Biomedical subjects

J Fernandez-Piqueras

Publications and source records attributed to J Fernandez-Piqueras.

5 recordsLinked to original sources

PubMed2000

Pathological gambling and DNA polymorphic markers at MAO-A and MAO-B genes.

This study was conducted to detect a possible association of MAOA and/or MAOB genes with pathological gambling (PG). DNA polymorphisms in MAOA and MAOB genes were screened by molecular analysis in 68 individuals (47 males and 21 females) meeting ICD-10 and DSM-IV criteria for pathological gambling and 68 healthy comparison controls matched for age and sex. There were no significant differences between pathological gamblers and healthy volunteers in overall allele distribution at the MAOA gene polymorphism. However there was a significant association between allele distribution and the subgroup of severe male gamblers (n = 31) compared to the males in the group of healthy volunteers (chi2 = 5246; df = 1; P < 0.05 [Bonferroni corrected]). No association was found between the MAOB polymorphic marker and PG. Allele variants at the MAOA, but not the MAOB gene may be a genetic liability factor in PG, at least in severe male gamblers. Molecular Psychiatry(2000) 5, 105-109.

Adult↗

PubMed1997

Hypermethylation of a 5' CpG island of p16 is a frequent event in non-Hodgkin's lymphoma.

Hypermethylation of a 5' CpG island of p16 gene has been recently described as a possible way of inactivation of this tumor suppressor gene, alternative to deletions and mutations. We have investigated if hypermethylation of a 5' CpG island of p16 occurs in non-Hodgkin's lymphoma (NHL) and normal lymphoid tissue. A total of 82 NHLs were examined for p16 methylation by Southern blot and PCR analysis. Hypermethylation was detected in approximately 20% of B cell lymphomas of both low and high grade and in 15% of T cell NHL. The highest rate of p16 gene methylation in tumors was found among MALT (mucosa-associated lymphoid tissue) lymphomas in which the percentage of cases with p16 gene methylation reached 67%. However, normal lymphoid tissue was always unmethylated at p16 locus. These results indicate that p16 gene methylation is a frequent event in NHLs, mainly in MALT lymphomas, and suggest that it could be an important mechanism of inactivation of this gene.

Binding Sites↗

PubMed1993

Non-uniform distribution of methylatable CCGG sequences on human chromosomes as shown by in situ methylation.

We carried out in situ methylation of human chromosomes with the HpaII methylase using [3H]methyl-S-adenosyl-L-methionine as the methyl group carrier. Autoradiographs localising [3H]methyl groups show methylatable CCGG sequences in the R-bands as well as in the short arms of the acrocentric chromosomes that include ribosomal DNA. The strongest labelling was observed over a subset of R-bands, including T-bands. Since methylatable CCGG sequences are representative of the unmethylated fraction of DNA, we suggest that differences in the degree of DNA methylation could be involved in the structure and function of chromosomal bands.

Base Sequence↗

PubMed1984

An acidic silver staining method for synaptonemal complexes under light microscopy.

A simple method is presented by which synaptonemal complexes (SCs) can be visualized under bright field microscopy. Staining was accomplished with a silver nitrate solution adjusted to pH 3-3.5 with formic acid, after an acidic fixation. This method is suitable for the demonstration of SCs, centromeres and NOR regions in both mammalian (Rattus norvegicus, 'Wistar') and orthopteran spermatocytes (Steropleurus martorelli complex). Results suggest that pretreatment with solutions of alkaline pH are not needed for demonstrating SCs, and that the silver impregnation may also operate when the proteinaceous lateral elements of the SC are subjected to low pH conditions. Differential staining of the X chromosome during meiosis in Orthoptera, and a core-like structure in the chromosomes during the more condensed stages of meiosis and mitosis can also be shown.

Animals↗

PubMed1982

Differential staining of the X-chromosome during meiosis of orthoptera by a silver impregnation procedure.

Differential staining of the X chromosome of Orthoptera, which normally cannot be distinguished from the autosomes during the more condensed stages of meiosis, has been achieved by a silver impregnation procedure involving a pretreatment with 2 x SSC at 60 degrees C. The results suggest that the saline citrate solution preferentially extracts proteins from the X chromosome. This method may be useful for distinguishing chromosome regions composed of facultative heterochromatin in Orthoptera.

Animals↗