John M. Robinson

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Cerium ions have been used as the capture agent for inorganic phosphate released during the enzymatic hydrolysis of phosphate-containing substrates by a variety of phosphatases. Cerium phosphate reaction product accumulation is proportional to the amount of enzyme present in a cell-free model system. Ultrastructurally, cerium phosphate reaction product(More)
In this study, we show that superoxide production is carried out within intracellular compartments of human neutrophils and not at the plasma membrane following stimulation with phorbol myristate acetate. Oxidant production was not observed in unstimulated cells. Stimulated cells exhibited superoxide production in two distinct types of intracellular(More)
The inverse relationship between serum albumin concentration and its half-life suggested to early workers that albumin would be protected from a catabolic fate by a receptor-mediated mechanism much like that proposed for IgG. We show here that albumin binds FcRn in a pH dependent fashion, that the lifespan of albumin is shortened in FcRn-deficient mice, and(More)
Human neutrophils contain a novel intracellular compartment that is distinct from the previously characterized azurophil and specific granules. This compartment is distinguished by the presence of cytochemically detectable alkaline phosphatase activity. The alkaline phosphatase-containing compartments are short rod-shaped organelles that rapidly undergo a(More)
Immunocytochemistry provides important information on the localization of antigens in cells and tissues. However, the procedures used to prepare cells and tissues for immunocytochemical labeling may have deleterious effects on the results achieved. That is, the antigen of interest may be difficult or impossible to detect following labeling. These sorts of(More)
To evaluate the potential role of human placental endothelial cells in the transport of IgG from maternal to fetal circulation, we studied Fc gamma receptor (Fc gamma R) expression by immunohistology and immunoblotting. Several pan-Fc gamma RII Abs that label the placental endothelium displayed a distribution pattern that correlated well with transport(More)
A cytochemical method for 5'-nucleotidase localization in which cerium serves as the capture agent in order to enzymatically detect liberated inorganic phosphate has been developed. The method has been established in cell-free model systems and in guinea pig neutrophils where 5'-nucleotidase is restricted to the plasmalemma as an ectoenzyme. This(More)
Several investigators [1] have outlined techniques for culturing glomerular cells but many of these methods resulted in mixed cell populations and an inability to passage the cells consistently. There is also a lack of good criteria for cell identification. Previously, Kreisberg, Hoover, and Karnovsky [21 devised techniques in which they were able to(More)
The MHC-related Fc receptor for IgG (FcRn) protects albumin and IgG from degradation by binding both proteins with high affinity at low pH in the acid endosome and diverting both from a lysosomal pathway, returning them to the extracellular compartment. Immunoblotting and surface plasmon resonance studies show that both IgG and albumin bind noncooperatively(More)
To test whether a major contribution of airways epithelial ion transport to lung defense reflects the regulation of airway surface liquid (ASL) ionic composition, we measured ASL composition using the filter paper technique. On nasal surfaces, the Cl- concentration (approximately 125 meq/liter) was similar to plasma, but the Na+ concentration (approximately(More)