RESUMEN
IL-2 responses are susceptible to suppression by TGFbeta, a cytokine widely implicated in suppression of inflammatory responses and secreted by many different tumor cell types. There have been conflicting reports regarding inhibition of IL-2-induced STAT3 and STAT5 phosphorylation by TGFbeta and subsequent suppression of immune responses. Using TGFbeta-producing multiple myeloma tumor cells we demonstrate that tumor-derived TGFbeta can block IL-2-induced proliferation and STAT3 and STAT5 phosphorylation in T cells. High affinity IL-2R expression was required for the suppression of IL-2 responses as a novel CD25(-) T cell line proliferated and phosphorylated STAT3 when cultured with tumor cells or rTGFbeta1. Activating T cells with IL-15, which does not use the high affinity IL-2R, completely restored the ability of T cells to phosphorylate STAT3 and STAT5 when cultured with tumor cells. IL-15-treated T cells proliferated normally when cocultured with tumor cells or rTGFbeta1, whereas IL-2 responses were consistently inhibited. Preincubation with IL-15 also restored the ability of T cells to respond to IL-2 by phosphorylating STAT3 and STAT5, and proliferating normally in the presence of tumor cells. IL-2 pretreatment did not restore T cell function. IL-15 also restored T cell responses by T cells from multiple myeloma patients, and against freshly isolated bone marrow tumor samples. Thus, activation of T cells by IL-15 renders T cells resistant to suppression by TGFbeta1-producing tumor cells and rTGFbeta1. This finding may be exploited in the design of new immunotherapy approaches that will rely on T cells avoiding tumor-induced suppression.
Asunto(s)
Proteínas de Unión al ADN/antagonistas & inhibidores , Inmunosupresores/antagonistas & inhibidores , Interleucina-15/fisiología , Interleucina-2/antagonistas & inhibidores , Activación de Linfocitos/inmunología , Proteínas de la Leche , Proteínas de Neoplasias/fisiología , Linfocitos T/inmunología , Transactivadores/antagonistas & inhibidores , Factor de Crecimiento Transformador beta/fisiología , Células Cultivadas , Técnicas de Cocultivo , Proteínas de Unión al ADN/metabolismo , Humanos , Inmunosupresores/farmacología , Interleucina-15/biosíntesis , Interleucina-2/fisiología , Activación de Macrófagos , Monocitos/inmunología , Monocitos/metabolismo , Mieloma Múltiple/inmunología , Mieloma Múltiple/patología , Proteínas de Neoplasias/antagonistas & inhibidores , Fosforilación , Receptores de Interleucina-2/biosíntesis , Factor de Transcripción STAT3 , Factor de Transcripción STAT5 , Transducción de Señal/inmunología , Linfocitos T/patología , Transactivadores/metabolismo , Factor de Crecimiento Transformador beta/antagonistas & inhibidores , Células Tumorales CultivadasRESUMEN
Multiple myeloma (MM) is a cancer of plasma cells, characterized by profound suppression of host immune responses. Here we show that MM cell lines significantly suppress the proliferation, blasting, response to interleukin-2 (IL-2), and expression of CD25 by concanavalin A (Con A)-activated or allostimulated peripheral blood T lymphocytes. T cells arrest in the G1 stage of the cell cycle, and do not enter the IL-2 autocrine growth pathway. T cell inhibition was mediated by a soluble factor. MM cell lines did not produce IL-10 but did produce large amounts of transforming growth factor beta1 (TGF-beta1). T cells were assessed for their ability to respond to IL-2 when co-cultured with MM cells in the presence or absence of the TGF-beta inhibitor, TGF-beta latency-associated peptide (LAP). MM cells suppressed IL-2 responses but this inhibition was completely reversed by TGF-beta LAP. A CD25-, IL-2-dependent blast cell line was not inhibited by MM cells or rhTGF-beta, confirming the specificity of the inhibition mechanism for the IL-2 autocrine growth pathway. We conclude that MM cells suppress T cells in their entry into the autocrine IL-2/CD25 pathway and in response to IL-2, and that TGF-beta has a significant role to play.
Asunto(s)
Adyuvantes Inmunológicos/antagonistas & inhibidores , Interleucina-2/antagonistas & inhibidores , Activación de Linfocitos/inmunología , Mieloma Múltiple/inmunología , Fragmentos de Péptidos , Precursores de Proteínas , Linfocitos T/inmunología , Factor de Crecimiento Transformador beta/farmacología , Adyuvantes Inmunológicos/fisiología , Apoptosis/inmunología , Comunicación Celular/inmunología , Ciclo Celular/inmunología , Técnicas de Cocultivo , Concanavalina A/antagonistas & inhibidores , Humanos , Interleucina-2/fisiología , Activación de Linfocitos/efectos de los fármacos , Prueba de Cultivo Mixto de Linfocitos , Mitógenos/antagonistas & inhibidores , Mieloma Múltiple/metabolismo , Mieloma Múltiple/patología , Proteínas/farmacología , Receptores de Interleucina-2/biosíntesis , Proteínas Recombinantes/farmacología , Linfocitos T/citología , Linfocitos T/metabolismo , Factor de Crecimiento Transformador beta/biosíntesis , Factor de Crecimiento Transformador beta1 , Células Tumorales CultivadasRESUMEN
Immediate access to off-site expert diagnostic consultants regarding unusual radiographic findings or radiographic quality assurance issues could be a current problem for private dental practitioners. Teleradiology, a system for transmitting radiographic images, offers a potential solution to this problem. Although much research has been done to evaluate feasibility and utilization of teleradiology systems in medical imaging, little research on dental applications has been performed. In this investigation 47 panoramic films with an equal distribution of images with intraosseous jaw lesions and no disease were viewed by a panel of observers with teleradiology and conventional viewing methods. The teleradiology system consisted of an analog video-based system simulating remote radiographic consultation between a general dentist and a dental imaging specialist. Conventional viewing consisted of traditional viewbox methods. Observers were asked to identify the presence or absence of 24 intraosseous lesions and to determine their locations. No statistically significant differences in modalities or observers were identified between methods at the 0.05 level. The results indicate that viewing intraosseous lesions of video-based panoramic images is equal to conventional light box viewing.
Asunto(s)
Radiografía Panorámica/instrumentación , Telerradiología/instrumentación , Análisis de Varianza , Femenino , Humanos , Maxilares/diagnóstico por imagen , Enfermedades Maxilomandibulares/diagnóstico por imagen , Masculino , Curva ROC , Intensificación de Imagen Radiográfica/instrumentación , Intensificación de Imagen Radiográfica/normas , Radiografía Panorámica/normas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Telerradiología/normas , Grabación en VideoRESUMEN
Transient apical breakdown has been reported to occur in cases in which a periapical radiolucency develops and resolves without treatment following luxation injury. Diagnostic errors are inevitable if periapical breakdown is used as the sole criterion or as an overriding criterion in the decision to initiate root canal treatment. A clinical case report is presented in which transient apical breakdown occurred after a subluxation injury. The threshold to sensitivity tests increased yet sensitivity remained positive with the appearance of the periapical radiolucency. The decision was made not to initiate root canal treatment in spite of the radiographic appearance periapically. At the 10-month recall the tooth remained responsive to sensitivity tests and the apical radiolucency had disappeared.
Asunto(s)
Enfermedades Periapicales/etiología , Avulsión de Diente/complicaciones , Baloncesto/lesiones , Prueba de la Pulpa Dental , Humanos , Incisivo/lesiones , Masculino , Persona de Mediana Edad , Enfermedades Periapicales/diagnóstico por imagen , Valor Predictivo de las Pruebas , Pronóstico , RadiografíaRESUMEN
A common way of sterilizing endodontic files for clinical use is to insert them into synthetic sponges. The files are sterilized in the sponge, and the sponge is then used on the patient tray for ease of file retrieval. The ability to sterilize the files in a sponge has been questioned. The purpose of the present investigation was to evaluate the sterility of files and spore strips following autoclaving in a sponge. Commercial spore strips and contaminated endodontic files were inserted into sponges, sealed in sterilization pouches and autoclaved. The spore strips and the files were removed from the sponge and cultured for growth of microorganisms. Results show that no microbes were cultured from spore strips or contaminated files after autoclaving them in the sponges sealed in autoclave pouches. These results indicate that the insertion of files into the sponges used in this study does not obstruct the autoclaving process.
Asunto(s)
Endodoncia/instrumentación , Control de Infecciones/métodos , Esterilización/métodos , Recuento de Colonia Microbiana , Monitoreo del Ambiente , Contaminación de Equipos , Estudios de Evaluación como Asunto , Geobacillus stearothermophilus/crecimiento & desarrollo , Calor , Esporas BacterianasRESUMEN
Fine structural details of the parasitic yeastlike phase of Sporothrix schenckii contained in biopsy tissue from a naturally-occurring case of disseminated feline sporotrichosis are described and illustrated by electron microscopy. Both free and phagocytosed fungal cells were observed. The fungal cells were contained within an extracellular, electron transparent vacuolar area which was bounded by a limiting membrane of probable host origin. The yeastlike cells were characterized by a conspicuous layer of osmiophilic microfilaments which occurred along the outermost surface of the cell wall. In many yeastlike cells, scattered, membrane-bound vacuoles containing electron opaque material were observed in the cytoplasm. Asteroid bodies were not observed.
Asunto(s)
Enfermedades de los Gatos/parasitología , Sporothrix/ultraestructura , Esporotricosis/veterinaria , Animales , Gatos , Microscopía Electrónica , Piel/parasitología , Piel/patología , Esporotricosis/diagnósticoRESUMEN
Fine details of perithecial morphology and aspects of ascospore formation of Ceratocystis stenoceras (Robak) C. Moreau are shown in electron micrographs of ultrathin sections. The envelope of the perithecial body proper consisted of two zones of cells which differed morphologically one from another. Loose aggregates of small electron opaque particles were present at the outer wall surface which may be responsible for the characteristic pigmentation of the body and neck. Cells comprising the ostiolate neck may arise as modifications of spindle-shaped cells of the inner zone of the perithecial envelope. Cell walls of the neck and of zones 1 and 2 may be composed in part of periodic acid-reactive polysaccharide. The perithecial envelope and ascogenous cells were separated by a band of several parallel, double-layered membranes which may function in some manner with biosynthetic activities of ascospore production. In general, the mechanics of ascospore formation by C. stenoceras were in most ways in agreement with recent reports of ascospore outogeny in other ascomycetous fungi. Mature ascospores were somewhat lenticular in shape and the outer space wall was finely sculptured.
Asunto(s)
Ascomicetos/citología , Frutas , Ascomicetos/análisis , Ascomicetos/fisiología , Membrana Celular/ultraestructura , Microscopía Electrónica , Pigmentación , Polisacáridos/análisis , Esporas FúngicasRESUMEN
Fine details of yeastlike cell development of Blastomyces dermatitidis from its conidium are described and illustrated by electron micrographs. When cultured in an enriched medium at 37C, conidia of two strains of B. dermatitidis readily underwent ultrastructural changes consistent with mycelial to yeast dimorphism. Although hyphal cells contained in the conversion cultures were observed consistently to undergo profound degenerative changes, the conidia rapidly germinated to give rise to short germ tubes which subsequently enlarged to form intermediate yeast mother cells (YMC). The wall of the germ tube arose from the innermost layer of the wall of the germinant. During the transition globoid osmiophilic inclusions of unknown origin and function were observed in vacuolated areas of the germ tube and YMC cytoplasm. Yeastlike daughter cells then budded from the intermediate YMC. Since transformation was readily accomplished under in vitro conditions favoring mycelial to yeast dimorphism, it is suggested that the conidium of B. dermatitidis represents the primary infective unit of this pathogenic fungus.
Asunto(s)
Blastomyces/crecimiento & desarrollo , Polimorfismo Genético , Blastomyces/ultraestructura , Pared Celular/ultraestructura , Medios de Cultivo , Cuerpos de Inclusión/ultraestructura , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/ultraestructuraRESUMEN
Fine details of the sequential morphological events occurring during transition of microconidia (spores less than 5 micrometer in diameter) to the yeastlike phase of Histoplasma capsulatum as seen in ultrathin section are described and illustrated by electron micrographs. Masses of microconidia were obtained when the fungas was grown on a garden soil extract medium. Spores were incubated under in vitro environmental conditions conducive for phase transition (an enriched medium at 37 degrees C). Within 48 h of incubation, the microconidia either germinated to give rise to a short mycelium or the germ tube process became a yeast mother cell without further extension. The wall of the yeast mother cell was thin and smooth, and its cytoplasmic content was ultrastructurally complex, consisting of numerous lipid bodies, vacuoles, glycogen-like deposits, and membrane systems. Within 96 h, the mother cell underwent multipolar budding to form simultaneously linear hyphal and/or ovate yeastlike daughter cells. During the transition, new cell wall materials of the germ tube, the mother cell, and yeastlike daughter cells arose by blastic action from the innermost layer(s) of the wall of the precursor form. Lomasome-like vesicles were often seen in association with areas of new cell wall formation. After organellar migration into and septation of the daughter cells, the yeast mother cell's cytoplasmic content underwent marked degenerative changes.
Asunto(s)
Histoplasma/ultraestructura , Histoplasma/crecimiento & desarrollo , Microscopía Electrónica , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/ultraestructuraRESUMEN
Electron microscopy of 8 strains of Sporothrix schenckii and 1 strain each of Ceratocystis stenoceras, C. pluriannulata, C. ulmi, and C. minor revealed the presence of unusual osmiophilic structures (EOB) which appeared as normal organellar components of young cells of these fungi. In S. schenckii and C. stenoceras, these structures were markedly osmiophilic, reacted strongly with thiocarbohydrazide, could be partially solubilized with the lipid solvent sodium methoxide, and appeared to possess lipase activity. On subsequent cellular ageing, lipid bodies were commonly seen in intimate association with the EOB. Eventually, the EOB underwent degeneration and extensive vacuolization. It is suggested that these structures are composed in part of lipoidal material in possible association with a protein matrix, and may be in some manner involved with lipid metabolism of mechanisms of lipid storage.
Asunto(s)
Ascomicetos/ultraestructura , Organoides/ultraestructura , Sporothrix/ultraestructura , Microscopía ElectrónicaRESUMEN
Aspects of the fine structure of germinating microconidia (spore less than 5 micron in diameter) and vegetative hyphal cells of Histoplasma capsulatum were examined by electron microscopy. When grown on a soil extract medium, three strains produced masses of smooth-walled conidia when the conidia were examined by light microscopy. Electron microscopy showed the presence of short tuberculations arising as part of the outer layer of the microconidial wall. Within 48 h of incubation at 25 degrees C, germination was initiated by the emergence of a short germ tube whose wall was derived from an inner layer(s) of the cell wall of the germinant. Germ tube formation was occasionally multipolar. Following the initiation of germination, organeller migration and septation, the microcondium rapidly lost its morphological identity. The cytoplasm of the vegetative hyphal cell was observed to contain typical fungal organelles. The septal area was characteristic of that of a ascomycetous fungus.
Asunto(s)
Histoplasma/ultraestructura , Diferenciación Celular , Histoplasma/crecimiento & desarrollo , Microscopía ElectrónicaRESUMEN
Rothia dentocariosa was seen as a typical prokaryotic cell, lacking nuclear envelope, mitochondria and a reticulum with ribosomes. The plasma membrane was located close to and parallel to the wall. The outer limits of the wall were associated with what may be capsular or slime material. Chain-like filaments of thick walled coccoid cells underwent septation both transverse and parallel to the long axis of the chain. Side branching and terminal clavate forms were also present. These clavate forms may represent specialized cells during the life-cycle. Fragmentation of the chain resulted when the outer wall ruptured to release the coccoid bodies.
Asunto(s)
Actinomycetaceae/ultraestructura , Membrana Celular/ultraestructura , Pared Celular/ultraestructura , Microscopía Electrónica , Morfogénesis , Boca/microbiologíaRESUMEN
Fine details of the internal and external morphology of the in vitro mycelial phase (MP) to yeastlike phase (YP) transition of the dimorphic fungal pathogen Sporothrix schenckii are shown in electron micrographs of ultrathin sections. Morphological transformation at the ultrastructural level was observed to occur by direct formation of budlike structures at the tips and along the hyphae and by oidial cell formation. Direct budding of yeast from conidiospores was not observed. Early transitional forms arising by direct blastic action from the MP possessed conspicuous electron-dense microfibrillar material at the outer limits of the cell wall. The electron density of this microfibrillar material was enhanced by staining with acidified dialyzed iron. It is believed that this extracellular material may be composed in part of an acid mucosubstance. No acid phosphatase activity was associated with this microfibrillar material. This substance was found to be a characteristic of the outer limits of the cell wall of the YP of S. schenckii. Oidial YP cell formation occurred later during the transition. The cell wall of the developing oidial YP transitional form arose from an inner layer of the converting hyphae. No consupicuous alterations of the cytoplasmic content of the parent MP cell was observed during MP-to-YP transition. It is suggested that the MP-to-YP transition of S. schenckii may be regulated by at least two mechanisms involving alterations of the biochemical and/or biophysical nature of the cell wall of the MP cell in response to the conversional stimuli.
Asunto(s)
Sporothrix/ultraestructura , Pared Celular/ultraestructura , Microscopía Electrónica , Organoides/ultraestructura , Polimorfismo Genético , Sporothrix/crecimiento & desarrolloRESUMEN
Aspects of the fine structure as well as electron cytochemical localization studies of certain hydrolytic enzymes were examined by electron microscopy of ultrathin sections of the vegatative hyphae and conidia of the phycomycetous fungus, Entomophthora coronata. This entomogenous fungal organism is of interest since it has been increasingly implicated as the etiologic agent of phycomycosis of man and animals. On thin section, hyphal cells were frequently observed with septa while the cytoplasm was multinucleate. The conidium was bound by a multilayered cell wall. The cytoplasm of ungerminated conidia characteristically contained large numbers of a class of cytoplasmic organelle found in loose aggregates with lipid storage bodies. Similar organelles were observed in the cytoplasm of hyphal cells from 7-day old cultures. This round to oval to slightly reniform structure was bound by a single limiting membrane and composed of an electron dense, slightly granular matrix without evidence of crystalloid formation. The limiting membrane of the lipid storage bodies was observed to be intimately associated with that of one or more of these microbody-like organelles. This intimate association of the two cytoplasmic organelles suggests that the microbody-like organelle may be involved in some manner with lipid metabolism during the life cycle of the fungus. Cautious interpretations of electron cytochemical localization studies suggested that lipase, nonspecific esterase, and possibly aryl sulfatase were associated with the microbody-like organelles. Neither peroxidatic nor acid phosphatase activity could be demonstrated with these organelles of the conidial cytoplasm.
Asunto(s)
Entomophthora/ultraestructura , Hongos/ultraestructura , Arilsulfatasas/metabolismo , Catalasa/metabolismo , Entomophthora/enzimología , Histocitoquímica , Lipasa/metabolismo , Microcuerpos/enzimología , Microcuerpos/metabolismo , Microscopía Electrónica , Micosis/etiologíaRESUMEN
Within 48h following the induction of mycelial to yeast-like phase conversion of Histoplasma farcininosum, randomly occurring hyphal cells were observed to contain multiple nuclei and markedly increased numbers of mitochondria. Yeast-like cells arose as buds from swollen tips of terminal hyphae, as sessile buds along the hyphae, and as buds from chlamydospores. Yeast-like cells were characterized by the presence of numerous buds over the surface of the mother cell. Bud scars were evident in the cell wall of the mother cell following abscission of the bud cell. Little similarity was noted between the fine structure of yeast-like H. farciminosum and that reported for H. capsulatum. The yeast-like cells of H. frciminosum underwent rapid transformation to the mycelial phase at 25 degrees C. The hyphal cell wall originated from the inner layer of cell wall of the yeast-like form. The cytoplasm of the hyphal cell usually contained a single nucleus, scattered mitochondria and occasional lipid storage bodies. Occasionally, Woronin bodies were observed at the septal pore.