Search PubMed⌕ Search

Biomedical subjects

E Costa

Publications and source records attributed to E Costa.

At least 19 recordsLinked to original sources
PubMed2006

The benzamide MS-275 is a potent, long-lasting brain region-selective inhibitor of histone deacetylases.

The association of the histone deacetylase (HDAC) inhibitor valproate (VPA) with atypical antipsychotics has become a frequent treatment strategy for schizophrenia and bipolar disorder. Because the VPA doses administered are elevated, one cannot assume that the benefits of the VPA plus antipsychotic treatment are exclusively related to the covalent modifications of nucleosomal histone tails. We compared the actions of N-(2-aminophenyl)-4-[N-(pyridin-3-yl-methoxycarbonyl)aminomethyl]benzamide derivative (MS-275), which is a potent HDAC inhibitor in vitro, with the actions of VPA for their ability to (i) increase the acetylated status of brain nucleosomal histone tail domains and (ii) to regulate brain histone-RELN and histone-GAD(67) promoter interactions. MS-275 increases the content of acetylhistone 3 (Ac-H3) in the frontal cortex. Whereas this response peaks after a s.c. injection of 15 micromol/kg, the increase in Ac-H3 content in the hippocampus becomes significant only after an injection of 60 micromol/kg, suggesting that MS-275 is 30- to 100-fold more potent than VPA in increasing Ac-H3 in these brain regions. In contrast to VPA, MS-275, in doses up to 120 micromol/kg, fails to increase Ac-H3 content in the striatum. Chromatin immunoprecipitation shows that MS-275 increases Ac-H3-RELN and Ac-H3-GAD(67) promoter interaction in the frontal cortex. These results suggest that MS-275 is a potent brain region-selective HDAC inhibitor. It is likely that, in addition to MS-275, other benzamide derivatives, such as sulpiride, are brain-region selective inhibitors of HDACs. Hence, some benzamide derivatives may express a greater efficacy than VPA as an adjunctive to antipsychotics in the treatment of epigenetically induced psychiatric disorders.

Animals↗
PubMed2006

Tumour banks in pediatric oncology.

INTRODUCTION: The information offered by the new genomic and proteomic techniques will play a central role in our knowledge of cancer; but it is limited by the lack of available tissue samples. Cancer in children is a sum of infrequent diseases, so tumor banks are support tools for translational research, providing access to a sufficiently large series of samples, which would minimize the asymmetric effect of the diverse origin. MATERIAL AND METHODS: From 2003 a Molecular Pathology Network in Pediatric Solid Tumors Netwoks exists in Spain, and we are a part of it. Our aim was to create a pediatric tumor bank program and consensus documents about its use. RESULTS: Standard Operating Procedures for collection and transport of samples have been created. CONCLUSIONS: Thinking about the fast progress in Molecular Biology and the low frequency in pediatric tumors, it is vital to consider the importance of a bio bank.

Adolescent↗
PubMed2005

Reelin and glutamic acid decarboxylase67 promoter remodeling in an epigenetic methionine-induced mouse model of schizophrenia.

Reduction of prefrontal cortex glutamic acid decarboxylase (GAD67) and reelin (mRNAs and proteins) expression is the most consistent finding reported by several studies of postmortem schizophrenia (SZ) brains. Converging evidence suggests that the reduced GAD67 and reelin expression in cortical GABAergic interneurons of SZ brains is the consequence of an epigenetic hypermethylation of RELN and GAD67 promoters very likely mediated by the overexpression of DNA methyltransferase 1 in cortical GABAergic interneurons. Studies of the molecular mechanisms (DNA methylation plus related chromatin remodeling factors) that cause the down-regulation of reelin and GAD67 in SZ brains have important implications not only to understand the disease pathogenesis but also to improve present pharmacological interventions to treat SZ. The mouse treated with l-methionine models some of the molecular neuropathologies detected in SZ, including the hypermethylation of RELN promoter CpG islands and the down-regulation of reelin and GAD67 expression. We now report that in these mice, RELN and GAD67 promoters express an increased recruitment of methyl-CpG binding domain proteins. In these mice the histone deacetylase inhibitor valproate, which increases acetylated histone content in cortical GABAergic interneurons, also prevents MET-induced RELN promoter hypermethylation and reduces the methyl-CpG binding domain protein binding to RELN and GAD67 promoters. These findings suggest that DNA hypermethylation and the associated chromatin remodeling may be critically important in mediating the epigenetic down-regulation of reelin and GAD67 expression detected in cortical GABAergic interneurons of SZ patients.

Animals↗
PubMed2005

Erythropoietin levels in the different clinical forms of hereditary spherocytosis.

Erythropoietin (EPO), the main growth factor responsible for the regulation of red blood cell production, may be overproduced when blood loss or haemolysis occurs. Patients with mild hereditary spherocytosis (HS) are able to maintain normal haemoglobin concentration, whereas typical and severe HS patients develop an anaemic state. Splenectomy usually reverses anaemia. We aimed to clarify the role of EPO in the response to enhanced spherocyte destruction, and to look for a linkage with the broad clinical spectra of HS. EPO levels, reticulocyte count and production index (RPI), other parameters used to classify HS and the protein deficiencies underlying HS were evaluated in previously diagnosed unsplenectomised (n = 24) and splenectomised (n = 10) patients presenting mild, typical or severe HS. A significant increase in EPO was observed in all unsplenectomised HS patients. In the mild form, a significant correlation of EPO with reticulocyte count and RPI was observed; however, this correlation disappeared in typical HS patients. Splenectomised HS patients presented a correction in EPO levels in all forms of HS, although the reticulocyte count and RPI sustained slightly higher values. Our data show HS as a disease linked to an overproduction of EPO, according to the severity of the disease; however, a disturbance in erythropoiesis seems to occur in typical HS. Moreover, splenectomy leads to a correction in the EPO levels.

Adult↗
PubMed2005

Protein deficiency balance as a predictor of clinical outcome in hereditary spherocytosis.

Vertical and horizontal interactions between membrane constituents account for integrity, strength and deformability of the erythrocyte. Disruption of vertical interactions caused by membrane protein deficiencies in hereditary spherocytosis (HS), favor membrane vesiculation with development of spherocytic cells. Our aim was to evaluate the hematological and clinical presentation of HS according to the type and amount of protein deficiency. We studied 81 Portuguese individuals, 71 belonging to 21 families plus 10 unrelated subjects, and found that 51 of them were HS patients. Patients were classified as presenting mild, typical or severe HS, according to laboratory results and clinical follow-up. We performed screening tests and the standardized electrophoretic membrane protein analysis to identify and quantify protein deficiencies. We found band 3 and ankyrin deficiencies as the major causes for HS. The ratios between the value of the primary and/or secondary protein deficiencies showed significantly different values according to the severity of HS, and a significant inverse correlation with the severity of HS was observed. In mild HS, the ratios between protein deficiencies reflected equivalent protein deficiencies, while an unbalance was observed in typical HS, which was enhanced in severe HS. Our data suggest that the relative quantification of each major membrane protein and of the ratios between the values of protein deficiencies may be helpful in providing additional data about the clinical outcome of HS.

Anion Exchange Protein 1, Erythrocyte↗
PubMed2005

Effectiveness and persistence of a topical treatment for cervical ectropion with deoxyribonucleic acid.

AIM: The aim of this study was to estimate short and long term effectiveness of a topical treatment for cervical ectropion with 5 mg of deoxyribonucleic acid (DRNA). METHODS: A randomized case-control study was carried out. Two-hundred and twenty patients, colposcopically diagnosed with cervical ectropion, were consecutively enrolled and randomly divided into 2 groups: treated (group 1) and controls (group 2). The therapeutic plan consisted of DRNA 5 mg vaginal suppositories, administered for 15 days monthly; subsequently posology was reduced gradually. Both groups underwent a clinical and colposcopical follow-up on the 1st, 4th, 10th and 22nd months after the first examination. At the end of the study, the size of ectropion was considered a parameter of re-epithelialization and provided a criterion of treatment effectiveness. According to this protocol, subjects were defined improved, stable or worsened. Statistical analysis including Pearson chi2 tests, Fisher's exact tests, Yate's corrected chi2 and relative-risk (95% CI) was performed. RESULTS: Of the 220 enrolled patients, 140 completed the study protocol: 76 treated and 64 controls. Outcomes after treatment and follow-up consisted of: 74 (97.4%) improved in group 1, against 2 cases (3.1%) in group 2. High statistical significance was reported comparing outcome frequencies in the 2 groups (P<0.0001). CONCLUSIONS: This study shows a significant reduction (P<0.0001) in cervical ectropion size between cases (topical treatment with DRNA 5 mg) and controls. A follow-up of 22 months confirmed the persistence and effectiveness of this medical approach.

Adult↗
PubMed2004

Enhanced dizocilpine efficacy in heterozygous reeler mice relates to GABA turnover downregulation.

Reelin synthesized by cortical GABAergic interneurons throughout the telencephalon is secreted into the extracellular matrix (ECM) and binds with nM affinity to integrin receptors located at dendritic spine postsynaptic densities and positively modulates Arc and other dendritic resident mRNAs translation, thereby facilitating the onset of synaptic plasticity and LTP consolidation. Accordingly, the reelin haploinsufficient heterozygous reeler mice (HRM) express a marked decrease of cortical thickness, of cortical and hippocampal dendritic spine density, and of cortical GAD67 expression. Behaviorally, HRM manifest a sensorimotor deficit, an exaggerated response to fear, and a deficit in olfactory discrimination learning. HRM and wild-type mice (WTM) were trained to retrieve to criterion palatable chocolate-flavored food pellets in an eight-arm radial maze. In 9-14 days of training HRM and WTM learned the task equally well committing only a few errors. However, HRM, when compared with WTM, show a greater cognitive impairment following the administration of dizocilpine. Also, HRM are more susceptible to the increased locomotion and stereotypic behavior elicited by dizolcipine. The enhanced dizocilpine susceptibility of HRM is not due to differences in pharmacokinetics because the levels of dizocilpine in cortices of HRM and WTM were virtually equal. We also failed to detect differences between HRM and WTM in glutamate brain content and in the rate of 13C-glucose incorporation into the glutamate brain pools. In contrast we found that the conversion index of glutamate into GABA (an indirect measurement of GABA turnover rate) is decreased in cortex, hippocampus and striatum of HRM when compared to WTM. Thus, HRM recapitulate several neurochemical and behavioral endophenotypes reminiscent of schizophrenia and these mice can be proposed as a relevant animal model for the study of pharmacological treatments aimed at alleviating the sensory-motor and cognitive dysregulation associated with schizophrenia.

Animals↗
PubMed2004

Coexistence of congenital red cell pyruvate kinase and band 3 deficiency.

The authors report the case of a 9-year-old Caucasian girl, born in northern Portugal, with chronic nonspherocytic haemolytic anaemia and without family history of anaemia. The aethiological study of this anaemia revealed pyruvate kinase deficiency (PKD), because of two previously described mutations (426Arg-->Trp and 510Arg-->Gln). Since the blood smear revealed features not fully compatible with PKD diagnosis, additional tests were performed for the propositus and her parents, namely red blood cell membrane protein analysis. A decrease in proteins band 3 (15%) and 4.2 (18%) was found in the propositus. Her father presented only a decrease in band 3 (11%). Coexistence of PKD and erythrocyte membrane proteins deficiency in the same patient is very uncommon. Our findings suggest that a careful blood smear observation may lead to the identification of a combined deficiency in erythrocyte membrane proteins and enzymopathies.

Anemia, Hemolytic, Congenital↗
PubMed2004

Determination of neutrophil Fcgamma receptor IIIb antigens (HNA-1a, HNA-1b and HNA-1c) by fluorescence-primed allele-specific polymerase chain reaction.

We evaluate a technique for genotyping HNA-1a, -1b and -1c antigens, resorting to fluorescence-primed allele-specific polymerase chain reaction (FPAS-PCR), and determine the frequency of the different genotypes in a normal Portuguese population. Our results indicate that the FPAS-PCR system is a reliable and simple tool for genotyping the neutrophil Fcgamma receptor IIIB antigens. The HNA-1a, -1b and -1c gene frequencies of 42.98, 84.21 and 6.14%, respectively, found in this study are similar to those reported for other white populations.

Alleles↗
PubMed2004

Familial suicide behaviour: association with probands suicide attempt characteristics and 5-HTTLPR polymorphism.

OBJECTIVE: There is compelling evidence that a serotonergic dysfunction may play a major role in suicide behaviour and it has also been demonstrated that suicide is, at least partially, genetically determined. Thus, the serotonin-related genes are the major candidates. Previously a functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) was identified and the presence of the short allele (S) was found to be associated with a lower level of expression of the gene and lower levels of 5-HT uptake when compared with the long allele (L). The purpose of this study was to evaluate the association between family suicide behaviour history and probands' suicide attempt (SA) history, SA characteristics and 5-HTTLPR genotype. METHOD: We genotyped 237 probands (major depressed or schizophrenic patients) and used a semistructured interview to determine probands' SA characteristics and first- and second-degree family suicidal behaviour. RESULTS: An association between suicidal family history and proband's SA but not with SA characteristics and probands genotype was found. CONCLUSION: Our results suggest that multiple biological and environmental factors underlie familial transmission of suicidal behaviour.

Behavior↗
PubMed2004

A GABAergic cortical deficit dominates schizophrenia pathophysiology.

Several lines of evidence support the role of an epigenetic-induced GABAergic cortical dysfunction in schizophrenia psychopathology, which is probably dependent on an increase in the expression of DNA-methyltransferase-1 occurring selectively in GABAergic neurons. The key enzyme regulating GABA synthesis, termed glutamic acid decarboxylase 67 (GAD67) and the important neurodevelopmental protein called reelin are coexpressed in GABAergic neurons. Upon release, GABA and reelin bind to postsynaptic receptors located in dendrites, somata, or the axon initial segment of pyramidal neurons. Because GAD67 and reelin are downregulated in schizophrenia, it is suggested that schizophrenics may express GABAergic deficit-related alterations of pyramidal neuron function. A reduction of dendritic spines is a finding reported in the prefrontal cortex of schizophrenia patients. Because dendritic spines are innervated by glutamatergic axon terminals, very probably this reduction of dendritic spine expression is translated into a functional deficit of glutamatergic transmission. Plastic modifications of neuronal circuits are probably dependent on GABAergic transmitter tone, and it is likely that GABAergic dysfunction is at the root of synaptic plasticity deficits in schizophrenia. Thus, a possible avenue for the treatment of schizophrenia would be to address this GABAergic functional deficit using positive allosteric modulators of the action of GABA at GABAA receptors. Benzodiazepines (BZ) such as diazepam are effective in treating positive and negative symptoms of schizophrenia, but because they positively modulate GABAA receptors expressing alpha1 subunits, these BZs cause sedation and tolerance. In contrast, imidazenil, a full allosteric modulator of GABAA receptors expressing alpha5 subunits may reduce psychotic symptomatology without producing sedation. Hence, imidazenil should be appropriately studied as a prospective candidate for a pharmacological intervention in schizophrenia.

Animals↗
PubMed2003

DNA-methyltransferase 1 mRNA is selectively overexpressed in telencephalic GABAergic interneurons of schizophrenia brains.

A down-regulation of reelin and glutamic acid decarboxylase (GAD) 67 mRNAs was detected in gamma-aminobutyric acid (GABA)ergic cortical interneurons of schizophrenia (SZ) postmortem brains (10), suggesting that the availability of GABA and reelin may be decreased in SZ cortex. In situ hybridization of the mRNA encoding for DNA-methyltransferase 1, which catalyzes the methylation of promoter CpG islands, shows that the expression of this mRNA is increased in cortical GABAergic interneurons but not in pyramidal neurons of SZ brains. Counts of reelin mRNA-positive neurons in Brodmann's area 10 of either nonpsychiatric subjects or SZ patients show that the expression of reelin mRNA is decreased in layer-I, -II, and -IV GABAergic interneurons of SZ patients. These findings are consistent with the hypothesis that the increase of DNA-methyltransferase 1 expression in telencephalic GABAergic interneurons of SZ patients causes a promoter hypermethylation of reelin and GAD(67) and perhaps of other genes expressed in these interneurons. It is difficult to decide whether this dysfunction of GABAergic neurons detected in SZ is responsible for this disease or is a consequence of this disorder. Although at present we cannot differentiate between these two alternatives, it is important to consider that so far a molecular pathology of cortical GABAergic neurons appears to be the most consistent finding associated with SZ morbidity.

Adult↗
PubMed2003

On the putative physiological role of allopregnanolone on GABA(A) receptor function.

To obtain definitive evidence for a physiological allosteric modulatory role for endogenous brain ALLO on GABA(A) receptor function, we studied GABA(A) receptor activity under conditions in which the concentration of endogenous brain ALLO was decreased by about 80% for longer than 5 h following the administration of SKF 105111- 17beta-17-[bis (1methylethyl) amino carbonyl] androstane-3,5-diene-3-carboxylic acid (SKF), a potent inhibitor of 5alpha-reductases Type I and II. We used the in situ patch-clamp technique to record GABA-evoked currents and spontaneous inhibitory postsynaptic currents (sIPSCs) from pyramidal neurons in neocortical slices of vehicle- or SKF-treated mice. The potency, but not the efficacy, of exogenously applied GABA was decreased in slices from mice treated with SKF. When neocortical slices were treated in vitro for 3 h with 10 microM SKF, ALLO was also reduced (25-30%) and in addition, the GABA dose-response curve was shifted to the right; however this shift was not as marked as the shift in the slices obtained from mice treated with SKF, in keeping with the smaller decrease of the ALLO content in these slices. Furthermore, direct application of ALLO to these slices shifted the dose-response curve of GABA back toward a non-SKF treated profile. We then analyzed GABAergic sIPSCs in neocortical slices obtained from vehicle or SKF-treated mice. Mean decay time and charge transfer were significantly reduced by SKF treatment. The decay of sIPSCs was best fitted by two exponentials, but only the fast component was decreased in the SKF group. Direct application of ALLO (100 nM) normalizes the sIPSC kinetics in slices from ALLO depleted mice. No changes were detected in the amplitude or frequency of sIPSCs. These data demonstrate that endogenous ALLO physiologically regulates spontaneously induced Cl(-) current by acting on a specific recognition site, which is probably located on GABA(A) receptors (a receptor on a receptor), thereby prolonging inhibitory currents by facilitating conformational transition of the GABA-gated Cl(-) channel to an open state.

5-alpha Reductase Inhibitors↗
PubMed2002

An epigenetic mouse model for molecular and behavioral neuropathologies related to schizophrenia vulnerability.

Reelin and glutamic acid decarboxylase (GAD)67 expressed by cortical gamma-aminobutyric acid-ergic interneurons are down-regulated in schizophrenia. Because epidemiological studies of schizophrenia fail to support candidate gene haploinsufficiency of Mendelian origin, we hypothesize that epigenetic mechanisms (i.e., cytosine hypermethylation of CpG islands present in the promoter of these genes) may be responsible for this down-regulation. Protracted l-methionine (6.6 mmolkg for 15 days, twice a day) treatment in mice elicited in brain an increase of S-adenosyl-homocysteine, the processing product of the methyl donor S-adenosyl-methionine, and a marked decrease of reelin and GAD67 mRNAs in both WT and heterozygous reeler mice. This effect of l-methionine was associated with an increase in the number of methylated cytosines in the CpG island of the reelin promoter region. This effect was not observed for GAD65 or neuronal-specific enolase and was not replicated by glycine doses 2-fold greater than those of l-methionine. Prepulse inhibition of startle declined at a faster rate as the prepulsestartle interval increased in mice receiving l-methionine. Valproic acid (2 mmolkg for 15 days, twice a day) reverted l-methionine-induced down-regulation of reelin and GAD67 in both WT and heterozygous reeler mice, suggesting an epigenetic action through the inhibition of histone deacetylases. The same dose of valproate increased acetylation of histone H3 in mouse brain nearly 4-fold. This epigenetic mouse model may be useful in evaluating drug efficacy on schizophrenia vulnerability. Hence the inhibition of histone deacetylases could represent a pharmacological intervention mitigating epigenetically induced vulnerability to schizophrenia in individuals at risk.

Acetylation↗
PubMed2002

Reelin function in neural stem cell biology.

In the adult brain, neural stem cells (NSC) must migrate to express their neuroplastic potential. The addition of recombinant reelin to human NSC (HNSC) cultures facilitates neuronal retraction in the neurospheroid. Because we detected reelin, alpha3-integrin receptor subunits, and disabled-1 immunoreactivity in HNSC cultures, it is possible that integrin-mediated reelin signal transduction is operative in these cultures. To investigate whether reelin is important in the regulation of NSC migration, we injected HNSCs into the lateral ventricle of null reeler and wild-type mice. Four weeks after transplantation, we detected symmetrical migration and extensive neuronal and glial differentiation of transplanted HNSCs in wild-type, but not in reeler mice. In reeler mice, most of the injected HNSCs failed to migrate or to display the typical differentiation pattern. However, a subpopulation of transplanted HNSCs expressing reelin did show a pattern of chain migration in the reeler mouse cortex. We also analyzed the endogenous NSC population in the reeler mouse using bromodeoxyuridine injections. In reeler mice, the endogenous NSC population in the hippocampus and olfactory bulb was significantly reduced compared with wild-type mice; in contrast, endogenous NSCs expressed in the subventricular zonewere preserved. Hence, it seems likely that the lack of endogenous reelin may have disrupted the migration of the NSCs that had proliferated in the SVZ. We suggest that a possible inhibition of NSC migration in psychiatric patients with a reelin deficit may be a potential problem in successful NSC transplantation in these patients.

Animals↗