Morphological and molecular course of mitochondrial pathology in cultured human cells exposed long-term to Zidovudine.

Long-term use of antiretroviral nucleoside reverse transcriptase inhibitors (NRTIs) as therapy for human immunodeficiency virus-1 (HIV-1) infection is limited by mitochondrial toxicity. Here we document mitochondrial pathology during the long-term culture of human HeLa cells in the presence or absence of the NRTI Zidovudine(R) (AZT, 800 muM) for up to 77-passages (p), with samples taken at early (p5-p11), middle (p36 and p37), and late (p70-p77) passages. Samples were analyzed for changes in mitochondrial morphology, mitochondrial (mt)DNA quantity, nuclear and mitochondrial gene expression, and mitochondrial membrane potential. Mitochondria showed abnormal proliferation at p5 and abnormal morphology >/=p36. mtDNA quantity was increased at p5 and p11, and 65% depleted at p71. Hierarchical clustering of nuclear gene expression, examined at p37 by the NCI cDNA microarray in AZT-exposed cells, showed down-regulation of 13 out of 16 lipid-metabolizing genes, and up-regulation of most oxidative phosphorylation (OXPHOS) genes. OXPHOS genes encoded by mtDNA, examined at p5, p36, and p75 using the Mitochondrial Gene Mini Array, revealed up-regulation of genes coding for polypeptides of NADH dehydrogenase, ATP synthase, and cytochrome c oxidase. Mitochondrial membrane potential, monitored by JC1 staining, was elevated at p10 and p32, and essentially completely absent at p71. The data show that during chronic exposure of HeLa cells to AZT, a compensatory response was induced at the earlier passages (p5-p37), and by p71 there was widespread mitochondrial morphological damage, severe mtDNA depletion, and a substantial loss of mitochondrial membrane potential.

Transcriptional signatures of normal human mammary epithelial cells in response to benzo[a]pyrene exposure: a comparison of three microarray platforms.

Microarrays are used to study gene expression in a variety of biological systems. A number of different platforms have been developed, but few studies exist that have directly compared the performance of one platform with another. The goal of this study was to determine array variation by analyzing the same RNA samples with three different array platforms. Using gene expression responses to benzo[a]pyrene exposure in normal human mammary epithelial cells (NHMECs), we compared the results of gene expression profiling using three microarray platforms: photolithographic oligonucleotide arrays (Affymetrix), spotted oligonucleotide arrays (Amersham), and spotted cDNA arrays (NCI). While most previous reports comparing microarrays have analyzed pre-existing data from different platforms, this comparison study used the same sample assayed on all three platforms, allowing for analysis of variation from each array platform. In general, poor correlation was found with corresponding measurements from each platform. Each platform yielded different gene expression profiles, suggesting that while microarray analysis is a useful discovery tool, further validation is needed to extrapolate results for broad use of the data. Also, microarray variability needs to be taken into consideration, not only in the data analysis but also in specific probe selection for each array type.

Lidocaine pretreatment with tourniquet versus lidocaine-propofol admixture for attenuating propofol injection pain: a randomized controlled trial.

OBJECTIVE: Findings from studies investigating optimal techniques for attenuating propofol-related injection pain are inconsistent. In previous studies, lidocaine pretreatment using a tourniquet has been reported to be superior, inferior, or equivalent to a lidocaine-propofol admixture for reducing pain. This discordance could represent either no meaningful difference in the treatments or underlying methodological differences in the previous studies. We hypothesized that tourniquet-controlled pretreatment with lidocaine would be superior to lidocaine-propofol admixture for reducing propofol injection pain. METHODS: This randomized controlled trial compared 3 groups-a control group (saline pretreatment/saline admixture; n = 50), a pretreatment group (lidocaine pretreatment/saline admixture; n = 51), and an admixture group (saline pretreatment/lidocaine admixture; n = 50). The primary outcome was verbal pain score after injection. The incidence of pain on injection was explored as a secondary outcome. RESULTS: The median (interquartile range) verbal pain score after study solution injection were as follows-control group: 3 (0-6), pretreatment group: 0 (0-0), and admixture group: 0 (0-2). The pretreatment group had significantly lower pain scores when compared with the admixture group (P = 0.016), and both groups were superior to the control group. The pretreatment group had fewer subjects experiencing any injection pain than did the admixture group (20% vs. 44%, respectively; P = 0.024). CONCLUSIONS: Tourniquet-controlled pretreatment with lidocaine is statistically superior to admixing lidocaine with propofol for reducing propofol injection pain intensity, but the clinical importance of this small effect is questionable. However, pretreatment more effectively eliminates injection pain.