A boronate ester crosslinked zwitterionic nanogel (NGCA) with ATP/pH-sensitivity has been developed with an inverse nanoprecipitation technique to achieve a two-stage charge conversion that responds to tumor extracellular conditions (pH 6.5-6.8) and an intracellular acidic environment (pH 5-6). Cationic cytochrome C (CC), a therapeutic protein, has been encapsulated into NGCA through inverse na...

To better understand smoking cessation, we examined the actions of varenicline (Chantix) during long-term nicotine exposure. Varenicline reduced nicotine upregulation of α4β2-type nicotinic receptors (α4β2Rs) in live cells and neurons, but not for membrane preparations. Effects on upregulation depended on intracellular pH homeostasis and were not observed if acidic pH in intracellular compartme...

Listeriolysin O (LLO) is a cholesterol-dependent cytolysin that is an essential virulence factor of Listeria monocytogenes. LLO pore-forming activity is pH-dependent; it is active at acidic pH (<6), but not at neutral pH. In contrast to other pH-dependent toxins, we have determined that LLO pore-forming activity is controlled by a rapid and irreversible denaturation of its structure at neutral ...

Peptide binding by class II major histocompatibility complex proteins is generally enhanced at low pH in the range of hydrogen ion concentrations found in the endosomal compartments of antigen-presenting cells. We and others have proposed that class II molecules undergo a reversible conformational change at low pH that is associated with enhanced peptide loading. However, no one has previously ...

OBJECTIVES This study was designed to investigate the activation of the unfolded protein response (UPR) in tumor associated endothelial cells (TECs) and its association with chemoresistance during acidic pH stress. MATERIALS AND METHODS Endothelial cells from human oral squamous cell carcinomas (OSCC) were excised by laser capture microdissection (LCM) followed by analysis of UPR markers (Grp...

Bovine spongiform encephalopathy (BSE), or mad cow disease, is a fatal neurodegenerative disease that is transmissible to humans and that is currently incurable. BSE is caused by the prion protein (PrP), which adopts two conformers; PrPC is the native innocuous form, which is α-helix rich; and PrPSc is the β-sheet rich misfolded form, which is infectious and forms neurotoxic species. Acidic pH ...

Due to increased glycolysis and poor local perfusion, solid tumors are usually immersed in an acidic microenvironment. While extracellular acidosis is cytotoxic, cancer cells eventually become acclimated to it. While previous studies have addressed the acute effect of acidosis on cancer cells, little is known about how cancer cells survive chronic acidosis. In this study we exposed colorectal c...

Normal calf ao-mannosidase activity exists in at least three forms separable by chromatography on DEAE-cellulose and by starch-gel electrophoresis. Two components, A and B, have optimum activity between pH 3.75 and 4.75, but component C has an optimum of pH 6.6. Components A and B are virtually absent from the tissues of a calf with mannosidosis and the residual activity is due to component C. ...

Pyrazinamide (PZA) is an important antituberculosis drug. Unlike most antibacterial agents, PZA, despite its remarkable in vivo activity, has no activity against Mycobacterium tuberculosis in vitro except at an acidic pH. M. tuberculosis is uniquely susceptible to PZA, but other mycobacteria as well as nonmycobacteria are intrinsically resistant. The role of acidic pH in PZA action and the basi...

This study evaluated the effects of acidic medicines (Dimetapp and Claritin), under pH-cycling conditions, on the surface degradation of four composite resins (microhybrid: TPH, Concept, Opallis and Nanofilled: Supreme). Thirty disc-shaped specimens ([symbol: see text] = 5.0 mm/thickness = 2.0 mm) of each composite were randomly assigned to 3 groups (n = 10): a control and two experimental grou...