Limiting shapes of confined lipid vesicles.

We theoretically study the shapes of lipid vesicles confined to a spherical cavity, elaborating a framework based on the so-called limiting shapes constructed from geometrically simple structural elements such as double-membrane walls and edges. Partly inspired by numerical results, the proposed non-compartmentalized and compartmentalized limiting shapes are arranged in the bilayer-couple phase diagram which is then compared to its free-vesicle counterpart. We also compute the area-difference-elasticity phase diagram of the limiting shapes and we use it to interpret shape transitions experimentally observed in vesicles confined within another vesicle. The limiting-shape framework may be generalized to theoretically investigate the structure of certain cell organelles such as the mitochondrion.

RHD allelic identification among D-Brazilian blood donors as a routine test using pools of DNA.

BACKGROUND: RHD alleles leading to a reduced expression of D antigen of the red blood cell (RBC) surface may be erroneously typed as D- by serology and may cause anti-D immunizations when transfused to recipients. METHODS: To determine the occurrence of such alleles among apparent D- blood donors, molecular typing was implemented as a routine test using a pool of DNA. A total of 2,450 pretyped D- samples were tested in pools of 10 for the RHD-specific polymorphism in intron 4 and exon 7. Samples in polymer chain reaction (PCR) positive pools were individually reevaluated by exon-specific PCRs, sequencing, and serologic methods. RESULTS: Among 2,450 serologically D- blood donor samples tested, 101 (4.1%) carried the RHD gene. Nonfunctional RHD (RHDψ, RHD*CE(2-9)-D, and RHD*CE(3-7)-D), different weak D alleles such as RHD*weak D type 1, RHD*weak D type 4.3, RHD*weak D type 5, RHD*weak D type 38, and RHD*DEL were identified. CONCLUSION: We employed a PCR-based assay for RHD as a routine test using pools of ten DNA blood donor samples. The integration of RHD genotyping into the routine screening program using pools of DNA samples was straightforward. As a consequence, 19 (0.8%) blood donors carrying a weak D and Del phenotypes with the potential of causing anti-D immunizations in recipients were reclassified as D+. For each population, it would be necessary to adapt the RHD genotyping strategy to the spectrum of prevalent alleles.

The octadecaneuropeptide exerts an anxiogenic-like action in goldfish.

I.c.v. administration of the octadecaneuropeptide (ODN), a peptide derived from diazepam-binding inhibitor (DBI), induces anorexigenic and anxiogenic-like actions in rodents. We have recently shown that, in goldfish, i.c.v. injection of ODN also reduces food consumption via the metabotropic endozepine receptor. However, there is little information regarding the structure of DBI and the psychophysiological roles of endozepines in fish. Therefore, in the present study, we isolated and cloned a cDNA encoding goldfish DBI. The deduced sequence exhibits high similarity with non-mammalian DBIs, and we investigated the effect of homologous ODN on psychomotor activity in goldfish. i.c.v. injection of synthetic goldfish ODN at 10 pmol/g body weight (BW) stimulated locomotor activity. Since intact goldfish placed in a tank with both black and white background areas prefers the black compartment, we developed a method for measuring the time taken for fish to move from the black to the white area. I.c.v. administration of diazepam (35 and 350 pmol/g BW) decreased, whereas i.c.v. administration of ODN (10 pmol/g BW) or the central-type benzodiazepine receptor inverse agonist FG-7142 (9 pmol/g BW) increased the time taken to move from the black to the white background area. The anxiogenic-like effect of ODN was blocked by the central-type benzodiazepine receptor antagonist flumazenil (100 pmol/g BW), but was not affected by the metabotropic endozepine receptor antagonist cyclo1-8[d-Leu(5)]octapeptide (100 pmol/g BW). These data indicate that ODN can potently affect locomotor and psychomotor activities in goldfish and that this action is mediated via the central-type benzodiazepine receptor-signaling pathway.

Autoantibody formation after alloimmunization inducing bystander immune hemolysis.

The development of RBC autoantibodies resulting from or associated with allogeneic blood transfusions is not an easily determined complication of RBC transfusions. This report discusses one patient who developed RBC autoantibodies in association with an allogeneic blood transfusion and alloimmunization leading to a temporary bystander immune hemolysis. A 72-year-old woman was hospitalized as a result of severe anemia and received two units of ABO- and D-compatible RBCs. She had a history of two pregnancies 40 years before, but no history of RBC transfusion, and her antibody screen was negative. On the tenth day after transfusion her hemoglobin dropped, and alloanti-c was identified in her serum and eluate. At this time she received another two units of compatible blood according to her phenotype (group O, R1R1, K:-1). After 48 hours, she developed joint pain, pyrexia, and hemoglobinuria, and her Hb dropped from 9.2 g/dL to 5.3 g/ dL. The direct antiglobulin test was positive, an IgG autoantibody was present in the eluate, and the antibody investigation revealed the presence of anti-Jk(b) in addition to the previously identified alloanti-c. Her genotype was determined, and, based on the findings, two additional units were selected, found to be compatible, and transfused without incident. Transfusions were discontinued, and she was treated with IVIG and corticosteroids. Her Hb increased to 9.7 g/dL, and the patient made an uneventful recovery. It was concluded that transfusion of incompatible RBCs induced the formation of an autoantibody in this patient, resulting in lysis of bystander RBCs. The need for additional blood transfusion was successfully avoided by treatment with IVIG, steroid therapy, and rituximab.

Aplicações da genotipagem de grupos sanguíneos / Applications of blood group genotyping

A possibilidade de realizar tipagem de grupos sangüíneos por DNA pode facilitar a resolução de problemasclínicos que não são solucionados pela hemaglutinação, aumentando assim a segurança dos pacientes transfundidos. Agenotipagem de grupos sangüíneos pode ser aplicada nas seguintes situações (a) tipagem de antígenos para os quais não há disponibilidade de anti-soros comerciais, (b) tipagem de pacientesrecentemente transfundidos e/ou que apresentam teste direto da antiglobulina positivo, (c) identificação de fetos de risco de mães RhD-negativo, (d) tipagem de doadores para aumentar o estoque de sangue raro para as transfusões. O objetivo desta revisão é apresentar as aplicações da genotipagem de grupos sangüíneos na medicina transfusional e materno-fetal e discutir os problemas clínicos que potencialmente podem ser resolvidospelas técnicas moleculares. A base de dados utilizada nesta revisão foi a busca no MEDLINE e por meio de revisão das referências bibliográficas. Todos os trabalhos e revisões incluídos abrangeram a segurança transfusional e materno-fetal, as bases moleculares dos antígenos de grupos sangüíneos e as aplicações da genotipagem na práticaclínica. Os dados foram coletados através da avaliação dos resultados de estudos e revisões de polimorfismosde grupos sangüíneos e suas aplicações na clínica.

Breast cancer. Cyr61 is overexpressed, estrogen-inducible, and associated with more advanced disease.

To identify genes involved in breast cancer, polymerase chain reaction-selected cDNA subtraction was utilized to construct a breast cancer-subtracted library. Differential screening of the library isolated the growth factor-inducible immediate-early gene Cyr61, a secreted, cysteine-rich, heparin binding protein that promotes endothelial cell adhesion, migration, and neovascularization. Northern analysis revealed that Cyr61 was expressed highly in the invasive breast cancer cell lines MDA-MB-231, T47D, and MDA-MB-157; very low levels were found in the less tumorigenic MCF-7 and BT-20 breast cancer cells and barely detectable amounts were expressed in the normal breast cells, MCF-12A. Univariate analysis showed a significant or borderline significant association between Cyr61 expression and stage, tumor size, lymph node positivity, age, and estrogen receptor levels. Interestingly, expression of Cyr61 mRNA increased 8- to 12-fold in MCF-12A and 3- to 5-fold in MCF-7 cells after 24- and 48-h exposure to estrogen, respectively. Induction of Cyr61 mRNA was blocked by tamoxifen and ICI182,780, inhibitors of the estrogen receptor. Stable expression of Cyr61 cDNA under the regulation of a constitutive promoter in MCF-7 cells enhanced anchorage-independent cell growth in soft agar and significantly increased tumorigenicity and vascularization of these tumors in nude mice. Moreover, overexpression of Cyr61 in MCF-12A normal breast cells induced their tumor formation and vascularization in nude mice. In summary, these results suggest that Cyr61 may play a role in the progression of breast cancer and may be involved in estrogen-mediated tumor development.

Plasma levels of the differentiation inhibitory factor nm23-H1 protein and their clinical implications in acute myelogenous leukemia.

A previous study reported that a nondifferentiating myeloid leukemia cell line produced differentiation-inhibiting factors. One of the factors was purified as a homologue of the nm23 genes. The nm23 genes were overexpressed in acute myelogenous leukemia (AML) cells, and a higher level of nm23 gene expression was correlated with a poor prognosis in AML. The present study determined the plasma levels of nm23-H1 protein by enzyme-linked immunosorbent assay and assessed the association between this level and the clinical outcome in 102 patients with AML. The plasma concentration of nm23-H1 was higher in patients with AML than in normal controls (P =.0001). Plasma nm23-H1 levels were correlated with the product of the intracellular nm23 messenger RNA (mRNA) level and the white blood cell count, but not with the mRNA level alone. Therefore, nm23-H1 plasma levels probably depend on the total mass of leukemic cells overexpressing the nm23-H1 gene. Overall survival was lower in patients with higher plasma nm23-H1 levels than in those with lower levels. Multivariate analysis using the Cox proportional hazard model showed that elevated plasma nm23-H1 levels significantly contributed to the prognosis of AML patients. Furthermore, the plasma nm23-H1 levels were investigated in 70 patients with other hematologic neoplasms, including 6 with acute lymphoblastic leukemia, 13 with chronic myelogenous leukemia, and 12 with myelodysplastic syndrome. Plasma nm23-H1 levels were significantly higher in all of these hematologic neoplasms than in normal controls. Increased plasma levels of nm23-H1 may have prognostic value in these hematologic malignancies as well as in AML.

Plasma kinetics of an artificial emulsion resembling chylomicrons in patients with chronic lymphocytic leukemia.

Chylomicrons are the lipoproteins that transport dietary lipids in the blood. Although neoplastic diseases are often accompanied by alterations in lipid metabolism, chylomicrons are scarcely explored in cancer, despite their importance for the body's energy supply. Moreover, no data are available regarding chylomicron metabolism in chronic lymphocytic leukemia (CLL). Chylomicron metabolism in the bloodstream consists of lipolysis by lipoprotein lipase and uptake of remnants by the liver and is difficult to assess in the human body. Among the methods to evaluate this pathway, the determination of the plasma kinetics of triglyceride-rich emulsions that mimic chylomicrons is a practical and straightforward approach. A double-labeled chylomicron-resembling emulsion was injected into 10 patients with CLL and into 11 normolipidemic healthy subjects. The plasma kinetic curves of the emulsion 3H-triglyceride and 14Ccholesteryl ester were determined in plasma samples collected over 30 min. The fractional clearance rate (FCR) of triglycerides in CLL was not changed compared with controls. The FCR of cholesteryl esters was also no different from controls. These results indicate that chylomicron lipolysis and remnant removal are not affected in CLL.

Loss of p73 gene expression in leukemias/lymphomas due to hypermethylation.

The p73 gene, a member of the p53 family, is a new candidate tumor suppressor gene. To investigate the possibility of genetic alteration of p73 in leukemia and lymphoma, we examined 55 cell lines and 39 patient samples together with 17 nonhematopoietic cancer cell lines. Gene expression of p73 was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in cell lines (5 of 7 pre B/B-acute lymphoblastic leukemia [ALL], 13 of 21 T-ALL/lymphoblastic lymphomas [LBL], 9 of 10 B-non-Hodgkin's lymphomas [B-NHL], 8 of 9 acute myelogenous leukemias [AML], 2 of 2 T-NHL, 3 of 3 multiple myeloma), and in patient samples (16 of 23 pre B-ALL, 5 of 8 T-ALL/LBL, 5 of 8 B-NHL). PCR-single-strand conformation polymorphism (SSCP) of cDNAs showed no mutation in 43 p73-expressing cell lines within the regions that corresponded to the 5 mutational hotspots of the p53 gene. Neither homologous deletion nor rearrangement of the p73 gene were found by Southern blot analysis in any of the cell lines that lack expression of p73. In contrast to prior published data, analysis of a polymorphic site showed that the p73 gene was expressed biallelically in cell lines and normal peripheral blood. Notably, the p73-negative cell lines were hypermethylated at a CpG island in the 5' untranslated region of the p73 mRNA, and treatment of these cell lines with 5-azacytidine (5-AC), a demethylation reagent, induced p73 expression. Taken together, we found that a sizable proportion (32%) of ALL/B-NHL cell lines and primary tumors had negligible or limited expression of the p73 gene associated with hypermethylation of the gene. These findings suggest that silencing of the p73 gene by hypermethylation may contribute to development and/or progression of lymphoid neoplasms.

Mixed-lineage leukemia with t(10;11)(p13;q21): an analysis of AF10-CALM and CALM-AF10 fusion mRNAs and clinical features.

A fusion transcript of AF10 and CALM was isolated recently from the U937 cell line with t(10;11)(p13;q21). We performed reverse transcription-polymerase chain reaction and sequencing analysis on the t(10;11) leukemia samples obtained from four patients and one cell line, and we identified reciprocal fusion transcripts of AF10 and CALM in all the samples. The fusion transcripts in the five samples showed four different breakpoints in AF10 and three different breakpoints in CALM. In addition, the fusion transcripts in one sample showed a nucleotide sequence deletion in AF10, and those in two samples showed a nucleotide sequence deletion in CALM; the deletions were thought to be caused by alternative splicing. The variety of breakpoints and splice sites in the two genes resulted in five different-sized AF10-CALM mRNAs and in four different-sized CALM-AF10 mRNAs. Clinical features of 11 patients, including 6 of our own and 5 reported by others, in whom the fusion of AF10 and CALM was identified, are characterized by young age of the patients, mixed-lineage immunophenotype with coexpression of T-cell and myeloid antigens, frequent occurrence of a mediastinal mass, and poor clinical outcome.

Cyclin A1 expression in leukemia and normal hematopoietic cells.

Human cyclin A1 is a newly cloned, tissue-specific cyclin that is prominently expressed in normal testis. In this study, we showed that cyclin A1 was highly expressed in a subset of leukemia samples from patients. The highest frequency of cyclin A1 overexpression was observed in acute myelocytic leukemias, especially those that were at the promyelocyte (M3) and myeloblast (M2) stages of development. Cyclin A1 expression was also detected in normal CD34(+) progenitor cells. The expression of cyclin A1 increased when these cells were stimulated to undergo myeloid differentiation in vitro. Taken together, our observations suggest that cyclin A1 may have a role in hematopoiesis. High levels of cyclin A1 expression are especially associated with certain leukemias blocked at the myeloblast and promyelocyte stages of differentiation.

Evaluation by multivariate analysis of the differentiation inhibitory factor nm23 as a prognostic factor in acute myelogenous leukemia and application to other hematologic malignancies.

The differentiation inhibitory factor nm23 can inhibit the differentiation of murine and human myeloid leukemia cells. We recently reported that nm23 genes were overexpressed in acute myelogenous leukemia (AML), and a higher level of nm23-H1 expression was correlated with a poor prognosis in AML, especially in AML-M5 (acute monocytic leukemia). To evaluate the importance of nm23 expression as a prognostic factor in AML, we compared it with other putative prognostic factors in AML. An analysis of the correlation between nm23 expression and the clinical parameters of 110 patients with AML demonstrated that increased nm23-H1 mRNA levels were associated with resistance to initial chemotherapy and with reduced overall survival. Multivariate analysis using Cox's proportional hazard model also showed that elevated nm23-H1 mRNA levels significantly contributed to the prognosis of patients with AML. Especially in AML-M5, nm23-H1 status was the most important prognostic factor. Furthermore, to determine whether we can apply the results observed in AML to other hematologic malignancies, we investigated the relative levels of nm23-H1 and nm23-H2 transcripts in 149 patients with hematologic neoplasms, including 110 with de novo AML, 9 with de novo acute lymphoblastic leukemia, 14 with myelodysplastic syndrome, 16 with chronic myelogenous leukemia (CML), and 5 normal subjects by the reverse transcriptase-polymerase chain reaction. Expression of nm23-H1 was significantly higher in all the hematologic neoplasms, except CML in chronic phase, than in normal blood cells. nm23 may have a prognostic effect in these hematologic malignancies as well as in AML.

Novel MLL-CBP fusion transcript in therapy-related chronic myelomonocytic leukemia with a t(11;16)(q23;p13) chromosome translocation.

CBP, which is located on 16p13 and encodes a transcriptional adaptor/coactivator protein, has been shown to fuse by the t(8;16)(p11;p13) translocation to MOZ on 8p11 in acute myeloid leukemia. We found a t(11;16)(q23;p13) in a child with therapy-related chronic myelomonocytic leukemia. Subsequent reverse transcriptase-polymerase chain reaction and direct sequencing analyses revealed the MLL-CBP fusion transcript in CMML cells. Because 11q23 translocations involving MLL and t(8;16) involving MOZ and CBP have been reported in therapy-related leukemias, both the MLL and CBP genes may be targets for topoisomerase II inhibitors. Accordingly, we believe that most t(11;16)-associated leukemias may develop in patients who have been treated with cytotoxic chemotherapy for primary malignant diseases.

Minimal residual disease in acute monocytic leukemia patient with trisomy 11 and partial tandem duplication of MLL.

We studied MLL rearrangements in five patients with myeloid hematologic malignancies with trisomy 11. Two had acute monocytic leukemia (AMoL), one had chronic myelomonocytic leukemia, one had refractory anemia, and the other had juvenile chronic myelogenous leukemia. Only one patient, a 15-year-old boy with AMoL and simple trisomy 11, showed rearrangement of MLL. He did not respond to chemotherapy, and successfully underwent bone marrow transplantation, but suffered a relapse 22 months later. Reverse transcription-polymerase chain reaction (RT-PCR) and sequencing analyses of bone marrow cells revealed a tandem duplication of MLL, and his relapse was predictable by sequential RT-PCR studies before it was clinically evident. Of 16 acute myeloid leukemia patients with trisomy 11 and rearrangement of MLL reported, our patient was the youngest in age and the only one with AMoL.

Criopreservaçäo de medula óssea e células pluripotentes periféricas utilizando um congelador programável: experiência em 86 congelamentos / Cryopreservation of bone marrow and peripheral blood stem cells using a controlled rate freezing system: experience on 86 procedures

A infusao de células hematopoéticas totipotentes criopreservadas permite a recuperaçao da hematopoese após quimioterapia mieolblativa. Objetivo. A formaçao de cristais de gelo durante o processo de congelamento é o fator principal que causa ruptura das estruturas celulares. A criopreservaçao dessas células a uma taxa constante preveniria os danos causados pelo congelamento brusco. Métodos. Vinte e três pacientes com mediana de 25 anos (variaçao 3-57) tiveram a medula óssea e/ou células-tronco periféricas (CTP) coletadas no período de março de 1993 a outubro de 1994, totalizando 86 congelamentos. Os pacientes apresentavam as seguintes neoplasias: linfoma nao-Hodgkin (n=5), leucemia mielóide aguda (n=8), leucemia linfóide aguda (n=6), doença de Hodkin (n=3) e mieloma múltiplo (n=1). O congelamento foicontrolado por um computador, acoplado ao sistema, às seguintes temperaturas: -1 graus Celsius/min até -45 graus Celsius e depois a -10 graus Celsius/min até -80 graus Celsius. Após o congelamento, as células foram mantidas em freezer a -110 graus Celsius até o momento da infusao. Para obtençao das CTP, empregou-se o fator de crescimento estimulante de granulócitos (G-CSF). Resultados. Uma mediana de 3,16 x 10(8) céls./kg (variaçao 0,86-24,22) de CTP e 2,03 x 10(8) céls./kg (variaçao 0,19-12,21) de medula óssea foi congelada. A mediana para atingir granulócitos maior ou igual a 500/muL e plaquetas maior que 20.000/muL foi de 12 dias (variaçao 8-40) e 31 dias (variaçao 8-80), respectivamente. Todos os pacientes tiveram recuperaçao hematopoética após a infusao das células criopreservadas. Conclusao. A criopreservaçao em congelador program vel permite o armazenamento de células hematopoéticas e, potencialmente, pode causar menor dano celular.

[Cryopreservation of bone marrow and peripheral blood stem cells using a controlled rate freezing system: experience with 86 procedures]. / Criopreservação de medula óssea e células pluripotentes periféricas utilizando um congelador programável: experiência em 86 congelamentos.

UNLABELLED: The cryopreservation of hematopoietic stem cells can be used for rescuing the hematopoiesis after high dose chemotherapy. PURPOSE: The ice crystal formation during the freezing procedure is the key point that can be harmful to the cells. The cryopreservation of hematopoietic stem cells in a controlled-rate freezer could decrease the cell damage. METHODS: Twenty-three patients with a median age of 26 years (range 03-57) had bone marrow and/or peripheral blood stem cells harvested from March 1993 through October 1994, ending up to 86 freezing procedures. The patient's diagnoses are as follows: Non-Hodgkin's Lymphoma (n = 5); Acute Myelogenous Leukemia (n = 8); Acute Lymphocytic Leukemia (n = 6); Hodgkin's disease (n = 3); Multiple Myeloma (n = 1). The cells were frozen away in a controlled-rate freezer chamber at the following rate: -1 degree C/min from room temperature to -45 degrees C and then, at -10 degrees C/min down to -80 degrees C. After freezing, the cells were kept into mechanical freezers until the marrow infusion. To mobilize PBSC (peripheral blood stem cells), G-CSF (granulocyte colony stimulating factor) was given. RESULTS: A median of 3.16 x 10(8) cells/kg (range 0.86-24.22) of PBSC and 2.03 x 10(8) cells/kg (0.19-12.21) of bone marrow cells were frozen. The median time to reach granulocytes greater than 500/microL and platelets greater than 20,000/microL was 12 days (range 8-40) and 31 days (range 8-80), respectively. All patients had marrow engraftment after infusion of hematopoietic stem cells. CONCLUSION: The cryopreservation procedure using a controlled-rate freezer can store hematopoietic stem cells and potentially, cause less damage to the cells.

An increased NM23H1 copy number may be a poor prognostic factor independent of LOH on 1p in neuroblastomas.

In a study of 154 neuroblastomas, loss of heterozygosity (LOH) was observed on 1p (13%, 19/143), 11q (19%, 11/59), 14q (15%, 15/97), 17p (5%, 5/105) and 17q (17%, 9/52). We also found an increase in NM23H1 copy number in 14% (13/95) of neuroblastomas. All except one tumour with an increased copy number stained positive with anti-NM23H1 monoclonal antibody. Event-free survival (EFS) was significantly shorter in 19 patients with LOH on 1p than in 128 without (41% vs 77% 4 year EFS, P=0.0093), and in 13 patients with increased NM23H1 copy numbers than in 82 with normal copy numbers of the gene (61% vs 84% 4 year EFS, P=0.0103). LOH on 11q, 14q or 17q did not affect EFS. Most tumours with LOH on 1p, increased NM23H1 copy numbers or MYCN amplification occurred in patients aged 12 months or more, those with advanced stage disease, and those who showed near diploidy or pseudodiploidy. However, LOH on 1p was found in only 1 of the 13 tumours with increased NM23H1 copy numbers, and MYCN amplification of four copies occurred in only one other such tumour. These findings suggest that the increased NM23H1 copy number may be a predictor for poor prognosis, independent of LOH on 1p, and probably also of MYCN amplification.

Differentiation inhibitory factor nm23 as a new prognostic factor in acute monocytic leukemia.

Differentiation inhibitory factor (nm23 protein) inhibited the induction of differentiation of mouse myeloid leukemia M1 and WEHI-3BD+ and human erythroleukemia HEL, KU812, and K562 cells. Block of differentiation may be associated with the aggressive behavior of leukemia. To examine the role of nm23 in human myeloid leukemia, we investigated the relative levels of nm23-H1, nm23-H2, and c-myc transcripts in 42 patients with acute myelogenous leukemia (AML), and in 5 with chronic myelogenous leukemia at chronic phase by reverse transcriptase polymerase chain reaction. The expression of nm23-H1 and -H2 but not of c-myc in AML was significantly higher than that in normal blood cells. Among AMLs, acute monocytic leukemia (presentation with AML-M5 morphology) was especially associated with elevated nm23-H1 and -H2 mRNA levels. On the other hand, the elevated levels of c-myc expression in AML-M5 were less evident. An analysis of correlation between nm23 expression and clinicopathological parameters showed that resistance to initial chemotherapy is associated with increased nm23-H1 mRNA levels and that a high initial white blood cell count is associated with increased nm23-H2 mRNA levels. Elevated nm23-H1 mRNA levels were associated with significantly reduced the overall survival of AML, especially of AML-M5 patients. The present results indicate that nm23-H1 and -H2 are overexpressed in AML and especially nm23-H1 gene expression predicts the prognosis of AML, especially of AML-M5.

The der(21)t(12;21) chromosome is always formed in a 12;21 translocation associated with childhood acute lymphoblastic leukaemia.

We studied 116 patients (93 children and 23 adults) with acute lymphoblastic leukaemia (ALL) using fluorescence in situ hybridization (FISH) with the yeast artificial chromosome (YAC) clone, 964c10, which includes the recently described ETS-like gene, TEL, on 12p13. FISH revealed that nine of the patients had a t(12;21), which had not been previously detected. The nine patients were all children, seven boys and two girls, aged 1-10 years (median 3 years), had an early B immunophenotype, and achieved complete remission, although two of them experienced haematological relapse. In addition to the t(12;21), FISH also revealed that three of the nine had a del(12p) in the other homolog of chromosome 12 or in the der(12) chromosome itself, and that two others had 12p translocations in the other chromosome 12 homolog. Although chromosomal rearrangements associated with the t(12;21) were heterogenous and complex, fusion of the sequences from chromosomes 12 and 21 on the der(21)t(12;21) chromosomes was consistent, suggesting that the TEL-AML1 gene fusion on the der(21) chromosome may be critical in leukaemogenesis and that FISH or reverse transcriptase-polymerase chain reaction (RT-PCR) targeted to the chimaeric sequences on the der(21) will be most useful in detecting the t(12;21) or following a patient with the t(12;21), which is one of the most frequent chromosomal rearrangements in both Caucasian and Asian childhood ALL.

Disappearance of AML1-MTG8(ETO) fusion transcript in acute myeloid leukaemia patients with t(8;21) in long-term remission.

In a study of 23 patients with t(8;21)-associated acute myeloid leukaemia the AML1-MTG8 fusion transcript was present in the majority of serial samples obtained from 17 patients followed for up to 34 months after diagnosis, but was absent in samples from all six patients who had been in continuous complete remission for 61 months after allogeneic bone marrow transplantation (BMT), or for 52, 53, 123, 182 and 198 months, respectively, after courses of intensive chemotherapy. Previous studies showed that the AML1-MTG8 fusion transcript was present in most patients with this type of translocation in long-term remission. Our results indicate that blood cells of patients with t(8;21) in remission of over 10 years may not show the AML1-MTG8 fusion transcript, and that those of patients who have undergone allogeneic BMT or intensive chemotherapy may become fusion transcript-negative much earlier. Our study suggests that leukaemic cells with the AML1-MTG8 fusion transcript may survive for some time after courses of chemotherapy or BMT, but that they may eventually be eradicated by immunologic and other antileukaemic mechanisms.