101
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Iglesias T, Llanos S, López-Barahona M, Seliger B, Rodríguez-Peña A, Bernal J, Muñoz A. Induction of platelet-derived growth factor B/c-sis by the v-erbA oncogene in glial cells. Oncogene 1995; 10:1103-10. [PMID: 7700635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The v-erbA oncogene codes for a mutated form of the thyroid hormone receptor TR/c-erbA-alpha. Thyroid hormone (triiodothyronine, T3) regulates glial functions such as myelination and both astrocytes and oligodendrocytes have been shown to express thyroid hormone receptors (TRs). To study putative effects of v-erbA on glial precursors, we have expressed it in a glial clonal cell line established from early embryonal mouse brain. We have found that v-erbA increases cell survival in serum-free conditions. Moreover, v-erbA-expressing cells show a substantial growth in the presence of insulin or IGF-I, whereas normal and TR/c-erbA-over-expressing cells progressively degenerate. By Northern blotting, immunofluorescence, immunoprecipitation, and neutralization experiments, we show that v-erbA actions are mediated by an increase in the levels of PDGF B/c-sis mRNA and protein. We used anti-PDGF receptor and anti-phosphotyrosine antibodies to show the constitutive activation of PDGF receptors in B3.1 + v-erbA cells, and neutralizing anti-PDGF antibodies to demonstrate that v-erbA enhances the secretion of active PDGF into the culture medium. Our data indicate that v-erbA induces PDGF B/c-sis, a factor involved in the generation of gliomas, the most common central nervous system tumor in humans.
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102
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López-Barahona M, Fialka I, González-Sancho JM, Asunción M, González M, Iglesias T, Bernal J, Beug H, Muñoz A. Thyroid hormone regulates stromelysin expression, protease secretion and the morphogenetic potential of normal polarized mammary epithelial cells. EMBO J 1995; 14:1145-55. [PMID: 7720705 PMCID: PMC398192 DOI: 10.1002/j.1460-2075.1995.tb07098.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Stromelysins are a group of proteases which degrade the extracellular matrix and activate other secreted proteases. Stromelysin (ST)-1 and ST-2 genes are induced by tumor promoters, oncogenes and growth factors, and have been involved in acquisition of the malignant phenotype. We show here that the thyroid hormone (T3) increases ST-1 and ST-2 expression in a non-transformed mouse mammary epithelial cell line (EpH4) in a way that is dependent on the level of thyroid receptor/c-erbA (TR alpha-1) expression. In agreement with this, T3 increases the secreted stromelysin activity and enhances the gelatinolytic activity of type IV collagenase. We have also demonstrated that T3 affects the epithelial polarity of EpH4 cells, diminishing the transepithelial electrical resistance of monolayers cultured on permeable filters, causing an abnormal distribution of polarization markers and the disruption of the organized 3-D structures formed by these cells in type I collagen gels. These results indicate that the ligand-activated TR alpha-1 plays an important role in regulating the morphogenetic and invasive capacities of mammary epithelial cells. Because the c-erbA locus is altered in several types of carcinoma, an altered or deregulated TR alpha-1 expression may also be important for breast cancer development and metastasis.
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103
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Bernal J. Epilepsy in people with learning disabilities. Seizure 1995; 4:73-4. [PMID: 7788113 DOI: 10.1016/s1059-1311(05)80083-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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104
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Fernández T, Harmony T, Rodríguez M, Bernal J, Silva J, Reyes A, Marosi E. EEG activation patterns during the performance of tasks involving different components of mental calculation. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1995; 94:175-82. [PMID: 7536152 DOI: 10.1016/0013-4694(94)00262-j] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this study we demonstrate the existence of different patterns of EEG activation during the performance of 4 different tasks involving different components of mental calculation in normal subjects. The EEG was recorded in all monopolar leads of the 10/20 system using linked ear lobes as reference. Absolute and relative power were calculated in the delta (1.5-3.5 Hz), theta (3.5-7.5 Hz), alpha (7.5-12.5 Hz) and beta (12.5-19 Hz) bands. The tasks were presented randomly and the EEG segments preceding presentation of the stimulus were considered as the rest corresponding to the task requested by the stimulus. Tasks were of 4 different types, involving number comprehension, recognition of mathematical symbols, the calculation process and the spatial component. ANOVAs between the rest periods showed no differences in any band. Neither did ANOVAs between tasks. However, other variables (task minus rest), which were calculated as the differences in power between task and rest respectively, showed significant differences between tasks in the delta and beta bands in the frontal lobes. In addition, new variables were calculated as the difference between tasks, since many factors were common across several tasks. These variables correspond to the EEG change due to a specific component of mental calculation. Significant differences were obtained in delta and theta bands in right posterior areas and in the beta band in frontal areas. We concluded that the EEG differences observed during different components of mental calculation suggest the participation of different networks.
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105
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106
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Marosi E, Harmony T, Becker J, Reyes A, Bernal J, Fernández T, Rodríguez M, Silva J, Guerrero V. Electroencephalographic coherences discriminate between children with different pedagogical evaluation. Int J Psychophysiol 1995; 19:23-32. [PMID: 7790286 DOI: 10.1016/0167-8760(94)00059-n] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The relationship of reading-writing ability and EEG coherences was studied in 84 subjects from two age groups 7.0-8.9 and 9-11.2 years old. All children were divided into three groups according to their performance on a pedagogical test: ped1, normal children; ped2, children with mild problems; ped3, children with reading-writing disability. The following results were obtained: in general, children showed higher coherences in groups with poor performance in the delta, theta and beta bands. In the alpha band, higher coherence values were related to better performance. The exceptions to this general pattern were rare. Group ped2 had higher coherences in delta, theta and alpha bands than ped1 and ped3, in left temporal leads. In older children the same tendency was observed, but group differences in the theta, alpha and beta bands were few. In this age range, the significant group differences were almost all interhemispheric coherences. The discriminant analysis that classified subjects by their coherence values gave very good results, fact that demonstrates, that EEG coherence is a highly sensitive measurement indicating not only the existence of a reading-writing problem, but also the degree of its severity.
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107
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Alvarez-Dolado M, Iglesias T, Rodríguez-Peña A, Bernal J, Muñoz A. Expression of neurotrophins and the trk family of neurotrophin receptors in normal and hypothyroid rat brain. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1994; 27:249-57. [PMID: 7898308 DOI: 10.1016/0169-328x(94)90007-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Thyroid hormone deficiency has dramatic effects on rat brain maturation. The expression of genes encoding neurotrophins and the trk family of neurotrophin receptors has been evaluated in several brain regions of normal and of neonatal or adult hypothyroid rats to analyze whether they are subject to thyroid hormone action. We found that hypothyroidism decreased trk mRNA levels in its major site of expression, the striatum, on postnatal days 5 (P5; 45%) and 15 (P15; 25%) and also in adults (35%). In contrast, no differences in trkB or trkC mRNAs levels were observed in any brain region at studied ages. According to previous reports, p75LNGFR mRNA was elevated in hypothyroid cerebellum as compared to age-matched controls on P5 and P15. We have also observed a distinct pattern for neurotrophin genes. The level of NGF mRNA was 20-50% lower in the cortex, hippocampus, and cerebellum of hypothyroid rats on neonatal hypothyroid rats on P15 and also after adult-onset hypothyroidism. Treatment of neonatally-induced hypothyroid rats with a single injection of triiodothyronine led to the recovery of hippocampal but not cortex NGF mRNA levels to that of control animals. On the contrary, no differences in the relatively high expression of the two mRNAs encoding BDNF were observed in any brain area. In contrast to a recent report, we did not find a reduction in brain NT-3 mRNA levels in hypothyroid animals. If any, the effect of thyroid deficiency in the hippocampus and cortex seems to be an early upregulation of NT-3 expression.(ABSTRACT TRUNCATED AT 250 WORDS)
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108
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Iñiguez MA, Morte B, Rodriguez-Peña A, Muñoz A, Gerendasy D, Sutcliffe JG, Bernal J. Characterization of the promoter region and flanking sequences of the neuron-specific gene RC3 (neurogranin). BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1994; 27:205-14. [PMID: 7898304 DOI: 10.1016/0169-328x(94)90002-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
RC3 encodes a thyroid hormone-dependent, calmodulin-binding, protein kinase C substrate (neurogranin, p17) present in the dendritic spines of discrete neuronal populations in the forebrain. Its physiological role could be related to synaptic plasticity, memory, and other processes. In the present work we have isolated and sequenced 2.4 kbp of genomic DNA upstream from the origin of transcription and determined its nucleotide sequence. The major features of the RC3 promoter are the absence of TATA and CAAT boxes and the presence of an Initiator sequence surrounding the cap site. By sequence analysis we identified several cis-acting regulatory elements, among them response elements for retinoic acid and steroid (glucocorticoids/progesterone) hormone receptors. An oligonucleotide containing the retinoic acid responsive element bound to retinoic acid receptors specifically in vitro and conferred retinoic acid regulation to a heterologous promoter after transfection in COS-7 cells. Retinoic acid and dexamethasone, respectively, increased activity of the RC3 promoter in neuroblastoma cells when a deletion construct containing the retinoic acid and the glucocorticoid responsive elements was cotransfected with retinoic acid receptor or glucocorticoid receptor expression vectors. When added together all-trans retinoic acid and dexamethasone had additive effects. Despite the fact that RC3 expression in vivo is thyroid hormone-dependent, no evidence for the presence of a thyroid hormone responsive element was found within the 2.4 kbp flanking region analyzed and thyroid hormone did not increase reporter activity after cotransfection of suitable constructs with thyroid hormone receptor expression vectors. Our results suggest that the expression of RC3 in vivo could be subject to complex physiological signals, including retinoids and steroid hormones in addition to thyroid hormones.
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109
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Fernandez T, Silva J, Harmony T, Yanez G, Marosi E, Guerrero V, Rodriguez M, Bernal J, Reyes A. Children's EEG characteristics prior to the presentation of the stimulus related with the performance of mental tasks. Int J Psychophysiol 1994. [DOI: 10.1016/0167-8760(94)90326-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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110
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Caubín J, Iglesias T, Bernal J, Muñoz A, Márquez G, Barbero JL, Zaballos A. Isolation of genomic DNA fragments corresponding to genes modulated in vivo by a transcription factor. Nucleic Acids Res 1994; 22:4132-8. [PMID: 7937138 PMCID: PMC331900 DOI: 10.1093/nar/22.20.4132] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A new methodology for the identification of genes modulated by transcription factors in vivo is described. Mouse genomic DNA fragments bound by the thyroid hormone receptor (T3R) were selected and amplified in vitro. Subsequent hybridisation with biotinylated cDNA allowed the selection of those DNA fragments containing binding sites for T3R that corresponded to transcribed DNA. Expression analysis of the corresponding genes showed that more than 80% are indeed modulated by thyroid hormones in vivo in the liver. Together with the presence of consensus binding sites for T3R this result suggests that the selected DNA fragments may contain T3R transcriptional regulatory elements. This method, extensive to other ligand-modulated transcription factors, might be useful to all transcription factors with slight modifications.
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111
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Iglesias T, Llanos S, López-Barahona M, Pérez-Aranda A, Rodríguez-Peña A, Bernal J, Höhne A, Seliger B, Muñoz A. c-erbA and v-erbA modulate growth and gene expression of a mouse glial precursor cell line. CELL GROWTH & DIFFERENTIATION : THE MOLECULAR BIOLOGY JOURNAL OF THE AMERICAN ASSOCIATION FOR CANCER RESEARCH 1994; 5:697-704. [PMID: 7947384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The c-erbA alpha protooncogene coding for the thyroid hormone (T3) receptor (TR alpha 1) and the viral, mutated v-erbA oncogene were expressed in an immortal mouse glial cell line (B3.1) using retroviral vectors. c-erbA alpha expression led to a decrease in cell proliferation in high and low serum conditions, both in the presence and in the absence of T3. In serum-free medium, c-erbA-expressing cells (B3.1 + TR alpha 1) were completely arrested, whereas cells expressing v-erbA (B3.1 + v-erbA) showed a higher DNA synthesis rate than normal B3.1 cells. Although proliferation of all three cell types was stimulated by platelet-derived growth factor and basic fibroblast growth factor, differences were also observed in the response to these agents. B3.1 + TR alpha 1 cells were more sensitive to platelet-derived growth factor than B3.1 and B3.1 + v-erbA cells. In contrast, B3.1 cells responded to basic fibroblast growth factor better than B3.1 + TR alpha 1 or B3.1 + v-erbA cells. Insulin-like growth factor I potentiated the action of platelet-derived growth factor and basic fibroblast growth factor. Again, different responses to treatment with insulin-like growth factor I alone were observed; B3.1 + TR alpha 1 cells did not respond to it, whereas B3.1 + v-erbA cells showed a dramatic stimulation by this agent. Interestingly, in the presence of T3, the blockade in B3.1 + TR alpha 1 cell proliferation was accompanied by the down-regulation of the typical astrocytic genes, glial fibrillary acidic protein and vimentin. These hormone effects were not found in v-erbA-expressing cells. In addition, v-erbA inhibited the basal expression of the cyclic nucleotide phosphodiesterase gene, an oligodendrocytic marker.(ABSTRACT TRUNCATED AT 250 WORDS)
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112
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Pastor R, Bernal J, Rodríguez-Peña A. Unliganded c-erbA/thyroid hormone receptor induces trkB expression in neuroblastoma cells. Oncogene 1994; 9:1081-9. [PMID: 8134111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Neurotrophins are responsible for the differentiation and survival of neurons in the developing and in the adult nervous system. They bind to specific membrane receptors with tyrosine kinase activity whose prototype is the product of the trkA proto-oncogene. TrkB, a member of this family, is the receptor for the neurotrophins brain derived growth factor (BDNF) and neurotrophins-3, -4/5. In this study, we show that stable expression of the c-erbA proto-oncogene, which encodes the alpha 1-isoform of the nuclear receptor for thyroid hormone (Tr alpha 1) induces the expression of trkB mRNA with a concomitant decrease to undetectable levels of trkA and trkC mRNAs in the mouse neuroblastoma N2a cell line. trkB induction by c-erbA is ligand independent, since addition of T3 had no effect. The induced trkB transcript encodes a functional gp145trkB protein, which is phosphorylated on tyrosine in response to BDNF. Furthermore, induction of trkB mRNA is also caused by transient expression of either TR alpha 1 or beta 1 isoforms. Our results are compatible with the idea that there are certain pathways which are under control of unliganded thyroid hormone receptor, and that one of these pathways results in regulation of trk expression.
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MESH Headings
- Animals
- Brain-Derived Neurotrophic Factor
- Cell Differentiation/drug effects
- Colforsin/pharmacology
- Gene Expression Regulation, Neoplastic
- Mice
- Nerve Tissue Proteins/pharmacology
- Neuroblastoma/genetics
- Phosphorylation
- Proto-Oncogene Proteins/biosynthesis
- RNA, Messenger/biosynthesis
- Receptor Protein-Tyrosine Kinases/biosynthesis
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor, trkA
- Receptor, trkB
- Receptor, trkC
- Receptors, Growth Factor/genetics
- Receptors, Nerve Growth Factor/biosynthesis
- Receptors, Nerve Growth Factor/genetics
- Receptors, Thyroid Hormone/physiology
- Thyroid Hormones/pharmacology
- Transfection
- Tretinoin/pharmacology
- Tumor Cells, Cultured
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113
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Harmony T, Marosi E, Fernández T, Bernal J, Silva J, Rodríguez M, Reyes A, Fernández-Bouzas A, Alonso M, Mendizábal R. EEG coherences in patients with brain lesions. Int J Neurosci 1994; 74:203-26. [PMID: 7928106 DOI: 10.3109/00207459408987240] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
EEG coherence between all pairwise combinations of the 10/20 system was studied in two groups: control subjects and patients with space-occupying brain lesions. Coherence was separately computed for the delta, theta, alpha and beta bands. Comparisons between both groups showed highly significant differences in all bands. In the patients with lower coherence values, these differences were mainly in the alpha band. When intra-hemispheric coherences between controls and patients with left hemispheric lesions were compared, significant differences were observed only in the left hemisphere. Comparisons between controls and patients with lesions in the right hemisphere also showed significant differences only in the injured hemisphere. In patients, paired t tests between the values of the intra-hemispheric coherence in the left hemisphere and the corresponding values in the right hemisphere demonstrated that lower coherences were confined to the damaged hemisphere. Our conclusion is that in the presence of lesions disrupting cortex and adjacent white matter the coherence between this area and the remaining cortical areas is lower than normal due to impairment of the fibers that connect the damaged area with the rest of the brain.
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114
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Trachtenberg E, Keyeux G, Bernal J, Erlich H. HLA class II analysis by PCR/SSOP typing of nine Amerindian tribes and three African American populations from Colombia. Hum Immunol 1994. [DOI: 10.1016/0198-8859(94)91815-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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115
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López-Barahona M, Miñano M, Mira E, Iglesias T, Stunnenberg HG, Rodríguez-Peña A, Bernal J, Muñoz A. Retinoic acid posttranscriptionally up-regulates proteolipid protein gene expression in C6 glioma cells. J Biol Chem 1993; 268:25617-23. [PMID: 7503983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The proteolipid protein (PLP) gene codes for the major central nervous system myelin protein. We have studied the effects of different agents on the expression of the PLP gene in C6 glioma cells. Retinoic acid (RA), but not dexamethasone, estradiol, insulin, growth hormone, or vitamin D3, had a drastic effect, increasing 10-20-fold the level of PLP mRNA. Concomitantly, RA also induced the appearance of the corresponding immunoreactive protein. The increase in PLP RNA level showed a slow kinetics and was blocked by cycloheximide, suggesting a posttranscriptional regulation by RA. Nuclear run-on assays confirmed that the rate of PLP gene transcription was unchanged by RA. In contrast, we found that retinoic acid augmented PLP mRNA stability, causing a substantial increase in its half-life. RA action was independent of cell density, serum, or PDGF but was partially inhibited by bFGF. On the other hand, thyroid hormone caused a moderate increase in PLP mRNA levels in C6 cells but only when the low numbers of thyroid receptors in these cells were increased by retrovirally mediated expression of an exogenous c-erbA/TR alpha-1 gene. Our results indicate that RA specifically up-regulates PLP expression in glioma C6 cells at a posttranscriptional level by increasing PLP RNA half-life.
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116
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López-Barahona M, Miñano M, Mira E, Iglesias T, Stunnenberg HG, Rodríguez-Peña A, Bernal J, Muñoz A. Retinoic acid posttranscriptionally up-regulates proteolipid protein gene expression in C6 glioma cells. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74434-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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117
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García-Fernández LF, Iñiguez MA, Rodríguez-Peña A, Muñoz A, Bernal J. Brain-specific prostaglandin D2 synthetase mRNA is dependent on thyroid hormone during rat brain development. Biochem Biophys Res Commun 1993; 196:396-401. [PMID: 8216319 DOI: 10.1006/bbrc.1993.2262] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have previously described several cDNA clones whose expression is affected by thyroid hormone during rat brain development. We now report the identification of one of these, the E2 clone, as the brain-specific prostaglandin D2 (PGD2) synthetase gene. Sequence comparison shows a nearly complete identity between the 356 nucleotides of the E2 clone and nucleotides 403 to 759 of PGD2 synthetase cDNA. The pattern of E2 expression corresponds to that expected for brain specific PGD2 synthetase gene, i.e. the corresponding mRNA is not detected in any other tissue analyzed apart of the brain, and it was present at different levels in all brain regions. Hypothyroidism decreased E2 mRNA concentrations in cerebral cortex and cerebellum. Control of the level of expression of PGD2 synthetase gene may contribute the complex effects of thyroid hormone on brain development and function.
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118
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Harmony T, Fernández-Bouzas A, Marosi E, Fernández T, Bernal J, Rodríguez M, Reyes A, Silva J, Alonso M, Casian G. Correlation between computed tomography and voltage and current source density spectral EEG parameters in patients with brain lesions. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1993; 87:196-205. [PMID: 7691550 DOI: 10.1016/0013-4694(93)90019-r] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In a group of patients with space-occupying brain lesions, CT measurements were correlated with absolute power (AP) and relative power (RP) of the delta, theta, alpha and beta EEG bands, calculated from the raw EEG potentials (EEGp) and from the Laplacian estimates also called "current source densities" (CSD). Rank correlations were calculated between the number of abnormal values in each band and the following CT measures: volume of the lesion and of the edema, density of the edema, percentage of ventricular collapse and midline shift. Abnormal spectral values are those which are significantly higher than the norm for the same age, in the delta and theta bands, and significantly lower in the alpha and beta bands. Spectral parameters obtained from the CSD showed higher correlations with CT measures than those calculated from the EEGp. In the Laplacian, all CT measures had a significant correlation with delta AP. Theta AP was significantly correlated with the volume and density of the edema, as well as with midline shift. Significant correlations were also observed with delta and alpha RP. However, changes in RP were considered to be a consequence of the increase in delta AP. Canonical correlation analyses between AP and RP calculated from EEGp or CSD and the first 3 CT measures showed that the volume of the lesion was only correlated with delta AP and RP. The volume and density of the edema showed a significant correlation with delta, theta and alpha AP calculated from EEGp and only with theta and alpha AP in the Laplacian. Since the EEGp tends to produce a more extensive and diffuse picture of abnormality, whereas the Laplacian acts as a spatial filter emphasizing local sources over distant sources, we concluded that edema is related not to delta activity, but to the theta and alpha power.
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119
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Marosi E, Harmony T, Becker J, Bernal J, Reyes A, Rodriguez M, Fernandez T. Sex differences in EEG coherence in normal children. Int J Neurosci 1993; 72:115-21. [PMID: 8225795 DOI: 10.3109/00207459308991628] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The idea that sex differences in the execution of different mental tasks mean a different cerebral organization met contradictory results. Sex differences in brain electrical activity were reported by various authors. The EEG coherences show functional and anatomical interrelation, so they may reveal differences in brain organization. This paper tries to demonstrate how sex differences are manifested in EEG coherences, in 42 right-handed control children, 18 girls and 24 boys, aged 7.6 to 13.3. Since the effect of age is high on EEG measurements, regression against age was calculated and eliminated. The Z-transformed coherence values were compared by Student's t-test. The results obtained showed that girls had higher right intrahemispheric coherence values than boys in all bands. These sex differences were more numerous in the theta band. The interhemispheric differences were slight and girls had higher coherences in all bands except for the alpha band, where boys had higher interhemispheric coherence than girls. These results show slight but consistent differences in the functional organization of the right hemisphere by sex and reveal the necessity to elaborate separated EEG norms for boys and girls.
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120
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Iñiguez MA, Rodriguez-Peña A, Ibarrola N, Aguilera M, Muñoz A, Bernal J. Thyroid hormone regulation of RC3, a brain-specific gene encoding a protein kinase-C substrate. Endocrinology 1993; 133:467-73. [PMID: 8344193 DOI: 10.1210/endo.133.2.8344193] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
RC3 is a brain-specific mRNA expressed in discrete neuronal groups of the forebrain that encodes a 78-amino acid protein, also called neurogranin, a calmodulin-binding, protein kinase-C substrate. Expression of RC3 mRNA was studied in normal and hypothyroid animals during the first month of life. Hypothyroid rats were produced by administration of methyl-mercapto-imidazol to the pregnant dams and subsequent surgical thyroidectomy on postnatal day 5 of the neonates. As studied by slot-blotting of total cerebrum poly(A)+ RNA, RC3 mRNA accumulates in normal brain from the fifth to seventh postnatal day, reaching maximal levels around days 10-12. RC3 mRNA accumulation in hypothyroid animals was blunted, and the maximal levels attained were about 30-50% of normal values. The effect of hypothyroidism on steady state mRNA levels was also observed by Northern blotting of RNA from cerebral cortex and striatum. As studied by immunoblotting using a polyclonal antibody, hypothyroidism also led to clear decreases in the amount of the RC3 protein in extracts from cerebral cortex, striatum, and hippocampus. A single administration of 10 micrograms T4 to hypothyroid rats on postnatal day 12 led to a steady increase in striatal RC3 mRNA from levels that were about 40% of normal to about 70% of normal at 16 h and 115% of normal at 48 h. In contrast to the effect on RC3, hypothyroidism did not affect developmental expression of the mRNA encoding GAP-43, another brain protein kinase-C substrate of axonal localization. RC3 is, thus, one of the few known neuronal genes whose expression is influenced by thyroid hormone in the brain. Thyroid hormone is required for an appropriate level of expression, not for the developmentally programmed timing of expression of the RC3 gene.
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121
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Barry SR, Bernal J. Antimalarial drugs inhibit calcium-dependent backward swimming and calcium currents in Paramecium calkinsi. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1993; 172:457-66. [PMID: 8315608 DOI: 10.1007/bf00213527] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The antimalarial drugs, quinacrine, chloroquine, quinine, primaquine, and mefloquine, share structural similarities with W-7, a compound that inhibits calcium-dependent backward swimming and calcium currents in Paramecium. Therefore, we tested whether antimalarial drugs also inhibit backward swimming and calcium currents in P. calkinsi. When the Paramecium is depolarized in high potassium medium, voltage-dependent calcium channels in the ciliary membrane open causing the cell to swim backward for 30 to 70 s. Application of calcium channel inhibitors, such as W-7, reduce the duration of backward swimming. In 0.05 mM calcium, quinacrine, mefloquine, quinine, chloroquine, primaquine and W-7 all reduced the duration of backward swimming. These effects were seen in sodium-containing and sodium-free high potassium solutions as well as sodium-free depolarizing solutions containing potassium channel blockers. In these low calcium solutions, backward swimming was inhibited by 50% at concentrations ranging from 100 nM to 30 microM. At higher calcium concentrations (1 mM or 15 mM), the effects of the antimalarials and W-7 were reduced. The effects of quinacrine and W-7 were tested directly on calcium currents using the two microelectrode voltage clamp technique. In 15 mM calcium, 100 microM quinacrine and 100 microM W-7 reduced the peak calcium current by 51% and 42%, respectively. Thus, antimalarial drugs reduce calcium currents in Paramecium calkinsi.
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Muñoz A, Wrighton C, Seliger B, Bernal J, Beug H. Thyroid hormone receptor/c-erbA: control of commitment and differentiation in the neuronal/chromaffin progenitor line PC12. J Biophys Biochem Cytol 1993; 121:423-38. [PMID: 8385673 PMCID: PMC2200090 DOI: 10.1083/jcb.121.2.423] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The c-erbA proto-oncogenes encode nuclear receptors for thyroid hormone (T3), a hormone intimately involved in mammalian brain maturation. To study thyroid hormone receptor (TR) action on neuronal cells in vitro, we expressed the chicken c-erbA/TR alpha-1 as well as its oncogenic variant v-erbA in the adrenal medulla progenitor cell line PC12. In the absence of T3, exogenous TR alpha-1 inhibits NGF-induced neuronal differentiation and represses neuron-specific gene expression. In contrast, TR alpha-1 allows normal differentiation and neuronal gene expression to occur in the presence of T3. Finally, TR alpha-1-expressing cells become NGF-responsive for proliferation when T3 is absent, but NGF-dependent for survival in presence of T3. A similar differentiation induction by NGF plus T3 was observed in a central nervous system-derived neuronal cell line (E 18) expressing exogenous TR alpha-1. Together with the finding that TR alpha-1 constitutively blocked dexamethasone-induced differentiation of PC12 cells into the chromaffin pathway, these results suggest that TR alpha-1 plays an important role in regulating commitment and maturation of neuronal progenitors. In contrast, the v-erbA oncogene, a mutated, oncogenic version of TR alpha-1, partially but constitutively inhibited NGF-induced neuronal differentiation of PC12 cells and potentiated dexamethasone-induced chromaffin differentiation, giving rise to an aberrant "interlineage" cell phenotype.
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Abstract
Voltage-dependent calcium channels play a critical role in many cell functions and in many cell types ranging from protozoa to vertebrates. We have shown previously that guanine nucleotides modulate the calcium action potential and the duration of backward swimming in Paramecium, both indirect measurements of calcium channel function. To determine whether guanine nucleotides to indeed alter calcium currents, the inward calcium current (ICa) in Paramecium calkinsi was studied. First, the calcium current was characterized. The magnitude of ICa increased as the extracellular calcium concentration was increased from 0.5 to 50 mmol l-1, unlike the situation in freshwater species of Paramecium where the inward calcium current magnitude is maximal when extracellular calcium levels reach 1 mmol l-1. Inorganic compounds (NiCl2 at 10 mumol l-1 and CdCl2 at 1 mmol l-1) and organic compounds (naphthalene sulfonamides, W-7 and W-12-Br at 100 and 2 mumol l-1, respectively) reduced ICa. Regardless of the holding membrane potential (from −80 to −20 mV), the threshold activation for ICa was at −10 mV and the maximum value of ICa was reached at +20 mV, suggesting that there is only one type of calcium channel in P. calkinsi. Second, we injected GTP gamma S, GTP and GDP beta S into voltage-clamped cells while monitoring calcium and/or potassium currents. GTP gamma S increased the magnitude of ICa by 42 +/− 6% (mean +/− S.D., N = 5) and the effect was irreversible, GTP increased the magnitude of ICa by 37 +/− 4% (N = 4) in a reversible manner, and GDP beta S decreased ICa by 57 +/− 8% (N = 3) irreversibly. The outward potassium currents did not change when GTP gamma S was injected into the cells. These results support the hypothesis that injection of guanine nucleotides modulates the voltage-dependent calcium channel in P. calkinsi, presumably by activating G-protein-dependent processes.
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Rodriguez-Peña A, Ibarrola N, Iñiguez MA, Muñoz A, Bernal J. Neonatal hypothyroidism affects the timely expression of myelin-associated glycoprotein in the rat brain. J Clin Invest 1993; 91:812-8. [PMID: 7680668 PMCID: PMC288032 DOI: 10.1172/jci116301] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Congenital hypothyroidism strongly affects myelination. To assess the role of thyroid hormone on myelin gene expression, we have studied the effect of hypothyroidism on the steady state levels of myelin-associated glycoprotein (MAG) and its mRNA in rat brain during the first postnatal month. As studied by immunoblot analysis of several brain regions, MAG increased from days 10-15 onwards, reaching constant levels by days 20-25. Hypothyroid samples showed a delay in the accumulation of MAG that was more severe in rostral regions, such as cortex and hippocampus. The effect of hypothyroidism on the accumulation of the protein correlated with mRNA levels. MAG mRNA started to accumulate in the cerebrum of normal animals by postnatal day 7, reaching maximal levels by day 20. Hypothyroid rats showed a delay of several days in the onset of mRNA expression, increasing thereafter at the same rate as in normal animals, and eventually reaching similar values. When individual brain regions were analyzed, we found strong regional differences in the effect of hypothyroidism. The cerebral cortex was most affected, with messenger levels lower than in normal animals at all ages. In more caudal regions differences between control and hypothyroid rats were evident only at the earlier stages of myelination, with spontaneous recovery at later ages. By run on analysis, we found no differences in transcriptional activities of the MAG gene in normal, hypothyroid, or T4-treated rats. Therefore, the effects of hypothyroidism on MAG mRNA and protein levels were most likely caused by decreased mRNA stability. We propose that thyroid hormone contributes to enhanced myelin gene expression by affecting the stability of newly transcribed mRNA in the early phases of myelination.
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Fernández T, Harmony T, Rodríguez M, Reyes A, Marosi E, Bernal J. Test-retest reliability of EEG spectral parameters during cognitive tasks: I. Absolute and relative power. Int J Neurosci 1993; 68:255-61. [PMID: 8063530 DOI: 10.3109/00207459308994280] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We analyzed test-retest reliability of Absolute (AP) and Relative Power (RP) during rest and during two cognitive tasks: one verbal, the search for a synonym, and the other consisting of mental arithmetic calculations. Under all conditions during the experiment the subjects had their eyes open. The experiment was performed twice, with a month's interval between each trial. Monopolar recordings were obtained in F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6 and Cz vs A1A2. Differences between sessions were observed mainly during rest with eyes open in the lapha band, with higher AP during the first session. During rest it is extremely difficult to control for the state of vigilance, anxiety and thinking. However, during cognitive tasks a more rigid control of the state of vigilance and thinking is obtained. Therefore, AP and RP are very reliable parameters for analyzing EEG during mental tasks. Comparisons between conditions were also made. The only significant differences observed were in delta AP in the second session, with more power during the cognitive tasks in C3 and O2. MANOVAs using the values of AP in the four bands showed significant differences between conditions in C3, C4, P3, O2 and T4. Several factors that may be involved in the origin of delta activity, including eye movements, slow potential shifts and the inhibition of cholinergic projections to the cortex, are discussed.
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