c-Met is a well-characterized receptor tyrosine kinase for hepatocyte growth factor (HGF). Compelling evidence from studies in human tumors and both cellular and animal tumor models indicates that signaling through the HGF/c-Met pathway mediates a plethora of normal cellular activities, including proliferation, survival, migration, and invasion, that are at the root of cancer cell dysregulation, tumorigenesis, and tumor metastasis. Inhibiting HGF-mediated signaling may provide a novel therapeutic approach for treating patients with a broad spectrum of human tumors. Toward this goal, we generated and characterized five different fully human monoclonal antibodies that bound to and neutralized human HGF. Antibodies with subnanomolar affinities for HGF blocked binding of human HGF to c-Met and inhibited HGF-mediated c-Met phosphorylation, cell proliferation, survival, and invasion. Using a series of human-mouse chimeric HGF proteins, we showed that the neutralizing antibodies bind to a unique epitope in the B-chain of human HGF. Importantly, these antibodies inhibited HGF-dependent autocrine-driven tumor growth and caused significant regression of established U-87 MG tumor xenografts. Treatment with anti-HGF antibody rapidly inhibited tumor cell proliferation and significantly increased the proportion of apoptotic U-87 MG tumor cells in vivo. These results suggest that an antibody to an epitope in the B-chain of HGF has potential as a novel therapeutic agent for treating patients with HGF-dependent tumors.
Viroids are small, nontranslatable pathogenic RNAs that replicate autonomously and traffic systemically in their host plants. We have used in situ hybridization to analyze the trafficking pattern of Potato spindle tuber viroid (PSTVd) in tomato and Nicotiana benthamiana. When PSTVd was inoculated onto the stem of a plant, it replicated and trafficked to sink, but not source, leaves. PSTVd was absent from shoot apical meristems. In the flowers of infected plants, PSTVd was present in the sepals, but was absent in the petals, stamens, and ovary. The replicative form of PSTVd was detected in the phloem. Our data demonstrate that (i) PSTVd traffics long distance in the phloem and this trafficking is likely sustained by replication of the viroid in the phloem, and (ii) PSTVd trafficking is governed by plant developmental and cellular factors. The dependency of PSTVd and other viroids on cellular mechanisms for RNA trafficking makes them excellent tools to study such mechanisms.
Pharmacists will play a key role in evaluating biosimilars for formulary inclusion in the United States. As defined by US law, a biosimilar is a biologic that is highly similar to its reference product, notwithstanding minor differences in clinically inactive components, and should not have clinically meaningful differences from its reference product in safety, purity, and potency. We review biosimilars and the current European Union and US regulatory pathways for biosimilars. Furthermore, we propose a checklist of considerations to ensure that US pharmacists thoroughly evaluate future biosimilars for formulary inclusion. Included in the checklist are considerations related to the availability of preapproval and postapproval safety and efficacy data; differences in product characteristics and immunogenicity between the biosimilar and reference product; manufacturer-related parameters that can affect a reliable supply of quality products; health-system and patient perspectives on product packaging, labeling, storage, and administration; costs and insurance coverage; patient education; interchangeability and differences in the range of indications; and evaluation of institutions' information technology systems.
The ecology of children's medical care is similar to that of adults in the United States in that a substantial proportion of children receive health care each month, mostly in community-based, outpatient settings. In all settings except emergency departments, receipt of care varies significantly by children's age, race, ethnicity, income, health insurance status, and whether they have a usual source of care.
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