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2.
Clin Exp Immunol ; 187(1): 146-159, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27613250

RESUMEN

A highly concentrated (20%) immunoglobulin (Ig)G preparation for subcutaneous administration (IGSC 20%), would offer a new option for antibody replacement therapy in patients with primary immunodeficiency diseases (PIDD). The efficacy, safety, tolerability and pharmacokinetics of IGSC 20% were evaluated in a prospective trial in Europe in 49 patients with PIDD aged 2-67 years. Over a median of 358 days, patients received 2349 IGSC 20% infusions at monthly doses equivalent to those administered for previous intravenous or subcutaneous IgG treatment. The rate of validated acute bacterial infections (VASBIs) was significantly lower than 1 per year (0·022/patient-year, P < 0·0001); the rate of all infections was 4·38/patient-year. Median trough IgG concentrations were ≥ 8 g/l. There was no serious adverse event (AE) deemed related to IGSC 20% treatment; related non-serious AEs occurred at a rate of 0·101 event/infusion. The incidence of local related AEs was 0·069 event/infusion (0·036 event/infusion, when excluding a 13-year-old patient who reported 79 of 162 total related local AEs). The incidence of related systemic AEs was 0·032 event/infusion. Most related AEs were mild, none were severe. For 64·6% of patients and in 94·8% of IGSC 20% infusions, no local related AE occurred. The median infusion duration was 0·95 (range = 0·3-4·1) h using mainly one to two administration sites [median = 2 sites (range = 1-5)]. Almost all infusions (99·8%) were administered without interruption/stopping or rate reduction. These results demonstrate that IGSC 20% provides an effective and well-tolerated therapy for patients previously on intravenous or subcutaneous treatment, without the need for dose adjustment.


Asunto(s)
Inmunoglobulinas Intravenosas/uso terapéutico , Síndromes de Inmunodeficiencia/tratamiento farmacológico , Adolescente , Adulto , Anciano , Niño , Preescolar , Europa (Continente) , Femenino , Estudios de Seguimiento , Humanos , Inmunoglobulinas Intravenosas/administración & dosificación , Inmunoglobulinas Intravenosas/farmacocinética , Infusiones Subcutáneas , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Adulto Joven
3.
Haemophilia ; 21(2): 162-170, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25623166

RESUMEN

Acquired haemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies against human factor VIII (hFVIII). OBI-1 is an investigational, B-domain deleted, recombinant FVIII, porcine sequence, with low cross-reactivity to anti-hFVIII antibodies. Efficacy can be monitored with FVIII activity levels in addition to clinical assessments. This prospective, open label, phase 2/3 study was designed to evaluate the efficacy of OBI-1 treatment for bleeding episodes in subjects with AHA. After an initial dose of 200 U kg(-1) , OBI-1 was titrated to maintain target FVIII activity levels, in correlation with clinical assessments, throughout the treatment phase. All 28 subjects with AHA had a positive response to OBI-1 treatment 24 h after initiation despite inhibition of FVIII activity levels immediately after infusion in 10 subjects with baseline anti-porcine FVIII inhibitors. Control of the qualifying bleed was ultimately achieved in 24 of 28 subjects. No related serious adverse events, thrombotic events, allergic reactions or thrombocytopaenia occurred. The results of this study indicate that OBI-1 is safe and effective in treating bleeding episodes in subjects with AHA. The ability to safely and effectively titrate dosing based on FVIII activity levels in this study demonstrates that OBI-1 fulfils the unmet medical need to monitor the key coagulation parameter in AHA patients.


Asunto(s)
Factor VIII/uso terapéutico , Hemofilia A/tratamiento farmacológico , Proteínas Recombinantes/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Animales , Anticuerpos Neutralizantes , Autoanticuerpos/inmunología , Reacciones Cruzadas/inmunología , Factor VIII/administración & dosificación , Factor VIII/efectos adversos , Factor VIII/inmunología , Femenino , Hemofilia A/inmunología , Humanos , Masculino , Persona de Mediana Edad , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/efectos adversos , Proteínas Recombinantes/inmunología , Porcinos , Factores de Tiempo , Resultado del Tratamiento
4.
Ying Yong Sheng Tai Xue Bao ; 23(8): 2114-20, 2012 Aug.
Artículo en Chino | MEDLINE | ID: mdl-23189687

RESUMEN

Mangrove wetland is an important type of coastal wetlands, and also, an important sediment trap. Sediment is an essential medium for mangrove recruitment and development, which records the environmental history of mangrove wetlands and can be used for the analysis of material sources and the inference of the materials depositing process, being essential to the ecological restoration and conservation of mangrove. In this paper, surface sediment samples were collected along a hydrodynamic gradient in Gaoqiao, Zhanjiang Mangrove National Nature Reserve in 2011. The characteristics of the surface sediments were analyzed based on grain size analysis, and the prediction surfaces were generated by the geo-statistical methods with ArcGIS 9.2 software. A correlation analysis was also conducted on the sediment organic matter content and the mangrove community structure. In the study area, clay and silt dominated the sediment texture, and the mean content of sand, silt, and clay was (27.8 +/- 15.4)%, (40.3 +/- 15.4)%, and (32.1 +/- 11.4)%, respectively. The spatial gradient of the sediment characteristics was expressed in apparent interpolation raster. With increasing distance from the seawall, the sediment sand content increased, clay content decreased, and silt content was relatively stable at a certain level. There was a positive correlation between the contents of sediment organic matter and silt, and a negative correlation between the contents of sediment organic matter and sand. Much more sediment organic matter was located at the high tide area with weak tide energy. There existed apparent discrepancies in the characteristics of the surface sediments in different biotopes. The sediment characteristics had definite correlations with the community structure of mangroves, reflecting the complicated correlations between the hydrodynamic conditions and the mangroves.


Asunto(s)
Sedimentos Geológicos/química , Rhizophoraceae/crecimiento & desarrollo , Humedales , China , Sistemas de Información Geográfica , Océanos y Mares , Tamaño de la Partícula , Análisis Espacial
5.
Diabetes Metab ; 38(5): 393-402, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22742875

RESUMEN

Diabetic gastroparesis is a component of autonomic neuropathy, and is the most common manifestation of gastrointestinal neuropathy. Diabetes is responsible for about one quarter of gastroparesis. The upper gastrointestinal symptoms are often non-specific and dominated by nausea, vomiting, early satiety, fullness, bloating. We also have to look for diabetic gastroparesis in case of metabolic instability, such as postprandial hypoglycaemia. The pathophysiology of diabetic gastroparesis is complex, partly due to a vagus nerve damage, but also to changes in secretion of hormones such as motilin and ghrelin. A decrease in the stem cell factor (SCF), growth factor for cells of Cajal (gastric pacemaker), was found in subjects with diabetic gastroparesis. These abnormalities lead to an excessive relaxation in the corpus, a hypomotility of antrum, a desynchronization antrum-duodenum-pylorus, and finally an abnormal duodenal motility. The treatment of diabetic gastroparesis is based on diabetes control, and split meals by reducing the fiber content and fat from the diet. The antiemetic and prokinetic agents should be tested primarily in people with nausea and vomiting. Finally, after failure of conventional measures, the use of gastric neuromodulation is an effective alternative, with well-defined indications. Introduced in the 1970s, this technology works by applying electrical stimulation continues at the gastric antrum, particularly in patients whose gastric symptoms are refractory to other therapies. Its efficacy has been recently reported in different causes of gastroparesis, especially in diabetes. Gastric emptying based on gastric scintigraphy, gastrointestinal symptoms, biological markers of glycaemic control and quality of life are partly improved, but not normalized. Finally, a heavy nutritional care is sometimes necessary in the most severe forms. The enteral route should be preferred (nasojejunal and jejunostomy if possible efficiency). However, in case of failure especially in patients with small bowel neuropathy, the long-term parenteral nutrition is sometimes required.


Asunto(s)
Neuropatías Diabéticas/terapia , Terapia por Estimulación Eléctrica , Fármacos Gastrointestinales/uso terapéutico , Gastroparesia/terapia , Estómago/fisiopatología , Neuropatías Diabéticas/fisiopatología , Terapia por Estimulación Eléctrica/métodos , Femenino , Gastroparesia/fisiopatología , Humanos , Masculino , Náusea , Apoyo Nutricional , Vómitos
6.
Cell Death Differ ; 16(10): 1344-51, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19543238

RESUMEN

Netrin-1 was recently proposed to control tumorigenesis by inhibiting apoptosis induced by the dependence receptors DCC (Deleted in colorectal cancer) and UNC5H. Although the loss of these dependence receptors' expression has been described as a selective advantage for tumor growth and progression in numerous cancers, recent observations have shown that some tumors may use an alternative strategy to block dependence receptor-induced programmed cell death: the autocrine expression of netrin-1. This alternative strategy has been observed in a large fraction of aggressive breast cancers, neuroblastoma, pancreatic adenocarcinoma, and lung cancer. This observation is of potential interest regarding future targeted therapy, as in such cases interfering with the ability of netrin-1 to inhibit DCC or UNC5H-induced cell death is associated with apoptosis of netrin-1-expressing tumor cells in vitro, and with inhibition of tumor growth or metastasis in different animal tumor models. The understanding of the mechanism by which netrin-1 inhibits cell death is therefore of interest. Here, we show that netrin-1 triggers the multimerization of both DCC and UNC5H2 receptors, and that multimerization of the intracellular domain of DCC and UNC5H2 is the critical step to inhibit the proapoptotic effects of both of these receptors. Taking advantage of this property, we utilized a recombinant specific domain of DCC that (i) interacts with netrin-1 and (ii) inhibits netrin-1-induced multimerization, to trigger apoptosis in netrin-dependent tumor cells.


Asunto(s)
Apoptosis , Neoplasias/metabolismo , Factores de Crecimiento Nervioso/farmacología , Receptores de Superficie Celular/metabolismo , Proteínas Supresoras de Tumor/farmacología , Animales , Línea Celular , Pollos , Receptor DCC , Modelos Animales de Enfermedad , Humanos , Receptores de Netrina , Netrina-1 , Multimerización de Proteína/efectos de los fármacos , Proteínas Recombinantes/farmacología , Proteínas Supresoras de Tumor/metabolismo
7.
Phys Rev Lett ; 99(2): 022503, 2007 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-17678217

RESUMEN

The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from the fragmentation of secondary beams of (42,44)S at 39A MeV. The low 2(+) energy of (42)Si, 770(19) keV, together with the level schemes of (41,43)P, provides evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that (42)Si is best described as a well-deformed oblate rotor.

8.
Phys Rev Lett ; 96(23): 232501, 2006 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-16803374

RESUMEN

The reduced transition probabilities B(E2;0(+) --> 2(+)(1)) of the neutron-rich (74)Zn and (70)Ni nuclei have been measured by Coulomb excitation in a (208)Pb target at intermediate energy. These nuclei have been produced at Grand Accélérateur National d'Ions Lourds via interactions of a 60A MeV (76)Ge beam with a Be target. The B(E2) value for (70)Ni(42) is unexpectedly large, which indicates that neutrons added above N=40 strongly polarize the Z=28 proton core. In the Zn isotopic chain, the steep rise of B(E2) values beyond N=40 continues up to (74)Zn(44). The enhanced proton core polarization in (70)Ni is attributed to the monopole interaction between the neutron in the g(9/2) and protons in the f(7/2) and f(5/2) spin-orbit partner orbitals. This interaction could result in a weakening of magicity in (78)Ni(50).

9.
Hum Mol Genet ; 15(6): 999-1013, 2006 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-16461336

RESUMEN

A nonsense mutation c.4250T>A (p.Leu1417X) in the dystrophin gene of a patient with an intermediate phenotype of muscular dystrophy induces partial in-frame skipping of exon 31. On the basis of UV cross-linking assays and pull-down analysis, we present evidence that the skipping of this exon is because of the creation of an exonic splicing silencer, which acts as a highly specific binding site (UAGACA) for a known repressor protein, hnRNP A1. Recombinant hnRNP A1 represses exon inclusion both in vitro and in vivo upon transient transfection of C2C12 cells with Duchenne muscular dystrophy (DMD) minigenes carrying the c.4250T>A mutation. Furthermore, we identified a downstream splicing enhancer in the central region of exon 31. This region functions as a Tra2beta-dependent exonic splicing enhancer (ESE) in vitro when inserted into a heterologous splicing reporter, and deletion of the ESE showed that incorporation of exon 31 depends on the Tra2beta-dependent enhancer both in the wild-type and mutant context. We conclude that dystrophin exon 31 contains juxtaposed sequence motifs that collaborate to regulate exon usage. This is the first elucidation of the molecular mechanism leading to exon skipping in the dystrophin gene and allowing the occurrence of a milder phenotype than the expected DMD phenotype. The knowledge of which cis-acting sequence within an exon is important for its definition will be essential for the alternative gene therapy approaches based on modulation of splicing to bypass DMD-causing mutations in the endogenous dystrophin gene.


Asunto(s)
Codón sin Sentido , Distrofina/genética , Exones/genética , Empalme del ARN/genética , Secuencias de Aminoácidos/genética , Secuencia de Bases , Regulación hacia Abajo/genética , Distrofina/biosíntesis , Regulación de la Expresión Génica/fisiología , Células HeLa , Ribonucleoproteína Nuclear Heterogénea A1 , Ribonucleoproteína Heterogénea-Nuclear Grupo A-B/metabolismo , Humanos , Datos de Secuencia Molecular , Fenotipo , Unión Proteica/genética , Precursores del ARN/metabolismo , Proteínas Represoras/metabolismo , Eliminación de Secuencia/genética
10.
Phys Rev Lett ; 95(18): 182501, 2005 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-16383897

RESUMEN

The excitation energy of the lowest-energy superdeformed band in 196Pb is established using the techniques of time-correlated gamma-ray spectroscopy. Together with previous measurements on 192Pb and 194Pb, this result allows superdeformed excitation energies, binding energies, and two-proton and two-neutron separation energies to be studied systematically, providing stringent tests for current nuclear models. The results are examined for evidence of a "superdeformed shell gap."

11.
Mol Ecol ; 13(1): 231-6, 2004 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-14653803

RESUMEN

Phylogenetic studies comparing the Dipterocarpaceae and the Sarcolaenaceae, a tree family endemic to Madagascar, have shown that the Sarcolaenaceae share a common ancestor with Asian dipterocarps. This suggests that Asian dipterocarps drifted away from Madagascar with the India-Seychelles landmass and then dispersed through Asia. Although all dipterocarps examined so far have been found to be ectomycorrhizal, the ectomycorrhizal status of Sarcolaenaceae had not been investigated. Here we establish the ectomycorrhizal status of Sarcolaenaceae using histological and molecular methods. This indicates that the common ancestor of the Sarcolaenaceae and Asian dipterocarps was ectomycorrhizal, at least before the separation of the Madagascar-India landmass, 88 million years ago.


Asunto(s)
Ericales/genética , Magnoliopsida/genética , Micorrizas/genética , Filogenia , Simbiosis , Secuencia de Bases , ADN Mitocondrial/genética , Geografía , Técnicas Histológicas , Funciones de Verosimilitud , Madagascar , Magnoliopsida/anatomía & histología , Magnoliopsida/fisiología , Modelos Genéticos , Datos de Secuencia Molecular , Micorrizas/fisiología , Raíces de Plantas/anatomía & histología , Análisis de Secuencia de ADN
13.
Int J Food Microbiol ; 73(2-3): 219-37, 2002 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11934031

RESUMEN

The combined effects of temperature, pH and organic acids (lactic, acetic and propionic) on the growth kinetics of Listeria innocua ATCC 33090 were studied. First, a multiplicative model was built assuming independent effects of all environmental factors. Thus, the model was expanded by the inclusion of a novel term describing the effects of interactions on the growth/no growth limits. The proposed approach allows an accurate description of the boundary between growth and no growth of Listeria.


Asunto(s)
Listeria/crecimiento & desarrollo , Ácido Acético/farmacología , Microbiología de Alimentos , Concentración de Iones de Hidrógeno , Ácido Láctico/farmacología , Listeria monocytogenes/crecimiento & desarrollo , Modelos Biológicos , Propionatos/farmacología , Temperatura
14.
Phys Rev Lett ; 88(9): 092501, 2002 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-11863997

RESUMEN

The neutron-rich (66,68)Ni have been produced at GANIL via interactions of a 65.9A MeV 70Zn beam with a 58Ni target. Their reduced transition probability B(E2;0(+)(1)-->2+) has been measured for the first time by Coulomb excitation in a (208)Pb target at intermediate energy. The B(E2) value for (68)Ni(40) is unexpectedly small. An analysis in terms of large scale shell model calculations stresses the importance of proton core excitations to reproduce the B(E2) values and indicates the erosion of the N = 40 harmonic-oscillator subshell by neutron-pair scattering.

15.
Ann Biol Clin (Paris) ; 59(1): 33-9, 2001.
Artículo en Francés | MEDLINE | ID: mdl-11174098

RESUMEN

An increase in homocysteine, a sulphur amino acid, is nowdays considered as a risk factor for cardiovascular diseases, and is independent of other risk factors. Reference range for total plasma homocysteine level in adults is usually 5-15 mmol/l. Hyperhomocysteinemia is defined as a fasting total plasma homocysteine level > 15 mmol/l. There may be also graded increased risks for subjects with homocysteinemia from 10 to 15 mmol/l. However, no threshold has been defined, partly because of the lack of standardization in pre-analytical and analytical steps. The aim of the present work was to evaluate three pre-analytical parameters on plasma homocysteine levels: i) the influence of three anticoagulants (EDTA, sodium citrate and lithium heparin); ii) the delay period of blood sample on ice before centrifugation; and iii) the advantages of strong acidic citrate at room temperature. The mean concentrations of total plasma homocysteine were different in function of the anticoagulant. These differences (EDTA minus lithium heparin or EDTA minus sodium citrate) were less than 10% however the used methods and could explain the good correlation between the results. However we recommend to keep the anticoagulant constant in the same study. When EDTA blood samples were immediately put on crushed ice, the maximum delay period before centrifugation could reach 4 hours. If ice is unavailable, strong acidic citrate at room temperature is a good alternative until for 4 hours.


Asunto(s)
Homocisteína/sangre , Anticoagulantes/farmacología , Centrifugación , Ácido Cítrico , Criopreservación , Homocisteína/efectos de los fármacos , Humanos , Temperatura , Factores de Tiempo
16.
Theriogenology ; 54(6): 907-19, 2000 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-11097044

RESUMEN

The aims of this study were to evaluate the effects of cooling rate to 4 degrees C and temperature at the time of centrifugation/glycerol-addition (freezing extender: INRA82 + 2% egg yolk + 2.5% glycerol) on postcentrifugation recovery rate, post-thaw motility and per-cycle fertility. When centrifugation/glycerol-addition was performed at 4 degrees C (14 ejaculates), a moderate cooling rate (37 degrees C to 4 degrees C in I h) resulted in higher post-thaw motility (45%) than when using a slow cooling rate (37 degrees C to 4 degrees C in 4 h) (39%; P<0.05). When centrifugation/glycerol-addition was performed at 22 degrees C (37 degrees C to 22 degrees C in 10 min) (10 ejaculates), post-thaw motility was lower when spermatozoa were frozen directly from 22 degrees C (23%) than when spermatozoa were cooled to 4 degrees C (22 degrees C to 4 degrees C in 1 h) before freezing (47%; P<0.0001). When centrifugation/glycerol-addition was performed at 22 degrees C (before cooling at a moderate rate), as opposed to 4 degrees C (after cooling at a moderate rate), a significant improvement of 1) recovery of spermatozoa after centrifugation (P<0,0001), 2) post-thaw motility of spermatozoa at thawing (40% vs 36% (n < or = 291 ejaculates/group), P<0.0001) and 3) per-cycle fertility (56% vs 42% (n > or = 190 cycles/group), P<0.01) was observed. In conclusion, centrifugation/glycerol-addition at 22 degrees C followed by cooling to 4 degrees C at a moderate rate results in an improvement of post-thaw motility, spermatozoa recovery rate and per cycle fertility.


Asunto(s)
Criopreservación/veterinaria , Crioprotectores/farmacología , Glicerol/farmacología , Caballos/fisiología , Preservación de Semen/veterinaria , Espermatozoides/fisiología , Animales , Centrifugación/veterinaria , Criopreservación/métodos , Femenino , Fertilidad , Masculino , Embarazo , Preservación de Semen/métodos , Motilidad Espermática/fisiología , Temperatura
17.
Mol Cell Biol ; 20(17): 6287-99, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10938105

RESUMEN

Splicing of the K-SAM alternative exon of the fibroblast growth factor receptor 2 gene is heavily dependent on the U-rich sequence IAS1 lying immediately downstream from its 5' splice site. We show that IAS1 can activate the use of several heterologous 5' splice sites in vitro. Addition of the RNA-binding protein TIA-1 to splicing extracts preferentially enhances the use of 5' splice sites linked to IAS1. TIA-1 can provoke a switch to use of such sites on pre-mRNAs with competing 5' splice sites, only one of which is adjacent to IAS1. Using a combination of UV cross-linking and specific immunoprecipitation steps, we show that TIA-1 binds to IAS1 in cell extracts. This binding is stronger if IAS1 is adjacent to a 5' splice site and is U1 snRNP dependent. Overexpression of TIA-1 in cultured cells activates K-SAM exon splicing in an IAS1-dependent manner. If IAS1 is replaced with a bacteriophage MS2 operator, splicing of the K-SAM exon can no longer be activated by TIA-1. Splicing can, however, be activated by a TIA-1-MS2 coat protein fusion, provided that the operator is close to the 5' splice site. Our results identify TIA-1 as a novel splicing regulator, which acts by binding to intron sequences immediately downstream from a 5' splice site in a U1 snRNP-dependent fashion. TIA-1 is distantly related to the yeast U1 snRNP protein Nam8p, and the functional similarities between the two proteins are discussed.


Asunto(s)
Proteínas de la Membrana/metabolismo , Proteínas , Empalme del ARN , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas Nucleares Pequeñas , Proteínas de Saccharomyces cerevisiae , Animales , Secuencia de Bases , Línea Celular , ADN Complementario/metabolismo , Exones , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Biblioteca de Genes , Células HeLa , Humanos , Intrones , Proteínas de la Membrana/química , Ratones , Modelos Genéticos , Datos de Secuencia Molecular , Plásmidos , Proteínas de Unión a Poli(A) , Pruebas de Precipitina , Unión Proteica , Estructura Terciaria de Proteína , Proteínas de Unión al ARN/química , Ratas , Proteínas Tirosina Quinasas Receptoras/genética , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos , Receptores de Factores de Crecimiento de Fibroblastos/genética , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Ribonucleoproteína Nuclear Pequeña U1/metabolismo , Antígeno Intracelular 1 de las Células T , Transfección , Rayos Ultravioleta
18.
Eur J Cell Biol ; 79(7): 488-94, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10961448

RESUMEN

In the developing chicken embryo, active DNA demethylation requires both RNA and proteins (Nucleic Acids Res. 25, 2375-2380, 1997; ibid. 25, 4545-4550, 1997, FEBS Lett. 449, 251-254, 1999a). In vitro assays indicate that in the 5- and 12-day-old embryos the highest specific activity of 5-methylcytosine DNA glycosylase is found in the brain, the eyes and the skin. In situ hybridization with antisense CpG-rich RNA tightly associated to the DNA demethylation complex shows a restricted expression pattern only in proliferating tissues such as the neuroepithelia of the brain in 5-day-old embryos. The RNA is absent in differentiated tissues like the skeletal and heart muscle, liver and the crystallin-producing cells in the lens. The CpG-rich RNA is transcribed in a developmental stage-specific rather than in a cell-specific manner. In contrast transcripts of DNA methyltransferase are found in dividing and quiescent cells. In situ hybridization with a probe of a RNA helicase which is also associated with the DNA demethylation complex shows a very similar localization in mitotically active tissues as the CpG-rich RNA. The content of 5-methylcytosine in individual cells was determined with a specific monoclonal antibody and cytometric analysis on tissue sections. The results indicate that proliferating cells have on the average 15% more methylated cytosines than non-dividing cells. This represents roughly 3x10(6) more methylation sites per haploid genome.


Asunto(s)
Islas de CpG , ADN Glicosilasas , Metilación de ADN , N-Glicosil Hidrolasas/biosíntesis , ARN Helicasas/biosíntesis , Animales , Encéfalo/metabolismo , Bromodesoxiuridina/metabolismo , División Celular , Embrión de Pollo , Pollos , Regulación hacia Abajo , Ojo/metabolismo , Inmunohistoquímica , Hibridación in Situ , Microscopía Fluorescente , Mitosis , N-Glicosil Hidrolasas/metabolismo , Hibridación de Ácido Nucleico , ARN Helicasas/metabolismo , ARN Mensajero/metabolismo , Piel/metabolismo , Factores de Tiempo , Distribución Tisular
19.
Proc Natl Acad Sci U S A ; 97(11): 5717-22, 2000 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-10823932

RESUMEN

RNA-binding motif (RBM) genes are found on all mammalian Y chromosomes and are implicated in spermatogenesis. Within human germ cells, RBM protein shows a similar nuclear distribution to components of the pre-mRNA splicing machinery. To address the function of RBM, we have used protein-protein interaction assays to test for possible physical interactions between these proteins. We find that RBM protein directly interacts with members of the SR family of splicing factors and, in addition, strongly interacts with itself. We have mapped the protein domains responsible for mediating these interactions and expressed the mouse RBM interaction region as a bacterial fusion protein. This fusion protein can pull-down several functionally active SR protein species from cell extracts. Depletion and add-back experiments indicate that these SR proteins are the only splicing factors bound by RBM which are required for the splicing of a panel of pre-mRNAs. Our results suggest that RBM protein is an evolutionarily conserved mammalian splicing regulator which operates as a germ cell-specific cofactor for more ubiquitously expressed pre-mRNA splicing activators.


Asunto(s)
Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Proteínas de Unión al ARN/metabolismo , Animales , Núcleo Celular/metabolismo , Células Germinativas/metabolismo , Humanos , Infertilidad Masculina/metabolismo , Masculino , Ratones , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Precursores del ARN/metabolismo , Empalme del ARN , Proteínas de Unión al ARN/genética , Proteínas Recombinantes de Fusión/metabolismo , Factores de Empalme Serina-Arginina , Especificidad por Sustrato , Técnicas del Sistema de Dos Híbridos
20.
Nat Immunol ; 1(1): 47-53, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10881174

RESUMEN

We studied the influence of memory T cell properties on the efficiency of secondary immune responses by comparing the in vivo immune response of the same numbers of T cell receptor (TCR) transgenic (Tg) naïve and memory T cells. Compared to naïve Tg cells, memory cells divided after a shorter lag time; had an increased division rate; a lower loss rate; and showed more rapid and efficient differentiation to effector functions. We found that initial naïve T cell priming resulted in cells expressing mutually exclusive effector functions, whereas memory T cells were multifunctional after reactivation, with each individual cell expressing two to three different effector functions simultaneously. These special properties of memory T cells ensure the immediate control of reinfection.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Animales , Antígenos CD8/inmunología , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/inmunología , Reordenamiento Génico de Linfocito T/inmunología , Memoria Inmunológica , Ratones , Ratones Transgénicos , Receptores de Antígenos de Linfocitos T/genética
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