex paulistus, at different oxidation states: SAXS and DLS studies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alternative method of smearing samples on slides facilitate visualization of hemoglobin H inclusion bodies in alpha thalassemia

Nas talassemias alfa, a HbH pode ser detectada, nos eritrócitos do sangue periférico como inclusões celulares quando coradas com azul crezil brillante. Este teste simples é útil para o diagnóstico de talassemia alfa, no entanto, a identificação dos corpos de inclusão de HbH é um processo laborioso e os resultados são altamente dependentes do observador. No intuito de melhorar a identificação das inclusões, foi testado um método alternativo para espalhar as amostras nas lâminas. Amostras de sangue foram espalhadas nas lâminas usando-se o método clássico e o método alternativo. O método alternativo permitiu uma melhor identificação das inclusões de HbH do que o método clássico. Nossos resultados mostraram que o método alternativo é uma opção útil para a pesquisa dos corpúsculos de inclusão de HbH naquelas amostras onde o método clássico não o permite.

Hemoglobin Kansas found by electrophoretic diagnosis in Brazil

Hemoglobinas variantes com afinidade anormal ao oxigênio têm sido encontradas em várias partes do mundo. Pela sua afinidade ao oxigênio, estas hemoglobinas variantes têm sido classificadas e 15 variantes com baixa afinidade relatadas. Numerosas hemoglobinas mutantes com afinidade anormal têm também sido relatadas, mas somente poucos casos de Hemoglobina Kansas. Os casos são de pacientes procedentes do Japão, ou de famílias com descendentes japoneses. Neste relato descrevemos um paciente com manifestações de cianose que teve o seu diagnóstico confirmado através da eletroforese.

Hemoglobina Köln diagnosticada em programa de triagem neonatal em São José do Rio Preto, SP

Alterações genéticas em que a mutação de aminoácidos nas globinas afeta a estrutura da molécula tornando-a instável são classificadas como hemoglobinas instáveis. Devido à grande diversidade dos pontos de mutações por substituições e deleções de aminoácidos, as formas de instabilização se apresentam muito variadas. A hemoglobina Köln é a variante instável descrita com maior freqüência na literatura e a terceira descoberta no Brasil, as outras são Hb Niterói e Hb Hasharon. Anemia moderada, icterícia e presença de urina escura caracterizam as manifestações clínicas da Hb Köln. em programa de triagem neonatal identificamos uma criança com suspeita de heterozigose para hemoglobina Köln, confirmada por procedimentos eletroforéticos e HPLC. Avaliações por diferentes metodologias laboratoriais e estudo familiar auxiliam no diagnóstico precoce, possibilitando minimizar os sintomas decorrentes da hemoglobina anormal e a realização do aconselhamento genético e educacional destas alterações hereditárias.

Characterization and oxygen binding properties of des-Arg human hemoglobin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Knowledge extraction using visualization of hemoglobin parameters to identify thalassemia

The analysis of large amounts of data is better performed by humans when represented in a graphical format. Therefore, a new research area called the Visual Data Mining is being developed endeavoring to use the number crunching power of computers to prepare data for visualization, allied to the ability of humans to interpret data presented graphically.This work presents the results of applying a visual data mining tool, called FastMapDB to detect the behavioral pattern exhibited by a dataset of clinical information about hemoglobinopathies known as thalassemia. FastMapDB is a visual data mining tool that get tabular data stored in a relational database such as dates, numbers and texts, and by considering them as points in a multidimensional space, maps them to a three-dimensional space. The intuitive three-dimensional representation of objects enables a data analyst to see the behavior of the characteristics from abnormal forms of hemoglobin, highlighting the differences when compared to data from a group without alteration.

Crystal structure of hemoglobin from the maned wolf (Chrysocyon brachyurus) using synchrotron radiation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)