Am J Physiol Renal Physiol
December 2008
Interstitial cystitis (IC) is a chronic and painful bladder syndrome of unknown cause with no reliable biological marker or effective therapy. Vascular endothelial growth factor (VEGF), which plays a key role in bladder inflammation, is closely associated with the vascular alterations observed in patients with IC. However, our recent findings of VEGF receptors (VEGF-Rs) and VEGF coreceptors on nonendothelial cells in human and mouse urothelium suggest that additional VEGF targets and functions are possible in IC bladders.
View Article and Find Full Text PDFPosttranslational modification by ubiquitination marks defective or outlived intracellular proteins for proteolytic degradation by the 26S proteasome. The ATP-dependent, covalent ligation and formation of polyubiquitin chains on substrate proteins requires the presence and activity of a set of ubiquitin activating and conjugating enzymes. While protein ubiquitination typically occurs in the cell cytosol or nucleus, defective mammalian spermatozoa become ubiquitinated on their surface during post-testicular sperm maturation in the epididymis, suggesting an active molecular mechanism for sperm quality control.
View Article and Find Full Text PDFAssessment of dopamine nerve terminal function and integrity is a strategy employed to monitor deficits in Parkinson's disease (PD) patients and in preclinical models of PD. Dopamine replacement therapies effectively replenish the diminished supply of endogenous dopamine and provide symptomatic benefit to patients. Tyrosine hydroxylase (TH), dopamine transporter (DAT), vesicular monoamine transporter 2 (VMAT2), and amino acid decarboxylase (AADC) are widely used markers of dopaminergic neurons and terminals.
View Article and Find Full Text PDFActin filaments play a critical role in the normal physiology of lenticular and retinal cells in the eye. Disruption of the actin cytoskeleton has been associated with retinal pathology and lens cataract formation. Ocular toxicity is an infrequent observation in drug safety studies, yet its impact to the drug development process is significant.
View Article and Find Full Text PDFTheophylline (THP) and 1,3-dinitrobenzene (DNB) are thought to induce infertility by incapacitating the nurturing Sertoli cells and causing germ cell apoptosis in the testicular seminiferous epithelium, respectively. We hypothesized that THP and DNB exposure would alter the expression of the genes within the ubiquitin-proteasome pathway (UPP), implicated in spermatogenesis and epididymal sperm quality control. Rats were fed 0 or 8000 ppm of THP and necropsied on Days 18, 30, and 42 or administered 0, 2, or 6 mg/kg DNB via oral gavage and necropsied on Day 7.
View Article and Find Full Text PDFPurpose: The insulin-like growth factor (IGF) signaling pathway is implicated in cellular mitogenesis, angiogenesis, tumor cell survival, and tumorigenesis. Inhibition of this pathway results in decreased cell growth, inhibition of tumor formation in animal models, and increased apoptosis in cells treated with cytotoxic chemotherapy. We generated and characterized a human monoclonal antibody that targeted the IGF receptor.
View Article and Find Full Text PDFPentamidine, an antiprotozoal agent, has been traditionally known to cause QT prolongation and arrhythmias; however, its ionic mechanism has not been illustrated. In a stable HEK-293 cell line, we observed a concentration-dependent inhibition of the hERG current with an IC50 of 252 microM. In freshly isolated guinea-pig ventricular myocytes, pentamidine showed no effect on the L-type calcium current at concentrations up to 300 microM, with a slight prolongation of the action potential duration at this concentration.
View Article and Find Full Text PDFThis study aims to compare the integrity and reproducibility of measurements created from uncompressed and compressed digital images in order to implement compliance with 21 CFR Part 11 for image analysis studies executed using 21 CFR Part 58 compliant capture systems. Images of a 400-mesh electron microscope grid and H&E stained rat liver tissue were captured on an upright microscope with digital camera using commercially available analysis software. Digital images were stored as either uncompressed TIFFs or in one of five different levels of JPEG compression.
View Article and Find Full Text PDFHepatic steatosis, or fatty liver, is commonly observed during the animal phase of drug safety studies. A noninvasive three-dimensional (3D) three-point Dixon method was used to quantitatively evaluate the fatty livers of rats induced by an experimental microsomal transfer protein (MTP) inhibitor, in an effort to develop a safety biomarker that could be translated to human studies. The method was implemented at 2.
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