Detection of numerical chromosome anomalies in interphase cells of benign and malignant thyroid lesions using fluorescence in situ hybridization

Benign and malignant thyroid tumors constitute a wide range of neoplasias showing recurrent chromosome abnormalities. In an attempt to characterize specific numerical chromosome abnormalities in thyroid tissues, We present here the findings from a study of archival samples depicted by 10 malignant tumors, 30 benign lesions, and 10 normal thyroid tissues. Fluorescence in situ hybridization was performed on noncultured samples using biotinylated centromere-specific probes for chromosomes 7, 10, and 17. Trisomy or tetrasomy 7 were present in 19 benign and in 7 malignant tumors. Trisomy 10 or 17 were observed in 18 adenomas or goiters and in 9 carcinomas, and monosomy 17 was seen in 2 carcinomas. Our findings suggest that such abnormalities are an in vivo phenomenon and may be important in the neoplastic proliferation of thyroid gland. (C) Elsevier B.V., 2000. All rights reserved.

Peripheral position of CCND1 and HER-2/neu oncogenes within chromosome territories in esophageal and gastric cancers non-related to amplification and overexpression

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mapping MHC Genes in River Buffalo

The major histocompatibility complex (MHC) contains a set of genes necessary for antigen presentation in the immune system. This gene dense and polymorphic region of the mammalian genome is of considerable interest due to the role of MHC genes in immune function and animal health. Previous cytogenetic studies have indicated that the MHC in river buffalo resides on the short arm of chromosome 2 (BBU2). A 5000-rad radiation hybrid mapping panel was recently generated to enable construction of a whole genome map of river buffalo. To this and, the aims of this project were to elucidate the general organization of the MHC on BBU2, and to compare gene order within this region to the MHC in cattle. PCR primers were selected from the bovine gene map and used with the BBURH(5000) panel to map a set of ten MHC class 11 genes in river buffalo. Analysis indicates that these genes fall into two linkage groups, consistent with organization of the MHC in cattle. This comparison of buffalo and bovine MHC gene order provides the first insight into the organization of the MHC on river buffalo chromosome 2.

Bi-Lipschitz A-triviality of map germs and Newton filtrations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Finiteness theorem for topological contact equivalence of map germs

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On pairs of regular foliations in R(3) and singularities of map-germs

We study germs of pairs of codimension one regular foliations in R(3) . We show that the discriminant of the pair determines the topological type of the pair. We also consider various classifications of the singularities of the discriminant.

Amphibia, Anura, Hylidae, Dendropsophus melanargyreus (Cope, 1887): distribution extension, new state record and geographic distribution map.

We present the first record of Dendropsophus melanargyreus for the state of São Paulo and a distribution map for this species. This new record represents the southeastern limit of distribution, which is 106 Km from the nearest locality previously recorded for this species and is the fourth new register of anuran to northwestern region of São Paulo in the last two years, increasing species list of the region from 33 to 36 species. This results evidence the importance of this region as priority area for inventory.

Mathematical glimpse on the Y chromosome degeneration

The Y chromosomes are genetically degenerate and do not recombine with their matching partners X. Non-recombination of XY pairs has been pointed out as the key factor for the degeneration of the Y chromosome. The aim here is to show that there is a mathematical asymmetry in sex chromosomes which leads to the degeneration of Y chromosomes even in the absence of XX and XY recombination. A model for sex-chromosome evolution in a stationary regime is proposed. The consequences of their asymmetry are analyzed and lead us to a couple of conclusions. First, Y chromosome degeneration shows up v 2 more often than X chromosome degeneration. Second, if nature prohibits female mortalities from beeing exactly 50%, then Y chromosome degeneration is inevitable.

Degeneration of the Y chromosome in evolutionary aging models

The Y chromosomes are genetically degenerated and do not recombine with their matching partners X. Recombination of XX pairs is pointed out as the key factor for the Y chromosome degeneration. However, there is an additional evolutionary force driving sex-chromosomes evolution. Here we show this mechanism by means of two different evolutionary models, in which sex chromosomes with non-recombining XX and XY pairs of chromosomes is considered. Our results show three curious effects. First, we observed that even when both XX and XY pairs of chromosomes do not recombine, the Y chromosomes still degenerate. Second, the accumulation of mutations on Y chromosomes followed a completely different pattern then those accumulated on X chromosomes. and third, the models may differ with respect to sexual proportion. These findings suggest that a more primeval mechanism rules the evolution of Y chromosomes due exclusively to the sex-chromosomes asymmetry itself, i.e., the fact that Y chromosomes never experience female bodies. Over aeons, natural selection favored X chromosomes spontaneously, even if at the very beginning of evolution, both XX and XY pairs of chromosomes did not recombine.