Influence of ovarian hormones deprivation on gene expression in the lower urinary tract of rats

OBJECTIVE: Identify the influence of ovarian hormone deprivation in expression genes on the lower urinary tract of rats. MATERIALS AND METHODS: This study deals with gene screening on lower urinary tract of rats. Fifty isogenic rats divided in two groups of twenty-five animals have their lower urinary tract surgically removed: group I, ovariectomized rats 30 days prior to surgery; group II, non-ovariectomized rats. Total RNA was isolated from bladder and urethra, and differential expression of genes was analyzed quantitative, qualitative and comparatively by array technology and RT-PCR. RESULTS: A total of 76 candidate genes were identified as differentially expressed between the groups, 26 being lower expressed in group II, and 50 in group I. Among them, differential expression validation was confirmed by RT-PCR for three lower expressed genes in group I: Vascular Endothelial Growth Factor (VEGF), Beta-2 Microglobulin (B2M) and Cytochrome c Oxidase subunit I (COX I). CONCLUSION: Ovarian hormone deprivation influences the expression genes on lower urinary tract. We demonstrated that a 30-day period of castration down regulate the expression of VEGF, B2M and COX I in adult rats which are involved in activities of angiogenesis, immune responses and cellular metabolism respectively.

Associação dos polimorfismos PvuII, XbaI, MspI e HaeII do gene do receptor de estrogênio alfa com a densidade mamográfica em mulheres após menopausa / Estrogen alpha receptor gene polymorphism PVUII, XBAI, MSPI, and HAEIII association with mammographic density in post menopausal women

Genes que codificam proteínas envolvidas na biossíntese, na ação e na metabolização dos esteróides sexuais são polimórficos. Essa condição poderia explicar as variações individuais na densidade mamográfica. Avaliaram-se 115 mulheres pós-menopáusicas não-usuárias de terapia hormonal e sem lesões mamárias clínica ou mamograficamente indentificadas. Todas se submeteram à mamografia bilateral e determinou-se densidade radiológica por três observadores independentes, tomando-se como base a classificação dos padrões mamográficos do ACR-BIRADS®, 2003 (duas avaliações subjetivas e uma computadorizada – ferramenta de histograma de escala de cinza do software Adobe Photoshop® 7.0). Obtiveram-se amostras de raspado bucal para extração de DNA, que foi realizada segundo protocolo do Kit GFX®, da Amersham-Pharmacia, para células bucais. Após a extração do DNA, realizou-se PCR-RFLP (Reação de Cadeia Polimerase – Restriction Fragment Length Polymorphism) para análise dos polimorfismos presentes no íntron (HaeIII e Xbal) e éxon 1 (MspI e PvuII) do gene do Reα. Houve alto grau de concordância entre os três observadores na determinação da densidade mamográfica. Trinta e quatro mulheres tinham mamas densas e 81, mamas lipossubstituídas. Não houve associação significativa entre os polimorfismos HaeIII e PvuII com a densidade mamográfica. Porém, essa mesma relação com os polimorfismos MspI e XbaI revelou tendência ao significado estatístico.

Genes that encode proteins involved in the biosynthesis, action and metabolism of sexual steroids are polymorphics. This condition could explain the individual variations in mammographic density. A hundred and fifteen postmenopausal women, notin use of hormonal therapy and without clinical or mammographic lesions were assessed.Three independent observers classified mammography density pattern considering the ACR-BIRADS®2003(two subjective assessments and one objective assessment - software Adobe Photoshop 7.0). Oral swabs (Cytobrush) were obtained to extract DNA, following the Kit GFX ® from Amersham-Pharmacia protocol to oral cells. After DNA extraction, PCR-RFLP (Polymerase Chain Reaction - Restriction Fragment Length Polymorphism) was performed to analyze the presence of polymorphisms in intron 1 (HaeIII and Xbal) and exon 1 (MspI and PvuII) from estrogen receptor gene. There was a good agreement among the tree observers with regard to mammographic density. Thirty four women had dense breasts and eighty one had non dense breast. Estrogen receptor gene polymorphisms HaeIII and PvuII showed no association with mammographic density, while this association between estrogen receptor gene polymorphisms Mspl and Xbal showed near the significance.

Identification and complete sequencing of novel human transcripts through the use of mouse orthologs and testis cDNA sequences

The correct identification of all human genes, and their derived transcripts, has not yet been achieved, and it remains one of the major aims of the worldwide genomics community. Computational programs suggest the existence of 30,000 to 40,000 human genes. However, definitive gene identification can only be achieved by experimental approaches. We used two distinct methodologies, one based on the alignment of mouse orthologous sequences to the human genome, and another based on the construction of a high-quality human testis cDNA library, in an attempt to identify new human transcripts within the human genome sequence. We generated 47 complete human transcript sequences, comprising 27 unannotated and 20 annotated sequences. Eight of these transcripts are variants of previously known genes. These transcripts were characterized according to size, number of exons, and chromosomal localization, and a search for protein domains was undertaken based on their putative open reading frames. In silico expression analysis suggests that some of these transcripts are expressed at low levels and in a restricted set of tissues.

O espectro das falências ovarianas ligadas ao cromossomo X / Ovarian failure spectrum related to X chromosome

A falência ovariana manifesta-se clinicamente por amenorréia primária ou secundária, e do ponto de vista hormonal caracteriza-se pelos níveis elevados de gonadotrofinas hipofisàrias, principalmente FSH, cuja etiologia pode ser atribuída a varias causas, como reduçäo numérica ou rearranjos do cromossomo X, entre outras. Além da síndrome de Turner (monossomia do cromossomo X, com ou sem mosaicismo cromossômico), cujo principal estigma - a baixa estatura - e o infantilismo sexual apontam o diagnóstico, rearranjos do braço longo de X (Xq), ou mutaçöes instaladas em genes mapeados neste cromossomo estäo relacionados com a falência ovariana em meninas pré-púberes e em mulheres adultas jovens, sem outros sinais clínicos. Neste cromossomo, nos segmentos da falência ovariana precoce (FOP1 e FOP2) situam-se genes já relacionados à insuficiência ovariana de instalaçäo precoce. Esta revisäo trata destas alteraçöes, algumas detectadas pelas técnicas citogenéticas convencionais, outras somente por meio de recursos de biologia molecular.

Molecular biology and gynecology: CD 36 and its interactions with tamoxifen

Tamoxifen (TAM) is an antiestrogenic drug widely used in breast cancer treatment. By using the Differential Display technique in normal and malignant breast tissues, before and during TAM therapy, we were able to demonstrate that expression of the CD36 gene is down-regulated by this drug. CD36 is a cell-surface glycoprotein that acts as a receptor for thrombospondin-1, oxidized-LDL and collagens type I and IV. Thrombospondin-1 is involved in invasion, metastasis and angiogenesis and therefore the down-regulation of CD36 induced by TAM, might correspond to an alternative mechanism of action of this drug. CD36 is also one of the receptors for the oxidized-LDL which in turn is involved in pathogenesis of arteriosclerosis; thus the down-regulation of CD36 during TAM might explain the at least in part the lower levels of myocardial infarction during its use.