Implementation of an Outpatient HD-MTX Initiative.

Introduction: Methotrexate (MTX) a folate antagonist is often given in high doses (≥500 mg/m) to treat a variety of disease processes. While inpatient administration has been the norm, outpatient administration, has been shown to be safe, effective, and patient centered. Here in we describe development of an outpatient HDMTX protocol and our initial experience.

Investigation of sugar binding kinetics of the E. coli sugar/H symporter XylE using solid-supported membrane-based electrophysiology.

Bacterial transporters are difficult to study using conventional electrophysiology because of their low transport rates and the small size of bacterial cells. Here, we applied solid-supported membrane-based electrophysiology to derive kinetic parameters of sugar translocation by the Escherichia coli xylose permease (XylE), including functionally relevant mutants. Many aspects of the fucose permease (FucP) and lactose permease (LacY) have also been investigated, which allow for more comprehensive conclusions regarding the mechanism of sugar translocation by transporters of the major facilitator superfamily.

Mutation of two key aspartate residues alters stoichiometry of the NhaB Na/H exchanger from Klebsiella pneumoniae.

Bacterial NhaB Na/H exchangers belonging to the Ion Transporter superfamily are poorly characterized in contrast to Na/H exchangers of the Cation Proton Antiporter superfamily which have NhaA from Escherichia coli as a prominent member. For a more detailed understanding of the intricacies of the exchanger's transport mechanism, mutational studies are essential. Therefore, we mutated two protonatable residues present in the putative transmembrane region of NhaB from Klebsiella pneumoniae (KpNhaB), which could serve as substrate binding sites, Asp146 and Asp404, to either glutamate or alanine and analyzed transport function and stability of the mutants using electrophysiological and fluorimetric techniques.

A channel profile report of the unusual K channel KtrB.

KtrAB is a key player in bacterial K uptake required for K homeostasis and osmoadaptation. The system is unique in structure and function. It consists of the K-translocating channel subunit KtrB, which forms a dimer in the membrane, and the soluble regulatory subunit KtrA, which attaches to the cytoplasmic side of the dimer as an octameric ring conferring Na and ATP dependency to the system.

Coupling efficiency of secondary active transporters.

Secondary active transporters are fundamental to a myriad of biological processes. They use the electrochemical gradient of one solute to drive transport of another solute against its concentration gradient. Central to this mechanism is that the transport of one does not occur in the absence of the other.