[Iron deficiency and pica]. / Déficit de hierro y pica.

PURPOSE: To study the relationship between pica and iron-lack anaemia in a series of iron-deficiency patients in order to establish the pathogenesis of such relationship. PATIENTS AND METHODS: Four-hundred and thirty-three patients were analysed. Pica was studied by introducing certain diet queries into the clinical history. All patients received oral iron and were periodically controlled with the usual clinico-haematological procedures. RESULTS: Pica was present in 23 patients (5.3%). Eight nourishing (namely, coffee grains, almonds, chocolate, ice, lettuce, carrots, sunflower seeds and bread) and 2 non-nourishing (clay and paper) substances were involved. A second episode of pica appeared in 9 cases upon relapsing of iron deficiency. Both anaemia and pica were cured by etiologic and substitutive therapy in all instances. No clear correlation was found with either socio-economic status or pathogenetic causes of iron deficiency and pica, and no haematological differences were seen between patients with pica and those without this alteration. CONCLUSIONS: (1) The pathogenesis of pica is unclear, although it appears unrelated to the degree of iron deficiency. (2) According to the findings in this series, pica seems a consequence of iron deficiency rather than its cause. (3) Adequate therapy can cure both conditions, although pica may reappear upon relapse of iron deficiency.

[Association of alpha and beta thalassemia with alpha gene triplication in one family]. / Asociación de talasemia alpha y beta con triplicación de genes alpha en una misma familia.

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.

Analysis of the complementary determining region III of the immunoglobulin heavy chain locus in acute lymphoblastic leukemia in Chilean children.

We have analyzed the sequence of 40 VDJ rearrangements of the immunoglobulin heavy chain gene locus on 32 unselected children from Chile with precursor B cell ALL at diagnosis. Rearrangements were derived by PCR with VH gene family-specific primers and sequenced directly. The number of VDJ rearrangements, and the pattern of VH, DH and JH gene usage was identical to the one reported by groups from developed countries. CDR3 regions represented an unbiased repertoire; VH to JH joinings were in frame in 36% of cases. Absent N nucleotides in the DJ border, suggestive of fetal origin of ALL, were seen in 9/40 rearrangements but they did not correlate with younger age. More than one rearrangement was sequenced in six patients, representing independent events with no signs of clonal evolution. One patient was analyzed at first bone marrow relapse showing persistence of one rearrangement and evolution of a second one which conserved the DJ border. The subset of B cell precursors which suffer malignant transformation to ALL appear to be common in different parts of the world.

t(1;5)(q23;q33) in a patient with high-risk B-lineage acute lymphoblastic leukemia.

The t(1;5)(q23;q33) is a rare genetic anomaly that was reported previously in two infants with a myeloproliferative disorder and eosinophilia and in one adult patient with acute nonlymphocytic leukemia (ANLL). A 13-year-old boy with high-risk early pre-B acute lymphoblastic leukemia (ALL) who presented to our institution carried the t(1;5)(q23;q33). He had an initial blast count of 230 X 10(9)/L and responded poorly to prednisone. Complete remission (CR) was achieved, and he had a bone marrow (BM) relapse 3 months after despite intensive consolidation therapy. He underwent allogeneic BM transplantation (BMT) from a human leukocyte antigen (HLA)-identical siblings in early relapse with total body irradiation (TBI) and cyclophosphamide conditioning. He had a short second CR with a central nervous system (CNS) relapse on day + 106 after BMT. Two of the previously reported patients also did not respond to chemotherapy. The t(1;5)(q23;q33) appears to be a rare lineage nonspecific anomaly related to hematologic malignancies that are resistant to current therapy.

Rapid intraclonal switch of lineage dominance in congenital leukaemia with a MLL gene rearrangement.

We describe a case of neonatal mixed lineage leukaemia which presented with a dominant B progenitor lymphoblast population plus a minor monocytic component. Treatment of the patient with corticosteroid and Ara-C resulted in loss of lymphoblasts and a rapid (within 7 days) increase and dominance of the monocytic component. The common clonal origin of the two cell types was evident from the identical rearrangement in the MLL gene and a shared rearrangement of one IGH allele. In common with other neonatal or infant ALL with MLL gene rearrangements, this leukaemia may have originated in a common B-monocytic lineage stem cell during foetal haemopoiesis. The observations further suggest that the therapeutic impact of the MLL gene rearrangement is to some extent dependent on the cellular context in which it is expressed.

[Chronic myeloid leukemia: cytogenetic and molecular study and its relationship with the disease course]. / Leucemia mieloide crónica: estudio citogenético y molecular y su relación con la evolución de la enfermedad.

The aim of this study was to perform a cytogenetic and molecular study in patients with chronic myelogenous leukemia and to seek a possible relation between bcr gene break points and the clinical evolution of the disease. The cytogenetic study allowed to establish the presence of Ph chromosome and the molecular study localized the break point in bcr region of chromosome 22 using the Southern technique, hybridizing with bcr fragment derived probes bcr1 and bcr2. Forty eight patients were studied, 27 male (aged 46.5 years) and 21 female (aged 56). Forty seven patients were Ph +. A rearrangement in 3' bcr region was found in 25 patients and in 5' region in 23. During the follow up period 20 patients developed a blast crisis or accelerated phase. In 11 of these the rearrangement was in region'3 and their chronic phase lasted a mean of 33.1 months; in 9 the rearrangement was in region 5' and their chronic phase lasted 44.1 months. There were no differences in event-free survival between those with rearrangement in region 3' or 5', however these was a tendency towards a longer chronic phase duration in those with 5' breaks. The lack of correlation between the location of break points and the evolution of the disease may be due to a selection of patients with a better evolution and the exclusion of those with a rapid progression to blast crisis or accelerated phase.

Molecular epidemiology of Burkitt's lymphoma from South America: differences in breakpoint location and Epstein-Barr virus association from tumors in other world regions.

We have previously shown that the endemic (African) and sporadic (North American) forms of Burkitt's lymphoma (BL) differ at a molecular level. We have now extended our studies to the molecular epidemiology of BL in South America, specifically to two climatic regions: temperate (Argentina and Chile) and tropical (Brazil). We have examined the patterns of chromosomal breakpoint locations in 39 tumors with respect to geography and Epstein-Barr virus (EBV) association. The result of these analyses provide further support for the existence of pathogenetically distinct subtypes of BL in different world regions. The majority of breakpoints on chromosome 8 in South American BL (41%) occurred in the immediate flanking region of c-myc, ie, further 5' of the "typical" sporadic breakpoints, in the first exon/intron region, and further 3' of the "typical" endemic breakpoints, which are usually distant from c-myc. However, the distribution of breakpoints on chromosome 14 in tumors from the temperate and tropical regions of South America is similar to that observed in sporadic and endemic tumors. Interestingly, only one tumor with an unrearranged c-myc gene joined to the S mu region of chromosome 14 was observed. This combination was also rarely observed in our earlier series and presumably is either less readily generated by the mechanism that mediates 8;14 translocation or requires other, infrequent genetic changes to provide the necessary selective advantage for lymphomagenesis. The frequency of EBV association in South American BL (51%) is also intermediate with respect to tumors from the United States (30%) and Africa (100%). No correlation with the breakpoint location on chromosome 8 was discernable. Surprisingly, only 54% of tumors with breakpoint outside c-myc were EBV positive. This is in contrast to endemic tumors and suggests that any pathogenetic contribution of EBV is not dependent on breakpoint location, but is more likely to complement additional pathogenetic elements that differ in different world regions.

[Intermediate thalassemia. Study of 5 cases in their clinical, ferrokinetic and erythrokinetic aspects]. / Talasemia intermedia. Estudio de cinco casos en sus aspectos clínicos, ferrocinéticos y eritrocinéticos.

Five cases of thalassaemia intermedia are reported, they being considered from clinical and biologic standpoints. All patients had long-lasting anaemia, variable enlargement of spleen and low transfusion requirements. The ferro-erythrokinetic pattern was that of chronic haemolysis with effective erythropoiesis, and some comments are included on the different patterns found in each genetic variety. None of the patients is subjected to a defined transfusion protocol.

Modulation of the feedback regulation of thymidine kinase activity by pH in 647V cells.

We have studied the effect of pH on the interactions between thymidine kinase, thymidine triphosphate, and 5'-amino-2',5'-dideoxythymidine (5'-AdThd) in purified preparations of the enzyme and in intact 647V cells, a human bladder cancer cell line. Thymidine kinase is competitively inhibited by 5'-AdThd. dTTP feedback inhibits in a noncompetitive fashion. However, 5'-AdThd partially reverses the inhibition produced by dTTP resulting in enhanced enzyme activity. We have found that dTTP (pKa = 7.5) is a much more potent inhibitor of purified preparations of thymidine kinase activity at low pH conditions. For example, 2.5 microM dTTP inhibited thymidine kinase activity by 50, 85, and 95% at pH values of 8.0, 7.5, and 6.5, respectively. The interaction of 5'-AdThd (pKa = 8.5) at either the active (competitive) or the regulatory (deinhibition) site is not altered significantly over a pH range of 6.5 to 9.5. To extend these findings to intact cells, we studied the perturbation of the uptake of thymidine by 5'-AdThd in 647V cells incubated in media buffered at various pH values. In cells exposed to media buffered at pH 8.5 or 7.5, 5'-AdThd maximally stimulated thymidine uptake about 250 and 300% at 10 and 30 microM, respectively. However, at pH 6.5, 300 microM 5'AdThd was required to produce maximal stimulation of about 500%. These observations are consistent with the greater sensitivity of thymidine kinase (in situ) to feedback inhibition by dTTP at the lower pH conditions. Intracellular dTTP pool sizes were not affected by variations in pH during the short time course of our experiments. However, after 1 h, the intracellular concentration of 5'-AdThd was twice that of the extracellular medium in conditions at pH 7.5 and 8.5 but was equimolar across the membrane at pH 6.5. This does not account for the differences in the perturbation of thymidine uptake by 5'-AdThd at various pH values. In general, our results indicate that regulation of thymidine kinase by dTTP is pH dependent, while its modulation by 5'-AdThd is not, and that regulation of thymidine kinase in situ is sensitive to alterations in pH.

Regulation of the activation of fluorodeoxyuridine by substrate competition and feedback inhibition in 647V cells.

Fluorodeoxyuridine (FdUrd) is a cytotoxic analogue of thymidine which requires activation by thymidine kinase to FdUMP. FdUMP inhibits thymidylate synthetase and, thus, the synthesis of dTTP. 5'-Aminothymidine (5'-AdThd) can antagonize the feedback inhibition exerted by dTTP on thymidine kinase activity and thereby stimulate FdUrd phosphorylation. This provided a novel approach to assess the degree to which end product inhibition regulates the phosphorylation of FdUrd. We used 5'-AdThd to investigate the effects of dThd and IdUrd on the regulation of FdUrd uptake in intact 647V cells, a human bladder cancer cell line. Contributions from catabolic processes were found not to be important in our system. We detected no nucleoside phosphorylase activity in the 647V cells or any effect of 5'-AdThd on the breakdown of 5-fluorodeoxyuridine monophosphate to FdUrd by crude preparations from these cells. Thus, phosphorylation by thymidine kinase determined FdUrd uptake (phosphorylation). In the absence of added nucleosides the rate of FdUrd uptake increased in a time dependent fashion. Diminished feedback inhibition of thymidine kinase appeared to be an important factor, as evidenced by a decrease in intracellular dTTP pools and a time dependent loss in the ability of 5'-AdThd to stimulate FdUrd uptake. Thymidine and iododeoxyuridine inhibited FdUrd phosphorylation (uptake) by two mechanisms: competition for the active site of thymidine kinase and increased feedback inhibition. Increased feedback inhibition was indicated by stimulation of FdUrd uptake by 5'-AdThd. The effects of IdUrd on FdUrd uptake were also time dependent, presumably reflecting accumulation of iododeoxyuridine triphosphate and dTTP pools. FdUrd cytotoxicity was modulated by dThd, IdUrd, and 5'-AdThd in parallel to their perturbation of FdUrd uptake. Individually they reduced the growth inhibitory properties of FdUrd. These results show that the regulation of FdUrd uptake is critically dependent on the presence of dThd and IdUrd and emphasize the potential importance of circulating levels of these nucleosides in mediating FdUrd activation and cytotoxicity.

Biochemical assessment of the effects of acivicin and dipyridamole given as a continuous 72-hour intravenous infusion.

Since this Phase I trial was based on a strategy of biochemical modulation, namely, the inhibition of nucleoside uptake by dipyridamole, a biochemical assessment of the actions of acivicin and dipyridamole was undertaken in order to aid our interpretation of the clinical findings. The primary biochemical objectives of this trial were: (a) to determine whether plasma levels of dipyridamole sufficient to inhibit nucleoside uptake could be achieved with a 72-h continuous i.v. infusion; (b) to monitor the effects of acivicin on two key enzymatic targets, CTP synthetase and GMP synthetase; and (c) to evaluate changes in cellular ribonucleoside triphosphate pools during therapy. Since peripheral blood mononuclear cells have relevant biochemical targets and can be serially obtained during the course of therapy, the biochemical effects of acivicin and dipyridamole were determined in these cells. At the maximally tolerated dose of dipyridamole (23.1 mg/kg/72 h), the steady-state concentrations of total and free dipyridamole averaged 11.9 microM and 27.8 nM, respectively. These levels were sufficient to inhibit cytidine (1 microM) uptake by greater than 50% in the lymphocytes of five of six patients so treated. Using lymphocytes obtained from 14 normal volunteers the concentration of free dipyridamole needed to inhibit the uptake of 1 microM cytidine by 50% averaged 13.8 +/- 1.1 nM. The plasma levels of alpha 1-acid glycoprotein, which tightly binds dipyridamole, ranged from 60 to 300 mg/dl in the patients in this study. As a consequence there were wide variations in the percentage of dipyridamole present as the unbound, pharmacologically active form and in the rates of dipyridamole clearance. The decreased rate of dipyridamole clearance seen in patients with high levels of alpha 1-acid glycoprotein resulted in higher plasma concentrations of total dipyridamole and compensated for the reduced fraction of free drug. Therefore, the plasma concentration of free dipyridamole varied much less than the total drug concentration in these patients. CTP synthetase and GMP synthetase activities were measured in patients' peripheral mononuclear cells prior to and at various times during therapy. CTP synthetase activity was inhibited in a time-dependent fashion by greater than 75% in seven of 13 evaluable courses; GMP synthetase was similarly inhibited in only three of ten cases. Ribonucleoside triphosphate pools were also measured in the patient's lymphocytes. CTP pool reductions of 30 to 50% were seen in nine of 19 courses, but in only four cases was the inhibition greater than 50%.(ABSTRACT TRUNCATED AT 400 WORDS)