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Adenosine Deaminase (adenosine + deaminase)

Distribution by Scientific Domains
Medical Sciences59%
Chemistry27%
Life Sciences13%

Terms modified by Adenosine Deaminase

  • adenosine deaminase activity
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    Selected Abstracts

    Activity of Adenosine Deaminase (ADA) and Adenylate Deaminase (AMPDA) Towards 6-Chloropurine Nucleosides Modified in the Ribose Moiety

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2004
    Pierangela Ciuffreda
    Abstract The enzymes adenosine deaminase (ADA) and adenylate deaminase (AMPDA) are able to catalyze the hydrolytic dechlorination of 6-chloropurine riboside and the corresponding 2,,3,- O -isopropylidene derivative, but show no activity towards the 3,4- O -isopropylidene-1-methylriboside of 6-chloropurine and adenine. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

    Adenylate Deaminase (5,-Adenylic Acid Deaminase, AMPDA)-Catalyzed Deamination of 5,-Deoxy-5,-Substituted and 5,-Protected Adenosines: A Comparison with the Catalytic Activity of Adenosine Deaminase (ADA)

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2003
    Pierangela Ciuffreda
    Abstract The enzyme adenylate deaminase (AMPDA) is able to catalyze the hydrolytic deamination of 5,-substituted and 5,-protected 5,-deoxyadenosines, whereas limited or no activity is shown by adenosine deaminase (ADA) towards the same substrates. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Effects of electromagnetic radiation from a cellular telephone on the oxidant and antioxidant levels in rabbits

    CELL BIOCHEMISTRY AND FUNCTION, Issue 4 2002
    M. Kemal Irmak
    Abstract The number of reports on the effects induced by electromagnetic radiation (EMR) in various cellular systems is still increasing. Until now no satisfactory mechanism has been proposed to explain the biological effects of this radiation. Oxygen free radicals may play a role in mechanisms of adverse effects of EMR. This study was undertaken to investigate the influence of electromagnetic radiation of a digital GSM mobile telephone (900,MHz) on oxidant and antioxidant levels in rabbits. Adenosine deaminase, xanthine oxidase, catalase, myeloperoxidase, superoxide dismutase (SOD) and glutathione peroxidase activities as well as nitric oxide (NO) and malondialdehyde levels were measured in sera and brains of EMR-exposed and sham-exposed rabbits. Serum SOD activity increased, and serum NO levels decreased in EMR-exposed animals compared to the sham group. Other parameters were not changed in either group. This finding may indicate the possible role of increased oxidative stress in the pathophysiology of adverse effect of EMR. Decreased NO levels may also suggest a probable role of NO in the adverse effect. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Age-dependent variations of cell response to oxidative stress: Proteomic approach to protein expression and phosphorylation

    ELECTROPHORESIS, Issue 14 2005
    Yuri Miura Dr.
    Abstract We investigated the protein profiles of variously aged rat astrocytes in response to oxidative stress. After H2O2 -exposure of cells at 100,µM for 30,min, the relative intensity of ten protein spots changed on two-dimensional (2-D) gels compared with control gels after silver staining. Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis after in-gel digestion revealed that six of these spots corresponded to three kinds of proteins, each of which was composed of a protein and its modified form with a different isoelectric point (pI). These three proteins were identified as peroxiredoxins (PRDXs) II and III, and calpactin I light chain (p11). H2O2 -exposure increased the intensity of the spot with lower pI and simultaneously decreased that of the spot with higher pI for both PRDXs II and III. In addition, the expression of annexin VII, S -adenosyl- L -homocysteine hydrolase, elongation factor II fragment (EF-II), and adenosine deaminase was increased by H2O2 -exposure in astrocytes from variously aged rats. Using the Pro-Q® Diamond staining, heat shock protein 60,kDa (Hsp 60) and ,-tubulin were observed to be phosphorylated upon H2O2 -exposure. While phosphorylation of ,-tubulin was correlated positively with age, the changes in abundance of ten protein spots as described above were independent of age. These results suggest that aging does not suppress the responses aimed at limiting injury and promoting repair brought about by severe oxidative stress, and might affect cell dynamics including the formation of microtubules. [source]

    Immunoregulatory effects of adenosine 5,-triphosphate on cytokine release from stimulated whole blood

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2005
    Els L. R. Swennen
    Abstract In vitro studies suggest that extracellular nucleotides and nucleosides may be important regulators of inflammatory and immune responses. Most studies with adenosine 5,-triphosphate (ATP) have been performed in cell lines, which are remote from the human situation. The purpose of the present study was to determine the effects of ATP on TNF-,, IL-6 and IL-10 release in stimulated whole blood. Blood samples were drawn from healthy volunteers and incubated with ATP and lipopolysaccharide (LPS) + phytohemagglutinin (PHA) for 24,h. Contrary to expectations, ATP at 100,,M and 300,,M induced a reduction in TNF-, secretion by 32±8% (mean ± SEM) and 65±4%, respectively. Furthermore, these ATP concentrations induced an increase in IL-10 secretion by 48±5% and 62±7% in whole blood. The ATP analogue adenosine 5,-O-(3-thiotriphosphate) (ATP-,-S) and adenosine 5,-diphosphate (ADP) also inhibited TNF-, release, but only ADP showed a stimulatory effect on IL-10. Co-treatment with adenosine deaminase did not reverse the ATP effect on TNF-, and IL-10. These results show, for the first time, that ATP inhibits the inflammatory response in stimulated whole blood as indicated by inhibition of TNF-, and stimulation of IL-10 release and that this effect is predominantly mediated by ATP and not by adenosine. [source]

    Adenylate Deaminase (5,-Adenylic Acid Deaminase, AMPDA)-Catalyzed Deamination of 5,-Deoxy-5,-Substituted and 5,-Protected Adenosines: A Comparison with the Catalytic Activity of Adenosine Deaminase (ADA)

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2003
    Pierangela Ciuffreda
    Abstract The enzyme adenylate deaminase (AMPDA) is able to catalyze the hydrolytic deamination of 5,-substituted and 5,-protected 5,-deoxyadenosines, whereas limited or no activity is shown by adenosine deaminase (ADA) towards the same substrates. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Induction of 150-kDa adenosine deaminase that acts on RNA (ADAR)-1 gene expression in normal T lymphocytes by anti-CD3-, and anti-CD28

    IMMUNOLOGY, Issue 4 2007
    Dama Laxminarayana
    Summary We and other investigators have demonstrated up-regulation of the expression of the RNA-editing gene 150-kDa adenosine deaminase that acts on RNA (ADAR1) in systemic lupus erythematosus (SLE) T cells and B cells, peripheral blood mononuclear cells (PBMC), natural killer (NK) cells. The presence of a small proportion of activated T cells is the hallmark of SLE. Therefore, it was hypothesized that 150-kDa ADAR1 gene expression is induced by the physiological activation of T cells. To examine this hypothesis, normal T cells were activated by anti-CD3-, plus anti-CD28 for various time periods from 0 to 48 hr. The expression of 110-kDa and 150-kDa ADAR1, and interleukin (IL)-2 and ,-actin gene transcripts was analysed. An approximately fourfold increase in 150-kDa ADAR1 gene expression was observed in activated T cells. ADAR2 gene transcripts are substrates for ADAR1 and ADAR2 enzymes. Therefore, we assessed the role of the 150-kDa ADAR enzyme in editing of ADAR2 gene transcripts. In activated T cells, site-selective editing of the ,2 site was observed. Previous studies indicate that this site is predominantly edited by ADAR1. In addition to this, novel editing sites at base positions ,56, ,48, ,45, ,28, ,19, ,15, +46 and +69 were identified in activated T cells. On the basis of these results, it is proposed that 150-kDa ADAR1 gene expression is selectively induced in T cells by anti-CD3-, and anti-CD28 stimulation and that it may play a role in site-selective editing of gene transcripts and in altering the functions of several gene products of T cells during activation and proliferation. [source]

    Therapeutic benefit of pentostatin in severe IL-10,/, Colitis

    INFLAMMATORY BOWEL DISEASES, Issue 7 2008
    Jeffrey B. Brown MD
    Abstract Background: Pentostatin, an adenosine deaminase (ADA) inhibitor, is a purine antimetabolite used for the treatment of leukemias. ADA inhibition blunts expansion of proliferating lymphocytes and increases adenosine release, a potent anti-inflammatory molecule. Human inflammatory bowel disease (IBD) is driven by expansion of effector T cells (Teff) that overwhelm reulatory T cells (Treg) and propagate innate immune reponses. Here we study the therapeutic benefits of ADA inhibition to impair Teff cell expansion and reduce inflammatory cytokine release in IL-10-deficient (IL-10 -/- ) mice. Methods: Colitis was induced in IL-10 -/- mice by administering piroxicam for two weeks. Mice were treated with daily pentostatin or phosphate-buffered saline for 1 week and effects on tissue inflammation, lymphocyte numbers and cytokine production examined. Results: Pentostatin reduced inflammation by >50% and nearly normalized serum amyloid A levels. Lymphocyte expansions in the colon and mesenteric lymph node (MLN) (3.5-fold and >5-fold respectively) dropped by >50-90%. Pro-inflammatory factors in the colon and MLN (IL-1,, IFN-,, IL-6, CXCL10, TNF) dropped whereas FoxP3 and TGF-, were unchanged. Reductions in cytokine production from equivalent numbers of T cells from pentostatin-treated mice after in vitro (36h) or in vivo (3h) activation suggested anti-inflammatory effects of pentostatin independent of lymphodepletion contributed to its therapeutic benefit. Analysis of mucosal lymphocyte subsets suggested pentostatin reduced numbers of effector CD4+ CD69+ T cells, while sparing CD4+ CD62L+ T cells. Conclusions: Pentostatin dosages that avoid severe lymphocyte depletion effectively treat colitis by impairing Teff cell expansion and reducing pro-inflammatory cytokine production while preserving regulatory Treg populations and function. (Inflamm Bowel Dis 2008) [source]

    Diagnostic value of leptin in tuberculous pleural effusions

    INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 11 2006
    G. CELIK
    Summary It is suggested that leptin may be involved in inflammation. Although relation between leptin levels and active pulmonary tuberculosis has been studied, there is no information about relation between leptin levels and tuberculous pleural effusions (TPE). We evaluated the diagnostic value of pleural fluid and serum leptin levels in TPE and compared them with adenosine deaminase (ADA). Forty-five patients, 17 tuberculous effusion and 28 nontuberculous effusion, with exudative pleural effusions were included. Leptin and ADA levels were measured from serum and pleural fluid in all patients. There were no statistically significant differences between tuberculous and nontuberculous groups with respect to the serum ADA activity and pleural fluid/serum leptin ratio. On the contrary, pleural fluid leptin level, pleural fluid ADA activity, serum leptin level and pleural fluid/serum ADA activity ratio were statistically different between tuberculous and nontuberculous groups. When leptin levels were corrected for body mass index, serum leptin levels did not reach statistical significance. Cut-off points to predict tuberculosis were calculated as 9.85 ng/ml and 35.55 U/l for pleural fluid leptin level and pleural fluid ADA activity, respectively. Sensitivity, specificity and area under the curve ± standard error were 82.4%, 82.1%, 0.83 ± 0.07 for pleural fluid leptin levels and 100%, 100%, 1.00 ± 0.00 for pleural fluid ADA activity, respectively; the difference between these curves was significant (p = 0.01). Pleural fluid leptin levels were lower in tuberculous effusions than in other exudates. Pleural fluid leptin has a diagnostic value for TPE but not as good as that of ADA. [source]

    Deamination of adenosine by extracts of Penicillium politans NRC-510

    JOURNAL OF BASIC MICROBIOLOGY, Issue 2 2005
    Ali M. Elshafei Prof.
    Cell-free extracts of nitrate-grown Penicillium politans NRC-510 could catalyze the hydrolytic deamination of adenosine to inosine maximally at pH 6.0 and 45 °C. However the same extracts could not catalyze the N-glycosidic bond cleavage of adenosine at pH 4.0, 6.0 and 8.0. Incubation of the extracts at 55 °C for 30 minutes caused about 31% loss in activity whereas incubation of the extracts at 60 °C for 15 minutes caused a complete loss of enzyme activity. Results indicated the absence of the involvement of sulfhydryl groups in the catalytic site of adenosine deaminase. The enzyme is inhibited by ethylene diamine tetraacetate indicating that adenosine deaminase is a metalloenzyme. MnCl2 and MgCl2 had a remarkable activating effect, whereas HgCl2, CaCl2 and ZnSO4 showed an inhibitory effect on enzyme activity. Dialyzing the extracts for 24 hours significantly increase deaminase activity by about 33%. The apparent Km value was calculated for adenosine and found to be 3.63 × 10,3M, which indicates high affinity of adenosine deaminase for its substrate adenosine. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Pleural fluid interferon-, and adenosine deaminase levels in tuberculosis pleural effusion: a cost-effectiveness analysis

    JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 2 2005
    S.K. Sharma
    Abstract Pleural fluid levels of interferon-, (IFN-,) and adenosine deaminase (ADA) have been found to be high in patients with tuberculosis (TB). The present study was carried out to compare the diagnostic utility of these two markers and to carry out a cost-effectiveness analysis of performing IFN-, estimation in comparison to ADA. A total of 52 patients with pleural effusion, 35 of which were found to have TB etiology, were prospectively included for estimation of ADA and IFN-, levels. The difference in the cost of performing the two diagnostic tests was compared with the cost of the treatment for a patient with TB. Pleural fluid IFN-, (median [range]: 2,100 [70,14,000] vs. 3 [0,160]; P<0.001) as well as ADA levels (mean [SD]: 93.1 [62.3] vs 15.4 [8.7]; P<0.001) were significantly higher in patients with TB effusion. Even though IFN-, estimation was more sensitive (97.1 vs. 91.4%), the extra cost of IFN-, estimation for detecting one patient with TB was found to be equivalent to the cost of a complete course of antituberculosis treatment for six patients. In developing countries, where TB is rampant and cost is a major concern, pleural fluid IFN-, estimation does not seem to be a cost-effective investigation method for differentiating TB from non-TB pleural effusion. J. Clin. Lab. Anal. 19:40,46, 2005. © 2005 Wiley-Liss, Inc. [source]

    A theoretical study on the catalytic mechanism of Mus musculus adenosine deaminase

    JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 12 2010
    Xian-Hui Wu
    Abstract The catalytic mechanism of Mus musculus adenosine deaminase (ADA) has been studied by quantum mechanics and two-layered ONIOM calculations. Our calculations show that the previously proposed mechanism, involving His238 as the general base to activate the Zn-bound water, has a high activation barrier of about 28 kcal/mol at the proposed rate-determining nucleophilic addition step, and the corresponding calculated kinetic isotope effects are significantly different from the recent experimental observations. We propose a revised mechanism based on calculations, in which Glu217 serves as the general base to abstract the proton of the Zn-bound water, and the protonated Glu217 then activates the substrate for the subsequent nucleophilic addition. The rate-determining step is the proton transfer from Zn-OH to 6-NH2 of the tetrahedral intermediate, in which His238 serves as a proton shuttle for the proton transfer. The calculated kinetic isotope effects agree well with the experimental data, and calculated activation energy is also consistent with the experimental reaction rate. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 [source]

    The large form of ADAR 1 is responsible for enhanced hepatitis delta virus RNA editing in interferon- , -stimulated host cells

    JOURNAL OF VIRAL HEPATITIS, Issue 3 2006
    D. Hartwig
    Summary., Hepatitis delta virus (HDV) RNA editing controls the formation of hepatitis-delta-antigen-S and -L and therefore indirectly regulates HDV replication. Editing is thought to be catalysed by the adenosine deaminase acting on RNA1 (ADAR1) of which two different forms exist, interferon (IFN)- , -inducible ADAR1-L and constitutively expressed ADAR1-S. ADAR1-L is hypothesized to be a part of the innate cellular immune system, responsible for deaminating adenosines in viral dsRNAs. We examined the influence of both forms on HDV RNA editing in IFN- , -stimulated and unstimulated hepatoma cells. For gene silencing, an antisense oligodeoxyribonucleotide against a common sequence of both forms of ADAR1 and another one specific for ADAR1-L alone were used. IFN- , treatment of host cells led to approximately twofold increase of RNA editing compared with unstimulated controls. If ADAR1-L expression was inhibited, this substantial increase in editing could no longer be observed. In unstimulated cells, ADAR1-L suppression had only minor effects on editing. Inhibition of both forms of ADAR1 simultaneously led to a substantial decrease of edited RNA independently of IFN- , -stimulation. In conclusion, the two forms of ADAR1 are responsible almost alone for HDV editing. In unstimulated cells, ADAR1-S is the main editing activity. The increase of edited RNA under IFN- , -stimulation is because of induction of ADAR1-L, showing for the first time that this IFN-inducible protein is involved in the base modification of replicating HDV RNA. Thus, induction of ADAR1-L may at least partially cause the antiviral effect of IFN- , in natural immune response to HDV as well as in case of therapeutic administration of IFN. [source]

    Six novel mutations of the ADAR1 gene in patients with dyschromatosis symmetrica hereditaria: Histological observation and comparison of genotypes and clinical phenotypes

    THE JOURNAL OF DERMATOLOGY, Issue 7 2008
    Taisuke KONDO
    ABSTRACT Dyschromatosis symmetrica hereditaria (DSH), is a pigmentary genodermatosis of autosomal dominant inheritance. Since we clarified that the disease is caused by a mutation of the adenosine deaminase acting on the RNA 1 gene (ADAR1) in 2003, the molecular pathogenesis of a peculiar clinical feature of the disease has been expected to be clarified. We examined five familial cases and one sporadic case of Japanese families with DSH. The mutation analyses were done with single-strand conformation polymorphism/heteroduplex (SSCP/HD) analysis and direct sequencing of ADAR1. The DNA analysis of each patient revealed one missense mutation (p.F1091S), two nonsense mutations (p.C893X, p.S581X) and three frame-shift mutations (p.E498fsX517, p.F1091fsX1092, p.L855fsX856). Visual and electron microscopic findings showed abundant melanin pigment deposited all over the basal layer, and enlarged melanocytes with long dendrites located in the pigmented lesions with small or immature melanosomes scattered sparsely in the cytoplasm, but in the adjacent keratinocytes many small melanosomes were singly dispersed or aggregated. The hypopigmented areas showed little melanin deposition and reduced numbers of melanocytes in which much degenerative cytoplasmic vacuole formation could be observed by electron microscopy. Herein, we report six cases of DSH with six novel mutations. The variety of their clinical phenotypes even in the pedigree may suggest the presence of factors other than the ADAR1 gene influencing the extent of the clinical skin lesion. Microscopic findings suggest that the clinical appearance must have developed directly by melanocyte variations mainly induced by the ADAR1 gene mutations. [source]

    ORIGINAL ARTICLE: Endogenous Adenosine Down-Modulates Mid-Trimester IntraAmniotic Tumor Necrosis Factor-, Production

    AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2009
    Uma Perni
    Problem, To determine whether adenosine in amniotic fluid down-regulates pro-inflammatory cytokine production. Method of study, Mid-trimester amniotic fluid from 21 women was incubated ex vivo in the presence or absence of human adenosine deaminase, the enzyme that irreversibly degrades adenosine. After 24 hr, supernatants were assayed by ELISA for tumor necrosis factor-, (TNF-,), interleukin (IL)-6, and IL-10. Clinical parameters were obtained after completion of laboratory testing. Results, Inclusion of adenosine deaminase resulted in a median increase in TNF-, production from 0.9 to 7.3 pg/mL (P = 0.0014). IL-6 production exhibited a non-significant median increase from <2.0 to 53.0 pg/mL (P = 0.0780). Median IL-10 production increased slightly from a median of <0.2 to 1.3 pg/mL. Adenosine deaminase-stimulated TNF-, production was proportional to parity and unrelated to gestational age, time of delivery, maternal age or indication for amniocentesis. Conclusion, Adenosine deaminase treatment increases TNF-, production by ex vivo -cultured amniotic fluid. Adenosine contributes to immune modulation in the amniotic cavity. [source]

    Adenosine Deaminase Enzyme Therapy Prevents and Reverses the Heightened Cavernosal Relaxation in Priapism

    THE JOURNAL OF SEXUAL MEDICINE, Issue 9 2010
    Jiaming Wen MD
    ABSTRACT Introduction., Priapism featured with painful prolonged penile erection is dangerous and commonly seen in sickle cell disease (SCD). The preventive approaches or effective treatment options for the disorder are limited because of poor understanding of its pathogenesis. Recent studies have revealed a novel role of excess adenosine in priapism caused by heightened cavernosal relaxation, and therefore present an intriguing mechanism-based therapeutic possibility. Aim., The aim of this study was to determine the therapeutic effects of adenosine deaminase (ADA) enzyme therapy to lower adenosine in priapism. Methods., Both ADA-deficient mice and SCD transgenic (Tg) mice display priapism caused by excessive adenosine. Thus, we used these two distinct lines of mouse models of priapism as our investigative tools. Specifically, we treated both of these mice with different dosages of polyethylene glycol,modified ADA (PEG,ADA) to reduce adenosine levels in vivo. At the end points of the experiments, we evaluated the therapeutic effects of PEG,ADA treatment by measuring adenosine levels and monitoring the cavernosal relaxation. Main Outcome Measures., Adenosine levels in penile tissues were measured by high-performance liquid chromatography, and cavernosal relaxation was quantified by electrical field stimulation (EFS)-induced corporal cavernosal strip (CCS) assays. Results., We found that lowering adenosine levels in penile tissues by PEG,ADA treatment from birth in ADA-deficient mice prevented the increased EFS-induced CCS relaxation associated with priapism. Intriguingly, in both ADA-deficient mice and SCD Tg mice with established priapism, we found that normalization of adenosine levels in penile tissues by PEG,ADA treatment relieved the heightened EFS-induced cavernosal relaxation in priapism. Conclusions., Our studies have identified that PEG,ADA is a novel, safe, and mechanism-based drug to prevent and correct excess adenosine-mediated increased cavernosal relaxation seen in two independent priapic animal models, and suggested its therapeutic possibility in men suffering from priapism. Wen J, Jiang X, Dai Y, Zhang Y, Tang Y, Sun H, Mi T, Kellems RE, Blackburn MR, and Xia Y. Adenosine deaminase enzyme therapy prevents and reverses the heightened cavernosal relaxation in priapism. J Sex Med 2010;7:3011,3022. [source]

    Crystallization of the Z, domain of the human editing enzyme ADAR1 complexed with a DNA,­RNA chimeric oligonucleotide in the left-­handed Z-conformation

    ACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2002
    Bernard A. Brown II
    The Z, domain of human double-stranded RNA adenosine deaminase (ADAR1) has been crystallized with a hexanucleotide containing alternating deoxyribose and ribose furanose sugars. Solution circular dichroism experiments show that this double-stranded chimera (dCrG)3 initially adopts the right-handed A-­conformation. However, addition of stoichiometric amounts of Z, causes a rapid transition to the Z-conformation. Raman spectroscopy of crystals of the Z,,(dCrG)3 complex confirm that the chimeric oligonucleotide is stabilized in the Z-conformation. A complete data set has been obtained at 2.5,Å resolution. The Z,,(dCrG)3 crystals belong to the tetragonal I422 space group, with unit-cell parameters a = b = 104.2, c = 117.6,Å. Work is under way to solve the structure by molecular replacement. [source]

    Chemopreventive Task of Capsaicin against Benzo(a)pyrene-induced Lung Cancer in Swiss Albino Mice

    BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2009
    Pandi Anandakumar
    The present study is an effort to identify the chemopreventive role of alkaloid capsaicin against benzo(a)pyrene-induced lung cancer in Swiss albino mice. Benzo(a)pyrene-induced lung cancer-bearing animals showed abnormal changes in body weight, lung weight, tumour incidence and alterations in the activities of marker enzymes adenosine deaminase, aryl hydrocarbon hydroxylase, ,-glutamyl transpeptidase, 5,-nucleotidase and lactate dehydrogenase. On capsaicin pre-co-treatment, all the above alterations were returned to near normal. Immunohistochemical analysis of proliferating cell nuclear antigen together with lung histological examination further supported our biochemical findings that demonstrated the chemoprotective role of capsaicin against benzo(a)pyrene-induced experimental lung cancer. [source]

    3353: Response of the human eye against oxidative stress at high altitudes

    ACTA OPHTHALMOLOGICA, Issue 2010
    S KARAKUCUK
    Purpose To evaluate the response of the anterior segment of the eye against oxidative stress during acute exposure to high altitudes. Methods Forty volunteers were examined and measurements performed at Erciyes University Medical Faculty,Ophthalmology Clinic, Kayseri,Turkey(1080m). On the following day, participants were transported to Mt. Erciyes Ski Center by bus(2200m); thereafter they climbed to an altitude of 2800m.with a moderate pace. Central corneal thickness, intraocular pressure,spheric equivalent of refraction, arterial oxygen pressure,blood pressure, pulse rate and body temperature were measured at both altitudes. Venous blood samples were taken from volunteers at both altitudes;total oxidant status (TOS),total antioxidant status(TAS),advanced oxidation protein products (AOPP), xanthine oxidase (XO), thiol, adenosine deaminase(ADA)levels were investigated at 1080m and 2800m. Results TOS(7.02µmol H2O2 equiv/L, range:0.49-22.07) and AOPP(220.74µmol/L,range:103.81-667.35)significantly increased at high altitude, compared to low altitude levels (3.32µmol H2O2 equiv/L range:0.92-18.41,and 195.58µmol/L,range:84.77-663.16, resp; p<0.05).IOP significantly elevated at high altitude (14.45±3.54mmHg vs 13.22±2.74mmHg; p<0.05). There was a significant positive correlation between IOP and TAS levels(p<0.05). No significant correlation was found between spherical equivalent or central corneal thickness with the investigated oxidation parameters at both altitudes Conclusion We conclude that oxidative stress markers, TOS and AOPP are increased along with IOP during acute exposure to hypoxic environment at high altitudes and that antioxidant system may have a limited capacity to counter balance this effect because of acute unacclimatized ascent. [source]