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61.
Wistar-Lewis rats were anesthetized anc connected to a 3-MHz nebulizer which aerosolized 250 muCi l-alpha-1-palmitoyl-2palmitoyl-[9-10-3H]phosphatidylcholine ([3H]DPL) for 3 min. Appleton frozen-section autoradiographs showed greater than 4 times background radioactivity in approximately 30% of alveoli at 1 min and 2 h after aerosol. As tritium content in the lung decreased, it increased in liver, spleen, kidney, blood, and urine. Percentage of radioactivity from [3H]phosphatidylcholine in the liver declined with time, while [3H]phosphatidylethanolamine doubled between 2 and 12 h. One minute postaerosol 2,500 +/- 500 (SE) type I cells/mm3 lung and 2,500 +/- 750 type II cells/mm3 lung had greater than 20 times background radioactivity; 2 h later only 950 +/- 250 type I cells/-m3 lung still had levels of radioactivity greater than 20 times background while 3,150 +/- 600 type II cells/mm3 lumg now had this level of 3HIDPL. Corresponding numbers of alveolar macrophages were 450 +/- 250 1 min postaerosol and 1,100 +/- 200 after 2 h. Aerosolized DPL as a synthetic surfactant is hampered by significantly faster clearance from the alveolar surface as compared with normal in vivo DPL. 相似文献
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Mark E. Costlow Patricia E. Gallagher 《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,587(2):192-201
Concanavalin A, which binds to specific carbohydrate determinants on the cell surface, was used to investigate the binding of prolactin to its receptors in liver membranes from female rats. The binding of 125I-labeled ovine prolactin to receptors was sharply inhibited by concanavalin A. This effect was reversed by the competitive sugar α-methyl-D-mannopyranoside and thus required the presence of specifically bound lectin. Concentrations of concanavalin A of up to 50 μg/ml caused a progressive decrease in the apparent affinity of the prolactin receptor for hormone. When higher concentrations were used, the number of available binding sites decreased. Concanavalin A-resistant receptors, about 30% of the total, had the same dissociation constant (Kd) as the controls. The binding of 125I-labeled concanavalin A in the same membrane preparations showed the presence of two distinct types of concanavalin A binding. At low concentrations, the lectin bound with high affinity (Kd ≈ 6.6 · 10?8 M). At high lectin concentrations, low affinity (Kd ≈ 6.7 · 10?5 M) binding predominated. Since high affinity concanavalin A binding was saturated at 50 μg/ml, this class of binding most likely alters the affinity of the prolactin receptor for hormone; low affinity concanavalin A binding may mask prolactin receptors, making them inaccessible to the hormone.Binding sites for concanavalin A and prolactin appear to be independent but closely related since (i) concanavalin A did not displace bound prolactin from its receptor, and (ii) detergent-solubilized 125I-labeled prolactin-receptor complexes bound to concanavalin A-Sepharose and were eluted by α-methyl-D-mannopyranoside. 相似文献
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Clemens Alexander Boecker Mara A. Olenick Elizabeth R. Gallagher Michael E. Ward Erika L. F. Holzbaur 《Traffic (Copenhagen, Denmark)》2020,21(1):138-155
Induced pluripotent stem cells (iPSCs) hold promise to revolutionize studies of intracellular transport in live human neurons and to shed new light on the role of dysfunctional transport in neurodegenerative disorders. Here, we describe an approach for live imaging of axonal and dendritic transport in iPSC‐derived cortical neurons. We use transfection and transient expression of genetically‐encoded fluorescent markers to characterize the motility of Rab‐positive vesicles, including early, late and recycling endosomes, as well as autophagosomes and mitochondria in iPSC‐derived neurons. Comparing transport parameters of these organelles with data from primary rat hippocampal neurons, we uncover remarkable similarities. In addition, we generated lysosomal‐associated membrane protein 1 (LAMP1)‐enhanced green fluorescent protein (EGFP) knock‐in iPSCs and show that knock‐in neurons can be used to study the transport of endogenously labeled vesicles, as a parallel approach to the transient overexpression of fluorescently labeled organelle markers. 相似文献
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Abdullah Al Emran Hsin‐Yi Tseng Mikaela C. Coleman Jessamy Tiffen Stuart Cook Helen M. McGuire Stuart Gallagher Carl Feng Peter Hersey 《Pigment cell & melanoma research》2020,33(5):660-670
Melanoma, as for many other cancers, undergoes a selection process during progression that limits many innate and adaptive tumor control mechanisms. Immunotherapy with immune checkpoint blockade overcomes one of the escape mechanisms but if the tumor is not eliminated other escape mechanisms evolve that require new approaches for tumor control. Some of the innate mechanisms that have evolved against infections with microorganisms and viruses are proving to be active against cancer cells but require better understanding of how they are activated and what inhibitory mechanisms may need to be targeted. This is particularly so for inflammasomes which have evolved against many different organisms and which recruit a number of cytotoxic mechanisms that remain poorly understood. Equally important is understanding of where these mechanisms will fit into existing treatment strategies and whether existing strategies already involve the innate killing mechanisms. 相似文献
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