Asunto(s)
Ensayos Clínicos Controlados como Asunto/historia , Ensayos Clínicos Controlados Aleatorios como Asunto/historia , Antibióticos Antituberculosos/historia , Antibióticos Antituberculosos/uso terapéutico , Resfriado Común/tratamiento farmacológico , Resfriado Común/historia , Historia del Siglo XX , Humanos , Patulina/historia , Patulina/uso terapéutico , Estreptomicina/historia , Estreptomicina/uso terapéutico , Tuberculosis/tratamiento farmacológico , Tuberculosis/historiaRESUMEN
Perinuclear vesicles (estimated diameter less than 0.15 micron), too small to be seen in living mouse macrophages by direct phase-contrast microscopy, could be detected by darkfield microscopy thanks to their rapid non-saltatory movements at 37 degrees C, contrasting with the slower saltations of accompanying phase-visible larger vesicles (0.25-0.5 micron, presumed secondary lysosomes). The movements of these 'small visicles' also differed from those of the 'larger visicles' in their responses to changes in temperature, and to chemical agents known to inhibit both the saltations of secondary lysosomes and the latter's fusion with phagosomes. Thus the 'larger vesicles' stopped moving at 25 degrees C, the small ones did not; both stopped at 18 degrees C. The 'small vesicles' continued to move actively after cell uptake of the polyanion poly-D-glutamic acid, while the saltations of the 'larger vesicles' were markedly slowed; both sets of vesicles stopped after uptake of ammonium chloride. Degranulation of the small vesicles paralleled that of the larger, while simultaneously observed preformed pinosomes (labelled with fluorescent wheat germ agglutinin (WGA) appeared to be unaffected. On the basis also of refractivity, location and speed the 'small vesicles' are considered not to be pinosomes, but probably to be lysosomes. The question of whether they are a subgroup of small immature secondary lysosomes or primary lysosomes (0.05-0.08 micron) is discussed. The broad spectrum of movement inhibited by ammonia in macrophages raises the possibility that this weak base inhibits movements of all lysosomes. Further characterization of these 'small vesicles' requires their relation to be defined to the small particles in other cell types (especially in axoplasm) which have been detected by video-enhanced microscopy.
Asunto(s)
Lisosomas/fisiología , Macrófagos/ultraestructura , Cloruro de Amonio/farmacología , Animales , Lisosomas/efectos de los fármacos , Lisosomas/ultraestructura , Ratones , Microscopía , Movimiento , Organoides/efectos de los fármacos , Organoides/fisiología , Organoides/ultraestructura , Pinocitosis , Ácido Poliglutámico/farmacología , TemperaturaRESUMEN
Intravascular pH was measured within the lysosomes and newly formed phagosomes in cultured mouse peritoneal macrophages. The kinetics of pH change in both vacuolar systems was quantitatively determined within a large cell population by fluorescence spectroscopy. Additionally, pH changes within individual phagosomes were followed semiquantitatively using indicator dyes. Two novel findings were made. Firstly, the pH in new phagosomes was transiently driven alkaline (higher than physiological) even when the external medium was buffered at pH 6.5. Secondly, perturbations of phagosome-lysosome fusion had little effect upon phagosomal pH changes, even though the compounds used markedly altered the pH of the lysosomes in resting and phagocytosing cells.
Asunto(s)
Lisosomas/metabolismo , Macrófagos/ultraestructura , Fagocitosis , Amilosa/análogos & derivados , Amilosa/farmacología , Animales , Líquido Ascítico , Línea Celular , Cricetinae , Concentración de Iones de Hidrógeno , Riñón , Ratones , Organoides/metabolismo , Ácido Poliglutámico/farmacología , Espectrometría de FluorescenciaRESUMEN
Intracellular parasites (e.g., Mycobacterium tuberculosis, Toxoplasma gondii, and some Chlamydiae) may promote their survival within the host by acting from within phagosomes to prevent phagolysosome formation, thus avoiding exposure to the lysosomal hydrolases. The present studies demonstrate that when sulfatides of M. tuberculosis (anionic trehalose glycolipids largely responsible for the neutral red reactivity of virulent strains) are administered to cultured mouse peritoneal macrophages, they accumulate in the secondary lysosomes, which are rendered incompetent for fusion with phagosomes containing suitable target particles such as viable yeasts. This antifusion effect is also exhibited when small amounts of sulfatide are introduced directly into phagosomes by attachment to the target yeasts prior to their ingestion. The sulfatides evidently exert a selective inhibitory influence on membrane fusion, analogous to what occurs typically when macrophage cultures are infected with tubercle bacilli. This effect may be due to ionic interaction between the polyanionic micelles of bacterial sulfatide and organelle membranes, modifying the latter and inducing dysfunction.