14 results on '"German Calderon"'
Search Results
2. A Critical Reading of Latin American Bioethics
- Author
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Legarda, Germán Calderón, Pessini, Léo, editor, Paul de Barchifontaine, Christian, editor, and Lolas Stepke, Fernando, editor
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- 2010
- Full Text
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3. Essential role of brain-derived neurotrophic factor in the regulation of serotonin transmission in the basolateral amygdala
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Shabrine S. Daftary, German Calderon, and Maribel Rios
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Male ,Serotonin ,Patch-Clamp Techniques ,Tropomyosin receptor kinase B ,Neurotransmission ,Serotonergic ,Synaptic Transmission ,Article ,Mice ,Neurotrophic factors ,medicine ,Animals ,Chromatography, High Pressure Liquid ,In Situ Hybridization ,Brain-derived neurotrophic factor ,biology ,Reverse Transcriptase Polymerase Chain Reaction ,Brain-Derived Neurotrophic Factor ,Pyramidal Cells ,General Neuroscience ,Amygdala ,Immunohistochemistry ,Mice, Mutant Strains ,medicine.anatomical_structure ,nervous system ,Synaptic plasticity ,biology.protein ,Psychology ,Neuroscience ,Neurotrophin ,Basolateral amygdala - Abstract
Human and animal model studies have linked brain-derived neurotrophic factor (BDNF) with the etiology of anxiety disorders. This pleiotropic neurotrophin and its receptor, TrkB, promote neuronal survival, differentiation and synaptic plasticity. Here we interrogated the role of BDNF in serotonergic neurotransmission in the basolateral amygdala (BLA), a limbic brain region associated with the neurobiology of anxiety. We found that both GABAergic and pyramidal projection neurons in the wild-type BLA contained TrkB receptors. Examination of BDNF 2L/2LCk-Cre mutant mice with brain-selective depletion of BDNF revealed mild decreases in serotonin content in the BLA. Notably, whole cell recordings in BLA pyramidal cells uncovered significant alterations in 5-HT 2 -mediated regulation of GABAergic and glutamatergic transmission in BDNF 2L/2LCk-Cre mutant mice that result in a hyperexcitable circuit. These changes were associated with decreased expression of 5-HT 2 receptors. Collectively, the results indicate a required role of BDNF in serotonin transmission in the BLA. Furthermore, they suggest a mechanism underlying the reported increase in anxiety-like behavior elicited by perturbed BDNF signaling.
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- 2012
4. Depletion of central BDNF in mice impedes terminal differentiation of new granule neurons in the adult hippocampus
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Lakshmanan K. Iyer, Jason P. Chan, Joshua Cordeira, German Calderon, and Maribel Rios
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Male ,Transcription, Genetic ,Cellular differentiation ,Hippocampal formation ,Biology ,Hippocampus ,Calbindin ,Article ,gamma-Aminobutyric acid ,Mice ,Cellular and Molecular Neuroscience ,Cell Movement ,medicine ,Animals ,Receptor, trkB ,Molecular Biology ,gamma-Aminobutyric Acid ,Cell Proliferation ,Mice, Knockout ,Neurons ,Brain-derived neurotrophic factor ,Brain-Derived Neurotrophic Factor ,Stem Cells ,Dentate gyrus ,Neurogenesis ,Cell Differentiation ,Cell Biology ,Receptors, GABA-A ,Mice, Inbred C57BL ,nervous system ,Female ,Calretinin ,Neuroscience ,medicine.drug - Abstract
Granule neurons generated in the adult mammalian hippocampus synaptically integrate to facilitate cognitive function and antidepressant efficacy. Here, we investigated the role of BDNF in facilitating their maturation in vivo. We found that depletion of central BDNF in mice elicited an increase in hippocampal cell proliferation without affecting cell survival or fate specification. However, new mutant neurons failed to fully mature as indicated by their lack of calbindin, reduced dendritic differentiation and an accumulation of calretinin(+) immature neurons in the BDNF mutant dentate gyrus. Furthermore, the facilitating effects of GABA(A) receptor stimulation on neurogenesis were absent in the mutants, suggesting that defects might be due to alterations in GABA signaling. Transcriptional analysis of the mutant hippocampal neurogenic region revealed increases in markers for immature neurons and decreases in neuronal differentiation facilitators. These findings demonstrate that BDNF is required for the terminal differentiation of new neurons in the adult hippocampus.
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- 2008
5. Myosin II Regulatory Light Chain Is Required for Trafficking of Bile Salt Export Protein to the Apical Membrane in Madin-Darby Canine Kidney Cells
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Wayne Chan, German Calderon, Hiroshi Hosoya, Amy L. Swift, Jamie Moseley, Irwin M. Arias, Shaohua Li, and Daniel F. Ortiz
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Immunoprecipitation ,Recombinant Fusion Proteins ,ATP-binding cassette transporter ,Plasma protein binding ,Biology ,Kidney ,Biochemistry ,Cell Line ,Bile Acids and Salts ,Dogs ,Myosin ,Animals ,Secretion ,Phosphorylation ,Molecular Biology ,Myosin Type II ,Bile Canaliculi ,Kidney metabolism ,Cell Biology ,Apical membrane ,Molecular biology ,Transport protein ,Protein Transport ,Microscopy, Fluorescence ,Carrier Proteins ,Plasmids ,Protein Binding - Abstract
BSEP, MDR1, and MDR2 ATP binding cassette transporters are targeted to the apical (canalicular) membrane of hepatocytes, where they mediate ATP-dependent secretion of bile acids, drugs, and phospholipids, respectively. Sorting to the apical membrane is essential for transporter function; however, little is known regarding cellular proteins that bind ATP binding cassette proteins and regulate their trafficking. A yeast two-hybrid screen of a rat liver cDNA library identified the myosin II regulatory light chain, MLC2, as a binding partner for BSEP, MDR1, and MDR2. The interactions were confirmed by glutathione S-transferase pulldown and co-immunoprecipitation assays. BSEP and MLC2 were overrepresented in a rat liver subcellular fraction enriched in canalicular membrane vesicles, and MLC2 colocalized with BSEP in the apical domain of hepatocytes and polarized WifB, HepG2, and Madin-Darby canine kidney cells. Expression of a dominant negative, non-phosphorylatable MLC2 mutant reduced steady state BSEP levels in the apical domain of polarized Madin-Darby canine kidney cells. Pulse-chase studies revealed that Blebbistatin, a specific myosin II inhibitor, severely impaired delivery of newly synthesized BSEP to the apical surface. These findings indicate that myosin II is required for BSEP trafficking to the apical membrane.
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- 2005
6. Epstein-Barr Virus Latent Membrane Protein LMP-2A Is Sufficient for Transactivation of the Human Endogenous Retrovirus HERV-K18 Superantigen
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Natalie Sutkowski, German Calderon, Gang Chen, and Brigitte T. Huber
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Gene Expression Regulation, Viral ,Transcriptional Activation ,Herpesvirus 4, Human ,viruses ,Immunology ,Endogenous retrovirus ,chemical and pharmacologic phenomena ,macromolecular substances ,Biology ,medicine.disease_cause ,Microbiology ,Herpesviridae ,Virus ,Cell Line ,Viral Matrix Proteins ,Transactivation ,Viral Envelope Proteins ,hemic and lymphatic diseases ,Virology ,Virus latency ,medicine ,Superantigen ,Animals ,Humans ,Superantigens ,Endogenous Retroviruses ,hemic and immune systems ,medicine.disease ,Epstein–Barr virus ,Virus Latency ,Virus-Cell Interactions ,Membrane protein ,Insect Science - Abstract
Superantigens are microbial proteins that strongly stimulate T cells. We described previously that the Epstein-Barr virus (EBV) transactivates a superantigen encoded by the human endogenous retrovirus, HERV-K18. We now report that the transactivation is dependent upon the EBV latent cycle proteins. Moreover, LMP-2A is sufficient for induction of HERV-K18 superantigen activity.
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- 2004
7. Identification of HAX-1 as a Protein That Binds Bile Salt Export Protein and Regulates Its Abundance in the Apical Membrane of Madin-Darby Canine Kidney Cells
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Amy L. Swift, German Calderon, Shaohua Li, Irwin M. Arias, James Moseley, and Daniel F. Ortiz
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Time Factors ,ATP-binding cassette transporter ,Biochemistry ,chemistry.chemical_compound ,Internalization ,ATP Binding Cassette Transporter, Subfamily B, Member 11 ,Phospholipids ,Genes, Dominant ,Glutathione Transferase ,media_common ,biology ,Reverse Transcriptase Polymerase Chain Reaction ,Vesicle ,Multidrug resistance-associated protein 2 ,Microfilament Proteins ,Cell biology ,Protein Transport ,Liver ,RNA Interference ,Cortactin ,Plasmids ,Protein Binding ,Subcellular Fractions ,ATP Binding Cassette Transporter, Subfamily B ,media_common.quotation_subject ,Immunoblotting ,Molecular Sequence Data ,Transfection ,Models, Biological ,Cell Line ,Bile Acids and Salts ,Dogs ,Cations ,Two-Hybrid System Techniques ,Escherichia coli ,Animals ,Humans ,Biotinylation ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Amino Acid Sequence ,Molecular Biology ,Adaptor Proteins, Signal Transducing ,Sequence Homology, Amino Acid ,Cell Membrane ,Proteins ,Biological Transport ,Transporter ,Cell Biology ,Glutathione ,Apical membrane ,Precipitin Tests ,Rats ,Microscopy, Fluorescence ,chemistry ,Protein Biosynthesis ,Hepatocytes ,biology.protein ,ATP-Binding Cassette Transporters ,Protein Processing, Post-Translational - Abstract
ATP-binding cassette (ABC)-type proteins are essential for bile formation in vertebrate liver. BSEP, MDR1, MDR2, and MRP2 ABC transporters are targeted to the apical (canalicular) membrane of hepatocytes where they execute ATP-dependent transport of bile acids, drugs, amphipathic cations, phospholipids, and conjugated organic anions, respectively. Changes in activity and abundance of transporters in the canalicular membrane regulate bile flow; however, little is known regarding cellular proteins that bind ABC transporters and regulate their trafficking. A yeast two-hybrid screen identified HAX-1 as a binding partner for BSEP, MDR1, and MDR2. The interactions were validated biochemically by glutathione S-transferase pull-down and co-immunoprecipitation assays. BSEP and HAX-1 were over-represented in rat liver subcellular fractions enriched for canalicular membrane vesicles, microsomes, and clathrin-coated vesicles. HAX-1 was bound to BSEP, MDR1, and MDR2 in canalicular membrane vesicles and co-localized with BSEP and MDR1 in the apical membrane of Madin-Darby canine kidney (MDCK) cells. RNA interference of HAX-1 increased BSEP levels in the apical membrane of MDCK cells by 71%. Pulse-chase studies indicated that HAX-1 depletion did not affect BSEP translation, post-translational modification, delivery to the plasma membrane, or half-life. HAX-1 depletion resulted in an increased peak of metabolically labeled apical membrane BSEP at 4 h and enhanced retention at 6 and 9 h. HAX-1 also interacts with cortactin. Expression of dominant negative cortactin increased steady state levels of BSEP 2-fold in the apical membrane of MDCK cells, as did expression of dominant negative EPS15. These findings suggest that HAX-1 and cortactin participate in BSEP internalization from the apical membrane.
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- 2004
8. Identification of viral infections in the prostate and evaluation of their association with cancer
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Jesús Ancer-Rodríguez, Augusto Rojas-Martinez, Raquel Garza-Guajardo, Ana María Rivas-Estilla, Joke Beuten, Lauro S. Gómez-Guerra, Robin J. Leach, Teresa L. Johnson-Pais, German Calderon-Cardenas, Mario A. Hernandez-Ordoñez, Rocio Ortiz-Lopez, Idelma B. Morales-Rodriguez, and Margarita L Martinez-Fierro
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Adult ,Male ,Human cytomegalovirus ,Cancer Research ,Tumor Virus Infections ,Genotype ,viruses ,Cytomegalovirus ,Simian virus 40 ,Polymerase Chain Reaction ,lcsh:RC254-282 ,Prostate cancer ,Prostate ,Germany ,Endoribonucleases ,Genetics ,medicine ,Humans ,Papillomaviridae ,Aged ,Aged, 80 and over ,biology ,HPV infection ,Prostatic Neoplasms ,virus diseases ,Cancer ,Middle Aged ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,biology.organism_classification ,medicine.disease ,JC Virus ,Virology ,medicine.anatomical_structure ,Oncology ,BK Virus ,Case-Control Studies ,DNA, Viral ,Gammaretrovirus ,Research Article - Abstract
Background Several viruses with known oncogenic potential infect prostate tissue, among these are the polyomaviruses BKV, JCV, and SV40; human papillomaviruses (HPVs), and human cytomegalovirus (HCMV) infections. Recently, the Xenotropic Murine Leukemia Virus-related gammaretrovirus (XMRV) was identified in prostate tissue with a high prevalence observed in prostate cancer (PC) patients homozygous for the glutamine variant of the RNASEL protein (462Q/Q). Association studies with the R462Q allele and non-XMRV viruses have not been reported. We assessed associations between prostate cancer, prostate viral infections, and the RNASEL 462Q allele in Mexican cancer patients and controls. Methods 130 subjects (55 prostate cancer cases and 75 controls) were enrolled in the study. DNA and RNA isolated from prostate tissues were screened for the presence of viral genomes. Genotyping of the RNASEL R462Q variant was performed by Taqman method. Results R/R, R/Q, and Q/Q frequencies for R462Q were 0.62, 0.38, and 0.0 for PC cases and 0.69, 0.24, and 0.07 for controls, respectively. HPV sequences were detected in 11 (20.0%) cases and 4 (5.3%) controls. XMRV and HCMV infections were detected in one and six control samples, respectively. The risk of PC was significantly increased (Odds Ratio = 3.98; 95% CI: 1.17-13.56, p = 0.027) by infection of the prostatic tissue with HPV. BKV, JCV, and SV40 sequences were not detected in any of the tissue samples examined. Conclusions We report a positive association between PC and HPV infection. The 462Q/Q RNASEL genotype was not represented in our PC cases; thus, its interaction with prostate viral infections and cancer could not be evaluated.
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- 2010
9. Diminished diet-induced hyperglycemia and dyslipidemia and enhanced expression of PPARalpha and FGF21 in mice with hepatic ablation of brain-derived neurotropic factor
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German Calderon, Maribel Rios, and Sarah Teillon
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Male ,medicine.medical_specialty ,FGF21 ,Endocrinology, Diabetes and Metabolism ,Alpha (ethology) ,Biology ,chemistry.chemical_compound ,Mice ,Endocrinology ,Insulin resistance ,Downregulation and upregulation ,Internal medicine ,medicine ,Hyperinsulinemia ,Glucose homeostasis ,Animals ,PPAR alpha ,Aspartate Aminotransferases ,Triglycerides ,Dyslipidemias ,Cholesterol ,Brain-Derived Neurotrophic Factor ,Alanine Transaminase ,medicine.disease ,Dietary Fats ,Mice, Mutant Strains ,Fibroblast Growth Factors ,Mice, Inbred C57BL ,Disease Models, Animal ,chemistry ,Liver ,Hyperglycemia ,Female ,Insulin Resistance ,Dyslipidemia ,Signal Transduction - Abstract
Brain-derived neurotropic factor (BDNF) mediates many aspects of neuronal function, and plays a chief role in the central regulation of energy balance. In the periphery, it is expressed in organs involved in energy, lipid, and glucose homeostasis, including the liver, but its role there remains unclear. Here, we describe studies examining the effect of selectively depleting hepatic BDNF. Liver-specific mutant mice exhibited normal food intake and body weights when fed standard chow or high-fat diets (HFDs). However, whereas HFD intake induced mild hyperglycemia and hyperinsulinemia in wild-types (WTs), liver-specific BDNF mutants were protected from these effects. Serum levels of cholesterol and triglycerides were also elevated in HFD-fed WTs, but they were normal or slightly increased in BDNF mutants. Furthermore, whereas WTs fed HFD exhibited elevated levels of circulating alanine aminotransferase and aspartate aminotransferase, BDNF mutant males fed a similar diet had a normal content of both enzymes. Molecular analysis indicated that the livers of BDNF mutants fed HFD contained elevated levels of peroxisome proliferator-activated receptor α (Pparα or Ppara as listed in the MGI Database) and fibroblast growth factor 21 (Fgf21) transcripts compared with WTs. This is a notable finding as this pathway has anti-diabetic and lipid clearance effects. Accordingly, genes involved in lipid and glucose handling and targets of PPARα and FGF21 were upregulated in the BDNF mutant livers. The collective data indicate that hepatic BDNF might facilitate the emergence of insulin resistance, dyslipidemia, and liver disease following HFD challenge by suppressing PPARα and FGF21.
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- 2010
10. Selective deletion of Bdnf in the ventromedial and dorsomedial hypothalamus of adult mice results in hyperphagic behavior and obesity
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Maribel Rios, German Calderon, Thaddeus J Unger, Leila C Bradley, and Miguel Sena-Esteves
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medicine.medical_specialty ,Time Factors ,media_common.quotation_subject ,Genetic Vectors ,Green Fluorescent Proteins ,Hypothalamus, Middle ,Hindbrain ,Hyperlipidemias ,Tropomyosin receptor kinase B ,Hyperphagia ,Energy homeostasis ,Mice ,Neurotrophic factors ,Internal medicine ,Hyperinsulinism ,medicine ,Animals ,Receptor, trkB ,Obesity ,media_common ,Brain-derived neurotrophic factor ,Mice, Knockout ,biology ,Behavior, Animal ,General Neuroscience ,Brain-Derived Neurotrophic Factor ,Body Weight ,Appetite ,Feeding Behavior ,Articles ,Mice, Inbred C57BL ,Endocrinology ,Glucose ,nervous system ,Gene Expression Regulation ,Hypothalamus ,Hyperglycemia ,biology.protein ,Psychology ,Neuroscience ,Proto-Oncogene Proteins c-fos ,Gene Deletion ,Neurotrophin - Abstract
Brain-derived neurotrophic factor (BDNF) and its receptor TrkB are expressed in several hypothalamic and hindbrain nuclei involved in regulating energy homeostasis, developmentally and in the adult animal. Their depletion during the fetal or early postnatal periods when developmental processes are still ongoing elicits hyperphagic behavior and obesity in mice. Whether BDNF is a chief element in appetite control in the mature brain remains controversial. The required sources of this neurotrophin are also unknown. We show that glucose administration rapidly induced BDNF mRNA expression, mediated byBdnfpromoter 1, and TrkB transcription in the ventromedial hypothalamus (VMH) of adult mice, consistent with a role of this pathway in satiety. Using viral-mediated selective knock-down of BDNF in the VMH and dorsomedial hypothalamus (DMH) of adult mice, we were able to elucidate the physiological relevance of BDNF in energy balance regulation. Site-specific mutants exhibited hyperphagic behavior and obesity but normal energy expenditure. Furthermore, intracerebroventricular administration of BDNF triggered an immediate neuronal response in multiple hypothalamic nuclei in wild-type mice, suggesting that its anorexigenic actions involve short-term mechanisms. Locomotor, aggressive, and depressive-like behaviors, all of which are associated with neural circuits involving the VMH, were not altered in VMH/DMH-specific BDNF mutants. These findings demonstrate that BDNF is an integral component of central mechanisms mediating satiety in the adult mouse and, moreover, that its synthesis in the VMH and/or DMH is required for the suppression of appetite.
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- 2007
11. Análisis costo-efectividad en depresión,una perspectiva ética
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Germán Calderón L, Martha Edith Oyuela M, and Monica Rincón Roncancio
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Depresión ,Estudios fármaco-económicos ,análisis costo-efectividad ,Ética ,Medical philosophy. Medical ethics ,R723-726 ,Ethics ,BJ1-1725 - Abstract
La depresión es uno de los más comunes y más serios problemas de la salud mental que se presenta hoy en día. Los análisis económicos en salud se han convertido en una herramienta fundamental para la toma de decisiones en políticas en salud y en procurar mayor bienestar a las personas, por lo que deben ser evaluados y aplicados de la mejor forma
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- 2015
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12. Análisis costo-efectividad en depresión, una perspectiva ética
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Germán Calderon L, Martha Edith Oyuela M, and Mónica Rincón Roncancio
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depresión ,estudios fármaco ,económicos ,análisis costo ,efectividad ,ética ,Medical philosophy. Medical ethics ,R723-726 ,Ethics ,BJ1-1725 - Abstract
La depresión es uno de los más comunes y más serios problemas de la salud mental que se presenta hoy en día. Los análisis económicos en salud se han convertido en una herramienta fundamental para la toma de decisiones en políticas en salud y en procurar mayor bienestar a las personas, por lo que deben ser evaluados y aplicados de la mejor forma.
- Published
- 2008
13. Nuevas aportaciones sobre la Iglesia en la villa de Manzanilla durante el s. XVII y la devoción a Ntra. Sra. del Valle y Ntra. Sra. de la Victoria
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Germán Calderón Alonso
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History (General) ,D1-2009 ,Religion (General) ,BL1-50 - Abstract
Estudio sobre la religiosidad popular en la España de la Edad Moderna utilizando la documentación referente a la villa de Manzanilla (Sevilla), incidiendo en la importancia de las cofradías asentadas en la localidad.
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- 2000
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14. Dispositivo para medir tiempo y temperatura usando un microcontrolador
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Germán Calderón, José Herman Muñoz, and Javier Yovany Rivera
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Data acquisition system ,Sensor ,Microcontroller ,Physics ,QC1-999 - Abstract
En este trabajo se desarrolló un dispositivo de adquisición de datos, de bajo costo y fácil manejo, para usar en experimentos de física donde se requiera medir tiempo o temperatura, conformado por tres equipos principales: (i) Sensores para medir las variables físicas de tiempo y temperatura; (ii) Una tarjeta de adquisición con microcontrolador para el manejo de instrucciones y (iii) Una computadora para el almacenamiento de datos. El sensor, compuesto de un infrarrojo y un fototransistor, cambia su estado lógico al interrumpir la señal. La tarjeta que se utiliza incluye un microcontrolador de la marca Microchip, PIC18F14K50, el cual contiene comparadores, convertidores de análogo a digital, temporizadores y puerto de comunicación USB (Universal Serial Bus). El computador se usó como una herramienta de almacenamiento de datos y visualización de variables a través de una hoja de cálculo. La programación del microcontrolador se hizo con software MPLAB X de licencia gratuita. La funcionalidad del dispositivo se verificó en el experimento de caída libre para determinar el valor de la aceleración gravitacional.
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