RESUMEN
Second generation sequencing has revolutionized genomic studies. However, most genomes contain repeated DNA elements that are longer than the read lengths achievable with typical sequencers, so the genomic order of several generated contigs cannot be easily resolved. A new generation of sequencers offering substantially longer reads is emerging, notably the Pacific Biosciences (PacBio) RS II system and the MinION system, released in early 2014 by Oxford Nanopore Technologies through an early access program. The latter has highly advantageous portability and sequences samples by measuring changes in ionic current when single-stranded DNA molecules are translocated through nanopores. We show that the MinION system produces long reads with high mapability that can be used for scaffolding bacterial genomes, despite currently producing substantially higher error rates than PacBio reads. With further development we anticipate that MinION will be useful not only for assembling genomes, but also for rapid detection of organisms, potentially in the field.
Asunto(s)
Bacterias/genética , ADN Bacteriano/química , Genoma Bacteriano , Nanoporos , Análisis de Secuencia de ADN/métodos , Biblioteca de Genes , Secuenciación de Nucleótidos de Alto Rendimiento , Alineación de SecuenciaRESUMEN
We review the different modes of meiosis and its deviations encountered in polyploid animals. Bisexual reproduction involving normal meiosis occurs in some allopolyploid frogs with variable degrees of polyploidy. Aberrant modes of bisexual reproduction include gynogenesis, where a sperm stimulates the egg to develop. The sperm may enter the egg but there is no fertilization and syngamy. In hybridogenesis, a genome is eliminated to produce haploid or diploid eggs or sperm. Ploidy can be elevated by fertilization with a haploid sperm in meiotic hybridogenesis, which elevates the ploidy of hybrid offspring such that they produce diploid gametes. Polyploids are then produced in the next generation. In kleptogenesis, females acquire full or partial genomes from their partners. In pre-equalizing hybrid meiosis, one genome is transmitted in the Mendelian fashion, while the other is transmitted clonally. Parthenogenetic animals have a very wide range of mechanisms for restoring or maintaining the mother's ploidy level, including gamete duplication, terminal fusion, central fusion, fusion of the first polar nucleus with the product of the first division, and premeiotic duplication followed by a normal meiosis. In apomictic parthenogenesis, meiosis is replaced by what is effectively mitotic cell division. The above modes have different evolutionary consequences, which are discussed. See also the sister article by Grandont et al. in this themed issue.
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Cromosomas/genética , Meiosis , Poliploidía , Anfibios/genética , Animales , Núcleo Celular/genética , Intercambio Genético , Evolución Molecular , Femenino , Fertilización , Hibridación Genética , Masculino , Mitosis , Región Organizadora del Nucléolo/genética , PartenogénesisRESUMEN
We demonstrate a concurrent polarization-retrieval algorithm based on a multi-heterodyne scanning near-field optical microscopy (MH-SNOM) measurement system. This method relies on calibration of the polarization properties of the MH-SNOM using an isotropic region of the sample in the vicinity of the nanostructures of interest. We experimentally show the effectiveness of the method on a silicon form-birefringent grating (FBG) with significant polarization diversity. Three spatial dimensional near-field measurements are in agreement with theoretical predictions obtained with rigorous coupled-wave analysis (RCWA). Pseudo-far-field measurements are performed to obtain the effective refractive index of the FBG, emphasizing the validity of the proposed method. This reconstruction algorithm makes the MH-SNOM a powerful tool to analyze concurrently the polarization-dependent near-field optical response of nanostructures with sub wavelength resolution as long as a calibration area is available in close proximity.
Asunto(s)
Algoritmos , Microscopía de Fuerza Atómica/instrumentación , Microscopía Confocal/instrumentación , Refractometría/instrumentación , Birrefringencia , Diseño de Equipo , Análisis de Falla de Equipo , Microscopía de Fuerza Atómica/métodos , Microscopía Confocal/métodosRESUMEN
We demonstrate guided-mode resonance filters featuring an amorphous TiO(2) layer fabricated by atomic layer deposition on a polymeric substrate. The thermal properties of such filters are studied in detail by taking into account both thermal expansion of the structure and thermo-optic coefficients of the materials. We show both theoretically and experimentally that these two effects partially compensate for each other, leading to nearly athermal devices. The wavelength shift of the resonance reflectance peak (< 1 nm) is a small fraction of the peak width (~11 nm) up to temperatures exceeding the room temperature by tens of degrees centigrade.
Asunto(s)
Filtración/instrumentación , Polímeros/química , Refractometría/instrumentación , Resonancia por Plasmón de Superficie/instrumentación , Titanio/química , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de EquipoRESUMEN
We demonstrate good optical quality TiO(2) thin films grown by atomic layer deposition at 120 degrees C. The optical properties were studied using spectroscopic ellipsometry and prism coupling methods. The refractive index was 2.27, and the slab waveguide propagation loss was less than 1dB/cm at 1.53microm. A high quality resonant waveguide grating was fabricated using a thin TiO(2) layer on top of a SiO(2) grating.
RESUMEN
Effect of angled sidewalls on the filling and properties of silicon slot waveguides is discussed. We demonstrate complete filling of slot waveguide structures with oxide material systems using the atomic layer deposition technique and discuss use of various slot filling materials. Properties of the optical modes in angled-sidewall slot waveguides are studied. Enhanced vertical confinement is obtained with certain waveguide parameters. The reduced effective mode area enhances e.g. nonlinear effects in the waveguide. We discuss the use of atomic layer deposition in realization of filled slot waveguides optimized for all-optical functionalities.
RESUMEN
Coeliac disease (CD) is becoming a model for understanding the pathogenesis of autoimmune disorders. In CD, antibodies against transglutaminase 2 (TG2) and specific residues of gliadins have been identified. A similar situation is seen in rheumatoid arthritis (RA) with both anti-citrullinated protein antibodies (ACPA) and auto-antibodies against the citrullinating enzyme, peptidylarginine deiminase (PAD). Previously, we have suggested that a complex between an enzyme and its modified substrate constitutes the neoantigen in autoimmune diseases. Our hypothesis is challenged by findings in patients of primary Sjögren's syndrome (pSS) who do not express ACPA, but who have been reported to carry anti-PAD. The aims of our investigation were to reproduce the study claiming the presence of anti-PAD in pSS and screen for ACPA and antibodies against TG2 and PAD in pSS (n = 78), multiple sclerosis (MS) (n = 85) and Alzheimer's disease (AD) (n = 79) using ELISA. With blood donors (n = 100) as controls, no increased occurrence of autoantibodies was found among the patient groups tested. Contrary to what has been published previously, patients with pSS do not express anti-PAD. The hypothesis of a complex between an enzyme and its modified substrate constituting the neoantigen in autoimmune diseases is still valid. The prevalence of anti-PAD, anti-TG2 and ACPA is comparatively restricted. PAD and TG2 do not seem to be involved directly in autoimmune mechanisms in pSS, MS or AD.
Asunto(s)
Enfermedad de Alzheimer/sangre , Autoanticuerpos/sangre , Enfermedades Autoinmunes/fisiopatología , Citrulina/inmunología , Proteínas de Unión al GTP/inmunología , Hidrolasas/inmunología , Esclerosis Múltiple/sangre , Síndrome de Sjögren/sangre , Transglutaminasas/inmunología , Enfermedades Autoinmunes/sangre , Citrulina/metabolismo , Ensayo de Inmunoadsorción Enzimática , Humanos , Proteína Glutamina Gamma Glutamiltransferasa 2 , Desiminasas de la Arginina Proteica , Proteínas/metabolismoRESUMEN
Chronic immune stimulation such as Helicobacter pylori (hp) infection, Sjögren's syndrome or coeliac disease may initiate non-Hodgkin lymphoma (NHL). The opposite (appearance of autoimmunity) has also been reported. The aim of this study was to describe the pattern of these immune markers in patients with lymphoid malignancies. Sera from 96 patients with NHL (median age 72, range 38-88, F/M 41/55) were analysed with ELISA to determine the frequency of antibodies against guinea pig (gp) and human recombinant (hr) transglutaminase type 2 (Tg2), and hr factor XIII subunit a* (part of the Tg-family), extractable nuclear antigen (ENA), and hp. As hp antibodies decrease in younger age cohorts a sex- and age-matched control group of 768 persons was used. The control population for transglutaminase antibodies consisted of 59 blood donors, (median 42 years, range 19-65) was analysed with a commercial kit. Gp-Tg2-IgG positivity was documented in 72% and hr-Tg2-IgG positivity in 15% (5% positive controls for both; P < 0.001 and ns, respectively). For IgA 3% had gp-Tg2 and 4% hr-Tg2 (5% in controls: ns for both). Anti-FXIII-IgA positivity was found in 22% (5% in controls; P = 0.03). Unspecific anti-ENA-IgG positivity was found in 24% (P < 0.001), while only 2% had specific ENA autoantibodies. Moreover, 36% were positive for anti-hp-IgG, while controls were positive in 54% (P < 0.001). The frequency of unspecific autoantibodies was increased. No differences could be noted in specific autoantibodies (hr-Tg2-IgA). In contrast, fewer than expected were anti-hp-positive. A defective immune response, similar to that in autoimmune diseases, could contribute to the pathogenesis of lymphoid malignancies.
Asunto(s)
Anticuerpos/sangre , Linfoma no Hodgkin/sangre , Adulto , Anciano , Anciano de 80 o más Años , Animales , Anticuerpos/inmunología , Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/inmunología , Especificidad de Anticuerpos , Antígenos Nucleares/inmunología , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Biomarcadores/sangre , Ensayo de Inmunoadsorción Enzimática , Factor XIII/inmunología , Femenino , Cobayas/inmunología , Helicobacter pylori/inmunología , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina A/inmunología , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Subunidades de Proteína/inmunología , Proteínas Recombinantes/inmunología , Transglutaminasas/inmunologíaRESUMEN
OBJECTIVE: The findings of the involvement of tissue transglutaminase (tTg) in the pathogenesis of coeliac disease (CD) have stimulated progress in the field of auto-immune diseases. Another calcium-dependent cysteine enzyme, peptidylarginine deiminase type 4 (PAD4), seems to be involved in the pathogenesis of rheumatoid arthritis (RA). There are obvious similarities between Tgs and PADs. METHODS: Using enzyme-linked immuno-sorbent assays, we have measured the occurrence of antibodies against guinea pig (gp) and human recombinant (hr) tTg, PAD and citrulline in 59 controls and 184 RA-patients, of whom 71 were treated with methotrexate (mtx). RESULTS: In addition to the expected antibodies against citrulline (62%), sera from the 113 RA-patients without mtx treatment contained significantly increased frequencies of IgG anti-PAD (35%), IgA anti-gp-tTg (34%), IgA anti-hr tTg (20%), IgG anti-gp-tTg (13%) and IgA anti-hr-FXIII (15%) compared to controls. In sera from the mtx-treated RA-patients the expression of antibodies was reduced. In patients not treated with methotrexate there was a statistically significant correlation between, on one hand, IgG anti-PAD and on the other hand, IgG anti-citrulline, IgA anti-gp-tTg, IgA anti-hr-tTg, IgG anti-gp-tTg, IgG anti-hr-tTg, or IgA anti-hr-FXIII. In the mtx-treated group these correlations were less pronounced. CONCLUSION: In addition to the expected antibodies against citrulline, sera from RA-patients contained antibodies against PAD and against Tgs of at least two kinds, indicating that the specificity for anti-tTg in CD is far from complete. Most of the patients displayed more than one antibody, a possible indication of epitope spreading. MTX-treatment reduced the expression of antibodies.
Asunto(s)
Artritis Reumatoide/inmunología , Autoanticuerpos/sangre , Citrulina/inmunología , Epítopos/inmunología , Hidrolasas/inmunología , Transglutaminasas/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Animales , Antirreumáticos/uso terapéutico , Artritis Reumatoide/sangre , Artritis Reumatoide/tratamiento farmacológico , Autoanticuerpos/inmunología , Femenino , Cobayas , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina A/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Masculino , Metotrexato/uso terapéutico , Persona de Mediana Edad , Desiminasas de la Arginina Proteica , Proteínas RecombinantesRESUMEN
The increased interest in asexual organisms calls for in-depth studies of asexual complexes that actively give rise to new clones. We present an extensive molecular study of the Otiorhynchus scaber (Coleoptera, Curculionidae) weevil system. Three forms have traditionally been recognized: diploid sexuals, triploid, and tetraploid parthenogens. All forms coexist in a small central area, but only the polyploid parthenogens have colonized marginal areas. Analyzing the phylogenetic relationship, based on three partial mitochondrial genes, of 95 individuals from 19 populations, we find that parthenogenesis and polyploidy have originated at least three times from different diploid lineages. We observe two major mitochondrial lineages, with over 2.5% sequence divergence between the most basal groups within them, and find that current distribution and phylogenetic relationships are weakly correlated. Quite unexpectedly, we also discover diploid clones that coexist with, and are morphologically indistinguishable from, the diploid sexual females. Our results support that these diploid clones are derived directly from the diploid sexuals. We also find that it is mainly an increase in ploidy level and not the benefits of asexual reproduction that confers to polyploid parthenogens the advantage over their diploid sexual relatives.
Asunto(s)
Insectos/genética , Poliploidía , Reproducción Asexuada/genética , Animales , Femenino , Datos de Secuencia Molecular , Filogenia , Reproducción Asexuada/fisiologíaRESUMEN
PURPOSE: A new mucus-secreting in vitro drug absorption model based on monolayers of goblet-cell like sub-clones of the human colon carcinoma cell line HT29 obtained by methotrexate (MTX) treatment was investigated. METHODS: Twelve sub-clones were isolated and characterized by light microscopy (LM), transelectron microscopy (TEM), confocal laser scanning microscopy (CLSM), transepithelial electrical resistance (TEER) and the transport of a paracellular marker FITC-Dextran (Mw 4400) (FD-4). RESULTS: Significant differences of microscopical appearance, TEER-values and permeability of FD-4 between the sub-clones were evident. However, two of them, namely MTX-D1 and MTX-E12. formed tight confluent monolayers with a thick mucus-layer on the apical surface. They were used to compare the apparent permeability coefficient (Papp) of a series of lipophilic drugs, which should be affected by the mucus-layer, namely barbiturates (barbituric acid, barbital, phenobarbital, methylphenobarbital and heptabarbital) and testosterone, as a reference, to mucus-free Caco-2 cells. The permeability of drugs with a partition coefficient (log P) > 1 was decreased in the mucus-producing cell lines. Testosterone, the most lipophilic compound, showed a decrease of up to 43%. CONCLUSIONS: We demonstrated that the mucus layer is a significant barrier to drug absorption for lipophilic drugs. In conclusion, our model may serve as a suitable in-vitro cell culture model to study the influence of the mucus layer on drug diffusion.
Asunto(s)
Moco/fisiología , Preparaciones Farmacéuticas/metabolismo , Algoritmos , Barbitúricos/química , Barbitúricos/metabolismo , Transporte Biológico , Fenómenos Químicos , Química Física , Células Clonales , Difusión , Conductividad Eléctrica , Células Epiteliales/fisiología , Células HT29 , Humanos , Lípidos/química , Microscopía Confocal , Microscopía Electrónica , Mucinas/biosíntesis , Mucinas/genética , Moco/metabolismo , Preparaciones Farmacéuticas/química , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Solubilidad , Uniones Estrechas/metabolismoRESUMEN
We present an operational method for estimating the amount of PAR intercepted by a coniferous shoot. Interception of PAR by a shoot is divided into three components: the amount of radiation coming from the sky, the transmission of radiation through the surrounding vegetation, and the shoot' s silhouette area facing the direction of the incoming radiation. All three components usually vary with direction. Radiation incident from the sky consists of direct and diffuse radiation. The well-known equation of motion for the sun and Beer' s Law for atmospheric transmittance are used to simulate the directional distribution of direct sunlight for any given period of time. The diffuse component is assumed to be uniform. Meteorological field measurements are used to calibrate the absolute amounts of the direct and diffuse components. The gap fraction (proportion of visible sky) in different directions around a shoot is measured by analyzing a hemispherical fish-eye photograph, taken at the location of the shoot, with an image processing program. Similarly, the shoot silhouette area (SSA) is measured by photographing the shoot from many different directions. The measurements of SSA are interpolated by a method called trigonometric interpolation to obtain the directional distribution of SSA over the entire hemisphere. This distribution is then rotated according to the shoot' s position in the canopy. Multiplying incoming PAR, canopy gap fraction and SSA in different directions, and summing over all directions, gives an estimate of PAR intercepted by the shoot during the chosen period of time. The method is described step by step, and applied, as an example, to a shoot from a Scots pine (Pinus sylvestris L.) stand in central Finland. Differences in radiation interception properties between sun and shade shoots and their relevance to canopy-scale models are discussed.
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Cycadopsida/fisiología , Brotes de la Planta/fisiología , Árboles/fisiología , Luz , MatemáticaRESUMEN
We examined the effects of structural and physiological acclimation on the photosynthetic efficiency of Scots pine (Pinus sylvestris L.) shoots. We estimated daily light interception (DLI) and photosynthesis (DPHOT) of a number of sample shoots situated at different positions in the canopy. Photosynthetic efficiency (epsilon) was defined as the ratio of DPHOT to the potential daily light interception (DLI(ref)) defined as the photosynthetically active radiation (PAR) intercepted per unit area of a sphere at the shoot location. To calculate DLI(ref), DLI and DPHOT, the radiation field surrounding a shoot in the canopy was first modeled using simulated directional distributions of incoming PAR on a clear and an overcast day, and estimates of canopy gap fraction in different directions provided by hemispherical photographs. A model of shoot geometry and measured data on shoot structure and photosynthetic parameters were used to simulate the distribution of PAR irradiance on the needle surface area of the shoot. Photosynthetic efficiency (epsilon) was separated into light-interception efficiency (epsilon(I) = DLI/DLI(ref)) and conversion efficiency (epsilon(PHOT) = DPHOT/DLI). This allowed us to quantify separately the effect of structural acclimation on the efficiency of photosynthetic light capture (epsilon(l)), and the effect of physiological acclimation on conversion efficiency (epsilon(PHOT)). The value of epsilon increased from the top to the bottom of the canopy. The increase was largely explained by structural acclimation (higher epsilon(I)) of the shade shoots. The value of epsilon(PHOT) of shade foliage was similar to that of sun foliage. Given these efficiencies, the clear-day value of DPHOT for a sun shoot transferred to shade was only half that of a shade shoot at its original position. The method presented here provides a tool for quantitatively estimating the role of acclimation in total canopy photosynthesis.
Asunto(s)
Fotosíntesis/fisiología , Pinus/fisiología , Brotes de la Planta/fisiología , Árboles/fisiología , Luz , Matemática , Modelos Biológicos , Pinus/anatomía & histología , Hojas de la Planta/anatomía & histología , Hojas de la Planta/fisiología , Brotes de la Planta/anatomía & histología , Árboles/anatomía & histologíaRESUMEN
We have developed a spatially inexplicit model of canopy photosynthesis for balsam fir (Abies balsamea (L.) Mill.) that accounts for key processes of light-shoot interaction including irradiance interception by the shoot, spatial aggregation of shoots into branches and crowns, the differential propagation of diffuse and direct light within the canopy, and an ideal representation of penumbra. Also accounted for in the model are the effects of the average radiative climate and shoot age on needle retention, light interception, and photosynthetic capacity. We used reduced versions of this model to quantify the effects of simplifying canopy representation on modeled canopy net photosynthesis. Simplifications explored were the omission of direct beam transformation into penumbral light and the use of different constant shoot properties throughout the canopy. The model was parameterized for a relatively dense balsam fir stand (leaf area index of 5.8) north of Québec City, Canada, and run using hourly meteorological data obtained at the site. The overall performance of the complete model was satisfactory, with maximum values of canopy net photosynthesis of 23 micromol (m(2) ground)(-1) s(-1) (83 mmol m(-2) h(-1)), and a near-saturation of the canopy at a photosynthetically active radiation photon flux density of about 750 micromol m(-2) s(-1) (2.7 mol m(-2) h(-1)). The omission of penumbral effects through the use of unattenuated direct (beam) radiation at all layers of the canopy, as used for broad-leaved species, reduced canopy net photosynthesis by 3.7%. Analysis of the results show that the small impact of penumbra on canopy net photosynthesis stems from the high proportion of diffuse radiation (73%) estimated from our meteorological data set; single-hour results under clear sky conditions approach theoretical bias values of about 30%. Use of mean shoot photosynthetic, light capture and light transmission properties throughout the canopy biased canopy net photosynthesis by less than 3%. However, simulations carried out based on properties of 1-year-old shoots throughout the canopy overestimated canopy net photosynthesis by 9%. Use of the shoot as our smallest functional unit was a potential source of bias because the differential absorption of direct and diffuse radiation within the shoot could not be factored into the model. Other sources of potential bias are discussed.
Asunto(s)
Abies/fisiología , Modelos Biológicos , Fotosíntesis/fisiología , Hojas de la Planta/fisiología , Brotes de la Planta/anatomía & histología , Árboles/fisiología , Abies/anatomía & histología , Luz , Matemática , Hojas de la Planta/anatomía & histología , Brotes de la Planta/fisiología , Árboles/anatomía & histologíaRESUMEN
The aim of this study was to devise experimental protocols and computational models for the prediction of intestinal drug permeability. Both the required experimental and computational effort and the accuracy and quality of the resulting predictions were considered. In vitro intestinal Caco-2 cell monolayer permeabilities were determined both in a highly accurate experimental setting (Pc) and in a faster, but less accurate, mode (Papp). Computational models were built using four different principles for generation of molecular descriptors (atom counts, molecular mechanics calculations, fragmental, and quantum mechanics approaches) and were evaluated for their ability to predict intestinal membrane permeability. A theoretical deconvolution of the polar molecular surface area (PSA) was also performed to facilitate the interpretation of this composite descriptor and allow the calculation of PSA in a simplified and fast mode. The results indicate that it is possible to predict intestinal drug permeability from rather simple models with little or no loss of accuracy. A new, fast computational model, based on partitioned molecular surface areas, that predicts intestinal drug permeability with an accuracy comparable to that of time-consuming quantum mechanics calculations is presented.
Asunto(s)
Membrana Celular/fisiología , Absorción Intestinal , Mucosa Intestinal/fisiología , Transporte Biológico/efectos de los fármacos , Radioisótopos de Carbono , Línea Celular , Permeabilidad de la Membrana Celular , Ciprofloxacina/farmacocinética , Biología Computacional/métodos , Diseño de Fármacos , Foscarnet/farmacocinética , Humanos , Enlace de Hidrógeno , Absorción Intestinal/efectos de los fármacos , Lactulosa/farmacocinética , Manitol/farmacocinética , Modelos Biológicos , Rafinosa/farmacocinética , Propiedades de Superficie , Tritio , Verapamilo/farmacologíaAsunto(s)
Citometría de Flujo/métodos , Insectos/genética , Ploidias , Animales , Núcleo Celular/genética , Femenino , Masculino , Partenogénesis/genéticaRESUMEN
Neurotrophins promote multiple actions on neuronal cells including cell survival and differentiation. The best-studied neurotrophin, nerve growth factor (NGF), is a major survival factor in sympathetic and sensory neurons and promotes differentiation in a well-studied model system, PC12 cells. To mediate these actions, NGF binds to the TrkA receptor to trigger intracellular signaling cascades. Two kinases whose activities mediate these processes include the mitogen-activated protein (MAP) kinase (or extracellular signal-regulated kinase [ERK]) and phosphoinositide 3-kinase (PI3-K). To examine potential interactions between the ERK and PI3-K pathways, we studied the requirement of PI3-K for NGF activation of the ERK signaling cascade in dorsal root ganglion cells and PC12 cells. We show that PI3-K is required for TrkA internalization and participates in NGF signaling to ERKs via distinct actions on the small G proteins Ras and Rap1. In PC12 cells, NGF activates Ras and Rap1 to elicit the rapid and sustained activation of ERKs respectively. We show here that Rap1 activation requires both TrkA internalization and PI3-K, whereas Ras activation requires neither TrkA internalization nor PI3-K. Both inhibitors of PI3-K and inhibitors of endocytosis prevent GTP loading of Rap1 and block sustained ERK activation by NGF. PI3-K and endocytosis may also regulate ERK signaling at a second site downstream of Ras, since both rapid ERK activation and the Ras-dependent activation of the MAP kinase kinase kinase B-Raf are blocked by inhibition of either PI3-K or endocytosis. The results of this study suggest that PI3-K may be required for the signals initiated by TrkA internalization and demonstrate that specific endocytic events may distinguish ERK signaling via Rap1 and Ras.
Asunto(s)
Endocitosis , Factor de Crecimiento Nervioso/metabolismo , Fosfatidilinositol 3-Quinasas/fisiología , Transducción de Señal , Proteínas de Unión al GTP rap1/metabolismo , Proteínas ras/metabolismo , 1-Metil-3-Isobutilxantina/farmacología , Animales , Western Blotting , Diferenciación Celular , Supervivencia Celular , Células Cultivadas , Cromatografía de Afinidad , Cromonas/farmacología , Colforsina/farmacología , Relación Dosis-Respuesta a Droga , Activación Enzimática , Inhibidores Enzimáticos/farmacología , Flavonoides/farmacología , Ganglios Espinales/metabolismo , Inmunohistoquímica , Luciferasas/metabolismo , Microscopía Electrónica , Microscopía Fluorescente , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Modelos Biológicos , Morfolinas/farmacología , Células PC12 , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-raf/metabolismo , Ratas , Receptor trkA/metabolismo , Factores de Tiempo , TransfecciónRESUMEN
During the last 3 decades, large resources have been allocated through the organized dental care system for the improvement of dental health among children and teenagers in Sweden. The aim of this study was to describe attitudes related to dental health and dental care among 20 to 25-year-old Swedes. A random sample of 650 individuals was drawn from the database of the National Social Insurance Board of Sweden. A postal questionnaire comprising 70 questions was delivered to the subjects and the response rate was 78%. A high proportion of the respondents considered themselves to have a high need for dental care. They had a strong conception of being able to influence their own dental health. Quite a few were concerned about their dental health. A high proportion indicated that they were satisfied with their dental function, but fewer individuals were satisfied with the appearance of their teeth. The respondents also reported good reception by their dentists, although opinions differed between the sexes. Women reported a significantly higher degree of discomfort and unease than men. Most respondents had adopted good oral hygiene habits but dental floss was rarely used. The majority of subjects indicated that they attended dental examinations on an annual basis. There is a need for further investigation into patients' attitudes to dental health and dental care. It is important to understand the significance patients attach to different concepts in the dental treatment. This would enhance our understanding of how the concept of felt need is expressed and transformed into demand for care.
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Actitud Frente a la Salud , Salud Bucal , Adulto , Afecto , Distribución de Chi-Cuadrado , Atención Odontológica/psicología , Dispositivos para el Autocuidado Bucal , Relaciones Dentista-Paciente , Estética Dental , Femenino , Necesidades y Demandas de Servicios de Salud , Humanos , Masculino , Higiene Bucal , Dolor/psicología , Participación del Paciente , Satisfacción del Paciente , Autoimagen , Autoevaluación (Psicología) , Factores Sexuales , Encuestas y Cuestionarios , SueciaRESUMEN
Lead compounds generated in high throughput drug discovery programmes often have unfavorable biopharmaceutical properties, resulting in a low success rate of such drug candidates in clinical development. Drug companies and researchers would thus like to have methods of predicting biopharmaceutical properties accurately. The intestinal permeability to a lead compound is one such property which is particularly important. Therefore, access to methods to accurately predict biopharmaceutical properties, such as the intestinal permeability of a large series of compounds, is of particular importance. This review deals with new theoretical methods used to predict intestinal drug permeability. There are several possible transport routes across the intestine, but theoretical methods generally deal with only one of them, the passive transcellular route. Therefore, this review will also discuss the relative importance of passive and active drug transport and efflux routes using recent data generated in cell cultures, animal models and human subjects.
Asunto(s)
Biofarmacia , Absorción Intestinal , Animales , Transporte Biológico , Simulación por Computador , Diseño de Fármacos , Humanos , Modelos BiológicosRESUMEN
OBJECTIVE: The purpose of this study was to investigate the contribution of Abl kinase and phosphatidylinositol 3-kinase (PI3-kinase) to the altered adhesive properties and cytoskeletal defects in a Bcr-Abl transformed fibroblast cell model. MATERIALS ANID METHODS: Two fibroblast cell lines stably transfected with Bcr-Abl were compared to their parental counterparts for alterations in their adhesive properties in an attachment assay and for abnormalities in their cytoskeletal architecture by immunofluorescence microscopy. Cells then were treated with specific inhibitors of either the Abl kinase CGP57148 or the PI3-kinase LY294002 to determine whether these treatments would restore normal cytoarchitecture and adhesion. RESULTS: [corrected] Significant defects in cytoskeletal architecture were observed using this fibroblast model of Bcr-Abl expression. Specific changes include loss of stress fibers and focal adhesions, which correlated with an adhesive defect. [corrected] Treatment of Bcr-Abl expressing cells with CGP57148, but not LY294002, resulted in reversion of cells to a near-normal phenotype, as assessed by immunofluorescence and attachment of Bcr-Abl transformed fibroblasts. CONCLUSIONS: Our studies demonstrate that Bcr-Abl tyrosine kinase but not PI3- kinase activity is required for maintenance of cytoskeletal rearrangements resulting from Bcr-AbI expression. Further, inhibition of Abl kinase restored normal adhesive properties to the Bcr-Abl-expressing cells, demonstrating the contribution of Bcr-Abl kinase activity to abnormal cytoskeletal function.