Home About us Contact
|
Home About us Contact | ||
|
|
||
Significant Induction (significant + induction)
Selected AbstractsGenotoxicity of nitrosulfonic acids, nitrobenzoic acids, and nitrobenzylalcohols, pollutants commonly found in ground water near ammunition facilitiesENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2006Tamara Grummt Abstract 2-Amino-4,6-dinitrobenzoic acid (2-A-4,6-DNBA), 4-amino-2,6-dinitrobenzoic acid (4-A-2,6-DNBA), 2,4,6-trinitrobenzoic acid (2,4,6-TNBA), 2-amino-4, 6-dinitrobenzylalcohol (2-A-4,6-DNBAlc), 4-amino-2,6-dinitrobenzylalcohol (4-A-2,6-DNBAlc), 2,4-dinitrotoluol-5-sulfonic acid (2,4-DNT-5-SA), 2,4-dinitrotoluol-3-sulfonic acid (2,4-DNT-3-SA), and 2, 4-dinitrobenzoic acid (2,4-DNBA) are derivatives of nitro-explosives that have been detected in groundwater close to munitions facilities. In the present study, the genotoxicity of these compounds was evaluated in Salmonella/microsome assays (in strains TA100 and TA98, with and without S9 and in TA98NR without S9), in chromosomal aberration (CA) tests with Chinese hamster fibroblasts (V79), and in micronucleus (MN) assays with human hepatoma (HepG2) cells. All compounds except the sulfonic acids were positive in the bacterial mutagenicity tests, with 2,4,6-TNBA producing the strongest response (8023 revertants/,mol in TA98 without S9 activation). 2-A-4,6-DNBA was a direct acting mutagen in TA98, but negative in TA100. The other positive compounds were ,1,3 orders of magnitude less mutagenic than 2,4,6-TNBA in TA98 and in TA100; relatively strong effects (,50,400 revertants/,mol) were produced by the benzylacohols in the two indicator strains. With the exception of 2,4-DNBA, the mutagenic responses were lower in the nitroreductase-deficient strain TA98NR than in the parental strain. 2,4-DNBA produced a marginally positive response in the V79-cell CA assay; the other substances were devoid of activity. Only the benzoic acids were tested for MN induction in HepG2 cells, and all produced positive responses. As in the bacterial assays, the strongest effect was seen with 2,4,6-TNBA (significant induction at ,1.9 ,M). 4-A-2,6-DNBA was positive at 432 ,M; the weakest effect was observed with 2,4,-DNBA (positive at ,920 ,M). The differences in the sensitivity of the indicator cells to these agents can be explained by differences in the activities of enzymes involved in the activation of the compounds. The strong responses produced by some of the compounds in the human-derived cells suggest that environmental exposure to these breakdown products of nitro-explosives may pose a cancer risk in man. Environ. Mol. Mutagen., 2006. © 2005 Wiley-Liss, Inc. [source] Comparative mechanisms of zearalenone and ochratoxin A toxicities on cultured HepG2 cells: Is oxidative stress a common process?ENVIRONMENTAL TOXICOLOGY, Issue 6 2009Emna El Golli Bennour Abstract Zearalenone (ZEN) and Ochratoxin A (OTA) are structurally diverse fungal metabolites that can contaminate feed and foodstuff and can cause serious health problems for animals as well as for humans. In this study, we get further insight of the molecular aspects of ZEN and OTA toxicities in cultured human HepG2 hepatocytes. In this context, we have monitored the effects of ZEN and OTA on (i) cell viability, (ii) heat shock protein (Hsp) 70 and Hsp 27 gene expressions as a parameter of protective and adaptive response, (iii) oxidative damage, and (iv) cell death pathways. Our results clearly showed that both ZEN and OTA inhibit cell proliferation. For ZEN, a significant induction of Hsp 70 and Hsp 27 was observed. In the same conditions, ZEN generated an important amount of reactive oxygen species (ROS). Antioxidant supplements restored the major part of cell mortality induced by ZEN. However, OTA treatment downregulated Hsp 70 and Hsp 27 protein and mRNA levels and did not induce ROS generation. Antioxidant supplements did not have a significant effect on OTA-induced cell mortality. Using another cell system (Vero monkey kidney cells), we demonstrated that OTA downregulates three members of HSP 70 family: Hsp 70, Hsp 75, and Hsp 78. Our findings showed that oxidative damage seemed to be the predominant toxic effect for ZEN, while OTA toxicity seemed to be rather because of the absence of Hsps protective response. Furthermore, the two mycotoxins induced an apoptotic cell death. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source] Pulmonary responses of acute exposure to ultrafine iron particles in healthy adult ratsENVIRONMENTAL TOXICOLOGY, Issue 4 2003Ya-Mei Zhou Abstract As critical constituents of ambient particulate matter, transition metals such as iron may play an important role in health outcomes associated with air pollution. The purpose of this study was to determine the respiratory effects of inhaled ultrafine iron particles in rats. Sprague Dawley rats 10,12 weeks of age were exposed by inhalation to iron particles (57 and 90 ,g/m3, respectively) or filtered air (FA) for 6 h/day for 3 days. The median diameter of particles generated was 72 nm. Exposure to iron particles at a concentration of 90 ,g/m3 resulted in a significant decrease in total antioxidant power along with a significant induction in ferritin expression, GST activity, and IL-1, levels in lungs compared with lungs of the FA control or of animals exposed to iron particles at 57 ,g/m3. NF,B,DNA binding activity was elevated 1.3-fold compared with that of control animals following exposure to 90 ,g/m3 of iron, but this change was not statistically significant. We concluded that inhalation of iron particles leads to oxidative stress associated with a proinflammatory response in a dose-dependent manner. The activation of NF,B may be involved in iron-induced respiratory responses, but further studies are merited. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 227,235, 2003. [source] Timing of exposure to a pulp and paper effluent influences the manifestation of reproductive effects in rainbow troutENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2002Michael R. Van den Heuvel Abstract Rainbow trout were exposed to a secondary treated, thermomechanical/bleached kraft pulp and paper effluent in 12,000-L, flow-through exposure tanks at an environmental research facility located at a pulp and paper mill in Kawerau, New Zealand. Trout (age, 2+ years) were obtained from a local hatchery and exposed either to upstream river water or a nominal concentration of 12% (v/v) effluent diluted in upstream river water. Three treatment groups were used: Effluent exposure that started approximately three months before gonadal growth (eight-month total exposure), effluent exposure that started approximately halfway through gonadal development (two-month total exposure), and trout exposed to reference water alone for the total duration of the experiment. Trout were sacrificed just before spawning; exposure, growth, and reproductive endpoints were assessed during and at the termination of the experiment. Reduction in growth was observed in both sexes in the eight-month treatment group relative to the river water reference treatment group. No differences were observed in condition factor or liver size in either treatment. Females in the eightmonth exposure group also had significantly lower ovary weight. The two-month exposure group showed no differences from the reference group in growth or somatic indices. Estradiol and testosterone were reduced in blood samples taken from the eight-month exposure group by four months into the experiment as compared to the reference treatment. Steroid and vitellogenin levels in individual female trout from this treatment were significantly correlated with gonadosomatic indices (GSI) measured at the termination of the experiment. The GSI was not correlated strongly or consistently with pregnenolone, nor were any treatment-related pregnenolone differences observed, indicating that the steroid hormone reductions likely were not related to cholesterol side-chain cleavage. Male trout showed significant induction of vitellogenin and lower 11-ketotestosterone during the experiment (only the eight-month group was examined), but this did not result in any significant differences in testes development. Thus, this study has shown an impact of pulp mill effluent exposure on the reproductive physiology of female trout that appeared to be hormonally mediated. Furthermore, the effect could only be manifest when the exposure was initiated before the start of gonad development. [source] Induction of neuropeptides in skin innervating sensory neurons by stress and nerve growth factor as a possible reason for hair growth alterationEXPERIMENTAL DERMATOLOGY, Issue 9 2004A. Kuhlmei Recently, we introduced a mouse model launching experimental evidence for stress-induced hair growth inhibition (HGI), pointing to the existence of a brain-hair follicle axis (BFA). We suggested that nerve growth factor (NGF), besides neuropeptide substance P (SP), is a candidate mediator along the BFA. Published data further indicate that stress-related neuropeptides, e.g. calcitonin gene-related peptide (CGRP) and SP may be involved in HGI. SP and CGRP are synthesized in dorsal root ganglia (DRG) and released after axonal transport in the skin. Thus, aim of the present study was to investigate the effect of stress or subcutaneous injection of NGF, which mimics stress and regulates neuropeptide genes in sensory neurons, on the expression of SP and CGRP in DRG. Anagen was induced in C57BL/6 mice by depilation and retrograde tracing was employed on day 9 post-depilation (PD). On day 14 PD, mice were either exposed to sound stress (n = 4) injected subcutaneously with NGF (n = 4) or served as control (n = 4). On day 16 PD, DRG (mean of 30/mouse) were harvested and SP and CGRP in skin-specific sensory neurons, as identified by the tracer dye, were labelled by immunohistochemistry and counted. Stress exposure as well as NGF injection leads to a significant induction of SP and CGRP in retrograde-labelled neurons. This allows us to conclude that sensitive dermal nerve fibres are likely to originate from the presently identified neuropeptide-positive neurons. Peripheral activation of SP-expressing afferent nerve fibres via NGF-dependent pathways may cause neurogenic inflammation, eventually resulting in HGI. [source] Expression of penicillin G acylase from the cloned pac gene of Escherichia coli ATCC11105FEBS JOURNAL, Issue 5 2001Effects of pacR, temperature The structural gene pac in Eschericia coli ATCC11105 encodes penicillin G acylase (PGA). Within the pac gene, there is a regulatory gene pacR, which is transcribed in the opposite direction. Site-directed mutagenesis was performed at base 1045 of pac by replacing a T with a C. This substitution did not alter the amino-acid sequence of PGA, but changed the translation start codon of pacR from AUG to GUG. The expression of the mutant pacR decreased dramatically and the lacZ transcriptional fusion analysis showed that GUG was an extremely poor initiation codon for pacR. The pacR mutation caused PGA expression to be constitutive rather than inductive in two strains (E. coli A56, DH10B). The pac inducer phenylacetic acid (PAA) gave significant induction of PGA production at a concentration of 0.2% in wild type, but PAA at this concentration inhibited both cell growth and PGA production in the pacR mutated strains. The temperature-dependent expression character of pac is preserved in the pacR translation-initiation mutant and the optimum temperature of PGA production was 22 °C in both wild type and mutant. At a higher temperature of 37 °C, the PGA precursor polypeptide could not be matured into subunits and formed inclusion bodies, as revealed by western blot analysis. Our investigations confirmed the hypothesis of pacR-mediated PAA induction for PGA expression and clarified the inhibitory effect of high temperature upon the post-translational processing of the PGA precursor polypeptide. [source] Temporal, spatial and biotic variations in extrafloral nectar secretion by Macaranga tanariusFUNCTIONAL ECOLOGY, Issue 6 2000Heil M. Abstract 1Many plants produce extrafloral nectar (EFN) to nourish ants and other animals which defend them against herbivores. We aimed to find reasons for the high variability in amounts of EFN produced by most plant species. We investigated the influence of several biotic and abiotic factors (time of day, leaf age, nectar removal and leaf damage) on secretion rates of EFN in the common south-east Asian pioneer tree species, Macarangatanarius (L.) Muell. Arg. 2In most experiments leaves were washed with pure water and bagged in nets to protect them against nectar-collecting insects, and nectar was collected and quantified 24 h later. Six soluble sugars and up to eight amino acids were detected in nectar samples derived from untreated, field-grown plants. Total amounts of soluble substances varied more than the relative composition of EFN. 3Nectar secretion rates were highest on young, expanded leaves. A diurnal pattern with a secretion peak in the first 2 h after dusk was detected in the field. Nectar removal had a positive effect and its accumulation a negative effect on further EFN production. Artificial leaf damage (punching leaves with a needle or removing parts of the leaf blade with scissors) led to a significant induction of EFN production for the next 3 days. 4Extrafloral nectar of M. tanarius was secreted in complex patterns influenced by different biotic and abiotic factors; its production appeared to be adapted temporally and spatially in order to ensure optimal use of invested resources. [source] EGFR tyrosine kinase inhibition radiosensitizes and induces apoptosis in malignant glioma and childhood ependymoma xenograftsINTERNATIONAL JOURNAL OF CANCER, Issue 1 2008Birgit Geoerger Abstract Malignant gliomas and childhood ependymomas have a high rate of treatment failure. Epidermal growth factor receptor (EGFR) activation has been implicated in the tumorigenesis and radioresistance of many cancers, including brain tumors. Therefore, combining EGFR targeting with irradiation is a potentially attractive therapeutic option. We evaluated the tyrosine kinase inhibitor gefitinib for its antitumor activity and potential to radio-sensitize in vivo in two xenograft models: an EGFR amplified glioma and an EGFR expressing ependymoma, both derived from primary tumors. When administered at 100 mg/kg for 5 consecutive days, gefitinib-induced partial tumor regression in all treated EGFR amplified IGRG88 glioma xenografts. The addition of 1 Gy of irradiation prior to gefitinib administration resulted in 5 complete and 4 partial regressions for the 9 treated tumors as well as a significant tumor growth delay of 33 days for the combined treatment compared to 19 days for each therapy alone, suggesting additive antitumor activity. Tumor regression was associated with inhibition of AKT and MAPK pathways by gefitinib. In contrast, the ependymoma IGREP83 was sensitive to irradiation, but remained resistant to gefitinib. Combined treatment was associated with inhibition of radiation-induced MAPK phosphorylation and significant induction of apoptotic cell death though radiation-induced AKT phosphorylation was maintained. Depending on the scheduling of both therapies, a trend towards superior antitumor activity was observed with combined treatment. Thus, EGFR targeting through tyrosine kinase inhibition appears to be a promising new approach in the treatment of EGFR-driven glioma, particularly in combination with radiation therapy. © 2008 Wiley-Liss, Inc. [source] Novel inhibitors targeted to methionine aminopeptidase 2 (MetAP2) strongly inhibit the growth of cancers in xenografted nude modelINTERNATIONAL JOURNAL OF CANCER, Issue 1 2005Eunyoung Chun Abstract Inhibition of angiogenesis is emerging as a promising strategy for the treatment of cancer. In our study reported here, the effects of 4 highly potent methionine aminopeptidase 2 (MetAP2) inhibitors, IDR-803, IDR-804, IDR-805 and CKD-732 (designed by structure-based molecular modeling), on angiogenesis and tumor growth were assessed. Concentrations of these inhibitors as low as 2.5 nM were able to inhibit the growth of human umbilical vein endothelial cells (HUVEC) by as much as 50%, arresting growth in the G1 stage of mitosis. An intracellular accumulation of p21WAF1/Cip1 protein was also observed. Furthermore, at higher concentrations (25 nM) of these 4 MetAP2 inhibitors, a significant induction of apoptosis was apparent in the same HUVEC cultures. As a result of these findings, the possible anticancer effects of these inhibitors were examined, utilizing the SNU-398 hepatoma cell line. Interestingly, pretreatment with these inhibitors led to an increased number of apoptotic cells of up to 60% or more, compared to untreated controls. Moreover, utilizing an in vivo xenografted murine model, these inhibitors suppressed the growth of engrafted tumor. In conclusion, these 4 inhibitory compounds potently exert an antiangiogenic effect to inhibit the growth of cancers in vivo and could potentially be useful for the treatment of a variety of cancers. © 2004 Wiley-Liss, Inc. [source] Novel indoloquinoline derivative, IQDMA, inhibits STAT5 signaling associated with apoptosis in K562 cellsJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 6 2008Sheng-Huei Yang Abstract N,-(11H-indolo[3,2-c]quinolin-6-yl)- N,N -dimethylethane-1,2-diamine (IQDMA), an indoloquinoline derivative, synthesized in our laboratory, has been demonstrated to be an effective antitumor agent in human leukemia cells. In the present study, treatment with IQDMA inhibited phosphorylation of epidermal growth factor receptor (EGFR), Src, Bcr-Abl, and Janus-activated kinase (JAK2) in a time-dependent manner. IQDMA also degraded JAK2 protein. Moreover, signal transducer and activator of transcription 5 (STAT5) signaling were also blocked by IQDMA. However, IQDMA did not inhibit other oncogenic and tumor survival pathways such as those mediated by Akt and extracellular signal-regulated kinase 1/2. Furthermore, IQDMA upregulated the expression of p21 and p27 and downregulated the expression of cyclin D1, myeloid cell leukemia-1(Mcl-1), Bcl-XL, and vascular endothelial growth factor (VEGF). Taken together, these results indicate that IQDMA causes significant induction of apoptosis in K562 cells via downregulation of EGFR, Src, Bcr-Abl, JAK2, and STAT5 signaling and modulation of p21, p27, cyclin D1, Mcl-1, Bcl-XL, and VEGF proteins. Thus, IQDMA appears to be a potential therapeutic agent for treating leukemia K562 cells. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:396,404, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20254 [source] Quantification of the expression and inducibility of 12 rat cytochrome P450 isoforms by quantitative RT,PCRJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 6 2006Etienne Caron Abstract The administration of xenobiotics may significantly alter the expression of cytochromes P450 (CYPs), thereby leading to potentially toxic cellular, physiologic, and pharmacologic responses. Indeed, an important task in the development of new therapeutic entities is to evaluate efficiently and quantitatively their potential effects on the expression level of different CYPs. In this report, reverse transcriptase polymerase chain reaction (RT,PCR) was used to measure basal and induced mRNA of a wide range of rat CYP isoforms. Rats (n = 3 per treatment) were treated with five prototype inducers of CYP isoforms or with vehicle only. RT and PCR efficiencies were determined using appropriate RNA and DNA standards. Messenger RNA was quantified by PicoGreen standard curves and normalized to cyclophilin. Quantitative RT,PCR was used successfully to demonstrate that CYP isoforms were induced at the mRNA level following drug administration. Notably, phenobarbital resulted in significant induction of CYP2B1, CYP2B2, CYP2C6, CYP2C13, CYP2E1, CYP3A1, and CYP3A2. 3-Methylcholanthrene induced CYP1A1, CYP1A2, and CYP1B1. CYP2C11 expression was highly variable and suppressed by pyridine, whereas the expression of CYP2E1 was suppressed by dexamethasone. We demonstrated that quantitative RT,PCR can be used to evaluate efficiently the effect of compounds on the expression of a wide range of CYP isoforms. The technique is advantageous over others in that it is very sensitive, efficient and applicable to highly homologous CYP isoforms. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:368,378, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20103 [source] Novel targets for valproic acid: up-regulation of melatonin receptors and neurotrophic factors in C6 glioma cellsJOURNAL OF NEUROCHEMISTRY, Issue 5 2005Lyda M. Rincón Castro Abstract Valproic acid (VPA) is a potent anti-epileptic and effective mood stabilizer. It is known that VPA enhances central GABAergic activity and activates the mitogen-activated protein kinase,extracellular signal-regulated kinase (MAPK,ERK) pathway. It can also inhibit various isoforms of the enzyme, histone deacetylase (HDAC), which is associated with modulation of gene transcription. Recent in vivo studies indicate a neuroprotective role for VPA, which has been found to up-regulate the expression of brain-derived neurotrophic factor (BDNF) in the rat brain. Given the interaction between the pineal hormone, melatonin, and GABAergic systems in the central nervous system, the effects of VPA on the expression of the mammalian melatonin receptor subtypes, MT1 and MT2, were examined in rat C6 glioma cells. The effects of VPA on the expression of glial cell line-derived neurotrophic factor (GDNF) and BDNF were also examined. RT-PCR studies revealed a significant induction of melatonin MT1 receptor mRNA in C6 cells following treatment with 3 or 5 mm VPA for 24 h or 5 mm VPA for 48 h. Western analysis and immunocytochemical detection confirmed that the VPA-induced increase in MT1 mRNA results in up-regulation of MT1 protein expression. Blockade of the MAPK,ERK pathway by PD98059 enhanced the effect of VPA on MT1 expression, suggesting a negative role for this pathway in MT1 receptor regulation. In addition, significant increases in BDNF, GDNF and HDAC mRNA expression were observed after treatment with VPA for 24 or 48 h. Taken together, the present findings suggest that the neuroprotective properties of VPA involve modulation of neurotrophic factors and receptors for melatonin, which is also thought to play a role in neuroprotection. Moreover, the foregoing suggests that combinations of VPA and melatonin could provide novel therapeutic strategies in neurological and psychiatric disorders. [source] The Role of the Vagus Nerve in Mediating the Long-Term Anorectic Effects of LeptinJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2007C. Sachot Leptin, the product of the obese (ob) gene, is mainly known for its regulatory role of energy balance by direct activation of hypothalamic receptors. Recently, its function in the acute control of food intake was additionally attributed to activation of the vagus nerve to regulate meal termination. Whether vagal afferent neurones are involved in longer term effects of leptin on food intake, however, remains undetermined. Using vagotomised (VGX) rats, we sought to clarify the contributions of vagal afferents in mediating the long-lasting effect of leptin on appetite suppression. Intraperitoneal (i.p.) injection of leptin (3.5 mg/kg) attenuated food intake at 4, 6, 8 and 24 h and body weight at 24 h postinjection in SHAM-operated rats; however, this response was not abrogated by vagotomy. In a separate study using immunohistochemistry, we observed leptin-induced Fos expression in the nucleus tractus solitarii, a brain structure where vagal afferent fibres terminate. This signal was not attenuated in VGX animals compared to the SHAM group. Moreover, leptin treatment led to a similar level of nuclear STAT3 translocation, a marker of leptin signalling, in the hypothalami of SHAM and VGX animals. In addition to the effects of leptin, vagotomy surgery itself resulted in a decrease of 24 h food intake. Analyses of brains from saline-treated VGX animals revealed a significant induction of Fos in the nucleus tractus solitarii and changes in agouti-related peptide and pro-opiomelanocortin mRNA expression in the hypothalamus compared to their SHAM counterparts, indicating that the vagotomy surgery itself induced a modification of brain activity in areas involved in regulating appetite. Collectively, our data suggest that vagal afferents do not constitute a major route of mediating the regulatory effect of leptin on food intake over a period of several hours. [source] UV-B INDUCTION OF UV-B PROTECTION IN ULVA PERTUSA (CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 3 2005Young-Seok Han The green macroalga Ulva pertusa Kjellman produced UV-B absorbing compounds with a prominent absorption maximum at 294 nm in response only to UV-B, and the amounts induced were proportional to the UV-B doses. Under a 12:12-h light:dark regime, the production of UV-absorbing compounds occurred only during the exposure periods with little turnover in the dark. There was significant reduction in growth in parallel with the production of UV-B absorbing compounds. The polychromatic action spectrum for the induction of UV-B absorbing compounds in U. pertusa exhibits a major peak at 292 nm with a smaller peak at 311.5 nm. No significant induction was detected above 354.5 nm, and radiation below 285 nm caused significant reduction in the levels of UV-B absorbing compounds. After UV-B irradiation at 1.0 W·m,2 for 9 h, the optimal photosynthetic quantum yield of the samples with UV-B absorbing compounds slightly increased relative to the initial value, whereas that of thalli lacking the compounds declined to 30%,34% of the initial followed by subsequent recovery in dim light of up to 84%,85% of the initial value. There was a positive and significant relationship between the amount of UV-B absorbing compounds with antioxidant activity as determined by the ,,,-diphenyl-,-picrylhydrazyl scavenging assay. In addition to mat-forming characteristics and light-driven photorepair, the existence and antioxidant capacity of UV-B absorbing compounds may confer U. pertusa a greater selective advantage over other macroalgae, thereby enabling them to thrive in the presence of intense UV-B radiation. [source] Melatonin inhibits the expression of the inducible isoform of nitric oxide synthase and nuclear factor kappa B activation in rat skeletal muscleJOURNAL OF PINEAL RESEARCH, Issue 1 2006María Alonso Abstract:, This study investigated whether the induction of inducible nitric oxide synthase (iNOS) produced by acute exercise in rat skeletal muscle could be prevented by melatonin and whether iNOS down-regulation was related to inhibition of nuclear factor kappaB (NF- ,B) activation. Male Wistar rats received melatonin i.p. at a dose of 1.0 mg/kg body weight 30 min before being exercised for 60 min on a treadmill at a speed of 25 m/min and a 10% slope. Exercise caused a significant induction of iNOS protein levels and a marked activation of NF- ,B that were significantly prevented in rats treated with melatonin. Exercise also resulted in increased I,B kinase, (IKK,) and phosphorylated I,B, protein levels, whereas I,B, content decreased. These effects were blocked by melatonin administration. The increase in the muscle concentration of thiobarbituric acid reactive substances and in the oxidized/reduced glutathione ratio induced by exercise was partially prevented by melatonin. Our data indicate that melatonin has potent protective effects against damage caused by acute exercise in rat muscle, preventing oxidative stress, NF- ,B activation and iNOS over-expression. These findings support the view that melatonin treatment, by abolishing the IKK/NF- ,B signal transduction pathway, might block the production of noxious mediators involved in the inflammatory process. [source] Differential apoptosis by gallotannin in human colon cancer cells with distinct p53 statusMOLECULAR CARCINOGENESIS, Issue 3 2007Sahar Al-Ayyoubi Abstract Gallotannin (GT), a plant polyphenol, has shown anticarcinogenic activities in several animal models including colon cancer. In our previous study, we showed that GT inhibits 1,2-dimethylhydrazine-induced colonic aberrant crypt foci and tumors in Balb/c mice, thus supporting a role for GT as a chemopreventive agent in colon cancer. However, at the molecular level, GT's mechanism of chemoprevention is still unclear. In this study, we aim at identifying GT's potential molecular mechanisms of action in in vitro studies. We show that GT differentially inhibits the growth of two isogenic HCT-116 (p53+/+, p53,/,) human colon cancer cells versus normal human intestinal epithelial cells (FHs 74Int). DNA flow cytometric analysis showed that GT induced S-phase arrest in both HCT-116 cell lines. Cell-cycle arrest in p53 (+/+) cells was associated with an increase in p53 protein levels and p21 transcript and protein levels. The inhibition of cell-cycle progression of HCT-116 p53 (+/+) cells by GT correlated with a reduction in the protein levels of cyclin D1, pRb, and the Bax/Bcl-2 ratio. Although GT did not induce apoptosis in p53 (+/+) cells, a significant induction of apoptosis was observed in p53 (,/,) cells as shown by TUNEL staining and flow cytometry analysis. Apoptosis induction in p53 (,/,) cells was associated with a significant increase in Bax/Bcl-2 protein levels. Our results demonstrate that GT inhibits the growth of HCT-116 colon cancer cells in a p53-independent manner but exhibits differential sensitivity to apoptosis induction in HCT-116 cells with distinct p53 status. © 2006 Wiley-Liss, Inc. [source] Assessment of carcinogenic potential of repeated fish fried oil in miceMOLECULAR CARCINOGENESIS, Issue 10 2006Manoj K. Pandey Abstract Our prior studies have shown that single topical treatment of repeated fish fried oil extract (RFFE), containing various polycyclic aromatic hydrocarbons (PAHs), to the dorsal epidermis of mice caused enhancement of DNA damage along with higher expression of p53 and p21WAF1 proteins and cell-cycle arrest. In the present study carcinogenic potential of repeated fish fried oil (RFFO) and RFFE was assessed. Single topical application of RFFO (100 µL/animal) and RFFE (100,500 µg/animal) to Swiss albino female mice resulted in significant induction (1.8- to 7.4-fold) of ornithine decarboxylase activity. Twice weekly topical application of methylcholanthrene (MCA) for 24 wk or single topical application of 7,12-dimethylbenzanthracene (DMBA) or RFFO or RFFE, as initiator followed by twice weekly application of 12-O-tetradecanoyl phorbol myristate acetate (TPA) as promoter for 24 wk, resulted in development of skin papillomas after 6, 7, 18, and 9 wk, respectively. The cumulative number of tumors in MCA, DMBA/TPA, RFFE (200 µg)/TPA, and RFFE (500 µg)/TPA groups were 276, 168, 34, and 58 after 24 wk while negligible or minimal initiating activity was noticed in RFFO/TPA group. No tumors were found in animals either given twice weekly topical application of RFFO or a single initiating dose of DMBA followed by twice weekly application of RFFO. Histopathology of skin of animals treated with RFFE/TPA showed marked proliferation of epidermal layers along with abnormal mitosis and multinucleated tumor appearance. Skin of animals in groups RFFO/TPA and DMBA/RFFO showed sloughing and regeneration of epidermal layers, oedema along with proliferation of fibroblasts. Histochemical localization of ,-glutamyl transpeptidase was found to be substantially higher in skin of mice treated with RFFO/TPA and RFFE/TPA. Animals treated with RFFO/TPA, DMBA/RFFO, and RFFE/TPA resulted in significant induction of cutaneous aryl hydrocarbon hydroxylase (AHH) (421,432%), ethoxyresorufin-O-deethylase (252,316%), and glutathione S-transferase (133,245%) activities. Animals treated with RFFO/TPA, DMBA/RFFO, and RFFE/TPA led to significant reduction in glutathione content (39,44%) with a concomitant increase in lipid peroxidation (254,492%). Animals treated with RFFO/TPA and RFFE/TPA led a significant decrease in catalase (43,69%) and superoxide dismutase (20,31%) activities while glutathione reductase activity was found to be diminished (23,51%) in RFFO, RFFO/TPA, DMBA/RFFO, and RFFE/TPA treated groups. These results suggest that RFFE possess skin tumor initiating activity and that it may have weak promoting activity as well, which may involve free radicals. © 2006 Wiley-Liss, Inc. [source] Syringetin, a flavonoid derivative in grape and wine, induces human osteoblast differentiation through bone morphogenetic protein-2/extracellular signal-regulated kinase 1/2 pathwayMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 11 2009Ya-Ling Hsu Abstract Syringetin (3,5,7,4,-tetrahydroxy-3,,5,dimethoxyflavone), a flavonoid derivative, is present in grape and wine. By means of alkaline phosphatase (ALP) activity, osteocalcin, and type I collagen ELISA, we have shown that syringetin exhibits a significant induction of differentiation in MC3T3-E1 mouse calvaria osteoblasts and human fetal osteoblastic 1.19 cell line human osteoblasts. ALP and osteocalcin are phenotypic markers for early-stage differentiated osteoblasts and terminally differentiated osteoblasts, respectively. Our results indicate that syringetin stimulates osteoblast differentiation at various stages, from maturation to terminally differentiated osteoblasts. Induction of differentiation by syringetin is associated with increased bone morphogenetic protein-2 (BMP-2) production. The BMP-2 antagonist noggin blocked syringetin-mediated ALP activity and osteocalcin secretion enhancement, indicating that BMP-2 production is required in syringetin-mediated osteoblast maturation and differentiation. Induction of differentiation by syringetin is associated with increased activation of SMAD1/5/8 and extracellular signal-regulated kinase 1/2 (ERK1/2). Cotreatment of ERK1/2 inhibitor 2,-amino-3,-methoxyflavone inhibited syringetin-mediated ALP upregulation and osteocalcin production. In conclusion, syringetin increased BMP-2 synthesis, and subsequently activated SMAD1/5/8 and ERK1/2, and this effect may contribute to its action on the induction of osteoblast maturation and differentiation, followed by an increase of bone mass. [source] Signaling pathways in osteoblast proinflammatory responses to infection by Porphyromonas gingivalisMOLECULAR ORAL MICROBIOLOGY, Issue 2 2008T. Ohno Introduction:, We recently investigated global gene expression in ST2 mouse stromal cells infected by the periodontal pathogen Porphyromonas gingivalis using microarray technology, and found that the bacterium induces a wide range of proinflammatory gene expression. Here, we reported the signaling pathways involved in those proinflammatory responses. Methods:, ST2 cells and primary calvarial osteoblasts from C3H/HeN, C57BL/6, and MyD88-deficient (MyD88,/,) mice were infected with P. gingivalis ATCC33277 and its gingipain-deficient mutant KDP136. Expression of the chemokines CCL5 and CXCL10, and matrix metalloproteinase-9 (MMP9) were quantified by real-time polymerase chain reaction, while phosphorylation of protein kinases and degradation of an inhibitor of nuclear factor-,B, I,B-,, were detected by Western blotting, and activation of transcriptional factors was determined by a luciferase reporter assay. The effects of inhibitors of transcriptional factors and protein kinases were also investigated. Results:, Infection by P. gingivalis elicited gene expression of CCL5, CXCL10, and MMP9 in both ST2 cells and osteoblasts. Western blot and reporter assay results revealed activation of nuclear factor-,B (NF-,B) and activator protein-1 transcription factors. The NF-,B inhibitor suppressed the expression of CCL5 and MMP9, but not that of CXCL10, whereas P. gingivalis infection induced significant CCL5 expression in MyD88,/, osteoblasts. In addition, activation of protease-activated receptors by trypsin elicited significant induction of CXCL10. Conclusion:, Our results suggest that various proinflammatory responses in P. gingivalis -infected stromal/osteoblast cells are NF-,B-dependent, but not always dependent on the Toll-like receptor/MyD88 pathway, while some responses are related to the activation of protease-activated receptors. Thus, P. gingivalis does not fully utilize well-established pathogen recognition molecules such as Toll-like receptors. [source] Comparison of inflammatory changes caused by Porphyromonas gingivalis with distinct fimA genotypes in a mouse abscess modelMOLECULAR ORAL MICROBIOLOGY, Issue 3 2004K. Nakano The fimA gene of Porphyromonas gingivalis, encoding fimbrillin (a subunit protein of fimbriae) has been classified into six genotypes (types I,V and Ib). The genotypic variation was previously suggested to be related to the severity of adult periodontitis in the general population. In this study, we compared inflammatory changes caused by bacterial infection to study pathogenic heterogeneity among the different fimA strains in a mouse abscess model. Bacterial suspensions of 13 P. gingivalis strains representing the six fimA types were subcutaneously injected into female BALB/c mice, and serum sialic acid concentrations were assayed as a quantitative host inflammatory parameter. Type II fimA organisms caused the most significant induction of serum sialic acid, as well as other infectious symptoms, followed by types Ib, IV and V. In contrast, types I and III caused weak inflammatory changes. In addition, fimA mutants of type II strains clearly lost their infectious ability. These findings suggest that fimA genotypic variation affects expression of P. gingivalis virulence. [source] Differential in vitro CD4+/CD8+ T-cell response to live vs. killed Leishmania majorPARASITE IMMUNOLOGY, Issue 2 2010M. NATEGHI ROSTAMI Summary Clinical trials of killed Leishmania vaccines showed a limited efficacy compared with leishmanization (LZ). The reason for this difference in protection against cutaneous leishmaniasis (CL) is not known and in vivo studies on T-cell function may provide valuable information. Nevertheless, there are limited studies on the nature of the stimulatory effects of live vs. killed parasites on human T cells in vitro. A total of nine Leishmanin Skin Test+ volunteers with a history of self-healing CL (HCL) and seven healthy volunteers were included in this study. 5,6-carboxyfluroescein diacetate succinimidyl ester-labelled CD4+/CD8+ lymphocytes were cultured with killed Leishmania Lysate (Killed LL) or live Leishmania major (Live LM) and analysed for proliferation using flow cytometry. Culture supernatants were used for cytokine titration. In HCL volunteers, upon stimulation with killed LL, the number of proliferated CD4+/CD8+ cells was significantly more than that of unstimulated (P < 0·001) or live LM stimulated (P < 0·05) cells, or cells from controls (CD4+/CD8+: P < 0·05/P < 0·001). Stimulation of CD4+ cells with Live LM (P < 0·001) or Killed LL (P < 0·05) induced a significantly higher IFN-, production compared with that of controls, but Live LM induced significantly (P < 0·05) more IFN-, than Killed LL. A significantly (P < 0·05) higher IFN-, production was observed when CD8+ cells were stimulated with Live LM. Cells from HCL volunteers showed significantly more IL-10 production to Live LM stimulation compared with that of controls (CD4+: P < 0·05 /CD8+: P < 0·001) or cells stimulated with Killed LL (CD4+/CD8+: P < 0·001/P < 0·0005). Whereas Killed LL induced more proliferation response in purified T cells, Live LM induced cytokine production without significant induction of proliferation. The results from healed CL volunteers in this study could be implicated in further studies on T-cell response in vaccinated individuals. [source] Response of vulval lichen sclerosus and squamous hyperplasia to photodynamic treatment using sustained topical delivery of aminolevulinic acid from a novel bioadhesive patch systemPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 2 2009Agnieszka A. Zawislak This study evaluated the clinical and histopathological responses of vulval lichen sclerosus (LS) and squamous hyperplasia (SH) to photodynamic therapy (PDT). A novel bioadhesive patch containing aminolevulinic acid (ALA) at a dose of (38 mg/cm2) was used to treat 10 patients before irradiation with light of 630 nm. Clinical, histopathological and pathological responses to treatment were assessed at 6 weeks post-treatment. After 17 cycles of PDT, six patients reported significant symptomatic relief and no cutaneous photosensitivity. Histopathological differences were not demonstrated, but statistically significant induction of apoptosis was seen. It can be concluded that ALA-PDT patch-based formulation is pragmatic and primarily offers symptomatic management of vulval LS and SH. [source] Aluminum alters cell viability and axonal transport system in Alzheimer's disease pathogenic mutation-bearing cellsPSYCHOGERIATRICS, Issue 2 2004Hisashi TANII Abstract Background:, We previously reported that pulse exposure of cultured rat neurons to aluminum-maltol resulted in an abnormal distribution of both neurofilament-L (NF-L) and fast axonal transported proteins. It was also found that the presenilin 1 (PS1) missense mutation and aluminum affected early neuronal development of the mouse brain. It has been reported that the presenilin (PS) mutation alters neurite outgrowth, and the axonal transport of the amyloid precursor protein (APP)/PS complex is mediated by kinesin. The present study hypothesizes that aluminum might modulate axonal transport and neurite outgrowth in APP/PS mutant-bearing cells. Methods:, We treated SH-SY5Y cells and HEK293 cells bearing FAD mutations with aluminum-maltol (Al-mal) (0, 250 µm, 500 µm, 1 mm, 2 mm) for 1 h, followed by propidium iodide (PI) and Calcein-AM staining, live and dead assay, double staining of NF-L/synaptophysin or APP/JNK interacting protein-1 (JIP-1) 3 days after treatment. Results:, Apoptosis was induced Al-mal treatment in a dose-dependent manner in all cell lines. In SH-SY5Y cells bearing PS1 mutations, there were no differences in the rate of cell viability, except for morphological changes observed by Calcein-AM staining. The distribution of NF-L and synaptophysin was modified by PS1 mutations and aluminum, suggesting that the PS mutation induces neuronal dysfunction by disturbance of the axonal transport system. The APP mutation-bearing cell lines showed significant induction of apoptosis compared to that of wild-type cells. Oxidative stress might thus influence cell viability in APP mutation-bearing cells. Enhancement of JIP-1 staining may reflect a disturbance of the intracellular axonal transport system, as well as compensation due to apoptotic changes. Conclusion:, The present results, when taken together, show that aluminum alters cell viability and the axonal transport system in FAD pathogenic mutation-bearing cells. [source] Systemic plant signal triggers genome instabilityTHE PLANT JOURNAL, Issue 1 2004Jody Filkowski Summary Previously, we have shown that infection of tobacco plants with a viral pathogen triggers local and systemic induction of homologous recombination (HR). Here, we have tested the hypothesis of whether free radicals are potentially involved in the induction of the systemic effect. We report a significant induction of HR in tobacco plants treated with radical-generating agents, UVC or rose Bengal (RB). Importantly, the recombination increase was observed in local (treated) as well as systemic (non-treated) tissue. The systemic increase in recombination implies the existence of a signal that is transmitted to non-treated tissue. Several sets of grafting experiments proved the generation of said signal by both RB and UVC exposure. A statistically significant increase in HR was observed in tissue that received a systemic signal via a grafted leaf. Similar data were obtained from transgenic plants naphthalene degrading salicylate 1-hydroxylase (NahG) unable to accumulate salicylic acid (SA). Interestingly, pre-treatment of plants with the radical-scavenging compound N -acetyl- l -cysteine (NAC) led to a significantly lower recombination increase upon grafting after treatment with UVC and RB. Moreover, leaves taken for grafting from NAC-pre-treated plants exhibited a lower level of oxidized organic compounds. Our data suggest the involvement of free radical production in either generation or maintenance of the recombination signal. We discuss potential mechanisms for generation of the signal and possible adaptive advantages of enhanced genomic flexibility following exposure to DNA-damaging agents. [source] Reduction of human prostate tumor vascularity by the ,1-adrenoceptor antagonist terazosinTHE PROSTATE, Issue 2 2001Kaspar Keledjian Abstract BACKGROUND We previously demonstrated that the quinazoline-derived a1-adrenoceptor antagonists doxazosin and terazosin suppress prostate cancer growth via apoptosis induction. The aim of this study was to determine the potential effect of a1-adrenoceptor antagonists on tumor vascularity of the human prostate. METHODS A total of 34 men with benign prostatic hyperplasia (BPH) who have been on terazosin treatment (for the obstructive symptoms) were pathologically diagnosed with prostate cancer following surgery. These patients were stratified according to the length of treatment periods with terazosin into two groups, 1 week,6 months, and 6,17 months. The control group consisted of prostatectomy specimens from 25 untreated prostate cancer patients undergoing surgery for localized disease. Formalin-fixed, paraffin-embedded prostate specimens were analyzed for apoptosis (TUNEL assay), cell proliferation (Ki-67), microvessel density (MVD) (von Willebrand factor/Factor VIII), vascular endothelial growth factor (VEGF) expression, and prostate specific antigen (PSA) immunoreactivity. RESULTS A significant induction of apoptosis was observed among cancerous prostatic epithelial cells in the terazosin-treated, as compared to the untreated prostate cancer specimens, while there was no significant change in the proliferative index of the same tumor cell populations after treatment. Furthermore, terazosin resulted in a significant decrease in prostate tissue MVD compared with the untreated group (P,<,0.01), that correlated with the increased apoptotic index of the cancerous areas. Tissue PSA expression in the prostatic tumor foci was also markedly reduced after terazosin treatment, while no significant changes in VEGF expression were detected. CONCLUSIONS These findings provide the first evidence that terazosin, a quinazoline-based a1-blocker decreases prostate tumor vascularity. Our study has significant clinical implications in identifying selected ,1-adrenoceptor antagonists as potential anti-tumor agents with apoptotic and anti-angiogenic effects in the human prostate that can be exploited for the treatment of advanced prostate cancer. Prostate 48:71,78, 2001. © 2001 Wiley-Liss, Inc. [source] Successful granulocyte-colony stimulating factor treatment of Crohn's disease is associated with the appearance of circulating interleukin-10-producing T cells and increased lamina propria plasmacytoid dendritic cellsCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2009P. J. Mannon Summary Granulocyte-colony stimulating factor (G-CSF) has proved to be a successful therapy for some patients with Crohn's disease. Given the known ability of G-CSF to exert anti-T helper 1 effects and to induce interleukin (IL)-10-secreting regulatory T cells, we studied whether clinical benefit from G-CSF therapy in active Crohn's disease was associated with decreased inflammatory cytokine production and/or increased regulatory responses. Crohn's patients were treated with G-CSF (5 µg/kg/day subcutaneously) for 4 weeks and changes in cell phenotype, cytokine production and dendritic cell subsets were measured in the peripheral blood and colonic mucosal biopsies using flow cytometry, enzyme-linked immunosorbent assay and immunocytochemistry. Crohn's patients who achieved a clinical response or remission based on the decrease in the Crohn's disease activity index differed from non-responding patients in several important ways: at the end of treatment, responding patients had significantly more CD4+ memory T cells producing IL-10 in the peripheral blood; they also had a greatly enhanced CD123+ plasmacytoid dendritic cell infiltration of the lamina propria. Interferon-, production capacity was not changed significantly except in non-responders, where it increased. These data show that clinical benefit from G-CSF treatment in Crohn's disease is accompanied by significant induction of IL-10 secreting T cells as well as increases in plasmacytoid dendritic cells in the lamina propria of the inflamed gut mucosa. [source] Expression and function of the purinergic receptor P2X7 in patients with pulmonary tuberculosisCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2006S. Franco-Martínez Summary P2X7 is a channel receptor gated by adenosine triphosphate (ATP) that is involved in the killing of intracellular mycobacteria. To explore further the role of P2X7 in immunity against Mycobacterium tuberculosis, we studied its expression and function in 19 patients with pulmonary tuberculosis (TB) and 19 healthy contacts. Flow cytometry analysis showed a similar and variable expression of P2X7 in TB patients and healthy subjects. In contrast, P2X7 mARN levels were significantly higher in TB patients. When the function of the P2X7 receptor in peripheral blood mononuclear cells (PBMC) was assessed by the effect of exogenous ATP on apoptosis, the uptake of the fluorescent marker Lucifer yellow or extracellular signal regulated kinase (ERK) phosphorylation, no significant differences were detected in patients and controls. However, mRNA macroarray analysis showed that upon stimulation with ATP, the PBMC from TB patients showed a significant induction of a higher number of cytokine genes (27 of 96), and a lower number of apoptosis genes (20 of 96) compared to healthy controls (17 and 76 genes, respectively). These results suggest that although the PBMC from TB patients do not show apparent abnormalities in the expression of P2X7, and the intracellular signals generated through it, the pattern of gene expression induced by ATP in these cells is different from that found in healthy contacts. This phenomenon suggests a defective function of P2X7 in the immune cells from TB patients, a condition that may contribute to the inability of these patients to eliminate the mycobacteria. [source] BMP-2 and FGF-2 Synergistically Facilitate Adoption of a Cardiac Phenotype in Somatic Bone Marrow c-kit+/Sca-1+ Stem CellsCLINICAL AND TRANSLATIONAL SCIENCE, Issue 2 2008Brent R. DeGeorge, Jr. B.S. Abstract The aim of this study was to explore the effect of bone morphogenetic protein-2 (BMP-2) and fibroblast growth factor-2 (FGF-2), paracrine factors implicated in both cardiac embryogenesis and cardiac repair following myocardial infarction (MI),on murine bone marrow stem cell (mBMSC) differentiation in an ex vivo cardiac microenvironment. For this purpose, green fluorescent protein (GFP) expressing hematopoietic lineage negative (lin-) c-kit ligand (c-kit) and stem cell antigen-1 (Sca-1) positive (GFP-lin-/c-kit+/sca+) mBMSC were co-cultured with neonatal rat ventricular cardiomyocytes (NVCMs). GFP+ mBMSC significantly induced the expression of BMP-2 and FGF-2 in NVCMs, and approximately 4% GFP+ mBMSCs could be recovered from the co-culture at day 10. The addition of BMP-2 in concert with FGF-2 significantly enhanced the amount of integrated GFP+ mBMSCs by 5-fold (,20%), whereas the addition of anti-BMP-2 and/or anti-FGF-2 antibodies completely abolished this effect. An analysis of calcium cycling revealed robust calcium transients in GFP+ mBMSCs treated with BMP-2/FGF-2 compared to untreated co-cultures. BMP-2 and FGF-2 addition led to a significant induction of early (NK2 transcription factor related, locus 5; Nkx2.5, GATA binding protein 4; GATA-4) and late (myosin light chain kinase [MLC-2v], connexin 43 [Cx43]) cardiac marker mRNA expression in mBMSCs following co-culture. In addition, re-cultured fluorescence-activated cell sorting (FACS)-purified BMP-2/FGF-2-treated mBMSCs revealed robust calcium transients in response to electrical field stimulation which were inhibited by the L-type calcium channel (LTCC) inhibitor, nifedipine, and displayed caffeine-sensitive intracellular calcium stores. In summary, our results show that mBMSCs can adopt a functional cardiac phenotype through treatment with factors essential to embryonic cardiogenesis that are induced after cardiac ischemia. This study provides the first evidence that mBMSCs with long-term self-renewal potential possess the capability to serve as a functional cardiomyocyte precursor through the appropriate paracrine input and cross-talk within an appropriate cardiac microenvironment. [source] | |||||||||||||||||||||||||||||||