Studies were undertaken to investigate acquired resistance to cisplatin in human ovarian cancer cells. The cell lines A2780 and A2780/CP70 were studied to assess their respective characteristics of ...drug accumulation and efflux, cytosolic inactivation of drug, and DNA repair. All experiments were performed using 1-h drug exposures. The A2780/CP70 cell line was 13-fold more resistant to cisplatin than A2780 cells. When studied at their respective IC50 doses, drug accumulation rates were similar for the two cell lines. However, the resistant cell line was twofold more efficient at effluxing drug, which was associated with reduced total drug accumulation for equivalent micromolar drug exposures. At equivalent levels of total cellular drug accumulation, the two cell lines formed the same levels of cisplatin-DNA damage, suggesting that cytosolic inactivation of drug does not contribute to the differential in resistance between these cell lines. Resistant cells were also twofold more efficient at repairing cisplatin-DNA lesions in cellular DNA and in transfected plasmid DNA. We conclude that in these paired cell lines, alterations in drug uptake/efflux and in DNA repair are the major contributing factors to acquired resistance to cisplatin.
Acute cytotoxicity (lactate dehydrogenase release) of trichloroethylene (TRI), S-(1,2-dichlorovinyl)glutathione (DCVG), and S-(1,2-dichlorovinyl)-L-cysteine (DCVC) in freshly isolated renal cortical ...cells and hepatocytes from male and female rats was evaluated to test the hypothesis that the assay provides a valid indicator of sex- and tissue-dependent differences in sensitivity to TRI and its metabolites. We then determined mitochondrial toxicity (inhibition of state-3 and/or stimulation of state-4 respiration) in renal cortical and hepatic mitochondria from male and female rats and mice to assess sex-, tissue-, and species-dependent susceptibility. TRI was moderately cytotoxic in renal cells from male rats but was nontoxic in renal cells from female rats or hepatocytes from male or female rats. Acute cytotoxicity of both DCVG and DCVC was greater in renal cells from male rats than in renal cells from female rats. Although DCVC does not target the liver in vivo, it was a very potent hepatotoxicant in vitro. Mitochondrial toxicity in kidney and liver showed similar patterns, with mitochondria from male rats being more sensitive than mitochondria from female rats; order of potency was DCVC > DCVG >> TRI. State-3 respiration in mitochondria from mice was also inhibited, but the patterns and relative sensitivities differed from those in mitochondria from rats. Renal and hepatic mitochondria from mice were less sensitive than corresponding mitochondria from rats and renal mitochondria from female mice were significantly more sensitive than renal mitochondria from male mice. Thus, many of the species-, sex-, and tissue-dependent differences in toxicity observed in vivo are also observed in vitro.
Single nucleotide polymorphisms (SNPs) in the estrogen receptor 1 (ESR1) and cytochrome P450 19A1 (CYP19A1) genes have been associated with breast cancer risk, endocrine therapy response and side ...effects, mainly in postmenopausal women with early breast cancer. This analysis aimed to assess the association of selected germline CYP19A1 and ESR1 SNPs with early-onset hot flashes, sweating and musculoskeletal symptoms in premenopausal patients enrolled in the Tamoxifen and Exemestane Trial (TEXT).
Blood was collected from consenting premenopausal women with hormone-responsive early breast cancer, randomly assigned to 5-years of tamoxifen plus ovarian suppression (OFS) or exemestane plus OFS. DNA was extracted with QIAamp kits and genotyped for two CYP19A1 (rs4646 and rs10046) and three ESR1 (rs2077647, rs2234693 and rs9340799) SNPs by a real-time pyrosequencing technique. Adverse events (AEs) were recorded at baseline and 3-monthly during the first year. Associations of the genotype variants with grade ≥2 early-onset targeted AEs of hot flashes/sweating or musculoskeletal events were assessed using logistic regression models.
There were 2660 premenopausal patients with breast cancer in the intention-to-treat population of TEXT, and 1967 (74 %) are included in this translational study. The CYP19A1 rs10046 variant T/T, represented in 23 % of women, was associated with a reduced incidence of grade ≥2 hot flashes/sweating (univariate odds ratio (OR) = 0.78; 95 % CI 0.63-0.97; P = 0.03), more strongly in patients assigned exemestane + OFS (TT vs CT/CC: OR = 0.65, 95 % CI = 0.48-0.89) than assigned tamoxifen + OFS (OR = 0.94, 95 % CI = 0.69-1.27, interaction P = 0.03). No association with any of the CYP19A1/ESR1 genotypes and musculoskeletal AEs was found.
The CYP19A1 rs10046 variant T/T favors lower incidence of hot flashes/sweating under exemestane + OFS treatment, suggesting endocrine-mediated effects. Based on findings from others, this SNP may potentially enhance treatment adherence and treatment efficacy. We plan to evaluate the clinical impact of this polymorphism during time, pending sufficient median follow up.
ClinicalTrials.gov NCT00066703, registered August 6, 2003.
Reduced lung function predicts mortality and is key to the diagnosis of chronic obstructive pulmonary disease (COPD). In a genome-wide association study in 400,102 individuals of European ancestry, ...we define 279 lung function signals, 139 of which are new. In combination, these variants strongly predict COPD in independent populations. Furthermore, the combined effect of these variants showed generalizability across smokers and never smokers, and across ancestral groups. We highlight biological pathways, known and potential drug targets for COPD and, in phenome-wide association studies, autoimmune-related and other pleiotropic effects of lung function-associated variants. This new genetic evidence has potential to improve future preventive and therapeutic strategies for COPD.
The effect of solids retention time (SRT) on ammonia- and nitrite-oxidizing bacteria was measured by Nitrosomonas oligotropha-like ammonia monooxygenase A and Nitrospira 16S rDNA competitive ...polymerase chain reaction assays in a complete-mix, bench-scale, activated-sludge system. During steady-state operation, nitrification was complete in the 20- and 10-day SRT reactors, nearly complete in the 5-day SRT reactor, and incomplete in the 2-day SRT reactor (76% ammonia oxidation and 85% nitrite oxidation). Total microbes, measured by dot-blot hybridizations, ranged from$3\times 10^{11}$to$3\times 10^{12}$cells/L, and increased with increasing SRTs. The concentration of the ammonia-oxidizer N. oligotropha dropped 100-fold from the 20-day SRT ($5\times 10^{9}$cells/L) to the 2-day SRT ($\leq 4\times 10^{7}$cells/L). Thus, N. oligotropha became a much smaller fraction of the total biomass in the poorly performing 2-day SRT reactor. The concentration of Nitrospira cells also decreased (10-fold) as the SRT was reduced from 20 days to 2 days. However, the number of Nitrospira cells was always greater than the number of N. oligotropha cells measured in each reactor (10- to 60-fold). While Nitrospira comprised 1 to 2% of the biomass, N. oligotropha represented only 0.04 to 0.27% of the total population. This low percentage suggests that N. oligotropha was not a dominant ammonia oxidizer in the bench-scale systems.
Most solid tumors are characterized by a metabolic shift from glucose oxidation to glycolysis, in part due to actively suppressed mitochondrial function, a state that favors resistance to apoptosis. ...Suppressed mitochondrial function may also contribute to the activation of hypoxia-inducible factor 1a (HIF1α) and angiogenesis. We have previously shown that the inhibitor of pyruvate dehydrogenase kinase (PDK) dichloroacetate (DCA) activates glucose oxidation and induces apoptosis in cancer cells in vitro and in vivo. We hypothesized that DCA will also reverse the 'pseudohypoxic' mitochondrial signals that lead to HIF1α activation in cancer, even in the absence of hypoxia and inhibit cancer angiogenesis. We show that inhibition of PDKII inhibits HIF1α in cancer cells using several techniques, including HIF1α luciferase reporter assays. Using pharmacologic and molecular approaches that suppress the prolyl-hydroxylase (PHD)-mediated inhibition of HIF1α, we show that DCA inhibits HIF1a by both a PHD-dependent mechanism (that involves a DCA-induced increase in the production of mitochondria-derived a-ketoglutarate) and a PHD-independent mechanism, involving activation of p53 via mitochondrial-derived H.sup.2O.sub.2, as well as activation of GSK3p. Effective inhibition of HIF1α is shown by a decrease in the expression of several HIF1α regulated gene products as well as inhibition of angiogenesis in vitro in matrigel assays. More importantly, in rat xenotransplant models of non-small cell lung cancer and breast cancer, we show effective inhibition of angiogenesis and tumor perfusion in vivo, assessed by contrast-enhanced ultrasonography, nuclear imaging techniques and histology. This work suggests that mitochondria-targeting metabolic modulators that increase pyruvate dehydrogenase activity, in addition to the recently described pro-apoptotic and anti-proliferative effects, suppress angiogenesis as well, normalizing the pseudo-hypoxic signals that lead to normoxic HIF1α activation in solid tumors. Oncogene (2013) 32, 1638-1650; doi:10.1038/onc.2012.198; published online 21 May 2012 Keywords: mitochondria; angiogenesis; hypoxia-inducible-factor; stem cell; tumor perfusion; vascularity
Blob-filaments (or simply 'blobs') are coherent structures formed by turbulence and sustained by nonlinear processes in the edge and scrape-off layer (SOL) of tokamaks and other magnetically confined ...plasmas. The dynamics of these blob-filaments, in particular their radial motion, can influence the scrape-off layer width and plasma interactions with both the divertor target and with the main chamber walls. Motivated by recent results from the XGC1 gyrokinetic simulation code reported on elsewhere J. Cheng et al. submitted to Nucl. Fusion and available at arXiv:2302.02877v1, a theory of rapidly spinning blob-filaments has been developed. The theory treats blob filaments in the closed flux surface region or the region that is disconnected from sheaths in the SOL. It extends previous work by treating blob spin, arising from partially or fully adiabatic electrons, as the leading order effect and retaining inertial (ion charge polarization) physics in next order. Spin helps to maintain blob coherency and affects the blob's propagation speed. Dipole charge polarization, treated perturbatively, gives rise to blob-filaments with relatively slow radial velocity, comparable to that observed in the simulations. The theory also treats the interaction of rapidly spinning blob filaments with a zonal flow layer. It is shown analytically that the flow layer can act like a transport barrier for these structures. Finally parallel electron kinetic effects are incorporated into the theory. Various asymptotic parameter regimes are discussed and asymptotic expressions for the radial and poloidal motion of the blob-filaments are obtained.
The thresholding method involves first locating objects in an image by using the intensity gradient, then noting the levels that correspond to the objects in various areas of the image, and finally ...using these levels as initial guesses at a threshold. This method is capable of thresholding images that have been produced in the context of variable illumination. The thresholding method, called the local intensity gradient (LIG) method, was implemented in C using a Sun4 host running UNIX. The LIG method was compared against iterative selection (IS), gray level histograms (GLHs) and two correlation based algorithms on a dozen sample images under three different illumination effects. Overall, the LIG method, while it takes significantly longer, properly thresholds a larger set of images than does any other method examined over the sample images tested.< >
PURPOSE.Results of a study of associations between visual acuity and the risk of misuse of nonprescription acetaminophen products in a sample of community-dwelling adults are reported.
METHODS.In a ...study involving English-speaking adults at 4 primary care clinics, the potential for misuse of nonprescription acetaminophen products was measured via a functional assessment of product self-dosing and by testing patients’ understanding of the risks of concomitant use (i.e., taking 2 products at the same time when contraindicated). Vision was assessed using the Rosenbaum vision chart and dichotomized as normal (visual acuity of 20/20–20/25) or low (acuity of 20/30–20/100). Bivariable and multivariable analyses were performed to determine the impact of visual acuity on medication misuse outcomes.
RESULTS.Among the study participants (n = 500), 39% had limited literacy, and 54% were categorized as having low vision. After controlling for age, race, and prior acetaminophen use, low vision was independently associated with an increased risk of self-dosing errors (odds ratio OR, 1.67; 95% confidence interval CI, 1.25–2.21; p < 0.001) and misunderstanding of concomitant-use risks (OR, 1.41; 95% CI, 1.00–2.00; p = 0.05). Limited literacy was an independent risk factor for incorrect dosing (OR, 1.71; 95% CI, 1.25–2.35; p = 0.001) and unawareness of concomitant use instructions (OR, 4.14; 95% CI, 2.80–6.12; p < 0.001).
CONCLUSION.Misunderstanding of nonprescription acetaminophen product information was common among study participants and independently associated with both impaired visual acuity and low literacy skills.
PDF
