Search results for " Dono"
showing 10 items of 377 documents
NANC inhibitory neurotransmission in mouse isolated stomach: Involvement of nitric oxide, ATP and vasoactive intestinal polypeptide
2003
1. The neurotransmitters involved in NANC relaxation and their possible interactions were investigated in mouse isolated stomach, recording the motor responses as changes of endoluminal pressure from whole organ. 2. Field stimulation produced tetrodotoxin-sensitive, frequency-dependent, biphasic responses: rapid transient relaxation followed by a delayed inhibitory component. 3. The inhibitor of the synthesis of nitric oxide (NO), L-NAME, abolished the rapid relaxation and significantly reduced the slow relaxation. Apamin, blocker of Ca 2+-dependent K + channels, or ADPβS, which desensitises P 2y purinoceptors, reduced the slow relaxation to 2-8 Hz, without affecting that to 16-32 Hz or the…
Involvement of PKC and NF-κB in Nitric Oxide Induced Apoptosis in Human Coronary Artery Smooth Muscle Cells
2001
Apoptosis of vascular smooth muscle cells is critically involved in progression of atherosclerosis and may prevent intimal hyperplasia in restenosis and vascular remodeling. Nitric oxide (NO) is known to induce apoptosis, but the signaling pathways still remain unclear. We investigated p53 accumulation, protein kinase C (PKC) activation and nuclear transcription factor (NF-kappaB) binding activity as possible signaling mechanisms of NO-induced apoptosis. Apoptosis was induced dose-dependently with the NO-donors sodiumnitroprusside (SNP: 232+/-48%) and SIN-1 (241+/-90% of actinomycin D induced apoptosis; means +/- SEM, *por =0.05 vs. control) in HSMC. Inhibition of PKC significantly attenuat…
Ochratoxin A levels in the plasma of healthy blood donors from Valencia and estimation of exposure degree: comparison with previous national Spanish …
2010
Blood plasma levels of ochratoxin A, a toxic secondary metabolite of several fungal species belonging to the genera Aspergillus and Penicillium, were determined in 168 blood donors from the population of Valencia (Spain) using LC-FLD. In conjunction with blood collection, detailed information on diet was obtained by using a questionnaire that encompassed a wide range of products potentially contaminated with the toxin. The investigation revealed a detection frequency of 100%. Mean level was 1.09 microg OTA/l of plasma and concentrations ranged between 0.15 and 5.71 microg OTA/l of plasma. Men's levels were slightly higher than levels observed in women. Results were analysed by Spearman rank…
In vitro blood brain barrier exposure to mycotoxins and carotenoids pumpkin extract alters mitochondrial gene expression and oxidative stress.
2021
Abstract Food and feed are daily exposed to mycotoxin contamination which effects may be counteracted by antioxidants like carotenoids. Some mycotoxins as well as carotenoids penetrate the blood brain barrier (BBB) inducing alterations related to redox balance in the mitochondria. Therefore, the in vitro BBB model ECV304 was subcultured for 7 days and exposed to beauvericine, enniatins, ochratoxin A, zearalenone (100 nM each), individually and combined, and pumpkin extract (500 nM). Reactive oxygen species were measured by fluorescence using the dichlorofluorescein diacetate probe at 0 h, 2 h and 4 h. Intracellular ROS generation reported was condition dependent. RNA extraction was performe…
Nitric Oxide and Platinum-Derivative-Based Regimens for Cancer Treatment: From Preclinical Studies to Clinical Trials
2017
Abstract Chemoresistance to platinum-based antitumor agents remains a major hindrance faced by patients with a wide variety of solid tumors. New effective strategies are still needed to improve chemosensitization and overcome chemoresistance of tumors by platinum-based chemotherapies. Over the past decade, considerable knowledge on the antitumor effect of nitric oxide (NO) and its mechanisms of action has been gained. Here, we provide an overview of the basic mechanisms of resistance to platinum-based drugs and how NO can bypass this chemotherapy resistance. Preclinical and clinical studies focused on combination therapy using platinum chemotherapeutic drugs with NO donors have demonstrated…
Significance of Various Enzymes in the Control of Mutagenic and Carcinogenic Metabolites Derived from Aromatic Structures
1984
One important early contribution to the control of chemical carcinogenesis is provided by the enzyme pattern responsible for the generation and disposition of reactive metabolites. Especially well studied is the important group of enzymes responsible for the control of reactive epoxides. Many natural as well as man-made foreign compounds, including Pharmaceuticals, possess olefinic or aromatic double bonds. Such compounds can be transformed to epoxides by microsomal monooxygenases present in very many mammalian organs. By virtue of their electrophilic reactivity such epoxides may spontaneously react with nucleophilic centers in the cell and thus covalently bind to DNA, RNA, and protein. Su…
Multiple activation pathways of benzene leading to products with varying genotoxic characteristics.
1989
Abstract Benzene and 13 potential metabolites were investigated for genotoxicity in Salmonella typhimurium and V79 Chinese hamster cells. In the presence of NADPH-fortified hepatic postmitochondrial fraction (S9 mix), benzene reverted his- S. typhimurium strains. The effect was strongest in strain TA1535. Among the potential metabolites, only the trans-1,2-dihydrodiol, in the presence of S9 mix, and the diol epoxides, in the presence and absence of S9 mix, proved mutagenic in this strain. The anti-diol epoxide was more potent than the syn-diastereomer. Both enantiomers of the anti-diastereomer showed similar activities. S9 mix did not appreciably affect the mutagenicity of the anti-diol epo…
A Newly-Detected Reductase fromRauvolfiaCloses a Gap in the Biosynthesis of the Antiarrhythmic Alkaloid Ajmaline
2002
A new enzyme, 1,2-dihydrovomilenine reductase (E.C. 1.3.1), has been detected in Rauvolfia cell suspension cultures. The enzyme specifically converts 2beta( R)-1,2-dihydrovomilenine through an NADPH-dependent reaction into 17-O-acetylnorajmaline, a close biosynthetic precursor of the antiarrhythmic alkaloid ajmaline from Rauvolfia. A five-step purification procedure using SOURCE 30Q chromatography, hydroxyapatite chromatography, 2',5'-ADP Sepharose 4B affinity chromatography and ion exchange chromatography on DEAE Sepharose and Mono Q delivered an approximately 200-fold enriched enzyme in a yield of approximately 6%. SDS-PAGE showed an M r for the enzyme of approximately 48 kDa. Optimum pH …
C21orf2 is mutated in recessive early-onset retinal dystrophy with macular staphyloma and encodes a protein that localises to the photoreceptor prima…
2015
Background/aim We have noted a phenotype of early-onset retinal dystrophy with macular staphyloma but without high myopia. The aim of this study is to report the underlying genetic mutations and the subcellular localisation of the gene product in the retina. Methods Retrospective case series (2012–2015); immunohistochemical analyses of mammalian retina for in situ protein localisation. Results All three probands were first noted to have decreased vision at 3–6 years old which worsened over time. At ages 39, 37 and 12 years old, all had similar retinal findings: dystrophic changes (retinal pigment epithelium mottling, vessel narrowing), macular staphyloma (despite only mild myopia or high hy…
Possible roles of nitric oxide in the physiology and pathophysiology of the guinea pig cochlea.
2000
Two nitric oxide synthase isoforms (NOS-I and NOS-III) are present in the mammalian cochlea, and many regulatory functions of the inner ear could be mediated by NO. In this study, cochlear potentials and immunohistochemical measures were analyzed by changing the concentration of NO in the guinea pig during intracochlear and intravenous application of an NOS inhibitor and an NO donor. In anesthetized guinea pigs the NOS inhibitor NG-nitro-L-arginine-methylester (L-NAME) was applied by intracochlear perfusion or intravenously. The cochlear potentials and blood pressure were measured during and after the application. Cochleae were removed and prepared for morphological and immunohistochemical …