Capillary electrophoresis and mutational images of hemoglobin sendagi [Β42 (CD1) PHE → VAL; HBB: C.127T→G]

We report two cases of hemoglobin Sendagi in a Romanian family residing in Spain: a four-year-old boy and his mother, who had been previously diagnosed with another type of congenital hemolytic anemia and had undergone splenectomy in her country during childhood. The unstable hemoglobin variant, hemoglobin Sendagi, is characterized by decreased oxygen affinity caused by replacement of one of the critical amino acid residues, phenylalanine beta 42 (CD1) of the beta-chain, with valine in the heme pocket, resulting in methemoglobin formation. As a result of migratory movements in Europe, new disease-causing hemoglobin variants are emerging in our country. Here, capillary electrophoresis enabled the identification of the variant and a molecular study was used to establish an accurate diagnosis.

Caveolins in glial cell model systems: from detection to significance

Glial cells prevail in number and in diversity of cellular phenotypes in the nervous system. They have also gained prominence due to their multiple physiological and pathophysiological roles. Our current knowledge of the asymmetry and heterogeneity of the plasma membrane demands an in depth analysis of the diverse array of membrane microdomains postulated to exist in the context of glial cells. This review focuses and analyzes the studies reported to date on the detection of caveolae membrane rafts and the caveolin family members in glial cell model systems, the conditions leading to changes in their level of expression, and their functional and clinical significance. Outstanding in this work emerge the ubiquitous expression of caveolins, including the typically regarded 'muscle-specific' cav3, in diverse glial cell model systems, their participation in reactive astrogliosis, cancer, and their key relevance to calcium signaling. The knowledge obtained to date demands incorporation of the caveolins and caveolae membrane rafts in our current models on the role of glial cells in heath and neurological disease.

Endocytosis mechanism of P2Y2 nucleotide receptor tagged with green fluorescent protein: clathrin and actin cytoskeleton dependence

Extracellular nucleotides exert a large number of physiological effects through activation of P2Y receptors. We expressed rat P2Y2 (rP2Y2) receptor, tagged with green fluorescent protein (GFP) in HEK-293 cells and visualized receptor translocation in live cells by confocal microscopy. Functional receptor expression was confirmed by determining [Ca2+]i responses. Agonist stimulation caused a time-dependent translocation of the receptor from the plasma membrane to the cytoplasm. Rearrangement of the actin cytoskeleton was observed during agonist-mediated rP2Y2-GFP receptor internalization. Colocalization of the internalized receptor with early endosomes, clathrin and lysosomes was detected by confocal microscopy. The inhibition of receptor endocytosis by either high-density medium or chlorpromazine in the presence of UTP indicates that the receptor was internalized by the clathrin-mediated pathway. The caveolin-mediated pathway was not involved. Targeting of the receptor from endosomes to lysosomes seems to involve the proteasome pathway, because proteasomal inhibition increased receptor recycling back to the plasma membrane.

[HFE gene mutations, hepatic iron content, and histological severity in hepatitis C virus-induced chronic hepatitis]

OBJECTIVE

To study whether any relationship exists between the C282Y and H63D mutations of the HFE gene, iron liver content, and the severity of histological damage in patients with hepatitis C virus (HCV)-induced chronic hepatitis.

MATERIAL AND METHODS

In 72 patients diagnosed with HCV-chronic infection, naïve for antiviral therapy, and undergoing liver biopsy, the Knodell index was established, a morphometric evaluation of hepatic hemosiderin deposits was performed by using a semiautomatic method of image analysis, and mutations of the HFE gene were identified through a polymerase chain reaction on leukocyte genomic DNA by using specific restriction enzymes. The control group for the distribution of HFE genetic variants was composed of 181 healthy individuals with the same ethnic and geographical (white Spaniards) origin.

RESULTS

(Cases/controls): 1. Genotype distribution: a) mutation C282Y: no homozygotes, 6/23 heterozygotes, 66/158 without the mutation (not significant, n.s.); b) mutation H63D: 2/5 homozygotes, 26/52 heterozygotes, 44/124 without the mutation (n.s.). compound heterozygotes 2/6. 2. Allele frequencies: a) mutation C282Y: 0.042/0.064 (n.s.); b) mutation H63D: 0.208/0.171 (n.s.). Four C282Y heterozygous patients had stainable liver iron (p=0.015 vs patients without mutations). Sixty-six patients were not carriers of the C282Y mutation; among them, 26.9% of 26 carriers and 15% of 40 non-carriers of the H63D mutation had liver stainable iron (n.s.). Knodell index score, gender, age at diagnosis, mode of transmission, and serum and liver iron values were not related to the HFE genotype.

CONCLUSIONS

our results suggest that the C282Y mutation, but not the H63D mutation, of the HFE gene is frequently associated with stainable iron in the liver in HCV-related chronic hepatitis. The HFE genotype is not related to the histological severity of the disease.

Two new mutations in cis on (G)gamma chain of fetal hemoglobin: Hb F-Madrid [G gamma 50(D1)Ser-->Cys] and [G gamma 75(E19)Ile-->Thr]

We describe a new structural hemoglobin variant of (G)gamma with two amino acid replacements in cis found in the umbilical cord blood of a neonate in Madrid, Spain. The substitutions were identified on exon 2 of the (G)gamma globin gene, at codon 50 (T CT-->T GT) and at codon 75 (A TA-->A CA). We have named it Hb F-Madrid. The father of the propositus was the carrier of the same (G)gamma chain variant and, moreover, molecular study of alpha genes revealed the loss of an alpha gene (-alpha(3.7)/alpha alpha) both in the propositus and his mother.

Characterization of a new hemoglobin variant: Hb Badalona (beta31[B13]Leu-->Val)

Hemoglobin (Hb) Badalona was identified in a 35-year-old Spanish female and two other family members. All affected subjects presented erythrocytosis and increased oxygen affinity (P(50): 21 mmHg). Hemoglobinopathy was not detected with electrophoretic methods. It was, however, separated and quantified by cation exchange and reverse-phase high-performance liquid chromatography. Hb Badalona accounted for 35% of the total Hb. No significant clinical symptoms were found to be related to this hemoglobinopathy. This is the first case of a Leu-->Val replacement at position beta31(B13) reported in the world literature.

Deletion of BCR region 3' in chronic myelogenous leukemia

The t(9;22)(q34;q11) produces the BCR/ABL fusion gene which codifies a 210 kb protein with a strong tyrosine kinase activity and is involved in cellular development and growth. Because this translocation is a reciprocal event, it could give rise to a second fusion gene, ABL-BCR, on the derivative 9q+. We analyzed the influence of the 3' M-BCR deletion on the clinical picture at diagnosis and disease outcome in 57 patients with a clinical diagnosis of CML. Molecular studies were done on DNA from peripheral blood leukocytes or bone marrow with the restrictions enzymes BglII, EcoRI, HindIII, and BamHI, and the BCR 3' probe (transprobe 1) (Oncogene Science Inc.), which encompasses almost all of the 5.8 Kb of the M-BCR gene area. In 18 patients Southern blot analysis showed deletion of the 3' end of BCR gene (32.7%). There were no significant differences between patients with or without deletion, either in the clinical and laboratory data at the disease diagnosis or at the disease outcome. The absence of differences between the patients with and without 3' BCR deletion supports the hypothesis that the hybrid gene ABL-BCR does not have an important role in leukemogenesis in CML cases.

A novel splice acceptor site mutation of the alpha2-globin gene causing alpha-thalassemia

A novel nondeletional alpha-thalassemia mutation that affects RNA processing, changing the alpha2 IVS-II-142 splice acceptor consensus sequence from AG to AA, has been detected in an Argentinian patient with Hb H disease and her daughter.

The thalassemia syndromes: molecular characterization in the Spanish population

This work compiles the results of our research on alpha- and beta-thalassemias, and includes a literature review of the molecular genetics of alpha- and beta-thalassemias in Spain. We studied 1,564 subjects with thalassemia (294 with beta-thalassemia and 1,264 with alpha-thalassemia) by molecular biology techniques. In relation to beta-thalassemia, a total of 15 different mutations were characterized in a study of 308 chromosomes belonging to 294 unrelated subjects. Eleven were homozygotes (22 alleles), three compound heterozygotes (6 alleles), and the remaining 280 were heterozygotes (280 alleles). A total of 86.6% of the alleles identified can be grouped into five different mutations [IVS-I-1 (G-->A), IVS-I-6 (T-->C), IVS-I-110 (G-->A), codon 39 (C-->T), codons 8/9 (+G)]. In 14 subjects (4.5%), all heterozygotes, it was not possible to identify the alteration responsible for the beta-thalassemia. For alpha-thalassemia, 911 subjects showed heterozygous alpha(+)-thalassemia (872 with -3.7 kb; 14 with -4.2 kb; two with the deletion of 3.5 kb of DNA, and 23 with nondeletional alpha-thalassemia). Two hundred and thirty-three subjects had homozygous alpha(+)-thalassemia (223 for -alpha(-3.7)/-alpha(-3.7)); one for -alpha(-4.2)/-alpha(-4.2); six for -alpha(-3.7)/-alpha(-4.2); one for -alpha(-3.5)/-alpha(-3.7); one for alphaalpha(Nco)/alphaalpha(Nco); one for alpha(HPh)/alpha(Hph)). One hundred patients presented with heterozygous alpha(0)-thalassemia (18 of whom were progenitors of patients with Hb H disease). The alpha(0) determinant was found in 20 patients with Hb H disease associated with -alpha(-3.7). From the DNA analysis were identified the - -(MED), - -(SEA), - -(SPAN) deletions and the - -(MA) mutations; in three cases, a break that affects the distal portion of the short arm of chromosome 16; one of these was associated with the ATR-16 (alpha-thal with mental retardation) syndrome. Triplication of the alpha genes (alphaalphaalpha(-3.7)/alphaalpha) was found in 25 subjects, 16 of whom were associated with a heterozygous beta-thalassemia. Only one patient was homozygous for the triplication of alpha genes (alphaalphaalpha(-3.7)/alphaalphaalpha(-3.7)) that was associated with a heterozygous beta-thalassemia. In the Mediterranean region preventive programs for thalassemia, based on the detection of heterozygote carriers and genetic advice, are not sufficient to reduce the incidence of newborns with major thalassemia. Prenatal diagnosis of thalassemias has given a new dimension to the prevention of these, but in order to implement this, a knowledge of the mutations and the incidence of these, is essential. This study, therefore, aims to give a general picture of the molecular genetics of thalassemia and its geographical distribution in our area.

P2Y(2) nucleotide receptor signaling in human monocytic cells: activation, desensitization and coupling to mitogen-activated protein kinases

Activation of P2Y(2) receptors by extracellular nucleotides has been shown to induce phenotypic differentiation of human promonocytic U937 cells that is associated with the inflammatory response. The P2Y(2) receptor agonist, UTP, induced the phosphorylation of the MAP kinases MEK1/2 and ERK1/2 in a sequential manner, since ERK1/2 phosphorylation was abolished by the MEK1/2 inhibitor PD 098059. Other results indicated that P2Y(2) receptors can couple to MAP kinases via phosphatidylinositol 3-kinase (PI3K) and c-src. Accordingly, ERK1/2 phosphorylation induced by UTP was inhibited by the PI3K inhibitors, wortmannin and LY294002, and the c-src inhibitors, radicicol and PP2, but not by inhibitors of protein kinase C (PKC). The phosphorylation of ERK1/2 was independent of the ability of P2Y(2) receptors to increase the concentration of intracellular free calcium, since chelation of intracellular calcium by BAPTA did not diminish the phosphorylation of ERK1/2 induced by UTP. A 5-minute treatment with UTP reduced U937 cell responsiveness to a subsequent UTP challenge. UTP-induced desensitization was characterized by an increase in the EC(50) for receptor activation (from 0.44 to 9.3 microM) and a dramatic ( approximately 75%) decrease in the maximal calcium mobilization induced by a supramaximal dose of UTP. Phorbol ester treatment also caused P2Y(2) receptor desensitization (EC(50) = 12.3 microM UTP and maximal calcium mobilization reduced by approximately 33%). The protein kinase C inhibitor GF 109203X failed to significantly inhibit the UTP-induced desensitization of the P2Y(2) receptor, whereas the protein phosphatase inhibitor okadaic acid blocked receptor resensitization. Recovery of receptor activity after UTP-induced desensitization was evident in cells treated with agonist for 5 or 30 min. However, P2Y(2) receptor activity remained partially desensitized 30 min after pretreatment of cells with UTP for 1 h or longer. This sustained desensitized state correlated with a decrease in P2Y(2) receptor mRNA levels. Desensitization of ERK1/2 phosphorylation was induced by a 5-minute pretreatment with UTP, and cell responsiveness did not return even after a 30-minute incubation of cells in the absence of an agonist. Results suggest that desensitization of the P2Y(2) receptor may involve covalent modifications (i.e., receptor phosphorylation) that functionally uncouple the receptor from the calcium signaling pathway, and that transcriptional regulation may play a role in long-term desensitization. Our results indicate that calcium mobilization and ERK1/2 phosphorylation induced by P2Y(2) receptor activation are independent events in U937 monocytes.

An RGD sequence in the P2Y(2) receptor interacts with alpha(V)beta(3) integrins and is required for G(o)-mediated signal transduction

The P2Y(2) nucleotide receptor (P2Y(2)R) contains the integrin-binding domain arginine-glycine-aspartic acid (RGD) in its first extracellular loop, raising the possibility that this G protein-coupled receptor interacts directly with an integrin. Binding of a peptide corresponding to the first extracellular loop of the P2Y(2)R to K562 erythroleukemia cells was inhibited by antibodies against alpha(V)beta(3)/beta(5) integrins and the integrin-associated thrombospondin receptor, CD47. Immunofluorescence of cells transfected with epitope-tagged P2Y(2)Rs indicated that alpha(V) integrins colocalized 10-fold better with the wild-type P2Y(2)R than with a mutant P2Y(2)R in which the RGD sequence was replaced with RGE. Compared with the wild-type P2Y(2)R, the RGE mutant required 1,000-fold higher agonist concentrations to phosphorylate focal adhesion kinase, activate extracellular signal-regulated kinases, and initiate the PLC-dependent mobilization of intracellular Ca(2+). Furthermore, an anti-alpha(V) integrin antibody partially inhibited these signaling events mediated by the wild-type P2Y(2)R. Pertussis toxin, an inhibitor of G(i/o) proteins, partially inhibited Ca(2+) mobilization mediated by the wild-type P2Y(2)R, but not by the RGE mutant, suggesting that the RGD sequence is required for P2Y(2)R-mediated activation of G(o), but not G(q). Since CD47 has been shown to associate directly with G(i/o) family proteins, these results suggest that interactions between P2Y(2)Rs, integrins, and CD47 may be important for coupling the P2Y(2)R to G(o).

A new polymorphim (G->A) in the psizeta1 globin gene

BACKGROUND AND OBJECTIVES

a-globin cluster polymorphisms are obtained with specific restriction enzymes (Xba I, Eco RI, Sac I, Apa I, Bgl II, etc) that can also have implications for genetic analysis. DESIGN AND AND METHODS: We studied three unrelated patients; one from Argentina, one from Spain and one from Australia but of Polish origin. Genomic DNA was digested with several different restriction enzymes and probes, amplified and sequenced with an ABI Prism 310 sequencer.

RESULTS

In the three patients an abnormal 26 kb band appeared when they were studied with restriction enzyme Bgl II and z probe. A fragment of 944 bp was amplified with primers that cover from -280 to +714 bp of the recognition sequence of Bgl II enzyme (AGATCT) localized 5' from pseudogene z1. After digestion of this PCR product with Bgl II, two fragments of 714 and 280 bp were produced in normal controls, whereas in patient #1 the PCR fragment was undigested and in patients 2 and 3 both undigested and digested fragments were observed. Sequencing of the PCR fragment showed that in all three patients it was the same polymorphism (G->A) at nucleotide 153171 of the 16 p sequence found in the Bgl II recognition site that changed to AAATCT.

INTERPRETATION AND CONCLUSIONS

We describe a new polymorphism in the yz1 first exon Bgl II restriction site (G->A). The polymorphism is associated in cis with haplotype -a3.7. The fragment obtained by PCR enabled us to corroborate the presence of the polymorphism quickly without having to use complicated sequencing techniques.

Association of t(9;11)-MLL AF9 and trisomy 8 in an AML-M5 preceded by pancytopenia

The implication of MLL gene rearrangements in the prognosis of acute myeloblastic leukemia is an issue of considerable current interest. We report a case of a young man who initially presented with a pancytopenia and went on to develop a highly-aggressive acute myeloblastic leukemia. At this time, the karyotypic study revealed trisomy 8, a t(9;11) was demonstrated by fluorescence in situ hybridization (FISH) and the MLL/AF4 rearrangement by reverse transcriptase-polymerase chain reaction (RT-PCR).

Differential agonist-induced desensitization of P2Y2 nucleotide receptors by ATP and UTP

The equal potency and efficacy of the agonists, ATP and UTP, pharmacologically distinguish the P2Y2 receptor from other nucleotide receptors. Investigation of the desensitization of the P2Y2 receptors is complicated by the simultaneous expression of different P2 nucleotide receptor subtypes. The co-expression of multiple P2 receptor subtypes in mammalian cells may have led to contradictory reports on the efficacy of the natural agonists of the P2Y2 receptor to induce desensitization. We decided to investigate the desensitization of human and murine isoforms of the P2Y2 receptor, and to rigorously examine their signaling and desensitization properties. For these purposes, we used 1321N1 astrocytoma cells stably transfected with the human or murine P2Y2 receptor cDNA, as well as human A431 cells that endogenously express the receptor. The mobilization of intracellular calcium by extracellular nucleotides was used as a functional assay for the P2Y2 receptors. While ATP and UTP activated the murine and human P2Y2 receptors with similar potencies (EC50 values were 1.5-5.8 microM), ATP was approximately 10-fold less potent (IC50 = 9.1-21.2 microM) than UTP (IC50 = 0.7-2.9 microM) inducing homologous receptor desensitization in the cell systems examined. Individual cell analyses of the rate and dose dependency of agonist-induced desensitization demonstrated that the murine receptor was slightly more resistant to desensitization than its human counterpart. To our knowledge, this is the first individual cell study that has compared the cellular heterogeneity of the desensitized states of recombinant and endogenously expressed receptors. This comparison demonstrated that the recombinant system conserved the cellular regulatory elements needed to attenuate receptor signaling by desensitization.

Mechanisms of agonist-dependent and -independent desensitization of a recombinant P2Y2 nucleotide receptor

UTP activates P2Y, receptors in both 1321N1 cell transfectants expressing the P2Y2 receptor and human HT-29 epithelial cells expressing endogenous P2Y, receptors with an EC50 of 0.2-1.0 microM. Pretreatment of these cells with UTP diminished the effectiveness of a second dose of UTP (the IC50 for UTP-induced receptor desensitization was 0.3-1.0 microM for both systems). Desensitization and down-regulation of the P2Y2 nucleotide receptor may limit the effectiveness of UTP as a therapeutic agent. The present studies investigated the phenomenon of P2Y2 receptor desensitization in human 1321N1 astrocytoma cells expressing recombinant wild type and C-terminal truncation mutants of the P2Y2 receptor. In these cells, potent P2Y2 receptor desensitization was observed after a 5 min exposure to UTP. Full receptor responsiveness returned 5-10 min after removal of UTP. Thapsigargin, an inhibitor of Ca2+-ATPase in the endoplasmic reticulum, induced an increase in the intracellular free calcium concentration, [Ca2+]i, after addition of desensitizing concentrations of UTP, indicating that P2Y2 receptor desensitization is not due to depletion of calcium from intracellular stores. Single cell measurements of increases in [Ca2+]i induced by UTP in 1321N1 cell transfectants expressing the P2Y2 receptor indicate that time- and UTP concentration-dependent desensitization occurred uniformly across a cell population. Other results suggest that P2Y2 receptor phosphorylation/dephosphorylation regulate receptor desensitization/resensitization. A 5 min preincubation of 1321N1 cell transfectants with the protein kinase C activator, phorbol 12-myristate 13-acetate (PMA), reduced the subsequent response to UTP by about 50%, whereas co-incubation of PMA with UTP caused a greater inhibition in the response. The protein phosphatases-1 and -2A inhibitor, okadaic acid, partially blocked resensitization of the receptor. Furthermore, C-terminal truncation mutants of the P2Y2 receptor that eliminated several potential phosphorylation sites including two for PKC were resistant to UTP-, but not phorbol ester-induced desensitization. Down regulation of protein kinase C isoforms prevented phorbol ester-induced desensitization but had no effect on agonist-induced desensitization of wild type or truncation mutant receptors. These results suggest that phosphorylation of the C-terminus of the P2Y2 receptor by protein kinases other than protein kinase C mediates agonist-induced receptor desensitization. A better understanding of the molecular mechanisms of P2Y2 nucleotide receptor desensitization may help optimize a promising cystic fibrosis pharmacotherapy based on the activation of anion secretion in airway epithelial cells by P2Y, receptor agonists.

Erythropoietin plus granulocyte colony-stimulating factor in the treatment of myelodysplastic syndromes. Identification of a subgroup of responders. The Spanish Erythropathology Group

BACKGROUND AND OBJECTIVE

Anemia leading to transfusion is probably the most important problem in patients with myelodysplastic syndromes (MDS). Human recombinant erythropoietin (rHuEpo) and granulocyte colony-stimulating factor (G-CSF) have been used to treat patients with anemia of MDS, but fewer than 50% respond. The aim of this work was to evaluate the benefit of rHuEpo +/- G-CSF treatment and to isolate the response predictive variables in a group of selected patients with MDS.

DESIGN AND METHODS

A non-randomized multicenter trial was carried out in 32 patients with MDS. The inclusion criteria were age >= 18 years, refractory anemia (RA) or refractory anemia with ringed sideroblasts, Hb <= 100 g/L or receiving transfusions and serum erythropoietin <= 250 U/L. These patients were treated with subcutaneous rHuEpo (300 U/kg) three times a week for 8 weeks. In the case of partial response (PR) or no response (NR) subcutaneosly administered G-CSF (1 microg/kg) three times a week was added to the rHuEpo for 8 more weeks. If the patient achieved complete response (CR) or PR in the second phase, he was included in a follow-up phase of 24 weeks in which the dose of growth factors was tapered down. Several variables, including the score published by the Scandinavian-American group, were used as possible predictive variables.

RESULTS

An erythroid response was observed in 16 patients (50%); in 12 it was a CR and in 4 it was a PR. During the period of rHuEpo administration, 7 CR and 4 PR (34.4%) were documented. Of the 14 patients in whom G-CSF was added to rHuEpo, 7 (50%) responded (3 CR and 4 PR). No major side-effects associated with growth factors were observed. The multivariate analysis showed that of the different variables evaluated only the Scandinavian-American response score was significant with a relative probability of response of 11.8 (95% confident intervals: 2.5-53) when this score was > +1 (77% of cases responded). In contrast, when this score was <= 1 only 15 % of the cases responded.

INTERPRETATION AND CONCLUSIONS

Use of the Scandinavian-American response score is to be recommended in a patient-oriented approach to treating MDS cases with the Epo and G-CSF. Treatment with rHuEpo and G-CSF is safe, its main drawback being its cost. However, a long-term study evaluating the regimen's cost-benefit ratio is warranted.

Identification of the Hb Lepore phenotype by HPLC

BACKGROUND AND OBJECTIVE

Hb Lepore is a structurally abnormal hemoglobin in which the abnormal globin chain is a hybrid or fused globin chain (db). Three different Lepore hemoglobins have been identified, differing from each other in the point at which the db fusion occurs; Hb Lepore Hollandia (d22/b50), Hb Lepore Baltimore (d59/b86) and Hb Lepore Boston (d87/b116). In Spain only Hb Lepore Boston and Hb Lepore Baltimore have been identified. Hb Lepore is easily detected by electrophoretic and chromatographic studies, whereas the type of Hb Lepore is distinguished by chromatography of tryptic peptides of abnormal db chain. In this work, we show an easier chromatography technique for identifying the Hb Lepore phenotype.

DESIGN AND METHODS

Thirteen different unrelated families (23 patients) from different parts of Spain were studied. The existence of Hb Lepore was diagnosed by standard methodology and quantified by ionic exchange HPLC. The globin chains were studied by reversed phase HPLC, which showed us the phenotype of Hb Lepore; this phenotype was corroborated by a gold standard test using molecular biology techniques. The statistical analysis was designed to determine the behavior of the quantitative (hematologic) variables using the independent variable (Hb Lepore Baltimore or Hb Lepore Boston) categorized by Student's t-test for independent groups. The distribution of the variable was established using theoretical models and the variance homogeneity hypothesis was tested. The validity of the hematologic data was estimated by creating a receiver operating characteristic (ROC) curve.

RESULTS

In the study of globin chains by reversed phase HPLC, in 14 patients (8 families) three peaks were eluted; they corresponded to a, b and db globin chains. In these cases when DNA was studied by PCR followed by digestion with the restriction enzyme Pvu II, the phenotype of Hb Lepore was identified as being the Boston variant, whereas in the rest of patients (9 in total), the peak identified with hybrid chain globin (db) was not present and the molecular study showed that these patients were heterozygotes for Hb Lepore Baltimore.

INTERPRETATION AND CONCLUSIONS

The study of globin chains by reversed phase HPLC is sufficient to know the phenotype of Hb Lepore and thus tedious techniques such as chromatography of tryptic digestion product of db abnormal chains are not essential, a particularly important consideration in those laboratories that do not have the possibility of carrying out molecular biology studies. Neverteheless, we should continue to use a gold standard molecular biology test in cases of prenatal diagnosis because this technique is the most exact and reproducible that we have.

Cleavage of the ALL1 gene in acute lymphoid leukemia before treatment disappears in relapse

BACKGROUND AND OBJECTIVE

ALL1 gene rearrangements are frequently found in secondary acute leukemias (ALs). A site-specific cleavage of the ALL1 gene in a consensus sequence for topoisomerase II recognition has been considered to be the initial step leading to ALL1 rearrangement and subsequent therapy-related AL. The aim of the present study was to evaluate this cleavage in our patients, to analyze whether it is a laboratory-produced artefact and to check whether it persists or causes a real ALL1 gene rearrangement at relapse.

DESIGN AND METHODS

We studied ALL1 rearrangement in 74 cases of AL before treatment by Southern blot avoiding room temperature exposure or delay in processing the samples which could produce ALL1 cleavage. DNA was available for two cases with ALL1 cleavage; it was analyzed by three different Southern blots in one and two in the other. One case with ALL1 cleavage was also studied in relapse.

RESULTS

The presence of the cleavage of the ALL1 DNA was found in 3 of 74 (4%) patients. Two of these three patients had the ALL1 cleavage in three and two different analyses. One case was positive for ALL1 cleavage at diagnosis, but negative for both ALL1 cleavage and ALL1 rearrangement at relapse.

INTERPRETATION AND CONCLUSIONS

The fact that a constant pattern was obtained from the same patients in different DNA preparations, supports the notion that ALL1 cleavage is not a laboratory artefact. The absence of the cleavage in a sample from a relapsed patient suggests that the subclone with the ALL1 cleavage, in this case, did not play a clear role in the pathogenesis of disease recurrence.

[The relationship between the persistence of the BCR/ABL gene and relapse in adult patients with acute lymphoblastic leukemia]

BACKGROUND

The Philadelphia chromosome (Ph') is originated by the t(9;22) which determines the rearrangement BCR/ABL. This rearrangement has been associated with an unfavourable prognosis in patients diagnosed with adult acute lymphoblastic leukaemia (ALL).

PATIENTS AND METHODS

The BCR/ABL gene (p210 and p190) was prospectively studied by nested RT-PCR in 17 adult patients diagnosed with ALL BCR/ABL-positive cases were monitored by RT-PCR and cytogenetic techniques over the treatment period (LAL-93 AR protocol).

RESULTS

BCR/ABL mRNA was detected in 8 out the 17 patients studied (47%). The Ph' chromosome was detected in 4 cases. Follow-up was completed in 6 out of the 8 BCR/ABL positive cases. PCR only became negative in one patient. The 5 patients with persistently positive BCR/ABL relapsed, whereas the case which became negative was still in complete remission after 24 months follow-up. In 3 out of the 4 Ph' positive patients, the karyotype was normal after induction therapy.

CONCLUSIONS

This study clearly demonstrates the usefulness of molecular analysis in the diagnosis and follow-up of ALL compared with conventional cytogenetic techniques. The importance of molecular analysis to assess the efficacy of the treatment used has been emphasized and the poor evolution of BCR/ABL-positive patients has been confirmed.

Desensitization of P2Y2 receptor-activated transepithelial anion secretion

Desensitization of P2Y2 receptor-activated anion secretion may limit the usefulness of extracellular nucleotides in secretagogue therapy of epithelial diseases, e.g., cystic fibrosis (CF). To investigate the desensitization process for endogenous P2Y2 receptors, freshly excised or cultured murine gallbladder epithelia (MGEP) were mounted in Ussing chambers to measure short-circuit current (Isc), an index of electrogenic anion secretion. Luminal treatment with nucleotide receptor agonists increased the Isc with a potency profile of ATP = UTP > 2-methylthioATP >> alpha,beta-methylene-ATP. RT-PCR revealed the expression of P2Y2 receptor mRNA in the MGEP cells. The desensitization of anion secretion required a 10-min preincubation with the P2Y2 receptor agonist UTP and increased in a concentration-dependent manner (IC50 approximately 10(-6) M). Approximately 40% of the anion secretory response was unaffected by maximal desensitizing concentrations of UTP. Recovery from UTP-induced desensitization was rapid (<10 min) at preincubation concentrations less than the EC50 (1.9 x 10(-6) M) but required progressively longer time periods at greater concentrations. UTP-induced total inositol phosphate production and intracellular Ca2+ mobilization desensitized with a concentration dependence similar to that of anion secretion. In contrast, maximal anion secretion induced by Ca2+ ionophore ionomycin was unaffected by preincubation with a desensitizing concentration of UTP. It was concluded that 1) desensitization of transepithelial anion secretion stimulated by the P2Y2 receptor agonist UTP is time and concentration dependent; 2) recovery from desensitization is prolonged (>90 min) at UTP concentrations >10(-5) M; and 3) UTP-induced desensitization occurs before the operation of the anion secretory mechanism.

Facile total synthesis and antimicrobial activity of the marine fatty acids (Z)-2-methoxy-5-hexadecenoic acid and (Z)-2-methoxy-6-hexadecenoic acid

The total synthesis of the naturally occurring (Z)-2-methoxy-5-hexadecenoic acid and (Z)-2-methoxy-6-hexadecenoic acid was accomplished using as a key step Mukaiyama's trimethylsilyl cyanide addition to 4- and 5-pentadecenal, respectively. These syntheses further confirm the structures of the natural marine fatty acids and corroborate their cis double-bond stereochemistry. The title compounds were antimicrobial against the Gram-positive bacteria Staphylococcus aureus (MIC 0.35 micromol/mL) and Streptococcus faecalis (MIC 0.35 micromol/mL).

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.

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.

[Usefulness of molecular screening in childhood lymphoblastic leukemias]

PURPOSE

To demonstrate that a molecular screening by reverse transcriptase polymerase chain reaction (RT-PCR) of TEL/AML1, E2A/PBX1 and BCR/ABL genes in pediatric acute lymphoblastic leukaemia is a rapid method that allows one to exceed the percentage of adult patients with the BCR/ABL rearrangement.

PATIENTS AND METHODS

12 Spanish children with acute lymphoblastic leukaemia were studied, 11 of them newly diagnosed and 1 relapsed. The patients were between 18 months and 10 years old. Bone marrow aspiration was collected between april and december 1996, RNA was isolated and cDNA was subjected to PCR amplification for TEL/AML1, E2A/PBX1 and BCR/ABL genes. Normal ABL and E2A genes were studied as amplification controls.

RESULTS

One of these hybrid genes was found in 33.3% of patients studied. TEL/AML1 in two cases (16.6%), E2A/PBX1 in one case (8.3%) and BCR/ABL in another one (8.3%).

CONCLUSIONS

On the basis of these data it would be useful to achieve a molecular screening of TEL/AML1, E2A/PBX1 and BCR/ABL genes in pediatric acute lymphoblastic leukaemia for allowing a molecular classification in a great percentage of patients that exceed the BCR/ABL positivity in adults.

Inhibition of human topoisomerase II by anti-neoplastic benzazolo[3,2-alpha]quinolinium chlorides

Previously we reported [20] that there is no correlation between the cytotoxic activity of four new structural analogs of the antitumor DNA intercalator 3-nitrobenzothiazolo[3,2-a]quinolinium chloride (NBQ-2) and their interaction with DNA. In the present study, we present evidence suggesting that the molecular basis for the anti-proliferative activity of these drugs is the inhibition of topoisomerase II. The NBQ-2 derivatives inhibited the relaxation of supercoiled DNA plasmid pRYG mediated by purified human topoisomerase II. Inhibition of the decatenation of kinetoplast DNA mediated by partially purified topoisomerase II extracted from the human histiocytic lymphoma U937 (a cell line previously shown to be sensitive to the drugs) was also caused by these drugs. The potency of the benzazolo[3,2-a]quinolinium drugs against topoisomerase II in vitro was the following: 7-(1-propenyl)-3-nitrobenzimidazolo[3,2-a]quinolinium chloride (NBQ-59) > 4-chlorobenzothiazolo[3,2-a]quinolinium chloride (NBQ-76) > 7-ethyl-3-nitrobenzimidazolo[3,2-a]quinolinium chloride (NBQ-48) > 7-benzyl-3-nitrobenzimidazolol[3,2-a]quinolinium chloride (NBQ-38). This rank of potency for topoisomerase II inhibition correlated very well with the cytotoxicity elicited by these drugs. Furthermore, significant levels of topoisomerase II/DNA cleavage complex induced by these drugs in vivo were detected when U937 cells were treated with NBQ-59 and NBQ-76 whereas NBQ-38 and NBQ-48 produced negligible amounts of the cleavage complex. Our results strongly suggest that topoisomerase II is the major cellular target of this family of compounds.

Occurrence of BCR-ABL rearrangement in a Philadelphia chromosome-negative patient with 5q and 13q deletions and myeloproliferative syndrome

We report the case of a patient with a myeloproliferative syndrome and traits of myelodysplasia and myelofibrosis whose karyotype showed 5q and 13q deletions, as well as Philadelphia chromosome negativity. A molecular biology study performed by Southern blot, with a probe covering the M-bcr region, led to detection of three bands other than the germinal ones, which hints at the possible existence of two cut points in the M-bcr region of an allele, or participation of both alleles. The patient presented a complex hematological picture, which might be explained on the basis of the cytogenetic and molecular findings.

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

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.

Identification of the novel antimicrobial fatty acid (5Z,9Z)-14-methyl-5,9-pentadecadienoic acid in Eunicea succinea

The phospholipid fatty acid composition of Eunicea succinea was investigated, and the novel (5Z,9Z)-14-methyl-5,9-pentadecadienoic acid was identified. Structural characterization was accomplished by means of mass spectrometry of its pyrrolidide derivative, NMR, FT1R, and total synthesis. Other interesting phospholipid fatty acids in E. succinea were the tetracosapolyenoic acids 6,9,12,15,18,21-tetracosahexaenoic acid (24:6) and 6,9,12,15,18-tetracosapentaenoic acids (24:5). The title compound was particularly active against Gram-positive bacteria such as Staphylococcus aureus (MIC 0.24 mumol/mL) and Streptococcus faecalis (MIC 0.16 mumol/ mL).

[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.

Molecular characterization of a new family with alpha-thalassemia-1 (--MA mutation)

A Spanish family with alpha-thalassemia-1 (alpha-Thal-1), deletion (--MA), is described. In addition to the loss of 22 kb of DNA with a deletion of the alpha 1, alpha 2, psi alpha 2, and psi zeta 1 genes, a triplication of the zeta gene cluster in "cis" is produced. The structure of this triplication is formed by the psi zeta 1 gene, the interzeta region, and, possibly, the insertion of the psi alpha 2 fragment.

[Molecular heterogeneity of beta thalassemia]

PURPOSE

To check out the incidence of beta-thalassaemia in different regions of Spain and to demonstrate its heterogeneity.

PATIENTS AND METHODS

The study was performed on 60 peripheral blood samples from patients diagnosed of beta-thalassaemia by conventional methods, namely, microcytosis, HbA2 over 3.5%, increased HbF. DNA was isolated with phenol-chloroform and amplified by ARMS technique, and in one case its sequence was established according to Sanger's method.

RESULTS

The mutations found in the 67 alleles studied showed similar incidence, although NT1 (IVS 1) mutation was increased and NT110 (IVS 1) mutation was decreased when compared with the findings in other Mediterranean populations.

CONCLUSION

Due to historical reasons, the racial characteristics of Spanish people are the product of different ethnic groups, so hereditary disorders are here usually heterogeneous. This study appears to confirm such fact with respect to beta-thalassaemia.

[The usefulness of the bcr/abl rearrangement in the diagnosis and evolution of chronic myeloid leukemia]

BACKGROUND

The rearrangement of the bcr/abl gene constitutes the molecular substrate of the Philadelphia chromosome (Ph'). The aim of this study was to analyze the usefulness of bcr/abl rearrangement in the diagnosis and evolution of chronic myeloid leukemia (CML).

METHODS

The rearrangement of the bcr/abl gene was studied in 81 cases of which 34 corresponded to patients with CML (29 Ph' positive chromosome, 2 Ph' negative chromosome and 3 without karyotype), 2 patients with Ph' positive acute lymphoblastic leukemia, 15 patients with chronic myeloproliferative syndromes different from CML and 30 controls. Of the patients with CML, 6 were reevaluated when a blastic crisis was developed, 2 after receiving interferon treatment and 1 following allogeneic bone marrow transplantation. The technique used was that of Southern blotting using the restriction enzymes Bgl II and BamHI and the transprobe.

RESULTS

Rearrangement of the bcr/abl gene was observed in all the patients with CML except in one with Ph' negative chromosome. In the remaining cases bcr/abl rearrangement was not observed.

CONCLUSIONS

The Southern blotting technique for the study of the bcr/abl gene rearrangement is a sensitive and specific method in the diagnosis of chronic myeloid leukemia constituting a valid alternative to chromosomic study when this cannot be carried out or is not conclusive. It may also be used for the control of treatment in chronic myeloid leukemia.