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Biomedical subjects

A Villegas

Publications and source records attributed to A Villegas.

At least 55 records · Page 3Linked to original sources
PubMed1998

Red blood cell phenotypes in alpha-thalassemias in the Spanish population.

BACKGROUND AND OBJECTIVE: alpha-thalassemia is very common on all thalassemic geographical regions. The present work aimed at analyzing the relationship between the degree of microcytosis and hematological parameters and the type of alpha-thalassemic mutation. DESIGN AND METHODS: Five hundred and thirty-six subjects with 4 kinds of alpha-thalassemia were examined using established techniques that determined all hematological parameters, and globin synthesis and molecular biological techniques to study the DNA of globin genes by Southern blotting. RESULTS: Adult carriers of alpha (+)-thalassemia (-alpha/alpha alpha) present very few hematological alterations. In a statistical comparison with normal individuals (alpha alpha/alpha alpha), significant differences were found between the hemocytometric data and the MCV and MCH of heterozygous alpha + thalassemia and the heterozygous alpha zero or homozygous alpha + genotype. Hb H disease was detected in 15 patients, presenting a severe degree of anemia, a significant increase in RDW and globin chain synthesis with an alpha/beta ratio of 0.5 +/- 0.1. INTERPRETATION AND CONCLUSIONS: These data provide reference values for geographical areas where alpha + thalassemia is common. These hematocytometric data, together with hemoglobin analysis, could be useful as a future reference data for new patients diagnosed with alpha-thalassemia.

Adolescent↗
PubMed1998

Detection of bcr/abl mRNA in a case of chronic myelogenous leukemia in long-term remission: CML or sensitivity of detection?

Chronic myelogenous leukemia (CML) is a myelo-proliferative disorder which, after a chronic phase which lasts an average of 3 years, evolves into an acute disease which is resistant to chemotherapy. Nevertheless, a few studies have reported cases in which partial or complete hematologic, cytogenetic and/or molecular remission of the disease were observed either spontaneously or after non intensive chemotherapy, with or without medullar aplasia. Some of these patients later relapsed into a blast crisis. We report a case of CML with clinical and hematologic remission for 19 years after two cycles of busulphan not causing medullar aplasia, negative for the BCR/ABL gene by Southern blot but with the gene's mRNA detectable by hot start nested RT-PCR.

Adult↗
PubMed1998

High incidence of the CD8/9 (+G) beta 0-thalassemia mutation in Spain.

BACKGROUND AND OBJECTIVE: In Spain, as in other Mediterranean regions the most common beta-thalassemia mutations are due to point mutations in gene regions that are critical for production of mRNA, such as [IVS-I-nt1 (G-->A), IVS-I-nt6 (T-->C), IVS-I-nt110 (G-->A)] which interrupt normal RNA processing or nonsense mutations [CD39 (C-->T)] which interrupt the translation of mRNA. The frameshift mutation CD8/9 (+G) is a very common allele in Asian Indians but is rare in the Mediterranean regions in which isolated alleles with this mutation have been found in Israel, Greece, Portugal and Turkey. DESIGN AND METHODS: We performed a molecular analysis of 175 chromosomes corresponding to 233 beta-thalassemia patients (221 heterozygous, 10 homozygous and 2 compound heterozygous) who belong to 169 Spanish families. The study of beta-thalassemia was made by PCR-ARMS, the alpha genes by Southern blot, the phenotype of Hb Lepore by enzymatic amplification and the presence of -158 gamma G C-->T mutation by PCR and digestion with the restriction enzyme XmnL. RESULTS: Twenty of these 233 patients showed the beta-thalassemia mutation CD8/9 (+G) (17 were heterozygous, 2 homozygous and in one patient the mutation was associated with a structural variant Hb Lepore Boston). INTERPRETATION AND CONCLUSIONS: These data reveal the heterogeneity of beta-thalassemia in Spain and the relatively high frequency (8.6%) of the frameshift mutation CD8/9 (+G). It is surprising that homozygotes for beta zero-thalassemia due to this mutation with very high Hb F values (around 90%) present a phenotype of intermediate thalassemia.

CD8 Antigens↗
PubMed1997

[High-dose chemotherapy with four drugs and peripheral blood progenitor cell autologous transplantation in disseminated breast cancer].

OBJECTIVE: To evaluate the therapeutic efficacy (in terms of overall survival [OS] and progression-free survival [PFS]) of a high-dose chemotherapy protocol including four drugs and peripheral stem cell rescue (PSCR) plus posttransplant G-CSF (filgrastim) in disseminated breast cancer patients. PATIENTS AND METHODS: Fifty-three metastatic breast cancer patients were treated with a four-drug program of high-dose chemotherapy including cyclophosphamide (6 g/m2), thiotepa (500 mg/m2), carboplatin (800-1,600 mg/m2) and mitoxantrone (20-60 mg/m2) with autologous peripheral blood progenitor cell support followed by filgrastim. Most cases (92%) had previously received conventional induction chemotherapy with anthracycline-containing combinations. RESULTS: After a median follow-up of 27 months (range 12-43 months) from transplant, the median survival of the overall group was 25 months, with an OS projected at 43 months of 31%. Patients in complete remission after induction chemotherapy or status NED (no evidence of disease: surgical resection of metastases) presented the best outcome, with a projected PFS of 50% at 43 months. Patients intensified without complete response had a poor outcome. The most important extramedullary toxicity was mucositis. Four patients (7.5%) died as a consequence of treatment (2 with sepsis-associated ARDS, one with venooclussive disease of the liver, one with congestive cardiac failure). CONCLUSIONS: The outcome of metastatic breast cancer patients in complete remission after induction chemotherapy or NED status seems to be good with our high-dose chemotherapy including four drug and PSCR. On the other hand, patients intensified without complete response presented a bad outcome and do not seem candidates for future trials with this therapeutic approach.

Adult↗
PubMed1997

[Association of alpha and beta thalassemia with alpha gene triplication in one family].

UNLABELLED: We describe the haematological data and molecular results of a native family from Cádiz in that one is produced the a within heterozygous beta 0 thalassaemia (IVS-1, nt 1-G-->A), heterozygous alpha+ thalassaemia (-alpha 3.7) and alpha gene triplication (alpha alpha alpha 3.7). PATIENTS AND METHODS) We are studied 7 members to a family composed by father (I1), mother (I2) and five children (II1, II2, II3, II4, II5). The molecular biology study of the alpha gene was realized by Southern blot method using the restriction enzymes Bam HI, Bgl II and Eco RI and hybridized with alpha probe of the plasmid PRB 1 (fragment of 1.5 Kb digested with the enzyme Pst I). The genes were studied by the technique of the polymerase chain reaction (PCR), modified according to designated method "Amplification Refractory Mutation System" (ARMS). RESULTS: The father (I1) presents an interaction of therozygous beta 0 thalassaemia with heterozygous alpha + thalassaemia (beta 0/beta 1;alpha alpha/-alpha 3). The mother (I2) shows an alpha gene triplication (beta A/beta A: alpha alpha alpha 3.7/alpha alpha). Finally the children are expressed 5 possibilities: II4 he is normal (beta A/beta A; alpha alpha/alpha alpha), II2 he has alpha gene triplication (beta A/beta A; alpha alpha/alpha alpha alpha 3.7), II3 he has heterozygous beta 0 thalassaemia (beta 0/beta A; alpha alpha/alpha alpha), II5 he has interaction between heterozygous beta 0 thalassaemia and heterozygous alpha gene triplication (beta 0/beta A; alpha alpha alpha 3.7/alpha alpha) and II1 presents an interaction between a heterozygous beta 0 thalassaemia and together with the lost of one alpha gene in one chromosome he also presents a alpha gene triplication in other one (beta o/beta A; alpha alpha/alpha alpha). The hematological data of II5 corresponds to a intermediate thalassemia with not transfusion dependent feature an opposite to II1 that presents a heterozygous thalassemic trait features with 4 alpha genes. DISCUSSION: The phenotypical expression of the different interactions of these mutations in this family, points out, the relevant role that the unbalance globins chains plays in the pathogenesis and development of the clinical manifestations of the patients with the thalassaemia syndromes.

Adolescent↗
PubMed1997

[PCR study of bcl-2 rearrangement in autologous transplantation of peripheral stem cells in follicular non-Hodgkin's lymphoma].

OBJECTIVE: To value the usefulness of the bcl-2 rearrangement analysis by PCR in the study of the minimal residual disease in patients with follicular non-Hodgkin's B cell lymphoma (NHL) submitted to peripheral blood stem-cell transplantation (PSCT). PATIENTS AND METHOD: The study was done on 12 patients diagnosed with low grade B-cell NHL, who were entered in a program of myeloablative chemotherapy followed by rescue with progenitor cells obtained from peripheral blood. At the time of peripheral stem-cells (PSC) harvesting, 8 patients did not present medullar infiltration and four of them presented medullar infiltration according to conventional histological criteria. The study was done on DNA from samples taken from bone marrow and cells taken in the apheresis. The DNA samples were studied by PCR to determine the existence of the bcl-2 rearrangement. RESULTS: At the time of apheresis, 8 patients did not present medullar infiltration according to conventional histological criteria but 7 of them presented bcl-2/JH rearrangement. Most patients studied (10 out of 12) showed bcl-2/JH rearrangement (minimal residual disease) in apheresis products. However, in 2 of these 10 patients, such rearrangement was negative in the bone marrow samples obtained 3-6 and 12 months after transplantation. CONCLUSION: In some patients with follicular NHL submitted to PSCT, the bcl-2/JH rearrangement had negativized after transplantation, this implies that the tumoral cells present in apheresis products lost their clonogenic capacity and were not able to subsist in vivo and that the myeloablative polychemotherapy schedules are able to eradicate the t(14; 18) translocation bearing cells or, at least, to decrease their number in bone marrow to levels below those of PCR detection.

Adult↗
PubMed1997

[The association of beta zero-thalassemia and Hb D Punjab in a family of Indian origin. The second case reported in Spain].

The present report described the hematologic and molecular study of the second case of Hb D-Punjab associated with a beta zero-thalassemia found in Spain and the first case in which the mutations have been identified at molecular level. A family from India is studied, which is constituted by mother (I2) and 3 children (II1, II2 and II3). The molecular characterization of the hemoglobinopathy was made by electrophoretic and chromatographic techniques and confirmed by sequencing of the beta-globin gene. The mutation causer of the beta-thalassemia was studied by PCR-ARMS. The mother (I2) and one of her child (II2) are carriers of the gene for beta zero-thalassemia owing to the frameshift CD 8/9 mutation (+ G). Other of them (II1) is heterozygous for Hb D-Punjab without beta-thalassemia association. The third child (II3) knows a double heterozygote state for Hb D-Punjab/beta zero-thalassemia (hemoglobin D-thalassemia). In spite of the patient with hemoglobin D-thalassemia has 94.5% of Hb D, without Hb A, the hematologic picture belongs to thalassemia trait with moderate haemolytic anemia, intense microcytosis and hypochromia and numerous target cells. This hematologic picture discloses the mildness of the Hb D-Punjab, but the reliable responsible for the phenotype is the disbalance in the synthesis of globin chains, because of frameshift CD 8/9 mutation (+ G) beta zero-thalassemia mutation.

Adult↗
PubMed1997

[Identification of 5 variants of the hemoglobin beta chain using DNA analysis (amplification, sequencing and restriction enzymes)].

PURPOSE: To confirm the conventional techniques for studying structural haemoglobinopathies and to show off the simplicity and efficacy of new methods based on the study of DNA. PATIENTS AND METHODS: Peripheral blood samples of 17 patients with 5 haemoglobin variants detected by conventional and shown off by means of sequencing according to Sanger's method, plus PCR-RFLP, were studied. RESULTS: Five structural haemoglobin variants were found, which distributed as follows: 7 cases of Hb Complutense (beta 127 Gln-->Glu), 1 Hb D-Punjab (beta 121 Glu-->Gln), 3 Hb Hofu (beta 126 Val-->Glu), 3 Hb J-Baltimore (beta 16 Gly-->Asp) and 3 Hb San Diego (beta 109 Val-->Met). CONCLUSIONS: These results allow us to stress the simplicity and usefulness of DNA analysis (sequencing , amplification and enzymatic digestion) to identify haemoglobin variants as opposed to laborious analysis of the primary structure by means of HPLC peptide separation.

DNA Mutational Analysis↗
PubMed1997

[Value of analyzing reticulocyte subpopulations in polycythemia].

OBJECTIVE: The evaluation of the RNA content in reticulocytes by means of flow cytometry allows us to differentiate three reticulocyte populations by their degree of maturity: LFR, MFR and HFR. We have studied the value of those reticulocyte subpopulations for the differential diagnosis in polycythemia. PATIENTS AND METHODS: We have studied 25 polycythemia patients, 12 of these were diagnosed of polycythemia vera (PV) and 13 of secondary polycythemia (PS). Reticulocytes and their different reticulocyte populations were automatically analyzed by flow cytometry using the Sysmex R-2000 analyzer (TOA Corp. Japan). We calculated the reticulocyte maturity index (RMI) which is the percentage of the equation (MFR + HFR) x 100/LFR (9). We have also studied hemogram parameters (Hct, Hb, VCM, HCM, RDW, leukocytes and platelets), iron metabolism (serum iron, ferritin, transferrin and transferrin saturation index), and erythropoietin levels. The findings were statistically analyzed using the Pearson correlation test and the comparison tests of averages of independent samples (Student's t). RESULTS: Patients with PV present high RMI and MFR + HFR (medium and high fluorescence reticulocytes) as compared with secondary polycythemia . We did not find any correlation between RMI and other analytical parameters (erythropoietin, ferritin, serum iron, transferrin), except for the transferrin saturation index (TSI), with a correlation factor r: 0.5486 for p < 0.05. CONCLUSION: This higher proportion of younger reticulocytes in PV might be explained because they are a parameter that would reflect the expansion of erythropoietic bone progenitor cells, which would be more increased in PV than in PS. However, another possible explanation would consist in the existence of associated ferropenia in PVs, which lead to an increase in cytoplasmic levels of transferrin receptor mRNA.

Adult↗
PubMed1997

[Molecular analysis of glucose-6-dehydrogenase deficiency in Spain].

PURPOSE: G6PD deficiency is the most frequent enzymopathy-producing genetic polymorphism in humans. Up to now, over 400 putative variants of G6PD have been distinguished on the basis of biochemical characterization of the deficient enzyme. Analysis of the G6PD gene has made possible a precise classification of the G6PD molecular variants by identification of about 80 different point mutations causing much of the phenotypic heterogeneity. In the Spanish population, the analysis of G6PD has led to the identification of 15 different point mutations that underlay the phenotypic heterogeneity of G6PD previously reported by biochemical analysis. The purpose of the study has been to identify the genetic mutation responsible of the G6PD deficiency and to improve the knowledge of its genetic homogeneity. PATIENTS AND METHODS: From 50 Spanish males with G6PD deficiency 34 came from out consultation and 16 from the Spanish Study Group on Red Cell Pathology (GEHBTA-Eritropatología) The methods employed included screening of prevalent mutations by ER-PCR, SSCP-PCR, genetic segmentation and biochemical characterization of the deficient enzyme. RESULTS: In 31 cases the mutations were characteristic of the four most frequent polymorphic variants found in Spain (G6PD A-376G/202A, G6PD Mediterranean 563T G6PD Union 1360T and G6PD Seattle 344C). Since these mutations either create or abolish a specific site recognized by a restriction endonuclease (RE), they can be rapidly detected by RE digestion of a PCR-amplified product (PCR-RE). In patients where none of these mutations were present (17 cases), the G6PD gene was subjected to PCR single-strand conformation polymorphism (PCR-SSCP) analysis combined with direct PCR-sequencing. By using this procedure, 9 new mutations have been identified, five of them have been also found in other geographical areas and were associated with favism (G6PD A-376G/968C, G6PD Santamaria 376G/542T, G6PD Aures 143C and G6PD Chatham 1003A) or chronic haemolytic anaemia (G6PD Tomah 1153C). The other four mutations are unique and not reported so far: Three of them are associated with favism (G6PD Málaga 542T, G6PD Murcia 209G and G6PD Valladolid 406T) and one with chronic haemolytic anaemia (G6PD Madrid 1155G). The remaining eight cases are under study. CONCLUSION: The present study confirms the marked genetic heterogeneity of G6PD deficiency in Spain and demonstrate that the PCR-RE analysis is an easy tool for rapid diagnosis of the molecular defect in subjects with the common forms of G6PD deficiency. Furthermore the fact that G6PD A-376G/202A is the most common variant within Spanish population and the finding of G6PD Aures 43C and G6PD Santamaría 76G/542T, who are polymorphic in Algeria is consistent with a significant gene flow from Africa to Europe through Spain.

Africa, Northern↗
PubMed1997

[High- and low-risk molecular sequences in autoimmune diseases. An analysis of type I diabetes in Latin America].

Type I diabetes is an autoimmune and a polygenic disease, in which MHC-class II genes contribute to 48% of the disease. The aim of the present study, is to provide a guideline to understanding the molecular association of these genes, through the immunogenetic analysis of 3 Latin american mestizo populations. We included 606 individuals, 349 patients with DMDI and 257 healthy controls coming from 3 geographical areas: Mexico City, Mexico; Caracas, Venezuela and Medellin, Colombia. The results clearly indicate that in mestizo groups, the diabetogenic haplotypes are from mediterranean ancestry, while protection is due to Amerindian genes. It was demonstrated that the relevant sequences for IDDM expression are located to DRB1 and DQB1 loci with a minimal contribution of DQA1 residues. The sequences determining peptide recognition and the induction of TH1 cells mediating the cellular autoimmune response are in positions DRB1-57 and 74 (an aspartic acid and a glutamic acid respectively, confer protection), modulated by D-57 in the DQ, 8 chain. These data show that DRB1-DQB1 haplotypes are central for IDDM expression and open new pathways for the disease management.

Adolescent↗
PubMed1996

A family of novel myb-related genes from the resurrection plant Craterostigma plantagineum are specifically expressed in callus and roots in response to ABA or desiccation.

A cDNA and two genomic clones comprising highly similar genes that encode a protein with a Myb-related DNA-binding domain were isolated from the resurrection plant Craterostigma plantagineum. The structure of cpm5 and cpm10 (Craterostigma plantagineum myb) genes consists of three putative exons encoding a protein of 36.6 kDa. The cDNA of cpm7 encodes a closely related protein of 36.8 kDa. The canonical Myb domain present in transcriptional activators of yeast, animals and plants was localized in the amino terminus of deduced Cpm5, Cpm7 and Cpm10 proteins and corresponds to the two Myb repeats found in plants. The Myb domain of Cpm deduced proteins and a short stretch of amino acids adjacent to this region are closely related to a myb gene from Arabidopsis thaliana which is expressed in response to osmotic stress and ABA. The rest of the deduced protein has no similarity to other reported sequences. The myb-related genes in the Craterostigma genome comprise a small gene family of 6-8 members as estimated by hybridization with a bona fide Myb domain probe. Northern blot experiments showed specific expression of cpm10 in undifferentiated callus tissue up-modulated by ABA and expression of cpm7 mRNA in roots up-regulated by dehydration.

Abscisic Acid↗
PubMed1996

Beta-thalassaemia in south-western Spain: high frequency of G-->A (IVS I-1) mutation.

Huelva province is situated in southwestern Spain; its historic and geographic characteristics contribute to the existence of erythrocyte genetic anomalies, such as beta thalassaemia. We have carried out a prenatal study of microcytosis, with a preliminary beta-gene analysis. Our findings show a beta-thalassaemia trait prevalence of 0.81%. In the molecular research there was a high frequency of G-->A (IVS I-1) injury: 55%. By comparing the rates of this mutation neighbouring Cáceres province in western Spain (47%) and Algarve in south Portugal (32%), it demonstrates that this beta-gene defect has a high frequency in the southwest of the Iberian Peninsula.

Child↗