Sample records for NUCLEOSIDOS (nucleosides)
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Sample records 1 - 20 shown. Select sample records:



1

Señales purinérgicas/ Purinergic signals

Lazarowski, Eduardo R; Schwarzbaum, Pablo J
2009-04-01

Resumen en español En la última década se ha aportado clara evidencia de que tanto nucleósidos como nucleótidos de adenina y uridina pueden funcionar como factores de señalización extracelular. Su acción es mediada por dos tipos principales de receptores de superficie denominados purinérgicos. Los receptores P1 se activan por adenosina, y son todos metabotrópicos, mientras que los receptores de nucleótidos (ATP, ADP, UTP y UDP) y nucleótidos-azúcares (UDP-glucosa y UDP-galactosa (mas) ) pueden ser metabotrópicos (P2Y) o ionotrópicos (P2X). La importancia y complejidad de este sistema de señalización se evidencia por la diversidad de mecanismos de liberación de nucleótidos al medio extracelular y por la distribución ubicua de varios grupos de ectonucleotidasas capaces de catalizar la degradación y conversión de nucleótidos. Hasta el momento se han descrito y clonado una veintena de estos receptores que modulan una variedad de respuestas, como el impulso nervioso, la respuesta inflamatoria, la secreción de insulina, la regulación del tono vascular y la percepción del dolor. En la presente revisión se describen las características estructurales y farmacológicas de los receptores purinérgicos y se analiza la interacción dinámica entre estos receptores, los nucleósidos y nucleótidos, y las ectonucleotidasas, con especial atención a la dinámica de la agregación plaquetaria, la respuesta inmune y la hidratación de las mucosas respiratorias. Resumen en inglés In the last decade evidence accumulated that nucleosides and nucleotides of both uridine and adenine can act as extracellular signaling factors. Their action is mediated by two main types of surface receptors commonly known as purinergic. P1 receptors are metabotropic and activated by adenosine, whereas receptors for nucleotides (ATP, ADP, UTP and UDP) and nucleotide-sugars (UDP-glucose and UDP-galactose) can be either metabotropic (P2Y) or ionotropic (P2X). The importanc (mas) e and complexity of this signaling system is evidenced by various mechanisms of nucleotide release, as well as by the ibiquitous distribution of various types of ectonucleotidases which catalyze and convert extracellular nucleotides. Up to now about twenty receptors have been cloned and found to modulate the nerve impulse, inflammatory response, insuline secretion, the regulation of the vascular tone and nociception, among other processes. In the present review we describe the main structural and pharmacological features of purinergic receptors, and analyze how the dynamic interaction between these receptors, nucleotides and nucleosides, and ectonucleotidases modulate several biological responses. Particular focus is given to platelet aggregation and thrombus formation, the immune response and the hydration of the mucosal linings of the respiratory tract.

Scientific Electronic Library Online (Spanish)

2

Estudio de sensibilidad antiviral de Virus Herpes simplex en pacientes trasplantados/ Antiviral sensitivity of Herpes simplex virus in immunocompromised patients

Illán, H.; Jacob, N.; Maiolo, E.; Cisterna, D.; Schiavelli, R.; Freire, M.C.
2004-06-01

Resumen en español La resistencia de virus Herpes simplex (VHS) a Aciclovir (ACV) ocurre en aproximadamente un 5% de los pacientes inmunocomprometidos. El tratamiento con análogos de nucleósidos, provoca la aparición de cepas VHS-ACV resistentes (ACVr). El mecanismo responsable de la resistencia a ACV son las mutaciones en los genes que codifican las enzimas timidina quinasa y/o ADN- polimerasa. En un estudio de aislamientos clinicos de pacientes inmunodeficientes, se encontró que el 96 (mas) % de los VHS ACVr son debidos a una baja producción o ausencia de la enzima y un4% son cepas con alteración de la especificidad por el sustrato, casi no se obtuvieron cepas mutantes en la ADN-polimerasa (15). Los análogos de Pirofosfatos generan resistencia por mutación en el gen de la ADN-polimerasa. En este trabajo se presenta la metodología empleada para el estudio de los perfiles de sensibilidad a ACV y a Foscarnet (PFA) en una población de inmunosuprimidos. Se estudiaron 46 aislamientos de VHS en fibroblastos humanos, provenientes de muestras de trasplantados con lesiones vesiculares. De los 46 aislamientos, 26 resultaron VHS-1 y 20 VHS-2, tipificados por Inmunofluorescencia (IF) con anticuerpos monoclonales. Posteriormente se amplificaron y se les determinó su perfíl de sensibilidad en células Vero, utilizando 100 Dosis infectivas en cultivo de tejidos 50% (DICT50) de cada cepa viral y las drogas antivirales en diferentes concentraciones. La concentración inhibitoria 50%(CI50) se calculó a partir del porcentaje de inhibición del efecto citopático en función de la concentración de la droga. Ninguno de los aislamientos resultó resistente al PFA y solo dos de ellos, uno de VHS-1 y uno de VHS-2, fueron resistentesa ACV. Resumen en inglés The Herpes simplex Virus (HSV) resistance to acyclovir (ACV) occurs in a 5% of the inmunocompromised patients, approximately. The treatment with analogs of nucleosides, causes the appearance of resistent HSV-ACV stocks(ACVr) which can be produced by alteration in genes coding for the TK or the DNA-polymerase. A previous large-scale clinical study on ACVr HSV strains isolated from patients infected with human immunodeficiency virus indicated that 96 % of ACVr HSV mutants w (mas) ere low producers of, or deficient in, TK activity (TK-), with 4 % being TK mutants with an altered substrate specificity. No DNA Pol mutants were isolated. The pirophosphate analogs generate resistance in the gene of DNA-polymerase by mutation. In this paper we show the methodology used for the determination of sensibilite profiles to ACV and Phoscarnet (PFA) in a population of inmunocompromised patients. We analized 46 HSV strain from vesicular injuries of transplanted patients. All samples, were inoculated in human fibroblasts and the HSV isolates were identified by inmunofluorescence whith monoclonal antibodies. These strains were amplified and the profile of susceptibility determinated in Vero cells, using 100 tissue culture inhibition dosis 50(TCID50)of each Viral stock and the specific antiviral drugs in different concentrations. The cytopathic effect (CPE) was evaluated after 72hs. post infection. The 50% inhibitory concentration (CI50) was calculated from the percentage of inhibition of the ECP based on the concentration of the drug. From 46 isolations, 26 were HSV-1 and 20 were HSV-2. Two of them, one HSV-1 andone HSV-2, were resistant to ACV and none of the isolates were resistant to PFA.

Scientific Electronic Library Online (Spanish)

3

Infección hepática crónica por el virus de la hepatitis B: una revisión con énfasis en los aspectos terapéuticos/ Chronic hepatitis B virus infection: a review with emphasis on therapy

Agudelo Restrepo, Catalina; Alzate Torres, Isabel Cristina; Restrepo Gutiérrez, Juan Carlos
2009-03-01

Resumen en español A pesar de las campañas mundiales de vacunación y de los adultos inmunocompetentes que resuelven su enfermedad, se calcula que 400 millones de personas en todo el mundo están infectadas crónicamente con el virus de la hepatitis B (VHB). Colombia ha pasado a tener una prevalencia baja con un 2% de la población positiva para el antígeno de superficie de este virus (HBsAg); sin embargo, la prevalencia varía entre las distintas regiones. Los portadores de VHB tienen ma (mas) yor riesgo de desarrollar hepatitis crónica, cirrosis hepática (CH), falla hepática y carcinoma hepatocelular (CHC). El tratamiento de la infección crónica por el VHB busca frenar por completo la replicación viral e inducir la remisión del daño hepático antes de que se desarrolle CH o CHC. Actualmente la terapia farmacológica se hace, entre otros medicamentos, con interferón pegilado alfa 2a, lamivudina, adefovir y entecavir. Los pacientes con hepatitis aguda no necesitan tratamiento, aquellos con falla hepática fulminante se deben evaluar para trasplante y el tratamiento de la infección crónica se debe elegir según la gravedad y características de la enfermedad. El seguimiento de los pacientes con infección aguda por el VHB se debe hacer cada 1-3 meses para detectar la progresión hacia hepatitis crónica; para ese propósito se miden los niveles de aminotransferasas, bilirrubinas, tiempo de protrombina, albúmina sérica, α-fetoproteína y ADN VHB; también se hacen recuento de plaquetas, biopsia hepática, ultrasonido abdominal y endoscopia digestiva superior. A los pacientes en tratamiento con interferón pegilado se les deben medir cada seis meses el antígeno e (HBeAg), su correspondiente anticuerpo (anti-HBe) y el ADN VHB. En quienes reciben lamivudina, adefovir, entecavir u otros antivirales, estas mediciones se hacen cada 3-6 meses. Se están estudiando otros fármacos con propiedades antivirales o inmunomoduladoras tales como: emtricitabine, clevudine, tenofovir, telmivudina y βL nucleósidos. Las estrategias inmunomoduladoras incluyen el uso de citoquinas y la vacunación. Resumen en inglés Despite vaccination campaigns around the world and the resolution of the disease in immunocompetent adults, it is estimated that 400 million people worldwide are chronically infected with the hepatitis B virus (HBV). The prevalence rate of this disease in the Colombian population is low, though variable among regions: only 2% are positive in tests for the surface antigen of this virus (HBsAg). Carriers of HBV have a higher risk of developing chronic hepatitis, cirrhosis ( (mas) HC), liver failure and hepatocellular carcinoma (HCC). The aims of treatment for chronic HBV infection are to completely control viral replication and to induce remission of liver damage before HC or HCC may develop. Nowadays, pharmacological therapy of HBV infection is done, among others, with pegylated interferon alfa 2a, lamivudine, adefovir, and entecavir. Patients with acute hepatitis do not need to be treated, those with acute liver failure should be evaluated for transplantation, and therapy for chronic infection should be chosen according to the degree of severity and the characteristics of their disease. Patients with acute HBV infection should be monitored every 1 to 3 months in order to detect the progression toward chronic hepatitis; for that purpose the levels of aminotransferases, bilirubin, prothrombin time, serum albumin, α-fetoprotein and HBV DNA are determined, and platelet count, liver biopsy, abdominal ultrasonography and upper digestive endoscopy are carried out. In patients being treated with alfa 2a pegylated interferon HBeAg, anti-HBe and HBV DNA must be measured every 6 months. These measurements should be made every 3 to 6 months in patients who use lamivudine, adefovir, entecavir or other antivirals. Other drugs with immunomodulatory or antiviral properties are being studied. The new antiviral agents include: emtricitabine, clevudine, tenofovir, telmivudine and β L nucleosides. Immunomodulatory strategies include the use of cytokines and vaccination.

Scientific Electronic Library Online (Spanish)

4

Intramolecular Cation-π Interactions As the Driving Force To Restrict the Conformation of Certain Nucleosides

Casanova, Elena; Priego, Eva M.; Jimeno, M. Luisa; Aguado, Leire; Negri, Ana; Gago, Federico; Camarasa, Mª Jose; Pérez Pérez, Mª Jesús
2009-01-01

Digital.CSIC (Spain)

5

Topology of evolving, mutagenized viral populations: quasispecies expansion, compression, and operation of negative selection

Ojosnegros Martos, Samuel; Agudo, Rubén; Sierra García, Macarena; Briones, Carlos; Sierra, Saleta; González-López, Claudia; Domingo, Esteban; Cristina, Juan
2008-07-17

Digital.CSIC (Spain)

7

Thermus thermophilus Strains Active in Purine Nucleoside Syntesis

Almendros, Marcos; Sinisterra Gago, Jose-Vicente; Berenguer, José

Digital.CSIC (Spain)

8

The use of conformationally rigid nucleoside probes to study the role of sugar pucker and nucleobase orientation in the thrombin binding aptamer

Saneyoshi, Hisao; Mazzini, Stefania; Aviñó, Anna; Portella, Guillem; González, Carlos; Orozco, Modesto; Márquez, Víctor E.; Eritja Casadellà, Ramón
2009-09-27

Digital.CSIC (Spain)

9

T4 RNA ligase catalyzes the synthesis of dinucleoside polyphosphates

Atencia, Eva Ana; Madrid, Olga; Günther Sillero, María A.; Sillero, Antonio
1999-05-01

Digital.CSIC (Spain)

10

Synthesis, stability, and protonation studies of a self-complementary dodecamer containing the modified nucleoside 2'-deoxyzebularine

Vives Blázquez, Montse; Eritja Casadellà, Ramón; Márquez, V. E.; Gargallo, Raimundo
2004-01-01

Digital.CSIC (Spain)

11

Synthesis of novel Bi-, Tri-, and tetracyclic nucleosides by reaction of a common cyclic enamine derived from TSAO-T with nucleophiles

Bonache, María-Cruz; Chamorro, Cristina; Cordeiro, Alessandra; Camarasa, María-José; Jimeno, M. Luisa; San-Félix, Ana
2004-01-01

Digital.CSIC (Spain)

12

Synthesis of mono- and bis-C-glycosylated 2,3,4-trisubstituted 1H-pyrroles as cyclo- and acyclo-C-nucleoside analogues

Alonso-Cruz, Carmen R.; Freire, Raimundo; Rodríguez, María S.; Suárez, Ernesto

5 pages, 1 table, 3 schemes. | A new method for the synthesis of mono- and bis-C-glycosylated 2,3,4-trisubstituted 1H-pyrroles, a type of cyclo- and ­acyclo-C-nucleoside analogues, is described. The reaction of readily available sensitive 2H-azirines derived from carbohydrates with 1,3-dicarbonyl co...

DRIVER (Spanish)

13

Synthesis of mono- and bis-C-glycosylated 2,3,4-trisubstituted 1H-pyrroles as cyclo- and acyclo-C-nucleoside analogues

Alonso-Cruz, Carmen R.; Freire, Raimundo; Rodríguez Morales, María S.; Suárez, Ernesto
2007-09-25

Digital.CSIC (Spain)

15

Synthesis and structural characterization of pyrimidine bi- and tricyclic nucleosides with sugar puckers conformationally locked into the eastern region of the pseudorotational cycle

Chamorro, Cristina; Luengo, Santos M.; Bonache, María Cruz; Velázquez, Sonsoles; Pérez Pérez, María Jesús; Camarasa, María José; Gago, Federico; Jimeno, M. Luisa; San Félix, Ana
2003-01-01

Digital.CSIC (Spain)

18

Second generation" of TSAO compounds directed against HIV-1 TSAO-resistant strains

Lobaton, E.; Velazquez, S.; Perez-Perez, M. J.; Jimeno, M. Luisa; San-Felix, S.; De Clercq, E.; Balzarini, J.; Camarasa, M. J.
2001-01-01

Digital.CSIC (Spain)

19

Role of a dipeptide insertion between codons 69 and 70 of HIV-1 reverse transcriptase in the mechanism of AZT resistance

Mas, Antonio; Parera, Mariona; Briones, Carlos; Soriano, Vicente; Martínez, Miguel Angel; Domingo, Esteban; Menéndez-Arias, Luis
2000-01-01

Digital.CSIC (Spain)

20

Plant nucleotide-sugar pyrophosphatase/phosphodiesterase (NPPASE), method of obtaining same and use of same in the production of assay devices and in the production of transgenic plants

Muñoz Pérez, Francisco José; Rodríguez López, Milagros; Baroja Fernández, Miren Edurne; Pozueta Romero Sánchez, Javier; Mitsui, Toshiaki; Nanjo, Yohei
2005-06-01

Digital.CSIC (Spain)

22

One-pot synthesis of azanucleosides from proline derivatives

Boto, Alicia; Hernández, Dácil; Hernández, Rosendo
2008-01-14

Digital.CSIC (Spain)

23

One-pot synthesis of acyclic nucleosides from carbohydrate derivatives, by combination of tandem and sequential reactions

Boto, Alicia; Hernández, Dácil; Hernández, Rosendo; Álvarez, Eleuterio

10 pages, 5 tables, 6 schemes.-- PMID: 17985924 [PubMed].-- Printed version published Dec 7, 2007. | Supporting information available at: http://pubs.acs.org/doi/suppl/10.1021/jo701608p | [Synthesis and spectroscopic data of starting materials 10-13, the acyclic nucleosides 24-28, 31-37, 40-47, 49, ...

DRIVER (Spanish)

25

One-Pot Synthesis of Polycyclic Nucleosides with Unusual Molecular Skeletons

Bonache, Maria-Cruz; Cordeiro, Alessandra; Carrero, Paula; Quesada, Ernesto; Camarasa, Mª Jose; Jimeno, M. Luisa; San-Félix, Ana
2009-01-01

Digital.CSIC (Spain)

26

New structural and functional defects in polyphosphate deficient bacteria: A cellular and proteomic study

Varela, Cristian; Mauriaca, Cecilia; Paradela, Alberto; Albar, Juan Pablo; Jerez, Carlos A.; Chávez, Francisco P.
2010-01-12

Digital.CSIC (Spain)

28

Insertions and Deletions in HIV-1 Reverse Transcriptase: Consequences for Drug Resistance and Viral Fitness

Menéndez-Arias, Luis; Matamoros Grande, Tania; Cases-González, Clara E.
2006-01-01

Digital.CSIC (Spain)

30

HIV-1 specific reverse transcriptase inhibitors: Why are TSAO-nucleosides so unique?

Camarasa, Mª José; San-Felix, Alejandra; Perez-Perez, María Jesús; Velazquez, Sonsoles; Alvarez, Rosa; Chamorro, Cristina; Jimeno, M. Luisa; Perez, Carlos; Gago, Federico; De Clercq, Erik; Balzarini, Jan
2000-01-01

Digital.CSIC (Spain)

32

Detection of DNA Adducts Derived from the Reactive Metabolite of Furan cis-2-Butene-1,4-dia

Byrns, Michael C.; Vu, Choua C.; Neidigh, Jonathan W.; Abad, José Luis; Jones, Roger A.; Peterson, Lisa A.
2006-02-28

Digital.CSIC (Spain)

34

DNA (Cytosine-C5) methyltransferase inhibition by oligodeoxyribonucleotides containing 2-(1H)-pyrimidinone (zebularine aglycon) at the enzymatic target site

Van Bemmel, Dana M.; Brank, Adam S.; Eritja Casadellà, Ramón; Márquez, Víctor E.; Christman, Judith K.
2009-05-23

Digital.CSIC (Spain)

36

Conformationally rigid nucleoside probes help understand the role of sugar pucker and nucleobase orientation in the thrombin-binding aptamer

Saneyoshi, Hisao; Mazzini, Stefania; Aviñó, Anna; Portella, Guillem; González, Carlos; Orozco, Modesto; Márquez, Víctor E.; Eritja Casadellà, Ramón
2009-07-20

Digital.CSIC (Spain)

38

Astrocytes are very sensitive to develop innate immune responses to lipid-carried short interfering RNA

Gorina, Roser; Santalucía, Tomàs; Petegnief, Valerie; Ejarque-Ortiz, Aroa; Saura, Josep; Planas, Anna M.
2009-01-01

Digital.CSIC (Spain)

40

3-(Aminomethyl)-2-(carboxymethyl)isoxazolidinyl nucleosides: building blocks for peptide nucleic acid analogues

Merino, Pedro; Tejero, Tomás; Matés, Juan; Chiacchio, Ugo; Corsaro, Antonio; Romeo, Giovanni
2007-06-17

Digital.CSIC (Spain)