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Y Alvarez

Publications and source records attributed to Y Alvarez.

At least 19 recordsLinked to original sources
PubMed2005

Genetic abnormalities associated with the t(12;21) and their impact in the outcome of 56 patients with B-precursor acute lymphoblastic leukemia.

The ETV6/RUNX1 rearrangement is found in 20-30% of children with B-cell precursor acute lymphoblastic leukemia and is associated with a good outcome. To determine the cytogenetic and molecular abnormalities associated with the ETV6/RUNX1 rearrangement and the influence of this rearrangement in patients' evolution, we analyzed the molecular cytogenetic profiles of 56 children with this rearrangement and B-cell precursor acute lymphoblastic leukemia. Secondary changes detected with conventional cytogenetics and with fluorescence in situ hybridization were found in 71.4% of cases, the most frequent being the loss of the normal ETV6 allele, 12p aberrations, duplication of the fusion gene, and trisomy 21, as in replicating the results of previous studies. In this preliminary series, with a mean follow-up of 69.3 months, secondary abnormalities did not influence patients' outcome. It seems therefore that the prognostic value of the t(12;21) does not vary and that ETV6/RUNX1 rearrangement is an independent indicator of good prognosis.

Child↗
PubMed2005

[Metamphetamine].

Explore the source record for details and available documents.

Amphetamines↗
PubMed2004

ETV6/RUNX1 rearrangement in childhood B-precursor acute lymphoblastic leukemia with normal karyotypes or without cytogenetic results.

The ETV6/RUNX1 rearrangement (also known as TEL/AML1) was evaluated in 39 children with B-precursor acute lymphoblastic leukemia (ALL) who had a normal karyotype or lack of mitoses. Forty-one point six percent of patients with normal karyotypes and 66.6% of patients without mitoses presented with the ETV6/RUNX1 rearrangement. In addition to this rearrangement, eight patients showed loss of the normal ETV6 allele; of three patients without mitoses, two showed an extra signal of the RUNX1 gene and the third showed the fusion gene duplicated and loss of the normal ETV6 allele. One patient without the ETV6/RUNX1 rearrangement and without mitoses showed two extra signals of the RUNX1 gene.

Child↗
PubMed2004

Influence of hepatocyte-rich liver cell mixture and liver fibroblasts on prolonging graft islet survival in rats without immunosuppressive drugs.

BACKGROUND: We noted that a liver cell suspension, made up of a mixture of several kinds of hepatic cells, affected allogenic islet survival when it was transplanted into the liver, mixed with the islets or separately. AIM: To study if this effect was related to a liver cell mixture rich in hepatocytes (hp) or to liver fibroblasts (fb). METHODS: We studied 14 groups of rats: (A) a sham group with saline; (B) a group receiving transplantation with hepatic cells alone; (C) a control group, with islets alone via the portal vein, without hepatic cells (hp or fb). For the other groups, we used a different ratio of cells/islets (100 : 1, 150 : 1 and 200 : 1) and different co-transplantation techniques with both types of cells. For the D, E, J groups, a mixture of hepatocytes (hepatocyte-rich liver cell mixture) or fibroblasts with islets was injected into the portal vein. For the other groups, we used a sequential procedure with a 15 minute interval between a first injection of hp or fb into the portal vein or into the vena cava, and a second injection of islets always into the portal vein; thus, it was a sequential portal/portal procedure with hepatocyte-rich liver cell mixture (hp) (F, G) or fibroblasts (K, L) and a sequential cava/portal with hp (H, I) or fibroblasts (M, N). RESULTS: Most of the co-transplantation groups showed functional islets (blood glucose < 250 mg/dl) on the first or second day of transplantation; after several days they once again had high glucose levels, though not as high as pre-transplantation. There was statistical significance (p < 0.001) between the presence or not of hepatic cells to obtain prolongation of graft survival (blood glucose < 250 mg/dl). Statistical significance (p < 0.001) was found for several sequential groups with hp (F, I) and fb (K, L). It was also remarkable that 3 rats (37.5 %) from the I group (sequential cava/portal with hp/islets 200 : 1) were euglycemic (blood glucose < 150 mg/dl) for more than 3 months. ANOVA showed a large interaction between the type of transplant performed and the cellular ratio used, with a significance of p < 0.001. Histological studies in rats with prolonged euglycemia, showed insulin-producing cell aggregates in the liver, while there was a remarkable decrease in insulin-producing cells in the remaining islets of pancreatic tissue. CONCLUSION: The results showed a marginal prolongation of islet graft survival when they are co-transplanted with a hepatocyte-rich liver cell mixture or with liver fibroblasts. The mechanism does not seem to be a cellular interaction between different hepatic cells and islets, but some kind of cellular interaction or released factor from either two cell types on the immune system, blocking or modulating it, at least temporarily.

Analysis of Variance↗
PubMed1999

Phylogeography of African fruitbats (Megachiroptera).

Joint sequences from the mitochondrial cytochrome b and 16S rRNA genes of a wide representation of Megachiroptera were employed to evaluate the traditional taxonomic arrangement of African fruitbats and to examine their origins and evolutionary relationships. The resulting phylogenetic hypotheses are inconsistent with the previously established morphology-based subdivisions of Megachiroptera at the suprageneric level. Findings indicate the existence of an African clade, which appears to be formed by two endemic clades: the epomophorines and the myonycterines. According to our topologies, the genus Rousettus is monospecific in mainland Africa. Its traditional subgenera Stenonycteris and Lissonycteris appear closer to the myonycterines than to Rousettus. Topologies also indicate that the African genus Eidolon is not phylogenetically related to any other African fruitbat. It would seem that the arrival of fruitbats in Africa was a complex process involving at least three independent colonization events. One event took place probably in the Miocene via forested corridors that connected the African and Asian rain forest blocks, as for other groups of mammals. The resulting lineage diversified into most of the extant African fruitbats. Related to this clade, the Rousettus species group is thought to have arrived in Africa in more recent times, possibly by progressive displacement from the East through India. Finally, the present topologies suggest an independent colonization of Africa by ancestors of Eidolon.

Africa↗
PubMed1999

Molecular phylogeny and morphological homoplasy in fruitbats.

The present study evaluates the evolutionary framework of the Old World fruitbats based on the cytochrome b and 16S rRNA mitochondrial gene sequences from a wide range of taxa. Phylogenetic analyses indicated that morphology-based subfamilies and most suprageneric groups are nonnatural assemblages. They also support the existence of an endemic African clade of fruitbats. The discrepancy between the evolutionary relationships yielded by molecular and morphological data sets may be, at least in part, explained by the recurrent retention of primitive morphology (Rousettus-like) across different lineages. The maintenance of primitive characters in different groups of flying foxes, as well as morphological convergence in nectar-feeding bats and possibly also in short-muzzle bats, may have led to high levels of homoplasy, resulting in misleading taxonomic arrangements. This may be particularly so with respect to high taxonomic levels based on morphological characters.

Africa↗
PubMed1979

Exogenous DNA transcription in cells with their native DNA inhibited. 1. DNA incorporation into homologous and heterologous cells.

The incorporation of mouse S-EAC DNA into homologous normal cells (mouse embryo secondary cultures), and into heterologous cancer cells (TC-SV40 line), with both systems having their native DNA blocked by BrUdR incorporation, was studied. 3H-TdR-DNA was inoculated with DEAE-D to protect it and to potentiate its incorporation, the process being autoradiograohically controlled. The amount of incorporated DNA was radioisotopically determined, and the incorporation process was studied by analysing the fractions obtained after density gradient centrifugation separation of the inoculated cells DNA. Receptivity was greater in those cells inoculated with DEAE-D-protected DNA. The incorporation was slightly greater for cells whose DNA had been blocked by BrUdR incorporation, and for homologous with respect to heterologous cells. In those cells inoculated while the DNA blockade was incomplete, part of the inoculated DNA became incorporated into the cell genome (L-H chains). However, in the completely blocked cells it could not be determined if the incorporation occurred in a lysogenic-like or in an episomic-like form.

Animals↗