RESUMEN
Semaphorins are multifunctional factors implicated in various developmental processes. Little is known about the intracellular pathways ensuring appropriate signal transduction that encode the diverse functions observed. In this study, we investigated whether mitogen-activated protein kinases (MAPK), which are key elements of signal transduction in eukaryotic cells, were activated during semaphorin 3A (Sema3A)-induced repulsion or apoptosis of neural progenitor cells. We found that selective recruitment of the ERK1/2 pathway occurred during Sema3A-induced neural progenitor cell repulsion, whereas p38 MAPK activation was necessary for induction of apoptosis. Moreover, we provide evidence for the involvement of vascular endothelial growth factor receptor 1 (VEGFR1) in the activation of ERK1/2. Additional experiments performed with native cerebellar progenitors confirmed such a selective recruitment of MAPK during Sema3A-dependent migration or apoptosis. Altogether, our results suggest a model to explain how a single factor can exert different functions for a given cell type by the selective recruitment of intracellular pathways.
Asunto(s)
Apoptosis/fisiología , Sistema de Señalización de MAP Quinasas/fisiología , Neuronas/enzimología , Semaforina-3A/metabolismo , Células Madre/enzimología , Animales , Apoptosis/efectos de los fármacos , Comunicación Celular/efectos de los fármacos , Comunicación Celular/fisiología , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Movimiento Celular/fisiología , Activación Enzimática/efectos de los fármacos , Activación Enzimática/fisiología , Inhibidores Enzimáticos/farmacología , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Ratones , Proteína Quinasa 3 Activada por Mitógenos , Proteínas Quinasas Activadas por Mitógenos/efectos de los fármacos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Sistema Nervioso/citología , Sistema Nervioso/embriología , Sistema Nervioso/enzimología , Neuronas/citología , Semaforina-3A/farmacología , Células Madre/citología , Células Madre/efectos de los fármacos , Receptor 1 de Factores de Crecimiento Endotelial Vascular/efectos de los fármacos , Receptor 1 de Factores de Crecimiento Endotelial Vascular/metabolismo , Proteínas Quinasas p38 Activadas por MitógenosRESUMEN
The HMG-domain transcription factor Sox10 is essential for the development of various neural crest derived lineages including glia and neurons of the peripheral nervous system (PNS). Within the PNS the most striking defect is the complete absence of glial differentiation whereas neurogenesis seemed initially normal. A degeneration of motoneurons and sensory neurons occurred later in development. The mechanism that leads to the dramatic effects on the neural crest derived cell lineages in the dorsal root ganglia (DRG), however, has not been examined up to now. Here, we provide a detailed analysis of proliferation and apoptosis in the DRG during the time of their generation and lineage segregation (between E 9.5 and E 11.5). We show that both increased apoptosis as well as decreased proliferation of neural crest cells contribute to the observed hypomorphism.
Asunto(s)
Proteínas de Unión al ADN/fisiología , Ganglios Espinales/embriología , Ganglios Espinales/metabolismo , Proteínas del Grupo de Alta Movilidad/química , Proteínas del Grupo de Alta Movilidad/fisiología , Sistema Nervioso Periférico/embriología , Apoptosis , Diferenciación Celular , División Celular , Linaje de la Célula , Proteínas de Unión al ADN/genética , Marcadores Genéticos , Heterocigoto , Proteínas del Grupo de Alta Movilidad/genética , Homocigoto , Inmunohistoquímica , Hibridación in Situ , Operón Lac , Microscopía Fluorescente , Cresta Neural/citología , Estructura Terciaria de Proteína , Factores de Transcripción SOXE , Factores de Tiempo , Factores de TranscripciónRESUMEN
Normal and jimpy oligodendrocytes in secondary cultures were transfected with plasmids containing the SV40 T-antigen gene expressed under the control of the mouse metallothionein-I promoter. Two immortalized stable cell lines, a normal (158N) and jimpy (158JP) cell line, expressed transcripts and proteins of oligodendrocyte markers, including proteolipid protein (PLP), myelin basic protein (MBP), and carbonic anhydrase II (CAII). Galactocerebroside and sulfatide were also detected with immunocytochemistry. Immunoelectron microscopy using gold particles showed that the truncated endogenous jimpy PLP was distributed throughout the cytoplasm and in association with the plasma membrane of cell bodies and processes. The length of the cell cycle in the jimpy oligodendrocytes in the absence of zinc was 31 h, about a 4-h longer cell cycle than the normal line. In the presence of 100 microM zinc, the cell cycle became 3 h shorter for both cell lines, with the jimpy cell cycle duration remaining 4 h longer than the normal line. Interestingly, the jimpy cell line showed a significant deficiency in stimulation via the cAMP pathway. While the level of oligodendrocyte markers (PLP, MBP, and CAII) were significantly increased by dibutyryl cAMP (dbcAMP) treatment in the normal cell line, no changes were observed in the jimpy cell lines. This observation, together with previous results showing jimpy oligodendrocyte's failure to respond to basic fibroblast growth factor (bFGF), suggests a role for PLP in a signal transduction pathway. Jimpy and normal oligodendrocytes transfected with the SV40T antigen gene, driven by the wild-type promoter of mouse metallothionein-I, continue to express properties of oligodendrocytes and therefore provide a powerful model to explore the function of myelin proteins and to dissect the complexity of the jimpy phenotype.
Asunto(s)
AMP Cíclico/metabolismo , Ratones Jimpy/fisiología , Proteína Proteolipídica de la Mielina/genética , Proteínas del Tejido Nervioso , Oligodendroglía/citología , Oligodendroglía/metabolismo , Animales , Antígenos Virales de Tumores/metabolismo , Biomarcadores , Bromodesoxiuridina/metabolismo , Bucladesina/farmacología , Ciclo Celular , División Celular , Línea Celular Transformada , Células Cultivadas , Inmunohistoquímica , Ratones , Microscopía Electrónica , Neuronas/citología , Neuronas/fisiología , Oligodendroglía/efectos de los fármacos , Oligodendroglía/ultraestructura , ARN Mensajero/metabolismo , Valores de Referencia , Distribución TisularRESUMEN
We have examined the ultrastructural aspect of neuronal precursors derived from 14-day-old rat embryos during their development under various culture conditions. Cells maintained in serum-free medium which have developed for 1 week in vitro present ultrastructural features of young neurons. They contain many free ribosomes and microtubules, but few other organelles and incompletely developed Golgi apparatus. In the presence of basic fibroblast growth factor (bFGF), besides cells remaining in aggregates and displaying morphological features of undifferentiated cells, dispersed neuroblasts underwent accelerated ultrastructural maturation. They present well-developed Golgi apparatus, axodendritic synapses and dense-core vesicles already after 3 days in culture. By contrast, in the presence of astroglial-conditioned medium a more homogeneous population developed showing ultrastructural features of relatively mature neurons. However, the neuronal precursors acquired the most mature ultrastructural aspect when they were cocultured with astroglial cells. The neuronal cell bodies contain highly developed Golgi complexes, well-differentiated ergastoplasm and Niss1 body formations, while in the complex neurite network much more numerous mature synapses with clear and dense-core vesicles are visible. These observations indicate that a combination of soluble factors and membrane-bound factors is essential for extensive ultrastructural development of neuronal precursors in vitro. Another finding was that in these cultured neurons neurofilaments (NF) were never seen, while NF protein subunits were found. These data suggest that the polymerization of the three NF subunits into intermediate filaments might need particular cellular factors which probably do not exist under our in vitro conditions.
Asunto(s)
Astrocitos/fisiología , Corteza Cerebral/embriología , Factor 2 de Crecimiento de Fibroblastos/farmacología , Neuronas/ultraestructura , Animales , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Corteza Cerebral/citología , Técnicas de Cocultivo , Medios de Cultivo Condicionados/farmacología , Aparato de Golgi/ultraestructura , Proteínas de Neurofilamentos/metabolismo , Orgánulos/ultraestructura , Ratas , Médula Espinal/metabolismo , Médula Espinal/ultraestructuraRESUMEN
The C1G5F2 antigen is a newly described minor myelin antigen of the central nervous system. Its expression compared with that of some other main myelin protein components (Wolfgram W1 protein, myelin basic proteins (MBP) and proteolipids) was investigated in rat oligodendrocytes derived from 10-day-old primary glial cell cultures and subcultured for several days in a chemically defined medium. It was demonstrated immunocytochemically that this antigen is detected later than the major myelin markers. All cells immunoreactive with the monoclonal antibody C1G5F2 were always labeled either by W1-, MBP- or proteolipid-specific antisera. It was also shown at the electron microscopic level that this antigen is mainly expressed on the surface of the extremities of the fine oligodendroglial processes. All these observations suggest that the C1G5F2 antigen may be a useful marker for a specific step in the oligodendrocyte maturation stage.
Asunto(s)
Glicoproteínas de Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Oligodendroglía/inmunología , Animales , Glicoproteínas de Membrana/ultraestructura , Proteínas de la Mielina/metabolismo , Proteínas del Tejido Nervioso/ultraestructura , Oligodendroglía/ultraestructura , RatasRESUMEN
Apoptosis, also known as programmed cell death, is a mechanism used by different tissues to regulate their cell content. In the nervous system, this process is supposed to adjust the final number of neurons to the number of the target cells they are innervating. The demonstration that, in several systems in vitro and in vivo, neuronal apoptosis can be prevented by inhibiting RNA or protein synthesis suggests that an activation of gene expression is required in the cells that are going to die. The genes involved and their products, named "killer proteins," are not known in the superior vertebrates. In order to identify such proteins, we have used and characterized an in vitro model consisting of neurons derived from 8-day-old embryonic chicken ciliary ganglia. RNA and protein synthesis inhibitors can prevent the death of these neurons when they are deprived of trophic support. Comparing the synthesis of proteins in trophic-supported neurons with that in trophic-deprived neurons by the use of two-dimensional polyacrylamide gel electrophoresis, we have observed that several proteins were overexpressed reproducibly in the apoptotic cells. We found that all these proteins are localized in the nucleus, suggesting that they may be transcription regulators.
Asunto(s)
Apoptosis/fisiología , Factor 2 de Crecimiento de Fibroblastos/farmacología , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/farmacología , Neuronas/fisiología , Animales , Anisomicina/farmacología , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Embrión de Pollo , Medios de Cultivo , Cicloheximida/farmacología , Dactinomicina/farmacología , Factor 2 de Crecimiento de Fibroblastos/administración & dosificación , Ganglios Parasimpáticos/citología , Cinética , Microscopía Electrónica , Factores de Crecimiento Nervioso , Proteínas del Tejido Nervioso/administración & dosificaciónRESUMEN
It is generally accepted that the action of thyroid hormones is mediated through specific nuclear receptors. Recent studies have demonstrated the homology of the thyroid receptor with the cellular product of the oncogen v-erbA. So far, two genes have been identified and classified as alpha and beta subtypes. In this study, the expression of nuclear triiodothyronine (T3) receptors (NT3Rs) was examined in secondary cultures containing 85-90% oligodendrocytes (OL) prepared from newborn rat brain primary cultures enriched in OL. These cultures, which are able to produce myelin membranes, were examined by double immunolabelling with a monoclonal antibody (2B3) raised against purified rat liver NT3Rs and with antibodies against two maturation markers of OL: an early marker, galactocerebroside (GC), and myelin basic protein (MBP), which is expressed later than GC. 2B3 recognized three nuclear proteins with the same molecular weights as beta 1, alpha 1, and alpha 2 subtypes with different capacities for binding T3. In 5-day-old OL secondary cultures (25 days, total time in culture), 2B3-NT3R immunoreactivity was located in 77% of morphologically immature OL (GC)+ cells, whereas only 44% of morphologically mature OL were immunoreactive. Only 35% of the MBP+ cells co-expressed NT3Rs. In the corpus callosum of developing rat brain, at all ages studied from 7-60 days postnatal, the total absence of NT3Rs in dark OL (morphologically mature), confirmed by ultrastructural immunocytochemistry, indicates an even more dramatic decrease during maturation. Furthermore, the percentage of medium OL (less mature) stained by 2B3 is reduced by approximately half in 60- compared to 20-day-old rat brain. It is of interest to note that the in vitro observation with maturation markers mirrors the in vivo decrease of NT3R expression during development. It is interesting that NT3Rs are absent in vivo before the critical period of active myelination. These data indicate the presence of a nuclear T3 binding protein in the nuclei of OL at the time of myelination both in vitro and in vivo. The transient expression of these NT3Rs during active myelination argues in favour of a direct effect of thyroid hormones on OL.
Asunto(s)
Oligodendroglía/metabolismo , Receptores Citoplasmáticos y Nucleares/biosíntesis , Receptores de Hormona Tiroidea/biosíntesis , Animales , Animales Recién Nacidos , Anticuerpos Monoclonales/inmunología , Encéfalo/citología , Química Encefálica/fisiología , Proteína Ácida Fibrilar de la Glía/inmunología , Proteína Ácida Fibrilar de la Glía/metabolismo , Inmunohistoquímica , Microscopía Inmunoelectrónica , Proteínas Nucleares/inmunología , Proteínas Nucleares/metabolismo , Oligodendroglía/ultraestructura , Ratas , Receptores Citoplasmáticos y Nucleares/inmunología , Receptores de Hormona Tiroidea/inmunologíaRESUMEN
To explore the behaviour of microtubule-associated proteins, MAP2 and TAU in the interactions of mitochondria with microtubules, an homologous acellular system has been reconstituted with organelles isolated from rat brain. We have established a quantitative in vitro binding assay based on the cosedimentation of 125I-labeled microtubules with mitochondria. We found that binding of microtubules to mitochondria was concentration dependent and saturable. Binding was insensitive to ATP. A comparison of taxol-stabilized microtubules prepared from MAP-free tubulin or tubulin coated with TAU or MAP2 showed that the microtubule-associated proteins diminished, or reduced to background levels, the formation of complexes with mitochondria. In contrast, the amount of MAP-free taxol microtubules that cosedimented with mitochondria increased two- and six-fold when mitochondria were coated with MAP2 or TAU. These studies suggest that the two major brain MAPs could have a crosslinking or a spacing role, depending on their organelle localization.
Asunto(s)
Encéfalo/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Microtúbulos/metabolismo , Mitocondrias/metabolismo , Tubulina (Proteína)/metabolismo , Proteínas tau/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Química Encefálica , Sistema Libre de Células , Microtúbulos/efectos de los fármacos , Paclitaxel/farmacología , Ratas , Ratas Wistar , Tubulina (Proteína)/aislamiento & purificaciónRESUMEN
It is generally accepted that thyroid hormones act at the genomic level through an interaction with specific nuclear receptors. Using a monoclonal antibody raised against the rat liver nuclear L-T3 receptor (NTR), we report here the immunocytochemical localization of T3 receptors in the adult rat brain. The strongest NTR immunoreactivity was found in the olfactory bulb, the hippocampus, the dentate gyrus, the amygdala areas, and the neocortex (layers III-VI). An intermediate NTR immunoreactivity was found in the hypothalamus, whereas the thalamus, the caudate-putamen, and the pallidum were weakly NTR-immunoreactive. In the cerebellum, a strong NTR immunoreactivity was found in the nuclei of Purkinje cells, in the internal granular layer, and in some nuclei of cells located in the molecular layer. In the brainstem, a strong NTR immunoreactivity was found in the lateral mamillary nucleus and the interstitial nucleus. A weak to moderate NTR immunoreactivity was observed in the central gray matter, while the substantia nigra and the interpeduncular nucleus were weakly stained. Furthermore, we also found NTR immunoreactivity in the nuclei of ependymocytes, epithelial cells of the choroid plexus, and cells located in the white matter. At the electron microscope level, we confirm that the immunoreactivity was not only localized in the nuclei of neurons but also in the nuclei of astrocytes and medium oligodendrocytes. This study provides new information concerning the distribution of NTR in the rat brain: (1) NTR are present not only in neurons but also in glial and ependymal cells, and (2) there is a regional and cellular heterogeneity in the distribution of NTR in the central nervous system.
Asunto(s)
Química Encefálica , Encéfalo/ultraestructura , Receptores de Hormona Tiroidea/análisis , Animales , Anticuerpos Monoclonales , Encéfalo/citología , Tronco Encefálico/química , Tronco Encefálico/citología , Tronco Encefálico/ultraestructura , Núcleos Cerebelosos/química , Núcleos Cerebelosos/citología , Núcleos Cerebelosos/ultraestructura , Plexo Coroideo/química , Plexo Coroideo/citología , Plexo Coroideo/ultraestructura , Hipocampo/química , Hipocampo/citología , Hipocampo/ultraestructura , Inmunohistoquímica , Masculino , Microscopía Electrónica , Bulbo Olfatorio/química , Bulbo Olfatorio/citología , Bulbo Olfatorio/ultraestructura , Células de Purkinje/química , Células de Purkinje/ultraestructura , Ratas , Ratas Endogámicas , Receptores de Hormona Tiroidea/ultraestructuraRESUMEN
It was revealed a positive correlation between an antioxidative potential (AP) of blood plasma from psoriasis patients and generation of O2- by normal granulocytes, stimulated by zymosan or aggregated human gamma-globulin, in the presence of the same plasma samples. The AP of plasma was measured by means of inhibition of the chemiluminescence arising during photoautoxidation of luminol. The production of O2- after cell stimulation was estimated by means of the reduction of tetrazolium salt. The result is discussed from the viewpoint of informative-regulatory role of the plasma AP for the white blood cells as a part of the whole organism, participating in its common defence reactions.
Asunto(s)
Antioxidantes/farmacocinética , Granulocitos/inmunología , Psoriasis/inmunología , Femenino , Radicales Libres , Humanos , Mediciones Luminiscentes , Masculino , Valores de ReferenciaRESUMEN
8 patients with confirmed psoriatic arthritis were treated with splenopentin for 12 months. A relief of joint pain could be detected under this treatment both after 6 weeks (improvement of the Ritchie-indices: 44%) and after 12 months (improvement: 28%). In contrast to this, X-ray investigations show a worsening of the disease after 12 months. Therefore we conclude that splenopentin alone is not a sufficient therapeutic drug in patients suffering from psoriatic arthritis.
Asunto(s)
Artritis Psoriásica/terapia , Fragmentos de Péptidos/administración & dosificación , Timopoyetinas/administración & dosificación , Hormonas del Timo/administración & dosificación , Adulto , Esquema de Medicación , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The effects of acidic and basic fibroblast growth factors (aFGF and bFGF) on the morphology of cultured rat astroblasts and on the expression of glial fibrillary acidic protein (GFAP) were compared. The addition of either aFGF or bFGF affected the morphology of the flat, irregular, polygonal-shaped astroblasts, which formed processes and acquire a fibrous appearance. Appreciable different morphological aspects were observed between aFGF- and bFGF-induced cells, essentially between 11 and 14 days in culture. In the presence of bFGF the astroglial cells were more fibrous with a more compact perikaryon as compared to aFGF treated cells. At the ultrastructural level abundant intermediate filaments were observed in astroglial cells as an effect of aFGF and rare filaments but numerous microtubules were seen in bFGF-treated cells. The immunoreactivity for GFAP increased with time in culture and was much stronger in aFGF-treated cells compared to bFGF-treated cells at day 14. An intense positive staining was observed in the somata of the astroglial cells and their processes in the presence of aFGF, while essentially the processes were stained in the presence of bFGF. After 21 days in culture GFAP immunoreaction was also found in the perikarya of cells treated with bFGF. These results show that rat astroglial cells respond somewhat differently to aFGF and bFGF.
Asunto(s)
Astrocitos/citología , Factores de Crecimiento de Fibroblastos/farmacología , Animales , Animales Recién Nacidos , Astrocitos/efectos de los fármacos , Astrocitos/ultraestructura , Encéfalo/citología , Células Cultivadas , Proteína Ácida Fibrilar de la Glía/análisis , Técnicas para Inmunoenzimas , Microscopía Electrónica , RatasRESUMEN
The distribution of fibroblast growth factor (FGF) at the ultrastructural level in the brain of young (15- and 20-day-old) and adult (3-month-old) rats was investigated by immunocytochemistry. Strong staining was observed in most neurons of the cortex of young rat brain. In the same brain area of adult rat many neurons were also stained intensely, while others were negative. Neurons in the other parts of the brain and especially in the adult rat, were generally more weakly stained. The reaction product was located in the cytoplasm of the neuronal cell bodies and their processes. Astrocytes, oligodendrocytes, microglial cells, meningeal cells, choroïd epithelial cells, ependymal cells and capillary endothelial cells showed no staining.
Asunto(s)
Corteza Cerebral/análisis , Factores de Crecimiento de Fibroblastos/análisis , Factores de Edad , Animales , Corteza Cerebral/ultraestructura , Técnicas para Inmunoenzimas , Inmunohistoquímica , Microscopía Electrónica , Ratas , Ratas EndogámicasRESUMEN
We have measured the extent of incorporation of zeaxanthin (C40) and decaprenozeaxanthin (C50) in unilamellar vesicles of dimyristoylphosphatidylcholine (n-C14) and dipalmitoylphosphatidylcholine (n-C16). The incorporation is larger when the molecular length of the carotenoid corresponds to the thickness of the phospholipid bilayer. Stereochemically pure 2,3-di-O-phytanyl-sn-glycero-1-phosphocholine was prepared by modification of the polar heads of the phospholipids of Halobacterium halobium. Vesicles of this branched-chain ether phospholipid incorporate poorly the carotenoids, whereas egg lecithin vesicles incorporate them better. Osmotic swelling and water permeability of vesicles, with or without carotenoids, were measured in a stopped-flow, light-scattering system. The reinforcing effect (lower permeability and higher rigidity) of carotenoids at 1.5 mol% incorporation into diphytanylphosphatidylcholine vesicles is comparable to that of 5 mol% cholesterol; however, carotenoids have no measurable effect on the egg lecithin vesicles. These results imply that the reinforcement of the membrane depends on a subtle adjustment of the phospholipid-carotenoid system.
Asunto(s)
Carotenoides/análogos & derivados , Carotenoides/metabolismo , Liposomas/metabolismo , Xantófilas , beta Caroteno/análogos & derivados , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , Carotenoides/farmacología , Permeabilidad de la Membrana Celular/efectos de los fármacos , Fenómenos Químicos , Química , Dimiristoilfosfatidilcolina/metabolismo , Técnica de Fractura por Congelación , Halobacterium/análisis , Luz , Membrana Dobles de Lípidos/metabolismo , Liposomas/farmacología , Microscopía Electrónica , Ósmosis/efectos de los fármacos , Fosfatidilcolinas/metabolismo , Dispersión de Radiación , Relación Estructura-Actividad , ZeaxantinasRESUMEN
Using a 0.075% 8-methoxypsoralen solution, minimal phototoxic doses and improvement of psoriasis lesions were investigated in 15 patients suffering from chronic stationary psoriasis. The time interval between topical 8-methoxypsoralen application and long-wave ultraviolet light irradiation was increased stepwise. The mean minimal phototoxic dose declined with increasing time interval and reached its minimum 2 h after 8-methoxypsoralen application. In spite of that, antipsoriatic efficiency was maximal 15 min after application. In order to obtain a favorable relationship between antipsoriatic efficiency and unwanted side effects when using topical PUVA treatment, irradiation should be started 15 min after 8-methoxypsoralen application.
Asunto(s)
Terapia PUVA/métodos , Psoriasis/tratamiento farmacológico , Adulto , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Humanos , Masculino , Persona de Mediana EdadAsunto(s)
Neoplasias Cutáneas/diagnóstico , Anciano , Enfermedad de Bowen/diagnóstico , Carcinoma Basocelular/diagnóstico , Carcinoma de Células Escamosas/diagnóstico , Diagnóstico Diferencial , Humanos , Melanoma/diagnóstico , Nevo Pigmentado/diagnóstico , Enfermedad de Paget Extramamaria/diagnóstico , Pronóstico , Neoplasias Cutáneas/cirugía , Verrugas/diagnósticoAsunto(s)
Alquitrán/uso terapéutico , Metoxaleno/uso terapéutico , Terapia PUVA/métodos , Fotoquimioterapia/métodos , Psoriasis/tratamiento farmacológico , Administración Tópica , Adulto , Anciano , Baños , Alquitrán/administración & dosificación , Femenino , Humanos , Masculino , Metoxaleno/administración & dosificación , Persona de Mediana EdadRESUMEN
Astroglial cells from cerebral hemispheres of newborn rats were cultured for 5 days in Waymouth's MD 705/1 medium containing 10% fetal calf serum. Thereafter, cells were grown in a chemically defined medium consisting of basal Waymouth's medium supplemented with insulin (5 µg/ml) and fatty acid free bovine serum albumin (0.5 mg/ml). The cells underwent morphological and biochemical development over a period of 28 days. The changes in the amount of glial fibrillary acidic protein indicated a development of gliofilaments. The level of S100 protein increased during the entire culture period, while glutamine synthetase activity remained low and relatively constant. The addition of an astroglial growth factor, partially purified from bovine brain soluble extract, stimulated the morphological maturation of the astroglial cells. The cells extended cytoplasmic processes and resembled mature astrocytes. At the ultrastructural level an increase in free ribosomes was observed and the intermediate filaments became organized into large bundles. The amount of glial fibrillary acidic protein was not significantly increased, but the level of S100 protein and the glutamine synthetase activity were greatly enhanced. Our results indicate that astroglial cells undergo limited maturation in the chemically defined medium and that this process is positively affected by the astroglial growth factor.
RESUMEN
Iodate poisoning is known to induce both a retinal degeneration which is restricted in a first stage to the pigment epithelium and a selective suppression of the c-wave ([5] to [10]). In the chicken we did not obtain such electrophysiological or morphological effects. In both acute (i.v. or i.m. injections, up 50 mg/kg) and chronic experiments (4 X 45 mg/kg daily) the photopic c-wave of the chicken appeared to be fairly insensitive to sodium iodate, except at high concentrations (greater than 100 mg/kg in a single injection) which proved to be highly cardiotoxic. The ultrastructure of the retinal pigment epithelium and of the photoreceptors appeared quite normal in retinas treated with the highest concentration of the drug. Sodium pentobarbital (Nembutal), ketamine (Ketalar) and ethyl-carbamate (Urethane) were used as general anesthetics. The c-wave appeared to be differentially sensitive to these drugs. The suppressant effect was strongest with Nembutal and lowest with Urethane. The selective sensitivity of the c-wave to general anesthetics may explain why it was repeatedly stated in the literature that c-waves did not exist in a number of cone dominated retinas.