The application of organotypic cultures combined with gene expression profiling plus biochemical measurements characterizes the molecular mechanisms of drug action on the activation of cell death and survival pathways including oxidative stress arteria epigastrica cranialis superficialis commissura labiorum dorsalis cheap 75mg triamterene with mastercard, inflammation heart attack jaw quality 75 mg triamterene, apoptosis heart attack remixes 20 order discount triamterene, and repair blood pressure 300 150 purchase triamterene visa, with the goal to identify key pathways that are causal to organ dysfunction and injury. These advancements along with the increased application of human tissue models to define clinical relevance of potential side-effects and use of biomarkers redefines the scope of translational research in toxicology. The increased utilization of such models earlier to support drug candidate selection will add value to the safety decision process. Several examples will be presented which elucidate the mechanisms of drug-induced organ injury, define species sensitivities and susceptibility to organ injury, and aid in characterizing human response. One example, drug induced mitochondrial injury demonstrates the interplay of cells in liver slices by the induction of oxidative stress, increased apoptosis and inflammation. A second example is a hemolysis model, comprised of whole blood co-cultured with a liver slice, to evaluate time- and concentration-dependent toxicity on red blood cells. This example reveals that an oxidative stress response occurs in red blood cells prior to hemolysis, and that compound metabolism contributes to the outcome. A third example reveals that drug retention in thyroid is associated with inhibition of thyroid peroxidase function and potentially thyroid hormone synthesis. The toxicity of pharmaceutical compounds can be due to their interactions with unanticipated molecules in the body (off-target) or the direct consequence of overinhibiting or stimulating the intended molecular target in a desired or undesired location (target-based). Such complex processes of toxicity pose significant challenges to toxicologists who seek to either proactively minimize potential liabilities by devising screening strategies or to elucidate mechanistic understanding of an identified toxicity. The key to successfully implementing this approach is to anchor the data to traditional endpoints of interest, thus enabling a benchmarked relationship. Thus, it is important to implement strategies to obtain information early in the drug development process on potential safety risks, the challenges to evaluating predictivity, including in vitro/in vivo correlations, the need for increasing assay throughput, and general approaches to correlation/validation. Mitochondrial damage, oxidative stress, and intracellular glutathione, all measured by high content cellular imaging in primary human hepatocyte cultures, are the three most important features contributing to the hepatotoxicity prediction. Data integration is the process of combining data residing at different sources and providing the user with a unified view of these data. Taking advantage of multiple data sets has proven to be advantageous when approaching toxicological problems. Integration of divergent data sets collected on molecules in earlier stages of preclinical development is technically and scientifically challenging. These in vitro predictions can augment the performance of the combined traditional preclinical animal tests by identifying idiosyncratic human hepatotoxicants such as nimesulide, telithromycin, nefazodone, troglitazone, tetracycline, sulindac, zileuton, labetalol, diclofenac, chlorzoxazone, dantrolene, and many others. Early identification of toxicologic concerns can improve drug candidate quality and reduce cycle times. In a rat primary rat hepatocyte model, sparse linear programming-derived gene signatures are leveraged to predict in vivo toxicities. We have tested in the hepatocyte model more than 100 proprietary compounds with known outcomes for hepatic pathology in short term rat safety assessment studies. The analysis demonstrated acceptable performance metrics for prediction of in vivo outcomes. In addition, a specific example will be presented which illustrates the use of in vitro gene signatures to dissociate phospholipidosis from target organ toxicity within a series of highly structurally related compounds. Metabolomics, the global profiling of biochemicals, provides unparallel insight into the mechanistic action of drugs. Many of these biochemical changes are seen within hours of dosing, providing early-stage indication of drug safety issues. This presentation will demonstrate the utility of metabolomics in drug safety research through two case studies done in collaboration with leading pharmaceutical companies. Urine and kidney tissue samples were collected from groups of 6 rats each (12 rats for vehicle group) at days 1, 5 and 28. Full data curation of kidney tissue samples yielded 547 metabolites, and urine yielded 657 metabolites. Analysis of the metabolic changes showed Valproate stimulated fatty acid omega-oxidation, likely to compensate for a defective beta-oxidation. To better understand their mechanism of toxicity, rats were dosed with fen (300 mg/kg/day), or Pb (50 mg/kg/day) or vehicle. Potential cell proliferation biomarkers in plasma and urine were identified Their biochemical and physiological roles were related with liver and kidney malfunctions such as hyperplasia and cell proliferation. Sandwich-cultured mouse primary hepatocytes are an attractive model for toxicogenomics-based screening of chemicals to predict their toxicity. This is, because they are metabolically competent, the liver is frequently a target organ and mouse models gain in usage due to the development of transgenic models. Furthermore, mouse primary hepatocytes are favoured above rat hepatocytes, which are relatively unstable, as well as human hepatocytes, which are limited in availability. Therefore, we aim to develop in sandwich-cultured mouse primary hepatocytes transcriptomics-based prediction tools for the toxic properties of compounds, with the initial focus on specific classes of genotoxins and carcinogens. Time- and dose-dependent transcriptomics of benzo[a]pyrene exposed cells indicate that time has the biggest effect on the profiles, and that the modulation continuously increases over time (12-48h). Transcriptomics-based discrimination of genotoxic from non-genotoxic carcinogens was developed, showing that this was possible at various time points at 24h and 48h, but not at 12h, by Nearest Shrunken Centroids Analysis. Finally, the discrimination of true genotoxins from false-positive genotoxins was addressed at 24h and 48h. Currently, improvements are sought in the application of other supervised clustering algorithms and a mechanistic approach. The basic study design is to select multiple pairs of drugs with similar mechanisms of action where one contributed to cases of idiosyncratic liver injury in the clinical setting and the other has not - with both drugs being free of signs of liver toxicity in the preclinical environment. Drug pairs are evaluated in a 3-day and 28-day Sprague-Dawley rat model with multiple crossomics modalities.
The observation that cancer cells carry out aerobic glycolysis arrhythmia sinus bradycardia generic triamterene 75mg overnight delivery, converting glucose to lactate in the presence of oxygen blood pressure below 60 order 75 mg triamterene, was made in the 1920s and is called the Warburg effect arrhythmia test buy genuine triamterene line. This metabolic alteration differs from both anaerobic (without oxygen) glycolysis and aerobic metabolism used by differentiated cells that proceeds through the Krebs cycle and electron-transport chain (see box "A quick review about glucose metabolism") prehypertension hypertension purchase triamterene 75mg otc. This area of study has recently been revived, and differing viewpoints have not yet settled. It has been proposed that the metabolism of cancer cells resembles the metabolism of proliferating cells. Regardless of these different views, it is of interest that the Warburg effect is the basis for an important imaging technique used to detect tumors in the clinic. In this capacity, p53 acts as a metabolic checkpoint and induces cell cycle arrest in response to low cellular energy. Thus, mutations in p53 that drive cancer also cause altered metabolism that leads to the Warberg effect. Thus, the increased glycolysis observed in some tumors is regulated by a specific transcriptional program, rather than only a lack of oxygen. Rather, complex metabolic pathways such as those discussed earlier underlie the Warburg effect. Further investigations regarding the mechanism of this long-observed phenomenon are needed and may have additional therapeutic implications. A quick review of glucose metabolism In normal cells, the glycolysis pathway involves the breakdown of glucose in the absence of oxygen (anaerobic metabolism) and the production of pyruvate. These electron carriers shuttle their electrons through the electron transport chain located in the inner mitochondrial membrane. Enzyme activities may vary among individuals because of small variations, often single nucleotide changes, in the genes that code for them. The study of genetic polymorphisms that alter the response to a particular dietary constituent is called nutrigenetics. However, the polymorphism increases the risk of cancer if these individuals become deficient in folate. Polymorphisms in the gene that codes for N-acetyltransferase modify the risk of specific cancers in response to the consumption of red meat. This enzyme is involved in the metabolic activation of carcinogenic heterocyclic amines produced by cooking meat at high temperatures. Individuals with the "rapid variant" of the enzyme (a fast acetylator) who consume large amounts of red meat have an increased risk of colon cancer compared with those who have this variant and do not consume much red meat, or those who possess the "slow variant" polymorphism who do. Inherited metabolic diseases can illustrate a more obvious role of metabolism in carcinogenesis. Albinos have an inherited deficiency of the enzyme tyrosinase and are unable to produce melanin, causing the characteristic lack of pigment in their skin. The lack of pigment causes albinos to be more sensitive to the sun and results in an increased risk of skin carcinoma. Tyrosinemia type I, another disorder of tyrosine metabolism, results from a deficiency of fumarylacetoacetate hydrolase. As a result of this metabolic block, the metabolites fumarylacetoacetate and maleylacetate accumulate. In brief, tyrosinemia type I is characterized by the synthesis and accumulation of carcinogens. The pre-vitamin, regardless of its source (skin or diet), must be metabolized first in the liver to form 25-hydroxyvitamin D (biologically inert) and then in the kidney to form the biologically active form, 1,25-dihydroxyvitamin D. It has been proposed that vitamin D deficiency underlies this effect, although additional effects of sun exposure may also play a role. One study evaluated the growth of colon cancer cells in xenografts (human cells implanted in the backs of the immunodeficient mice) in vitamin D-deficient versus vitamin D-sufficient mice (Tangpricha et al. Tumors were 80% larger on average in mice that were deficient in vitamin D compared with vitamin D-sufficient mice. Collectively, epidemiological and in vivo evidence suggest a link between vitamin D deficiency and increased cancer risk. Over-fortification of milk caused an outbreak of vitamin D intoxication in Great Britain and led to regulations that ablated vitamin D fortification throughout Europe. As food analysis has become more reliable over the last 50 years, should vitamin D fortification be reconsidered in northern Europe and elsewhere The link between nutrients and gene expression became apparent upon the discovery that the receptors for vitamin A and D are members of the steroid hormone receptor superfamily. The active form of vitamin D (1,25-hydroxyvitamin D) acts as a ligand for the cytoplasmic vitamin D receptor, a member of the steroid hormone receptor superfamily. This receptor recognizes the vitamin D response element in gene promoter regions and regulates transcription of its target genes. Current data suggest that vitamin D is a chemopreventative agent that inhibits growth and induces differentiation and apoptosis through several molecular targets. You may recall that the p21 protein is an inhibitor of cyclin-dependent kinase and that it can induce cell cycle arrest. Vitamin D promotes apoptosis through mitochondrial signaling independent of caspase activation. These two proteins form channels in the mitochondrial membrane and facilitate the release of cytochrome c and apoptosome assembly (see Chapter 7). The hormone-related cancers include breast, endometrium, ovary, prostate, testis, and thyroid cancer.
Humans are exposed to methylmercury through consumption of fish blood pressure after exercise cheap 75 mg triamterene amex, and inorganic mercury through occupational exposures and dental amalgams arrhythmia tachycardia purchase cheapest triamterene and triamterene. While the toxicity of mercury is well established blood pressure up and down cheap triamterene 75 mg with amex, much remains to be elucidated about the mechanisms of mercury toxicity yaz arrhythmia triamterene 75mg mastercard. In particular, little is known about the extent to which different species of mercury behave similarly or differently at the cellular level. In order to address this issue, we employed a toxicogenomics approach using the nematode Caenorhabditis elegans. Analysis of the microarray data using principal components analysis, hierarchical clustering, and self-organizing maps indicated that C. Additionally, comparison of significantly enriched Gene Ontologies found no overlap between low-toxic exposures, and only a ~20% overlap between high-toxic exposures. These data indicate that there are large differences in the manner in which different species of mercury affect the cell. However, few studies have evaluated associations between low-level cadmium and clinical renal outcomes, particularly with respect to joint cadmium and lead. The odds ratios comparing participants in the highest quartile of both metals to those in the lowest quartile of both metals were 2. Cadmium is an environmental toxin present in industrial wastes, road and house dust, and food crops grown in cadmium-polluted soil. We hypothesized that cadmium could induce fetal growth restriction and placental insufficiency through a reduction of placental blood vessels and reduction of blood flow through the umbilical artery. Methods: Cadmium chloride (40ppm) was administered via drinking water to female C57Bl/6 mice from 2-4 weeks prior to conception. Due to the reduction of successful pregnancies, the treatment was adjusted to 20ppm starting at day 1 until E15 of pregnancy. Umbilical artery blood velocity was assessed on E15 via ultrasound using the Doppler pulse method before euthanasia. Results: Mice treated with cadmium chloride demonstrated a significant reduction of umbilical artery velocity with control mice having 59. Our earlier studies found supportive evidence for a tumorigenic effect of carcinogenic metal-containing welding fume in A/J mice. This genetic disparity provides a unique scenario to identify molecular mechanisms associated with the lung response to welding fume at the transcriptome level. Mice were necropsied 28 days after the last exposure and whole lung microarray using Illumina Mouse Ref-8 expression beadchips was done. In contrast, the connective tissue disorders, immunological disease, inflammatory disease network was most significant in the B6 strain. In the A/J, 75% of the focus molecules that met the cutoff were up-regulated as compared to 40% in the B6. Genes regulating cellular movement, hematological system development and function, and immune response were most involved in the B6 response. Of the significant focus molecules, 88% were up-regulated in the A/J compared to 45% in the B6. Overall, these data confirm our previous observation that strain-dependent differences in response to welding fume occur in the A/J and B6 lung. Also, in contrast to the B6, the A/J strain exhibited a persistent up-regulation of welding fume-induced gene transcription suggesting that chronic lung cell activation may play a role in the tumorigenic effects of welding fume. Millions of American workers are exposed to cobalt, primarily through inhalation, leading to several disorders including respiratory tract hyperplasia, fibrosis, and asthma. Obesity is the single most important risk factor for the development of insulin resistance and type 2 diabetes. However, chronic exposures to inorganic arsenic (iAs) have also been associated with an increased prevalence of type 2 diabetes mellitus. At 20 weeks fasting blood samples were collected and oral glucose tolerance tests were administered to all mice. It has been reported that vanadium pentoxide (V2O5) exposure produces cytotoxic effects such as genotoxicity, cell cycle modifications, apoptosis, as well as structural and functional cytoskeleton alterations. Vanadium adverse effects help to explain its potential in producing pathologies such as cancer. Previously our laboratory observed that vanadium pentoxide inhalation induced nuclear morphological changes in lymphocyte similar to those found in neoplastic cells. Owing to the fact that nuclear lamins keep nuclear structure and function integrity, and have been also associated with neoplastic transformation, we investigated the alterations in nuclear B1lamin from spleen lymphocytes after vanadium pentoxide inhalation. Changes in nuclear B1-lamin concentration in lymphocytes subpopulations were evaluated by flow cytometry. Our findings explain the morphological nuclear changes observed previously in our laboratory. Additionally, these results help to elucidate the potential carcinogenic effect of vanadium pentoxide due to the decrease in nuclear lamins, as it has been observed in cancer. This underestimates a host of costs related to the inequities of Pb poisoning because it excludes the social stresses from excessive violence and the extraordinary price of the justice and prison system. Exposure to Cd results in: oxidative stress, disruption of cell adhesion molecules and alterations in cell cycle control. Although some of the generalized cellular responses to Cd-induced injury are well known; other cellular responses are just now being elucidated.
These findings indicate that inhalation exposure to C60 particles caused negligible toxicity and that a decrease in particle size to the nanoscale did not exacerbate toxicity arteria auricular posterior order genuine triamterene on-line. These data are consistent with the observed lack of toxicity of C60 after both shorter-term exposures and in studies using intratracheal instillation prehypertension 38 weeks 75mg triamterene visa. Nanoscale engineering represents a current dynamic area of interdisciplinary research incorporating nanoparticles into a diverse product matrix hypertension and exercise cheap 75 mg triamterene with mastercard. Nanoparticle size hypertension 38 weeks pregnant discount 75 mg triamterene, surface functionalization, and chemical composition are but three critical nanotoxic metrics. Zebrafish (Danio rerio) embryo exposures with non-functionalized, colloidal silver (cAg) and gold nanoparticles (cAu) in an array of sizes (3, 10, 50, and 100 nm) produced a range of toxic effects. Using a semi-quantitative scoring system, cAg3, 10, 50, and 100 elicited nearly 100% embryonic mortality 120 h post-fertilization (hpf); cAu3, 10, 50, and 100 exposures resulted in less than 3% mortality 120 hpf. While cAu induced minimal sublethal toxic effects, cAg exposures generated various embryonic and morphological malformations including stunted growth, opaque and non-depleted yolks, circulatory malformations, and jaw defects amongst others at 120 hpf. Both cAg and cAu were taken up by the embryos and results from vector control experiments suggest cAg sublethal toxicity and mortality were a result of the nanoparticles themselves or Ag+ ions formed either during in vivo nanoparticle destabilization or as a residual synthetic contaminant. Although cAg toxicity was size-dependent at specific concentrations and time points, the most striking result is that parallel sizes of cAg and cAu induced significantly divergent toxic profiles, with the former being toxic and the latter inert at all sizes tested. Thus, we propose that nanoparticle chemistry is as, if not more, important than specific nanosizes at inducing toxicity in vivo. Ultimately, nanotoxicity assessments using the zebrafish embryo model should identify nanomaterial physicochemical characteristics that yield minimal or no toxicity for improved rational designs of nanomaterials. No significant elevations in Ti levels were observed in all the organs analyzed for the three different TiO2 formulations when applied to intact and dermabraded skin. The results suggest that both intact and compromised skin of hairless mice may be an effective barrier in preventing dermal penetration and subsequent organ bioaccumulation of topically applied nano-and micron-sized TiO2 of different surface coatings. The objectives of this study were to investigate the effects of cerium oxide on the pulmonary immune/inflammatory responses. In an effort to test nanoparticles in vivo while minimizing the number of rabbits used, nine nanoparticles were placed on the backs of 4 rabbits to determine if they cause skin irritation. The study followed the Environmental Protection Agency Health Effects Test Guidelines, Office of Prevention, Pesticides and Toxic Substances 870. We determined the ideal number of sites when placing Hilltop Chambers on the skin is 8 sites per rabbit. Each of the 4 rabbits had at least one negative control site with a Hilltop Chamber only and seven sites with nanoparticles (six for one rabbit with two negative controls). Each nanoparticle site on each rabbit was a different nanoparticle so that each nanoparticle was still placed on 3 different rabbits. Dermal transport and possible toxicity of nanoscale metal oxides used in cosmetic and personal care products are relatively unexplored and is the focus of this study. We also demonstrated that following intradermal injection, the biodistribution of three different types of TiO2, uncoated nano, coated nano and micron, depended upon the size and coating properties. In that study an increase in titanium (Ti) in liver accounted for ~10% of injected dose of all three TiO2, in lymph nodes the Ti accounted for ~1% of injected dose seen with coated nano and micron TiO2, and Ti accumulated in kidneys exclusively with micron TiO2 (~16% of dose). In the present study, emulsions containing 5% of either nanoscale (25 nm primary particle size) uncoated anatase TiO2, micronscale anatase TiO2 and nanoscale (14 x 79 nm rods) polystearate/alumina-coated TiO2 were topically applied to intact dorsal or inguinal and axillary regions or to dermabraded skin of hairless mice. The integration of gene expression with organism and population level endpoints was investigated using C. Significant decreases in reproduction parameter concomitantly occurred in silver nanoparticle exposed C. Overall results of functional genomic using mutant analysis suggested that the sod-3 and daf-12 genes may be related to silver nanoparticle -induced reproductive failure in C. This study also suggested that the interpretation of microarray and subsequent quantitative gene expression data was greatly strengthened by linking them with organism and population level experiments and functional genomics using mutant strains appears to be an ideal tool for biomarker discovery in toxicological research as it can reveal the physiological meaning or function of observed altered gene expressions. Acknowledgment: this work was accomplished through the supports of the Ministry of Environment as "The Eco-technopia 21 project" diction suggested that compared to microspheres, the 40 and 20 nm spheres had a reduced distribution to the spleen and bone marrow and an increased distribution to the brain. However, it is unclear whether the slight increase in distribution to the brain for the small particles is real because the particle concentration in brain samples was near or below the limit of detection (<0. The resulting model fit well for 100nm spheres, but was inadequate for 40 and 20nm spheres, for which further modifications of model structure may be needed. A comparison of model parameters optimized specifically for each sized particle indicated that the smaller particles tend to stay longer in blood circulation. Regardless of particle size, the estimated partition coefficients are always high for spleen and liver, but low for brain, suggesting a common kinetic mechanism of these particles in major organs. However, there is evidence that once deposition occurs, these particles can escape clearance mechanisms and target secondary organs like the brain. The three regions were collected 1w, 3m, and 5m, post exposure (24h) for gene expression analyses (n=4/group). After 1w of exposure, the expression of approximately 50 oxidative stress and inflammation related genes were altered in all regions. Following 3 and 5m of exposure, more changes in gene expression were observed in the olfactory bulb (85 and 72, respectively) followed by the cerebellum (35 and 45, respectively) and the midbrain (21 and 28, respectively). Additional studies are needed to link the changes in gene expression to mechanisms of toxicity. Nanoparticles are increasingly used in a wide range of applications, and may have a higher toxic potential than similar particles of larger sizes. Nanoparticles can induce inflammatory reactions in the lung and may thus interfere with existing allergic inflammation. The allergic rats exhibited an altered breathing pattern (apnoeas), and a slightly increased breathing frequency during challenge, allergic laryngitis and increased granulomatous inflammation in the lungs. Exposure to nanoparticle aggregates and fine particles induced accumulation of black particles in the larynx, lungs and mediastinal lymph nodes.
