Biomedical subjects

S Tapia

Publications and source records attributed to S Tapia.

9 recordsLinked to original sources

PubMed2006

Non-Hodgkin's lymphomas with Burkitt-like cells are associated with c-Myc amplification and poor prognosis.

Out of 344 patients with newly diagnosed non-Hodgkin's lymphoma (NHL), this study identified 16 patients presenting Burkitt-like cells (BLCs) after cytological and/or histological review. Conventional cytogenetic analysis showed at diagnosis complex chromosomal abnormalities in 13 cases and a normal karyotype in three cases. However, neither t(8;14)(q24;q32) nor the variants t(2;8)(p12;q24) or t(8;22)(q24;q11) was detected. FISH studies showed c-MYC amplification in all cases with four to more than seven copies in 10 - 77% metaphase or inter-phase cells. This study did not observe any gene fusion signal for c-MYC/IgH excluding a t(8;14) translocation and partial tri or polysomy of chromosome 8. It also excluded in that cases a break apart for the c-MYC locus. This study also never detected IgL/c-MYC, IgK/c-MYC or X-c-MYC. The BLCs were present whatever the lymphoma sub-type: follicular lymphoma (FL) was diagnosed in six out of 16 patients, mantle cell lymphoma (MCL) in four out of 16 patients, marginal zone lymphoma (MZL) in two out of 16 patients and diffuse large B-cell lymphomas (DLBCL) in three out of 16 patients. One additional patient presented a T-cell lymphoma. The clinical course was aggressive with a poor prognosis, as death occurred in nine patients, within 6 months after diagnosis for eight of them. These data could suggest a sub-group of NHL patients (15 B-NHL, 1 T-NHL) have been identified with a poor prognosis characterized by the association of Burkitt-like cells and c-MYC amplification without t(8;14)(q24;q32) or its variants. The possibility that this profile may represent a distinct morphologic NHL sub-set remains to be determined on a large cohort of patients.

Adult↗

PubMed2004

Chromosomal instability and ATR amplification gene in patients with persistent and polyclonal B-cell lymphocytosis (PPBL).

Forty-three patients with persistent and polyclonal B-cell lymphocytosis (PPBL) were studied. The PPBL diagnosis was based on the presence of a polyclonal lymphocytosis and the detection of binucleated lymphoid cells on peripheral blood examination. In order to define the cytogenetic profile in these patients, conventional cytogenetic analysis and fluorescence in situ hybridization were performed at diagnosis in all patients and also at follow-up in 10 patients. When excluding + i(3q) and PCC, chromosomal instability is a common occurrence in PPBL and is characterized by other independent clonal abnormalities, del(6q), + der(8) or + 8, polyploid karyotype, structural changes, aneuploidy and/or non clonal chromosomal aberrations with either loss or more frequently gain of chromosomes. These data show the presence of a chromosomal instability in 67.5% of PPBL patients. Finally, ATR amplification was detected by hybridization with BAC probe 26217 in + i(3q) positive metaphase cells. No ATR deletion was observed in the + i(3q) negative B-cells. As the natural history of PPBL remains unclear, it is necessary to diagnose PPBL patients and useful to recommend a careful and continued long follow-up in all PPBL patients.

Adult↗

PubMed1999

Improved outcome for acute lymphoblastic leukemia in children of a developing country: results of the Chilean National Trial PINDA 87.

BACKGROUND: The National Chilean Pediatric Oncology Group, PINDA, reports the first prospective, nonrandomized trial for acute lymphoblastic leukemia (ALL), using a modified version of the Berlin-Frankfurt-Munster protocol (ALL BFM 86). The aim of this study was to classify immunophenotypes, to decrease cranial irradiation, and to assess whether this protocol would improve the survival rate. PROCEDURE: From June, 1987, to June, 1992, 444 unselected children were diagnosed with ALL. Of them, 425 were evaluable. Therapy was stratified by risk. Standard-risk (SR) and high-risk (HR) patients received protocols I, M, II, and maintenance therapy. Very-high-risk (VHR) patients received protocol E instead of protocol M. All patients received a prephase treatment consisting of prednisone and intrathecal methotrexate (MTX). HR and VHR patients received cranial irradiation (12-18 Gy). The following changes were made to the ALL BFM 86 protocol: in protocol M, MTX 1 g/m2 instead of 5 g/m2; in protocol E, citarabine 1 g/m2 instead of 2 g/m2; mithoxantrone and ifosfamide were substituted by teniposide and cyclophosphamide. RESULTS: Immunophenotypes: pro-B-ALL, 14%; common ALL, 67.4%; pre-B-ALL, 4.3%; T-ALL, 10%; undifferentiated leukemia (AUL), 4.3%. The overall 5-year event-free survival (EFS) rate was 60% +/- 2% (SE). The 5-year EFS rate for each risk group was: SR 75%, HR 62%, VHR 28%, with a median follow-up of 6.5 years (range 4.5-9.5 years). The cumulative incidence of central nervous system (CNS) relapse was 5.4%. CONCLUSIONS: We have been able successfully to perform a nationwide study. Our strategy to adapt the BFM protocol to our population of patients trial was effective in improving the EFS. The immunophenotype distribution is similar to that in other reported series.

Adolescent↗

PubMed1995

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.

DNA-Binding Proteins↗

PubMed1992

The Wolf-Hirschhorn syndrome in fetuses.

Wolf-Hirschhorn syndrome (WHS) with partial deletion of the short arm of chromosome 4 has been exceptionally diagnosed in fetuses. We report prenatal diagnosis of five cases of monosomy 4p. The fetuses were karyotyped for severe intrauterine growth retardation (IUGR) diagnosed on routine ultrasound (US). In addition, cleft-lip and palate and diaphragmatic hernia respectively were found in two cases. The quantity of amniotic fluid was normal in all cases. At autopsy, the fetuses showed the typical craniofacial dysmorphy but without microcephaly. Major renal hypoplasia was the only constant visceral anomaly. Midline fusion defects were observed in all the fetuses, ranging from minor abnormalities such as scalp defect, hypertelorism, pulmonary isomerism, common mesentery, hypospadias and sacral dimple, to cleft palate, corpus callosum agenesis, ventricular septal defect, and diaphragmatic hernia. On post-mortem X-rays, a delayed bone age was always observed. All the placentae were hypotrophic, and two exhibited vascular lesions, although there was no maternal hypertension. Chromosomal studies showed that the breakpoints were within the 4p16 band in three cases, the 4p15 band in one case, and the 4p14 band in one case. The deletion was de novo in four cases, and resulted from a paternal translocation in one case. This study emphasizes the importance of karyotyping all fetuses with IUGR, especially when the quantity of amniotic fluid is normal, and suggests the possibility of recognizing on US the particular phenotype of WHS in utero.

Abnormalities, Multiple↗

PubMed1989

[Chorionic villi sampling. Results with the first 500 samples].

531 chorionic villi forceps biopsies were carried out, to look for genetic diseases. Sampling was impossible in 24 cases (4.5%). The following indications were chosen: maternal age over 38 years: 361 cases; parental chromosome abnormality: 28 cases; previous history of chromosome abnormality: 21 cases; X-linked disease: 77 cases; metabolic disease: 32 cases; hemoglobinopathy: 7 cases; blood group determination: 5 cases. An elective abortion was carried out in 44 cases (8.7%), whereas 465 pregnancies were not interrupted. Full term has been reached in 327 pregnancies. The rate of miscarriage in this group is 3.9% (13 miscarriages out of 327 pregnancies followed). The results obtained at the Saint-Vincent-de-Paul Hospital show that the cytogenetic technique is reliable, and that the low risk of sampling allows its application in the diagnosis of chromosome anomalies.

Adult↗

PubMed1988

Agyria--pachygyria and Miller-Dieker syndrome: clinical, genetic and chromosome studies.

Twelve cases of lissencephaly are reported. A high resolution chromosome study was performed on each in order to detect small chromosomal anomalies, undetectable with routine techniques. Only one case was shown to have an unbalanced karyotype with a microdeletion of the short arm of chromosome 17 (del 17p). This child also had symptoms of the Miller-Dieker syndrome, consisting of lissencephaly, characteristic facies, pre- and post-natal growth retardation and other birth defects. As proposed by Dobyns, it seems justifiable to classify lissencephalies into four different groups, according to other clinical manifestations and results of chromosome studies.

Cerebral Cortex↗

PubMed1988

Interstitial dup(1p) and severe intrauterine growth retardation.

An 1,860 g baby girl was born spontaneously after a 38 weeks pregnancy with important foetal hypotrophy and died at 6 weeks of life. She had an inverted duplication of a small part of the short arm of chromosome 1p:46, XX, inv dup(1) (pter p31::p11p13::p31 ter). This observation is compared to three others reported in the literature with intrachromosomal duplication of 1p.

Chromosome Aberrations↗

PubMedDate not supplied

[Enteroparasitoses in children from the V Region. A study in the Juan Fernandez archipelago, Chile].

The results of two enteroparasitological surveys in children carried out in the Juan Fernandez Archipelago, within a 5-year period (1982-1987), are compared. In both studies the absence of Ascaris lumbricoides has been persistent, having no explanation for this phenomenon due to the favorable environmental conditions for the development of the quoted parasite. In the second survey Cryptosporidium sp. was studied, finding a higher frequency than that detected in rural areas of the V Region.

Child↗