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Biomedical subjects

I Arrieta

Publications and source records attributed to I Arrieta.

31 records · Page 2Linked to original sources
PubMed1998

Galectin-3 down-regulates IL-5 gene expression on different cell types.

Galectin-3 is an animal lectin, formerly named epsilon-binding protein or Mac-2, which has been described to play an important role in some inflammatory processes by the implication of different cells and the increase in cell adhesion functions through laminin binding activity. In this work we analyzed the role of galectin-3 in the modulation of Th2 cytokines that have an important role in the development of the inflammatory response. We have found that the addition of galectin-3 to human eosinophils, the eosinophilic cell line EoL-3, PBMC, and an Ag-specific T cell line (CD4+) produced a selective inhibition of IL-5 transcription. No inhibitory effect was found on the IL-4 mRNA transcription rate. The inhibitory effect on IL-5 transcription was reversed by incubation with lactose and using specific Ab against galectin-3. Galectin-3 is able to induce inhibition of the IL-5 released in the supernatants from PBMC stimulated with phorbol 12,13-dibutyrate and anti-CD3. Similar results were obtained when a T-specific cell line was stimulated with Ag. Also, EoL-3 stimulated with anti-CD32 produced IL-5 protein, the synthesis of which was partially inhibited by galectin-3. The present results demonstrate that galectin-3 induces a selective down-regulation of IL-5 expression in different cell types, opening important new possibilities in the regulation of the allergic reactions.

Antigens, Differentiation↗
PubMed1998

The protein phosphatase inhibitor okadaic acid induces heat shock protein expression and neurodegeneration in rat hippocampus in vivo.

The tumor promoter okadaic acid is a potent and specific inhibitor of protein phosphatases 1 and 2A and therefore it is a useful tool for studying the participation of protein phosphorylation in cellular processes. Since it has been shown that in cultured neurons OKA behaves as a potent neurotoxin, in the present work we have administered different doses of this compound into the dorsal rat hippocampus, in order to assess its neurotoxicity in vivo. Cresyl violet staining of hippocampal sections revealed that as early as 3 h after injection of 300 ng OKA a notable neurodegeneration occurred in the CA1 subfield, the dentate gyrus, and the hilus, particularly in the former. Neuronal death was more evident at 24 h and at this time the extent of damage was dose-dependent. The process of neuronal death was accompanied by a loss of the microtubule-associated protein MAP2, as assessed by immunocytochemistry. Moreover, OKA treatment resulted in a notable expression of the inducible heat shock protein 72 in the surviving neurons of the injected hippocampus and in the corresponding CA1 and hilus of the apparently normal contralateral hippocampus. The expression of the heat shock protein was partially prevented in the injected hippocampus and completely blocked in the contralateral CA1 region, by the systemic previous administration of the NMDA receptor antagonist MK-801. These results suggest that protein hyperphosphorylation due to inhibition of phosphatases in vivo induces neuronal stress and subsequent neurodegeneration.

Animals↗
PubMed1998

Olive pollen allergy: searching for immunodominant T-cell epitopes on the Ole e 1 molecule.

BACKGROUND: The amino-acid and nucleotide sequence of Ole e 1 (the major antigen of olive pollen) has been described and the IgE antibody response to this major allergen was associated with DR7/DQ2 antigens. With this previous data we try to define the T-cell epitopes implicated in Ole e 1 reactivity. OBJECTIVES: To study the recognition of T cells (derived from allergic and non-allergic Ole e 1 patients) to Ole e 1 synthetic peptides in order to define immunodominant T-cell epitopes. METHODS: We have compared the proliferative response of the peripheral blood mononuclear cells from Ole e 1 sensitized patients vs. non-sensitized controls, induced by 14 Ole e 1 synthetic peptides. Thirty subjects were classified in two groups: group 1 (non-responders against Ole e 1, n=16) and group 2 (Ole e 1 responders, n=14), according to their clinical parameters and the presence or not in their sera of the significant Ole e 1 IgE antibody levels. RESULTS: Our results shown that it is possible to find T cells reactive to Ole e 1 peptides in patients with and without significant levels of Ole e 1 IgE antibodies. However, the percentage of response was higher in patients with IgE antibodies 71.4% vs 25%), and the recognition profile was different: the control group showed a broad reactivity pattern, in contrast, the response by the 'Ole e 1 responders' group was mainly directed against three peptides of the carboxi-terminal region, peptides 10 (91-102), 12 (109-120) and 13 (119-130), with a response frequency of 35.7, 28.5 and 28.5%, respectively. By direct and inhibition test no antibody response was found against the synthetic peptides. CONCLUSIONS: Our data suggest that the regions between 91 and 102 and 109-130 aminoacids on the Ole e 1 molecule are immunodominant T-cell epitopes. These epitopes are not recognized by IgE antibodies.

Adolescent↗
PubMed1997

Neuronal damage and MAP2 changes induced by the glutamate transport inhibitor dihydrokainate and by kainate in rat hippocampus in vivo.

Neurotoxicity mediated by glutamate is thought to play a role in neurodegenerative disorders, and alterations in cytoskeletal proteins are possibly involved in the mechanisms of neuronal death occurring in Alzheimer's disease. In the present work we studied the neurotoxic effects of the intrahippocampal injections of the glutamate transport inhibitor dihydrokainate as compared to those of kainate, as well as the concomitant changes in the microtubule-associated protein MAP2. Neuronal alterations were assessed at 3, 12, 24, and 48 h by Nissl staining and immunocytochemistry of MAP2. At 3 h, both compounds induced neuronal damage that was correlated with loss of dendritic MAP2 immunoreactivity. Neuronal damage was more evident at 12 h and 24 h after drug injection, and at these times an accumulation of MAP2 in the somata of pyramidal neurons was observed. The effects of dihydrokainate were restricted to the CA1 region and totally prevented by the N-methyl-D-aspartate receptor antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801), but not by the non-NMDA receptor antagonist 2,3-dihydro-6-nitro-7-sulphamoyl-benzo(f)-quinoxaline (NBQX). In contrast, kainate-induced alterations included CA1, CA3, and CA4 subfields, and the changes in CA1 were prevented by NBQX, while MK-801 was ineffective. These results suggest that early MAP2 disruption may be a marker of the excitotoxicity due to activation of different glutamate receptors located in discrete hippocampal regions.

Animals↗
PubMed1997

Angelman syndrome caused by loss of a marker chromosome: cytogenetic and fluorescence in situ hybridization analysis.

We report a cytogenetic and fluorescence in situ hybridization study of a family in which a female child showed all the main characteristics of Angelman syndrome. Her karyotype revealed a translocation between chromosomes 5 and 15 with a partial deletion from 15pter to the Angelman region. Several members of her family appeared to be carriers of the same translocation, but showed no symptoms. The karyotypes showed a marker chromosome, that was not present in the female with Angelman syndrome. Fluorescence in situ hybridization revealed that the marker chromosome corresponded to material from chromosome 15. The present study is in agreement with the suggestion that genomic imprinting is one of the mechanisms involved in Angelman syndrome.

Angelman Syndrome↗
PubMed1996

Autosomal folate sensitive fragile sites in an autistic Basque sample.

The autosomal folate-sensitive fragile sites (FS) expression has been analyzed in an autistic children sample and in a control sample. The results obtained have proved that there is a higher frequency of expression of fragile sites in autistic children than in the control sample. The differences are statistically significant. The sex differences level is similar in both groups in relation to fragile sites expression. Three rare fragile sites, 2q13, 6p23, 12q13, are only expressed in autistic individuals. The meaning of these results have been discussed.

Adolescent↗
PubMed1995

beta-Amyloid peptide fragment 25-35 potentiates the calcium-dependent release of excitatory amino acids from depolarized hippocampal slices.

beta-Amyloid protein (beta AP) has been frequently associated with the neuropathology of Alzheimer's disease (AD), although the mechanisms by which it can induce neurodegeneration are still unknown. Some studies in hippocampal cultured neurons suggest that beta AP, particularly its fragment 25-35, may induce neural growth or render neurons more vulnerable to excitotoxic insults by a mechanism involving intracellular Ca2+ dyshomeostasis. We have studied the effect of fragment 25-35 on the release of endogenous amino acids from hippocampal slices of young adult (3-3.5-month-old) and aged (23-25-month-old) rats, under basal, K(+)-depolarization, and post-depolarization conditions, in the presence and absence of Ca2+. In both young and aged tissue, the basal release of amino acids was not affected by the peptide. By contrast, 1-hr preincubation of slices from young animals with 10 microM 25-35 fragment resulted in a 140% increase of glutamate and aspartate release stimulated by K+ depolarization, compared with the control-stimulated release. These effects were strictly dependent on external Ca2+. Neither the K(+)-stimulated release of gamma-amino butyric acid (GABA) nor the release of glycine, glutamine, taurine, or alanine, which was not stimulated by high K+, were affected. Substance P and a scrambled sequence of the 25-35 fragment were without any effect per se, but substance P blocked the stimulatory effect of fragment 25-35 on glutamate and aspartate release. In slices from aged rats the basal release of glutamate was significantly higher (260%) than that in young tissue, and the K(+)-induced release of both aspartate and glutamate was also higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Alzheimer Disease↗
PubMed1987

a-b palmar interdigital ridge-count in the Basque population.

The a-b palmar interdigital ridge count was analyzed in a sample of 841 males and 911 females of Basque origin. Bimanual differences were not found, against that a significant sexual dimorphism. The mean ridge count value is in the lower lange of the variability among White populations.

Dermatoglyphics↗
PubMed1985

Hand clasping and arm folding in the Basque population.

Hand clasping and arm folding have been analysed in 286 males and 455 females of the Basques. The results are compared with those from other Spanish populations. Examination of the association between hand clasping and arm folding shows a strong correlation between the right type of one and the left type of the other.

Ethnicity↗